CN1738983A - Worm speed reducer and electric power steering device - Google Patents

Worm speed reducer and electric power steering device Download PDF

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Publication number
CN1738983A
CN1738983A CN 200480002269 CN200480002269A CN1738983A CN 1738983 A CN1738983 A CN 1738983A CN 200480002269 CN200480002269 CN 200480002269 CN 200480002269 A CN200480002269 A CN 200480002269A CN 1738983 A CN1738983 A CN 1738983A
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China
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mentioned
worm
gear
shaft
worm shaft
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CN 200480002269
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CN100476241C (en
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濑川彻
力石一穗
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NSK Ltd
NSK Steering Systems Co Ltd
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NSK Ltd
NSK Steering Systems Co Ltd
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Publication of CN1738983A publication Critical patent/CN1738983A/en
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Abstract

A torsion coil spring (30) applies an elastic force to a worm shaft (29) in a direction towards a worm wheel, via a pre-load pad (70). The pre-load pad (70) restricts displacement in relation to the widthwise direction, by one side face portion of a holder (61) fixed to a gear housing (22). Due to the elastic deformation of the pre-load pad (70) itself based on the elastic force of the torsion coil spring (30), the side face of the pre-load pad (70) is abutted against the one side face portion of the holder (61), so that a gap between the pre-load pad (70) and the one side face portion is minimized. As a result, the occurrence of a teeth fitting noise in the worm reduction gear (16) is suppressed.

Description

Worm speed reducer and electric type power steering device
Technical field
According to worm speed reducer of the present invention and electric type power steering device, for example, the steering gear by the automobile of packing into, with the output of motor as auxiliary power, in the hope of alleviating the needed power of driver's operation steering wheel.In addition, according to worm speed reducer of the present invention, except that electric type power steering device, can also be encased in the linear actuator in the various mechanical devices such as being installed in beddo, electronic desk, electronic chair, lift and use.
Background technique
When giving deflecting roller (the special vehicle, being generally front-wheel),, be extensive use of power steering gear as alleviating the device that the required power of driver's operation steering wheel is used with steering angle except that fork truck etc.In addition, in this power steering gear, the electric type power steering device as auxiliary power source use motor also begins to popularize in recent years.Electric type power steering device is compared with oil pressure dynamic steering device, and having can miniaturization, lightweight, carries out the control of the size (torque) of auxiliary power easily, and, advantage such as the power loss of motor is little.Figure 46 represents the basic structure that the past of this electric type power steering device is known briefly.
On intermediate portion according to the steering shaft 2 of the rotation of the operation of steering wheel 1, torque sensor 3 and retarder 4 are set, wherein, described torque sensor 3 is used to detect direction and the size that is applied to the torque on this steering shaft 2 from this steering wheel 1.The outlet side of this retarder 4 is attached on the intermediate portion of above-mentioned steering shaft 2, and its input side is attached on the running shaft of motor 5.In addition, the testing signal of above-mentioned torque sensor 3 is input to control with the signal of the expression speed of a motor vehicle and switches in above-mentioned motor 5 in the controller 6 of usefulness.In addition, as above-mentioned retarder 4, in the past, use usually has big angle of lead, has reversible worm speed reducer with respect to the power transmission direction.That is, will accept the worm gear of member, be fixed on the intermediate portion of above-mentioned steering shaft 2, simultaneously, will be fixed to the worm screw of the worm shaft on the running shaft of above-mentioned motor 5 for the combination that rotating force is given member, with above-mentioned worm gear engagement as rotating force.
When in order to give deflecting roller 14 with steering angle, operate above-mentioned steering wheel 1, when above-mentioned steering shaft 2 was rotated, above-mentioned torque sensor 3 detected the sense of rotation and the torque of this steering shaft 2, and the signal of representing this checkout value is sent to above-mentioned controller 6.Like this, this controller 6 is 5 energisings of above-mentioned motor, via above-mentioned retarder 4, make above-mentioned steering shaft 2 along with based on the identical direction rotation of the sense of rotation of above-mentioned steering wheel 1.Consequently, the front end of above-mentioned steering shaft 2 (underpart of Figure 46) is with than based on the bigger torque rotation of the torque of the power of being given by above-mentioned steering wheel 1.
The rotation of the front end of this steering shaft 2 via universal joint 7 and jack shaft 8, passes to the input shaft 10 of steering gear mechanism 9.This input shaft 10 makes small gear 11 rotations of the above-mentioned steering gear of formation mechanism 9, via tooth bar 12 push-and-pull drag links 13, gives deflecting roller 14 with required steering angle.As from above-mentioned explanation as can be seen, be delivered to torque on the above-mentioned jack shaft 8 from the front end of above-mentioned steering shaft 2 via universal joint 7, bigger than the torque that is applied on the base end part (upper end portion of Figure 46) of above-mentioned steering shaft 2 from above-mentioned steering wheel 1, the degree that is gone out greatly is equivalent to the amount of the auxiliary power that applies via retarder 4 from above-mentioned motor 5.Thereby in order to give above-mentioned deflecting roller 14 with steering angle, the driver dwindles the amount that is equivalent to above-mentioned auxiliary power in order to operate the required power of above-mentioned steering wheel 1.
Under the situation of the electric type power steering device of above-mentioned this existing general use,, use worm speed reducer as the retarder 4 that is arranged between motor 5 and the steering shaft 2.But, on this worm speed reducer, exist inevitable backlash.When worm shaft and the worm gear as the construction element of above-mentioned worm speed reducer, and support bearing equidimension error that these each members use and assembly error etc. when big more, this backlash is big more.And when existing big backlash, the flank of tooth of above-mentioned worm gear and worm screw is sharp impacts each other, and the ear-piercing dental of beating might take place.
For example, because the road surface is coarse etc., when vibrational loading being added on the steering shaft 2, because the ear-piercing dental of beating can take place in the existence of above-mentioned backlash from wheel side.In addition, because the flank of tooth of above-mentioned worm gear and worm screw collides each other, the sense that turns to with wheel steering the time worsens.
Relative therewith, by considering dimensional accuracy each construction element of above-mentioned worm speed reducer is made up rightly, can dwindle above-mentioned backlash.But under this situation of dwindling backlash, the control of dimensional accuracy and assembling work become pretty troublesome, become to cause the cost cause of increased.
And, in recent years, because the tendency that strengthens above-mentioned auxiliary power is arranged, so the friction of the flank of tooth of above-mentioned worm gear and worm screw increases, the above-mentioned backlash of easier generation.When this based on backlash beat in the space in the compartment that dental leaks into automobile the time, can give the passenger unplessantness displeasure.
In addition, as the document of prior art related to the present invention, patent documentation 1～4 is arranged.
Patent documentation 1: the spy opens the 2000-43739 communique
Patent documentation 2: the spy opens the 2002-37094 communique
Patent documentation 3: the spy opens the 2001-322554 communique
Patent documentation 4: the spy opens the 2002-67992 communique
The content of invention
The present invention In view of the foregoing, is for the structure with cheapness, and the ear-piercing dental of beating of engaging piece that is suppressed at worm gear and worm shaft is invented.
Worm speed reducer of the present invention comprises: worm gear, worm shaft, elastomer, this elastomer are given the elastic force that this worm shaft points to the worm gear direction.
At worm speed reducer of the present invention and be equipped with under the situation of electric type power steering device of this worm speed reducer, as mentioned above,, give the elastic force that worm shaft points to the worm gear direction by elastomer.Therefore, utilize cheap structure, can on the engaging piece of these worm gears and worm shaft, give preload, can be suppressed at the ear-piercing generation of beating dental of this engaging piece.
Description of drawings
Fig. 1 is a diagram of a part being represented with cutting open embodiments of the invention 1.
Fig. 2 is the A-A sectional view that omits Fig. 1 of part expression.
Fig. 3 is the amplification view of the left side of Fig. 2.
Fig. 4 is the amplification view of the right-hand part of Fig. 2.
Fig. 5 is the amplification view of the right-hand part of Fig. 4.
Fig. 6 is the B-B sectional view of Fig. 5.
Fig. 7 is the diagram that the assemblying body that preload pad and worm shaft combine is taken out, sees from the forward end of this worm shaft.
Fig. 8 be with retainer and preload pad and turned round the assemblying body that helical spring combines take out, with perspective view from the state representation of the right-hand observation of Fig. 5.
Fig. 9 is the perspective exploded view of Fig. 8.
Figure 10 is the diagram same with Fig. 7 of expression embodiments of the invention 2.
Figure 11 is the diagram that is illustrated in the preload pad that uses in the embodiments of the invention 3.
Figure 12 is with the embodiment's 3 of the state representation of separating retainer and preload pad and is turned round the helical spring perspective view.
Figure 13 is the diagram same with Fig. 6 of expression embodiments of the invention 4.
Figure 14 is retainer and the preload pad that will be in the embodiments of the invention 4 uses and is turned round the diagram that assemblying body that helical spring combines takes out expression.
Figure 15 is the diagram of an example of the structure of the expression periphery that motor and worm speed reducer is arranged on small gear.
Figure 16 is the diagram of an example of the structure of the expression periphery that motor and worm speed reducer is arranged on secondary small gear.
Figure 17 is the diagram same with Fig. 3 of an example of the motor of expression brushless structure.
Figure 18 is a diagram of a part being cut open expression embodiments of the invention 5.
Figure 19 is the C-C phantom of Figure 18.
Figure 20 is the D-D sectional view of Figure 19.
Figure 21 is the sectional view of motor.
Figure 22 is the part enlarged view of Figure 19.
Figure 23 is the E-E sectional view of Figure 22.
Figure 24 is the F-F sectional view of Figure 22.
Figure 25 is the diagram same with Figure 23 of expression embodiments of the invention 6.
Figure 26 is the G-G sectional view of Figure 25.
Figure 27 is the diagram same with Figure 25 of expression embodiments of the invention 7.
Figure 28 is the diagram same with Figure 22 of expression embodiments of the invention 8.
Figure 29 is the H-H sectional view of Figure 28.
Figure 30 is the amplification view of expression I part embodiments of the invention 9, that be equivalent to Figure 19.
Figure 31 is the diagram same with Figure 22 of expression embodiments of the invention 10.
Figure 32 is the amplification view of expression J part embodiments of the invention 11, that be equivalent to Figure 31.
Figure 33 is the diagram same with Figure 32 of expression embodiments of the invention 12.
Figure 34 is the K-K sectional view that only takes out Figure 33 that elastic ring represents.
Figure 35 is the amplification view of expression L part embodiments of the invention 13, that be equivalent to Figure 31.
Figure 36 is the diagram same with Figure 35 of expression embodiments of the invention 14.
Figure 37 is the M-M sectional view of Figure 36.
Figure 38 is the diagram of an example that expression is arranged on motor the structure of small gear periphery.
Figure 39 is the diagram of an example that expression is arranged on motor the structure of secondary small gear periphery.
Figure 40 is the diagram of expression A-A section embodiments of the invention 15, that be equivalent to Fig. 1.
Figure 41 is the N part amplification view of Figure 40.
Figure 42 is the O-O sectional view of Figure 41.
Figure 43 is the P-P sectional view of Figure 41.
The perspective view of the state of Figure 44 before to be expression with bearing cage element and the 4th ball bearing and elastic ring be about to combine.
Figure 45 (a) is that diagram, (b) of the Q-Q section of expression Figure 42 is the diagram of the R-R section of expression Figure 42.
Figure 46 is the integrally-built sketch that expression becomes the electric type power steering device of object of the present invention.
Figure 47 is in order to illustrate when motor when rotation drives on the direction of regulation, and the figure of the direction of the reaction force that applies to worm shaft from worm gear is simple sectional view (a), (b) is the S-S sectional view of (a).
Figure 48 rotates on the direction opposite with prescribed direction when driving in order to illustrate at motor, and the figure of the direction of the reaction force that applies to worm shaft from worm gear is simple sectional view (a), (b) is the T-T sectional view of (a).
Figure 49 be the expression motor reaction force that when both direction rotation drives, from worm gear, is applied to the both direction on the worm shaft and the same diagram of Figure 47 (b).
Figure 50 is the sectional view of an example of the existing structure of expression worm speed reducer.
Figure 51 is the U-U sectional view of Figure 50.
Figure 52 is when being illustrated in transmission of drive force between worm shaft and the worm gear, be applied to the schematic perspective view of the component on these two members.
Figure 53 is explanation at motor when the direction rotation of regulation drives, be applied to the simple sectional view that the direction of the reaction force on the worm shaft is used from worm gear.
To be explanation rotate along the side with regulation when driving at motor Figure 54 in the opposite direction, be applied to the simple sectional view that the direction of the reaction force on the worm shaft is used from worm gear.
Figure 55 is the sectional view of other example of the existing structure of expression worm speed reducer.
Figure 56 is the V-V sectional view of Figure 55.
Symbol description
1 steering wheel, 2 steering shafts, 3 torque sensors, 4 retarders, 5 motor, 6 controllers, 7 universal joints, 8 jack shafts, 9 steering gear mechanisms, 10 input shafts, 11 small gears, 12 tooth bars, 13 drag links, 14 deflecting rollers, 15 steering columns, 16,16a, the 16b worm speed reducer, 17 outer shafts, 18 interior axles, 19 column jackets, 20 inner props, 22, the 22a gear-box, 23 shells, 24 supporting brackets, 26 vehicle bodies, 27 worm screws, 28 worm gears, 29, the 29a worm shaft, 30,30a is turned round helical spring, 31 motor, 32, the 32a running shaft, 33 spline fitted portions, 34 first ball bearings, 35 second ball bearings, 36 the 3rd ball bearings, 37 the 4th ball bearings, 38, the 38a rotor, 39, the 39a stator, 40 base plate, 41 shrinkage pools, 42 spacing wall, 43 iron cores, 44 slits, 45 coils, 46 transducers, 47 brush carriers, 48 brushes, 49 springs, 50 cloudy spline parts, 51 positive spline parts, ring in 52,53 lip parts, 54 outer screw sections, 55 nuts, 56 butterfly springs, 57 outer shrouds, 58 ladder difference portions, 59 bearing hole, 60 outer shrouds, 61 retainers, 62 large-diameter portion, 63 large-diameter portion, 64 linings, 65 interior rings, 67 export-oriented lip parts, 68 minor diameter, 70,70a preload pad, 71, the 71a through hole, 72 shrinkage pools, 73, the 73a fixing part, 75 secondary small gears, 76 damping devices, 77 Hall integrated circuits, 78 encoders, ring in 79,80 outer shrouds, 81 balls, 82 iron cores, 83 coils, 84 permanent magnets, 85 rolling bearings, 86 outer loop orbits, loop orbit in 87,88 retaining rings, 89 conical surfaces, 90 discontinuous portions, 91 planar surface portion, 92 arms, 93a, the 93b conical surface, 94, the 94a contacting part, 95 recesses, 96 through holes, 97 first protuberances, 98 second protuberances, 99 part cylinder faces, 100 first fixed salients, 101 second fixed salients, 104,104a first portion cylinder face, 105,105a second portion cylinder face, 106, the 106a protuberance, 107,107a third part cylinder face, 108, the 108a fixed protrusion, 109 conical surfaces, 110a, the 110b element, 111 recesses, 112a, the 112b planar surface portion, 113 steering shafts, 114 motor, 115 worm speed reducers, 116 worm gears, 117 worm shafts, 118 worm screws, 119 gear-boxes, 120a, the 120b rolling bearing, 121 running shafts, 122 shrinkage pools, 123 elastic force imparting mechanisms, 124 internal side diameter cylindrical part, 125 outside diameter cylindrical part, 126 annulus portions, 127 interior rings, 128 tapped holes, 129 threaded collar, 130 outer shrouds, 131 fastening bodies, 132 springs, 133 side wall surfaces, 134 guide members, 135 main parts, 136 covers, 137 elastic force imparting mechanisms, 138 first interior axles, 139 second interior axles, 140 torsion bars, 141 are turned round helical spring, 142 preload pads, 149, the 149a bearing cage, 150 major diameter tube portions, 151,151a minor diameter tube portion, 152 annulus portions, 154 retaining rings, 155 retaining rings, 158 first through holes, 159 swing axiss, 160 shrinkage pools, 161 second through holes, 162 wall portions, 164 second bearing cages, 165 portions, 166 large-diameter portion, 167 linings, 169 export-oriented lip parts, 171 minor diameter, 172 planar surface portion, 173 arms, 174 through holes, 175 fixing parts, 176 fixed salients, 177 first portion's cylinder faces, 178 second portion cylinder faces, 179 elastic rings, 180 internal side diameter cylindrical part, 181 outside diameter cylindrical part, 182 linking departments, 183 space portions, 184 recesses, 185 splined holes, 186 helical springs, 187 elastic rings, 188 internal side diameter cylindrical part, 189 outside diameter cylindrical part, 190 linking departments, 191 retainers, 192 shrinkage pools, 193 through holes, 194 elastic rings, 195 through holes, 196 lids, 197 portions, 198 protuberances, 199 boards, 200 axial regions, 201 elastic rings, 202 outside diameter cylindrical part, 203 internal side diameter cylindrical part, 204 linking departments, 205 protuberances, 206 through holes, 207 coupling collars, 208 through holes, 209a, the 209b protuberance, 210 shrinkage pools, 211 secondary small gears, 212 damping devices, 213,213a preload pad, 214 lip parts, 215 elastic rings, 216 bearing cages, 217 bearing cage elements, 218 large diameter cylinder portions, 219 small diameter cylinder portions, 220 inward flange portions, 221 fixed grooves, 222 otch, 223 half-round, 224 spring shackles, 225 linings, 226 large diameter cylinder portions, 227 small diameter cylinder portions, 228 gaps, 229 supporting axles, 230 fixed salients, 231 through holes, 232 conical surfaces, 233 plat parts, 234 planar surface portion, 235 kinks.
Embodiment
Worm speed reducer of the present invention comprises: worm gear, worm screw and elastomer, this elastomer are given the elastic force that points to this worm gear direction on this worm shaft.
When implementing worm speed reducer of the present invention, preferably, on worm shaft, give the elastic force of pointing direction worm gear via the preload pad with aforementioned elastomer.In addition, this worm gear freely is fixed on the auxiliary axis.In addition, for above-mentioned worm shaft, when utilizing pair of bearings that its part near two ends is bearing in the inboard of gear-box, be arranged on the worm screw and the engagement of above-mentioned worm gear of intermediate portion.In addition, for above-mentioned preload pad, utilization is arranged on gear-box or is fixed on guide surface on the member on this gear-box, limit its displacement with respect to prescribed direction, simultaneously, according to above-mentioned elastomeric elastic force,, eliminate or dwindle the gap of this preload pad and above-mentioned guide surface by the resiliently deformable of preload advance capital for body.
In addition, under the situation of implementing worm speed reducer of the present invention, preferably, on worm shaft, give the elastic force of pointing direction worm gear via the preload pad with aforementioned elastomer.In addition, this worm gear freely is fixed on the auxiliary axis.In addition, constitute above-mentioned preload pad with a pair of element, utilization is arranged on gear-box or is fixed on guide surface on the member on this gear-box, limit its displacement with respect to prescribed direction, simultaneously, according to above-mentioned elastomeric elastic force,, eliminate or dwindle the gap of this preload pad and above-mentioned guide surface by making above-mentioned a pair of element to the direction displacement of leaving mutually.
By this structure, when motoring, by the reaction force that is applied to from worm gear on the worm shaft, under the situation of not damaging above-mentioned inhibition effect of beating dental, suppress because ear-piercing unusual sound (noise) generation that the collision of preload pad and guide surface causes.
That is, said structure is a purpose to solve following problem.
At first, as prior art, in patent documentation 1, put down in writing the worm speed reducer of the backlash of considering the engaging piece place that dwindles worm gear and worm shaft.This worm speed reducer, be encased in the electric type power steering device together with motor etc., utilize the worm speed reducer will be, thereby obtain assist torque, give above-mentioned steering shaft this assist torque according to the rotational delay that turns to the motor that torque takes place that is applied on the steering shaft.Therefore, the outer embedding of the worm gear that constitutes above-mentioned worm speed reducer is fixed on the part of this steering shaft, simultaneously, worm shaft is engaged on this worm gear.Two ends of this worm shaft, but the inboard of a pair of rolling bearing free rotary ground supporting utilized at gear-box.In addition, motor is attached on this gear-box.In two ends of above-mentioned worm shaft, utilize the end of spline with this motor side, be attached on the end of running shaft of this motor.
In addition, on the part of said gear case, with the part of above-mentioned motor opposition side on, be provided with along with the tapped hole of the direction of above-mentioned worm shaft quadrature, nut member is attached on the outer end of this tapped hole.In addition, in the inboard of this tapped hole, can the spring retaining member be set with displacement along the axial direction freedom, simultaneously, an end face of above-mentioned spring retaining member is collided with the side of a rolling bearing in above-mentioned a pair of rolling bearing and above-mentioned motor opposition side.And, utilize another end face and the helical spring between the above-mentioned nut, this spring retaining member and the above-mentioned rolling bearing that are arranged on this spring retaining member, on another end of above-mentioned worm shaft, give the elastic force that points to the worm gear direction.
According to the worm speed reducer of record in this patent documentation 1, owing to the backlash that is present in the engaging piece of worm speed reducer can be dwindled certain degree that is suppressed to, so, the dental of beating that takes place in this worm speed reducer can be suppressed to certain degree.As being suppressed at the structure that dental is beaten in generation in the worm speed reducer part, except that the structure that above-mentioned patent documentation 1 is put down in writing, the structure of record also is known in the patent documentation 2.
Under the situation of the worm speed reducer that above-mentioned patent documentation 1 is put down in writing, also as in the patent documentation 2 record, the spring retaining member can free displacement along the radial direction of worm shaft in the inboard of tapped hole,, the flank of tooth of the worm and worm wheel of this worm shaft reverses with respect to sense of rotation respectively.Therefore, when from this worm shaft when this worm gear transmits the driving force of motor, at the engaging piece of this worm gear and above-mentioned worm screw, apply the reaction force of the direction of reversing with respect to the radial direction of this worm shaft to above-mentioned worm shaft from this worm gear.And based on this reaction force, by the power that applies to above-mentioned spring retaining member from an above-mentioned rolling bearing, there is the possibility of the inner peripheral surface that collides this tapped hole tempestuously in this spring retaining member to the radial direction displacement of above-mentioned tapped hole.Like this, collide tempestuously at the spring retaining member under the situation of tapped hole, ear-piercing unusual sound (noise) takes place easily.
In addition, this unusual sound, under the situation that worm gear rotates along the direction of regulation, easier generation.Its reason will be described below.Consideration shown in Figure 47,48, utilize rolling bearing 85 can rotate freely with respect to not shown standing part and slightly the swing support worm shaft 29 with displacement an end { left parts of Figure 47 (a), 48 (a) } time situation.In addition, make the worm screw of the intermediate portion that is arranged on above-mentioned worm shaft 29, with worm gear 28 engagements.In this state, when driving this worm shaft 29, when above-mentioned worm gear 28 transmission of drive force, apply reaction force to this worm shaft 29 by this worm gear 28 from this worm shaft 29 by rotation.In addition, under the situation shown in Figure 47 and under the situation shown in Figure 48, give these worm shaft 29 sizes identical driving force along mutually opposite direction.Therefore, above-mentioned worm gear 28, under the situation shown in Figure 47 and under situation shown in Figure 48, opposite spin mutually.In this state, at the engaging piece of above-mentioned worm gear 28 with worm screw, apply reaction force on apparent from this worm gear 28 to above-mentioned worm shaft 29, described reaction force has respectively as Fx, the Fy of the composition of Figure 47,48 x, y, three directions of z, the component of Fz.Among these component Fx, Fy, the Fz, as Fx, Fz with respect to the component of the direction of the radial direction quadrature of above-mentioned worm gear 28, at as shown in figure 47 worm gear 28 under the situation of a direction { direction shown in the arrow イ of Figure 47 (a) } rotation, and at as shown in figure 48 worm gear 28 under the situation of another direction { direction shown in the arrow ロ of Figure 48 (a) } rotation, the direction of changeabout mutually.
