JP5472686B2 - Vehicle steering system - Google Patents

Description

  The present invention relates to a vehicle steering apparatus.

2. Description of the Related Art A vehicle steering apparatus is known that includes a transmission ratio variable mechanism that can change a transmission ratio as a ratio of an output rotation angle to an input rotation angle (see, for example, Patent Document 1).
The transmission ratio variable mechanism disclosed in Patent Document 1 is inclined with respect to the first gear that is rotationally restricted by the upper steering shaft, the fourth gear that is rotationally restricted by the lower steering shaft, and the rotation axes of the first and fourth gears. And an oscillating gear having an axis. Second and third gears are formed at both ends of the outer ring gear portion of the swing gear, the second gear meshes with the first gear, and the third gear meshes with the fourth gear.

JP 2006-82718 A

  In Patent Document 1, a bearing that supports the first gear is disposed, and a bearing that supports the fourth tooth is disposed. All of these bearings are arranged on the inner side in the radial direction with respect to the meshing portion of the first gear and the second gear and the meshing portion of the third gear and the fourth gear, and have a small diameter. . Therefore, in the space inside the radial direction of these bearings, there is little space for arranging members, and it is difficult to effectively use this space. Therefore, there is room for downsizing the device. In addition, it is preferable to maintain a highly accurate meshing state between the gears by increasing the rigidity of the support of the gear member of the transmission ratio variable mechanism.

  The present invention has been made under such a background, and provides a vehicle steering apparatus that can achieve downsizing and can maintain a highly accurate meshing state of members that mesh with each other. Objective.

In order to achieve the above object, the present invention changes the transmission ratio (θ2 / θ1) as the ratio of the turning angle (θ2) of the steered wheel side member (12) to the steering angle (θ1) of the steering member (2). In the vehicle steering apparatus (1) including the variable transmission ratio mechanism (5), the transmission ratio variable mechanism is connected to the steering member and is rotatable about the first axis (Z1) and the input member (20). , Having an output member (22) connected to the steered wheel side member and rotatable about the first axis, and first and second end faces (71, 72), and the input member and the output member can be differentially rotated. An inner ring (391) connected to the outer ring, an outer ring (392) rotatably supporting the inner ring via a rolling element (393), an actuator (23) capable of rotating the outer ring, and the input member rotatably supported The first bearing (31) and the output member are rotatable A second bearing (32) having a second axis (Z2) as a central axis of the inner ring and the outer ring is inclined with respect to the first axis, and the input member and the output member are The concave and convex engaging portions (61, 62) have power transmission surfaces (70, 73) facing the corresponding end surfaces of the inner ring, and engage each end surface of the inner ring and the power transmission surfaces corresponding to the end surfaces so as to be able to transmit power. ) Are provided, and the concave / convex engaging portion has a predetermined relationship between each end surface and the convex portion (77, 87) provided on one of the power transmission surfaces corresponding to the end surface and the convex portion provided on the other end. A recess (80, 110) that engages at a joining point (P1, P2), and at least one of the first and second bearings in the orthogonal direction (Y1) orthogonal to the first axis. The distance from the axis 1 (X1, X2) Distance from the first axis of respectively (X3, X4) as compared to long rot, connecting the said at least one of the first and second bearings provided in the corresponding input member and the output member The connecting portion is connected to a portion (202, 222), and the connecting portion has an opposing end surface (202b, 222b) facing the outer ring, and an annular receiving recess (123) for storing a part of the outer ring on the opposing end surface. , 127) is formed (claim 1).

  According to the present invention, by disposing at least one of the first bearing and the second bearing sufficiently away from the first axis, a sufficient space on the radially inner side of the at least one bearing is sufficient. Can be secured. Thereby, the space which arrange | positions components, such as an input member and an output member, can fully be ensured inside the radial direction of the said at least one bearing. Therefore, the components can be arranged so that the dead space inside the radial direction of the at least one bearing is reduced. As a result, the apparatus can be reduced in size. In addition, the thickness in the radial direction of the at least one bearing can be sufficiently secured while achieving downsizing of the apparatus. Thereby, the rigidity of the support of the corresponding input member and output member by the at least one bearing can be sufficiently secured. As a result, it is possible to more reliably maintain a high-precision meshing state between the convex portions and the concave portions formed on the power transmission surfaces of the corresponding input members and output members and the end surfaces facing the power transmission surfaces. Thereby, it can prevent that the engagement sound of a convex part and a recessed part becomes large.

In the present invention, at least one of the first and second bearings is connected to a connecting portion provided in a corresponding input member and output member, and the connecting portion is an opposed end surface facing the outer ring. the a, to the opposite end face, the housing recess of the annular housing the portion of the outer ring is formed, there are the following advantages.

That is , by accommodating a part of the outer ring in the accommodating recess, at least one of the first and second bearings and the corresponding input member and output member are arranged to overlap with each other in the axial direction of the first axis. Can do. Thereby, regarding the axial direction of the first axis, the apparatus can be made shorter and miniaturized.
Further, in the present invention, the power transmission surface of the member (20, 22) supported by the bearing is biased toward the corresponding end surface side of the inner ring via the coupling portion and the bearing coupled to the coupling portion. The urging member (141, 142) may be provided (claim 2 ).

In this case, a preload can be applied to the concave-convex engaging portion by pressing one of the convex portion and the concave portion of the concave-convex engaging portion toward the other side. Thereby, rattling can be prevented from occurring in the engagement between the convex portion and the concave portion. As a result, the engagement between the convex portion and the concave portion can be made smoother.
Further, in the present invention, the at least one of the first and second bearings and the engagement point on the corresponding input member and output member side are overlapped with respect to the axial direction (S1) of the first axis. (Claim 3 ).

In this case, at least one of the first and second bearings can reliably receive a radial load acting on the corresponding input member and output member side engagement points. As a result, the rigidity of supporting the corresponding input member and output member by at least one of the first and second bearings can be further increased.
In the present invention, with respect to the orthogonal direction, the distance from the first axis of each of the first and second bearings is from the first axis of the engagement point of each of the concave and convex engaging portions. A first plane that is longer than the distance of the first axis and is inclined with respect to the first axis through both the engagement points in a plane (F1) including the engagement points of the first axis and the concave-convex engagement portions. The first bearing is disposed between the inclined line (L1) and an orthogonal line (L3) that passes through the intersection (P3) of the first inclined line and the first axis and is orthogonal to the first axis, In the plane, the second inclined bearing may be disposed between the first inclined line and the second inclined line (L2) symmetrically arranged around the orthogonal line and the orthogonal line. (Claim 4 ).

