CN102893057A

CN102893057A - Worm gear mechanism and electric power steering device using same

Info

Publication number: CN102893057A
Application number: CN2011800240902A
Authority: CN
Inventors: 青木高大; 清水康夫; 白石岳人
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2010-08-23
Filing date: 2011-08-03
Publication date: 2013-01-23
Also published as: WO2012026296A1; JP2013249846A

Abstract

The present invention is a worm gear mechanism (44) that comprises a worm (80), a torque transmission worm wheel (90), and an auxiliary worm wheel (100). The auxiliary worm wheel is positioned at the center line (CL) of rotation of the torque transmission worm wheel, is caused to overlap the torque transmission worm wheel, and is positioned by a positioning section (110). The positioning section comprises a positioning receiving section (111) and a positioning convex section (112) that that can fit into the positioning receiving section. The positioning receiving section is formed on one of either the auxiliary worm wheel or the torque transmission worm wheel, and the positioning convex section is formed on the other of the two.

Description

Worm and gear vice mechanism and use its driven steering device

Technical field

The present invention relates to a kind of worm and gear vice mechanism and use its driven steering device.

Background technique

The worm and gear vice mechanism that is equipped on driven steering device consists of by the worm screw that links with electric motor and with worm gear that the transmission of torque that load links is used.The assist torque that electric motor produces from worm screw through worm gear to load transfer.In recent years, for the technology of the backlash (gap) between the tooth that improves the steering sensation (steering feeling) of driven steering device, develop the tooth that reduces worm screw and worm gear.The technology that reduces this backlash is known at patent documentation 1.

Patent documentation 1 known worm and gear vice mechanism by worm screw, with the transmission of torque of this worm meshing with worm gear, be arranged at this transmission of torque and consist of with the auxiliary worm wheel of worm gear.This auxiliary worm wheel is positioned at one heart with respect to the rotation centerline of transmission of torque with worm gear, and overlaps with worm gear with this transmission of torque.Auxiliary worm wheel is restricted with respect to the relative rotation displacement of transmission of torque with worm gear.

Reduce the tooth of worm screw and the backlash between the transmission of torque usefulness tooth of worm gear by auxiliary worm wheel.In order to reduce this backlash, require suitably design with respect to the relative position relationship of transmission of torque tooth for the tooth of worm gear, auxiliary worm wheel.

Technical paper formerly

Patent documentation

Patent documentation 1: TOHKEMY 2005-337489 communique

Summary of the invention

The problem to be solved in the present invention is that a kind of technology for suitably setting with the relative position of tooth tooth, auxiliary worm wheel of worm gear with respect to transmission of torque is provided.

In the invention of technological scheme 1, a kind of worm and gear vice mechanism is provided, it comprises worm screw, with the transmission of torque usefulness worm gear of this worm meshing and the auxiliary worm wheel that arranges with worm gear in this transmission of torque, by this auxiliary worm wheel the tooth of described worm screw and described transmission of torque are reduced with the backlash between a plurality of teeth of worm gear, wherein, described auxiliary worm wheel is positioned at the position concentric with the rotation centerline of described transmission of torque usefulness worm gear, and coincided with described transmission of torque worm gear, and can be installed by the location, positioning part, this positioning part comprises: the location receiving portion that forms with the either party of worm gear in described auxiliary worm wheel and described transmission of torque, and be formed at described auxiliary worm wheel and described transmission of torque with the opposing party that appoints of worm gear, can embed the positioning convex portion of described location receiving portion.

In the invention of technological scheme 2, described location receiving portion is formed at the fitting surface of described auxiliary worm wheel and the either party that described transmission of torque is used the fitting surface of worm gear, and described positioning convex portion is formed at the opposing party of described fitting surface and the described fitting surface that described transmission of torque is used worm gear of described auxiliary worm wheel.

In the invention of technological scheme 3, among described location receiving portion and described positioning convex portion, be formed at described transmission of torque and become one with a side of worm gear and this transmission of torque a plurality of profiles of tooth with worm gear.

In the invention of technological scheme 4, one side's at receiving portion place, described location described fitting surface also has the circular-arc elongated slot take described rotation centerline as benchmark, described location receiving portion is made of the recess of a part that is positioned at described elongated slot, and described positioning convex portion can be by embedding described elongated slot be guided by this elongated slot and is indexed to described location receiving portion.

In the invention of technological scheme 5, described transmission of torque has the claw section along described rotation centerline extension towards the opposing party with the either party of worm gear and described auxiliary worm wheel, and described the opposing party has the hooking part that can lock described claw section, be limited to described hooking part by described claw section and limit to the displacement along the direction of described rotation centerline, described auxiliary worm wheel is installed in described transmission of torque worm gear thus.

In the invention of technological scheme 6, described claw section comprises: the arm that extends along the described auxiliary worm wheel of described rotating center alignment with the described fitting surface of worm gear from described transmission of torque; And the outstanding claw of described fitting surface of using worm gear from the front end of this arm along described transmission of torque, described hooking part comprises: connect described auxiliary worm wheel along described rotation centerline, and form the circular-arc through hole take described rotation centerline as benchmark; And along the circular-arc edge that forms this through hole, being formed at the plane of inclination of the non-fitting surface of described auxiliary worm wheel, described through hole comprises: can insert simultaneously the 1st logical through hole for described arm and described claw; And the 2nd through hole that links to each other and only can supply described arm to connect with the 1st through hole, described plane of inclination is at the depth location of the described non-fitting surface of the described auxiliary worm wheel of distance, and the border of described the 1st through hole and described the 2nd through hole has the inclination initial point, and tilt to extend to described non-fitting surface from this inclination initial point along described the 2nd through hole, with the beveled end of this extension as the inclination terminal point, described claw insert with described arm lead in described the 1st through hole after, by with respect to described auxiliary worm wheel take described rotation centerline as benchmark relatively rotates described claw, when described claw is positioned at described non-fitting surface being guided by described plane of inclination, can has and flexibly be limited to this non-fitting surface.

In the invention of technological scheme 7, described location receiving portion is when described claw is limited to the described non-fitting surface of described auxiliary worm wheel, and being positioned at can be on the chimeric position of described positioning convex portion.

In the invention of technological scheme 8, described transmission of torque is the integral piece that mutually is shaped and is integrated by resin material with worm gear, described positioning convex portion, described arm and described claw, and described claw is outstanding towards described rotation centerline from described arm.

In the invention of technological scheme 9, form the claw section along described rotation centerline extension towards the opposing party by the either party who uses worm gear and described auxiliary worm wheel in described transmission of torque, form the hooking part that can embed and can lock described claw section described the opposing party, described positioning convex portion is made of described claw section thus, and described location receiving portion is made of described hooking part, embed and be limited to described hooking part by described claw section, restriction is towards the displacement along the direction of described rotation centerline, and described auxiliary worm wheel is positioned and is installed on described transmission of torque worm gear thus.

In the invention of technological scheme 10, described auxiliary worm wheel has a plurality of teeth that mesh for the described tooth with described worm screw, these a plurality of teeth are by constituting the bending deflection that can have to the sense of rotation of described auxiliary worm wheel spring performance, under the state of the sense of rotation bending of described auxiliary worm wheel, joining with described worm screw, can make thus described worm screw and described transmission of torque with at least one party's rotation of worm gear.

In the invention of technological scheme 11, when described transmission of torque was not all joined with respect to the described tooth of described worm screw with described a plurality of teeth of worm gear, at least one of described a plurality of teeth of described auxiliary worm wheel joined with the described tooth of described worm screw under the state of the sense of rotation bending of described auxiliary worm wheel.

In the invention of technological scheme 12, at least one of described a plurality of teeth of described auxiliary worm wheel joined with the described tooth of described worm screw under the state of the sense of rotation bending of described auxiliary worm wheel all the time.

In the invention of technological scheme 13, when the sense of rotation of described worm screw is switched to reverse direction from positive veer, among described transmission of torque is used a plurality of described tooth of worm gear, before being about to switch to described reverse direction from from the 1st tooth of the described tooth engagement of described worm screw to be engaged in 2nd tooth different with the 1st tooth during, at least one of described a plurality of teeth of described auxiliary worm wheel joined with the described tooth of described worm screw under the state of the sense of rotation bending of described auxiliary worm wheel.

In the invention of technological scheme 14, described auxiliary worm wheel is the formed article that comprises that described a plurality of tooth integral body is integrated by ester moulding.

In the invention of technological scheme 15, a kind of driven steering device that uses the worm and gear vice mechanism is provided, it possesses: described worm and gear vice mechanism; Steering system from the steering wheel of vehicle to the steering wheel; And produce torque and this torque is passed to the electric motor of described steering system through described worm and gear vice mechanism.

The invention effect

In the invention of technological scheme 1, by overlapping auxiliary worm wheel in transmission of torque with worm gear, receiving portion embeds positioning convex portion in the location, thereby auxiliary worm wheel can be positioned at reliably on the phase place of transmission of torque predefined the best for worm gear.Therefore, the tooth of auxiliary worm wheel suitably and easily can be set on the best position with respect to the relative position of transmission of torque with the tooth of worm gear.And, the formation of location so long as the so simple formation of integrated positioning receiving portion and positioning convex portion get final product.

In the invention of technological scheme 2, therefore location receiving portion and positioning convex portion easily embed positioning convex portion in the location receiving portion owing to being positioned at each fitting surface.

In the invention of technological scheme 3, the either party of location receiving portion and positioning convex portion forms as one with the tooth of transmission of torque with worm gear.Therefore, the either party of location receiving portion and positioning convex portion with compared by the situation that other parts consist of with the tooth of worm gear with respect to transmission of torque, but precision is set the position with respect to this tooth well.Therefore, can be reliably and precision set well the tooth of auxiliary worm wheel with respect to the relative position of this tooth.

In the invention of technological scheme 4, location indentations is positioned at the part take the rotation centerline of auxiliary worm wheel as the circular-arc elongated slot of benchmark.Therefore, after circular-arc elongated slot embeds positioning convex portion, by the either party of transmission of torque with worm gear and auxiliary worm wheel rotated take rotation centerline as benchmark, thereby in the chimeric positioning convex portion of the location indentations that is positioned at elongated slot.The worker need not be visual just can be reliably and easily the tooth of auxiliary worm wheel is set on the best position with respect to the relative position of transmission of torque with the tooth of worm gear.Therefore, can reduce assembling number in man-hour.

In the invention of technological scheme 5, by overlapping auxiliary worm wheel in transmission of torque with worm gear, thereby lock claw section at hooking part.Consequently, can be reliably and easily auxiliary worm wheel is assembled in the transmission of torque worm gear.Auxiliary worm wheel after the assembling with not in the axial direction displacement of worm gear, is kept stable assembled state with respect to transmission of torque.

In the invention of technological scheme 6, after arm and claw are inserted through the 1st through hole, relatively rotate take rotation centerline as benchmark with respect to auxiliary worm wheel, thus, while being tilted face, claw guides the non-fitting surface that is positioned at auxiliary worm wheel.Consequently, claw has and flexibly is limited to non-fitting surface.So, overlap and relatively rotate such operation by making auxiliary worm wheel with worm gear with respect to transmission of torque, just can auxiliary worm wheel be installed integratedly on worm gear in transmission of torque, so assembling performance is good.