On the other hand, the distance around the radial direction of this worm shaft 29 at the oscillation center o that makes above-mentioned engaging piece and above-mentioned worm shaft 29 is d 29Situation under, size is d 29The moment M of Fx affacts on the above-mentioned worm shaft 29.Therefore, the distance of the axial direction that centers on this worm shaft 29 of the oscillation center o of above-mentioned in season worm shaft 29 is L 29Situation under because above-mentioned moment M, size is M/L 29Power Fr, affact this worm shaft 29 in the radial direction.This power Fr, under the situation shown in Figure 47 and under the situation shown in Figure 48, direction is opposite mutually.Therefore, engaging piece at this worm shaft 29, affact the size of power Fy ' of the reality of y direction on the above-mentioned worm shaft 29, that consider moment M from above-mentioned worm gear 28, worm gear 28 as shown in figure 47 under the situation of direction rotation, diminish, become (Fy '=Fy-Fr), as shown in figure 48 under the situation of another direction rotation, become big, become (Fy '=Fy+Fr).Thereby, affact the size of the F ' that makes a concerted effort of component of y, the z direction of the reality on the engaging piece of above-mentioned worm shaft 29, at worm gear 28 under the situation of direction rotation, diminishing shown in the arrow Ha of Figure 49, when worm gear 28 during, shown in the arrow ニ of this figure, become big to the rotation of another direction.Like this, at worm gear 28 under the situation of another direction rotation, when affacting power F ' on the worm shaft 29 when becoming big from worm gear 28 at above-mentioned engaging piece, the power that affacts on the not shown spring retaining member also becomes big, wherein, this spring retaining member is given elastic force via rolling bearing to another end { right part of Figure 47 (a), Figure 48 (a) } of this worm shaft 29.And this spring retaining member collides inner peripheral surface of not shown tapped hole etc. tempestuously, limit on the part of displacement of this spring retaining member, and unusual sound takes place easily.
In addition, in patent documentation 2, put down in writing, suppressed the structure of above-mentioned unusual sound by between the inner peripheral surface of the outer circumferential face of fastening body and shell, elastomer being set.But the structure of record in the above-mentioned patent documentation 2 increases with respect to the resistance of the displacement of the axial direction of above-mentioned fastening body, because the backlash of engaging piece, might damage the inhibition effect of abnormal sound.
In light of this situation, in order to suppress the generation of beating dental of worm speed reducer, and the utilization other member different structure of on worm shaft, giving elastic force with resilient member, suppress because the generation of the abnormal sound that the part collision of described other member and the displacement that limits this other member causes, invented according to the worm speed reducer of said structure of the present invention and the electric type power steering device of this retarder is housed.
And, according to said structure of the present invention, with respect to from above-mentioned worm gear to the reaction force that above-mentioned worm shaft applies, action direction perpendicular to the central shaft of this worm shaft, this worm shaft and preload pad are arranged under the locational situation of symmetry, when applying above-mentioned reaction force, can be easy to make this preload pad to produce big resiliently deformable.Therefore, can relax from this preload pad and be applied to impact force on the guide surface.Thereby, can more effectively suppress because this preload pad collides the generation of the above-mentioned abnormal sound that this guide surface causes.
In addition, under the worm speed reducer institute situation of implementing according to said structure of the present invention, more preferably, make the above-mentioned preload pad can be, with respect to the central shaft that comprises above-mentioned worm shaft and be arranged on worm screw on this worm shaft and the imaginary plane inclination of the engaging piece of above-mentioned worm gear along the direction of above-mentioned guide surface displacement.
According to this preferred structure, by make because of the sense of rotation of worm gear different different, be applied to the direction of the reaction force on the worm shaft and preload pad the angle that direction of displacement constituted from this worm gear when the motoring along guide surface, with the orientation independent of these reaction forces and equate basically, the difference that the elastic deformation amount that can dwindle the preload pad that is caused by this reaction force at an easy rate causes because of the difference of this direction.Therefore, the impact force in the time of can being easy to dwindle this preload pad and colliding above-mentioned guide surface more effectively suppresses the generation of above-mentioned abnormal sound because of the difference that the difference of above-mentioned direction causes.
In addition, electric type power steering device of the present invention comprises: rearward end be provided with steering wheel steering shaft, be arranged on the forward end of this steering shaft small gear, with this small gear or be bearing in the member engagement on this small gear tooth bar, according to worm speed reducer, the rotation of above-mentioned any structure of the present invention drive motor that worm shaft uses, detect the torque sensor of the direction that is applied to the torque on above-mentioned steering shaft or the small gear and big or small usefulness, according to the controller of using from the drive condition of the above-mentioned motor of SC sigmal control of this torque sensor input.In addition, above-mentioned auxiliary axis is above-mentioned steering shaft, above-mentioned small gear, at any one member in the secondary small gear on the above-mentioned tooth bar of being engaged to away from the position of this small gear.
In addition, under the situation of implementing worm speed reducer of the present invention, preferably, with elastomer as the elastic force imparting mechanism, with worm shaft rotatable and swing supporting with displacement, simultaneously, the worm and wheel engagement of intermediate portion will be arranged on respect to gear-box, from the central shaft of this worm shaft on the position that above-mentioned worm gear lateral deviation is moved, with the central axes of this worm gear the oscillation center axle of above-mentioned worm shaft is set.
According to this preferred construction, in the electric type power steering device of above-mentioned worm speed reducer of packing into, can suppress to make that steering wheel rotates needed power and this steering wheel returns the difference of performance on two sense of rotation.
That is, under the situation of said structure, to solve problem described below as purpose.
At first, as prior art, in patent documentation 3, put down in writing and considered the worm speed reducer that dwindles at the backlash of the engaging piece of worm gear and worm shaft.Shown in Figure 50～51, this worm speed reducer, be encased in the electric type power steering device together with motor 114, give above-mentioned steering shaft 113 with assist torque, described assist torque is by utilizing worm speed reducer 115 to obtain according to the rotational delay that is applied to the above-mentioned motor 114 that turns to the torque generation on the steering shaft 113.Therefore, the worm gear 116 outer embeddings that constitute above-mentioned worm speed reducer 115 are fixed on the part of this steering shaft 113, simultaneously, the worm screw 118 of worm shaft 117 are engaged on this worm gear 116.Two ends of this worm shaft 117, but a pair of rolling bearing 120a, 120b free rotary ground supporting inboard utilized at gear-box 119.In addition, the base portion (left part of Figure 50) of above-mentioned worm shaft 117 is attached on the end (right part of Figure 50) of running shaft 121 of above-mentioned motor 114.
In addition, at the outer circumferential face of the front end (right part of Figure 50) of above-mentioned worm shaft 117 be arranged between the inner peripheral surface of the shrinkage pool 122 on the said gear case 119, rolling bearing 120b and elastic force imparting mechanism 123 among above-mentioned a pair of rolling bearing 120a, the 120b are set.This elastic force imparting mechanism 123, by constituting with the bottom: respectively by metal internal side diameter cylindrical part 124 and outside diameter cylindrical part 125, with described two cylindrical part 124,125 link by rubber or plastic annulus portion 126.In addition, make above-mentioned internal side diameter cylindrical part 124 with respect to above-mentioned external diameter cylindrical part 125 to the above-mentioned worm gear 116 lateral deviation hearts.And, outside diameter cylindrical part 125 embedded being fixed in the above-mentioned shrinkage pool 122 with above-mentioned elastic force imparting mechanism 123, simultaneously, be fixed on the interior ring 127 of a fixing rolling bearing 120b of the inboard of above-mentioned internal side diameter cylindrical part 124 front end of above-mentioned worm shaft 117 is embedded.By this structure, on the front end of above-mentioned worm shaft 117, give the elastic force of the direction of pointing to above-mentioned worm gear 116 (Figure 50,51 the direction that makes progress), above-mentioned worm shaft 117 is in these worm gear 116 side oscillation displacements.In addition, the front-end face that is attached to the threaded collar 129 on the tapped hole 128 of said gear case 119 is pressed on the face (left side of Figure 50) of another rolling bearing 120a base end part, among above-mentioned a pair of rolling bearing 120a, the 120b of this worm shaft 117 of supporting.And, by this structure, dwindle the internal void of the axial direction of above-mentioned a pair of rolling bearing 120a, 120b, suppress rocking of described each rolling bearing 120a, 120b.
According to the worm speed reducer of this record in patent documentation 3, owing to can suppress to be present in the worm screw 118 of worm shaft 117 and the backlash of the engaging piece of worm gear 116 to a certain extent, so, can be suppressed at the dental of beating of this engaging piece to a certain extent.
Under the situation of the worm speed reducer that above-mentioned patent documentation 3 is put down in writing, worm shaft can be swung supporting with displacement with respect to gear-box 119.But, at central shaft with the swing displacement of this worm shaft 117, be arranged under the locational situation of the point on the central shaft of this worm shaft 117 at center etc. of the rolling bearing 120a that uses by the base end part that supports this worm shaft 117, exist the problem that produces difference in the return course on two sense of rotation of unshowned steering wheel in the drawings.In addition, exist the needed power of driver's operation steering wheel in problem such as the difference of two sense of rotation is big.Below, its reason is described.
At first, utilize the sketch of Figure 52 (a) shown in (b), consider to utilize motor 114 rotations to drive worm shafts 117, driving force is passed to the situation of worm gear 116 from this worm shaft 117.At (a) of Figure 52 with (b), drive above-mentioned motor 114 with identical size rotation round about.In addition, Figure 52 (a) (b) in, the shaft angle that makes worm shaft 117 and worm gear 116 be 90 the degree.In this state, the flank of tooth of the worm and worm wheel 116 of these worm shafts 117 reverses with respect to the central shaft of these worm shafts 117 and worm gear 116, simultaneously, exists pressure angle on these flank of tooth.Therefore, apply reaction force to above-mentioned worm shaft 117 from this worm gear 116, this reaction force have along the axial direction of this worm shaft 117 and radial direction and with the component Fa of the composition of three directions of the tangent direction of the pitch circle of above-mentioned worm screw 1, Fr 1, Fu 1
In addition, at these component Fa 1, Fr 1, Fu 1In, the component Fa of the axial direction of above-mentioned worm shaft 117 1, with the component Fu that is applied to along the tangent direction of the pitch circle of this worm gear 116 from this worm shaft 117 on the above-mentioned worm gear 116 2Direction is opposite, and size is identical.In addition, the component Fr of the radial direction of above-mentioned worm shaft 117 1, be applied to component Fr on this worm gear 116 with radial direction from this worm shaft 117 along above-mentioned worm gear 116 2Direction is opposite, and size is identical.In addition, the component Fu of the tangent direction of above-mentioned worm screw 1, be applied to component Fa on this worm gear 116 with axial direction from above-mentioned worm shaft 117 along above-mentioned worm gear 116 2Direction is opposite, and size is identical.According to this situation, under the situation of the structure shown in Figure 50,51, even at the component Fr of above-mentioned radial direction 1When being applied on the above-mentioned worm shaft 117, because the flank of tooth of the worm and worm wheel 116 of this worm shaft 117 can not separate each other yet, so,, on above-mentioned worm shaft 117, give the elastic force of the suitable size of the direction of pointing to above-mentioned worm gear 116 by elastic force imparting mechanism 123 (Figure 50,51).
In addition, be applied to reaction force on the above-mentioned worm shaft 117, affact from the central shaft of this worm shaft 117 on the engaging piece of these worm gear 116 lateral deviations worm screw that move, this worm shaft 117 and this worm gear 116 from above-mentioned worm gear 116.Therefore, be arranged in oscillation center under the locational situation of the central shaft by this worm shaft 117, by the component Fa of above-mentioned axial direction with this worm shaft 117 1,, affact on this worm shaft 117 with the moment of this oscillation center as its center.In addition, at above-mentioned worm shaft 117 under the situation of both direction rotation, the direction of this moment, the direction of changeabout.About this point, utilize Figure 53,54 to describe in further detail.
In Figure 53,54, utilize rolling bearing 120a, rotatably and can swing slightly with displacement as its center with the center o of this rolling bearing 120a the base end part of worm shaft 117 (Figure 53,54 left part) is bearing on the not shown fixing part.In addition, under the situation shown in Figure 53 and under the situation shown in Figure 54, drive above-mentioned worm shaft 117 with opposite direction, identical size rotation.In this state, at the worm screw of this worm shaft 117 and the engaging piece of this worm gear 116, under the situation shown in Figure 53 and under the situation shown in Figure 54, for the axial direction of this worm shaft 117, direction opposite reaction Fa 1, be applied on this worm shaft 117 from this worm gear 116.In addition, the distance with respect to the radial direction of this worm shaft 117 at the oscillation center o that makes above-mentioned engaging piece and above-mentioned worm shaft 117 is d 117Situation under, size is d 117Fa 1Moment M affact on the above-mentioned worm shaft 117.The direction of this moment M is under the situation shown in Figure 53 and under the situation shown in Figure 54, opposite mutually.And, be L in the distance of the oscillation center o that makes above-mentioned engaging piece and above-mentioned worm shaft 117 with respect to the axial direction of this worm shaft 117 117Situation under, size is M/L 117Power Fm, affact this worm shaft 117 in the radial direction at above-mentioned engaging piece.In addition, the action direction of this power Fm is under the situation shown in Figure 53 and under the situation shown in Figure 54, opposite mutually.Therefore, radially affact the power Fr of reality on the above-mentioned worm shaft 117, that consider above-mentioned moment M from above-mentioned worm gear 116 at above-mentioned engaging piece 1' size, shown in Figure 53, under the situation of direction rotation, diminish at worm gear 116, become (Fr 1'=Fr 1-Fm), and under the situation shown in Figure 54, when worm gear 116 during to the rotation of another direction, the power Fr that this is actual 1' size become big, become (Fr 1'=Fr 1+ Fm).
Like this, radially affact the power Fr of the reality on the above-mentioned worm shaft 117 at above-mentioned engaging piece 1' become big, above-mentioned worm gear 116 under the situation of another one direction rotation (situation shown in Figure 54), the flank of tooth of the worm screw of above-mentioned worm shaft 117, the flank of tooth from above-mentioned worm gear 116 separates easily.On the other hand, when strengthening the power that these flank of tooth are pressed against each other, the rotating torques of above-mentioned worm gear 116 and worm shaft 117 increases.Because this situation, when above-mentioned worm gear 116 during to the rotation of other direction, consider simultaneously to satisfy and do not make the requirement that separated from one another and these flank of tooth impacting force each other of the above-mentioned flank of tooth can be not excessive, be necessary to set appropriate value for utilizing the elastic force imparting mechanism to give the elastic force of above-mentioned worm shaft 117.But,, under the situation of a direction rotation, can not avoid above-mentioned each flank of tooth impacting force each other to become excessive at above-mentioned worm gear 116 even when setting above-mentioned elastic force like this.Therefore, make automobile when turning driving turns back to straight-line travelling, the performance of returning that steering wheel returns the neutral state worsens in a direction, the driver makes the required power of this steering wheel rotation become excessive in a direction, can produce to return performance and power and become problem such as big in the difference of two sense of rotation of this steering wheel.
In light of this situation, the generation of beating dental for the engaging piece of the worm and wheel that is suppressed at worm shaft, and in order to utilize the structure of on this worm shaft, giving the elastic force that points to this worm gear direction, suppress to make that the member of fixing this worm gear rotates that needed power and the rotation of this member turn back to the neutral state returns the difference of performance two sense of rotation, invented according to the worm speed reducer of said structure of the present invention and the electric type power steering device of this retarder is housed.
Under the situation of the worm speed reducer of said structure, with the oscillation center axle of worm shaft, from the central shaft of this worm shaft on the position that the worm gear lateral deviation is moved, be provided with the central axes ground of this worm gear.Therefore, from this worm shaft during to the worm gear transmission of drive force, though apply along the reaction force of the axial direction of this worm shaft to this worm shaft from this worm gear,, the moment that takes place on this worm shaft that the reaction force owing to this axial direction can be caused is dwindled or made it is 0.Thereby, can suppress since this moment influence caused is applied to the variation of the reaction force of the radial direction on the above-mentioned worm shaft from above-mentioned worm gear.And, whereby, can suppress to make that the member of fixing above-mentioned worm gear rotates that needed power and this member rotate to the neutral state returns the difference of performance on two sense of rotation.Consequently, under the situation of the electric type power steering device of the aforesaid worm speed reducer of the present invention of packing into, can suppress to make that steering wheel rotates needed power and steering wheel returns the difference of performance on two sense of rotation.
In addition, state on the implementation under the situation of worm speed reducer of structure, more preferably, will by with the straight line of the central axes of above-mentioned worm shaft on 1 point and with the axle of the central axes of this worm gear, swing axis as above-mentioned worm shaft, wherein, described straight line comprises the intersection point of the pitch circle of the worm screw of above-mentioned worm shaft and above-mentioned worm gear.
According to this preferred construction, with driving force when above-mentioned worm shaft passes to above-mentioned worm gear, although from this worm gear, apply along the reaction force of the axial direction of this worm shaft to this worm shaft, but, can eliminate (make it is 0) because the problem that moment takes place that the reaction force of this axial direction causes on this worm shaft.That therefore, can eliminate that the required power of the member rotation that makes fixing above-mentioned worm gear and this member rotate to the neutral state returns the difference of performance on two sense of rotation.
In addition, more preferably, but at least one bearing cage near the pair of bearings of the part the close two ends of the above-mentioned worm shaft of free rotary ground supporting can be able to be swung supporting with displacement with respect to the said gear case.
According to this preferred construction, as one of them above-mentioned bearing, can use the bearing that usually uses in the prior art, described one of them bearing can be able to be swung supporting with displacement with respect to gear-box, can suppress the rising of cost.
More preferably, for the axial direction of above-mentioned worm shaft, but the oscillation center axle of this worm shaft is arranged between the engaging piece of the worm screw of the bearing of the motor side in the pair of bearings of close two end portions of this worm shaft of free rotary ground supporting and this worm shaft and worm gear.
According to this preferred structure, though reduced the swing displacement amount of end of the motor side of worm shaft, but the worm and wheel engaging piece that can give this worm shaft can more effectively be suppressed at the ear-piercing generation of beating dental of this engaging piece with big preload.
More preferably, in any worm speed reducer of said structure, with respect to the worm screw of above-mentioned worm shaft and the engaging piece of worm gear,, be provided with and give the elastic force imparting mechanism that this worm shaft is used with the elastic force that points to this worm gear direction at the opposition side of the oscillation center axle of this worm shaft.
According to this preferred structure, can strengthen the elastomeric elastic deformation amount who constitutes the elastic force imparting mechanism, the size that can be easy to regulate the elastic force of giving above-mentioned worm shaft.
More preferably, in any worm speed reducer of said structure, but with the bearing cage of supporting free rotary ground supporting near the part usefulness of an end of above-mentioned worm shaft, utilize swing axis to swing and be bearing in displacement on the said gear case, simultaneously, between described gear-box and the swing axis or between described bearing cage and swing axis, elastic material is set.
According to this preferred structure, the rotating torques of worm shaft is bootlessly increased, can be suppressed at the dental of beating of above-mentioned engaging piece.That is, under the situation that worm shaft can not support with respect to axial direction with displacement with respect to gear-box, when whirling vibration was input on the worm gear, above-mentioned worm shaft was rotated motion easily.In addition, owing on this worm shaft, link the running shaft that the big motor of moment of inertia is arranged, so because the whirling vibration of above-mentioned worm gear, the power of transmitting between the flank of tooth of the worm screw of this worm shaft and above-mentioned worm gear becomes big.Thereby, even applying under the situation of this power,, be necessary to strengthen the elastic force that utilizes above-mentioned elastic force imparting mechanism to give for described two flank of tooth do not separate each other, still, under the excessive situation of this elastic force, the rotating torques of above-mentioned worm shaft bootlessly increases.Relative therewith, according to the worm speed reducer of said structure of the present invention,, can be easy to above-mentioned worm shaft can make this worm shaft be difficult to be rotated motion to the axial direction displacement under the situation of above-mentioned worm gear input whirling vibration.Therefore, can dwindle the power of between above-mentioned two flank of tooth, transmitting.Consequently, can bootlessly not increase the rotating torques of above-mentioned worm shaft, can prevent that described two flank of tooth are separated from one another, can suppress above-mentioned generation of beating dental.And then the vibration that the collision by described two flank of tooth is caused is difficult to be delivered on the said gear case, can suppress because the generation of the abnormal sound that this vibration causes.
In addition, under the situation of enforcement according to the worm speed reducer of said structure of the present invention, preferably, the bearing cage of using near the bearing of the part of an end of above-mentioned worm shaft can be freely supported in supporting, utilize swing axis to swing and be bearing in displacement on the said gear case, between described gear-box and swing axis, the elastic ring that at least a portion is an elastic material perhaps is set between described bearing cage and swing axis, simultaneously, make the rigidity of the above-mentioned elastic ring relevant, difference in a circumferential direction with the radial direction of above-mentioned worm shaft.
According to this preferred construction, by reducing the rigidity of the above-mentioned elastic ring relevant with the axial direction of above-mentioned worm shaft, under the situation of the necessary rigidity of the integral body of guaranteeing this elastic ring, can be easy to make above-mentioned worm shaft along axial direction with respect to the gear-box displacement.Thereby, can more effectively suppress the increase of the rotating torques of this worm shaft.
In addition, state on the implementation under the situation according to any worm speed reducer of structure of the present invention, preferably, between the running shaft of above-mentioned worm shaft and motor, the elastic force imparting mechanism that the elastic force of giving the direction of pointing to above-mentioned worm gear on this worm shaft is used is set.
According to this preferred construction, in the generation that suppresses abnormal sound,, can use the internal void ball bearing bigger, shallow/deep groove type of axial direction, in the hope of reducing cost as the bearing that the end of the motor side that supports worm shaft is used.
In addition, under the situation of enforcement according to any worm speed reducer of the structure of the invention described above, preferably, between bearing cage and said gear case, the elastic force imparting mechanism that this worm shaft is used with the elastic force that points to above-mentioned worm gear direction is given in setting, wherein, described bearing cage, but be used for supporting free rotary ground supporting at least one bearing near the pair of bearings of the two end portions of above-mentioned worm shaft.
According to this preferred construction, needn't strengthen the total length of the part of the running shaft that can link above-mentioned worm shaft and motor, the engaging piece that just can give the worm screw of this worm shaft and above-mentioned worm gear is with preload.
In addition, state on the implementation under the situation according to any worm speed reducer of structure of the present invention, preferably, by between supporting is near bearing and said gear case away from above-mentioned oscillation center axle in the pair of bearings of the part at above-mentioned worm shaft two ends, elastic material is set, can makes above-mentioned worm shaft with respect to this gear-box swing displacement.
