JP2017165329A - Steering gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a steering gear which does not need a new space for receiving a load generated by a speed reducer.SOLUTION: A steering gear (1) includes: a motor (13); a middle steering shaft (102) which is connected to a steering member, which is steered by an operator, so as to transmit torque thereto; a second shaft (122) disposed at an outer periphery of the middle steering shaft (102) and to which torque is applied by the motor (13); a first speed reducer (15) which transmits the torque of the second shaft (122) to the middle steering shaft (102); a housing (11) which houses the second shaft (122) and the first speed reducer (15); a support radial bearing (42) supporting the second shaft (12); and a bolt (65) which fixes the support radial bearing (42) to the housing (11).SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steering apparatus.

  In a steering device that employs an electric power steering system or a steer-by-wire system, a vehicle steering device that uses a reduction mechanism for transmitting the output of a motor to a steering shaft is known (Patent Document 1).

Japanese Patent Laid-Open No. 2007-11297

  In a steering device using a speed reduction mechanism, a load may be generated in the axial direction of the steering device by the speed reduction mechanism. Therefore, a structure for receiving the load is necessary.

  By the way, it is preferable that the steering device using the speed reduction mechanism as described above is small.

  An object of the present invention is to realize a steering device that can be reduced in size in a steering device that uses a speed reduction mechanism.

  For this purpose, the present invention provides a motor, a first shaft connected to a steering member for steering operation by a driver so as to transmit torque, and an outer periphery of the first shaft. A second shaft to which the torque is applied, a transmission portion that transmits torque of the second shaft to the first shaft, a housing that houses the second shaft and the transmission portion, and a radial bearing that supports the second shaft And a fixing member that fixes the radial bearing to the housing.

  According to the present invention, the steering device can be reduced in size.

It is a schematic diagram which shows typically an example of the principal part structure of the steering device which concerns on Embodiment 1 of this invention. It is sectional drawing which shows typically an example of the internal structure of the housing shown in FIG. FIG. 3 is an enlarged view of the periphery of the supporting radial bearing shown in FIG. 2. It is sectional drawing which shows typically an example of the internal structure of the housing which concerns on Embodiment 2 of this invention. It is an enlarged view of the periphery of the radial bearing for support shown in FIG. It is sectional drawing which shows typically the structure of the periphery of the radial bearing for support based on Embodiment 3 of this invention fixed with the volt | bolt.

Embodiment 1
A steering apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram schematically illustrating an example of a main part configuration of a steering apparatus according to an embodiment of the present invention. As shown in FIG. 1, the steering device 1 includes a steering unit 10 that receives a steering operation by a driver, a steering unit 20 that steers a wheel 400 according to the steering operation that the steering unit 10 receives, and a control unit (non-control unit). (Shown). In the steering device 1 described below, an electric power steering system (hereinafter referred to as EPS) that uses a motor (not shown in FIG. 1) to exert an assist force is employed, but this limits the present embodiment. (1) It is possible to mechanically connect or cut off the torque transmission path between the steering unit 10 and the steered unit 20, and (2) In the state where the torque transmission path is cut off, A steer-by-wire system that electrically controls the turning angle of the wheel 400 according to the steering operation received by the steering unit 10 may be employed.

(Steering part 10)
As shown in FIG. 1, the steering unit 10 includes a steering member 50, an upper steering shaft 101, a middle steering shaft (first shaft) 102, a housing 11, a lower steering shaft 103, a first universal joint 106, and an intermediate shaft 108. It has. The steering member 50, the upper steering shaft 101, the middle steering shaft 102, and the lower steering shaft 103 are connected to each other so as to be able to transmit torque.

  The upper steering shaft 101 and the middle steering shaft 102 may be formed integrally or may be connected to each other via a torsion bar or the like. In the present specification, the upper steering shaft and the middle steering shaft may be collectively referred to as a middle steering shaft.

  Further, in this specification, “connection so that torque transmission is possible” means that the other member is connected to rotate with the rotation of one member. For example, one member and the other member are connected. Including the case where the one member and the other member are indirectly connected via a third member (for example, a joint member) (hereinafter the same).

