JP2004017887A - Steering device with variable transmission ratio - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device with a variable transmission ratio enhancing durability and hardly generating a noise. <P>SOLUTION: In the steering device 1 for varying the transmission ratio of a steering angle and a steering angle, a motor 4 has a motor housing body 10a; a stator fixed to the motor housing body 10a; and a rotor 14 rotated/driven by the stator 12 and axially projecting a motor shaft 13 to both ends; and a motor end plate 10b for hiding an opening of the motor housing body 10a. The motor housing body 10a made of a metal is press-fitted to a housing 7 made of a metal. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a variable transmission ratio steering device that changes a transmission ratio between a steering angle of a steering wheel and a steering angle of a steering system.
[0002]
[Prior art]
Conventionally, as shown in FIG. 8, a variable transmission ratio steering device disclosed in Japanese Patent Application Laid-Open No. 2000-211151 is known. This variable transmission ratio steering device is fixed to a housing 90 made of metal, an input shaft 91 provided rotatably with the housing 90, an output shaft 92 rotatably supported by the housing 90, and a housing 90. , A motor 93 capable of rotating the motor shaft 93 a, a gear mechanism 94 including a wave gear mechanism provided in the housing 90, a lock mechanism 95 provided in the housing 90, and a shaft coaxial with the input shaft 91 outside the housing 90. And a spiral cable device 96 provided in the device.
[0003]
The input shaft 91 is connected to a steering wheel (not shown) via a constant velocity joint (not shown), and the steering angle of the steering wheel is transmitted to the input shaft 91. Further, the output shaft 92 is connected to a pinion (not shown) via a constant velocity joint (not shown), and the rotation of the pinion translates a rack bar (not shown). Thus, the output shaft 92 transmits the turning angle to the turning system.
[0004]
The motor 93 has a motor housing 97 fixed in a housing 90. The motor housing 97 includes a metal motor housing main body 97a and a resin motor end plate 97b that covers an opening of the motor housing main body 97a. A stator 93c is fixed in the motor housing body 97a, and a rotor 93d that is driven to rotate by the stator 93c is provided in the stator 93c. The motor shaft 93a is fixed to the rotor 93d, and protrudes axially at both ends of the rotor 93d. One end of the motor shaft 93a on the spiral cable device 96 side is rotatably supported by a motor end plate 97b via a ball bearing 90a, and can be fixed to the housing 90 by a lock mechanism 95. On the other hand, the other end of the motor shaft 93a is connected to a gear mechanism 94.
[0005]
The gear mechanism 94 has a wave generator 94a into which the other end of the motor shaft 93a is fitted and which can rotate integrally with the motor shaft 93a. The wave generator 94a includes a cam 941a having an elliptical cross section perpendicular to the axis, and a ball bearing 942a provided on the outer periphery of the cam 941a. The inner ring of the ball bearing 942a is fixed to the outer periphery of the cam 941a, and the outer ring of the ball bearing 942a is elastically deformable via the ball. An annular flexspline 94b that is elastically deformable integrally with the outer ring of the ball bearing 942a is provided on the outer periphery of the wave generator 94a. External teeth are formed on the outer periphery of the flexspline 94b. An annular stay circular spline 94c is formed on the motor 93 side in the housing 90. Inner teeth of the same number as the outer teeth of the flexspline 94b are formed on the inner periphery of the stay circular spline 94c, whereby the staycircular spline 94c meshes with the flexspline 94b. Further, an annular drive circular spline 94d is rotatably supported on the outside of the housing 90 adjacent to the stay circular spline 94c via a bearing metal 90b. Internal teeth having fewer teeth than the outer teeth of the flex spline 94b are formed on the inner periphery of the drive circular spline 94d, so that the drive circular spline 94d also meshes with the flex spline 94b. The drive circular spline 94d is fixed to a movable flange 94e, and the movable flange 94e is fixed to an output shaft 92.
[0006]
The lock mechanism 95 is supported on a lock holder 95a fixed to the outer periphery of one end of the motor shaft 93a on the spiral cable device 95 side, and is pivotally supported on the housing 90 so as to be swingable about a pivot axis parallel to the axis. And a lock bar 95b driven by the A plurality of lock grooves are formed in the outer periphery of the lock holder 95a, and an engagement claw that can engage with the lock groove is formed at one end of the lock bar 95b.