According to this preferred construction, under the situation of the effect of beating dental that can not damage the engaging piece place that suppresses above-mentioned worm shaft and worm gear, can prevent because the generation of the abnormal sound that this worm shaft causes in the collision of the end of the opposition side of motor and a bearing of this end of supporting.
In addition, under the situation of enforcement according to any worm speed reducer of the structure of the invention described above, preferably, by away from supporting near away between bearing of the oscillation center axle of this worm shaft and the said gear case second elastic ring that at least a portion is the elastic material manufacturing being set in the pair of bearings of the part at the two ends of above-mentioned worm shaft, can make above-mentioned worm shaft with respect to this gear-box swing displacement, simultaneously, make the rigidity of this second elastic ring, different with respect to the rigidity of the swing direction of displacement of this worm shaft with the rigidity of direction with respect to other.
According to this preferred construction, preventing above-mentioned worm shaft in undesirable direction displacement, can more easily make this worm shaft to the displacement of above-mentioned worm gear side, can more effectively suppress the worm screw of this worm shaft and this worm gear engaging piece beat dental.
In addition, state on the implementation under the situation of worm speed reducer of structure, preferably, on the elastic material or second elastic ring be located between an aforementioned bearing and the gear-box, the retainer that the swing displacement of the above-mentioned worm shaft of restriction is used is set.According to this preferred construction, can prevent the displacement component of crossing of above-mentioned worm shaft.
In addition, under the situation of enforcement, preferably, link the running shaft and the worm shaft of above-mentioned motor via elastic material according to any inhibition worm speed reducer of the structure of the invention described above.According to this preferred construction, between the running shaft and worm shaft of above-mentioned motor, be not easy to transmit whirling vibration.
In addition, under the situation of enforcement according to any inhibition worm speed reducer of the structure of the invention described above, preferably, between bearing cage and said gear case, repack with grease, wherein, described bearing cage, but be used for supporting free rotary ground supporting at least one bearing near the pair of bearings of the part at the two ends of above-mentioned worm shaft.
According to this preferred construction, between above-mentioned worm shaft and worm gear during transmission of drive force, owing to the reaction force that is applied to from this worm gear on this worm shaft, this worm shaft has under the situation of the tendency that breaks away from this worm gear, is difficult to above-mentioned bearing cage swing displacement.And, when above-mentioned driving force increase, when above-mentioned reaction force becomes big, the speed that above-mentioned worm shaft breaks away from above-mentioned worm gear has the tendency of increase, but, in this case, because the viscous resistance of above-mentioned lubricating grease also becomes big, so, can suppress the swing displacement of above-mentioned bearing cage.Therefore, can be easy to prevent that the flank of tooth of above-mentioned worm shaft and worm gear is separated from one another.
In addition, under the situation of enforcement according to any inhibition worm speed reducer of the structure of the invention described above, preferably, but support the bearing cage that free rotary ground supporting is used near at least one bearing in the pair of bearings of the two end portions of above-mentioned worm shaft, make with magnesium alloy.
According to this preferred construction, because the vibration that can utilize above-mentioned bearing cage to be easy to absorb the flank of tooth collision each other because of the worm and wheel of above-mentioned worm shaft on this worm shaft, to take place, so, be not easy this vibration transfer to the said gear case.
In addition, according to above-mentioned electric type power steering device of the present invention, comprising: the steering shaft that steering wheel is set in rearward end, be arranged on the small gear of the forward end of this steering shaft, with this small gear or be bearing in the tooth bar of the member engagement on this small gear, any worm speed reducer according to the structure of the invention described above, rotation drives the motor that worm shaft is used, detection is applied to the torque sensor of the direction and the big or small usefulness of the torque on above-mentioned steering shaft or the small gear, according to the controller of using from the drive condition of the above-mentioned motor of SC sigmal control of this torque sensor input.In addition, with above-mentioned worm gear, be fixed to above-mentioned steering shaft, above-mentioned small gear or on leaving the position of this small gear, be engaged in the secondary small gear on the above-mentioned tooth bar on any one.
In addition, under the situation of implementing worm speed reducer of the present invention, preferably, make elastomer give the elastic force that worm shaft points to the direction of worm gear via the preload pad.In addition, this worm gear freely is fixed on the auxiliary axis.In addition, utilize clutch shaft bearing the part near an end of above-mentioned worm shaft to be bearing in the inboard of gear-box, utilize second bearing part of the close the other end of above-mentioned worm shaft to be bearing in the inboard of gear-box, simultaneously, be arranged on the worm screw and the engagement of above-mentioned worm gear of intermediate portion, and, can swing as the center with above-mentioned clutch shaft bearing.In addition, utilize the plastic buffer component be fixed on the said gear case to cover at least a portion of two sides of the outer circumferential face of above-mentioned second bearing and axial direction, limit second bearing with respect to the displacement in axial direction of this buffer component.In addition, allow of the displacement of above-mentioned worm shaft with respect to the axial direction of the above-mentioned preload pad and second bearing.
According to this preferred construction, though apply the power of axial direction from worm gear to worm shaft,, the preload of engaging piece of giving the worm and wheel of this worm shaft can be maintained in the narrow scope at an easy rate.Therefore, can be suppressed at the generation of beating dental of this engaging piece effectively.
That is under the situation of said structure, be purpose, to solve the problem that should solve as described below.
At first, as prior art, in patent documentation 4, put down in writing and considered the worm speed reducer that dwindles at the backlash of the worm meshing portion of worm gear and worm shaft.This worm speed reducer shown in Figure 55,56, utilizes a pair of rolling bearing 120a, 12b, but with respect to the part of gear-box 119 free rotary ground supportings near the two ends of worm shaft 117.Utilization is bearing in the spring 132 on the gear-box 119, fastening body 131 flexibly is pressed on the outer circumferential face of outer shroud 130 of (Figure 55's is right-hand) rolling bearing 120b among described a pair of rolling bearing 120a, the 120b.And,, give the elastic force of the direction of pointing to worm gear 116 to the front end of above-mentioned worm shaft 117 by this structure.In addition, around an above-mentioned rolling bearing 120b, cylindric guide member 134 is set, the radial direction that is used to limit an above-mentioned rolling bearing 120b is the displacement of axial direction, wherein, described cylindric guide member 134, the surface is provided with the pair of sidewalls face 133,133 that is parallel to each other within it.In addition, be pressed on the face of another (left of Figure 55) the rolling bearing 120a among above-mentioned a pair of rolling bearing 120a, the 120b by the front-end face that will be attached to the threaded collar 129 in the tapped hole 128 that is formed on the gear-box 119, dwindle the internal void of above-mentioned another rolling bearing 120a, simultaneously, above-mentioned worm shaft 117 is pressed on the rolling bearing 120b, dwindles the internal void of a described rolling bearing 120b.And by this structure, suppressing a described rolling bearing 120b is rocking of above-mentioned another rolling bearing 120a.The situation of the structure of record is identical in other structure and the patent documentation 3 shown in aforesaid Figure 48～49.
Under the situation of the worm speed reducer of in this patent documentation 4, putting down in writing, the same with the structure of above-mentioned patent documentation 3 records, can give the worm screw 118 of worm shaft 117 and the engaging piece preload of worm gear 116, the backlash that is present in this engaging piece can be dwindled certain degree that is suppressed to, so, the dental of beating that portion's engaging piece takes place can be suppressed to certain degree.
Under the situation of the structure that aforesaid patent documentation 4 is put down in writing,, suppress rocking of above-mentioned each rolling bearing 120a, 120b by strengthening the fastening amount of above-mentioned threaded collar 129.But, when strengthening the fastening amount of above-mentioned threaded collar 129, support the front end end face that use, that constitute the outer shroud 130 of an above-mentioned rolling bearing 120b of this worm shaft 117, be pressed to securely on the bottom surface of guide member 134.And, whereby, between the bottom surface of the end face of described outer shroud 130 and guide member 134, produce big frictional force.The increase of this frictional force becomes by spring 132 being pressed to the outer circumferential face of this outer shroud 130, reduces the reason of the preload of giving above-mentioned engaging piece.In addition, this preload reduces becomes the reason of beating dental in the easy generation of this engaging piece.
Relative therewith, even give the elastic force of above-mentioned outer shroud 130 utilizing above-mentioned spring 132 by increasing, act under the situation that the frictional force between the end face of the end face of above-mentioned outer shroud 130 and above-mentioned guide member 134 increases, also wish to guarantee to give the preload of above-mentioned engaging piece more than specified value.But, when this preload is excessive, the returning performance and can worsen of above-mentioned steering wheel.That is, above-mentioned preload is for the dental of beating that is suppressed at above-mentioned engaging piece applies, but, when this preload becomes specified value when above, with automobile when turn condition turns back to the craspedodrome state, make above-mentioned steering wheel return to the neutral state steering wheel return mis-behave.Therefore, be necessary above-mentioned preload is set in the limited narrow scope.Thereby, be necessary to suppress enough for a short time to the frictional force between the end face of this preload influence end face big, that affact above-mentioned outer shroud 130 and above-mentioned guide member 134.But enough little for this frictional force is narrowed down to, the operation of fastening amount of fine adjusting above-mentioned threaded collar 129 is very difficult.
In addition, be accompanied by the driver, under the situation that motor 114 rotations drive, applying along the big reaction force of the axial direction of this worm shaft 117 to worm shaft 117 from worm gear 116 with wheel steering.And, in effect owing to this reaction force, this worm shaft 117 with respect to axial direction under the situation of guiding member 134 side displacements, support the outer shroud 130 of the above-mentioned rolling bearing 120b that the front end of this worm shaft 117 uses, still be pressed at full tilt on the bottom surface of this guide member 134, the frictional force that occurs between the bottom surface of this outer shroud 130 and this guide member 134 might increase.That is, be difficult to for a long time this frictional force be kept steady state value, under the big situation of this frictional force change, the above-mentioned dental of beating take place easily at above-mentioned engaging piece.Otherwise when this frictional force diminished, the performance of returning of above-mentioned steering wheel was easy to worsen.
In light of this situation, above-mentioned worm speed reducer and the electric type power steering device that this retarder is housed are invented for following purpose, promptly, though by apply the power of axial direction to worm shaft from worm gear, but the preload that still will give above-mentioned engaging piece is stably kept in the limited narrow scope at an easy rate, is suppressed at the generation of beating dental of this engaging piece effectively.
Under the situation of said structure, for giving second bearing that preload pad that worm shaft uses with elastic force and the front end that supports this worm shaft use, allow this worm shaft along the axial direction displacement.Therefore, even under the situation of the big reaction force that applies axial direction from worm gear to this worm shaft, the above-mentioned preload pad and second bearing can not be pressed on the axial direction of this worm shaft owing to this reaction force at full tilt yet.Thereby, give this worm shaft with elastic force by utilizing elastomer via above-mentioned preload pad, the preload that can prevent to give the worm meshing portion of above-mentioned worm gear and worm shaft is subjected to the influence of above-mentioned reaction force and big change takes place.Consequently, can be easy to this preload is maintained in the limited narrow scope long-term and stably, can be suppressed at the generation of beating dental of above-mentioned engaging piece effectively.In addition, make of synthetic resin owing to limit the buffer component of the second bearing displacement, so, dwindle the frictional force that acts between described second bearing and the buffering member, can easily make this second bearing carry out the displacement of radial direction.Therefore, can more effectively be suppressed at the dental of beating of above-mentioned engaging piece generation.In addition, this second bearing, utilize above-mentioned buffer component to cover at least a portion of two sides of its outer circumferential face and axial direction, limit above-mentioned second bearing in axial direction with respect to the displacement of this buffer component, so, above-mentioned worm shaft can be pressed on this second bearing along axial direction, can suppress rocking of this second bearing.
In addition, state on the implementation under the situation of worm speed reducer, more preferably, buffer component is formed on the part of circumferencial direction, the member of the otch of the whole length that spreads all over axial direction is set.
Under this preferred structure situation, can flexibly enlarge the diameter of buffer component, can carry out the operation that is assembled into this buffer component inboard with second easily to limit the mode of this second bearing along the displacement of axial direction.In addition, utilize above-mentioned buffer component can be easy to absorb to be arranged on this buffer component around the size error and the assembly error of parts.In addition,, also the dimensional changes that is arranged on the cut-away portions on this buffer component can be absorbed, the otch dimensional changes in addition of this buffer component can be suppressed even under the situation of temperature variation around.
In addition, more preferably, when stoping second bearing, allow second bearing with respect to of the displacement of this buffer component along the radial direction of this second bearing with respect to the displacement of buffer component on the axial direction of this second bearing.
According to this preferred structure, simultaneously swing under the situation of displacement at worm shaft and the relative displacement in axial direction of second bearing one side, this worm shaft, the sliding friction between the described worm shaft and second bearing can be easy to dwindle, this swing displacement can be carried out very smoothly.Therefore, dwindle whole frictional loss, the engaging piece of worm and wheel that can give this worm shaft is with appropriate preload.
In addition, more preferably, between buffer component and gear-box, perhaps between this buffer component and second bearing, resilient member is set.
According to this preferred structure, can be easy to suppress buffer component with respect to the rocking of gear-box, perhaps suppress second bearing rocking with respect to this buffer component.Therefore, can be easy to carry out the size Control of each several part, simultaneously, can be easy to the engagement of the engaging piece of the worm and wheel of worm shaft is maintained appropriate state.And then, when buffer component being assembled on the gear-box or installing to second bearing pack on this buffer component, can be at described each member pressure elasticity member each other.Therefore, can simultaneously prevent this buffer component or second bearing with respect to the coming off of gear-box or buffer component, one side is carried out the assembling operation of this buffer component or second bearing, can be easy to carry out this assembling operation.
In addition, more preferably, utilize a pair of element to constitute buffer component, the imaginary plane that described a pair of element has by the central shaft that comprises this buffer component is divided into two shapes that obtained.According to this preferred structure, the forming operation in order to obtain buffer component is more prone to, simultaneously, the easier operation of carrying out second bearing pack is installed to the inboard of this buffer component.
In addition, state on the implementation under the situation of structure, preferably, the in-plane that makes a pair of element interface each other is with to utilize elastomer to give the direction of worm shaft elastic force consistent.According to this preferred structure, can carry out the swing displacement of worm shaft easilier.
In addition, under the situation of above-mentioned electric type power steering device, comprise: the steering shaft that steering wheel is set at the rear portion, be arranged on the small gear of the forward end of this steering shaft, with this small gear or be bearing in the tooth bar of the member engagement on this small gear, any worm speed reducer according to said structure of the present invention, rotation drives the motor that worm shaft is used, detection is applied to the torque sensor of the direction and the big or small usefulness of the torque on above-mentioned steering shaft or the small gear, according to the controller of using from the drive condition of the above-mentioned motor of SC sigmal control of this torque sensor input, wherein, auxiliary axis is above-mentioned steering shaft, above-mentioned small gear, on leaving the position of this small gear, be engaged to any one in the secondary small gear on the above-mentioned tooth bar.
Embodiment 1
Fig. 1～9 expression embodiments of the invention 1.The electric type power steering device of present embodiment, comprise: as the steering shaft 2 that steering wheel 1 is fixed to the auxiliary axis on the rearward end, can insert the steering column 15 that connects this steering shaft 2, give the worm speed reducer 16 that steering shaft 2 is used with assist torque, be arranged on the small gear 11 (with reference to Figure 46) of the forward end of this steering shaft 2, with this small gear 11 or be bearing in the tooth bar 12 (with reference to Figure 46) of the member engagement on this small gear 11, torque sensor 3 (with reference to Figure 46), motor 31, controller 6 (with reference to Figure 46).
Steering shaft 2 is wherein utilized spline fitted portion, can free transmission rotating force and can be with respect to the axial direction formation that with displacement outer shaft 17 and interior axle 18 combined.In addition, under the situation of present embodiment,, simultaneously, described end is combined via synthetic resin with the front end of above-mentioned outer shaft 17 and interior 18 rearward end spline fitted.Thereby above-mentioned outer shaft 17 and interior axle 18 make this synthetic resin fracture when collision, can shorten total length.
In addition, insertion is through with the tubular steering column 15 of above-mentioned steering shaft 2, and column jacket 19 and inner prop 20 are combined into the specular formation of looking in the distance, and is formed under the situation of the impact that applies axial direction, one side absorbs by this and impacts the energy that produces, and one side shortens the structure of the so-called extension type of total length.And, the front end combination of above-mentioned inner prop 20 is fixed on the ear end face of gear-box 22.In addition, axle in above-mentioned 18 is inserted the inboard that connects this gear-box 22, make the front end of axle 18 in this outstanding from the front-end face of this gear-box 22.
Above-mentioned steering column 15, utilize supporting bracket 24 that the intermediate portion is bearing in before coaming plate following wait on the part of vehicle body 26.In addition, between this supporting bracket 24 and vehicle body 26, not shown fixing part is set, under the situation of the impact of the direction that applies directed forward on this supporting bracket 24, this supporting bracket 24 comes off from said fixing portion.In addition, the upper end portion of said gear case 22 also is bearing on the part of above-mentioned vehicle body 26.In addition, by leaning device being set and the mirror mechanism of looking in the distance, can freely regulate the front and back position and the height and position of aforementioned steering wheel 1.This leaning device and the mirror mechanism of looking in the distance are known in the art, and are not the characteristics of present embodiment, so omit its detailed description.
In addition, the front end of axle 20 in above-mentioned from the outstanding part of the front-end face of said gear case 22, via universal joint 7, is attached on the rearward end of jack shaft 8.In addition, the input shaft 10 with steering gear mechanism 9 is attached on the front end of this jack shaft 8 via other universal joint 7.Aforementioned small gear 11 is attached on this input shaft 10.In addition, aforementioned tooth bar 12 is engaged on this small gear 11.In addition, in order to prevent from ground to be applied to vibration transfer on the jack shaft 8 to steering wheel 1, also can on above-mentioned each universal joint 7, shock arrester (-tor) be set via wheel.
In addition, aforementioned worm speed reducer 16 comprises: can free outer build-in fix on above-mentioned in worm gear 28 on spools 18 the part, worm shaft 29 is turned round helical spring 30, preload pad 70.And then above-mentioned worm speed reducer 16 comprises being respectively first of single-row shallow/deep groove type～the 4th ball bearing 34～37.
In addition, aforementioned torque sensor 3, be arranged on aforementioned steering shaft 2 intermediate portion around, detect the direction and the size that are applied to the torque of this steering shaft 2 from aforementioned steering wheel 1, with the expression checkout value signal (testing signal) be sent to aforementioned controller 6.Then, this controller 6 according to this testing signal, is sent the signal that drives usefulness to aforementioned motor, along the size generation assist torque of prescribed direction with regulation.
In addition, above-mentioned worm gear 28 and worm shaft 29 are arranged on the inboard of said gear case 22, make worm screw 27 engagements of this worm gear 28 and the intermediate portion that is arranged on this worm shaft 29.In addition, above-mentioned motor 31, comprise: in conjunction with the shell 23 that is fixed on this gear-box 22, be arranged on and decide to give 39 by what permanent magnet was made on the inner peripheral surface of this shell 23, be arranged on the running shaft 32 of the inboard of this shell 23, the rotor 38 that is provided with state at the intermediate portion of this running shaft 32 with these stator 39 subtends.
In addition, aforementioned first ball bearing 34, be arranged between the base end part outer circumferential face of the inner peripheral surface of shrinkage pool 41 of the central part of being located at the base plate 40 that constitutes above-mentioned shell 23 and above-mentioned running shaft 32, with respect to above-mentioned shell 23, but the base end part of this running shaft 32 of free rotary ground supporting (Fig. 2,3 left part).In addition, aforementioned second ball bearing 35, be arranged between the intermediate portion outer circumferential face of the inner circumference edge of the spacing wall 42 on the intermediate portion inner peripheral surface of being located at above-mentioned shell 23 and above-mentioned running shaft 32, can be with respect to the intermediate portion of this this running shaft 32 of spacing wall 42 free rotary ground supportings.In addition, above-mentioned rotor 38 constitutes on the slit 44 at a plurality of positions of the circumferencial direction of the outer circumferential face by coil 45 being wound up into the iron core 43 that is arranged on lamination steel plate system, and wherein, described unshakable in one's determination 43 are arranged on the intermediate portion of this running shaft 32.In addition, locating, on the part between above-mentioned rotor 38 and the above-mentioned spacing wall 42, the transducer 46 of the usefulness of switching on is set on above-mentioned coil 45 near the part of the front end of above-mentioned running shaft 32 (Fig. 2,3 right end portion).
On the other hand, brush carrier 47 is fixed on the inner peripheral surface of above-mentioned shell 23 and the parts these transducer 46 subtends.And, in this brush carrier 47, can collect brush 48 with displacement in the radial direction freedom of above-mentioned shell 23.This brush 48 is with the terminal conducting of not shown connector on the outer circumferential face of this shell 23 that is provided with.In addition, utilize the spring 49 that is bearing in the above-mentioned brush carrier 47, give the elastic force that above-mentioned brush 48 points to the internal side diameter of above-mentioned shell 23.Thereby the interior edge face of this brush 48 contacts with the outer circumferential face elasticity sliding motion of above-mentioned transducer 46.And, utilize this transducer 46 and above-mentioned brush 48, the rotor phase detector that the direction of the field current of the above-mentioned coil 45 of formation switch current direction is used.
And then, utilize spline fitted portion 33 that the end of above-mentioned two axles 29,32 is connected to each other, wherein, spline fitted portion 33, be by the cloudy spline part 50 on the inner peripheral surface that makes the base end part that is arranged on aforementioned worm shaft 29 (Fig. 2,4 left part), carry out with the positive spline part 51 of the front end that is arranged on aforementioned running shaft 32 that spline fitted constitutes.By this structure, worm shaft 29 and running shaft 32 rotate together.
In addition, aforementioned the 3rd ball bearing 36, can rotate freely the base end part of above-mentioned worm shaft 29 is bearing in the inboard of aforesaid gears case 22.For this reason, will constitute the outer shroud 57 of the 3rd ball bearing 36, on the embedded inner peripheral surface that is fixed to the bearing hole 59 on the part of being located at aforesaid gears case 22.In addition, make an end face (Fig. 2,4 right side) of the axial direction of this outer shroud 57, run into the end difference 58 on the inner peripheral surface that is arranged on this bearing hole 59, simultaneously, utilization is fixed to the retaining ring 88 on this inner peripheral surface, suppresses another end face (Fig. 2,4 left side) of the axial direction of above-mentioned outer shroud 57.In addition, will constitute the interior ring 52 of above-mentioned the 3rd ball bearing 36, on outer circumferential face,, be embedded into outward on the part consistent with above-mentioned spline fitted portion 33 with respect to axial direction near the cardinal extremity part of above-mentioned worm shaft 29.And, make the middle position of axial direction of this spline fitted portion 33 consistent basically with the axial direction middle position of the 3rd ball bearing 36.In addition, between the outer circumferential face by ring 52 inner peripheral surface in above-mentioned and above-mentioned worm shaft 29 small gap is set, can be with above-mentioned worm shaft 29 within the limits prescribed with respect to 36 inclinations of above-mentioned the 3rd ball bearing.In addition, two end faces of ring 52 axial direction and screw thread are fixed between the interior edge face of the nut 55 on the external screw thread 54 in above-mentioned, a plurality of butterfly springs 56 respectively are set respectively, wherein external screw thread 54, are arranged on the base end part of being located near the side of the lip part 53 on the outer circumferential face of the cardinal extremity of this worm shaft 29 part and this worm shaft 29.And, ring 52 in above-mentioned flexibly is clamped between the side of above-mentioned lip part 53 and the interior edge face of nut 55 (Fig. 2,4 left side).By this structure, can make above-mentioned worm shaft 29 in the predetermined range of axial direction, carry out elastic displacement with respect to above-mentioned the 3rd ball bearing 36.In addition, preferably,, use the ball bearing of 4 point-contact types as above-mentioned the 3rd ball bearing 36.