  In this case, the thickness of the first bearing with respect to the radial direction of the first bearing can be sufficiently secured, and the first bearing is disposed close to the engagement point on the input member side with respect to the axial direction of the first axis. it can. Thereby, the apparatus can be shortened and miniaturized in the axial direction of the first axis while sufficiently increasing the rigidity of the support of the input member. In addition, the thickness of the second bearing with respect to the radial direction of the second bearing can be sufficiently secured, and the second bearing can be disposed close to the engagement point on the output member side with respect to the axial direction of the first axis. . Thereby, the apparatus can be shortened and miniaturized in the axial direction of the first axis while sufficiently increasing the rigidity of the support of the output member.

Further, in the present invention, a cylindrical member (112) including a connecting portion connected to the outer ring so as to be able to rotate together with the outer ring is provided, and the cylindrical member is provided on both sides of the connecting portion of the cylindrical member with the first member. The bearing holding part (138,139) which hold | maintains a 2nd bearing and a 2nd bearing may be included (Claim 5 ).
In this case, the cylindrical member is assembled with the first bearing, the input member supported by the first bearing, the inner ring, the outer ring, the output member, and the second bearing that supports the output member. A subassembly unit is formed. The subassembly unit can be assembled to the housing or the like in a lump, and the assembly of the apparatus can be facilitated.

  In the above description, numbers in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

It is a mimetic diagram showing a schematic structure of a steering device for vehicles provided with a transmission ratio variable mechanism concerning one embodiment of the present invention. It is sectional drawing which shows the more concrete structure of the principal part of FIG. FIG. 3 is an enlarged view of a transmission ratio variable mechanism in FIG. 2 and its surroundings. It is a disassembled perspective view of the principal part of a 1st uneven | corrugated engaging part. It is sectional drawing of the principal part which shows the engagement state of the pin and tooth gap of a 1st uneven | corrugated engaging part. It is an enlarged view of the principal part around the outer ring | wheel of a bearing ring unit.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of a vehicle steering apparatus 1 including a transmission ratio variable mechanism according to an embodiment of the present invention. Referring to FIG. 1, a vehicle steering apparatus 1 applies a steering torque applied to a steering member 2 such as a steering wheel to left and right steered wheels 4L and 4R via a steering shaft 3 as a steering shaft. The steering is given. The vehicle steering apparatus 1 can change a transmission ratio θ2 / θ1 as a ratio of the turning angle θ2 of the second shaft 12 as the steered wheel side member to the steering angle θ1 of the steering member 2. Gear Ratio) function.

The vehicle steering apparatus 1 includes a steering member 2 and a steering shaft 3 connected to the steering member 2. The steering shaft 3 includes first to third shafts 11 to 13 as first to third shafts arranged coaxially with each other. The central axes of the first to third shafts 11 to 13 are also rotation axes of the first to third shafts 11 to 13.
A steering member 2 is connected to one end of the first shaft 11 so as to be able to rotate together. The other end of the first shaft 11 and one end of the second shaft 12 are coupled via a transmission ratio variable mechanism 5 so as to be differentially rotatable. The second shaft 12 and the third shaft 13 are connected to each other via a torsion bar 14 so as to be elastically rotatable relative to each other within a predetermined range and transmit power.

The third shaft 13 is connected to the steered wheels 4L and 4R via the universal joint 7, the intermediate shaft 8, the universal joint 9, the steering mechanism 10, and the like.
The steered mechanism 10 includes a pinion shaft 15 connected to the universal joint 9, and a rack shaft 16 as a steered shaft that has a rack 16a that meshes with the pinion 15a at the tip of the pinion shaft 15 and extends in the left-right direction of the vehicle. Yes. Knuckle arms 18L and 18R are connected to the pair of ends of the rack shaft 16 via tie rods 17L and 17R, respectively.

  With the above configuration, the rotation of the steering member 2 is transmitted to the steering mechanism 10 via the steering shaft 3 and the like. In the turning mechanism 10, the rotation of the pinion 15 a is converted into the axial movement of the rack shaft 16. The axial movement of the rack shaft 16 is transmitted to the corresponding knuckle arms 18L and 18R via the tie rods 17L and 17R, and the knuckle arms 18L and 18R rotate. Accordingly, the corresponding steered wheels 4L and 4R connected to the knuckle arms 18L and 18R are respectively steered.

  The transmission ratio variable mechanism 5 is for changing the rotation transmission ratio (transmission ratio θ2 / θ1) between the first and second shafts 11 and 12 of the steering shaft 3, and is a nutation gear mechanism. . The transmission ratio variable mechanism 5 includes an input member 20 provided at the other end of the first shaft 11, an output member 22 provided at one end of the second shaft 12, and the input member 20 and the output member 22. And a bearing ring unit 39 as an intermediate member interposed therebetween.

The input member 20 is connected to the steering member 2 and the first shaft 11 so that torque can be transmitted. The output member 22 is connected to the second shaft 12 so that torque can be transmitted. The first axis Z1 is the center axis and the rotation axis of the input member 20 and the output member 22, and is the center axis and the rotation axis of the first to third shafts 11 to 13.
The bearing ring unit 39 includes an inner ring 391 as a first bearing ring, an outer ring 392 as a second bearing ring, and rolling elements 393 such as balls interposed between the inner ring 391 and the outer ring 392. Constitutes a ball bearing. An example of the bearing ring unit 391 is a four-point contact bearing. As the rolling element 393, a cylindrical roller, a needle roller, and a tapered roller can be used besides a ball.

  The inner ring 391 connects the input member 20 and the output member 22 so as to be differentially rotatable. The inner ring 391 and the outer ring 392 have a second axis Z2 as a central axis inclined with respect to the first axis Z1. The second axis Z2 is inclined at a predetermined inclination angle A1 with respect to the first axis Z1. The inner ring 391 is rotatably supported by the outer ring 392 via the rolling elements 393, so that the inner ring 391 can rotate around the second axis Z2, and an electric motor as an actuator for driving the outer ring 392 As the transmission ratio variable mechanism motor 23 is driven, it can rotate around the first axis Z1. The inner ring 391 and the outer ring 392 can perform Coriolis motion (swing motion) around the first axis Z1.

The transmission ratio variable mechanism motor 23 is disposed radially outward of the track ring unit 39, and the first axis Z1 is the central axis. The transmission ratio variable mechanism motor 23 changes the transmission ratio θ2 / θ1 by changing the rotation speed of the outer ring 392 around the first axis Z1.
The transmission ratio variable mechanism motor 23 is composed of, for example, a brushless motor, and includes a rotor 231 that holds an outer ring 392 of the raceway ring unit 39 and a stator 232 that surrounds the rotor 231 and is fixed to a housing 24 as a steering column. It is out. The rotor 231 rotates around the first axis Z1.

