JP5110361B2 - Transmission ratio variable mechanism and vehicle steering apparatus including the same - Google Patents

Description

  The present invention relates to a transmission ratio variable mechanism and a vehicle steering apparatus including the same.

A transmission ratio variable mechanism capable of changing a transmission ratio as a ratio of an output rotation angle to an input rotation angle is known (for example, see Patent Documents 1 and 2).
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 JP 2007-170624 A

Since the second and third gears are formed at both ends of the outer ring gear portion of the swing gear, the diameters of the second and third gears are large. Accordingly, the radial support span is long when the outer ring gear portion is supported by the first and fourth gears from both sides in the axial direction, and the support rigidity of the outer ring gear portion is lowered.
Further, as a result of the diameters of the second and third gears being increased, the peripheral speed when the second and third gears are driven is high, and the meshing noise is increased.

  The present invention has been made under such a background, and a transmission ratio variable mechanism capable of increasing the rigidity of the support related to the transmission ratio variable mechanism and reducing driving noise, and a vehicle steering equipped with the same. An object is to provide an apparatus.

  In order to achieve the above object, the present invention includes an input member (20) and an output member (22) rotatable around a first axis (A), and first and second end faces (71, 73). An inner ring (391) that connects the input member and the output member so as to be differentially rotatable, an outer ring (392) that rotatably supports the inner ring via a rolling element (393), and the outer ring can be driven to rotate. A second axis (B) as a central axis of the inner ring and the outer ring is inclined with respect to the first axis, and each of the input member and the output member corresponds to the inner ring. There are provided power transmission surfaces (70, 72) opposed to the end surfaces to be engaged, and concave and convex engaging portions (64, 67) for engaging the power transmission surfaces corresponding to the respective end surfaces of the inner ring and the end surfaces so as to be able to transmit power are provided. The concavo-convex engaging portion is provided on each end face and the end face. And a convex portion (65, 68; 65A) provided on one side of the corresponding power transmission surface and a concave portion (66, 69; 66A; 66B) provided on the other side and engaged with the convex portion. A transmission ratio variable mechanism (5) is provided (claim 1).

  According to the present invention, the concave and convex engaging portions are provided on the relatively small-diameter inner ring side of the inner ring and the outer ring, so that the inner ring is supported in the radial direction by the input member and the output member from both sides in the axial direction. The support span can be shortened. Thereby, the support rigidity of an inner ring can be made high. Moreover, the convex part or recessed part of an uneven | corrugated engaging part is provided in the inner ring | wheel side with a relatively small diameter among an inner ring | wheel and an outer ring | wheel. Thereby, the peripheral speed at the time of the drive of the convex part or recessed part provided in the inner ring can be made small, and the engagement sound of an uneven | corrugated engaging part can be made small.

  In the present invention, the actuator includes an electric motor (23), and the electric motor has a rotor (231) that holds the outer ring so as to be able to rotate together and is rotatable around a first axis. There is a case (Claim 2). In this case, the outer ring can be surrounded by the rotor, and the meshing sound of the concave and convex engaging portion can be suppressed from being transmitted to the outside of the rotor, and the noise can be further reduced.

In the present invention, the rotor may be formed with an inclined hole (63) having a central axis along the second axis and holding the outer ring (claim 3). In this case, by holding the outer ring in the inclined hole of the rotor, the second axis as the central axis of the outer ring can be inclined with respect to the first axis.
In the present invention, the rotor is supported by a pair of bearings (32, 34) held by a housing (24), and the inner ring is disposed between the pair of bearings in the axial direction of the rotor. (Claim 4). In this case, the rotor can be supported at both ends by a pair of bearings, and the rigidity of the support of the rotor can be increased. Further, by disposing the inner ring between the pair of bearings, it is possible to firmly support the rotor that receives a force from the inner ring, and to prevent the rotor from running out. As a result, it can contribute to noise reduction.

  In the present invention, the insertion hole (202a) formed in the input member is inserted through the first shaft (11) that is connected to the input member so as to be rotatable along with the input member, and the insertion hole (22a) formed in the output member. A support mechanism for supporting the second shaft (12), which is connected to the insertion output member so as to be able to rotate together, and the opposing ends (11a, 12a) of the first and second shafts so as to be relatively rotatable relative to each other. (133) may be provided (claim 5).

In this case, the concentricity of the first and second axes can be improved by coaxially supporting the opposing ends of the first and second axes. As a result, the centering of the input member and the output member with respect to each other can be prevented, and the engagement state between the convex portion and the concave portion in each concave and convex engaging portion can be suppressed from being changed carelessly, and the engagement sound can be increased. Can be prevented.
In the present invention, the support mechanism surrounds the opposing ends of the first and second shafts, and is connected to one of the first shaft and the second shaft so as to be able to rotate together. 202D) and a bearing (38) interposed between the other of the first and second shafts and the tubular member and allowing relative rotation of both of them (claim 6). In this case, the support mechanism can be realized with a simple configuration using a cylindrical member and a bearing. Further, since the bearing is provided between the first shaft and the second shaft, the relative rotation of the first and second shafts can be made smooth.

  Further, in the present invention, the transmission ratio variable that can change the transmission ratio (θ2 / θ1) as the ratio of the turning angle (θ2) of the steered wheels (4L, 4R) to the steering angle (θ1) of the steering member (2). The transmission ratio variable mechanism may be provided as a mechanism, and a steering member may be connected to the input member, and a turning mechanism (10) may be connected to the output member. In this case, the operation of the steering member by the driver can be corrected by the transmission ratio variable mechanism, for example, so-called active steering can be performed in which the counter steer operation is automatically performed by the transmission ratio variable mechanism.

In the present invention, a steering assist force applying mechanism (19) for applying a steering assist force may be provided (claim 8). In this case, the force required for the driver to steer can be reduced.
Note that, in the above, reference numerals 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.

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. And has a VGR (Variable Gear Ratio) function capable of changing the transmission ratio θ2 / θ1 as the ratio of the steered wheel turning angle θ2 to the steering angle θ1 of the steering member 2. ing.

  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 first axis A as the central axis of the first to third shafts 11 to 13 is also the rotational axis 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 other end of the second shaft 12 and one end of the third shaft 13 are connected via a torsion bar 14 so that they can be elastically rotated relative to each other and can transmit power.

The other end of the third shaft 14 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 an orbiting ring unit 39 interposed therebetween.

The input member 20 is connected to the steering member 2 and the first shaft 11 so as to be coaxial and rotatable together, and the output member 22 is connected to the second shaft 12 and coaxially rotatable. Has been. The first axis A is also the center axis and the rotation axis of the input member 20 and the output member 22.
The output member 22 is connected to the steered wheels 4L and 4R via the second shaft 12, the steered mechanism 10, and the like.

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. It constitutes a point contact bearing.
The rolling element 393 may be a cylindrical roller, a needle roller, or a tapered roller. Moreover, a single row or a double row may be sufficient. When double rows are used, the inner ring 391 can be prevented from falling. A double row angular bearing can be illustrated as a double row thing.

  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 B as a central axis inclined with respect to the first axis A. The inner ring 391 is rotatably supported by an outer ring 392 as a second raceway ring via a rolling element 393, so that the inner ring 391 can rotate around the second axis B and drives the outer ring 392. As the transmission ratio variable mechanism motor 23, which is an electric motor as an actuator for driving, is driven, it can rotate around the first axis A. The inner ring 391 and the outer ring 392 can perform Coriolis motion (swing motion) around the first axis A.