  In the present embodiment, the upper end of the upper steering shaft 101 is fixed to the steering member 50 and rotates integrally with the steering member 50. Further, the lower end of the lower steering shaft 103 and the upper end of the intermediate shaft 108 are connected to each other via the first universal joint 106.

  In the present specification, the “upper end” refers to an upstream end portion (that is, an input end portion) in a steering force transmission path according to the steering operation of the driver, and the “lower end” refers to In the steering force transmission path, the downstream end portion (that is, the output end portion) is indicated (the same applies hereinafter).

  In the following description, “upstream side” and “downstream side” refer to the upstream side and the downstream side in the transmission path of the steering force.

  Further, as an example of the steering member 50, an annular steering wheel is given as an example as shown in FIG. 1, but this is not a limitation of the present embodiment, and a steering operation by the driver can be accepted. Any other shape or mechanism may be used.

(Steering part 20)
The steered portion 20 is configured to steer the wheels 400 according to the driver's steering operation received by the steering portion 10.

  As shown in FIG. 1, the steered portion 20 includes a second universal joint 202, a pinion shaft 204, a pinion gear 206, a rack bar (steering shaft) 208, a tie rod 210, and a knuckle arm 212. The intermediate shaft 108, the pinion shaft 204, and the pinion gear 206 are connected to each other so as to be able to transmit torque.

  In the present embodiment, the pinion gear 206 is fixed to the lower end of the pinion shaft 204 and rotates integrally with the pinion shaft 204. Further, the lower end of the intermediate shaft 108 and the upper end of the pinion shaft 204 are connected to each other via the second universal joint 202.

  The rack bar 208 is configured to steer the wheel 400 according to the rotation of the pinion gear 206. Rack teeth (not shown) that mesh with the pinion gear 206 are formed on the rack bar 208.

  In the steering apparatus 1 configured as described above, when the driver performs a steering operation via the steering member 50, the pinion gear 206 rotates and the rack bar 208 is displaced along the axial direction of the rack bar 208. As a result, the wheel 400 is steered via the tie rods 210 provided at both ends of the rack bar 208 and the knuckle arms 212 connected to the tie rods 210.

  In the example shown in FIG. 1, the configuration in which the steering force is transmitted between the pinion shaft 204 and the rack bar 208 by the pinion gear 206 and the rack teeth is taken as an example, but this configuration limits the present embodiment. Instead, any other configuration may be used as long as it can transmit the steering force between the pinion shaft 204 and the rack bar 208.

  Next, the internal configuration of the housing 11 described above will be described with reference to FIG.

(Internal structure of housing 11)
FIG. 2 is a cross-sectional view schematically showing an example of the internal configuration of the housing 11 shown in FIG.

  As shown in FIG. 2, a part of the middle steering shaft (first shaft) 102 is accommodated in the housing 11. The housing 11 includes a first housing 151 and a second housing 152. A first speed reducer (transmission unit) 15 is accommodated on the first housing 151 side. On the other hand, the second reduction gear 16 is accommodated on the second housing 152 side. An end cover 153 is attached to the downstream side of the second housing 152. Further, a motor 13 is provided outside the housing 11. Hereinafter, the internal configuration on the first housing 151 side and the internal configuration on the second housing 152 side will be described in detail.

(Internal configuration on the first housing 151 side)
On the first housing 151 side, a part of the middle steering shaft 102, a part of the second shaft 122, the first radial bearing 41, and the first speed reducer 15 are accommodated.

  The middle steering shaft 102 is connected to the steering member 50 (see FIG. 1) that is steered by the driver so that torque can be transmitted. The first speed reducer 15 is configured to transmit torque to the middle steering shaft 102 after decelerating the rotation of the second shaft 122. The second shaft 122 is a cylindrical member, and the middle steering shaft 102 passes through the second shaft 122. That is, the second shaft 122 is disposed on the outer periphery of the middle steering shaft 102.

  The first speed reducer 15 includes a sun roller (tubular member) 71, a plurality of planetary rollers (planetary members) 73, a first ring member 74, a second ring member 75, and a carrier 77.

  The sun roller 71 is disposed on the outer periphery of the second shaft 122. In the present embodiment, the sun roller 71 is tightly fitted by being press-fitted into the second shaft 122. However, this does not limit the present embodiment. It may be fixed to the two shafts 122.

