JP2007186021A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device, capable of reducing irregularity and noise of rotation torque of a worm shaft. <P>SOLUTION: The electric power steering device is provided with the worm shaft 20 and a worm wheel 21 as a reducer 19. The worm shaft 20 is rotatably supported by a housing 19a through first and second bearings 29 and 30 respectively corresponding to first and second end parts 22 and 23. The first end part 22 of the worm shaft 20 is connected through a joint 27 to a rotation shaft 28 of an electric motor 18. Inside the joint 27, an elastic member 38 to provide prepressure through the worm shaft 20 to the first bearing 29 is provided. As a projection 28a of the rotary shaft 28 is engaged win an engagement hole 28a of the elastic member 38, inclination of the elastic member 38 to the rotation shaft 28 is prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric power steering device that generates a steering assist force by an electric motor.

  2. Description of the Related Art Some electric power steering systems (EPS) for vehicles include an electric motor for assisting steering and a speed reducer that amplifies the output of the electric motor. For example, a column type EPS includes a worm shaft as a speed reducer and a worm wheel that meshes with the worm shaft. The worm shaft and the worm wheel amplify the output of the electric motor by decelerating the rotation of the output shaft of the electric motor. Then, the steering operation is torque-assisted by transmitting the amplified output of the electric motor to the steering mechanism.

Further, the column type EPS has a housing for housing the worm shaft and the worm wheel, and first and second rolling bearings disposed at the first and second end portions of the worm shaft, respectively. The worm shaft is rotatably supported by the housing via the first and second rolling bearings. Moreover, the 1st end part of the worm shaft is connected with the rotating shaft of the electric motor through the joint (for example, refer patent document 1).
JP 2002-145083 A

However, in the invention described in Patent Document 1, for example, when the vehicle body vibrates by traveling on a rough road or the like, noise due to the internal clearance of the first rolling bearing may occur.
Therefore, the inventor of the present application interposes an elastic member inside the joint, applies an axial preload to the first rolling bearing via the worm shaft, and removes the internal clearance of the first rolling bearing.
However, in the above-described structure, the elastic member is inclined with respect to the rotation shaft of the electric motor, and the rotation torque of the worm shaft may vary due to the inclination of the elastic member.

  The present invention has been made based on such a background, and an object thereof is to provide an electric power steering apparatus capable of reducing variation in rotational torque of the worm shaft and noise.

  In order to achieve the above object, the present invention includes a transmission mechanism (19) for transmitting the power of the steering assisting electric motor (18) to the steering mechanism (A). In the electric power steering apparatus including a drive gear (20) having two end portions (22, 23) and a driven gear (21) meshing with the drive gear, the first and second end portions of the drive gear are respectively First and second bearings (29, 30) that are rotatably supported, and a joint (27) that couples the rotary shaft (28) of the electric motor and the first end of the drive gear so as to transmit torque. And a bearing preload elastic member (38) interposed between the rotating shaft and the first end of the drive gear and for applying a preload in the axial direction (X1) to the first bearing via the drive gear. The bearing preload elastic member is fitted to the rotating shaft of the electric motor. An electric power steering device (1) having a fitting portion (38a).

According to the present invention, noise can be reduced by removing the internal clearance of the first bearing by the elastic member for bearing preload. In addition, since the bearing preload elastic member is fitted to the rotating shaft of the electric motor, it is possible to prevent the bearing preload elastic member from tilting with respect to the rotating shaft, and as a result, suppressing fluctuations in the transmission torque caused by the tilt, etc. can do.
In the present invention, the rotating shaft of the electric motor has a protrusion (28a), and the fitting portion of the bearing preload elastic member has a fitting hole (38a) in which the protrusion of the rotating shaft is fitted. May include. In this case, it is only necessary to fit the protrusion of the rotating shaft into the fitting hole of the elastic member for preloading the bearing, so that the assemblability is good.

  The present invention also includes a housing (19a) that accommodates the transmission mechanism, and the first bearing is restricted in axial movement by the inner ring (29b) that can move integrally with the drive gear in the axial direction and the housing. In some cases, the outer ring (29a) and the rolling element (29c) interposed between the inner ring and the outer ring may be included. In this case, the internal clearance of the first bearing can be removed by applying the axial preload to the first bearing by the elastic member for bearing preload.