  The vehicle steering apparatus 1 includes a steering assist force applying mechanism 19 for applying a steering assist force to the steering shaft 3. The steering assist force applying mechanism 19 includes the second shaft 12 as an input shaft continuous with the output member 22 of the transmission ratio variable mechanism 5, the third shaft 13 as an output shaft continuous with the steering mechanism 10, A torque sensor 44 for detecting torque transmitted between the second shaft 12 and the third shaft 13, a steering assist motor 25 as a steering assist actuator, the steering assist motor 25, and a third shaft. 13 and a speed reduction mechanism 26 interposed between them.

The steering assist motor 25 is an electric motor such as a brushless motor. The output of the steering assist motor 25 is transmitted to the third shaft 13 via the speed reduction mechanism 26.
The speed reduction mechanism 26 is composed of, for example, a worm gear mechanism, and is connected to a worm shaft 27 as a drive gear connected to the output shaft 25 a of the steering assist motor 25, meshed with the worm shaft 27 and connected to the third shaft 13 so as to be able to rotate together. And a worm gear 28 as a driven gear. The speed reduction mechanism 26 is not limited to the worm gear mechanism, and other gear mechanisms such as a parallel shaft gear mechanism using a spur gear or a helical gear may be used.

The transmission ratio variable mechanism 5 and the steering assist force applying mechanism 19 are provided in the housing 24. The housing 24 is disposed in a passenger compartment (cabin) of the vehicle. The housing 24 may be disposed so as to surround the intermediate shaft 8 or may be disposed in the engine room of the vehicle.
The driving of the transmission ratio variable mechanism motor 23 and the steering assist motor 25 is controlled by a control unit 29 including a CPU, a RAM, and a ROM, respectively. The control unit 29 is connected to the transmission ratio variable mechanism motor 23 via the drive circuit 40, and is connected to the steering assist motor 25 via the drive circuit 41.

The control unit 29 includes a steering angle sensor 42, a motor resolver 43 as a rotation angle detection means for detecting the rotation angle of the transmission ratio variable mechanism motor 23, a torque sensor 44 as a torque detection means, and a turning angle sensor 45. A vehicle speed sensor 46 and a yaw rate sensor 47 are connected to each other.
A signal about the rotation angle of the first shaft 11 is input from the steering angle sensor 42 to the control unit 29 as a value corresponding to the steering angle θ1 that is an operation amount from the straight traveling position of the steering member 2.

A signal regarding the rotation angle θr of the rotor 231 of the transmission ratio variable mechanism motor 23 is input from the motor resolver 43 to the control unit 29.
A signal about the torque acting between the second and third shafts 12 and 13 is input from the torque sensor 44 to the control unit 29 as a value corresponding to the steering torque T acting on the steering member 2.

A signal about the rotation angle of the third shaft 13 is input from the turning angle sensor 45 to the control unit 29 as a value corresponding to the turning angle θ2.
A signal regarding the vehicle speed V is input from the vehicle speed sensor 46 to the control unit 29.
A signal regarding the yaw rate γ of the vehicle is input from the yaw rate sensor 47 to the control unit 29.

The control unit 29 controls the driving of the transmission ratio variable mechanism motor 23 and the steering assist motor 25 based on the signals of the sensors 42 to 47.
With the above configuration, the output of the transmission ratio variable mechanism 5 is transmitted to the steering mechanism 10 via the steering assist force applying mechanism 19. More specifically, the steering torque input to the steering member 2 is input to the input member 20 of the transmission ratio variable mechanism 5 via the first shaft 11, and the steering assist force applying mechanism 19 of the steering assist force applying mechanism 19 is changed from the output member 22. Is transmitted to the second shaft 12.

The steering torque transmitted to the second shaft 12 is transmitted to the torsion bar 14 and the third shaft 13, and together with the output from the steering assist motor 25, is transmitted to the steering mechanism 10 via the intermediate shaft 8 or the like. The
FIG. 2 is a cross-sectional view showing a more specific configuration of the main part of FIG. Referring to FIG. 2, the housing 24 is formed by, for example, forming a metal such as an aluminum alloy into a cylindrical shape, and includes first to third housings 51 to 53. In the housing 24, first to seventh bearings 31 to 37 are accommodated. The first to fifth bearings 31 to 35 and the seventh bearing 37 are each a rolling bearing such as a ball bearing, and the sixth bearing 36 is a rolling bearing such as a needle roller bearing.

  As the first bearing 31, a four-point contact bearing can be used. The use of the four-point contact bearing is suitable for increasing the rigidity of the support of the first shaft 11 by the first bearing 31 when a bending moment acts on the first shaft 11. As the first bearing 31, other ball bearings such as a deep groove ball bearing may be used. In addition to the balls, rollers such as cylindrical rollers, needle rollers, and tapered rollers can be used as the rolling elements of the first bearing 31.

As the second bearing 32, a four-point contact bearing can be used. The use of the four-point contact bearing is suitable for increasing the rigidity of the support of the second shaft 12 by the second bearing 32 when a bending moment acts on the second shaft 12. Further, as the second bearing 32, other bearings can be used similarly to the first bearing 31.
The first housing 51 has a cylindrical shape, constitutes a differential mechanism housing that houses the transmission ratio variable mechanism 5 as a differential mechanism, and a motor housing that houses the transmission ratio variable mechanism motor 23. It is composed. One end of the first housing 51 is covered with an end wall member 54. One end of the first housing 51 and the end wall member 54 are fixed to each other using a fastening member 55 such as a bolt. An annular convex portion 57 at one end of the second housing 52 is fitted to the inner peripheral surface 56 at the other end of the first housing 51. The first and second housings 51 and 52 are fixed to each other using a fastening member (not shown) such as a bolt.

The second housing 52 has a cylindrical shape, and constitutes a sensor housing that houses the torque sensor 44 and a resolver housing that houses the motor resolver 43. The inner peripheral surface 60 at one end of the third housing 53 is fitted to the outer peripheral surface 59 at the other end of the second housing 52.
The third housing 53 has a cylindrical shape and constitutes a speed reduction mechanism housing that houses the speed reduction mechanism 26. An end wall portion 63 is provided at the other end of the third housing 53. The end wall portion 63 has an annular shape and covers the other end of the third housing 53.

FIG. 3 is an enlarged view of the transmission ratio variable mechanism 5 of FIG. 2 and its surroundings. Referring to FIG. 3, the input member 20, the output member 22 of the transmission ratio variable mechanism 5, and the inner ring 391 of the raceway ring unit 39 each have an annular shape.
The input member 20 is held by the input member main body 201 connected to the first shaft 11, a first extending portion 202 as a connecting portion that can rotate with the input member main body 201, and the input member main body 201. A plurality of pins 77 and an inner holder 75 and an outer holder 76 for holding the plurality of pins 77 by the input member main body 201 are included. The input member main body 201 and the first extending portion 202 are integrally formed using a single material.