In the invention of technological scheme 7, when claw was limited to non-fitting surface, positioning convex portion was embedded in location indentations.By making auxiliary worm wheel overlap and relatively rotate such operation with respect to transmission of torque with worm gear, just can with worm gear auxiliary worm wheel be installed in transmission of torque, and reliably and easily the tooth of auxiliary worm wheel be set in best position with respect to transmission of torque with the relative position of the tooth of worm gear.Therefore, assembling performance is good.

In the invention of technological scheme 8, transmission of torque is become one by resin-shaped with worm gear, arm and claw.Because claw is outstanding towards rotation centerline from arm, so can make 2 cut piece along rotation centerline with the molding die of worm gear with being used for the shaping transmission of torque.Therefore, can improve the productivity that transmission of torque is used worm gear.

In the invention of technological scheme 9, claw section has both the function of positioning convex portion, and hooking part has both the function of locating receiving portion.Therefore, can make the auxiliary worm wheel location and be installed on transmission of torque and simplify with the formation of worm gear.

In the invention of technological scheme 10, a plurality of teeth of auxiliary worm wheel constitute the bending deflection that can have " spring performance " to the sense of rotation (positive veer and this two side of reverse direction) of auxiliary worm wheel.The spring performance of so-called tooth refers to: the amount of bow that reaches the tooth that is produced by this loading in the loading that puts on tooth has predefined certain characteristic (that is, tooth self has " function of spring ").Have spring performance and can diastrophic a plurality of teeth by under the state of described sense of rotation bending, joining with worm screw, can make thus worm screw and transmission of torque with at least one party's rotation of worm gear.Consequently, rotate with worm gear or auxiliary worm wheel by making transmission of torque, thereby worm screw is contacted with worm gear with transmission of torque, can reduce the tooth of worm screw and the backlash between the transmission of torque usefulness tooth of worm gear.So, a plurality of teeth self of auxiliary worm wheel can bending deflection owing to having spring performance, does not therefore need be used to the other member that reduces backlash.Therefore, the formation of the worm and gear vice mechanism that reduce backlash is simplified, can be reduced number of spare parts, and can reduce assembling number in man-hour.

In the invention of technological scheme 11, at least before transmission of torque is joined with the tooth of the tooth of worm gear and worm screw, at least one of a plurality of teeth of auxiliary worm wheel joined with the tooth of worm screw under the state of the sense of rotation bending of auxiliary worm wheel.That is, at least one of a plurality of teeth to described sense of rotation to worm screw and the transmission of torque at least one party's application of force with worm gear.Consequently, can reduce reliably the tooth of worm screw and the impact that transmission of torque is used the backlash between the tooth of worm gear.

In the invention of technological scheme 12, at least one of a plurality of teeth of auxiliary worm wheel joined with the tooth of worm screw under the state of the sense of rotation bending of auxiliary worm wheel all the time.Therefore, use between the worm gear worm screw and transmission of torque, when not having the transmission of torque, at least one of a plurality of teeth used at least one party's application of force of worm gear to worm screw and transmission of torque to described sense of rotation.

For example, not from worm screw to transmission of torque during with the worm gear transmitting torque, exist transmission of torque to reverse under external force with worm gear and touch the situation of worm screw.But a plurality of teeth of auxiliary worm wheel are joining with the tooth of worm screw under the state of the sense of rotation bending of auxiliary worm wheel.Therefore, the transmission of torque of reverse with the tooth of worm gear can with the tooth collision of worm screw, but touch lentamente and mesh.The generation of the sound of cramping that can prevent tooth from touching each other and produce.And then, when not using the worm gear transmitting torque from worm screw to transmission of torque, continue to suppress transmission of torque by the tooth with spring performance and reverse under external force with worm gear.Therefore, can reduce reliably the tooth of worm screw and the impact that transmission of torque is used the backlash between the tooth of worm gear.

And then even if because of the long-term worm and gear vice mechanism of using, the tooth of worm screw or transmission of torque be with the odontotripsis of worm gear, and in the situation that backlash will increase, a plurality of teeth of auxiliary worm wheel are also joining with the tooth of worm screw under the state of the sense of rotation bending of auxiliary worm wheel.Therefore, do not need the adjustment operation of backlash.

In the invention of technological scheme 13, when the sense of rotation of worm screw was switched to reverse direction from positive veer, the tooth of the worm screw of reverse was contacted with the tooth that transmission of torque is used worm gear lentamente.The generation of the sound of cramping that can suppress tooth to be touched each other and produce.

In the invention of technological scheme 14, auxiliary worm wheel comprises that a plurality of tooth integral body are become one by resin-shaped.Therefore, can improve the productivity of auxiliary worm wheel.

In the invention of technological scheme 15, in driven steering device, the power transmission mechanism as the torque that electric motor is produced is transmitted to steering system adopts the worm and gear vice mechanism of removing backlash.Therefore, can further improve the durability of power transmission mechanism.And then by removing the backlash of worm and gear vice mechanism, the generation of the tooth sound of cramping each other in the time of can further suppressing the steering wheel steering consequently, can further reduce the indoor noise of car.For example, when the craspedodrome of vehicle is travelled, do not use the worm gear transmitting torque from worm screw to transmission of torque.Under this travelling state, can suppress to be subject to as far as possible vehicle the vibration of travelling impact and tooth is touched each other and produce the sound of cramping.

And then in the invention of technological scheme 15, by removing the backlash of worm and gear vice mechanism, can keep transmission of torque and use worm gear with respect to the good engagement of worm screw.Therefore, when steering wheel being returned the wheel operation, can suppress to transmit from the worm and gear vice mechanism to steering system the generation of the time lag of assist torque.And then, owing to having removed backlash, so when transmission of torque was rotated with worm gear, tooth can not collide each other, but touch lentamente and mesh, therefore can make steering wheel to return the wheel action good.Therefore, can further improve the steering sensation (steering feeling) of driven steering device.

Description of drawings

Fig. 1 is the ideograph of the driven steering device of embodiments of the invention 1.

Fig. 2 is the whole pie graph of driven steering device shown in Figure 1.

Fig. 3 is the sectional drawing along the 3-3 line of Fig. 2.

Fig. 4 is the sectional drawing along the 4-4 line of Fig. 2.

Fig. 5 is the figure that worm and gear vice mechanism shown in Figure 3 is amplified.

Fig. 6 is the sectional drawing that transmission of torque shown in Figure 5 is decomposed with worm gear and auxiliary worm wheel.

Fig. 7 is the stereogram that transmission of torque shown in Figure 6 is used worm gear and auxiliary worm wheel.

Fig. 8 observes the figure that combination transmission of torque shown in Figure 5 is used the structure of worm gear and auxiliary worm wheel from the non-fitting surface side of auxiliary worm wheel.

Fig. 9 is the figure that observes auxiliary worm wheel shown in Figure 8 from non-fitting surface side.

Figure 10 is the figure that observes auxiliary worm wheel shown in Figure 9 from the fitting surface side.

Figure 11 is the explanatory drawing of the relation of explanation positioning part shown in Figure 8, claw section, hooking part.

Figure 12 is the explanatory drawing of the assembling sequence of explanation positioning part shown in Figure 11, claw section, hooking part.

Figure 13 is the explanatory drawing of the assembling finishing stage of explanation positioning part shown in Figure 12, claw section, hooking part.

Figure 14 is the explanatory drawing that explanation transmission of torque shown in Figure 6 is used the shaping order of worm gear.

Figure 15 is the explanatory drawing of meshing engagement structure of each tooth of explanation worm and gear vice mechanism shown in Figure 4.

The explanatory drawing of the meshing engagement structure of each tooth of the worm and gear vice mechanism of Figure 16 when to be explanation transmission of torque shown in Figure 15 with the tooth of worm gear do not contact with worm screw.

The explanatory drawing of the meshing engagement structure of each tooth of the worm and gear vice mechanism of Figure 17 when to be that explanation is shown in Figure 15 reverse worm screw.

Figure 18 is the figure that the worm and gear vice mechanism of embodiments of the invention 2 is amplified.

Figure 19 is the sectional drawing that transmission of torque shown in Figure 180 is decomposed with worm gear and auxiliary worm wheel.

Figure 20 is the stereogram that transmission of torque shown in Figure 19 is used worm gear and auxiliary worm wheel.

Figure 21 observes the figure that combination transmission of torque shown in Figure 180 is used the formation of worm gear and auxiliary worm wheel from transmission of torque with the non-fitting surface side of worm gear.

Figure 22 is the figure that the worm and gear vice mechanism of embodiments of the invention 3 is amplified.

Figure 23 is the sectional drawing that transmission of torque shown in Figure 22 is decomposed with worm gear and auxiliary worm wheel.

Figure 24 is the stereogram that transmission of torque shown in Figure 23 is used worm gear and auxiliary worm wheel.

Figure 25 is the explanatory drawing of the relation of explanation claw section shown in Figure 24 and hooking part.

Figure 26 is the explanatory drawing of the assembling finishing stage of explanation claw section shown in Figure 25 and hooking part.

Figure 27 is the figure that the worm and gear vice mechanism of embodiments of the invention 4 is amplified.

Figure 28 is the sectional drawing that transmission of torque shown in Figure 27 is decomposed with worm gear and auxiliary worm wheel.

Figure 29 is the stereogram that transmission of torque shown in Figure 28 is used worm gear and auxiliary worm wheel.

Figure 30 is the figure that observes auxiliary worm wheel shown in Figure 29 from non-fitting surface side.

Figure 31 is the figure that observes auxiliary worm wheel shown in Figure 29 from the fitting surface side.

Embodiment

Below be used for implementing mode of the present invention based on description of drawings.

[embodiment 1]

For embodiment 1 worm and gear vice mechanism and use its driven steering device, describe in conjunction with Fig. 1～Figure 17.

As shown in Figure 1, driven steering device 10 comprises: the steering system 20 from the steering wheel 21 of vehicle to the steering wheel 29,29 (for example front-wheel) of vehicle; This steering system 20 is applied the assist torque mechanism 40 of assist torque.

Steering system 20 comprises: steering wheel 21; Through steering shaft 22 and universal shaft coupling 23,23 and the pinion shaft 24 (input shaft 24) that links of this steering wheel 21; Through the rack shaft 26 of rack and pinion structure 25 with these pinion shaft 24 links; Through about connecting

rod

27,27 and joint 28,28 and the two ends of this rack shaft 26 link about steering wheel 29,29.

Rack and pinion structure 25 comprises: at the small gear 31 of pinion shaft 24 formation; Tooth bar 32 in rack shaft 26 formation.

According to steering system 20, by the driver steering wheel 21 is carried out steering, by this steering torque and through rack and pinion structure 25 and about connecting

rod

27,27 can to about steering wheel 29,29 carry out steering.