  Further, the present invention provides a housing for housing the transmission mechanism, and the second bearing is provided in the housing so that the second bearing can be biased in a direction (Y1, Y2) in which the distance (D1) between the centers of both gears is longer or shorter. A supporting hole (37) for backlash removal, and a biasing member for backlash removal (36) for removing backlash between the two gears by biasing in the direction of reducing the distance between the centers through the second bearing. May be provided. In this case, the backlash removing urging member removes the backlash between the two gears, thereby preventing noise.

  In the present invention, the joint includes first and second members (39, 40) connected to the rotary shaft and the first end of the drive gear, respectively, so as to be integrally rotatable, and the first and second members. There is a case where at least a part of the elastic member for preloading the bearing is accommodated in the urging member for torque transmission. In this case, space saving of the electric power steering device can be achieved.

  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.

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering apparatus 1 according to an embodiment of the present invention. Referring to FIG. 1, an electric power steering apparatus 1 includes a steering shaft 3 connected to a steering member 2 such as a steering wheel, a pinion shaft 5 connected to the steering shaft 3 via an intermediate shaft 4, and a pinion shaft. 5 includes a rack 7 that meshes with the pinion 6 formed in 5, and a rack bar 8 as a turning shaft that extends in the left-right direction of the automobile. The pinion shaft 5 and the rack bar 8 constitute a rack and pinion mechanism A as a steering mechanism.

The steering shaft 3 is divided into an input shaft 9 connected to the steering member 2 and an output shaft 10 connected to the pinion shaft 5. The input shaft 9 and the output shaft 10 are connected via a torsion bar 11 so as to be relatively rotatable on the same axis.
The rack bar 8 is supported by the housing 12 so as to be linearly reciprocable through a plurality of bearings (not shown). Both ends of the rack bar 8 protrude to both sides of the housing 12, and steered wheels 14 are connected to the ends via tie rods 13 and knuckle arms (not shown), respectively.

By operating the steering member 2, the steering shaft 3 rotates. The rotation of the steering shaft 3 is converted into a linear reciprocating motion in the axial direction of the rack bar 8 via the pinion 6 and the rack 7. Thereby, steering of the steering wheel 14 is achieved.
The steering torque applied to the steering member 2 is detected by a torque sensor 15 provided in the vicinity of the steering shaft 3 based on the amount of relative rotational displacement between the input shaft 9 and the output shaft 10. The torque value detected by the torque sensor 15 is given to an ECU 16 (Electronic Control Unit). The ECU 16 drives and controls the steering assisting electric motor 18 via the drive circuit 17 based on a torque value, a vehicle speed given from a vehicle speed sensor (not shown), or the like.

The rotational driving force of the electric motor 18 is amplified by the speed reducer 19, transmitted to the output shaft 10 of the steering shaft 3, and further converted into a linear reciprocating motion of the rack bar 8 via the pinion shaft 5. This assists steering.
FIG. 2 is a cross-sectional view showing the configuration of the speed reducer 19 provided in the electric power steering apparatus 1 of FIG. 1 and the vicinity thereof. Referring to FIG. 2, the speed reducer 19 includes a worm shaft 20 as a drive gear that is rotationally driven by an electric motor 18, and a worm wheel 21 as a driven gear that meshes with the worm shaft 20.

  The worm shaft 20 has a first end portion 22 and a second end portion 23, and a worm 240 is formed in an intermediate portion 24 between the first end portion 22 and the second end portion 23. Yes. The first end 22 and the second end 23 have a smaller diameter than the worm 240. The first end 22 includes a supported portion 25 supported by a first bearing 29 described later and a connecting portion 26 extending coaxially from the supported portion 25. An annular positioning step portion 24 a is formed between the intermediate portion 24 and the supported portion 25. The connecting portion 26 has a smaller diameter than the supported portion 25 and is connected to the rotating shaft 28 of the electric motor 18 via a joint 27 so as to transmit torque. As a result, the output of the electric motor 18 is transmitted to the worm shaft 20.

