JP5333846B2 - Oscillating gear device, transmission ratio variable mechanism, and vehicle steering device - Google Patents

Description

  The present invention relates to an oscillating gear device that transmits rotation, a transmission ratio variable mechanism including the oscillating gear device, and a vehicle steering device.

  For example, in Patent Document 1, in a gear that has teeth on the periphery and transmits load, each tooth formed of a highly rigid material divides the tooth thickness by 2 in the entire tooth trace direction, and the radius of the gear from the tooth tip. Gears having slits recessed in the direction have been proposed.

JP-A-9-317852

In Patent Document 1, in order to reduce vibration and noise due to the meshing of gears, a slit having a depth similar to the tooth height is provided. However, the slit having such a depth has a problem that the strength of the teeth is lowered.
The present invention has been made based on such a background, and an object thereof is to provide an oscillating gear device having high strength and low noise.

  Another object of the present invention is a small oscillating gear device with low noise, a small and low noise transmission ratio variable mechanism with an oscillating gear device, and a small oscillating gear device with an oscillating gear device. The present invention provides a vehicle steering apparatus with low noise.

In order to achieve the above object, the present invention provides an input member (22, 322, 522) and an output member (rotating around the first axis), each having a central axis on the first axis (A1). 23) and intermediate members (39a, 339a) connecting the input member and the output member so as to allow differential rotation of the input member and the output member, wherein the intermediate member is the first member. A plurality of intermediate members having a central axis on a second axis (B1) inclined with respect to the axis of the first axis and rotatable about the second axis, wherein the intermediate member is arranged in an arc shape on the input member A plurality of second concave portions (54, 354) or second convex portions (55, 355) that can be engaged with the first convex portions (52, 552) or the first concave portion (65), and a circle on the output member fourth convex portions of the plurality arranged in an arc (60) or 4 recesses engageable with the plurality of third recesses (57) or the third convex portions (58) are arranged in a circular arc shape, the length of the second recess or a second protrusion in the radial direction of the intermediate member The length of the third concave portion or the third convex portion with respect to the radial direction of the intermediate member is smaller than the length of the first convex portion or the first concave portion with respect to the radial direction of the input member. The intermediate member (39a, 339a) is smaller than the length of the fourth convex portion or the fourth concave portion with respect to the radial direction, and the axial direction (X1) of the member from the bottom (54a, 354a) of the concave portion of the member. A swinging gear device (20, 320) characterized in that slits (61, 361) having a predetermined depth (D1) extending along the slit are formed (claim 1).

According to the present invention, power is transmitted between a member provided with a recess with a slit ( intermediate member) and a counterpart member (an input member, an output member) having a protrusion engaged with the recess of the member. Sometimes, the portion defining the concave portion with the slit can be bent to increase the meshing rate and the contact area between the member provided with the concave portion with the slit and the counterpart member. Thereby, the stress added to the member provided with the recessed part with a slit at the time of power transmission can be disperse | distributed. Therefore, even if the pitch circle diameter (PCD) of the concave portion and the convex portion is reduced, the strength of the member provided with the concave portion with the slit can be ensured. Therefore, the pitch circle diameter (PCD) of the concave and convex portions can be made as small as possible, and the noise can be reduced through a decrease in the peripheral speed of the concave and convex portions. Furthermore, the increase in the contact area can further contribute to noise reduction. Moreover, since the slit is formed so as to extend from the bottom of the concave portion, the strength of the oscillating gear device can be improved without reducing the strength of the portion defining the concave portion with the slit.

In order to achieve the above object, the present invention provides an input member (22, 422, 522) and an output, each having a central axis on the first axis (A1) and rotatable about the first axis. A member (23) and intermediate members (239a, 439a) for connecting the input member and the output member so as to allow differential rotation of the input member and the output member. A center axis is provided on the second axis (B1) inclined with respect to the first axis, and is rotatable around the second axis. The intermediate member is arranged in an arc shape on the input member. A plurality of second concave portions (254, 354) or second convex portions (255, 455) that can be engaged with the plurality of first convex portions (52, 552) or the first concave portion (66), and the output member. a plurality of fourth protruding portions arranged arcuately ( 0) or a fourth recess engageable with a plurality of third recesses (57) or the third convex portions (58) are arranged in an arc, the intermediate said second recess in the radial direction of the member or the second The length of the convex portion is smaller than the length of the first convex portion or the first concave portion with respect to the radial direction of the input member, and the length of the third concave portion or the third convex portion with respect to the radial direction of the intermediate member is The intermediate member (239a, 439a) is smaller than the length of the fourth convex portion or the fourth concave portion with respect to the radial direction of the output member, and the axis of the member from the top portion (255a, 455a) of the convex portion of the member. A slit (261, 461) having a predetermined depth (D2) extending along the direction (X1) is formed, and the predetermined depth is larger than the height value (H2) of the convex portion of the member. Oscillating gear device (220, 420) Is (claim 2).