The input member main body 201 has a first power transmission surface 70 formed on one end surface facing the inner ring 391 of the raceway ring unit 39 and a radially inner side of the input member 20 with respect to the first power transmission surface 70. 1st fitting part 201a arrange | positioned.
The other end of the first shaft 11 is inserted into the first fitting portion 201a, and both are connected so as to be able to transmit torque, for example, by serration fitting.

The first extending portion 202 is orthogonal to the input member main body 201 in the orthogonal direction Y1 (hereinafter also simply referred to as the orthogonal direction Y1) that is orthogonal to the axial direction S1 of the first axis Z1 (hereinafter also simply referred to as the axial direction S1). It has a disk shape extending outward. At least a part of the first extending portion 202 is disposed so as to overlap the input member main body 201 with respect to the axial direction S1.
The outer diameter portion 202 a of the first extending portion 202 includes a first bearing inner ring holding portion 121 into which the inner ring 31 a of the first bearing 31 is fitted, and a bearing ring unit with respect to the first bearing inner ring holding portion 121. The first step portion 122 is disposed on the inner ring 391 side of the first bearing 31 and receives the other end surface of the inner ring 31a of the first bearing 31. The first step portion 122 restricts the inner ring 31a of the first bearing 31 from moving to the other S12 side in the axial direction S1 with respect to the input member 20.

A first accommodating recess 123 is formed in the first facing end surface 202 b of the first extending portion 202 facing the outer ring 392 of the raceway ring unit 39.
The 1st accommodation recessed part 123 is an annular recessed part formed by denting the 1st opposing end surface 202b. The bottom surface 123a of the first housing recess 123 is orthogonal to the first axis Z1. A side surface 123b of the first receiving recess 123 connected to the outer diameter portion of the bottom surface 123a is formed in a taper shape, and the diameter increases as it proceeds to the other S12 in the axial direction S1. An inner diameter portion of the bottom surface 123 a is continuous with the input member main body 201.

The output member 22 has a shape that is substantially symmetrical to the input member 20 in the axial direction S1.
The output member 22 is formed in an annular shape, and the output member main body 221 connected to the second shaft 12, the second extending portion 222 as a connecting portion that can rotate together with the output member main body 221, and the output A plurality of pins 87 held by the member main body 221 and an inner holder 85 and an outer holder 86 for holding the plurality of pins 87 by the output member main body 221 are included. The output member main body 221 and the second extending portion 222 are integrally formed using a single material.

The output member main body 221 has a second power transmission surface 73 formed on one end surface facing the inner ring 391 of the raceway ring unit 39 and a radially inner side of the output member 22 with respect to the second power transmission surface 73. And a second fitting portion 221a arranged.
One end of the second shaft 12 is inserted into the second fitting portion 221a, and both are coupled so as to be able to transmit torque by, for example, serration fitting.

The second extending portion 222 has a disk shape extending outward in the orthogonal direction Y1 with respect to the output member main body 221. At least a part of the second extending portion 222 is disposed so as to overlap the output member main body 221 with respect to the axial direction S1.
The outer diameter portion 222 a of the second extending portion 222 includes a second bearing inner ring holding portion 125 into which the inner ring 32 a of the second bearing 32 is fitted, and a bearing ring unit with respect to the second bearing inner ring holding portion 125. And a second step 126 that receives one end surface of the inner ring 32a of the second bearing 32. The second step 126 restricts the inner ring 32a of the second bearing 32 from moving toward the one side S11 in the axial direction S1 with respect to the output member 22.

A second accommodating recess 127 is formed on the second facing end surface 222 b of the second extending portion 222 that faces the outer ring 392 of the raceway ring unit 39.
The second accommodation recess 127 is an annular recess formed by recessing the second opposing end surface 222b. The bottom surface 127a of the second housing recess 127 is orthogonal to the first axis Z1. A side surface 127b of the second accommodation recess 127 connected to the outer diameter portion of the bottom surface 127a of the second accommodation recess 127 is formed in a taper shape, and the diameter increases as it advances to one S11 in the axial direction S1. Yes. An inner diameter portion of the bottom surface 127 a is continuous with the output member main body 221.

The inner ring 391 of the track ring unit 39 is integrally formed using a single member, and is disposed between the input member 20 and the output member 22.
The outer ring 392 is connected to the rotor 231 of the transmission ratio variable mechanism motor 23 and rotates together with the rotor 231 around the first axis Z1. As the rotor 231 rotates around the first axis Z1, the bearing ring unit 39 performs Coriolis motion.

  The inner ring 391 includes a first end surface 71 that faces the first power transmission surface 70 of the input member 20, and a second end surface 72 that faces the second power transmission surface 73 of the output member 22. . The first end surface 71 and the second end surface 72 are parallel to each other and orthogonal to the axial direction S2 of the second axis Z2. The first end surfaces 71 are opposed to each other while being inclined with respect to the first power transmission surface 70. The second end surfaces 72 are opposed to each other while being inclined with respect to the second power transmission surface 73.

A first concavo-convex engaging portion 61 is provided on the first power transmission surface 70 of the input member 20 and the first end surface 71 of the inner ring 391 of the bearing ring unit 39.
Further, a second uneven engagement portion 62 is provided on the second end surface 72 of the inner ring 391 of the bearing ring unit 39 and the second power transmission surface 73 of the output member 22.
FIG. 4 is an exploded perspective view of a main part of the first concave-convex engaging portion 61. Referring to FIGS. 3 and 4, first concavo-convex engaging portion 61 engages first power transmission surface 70 and first end surface 71 so that power can be transmitted.

The first concavo-convex engaging portion 61 includes a plurality of holding grooves 79 formed in the first power transmission surface 70, a plurality of pins 77 as convex portions held in the holding grooves 79, and the bearing ring unit 39. And a tooth groove 80 as a plurality of recesses formed on the first end surface 71 of the inner ring 391 and engaged with the corresponding pin 77.
The input member 20 is provided with a holding groove 79 and a pin 77. A tooth groove 80 is provided in the inner ring 391 of the bearing ring unit 39.

In addition, the holding groove 79 and the pin 77 may be provided in the inner ring 391 of the bearing ring unit 39, and the tooth groove 80 may be provided in the input member 20.
The holding groove 79, the pin 77, and the tooth groove 80 are arranged at equal intervals over the entire area in the circumferential direction on the corresponding first power transmission surface 70 and first end surface 71, respectively.
Each pin 77 is, for example, a needle roller having a cylindrical shape. These pins 77 are arranged radially about the first axis Z1. As shown in FIG. 5, half of each pin 77 protrudes from the corresponding holding groove 79 to form a semicircular cross section, and this protruding half engages with the tooth groove 80. The tooth gap 80 corresponding to the pin 77 meshes with a pair of engaging points P1, P1 on both sides of the bottom of the tooth gap 80 as a center. Since these engagement points P1 and P1 are minute regions, it can be considered that they are substantially at the same place.