  The worm wheel 21 includes an annular cored bar 21a coupled to the output shaft 10 so as to be integrally rotatable, and a synthetic resin member 21b surrounding the cored bar 21a and having teeth formed on the outer periphery. The cored bar 21a is inserted into the mold during resin molding of the synthetic resin member 21b, for example. The cored bar 21a is fitted and connected to the output shaft 10 of the steering shaft 3 by press fitting, for example. Thereby, the worm wheel 21 can rotate integrally with the output shaft 10 and cannot move in the axial direction. The worm shaft 20 and the worm wheel 21 are accommodated in a housing 19a.

  The supported portion 25 at the first end 22 of the worm shaft 20 is supported by a first bearing 29 held by the housing 19a. On the other hand, the second end 23 of the worm shaft 20 is supported by a second bearing 30 held by the housing 19a. As the first and second bearings 29 and 30, rolling bearings such as radial ball bearings are used, for example. The first bearing 29 has an outer ring 29a, an inner ring 29b, and a rolling element 29c. The second bearing 30 includes an outer ring 30a, an inner ring 30b, and a rolling element 30c.

  The inner ring 29b of the first bearing 29 is fitted to the outer periphery of the supported portion 25 so as to be rotatable integrally with the outer circumference of the supported portion 25 and movable in the axial direction X1 of the worm shaft 20, and the outer ring 29a is formed in the housing 19a. The support hole 33 is held so as not to rotate. Further, the inner ring 29b is sandwiched in the axial direction X1 by a second member 40 described later of the joint 27 and the annular positioning step portion 24a. The outer ring 29a is axially formed by an annular step 33a formed at the bottom of the first support hole 33 and an arcuate retaining ring 34 held in an annular groove 33b at the entrance of the first support hole 33. It is sandwiched between X1. An elastic body 35 that receives the end surface of the outer ring 29 a is interposed between the retaining ring 34 and the end surface of the outer ring 29 a facing the retaining ring 34, and the elastic body 35 is bonded to the end surface of the retaining ring 34. . The outer ring 29a is elastically supported by the elastic body 35 in the axial direction X1.

  The inner ring 30b of the second bearing 30 is fitted to the outer periphery of the second end portion 23 so as to be integrally rotatable and integrally movable in the axial direction X1, and the outer ring 30a is interposed through an urging member 36 having elasticity. The second support hole 37 is formed in the housing 19a. The urging member 36 functions as a backlash removing urging member for removing backlash between the worm shaft 20 and the worm wheel 21. One end of the inner ring 30b on the electric motor 18 side is positioned in the axial direction X1 of the worm shaft 20 by an annular positioning step portion 24b formed between the second end portion 23 and the intermediate portion 24 of the worm shaft 20. Yes. One end of the outer ring 30a opposite to the electric motor 18 is received in the axial direction X1 by a receiving portion 36a formed on the urging member 36.

Next, the support state of the second end 23 of the worm shaft 20 will be described.
3 is a cross-sectional view taken along line III-III in FIG. 2, and FIG. 4 is a cross-sectional view showing a state where the worm shaft 20 and the second bearing 30 are not attached to the biasing member 36 in FIG. is there.
Referring to FIGS. 2 and 3, the second end 23 of the worm shaft 20 is connected to the second support 30 via the second bearing 30 and the biasing member 36 fitted to the second end 23. It is supported by the hole 37.

The second support hole 37 of the housing 19 a is a circular hole, and is disposed on the same axis as the first support hole 33. A recess 37 a is formed in a part of the inner peripheral surface of the second support hole 37.
The backlash removal urging member 36 includes a cylindrical portion 360, an end wall 361 that closes one end of the cylindrical portion 360, and an annular flange 362 that extends radially outward from the end wall 361.

The cylindrical portion 360 of the urging member 36 is elastically fitted into the second support hole 37, and the flange 362 of the urging member 36 is in contact with the edge 37 b of the opening of the second support hole 37. Thereby, the sealing performance of the second support hole 37 is ensured. That is, the urging member 36 also functions as a sealing member for the second support hole 37.
In a state where the cylindrical portion 360 of the urging member 36 is fitted in the second support hole 37 and the second bearing 30 is not attached to the cylindrical portion 360, as shown in FIG. The outer peripheral surface and the inner peripheral surface are both cylindrical surfaces and are eccentric from each other. Specifically, the central axis C1 of the cylindrical surface formed by the inner peripheral surface of the cylindrical portion 360 is the same as the central axis C2 of the cylindrical surface formed by the outer peripheral surface of the cylindrical portion 360 (the central axis of the second support hole 37). ) Is offset by a predetermined distance d in the direction Y2 in which the center distance D1 between the worm shaft 20 and the worm wheel 21 is shortened.