  The plurality of planetary rollers 73 are disposed on the outer periphery of the sun roller 71 and are in pressure contact with the outer peripheral surface of the sun roller 71.

  The carrier 77 is disposed on the outer periphery of the middle steering shaft 102. The carrier 77 rotatably supports each of the plurality of planetary rollers 73 via a shaft (not shown) connected to the carrier 77. In the present embodiment, the carrier 77 is tightly fitted by being press-fitted into the middle steering shaft 102. However, this is not a limitation of the present embodiment, and the carrier 77 is formed by other methods. 102 may be fixed. With such a configuration, each planetary roller 73 can perform two types of movements: rotation about the axis connected to the carrier 77 (rotation) and movement along the outer periphery of the sun roller 71 (revolution). Yes.

  A first ring member 74 and a second ring member 75 are provided on the outer side of the planetary roller 73 in the upstream and downstream directions with respect to the planetary roller 73. The first ring member 74 and the second ring member 75 are fixed to the first housing 151, respectively. The first ring member 74 is in contact with the planetary roller 73 from the upstream side. The second ring member 75 is in contact with the planetary roller 73 from the downstream side. The contact between the first ring member 74 or the second ring member and the planetary roller 73 is preferably point contact, but may be line contact or surface contact.

  As each of the first ring member 74 and the second ring member 75 comes into contact with the planetary roller 73, the planetary roller 73 is pressed against the sun roller 71 side. In the above example, the power is transmitted by the friction generated between the sun roller 71 and each planetary roller 73. Here, in this specification, “transmitting power by friction” means transmitting power by a friction drive system or a traction drive system. The “friction drive system” is a method of transmitting power from the driving roller to the driven roller by the frictional force between the two rollers in pressure contact and in direct contact. The “traction drive system” is a method of transmitting power by a frictional force through a lubricating oil film interposed between two pressure-contacted rollers.

  However, the present embodiment is not limited to the above example, and instead of the sun roller 71, the plurality of planetary rollers 73, the first ring member 74, and the second ring member 75, the first deceleration The machine 15 may include a sun gear, a plurality of planetary gears that mesh with the sun gear, and an internal gear that meshes with the planetary gear.

  The first radial bearing 41 is disposed on the outer periphery of the middle steering shaft 102 on the upstream side of the first housing 151. The first radial bearing 41 includes an inner ring 411, an outer ring 412, and a plurality of rolling elements 413 disposed between the inner ring 411 and the outer ring 412. In the present embodiment, the rolling element refers to, for example, a ball, a roller, or the like (the same applies hereinafter). In the present embodiment, the first radial bearing 41 is tightly fitted by press-fitting the inner ring 411 into the middle steering shaft 102. On the other hand, the outer ring 412 is in contact with the convex portion 170 formed in the first housing 151 from the downstream side. However, this configuration does not limit the present embodiment, and the first radial bearing 41 may be fixed to the middle steering shaft 102 by other methods.

  Next, the internal configuration on the second housing 152 side will be further described with reference to FIG.

(Internal structure on the second housing 152 side)
As shown in FIG. 2, on the second housing 152 side, a part of the middle steering shaft 102, a part of the second shaft 122, a supporting radial bearing (radial bearing) 42, a power transmission shaft, and a second shaft A reduction gear 16 is accommodated. FIG. 3 is an enlarged view of the periphery of the supporting radial bearing 42 shown in FIG.

  The supporting radial bearing 42 is a radial bearing that supports the second shaft 122. In the present embodiment, the supporting radial bearing 42 is disposed on the outer periphery of the second shaft 122. The supporting radial bearing 42 includes an inner ring 421, an outer ring 422, and a plurality of rolling elements 423 disposed between the inner ring 421 and the outer ring 422. Further, the outer ring 422 is formed with a flange portion 424 by partially expanding the outer ring 422 toward the outer peripheral side. A through hole 174 (fixing through hole) through which the bolt 65 (fixing member) passes is formed in the flange portion 424. The flange portion 424 is configured to abut against the concave portion 155 formed in the second housing 152 from the downstream side. The supporting radial bearing 42 is fixed to the second housing 152 by a bolt 65 inserted into the through hole 174 of the flange 424 in a state where the flange 424 is fitted in the recess 155.