The transmission ratio variable mechanism motor 23 is disposed radially outward with the first axis A of the bearing ring unit 39 as the center. The transmission ratio variable mechanism motor 23 changes the transmission ratio θ2 / θ1 by changing the number of rotations of the outer ring 392 around the first axis A.
The transmission ratio variable mechanism motor 23 is, for example, a brushless motor that is coaxially disposed with the steering shaft 3, and includes a rotor 231 that holds the raceway ring unit 39, a housing 24 that surrounds the rotor 231 and that serves as a steering column. And a stator 232 fixed to the main body. The rotor 231 rotates around the first axis A.

  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 that detects torque transmitted between the second shaft 12 and the third shaft 13; a steering assist motor 25 as a steering assist actuator; a steering assist motor 25; A speed reduction mechanism 26 interposed between the shaft 13 and the shaft 13 is included.

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 a housing 24 and are accommodated 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 the amount of operation from the straight travel position of the steering member 2.

From the motor resolver 43, a signal regarding the rotation angle θr of the rotor 231 of the transmission ratio variable mechanism motor 23 is input.
From the torque sensor 44, a signal regarding the torque acting between the second and third shafts 12 and 13 is input as a value corresponding to the steering torque T acting on the steering member 2.
From the turning angle sensor 45, a signal regarding the rotation angle of the third shaft 13 is input as a value corresponding to the turning angle θ2.

A signal about the vehicle speed V is input from the vehicle speed sensor 46.
A signal regarding the yaw rate γ of the vehicle is input from the yaw rate sensor 47.
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 eighth bearings 31 to 38 are accommodated. Each of the first to fifth bearings 31 to 35 and the seventh to eighth bearings 37 to 38 is a rolling bearing such as an angular ball bearing, and the sixth bearing 36 is a rolling bearing such as a needle roller bearing. It is.

  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 second housing 52 accommodates a bus bar 99 described later of the transmission ratio variable mechanism motor 23 and a lock mechanism 58 for locking the rotor 231 of the transmission ratio variable mechanism motor 23. 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 61 is provided at the other end of the third housing 53. The end wall portion 61 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, input member 20, output member 22 and inner ring 391 of variable transmission ratio mechanism 5 each have an annular shape.

The input member 20 includes an input member main body 201 and a cylindrical member 202 that is disposed radially inward of the input member main body 201 and is connected to the input member main body 201 so as to be able to rotate together.
The first shaft 11 is connected to the tubular member 202 so as to be able to rotate along with the tubular member 202 by being inserted through the insertion hole 202 a of the tubular member 202.
The second shaft 12 is connected to the output member 22 so as to be able to rotate along with the output member 22 by passing through the insertion hole 22 a of the output member 22.

Opposing end portions 11 a and 12 a of the first shaft 11 and the second shaft 12 are supported coaxially and relatively rotatably by a support mechanism 133. The support mechanism 133 includes the cylindrical member 202 described above and the eighth bearing 38. That is, the cylindrical member 202 constitutes a part of the input member 20 and a part of the support mechanism 133.
The cylindrical member 202 surrounds the opposing end portions 11a and 12a of the first and second shafts 11 and 12, respectively. One end of the cylindrical member 202 faces the first bearing 31 in the radial direction. The other end of the cylindrical member 202 is opposed to the opposed end portion 12a of the second shaft 12 in the radial direction.

A bearing holding hole 109 is formed at the other end of the cylindrical member 202, and the opposed end portion 12 a of the second shaft 12 is inserted into the bearing holding hole 109. An eighth bearing 38 is interposed between the opposed end portion 12 a of the second shaft 12 and the bearing holding hole 109, and allows relative rotation between the cylindrical member 202 and the second shaft 12.
In addition, while connecting the cylindrical member 202 to the opposing end part 12a of the 2nd shaft 12 so that accompanying rotation is possible, the 8th bearing 38 is connected with the opposing end part 11a of the cylindrical member 202 and the 1st shaft 11. It may be interposed between them.

The inner ring 391 is disposed outward in the radial direction of the tubular member 202. The outer ring 392 is rotatably held in an inclined hole 63 formed in the inner peripheral portion 233 of the rotor 231 of the transmission ratio variable mechanism motor 23, and rotates around the first axis A with the rotor 231. To do. The inclined hole 63 has the second axis B as the central axis.
As the rotor 231 rotates around the first axis A, the race ring unit 39 performs Coriolis motion.

The outer ring 392 of the bearing ring unit 39 connects the input member 20 and the output member 22 so as to be differentially rotatable, and the inner ring 391 is connected so as to be rotatable together with the rotor 231 of the transmission ratio variable mechanism motor 23. May be. In this case, the race ring unit 39 is an inner ring support type.
FIG. 4 is a side view showing a part of the transmission ratio variable mechanism 5 in cross section. Referring to FIG. 3 and FIG. 4, the input member main body 201 and the inner ring 391 can transmit power because the input member main body 201 and the inner ring 391 are each provided with the first uneven engagement portion 64. ing. Further, the second ring engagement portion 67 is provided in each of the inner ring 391 and the output member 22, so that the inner ring 391 and the output member 22 can transmit power.

  The first uneven engagement portion 64 is formed on the first convex portion 65 formed on the power transmission surface 70 as one end surface of the input member main body 201 and the first end surface 71 as one end surface of the inner ring 391. And a first concave portion 66 that engages with the first convex portion 65. The power transmission surface 70 and the first end surface 71 are opposed to each other in the axial direction S of the steering shaft 3, and the first uneven engagement portion 64 can transmit power to the power transmission surface 70 and the first end surface 71. Engage with. The first recess 66 may be formed in an annular member formed separately from the inner ring main body, and the annular member may be held so as to be able to rotate along with the inner ring main body. In this case, an inner ring corresponding to the inner ring 391 is constituted by the inner ring main body and the annular member. Further, the arrangement of the first convex portion 65 and the arrangement of the first concave portion 66 may be interchanged.

  The second concavo-convex engaging portion 67 is formed on the second convex portion 68 formed on the power transmission surface 72 as one end surface of the output member 22 and the second end surface 73 as the other end surface of the inner ring 391. 2nd recessed part 69 engaged with the 2 convex part 68 is included. The power transmission surface 72 and the second end surface 73 are opposed to each other in the axial direction S of the steering shaft 3, and the second uneven engagement portion 67 can transmit power to the power transmission surface 72 and the second end surface 73. Engage with. The second recess 69 may be formed in an annular member formed separately from the inner ring main body, and the annular member may be held by the inner ring main body so as to be able to rotate together. In this case, an inner ring corresponding to the inner ring 391 is constituted by the inner ring main body and the annular member. Further, the arrangement of the second convex portion 68 and the arrangement of the second concave portion 69 may be interchanged.

FIG. 5 is a perspective view of the input member main body 201 and the inner ring 391. 4 and 5, the first convex portions 65 are formed at equal intervals over the entire circumference of the input member 20 in the circumferential direction C1. Similarly, the first recesses 66 are formed at equal intervals over the entire circumference of the inner ring 391 in the circumferential direction C2.
For example, 38 first protrusions 65 are formed. The number of first recesses 66 is different from the number of first protrusions 65. Depending on the difference between the number of first convex portions 65 and the number of first concave portions 66, differential rotation can be generated between the input member main body 201 and the inner ring 391.