Referring to FIGS. 3 and 4 again, a single portion of each pin 77 on the outer side in the radial direction of input member 20 is rotatably held by an annular outer retainer 76 (not shown in FIG. 4). Has been. Further, the radially inner end of the input member 20 is held by an annular inner cage 75 (not shown in FIG. 4) so as to be able to rotate.
The tooth gap 80 is formed radially and elongated around the second axis Z2. The number of tooth spaces 80 is the same as or different from the number of pins 77. Depending on the difference between the number of pins 77 and the number of tooth gaps 80, a shift can be performed between the input member main body 201 and the inner ring 391. Some pins 77 and some tooth gaps 80 mesh with each other.

Referring to FIG. 3, second uneven engagement portion 62 engages second power transmission surface 73 and second end surface 72 so as to transmit power.
The second concavo-convex engaging portion 62 includes a plurality of holding grooves 109 formed on the second power transmission surface 73, pins 87 as a plurality of convex portions held in the holding grooves 109, and a second end surface. And a tooth groove 110 as a plurality of recesses that are formed in 72 and engage with corresponding pins 87.

The output member 22 is provided with a holding groove 109 and a pin 87. A tooth groove 110 is provided in the inner ring 391 of the bearing ring unit 39.
The inner ring 391 may be provided with the holding groove 109 and the pin 87, and the output member 22 may be provided with the tooth groove 110.
The holding groove 109 and the pin 87 of the second concavo-convex engaging part 62 have the same configuration as the holding groove 79 and the pin 77 of the first concavo-convex engaging part 61. Further, the tooth groove 110 of the second uneven engagement portion 62 has the same configuration as the tooth groove 80 of the first uneven engagement portion 61. Therefore, the detailed description of the second uneven engagement portion 62 is omitted. The pin 87 and the tooth gap 110 are engaged around the engagement point P2. The distance between the engagement point P2 of the second uneven engagement portion 62 and the first axis Z1 and the distance between the engagement point P1 of the first uneven engagement portion 61 and the first axis Z1 are substantially the same. is there.

Further, an inner holder 85 and an outer holder 86 for holding the pin 87 of the second concave / convex engaging portion 62 are provided. Since these retainers 85 and 86 have the same configuration as the corresponding inner retainer 75 and outer retainer 76, detailed description thereof is omitted.
FIG. 6 is an enlarged view of a main part around the outer ring 392. Referring to FIG. 6, outer ring 392 of raceway ring unit 39 includes an outer ring main body 129 and an outer ring extending portion 130 to which outer ring main body 129 is fixed. The outer ring main body 129 and the outer ring extending portion 130 are formed separately, but may be integrally formed using a single material.

The outer ring main body 129 has an annular shape and is disposed coaxially with the inner ring 391 of the raceway ring unit 39. The outer ring main body 129 supports the inner ring 391 via the rolling elements 393. Thus, the inner ring 391 can rotate around the second axis Z2 with respect to the outer ring main body 129.
The outer ring extending portion 130 connects the outer ring main body 129 and the rotor 231 of the transmission ratio variable mechanism motor 23 so as to be able to rotate around the first axis Z1. The outer ring extending portion 130 includes a relatively thick portion 131 and a relatively thin portion 132 in the axial direction S1.

  The thick part 131 constitutes an inner diameter part of the outer ring extending part 130. A fitting portion 133 to which the outer peripheral surface of the outer ring main body 129 is fixed is formed on the inner periphery of the intermediate portion of the thick portion 131 in the axial direction S1. An annular step portion 134 and a holding groove 135 are formed on the inner periphery of the thick portion 131 with the fitting portion 133 interposed therebetween. A retaining ring 136 is retained in the retaining groove 135, and the outer ring main body 129 is sandwiched between the annular step 134 and the retaining ring 136 in the axial direction S <b> 1.

One end 131a of the thick wall 131 in the axial direction S1 is housed in the first housing recess 123 of the input member 20. One end surface 131b of the thick portion 131 is opposed to the bottom surface 123a of the first housing recess 123 and the side surface 123b of the first housing recess 123 with a predetermined gap therebetween.
The other end 131c of the thick portion 131 in the axial direction S1 is accommodated in the second accommodation recess 127 of the output member 22. The other end surface 131d of the thick portion 131 faces the bottom surface 127a of the second housing recess 127 and the side surface 127b of the second housing recess 127 with a predetermined gap therebetween.

  The thin portion 132 is continuous with the outer diameter portion of the thick portion 131 and has an annular shape. The outer diameter portion 132 a of the thin portion 132 is connected to a connection portion 112 b formed on the inner diameter portion 112 a of the cylindrical rotor core 112 of the rotor 231 of the transmission ratio variable mechanism motor 23. The thin portion 132 and the rotor core 112 are integrally formed using a single material, and can rotate together around the first axis Z1. Note that the thin portion 132 and the rotor core 112 may be formed as separate bodies, and both may be coupled so as to be able to rotate along the first axis Z1.

  The outer ring 31 b of the first bearing 31 is fitted in a first bearing outer ring holding part 138 formed in the inner diameter part 112 a of the rotor core 112. Further, the inner ring 31a of the first bearing 31 is fitted to the first bearing inner ring holding portion 121 of the input member 20 as described above. As a result, the rotor core 112 supports the input member 20 via the first bearing 31 so as to be rotatable around the first axis Z1.

  The outer ring 32 b of the second bearing 32 is fitted in a second bearing outer ring holding part 139 formed in the inner diameter part 112 a of the rotor core 112. Further, as described above, the inner ring 32 a of the second bearing 32 is fitted to the second bearing inner ring holding portion 125 of the output member 22. As a result, the rotor core 112 supports the output member 22 via the second bearing 32 so as to be rotatable around the first axis Z1.

The first bearing outer ring holding portion 138 and the second bearing outer ring holding portion 139 are arranged with the connecting portion 112b sandwiched in the axial direction S1.
With reference to FIG. 3, one of the features of the present embodiment is that the distance from the first axis Z <b> 1 of the radially inner ends of the first bearing 31 and the second bearing 32 in the orthogonal direction Y <b> 1. X1 and X2 are at longer points than the distances X3 and X4 from the first axis Z1 of the engaging points P1 and P2 of the first and second concave and convex engaging portions 61 and 62 (X1> X3 and X1> X4, X2> X3 and X2> X4). In the present embodiment, the distance X3 and the distance X4 are substantially equal.