  Therefore, when the second bearing 30 supporting the second end portion 23 of the worm shaft 20 is fitted into the cylindrical portion 360, the cylindrical portion 360 is connected to the worm wheel 21 side as shown in FIG. The substantially semicircular portion 363 on the opposite side is elastically compressed, and a gap is formed between the inner peripheral surface of the substantially semicircular portion 364 on the worm wheel 21 side of the cylindrical portion 360 and the outer ring 30a of the second bearing 30. Is formed.

Thus, the elastically compressed portion of the cylindrical portion 360 moves the second end portion 23 of the worm shaft 20 through the second bearing 30 to the worm wheel 21 side (that is, the worm shaft 20 and the worm wheel 21). The backlash between the worm shaft 20 and the worm wheel 21 is removed by elastically urging in the direction Y2) in which the center-to-center distance D1 is shortened.
Further, the cylindrical portion 360 of the urging member 36 bulges a part in the circumferential direction of the outer peripheral surface of the cylindrical portion 360 outward in the radial direction, so that the above-mentioned part of the cylindrical portion 360 is another part. The thick portion is fitted into the concave portion 37 a of the second support hole 37. That is, the part of the cylindrical part 360 that is most elastically compressed by the second bearing 30 is thicker than the other parts. Thereby, the sag of the urging member 36 due to elastic deformation is prevented, and the durability of the urging member 36 is improved. Moreover, since the cylindrical part 360 of the urging member 36 is disposed so as to surround the outer periphery of the outer ring 30a, the outer ring 30a and the second support hole 37 are prevented from making a metal hitting and generating sound. Can do.

Next, the connection between the rotating shaft 28 of the electric motor 18 and the first end 22 of the worm shaft 20 will be described.
5 is a cross-sectional view taken along line IV-IV in FIG. 2, and FIG. 6 is an exploded perspective view of the joint 27. First, referring to FIG. 2, the rotating shaft 28 of the electric motor 18 and the first end portion 22 of the worm shaft 20 are connected via a joint 27 so that power can be transmitted. Further, an elastic member 38 that applies a preload in the axial direction X <b> 1 to the first bearing 29 via the worm shaft 20 is disposed inside the joint 27.

The joint 27 is connected to the first member 39 connected to the rotating shaft 28 of the electric motor 18 so as to be integrally rotatable, and to the connecting portion 26 of the first end portion 22 of the worm shaft 20 so as to be integrally rotatable. And a torque transmission member 41 that is interposed between the first and second members 39 and 40 and transmits torque from the first member 39 to the second member 40.
Referring to FIG. 6, the first member 39 is made of, for example, metal, and has a ring-shaped first main body portion 42 and a plurality of first main body portions 42 that protrude from one axial end surface of the first main body portion 42. First engaging projections 43. A first fitting hole 44 for fitting the rotating shaft 28 of the electric motor 18 is formed in the first main body portion 42, and the first engagement protrusion 43 is formed in the first main body portion 42. Are arranged at equal intervals in the circumferential direction. Further, the first engagement protrusion 43 has a pair of torque transmission surfaces 45 opposed to the circumferential direction of the first main body portion 42.

  The second member 40 is made of, for example, metal, and has an annular second main body portion 46 and a plurality of second engaging protrusions that are formed to protrude from one end surface of the second main body portion 46 in the axial direction. 47. The second main body portion 46 is formed with a second fitting hole 48 for fitting the connecting portion 26 of the first end portion 22 of the worm shaft 20. The second main body portion 46 is arranged at equal intervals in the circumferential direction. Further, the second engagement protrusion 47 has a pair of torque transmission surfaces 49 facing the circumferential direction of the second main body portion 46.