Assist torque mechanism 40 comprises: steering torque sensor 41, control device 42, electric motor 43, worm and gear vice mechanism 44.Steering torque sensor 41 detects the steering torque of the steering system 20 that puts on steering wheel 21.That is, this steering torque sensor 41 is that the torque that puts on pinion shaft 24 is detected, and as the sensor that the torque testing signal is exported, for example is made of magnetostrictive torque sensor or torsion bar type torque sensor.Control device 42 produces control signal based on the torque testing signal of steering torque sensor 41.Electric motor 43 produces and the corresponding motor torque of described steering torque (assist torque) based on the control signal of control device 42.Worm and gear vice mechanism 44 passes to pinion shaft 24 with the assist torque that electric motor 43 produces.This assist torque is delivered to rack and pinion structure 25 from pinion shaft 24.

According to driven steering device 10, applied the compound torque of the assist torque of electric motor 43 by the steering torque the driver, can carry out steering by 26 pairs of steering wheels 29 of rack shaft, 29.

As shown in Figure 2, housing 51 extends in overall width direction (left and right directions of Fig. 2), and accommodates rack shaft 26 and make it in the axial direction slidably.Through ball-joint 52,52 connecting

rod

27,27 is linked to rack shaft 26 from the outstanding length direction two ends of housing 51.

As shown in Figure 3, driven steering device 10 is accommodated in housing 51 with pinion shaft 24, rack and pinion structure 25, steering torque sensor 41 and worm and gear vice mechanism 44, and the upper opening of housing 51 is stopped up by upper lid section 53.Steering torque sensor 41 is installed on upper lid section 53.

Housing 51 is rotatable through three bearings 55～57 with top, length central part and the lower end bearing of the pinion shaft 24 of upper downward-extension, and also possesses rack guide 70.

Rack guide 70 is the pressing mechanisms that are made of guide portion 71 and adjustment bolt 73, and wherein guide portion 71 is adjusted bolt 73 and pressed this guide portion 71 across Compress Spring 72 from being connected to rack shaft 26 with tooth bar 32 opposition sides.

As shown in Figure 4, electric motor 43 possesses horizontal motor drive shaft 43a, and is installed in housing 51.Motor drive shaft 43a is in housing 51 interior extensions, and is linked to worm shaft 46 by shaft coupling 45.Housing 51 is rotatable by bearing 47, the 48 two end part supportings with horizontally extending worm shaft 46.

As shown in Figures 3 and 4, worm and gear vice mechanism 44 is the assist torque transfer mechanism that the assist torque that electric motor 43 produces is passed to pinion shaft 24, i.e. boosting mechanism.In detail, worm and gear vice mechanism 44 comprises: worm screw 80; Transmission of torque worm gear 90 with these worm screw 80 engagements; At the auxiliary worm wheel 100 of this transmission of torque with worm gear 90 settings.Auxiliary worm wheel 100 is the auxiliary gears that arrange with the backlash between the worm gear 90 for removing worm screw 80 and transmission of torque.Below, transmission of torque suitably is called " transmitting with wheel 90 " with worm gear 90, auxiliary worm wheel 100 suitably is called " auxiliary wheel 100 ".

Worm screw 80 is integrally formed with worm shaft 46.Transmit with wheel 90 and be installed on pinion shaft 24.Transmit the worm screw 80 that is engaged in driving side with wheel 90 by making, thus can be from worm screw 80 through transmitting with wheel 90 to the load transfer torque.

Fig. 5 only represents the left-half of worm and gear vice mechanism 44 corresponding to Fig. 3.Such as Fig. 5～shown in Figure 8, transmitting with taking turns 90 is gears of the integrally formed product that are made of hub portion 91 cylindraceous and discoid wheel body 92, and wherein hub portion 91 can be embedded in pinion shaft 24, and wheel body 92 is integrally formed at the outer peripheral portion of this hub portion 91.At the outer circumferential face of wheel body 92, spread all over all-round a plurality of teeth 93 that are formed with.Such transmission comprises a plurality of teeth 93 at least with wheel 90, and wheel body 92 is made of the formed article of resin.For example, this transmission consists of with the formed article of wheel 90 integral body by resin.Perhaps, this transmission is made of metallic material with wheel 90 hub portion 91, and wheel body 92 is made of the formed article of resin.Need to prove, this transmits with the method for wheel 90 except making by molding die, can also be by such as making based on the cutting of the cutting tools such as hobboing cutter.

This transmission is restricted with relative moving axially with wheel 90 and relatively rotates the mode that is restricted and is incorporated into pinion shaft 24.For example, hub portion 91 is incorporated into pinion shaft 24 by spline combination or sawtooth.This transmits with the rotation centerline CL of wheel 90 consistent with the axis of pinion shaft 24.

Such as Fig. 5～shown in Figure 8, transmit with take turns 90 and auxiliary wheel 100 be arranged in row along rotation centerline CL.The rotation centerline of auxiliary wheel 100 (center) is identical with the rotation centerline CL that transmits with wheel 90.Auxiliary wheel 100 overlaps with the face 94 (side's of wheel body 92 face 94) of transmission with a side of wheel 90, and is mounted in the relative mode that all is restricted with this two aspect of relative rotation that moves axially.This auxiliary wheel 100 is than the parts that transmit with the thin ring-type of wheel 90.Outer circumferential face at this auxiliary wheel 100 spreads all over all-round a plurality of teeth 103 that are formed with.The number of teeth of this tooth 103 is identical with the number of teeth of transmitting the tooth 93 of using wheel 90.

And then auxiliary wheel 100 comprises that a plurality of tooth 103 integral body are formed by resin integrated.Therefore, can improve the productivity of auxiliary wheel 100.

At this, as follows definition.As shown in Figure 6, with the face 94 that transmits with a side of wheel 90, the face 94 that namely overlaps auxiliary wheel 100 is called " transmitting the fitting surface 94 with wheel 90 ".With a side's of auxiliary wheel 100 face 104, namely coincide with the face 104 that transmits with taking turns 90 and be called " fitting surface 104 of auxiliary wheel 100 ".With the opposing party's of auxiliary wheel 100 face 105, namely the face with fitting surface 104 opposition sides is called " the non-fitting surface 105 of auxiliary wheel 100 ".

Such as Fig. 5～shown in Figure 8, auxiliary wheel 100 is a kind of like this members: it overlaps with wheel 90 with transmission, and by arranging at mutual fitting surface 94,104 at least 1, preferred 110 location, positioning part of a plurality of (among the embodiment 1 being 3), thereby be mounted.Each positioning part 110 is made of location receiving portion 111 and positioning convex portion 112.This positioning convex portion 112 can embed location receiving portion 111, and is made of the pin of circular section.This location receiving portion 111 is made of recess.The diameter of this location receiving portion 111 is slightly larger than the diameter of positioning convex portion 112.

Location receiving portion 111 is formed at the either party who transmits with the fitting surface 104 of the fitting surface 94 of wheel 90 and auxiliary wheel 100.Positioning convex portion 112 is formed at the opposing party that appoints who transmits with the fitting surface 104 of the fitting surface 94 of wheel 90 and auxiliary wheel 100.In embodiment 1, location receiving portion 111 is formed at the fitting surface 104 of auxiliary wheel 100, and positioning convex portion 112 is formed at the fitting surface 94 that transmits with wheel 90.

Fig. 9 represents to observe from non-fitting surface 105 sides the figure of auxiliary wheel 100.Figure 10 represents to observe auxiliary wheel 100 from fitting surface 104 sides.Figure 11 (a) expression will launch along Zhou Fangxiang take rotation centerline CL as benchmark from positioning part 110, claw section 121 and the hooking part 131 of seeing.The sectional drawing of the relation of the claw section 121 shown in Figure 11 (a) and hooking part 131 is observed in Figure 11 (b) expression from the side.The sectional drawing of the positioning part 110 shown in Figure 11 (a) is observed in Figure 11 (c) expression from the side.

Such as Fig. 7～shown in Figure 11, one side's at receiving portion 111 places, a plurality of location fitting surface 104, namely the fitting surface 104 of auxiliary wheel 100 has take rotation centerline CL as benchmark at least 1, the preferred circular-arc elongated slot 113 of a plurality of (being 3 among the embodiment 1).This elongated slot 113 all is arranged on the concentric circle take rotation centerline CL as benchmark.Each locates the part that receiving portion 111 lays respectively at elongated slot 113.The well width of elongated slot 113 is slightly larger than the diameter of positioning convex portion 112.Each positioning convex portion 112 is by embedding each elongated slot 113, locates receiving portion 111 thereby can this elongated slot 113 of an edge move to be positioned on one side.Owing to being consisting of of positioning convex portion 112 displacement by elongated slot 113 guiding, so when with wheel 90 auxiliary wheel 100 being relatively rotated with respect to transmission, it is easy to transmit with the contraposition of wheel 90 and auxiliary wheel 100.

Each positioning convex portion 112 forms the taper that is tapered.That is, each positioning convex portion 112 is when axial section is observed, and front end is compared with root, is little tapered shape.Each elongated slot 113 is open towards fitting surface 104, and take the face of non-fitting surface 105 sides as end 113a.The well width of each elongated slot 113 is matched with the tapering of each positioning convex portion 112 and sets, and the end 113a of groove is tapering shape in a narrow margin.That is, each elongated slot 113 is when axial section is observed, and the end 113a of groove compares with the front end of groove, is little tapered shape.Thus, positioning convex portion 112 easily can be embedded elongated slot 113, the contraposition transfiguration is easy.Need to prove, at least one party in positioning convex portion 112 and the elongated slot 113 gets final product for tapered shape.

Such as Fig. 6～shown in Figure 8, transmit with wheel 90 and have from fitting surface 94 along rotation centerline CL towards at least 1 of auxiliary wheel 100 extensions, preferred a plurality of (the embodiment 1 being 3) claw section 121.Auxiliary wheel 100 has for 1 that locks one or more claw sections 121, preferred a plurality of (embodiment 1 is 3) hooking part 131 at least.Be limited to each hooking part 131 by each claw section 121, use wheel 90 thereby auxiliary wheel 100 is installed in to transmit.

Each claw section 121 comprises: from transmitting the arm 122 that extends towards auxiliary wheel 100 along rotation centerline CL with the fitting surface 94 of taking turns 90; From the front end of this arm 122 along transmitting with the outstanding claw 123 of the fitting surface 94 of wheel 90.This each claw 123 is such as Fig. 5～shown in Figure 7, and is outstanding towards rotation centerline CL from arm 122.

Each hooking part 131 comprises respectively: through hole 132, plane of inclination 134, non-fitting surface 105.This through hole 132 connects auxiliary wheel 100 along rotation centerline CL, and forms circular-arc take this rotation centerline CL as benchmark.This through hole 132 comprises: can insert simultaneously the 1st logical through hole 135 for arm 122 and claw 123; The 2nd through hole 136 that links to each other and only can supply arm 122 to connect with the 1st through hole 135.This plane of inclination 134 is formed at the non-fitting surface 105 of auxiliary wheel 100, and along the edge 133 through hole 132, circular-arc (inner circumference edge 133) that forms at this auxiliary wheel 100.