According to the present invention, power is transmitted between a member ( intermediate member) provided with a convex portion with a slit and a counterpart member ( input member, output member) having a concave portion engaged with the convex portion of the member. When doing so, the convex part with a slit can be bent, and the meshing rate and contact area between the member in which the convex part with a slit was provided and the other party member can be increased. Thereby, the stress added to the member provided with the convex part with a slit at the time of power transmission can be disperse | distributed. Therefore, even if the pitch circle diameter (PCD) of the concave portion and the convex portion is reduced, the strength of the member provided with the convex portion with the slit can be ensured. Therefore, the pitch circle diameter (PCD) of the concave and convex portions can be made as small as possible, and the noise can be reduced through a decrease in the peripheral speed of the concave and convex portions. Furthermore, the increase in the contact area can further contribute to noise reduction. In addition, since the depth of the slit is greater than the height of the convex portion with the slit, the convex portion with the slit is more easily bent than when the depth of the slit is equal to the height of the convex portion with the slit. In addition, the thickness of the base portion of the convex portion with the slit can be increased. As a result, the strength of the convex portion with the slit can be improved, and consequently the strength of the oscillating gear device can be improved.

  In order to achieve the above object, the present invention includes the oscillating gear device and the electric motor (21) for driving the intermediate member, and the rotation angle of the output member with respect to the rotation angle of the input member. This is a transmission ratio variable mechanism (5) capable of changing the ratio. According to the present invention, when the rotation is transmitted from the input member to the output member, the ratio of the rotation angle of the output member to the rotation angle of the input member can be changed by driving the intermediate member by the electric motor. Further, as described above, the strength of the oscillating gear device can be improved, so that the oscillating gear device can be maintained while maintaining the magnitude of the torque that can be transmitted by the oscillating gear device above a certain value. It can be downsized. Thereby, a transmission ratio variable mechanism can be reduced in size. Therefore, it is possible to provide a transmission ratio variable mechanism that is small and has low noise.

  Further, the present invention for achieving the above object is a transmission which is a ratio of the turning angle (θ2) of the wheels (4L, 4R) to the steering angle (θ1) of the steering member (2) using a transmission ratio variable mechanism. A vehicle steering apparatus capable of changing a ratio, wherein the input member is connected to the steering member, and the output member is connected to a wheel side member (12). Item 4). According to this invention, it is possible to change the transmission ratio, which is the ratio of the wheel turning angle to the steering angle of the steering member. Further, as described above, the strength of the oscillating gear device can be improved. It can be downsized. Thereby, a vehicle steering device can be reduced in size. Therefore, a small and low-noise vehicle steering apparatus can be provided.

  In the above description, the alphanumeric characters 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 an electric power steering device concerning a 1st embodiment of the present invention. It is a fragmentary sectional view of an oscillating gear device. It is a side view of the principal part of the rocking | fluctuation type gear apparatus which shows the engaging part of an input member and an inner ring | wheel. It is a side view of the principal part of the rocking | fluctuation type gear apparatus which shows the engaging part of the input member and inner ring which concern on 2nd Embodiment of this invention. It is a side view of the principal part of the rocking | fluctuation type gear apparatus which concerns on 3rd Embodiment of this invention. It is a side view of the principal part of the rocking | fluctuation type gear apparatus which concerns on 4th Embodiment of this invention. It is a perspective view of the principal part of the rocking | fluctuation type gear apparatus which concerns on 5th Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering apparatus 1 according to a first embodiment of the present invention.
Referring to FIG. 1, an electric power steering apparatus 1 which is an example of a vehicle steering apparatus uses a steering torque applied to a steering member 2 such as a steering wheel via a steering shaft 3 as a steering shaft. It is given to the wheels 4L and 4R for turning. The electric power steering apparatus 1 has a VGR (Variable Gear Ratio) function capable of changing a transmission ratio θ2 / θ1 as a ratio of the steering angle θ2 of the wheels 4L, 4R to the steering angle θ1 of the steering member 2. Yes.

  In addition, the electric power 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 arranged coaxially. The first axis A1 passing through the central axis of the first to third shafts 11 to 13 is also the rotation axis of the first to third shafts 11 to 13. Hereinafter, the axial direction S1 of the steering shaft 3 is simply referred to as the axial direction S1, the radial direction R1 of the steering shaft 3 is simply referred to as the radial direction R1, and the circumferential direction C1 of the steering shaft 3 is simply referred to as the circumferential direction C1.

  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 portion of the first shaft 11 and the one end portion of the second shaft 12 are coupled so as to be differentially rotatable through a transmission ratio variable mechanism 5 as a differential mechanism. Further, 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 transmit power. The other end of the third shaft 13 is connected to the wheels 4L and 4R through 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. A knuckle arm 18L is connected to one end of the rack shaft 16 via a tie rod 17L. A knuckle arm 18R is coupled to the other end of the rack shaft 16 via a tie rod 17R.