Since the second axis B of the inner ring 391 is inclined at a predetermined angle θ with respect to the first axis A of the input member 20 and the output member 22, a part of the first convex portions 65 of the first Only the convex portion 65 and only a part of the first concave portions 66 of the first concave portions 66 mesh with each other.
FIG. 6 is a perspective view of main parts of the input member main body 201 and the inner ring 391. Referring to FIG. 6, each first convex portion 65 corresponds to a corresponding member of input member 20, inner ring 391, and output member 22, that is, a member provided with first convex portion 65. The input member main body 201 of the input member 20 is integrally formed using a single material.

  The first convex portion 65 and the input member main body 201 are molded together. Examples of methods for forming the first convex portion 65 and the input member main body 201 include forging, casting, sintering, injection molding, metal injection molding, and cutting. In the metal injection molding, metal powder is kneaded with a binder so that it can be injection-molded like plastic, and after injection-molding, the binder is removed by heating and sintered into a single metal.

  The first convex portion 65 extends over the entire power transmission surface 70 in the radial direction R1 of the input member 20, and has a semicircular cross section, for example. As the first convex portion 65 proceeds from the inside to the outside in the radial direction R1, the cross-sectional shape (semicircular shape) is increased. The first convex portion 65 has a semicircular shape centered on the center line E1 that is flush with the power transmission surface 70 at any position in the radial direction R1. With the above configuration, the width F1 of the first protrusion 65 in the circumferential direction C1 of the input member 20 as a corresponding member gradually increases from the inner side to the outer side in the radial direction R1, and the power transmission surface. The protrusion amount G1 from 70 is gradually increased.

  The base end portion 74 of the first convex portion 65 is provided with a relief portion 75 for avoiding contact with the corresponding first concave portion 66. The escape portions 75 are respectively formed at both ends of the first convex portion 65 in the circumferential direction C1, and are constituted by concave stripes that penetrate the input member main body 201 in the radial direction R1. By providing the relief portion 75, the first end surface 71 of the first recess 66 of the inner ring 391 can be prevented from coming into contact with the first protrusion 65, and the base end portion of the first protrusion 65 can be avoided. It is possible to prevent a close-down from occurring in the vicinity of 74.

Further, by providing the relief portion 75, it is possible to suppress wear of the mold portion around the relief portion 75 when the input member main body 201 is molded using a die.
FIG. 7 is a cross-sectional view showing the meshing between the first convex portion 65 and the first concave portion 66. With reference to FIGS. 6 and 7, the first convex portion 65 is configured such that the contact region 76 of the outer surface thereof is in contact with the contact region 79 of the corresponding first concave portion 66. . The contact region 76 is provided in a portion between the proximal end portion 74 and the distal end portion 77 of the first convex portion 65.

The contact area 76 is formed on both sides of the tip end portion 77. The position / width of the contact region 76 is determined based on the contact angle α of the first convex portion 65. The contact angle α of the contact region 76 of the first convex portion 65 is set within a range of 15 ° to 75 °, for example.
The contact region 76 is formed using a low friction material for reducing frictional resistance. The low friction material includes a material having a low friction coefficient as compared with the material of the first convex portion 65. Examples of the low friction material include diamond-like carbon (DLC), nitride obtained by nitriding the first convex portion 65, material obtained by performing a hard coat treatment, and a low μ coating material. .

Referring to FIG. 6, a lubricant holding portion 78 is formed in the vicinity of the contact region 76 in the input member main body 201. The lubricant retaining portion 78 retains a lubricant such as grease, and is formed on the power transmission surface 70 of the input member main body 201, for example.
The lubricant holding portion 78 is made of, for example, knurls, cross hatches, dimples, or the like formed on the power transmission surface 70, and the surface roughness of the power transmission surface 70 is roughened. The lubricant retaining portion 78 is formed, for example, by subjecting the power transmission surface 70 to press molding, texture processing, or shot peening processing.

The lubricant retaining portion 78 is formed on at least a part of the flat portion of the power transmission surface 70 where the first convex portion 65 is not formed. Note that the lubricant retaining portion 78 may be formed in a portion of the first convex portion 65 where the contact region 76 is not formed.
Each first recess 66 is made of a single material from the corresponding member of the input member 20, the inner ring 391 and the output member 22, that is, the inner ring 391 as a member provided with the first recess 66. It is formed integrally using.

The first recess 66 is formed in the same manner as the first protrusion 65 described above.
The first concave portion 66 has a shape that substantially matches the first convex portion 65. Specifically, the first recess 66 extends over the entire area of the first end surface 71 in the radial direction R2 of the inner ring 391, and has a semicircular cross section, for example. The first recess 66 has a larger cross-sectional shape (semicircular shape) as it proceeds from the inner side to the outer side in the radial direction R2. The first recess 66 has a semicircular shape centered on the center line E2 that is flush with the first end face 71 at any position in the radial direction R2. With the above configuration, the first recess 66 has a width F2 that gradually increases in the circumferential direction C2 of the inner ring 391 as a corresponding member in the radial direction R2 from the inner side to the outer side, and the first end surface. The amount of depression G2 from 71 is gradually increased.

  With reference to FIGS. 6 and 7, the first recessed portion 66 is configured such that the contact region 79 of the surface thereof is in contact with the contact region 76 of the corresponding first projecting portion 65. The contact region 79 is provided in a portion between the opening 80 and the bottom 81 of the first recess 66. This contact region 79 is formed on both sides of the bottom 81. The position / width of the contact region 79 is determined based on the contact angle α.

The contact region 79 is formed using a low friction material for reducing the frictional resistance. As this low friction material, the low friction material similar to the contact area 76 of the 1st convex part 65 can be illustrated.
Referring to FIG. 6, a lubricant holding portion 82 is formed in the vicinity of the contact region 79 in the inner ring 391. The lubricant retaining portion 82 retains a lubricant such as grease, and is formed on the first end surface 71 of the inner ring 391, for example.

The lubricant holding portion 82 has the same configuration as the lubricant holding portion 78 of the power transmission surface 70 of the input member main body 201. The lubricant holding portion 82 is formed on at least a part of the flat portion of the first end surface 71 where the first recess 66 is not formed. Note that the lubricant holding portion 82 may be formed in a portion of the first recess 66 where the contact region 79 is not formed.
Note that at least one of the lubricant holding portion 78 in the vicinity of the first convex portion 65 and the lubricant holding portion 82 in the vicinity of the first concave portion 66 may be eliminated. Further, at least one of the contact region 76 of the first convex portion 65 and the contact region 79 of the first concave portion 66 may be formed without using a low friction material.

Furthermore, as shown in FIG. 8, the first convex portion 65 </ b> A may have the same cross-sectional shape at any position in the radial direction R <b> 1 of the input member 20. At this time, the first recess 66A has the same cross-sectional shape at any position in the radial direction R2 of the inner ring 391.
Further, as shown in FIG. 9, the cross-sectional shape of the first recess 66B may be formed in a Gothic arc shape. In this case, the center lines E3 and E4 of the first arcuate surface 83 and the second arcuate surface 84 sandwiching the bottom 81B of the first recess 66B are offset from each other. With the above configuration, the contact region 76 of the first convex portion 65 and the contact region 79 of the first concave portion 66B can be brought into contact with each other more reliably.

  Referring to FIG. 4, a bevel gear is formed on each of the power transmission surface 70 of the input member main body 201 and the first end surface 71 of the inner ring 391 to form a first uneven engagement portion, and the inner ring 391. A bevel gear may be formed on each of the second end surface 73 and the power transmission surface 72 of the output member 22 to constitute the second concave-convex engaging portion. In this case, the first convex portion and the second convex portion are each configured by teeth of the bevel gear, and the first concave portion and the second concave portion are grooves between the teeth of the bevel gear, respectively. Consists of.