  The second reduction gear 16 is disposed on the outer periphery of the middle steering shaft 102. In the present embodiment, the second speed reducer 16 is configured as a belt speed reducer including a belt 81, a drive pulley 85, and a driven pulley 86. The drive pulley 85 is fixed to the power transmission shaft 14 that is rotationally driven by the motor 13, and rotates integrally with the power transmission shaft 14. Torque generated by the motor 13 is transmitted to the second shaft 122 via the power transmission shaft 14, the belt 81 and the driven pulley 86. However, the second reduction gear 16 according to the present embodiment is not limited to this. Therefore, the second reduction gear 16 may be configured as a worm gear mechanism using a worm wheel, for example, and the torque generated by the motor 13 may be transmitted to the second shaft 122 via the worm gear and the worm wheel. .

  In the present embodiment, a lightening portion 87 is formed in the driven pulley 86 by performing a lightening process on the inside of the driven pulley 86. The lightening portion 87 is formed so that the bolt 65 does not contact the driven pulley 86.

  Further, a bolt through hole 69 through which a tool 67 (indicated by a virtual line in the drawing) for fastening the bolt 65 passes is formed in the lightening portion 87. In this embodiment, as will be described in detail later, the tool 67 is used only for fastening the bolt 65, and the tool 67 does not remain inside the housing 152 after fastening.

  In the present embodiment, since the second speed reducer 16 is a belt speed reducer, the driven pulley 86 is formed with a lightening portion 87, but the present invention is not limited to this. For example, the second speed reducer When 16 is a worm gear mechanism, the worm wheel may have a lightening portion.

  The driven pulley 86 is tightly fitted by being press-fitted into the second shaft 122, but this does not limit the present embodiment, and the driven pulley 86 is fixed to the second shaft 122 by other methods. May be.

  An end cover 153 is attached to the downstream side of the second housing 152. A second radial bearing 43 is provided on the downstream side of the end cover 153. The second radial bearing 43 includes an inner ring 431, an outer ring 432, and a plurality of rolling elements 434 arranged between the inner ring 431 and the outer ring 432. In the present embodiment, the second radial bearing 43 is tightly fitted by the outer ring 432 being press-fitted inside the end cover 153. Further, the outer ring 432 of the second radial bearing 43 is in contact with the convex portion 156 formed on the end cover 153 from the upstream side. However, this configuration does not limit the present embodiment, and the second radial bearing 43 may be fixed by other methods.

  According to the above configuration, the load generated by the second reduction gear 16 can be received by the supporting radial bearing 42 fixed to the second housing 152. Therefore, according to this embodiment, the load generated by the second reduction gear 16 can be received without requiring a new space. Therefore, by shortening the total length of the housing 11 in the axial direction, the steering apparatus 1 (see FIG. 1) as a whole can be reduced in size.

  Moreover, according to this embodiment, since the 2nd reduction gear 16 is arrange | positioned between the radial bearing 42 for support, and the 2nd radial bearing 43, the movement of the axial direction of the 2nd reduction gear 16 is carried out. That is, the movement of the second reduction gear 16 to the upstream side and the downstream side can be restricted.

[Embodiment 2]
The housing with which the steering apparatus in this embodiment is provided is demonstrated with reference to FIG.4 and FIG.5. Note that members already described in this specification are denoted by the same reference numerals, and description thereof will be omitted below.

  FIG. 4 is a cross-sectional view schematically showing an example of the internal configuration of the housing according to the present embodiment. FIG. 5 is an enlarged view of the periphery of the supporting radial bearing shown in FIG. The housing 31 according to the present embodiment is configured to include the housing 31 instead of the configuration of the housing 11 (see FIG. 2) according to the first embodiment described above. Below, the housing 31 which concerns on this embodiment is demonstrated centering on a different point from the housing 11 which concerns on Embodiment 1. FIG.