On the other hand, aforementioned the 4th ball bearing 37, can rotate freely the front end of above-mentioned worm shaft 29 (Fig. 2,4,5 right part) is bearing in the inboard of said gear case 22.For this reason, the outer shroud 60 that constitutes above-mentioned the 4th ball bearing 37 is fixed on the retainer 61 of the inboard of being fixed in said gear case 22.This retainer 61, its cross section are L shaped, whole form circularly it, and above-mentioned outer shroud 60 is embedded to be fixed on the large-diameter portion 62 on the inner peripheral surface of one and half ones that are arranged on this retainer 61 (Fig. 2,4,5 left side).In addition, on outer circumferential face near the fore-end of above-mentioned worm shaft 29, lining 64 outer being embedded on the large-diameter portion 63 that are arranged on the part that breaks away from aforementioned worm screw 27 that elastic material is made.This lining 64, its cross section are L shaped, and its whole formation is cylindric.And, the large-diameter portion 63 of above-mentioned worm shaft 29 is loosely inserted the inboard that penetrates into this lining 64, simultaneously, make the front end of above-mentioned worm shaft 29 outstanding from an end face of the axial direction of this lining 64 (Fig. 2,4,5 right side).And, the interior ring 65 outer embeddings that constitute above-mentioned the 4th ball bearing 37 are fixed on the intermediate portion of axial direction of above-mentioned lining 64.In addition, an end face of the axial direction by making in this ring 65 (Fig. 2,4,5 left side) is run into the inner side surface of the export-oriented lip part 67 on another end (Fig. 2,4,5 left part) of the axial direction that is arranged on above-mentioned lining 64, so that carry out the location of the axial direction of ring 65 in this.And,, can make above-mentioned worm shaft 29 with respect to this lining 64 tilt within the limits prescribed (displacement of radial direction) by little gap slightly is set between the outer circumferential face of the inner peripheral surface of above-mentioned lining 64 and above-mentioned large-diameter portion 63.
In addition, between being arranged on the large-diameter portion 63 on this worm shaft 29 and being arranged on, the conical surface 89 is set than the minor diameter on the part of this large-diameter portion 63 more close forward end 68.In addition, in the continuous portion of this minor diameter 68 and the front-end face of above-mentioned worm shaft 29, the conical surface 109 is set.And, above-mentioned minor diameter 68 is not inserted in the part of preload pad 70 with rocking, described preload pad is configured in another end face (Fig. 2,4,5 right side) of the retainer 61 on the aforesaid gears case 22 and is arranged between the bottom surface of the shrinkage pool 72 on this gear-box 22.This preload pad 70, as Fig. 7～9 were at length represented, the grade of the synthetic resin injection molded by will sneaking into solid lubricant was made the shape of removing near the one-sided part of two positions of the opposition side of the radial direction of the outer peripheral portion that lacks round tube.In addition, in the planar surface portion 91 of the radially opposition side of the outer circumferential face of being located at this preload pad 70, on, arm 92 is set near the one-sided part of the end (underparts of Fig. 7～9) of length direction (Fig. 7～9 near inboard parts).In addition, with the minor diameter 68 of above-mentioned worm shaft 29, can freely not be inserted into the inboard of through hole 71, described through hole 71 is with the state setting of the central part of the width direction (left and right directions of Fig. 6～9) that in axial direction connects this preload pad 70 with rocking.
In addition, on part, the conical surface 93a, the 93b that become big more the closer to the opening end diameter are set respectively near the two ends of the axial direction of above-mentioned through hole 71.In addition, with the sectional shape of the inner peripheral surface of axial direction intermediate portion under free state of this through hole 71, make and be roughly equilateral triangle, make two line part shapes connected to one another that adjoin each other with curve part respectively.And, with equally spaced 3 positions of the circumferencial direction of the intermediate portion inner peripheral surface of residing locational, the above-mentioned through hole 71 of the intermediate portion of described each line part, as the contacting part 94 of the outer circumferential face Elastic Contact of the minor diameter 68 of above-mentioned worm shaft 29.Under the situation of present embodiment, described each contacting part 94 for the central shaft that comprises above-mentioned preload pad 70, the imaginary plane α (Fig. 7) of central part by width direction, is on the position of symmetry.In addition, on the inner peripheral surface of the intermediate portion of the axial direction of above-mentioned through hole 71,, be on the part of opposition side, form recess 95 with a contacting part 94 of the width direction central part that is positioned at above-mentioned preload pad 70 for the central shaft of this through hole 71.By this structure, on the part of the circumferencial direction of above-mentioned preload pad 70, reduce corresponding to the rigidity of the part of this recess 95, this part is carried out resiliently deformable easily.In addition, inside and outside two side faces that make above-mentioned preload pad 70 are communicated with each other discontinuous 90, be arranged on for above-mentioned imaginary plane α, to the position of a side (right sides of Fig. 7～9) skew.
On the other hand, on the outer circumferential face of above-mentioned preload pad 70, with the part of the opposition side (downsides of Fig. 7～9) of aforementioned worm gear 28 on, first portion's cylinder face 104 is set, on the part of these worm gear 28 sides (the s upsides of Fig. 7～9), be provided with and second portion cylinder face 105 that this first cylinder facial 104 is concentric.In addition, on the intermediate portion of the circumferencial direction of this first portion's cylinder face 104, the little protuberance of width 106 is set, simultaneously, with the front-end face of this protuberance 106, as the third part barrel surface face 107 concentric with this first portion's cylinder facial 104.In addition, on the outer circumferential face of above-mentioned preload pad 70, with above-mentioned worm gear 28 opposition sides part, with the end (right part of Fig. 5, the surface side end of Fig. 7～9) of the axial direction of aforementioned retainer 61 opposition sides on, the fixed salient 108 that is projected into outside diameter is set.
This preload pad 70 according to the mode shown in Fig. 8,9, is combined on the free embedded aforementioned retainer 61 that is fixed on the aforesaid gears case 22 (Fig. 2,4～6).In addition, on another face (face of the surface side of Fig. 9) of the axial direction of this retainer 61, separately on 4 positions of the open circumferential portion of above-mentioned through hole 96, each forms two, amounts to 4 first, second protuberances 97,98.Wherein each first protuberance 97 is present in worm gear 28 sides (Fig. 2,4,5 upside), and each second protuberance 98 is present in the opposition side (Fig. 2,4,5 upper and lower sides) of this worm gear 28.In addition, on the side of the outside diameter of above-mentioned each first, second protuberance 97,98, part cylinder face 99 is set with one heart mutually respectively.In addition, near the fore-end of described each second protuberance 98, with the side of above-mentioned worm gear 28 opposition sides on, first fixed salient 100 is set.
And retainer 61 and 70 combinations of preload pad with constituting as mentioned above respectively simultaneously, around described two members 61,70, are provided with and are turned round helical spring 30.Promptly, above-mentioned preload pad 70 is configured in the inboard of each first one of being located on this retainer 61, second protuberance 97,98, simultaneously, the side that each arm 92 on this preload pad 70 is fixed to described each second protuberance 98 (Fig. 8,9 downside) will be arranged on.In addition, make a side being arranged on first fixed salient 100 on above-mentioned each second protuberance 98 (Fig. 8,9 inboard face) and above-mentioned each arm 92, via small gap subtend.In addition, in above-mentioned two ends being turned round helical spring 30,2 locational a pair of fixing parts 73 that one side will be arranged on the radial direction opposition side are configured on the part in the middle of first, second protuberance 97,98 that adjoins each other on the part of being located at above-mentioned retainer 61, and the main body (spiral part) that one side will above-mentionedly be turned round helical spring 30 is embedded in outward on the outer circumferential face of the side of outside diameter of first, second protuberance 97,98 and above-mentioned preload pad 70.In addition, with this fixing part 73 of being turned round helical spring 30, be fixed on another side of being located at each second protuberance 98 on the above-mentioned retainer 61 (Fig. 6,8,9 upper side).In addition, utilize second fixed protrusion 101 on the front end of another side be arranged on described each second protuberance 98, prevent getting loose of above-mentioned each fixing part 73.And, with the above-mentioned inner circumference edge of being turned round the main body of helical spring 30, flexibly be pressed to be arranged on aforementioned worm gear 28 opposition sides (Fig. 2,4～9 downside) on third part cylinder face 107 on.
In addition, under the situation of present embodiment,, make each planar surface portion 91 and the side subtend that is arranged on the internal side diameter of each first, second protuberance 97,98 on the above-mentioned retainer 61 of being arranged on the above-mentioned preload pad 70 via small gap.According to this structure,, limit of the displacement of above-mentioned preload pad 70 with respect to the width direction of this preload pad 70 (Fig. 2,4,5 surface and the inside direction) by these internal side diameter sides.Under the situation of present embodiment, the internal side diameter side of above-mentioned each the one the second protuberance 97,98 is equivalent to guide surface.
And, like this, with retainer 61 and preload pad 70 and turned round under the state that helical spring 30 combines, on the embedded part that is fixed to aforesaid gears case 22 of this retainer 61.In addition, with this retainer 61 embedded be fixed on the aforesaid gears case 22 after, the minor diameter 68 that is arranged on the front end of aforementioned worm shaft 29 is inserted in the through hole 71 that is arranged on the above-mentioned preload pad 70.According to this structure,,, give the direction of pointing to aforementioned front-wheel 28 (Fig. 2,4,5 the direction that makes progress) elastic force from above-mentioned front end from helical spring 30 to above-mentioned worm shaft 29 that turned round via above-mentioned preload pad 70.That is, be inserted under the state before the through hole 71 that is arranged on this preload pad 70 central shaft of this through hole 71, amesiality for the central shaft of above-mentioned retainer 61 (upsides of Fig. 4～9) at front end with above-mentioned worm shaft 29.And, when the front end of above-mentioned worm shaft 29 being inserted into the through hole 71 that is arranged on the above-mentioned preload pad 70 inboard,, the above-mentioned diameter of being turned round helical spring 30 is flexibly expanded by the third part cylinder face 107 that is arranged on this preload pad 70.And, become the tendency of being turned round helical spring 30 to this to the direction elastic reset of wraparound (diameter reduction), turned round helical spring 30 from this, on the front end of above-mentioned worm shaft 29, given the elastic force of the direction of pointing to above-mentioned worm gear 28 via above-mentioned preload pad 70.According to this structure, outer embedding is fixed to aforementioned interior 18 and the central shaft distance each other of above-mentioned worm shaft 29 on this worm gear 28, elastic shrinkage.Consequently, the worm screw 27 of above-mentioned worm shaft 29 and the flank of tooth of above-mentioned worm gear 28 contact with the state of giving preload each other.
And then, by based on the above-mentioned elastic force of being turned round helical spring 30, the front end of above-mentioned worm shaft 29 in the inboard of being located at the through hole 71 on the above-mentioned preload pad 70 to aforementioned recess 95 side displacements, this preload pad 70 is own, as shown in Figure 6, with the mode at the two side portions interval each other of the above-mentioned recess 95 in expansion clamping this preload pad 70, resiliently deformable.And, each planar surface portion 91 of above-mentioned each preload pad 70 flexibly is expanded into the Ha font, described each planar surface portion 91 contacts with the internal side diameter side elastic of each first, second protuberance 97,98 on being located at aforementioned retainer 61, and the gap of described each planar surface portion 91 and internal side diameter side dwindles.
In addition, under the situation of present embodiment, with the outer circumferential face and the above-mentioned contacting part part of being turned round the inner circumference edge of helical spring 30 of above-mentioned preload pad 70, make the circular-arc of part, simultaneously, make the length of this contacting part, enough little with respect to this length of enclosing of being turned round helical spring 30.In addition, around above-mentioned preload pad 70, be provided with under this state of being turned round helical spring 30, between the surface of the surface of the wire rod parts that constitute this each circle of the being turned round helical spring 30 other wire rod parts adjacent (between the line), the gap of axial direction is set with described each wire rod parts.
As mentioned above, at the worm speed reducer of present embodiment and be equipped with under the situation of electric type power steering device of this retarder, utilize and turned round helical spring 30, on worm shaft 29, give the elastic force of the direction of pointing to worm gear 28 via preload pad 70.Therefore, can utilize cheap structure, the engaging piece of giving described worm gear 28 and worm shaft 29 can be suppressed at the generation that this engaging piece is beaten dental with preload.And, under the present embodiment situation, utilize the internal side diameter side of being located at first, second each protuberance 97,98 on the retainer 61 that is fixed on the gear-box 22, limit of the displacement of above-mentioned preload pad 70 with respect to width direction.In addition, based on the above-mentioned elastic force that is subjected to helical spring 30, the front end that makes above-mentioned worm shaft 29 to recess 95 side displacements, makes this preload pad 70 resiliently deformables own in the inboard of being located at the through hole on the preload pad 70.And, contact with the internal side diameter side elastic by each planar surface portion 91 that makes this preload pad 70, dwindle the gap between described each planar surface portion 91 and the internal side diameter side.Thereby, when motor 31 (Fig. 1～4) drives, although apply direction reaction force shown in 7 arrow イ, ロ to above-mentioned worm shaft 29 from the above-mentioned worm gear 28, but, can prevent that preload pad 70 from colliding above-mentioned each first, second protuberance 97,98 tempestuously, can suppress ear-piercing abnormal sound (noise).In addition, can not undermine above-mentioned inhibition effect of beating dental owing to the generation that suppresses this abnormal sound.
In addition, under the situation of present embodiment, because above-mentioned preload pad 70 usefulness synthetic resin are made, so, when being inserted into the through hole 71 be located on this preload pad 70 inboard in end with above-mentioned worm shaft 29, can make this preload pad 70 that resiliently deformable takes place easily, carry out this insertion operation easily.In addition, surface at the surface of the wire rod parts that constitute an above-mentioned circle of the being turned round helical spring 30 other wire rod parts adjacent with described each wire rod parts contact along axial direction under the situation of (spring of tight coiling), rub at this contacting part, become and utilize the above-mentioned helical spring 30 of being turned round to give the reason that the elastic force of above-mentioned worm shaft 29 changes irrelevantly.Relative therewith, under the situation of present embodiment, because each other on the surface of the surface of wire rod parts of above-mentioned each circle other wire rod parts adjacent with described each wire rod parts, the gap (being turned round helical spring 30 is not the spring of closely reeling) of axial direction is set, so, can more stably give the elastic force of above-mentioned worm shaft 29 with regulation.
In addition, under the situation of present embodiment, since the end of above-mentioned preload pad 70 outer circumferential face on, setting is projected into the fixed salient 108 of outside diameter, so, can prevent to be turned round spiral elasticity 30 and come off, simultaneously, can limit this and be turned round the displacement of helical spring 30 with respect to preload pad 70 axial directions from the periphery of this preload pad 70.
Embodiment 2
Secondly, Figure 10 represents embodiments of the invention 2.Under the situation of present embodiment, make the position of inner peripheral surface with the contacting part 94a of the outer circumferential face of the minor diameter 68 of the front end that is arranged on worm shaft 29 of the through hole 71a that is arranged on the preload pad 70, different with the situation of above-mentioned first example.Promptly, under the situation of present embodiment, the contacting part 94a of above-mentioned worm shaft 29 and preload pad 70 is arranged on equally spaced 3 positions of circumferencial direction with respect to the direction symmetry of the arrow イ of Figure 10, the direction of described arrow イ be from worm gear 28 (with reference to as 4～5) be applied to reaction force on this worm shaft 29 have the tendency that becomes big, this worm gear 28 to the direction sense of rotation of regulation, with respect to the direction of the above-mentioned reaction force of the direction of the orthogonality of center shaft of this worm shaft 29.
Under the situation of this present embodiment, when motor 31 (with reference to Fig. 1～3) drives, under the situation of the reaction force of the direction that applies above-mentioned arrow イ from above-mentioned worm gear 28 to above-mentioned worm shaft, both sides with respect to the direction of this arrow イ can be easy to make equably basically above-mentioned preload pad 70 to carry out big resiliently deformable.Therefore, even in each planar surface portion 91 of this preload pad 70 and be arranged between the side of internal side diameter of first, second each protuberance 97,98 (with reference to Fig. 6,8,9) on the retainer 61 and exist under the situation in gap, also can strengthen the elastic deformation amount of above-mentioned preload pad 70, can prevent above-mentioned preload pad 70 because the reaction force that is applied on the above-mentioned worm shaft 29 produces big displacement to above-mentioned arrow イ side.Thereby, prevent that the part of this preload pad 70 from colliding the internal side diameter side of above-mentioned first, second each protuberance 97,98 tempestuously, can relax from this preload pad 70 and be applied to impact force on the internal side diameter side, can more effectively suppress because the abnormal sound that these preload pad 70 these internal side diameter sides of collision cause.About other structure and effect and since with the situation of the foregoing description 1 under identical, so, give identical label for equal part, the repetitive description thereof will be omitted.
Embodiment 3
Secondly, Figure 11～12 expression embodiments of the invention 3.Under the situation of present embodiment,, separate two element 110a, 110b constitute preload pad 70a by being combined.Described two element 110a, 110b, discontinuous 90 of preload pad 70 of the structure of the embodiment 1 shown in the earlier figures 1～9 will be constituted, be arranged on the central part of width direction, simultaneously, have and for the central shaft of through hole 71 (with reference to Fig. 7 etc.) with on this discontinuous 90 opposite position, this preload pad 70 is being cut off the shape that is obtained.Promptly, above-mentioned each element 110a, 110b at the mutual intermediate portion of the length direction (above-below directions of Figure 11～12) of a side of subtend, are provided with and are roughly the planar recess of semicircular cylinder 111, on part, planar surface portion 112a, 112b are set near the two ends of this length direction.In addition, on another side of the mutual opposition side of described these elements 110a, 110b, planar surface portion 91 and arm 92 are set respectively.And, under the state that planar surface portion 112a, 112b dock each other, one side combines described each element 110a, 110b that simultaneously will be arranged on above-mentioned each side, by making above-mentioned each recess 111 opposite to one another, form and be arranged on the through hole that the through hole 71 on the preload pad 70 of the structure that constitutes previous embodiment 1 has same shape.
In addition, on the outer circumferential face of above-mentioned each element 110a, 110b, with the part of worm gear 28 (with reference to Fig. 2,4,5) opposition side (Figure 11,12 downside) on, the facial 104a of first portion's cylinder is set, on the part of above-mentioned worm gear 28 sides (Figure 11,12 upside), the circular-arc second portion cylinder face 105a concentric with the facial 104a of first cylinder is set.In addition, in the facial 104a of above-mentioned each first portion cylinder, on an end of the width direction of subtend mutually, the little protuberance 106a of width is set, with the front-end face of described each protuberance 106a, as the third part cylinder facial 107a concentric with the facial 104a of above-mentioned each first portion's cylinder.In addition, on the outer circumferential face of above-mentioned each element 110a, 110b, with above-mentioned worm gear 28 opposition sides part, with an end of the axial direction of retainer 61 opposition sides (Figure 11,12 surface side end) on, the fixed salient 108a that is projected into outside diameter is set.
And, a pair of element 110a, 110b and the above-mentioned retainer 61 that constitutes as mentioned above respectively combined, simultaneously, described each member 110a, 110b, 61 around, be provided with and turned round helical spring 30.Promptly, above-mentioned a pair of element 110a, 110b are configured in the inboard of being located at each first, second protuberance 97,98 on the above-mentioned retainer 61, simultaneously, with the arm 92 that is arranged on above-mentioned each element 110a, 110b, be fixed to a side (downside of Figure 12) of described each second protuberance 98.In addition, via small gap, make the side (the inboard face of Figure 12) and above-mentioned each arm 92 subtend that are arranged on first fixed salient 100 on described each second protuberance 98.
In addition, in above-mentioned two ends being turned round helical spring 30, under the locational a pair of fixing part 73 at two positions will being located at the radial direction opposition side is configured in state on the part between first, second protuberance 97,98 that adjoins each other of being located on the above-mentioned retainer 61, the above-mentioned main body of being turned round helical spring 30 is embedded into outward on the outer circumferential face of the outside diameter side of described each first, second protuberance 97,98 and above-mentioned each element 110a, 110b.In addition, the fixing part 73 of this being turned round helical spring 30 is fixed on another side (upper side of Figure 12) of being located at each second protuberance 98 on the above-mentioned retainer 61.And,, flexibly be pressed on the facial 107a of the third part cylinder of being located on above-mentioned each element 110a, the 110b the above-mentioned inner circumference edge of being turned round the main body of helical spring 30.
In addition, under the situation of present embodiment, make the planar surface portion of being located on above-mentioned each element 110a, the 110b 91, via small gap and the internal side diameter side subtend of being located at each first, second protuberance 97,98 on the above-mentioned retainer 61.By this structure, above-mentioned each element 110a, 110b utilize their internal side diameter side, limit described each element 110a, the 110b displacement with respect to width direction (Figure 11,12 left and right directions).
And, like this with retainer 61 and each element 110a, 110b and turned round under the state that helical spring 30 combines, on the embedded part that is fixed to gear-box 22 (with reference to Fig. 1,2 etc.) of this retainer 61.In addition, after being fixed to above-mentioned retainer 61 on the said gear case 22, the minor diameter of being located on the front end of worm shaft 29 68 (with reference to Fig. 4～7) is inserted in the through hole that recess 111 combinations with one another of above-mentioned each element 110a, 110b are got up to constitute.By this structure, turned round helical spring 30 is given the direction of pointing to above-mentioned worm gear 28 to the front end of above-mentioned worm shaft 29 via above-mentioned each element 110a, 110b elastic force from above-mentioned.And the flank of tooth of the worm screw 27 of above-mentioned worm shaft 29 (with reference to Fig. 2,4,5) and this worm gear 28 contacts giving under the state of preload each other.
And then, by by the above-mentioned elastic force of being turned round helical spring 30, the front end of above-mentioned worm shaft 29 is in the interior side direction of above-mentioned through hole 71 and the opposition side displacement of above-mentioned worm gear 28, is located at the planar surface portion 91 on another side of above-mentioned each element 110a, 110b, flexibly is extended to Ha shape.And, by described each planar surface portion 91 flexibly with the internal side diameter contacts side surfaces that is arranged on each first, second protuberance 97,98 on the aforementioned retainer 61, dwindle the gap of described each planar surface portion 91 and internal side diameter side.
Under the situation of the present embodiment that constitutes as mentioned above, when motor 31 (with reference to Fig. 1～3) drives, although apply reaction force to above-mentioned worm shaft 29 from above-mentioned worm gear 28, but, the internal side diameter side that above-mentioned each element 110a, 110b collide above-mentioned each first, second protuberance 97,98 tempestuously can be prevented, ear-piercing abnormal sound (noise) can be suppressed.About other structure and effect, since same with the incision of the embodiment 1 shown in the earlier figures 1～9, so give identical label, omit the explanation of its repetition for equal part.