  4 and 6, the second convex portion 68 of the second concave-convex engaging portion 67 has the same configuration as the first convex portion 65 of the first concave-convex engaging portion 64. The second recess 69 has a configuration similar to that of the first recess 66. More specifically, the power transmission surface 72 of the output member 22 has the same configuration as the power transmission surface 70 of the input member main body 201, and the second end surface 73 of the inner ring 391 is the second end surface 73 of the inner ring 391. 1 has the same configuration as the end face 71 of the first. Therefore, the detailed description of the second uneven engagement portion 67 is omitted.

  Referring to FIG. 3 again, the rotor 231 of the transmission ratio variable mechanism motor 23 includes a cylindrical rotor core 85 extending in the axial direction S, and a permanent magnet 86 fixed to the outer peripheral surface of the rotor core 85. The transmission ratio variable mechanism 5 and the torque sensor 44 are accommodated inside the rotor core 85 in the radial direction. The rotor core 85 surrounds both the first concavo-convex engaging portion 64 and the second concavo-convex engaging portion 67 of the transmission ratio variable mechanism 5 over the entire circumference, and the torque sensor 44 over the entire circumference. Surrounded. By housing the transmission ratio variable mechanism 5 and the torque sensor 44 in the rotor core 85, the length of the housing 24 with respect to the axial direction S can be shortened. As a result, an impact absorbing stroke for absorbing the impact of the secondary collision of the vehicle. Can be secured for a long time. Further, it is possible to secure an arrangement space for a tilt / telescopic mechanism (not shown) provided adjacent to the housing 24.

Examples of the material of the rotor core 85 include steel materials, aluminum alloys, clad materials, and resin materials. When a clad material that is a composite material in which a plurality of kinds of metals are bonded together is used, resonance can be suppressed. When a resin material is used for at least a part of the rotor core 85, the rotor inertia can be reduced by reducing the weight.
A retained hole 87 is formed at one end of the rotor core 85. An annular bearing holding portion 88 is provided inside the held hole 87 in the radial direction. The bearing holding portion 88 is disposed on an annular convex portion 89 formed on the inner peripheral side of one end of the first housing 51. Since the second bearing 32 is interposed between the held hole 87 and the bearing holding portion 88, one end of the rotor core 85 is rotatably supported by the first housing 51.

  A held hole 90 is formed in an intermediate portion of the rotor core 85. An annular bearing holding portion 91 is provided inside the held hole 90 in the radial direction. The bearing holding portion 91 is disposed in an annular extending portion 92 formed on the inner peripheral side of one end of the second housing 52. The annular extending portion 92 has a cylindrical shape extending from the partition wall portion 93 provided at the other end of the second housing 52 to the one side S1 in the axial direction S, and the rotor core 85 is inserted therethrough.

  Since the fourth bearing 34 is interposed between the held hole 90 and the bearing holding portion 91, the intermediate portion of the rotor core 85 can rotate to the annular extending portion 92 of the second housing 52. It is supported. The rotor core 85 is supported at both ends by the second and fourth bearings 32 and 34 as a pair of bearings arranged with the bearing ring unit 39 sandwiched in the axial direction of the rotor 231.

The permanent magnet 86 of the rotor 231 has different magnetic poles alternately in the circumferential direction C3 of the steering shaft 3, and N poles and S poles are alternately arranged at equal intervals in the circumferential direction C3. The permanent magnet 86 is fixed to the outer peripheral surface of the intermediate portion of the rotor core 85. The positions of the permanent magnet 86 and a part of the transmission ratio variable mechanism 5 in the axial direction S are overlapped with each other.
The stator 232 of the transmission ratio variable mechanism motor 23 is accommodated in an annular first groove 94 formed at the other end of the first housing 51. The first groove 94 is open to the other side S2 in the axial direction S.

The stator 232 includes a stator core 95 formed by laminating a plurality of electromagnetic steel plates and an electromagnetic coil 96.
The stator core 232 includes an annular yoke 97 and a plurality of teeth 98 arranged at equal intervals in the circumferential direction of the yoke 97 and projecting radially inward of the yoke 97. The outer peripheral surface of the yoke 97 is fixed to the inner peripheral surface of the first groove-like portion 94 of the second housing 52 by shrink fitting or the like. An electromagnetic coil 96 is wound around each tooth 98.

  A bus bar 99 is arranged on the other side S <b> 2 in the axial direction S with respect to the stator 232. The bus bar 99 is accommodated in the second housing 52 in an annular shape as a whole, and is connected to each electromagnetic coil 96 of the transmission ratio variable mechanism motor 23. The bus bar 99 supplies power from the drive circuit to each electromagnetic coil 96. The positions of the bus bar 99 and the third and fourth bearings 33 and 34 with respect to the axial direction S are overlapped.

A lock mechanism 58 is disposed on the other side S <b> 2 in the axial direction S with respect to the bus bar 99. The lock mechanism 58 is for restricting the rotation of the rotor 231 of the transmission ratio variable mechanism motor 23 and is housed in one end of the second housing 52.
The lock mechanism 58 includes a regulated portion 100 coupled to the rotor core 85 so as to be able to rotate along with the rotor core 85 and a regulating portion 101 for regulating the rotation of the regulated portion 100 by engaging with the regulated portion 100. Yes. The regulated portion 100 is an annular member, and a recess 102 is formed on the outer peripheral surface. The recess 102 is formed at one or a plurality of locations in the circumferential direction of the regulated portion 100. The rotor core 85 may be provided with the recess 102. In this case, the rotor core 85 constitutes the restricted portion. A part of the regulated part 100 is overlapped with a part of the torque sensor 44 in the position in the axial direction S.

The restricting portion 101 is disposed opposite to the restricted portion 100 in the radial direction of the restricted portion 100. The restricting portion 101 is held by the second housing 52 and can be moved to the restricted portion 100 side. When the restricting portion 101 moves toward the restricted portion 100 and engages with the recess 102, the rotation of the rotor core 85 is restricted.
A motor resolver 43 is arranged on the other side S <b> 2 in the axial direction S with respect to the lock mechanism 58. The motor resolver 43 is accommodated in a second groove-shaped portion 103 formed at one end of the second housing 52, and is located radially outward of the rotor core 85.

The second groove portion 103 is an annular groove defined by an annular outer peripheral portion 104 at one end of the second housing 52 and an annular extending portion 92, and communicates with the first groove portion 94. ing. A housing space 139 for housing the transmission ratio variable mechanism motor 23, the lock mechanism 58, and the motor resolver 43 is defined by the first and second groove portions 94 and 103.
The motor resolver 43 and the torque sensor 44 are opposed to each other in the radial direction R3 of the steering shaft 3. A part of the motor resolver 43 and a part of the torque sensor 44 are overlapped with each other in the axial direction S. The motor resolver 43 includes a resolver rotor 105 and a resolver stator 106. The resolver rotor 105 is fixed to the outer peripheral surface 107 at the other end of the rotor core 85 so as to be able to rotate together. The resolver stator 106 is press-fitted and fixed to the inner peripheral surface 108 of the outer peripheral portion 104 of the second housing 52.

The first bearing 31 supports the input member 20 in a rotatable manner. The first shaft 11 is rotatably supported by the first housing 51 via the cylindrical member 202 of the input member 20 and the first bearing 31. The first bearing 31 is surrounded by the second bearing 32, and both positions are overlapped with respect to the axial direction S.
The third bearing 33 is interposed between the bearing holding hole 110 formed in the inner peripheral portion at the tip of the extending portion 92 of the second housing 52 and the bearing holding portion 111 formed in the output member 22. Yes. The output member 22 is rotatably supported by the annular extending portion 92 of the second housing 52 via the third bearing 33. The third bearing 33 is surrounded by the fourth bearing 34, and both positions are overlapped with each other in the axial direction S.