Shown in Fig. 9 and Figure 11 (b), plane of inclination 134 is take the border 134a of the 1st through hole 135 and the 2nd through hole 136 as the inclination initial point 134a the darkest apart from the non-fitting surface 105 of auxiliary wheel 100, tilt to extend to the non-fitting surface 105 of auxiliary wheel 100 along the 2nd through hole 136 from this inclination initial point 134a, and with the beveled end 134b of this extension as the inclination terminal point 134b that links to each other with non-fitting surface 105.

Claw 123 is following structures: insert with arm 122 lead in the 1st through hole 135 after, by relatively rotating take rotation centerline CL as benchmark with respect to auxiliary wheel 100, thereby be tilted face 134 guiding, simultaneously when being positioned at non-fitting surface 105, as shown in Figure 5, have and flexibly be limited to non-fitting surface 105.

That is, as shown in Figure 6, be configured to slightly less to the thickness T h of non-fitting surface 105 than the fitting surface 104 from auxiliary wheel 100 from transmitting with taking turns 90 the fitting surface 94 height H i to the lower surface 123a (locking surface 123a) of claw 123.Therefore, guide when arriving non-fitting surface 105 while be tilted face 134 at claw 123, auxiliary wheel 100 is along the 2nd through hole 136, simultaneously towards transmitting with taking turns 90 fitting surface 94 to have flexible mode slight curvature.Therefore, claw 123 is limited to non-fitting surface 105 to have flexible mode.

And then such as Fig. 5 and shown in Figure 8, when being limited to non-fitting surface 105, positioning convex portion 112 is the formations that are positioned at location receiving portion 111 at the claw 123 (with reference to Fig. 7) of claw section 121.In detail, such as Fig. 8～shown in Figure 10, each positioning part 110 take rotation centerline CL as benchmark in the circumferential direction of the circle with equidistant arrangement.Each claw section 121 and hooking part 131 also take rotation centerline CL as benchmark in the circumferential direction of the circle with equidistant arrangement.And then all claw sections 121 and all hooking parts 131 are arranged on the concentric circle take rotation centerline CL as benchmark, and compare each positioning part 110 more by rotation centerline CL.

The center P 1 (center P 1 of the circumferencial direction take rotation centerline CL as benchmark) of each the 1st through hole 135 is made as the 1st reference point P1.Each the 1st reference point P1 arranges with equal angles θ 1.The width of the circumferencial direction of each the 1st through hole 135 is set to the width greater than arm 122 and claw 123.

One end of circular-arc elongated slot 113 is positioned at the 1st reference point P1, and the other end is positioned at the 2nd reference point P2.All elongated slots 113 extend to equidirectional from the 1st reference point P1.Be θ 2 from the angle of the 1st reference point P1 to the 2 reference point P2.That is, the scope of elongated slot 113 (length) is angle θ 2.Location receiving portion 111 is positioned at the 2nd reference point P2.The degree of depth of this location receiving portion 111 that is made of recess more preferably is set as larger than the degree of depth of elongated slot 113.

All through holes 132 extend to equidirectional from the 1st reference point P1, and along elongated slot 113.The scope (length) of circular-arc through hole 132 is greater than angle θ 2.The inclination terminal point 134b of plane of inclination 134 compares the 2nd reference point P2 more by the 1st reference point P1.

Below,, describe based on Figure 11～Figure 13 with respect to transmitting with the contraposition of wheel 90 and the order of installation for auxiliary wheel 100.

At first, shown in Figure 11 (b), auxiliary wheel 100 is carried out contraposition transmitting above taking turns 90 fitting surface 94, and make on 135 pairs of the position of claw section 121 and the 1st through holes.At this moment, an end of positioning convex portion 112, elongated slot 113, claw section 121, the 1st through hole 135 all are positioned at the 1st reference point P1.

Need to prove, all be positioned at the example of the 1st reference point P1 although for example understand an end, claw section 121, the 1st through hole 135 of positioning convex portion 112, circular-arc elongated slot 113, but, as long as an end of positioning convex portion 112 and circular-arc elongated slot 113 is positioned at same position, and then claw section 121 and the 1st through hole 135 are positioned at same position and get final product.That is, the position of an end of positioning convex portion 112 and circular-arc elongated slot 113 can not be the position identical with the 1st through hole 135 with claw section 121.

Below, auxiliary wheel 100 is coincided with the fitting surface 94 that transmits with wheel 90 rotate towards the 2nd reference point P 2 simultaneously.The stage as shown in figure 12 in its way.

Figure 12 represents corresponding to Figure 11, the stage in the expression assembling way.Figure 12 (a) expression positioning convex portion 112 and the state of claw section 121 from the 1st reference point P1 to the 2nd reference point P2 displacement.The sectional drawing of the relation of the claw section 121 shown in Figure 12 (a) and hooking part 131 is observed in Figure 12 (b) expression from the side.The sectional drawing of the positioning part 110 shown in Figure 12 (a) is observed in Figure 12 (c) expression from the side.

Shown in Figure 12 (a), (b), claw 123 joins with plane of inclination 134.Further with respect to transmitting with wheel 90 auxiliary wheel 100 is rotated to the 2nd reference point P2 from this state.Consequently, claw 123 is tilted face 134 guiding and to the non-fitting surface 105 side displacements of auxiliary wheel 100.Therefore, auxiliary wheel 100 approaches the fitting surface 94 that transmits with wheel 90, coincides with at last fitting surface 94.Afterwards, with respect to transmitting with taking turns 90 auxiliary wheel 100 further rotated to the 2nd reference point P2.Consequently, claw 123 arrives the 2nd reference point P2.Its assembling terminal stage as shown in figure 13.

Figure 13 represents corresponding to Fig. 8 and Figure 12, expression assembling terminal stage.Figure 13 (a) expression positioning convex portion 112 and claw section 121 arrive the state of the 2nd reference point P2.The sectional drawing of the relation of the claw section 121 shown in Figure 13 (a) and hooking part 131 is observed in Figure 13 (b) expression from the side.The sectional drawing of the positioning part 110 shown in Figure 13 (a) is observed in Figure 13 (c) expression from the side.

Such as Fig. 8 and shown in Figure 13, claw 123 is limited to non-fitting surface 105 by arriving the 2nd reference point P2.At this moment, positioning convex portion 112 is located receiving portion 111 by being positioned at the 2nd reference point P2 thereby embed.At this moment, produce the vibration of following embedding or embed sound in the moment that embeds, do not finish even the assembling operation person does not see also can confirm to assemble.So far, auxiliary wheel 100 is finished with respect to the contraposition and the installation exercise that transmit with wheel 90.That is, by making auxiliary wheel 100 relatively rotate angle θ 2 (rotational angle theta 2) with respect to transmitting with taking turns 90, thereby can take turns 90,100 each other contraposition and assemblings.

So, by transmitting with wheel 90 coincidence auxiliary wheels 100, embed positioning convex portion 112 in location receiving portion 111, thereby can transmit with taking turns 90 location, auxiliary wheel 100 being installed.Therefore, as shown in Figure 4, by embedding positioning convex portion 112 in location receiving portion 111, thus can be with the tooth 103 of auxiliary wheel 100 with respect to transmitting the position that easily be set in the best with the relative position of the tooth 93 of wheel 90.By will be so mutually integrated respectively take turns and 90,100 be assembled on the worm screw 80, thereby worm screw 80 and transmit the sense of rotation (setting of preload) of being pushed in advance to auxiliary wheel 100 with at least one party who takes turns 90.

And then location receiving portion 111 is positioned at the part take the rotation centerline CL of auxiliary wheel 100 as the circular-arc elongated slot 113 of benchmark.Therefore, after circular-arc elongated slot 113 has embedded positioning convex portion 112, rotate take rotation centerline CL as benchmark by the either party that will transmit with wheel 90 and auxiliary wheel 100, thus the location receiving portion 111 chimeric positioning convex portion 112 that are being positioned at elongated slot 113.The worker can be in the situation that not visual, and the tooth 103 of auxiliary wheel 100 is set on the position of the best reliably and easily with respect to the relative position that transmits with the tooth 93 of wheel 90.Therefore, can reduce assembling number in man-hour.

And then, by transmitting with wheel 90 coincidence auxiliary wheels 100, lock claw sections 121 at hooking part 131.Consequently, can reliably and easily assemble auxiliary wheel 100 with wheel 90 in transmission.Auxiliary wheel 100 after the assembling is used in the axial direction invariant position of wheel 90 with respect to transmitting, and keeps stable assembled state.

And then, arm 122 and claw 123 inserted lead in the 1st through hole 135 after, by relatively rotating take rotation centerline CL as benchmark with respect to auxiliary wheel 100, thereby Yi Bian claw 123 is tilted face 134 guiding, Yi Bian be positioned at the non-fitting surface 105 of auxiliary wheel 100.Consequently, claw 123 has and flexibly is limited to non-fitting surface 105.So, only by with respect to transmitting with wheel 90 auxiliary wheel 100 being overlapped, and carry out the operation of relative rotation, just can with taking turns on 90 auxiliary wheel 100 be installed integratedly in transmission, so assembling performance is good.

And then when claw 123 was limited to non-fitting surface 105, positioning convex portion 112 was embedded in location receiving portion 111.Only by with respect to transmitting with wheel 90 auxiliary wheel 100 being overlapped, and carry out the operation of relative rotation, thereby can auxiliary wheels 100 be installed transmitting with wheel 90, and with the tooth 103 of auxiliary wheel 100 with respect to transmitting the position that reliably and easily is set in the best with the relative position of the tooth 93 of wheel 90.Therefore, assembling performance is good.

But such as Fig. 5～shown in Figure 7, transmitting with worm gear 90 and arm 122 and claw 123 is products formeds by the resin integrated shaping.Claw 123 is outstanding towards rotation centerline CL from arm 122.Therefore, as shown in figure 14, can be set as 2 cut piece along rotation centerline CL, i.e. upper die tooling 141 and bed die 142 with the molding die 140 of taking turns 90 with being used for shape transfer.Therefore, can improve the productivity of transmitting with wheel 90.

Below, describe based on Figure 15 for worm screw 80 and the meshing relation that transmits with wheel 90 and auxiliary wheel 100.

Figure 15 (a) represents from the side, is observing worm screw 80 shown in Figure 4 and transmit the meshing relation of using wheel 90 and auxiliary wheel 100 to sight line 15 directions of Fig. 4.Need to prove, in Figure 15 (a), represented to transmit with wheel 90 by notional line.In addition, for auxiliary wheel 100, only represent tooth 103.

Figure 15 (b) is the b-b line sectional drawing of Figure 15 (a).Figure 15 (c) is the c-c line sectional drawing of Figure 15 (a), and the section along facewidth direction centre line L w that expression is transmitted with wheel 90 consists of.Figure 15 (d) is the d-d line sectional drawing of Figure 15 (a), and expression is along the section formation of transmitting with the fitting surface 94 of wheel 90.