  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, whereby the knuckle arms 18L and 18R rotate. Thereby, the wheels 4L and 4R respectively connected to the knuckle arms 18L and 18R are 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. The transmission ratio variable mechanism 5 includes an oscillating gear device 20 and a transmission ratio variable mechanism motor 21 as an electric motor. The oscillating gear device 20 includes an input member 22 connected to the other end of the first shaft 11, an output member 23 connected to one end of the second shaft 12, and the input member 22 and the output. And a bearing ring unit 39 interposed between the members 23. In this embodiment, the second shaft 12 corresponds to a wheel side member.

  The input member 22 is connected to the first shaft 11 so as to be coaxial and rotatable. The output member 23 is connected to the second shaft 12 so as to be coaxial and rotatable. The input member 22 and the output member 23 are arranged along the first axis A1. The first axis A1 is also the center axis and the rotation axis of the input member 22 and the output member 23.

  Further, the bearing ring unit 39 has a second axis B1 as a central axis inclined with respect to the first axis A1, and an inner ring 39a as a first bearing ring and a second bearing ring. Outer ring 39b and rolling elements 39c such as balls interposed between the inner ring 39a and the outer ring 39b. The inner ring 39 a connects the input member 22 and the output member 23 so as to allow differential rotation of the input member 22 and the output member 23. The inner ring 39a is engaged with each of the input member 22 and the output member 23 so as to be able to transmit rotation. The inner ring 39a is rotatably supported by the outer ring 39b via rolling elements 39c. The inner ring 39a can rotate around the second axis B1. Further, the inner ring 39a rotates around the first axis A1 when the transmission ratio variable mechanism motor 21 which is an actuator for driving the outer ring 39b is driven. The inner ring 39a and the outer ring 39b are capable of Coriolis motion (swing motion) around the first axis A1.

  The transmission ratio variable mechanism motor 21 is a brushless motor, for example, and is arranged coaxially with the first and second shafts 11 and 12. The first axis A1 is also the central axis of the transmission ratio variable mechanism motor 21. The transmission ratio variable mechanism motor 21 changes the transmission ratio θ2 / θ1 by changing the number of revolutions of the outer ring 39b around the first axis A1. The transmission ratio variable mechanism motor 21 includes a cylindrical rotor 21 a that holds the raceway ring unit 39, and a stator 21 b that surrounds the rotor 21 a and is fixed to the housing 24.

  The electric power steering apparatus 1 also 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 23 of the variable transmission ratio mechanism 5, the third shaft 13 as an output shaft continuous with the steering mechanism 10, A torque sensor 44 for detecting torque transmitted to the second shaft 12, a steering assist motor 25, and a speed reduction mechanism 26 interposed between the motor 25 and the third shaft 13. The speed reduction mechanism 26 is, for example, a worm gear mechanism, and a worm shaft 27 as a drive gear connected to the output shaft 25 a of the motor 25, and a driven gear that meshes with the worm shaft 27 and is connected to the third shaft 13 so as to be able to rotate together. And a worm wheel 28 as a gear. The output of the motor 25 is transmitted to the third shaft 13 via the speed reduction mechanism 26.

  Driving of the transmission ratio variable mechanism motor 21 and the 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 21 via the drive circuit 40 and is connected to the 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 sensor that detects the rotation angle of the rotor 21a of the transmission ratio variable mechanism motor 21, a torque sensor 44, a turning angle sensor 45, and 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 operation amount from the straight traveling position of the steering member 2. Further, a signal regarding the rotation angle θr of the rotor 21 a of the transmission ratio variable mechanism motor 21 is input from the motor resolver 43 to the control unit 29. In addition, a signal regarding the torque acting on the second shaft 12 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. Further, 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. Further, 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 21 and the motor 25 based on the signals of the sensors 42 to 47 and the like.

  With the above configuration, the torque from the steering member 2 and the torque from the transmission ratio variable mechanism 5 are transmitted to the steering mechanism 10 via the steering assist force applying mechanism 19. Specifically, the steering torque input to the steering member 2 is input to the input member 22 of the transmission ratio variable mechanism 5 via the first shaft 11 and input from the input member 22 to the inner ring 39a. In addition to torque from the steering member 2, torque from the transmission ratio variable mechanism motor 21 transmitted to the inner ring 39 a through the outer ring 39 b and the rolling elements 39 c is transmitted to the inner ring 39 a, and these torques are output to the output member 23. Is transmitted to. The torque transmitted to the output member 23 is transmitted to the second shaft 12. Further, the torque transmitted to the second shaft 12 is transmitted to the torsion bar 14 and the third shaft 13, and is combined with the output from the motor 25 via the universal joint 7, the intermediate shaft 8, and the universal joint 9. Is transmitted to the steering mechanism 10.

  As described above, the electric power steering apparatus 1 is formed with the power transmission path D that transmits torque from the steering member 2 to the steering mechanism 10. The power transmission path D includes the first shaft 11, the input member 22, the inner ring 39a, the output member 23, the second shaft 12, the torsion bar 14 and the third shaft 13, the universal joint 7, the intermediate shaft 8, and the universal joint. 9 is a route through 9.