[0007]
The spiral cable device 96 is provided on a cylindrical housing 96a held by a vehicle body (not shown) and inside the housing 96a so as to be rotatable relative to the housing 96a. And a fixed inner cylinder 96b. A flexible flat cable 96c formed by insulating and coating a plurality of lead wires is provided between the housing 96a and the inner cylinder 96b. One end of the flexible flat cable 96c is connected to the inner cylinder 96b. Wound around the inner cylinder 96b, the other end is connected to the housing 96a. A lead wire connected to the flexible flat cable 96c and extending from the inner cylinder 96b is connected to a stator 93c of the motor 93 and the like. A lead wire connected to the flexible flat cable 96c and extending from the housing 96a is not shown of the vehicle body. The battery and the ECU (electronic control unit) are connected by a connector.
[0008]
In this transmission ratio variable steering device, when the driver steers the steering wheel in a state where the engagement claw portion of the lock bar 95b is not engaged with the lock groove of the lock holder 95a, the steering wheel is moved to the housing 90 via the input shaft 91. The steering angle is transmitted. At this time, the motor 93 drives the rotor 93d to rotate in accordance with the steering angle. The rotation of the rotor 93d is transmitted to the gear mechanism 94 via the motor shaft 93a, where it is decelerated and the output shaft 92 is rotationally driven.
[0009]
In a state where the engaging claw portion of the lock bar 95b is engaged with the lock groove of the lock holder 95a, when the driver steers the steering handle, the steering angle is transmitted to the housing 90 via the input shaft 91. At the same time, the steering angle is also transmitted to the motor shaft 93a. The rotation of the motor shaft 93a is also transmitted to the gear mechanism 94, and the output shaft 92 is driven to rotate.
[0010]
In this manner, in this variable transmission ratio steering apparatus, the input shaft 91 and the motor shaft 93a can be locked in an emergency or the like, and the steering system is switched to the steering system with the transmission ratio between the steering angle and the steering angle being varied. The steering angle is transmitted.
[0011]
[Problems to be solved by the invention]
However, the details of the housing 90 and the motor 93 were not clear in the conventional transmission ratio variable steering device. For this reason, a plurality of projections are provided on the outer peripheral surface of the motor end plate 97b of the motor 93 in the circumferential direction so as to protrude radially outward, and when the motor end plate 97b is pressed into the housing 90, the motor end plate 97b is Therefore, the fastening strength due to the interference is weak in all of the radial, axial, and circumferential directions, and the motor 93 cannot be firmly fixed in the housing 90. For this reason, the shaft shake accompanying the rotation of the motor shaft 93a is received by the gear mechanism 94 as a load other than the speed change. For this reason, the teeth of the gear mechanism 94 are adversely affected, and the durability thereof is feared. In addition, the motor shaft 93a may be eccentrically rotated to generate abnormal noise.
[0012]
The present invention has been made in view of the above-described conventional circumstances, and has as an object to solve the problem of providing a variable transmission ratio steering device that has improved durability and hardly causes abnormal noise.
[0013]
[Means for Solving the Problems]
The variable transmission ratio steering device of the present invention is provided with a metal housing, an input shaft that is provided so as to be able to rotate integrally with the housing, and that transmits a steering angle of a steering wheel, and is fixed inside the housing, and is capable of rotating a motor shaft. A motor, an output shaft rotatably supported by the housing and transmitting a steering angle to a steering system, and a motor provided between the motor shaft and the output shaft in the housing to rotate the motor shaft. A gear mechanism for increasing or decreasing the angle and outputting the output to the output shaft, and a transmission ratio variable steering device that varies a transmission ratio between the steering angle and the steering angle.
[0014]
The motor includes a metal motor housing main body, a stator fixed to the motor housing main body, a rotor that is driven to rotate by the stator and that protrudes the motor shaft at both ends in the axial direction, and an opening in the motor housing main body. A motor end plate for concealing the motor housing body, and the motor housing body is press-fitted into the housing.
[0015]
In the variable transmission ratio steering device according to the present invention, the metal motor housing body is press-fitted into the metal housing. For this reason, the fastening strength due to the interference increases in all of the radial, axial, and circumferential directions, and the motor can be firmly fixed in the housing. For this reason, the shaft of the motor shaft is less liable to be shaken, and the gear mechanism does not need to receive a load other than the speed change. Therefore, the teeth of the gear mechanism are hardly adversely affected, the durability is improved, and abnormal noise due to the eccentric rotation of the motor shaft is hardly generated.
[0016]
Therefore, according to the variable transmission ratio steering apparatus of the present invention, the durability can be improved, and abnormal noise can be suppressed.