Shown in Fig. 4 and Figure 15 (a), worm screw 80 and to transmit with the shaft angle (crossing angle) of taking turns 90 be not 90 °, but " 90 ° ± β ° ".At this, angle beta is called " skew angle β ".Therefore, the engagement line WL of worm and gear vice mechanism 44 (the rotation centerline WL of worm screw 80) has from transmitting axial plane (transmitting with the facewidth direction centre line L w that takes turns 90) with wheel 90 for general worm and gear vice mechanism ± inclination of β °.Therefore, do not transmitting on the same axial plane of using wheel 90 with worm screw 80 contact pointss separately that mesh, that transmit the tooth 93 of using wheel 90.Such worm and gear vice mechanism 44 is so-called " oblique axis worm and gear vice mechanisms ".

Worm screw 80 is fabricated metalss, such as the steel product of mechanical realization with carbon steel steel (JIS-G-4051) etc.On the other hand, for transmitting with wheel 90, comprise at least a plurality of teeth 93, wheel body 92 is resins of nylon resin etc.In addition, auxiliary wheel 100 is resins of nylon resin etc.Owing to meshing the wheel 90,100 of resins the worm screw 80 of fabricated metals, therefore can make engagement rounder and more smooth, and can further reduce noise.And then worm screw 80 is owing to being fabricated metals, and rigidity is large, is difficult to resiliently deformable.With respect to this, wheel 90,100 so rigidity is less, is compared worm screw 80 easy resiliently deformables owing to being resin.

The tooth 93, the 103rd of wheel 90,100, " flat tooth ".Therefore, when carrying out resin forming, can carry out simply withdrawing pattern.

Shown in Figure 15 (b), the D outer diameter a of auxiliary wheel 100 sets greatlyr than the D outer diameter t that transmits with wheel 90.In detail, transmit with take turns 90 be positioned at worm screw 80 positive side and with its engagement.The tooth 103 of auxiliary wheel 100 along transmit with the fitting surface 94 of taking turns 90 extend to worm screw 80 directly over, intermeshing directly over worm screw 80.

The tooth top part of this tooth 103 (compare to transmit and use the more part of radius vector foreign side extension of wheel 90) is outstanding towards the top of worm shaft 46, and other part depression, such as Fig. 5 and shown in Figure 6, outstanding lower end surface 103u is consistent with the height of the fitting surface 104 of auxiliary wheel 100.That is, the facewidth of the tooth top of tooth 103 part is identical to the thickness T h of non-fitting surface 105 with fitting surface 104 from auxiliary wheel 100.Since so at tooth 103 depressed part 103d (with reference to Fig. 6) being set, thus when tooth 103 is crooked to the sense of rotation of auxiliary wheel 100, can not join with the fitting surface 94 that transmits with wheel 90, can be crooked sleekly.

Shown in Figure 15 (a), the worm tooth 81 of worm screw 80 (that is, tooth 81) is for example with 1 setting, and the spacing setting of worm tooth 81 is certain.The profile of tooth of the tooth 81 of worm screw 80 and to transmit with the profile of tooth of taking turns 90 tooth 93 are open forms or roughly trapezoidal gradually.With respect to gradually open form or the roughly profile of tooth of trapezoidal worm screw 80, form the identical shaped generate cutting of carrying out by the profile of tooth that will transmit with wheel 90, thereby can obtain transmitting the profile of tooth with wheel 90.With respect to the pressure angle of the tooth 81 of worm screw 80, transmit with the pressure angle of the tooth 93 of wheel 90 identical.

As shown in Figures 7 and 8, the profile of tooth of the tooth 103 of auxiliary wheel 100 is roughly profiles of tooth of certain substantially planar of transverse tooth thickness.That is, the transverse tooth thickness of the tooth root of the tooth 103 of auxiliary wheel 100 is slightly larger than the transverse tooth thickness of increment.And " tooth depth " of this tooth 103 (radius of a circle direction distance at the bottom of top circle and the tooth) is greater than " tooth depth " transmitted with the tooth 93 of wheel 90.Therefore, the tooth 103 of auxiliary wheel 100 is compared with the tooth 93 that transmits with wheel 90, easily to transverse tooth thickness direction (sense of rotation of auxiliary wheel 100) resiliently deformable.In addition, therefore the profile of tooth of the tooth 103 of auxiliary wheel 100, is not easy therefore can prevent staggering of axial engagement in axially (rotation centerline CL direction) distortion owing to being rectangular roughly when radially observing, meshes and stablize.

So, all teeth 103 of auxiliary wheel 100 constitute the bending deflection that can have " spring performance " to the sense of rotation (positive veer and this two side of reverse direction) of auxiliary wheel 100.The spring performance of so-called tooth 103 refers to: reach in the loading that puts on tooth 103 on the amount of bow of the tooth 103 that is produced by this loading, have predefined certain characteristic (tooth 103 self has " function of spring ").That is, tooth 103 has the function equal with leaf spring.

Such auxiliary wheel 100 similarly is the outer circumferential face with respect to rotatable disk, and being arranged with can be to the such member of a large amount of leaf springs of the sense of rotation resiliently deformable of disk.This a large amount of leaf spring plays the effect of the tooth 103 of auxiliary wheel 100.

At this, take turns 90,100 meshing relation in order easily to understand worm screw 80 and each, for worm tooth 81 and tooth 93,103, illustrate as following for convenient.

Shown in Figure 15 (a), (c), (d), although actual worm tooth 81 is continuous spiral helicine teeth, but herein for convenient, will be called in turn to the left the 1st tooth 81a, the 2nd tooth 81b, the 3rd tooth 81c from the figure right side with 3 teeth 81 that the tooth 93 of taking turns 90 meshes with transmission.

Shown in Figure 15 (a), (c), in a plurality of teeth 93 that transmit with wheel 90, will be called in turn to the left the 1st tooth 93a, the 2nd tooth 93b, the 3rd tooth 93c from the figure right side with 3 teeth 93 of worm tooth 81 engagements.

In addition, shown in Figure 15 (a), (d), in a plurality of teeth 103 of auxiliary wheel 100, will be called in turn to the left the 1st tooth 103a, the 2nd tooth 103b, the 3rd tooth 103c from the figure right side with 3 teeth 103 of worm tooth 81 engagements.The phase place of the 1st tooth 103a is corresponding to the phase place of transmitting with the 1st tooth 93a of wheel 90.The phase place of the 2nd tooth 103b is corresponding to the phase place of transmitting with the 2nd tooth 93b of wheel 90.The phase place of the 3rd tooth 103c is corresponding to the phase place of transmitting with the 3rd tooth 93c of wheel 90.

A plurality of teeth 103 of auxiliary wheel 100 constitute the bending deflection that can have to the sense of rotation of auxiliary wheel 100 " spring performance ".Therefore, each tooth 103 can and transmit the sense of rotation that push auxiliary wheel 100 with at least one party who takes turns 90 to worm screw 80 thus by joining with the tooth 81 of worm screw 80 under the state of the sense of rotation bending of auxiliary wheel 100.That is, a plurality of teeth 103 are can make worm screw 80 and transmit the formation of rotating with at least one party who takes turns 90.In detail, at least one of a plurality of teeth 103 of auxiliary wheel 100 is all the time to join to the state of the sense of rotation bending of auxiliary wheel 100 and the tooth 81 of worm screw 80.

For example, now as Figure 15 (a), (c) shown in, the flank of tooth that transmits with the right side of the 1st tooth 81a of the flank of tooth in the left side of taking turns 90 the 1st tooth 93a and worm screw 80 joins.At this moment, transmit with take turns 90 other tooth 93, namely the 2nd tooth 93b and the 3rd tooth 93c do not join with the worm tooth 81 of worm screw 80.

Under this engagement, shown in Figure 15 (a), (d), the flank of tooth on the right side of the 3rd tooth 103c of auxiliary wheel 100 joins with the flank of tooth in the left side of the 2nd tooth 81b of worm screw 80 in resiliently deformable.At this moment, auxiliary wheel 100 other tooth 103, namely the 1st tooth 103a and the 2nd tooth 103b do not join with the worm tooth 81 of worm screw 80.

So, by transmitting the worm tooth 81 that sandwiches in the axial direction worm screw 80 with the 3rd tooth 103c that takes turns 90 the 1st tooth 93a and auxiliary wheel 100.Therefore, join with worm screw 80 under the state of a plurality of tooth 103 left-hand tools direction bendings, thus, worm screw 80 and transmission are pushed to the sense of rotation of auxiliary wheel 100 with at least one party of wheel 90.Consequently, can remove the 1st tooth 81a of worm screw 80 and transmitting with the backlash δ (gap delta) between the 1st tooth 93a of wheel 90.That is, can remove the tooth 81 of worm screw 80 and transmitting with the backlash δ between the tooth 93 of wheel 90.

Under this engagement shown in Figure 15, when making worm screw 80 forwards (to arrow R1 direction rotation), each takes turns 90,100 forwards (to arrow Ra direction rotation).Tooth 81 and the transmission of worm screw 80 are kept the engagement that does not have above-mentioned backlash δ with the tooth 93 of wheel 90.

Figure 16 (a) represents corresponding to Figure 15 (c).Figure 16 (b) represents corresponding to Figure 15 (d).The situation of not joining with the tooth 81 of worm screw 80 fully with taking turns 90 tooth 93 is transmitted in Figure 16 (a) expression.In this case, at the 1st tooth 81a of worm screw 80 and transmit between the 1st tooth 93a with wheel 90, and at the 1st tooth 81a of worm screw 80 with transmit with taking turns between 90 the 2nd tooth 93b and have backlash δ.But shown in Figure 16 (b), at least one of a plurality of teeth 103 of auxiliary wheel 100, namely the 3rd tooth 103c is joining with the 2nd tooth 81b of worm screw 80 under the state of the sense of rotation bending of auxiliary wheel 100.

Therefore, transmitting before tooth 81 with the tooth 93 of wheel 90 and worm screw 80 joins at least, at least one of a plurality of teeth 103 of auxiliary wheel 100 joined with the tooth 81 of worm screw 80 under the state of the sense of rotation bending of auxiliary wheel 100.That is, at least one of a plurality of teeth 103 is with worm screw 80 with transmit with at least one party who takes turns 90 and push described sense of rotation to.Consequently, can reduce reliably the tooth 81 of worm screw 80 and the impact of transmitting the backlash between the tooth 93 of using wheel 90.

Figure 17 (a) represents corresponding to Figure 15 (c).Figure 17 (b) represents corresponding to Figure 15 (d).When worm screw 80 was switched to reverse shown in Figure 17 (to arrow R2 direction rotation) from forward state shown in Figure 15, each was taken turns 90,100 and reverses (to arrow Rb direction rotation).Consequently, the 1st tooth 81a of worm screw 80 switches to shown in Figure 17 (a) and (joining) state the 2nd tooth 93b engagement from shown in Figure 15 (c) and (joining) state the 1st tooth 93a engagement.But at the time point of this switching, shown in Figure 17 (b), the 3rd tooth 103c of auxiliary wheel 100 still joins with the 2nd tooth 81b of bent state and worm screw 80.