FIG. 2 is a partial cross-sectional view of the oscillating gear device 20.
Referring to FIG. 2, the oscillating gear device 20 has a central axis on a first axis A1 and an input member 22 and an output member 23 that are rotatable around the first axis A1, and an input. And an inner ring 39a as an intermediate member connecting the input member 22 and the output member 23 so as to allow differential rotation of the member 22 and the output member 23. The input member 22, the output member 23, and the inner ring 39a are each formed of a material containing iron. The input member 22, the output member 23, and the inner ring 39a each have elasticity. The input member 22 is formed in a cylindrical shape. The first shaft 11 is fitted to the inner periphery of the input member 22 so as to be able to rotate together. The output member 23 is formed in a cylindrical shape. The second shaft 12 is fitted to the inner periphery of the output member 23 so as to be able to rotate together. The input member 22 and the output member 23 are opposed to each other with an interval in the axial direction S1. The inner ring 39 a is disposed between the input member 22 and the output member 23 so as to be inclined with respect to the input member 22 and the output member 23. The inner ring 39a has a central axis on a second axis B1 inclined with respect to the first axis A1, and is rotatable about the second axis B1.

  In addition, a plurality of first protrusions 52 arranged in an arc shape at equal intervals in the circumferential direction of the input member 22 are formed on the first end surface 51 of the input member 22 facing the inner ring 39a. The second end surface 53 of the inner ring 39a that faces the input member 22 is formed with a plurality of second recesses 54 that are arranged in an arc shape at equal intervals in the circumferential direction Z1 of the inner ring 39a. The number of second recesses 54 is greater than the number of first projections 52. In addition, each second recess 54 is formed in a shape with which the first projection 52 can be engaged. Of the plurality of second recesses 54, some of the second recesses 54 are engaged with the first protrusions 52 that face in the axial direction S <b> 1. Moreover, the 2nd convex part 55 is formed between the 2nd recessed parts 54 adjacent to the circumferential direction Z1 of the inner ring | wheel 39a, respectively.

  Each first convex portion 52 extends in the radial direction of the input member 22, and the cross section of each first convex portion 52 cut along the circumferential direction of the input member 22 is, for example, a semicircle that is convex in the axial direction S1. It is formed in a shape. Each second recess 54 extends in the radial direction Y1 of the inner ring 39a, and the cross section of each second recess 54 cut along the circumferential direction Z1 of the inner ring 39a is, for example, recessed in the axial direction X1 of the inner ring 39a. It is formed in a semicircular shape. The length of the second concave portion 54 in the radial direction Y1 of the inner ring 39a is smaller than the length of the first convex portion 52 in the radial direction of the input member 22. That is, the strength of the second concave portion 54 is lower than the strength of the first convex portion 52.

  On the other hand, the third end surface 56 of the inner ring 39a facing the output member 23 is formed with a plurality of third recesses 57 arranged in an arc shape at equal intervals in the circumferential direction Z1 of the inner ring 39a. A third convex portion 58 is formed between the third concave portions 57 adjacent to each other in the circumferential direction Z1 of the inner ring 39a. In addition, a plurality of fourth convex portions 60 arranged in an arc shape at equal intervals in the circumferential direction of the output member 23 are formed on the fourth end surface 59 of the output member 23 facing the inner ring 39a. The number of fourth convex portions 60 is larger than the number of third concave portions 57. Each third recess 57 is formed in a shape that allows the fourth protrusion 60 to be engaged. A fourth convex portion 60 facing the axial direction S1 is engaged with some of the third concave portions 57 among the plurality of third concave portions 57.

  Each third recess 57 extends in the radial direction Y1 of the inner ring 39a, and the cross section of each third recess 57 cut along the circumferential direction Z1 of the inner ring 39a is, for example, a half that is recessed in the axial direction X1 of the inner ring 39a. It is formed in a circular shape. Moreover, each 4th convex part 60 is extended in the radial direction of the output member 23, and the cross section of each 4th convex part 60 cut | disconnected along the circumferential direction of the output member 23 becomes convex, for example in axial direction S1. It is formed in a semicircular shape. The length of the third concave portion 57 in the radial direction Y1 of the inner ring 39a is smaller than the length of the fourth convex portion 60 in the radial direction of the output member 23. That is, the strength of the third concave portion 57 is lower than the strength of the fourth convex portion 60.

  When the input member 22 rotates, the rotation of the input member 22 is transmitted to the inner ring 39a by the first convex portion 52 and the second concave portion 54 that are engaged with each other. When the rotation is transmitted from the input member 22 to the inner ring 39a, the rotation of the inner ring 39a is transmitted to the output member 23 by the fourth convex portion 60 and the third concave portion 57 that are engaged with each other. Therefore, the rotation of the input member 22 is transmitted to the output member 23 via the inner ring 39a. Further, since the number of the second concave portions 54 and the number of the fourth convex portions 60 are larger than the number of the first concave portions and the number of the third convex portions 58, respectively, the rotation of the input member 22 is decelerated and output. It is transmitted to the member 23. Furthermore, when rotation is transmitted from the input member 22 to the output member 23, the inner ring 39a performs Coriolis motion (swing motion) around the first axis A1.