The torque transmission member 41 is made of, for example, synthetic rubber or synthetic resin, and includes an annular main body 50 and a plurality of engagement arms 51 that extend radially from the peripheral surface of the main body 50. The plurality of engagement arms 51 are arranged at equal intervals in the circumferential direction of the main body portion 50, and each engagement arm 51 has a pair of torque transmission surfaces 52 that face each other in the circumferential direction of the main body portion 50. .
As shown in FIG. 5, the first member 39, the second member 40, and the torque transmission member 41 are arranged so that the first engagement protrusion 43, the second engagement protrusion 47, and the engagement arm 51 are engaged with each other. It is assembled. Specifically, the first engagement protrusion 43 and the second engagement protrusion 47 are meshed with the engagement arm 51 sandwiched in the circumferential direction. The torque transmission surface 45 of the first member 39 and the torque transmission surface 49 of the second member 40 are in contact with the torque transmission surface 52 of the torque transmission member 41, respectively. As a result, the output of the electric motor 18 is transmitted to the worm shaft 20 via the joint 27.

  The elastic member 38 is formed in a cylindrical shape by synthetic rubber or synthetic resin, for example, and has a fitting hole 38a into which a protrusion 28a formed on the rotating shaft 28 of the electric motor 18 is fitted. The protrusion 28 a protrudes in the axial direction X <b> 1 from one end of the rotating shaft 28 and is coaxial with the rotating shaft 28. The protrusion 28a is fitted into the fitting hole 38a, for example, by press fitting. Thereby, the elastic member 38 is prevented from inclining with respect to the rotating shaft 28. That is, the coaxiality of the rotating shaft 28 and the elastic member 38 is maintained.

  A part of the elastic member 38 is accommodated in the inner periphery of the torque transmission member 41. Further, the elastic member 38 is interposed between the first and second members 39 and 40 while being elastically compressed. The reaction force due to the elastic compression of the elastic member 38 is transmitted to the first bearing 29 via the second member 40 and the worm shaft 20, and a preload in the axial direction X <b> 1 is applied to the first bearing 29. . Thereby, the internal clearance of the first bearing 29 is removed.

  As described above, according to this embodiment, the preload in the axial direction X1 is applied to the first bearing 29 by the elastic member 38 via the second member 40 and the worm shaft 20, so that the inside of the first bearing 29 The gap is removed. Thereby, the noise resulting from the internal clearance of the first bearing 29 can be reduced. Further, since the elastic member 38 is fitted to the rotating shaft 28 of the electric motor 18, the axis of the elastic member 38 can be prevented from being inclined with respect to the axis of the rotating shaft 28. As a result, the transmission caused by the inclination can be prevented. Torque fluctuations can be suppressed.

  Further, by urging the worm shaft 20 toward the worm wheel 21 by the urging member 36, it is possible to remove the backlash of the meshed portion of the worm shaft 20 and the worm wheel 21, and to prevent the generation of noise. Further, since the outer periphery of the outer ring 30a of the second bearing 30 is surrounded by the cylindrical portion 360 of the urging member 36, the outer ring 30a and the second support hole 37 are in metal contact and sound is generated. Can be prevented. That is, it is possible to remove backlash and prevent the generation of hitting sound with a single member.

FIG. 7 is a cross-sectional view showing the configuration of the speed reducer 19 and the vicinity thereof according to another embodiment of the present invention. In FIG. 7, the same components as those shown in FIGS. 2 to 6 described above are denoted by the same reference numerals as those in FIGS. 2 to 6, and description thereof is omitted.
Referring to FIG. 7, this embodiment is mainly different from the above-described embodiment in that elasticity is provided between the end surface of inner ring 29 b of first bearing 29 and annular stepped portion 24 a of worm shaft 20. A first support member 31 having an elastic force, and an elastic second support member 32 being interposed between the end surface of the inner ring 30b of the second bearing 30 and the annular step portion 24b of the worm shaft 20. It is in. The first and second support members 31 and 32 are constituted by annular elastic members fitted to the first and second end portions 22 and 23 of the worm shaft 20, respectively. The worm shaft 20 is elastically biased in the corresponding direction of the axial direction X1 by the first and second support members 31 and 32, respectively. That is, the worm shaft 20 is elastically supported in the axial direction X1. Further, as the first and second bearings 29 and 30, for example, angular ball bearings are used.

  According to this embodiment, the same effect as the above-mentioned embodiment can be produced. Further, the first and second support members 31 and 32 elastically support the worm shaft 20 in the axial direction X1, and the first and second bearings 29 and 30 are angular ball bearings having high rigidity in the axial direction X1. Therefore, the support load can be changed linearly with respect to the change in the axial direction X1 of the worm shaft 20, and thereby a stable elastic support characteristic can be obtained with respect to the axial direction X1.