So, by worm screw 80 is switched from just turning to reverse, thereby before being about to switch to reverse direction from from the transmission of worm screw 80 engagements with take turns 90 the 1st tooth 93a to be engaged in the 2nd tooth 93b different with the 1st tooth 93a during, the 3rd tooth 103c of auxiliary wheel 100 is joining with tooth 81 under the state of the sense of rotation bending of auxiliary wheel 100.Therefore, when the sense of rotation of worm screw 80 was switched from positive veer to reverse direction, the tooth 81 of the worm screw 80 of reverse was contacted with the tooth 93 that transmits with wheel 90 lentamente.Can suppress

tooth

81,93 and touch each other the generation of the sound of cramping that causes.

From the above description, at least one of a plurality of teeth 103 of auxiliary wheel 100 joined with the tooth 81 of worm screw 80 under the state of the sense of rotation bending of auxiliary wheel 100 all the time.Therefore, worm screw 80 with between transmitting with wheel 90, when the transmission that does not have torque, at least one of a plurality of teeth 103 pushed worm screw 80 to described sense of rotation with at least one party who transmits with wheel 90.

For example, when not using wheel 90 transmitting torque from worm screw 80 to transmission, transmit with taking turns 90 under external force reverses, sometimes with worm screw 80 touchings.But a plurality of teeth 103 of auxiliary wheel 100 are joining with the tooth 81 of worm screw 80 under the state of the sense of rotation bending of auxiliary wheel 100.Therefore, the transmission of reverse with wheel 90 tooth 93 can with tooth 81 collisions of worm screw 80, can touch lentamente and mesh.The generation of the sound of cramping that can prevent

tooth

81,93 from touching each other and cause.And then, when not using wheel 90 transmitting torque from worm screw 80 to transmission, continue to suppress transmission by the tooth 103 with spring performance and use wheel 90 to reverse under external force.Therefore, can reduce reliably the tooth 81 of worm screw 80 and the impact of transmitting the backlash between the tooth 93 of using wheel 90.

And then, even if because of the long-term worm and gear vice mechanism 44 of using, the tooth 81 of worm screw 80 or transmit tooth 93 wearing and tearing with wheel 90, in the situation that backlash will increase, a plurality of teeth 103 of auxiliary wheel 100 are also joining with the tooth 81 of worm screw 80 under the state of the sense of rotation bending of auxiliary wheel 100.Therefore, do not need the adjustment operation of backlash.

Sum up above explanation, as described below.

Worm and gear vice mechanism 44 by worm screw 80, be used for transmission at transmitting torque between this worm screw 80 and the load with wheel 90 and be used for reducing the tooth 81 of worm screw 80 and transmit with the auxiliary wheel 100 of taking turns the backlash between 90 the tooth 93 consisting of.Therefore, as long as transmit with wheel 90 owing to having the function of transmitting torque, therefore can easily design to have enough intensity.Consequently, can easily improve the durability of worm and gear vice mechanism 44.

And then a plurality of teeth 103 of auxiliary wheel 100 constitute the bending deflection that can have to the sense of rotation of auxiliary wheel 100 " spring performance ".Have spring performance and bending deformed a plurality of tooth 103 by under the state of described sense of rotation bending, joining with worm screw 80, thereby with worm screw 80 with transmit with at least one party who takes turns 90 and push described sense of rotation to.Consequently, can reduce the tooth 81 of worm screw 80 and transmitting with the backlash between the tooth 93 of wheel 90.

So, a plurality of teeth of auxiliary wheel 100 103 self can bending deflection owing to having spring performance, does not therefore need be used to the other member that reduces backlash.Therefore, the formation that has reduced the worm and gear vice mechanism 44 of backlash can be simplified, can reduce number of spare parts, and can reduce assembling number in man-hour.

And then, in driven steering device 10, power transmission mechanism as the torque that electric motor 43 is produced is transmitted to steering system 20 has adopted the worm and gear vice mechanism 44 of removing backlash, therefore can further improve the durability of power transmission mechanism 44.

And then, by removing the backlash of worm and gear vice mechanism 44, the generation of the sound of cramping each other of the

tooth

81,93 in the time of can further suppressing steering dish 21.Consequently, can further reduce the indoor noise of car.For example, when the craspedodrome of vehicle is travelled, not from worm screw 80 to transmitting with wheel 90 transmitting torques.Under this travelling state, can suppress to be subject to as far as possible vehicle the vibration of travelling impact and produce the sound of cramping so that tooth is touched each other.

And then, by removing the backlash of worm and gear vice mechanism 44, can keep and transmit with the wheel 90 good engagements with respect to worm screw 80.Therefore, when steering wheel 21 being returned the wheel operation, can suppress 20 generations of transmitting the time lag of assist torque from worm and gear vice mechanism 44 to steering system.And then, owing to having removed backlash, so in the situation that make by worm screw 80 and to transmit with wheel 90 rotations,

tooth

81,93 can not collide each other, but touch lentamente and mesh, therefore can make steering wheel 21 to return the wheel start good.Therefore, can further improve the steering sensation (steering feeling) of driven steering device 10.

[embodiment 2]

For embodiment 2 worm and gear vice mechanism and use its driven steering device, describe based on Figure 18～Figure 21.Figure 18 represents corresponding to above-mentioned Fig. 5.Figure 19 represents corresponding to above-mentioned Fig. 6.Figure 20 represents corresponding to above-mentioned Fig. 7.Figure 21 represents corresponding to above-mentioned Fig. 8.

Embodiment 2 worm and gear vice mechanism 44A and use its driven steering device 10A to be characterised in that, change the configuration relation of the positioning part 110 of above-mentioned Fig. 5～shown in Figure 8, claw section 121, hooking part 131 into the embodiment's 1 of Figure 18～shown in Figure 21 positioning part 110A, the configuration relation of the 121A of claw section, hooking part 131A, for other formation, because identical with the formation of above-mentioned Fig. 1～shown in Figure 17, description thereof is omitted.

Specifically, embodiment 2 worm and gear vice mechanism 44A comprises: worm screw 80, with the transmission of torque of this worm screw 80 engagements with worm gear 90A and the auxiliary worm wheel 100A that arranges with worm gear 90A in this transmission of torque.Transmission of torque with worm gear 90A (transmit with wheel 90A) be in fact with the transmission of above-described embodiment 1 with the identical formation of worm gear 90, be the gear of the integrally formed product that consist of by the hub portion 91A of tubular and at the integrally formed discoid wheel body 92A of the outer peripheral portion of hub portion 91A.Auxiliary worm wheel 100A (auxiliary wheel 100A) is identical with the auxiliary wheel 100 of above-described embodiment 1 in fact formation.

At least 1, preferably a plurality of (among the embodiment 2 being 3) positioning part 110A is identical with the positioning part 110 of above-described embodiment 1 in fact formation, consisted of by location receiving portion 111A and positioning convex portion 112A.A plurality of location receiving portion 111A are identical with a plurality of location receiving portion 111 of above-described embodiment 1 in fact formations, are formed at the fitting surface 94 that transmits with wheel 90A.These a plurality of location receiving portion 111A are positioned at the part of a plurality of elongated slot 113A.These a plurality of elongated slot 113A are identical with a plurality of elongated slots 113 of above-described embodiment 1 in fact formations, are formed at the fitting surface 94 that transmits with wheel 90A.A plurality of positioning convex portion 112A are identical with a plurality of positioning convex portion 112 of above-described embodiment 1 in fact formations, are formed at the fitting surface 104 of auxiliary wheel 100A.

At least 1, preferably a plurality of (among the embodiment 1 being 3) 121A of claw section is identical with the claw section 121 of above-described embodiment 1 in fact formation, is formed at the fitting surface 104 of auxiliary wheel 100A.The footpath foreign side of each claw 123 of these a plurality of claw 121A of section from arm 122 to auxiliary wheel 100A is outstanding.

At least 1, preferably a plurality of (among the embodiment 1 being 3) hooking part 131A is identical with the hooking part 131 of above-described embodiment 1 in fact formation, be formed to transmit with wheel 90A.Each plane of inclination 134 of these a plurality of hooking part 131A is along transmitting the circular-arc edge 133A (outer periphery 133A) that uses the through hole 132 of taking turns 90A formation.

At this, as following, define.As shown in figure 19, with the face 94 that transmits with the side of wheel 90A, the face 94 that namely overlaps auxiliary wheel 100A is called " transmitting the fitting surface 94 with wheel 90A ".This is transmitted face 95A with the opposing party of wheel 90A, namely with the face of fitting surface 94 opposite sides in, the face 95A that blocks the locking surface 123a of claw 123 is called " transmitting the non-fitting surface 95A with wheel 90A ".With the side's of auxiliary wheel 100A face 104, namely coincide with the face 104 that transmits with taking turns 90A and be called " fitting surface 104 of auxiliary wheel 100A ".

Height H iA from the fitting surface 104 of auxiliary wheel 100A to the lower surface 123a of claw 123 is set to and is slightly less than from transmitting with the fitting surface 94 of the wheel 90A thickness T hA to non-fitting surface 95A.

According to embodiment 2, play effect, the effect same with effect, the effect of above-described embodiment 1.

[embodiment 3]

For embodiment 3 worm and gear vice mechanism and use its driven steering device, describe based on Figure 22～Figure 26.Figure 22 represents corresponding to above-mentioned Fig. 5.Figure 23 represents corresponding to above-mentioned Fig. 6.Figure 24 represents corresponding to above-mentioned Fig. 7.Figure 25 represents corresponding to above-mentioned Figure 11.Figure 26 represents corresponding to above-mentioned Figure 13.

Embodiment 3 worm and gear vice mechanism 44B and use its driven steering device 10B to be characterised in that, change the embodiment's 1 of above-mentioned Fig. 5～shown in Figure 13 location receiving portion 111 and positioning convex portion 112 into Figure 22～formation that has hooking part 131B and the 121B of claw section concurrently shown in Figure 26, for other formation because identical with the formation of above-mentioned Fig. 1～shown in Figure 17, so description thereof is omitted.

Specifically, embodiment 3 worm and gear vice mechanism 44B is the formation identical with embodiment 1 worm and gear vice mechanism 44.A plurality of claw 121B of section are formations identical with a plurality of claw section 121.A plurality of hooking part 131B have a plurality of recess 131a in non-fitting surface 105 formation of auxiliary wheel 100.All recess 131a are positioned at the 2nd reference point P2, can be chimeric for the locking surface 123a of a plurality of claw 121B of section, and the bottom surface forms smooth.

As shown in figure 23, be set to the thickness T hB that is slightly less than from the fitting surface 104 of auxiliary wheel 100 to recess 131a from transmitting with taking turns 90 the fitting surface 94 height H iB to the locking surface 123a of claw 123.Therefore, as shown in figure 26, while when claw 123 is tilted face 134 guiding and arrives the 2nd reference point P2, have the recess 131a that flexibly is limited to non-fitting surface 105.