FIG. 3 is a side view of the main part of the oscillating gear device 20 showing the engaging part of the input member 22 and the inner ring 39a.
Referring to FIG. 3, the inner ring 39a is formed with a slit 61 having a predetermined depth D1 extending from the bottom 54a of each second recess 54 in the depth direction corresponding to the axial direction X1 of the inner ring 39a. Each slit 61 is formed along a line that bisects the corresponding second recess 54 in the circumferential direction Z1. Each slit 61 extends in the radial direction Y1 (a direction perpendicular to the paper surface in FIG. 3). With respect to the radial direction Y1, the length of each slit 61 is equal to the length of the second convex portion 55 and the second concave portion 54, for example.

  Each slit 61 has a pair of inner side surfaces 62 facing the circumferential direction Z1 and a bottom surface 63. Each inner side surface 62 may be formed on a flat surface extending along the axial direction X1 or an inclined surface inclined so that the width W1 of the slit 61 with respect to the circumferential direction Z1 increases as it approaches the entrance of the slit 61. May be. One end of each inner side surface 62 is smoothly connected to the bottom surface 63. The cross section of the bottom surface 63 cut along the circumferential direction Z <b> 1 is formed in, for example, a semicircular shape that is convex toward the bottom side of the slit 61.

  Each second convex portion 55 has a length L1 in the axial direction X1 that is increased by the slit 61. Moreover, each 2nd convex part 55 can be considered as a cantilever with which one edge part regarding the axial direction X1 was supported. Therefore, when a load is applied to the end 55a (free end) on the second end face 53 side of each second protrusion 55, the second protrusion 55 bends in the circumferential direction Z1 with a predetermined amount of bending. The amount of bending of the second convex portion 55 at this time is expressed by, for example, the following (Expression 1) indicating the amount of bending of the cantilever.

(Formula 1) y = ML ³ / (3EI)
y: Deflection amount of the beam, M: Bending moment, L: Length of the beam, E: Young's modulus, I: Second moment of section From the equation (1), the deflection amount y of the cantilever beam is the length L of the beam. Increases in proportion to the cube of. Therefore, as in this embodiment, the slit 61 is formed in the inner ring 39a, and the length L1 of each second convex portion 55 with respect to the axial direction X1 is increased, whereby a load is applied to the end portion 55a of the second convex portion 55. It is possible to greatly increase the amount of bending of the second convex portion 55 when is added.

  When rotation is transmitted from the input member 22 to the inner ring 39a, a load related to the circumferential direction Z1 is transmitted from the first convex portion 52 to the end portion 55a of the second convex portion 55. Therefore, the 2nd convex part 55 receives a load from the 1st convex part 52, and bends in the circumferential direction Z1. Accordingly, the plurality of first convex portions 52 are engaged with the plurality of second concave portions 54, respectively, and the meshing rate between the first convex portions 52 and the second concave portions 54 is increased. Therefore, the contact area between the input member 22 and the inner ring 39a during rotation transmission increases.

  On the other hand, although not shown, the inner ring 39a is formed with a slit 61 extending from the bottom of each third recess 57 in the axial direction X1 of the inner ring 39a. Therefore, the length of each third convex portion 58 with respect to the axial direction X1 is increased by the slit 61. Therefore, when rotation is transmitted from the inner ring 39a to the output member 23, when a load related to the circumferential direction Z1 is applied to the third convex portion 58, the third convex portion 58 bends in the circumferential direction Z1. Thereby, the plurality of fourth convex portions 60 are engaged with the plurality of third concave portions 57, respectively, and the meshing rate between the fourth convex portions 60 and the third concave portions 57 is increased. Therefore, the contact area between the output member 23 and the inner ring 39a during rotation transmission increases.

  As described above, in the present embodiment, by forming the slit 61 in the inner ring 39a, the second convex portion 55 and the third convex portion 58 of the inner ring 39a can be easily provided when rotation is transmitted from the input member 22 to the output member 23. And the engagement ratio between the first protrusion 52 and the second recess 54 and the engagement ratio between the fourth protrusion 60 and the third recess 57 can be increased. As a result, the contact area between the input member 22 and the inner ring 39a and the contact area between the output member 23 and the inner ring 39a during rotation transmission can be increased. Therefore, when the rotation is transmitted from the input member 22 to the output member 23, the stress applied to the inner ring 39a can be dispersed to prevent the stress from being concentrated on the inner ring 39a. Thereby, the intensity | strength of the inner ring | wheel 39a can be improved and by extension, the intensity | strength of the rocking | fluctuation type gear apparatus 20 can be improved. In this embodiment, the strength of the inner ring 39a is the lowest among the input member 22, the output member 23, and the inner ring 39a. Therefore, the strength of the oscillating gear device 20 is improved by improving the strength of the inner ring 39a. Can be improved efficiently.