Embodiment 4
Secondly, Figure 13～14 expression embodiments of the invention 4.Under the situation of present embodiment, make retainer 61 and preload pad 70 and turned round the direction that is provided with of helical spring 30, under the embodiment of institute shown in the earlier figures 1～9 1 the situation, skew is equivalent to the angle θ of Figure 13.Promptly, make as preload pad 70 can along the direction of the internal side diameter side displacement of being located at each first, second protuberance 97,98 on this retainer 61, the direction shown in the arrow Ha among Figure 13, with respect to central shaft that comprises worm shaft 29 and the imaginary plane α that is arranged on the engaging piece of the worm and wheel 28 (with reference to Fig. 2,4,5) on this worm shaft 29, an angle θ tilts.In addition, under the situation of present embodiment, make the angle beta that the direction shown in the arrow Ha constitutes in the direction shown in arrow イ, the ロ and Figure 13 among Figure 13 1, β 2Basically equate (β 1 β 2), wherein, direction shown in arrow イ, the ロ is a direction different because of the sense of rotation of this worm gear 28, be applied to the reaction force on the above-mentioned worm shaft 29 from this worm gear 28 when utilizing motor 31 (with reference to Fig. 1～3) to drive, direction shown in the arrow Ha is the direction of displacement of preload pad 70 along the internal side diameter side of above-mentioned each first, second protuberance 97,98.In other words, by as preload pad 70 along the direction direction of the internal side diameter side displacement of above-mentioned each first, second protuberance 97,98, shown in the above-mentioned arrow Ha, the angle γ (Figure 13) that the direction shown in above-mentioned arrow イ, the ロ is constituted each other halves basically.
Under the situation of the present embodiment that constitutes as mentioned above, when utilizing motor 31 to drive, can be easy to dwindle the difference that difference caused of the elastic deformation amount of the above-mentioned preload pad 70 that causes owing to the reaction force that is applied to direction shown in arrow イ on the above-mentioned worm shaft, Figure 13, the ロ from above-mentioned worm gear 28 because of this direction.Therefore, even in each planar surface portion 91 of this preload pad 70 and be arranged between the internal side diameter side of first, second each protuberance 97,98 on the retainer 61 and exist under the gapped situation, the difference of the impact force in the time of also can being easy to dwindle above-mentioned preload pad 70 these internal side diameter sides of collision that the difference because of above-mentioned direction causes.About other structure and effect, because the same with the situation of the embodiment 1 shown in above-mentioned Fig. 1～9, so, give same label for identical part, omit its repeat specification.
In addition, though omit among the figure, but it is different with the situation of present embodiment, in the embodiment shown in the earlier figures 1～9 1 structure, under the identical situation of the driving force of supposition motor 31, by the size that is applied to the reaction force on the worm shaft 29 from worm gear 28 is equated basically with the orientation independent of this reaction force, also can dwindle because the difference that the elastic deformation amount of the preload pad 70 that this reaction force causes causes because of the direction difference of this reaction force.In addition, adopting under the situation of this structure, the direction of these reaction forces (direction shown in arrow イ, the ロ among Fig. 7), equating basically with the central shaft that comprises worm shaft 29 and the angle of imaginary plane α (Fig. 7) formation of being located at the engaging piece of the worm and wheel 28 on this worm shaft 29.Therefore, different with the situation of the embodiment 4 shown in above-mentioned Figure 13,14, there is no need to make preload pad 70 to tilt with respect to central shaft that links above-mentioned worm shaft 29 and above-mentioned engaging piece imaginary plane α along the direction of the internal side diameter side displacement that is arranged on first, second each protuberance 97,98 on the retainer 61.For example, under the situation shown in aforementioned Figure 47,48, if with the oscillation center o of this engaging piece and worm shaft 29 along the radial direction of this worm shaft 29 apart from d 29Distance L with this engaging piece and this oscillation center o along axial direction 29Ratio d 29/ L 29Narrow down to enough for a short time, can get the size reduction of Fr enough little.Therefore, with the orientation independent of the reaction force that applies to worm shaft 29 from worm gear 28, the size of these reaction forces is equated basically.Thereby, in the embodiment shown in the earlier figures 1～9 1 structure, orientation independent with the reaction force that applies to worm shaft 29 from worm gear 28, size by making these reaction forces equates basically, can dwindle the difference that the impact force on the internal side diameter side of preload pad 70 first, second each protuberances 97,98 of collision causes because of the difference of the direction of these reaction forces.Conversely speaking, by adopting above-mentioned structure shown in Figure 13, even shorten size, the above-mentioned ratio d of increase of the axial direction of above-mentioned worm shaft 29 for miniaturization 29/ L 29, also can with the orientation independent of reaction force, carry out the mitigation of above-mentioned impact force effectively.
In addition, under above-mentioned each embodiment's situation, make small gear 11 and directly engagement of tooth bar 12 (with reference to Figure 46) on the end that is fixed to pinion shaft 10 (with reference to Fig. 1,46), still, the present invention is not limited to this structure.For example, also can will the structure of so-called speed of a motor vehicle servo-actuated optional gear ratio mechanism (VGS) and the textural association of present embodiment be housed, wherein said speed of a motor vehicle servo-actuated optional gear ratio mechanism (VGS), the pin that is arranged on the underpart of pinion shaft can be engaged in along the length direction freedom of this slotted hole in the slotted hole of the small gear that is arranged with this pinion shaft branch with displacement, simultaneously, make the engagement of this small gear and tooth bar, make of the ratio variation of the displacement amount of tooth bar according to the speed of a motor vehicle with respect to the angle of swing of steering shaft.
In addition, the present invention, be not limited to motor be arranged on steering shaft 2 around structure.For example, as shown in figure 15, also can make the structure that motor 31 is arranged on the periphery of the small gear 11 (with reference to Figure 46) that meshes with tooth bar 12.And, under the situation of this structure shown in Figure 15, will constitute the worm gear of worm speed reducer 16, be fixed to above-mentioned small gear 11 or be bearing on the part of the member on this small gear 11.Under the situation of this structure shown in Figure 15, also can torque sensor 3 (with reference to Figure 46) be arranged on steering shaft 2 around, and be arranged on the periphery of above-mentioned small gear 11.
In addition, as shown in figure 16, also can be in the part of gear 12, motor 31 is arranged at the periphery that is engaged to secondary small gear 75 on the position of leaving with the auxiliary section of small gear 11.Under the situation of this structure shown in Figure 16, make the worm gear and worm shaft 29 engagements that are fixed on this pair small gear 75.Under this structure situation shown in Figure 16, also torque sensor 3 (with reference to Figure 46) can be arranged on the periphery of above-mentioned small gear 11.In addition, under the situation of structure shown in Figure 16, damping device 76 is set, is used to prevent be delivered on the steering wheel 1 passing to the vibration of above-mentioned small gear 11 via wheel by ground at the intermediate portion of jack shaft 8.For example, this damping device 76 is combined into interior axle and outer shaft and looks in the distance specularly, constitutes each other by the end side face that elastic material is attached to described two axles.
Like this, each auxiliary axis of the invention described above can be steering shaft, small gear, be engaged to any one member in the secondary small gear on the tooth bar etc. in the position of leaving this small gear.
In addition, under above-mentioned each embodiment's situation, utilize brush 48 and transducer 46 (with reference to Fig. 2,3) to constitute the rotor phase detector that the direction of the field current that is sent to the coil 45 that constitutes motor 31 is switched usefulness.But the present invention is not limited to this structure, also can utilize the permanent magnetism encoder 78 made of iron and the Hall integrated circuit 77 that are fixed on the running shaft 32 to constitute the rotor phase detector as shown in figure 17, and motor 31 is made so-called brushless structure.In addition, under the situation of structure shown in Figure 17, the coil 83 that utilization is fixed to the iron core 82 of the lamination steel plate system on the inner peripheral surface of shell 23 and is wound up into a plurality of positions of this iron core 82 constitutes stator 39a, simultaneously, utilize the permanent magnet 84 on the intermediate portion outer circumferential face that is fixed on above-mentioned running shaft 32 to constitute rotor 38a.In addition, under the situation that adopts this structure, also can switch the magnetic force of this stator 39a by the vector control apparatus of the increase and decrease of controlling the size of current that is sent to said stator 39a is set.
In addition, under above-mentioned each embodiment's situation, be illustrated for the situation that worm speed reducer is encased in the electric type power steering device.But worm speed reducer of the present invention is not limited to be used for this purposes, also can be encased in the electric linear actuator in the various mechanical devices such as being installed in beddo, electronic desk, electronic chair, lift to use.For example, under the situation in worm speed reducer being encased in this electric linear actuator, after with of the rotational delay of this worm speed reducer with motor, extract on the running shaft, via ball screw etc. make be arranged on this running shaft around output shaft flexible.The present invention also goes for this worm speed reducer that is encased in the electric linear actuator.
Worm speed reducer of the present invention and electric type power steering device, owing to constituting by above-described mode and working, so, in order to be suppressed at the generation of beating dental on the worm speed reducer, the worm shaft that the constitutes worm speed reducer structure with elastic force is given in utilization by resilient member and via other member, can suppress the generation of the unusual sound that the collision of this other member and the part of the displacement that limits this other member causes.
Embodiment 5
Figure 18～24 expression embodiments of the invention 5.The electric type power steering device of present embodiment, comprise: steering wheel 1 is fixed to steering shaft 2 on the rearward end, can freely insert the steering column 15 that connects this steering shaft 2, give the worm speed reducer 16a that this steering shaft 2 is used with assist torque, be arranged on the small gear 11 (with reference to Figure 46) of the forward end of this steering shaft 2, with this small gear or be bearing in the secondary small gear 12 (with reference to Figure 46) of the member engagement on this small gear, torque sensor 3 (with reference to Figure 46), motor 31, controller 6 (with reference to Figure 46).
Steering shaft 2 is wherein utilized spline fitted portion that outer shaft 17 and interior axle 18 can freely be transmitted rotating force and can be combined with displacement with respect to axial direction.In addition, under the situation of present embodiment, with the rearward end spline fitted of the front end of above-mentioned outer shaft 17 and interior axle 18, simultaneously, via synthetic resin with they combinations.Thereby above-mentioned outer shaft 17 and interior axle 18 make this synthetic resin fracture when collision, can shorten whole length.
In addition, above-mentioned steering shaft 2 is inserted the steering column 15 of the tubular that connects, column jacket 19 and inner prop 20 are combined into the specular formation of looking in the distance, form so-called under the situation of the impact that applies axial direction, one side absorbs the telescopic structure that is simultaneously shortened its whole length by the energy of this impacts generation.And, with the front end of above-mentioned inner prop 20, in conjunction with being fixed on main part 135 that constitutes gear-box 22a and the ear end face that covers the main part 135 in 136.This gear-box 22a utilizes not shown bolt etc. above-mentioned cover 136 to be attached on the front end of this main part 135 and constitutes.In addition, axle in above-mentioned 18 is inserted the inboard that connects said gear case 22a, make the front end of axle 18 in this outstanding from the front-end face of above-mentioned cover 136.
In addition, above-mentioned steering column 15 utilizes on the following part that waits vehicle body 26 that supporting bracket 24 is bearing in vibration damper with the intermediate portion.In addition, between this supporting bracket 24 and vehicle body 26, not shown fixing part is set, under the impact of directed forward was applied to situation on this supporting bracket 24, this supporting bracket 24 broke away from from said fixing portion.In addition, the upper end portion of said gear case 22a also is bearing on the part of above-mentioned vehicle body 26.And then, by leaning device being set and the mirror mechanism of looking in the distance, can freely regulate the front and back position and the height and position of aforementioned steering wheel 1.Because this leaning device and the mirror mechanism of looking in the distance are in the past known, are not the characteristics of present embodiment, so, its detailed description omitted.
In addition, axle 139 in the first interior axle 138 and second is linked, constitute above-mentioned interior axle 18 by utilizing torsion bar 140 (Figure 19,20).This torsion bar 140 inserts the inboard that connects this second interior axle 139, the rearward end (right part of Figure 20) of this torsion bar 140 is attached on the front end (left part of Figure 20) of axle 138 in above-mentioned first, the front end (left part of Figure 20) of this torsion bar 140 is attached on the front end (left part of Figure 20) of axle 139 in above-mentioned second.Aforementioned torque sensor 3, relative sense of rotation and relative rotating amount according to axle 138,139 in above-mentioned first, second two that cause because of reversing of above-mentioned torsion bar 140, detect the direction and the size that are applied to the torque on the steering shaft 2 from steering wheel 1, the signal (testing signal) of representing checkout value is sent to aforementioned controller 6.And this controller 6 is sent to aforementioned electric motivation 31 according to this testing signal with the signal that drives usefulness, along the size generation assist torque of direction to stipulate of regulation.
In addition, axle 139 front end in above-mentioned second, the outstanding part of front-end face from the cover 136 that constitutes said gear case 22a via universal joint 7, is attached on the rearward end of jack shaft 8 (Figure 18).In addition, the input shaft 10 (Figure 18) with steering gear mechanism 9 is attached on the front end of this jack shaft 8 via other universal joint 7.Aforementioned small gear 11 is attached on this input shaft 10.In addition, aforementioned tooth bar 12 is engaged on this small gear 11.In addition, in order to prevent from ground to be applied to vibration transfer on the jack shaft 8 to above-mentioned steering wheel 1, also can on above-mentioned each universal joint 7, shock arrester (-tor) be set via wheel.
In addition, aforementioned worm speed reducer 16a comprises: free outer embedding is fixed in above-mentioned second the worm gear 28 on spools 39 the part, worm shaft 29, elastic force imparting mechanism 137.In addition, this elastic force imparting mechanism 137 comprises and is turned round helical spring 141, preload pad 142.
And then above-mentioned worm gear 28 and worm shaft 29 are arranged on the inboard of said gear case 22a, make worm screw 27 engagements of this worm gear 28 and the intermediate portion that is arranged on this worm shaft 29.In addition, above-mentioned motor 31 comprises: in conjunction with the shell 23 that is fixed on the said gear case 22a, be arranged on the permanent magnetism stator 39 made of iron (Figure 21) on the inner peripheral surface of this shell 23, be arranged on the running shaft 32 of the inboard of this shell 23, be arranged on the rotor 38 (Figure 21) of the intermediate portion of this running shaft 32 with state with said stator 39 subtends.
In addition, be located at constitute above-mentioned shell 23 the central part of base plate 40 on the inner peripheral surface of shrinkage pool 41 and the base end part outer circumferential face of above-mentioned running shaft 32 between, first ball bearing 34 is set, with the base end part of this running shaft 32 (Figure 19,21 left part) but with respect to above-mentioned shell 23 free rotary ground supportings.In addition, between the intermediate portion outer circumferential face of the inner circumference edge of being located at the partition wall portion 42 on the intermediate portion inner circumference edge of above-mentioned shell 23 and above-mentioned running shaft 32, second ball bearing 35 is set, but with the intermediate portion of this running shaft 32 with respect to these partition wall portion 42 free rotary ground supportings.
And then, utilize spline fitted portion 33 that the end of above-mentioned two axles 29,32 is connected to each other, wherein, described spline fitted portion 33 constitutes by positive spline part 51 spline fitted on the front end of the cloudy spline part 50 on the inner peripheral surface that makes the base end part of being located at aforementioned worm shaft 29 (Figure 19,22 left part) and the running shaft 32 that is arranged on aforementioned electric motivation 31.According to this structure, above-mentioned worm shaft 29 is with above-mentioned running shaft 32 rotations.
In addition, bearing cage 149 is set, simultaneously, above-mentioned worm shaft 19 can be rotated freely the ground bearing on this bearing cage 149 in the inboard of aforesaid gears case 22a.This bearing cage 149 utilizes annulus portion 152 that major diameter tube portion 150 and minor diameter tube portion 151 are linked.
And, will constitute the outer shroud 57 embedded inboards that are fixed to this major diameter tube portion 150 of the 3rd ball bearing 36.In addition, make the end face (Figure 19,22 right side) of the axial direction of this outer shroud 57 run into a face of above-mentioned annulus portion 152 (Figure 19,22 left surface), simultaneously, utilize retaining ring 154 on the inner peripheral surface be fixed to above-mentioned major diameter tube portion 150 to push down another end face of the axial direction of this outer shroud 57 (Fig. 2,5 left side).In addition, will constitute the interior ring 52 of above-mentioned the 3rd ball bearing 36, on the outer circumferential face near the cardinal extremity part of above-mentioned worm shaft 29, outer embedding is fixed to respect on the consistent part of axial direction and above-mentioned spline fitted portion 33.And then, make above-mentioned in the end face (Figure 19,22 right side) of ring 52 axial direction run into the side that is arranged near the lip part 53 on the outer circumferential face of the cardinal extremity part of above-mentioned worm shaft 29, simultaneously, utilize retaining ring 155 on the base end part inner peripheral surface be fixed to above-mentioned worm shaft 29 push down above-mentioned in another end face (Figure 19,22 left side) of axial direction of ring 52.In addition, as above-mentioned the 3rd ball bearing 36, preferably, use the ball bearing of 4 point-contact types.
And then under the situation of present embodiment, above-mentioned bearing cage 149 can be freely swung is bearing in the inboard of said gear case 22a with displacement.For this reason, on the part of the minor diameter tube portion 151 that constitutes this bearing cage 149, on two positions of the opposition side of the radial direction of aforementioned worm gear 28 sides (Figure 19,22 upside), form a pair of first through hole 158.And, as shown in figure 23, swing axis 159 is avoided the inboard that above-mentioned worm shaft 29 is inserted into above-mentioned bearing cage 149 by described each first through hole 158, simultaneously, by Spielpassung, the part of above-mentioned swing axis 159 near two ends is embedded in described each first through hole 158.And then, two ends at this swing axis 159, from above-mentioned each first through hole 158, will be projected into the part in the outside of above-mentioned bearing cage 149, be embedded in the shrinkage pool 160 and second through hole 161 that is arranged on the main part 135 that constitutes said gear case 22a by Spielpassung respectively.
In addition, make the wall portion 162 of the cover 136 that constitutes said gear case 22a, overlap on the outer circumferential face that in aforementioned body portion 135, is provided with above-mentioned second through hole, 161 parts, from above-mentioned second through hole 161, get loose so that prevent above-mentioned swing axis 159.Utilize this structure, above-mentioned bearing cage 149 is the center with above-mentioned swing axis 159, can freely swing with respect to said gear case 22a and support with displacement.In addition, different with the situation of present embodiment, also can be by stationary fit, will one of be fixed in above-mentioned each first through hole 158 and the above-mentioned shrinkage pool 160 and second through hole 161 near the part at the two ends of above-mentioned swing axis 159 is embedded.
In addition, under the situation of present embodiment, will with by some Q (Figure 19,20) and with the central shaft o of worm gear 28 2The central shaft as above-mentioned swing axis 159 that (Figure 19,22) is parallel, wherein, some Q is positioned at the central shaft o that comprises an x and be parallel to worm-wheel shaft 29 1Straight line L on, some x is positioned at central shaft o from worm shaft 29 1(Figure 19,20,22) to worm gear 28 lateral deviations from the position, be the worm screw 27 of worm shaft 29 and the pitch circle P of worm gear 28 1, P 2Intersection point (Figure 19,20,22).
On the other hand, the front end of above-mentioned worm shaft 29 (Figure 19,22 right part), but utilize the inboard of the 4th ball bearing 37 free rotary ground supportings at said gear case 22a., the outer shroud 60 that constitutes the 4th ball bearing 37 is fixed on second bearing cage 164, this bearing cage 164 is fixed on the inboard of said gear case 22a for this reason.This second bearing cage 164, the cross section is L-shaped, with its whole form circular, with the embedded inboard that is fixed to the tube portion 165 of the side that is arranged on this second bearing cage 164 (Figure 19,22 left side) of above-mentioned outer shroud 60.In addition, on outer circumferential face near the fore-end of above-mentioned worm shaft 29, with the lining 167 roughly cylindraceous of elastic material system, loosely outer being embedded on the large-diameter portion of being located on the part of leaving aforementioned worm screw 27 166.And,, make the front end of above-mentioned worm shaft 29 outstanding from an end face of the axial direction of this lining 167 (Figure 19,22 right side) by the inboard of this lining 167.In addition, the interior ring 65 outer embeddings that constitute above-mentioned the 4th ball bearing 37 are fixed on the intermediate portion of axial direction of this lining 167.In addition, an end face of the axial direction by making in this ring 65 (Figure 19,22 left side), run into the inner side surface of the export-oriented lip part 169 on another end of the axial direction that is arranged on above-mentioned lining 167, carry out above-mentioned in the location of axial direction of ring 65.And,, can make above-mentioned worm shaft 29 within the limits prescribed with respect to this lining 167 tilt (radial direction displacement) by between the outer circumferential face of the inner peripheral surface of above-mentioned lining 167 and above-mentioned large-diameter portion 166, small gap being set.
In addition, at another end face of above-mentioned second bearing cage 164 (Figure 19,22 right side) and be arranged between the bottom surface of the shrinkage pool 72 on the said gear case 22a, the preload pad 142 that constitutes aforementioned elastic force imparting mechanism 137 is set, the minor diameter 171 that is arranged on the front end of above-mentioned worm shaft 29 is not inserted on the part of this preload pad 142 with rocking.This preload pad 142, as the expression at length of Figure 24 institute, the synthetic resin injection molded by will sneaking into solid lubricant etc. are made the shape that a side at two positions of the radial direction opposition side of the outer circumferential face of cylinder is partly removed.In addition, on two positions of the radial direction opposition side of the outer circumferential face of above-mentioned preload pad 142, planar surface portion 172 and arm 173 are separately positioned in half one of worm gear 28 sides (upside of Figure 24) and with the end of these worm gear 28 opposition sides (downside of Figure 24) on.And,, be inserted in the through hole 174 of central part with the state formation of perforation axial direction of above-mentioned preload pad 142 minor diameter 171 of above-mentioned worm shaft 29.The inner peripheral surface of this through hole 171 has the function as the sliding axle of this minor diameter 171 of supporting.In addition, the inner peripheral surface of two ends of this through hole 174 is made the closer to the big more conical surface of opening end diameter.Such preload pad 142 can be bearing in the inboard of being located at the shrinkage pool 72 on the said gear case 22a within the limits prescribed with displacement.
In addition, the aforementioned helical spring 141 of being turned round is set around above-mentioned preload pad 142.And, turned round two ends of helical spring 141 at this, with two locational a pair of fixing parts 175 that are arranged on the radial direction opposition side, on another end face of aforementioned second bearing cage 164, be fixed to a side of a pair of fixed salient 176 of state setting in axial direction outstanding on two positions of radial direction opposition side.In addition, the front end with described each protuberance 176 is embedded in two locational not shown hole portions of the bottom surface that is arranged on above-mentioned shrinkage pool 72.By this structure, limit the position of above-mentioned each fixed salient 176 with respect to aforesaid gears case 22a.And, by in the outer circumferential face that the above-mentioned inner circumference edge of being turned round helical spring 141 flexibly is pressed to above-mentioned preload pad 142, be arranged on the first portion's cylinder face 177 with above-mentioned worm gear 28 opposition sides, give the elastic force of the direction of pointing to aforementioned worm gear 28 to the front end of above-mentioned worm shaft 29 via above-mentioned preload pad 142.