A preload is applied to each of the first concave and convex engaging portions 64 and the second concave and convex engaging portions 67, whereby the first convex portion 65 and the first concave portion 66 are smoothly engaged. And the smooth engagement with the 2nd convex part 68 and the 2nd recessed part 69 is each possible.
Specifically, a screw member 113 is disposed on the inner peripheral portion 112 at one end of the first housing 51. The screw member 113 constitutes a biasing member that biases the input member main body 201 in a biasing direction H (the other side S2 in the axial direction S) that brings the input member main body 201 closer to the output member 22. The screw member 113 constitutes a rigid member that rigidly supports the outer ring 312 of the first bearing 31 in the axial direction S. The screw member 113 urges the input member main body 201 toward the output member 22 to apply a preload to each of the first concavo-convex engaging portion 64 and the second concavo-convex engaging portion 67.

  A male screw portion 113 a formed on the outer peripheral surface of the screw member 113 is screwed into a female screw portion 134 a of a bearing holding hole 134 formed on the inner periphery of the annular convex portion 89 at one end of the first housing 51. Thereby, the screw member 113 urges (presses) one end surface of the outer ring 312 of the first bearing 31 held in the bearing holding hole 134 of the first housing 51 in the urging direction H. The outer ring 312 of the first bearing 31 is rotatable with respect to the bearing holding hole 134 and is relatively movable in the axial direction S. A lock nut 135 is provided adjacent to the screw member 113. The lock nut 135 restricts the rotation of the screw member 113 in a state where the lock nut 135 is screwed into the female screw portion 134a.

The inner ring 311 of the first bearing 31 is connected to the one end of the cylindrical member 202 so as to be able to rotate together with the end of the cylindrical member 202, and can be rotated together with the input member main body 201 via the cylindrical member 202. In addition, it is possible to move in the axial direction S. The inner ring 311 is in contact with one end portion of the input member main body 201 and presses the input member main body 201 in the urging direction H.
The first convex portion 65 of the first concave / convex engaging portion 64 faces the first concave portion 66 in the urging direction H. Similarly, the second concave portion 69 of the second concave-convex engaging portion 67 faces the second convex portion 68 in the urging direction H. An inner ring 331 of a third bearing 33 is press-fitted and fixed to the output member 22. The output member 22 has a central stepped portion in contact with one end surface of the inner ring 331 and presses the inner ring 331 in the urging direction H. The outer ring 332 of the third bearing 33 is received by an annular step 114 disposed adjacent to the bearing holding hole 110 that holds the outer ring 332 so as to be movable in the biasing direction H, and moves in the biasing direction H. Is regulated. The movement of the output member 22 in the biasing direction H is regulated by the third bearing 33.

  With the above configuration, the urging force of the screw member 113 is transmitted to the inner ring 311 via the outer ring 312 and the rolling element of the first bearing 31 and further transmitted to the input member main body 201. The urging force transmitted to the input member main body 201 is transmitted in the order of the first concavo-convex engaging portion 64 and the second concavo-convex engaging portion 67, and further transmitted to the inner ring 331, the rolling elements and the outer ring 332 of the third bearing 33. The urging force transmitted to the outer ring 332 of the third bearing 33 is received by the annular step portion 114.

As the inner ring 391 of the raceway ring unit 39 moves in the biasing direction H by the biasing force of the screw member 113, the rolling elements 393, the outer ring 392 of the raceway ring unit 39 and the rotor 231 of the transmission ratio variable mechanism motor 23 are It moves together in the urging direction H.
Specifically, the outer ring 392 of the track ring unit 39 is press-fitted and fixed in the inclined hole 63 of the rotor core 85. Thus, the rotor core 85 holds the outer ring 392 so as to be able to rotate along the first axis A and move along the axial direction S.

  Further, the outer rings 322 and 342 of the second bearing 32 and the fourth bearing 34 are loosely fitted in the corresponding annular held holes 87 and 90 of the rotor core 85, respectively, so that the rotor core 85 is relative to the axial direction S. Supports movable. The inner ring 321 of the second bearing 32 is press-fitted and fixed to the bearing holding portion 88 of the annular convex portion 89. The inner ring 341 of the fourth bearing 34 is press-fitted and fixed to the bearing holding portion 91 of the annular extending portion 92 of the second housing 52.

  Note that the screw member 113 may be used to bias the output member 22 in a biasing direction (a direction opposite to the biasing direction H) approaching the input member main body 201. In this case, the screw member 113 is screwed into the bearing holding hole 110 that holds the third bearing 33. The biasing force of the screw member 113 includes the third bearing 33, the output member 22, the second uneven engagement portion 67, the first uneven engagement portion 64, the input member main body 201, the inner ring 311 of the first bearing 31, It is transmitted in the order of the rolling element and the outer ring 312 and is received by the first housing 51.

  Further, the support mechanism 133 does not hinder the movement of the inner ring 391 in the urging direction H. Specifically, the outer ring 382 of the eighth bearing 38 of the support mechanism 133 is loosely fitted in the bearing holding hole 109 of the cylindrical member 202 and can be moved relative to the bearing holding hole 109 in the axial direction S. Has been. The inner ring 381 of the eighth bearing 38 is press-fitted and fixed to the opposed end portion 12 a of the second shaft 12. Alternatively, the outer ring 382 of the eighth bearing 38 may be press-fitted and fixed in the bearing holding hole 109, and the inner ring 381 may be loosely fitted to the facing end 12a.

The torque sensor 44 is disposed radially inward of the rotor core 85 of the transmission ratio variable mechanism motor 23, and includes a multipolar magnet 115 fixed to the intermediate portion of the second shaft 12, and the third shaft 13. It includes a pair of magnetic yokes 116 and 117 as soft magnetic bodies that are supported at one end and are arranged in a magnetic field generated by the multipolar magnet 115 to form a magnetic circuit.
The multipolar magnet 115 is a cylindrical permanent magnet, and a plurality of poles (the same number of N and S respectively) are magnetized at equal intervals in the circumferential direction.

The magnetic yokes 116 and 117 are opposed to the multipolar magnet 115 with a predetermined gap in the radial direction of the multipolar magnet 115, and surround the multipolar magnet 115. Each of the magnetic yokes 116 and 117 is molded on a synthetic resin member 118. The synthetic resin member 118 is coupled to one end of the third shaft 13 so as to be able to rotate together.
The torque sensor 44 further includes a pair of magnetism collecting rings 119 and 120 that guide magnetic flux from the magnetic yokes 116 and 117. The pair of magnetism collecting rings 119 and 120 are annular members formed using a soft magnetic material, surround the magnetic yokes 116 and 117, and are magnetically coupled to the magnetic yokes 116 and 117, respectively. .

The pair of magnetism collecting rings 119 and 120 are separated from each other in the axial direction S and face each other. The magnetism collecting rings 119 and 120 are molded by the synthetic resin member 121. The synthetic resin member 121 is held by the annular extending portion 92 of the second housing 52.
Magnetic flux is generated in the magnetic yokes 116 and 117 in accordance with the relative rotational amounts of the second and third shafts 12 and 13, and this magnetic flux is induced by the magnetic flux collecting rings 119 and 120, and the synthetic resin member 121. It is detected by a Hall IC (not shown) embedded in. Thereby, the magnetic flux density according to the torque applied to the second shaft 12 (steering member) can be detected.