  The housing 31 according to the present embodiment includes a first housing 171 and a second housing 172. In the present embodiment, unlike the first embodiment, the first housing 171 is configured to accommodate only a part of the middle steering shaft 132. Since the middle steering shaft 132 is different in shape from the middle steering shaft 102 (see FIG. 2) according to the first embodiment, the middle steering shaft 132 is numbered differently. However, the basic function of the middle steering shaft 132 is the same as that of the middle steering shaft 102.

  The second housing 172 houses a part of the middle steering shaft 132, the second shaft 122, the first radial bearing 51, the supporting radial bearing 42, the first reduction gear 25, and the second reduction gear 16. Has been.

  The first speed reducer 25 includes a sun roller (tubular member) 71, a plurality of planetary rollers (planetary members) 73, a first ring member 74, a second ring member 75, and a carrier 88.

  The first speed reducer 25 is common to the first speed reducer 15 except that the shape of the carrier 88 is different from the carrier 77 (see FIG. 2) of the first speed reducer 15 according to the first embodiment. Therefore, hereinafter, the first speed reducer 25 will be described focusing on differences from the first speed reducer 15.

  In the present embodiment, as shown in FIG. 4, a convex portion 89 is formed on the carrier 88. A convex portion 173 is formed on the first housing 171 side. In the present embodiment, the first radial bearing 51 is tightly fitted by press-fitting the inner ring 511 into the carrier 88. The inner ring 511 of the first radial bearing 51 is in contact with the convex portion 89 of the carrier 88 from the upstream side. Further, the outer ring 512 of the first radial bearing 51 is in contact with the convex portion 173 of the first housing 171 from the downstream side. However, these configurations do not limit the present embodiment, and the first radial bearing 51 may be fixed to the carrier 88 by other methods.

  Further, in the present embodiment, the flange portion 424 of the supporting radial bearing 42 is configured to fit into a recess 179 formed in the first housing 172. Further, the supporting radial bearing 42 is attached to the second housing 172 by the bolt 65 inserted into the through hole 178 (fixing through hole) of the flange portion 424 in a state where the flange portion 424 is fitted in the recess 179. Is fixed.

  Further, in the present embodiment, an end cover 163 is attached to the downstream side of the second housing 172. A convex portion 156 is formed on the end cover 163. Further, a convex portion 182 is formed on the downstream side of the middle steering shaft 132. In addition, the second radial bearing 53 includes an inner ring 531, an outer ring 532, and a plurality of rolling elements 533 disposed between the inner ring 531 and the outer ring 532. In the present embodiment, the second radial bearing 53 is tightly fitted by press-fitting the outer ring 532 inside the end cover 163. Further, the inner ring 531 of the second radial bearing 53 is in contact with the convex portion 182 of the middle steering shaft 132 from the downstream side. Further, the outer ring 532 of the second radial bearing 53 is in contact with the convex portion 156 of the end cover 163 from the upstream side. However, these configurations do not limit the present embodiment, and the second radial bearing 53 may be fixed by other methods.

  Thus, by providing the convex portion 182 on the side of the middle steering shaft 132, the diameter of the fitting portion of the middle steering shaft 132 and the end cover 163 with respect to the second radial bearing 53 can be reduced.

  According to the present embodiment, both the first radial bearing 41 and the supporting radial bearing 42 are fixed to the second housing 172. Therefore, misalignment in the axial direction can be reduced.

[Embodiment 3]
A method of fixing the supporting radial bearing to the housing in the steering apparatus according to the present embodiment will be described with reference to FIG.

  In the present embodiment, instead of the supporting radial bearing fixing method according to the first and second embodiments, a configuration in which the supporting radial bearing is fixed using a head portion of a bolt will be described with reference to FIG. In the following description, a different part from the said embodiment is demonstrated and description is abbreviate | omitted about the part similar to the said embodiment.

  FIG. 6 is a cross-sectional view schematically showing a configuration around a supporting radial bearing fixed with bolts. FIG. 6A is a first configuration example, and FIG. 6B is a second configuration example. Correspond.

(First configuration example)
In the first configuration example, as shown in FIG. 6A, the supporting radial bearing 76 is disposed on the outer periphery of the second shaft (not shown). The supporting radial bearing 76 includes an inner ring 761, an outer ring 762, and a plurality of rolling elements 763 arranged between the inner ring 761 and the outer ring 762. The supporting radial bearing 76 has a configuration without a flange as shown in FIG.