Promptly, under the state before in the front end with above-mentioned worm shaft 29 is inserted into the through hole 174 that is arranged on the above-mentioned preload pad 142, the central shaft of this through hole 174 is with respect to the central shaft of above-mentioned second bearing cage 164 amesiality (Figure 19,20,22,24 upside).Therefore, when the front end with above-mentioned worm shaft 29 is inserted into the through hole 174 that is arranged on the above-mentioned preload pad 142 inboard, first portion's cylinder face 177 by being arranged on this preload pad 142 flexibly enlarges the above-mentioned diameter of being turned round helical spring 141.And, become the tendency that flexibly resets to this (diameter reduction) direction of being turned round the coiling of helical spring 141, turned round helical spring 141 is given elastic force from the direction of pointing to above-mentioned worm gear 28 to the front end of above-mentioned worm shaft 29 from this.According to this structure, outer embedding is fixed with the aforementioned second interior axle 139 of this worm gear 28 and the central shaft distance each other of above-mentioned worm shaft 29 flexibly shortens.Consequently, the worm screw 27 of above-mentioned worm shaft 29 contacts with the state of giving preload each other with the flank of tooth of above-mentioned worm gear 28.
In addition, under the situation of present embodiment, in the outer circumferential face of above-mentioned preload pad 142, make the radius of curvature of the second portion cylinder face 178 that is arranged on above-mentioned worm gear 28 sides littler than the radius of curvature of above-mentioned first portion cylinder face 177.In addition, be provided with around the above-mentioned preload pad 142 under the above-mentioned state of being turned round helical spring 141, on the surface of the wire member that constitutes this each circle of being turned round helical spring 141, and (between line and the line) is provided with the gap of axial direction between the surface of the other wire rod parts adjacent with these each wire rod parts.
On the other hand, for above-mentioned worm shaft 29 and aforementioned the 3rd ball bearing 36 and bearing cage 149 are assembled to the inboard of aforesaid gears case 22a, at first, above-mentioned the 3rd ball bearing 36 and bearing cage 149 are assembled to this worm shaft 29 base end part around.Secondly, these worm shafts 29 and the 3rd ball bearing 36 and bearing cage 149 are configured in the inboard of said gear case 22a.And, each first through hole 158 on will being located at this bearing cage 149 and being provided with is to constitute in the part of main part 135 of this gear-box 22a two locational shrinkage pools 160 of subtend mutually and second through hole 161 states of coupling mutually, aforementioned swing axis 159 is inserted connect and be bearing in these each first, second through holes 158,161 and the shrinkage pool 160.In addition, under the wall portion 162 that makes the cover 136 that constitutes said gear case 22a overlaps state on the part that this second through hole 161 is set in the aforementioned body portion 135, utilize not shown bolt etc., aforementioned body portion 135 and this cover 136 are combined.
As mentioned above, under the situation of the electric type power steering device of the worm speed reducer of present embodiment and this retarder of packing into, utilization is given the elastic force that points to the direction of worm gear 28 front end of worm shaft 29 by turning round helical spring 141 and preload pad 142 constitutes elasticity imparting mechanism 137.Therefore, can utilize cheap structure, the engaging piece of giving described worm gear 28 and the worm screw 27 of worm shaft 29 can be suppressed at the generation of beating dental of this engaging piece with preload.And, under the situation of present embodiment, will become the swing axis 159 of the oscillation center axle of above-mentioned worm shaft 29, with the central shaft o of this worm gear 28 2Be arranged on central shaft o abreast from this worm shaft 29 1On the position of above-mentioned worm gear 28 sides.Therefore, from above-mentioned worm shaft 29 when this worm gear 28 transmits the driving force of motor 31, though apply reaction force to this worm shaft 29 along the axial direction of this worm shaft 29 from this worm gear 28, but the moment on this worm shaft 29 of the generation that the reaction force owing to this axial direction can be caused is dwindled or made it is 0.Thereby, be applied to the reaction force of the radial direction on the above-mentioned worm shaft 29 from above-mentioned worm gear 28, can suppress the change that the influence by above-mentioned moment causes.Thereby, can suppress to return performance difference on two sense of rotation for what make the steering wheel 1 needed power of rotation or this steering wheel 1.
Particularly, under the situation of present embodiment, will with by some Q and with the central shaft o of worm gear 28 2Parallel axle is as the central shaft of above-mentioned swing axis 159, and wherein, some Q is positioned at the central shaft o that comprises an x and be parallel to worm-wheel shaft 29 1Straight line L on, some x is positioned at central shaft o from worm shaft 29 1To worm gear 28 lateral deviations from the position, be the worm screw 27 of worm shaft 29 and the pitch circle P of worm gear 28 1, P 2Intersection point.Therefore, although apply reaction force to above-mentioned worm shaft 29 along the axial direction of this worm shaft 29 from above-mentioned worm gear 28,, can so that can not cause owing to the reaction force of this axial direction moment (this moment is become 0) takes place on this worm shaft 29.Thereby, can eliminate make the above-mentioned steering wheel 1 needed power of rotation and this steering wheel 1 return the difference of performance on two sense of rotation.
In addition, under the situation of present embodiment,, can swing supporting with displacement with respect to gear-box 22a with the bearing cage 149 of supporting the 3rd ball bearing 36.Therefore, as the 3rd ball bearing 36, use the general employed ball bearing of past on the part that swing axis is not fixedly installed on outer shroud, and can suppress the rising of cost with the 3rd ball bearing 36 with respect to said gear case 22a hole swing supporting with displacement.
And then, under the situation of present embodiment, for the axial direction of above-mentioned worm shaft 29, between the engaging piece of the 3rd ball bearing 36 of motor 31 sides in the 3rd, the 4th ball bearing 36,37 at these worm shaft 29 two ends of supporting and the worm screw 27 of above-mentioned worm shaft 29 and worm gear 28, above-mentioned swing axis 159 is set.Therefore, dwindle the swing displacement amount of base end part of motor 31 sides of this worm shaft 29, and can give above-mentioned engaging piece, can more effectively be suppressed at the ear-piercing generation of beating dental of this engaging piece with big preload.In addition, different with the situation of present embodiment, under situation about swing axis being arranged on for above-mentioned engaging piece with the opposition side of motor 31, it is big that the swing displacement of the base end part of above-mentioned worm shaft 29 becomes.
In addition, for above-mentioned engaging piece, aforementioned elastic force imparting mechanism 137 is arranged on opposition side with above-mentioned swing axis 159.Therefore, can increase the elastic deformation amount who is turned round helical spring 141 who constitutes this elastic force imparting mechanism 137, the size that can be easy to regulate the elastic force of giving above-mentioned worm shaft 29.
In addition, under the situation of present embodiment, because above-mentioned preload pad 142 is synthetic resin manufacturings, so, be easy to the front end of above-mentioned worm shaft 29 is inserted into the inboard that is arranged on the through hole 174 on this preload pad 142.In addition, under the surface of the wire rod parts that constitute above-mentioned each circle of being turned round helical spring 141 and situation that the surface of the other wire rod parts of described each wire rod members abut in axial direction contacts, produce friction at this contacting part, become by the above-mentioned helical spring 141 of being turned round and give the reason that inappropriate variation takes place the elastic force of above-mentioned worm shaft 29.Relative therewith, under the situation of present embodiment, because each other on the surface of the other wire rod parts of the surface of wire rod parts of above-mentioned each circle and these each wire rod members abut, the gap of axial direction is set, so, can more stably give the elastic force of above-mentioned worm shaft 29 with regulation.
Embodiment 6
Figure 25～26 expression embodiments of the invention 6.Under the situation of present embodiment, at the outer circumferential face of the close two end portions of the swing axis 159 of block bearing retainer 149 usefulness with displacement that can freely swing with respect to gear-box 22a, and be arranged between the inner peripheral surface of each first through hole 158 on this supporting retainer 149, elastic ring 179 is set respectively.These elastic rings 179 utilize the linking department of making as the rubber of elastic material 182, and the internal side diameter cylindrical part 180 that is respectively the metal manufacturing is linked up mutually with one heart with outside diameter cylindrical part 181.That is, these each linking departments 182 sulfurations are bonded on above-mentioned two cylindrical part 180,181, described two cylindrical part 180,181 are connected to each other.In addition, described each linking department 182 is arranged on the state that is separated from each other on two positions of opposition side of radial direction of the part between described two cylindrical part 180,181.Specifically, on two positions of worm gear 28 sides (with reference to Figure 19,20,22) in the part that above-mentioned each linking department 182,182 is arranged between this and the end of opposition side (two positions at Figure 25,26 above-below direction two end part), will with the part that described each linking department 182 is set mutually phase difference 90 with respect to two ends (two ends of the surface of Figure 19 and back side direction, two ends of the left and right directions of Figure 20) of the axial direction of worm shaft 29 as space portion 183.According to this structure, be different in a circumferential direction with respect to the rigidity of above-mentioned each elastic ring 179 of the radial direction of above-mentioned swing axis 159.In addition, with respect to the rigidity step-down of described each elastic ring 179 of the axial direction of above-mentioned worm shaft 29.
According to the worm speed reducer of this present embodiment, the rotating torques of worm shaft 29 is increased, can be suppressed at the worm screw 27 of this worm shaft 29 and the engaging piece of worm gear 28 dental takes place to beat.That is, under the situation that worm shaft 29 can not be supported with respect to axial direction with displacement with respect to gear-box 22a, under whirling vibration was input to situation on the above-mentioned worm gear 28, above-mentioned worm shaft 29 rotatablely moved easily.In addition, because the running shaft 32 (with reference to Figure 19,21,22) of the motor 31 that moment of inertia is big is attached on this worm shaft 29, so because the whirling vibration of above-mentioned worm gear 28, the power of transmitting each other at the flank of tooth of the worm screw 27 of this worm shaft 29 and above-mentioned worm gear 28 increases.Thereby, applying under the situation of this power, for described two flank of tooth can not separate each other, be necessary to increase the elastic force utilize elastic force imparting mechanism 137 (with reference to Figure 19 etc.) to give above-mentioned worm shaft 29, but, under the excessive situation of this elastic force, the rotating torques of this worm shaft 29 is increased.Relative therewith, under the situation of present embodiment, between bearing cage 149 and swing axis 159, the elastic ring 179 that a part is made for elastic material is set.Therefore, under whirling vibration is input to situation on the above-mentioned worm gear 28, can be easy to make the displacement in axial direction of above-mentioned worm shaft 29, can be difficult to this worm shaft 29 is rotatablely moved.Therefore, can dwindle the power of between above-mentioned each flank of tooth, transmitting.Consequently, the rotating torques of this worm shaft 29 is increased, can prevent that described each flank of tooth is detached from each other, can be suppressed at above-mentioned engaging piece dental takes place to beat.And then, by described two vibrations that flank of tooth collision each other causes, be difficult to be delivered to said gear case 22a, can suppress the generation of the abnormal sound that causes by this vibration.
In addition, under the situation of present embodiment, the rigidity that makes above-mentioned each elastic ring 179 is in the circumferencial direction difference, and simultaneously, reduction is with respect to the rigidity of each spring shackle 179 of the axial direction of worm shaft 29.Therefore, both can guarantee the necessary rigidity of the integral body of described each elastic ring 179, can be easy to again above-mentioned worm shaft 29 along axial direction with respect to gear-box 22a displacement.Thereby, can more effectively suppress the increase of the rotating torques of this worm shaft 29.About other structure and effect, because identical with the described embodiment's 5 in above-mentioned Figure 18～24 situation, so, give identical label for equal part, omit its repeat specification.
Embodiment 7
Figure 27 represents embodiments of the invention 7.Under the situation of present embodiment,, be arranged between two end outer circumferential faces of the inner peripheral surface of the shrinkage pool 160 be located on the gear-box 22a and second through hole 161 and swing axis 159 elastic ring 179 that uses among the embodiment 6 shown in above-mentioned Figure 25～26.About other structure and effect, the same with the foregoing description 6.In addition, in the described embodiment's 6,7 in above-mentioned Figure 25～27 structure, the elastic material as the linking department 182 that constitutes elastic ring 179 also can use the elastomer except that rubber, synthetic resin etc.In addition, also can make whole elastic ring 179 with the synthetic resin elastomeric material.
Embodiment 8
Figure 28～29 expression embodiments of the invention 8.Under the situation of present embodiment, in the described embodiment's 5 in aforementioned Figure 18～24 structure, will be arranged on as the helical spring 186 of elastic force imparting mechanism between the running shaft 32 and worm shaft 29 of motor 31.Promptly, under the situation of present embodiment, recess 184 is provided with on the end face (right side of Figure 28) of this running shaft 32, simultaneously, above-mentioned helical spring 186 is arranged on the bottom surface of this recess 184 and is located between the bottom surface of the splined hole 185 on the base end part (left side of Figure 28) of above-mentioned worm shaft 29.And,, give the elastic force of the direction of above-mentioned worm shaft 29 to leave above-mentioned running shaft 32 by this helical spring 186.In addition, under the situation of present embodiment, also the situation with the foregoing description 5～7 is the same, will become the swing axis 159 of the oscillation center axle of above-mentioned worm shaft 29, is arranged on from the central shaft o1 of this worm shaft 29 on the position of worm gear 28 sides (upside of Figure 28) skew.According to this structure, this worm shaft 29, with above-mentioned swing axis 159 as the center, flexibly to these worm gear 28 side oscillation displacements.
In addition, under the situation of present embodiment, the front end outer circumferential face of above-mentioned worm shaft 29 is made the simple barrel surface of not being with ladder, simultaneously, its front end is configured in the inboard of the shrinkage pool of being located on the gear-box 22a 72.And, between the front end outer circumferential face of the inner peripheral surface of this shrinkage pool 72 and above-mentioned worm shaft 29, the elastic ring 187 and the 4th ball bearing 37 that are equivalent to second elastic ring are set.The 4th ball bearing 37 wherein, by interior ring 65 outer embeddings being fixed to the front end of above-mentioned worm shaft 29, be arranged on this front end around.
In addition, above-mentioned elastic ring 187, as Figure 29 institute represents in detail, the linking department 190 that utilizes the rubber elastomeric material to make, the internal side diameter cylindrical part 188 and the outside diameter cylindrical part 189 that will be respectively the metal manufacturing mutually with one heart link up.In addition, described each linking department 190 is arranged on the state that is separated from each other on two positions of opposition side of radial direction of the part between above-mentioned two cylindrical part 188,189.Specifically, only on two positions of two ends of the different direction (left and right directions of Figure 29) of phase phase difference 90 degree for the swing direction of displacement (above-below direction of Figure 29) of the above-mentioned worm shaft 29 in the part between this, above-mentioned each linking department 190 is set.According to this structure, the rigidity of above-mentioned elastic ring 187 along the swing direction of displacement reduction of above-mentioned worm shaft 29, increases along differing the 90 different directions of spending with this swing direction of displacement.
In addition, under the situation of present embodiment, part between above-mentioned each internal side diameter, outside diameter cylindrical part 188,189, on two positions of two ends of the swing direction of displacement that is positioned at above-mentioned worm shaft 29 inner peripheral surfaces that locate, above-mentioned outside diameter cylindrical part 189, the cross section that is provided with as elastomer elastomeric material manufacturings such as rubber is the retainer 191 of partial arc shape.In addition, between the outer circumferential face of the inner peripheral surface of described each retainer 191 and above-mentioned internal side diameter cylindrical part 188, small gap is set.Described each retainer 191 becomes at above-mentioned worm shaft 29 under the situation of tendency of excessive swing displacement, contacts by the outer circumferential face with above-mentioned internal side diameter cylindrical part 188, prevents the excessive swing displacement of this worm shaft 29.This elastic ring 187, above-mentioned internal side diameter cylindrical part 188 outer embeddings are fixed on the outer shroud 60 that constitutes aforementioned the 4th ball bearing 37, simultaneously, by with above-mentioned outside diameter cylindrical part 189 embedded being fixed in the shrinkage pool of being located on the aforesaid gears case 22a 72, and be arranged between above-mentioned worm shaft 29 and the gear-box 22a.
Under the situation of the present embodiment of above-mentioned formation, owing to helical spring 186 is arranged between the cardinal extremity face of end face of running shaft 32 of motor 31 and worm shaft 29, so, can be via the retaining ring on the base end part that is fixed to this worm shaft 29 155, the preload that will be produced by the elastic force of above-mentioned helical spring 186 is given the 3rd ball bearing 36.Therefore, just can suppress the generation of abnormal sound,, can also use the ball bearing of the bigger shallow/deep groove type in axial direction gap, can reduce cost as above-mentioned the 3rd ball bearing 36.
In addition, under the situation of present embodiment,, can make above-mentioned worm shaft 29 swing displacement with respect to gear-box 22a by between the 4th ball bearing 37 and the gear-box 22a of the front end of the above-mentioned worm shaft 29 of supporting, elastic ring 187 being set.Therefore, the inhibition effect of beating dental takes place in the engaging piece of the worm screw that can not undermine at this worm shaft 29 27 and worm gear 28, can prevent the generation of the abnormal sound that the collision by the front end of this worm shaft 29 and above-mentioned the 4th ball bearing 37 causes.
In addition, under the situation of present embodiment, be arranged on the rigidity of the elastic ring 187 between above-mentioned the 4th ball bearing 37 and the gear-box 22a, in the swing direction of displacement reduction of above-mentioned worm shaft 29, simultaneously, increasing on the direction of this swing displacement with the different direction of 90 phase place.Therefore, promptly can prevent above-mentioned worm shaft 29, can more easily carry out of the swing displacement of this worm shaft 29 again, can more effectively be suppressed at the generation of beating dental of above-mentioned engaging piece to above-mentioned worm gear 28 sides to undesirable direction displacement.
In addition, under the situation of present embodiment, because the retainer 191 that the swing displacement of the above-mentioned worm shaft 29 of restriction is used is set on above-mentioned elastic ring 187, so, can prevent the excessive swing displacement of this worm shaft 29.About other structure and effect, because identical with the situation of the embodiment 5 shown in aforementioned Figure 18～24, so, give same label for equal part, omit its repeat specification.
Embodiment 9
Figure 30 represents embodiments of the invention 9.Under the situation of present embodiment, in the embodiment shown in above-mentioned Figure 28～29 8 structure, will be arranged between bearing cage 149 and the gear-box 22a as the helical spring 186 of elastic force imparting mechanism.That is, under the situation of present embodiment, at the internal surface of this gear-box 22a and be arranged between the bottom of the shrinkage pool 192 on the outer circumferential face of the major diameter tube portion 150 that constitutes above-mentioned bearing cage 149, above-mentioned helical spring 186 is set.And,, give the elastic force of the base end part of this worm shaft 29 with radial direction by this helical spring 186.In addition, this helical spring 186 for the axial direction of this worm shaft 29, is arranged on swing axis 159 from the oscillation center that becomes this worm shaft 29 on the position of the terminal side skew of this worm shaft 29.According to this structure, this worm shaft 29 is the center with above-mentioned swing axis 159, flexibly to above-mentioned worm gear 28 side oscillation displacements.
Under the situation of this present embodiment, needn't strengthen the total length that links above-mentioned worm shaft 29 part of formation with the running shaft 32 of motor 31, can give above-mentioned engaging piece with preload.About other structure and effect, because the same with the situation of the embodiment 8 shown in above-mentioned Figure 28～29, so, give identical label for equal part, omit its repeat specification.
Embodiment 10
Figure 31 represents embodiments of the invention 10.Under the situation of present embodiment, in the structure of aforementioned Figure 28～29, the 3rd, the 4 two ball bearing 36,37 that two ends of supporting worm shaft 29 are used, 149a supports by bearing cage.For this reason, under the situation of present embodiment, strengthen to constitute the total length of the minor diameter tube 151a of portion of above-mentioned bearing cage 149a, simultaneously, the intermediate portion at the axial direction of this minor diameter tube 151a of portion forms through hole 193 on the part of circumferencial direction.And, above-mentioned worm shaft 29 is set in the inboard of above-mentioned bearing cage 149a, simultaneously, at the base end part outer circumferential face of this worm shaft 29 and constitute between the inner peripheral surface of major diameter tube portion 150 of above-mentioned bearing cage 149a, and between the front end inner peripheral surface of the front end outer circumferential face of this worm shaft 29 and the above-mentioned minor diameter tube 151a of portion, the 3rd, the 4th each ball bearing 36,37 is set respectively.In addition, at the front end outer circumferential face of the above-mentioned minor diameter tube 151a of portion and be arranged between the inner peripheral surface of the shrinkage pool 72 on the gear-box 22a, be provided with as the elastic ring 194 (being equivalent to elastic material) of elastomer elastomeric material such as rubber manufacturing.And then, on the part of the worm screw 27 of above-mentioned worm shaft 29, will be exposed to part outside this minor diameter tube 151a of portion from being located at through hole 193 on the above-mentioned minor diameter tube 151a of portion, with worm gear 28 engagements.
Under the situation of such present embodiment, with the same under the situation of the embodiment 8 shown in aforementioned Figure 28～29, do not undermining under the situation of effect that dental takes place to beat the worm screw 27 that is suppressed at above-mentioned worm shaft 29 engaging piece with worm gear 28, can prevent to collide the abnormal sound that causes owing to the front end and the 4th ball bearing 37 of this worm shaft 29, and then, can prevent the excessive swing displacement of this worm shaft 29.About other structure and effect, because the same with the situation of the embodiment 8 shown in aforementioned Figure 28～29, so, give identical label for equal part and omit its repeat specification.
Embodiment 11
Figure 32 represents embodiments of the invention 11.Under the situation of present embodiment, in above-mentioned embodiment's 10 shown in Figure 31 structure, on the part of gear-box 22a, with the part of the front-end face subtend of worm shaft 29 on, form the through hole 195 of inside and outside two faces that connect this gear-box 22a.In addition, will be by the lid that the round-ended cylinder shape is arranged 196 as elastomers such as rubber, the manufacturing of synthetic resin elastomeric material, embedded being fixed in this through hole 195.And, will constitute the front end of the minor diameter tube 151a of portion of bearing cage 149a, on the embedded protuberance 198 that is bearing on the front end inner peripheral surface of being located at the tube portion 197 that constitutes this lid 196.Under the situation of present embodiment, above-mentioned lid 196 is equivalent to elastic material.About other structure and effect, because identical with above-mentioned embodiment's 10 shown in Figure 31 situation, so, its repeat specification omitted.
Embodiment 12
Figure 33～34 expression embodiments of the invention 12.Under the situation of present embodiment, in aforementioned embodiment's 10 shown in Figure 31 structure, the board 199 of the front opening of the minor diameter 151a that stops up bearing cage 149a is set, simultaneously, at the in axial direction outstanding axial region 200 of the front-end face central part setting of this board 199.And, at the outer circumferential face of this axial region 200 and be arranged between the inner peripheral surface of shrinkage pool 72 of gear-box 22a, the spring shackle 201 that is equivalent to second spring shackle is set.This elastic ring 201 as the expression in detail of Figure 34 institute, utilizes as linking department 204 that elastomer elastomeric material such as rubber are made, mutual with one heart will be respectively being linked up by the outside diameter cylindrical part 202 and the internal side diameter cylindrical part 203 of metal manufacturing.In addition, make one and half ones (left side of Figure 33) of the axial direction of this outside diameter cylindrical part 202 outstanding to axial direction, make the total length of the total length of above-mentioned outside diameter cylindrical part 202 greater than this internal side diameter cylindrical part 203 from an end face (left side of Figure 33) of the axial direction of above-mentioned internal side diameter cylindrical part 203.In addition, outer periphery portion at the end face (left side of Figure 33) of the axial direction of above-mentioned linking department 204 is provided with to the outstanding protuberance 205 of axial direction, simultaneously, this protuberance 205 is attached on the inner peripheral surface of axial direction one and half ones of above-mentioned outside diameter cylindrical part 202.