  Referring to FIG. 2, a fifth bearing 35 is disposed on the other side S <b> 2 in the axial direction S with respect to the torque sensor 44. The fifth bearing 35 is interposed between a bearing holding portion 122 formed on the outer periphery of one end of the third shaft 13 and a bearing holding hole 123 formed in the partition wall portion 93 of the second housing 52. Yes. The bearing holding hole 123 rotatably supports one end of the third shaft 13 through the fifth bearing 35.

  The third shaft 13 surrounds the second shaft 12 and the torsion bar 14. Specifically, an insertion hole 124 opened at one end of the third shaft 13 is formed in the third shaft 13. The other end of the second shaft 12 is inserted through the insertion hole 124. An insertion hole 125 extending in the axial direction S is formed in the second shaft 12, and the torsion bar 14 is inserted through the insertion hole 125.

One end of the torsion bar 14 is connected to one end of the insertion hole 125 of the second shaft 12 so as to be able to rotate together by serration fitting or the like. The other end of the torsion bar 14 is connected to the insertion hole 124 of the third shaft 13 by serration fitting or the like so as to be able to rotate together.
A radially inner space of the annular extending portion 92 of the second housing 52 is a torque sensor housing chamber 126, and a structure for suppressing the intrusion of the lubricant into the torque sensor housing chamber 126 is further provided. It has been.

  Specifically, a third bearing 33 with a seal disposed at one end of the annular extending portion 92 of the second housing 52, an output member 22 disposed radially inward of the third bearing 33, One end of the torque sensor housing chamber 126 is closed by the second shaft 12 disposed radially inward of the output member 22. Further, torque is generated by the fifth bearing 35 with seal, the third shaft 13 disposed radially inward of the fifth bearing 35, and the torsion bar 14 that closes the insertion hole 124 of the third shaft 13. The other end of the sensor chamber 126 is closed.

With the above configuration, the lubricant filled in each of the first and second concave and convex engaging portions 64 and 67 can be prevented from entering the torque sensor housing chamber 126, and the worm shaft of the speed reduction mechanism 26 can be prevented. It is possible to suppress the lubricant filled in the meshing area of the worm wheel 28 and the worm wheel 28 from entering the torque sensor housing chamber 126.
The 2nd shaft 12 and the 3rd shaft 13 are mutually supported through the 6th bearing 36 so that relative rotation is possible. The sixth bearing 36 is surrounded by the worm wheel 28 of the speed reduction mechanism 26. The speed reduction mechanism 26 is accommodated in an accommodation chamber 128 defined by the outer peripheral portion 127 and the end wall portion 61 of the third housing 53 and the partition wall portion 93 of the second housing 52. A part of the worm wheel 28 and the sixth bearing 36 overlap with each other in the position in the axial direction S.

A seventh bearing 37 is interposed between the intermediate portion of the third shaft 13 and the end wall portion 61 of the third housing 53. The end wall portion 61 supports the third shaft 13 via the seventh bearing 37 so as to be rotatable.
The inner ring 371 of the seventh bearing 37 is sandwiched between an annular step 129 formed on the outer peripheral portion of the third shaft 13 and a nut member 130 screwed to the outer peripheral portion of the third shaft 13. Yes. The outer ring 372 of the seventh bearing 37 is sandwiched between an annular step 131 formed in the third housing 53 and a retaining ring 132 held by the third housing 53.

  Next, an example of the operation of the vehicle steering apparatus 1 will be described. In the following, (i) the rotation of the rotor 231 of the transmission ratio variable mechanism motor 23 is restricted, and (ii) the rotor 231 of the transmission ratio variable mechanism motor 23 is rotating, and the input member. The case where the rotation of the motor 20 is restricted and the case where (iii) the rotor 231 of the transmission ratio variable mechanism motor 23 is rotating and the input member 20 is rotating will be described.

In any of the cases (i), (ii), and (iii), the number of the first convex portions 65 of the first concave / convex engaging portion 64 is 38 and the number of the first concave portions 66 is 40, In the following description, it is assumed that the number of the second convex portions 68 of the second concave-convex engaging portion 67 is 40 and the number of the second concave portions 69 is 40.
In the case of the above (i), that is, when the rotation of the rotor 231 of the transmission ratio variable mechanism motor 23 is restricted by the lock mechanism 58, when the first shaft 11 is rotated by the operation of the steering member, the input member body 201 The first convex portion 65 rotates around the first axis A. At this time, the bearing ring unit 39 does not perform the Coriolis motion that rotates around the first axis A, and only the inner ring 391 rotates around the second axis B. By this rotation, the inner ring 391 provided with the first recess 66 is rotated, and the second shaft 12 is further rotated.

As a result, the inner ring 391 rotates 38/40 when the input member 20 rotates once. At this time, the output member 22 rotates 38/40. That is, the rotation of the input member 20 is decelerated to 19/20.
In the case of (ii) above, that is, when the rotor 231 of the transmission ratio variable mechanism motor 23 is rotating and the rotation of the input member 20 is restricted by the driver holding the steering member, As the rotor 231 rotates around the first axis A, the race ring unit 39 performs Coriolis motion. As a result, the inner ring 391 attempts to rotate the input member 20 and the output member 22 in the opposite directions. However, because the rotation of the input member 20 is restricted, only the output member 22 rotates.

  At this time, as a result of the number of the first concave portions 66 being increased by two as compared with the number of the first convex portions 65, when the outer ring 392 of the raceway ring unit 39 makes one rotation, the inner ring 391 The phase advances by an amount corresponding to the difference in the number of teeth (two). This is the rotation of the inner ring 391. As a result, when the outer ring 392 rotates once, the inner ring 391 rotates by an amount corresponding to the difference in the number of teeth, and the output member 22 rotates 2/40. As described above, the rotation of the rotor 231 of the transmission ratio variable mechanism motor 23 is reduced to 1/20 and output.

In the case of (iii) above, that is, when the input member 20 is rotated by rotating the rotor 231 of the transmission ratio variable mechanism motor 23 and steering the steering member by the driver, The rotation amount of the output member 22 is a value obtained by adding the rotation amount of the input member 20 (steering member) to the rotation amount of (ii) above.
Thus, when the vehicle is traveling at a relatively low speed, the function of assisting the driver's steering by amplifying the steering angle θ1 can be exhibited.

  When the vehicle is traveling at a relatively high speed, for example, the behavior of the vehicle is determined by comparing the steering angle θ1 with the yaw rate γ of the vehicle. As a result, when the vehicle behavior determined from the steering angle θ1 does not match the vehicle behavior determined from the detected yaw rate γ, the rotation of the rotor 231 of the transmission ratio variable mechanism motor 23 is increased. The vehicle's stability control (posture stability control) is performed by decelerating or decelerating. At this time, the drive of the rotor 231 of the transmission ratio variable mechanism motor 23 can be controlled so that the counter steering operation is performed.

As described above, according to the present embodiment, the first and second convex portions 65 and 68 of the first and second concave and convex engaging portions 64 and 67 and the first and second concave portions 66 and 69 are provided. Each of them is formed integrally with a corresponding member among the input member main body 201, the inner ring 391 and the output member 22 of the input member 20.
Thereby, the number of parts of the transmission ratio variable mechanism 5 can be reduced. Further, it is not necessary to separately prepare holding members for holding the first and second convex portions 65 and 68, respectively, and the number of parts of the transmission ratio variable mechanism 5 can be further reduced. Furthermore, since the number of parts is small, the assembly of the transmission ratio variable mechanism 5 can be facilitated.