  Further, since the slit 61 is formed so as to extend from the bottoms of the second concave portions 54 and the third concave portions 57, the swinging type without lowering the breaking strength of the second convex portions 55 and the third convex portions 58. The strength of the gear device 20 can be improved. Furthermore, since the cross section of the bottom surface 63 along the circumferential direction Z1 is formed in a semicircular shape that protrudes toward the bottom side of the slit 61, when rotation is transmitted from the input member 22 to the output member 23, It is possible to prevent stress from concentrating on the base end portion of the second convex portion 55 and the base end portion of the third convex portion 58. Thereby, the strength of the inner ring 39a is further improved, and the strength of the oscillating gear device 20 is further improved.

  Further, by increasing the contact area between the input member 22 and the inner ring 39a during rotation transmission, it is possible to reduce the impact when the first convex portion 52 and the second concave portion 54 are engaged. Similarly, by increasing the contact area between the output member 23 and the inner ring 39a during rotation transmission, it is possible to reduce the impact when the fourth convex portion 60 and the third concave portion 57 are engaged. Thereby, when rotation is transmitted from the input member 22 to the output member 23, noise generated from the oscillating gear device 20 can be reduced.

  Furthermore, since the strength of the oscillating gear device 20 can be improved, the size of the oscillating gear device 20 can be reduced while maintaining the magnitude of torque that can be transmitted by the oscillating gear device 20 at a certain value or more. can do. Thereby, the transmission ratio variable mechanism 5 can be reduced in size. Therefore, it is possible to provide a transmission ratio variable mechanism 5 that is small in size and low in noise. Similarly, it is possible to provide the electric power steering apparatus 1 that is small in size and low in noise.

  Furthermore, in this embodiment, the pitch circle diameter (PCD) of the 1st convex part 52, the 2nd recessed part 54, the 3rd recessed part 57, and the 4th convex part 60 can be made small. If the pitch circle diameter is reduced, the peripheral speeds of the first convex portion 52, the second concave portion 54, the third concave portion 57, and the fourth convex portion 60 when the rotation is transmitted from the input member 22 to the output member 23 are reduced. . Therefore, it is possible to reduce the impact when the first convex portion 52 and the second concave portion 54 are engaged and the impact when the fourth convex portion 60 and the third concave portion 57 are engaged. Thereby, the noise which arises from the rocking | fluctuation type gear apparatus 20 at the time of rotation transmission can be made still smaller.

  Further, when the pitch circle diameter is reduced, the thickness of the second convex portion 55 and the third convex portion 58 is reduced with respect to the circumferential direction Z1, and the strength of each second convex portion 55 and each third convex portion 58 is reduced. However, by increasing the meshing rate between the first convex portion 52 and the second concave portion 54 and the meshing rate between the fourth convex portion 60 and the third concave portion 57, it is possible to prevent the strength of the inner ring 39a from being lowered as a whole. Can do. As a result, it is possible to further reduce the noise generated from the oscillating gear device 20 during transmission of rotation while maintaining the magnitude of the torque that can be transmitted by the oscillating gear device 20 at a certain value or more.

FIG. 4 is a side view of the main part of the oscillating gear device 220 showing the engaging part of the input member 22 and the inner ring 239a according to the second embodiment of the present invention. 4, the same components as those shown in FIGS. 1 to 3 described above are denoted by the same reference numerals as those in FIG.
Referring to FIG. 4, the main difference between the second embodiment and the first embodiment described above is that the inner ring 239a has a predetermined extension in the axial direction X1 of the inner ring 239a from the top 255a of each second protrusion 255. That is, a slit 261 having a depth D2 is formed. The depth D2 of the slit 261 is greater than the height H2 of the second convex portion 255. Moreover, each slit 261 is formed along the line which bisects the 2nd convex part 255 corresponding to the circumferential direction Z1. Each slit 261 extends in the radial direction Y1 (the direction perpendicular to the paper surface in FIG. 4). Regarding the radial direction Y1, the length of each slit 261 is equal to the length of the second convex portion 255 and the second concave portion 254, for example.

  Each slit 261 has a pair of inner side surfaces 262 facing the circumferential direction Z1 and a bottom surface 263. Each inner surface 262 may be formed, for example, as a flat surface extending along the axial direction X1, or an inclined surface that is inclined so that the width W2 of the slit 61 in the circumferential direction Z1 widens as it approaches the entrance of the slit 261. It may be formed. One end of each inner surface 262 is smoothly connected to the bottom surface 263. The cross section of the bottom surface 263 cut along the circumferential direction Z <b> 1 is formed in, for example, a semicircular shape that is convex toward the bottom side of the slit 261.