And then, on the part of above-mentioned linking department 204, on two positions of the radial direction opposition side at the place, two ends that is positioned at the swing direction of displacement of worm shaft 29 (Figure 16,17 above-below direction), the through hole 206 that in axial direction connects is set.According to this structure, the rigidity of above-mentioned spring shackle 201 along the swing direction of displacement step-down of above-mentioned worm shaft 29, simultaneously, increases along differing 90 rigidity of spending the direction of phase places with this swing direction of displacement.By with above-mentioned outside diameter cylindrical part 202 embedded be fixed to be located on the said gear case 22a shrinkage pool 72 in, simultaneously, the 203 outer embeddings of above-mentioned inside cylindrical portion are fixed on the axial region 200 on the front-end face of being located at above-mentioned bearing cage 149a, this elastic ring 201 is arranged between said gear case 22a and this axial region 200.In addition, make the front end outer circumferential face of the minor diameter tube 151a of portion that constitutes above-mentioned bearing cage 149a via small gap and the inner peripheral surface subtend that is arranged on the protuberance 205 on the above-mentioned linking department 204.Under the situation of present embodiment, this protuberance 205 is equivalent to limit the retainer that the swing displacement of worm shaft 29 is used.
Under the situation of such present embodiment, make the low part of rigidity of elastic ring 201, and the protuberance 205 of retainer that plays a part to prevent the undue swing displacement of worm shaft 29, stagger along the axial direction of above-mentioned elastic ring 201.About other structure and effect because and aforementioned embodiment's 10 shown in Figure 31 situation same, so, give identical label for equal part, omit its repeat specification.
Embodiment 13
Figure 35 represents embodiments of the invention 13.Under the situation of present embodiment, has the structure that combines with aforementioned embodiment's 9 shown in Figure 30 structure and aforementioned embodiment 10 shown in Figure 31.Promptly, under the situation of present embodiment, in embodiment shown in Figure 31 10 structure, between the inner peripheral surface of the outer circumferential face of major diameter tube portion 150 supporting the 3rd ball bearing 36 and the 4th ball bearing 37 (with reference to Figure 31), formation bearing cage 149a and gear-box 22a, helical spring 186 is set along the radial direction of this bearing cage 149a.About other structure and effect because and aforementioned embodiment 9 shown in Figure 30 and embodiment's 10 shown in Figure 31 structure same, so, give identical label for equal part, omit its repeat specification.
Embodiment 14
Secondly, Figure 34 represents embodiments of the invention 14.Under the situation of present embodiment, in aforementioned embodiment's 10 shown in Figure 31 structure, with the end (right part of Figure 36) of the running shaft 32a of motor 31 and the base end part (left part of Figure 36) of worm shaft 29a, coupling collar 207 via elastic material is made links up to stop its mutual counterrotating state.This coupling collar 207, as the expression in detail of Figure 37 institute, utilize the elastomer elastomeric material as rubber, make cylindric, at equally spaced a plurality of positions of circumferencial direction (under the situation shown in the figure, 8 positions), formation is roughly leg-of-mutton through hole 208 along the cross section that axial direction connects.
In addition, part at the close external diameter of the cardinal extremity face (Figure 36 institute left side) of above-mentioned worm shaft 29a, with near a plurality of positions of the circumferencial direction of the outer radius portion of the end face (right side of Figure 36) of above-mentioned running shaft 32a (under the situation of example shown in the figure, 4 positions), with the through hole 208 that is arranged on the above-mentioned coupling collar 207 on the position of a through-hole alignment, in axial direction outstanding protuberance 209a, 209b are set respectively.These each protuberances 209a, 209b freely are not embedded in each through hole 208 of being located on the above-mentioned coupling collar 207 with rocking respectively.And, by being located at each protuberance 209a on the above-mentioned worm shaft 29a and being located at each protuberance 299b on the above-mentioned running shaft 32a, alternately, be not embedded in above-mentioned each through hole 208 along circumferencial direction from the both sides of the axial direction of above-mentioned coupling collar 207 with rocking, above-mentioned worm shaft 29a and running shaft 49a linked up via above-mentioned coupling collar 207.In addition, under the situation of present embodiment, between the end face central part of the bottom surface of the shrinkage pool 210 of the cardinal extremity face central part of being located at above-mentioned worm shaft 29a and above-mentioned running shaft 32a, helical spring 186 is set, give above-mentioned worm shaft 29a elastic force along the direction of leaving this running shaft 32a.
Under the situation of such present embodiment, above-mentioned worm shaft 29a and running shaft 32a are linked up via shackle 207.Therefore, between these running shafts 32a and worm shaft 29a, be difficult to transmitting vibrations.About other structure and effect because and aforementioned embodiment's 10 shown in Figure 31 situation same, so, give identical label for equal part, omit its repeat specification.
In addition, diagram is omitted, and is different with the situation of present embodiment, on the formation position of being located at each through hole 208 on the above-mentioned coupling collar 207, replaces each through hole 208, and also can alternately be provided with respectively along circumferencial direction respectively is first, second a plurality of recesses.In this case, can be with the bottom of these each first, second recesses, as the opposition side for the axial direction of above-mentioned coupling collar 207.And, by each protuberance 209a on the cardinal extremity face that will be arranged on worm shaft, with each protuberance 209b on the end face that is arranged on above-mentioned running shaft 32a, be embedded into respectively in above-mentioned each first, second recess, above-mentioned worm shaft 29a and running shaft 32a linked up via above-mentioned coupling collar 207.
In addition, in the foregoing description 5～14, but also can be between bearing cage 149,149a and the gear-box 22a of at least one ball bearing 36 in the 3rd, the 4th Ball support 36,37 of the close two end portions of supporting free rotary ground supporting worm shaft 29,29a (perhaps 37), repack with grease.Under the situation that adopts this structure, between above-mentioned worm shaft 29,29a and worm gear 28 during transmission of drive force, because the reaction force that applies to this worm shaft 29,29a from this worm gear 28, this worm shaft 29,29a produce under the situation of the tendency of leaving this worm gear 28, are not easy to make above-mentioned bearing cage 149,149a to swing displacement.And, when above-mentioned driving force increases, when above-mentioned reaction force becomes big, have the speed that above-mentioned worm shaft 29,29a leave above-mentioned worm gear 28 and become big tendency, still, in this case, the viscosity of lubricating grease also increases.Therefore, can suppress the swing displacement of above-mentioned bearing cage 149,149a, can be easy to prevent that the worm screw 20 of above-mentioned worm shaft 29,29a is separated from one another with the flank of tooth of worm gear 28.
In addition, in the foregoing description 5～14, can utilize the magnesium alloy manufacturing to be used for supporting to rotate freely supporting near one of them ball bearing 36 at least of the 3rd, the 4th Ball support 36,37 of the part at the two ends of worm shaft 29,29a (perhaps 37) bearing cage 149,149a.Under the situation that adopts this structure, owing to can utilize above-mentioned bearing cage 149,149a to absorb at an easy rate because the worm screw 20 of above-mentioned worm shaft 29,29a and the flank of tooth of worm gear 28 collide the vibration that occurs on worm shaft 29, the 29a each other, so this vibration is difficult to be delivered on the gear-box 22a.
In addition, in these cases, make small gear 11 and directly engagement of tooth bar 19 (with reference to Figure 46) on the end that is fixed to pinion shaft 10 (with reference to Fig. 5,46), but the present invention is not limited to this structure.For example, also can will the structure of so-called speed of a motor vehicle servo-actuated optional gear ratio mechanism (VGS) and the textural association of the foregoing description 5～14 be housed, wherein said speed of a motor vehicle servo-actuated optional gear ratio mechanism (VGS), with the pin that is arranged on the underpart of pinion shaft, in the slotted hole of the small gear that is arranged with this pinion shaft branch, can cooperate with displacement along the length direction freedom of this slotted hole, simultaneously, make the engagement of this small gear and tooth bar, the displacement amount that makes tooth bar according to the speed of a motor vehicle changes with respect to the ratio of the angle of swing of steering shaft.
In addition, the present invention is not limited to motor 31 is arranged on the structure on every side of steering shaft 2.For example, as shown in figure 38, also motor 31 can be arranged on the periphery of the small gear 11 (with reference to Fig. 5,46) that meshes with tooth bar 12.And, under the situation of this structure shown in Figure 38, the worm gear that constitutes worm speed reducer 16a be fixed to above-mentioned small gear or be bearing on the part of the member on this small gear.Under the situation of this structure shown in Figure 38, also can torque sensor 3 (with reference to Figure 46) be arranged on steering shaft 2 around, and be arranged on the periphery of above-mentioned small gear 11.Utilize this structure shown in Figure 38, also can implement the present invention.
And then, as shown in figure 39, also can be on the part of tooth bar 12, being engaged to the periphery that leaves with the locational secondary small gear 211 of the auxiliary section of small gear 11, motor 31 is set.Under the situation of this structure shown in Figure 39, make the worm gear and worm shaft 29 (29a) engagement that are fixed on this pair small gear 211.Under the situation of this structure shown in Figure 39, also torque sensor 3 (with reference to Figure 46) can be arranged on the periphery of above-mentioned small gear 11.
In addition, under the situation of structure shown in Figure 39,, damping device 212 is set, is used to prevent from ground to be delivered to vibration on the above-mentioned small gear 11, on direction of transfer dish 1 via wheel at the intermediate portion of jack shaft 8.For example, this damping device 212 is looked in the distance specularly by interior axle and outer shaft are combined into, and simultaneously, elastic material is attached between the end side face of these two axles and constitutes.Utilize this structure shown in Figure 39, also can implement the present invention.
Embodiment 15
Secondly, Figure 40～45 expression embodiments of the invention 15.The electric type power steering device of present embodiment, comprise: as steering wheel 1 is fixed to rearward end (with reference to Fig. 1, the steering shaft 2 of auxiliary axis 46 etc.) is (with reference to Fig. 1,46 etc.), the axial columns 15 that this steering shaft 2 freely can be inserted perforation is (with reference to Fig. 1,46 etc.), give the worm speed reducer 16b that this steering shaft 2 is used with assist torque, be arranged on the small gear 11 (with reference to 46) of the forward end of this steering shaft 2, with this small gear 11 or be bearing in the tooth bar (with reference to 46) of the member engagement on this small gear 11, torque sensor 3 (with reference to 46), motor 31, controller 6 (with reference to 46).
Above-mentioned worm speed reducer 16b comprises; Can free outer embedding be fixed to the worm gear 28 on interior 18 of constituting above-mentioned steering shaft 2 (with reference to Fig. 1 etc.) the part, worm shaft 29 is turned round helical spring 30a, preload pad 213a.
In addition, above-mentioned torque sensor 3, be arranged on above-mentioned steering shaft 2 intermediate portion around, detect the direction and the size that are applied to the torque on this steering shaft 2 from above-mentioned steering wheel 1, with the expression checkout value signal (testing signal) be sent to controller 6.And this controller 6 is according to this testing signal, sends the signal that drives above-mentioned motor 31 usefulness, makes it to take place along the assist torque of the size of the regulation of the direction of regulation.
In addition, above-mentioned worm gear 28 and worm shaft 29 are arranged on the inboard of gear-box 22, and this worm gear 28 and the worm screw 27 of the intermediate portion that is arranged on this worm shaft 29 are meshed.In addition, the spline fitted portion 33 that utilization constitutes positive spline part 51 spline fitted of cloudy spline part 50 and the front end that is arranged on the running shaft 32 that constitutes above-mentioned motor 31 on the inner peripheral surface of the base end part (left part of Figure 40) that is arranged on this worm shaft 29, the end of above-mentioned two axles 29,32 is connected to each other.According to this structure, above-mentioned worm shaft 29 and above-mentioned running shaft 32 rotate together.
In addition, utilize the 3rd ball bearing 36 as clutch shaft bearing, but with the base end part free rotary ground supporting of above-mentioned worm shaft 29 inboard at said gear case 22.In addition, will constitute the interior ring 52 of the 3rd ball bearing 36, on outer circumferential face, be embedded into outward with respect on the consistent part of axial direction and above-mentioned spline fitted portion 33 near the cardinal extremity part of above-mentioned worm shaft 29.And, make the axial direction middle position of this spline fitted portion 33 consistent basically with the axial direction middle position of above-mentioned the 3rd ball bearing 36.In addition, between the outer circumferential face by ring 52 inner peripheral surface in above-mentioned and above-mentioned worm shaft 29, small gap is set, above-mentioned worm shaft 29 can be within the limits prescribed with respect to 36 inclinations of above-mentioned the 3rd ball bearing.In addition, two end faces of the axial direction of ring 52 in above-mentioned, and between the side of the side of lip part 53 and lip part 214, elastic ring 215 is set respectively, wherein, the base end part that described lip part 53 is arranged near above-mentioned worm shaft 29 divides on the outer circumferential face, and described lip part 214 is arranged on the outer circumferential face that screw-thread fit is fixed to the nut 55 on the outer screw section 54 on the base end part of being located at this worm shaft 29.And, in the side of above-mentioned each lip part 53,214 each other, flexibly clamping above-mentioned in ring 52.According to this structure, can be in the scope of in axial direction regulation elastic displacement ground with respect to the above-mentioned worm shaft 29 of above-mentioned the 3rd ball bearing 36 supportings.In addition, preferably,, use the ball bearing of 4 point-contact types as above-mentioned the 3rd ball bearing 36.
On the other hand, utilize the 4th ball bearing 37 as second bearing, with the front end of above-mentioned worm shaft 29 (Figure 40,41 right part), but free rotary ground supporting is in the inboard of said gear case 22.For this reason, under the situation of present embodiment, will be as bearing cage 216 embedded being fixed in the shrinkage pool of being located on the said gear case 22 72 of buffer component.This bearing cage 216 is at length represented as Figure 41～45, is respectively that pair of bearings retainer element 217 with the synthetic resin manufacturing is combined into an integral body and constitutes, and large diameter cylinder portion 218 and small diameter cylinder portion 219 is linked mutually with one heart constitute.On two positions of the diametric(al) opposition side of the inner peripheral surface of large diameter cylinder portion 218 therein, the pair of planar portion 234 (Figure 43) that is parallel to each other is set.In addition, this large diameter cylinder portion 218, with the end of above-mentioned small diameter cylinder portion 219 opposition sides (Figure 40,41 left part, the end of the depths of Figure 44) on the inner peripheral surface, differing on 90 the bit position mutually, with above-mentioned each planar surface portion 234,234 respectively to form a pair of inward flange 220a of portion, 220b to the side-prominent state of internal diameter.And, make the interval between the inner side surface of the 220a of these inward flange portions, 220b and the inner side surface of above-mentioned small diameter cylinder portion 219 (Figure 40,41 left surface), substantially the same with the size of the axial direction of the outer shroud 60 that constitutes above-mentioned the 4th ball bearing 37.In addition, the internal diameter of the part of each planar surface portion 234 is left in order on the inner peripheral surface of above-mentioned large diameter cylinder portion 218, is a bit larger tham the external diameter of this outer shroud 60.On the other hand, make above-mentioned each planar surface portion 234 interval d each other 234, roughly the same with the external diameter of this outer shroud 60.According to this structure, under the embedded state that is bearing in the above-mentioned large diameter cylinder portion 218 with this outer shroud 60, stop of the displacement of this outer shroud 60 to axial direction, on the other hand, at this outer shroud 60 in the radial direction, only, can carry out displacement in the scope of (running into the inner peripheral surface of large diameter cylinder portion 218) regulation of the direction of above-mentioned each planar surface portion 234 up to the outer circumferential face of outer shroud 60.That is, above-mentioned outer shroud 60 is prevented from along the displacement of Figure 43,44 left and right directions, and then the axial direction intermediate portion at the outer circumferential face of above-mentioned large diameter cylinder portion 218 spreads all over whole circumference, forms fixed groove 221.This bearing cage 216, two end faces of the circumferencial direction by making above-mentioned pair of bearings retainer element 217 dock formation each other, wherein, described bearing cage element 217 has and comprises central shaft by utilization and at interior imaginary plane this bearing cage 216 is divided into two shapes that obtain.
And then, at the central part of the circumferencial direction that is arranged on the semicircular cylinder portion 223 on above-mentioned each bearing cage element 217 that constitutes above-mentioned small diameter cylinder portion 219 usefulness, the plat part 233 parallel with above-mentioned each planar surface portion 234 is set respectively.And, on the intermediate portion of these plat parts 233, form notch 222a, the 222b (Figure 42,44,45) that connects radial direction with the one end at the state of the end face upper shed of above-mentioned each plat part portion 233 respectively.Above-mentioned each notch 222a, 222b are used for fixing two ends being turned round helical spring 30a of describing later, as (b) institute's expression in detail of Figure 45 (a), have different shape mutually.That is, these each otch 222a, 222b are from the length of front-end face till the end of deep of above-mentioned each plat part 233, different mutually.In addition, at the deep end of above-mentioned each otch 222a, 222b, described each otch 222a, 222b are set each other along the curved part 235 of equidirectional bending.Make above-mentioned each bearing cage element 217 combinations, constituting under the state of above-mentioned bearing cage 216, above-mentioned each otch 222a, 222b are present on two positions of the opposition side of radial direction basically of this bearing cage 216.
And, as shown in figure 43, under the state that above-mentioned the 4th ball bearing 37 is assembled, mode in order to the entire portion of two sides of the axial direction that covers the outer shroud 60 that constitutes the 4th ball bearing 37 with the large diameter cylinder portion 218 of above-mentioned bearing cage 216 and the 220a of inward flange portion, 220b and small diameter cylinder portion 219 (Figure 41) and outer circumferential face, two end faces of the circumferencial direction of above-mentioned pair of bearings retainer element 217 are docked each other, form above-mentioned bearing cage 216.And, in this state, will be fixed on the said fixing groove 221 by the elastic ring 224 that elastomer as rubber etc. constitutes.In addition, at the internal side diameter of the interior ring 65 that constitutes above-mentioned the 4th ball bearing 37, in axial direction the slide lining 225 of usefulness of embedded permission worm shaft 29.
In addition, the inboard in the small diameter cylinder portion 219 that constitutes above-mentioned bearing cage 216, configuration preload pad 213a.This preload pad 213a, at length represent as Figure 43, synthetic resin injection molded by will sneaking into solid lubricant etc., make roughly cylindric, on the outer circumferential face of two ends of this preload pad 213a, form fixed salient 230 to spread all over whole circumference to the side-prominent state of external diameter respectively.In addition,, will be located at, freely do not insert the inboard of the through hole 231 that is provided with the state that connects axial direction with rocking near the minor diameter 68 on the front end of worm shaft 29 at the central part of this preload pad 213a.The inner peripheral surface of this through hole 231 has the function as the sliding bearing of this minor diameter 68 of supporting.In addition, in this through hole 231, on the inner peripheral surface of the terminal side end of above-mentioned worm shaft 29, be provided with the closer to the big more conical surface 232 of beginning diameter.
And, to be embedded in outward under the state on every side of above-mentioned preload pad 231a as the elastomeric above-mentioned main body (spiral part) of being turned round helical spring 30a, this preload pad 213a will be configured in the inboard of the small diameter cylinder portion 219 that constitutes above-mentioned bearing cage 216.In addition, order is on the inner peripheral surface of this small diameter cylinder portion 219, with the part interval d each other of each plat part 233 subtends 233, bigger slightly than the external diameter that is arranged on each fixed salient 230 on the above-mentioned preload pad 213a.In this state, this preload pad 213a, the inboard in this small diameter cylinder portion 219, the outer periphery of above-mentioned each fixed salient 230 can be met the displacement of the inner peripheral surface of this small diameter cylinder portion 219 always.And then, will above-mentionedly turned round on two ends of helical spring 30a, two positions at the radial direction opposition side, with a pair of fixing part 73a that the state to external diameter lateral bending song is provided with, be fixed on pair of notches 222a, the 222b that is formed on the plat part 233 that constitutes above-mentioned small diameter cylinder portion 219.In addition, the above-mentioned helical spring 30a that turned round is being fixed under the state on described each otch 222a, the 222b, make this central position of being turned round the main body of helical spring 30a, be partial to one distolateral (upper end side of Figure 40～44) of the circumferencial direction of above-mentioned each bearing cage element 217.In addition, be arranged on the curved part 235 on above-mentioned each otch 222a, 222b, have the function that prevents that above-mentioned each fixing part 73a, 73b from coming off from above-mentioned each notch 222a, 222b.
And, like this, with above-mentioned bearing cage 216 and aforementioned the 4th ball bearing 37 and above-mentioned preload pad 213a with turned round under the state that helical spring 30a combines, with these bearing cage 216 embedded being fixed in the shrinkage pool of being located on the aforesaid gears case 22 72 (Figure 40,41).Promptly, in the embedded large diameter cylinder portion 226 that is fixed to the open end side that constitutes this through hole 72 of the large diameter cylinder portion 218 of above-mentioned bearing cage 216, simultaneously, with above-mentioned elastic ring 224, flexibly be compressed between the bottom surface of the inner peripheral surface of large diameter cylinder portion 226 of this shrinkage pool 72 and said fixing groove 221.In addition, between the outer circumferential face of the small diameter cylinder portion 219 of the inner peripheral surface of the small diameter cylinder portion 227 of the underside side that constitutes above-mentioned shrinkage pool 72 and above-mentioned bearing cage 216, form roughly circular gap 228.In this state, the part of two sides of the outer circumferential face of above-mentioned the 4th ball bearing 37 and axial direction, covered by above-mentioned bearing cage 216, stop above-mentioned the 4th ball bearing 37 with respect to this bearing cage 216 displacement in axial direction, simultaneously, allow the 4th ball bearing 37 in radial direction with respect to this bearing cage 216 along each planar surface portion 234 displacement within the limits prescribed.
In addition, like this, will be located near the large-diameter portion 63 of the fore-end of above-mentioned worm shaft 29, loosely insert the inboard that connects lining 225, wherein, described lining 225 is embedded into via bearing cage 216 and is bearing on the 4th ball bearing 37 in the gear-box 22.And large-diameter portion 63 can be with respect to this lining 225 displacement in axial direction.Meanwhile, the minor diameter 68 with being arranged on the front end of above-mentioned worm shaft 29 is not inserted in the through hole of being located on the above-mentioned preload pad 213a 231 with rocking.According to this structure, via this preload pad 213a, on the front end of this worm shaft 29, give the elastic force of the direction of pointing to worm gear 28 from the above-mentioned helical spring 30a that turned round.Promptly, under the state before in the front end with above-mentioned worm shaft 29 is inserted into the through hole of being located on this preload pad 231a 231, the central shaft of this through hole 231, with respect to the central shaft of above-mentioned bearing cage 216 and shrinkage pool 72, amesiality (upsides of Figure 40～42).And, being accompanied by the inboard that the front end of above-mentioned worm shaft 29 is inserted into this through hole 231, the above-mentioned diameter of being turned round helical spring 30a is flexibly expanded by the outer circumferential face of above-mentioned preload pad 213a.And, turned round helical spring 30a by this and become tendency to the direction elastic reset of (diameter reduction) of reeling, turned round helical spring 30a gives above-mentioned worm shaft 29 via above-mentioned preload pad 213a front end elastic force from this with the direction of pointing to worm gear 28.According to this structure, the aforementioned interior axle 18 that these worm shaft 28 outer build-ins are fixed flexibly shrinks with the central shaft distance to each other of above-mentioned worm shaft 29.Consequently, the worm screw 27 of above-mentioned worm shaft 29 contacts with the state of giving preload each other with the flank of tooth of above-mentioned worm gear 28.