Specifically, the inner peripheral surface of the inner ring 31a of the first bearing 31 is disposed outside the first extending portion 202 with respect to the orthogonal direction Y1. Similarly, the inner peripheral surface of the inner ring 32a of the second bearing 32 is disposed outside the second extending portion 222 with respect to the orthogonal direction Y1.
Further, the engagement point P1 of the first bearing 31 and the first uneven engagement portion 61 is disposed so as to overlap with each other in the axial direction S1. More specifically, the other end portion of the inner ring 31a and the outer ring 31b of the first bearing 31 as the end portion on the other S12 side in the axial direction S1 and the engagement point P1 of the first uneven engagement portion 61 are They are arranged so as to overlap with respect to the direction S1.

Similarly, the second bearing 32 and the engagement point P2 of the second uneven engagement portion 62 are arranged so as to overlap with each other in the axial direction S1. More specifically, the engagement between the one end portion of the inner ring 32a of the second bearing 32 and the outer ring 32b of the second bearing 32 as one end portion on the one S11 side in the axial direction S1 and the second concave-convex engaging portion 62. The matching point P2 is arranged so as to overlap with respect to the axial direction S1.
Further, in the reference plane F1 (plane shown in FIG. 3) including the first axis Z1, the engagement point P1 of the first uneven engagement portion 61, and the engagement point P2 of the second uneven engagement portion 62, the first The bearing 31 is disposed between the first inclined line L1 and the orthogonal line L3. In the reference plane F1, the first inclined line L1 is a straight line that passes through both the engagement points P1 and P2 of the first and second concavo-convex engaging portions 61 and 62 and is inclined with respect to the first axis Z1. In the reference plane F1, the orthogonal line L3 is a straight line that passes through the intersection P3 of the first inclined line L1 and the first axis Z1 and is orthogonal to the first axis Z1.

In the reference plane F1, the second bearing 32 is disposed between the second inclined line L2 and the orthogonal line L3. In the reference plane F1, the second inclined line L2 is a straight line that is symmetrically arranged around the orthogonal line L3 with respect to the first inclined line L1.
A preload is applied to the first bearing 31 and the first concave-convex engaging portion 61 by the first biasing member 141. In addition, a preload is applied to the second bearing 32 and the second concavo-convex engaging portion 62 by the second urging member 142. Preloading the first bearing 31 and the first uneven engagement portion 61 by the first biasing member 141 and the second bearing 32 and the second uneven engagement portion 62 by the second biasing member 142 are performed. It is independent of the preload.

  Specifically, the first biasing member 141 is an annular elastic member such as a disc spring. The outer diameter portion of the first urging member 141 is fitted and held in a first holding groove 143 formed in the inner diameter portion 112a of the rotor core 112 as a holding member. The first biasing member 141 is in contact with one end surface of the outer ring 31b of the first bearing 31, and biases the outer ring 31b of the first bearing 31 toward the other S12 side in the axial direction S1. Thereby, the urging force of the first urging member 141 causes the outer ring 31 b of the first bearing 31, the rolling element of the first bearing 31, the inner ring 31 a of the first bearing 31, and the first extension of the input member 20. It acts on the engagement point P <b> 1 between the pin 77 and the tooth groove 80 of the first concave / convex engagement portion 61 via the portion 202 and the input member main body 201. As a result, preload is applied to the first bearing 31 and the first concave-convex engaging portion 61. In this way, the first power transmission surface 70 is urged toward the first end surface 71.

  The second urging member 142 is an annular elastic member such as a disc spring. The outer diameter portion of the second urging member 142 is fitted and held in a second holding groove 144 formed in the inner diameter portion 112a of the rotor core 112 as a holding member. The second urging member 142 and the first urging member 141 are disposed outside the second bearing 32 and the first bearing 31 in the axial direction S1. The second urging member 142 is in contact with the other end surface of the outer ring 32b of the second bearing 32, and urges the outer ring 32b of the second bearing 32 toward one S11 side in the axial direction S1. Thereby, the urging force of the second urging member 142 causes the outer ring 32 b of the second bearing 32, the rolling element of the second bearing 32, the inner ring 32 a of the second bearing 32, and the second extension of the output member 22. Through the portion 222 and the output member main body 221, it acts on the engagement point P2 between the pin 87 of the second uneven engagement portion 62 and the corresponding tooth groove 110. As a result, a preload is applied to the second bearing 32 and the second concave-convex engaging portion 62. In this way, the second power transmission surface 73 is biased toward the second end surface 72 side.

Referring to FIG. 2, the rotor 231 of the transmission ratio variable mechanism motor 23 includes a rotor core 112 as a cylindrical connecting member extending in the axial direction S <b> 1 and a permanent magnet 113 fixed to the outer peripheral surface of the rotor core 112. It is out.
Both ends of the rotor core 112 are supported at both ends by third and fourth bearings 33 and 34 sandwiching the first and second bearings 31 and 32 in the axial direction S1.

The third bearing 33 is held by an annular convex portion 114 formed on the inner diameter portion of one end of the first housing 51. The fourth bearing 34 is held by an annular extending portion 115 formed at the inner diameter portion of the other end of the second housing 52.
The annular extending portion 115 has a cylindrical shape extending from the partition wall portion 116 provided at the other end of the second housing 52 toward the one side S11 in the axial direction S1, and the rotor core 112 is inserted therethrough.

The stator 232 of the transmission ratio variable mechanism motor 23 is fixed to the inner peripheral surface of the first housing 51 by shrink fitting or the like, and surrounds the permanent magnet 113 of the rotor 231.
The motor resolver 43 includes a resolver rotor 117 and a resolver stator 118. The resolver rotor 117 is fixed to the outer peripheral surface of the other end of the rotor core 112. The resolver stator 118 is fixed to the inner peripheral surface of the second housing 52.

The torque sensor 44 is disposed radially inward of the rotor core 112 of the transmission ratio variable mechanism motor 23.
A fifth bearing 35 is disposed on the other side S12 in the axial direction S1 with respect to the torque sensor 44. The fifth bearing 35 is held by the partition wall 116 of the second housing 52 and rotatably supports one end of the third shaft 13.

The 2nd shaft 12 and the 3rd shaft 13 are mutually supported through the 6th bearing 36 so that relative rotation is possible.
A seventh bearing 37 is interposed between the intermediate portion of the third shaft 13 and the end wall portion 63 of the third housing 53. The end wall portion 63 supports the third shaft 13 through the seventh bearing 37 so as to be rotatable.

With the above configuration, the rotor core 112, the third bearing 33, the first biasing member 141, the first bearing 31, the input member 20, the bearing ring unit 39, the output member 22, the second bearing 32, the second bearing The biasing member 142 and the fourth bearing 34 constitute a subassembly unit 145.
As described above, according to the present embodiment, the distances X1 and X2 from the first axis Z1 with respect to the first bearing 31 and the second bearing 32 are respectively determined as the first and second uneven engagement portions. The engagement points P1 and P2 of 61 and 62 are longer than the distances X3 and X4 from the first axis Z1. As a result, the first and second bearings 31 and 32 are arranged sufficiently spaced from the first axis Z1, and a space on the radially inner side of the first and second bearings 31 and 32 is sufficiently secured. it can.