Note that the first and second bearings 29 and 30 may be not only angular ball bearings but also four-point contact ball bearings or tapered roller bearings.
The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims. For example, in the above-described embodiment, the example in which the protrusion 28a of the rotating shaft 28 is fitted into the fitting hole 38a of the elastic member 38 has been described, but the protrusion is formed on the elastic member 38 and the fitting hole is formed in the rotating shaft 28. You may form and fit them. In other words, the rotation shaft 28 and the elastic member 38 may be connected so that the elastic member 38 does not tilt with respect to the rotation shaft 28.

  In the above-described embodiment, the example in which a part of the elastic member 38 is accommodated in the inner periphery of the torque transmission member 41 has been described. However, the entire elastic member 38 is accommodated in the inner periphery of the torque transmission member 41. May be.

It is a mimetic diagram showing a schematic structure of an electric power steering device of one embodiment of the present invention. It is sectional drawing which shows the structure of the reduction gear with which the electric power steering apparatus of FIG. 1 was equipped, and its vicinity. It is sectional drawing which follows the III-III line of FIG. FIG. 4 is a cross-sectional view showing a state where the worm shaft and the second bearing are not attached to the urging member in FIG. 3. It is sectional drawing which follows the IV-IV line of FIG. It is a disassembled perspective view of a coupling. It is sectional drawing which shows the structure of the reduction gear of another embodiment of this invention, and its vicinity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric power steering apparatus, 18 ... Electric motor, 19 ... Reduction gear (transmission mechanism), 19a ... Housing, 20 ... Worm shaft (drive gear), 21 ... Worm wheel (Driven gear), 22 ... first end, 23 ... second end, 27 ... joint, 28 ... rotary shaft, 29 ... first bearing, 30 ... Second bearing, 28a ... projection, 29a ... outer ring (outer ring of first bearing), 29b ... inner ring (inner ring of first bearing), 29c ... rolling element (first Bearing rolling element), 36 ... biasing member (backlash removing biasing member), 37 ... second support hole (support hole), 38 ... elastic member (elastic member for bearing preload), 38a ... fitting hole (fitting part), 39 ... first member, 40 ... second member, 41 ... torque transmission part (Torque urging member for transmitting), A · · · rack-and-pinion mechanism (steering mechanism), D1 · · · center distance, X1 · · · axis, Y1, Y2 ··· length directions

Claims (5)

A transmission mechanism for transmitting the power of the steering assist electric motor to the steering mechanism;
The transmission mechanism includes an electric power steering device including a drive gear having first and second ends and a driven gear meshing with the drive gear.
First and second bearings rotatably supporting the first and second ends of the drive gear, respectively;
A joint for connecting the rotating shaft of the electric motor and the first end of the drive gear so as to transmit torque;
A bearing preloading elastic member interposed between the rotating shaft and the first end of the drive gear, and applying an axial preload to the first bearing via the drive gear;
The electric power steering device according to claim 1, wherein the elastic member for preloading the bearing has a fitting portion that fits with the rotating shaft of the electric motor.   2. The electric motor according to claim 1, wherein the rotating shaft of the electric motor has a protrusion, and the fitting portion of the elastic member for preloading the bearing includes a fitting hole into which the protrusion of the rotating shaft is fitted. Power steering device. The housing according to claim 1 or 2, comprising the transmission mechanism,
The first bearing includes an inner ring capable of moving integrally with the drive gear in the axial direction, an outer ring whose axial movement is restricted by the housing, and a rolling element interposed between the inner ring and the outer ring. Electric power steering device. In Claims 1-3, the housing which stores the above-mentioned transmission mechanism,
A support hole provided in the housing and supporting the second bearing in a direction in which the distance between the centers of both gears is increased or decreased;
An electric power steering apparatus comprising: a backlash removing urging member that removes backlash between the two gears by urging through the second bearing in a direction that shortens the distance between the centers. . 5. The joint according to claim 1, wherein the joint torques the first and second members coupled to the rotary shaft and the first end of the drive gear, respectively, and the first and second members. A torque transmitting urging member coupled to be able to transmit,
An electric power steering apparatus, wherein at least a part of the bearing preload elastic member is accommodated in a torque transmitting urging member.

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