In addition, under the situation of present embodiment, make the in-plane (Figure 40,41 with the direction parallel face of paper) of two ends interface of the circumferencial direction of above-mentioned each bearing cage element 217 that constitutes above-mentioned bearing cage 216 be turned round helical spring 30a to give above-mentioned worm shaft 29 consistent with the direction of elastic force with utilizing.In addition, different with the situation of present embodiment, two end faces of the circumferencial direction of above-mentioned each bearing cage element 217 are run into, form the gap each other at described two end faces.In addition, under situation about constituting like this, preferably, make by the imaginary plane of this gap portion consistent with the direction of giving above-mentioned elastic force.
As mentioned above, at the worm speed reducer of present embodiment and be equipped with under the situation of electric type power steering device of this retarder, utilize and turned round helical spring 30a, the front end of giving worm shaft 29 via preload pad 213a is with the elastic force of the direction of pointing to worm gear 28.Therefore, utilize cheap structure, the engaging piece that can give described worm gear 28 and the worm screw 27 of worm shaft 29 can be suppressed at the dental of beating of this engaging piece with preload.And, under the situation of present embodiment,, but still can at an easy rate the preload of giving above-mentioned engaging piece stably be maintained in the limited narrow scope although apply the power of axial direction to worm shaft 29 from worm gear 28.Therefore, can be suppressed at the generation that this engaging piece is beaten dental effectively.
That is, under the situation of present embodiment, allow worm shaft 29 in axial direction with respect to give above-mentioned worm shaft 29 with elastic force with preload pad 213a and support the 4th ball bearing 37 that the front end of this worm shaft 29 uses and carry out displacement.Therefore, when motor 31 drives, even applying spooling under the situation of the reaction force of direction to this worm shaft 29 from worm gear 28, above-mentioned preload pad 213a and the 4th ball bearing 37 can be owing to the axial direction of this reaction force along this worm shaft 29 is urged on other the member at full tilt yet.Thereby, to be turned round helical spring 30a by utilization and given this worm shaft 29 with elastic force via above-mentioned preload pad 213a, the preload that can prevent to give above-mentioned worm gear 28 and the engaging piece of the worm screw 27 of worm shaft 29 produces big change because of the influence of above-mentioned reaction force.Consequently, can be easy to this preload is maintained in the limited narrow scope long-term and stably, can be suppressed at the generation of beating dental of above-mentioned engaging piece effectively.
In addition, make the bearing cage 216 of the displacement of above-mentioned the 4th ball bearing 37 of restriction owing to utilize synthetic resin, so, can dwindle the frictional force that acts between described the 4th ball bearing 37 and the bearing cage 216, can be easy to make the 4th ball bearing 37 displacement radially.Therefore, can more effectively be suppressed at the generation of beating dental of above-mentioned engaging piece.In addition, utilize above-mentioned bearing cage 216 that the part of two sides of the outer circumferential face of the 4th ball bearing 37 and axial direction is covered, limit above-mentioned the 4th ball bearing 37 with respect to this bearing cage 216 displacement in axial direction.Therefore, above-mentioned worm shaft 29 in axial direction can be pressed on the 4th ball bearing 37, can be easy to suppress this rocking of bearing 37 of playing ball.
In addition, under the situation of present embodiment, stop the 4th ball bearing 37, simultaneously, allow the 4th ball bearing 37 with respect to the prescribed direction displacement radially of this bearing cage 216 with respect to the displacement in axial direction of above-mentioned bearing cage 216.Therefore, in above-mentioned worm shaft 29 and the 37 one side relative displacements in axial direction of the 4th ball bearing, these worm shaft 29 one sides are swung under the situation of displacement, the sliding friction between the inner peripheral surface of interior ring 65 of the outer circumferential face of this worm shaft 29 and above-mentioned the 4th ball bearing 37 can be easy to dwindle, this swing displacement can be easy to carry out smoothly.Consequently, dwindle whole frictional loss, can give the preload of above-mentioned engaging piece at an easy rate with the best.
And then, under the situation of present embodiment, owing between above-mentioned bearing cage 216 and gear-box 22, elastic ring 224 is set, so, can be easy to suppress this bearing cage 216 rocking with respect to this gear-box 22.Therefore, can be easy to carry out the size Control of each several part, simultaneously, can be easy to the engagement of above-mentioned engaging piece is remained on best state.And then, when being assembled to above-mentioned bearing cage 216 in the said gear case 22, can between the bottom surface of the fixed groove 221 of the inner peripheral surface of the shrinkage pool 72 of this gear-box 22 and this bearing cage 216, flexibly compress above-mentioned elastic ring 224.Therefore, can prevent simultaneously that this bearing cage 216 one side that comes off in the above-mentioned shrinkage pool 72 from carrying out the assembling work of above-mentioned bearing cage 216, can carry out the assembling work of this bearing cage 216 at an easy rate.
In addition, under the situation of present embodiment, constitute above-mentioned bearing cage 216 by pair of bearings retainer element 217, wherein, described bearing cage element 217 has the imaginary plane that utilizes the central shaft that comprises this bearing cage 216 above-mentioned bearing cage is divided into two shapes that obtain.Therefore, the forming operation in order to obtain each bearing cage element 217 that this bearing cage 216 carried out is more prone to, simultaneously, the easier operation of carrying out the 4th ball bearing 37 is assembled into the inboard of this bearing cage 216.And then, make the in-plane of interface at the circumferencial direction two ends of above-mentioned each bearing cage element 217 be turned round helical spring 30a to give the direction of elastic force of worm shaft 29 consistent with utilizing.Therefore, under the situation of these worm shaft 29 swing displacements, the displacement of the radial direction of the 4th ball bearing 37 is not easy to be subjected to the obstruction of above-mentioned bearing cage 216, can carry out the swing displacement of this worm shaft 29 easilier.
And then, under the situation of present embodiment, on the outer circumferential face of two ends of the axial direction of above-mentioned preload pad 213a, outstanding laterally fixed salient 230 is set.Therefore, can prevent to be turned round helical spring 30a and come off, simultaneously, can limit this and be turned round the displacement of helical spring 30a with respect to these preload pad 213 axial directions from the outer circumferential face of this preload pad 213.About other structure and effect, because same with the situation of the embodiment shown in the earlier figures 1～9, so, give identical label for equal part, omit its explanation and diagram.
In addition, different with the situation of present embodiment, also can be by constituting above-mentioned bearing cage 216 as bearing cage element 217 butt joints of independent member, but utilize single member to constitute this bearing cage, simultaneously, on the part of the circumferencial direction of this solid memder, the otch of the whole length that spreads all over axial direction is set.Under situation about constituting like this, the diameter of above-mentioned bearing cage 216 can be flexibly enlarged, the operation of the inboard of this bearing cage 216 can be easy to carry out the 4th ball bearing 37 is assembled in the mode that limits the 4th ball bearing 37 displacement in axial direction.In addition, utilize above-mentioned bearing cage 216, be easy to absorb the size error and the assembly error of the parts on every side that are arranged on this bearing cage 216.In addition, under the situation of temperature variation, also can absorb the dimensional changes that is arranged on the notch portion on this bearing cage 216 around, can suppress the otch dimensional changes in addition of this bearing cage 216.
In addition, can between above-mentioned bearing cage 216 and the 4th ball bearing 37, resilient member be set.Under the situation of this structure, can be easy to suppress above-mentioned the 4th ball bearing 37 rocking with respect to this bearing cage 216.Therefore, can be easy to carry out the size Control of each several part, simultaneously, can be easy to the engagement at above-mentioned engaging piece is maintained best state.And then one side is compressed to above-mentioned resilient member between this bearing cage 216 and the 4th ball bearing 37, simultaneously carries out above-mentioned the 4th ball bearing 37 is assembled into operation on the above-mentioned bearing cage 216.Therefore, when carrying out above-mentioned operation, can prevent that the 4th ball bearing 37 from coming off, and is easy to carry out the assembling operation of the 4th ball bearing 37 in this bearing cage 216.
In addition, under the situation of the foregoing description 15, for small gear 11 and the direct situation about meshing of tooth bar 12 (with reference to Figure 44) on the end that is fixed to pinion shaft 10 (with reference to Fig. 1,44) are illustrated.But the present invention is not limited to this structure.For example, also can will the structure of so-called speed of a motor vehicle servo-actuated optional gear ratio mechanism (VGS) and the textural association of present embodiment be housed, wherein said speed of a motor vehicle servo-actuated optional gear ratio mechanism (VGS), with the pin that is arranged on the underpart of pinion shaft, in the slotted hole of the small gear that is arranged with this pinion shaft branch, can cooperate with displacement along the length direction freedom of this slotted hole, simultaneously, make the engagement of this small gear and tooth bar, the displacement amount that makes tooth bar according to the speed of a motor vehicle changes with respect to the ratio of the angle of swing of steering shaft.
In addition, the present invention is not limited to motor is arranged on the structure on every side of steering shaft 2.For example, shown in Figure 15 as described above, utilize the structure that motor 31 is arranged on the periphery of the small gear 11 (with reference to Figure 44) that meshes with tooth bar 12, also can implement the present invention.Under the situation of this structure as shown in figure 15, the worm gear that constitutes worm speed reducer 16 is fixed to above-mentioned small gear 11 or is bearing on the part of the member on this small gear 11.Under the situation of this structure shown in Figure 15, also can torque sensor 3 (with reference to Figure 44) be arranged on steering shaft 2 around, and be arranged on the periphery of small gear 11.
In addition, shown in Figure 16 as described above, utilize on the part of tooth bar 12, at the periphery of the locational secondary small gear 75 that is engaged to the auxiliary section of leaving small gear 11 structure of motor 31 is set, also can implement the present invention.Under the situation of this structure shown in Figure 16, make the worm gear and worm shaft 29 engagements that are fixed on this pair small gear 75.Under the situation of this structure shown in Figure 16, also torque sensor 3 (with reference to Figure 44) can be arranged on the periphery of above-mentioned small gear 11.In addition, under the situation of structure shown in Figure 44, on the intermediate portion of jack shaft 8, damping device 76 is set, is used to prevent that the vibration transfer that is delivered on the above-mentioned small gear 11 via wheel from ground from giving steering wheel 1.For example, this damping device 76 is looked in the distance specularly by interior axle and outer shaft are combined into, and simultaneously, elastic material is attached between the end side face of described two axles and constitutes.
Like this, auxiliary axis of the present invention can be steering shaft, small gear, be engaged to any one member in the secondary small gear on the tooth bar etc. in the position of leaving this small gear.
In addition, the situation of the rotor phase detector used of the present invention's direction of being not limited to utilize brush 48 and transducer 46 (with reference to Fig. 2,3) to constitute to switch the field current that is sent to the coil 45 that forms motor 31.For example, also can utilize the permanent magnetism encoder 78 made of iron and the Hall integrated circuit 77 that are fixed on the running shaft 32 to constitute the rotor phase detector as shown in figure 17, motor 31 is made so-called brushless structure.In addition, under the situation of aforementioned structure shown in Figure 17, the coil 83 that utilization is fixed to the iron core 82 of the lamination steel plate system on the inner peripheral surface of shell 23 and is wound up into a plurality of positions of this iron core 82 constitutes stator 39a, simultaneously, utilize the permanent magnet 84 on the intermediate portion outer circumferential face that is fixed on above-mentioned running shaft 32 to constitute rotor 38a.In addition, adopting under the situation of this structure, also can be sent to the vector control apparatus of increase and decrease of size of the electric current of said stator 39a, switching the magnetic force of this stator 39a by control is set.
And then, under the situation of the foregoing description 15, be illustrated for the situation that worm speed reducer is encased in the electric type power steering device.But worm speed reducer of the present invention is not limited to be used for this purposes, also can be encased in the linear actuator in the various mechanical devices such as being installed in beddo, electronic desk, electronic chair, lift to use.For example, under the situation in worm speed reducer being encased in this electric linear actuator, after with of the rotational delay of this worm speed reducer with motor, extract on the running shaft, via ball screw etc. make be arranged on this running shaft around output shaft flexible.The present invention also goes for this worm speed reducer that is encased in the electric linear actuator.

Claims (28)

1. a worm speed reducer comprises worm gear, and worm shaft, elastomer, this elastomer are given worm shaft to point to the elastic force of worm gear direction.
2. worm speed reducer as claimed in claim 1, it is characterized in that, elastomer is given worm shaft to point to the elastic force of worm gear direction via the preload pad, this worm gear can freely be fixed on the auxiliary axis, above-mentioned worm shaft, to be bearing in the inboard of gear-box near the part at its two ends by pair of bearings, simultaneously, be arranged on the worm screw and the engagement of above-mentioned worm gear of this worm shaft intermediate portion, above-mentioned preload pad, utilization is arranged on the said gear case or is fixed on the guide surface of the member on this gear-box, limit its displacement with respect to prescribed direction, and,, eliminate or dwindle the gap of itself and above-mentioned guide surface by the resiliently deformable of the preload advance capital for body that causes by elastomeric elastic force.
3. worm speed reducer as claimed in claim 1, it is characterized in that, elastomer is given worm shaft to point to the elastic force of worm gear direction via the preload pad, this worm gear can freely be fixed on the auxiliary axis, above-mentioned worm shaft, to be bearing in the inboard of gear-box near the part at its two ends by pair of bearings, simultaneously, be arranged on the worm screw and the engagement of above-mentioned worm gear of this worm shaft intermediate portion, above-mentioned preload pad is made of a pair of element, utilization is arranged on the said gear case or is fixed on the guide surface of the member on this gear-box, limit its displacement with respect to the direction of regulation, and, by make by elastomeric elastic force above-mentioned a pair of element to mutually away from the direction displacement, eliminate or dwindle gap between itself and the above-mentioned guide surface.
4. as claim 2 or 3 described worm speed reducers, it is characterized in that the preload pad can be along the direction of guide surface displacement, tilt at interior imaginary plane with respect to the central shaft that comprises worm shaft, the engaging piece that is arranged on the worm and wheel on this worm shaft.
5. electric type power steering device, comprise: the steering shaft that steering wheel is set in rearward end, be arranged on the small gear of the forward end of this steering shaft, with this small gear or be bearing in the tooth bar of the member engagement on this small gear, any one described worm speed reducer in the claim 2～4, rotation drives the motor that worm shaft is used, detection is applied to the torque sensor of the direction and the big or small usefulness of the torque on above-mentioned steering shaft or the small gear, according to the controller that the drive condition of the above-mentioned motor of importing from this torque sensor of SC sigmal control is used, auxiliary axis is above-mentioned steering shaft, above-mentioned small gear, be engaged to any one member in the secondary small gear on the above-mentioned tooth bar in position away from this small gear.
6. worm speed reducer as claimed in claim 1, it is characterized in that, elastomer is the elastic force imparting mechanism, worm shaft, by rotatable and swing supporting with displacement, simultaneously, be arranged on the worm and wheel engagement of intermediate portion with respect to gear-box, from the central shaft of this worm shaft to the position that above-mentioned worm gear lateral deviation is moved, with the central axes of this worm gear the oscillation center axle of above-mentioned worm shaft is set.
7. worm speed reducer as claimed in claim 6, it is characterized in that, will by with the straight line of the central axes of worm shaft on 1 point and with the axle of the central axes of this worm gear, oscillation center axle as above-mentioned worm shaft, wherein, described straight line comprises the intersection point of the pitch circle of the worm screw of above-mentioned worm shaft and above-mentioned worm gear.
8. as claim 6 or 7 described worm speed reducers, it is characterized in that, can swing block bearing retainer with displacement with respect to gear-box, but described bearing cage is used for supporting at least one bearing of pair of bearings of part at the close two ends of free rotary ground supporting worm shaft.
9. as any one described worm speed reducer in the claim 6～8, it is characterized in that, axial direction with respect to worm shaft, but between the engaging piece of the bearing of the motor side in the pair of bearings of the close two end portions of this worm shaft of free rotary ground supporting and the worm screw of this worm shaft and worm gear, the oscillation center axle of worm shaft is set.
10. as any one described worm speed reducer in the claim 6～9, it is characterized in that, with respect to the worm screw of worm shaft and the engaging piece of worm gear,, be provided for giving the elastic force imparting mechanism of the elastic force of this worm shaft to point to the worm gear direction at the opposition side of the oscillation center axle of this worm shaft.
11. as any one described worm speed reducer in the claim 6～10, it is characterized in that, but will be used to support the bearing cage near the part of an end of the above-mentioned worm shaft of free rotary ground supporting, can be bearing in displacement in the said gear case by the swing axis swing, between described gear-box and the swing axis or between described bearing cage and swing axis, elastic material is set.
12. as any one described worm speed reducer in the claim 6～10, it is characterized in that, but will be used to support the bearing cage near the bearing of the part of an end of the above-mentioned worm shaft of free rotary ground supporting, can swing by swing axis and be bearing in displacement in the said gear case, between described gear-box and swing axis, perhaps between described bearing cage and swing axis, it is the elastic ring of elastic material that at least a portion is set, simultaneously, make that the rigidity of the above-mentioned elastic ring of being correlated with the radial direction of the oscillation center axle of above-mentioned worm shaft is different in a circumferential direction.
13. as any one described worm speed reducer in the claim 6～9, it is characterized in that, between the running shaft of worm shaft and motor, be provided for giving the elastic force imparting mechanism of the elastic force of this worm shaft to point to the worm gear direction.
14. as any one described worm speed reducer in the claim 6～9, it is characterized in that, between bearing cage and said gear case, the elastic force imparting mechanism that this worm shaft is used with the elastic force that points to above-mentioned worm gear direction is given in setting, wherein, described bearing cage, but be used for supporting at least one bearing of pair of bearings of part at the close two ends of the above-mentioned worm shaft of free rotary ground supporting.
15. as any one described worm speed reducer in the claim 6～14, it is characterized in that, by supporting near in the pair of bearings of the part at above-mentioned worm shaft two ends away from bearing of the oscillation center axle of above-mentioned worm shaft and gear-box between elastic material is set, can make above-mentioned worm shaft with respect to this gear-box swing displacement.
16. as any one described worm speed reducer in the claim 6～14, it is characterized in that, by between away from bearing of the oscillation center axle of this worm shaft in the pair of bearings of part at close the two ends of the above-mentioned worm shaft of supporting and gear-box, second elastic ring that at least a portion is the elastic material manufacturing being set, can make above-mentioned worm shaft with respect to this gear-box swing displacement, simultaneously, make in the rigidity of this second elastic ring different with respect to the rigidity of the swing direction of displacement of this worm shaft with rigidity with respect to other direction.
17. as claim 15 or the described worm speed reducer of claim 16, it is characterized in that, on the elastic material or second elastic ring be located between a bearing and the gear-box, the retainer used of swing displacement of restriction worm shaft be set.
18. as any one described worm speed reducer in the claim 6～17, it is characterized in that, link the running shaft and the worm shaft of motor via elastic material.
19. as any one described worm speed reducer in the claim 6～18, it is characterized in that, repack with grease between bearing cage and said gear case, wherein, but described bearing cage is used for supporting at least one bearing of pair of bearings of part at the close two ends of the above-mentioned worm shaft of free rotary ground supporting.
20. as any one described worm speed reducer in the claim 6～19, it is characterized in that, but the bearing cage that at least one bearing in the pair of bearings of the part at the close two ends of the above-mentioned worm shaft of supporting free rotary ground supporting is used is made with magnesium alloy.
21. electric type power steering device, comprise: the steering shaft that steering wheel is set in rearward end, be arranged on the small gear of the forward end of this steering shaft, with this small gear or be bearing in the tooth bar of the member engagement on this small gear, according to any one described worm speed reducer in the claim 6～20, rotation drives the motor that worm shaft is used, detection is applied to the torque sensor of the direction and the big or small usefulness of the torque on above-mentioned steering shaft or the small gear, controller according to the drive condition of the above-mentioned motor of importing from this torque sensor of SC sigmal control is used is fixed to above-mentioned steering shaft with above-mentioned worm gear, above-mentioned small gear, perhaps be engaged in the secondary small gear on the above-mentioned tooth bar on any one member in the position of leaving this small gear.
22. worm speed reducer as claimed in claim 1, it is characterized in that, elastomer is given the elastic force of the direction of worm shaft to point to worm gear via the preload pad, this worm gear freely is fixed on the auxiliary axis, above-mentioned worm shaft, utilize clutch shaft bearing its part near an end to be bearing in the inboard of gear-box, utilize second bearing its part near the other end to be bearing in the inboard of gear-box, simultaneously, be arranged on the worm screw and the engagement of above-mentioned worm gear of intermediate portion, and, can be that swing at the center with above-mentioned clutch shaft bearing, above-mentioned second bearing, cover at least a portion of two sides of its outer circumferential face and axial direction by being fixed to plastic buffer component on the said gear case, limit second bearing with respect to the displacement in axial direction of this buffer component, allow of the displacement of above-mentioned worm shaft with respect to the axial direction of the above-mentioned preload pad and second bearing.
23. worm speed reducer as claimed in claim 22 is characterized in that, buffer component is provided with otch along the whole length that the part of circumferencial direction spreads all over axial direction.
24. as claim 22 or the described worm speed reducer of claim 23, it is characterized in that, second bearing is prevented from respect to the displacement of buffer component at the axial direction of this second bearing, simultaneously, allows this second bearing with respect to the radial direction displacement of this buffer component along this second bearing.
25. as any one described worm speed reducer in the claim 22～24, it is characterized in that, between buffer component and gear-box, perhaps between the buffer component and second bearing, resilient member be set.
26. as any one described worm speed reducer in the claim 22～25, it is characterized in that buffer component is made of a pair of element, described a pair of element has the shape that the imaginary plane by the central shaft that comprises this buffer component is divided into two and obtains.
27. worm speed reducer as claimed in claim 26 is characterized in that, order makes the in-plane of the face that a pair of element docks each other consistent with the direction of the elastic force of being given worm shaft by elastomer.
28. electric type power steering device, comprise: the steering shaft that steering wheel is set in rearward end, be arranged on the small gear of the forward end of this steering shaft, with this small gear or be bearing in the tooth bar of the member engagement on this small gear, according to any one described worm speed reducer in the claim 22～27, rotation drives the motor that worm shaft is used, detection is applied to the torque sensor of the direction and the big or small usefulness of the torque on above-mentioned steering shaft or the small gear, according to the controller that the drive condition of the above-mentioned motor of importing from this torque sensor of SC sigmal control is used, auxiliary axis is above-mentioned steering shaft, above-mentioned small gear, be engaged to any one member in the secondary small gear on the above-mentioned tooth bar in position away from this small gear.
CNB2004800022698A 2003-06-25 2004-06-24 Worm speed reducer and electric power steering device Expired - Fee Related CN100476241C (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP180959/2003 2003-06-25
JP2003180959 2003-06-25
JP271418/2003 2003-07-07
JP181600/2004 2004-06-18

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CN101476615B (en) * 2009-01-21 2011-04-13 安徽省绩溪县今都齿轮有限责任公司 Improved hard tooth surface worm-gear speed reducer
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