Thereby, the space which arrange | positions the corresponding input member 20 and the output member 22 in the radial inside of the 1st bearing 31 and the 2nd bearing 32 is fully securable. Therefore, the corresponding input member 20 and output member 22 can be arranged so that the dead space inside the radial direction of the first bearing 31 and the second bearing 32 is reduced.
As a result, the vehicle steering apparatus 1 can be downsized through downsizing by shortening the transmission ratio variable mechanism 5 with respect to the axial direction S1. Moreover, the thickness of the radial direction of the 1st bearing 31 and the 2nd bearing 32 can fully be ensured, achieving size reduction of the steering device 1 for vehicles. Thereby, the rigidity of the support of the corresponding input member 20 and output member 22 by the first bearing 31 and the second bearing 32 can be sufficiently secured.

  As a result, the pin 77 and the tooth groove 80 of the first concavo-convex engaging portion 61 can be more reliably maintained in a highly accurate meshing state, and the pin 87 and the tooth groove 110 of the second concavo-convex engaging portion 62 can be maintained. The highly accurate meshing state can be maintained more reliably. Thereby, it can prevent that the engagement sound of the pin 77 and the tooth groove 80 becomes large, and can prevent that the engagement sound of the pin 87 and the tooth groove 110 becomes large.

  Further, one end 131 a of the thick portion 131 of the outer ring 392 of the bearing ring unit 39 is accommodated in the first accommodation recess 123, and the other end 131 b is accommodated in the second accommodation recess 127. Thereby, regarding the axial direction S1, the first bearing 31 and the second bearing 32, and the corresponding input member 20 and output member 22 can be arranged in an overlapping manner. Thereby, regarding the axial direction S1, the vehicle steering device 1 can be further shortened and miniaturized.

  Further, the first urging member 141 can press the pin 77 of the first concavo-convex engagement portion 61 toward the tooth groove 80, whereby a preload can be applied to the first concavo-convex engagement portion 61. As a result, rattling between the pin 77 and the tooth groove 80 can be prevented. As a result, the engagement between the pin 77 and the tooth groove 80 can be made smoother. In addition, preload can be applied to the first bearing 31, and vibration and noise caused by the first bearing 31 can be reduced.

  Similarly, the second urging member 142 can press the pin 87 of the second concavo-convex engaging portion 62 toward the tooth gap 110 to apply a preload to the second concavo-convex engaging portion 62. . As a result, rattling of the pin 87 and the tooth gap 110 can be prevented. As a result, the engagement between the pin 87 and the tooth gap 110 can be made smoother. In addition, a preload can be applied to the second bearing 32, and vibration and noise caused by the second bearing 32 can be reduced.

  Furthermore, the first urging member 141 and the second urging member 142 are arranged with the outer ring 392 of the raceway ring unit 39 sandwiched in the axial direction S1. As a result, the preload is applied to the first concave / convex engaging portion 61 using the first biasing member 141 and the preload is applied to the second concave / convex engaging portion 62 using the second biasing member 142. Grant is independent of each other. As a result, the urging force of the first urging member 141 and the urging force of the second urging member 142 can be prevented from interfering with each other. Therefore, the preload to the first bearing 31 and the first uneven engagement portion 61 can be set with high accuracy, and the preload to the second bearing 32 and the second uneven engagement portion 62 can be set with high accuracy.

The first bearing 31 is disposed so as to overlap with the engagement point P1 of the first uneven engagement portion 61 with respect to the axial direction S1, and the second bearing 32 is provided on the second uneven engagement portion 62. The engagement point P2 is overlapped with respect to the axial direction S1.
Thereby, the 1st bearing 31 and the 2nd bearing 32, and the corresponding engagement points P1 and P2 can be opposed to the orthogonal direction Y1. Thereby, the 1st bearing 31 and the 2nd bearing 32 can each receive the radial load which acts on corresponding engagement point P1, P2 reliably. As a result, the rigidity of the support of the corresponding input member 20 and output member 22 by the first bearing 31 and the second bearing 32 can be further increased.

Further, in the reference plane F1, the first bearing 31 is disposed between the first inclined line L1 and the orthogonal line L3, and the second bearing is interposed between the second inclined line L2 and the orthogonal line L3. 32 is arranged.
Thereby, the thickness of the 1st bearing 31 regarding the radial direction of the 1st bearing 31 can fully be ensured, and the engagement point P1 of the 1st uneven | corrugated engaging part 61 is connected to the 1st bearing 31 regarding the axial direction S1. Can be placed close to. As a result, the vehicle steering device 1 can be shortened and miniaturized in the axial direction S1 while the rigidity of the support of the input member 20 is sufficiently increased. Moreover, the thickness of the second bearing 32 in the radial direction of the second bearing 32 can be sufficiently secured, and the second bearing 32 is set to the engagement point P2 of the second uneven engagement portion 62 in the axial direction S1. Can be placed close together. As a result, the vehicle steering apparatus 1 can be shortened and miniaturized in the axial direction S1 while the rigidity of the support of the output member 22 is sufficiently increased.

  Further, the other end of the first shaft 11 is supported by the first bearing 31 as one single row bearing, so that the transmission ratio variable mechanism 5 can be compared with the case where the other end is supported by a plurality of bearings. The length in the axial direction S1 can be made shorter. Similarly, by supporting one end of the second shaft 12 by the second bearing 32 as one single row bearing, the transmission ratio variable mechanism 5 can be compared with the case where the one end is supported by a plurality of bearings. The length in the axial direction S1 can be further shortened.

  Further, the rotor core 112 is provided with the third bearing 33, the first biasing member 141, the first bearing 31, the input member 20, the bearing ring unit 39, the output member 22, and the second bearing 32. A sub-assembly unit 145 is formed by assembling the second urging member 142 and the fourth bearing 34. The subassembly unit 145 can be assembled to the housing 24 in a lump, and the vehicle steering apparatus 1 can be assembled more easily.

The present invention is not limited to the contents of the above-described embodiment, and various modifications can be made within the scope of the claims.
For example, the first urging member 141 is used to apply preload to the first bearing 31 and the first concave / convex engaging portion 61, but the present invention is not limited thereto. As long as the preload can be applied to the first bearing 31 and the first concave-convex engagement portion 61, a configuration having another general urging member and a holding member that holds the urging member may be used. Similarly, the second urging member 142 is used to apply preload to the second bearing 32 and the second concave / convex engaging portion 62, but the present invention is not limited to this. As long as a preload can be applied to the second bearing 32 and the second concave-convex engaging portion 62, a configuration having another general urging member and a holding member that holds the urging member may be used.