So, embodiment's 1 shown in Figure 6 positioning convex portion 112 is made of embodiment 3 the 121B of claw section.In addition, embodiment's 1 shown in Figure 6 location receiving portion 111 is made of embodiment 3 hooking part 131B.Therefore, the 121B of claw section is embedded into and is limited to hooking part 1311B, is restricted to the displacement along the direction of rotation centerline CL.Therefore, auxiliary wheel 100 is positioned and is installed on and transmits with wheel 90.

According to embodiment 3, play effect, the effect same with effect, the effect of above-described embodiment 1.And then according to embodiment 3, the 121B of claw section has both the function of positioning convex portion, and hooking part 131B has both the function of locating receiving portion.Therefore, the location receiving portion 111 and the positioning convex portion 112 that do not need embodiment 1.Therefore, can make auxiliary wheel 100 location and be installed on the formation of transmitting with wheel 90 and simplify.

Need to prove, embodiment 3 formation can also be used in above-described embodiment 2.That is, the 121B of claw section can be formed at auxiliary wheel 100A, and hooking part 131B is formed at transmission with taking turns 90A.

[embodiment 4]

For embodiment 4 worm and gear vice mechanism and use its driven steering device, describe based on Figure 27～Figure 31.Figure 27 represents corresponding to above-mentioned Fig. 5.Figure 28 represents corresponding to above-mentioned Fig. 6.Figure 29 represents corresponding to above-mentioned Fig. 7.Figure 30 represents corresponding to above-mentioned Fig. 9.Figure 31 represents corresponding to above-mentioned Figure 10.

Embodiment 4 worm and gear vice mechanism 44C and use its driven steering device 10C to be characterised in that, above-mentioned Fig. 3～auxiliary worm wheel 100 shown in Figure 17 is changed into the formation of the auxiliary worm wheel 100C of Figure 27～shown in Figure 31, for other formation, since identical with the formation of above-mentioned Fig. 1～shown in Figure 17, so description thereof is omitted.

Specifically, embodiment 4 worm and gear vice mechanism 44C comprises: worm screw 80, with the transmission of torque of this worm screw 80 engagements with worm gear 90C and the auxiliary worm wheel 100C that arranges with worm gear 90C in this transmission of torque.

Transmission of torque is identical with embodiment 1 transmission usefulness worm gear 90 in fact formation with worm gear 90C (transmit with wheel 90C), is the gear of the integrally formed product that consist of by the hub portion 91C of tubular with at the integrally formed discoid wheel body 92C of the outer peripheral portion of this hub portion 91C.Outer circumferential face at this wheel body 92C spreads all over all-round a plurality of teeth 93 that are formed with.Such transmission comprises a plurality of teeth 93 at least with wheel 90C, and wheel body 92C is made of the formed article of resin.

Auxiliary worm wheel 100C (auxiliary wheel 100C) is the auxiliary gear that arranges with the backlash between the worm gear 90C in order to remove worm screw 80 and transmission of torque.Below, auxiliary worm wheel 100C suitably is called " auxiliary wheel 100C ".

Transmit with wheel 90 and auxiliary wheel 100C and be arranged in row along rotation centerline CL.The rotation centerline of auxiliary wheel 100C (center) is identical with the rotation centerline CL that transmits with wheel 90.Auxiliary wheel 100C is than the parts that transmit with the thin ring-type of wheel 90C, and when being coincided with the face 94C (side's of wheel body 92C face 94C) of transmission with the side of wheel 90C, relative moving axially with this two side of relative rotation is restricted and is mounted.

This auxiliary wheel 100C is the gear of the integrally formed product that consist of of the wheel body 101c by the force application part 101b of discoid hub portion 101a, ring-type and ring-type, wherein hub portion 101a overlaps to be installed on and transmits with wheel 90C, force application part 101b is integrally formed at the outer peripheral portion of this hub portion 101a, and wheel body 101c is integrally formed at the outer peripheral portion of this force application part 101b.

At this, as follows definition.As shown in figure 28, with the face 94C that transmits with the side of the hub portion 91C that takes turns 90C, the face 94C that namely overlaps auxiliary wheel 100C is called " transmitting the fitting surface 94C with wheel 90C ".Face 104C with the side of the hub portion 101a of auxiliary wheel 100C namely coincides with the face 104C that transmits with taking turns 90C and is called " the fitting surface 104C of auxiliary wheel 100C ".With the opposing party's of the hub portion 101a of auxiliary wheel 100C face 105C, namely the face 105C of the opposition side of fitting surface 104C is called " the non-fitting surface 105C of auxiliary wheel 100C ".

Such as Figure 28～shown in Figure 31, auxiliary wheel 100C is that a kind of coinciding with transmitted with wheel 90C, and by at least 1 that arranges at mutual

fitting surface

94C, 104C, preferably 110 location, a plurality of (among the embodiment 4 being 3) positioning part, the member installed.Positioning part 110 is formations identical with the embodiment's 1 of Fig. 5～shown in Figure 11 positioning part 110, is made of location receiving portion 111 and positioning convex portion 112.

Location receiving portion 111 is formed at the either party who transmits with the fitting surface 104C of the fitting surface 94C that takes turns 90C and auxiliary wheel 100C.Positioning convex portion 112 is formed at the opposing party who transmits with the fitting surface 104C of the fitting surface 94C that takes turns 90C and auxiliary wheel 100C.In embodiment 4, location receiving portion 111 is formed at the fitting surface 104C of auxiliary wheel 100C, and positioning convex portion 112 is formed at the fitting surface 94C that transmits with wheel 90C.

Such as Figure 28～shown in Figure 31, transmit with wheel 90C and have from fitting surface 94C along rotation centerline CL at least 1 of auxiliary wheel 100C extension, preferred a plurality of (the embodiment 4 being 3) claw section 121.Auxiliary wheel 100C have for lock one or more claw sections 121, at least 1, preferred a plurality of (embodiment 4 is 3) hooking part 131.Claw section 121 is formations identical with the embodiment's 1 of Fig. 5～shown in Figure 11 positioning part claw section 121.Hooking part 131 is formations identical with the embodiment's 1 of Fig. 5～shown in Figure 11 hooking part 131.Be limited to each hooking part 131 by each claw section 121, thereby auxiliary wheel 100C is installed in transmission with taking turns 90C.

The wheel body 101c of auxiliary wheel 100C is the formed article that is formed with the resin of a plurality of tooth 103C at outer peripheral portion, and force application part 101b is come in by integratedly assembling by inserting moulding.The number of teeth of this tooth 103C is identical with the number of teeth of transmitting with the tooth 93 of taking turns 90C.

Such auxiliary wheel 100C be make a plurality of tooth 103C towards transmit extend with wheel 90C side, what is called is crown (is also referred to as the cap shape.) gear.A plurality of tooth 103C extend in parallel with respect to rotation centerline CL.That is, be crown auxiliary wheel 100C and pass through to surround the mode of transmitting with the outer circumferential face of wheel 90C with tooth 103C, overlap with wheel 90C with transmission, be engaged in thus worm screw 81.

On the other hand, such as Figure 27 and shown in Figure 28, force application part 101b pushes transmit auxiliary wheel 100C to wheel 90C side.In other words, force application part 101b is a kind of constituting a plurality of tooth 103C of wheel body 101c along the direction of the rotation centerline CL of auxiliary wheel 100C and from the parts of the tooth top side direction tooth bottom side application of force of worm screw 81.Therefore, auxiliary wheel 100C is not having under the state of backlash with respect to worm screw 81 engagements.

Such as Figure 28 and shown in Figure 29, the force application part 101b of auxiliary wheel 100C is the one-body molded product that are made of the discoideus inner circular part 108C of the hollow discoideus 107C of cylindrical section, hollow and flat a plurality of elastic arm 109C, wherein the 107C of cylindrical section is assembled into wheel body 101c, the diameter of inner circular part 108C is less than the internal diameter of the 107C of this cylindrical section, and be installed on and transmit with wheel 90C, a plurality of elastic arm 109C are radiated entends and link to each other with inner circular part 108C from this inner circular part 108C to the 107C of cylindrical section.This force application part 101b is the integrally formed product that are made of metal plates such as spring steel steel, for example is the punch process product.

The thickness of slab of the 107C of cylindrical section, inner circular part 108C and elastic arm 109C is identical.The center of the 107C of cylindrical section and inner circular part 108C and auxiliary wheel 100C is namely transmitted with the rotating center CL of wheel 90C identical.The position of the 107C of cylindrical section is for the position of inner circular part 108C, along at a certain distance Hc (with reference to Figure 28) biasing of rotation centerline CL of auxiliary wheel 100C.This certain distance Hc is called Offset Hc.The 107C of cylindrical section is with respect to inner circular part 108C almost parallel.

This force application part 101b that consists of like this is the roughly elastic member of " disc spring " shape of a kind of what is called that tilts, is the frustoconical shape towards middle body from wheel body 101c.The conical end is the inner circular part 108C that the tabular surface by level consists of.Roughly the force application part 101b of disc spring shape is configured to towards the face 94C step-down that transmits with the side of the wheel body 92C that takes turns 90C.Because be the force application part 101b of disc spring shape, so Offset Hc is larger, the power of the application of force becomes larger.Therefore, by Offset Hc suitably is set, the active force that at the bottom of the tooth of worm screw 81 the tooth 103C of wheel body 101c is carried out the application of force can be set as best value.

As shown in figure 27, under the state of assembling worm and gear vice mechanism 44C, by certain active force of a plurality of elastic arm 109C, the tooth 103C of at least one of auxiliary wheel 100C is pushed at the bottom of the tooth of tooth 81 of worm screw 80, namely is pushed to arrow Sp direction.Therefore, the backlash between the tooth 81 of worm screw 80 and the tooth 103C of auxiliary wheel 100C is zero, tooth 81,103C surface of contact is each other applied certain contact press so-called precompressed (being also referred to as " preload ").When worm screw 80 is in halted state, has slightly backlash at the tooth 81 of worm screw 80 with between transmitting with the tooth 93 of taking turns 90C.

Afterwards, worm screw 80 during to the forward direction rotation, press first auxiliary wheel 100C tooth 103C the flank of tooth and to make auxiliary wheel 100C rotation.At this moment, on the tooth 103C of auxiliary wheel 100C, corresponding to the pressure angle of oneself, effect has the component towards the direction (opposite direction of arrow Sp) of leaving at the bottom of the tooth of the tooth 81 of worm screw 80.Therefore, the tooth 103C of auxiliary wheel 100C overcomes the active force of a plurality of elastic arm 109C, towards the direction displacement of leaving at the bottom of the tooth of the tooth 81 of worm screw 80.The result of the tooth 103C displacement of auxiliary wheel 100C is to produce backlash between tooth 81,103C.Consequently, the tooth 81 of worm screw 80 is contacted with the tooth 93 that transmits with wheel 90C, makes to transmit with wheel 90C to begin to rotate to positive veer.

So, the tooth 81 of worm screw 80 is touched lentamente in the tooth 93 that transmits with wheel 90C.Therefore, can further improve the durability of worm and gear vice mechanism 44C.And, owing to can remove the tooth 81 of worm screw 80 and transmitting the backlash of using between the tooth 93 of taking turns 90C, therefore can further suppress the generation of

tooth

81,93 sound of cramping each other.