  In addition, each second convex portion 255 has two divided bodies 64 that face each other with the corresponding slit 261 sandwiched in the circumferential direction Z1. Each divided body 64 can be regarded as a cantilever beam supported at one end in the axial direction X1. Further, since the depth D2 of each slit 261 is greater than the height H2 of the second convex portion 255, the length L2 of each divided body 64 is increased. Therefore, each divided body 64 is easily bent in the circumferential direction Z1 with the base end portion as a fulcrum. Further, since the depth D2 of each slit 261 is greater than the height H2 of the second convex portion 255, the thickness T2 of the base end portion of each divided body 64 is large. Thereby, the strength of each divided body 64 is improved.

  When rotation is transmitted from the input member 22 to the inner ring 239a, a load is transmitted from the first convex portion 52 to the end portion 64a (free end) of the divided body 64 in the circumferential direction Z1. Thereby, the division body 64 bends in the circumferential direction Z1, and the plurality of first protrusions 52 engage with the plurality of second recesses 254, respectively. Therefore, the meshing rate of the 1st convex part 52 and the 2nd recessed part 254 increases. Therefore, the contact area between the input member 22 and the inner ring 239a during rotation transmission increases.

  On the other hand, although not shown, the inner ring 239a is formed with a slit 261 extending from the top of each third convex portion in the axial direction X1 of the inner ring 239a. Therefore, each 3rd convex part contains the two division body which opposes on both sides of a slit in the circumferential direction Z1. Therefore, when the rotation is transmitted from the inner ring 239a to the output member 23, with respect to the circumferential direction Z1, when a load is applied to the divided body of the third convex portion, the divided body bends in the circumferential direction Z1. Thereby, the plurality of fourth convex portions 60 are respectively engaged with the plurality of third concave portions, and the meshing rate between the fourth convex portions 60 and the third concave portions is increased. Therefore, the contact area between the output member 23 and the inner ring 239a during rotation transmission increases.

  As described above, in the second embodiment, as in the first embodiment, the contact area between the input member 22 and the inner ring 239a and the contact area between the output member 23 and the inner ring 239a during rotation transmission can be increased. . Therefore, when the rotation is transmitted from the input member 22 to the output member 23, the stress applied to the inner ring 239a can be dispersed to prevent the stress from being concentrated on the inner ring 239a. Thereby, the intensity | strength of the inner ring | wheel 239a can be improved and the intensity | strength of the rocking | fluctuation type gear apparatus 220 can be improved by extension.

  Moreover, since the depth D2 of the slit 261 is larger than the height H2 of the second convex portion 255 that is a convex portion with a slit, the depth D2 of the slit 261 is equal to the height H2 of the second convex portion 255. Compared with the case where it is equal to, each division body 64 becomes easy to bend, and thickness T2 of the base end part of each division body 64 can be made thick. As a result, the strength of the second convex portion 255 can be improved, and as a result, the strength of the oscillating gear device 220 can be improved.

  Furthermore, since the strength of the oscillating gear device 220 can be improved, the oscillating gear device 220 can be reduced in size as in the first embodiment. Thereby, the transmission ratio variable mechanism 5 can be reduced in size. Therefore, it is possible to provide a transmission ratio variable mechanism 5 that is small in size and low in noise. Similarly, it is possible to provide the electric power steering apparatus 1 that is small in size and low in noise.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the contents of the above-described embodiments, and various modifications can be made within the scope of the claims. For example, in the first embodiment described above, the first convex portion 52 having a semicircular cross section is provided in the input member 22, and the second concave portion 54 having a semicircular cross section corresponding to the first convex portion 52 is provided in the inner ring 39a. However, the present invention is not limited to this.

  More specifically, for example, a second convex portion 355 having a semicircular cross section is provided on the inner ring 339a, and a semicircular cross section corresponding to the second convex portion 355 as in the oscillating gear device 320 shown in FIG. A first concave portion 65 may be provided on the input member 322. Similarly, a second convex part 455 having a semicircular cross section is provided on the inner ring 439a, for example, as in the oscillating gear device 420 shown in FIG. 6, and a semicircular second cross section corresponding to the second convex part 455 is provided. One recess 66 may be provided in the input member 422. In this case, as shown in FIG. 5, a slit 361 extending in the axial direction X1 from the bottom 354a of the second recess 354 may be formed in the inner ring 339a, and as shown in FIG. A slit 461 extending in the axial direction X1 from the top 455a may be formed in the inner ring 439a. Although not shown, a third convex portion having a semicircular cross section may be provided in the inner ring, and a fourth concave portion having a semicircular cross section corresponding to the third convex portion may be provided in the output member.

  In the first embodiment described above, the first convex portion 52 and the input member 22 are integrally formed with a single member, and the fourth convex portion 60 and the output member 23 are integrally formed with a single member. However, the present invention is not limited to this. More specifically, for example, as shown in FIG. 7, a fitting groove 67 is formed in the first end surface 51 of the input member 522, and a cylindrical needle pin 68 is fitted into the fitting groove 67. The first convex portion 552 having a semicircular cross section may be formed. Although not shown, the same applies to the fourth convex portion.