[0017]
In the variable transmission ratio steering device of the present invention, at least three convex portions are formed on the outer peripheral surface of the motor housing body in the radial direction so as to protrude in the radially outward direction, or are formed on the inner peripheral surface of the housing in the radially inward direction. At least three protrusions may be formed in the direction. If the press-fitting is performed over the entire peripheral surface of the motor housing main body, it is necessary to make the dimensional variation of the outer periphery of the motor housing main body within a tolerance required for press-fitting, which leads to an increase in cost. On the other hand, if the motor housing body is pressed into the housing at as few positions as possible, it is possible to securely fix the motor to the housing while minimizing cost increase. If three convex portions are formed on the outer peripheral surface of the motor housing main body or the inner peripheral surface of the housing, the displacement of the motor with respect to the housing can be reliably prevented.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, first to third embodiments of the present invention will be described with reference to the drawings.
[0019]
(Embodiment 1)
The transmission ratio variable steering device according to the first embodiment is used for a steering device as shown in FIG. In this tearing device, a steering wheel 70 of a vehicle is connected to an upper end of an upper steering shaft 71 as an input shaft via a constant velocity joint (not shown). The lower end of the upper steering shaft 71 and the upper end of the lower steering shaft 72 as an output shaft are connected via the variable transmission ratio steering device 1.
[0020]
A pinion (not shown) is provided at a lower end of the lower steering shaft 72 via a constant velocity joint (not shown), and the pinion is meshed with a rack 74 in the steering gear box 73. One end of a tie rod 75 is connected to both ends of the rack 74, and a steered wheel 77 is connected to the other end of each tie rod 75 via a knuckle arm 76.
[0021]
Further, the upper steering shaft 71 is provided with a steering angle sensor 78 for detecting the steering angle of the steering wheel 70, and the lower steering shaft 72 is provided with a steering angle sensor 79 for detecting the steering angle of the steered wheels 77. I have. The steering angle of the steering wheel 70 and the steering angle of the steered wheels 77 detected by the steering angle sensor 78 and the steering angle sensor 79 are input to the ECU 80. The vehicle speed output from the vehicle speed sensor 81 that detects the vehicle speed is also input to the ECU 80. The ECU 80 outputs a control signal to the variable transmission ratio steering device 1 to control the variable transmission ratio steering device 1.
[0022]
FIG. 2 is an enlarged view of the variable transmission ratio steering device 1. In this variable transmission ratio steering device 1, a lock mechanism 3, a motor 4, and a wave gear mechanism 5 as a gear mechanism are provided in metal housings 6 to 8 integrally connected to each other. A cable device 2 is provided. The lower end 71a of the upper steering shaft 71 and the upper end 72a of the lower steering shaft 72 are connected to the variable transmission ratio steering device 1.
[0023]
On the upper steering shaft 71 side of the housing 6, a cylindrical fitting portion 6a is formed. The lower end 71a of the upper steering shaft 71 is fitted to the fitting portion 6a via a leaf spring 6b, whereby the housing 6 and the upper steering shaft 71 rotate integrally.
[0024]
The motor 4 has a motor housing 10 in a housing 7. The motor housing 10 includes a metal motor housing body 10a and a metal motor end plate 10b. The motor housing body 10a is formed in a cup shape having a shaft hole 10c in the center. As shown in FIGS. 3 and 4, the motor housing body 10a protrudes radially outward from the outer peripheral surface of the motor housing body 10a. The three protrusions 30 are formed at an angle of θ1 (120 °) in a cross section perpendicular to the axis. A motor end plate 10b is fixed to the upper steering shaft 71 side of the motor housing body 10a so as to close an opening of the motor housing body 10a. The motor 4 is press-fitted into the housing 7 by the housing 7 press-fitting the projections 30. At this time, the flange of the motor housing main body 10a and the flange of the motor end plate 10b abut on the end surface of the housing 7 at a right angle to the axis, and the axial inclination of the motor 4 is corrected.
[0025]
As shown in FIG. 2, a stator 12 is fixed to the inner peripheral surface of the motor housing body 10a, and a rotor 14 driven by the stator 12 is provided in the stator 12. A motor shaft 13 is fixed to the rotor 14, and the motor shaft 13 protrudes axially at both ends of the rotor 14. Further, one end 13a of the motor shaft 13 is supported by a ball bearing 15 provided between the motor shaft 13 and the motor end plate 10b, and the other end 13b of the motor shaft 13 is provided between the motor shaft 13 and a shaft hole 10c of the motor housing body 10a. It is supported by a ball bearing 16. Thus, the motor shaft 13 is coaxially rotatable with respect to the motor housing body 10a and the housings 6 to 8. One end 13a of the motor shaft 13 on the spiral cable device 2 side can be fixed to the housings 6 to 8 by the lock mechanism 3. On the other hand, the other end 13 b of the motor shaft 13 is connected to the wave gear mechanism 5.