Further, by forming the convex portions 65, 68 and the concave portions 66, 69 integrally with the corresponding members 201, 391, 22, the convex portions 65, 68 and the concave portions 66, 69 are Compared with the case where the corresponding members 201, 391, and 22 are formed separately, the accuracy of assembly between the components can be easily increased.
Further, the convex portions 65 and 68 and the concave portions 66 and 69 of the first and second concave and convex engaging portions 64 and 67 are integrated with the corresponding members 201, 391, and 22 using a single material. By forming, each convex part 65,68 (each recessed part 66,69) and the said corresponding member 201,391,22 can each be formed collectively, and a manufacturing process can be decreased.

Further, by providing the relief portion 75 at the base end portion 74 of each convex portion 65, 68, when each convex portion 65, 68 engages with the corresponding concave portion 66, 69, each first and second It is possible to prevent the convex portions 65 and 68 from being cut off, and to suppress wear of the convex portions 65 and 68 and the concave portions 66 and 69.
Further, among the convex portions 65 and 68 and the concave portions 66 and 69, the positions on the outer side in the radial direction of the corresponding members 201, 391, and 22, the circumferential width F 1 of the corresponding members 201, 391 and 22 are increased. F2 is widened, and as a result, slippage between the concave portions 66 and 69 and the corresponding convex portions 65 and 68 can be reduced. Thereby, each lifetime of each convex part 65,68 and each recessed part 66,69 can be made longer.

Lubricant holding portions 78 and 82 corresponding to the vicinity of the contact regions 76 and 79 of the convex portions 65 and 68 and the concave portions 66 and 69 are provided. Thereby, lubricant can be supplied to these contact areas 76 and 79 from the vicinity of each contact area 76 and 79, and engagement with each convex part 65 and 68 and the corresponding recessed parts 66 and 69 can be made smoother.
Furthermore, the contact regions 76 and 79 of the convex portions 65 and 68 and the concave portions 66 and 69 are formed using a low friction material for reducing frictional resistance. Thereby, the frictional resistance when the concave portions 66 and 69 and the corresponding convex portions 65 and 68 engage with each other can be further reduced.

Further, by providing the steering assisting force applying mechanism 19, it is possible to apply the steering assisting force to the steering mechanism 10, and to reduce the force required for the driver to steer.
Further, by providing the first and second concave and convex engaging portions 64 and 67 on the inner ring 391 side having a relatively small diameter among the inner ring 391 and the outer ring 392, the inner ring 391 is connected to the input member 20 and the output member 22. The span in the radial direction when supporting from both sides in the axial direction can be shortened. Thereby, the support rigidity of the inner ring 391 can be increased.

Further, of the inner ring 391 and the outer ring 392, the concave portions 66 and 69 of the first and second concave and convex engaging portions 64 and 67 are provided on the relatively small diameter inner ring 391 side. Thereby, the peripheral speed at the time of the drive of the recessed parts 66 and 69 provided in the inner ring | wheel 391 can be made small, and each engagement sound of the 1st and 2nd uneven | corrugated engaging parts 64 and 67 can be made small.
In addition, since the outer ring 392 of the raceway ring unit 39 is surrounded by the rotor 231, it is possible to suppress the meshing sounds of the first and second concave and convex engaging portions 64 and 67 from being transmitted to the outside of the rotor 231, and noise can be reduced. It can be further reduced.

Further, by holding the outer ring 392 in the inclined hole 63 of the rotor core 85 of the rotor 23, the second axis B as the central axis of the outer ring 392 can be inclined with respect to the first axis A.
Furthermore, the rotor core 85 can be supported at both ends by the second and fourth bearings 32 and 34, and the rigidity of the support of the rotor 231 can be increased. Further, since the inner ring 391 is disposed between the second and fourth bearings 32 and 34, the rotor core 85 that receives a force from the inner ring 391 can be firmly supported, and the runout of the rotor 231 can be prevented. . As a result, it can contribute to noise reduction.

  Further, the opposing ends 11a and 12a of the first and second shafts 11 and 12 are supported by the eighth bearing 38 so that the first and second shafts 11 and 12 are coaxial with each other. The degree can be improved. As a result, the input member 20 and the output member 22 can be prevented from wobbling with respect to each other, and the engagement state between the convex portions 65 and 68 and the corresponding concave portions 66 and 69 in the concave and convex engaging portions 64 and 67 is inadvertent. Can be suppressed, and an increase in engagement sound can be prevented.

Further, the support mechanism 133 can be realized by a simple configuration using the cylindrical member 202 and the eighth bearing 38. Furthermore, since the eighth bearing 38 is provided between the first shaft 11 and the second shaft 12, the relative rotation of the first and second shafts 11 and 12 can be made smooth. .
Further, the operation of the steering member 2 by the driver can be corrected by the transmission ratio variable mechanism 5, for example, so-called active steering is possible in which the counter steer operation is automatically performed by the transmission ratio variable mechanism 5.

  Further, in each of the first concavo-convex engaging portion 64 provided on the first end surface 71 side of the inner ring 391 and the second concavo-convex engaging portion 67 provided on the second end surface 73 side of the inner ring 391, A preload is applied between each of the convex portions 65, 68 and the corresponding concave portion 66, 69. Thereby, in each of the first and second concave and convex engaging portions 64 and 67, it is possible to prevent rattling between the convex portions 65 and 68 and the corresponding concave portions 66 and 69. Can be reduced.

  Further, since the inner ring 391 has a smaller diameter than the outer ring 392, the radial support span when the inner ring 391 is supported by the input member 20 and the output member 22 from both sides in the axial direction can be shortened, and the urging force from the screw member 113 can be reduced. The bending of the inner ring 391 due to the above can be reduced. Thereby, a sufficient urging force can be applied to each of the concave portions 66 and 69 formed in the inner ring 391, and rattling occurs in each of the first and second concave and convex engaging portions 64 and 67. It can be prevented more reliably.

Further, since the screw member 113 urges the input member 20 toward the output member 22, the urging force of the screw member 113 is applied to the input member 20 and the first end surface 71 side of the inner ring 391. 1 concavo-convex engaging portion 64, the second concavo-convex engaging portion 67 provided on the second end face 73 side of the inner ring 391, and the output member 22 can be transmitted in this order.
Furthermore, the preload can be applied to the first bearing 31 by the screw member 113, and the generation of abnormal noise caused by the first bearing 31 can be prevented.

Further, the biasing force by the screw member 113 can be adjusted by adjusting the screwing amount of the screw member 113 into the female screw part 134a.
Furthermore, the urging force of the screw member 113 can be transmitted to the inner ring 311 of the first bearing 31 via the outer ring 312 of the first bearing 31, and a preload can be reliably applied to the first bearing 31. .

Further, the force that the output member 22 tends to move in the urging direction H can be received by the third bearing 33, and a preload can be applied to the third bearing 33.
The second and fourth bearings 32 and 34 support the rotor 231 so as to be movable in the axial direction S. As a result, the outer ring 392 and the rotor 231 can be moved in the axial direction of the rotor 231 as the inner ring 391 moves in the axial direction of the rotor 231 by the urging force of the screw member 113. As a result, the inner ring 391 An unnecessary force can be prevented from acting between the outer ring 392 and the outer ring 392.

  Further, the output of the transmission ratio variable mechanism 5 is transmitted to the steering mechanism 10 via the steering assist force applying mechanism 19. Thus, when the output of the steering assist force applying mechanism 19 is transmitted to the steering mechanism 10, this output can be transmitted to the steering mechanism 10 without going through the transmission ratio variable mechanism 5. Thereby, since the power input to the transmission ratio variable mechanism 5 can be reduced, the transmission ratio variable mechanism 5 can be reduced in size.