In the above-described embodiment, the case where the slits 61, 261, 361, and 461 are formed in the inner rings 39a, 239a, 339a, and 439a has been described . However, in the reference embodiment of the present invention , slits may be formed in the input members 22, 322, 422, and 522. Similarly, in the reference embodiment of the present invention , a slit may be formed in the output member 23.
In the first embodiment described above, the case where the oscillating gear device 20 is provided in the transmission ratio variable mechanism 5 and the electric power steering device 1 has been described. However, the oscillating gear device 20 has a variable transmission ratio. Not only the mechanism 5 and the electric power steering device 1 but also other devices may be provided. Further, the transmission ratio variable mechanism 5 including the oscillating gear device 20 is not limited to the electric power steering device 1 and may be provided in other devices.

  In addition, various design changes can be made within the scope of matters described in the claims.

DESCRIPTION OF SYMBOLS 1 ... Electric power steering device (steering device for vehicles), 2 ... Steering member, 5 ... Transmission ratio variable mechanism, 4L, 4R ... Wheel, 12 ... Second shaft (wheel side Members), 20, 220, 320, 420... Oscillating gear device, 21... Transmission ratio variable mechanism motor (electric motor), 22, 322, 422, 522. Output member, 39a, 239a, 339a, 439a ... inner ring (intermediate member), 52, 552 ... first convex part (convex part of input member), 54, 254, 354 ... second concave part ( (Concave part of intermediate member), 54a, 354a (bottom of second concave part), 55, 255, 355, 455 ... second convex part (convex part of intermediate member), 57 ... third concave part ( Intermediate member concave portion), 58... Third convex portion (intermediate member convex portion), 60. 4th convex part (convex part of output member), 61, 261, 361, 461... Slit, 65, 66... First concave part (concave part of input member), 255a, 455a. Top), A1 ... first axis, B1 ... second axis, D1, D2 ... depth, H2 ... height, X1 ... axial direction, θ1 ... Steering angle, θ2 ... steering angle

Claims (4)

An input member and an output member each having a central axis on the first axis and rotatable about the first axis; the input member and the input member so as to allow differential rotation of the input member and the output member; An intermediate member for connecting the output member,
The intermediate member has a central axis on a second axis inclined with respect to the first axis, and is rotatable about the second axis.
The intermediate member includes a plurality of second concave portions or second convex portions that are engageable with the plurality of first convex portions or first concave portions arranged in an arc shape on the input member, and an arc shape on the output member. A plurality of third concave portions or third convex portions that can be engaged with the plurality of arranged fourth convex portions or fourth concave portions are arranged in an arc shape,
The length of the second concave portion or the second convex portion with respect to the radial direction of the intermediate member is smaller than the length of the first convex portion or the first concave portion with respect to the radial direction of the input member,
The length of the third concave portion or the third convex portion with respect to the radial direction of the intermediate member is smaller than the length of the fourth convex portion or the fourth concave portion with respect to the radial direction of the output member,
The oscillating gear device, wherein the intermediate member is formed with a slit having a predetermined depth extending from the bottom of the concave portion of the member along the axial direction of the member. An input member and an output member each having a central axis on the first axis and rotatable about the first axis; the input member and the input member so as to allow differential rotation of the input member and the output member; An intermediate member for connecting the output member,
The intermediate member has a central axis on a second axis inclined with respect to the first axis, and is rotatable about the second axis.
The intermediate member includes a plurality of second concave portions or second convex portions that are engageable with the plurality of first convex portions or first concave portions arranged in an arc shape on the input member, and an arc shape on the output member. A plurality of third concave portions or third convex portions that can be engaged with the plurality of arranged fourth convex portions or fourth concave portions are arranged in an arc shape,
The length of the second concave portion or the second convex portion with respect to the radial direction of the intermediate member is smaller than the length of the first convex portion or the first concave portion with respect to the radial direction of the input member,
The length of the third concave portion or the third convex portion with respect to the radial direction of the intermediate member is smaller than the length of the fourth convex portion or the fourth concave portion with respect to the radial direction of the output member,
The intermediate member is formed with a slit having a predetermined depth extending from the top of the convex portion of the member along the axial direction of the member, and the predetermined depth is based on a height value of the convex portion of the member. An oscillating gear device characterized by being large. The oscillating gear device according to claim 1 or 2,
An electric motor for driving the intermediate member,
A transmission ratio variable mechanism capable of changing a ratio of a rotation angle of the output member to a rotation angle of the input member.   A vehicle steering apparatus capable of changing a transmission ratio, which is a ratio of a wheel turning angle to a steering angle of a steering member, using the transmission ratio variable mechanism according to claim 3, wherein the input member is connected to the steering member. A vehicle steering apparatus in which the output member is connected to a wheel-side member.

Images