  On the housing 283 side to which the supporting radial bearing 76 is fixed, a convex portion 285 is formed on which the outer ring 762 of the supporting radial bearing 76 can abut from the downstream side. The housing 283 according to this embodiment is the same as the housing 152 (see FIG. 2) or the housing 172 (see FIG. 4) in each of the above-described embodiments.

  In the first configuration example, the outer ring 762 is pressed against the convex portion 285 from the downstream side by the head portion 75 of the bolt 65, whereby the supporting radial bearing 76 is fixed to the housing 283. As described above, in the configuration in which the supporting radial bearing 76 does not have the flange portion, the head portion 75 of the bolt 65 may be used for fixing.

  Even with the above configuration, the load generated by the second reduction gear can be received without requiring a new space. The overall size of the steering apparatus according to this embodiment can be reduced.

(Second configuration example)
In the second configuration example, as shown in FIG. 6B, the supporting radial bearing 96 is disposed on the outer periphery of the second shaft (not shown). The supporting radial bearing 96 includes an inner ring 961, an outer ring 962, and a plurality of rolling elements 963 disposed between the inner ring 961 and the outer ring 962. In addition, the outer ring 962 is formed with a flange portion 964 that extends in a planar shape toward the outer peripheral side of the supporting radial bearing 96. However, the through-hole through which the bolt passes is not formed in the flange portion 964.

  On the side of the housing 287 to which the supporting radial bearing 96 is fixed, a recess 289 is formed in which the flange 964 of the supporting radial bearing 96 can come into contact from the downstream side. The housing 287 according to this embodiment is the same as the housing 152 (see FIG. 2) or the housing 172 (see FIG. 4) in each of the above-described embodiments.

  In the second configuration example, the support radial bearing 96 is fixed to the housing 287 by pressing the flange portion 964 against the concave portion 289 from the downstream side by the head portion 75 of the bolt 65. As described above, in the configuration in which the flange portion 964 of the support radial bearing 96 does not have a through hole, the support radial bearing 96 may be fixed using the head portion 75 of the bolt 65.

  Even with the above configuration, the load generated by the second reduction gear can be received without requiring a new space. The overall size of the steering apparatus according to this embodiment can be reduced.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Steering device 13 ... Motor 11, 31, 283, 287 ... Housing 15 ... 1st reduction gear (transmission part)
16 ... 2nd speed reducer 42, 76, 96 ... Radial bearing for support (radial bearing)
65 ... Bolt (fixing member)
67 ・ ・ ・ Tool 69 ・ ・ ・ Bolt through hole (through hole)
87 ... Meat removal part 102 ... Middle steering shaft (first axis)
122 ・ ・ ・ Second shaft 178 ・ ・ ・ Through hole (fixing through hole)
421 ... outer ring 424, 964 ... buttocks

Claims (6)

A motor,
A first shaft connected to be able to transmit torque to a steering member that is steered by a driver;
A second shaft disposed on an outer periphery of the first shaft and applied with torque by the motor;
A transmission portion for transmitting the torque of the second shaft to the first shaft;
A housing for accommodating the second shaft and the transmission portion;
A radial bearing supporting the second shaft;
A steering apparatus comprising: a fixing member that fixes the radial bearing to the housing. A flange is formed on the outer ring of the radial bearing,
The steering device according to claim 1, wherein the fixing member fixes the radial bearing to the housing by fixing the flange portion.   The steering apparatus according to claim 2, wherein the flange portion is fitted into a recess formed in the housing. A fixing through hole is formed in the collar portion,
The steering device according to claim 2 or 3, wherein the fixing member fixes the radial bearing to the housing by penetrating the fixing through hole. A transmission member for transmitting torque from the motor to the second shaft is fixed to the outer periphery of the second shaft,
The steering apparatus according to any one of claims 1 to 4, wherein a hollow portion is formed on the transmission member so as not to contact the fixing member. The fixing member is a bolt,
The steering device according to any one of claims 1 to 5, wherein the transmission member is formed with a through hole through which a tool for fastening the bolt passes.

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