Further, by arranging the input member 20, the inner ring 391 and the output member 22 side by side in the direction in which the first axis A extends (axial direction S), the transmission ratio variable mechanism 5 can be connected to the input member 20 and the output member 22. The radial direction (radial direction R3) can be reduced in size, and as a result, the transmission ratio variable mechanism 5 can be further reduced in size.
Further, the rotor core 85 of the rotor 231 of the transmission ratio variable mechanism motor 23 has a cylindrical shape surrounding the first and second concave and convex engaging portions 64 and 67. Thereby, the rotor 231 and the first and second concave and convex engaging portions 64 and 67 can be arranged at positions overlapping with each other in the axial direction S, and further downsizing of the vehicle steering apparatus 1 can be achieved. In addition, the rotor 231 can be used as a soundproof wall, and the meshing sound of the first and second concave and convex engaging portions 64 and 67 can be prevented from leaking to the outside.

Furthermore, since the torque sensor 44 is surrounded by the rotor core 85 of the rotor 231 of the transmission ratio variable mechanism motor 23, the rotor 231 and the torque sensor 44 can be arranged at an overlapping position with respect to the axial direction S. Further downsizing can be achieved.
Further, the transmission ratio variable mechanism 5 and the steering assist force applying mechanism 19 are provided in a housing 24 as a steering column. By assembling the housing 24 to the vehicle body, the transmission ratio variable mechanism 5 and the steering assist force applying mechanism 19 can be assembled together to the vehicle body. Further, because of the excellent quietness, even if the transmission ratio variable mechanism 5 and the steering assist force applying mechanism 19 are provided in the vehicle compartment in which the housing 24 is disposed, the influence of these driving sounds is small.

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 steering assist force applying mechanism 19 shown in FIG. 1 may be eliminated. In the following, differences from the above-described embodiment will be mainly described, and the same components are denoted by the same reference numerals and description thereof is omitted.

In this case, the drive circuit 41, the steering assist motor 25, the speed reduction mechanism 26, the third shaft 13, the torsion bar 14, and the torque sensor 44 shown in FIG. The other end of the second shaft 12 is connected to the universal joint 9.
In this case, as shown in FIG. 10, the end wall portion 61C of the third housing 53C is fixed to the second housing 52C in a state along the other end of the second housing 52C. The third housing 53C is not provided with a storage chamber for storing the speed reduction mechanism.

The second shaft 12C extends to the other end of the third housing 53C, protrudes to the outside of the housing 24C, and is connected to a steering mechanism (not shown). An inner ring 371 of a seventh bearing 37 is coupled to the middle portion of the second shaft 12C so as to be able to rotate together.
As shown in FIG. 11, instead of the input member 20, an input member 20D in which an input member main body 201D and a cylindrical member 202D are integrally formed using a single member may be used. The 1st convex part 65 of the 1st uneven | corrugated engaging part 64 is integrally formed using the input member 20D as a corresponding member using a single member.

The cylindrical member 202D and the output member 22D of the input member 20D include opposing surfaces 136 and 137 that face each other. These opposed surfaces 136 and 137 are opposed to each other with a gap 138 provided in an axial direction S as a direction parallel to the first axis A.
Thereby, when the input member 20D and the output member 22D approach each other due to the urging force of the screw member 113, it is possible to prevent the opposing surfaces 136 and 137 from contacting each other.

In addition, since the input member 20D and the first convex portion 65 are integrally formed of a single member, the first convex portion 65 and the input member 20D can be formed in a lump, and manufacturing. The number of processes can be reduced.
Further, the present invention can be applied to other general devices other than the vehicle steering device.

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 the side view which represented a part of transmission ratio variable mechanism with the cross section. It is a perspective view of an input member main body and an inner ring. It is a perspective view of the principal part of an input member main body and an inner ring. It is sectional drawing which shows meshing | engagement with a 1st convex part and a 1st recessed part. It is a perspective view of the principal part of another embodiment of this invention. It is sectional drawing of the principal part of another embodiment of this invention. It is sectional drawing of the principal part of another embodiment of this invention. It is sectional drawing of the principal part of another embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle steering device, 2 ... Steering member, 4L, 4R ... Steering wheel, 5 ... Transmission ratio variable mechanism, 10 ... Steering mechanism, 11 ... 1st shaft (1st axis), 11a ... (1st Opposite end of 12), second shaft (second axis), 12a ... opposite end of second axis, 19 ... steering assist force applying mechanism, 20 ... input member, 22 ... output Member, 22a ... (output member) insertion hole, 23 ... transmission ratio variable mechanism motor (actuator, electric motor), 24, 24C ... housing, 32 ... second bearing (one of a pair of bearings), 34 ... first 4 bearings (the other of the pair of bearings), 38... (Eighth bearing), 63... Inclined holes, 64... First concave and convex engaging portions, 65 and 65 A. 66A, 66B... First recess, 67... Second concavo-convex engagement portion, 68... Second projection, 69. Power transmission surface (of the input member) 71 ... first end surface, 72 ... power transmission surface of the output member, 73 ... second end surface, 133 ... support mechanism, 202, 202D ... cylindrical member, 202a ... ( Insertion hole) 231... Rotor, 391. Inner ring, 392. Outer ring, 393. Rolling element, A... First axis, B... Second axis, .theta.1 ... Steering angle, .theta.2 ... Steering angle, .theta.2 / Θ1... Transmission ratio.

Claims (8)

An input member and an output member that are rotatable about a first axis;
An inner ring having first and second end faces and connecting 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 capable of rotationally driving the outer ring,
The second axis as the central axis of the inner ring and the outer ring is inclined with respect to the first axis,
Each of the input member and the output member has 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 provided on the other side and engaged with the convex portion. Variable mechanism. In Claim 1, the actuator includes an electric motor,
This electric motor is a transmission ratio variable mechanism having a rotor that holds the outer ring so as to be able to rotate along with the rotor and can rotate around a first axis.   The transmission ratio variable mechanism according to claim 2, wherein the rotor has an inclined hole that has a central axis along a second axis and holds the outer ring. In Claim 2 or 3, the rotor is supported by a pair of bearings held by a housing,
A transmission ratio variable mechanism in which the inner ring is arranged between the pair of bearings with respect to the axial direction of the rotor. In any one of Claims 1-4, The 1st axis | shaft which continues through the insertion hole formed in the input member so that rotation with the input member is possible,
A second shaft that is inserted through an insertion hole formed in the output member and is connected to the output member so as to be able to rotate along with the output member;
A transmission ratio variable mechanism comprising: a support mechanism that coaxially supports opposite ends of the first and second shafts so as to be relatively rotatable. The cylindrical support member according to claim 5, wherein the support mechanism surrounds the opposing ends of the first and second shafts and is coupled to one of the first shaft and the second shaft so as to be able to rotate together.
A transmission ratio variable mechanism including a bearing interposed between the other of the first and second shafts and the cylindrical member and allowing relative rotation between the two. The transmission ratio variable mechanism according to any one of claims 1 to 6 is provided as a transmission ratio variable mechanism capable of changing a transmission ratio as a ratio of a turning angle of a steered wheel to a steering angle of a steering member,
A vehicle steering apparatus in which a steering member is connected to the input member and a steering mechanism is connected to the output member.   The vehicle steering apparatus according to claim 7, further comprising a steering assist force applying mechanism that applies a steering assist force.

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