According to embodiment 4, play effect, the effect same with effect, the effect of above-described embodiment 1.And then, according to embodiment 4, by the backlash between the tooth 103C of the tooth 81 of worm screw 80 and auxiliary wheel 100C being set for less than the tooth 81 of worm screw 80 and being transmitted with the backlash between the tooth 93 of wheel 90C, transmitting with wheel 90C coincidence auxiliary wheel 100C, and pass through force application part 101b so simple formation of the tooth 103C application of force to auxiliary wheel 100C at the bottom of the tooth of the tooth 81 of worm screw 80, thereby can improve the durability of worm and gear vice mechanism 44C.

Need to prove, in the present invention, worm and

gear vice mechanism

44,44A～44C are not limited to oblique axis worm and gear vice mechanism, and worm screw 80 can be 90 ° with the shaft angle that transmits with

wheel

90,90A, 90C.

Industrial applicibility

Worm and gear vice mechanism 44 of the present invention, 44A～44C are suitable for: detect the steering torque that steering wheel 21 produces by steering torque sensor 41, electric motor 43 produces assist torque corresponding to the testing signal of this steering torque sensor 41, this assist torque is passed to the moving power steering gear 10 of used for automobile, the 10A～10C of steering system 20 through worm and

gear vice mechanism

44,44A～44C.

Symbol description

10,10A～10C ... driven steering device

20 ... steering system

21 ... steering wheel

29 ... the steering wheel

43 ... electric motor

44,44A～44C ... the worm and gear vice mechanism

80 ... worm screw

81 ... tooth

90,90A, 90C ... the transmission of torque worm gear

93 ... tooth

94,94C ... fitting surface

100,100A, 100C ... auxiliary worm wheel

103,103C ... tooth

104,104C ... fitting surface

105,105C ... non-fitting surface

110,110A ... the positioning part

111,111A ... the location receiving portion

112,112A ... positioning convex portion

113,113A ... elongated slot

121,121A, 121B ... claw section

122 ... arm

123 ... claw

131,131A, 131B ... hooking part

132 ... through hole

133,133A ... form the circular-arc edge of through hole

134 ... the plane of inclination

134a ... the inclination initial point

134b ... the inclination terminal point

135 ... the 1st through hole

136 ... the 2nd through hole

CL ... the transmission of torque rotation centerline (rotation centerline of auxiliary worm wheel) of worm gear

WL ... the rotation centerline of worm screw.

Claims (according to the modification of the 19th of treaty)

1. (revise afterwards) a kind of worm and gear vice mechanism, it comprise worm screw, with the transmission of torque of this worm meshing with worm gear and the auxiliary worm wheel that arranges with worm gear in this transmission of torque, by this auxiliary worm wheel the tooth of described worm screw and described transmission of torque are reduced with the backlash between a plurality of teeth of worm gear, it is characterized in that

Described auxiliary worm wheel is positioned at the position concentric with the rotation centerline of described transmission of torque usefulness worm gear, and is coincided with described transmission of torque worm gear, and can and install by the location, positioning part,

This positioning part comprises:

The location receiving portion that forms with the either party of worm gear in described auxiliary worm wheel and described transmission of torque and

Be formed at described auxiliary worm wheel and described transmission of torque and use the opposing party that appoints of worm gear, can embed the positioning convex portion of described location receiving portion,

Described location receiving portion is formed at the fitting surface of described auxiliary worm wheel and the either party that described transmission of torque is used the fitting surface of worm gear,

Described positioning convex portion is formed at the opposing party of described fitting surface and the described fitting surface that described transmission of torque is used worm gear of described auxiliary worm wheel,

One side's at receiving portion place, described location described fitting surface also has the circular-arc elongated slot take described rotation centerline as benchmark,

Described location receiving portion is made of the recess of a part that is positioned at the bottom land that forms described elongated slot,

Described positioning convex portion can be by embedding described elongated slot be guided by this elongated slot and is indexed to described location receiving portion.

2. (deletion)

3. (revise afterwards) worm and gear vice mechanism as claimed in claim 1, wherein,

The described transmission of torque that is formed among described location receiving portion and the described positioning convex portion becomes one with a side of worm gear and this transmission of torque a plurality of profiles of tooth with worm gear.

4. (deletion)

5. (revise afterwards) worm and gear vice mechanism as claimed in claim 1, wherein,

Described transmission of torque has towards the opposing party along the claw section that described rotation centerline extends with the either party of worm gear and described auxiliary worm wheel, and described the opposing party has the hooking part that can lock described claw section,

Be limited to described hooking part by described claw section and limit to the displacement along the direction of described rotation centerline, described auxiliary worm wheel is installed in described transmission of torque worm gear thus.

6. worm and gear vice mechanism as claimed in claim 5, wherein,

Described claw section comprises:

The arm that extends along the described auxiliary worm wheel of described rotating center alignment with the described fitting surface of worm gear from described transmission of torque and

Use the outstanding claw of described fitting surface of worm gear along described transmission of torque from the front end of this arm,

Described hooking part comprises:

Connect described auxiliary worm wheel along described rotation centerline, and form take described rotation centerline as benchmark circular-arc through hole and

Along the circular-arc edge that forms this through hole, be formed at the plane of inclination of the non-fitting surface of described auxiliary worm wheel,

Described through hole comprises:

Can for described arm and described claw insert simultaneously the 1st logical through hole and

The 2nd through hole that links to each other and only can supply described arm to connect with the 1st through hole,

Described plane of inclination has the inclination initial point at the depth location of the described non-fitting surface of the described auxiliary worm wheel of distance and the border of described the 1st through hole and described the 2nd through hole, and tilt to extend to described non-fitting surface from this inclination initial point along described the 2nd through hole, with the beveled end of this extension as the inclination terminal point

Described claw insert with described arm lead in described the 1st through hole after, by with respect to described auxiliary worm wheel take described rotation centerline as benchmark relatively rotates described claw, when described claw is positioned at described non-fitting surface being guided by described plane of inclination, can has and flexibly be limited to this non-fitting surface.

7. worm and gear vice mechanism as claimed in claim 6, wherein,

Described location receiving portion is when described claw is limited to the described non-fitting surface of described auxiliary worm wheel, and being positioned at can be on the chimeric position of described positioning convex portion.

8. such as claim 6 or 7 described worm and gear vice mechanisms, wherein,

Described transmission of torque is the integral piece that mutually is shaped and is integrated by resin material with worm gear, described positioning convex portion, described arm and described claw,

Described claw is outstanding towards described rotation centerline from described arm.

9. worm and gear vice mechanism as claimed in claim 1, wherein,

By forming towards the opposing party along the claw section that described rotation centerline extends with the either party of worm gear and described auxiliary worm wheel in described transmission of torque, form the hooking part that can embed and can lock described claw section described the opposing party, thus

Described positioning convex portion is made of described claw section, and described location receiving portion is made of described hooking part,

Embed and be limited to described hooking part by described claw section, restriction is towards the displacement along the direction of described rotation centerline, and described auxiliary worm wheel is positioned and is installed on described transmission of torque worm gear thus.

10. (revise rear) such as each described worm and gear vice mechanism in the claim 1,3,5 to 9, wherein,

Described auxiliary worm wheel has a plurality of teeth that mesh for the described tooth with described worm screw,

These a plurality of teeth are by constituting the bending deflection that can have to the sense of rotation of described auxiliary worm wheel spring performance, under the state of the sense of rotation bending of described auxiliary worm wheel, joining with described worm screw, can make thus described worm screw and described transmission of torque with at least one party's rotation of worm gear.

11. worm and gear vice mechanism as claimed in claim 10, wherein,

When described transmission of torque was not all joined with respect to the described tooth of described worm screw with described a plurality of teeth of worm gear, at least one of described a plurality of teeth of described auxiliary worm wheel joined with the described tooth of described worm screw under the state of the sense of rotation bending of described auxiliary worm wheel.

12. worm and gear vice mechanism as claimed in claim 10, wherein,

At least one of described a plurality of teeth of described auxiliary worm wheel joined with the described tooth of described worm screw under the state of the sense of rotation bending of described auxiliary worm wheel all the time.

13. worm and gear vice mechanism as claimed in claim 10, wherein,

When the sense of rotation of described worm screw is switched to reverse direction from positive veer, among described transmission of torque is used a plurality of described tooth of worm gear, before being about to switch to described reverse direction from from the 1st tooth of the described tooth engagement of described worm screw to be engaged in 2nd tooth different with the 1st tooth during, at least one of described a plurality of teeth of described auxiliary worm wheel joined with the described tooth of described worm screw under the state of the sense of rotation bending of described auxiliary worm wheel.

14. such as each described worm and gear vice mechanism in the claim 10 to 13, wherein,

Described auxiliary worm wheel is the formed article that comprises that described a plurality of tooth integral body is integrated by ester moulding.

(15. after revising) a kind of driven steering device that uses the worm and gear vice mechanism, it possesses:

Each described worm and gear vice mechanism in the claim 1,3,5 to 14;

Steering system from the steering wheel of vehicle to the steering wheel; And

Produce torque and this torque is passed to the electric motor of described steering system through described worm and gear vice mechanism.

Claims

1. worm and gear vice mechanism, it comprise worm screw, with the transmission of torque of this worm meshing with worm gear and the auxiliary worm wheel that arranges with worm gear in this transmission of torque, by this auxiliary worm wheel the tooth of described worm screw and described transmission of torque are reduced with the backlash between a plurality of teeth of worm gear, it is characterized in that

This positioning part comprises:

Be formed at described auxiliary worm wheel and described transmission of torque and use the opposing party that appoints of worm gear, can embed the positioning convex portion of described location receiving portion.

2. worm and gear vice mechanism as claimed in claim 1, wherein,

Described positioning convex portion is formed at the opposing party of described fitting surface and the described fitting surface that described transmission of torque is used worm gear of described auxiliary worm wheel.

3. worm and gear vice mechanism as claimed in claim 2, wherein,

4. worm and gear vice mechanism as claimed in claim 2 or claim 3, wherein,

5. such as each described worm and gear vice mechanism in the claim 1 to 4, wherein,

6. worm and gear vice mechanism as claimed in claim 5, wherein,

Described claw section comprises:

Described hooking part comprises:

Described through hole comprises:

7. worm and gear vice mechanism as claimed in claim 6, wherein,

8. such as claim 6 or 7 described worm and gear vice mechanisms, wherein,

9. worm and gear vice mechanism as claimed in claim 1, wherein,

10. such as each described worm and gear vice mechanism in the claim 1 to 9, wherein,

11. worm and gear vice mechanism as claimed in claim 10, wherein,

12. worm and gear vice mechanism as claimed in claim 10, wherein,

13. worm and gear vice mechanism as claimed in claim 10, wherein,

15. a driven steering device that uses the worm and gear vice mechanism, it possesses:

Each described worm and gear vice mechanism in the claim 1 to 14;

Steering system from the steering wheel of vehicle to the steering wheel; And