  Further, only one of the distance X1 related to the first bearing 31 and the distance X2 related to the second bearing 32 is set to the distance X3 related to the engagement points P1 and P2 of the first and second concavo-convex engaging portions 61 and 62, respectively. , X4 may be longer. In this case, for example, the diameter of the first bearing inner ring holding part 121 of the input member 20 is made smaller, the diameter of the first bearing outer ring holding part 138 of the rotor core 112 is made smaller, and the first bearing 31 of the first bearing 31 is further reduced. By making the inner ring 31a and the outer ring 31b smaller in diameter, the distance X1 related to the first bearing 31 is made shorter than the distances X3 and X4 related to the engagement points P1 and P2.

  Further, for example, the diameter of the second bearing inner ring holding portion 125 of the output member 22 is made smaller, the diameter of the second bearing outer ring holding portion 139 of the rotor core 112 is made smaller, and the inner ring of the second bearing 32 is further reduced. By making the diameter of 32a and the outer ring 32b smaller, the distance X2 related to the second bearing 32 is made shorter than the distances X3 and X4 related to the engagement points P1 and P2.

  Further, in each of the above-described embodiments, the example in which the steering assist motor 25 is applied to the column type electric power steering apparatus in which the steering assist motor 25 is disposed in the steering column has been described. However, the present invention is not limited to this. For example, the present invention may be applied to a rack assist type electric power steering apparatus in which the steering assist motor 25 is provided in the steering rack housing. Further, the present invention may be applied to a pinion assist type electric power steering apparatus in which the steering assist motor 25 is disposed on the pinion shaft 15.

  Further, in each of the above embodiments, the example in which the transmission ratio variable mechanism 5 is disposed on the steering shaft 3 has been described. However, the transmission ratio variable mechanism 5 may be disposed on the intermediate shaft 8 or the pinion shaft 15.

DESCRIPTION OF SYMBOLS 1 ... Vehicle steering device, 2 ... Steering member, 5 ... Transmission ratio variable mechanism, 12 ... 2nd shaft (steering wheel side member), 20 ... Input member, 22 ... Output member, 23 ... Transmission ratio variable mechanism motor (Actuator), 31 ... first bearing, 32 ... second bearing, 61 ... first uneven engagement part, 62 ... second uneven engagement part, 70 ... first power transmission surface, 71 ... first 1 end face, 72 ... second end face, 73 ... second power transmission face, 77 ... pin (first concave / convex engaging part) convex part, 80 ... tooth groove (first concave / convex engaging part concave part) ), 87... Pin (convex portion of the second concavo-convex engaging portion), 110... Tooth space (concave portion of the second concavo-convex engaging portion), 112... Rotor core (cylindrical member), 112 b (of the cylindrical member) Connecting portion, 123... First receiving recess (for input member), 127... Second receiving recess for (output member), 138... First bearing outer ring holding portion (bearing) Holding part), 139 ... second bearing outer ring holding part (bearing holding part), 141 ... first biasing member, 142 ... second biasing member, 202 ... first extension part (connecting part of input member) ), 202b (first input end surface) of the input member, 222 ... second extending portion (connecting portion of the output member), 222b (second output end surface) of the output member, 391 ... (of the bearing ring unit) ) Inner ring, 392... Outer ring (of race ring unit), 393... Rolling element (of race ring unit), F 1. Reference plane (plane), L 1. First slope line, L 2 ... Second slope line, L 3. Orthogonal line, P1... Engagement point (of the first concavo-convex engagement portion), P2... Engagement point (of the second concavo-convex engagement portion), P3... Intersection, S1... Axial direction, X1 to X4. Orthogonal direction, Z1... First axis, Z2... Second axis, .theta.1... Steering angle, .theta.2... Steering angle, .theta.2 / .theta.1.

Claims (5)

In a vehicle steering apparatus including a transmission ratio variable mechanism capable of changing a transmission ratio as a ratio of a turning angle of a steered wheel side member to a steering angle of a steering member,
The transmission ratio variable mechanism includes an input member that is connected to a steering member and is rotatable about a first axis, an output member that is connected to a steered wheel side member and is rotatable about a first axis, and first and second members. An inner ring that connects the input member and the output member so as to be differentially rotatable, an outer ring that rotatably supports the inner ring via a rolling element, an actuator that can rotationally drive the outer ring, and the input member A first bearing that rotatably supports the second bearing, and a second bearing that rotatably supports the output member;
A second axis as a central axis of the inner ring and the outer ring is inclined with respect to the first axis;
The input member and the output member have a power transmission surface facing the corresponding end surface of the inner ring,
An uneven engagement portion is provided for engaging each end face of the inner ring and a power transmission surface corresponding to the end face so as to be able to transmit power,
The concavo-convex engaging portion includes a convex portion provided on one of the end surfaces and the power transmission surface corresponding to the end surface, and a concave portion that is provided on the other and engages at a predetermined engagement point with the convex portion.
With respect to the orthogonal direction orthogonal to the first axis, the distance from the first axis of at least one of the first and second bearings is the first of the engagement points of the concavo-convex engagement portions. long rot than the distance from the axis,
The at least one of the first and second bearings is connected to a connecting portion provided in a corresponding input member and output member,
The vehicular steering apparatus according to claim 1, wherein the connecting portion has a facing end surface facing the outer wheel, and an annular housing recess for housing a part of the outer wheel is formed on the facing end surface . According to claim 1, comprising a biasing member through the bearing that is connected to the connecting portion and the connecting portion, it urges the power transmission surface of the member that is supported on the bearing inner ring of the corresponding end face A vehicle steering apparatus characterized by the above. In Claim 1 or 2 , said at least one of said 1st and 2nd bearing and said engaging point by the side of a corresponding input member and output member are overlapped and arrange | positioned regarding the axial direction of said 1st axis. A vehicle steering apparatus. The distance from the first axis of each of the first and second bearings with respect to the orthogonal direction according to any one of claims 1 to 3 is an engagement point of each of the concave and convex engaging portions. Longer than the distance from the first axis,
In a plane including the engagement points of the first axis and the concave and convex engaging portions, a first inclination line that passes through each of the engagement points and is inclined with respect to the first axis, a first inclination line, and The first bearing is disposed between an orthogonal line passing through the intersection of the first axes and orthogonal to the first axis,
In the above plane, the first inclined line is a vehicle in which a second bearing is disposed between the second inclined line symmetrically arranged around the orthogonal line and the orthogonal line. Steering device. In any 1 item | term of Claims 1-4 , The cylindrical member containing the connection part connected with the said outer ring | wheel so that rotation along with the said outer ring is possible,
The above-mentioned cylindrical member includes a bearing holding portion that holds the first bearing and the second bearing on both sides of the connecting portion of the cylindrical member.

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