[0026]
The wave gear mechanism 5 has a wave generator 17 into which the other end 13b of the motor shaft 13 is fitted and which can rotate integrally with the motor shaft 13. The wave generator 17 includes a cam 17a having an elliptical cross section perpendicular to the axis, and a ball bearing 17b provided on the outer periphery of the cam 17a. The inner ring of the ball bearing 17b is fixed to the outer periphery of the cam 17a, and the outer ring of the ball bearing 17b is elastically deformable via the ball. An annular flexspline 19 that is elastically deformable integrally with the outer ring of the ball bearing 17b is provided on the outer periphery of the wave generator 17. External teeth 19 a are formed on the outer periphery of the flexspline 19. Further, an annular stay circular spline 20 is fixed to the motor 4 side in the housing 7. Inner teeth 20 a of the same number as the outer teeth 19 a of the flexspline 19 are formed on the inner periphery of the stay circular spline 20, whereby the stay circular spline 20 meshes with the flexspline 19. Further, an annular drive circular spline 21 is rotatably supported on the lower steering shaft 72 side of the housing 7 adjacent to the stay circular spline 20 via a bearing metal 7a. Internal teeth 21 a having a smaller number of teeth than the outer teeth 19 a of the flex spline 19 are formed on the inner periphery of the drive circular spline 21, so that the drive circular spline 21 also meshes with the flex spline 19. A protection plate 9 is provided between the motor housing body 10a and the wave gear mechanism 5. The upper end 72a of the lower steering shaft 72 is fixed to the drive circular spline 21.
[0027]
The lock mechanism 3 is supported by a lock holder 24 fixed to the outer periphery of one end 13 a of the motor shaft 13 on the spiral cable device 2 side, and is swingably supported on the housing 6 so as to be able to swing around a pivot axis parallel to the axis. And a lock bar 25 driven by the device. A plurality of lock grooves are formed in the outer periphery of the lock holder 24, and an engagement claw that can engage with the lock groove is formed at one end of the lock bar 25.
[0028]
The spiral cable device 2 is provided on a cylindrical housing 26 held by a vehicle body (not shown), and is provided inside the housing 26 so as to be rotatable relative to the housing 26. And a fixed inner cylinder 27. A flexible flat cable 28 having a plurality of lead wires insulated and coated is provided between the housing 26 and the inner cylinder 27. One end of the flexible flat cable 28 is connected to the inner cylinder 27. It is wound around the inner cylinder 27, and the other end is connected to the housing 26. The lead wire connected to the flexible flat cable 28 and extending from the inner cylinder 27 is connected to the stator 12 of the motor 4 and the like, and the lead wire connected to the flexible flat cable 28 and extending from the housing 26 is not shown in the figure. The battery and the ECU 80 are connected by a connector.
[0029]
In the variable transmission ratio steering device 1 configured as described above, when the driver steers the steering handle 70 in a state where the engaging claw portion of the lock bar 25 is not engaged with the lock groove of the lock holder 24, The steering angle is transmitted to the housings 6 to 8 via the steering shaft 71. The ECU 80 inputs the steering angle from the steering angle sensor 78 and the vehicle speed from the vehicle speed sensor 81. Then, the ECU 80 calculates the target steering angle based on the vehicle speed and the steering angle. A control signal for controlling the motor 4 is output from the ECU 80 to the variable transmission ratio steering device 1 based on the target steering angle.
[0030]
The control signal output from the ECU 80 to the variable transmission ratio steering device 1 is sent to the motor 4 via the spiral cable 28 of the spiral cable device 2. Then, the stator 12 is energized based on this control signal, whereby the rotor 14 is driven to rotate. At this time, since the stator 12 is fixed to the motor housing body 10a and the housing 7, and the rotor 14 is fixed to the motor shaft 13, the motor shaft 13 rotates relative to the housings 6 to 8.
[0031]
Further, since the other end 13b of the motor shaft 13 is fixed to the cam 17a of the wave generator 17, the motor shaft 13 and the cam 17a rotate integrally. The cam 17a has an elliptical shape, and when the cam 17a rotates, the flex spline 19 is elastically deformed to an elliptical shape via the ball bearing 17b. At this time, the outer teeth 19a of the flex spline 19 and the inner teeth 20a, 21a of the stay circular spline 20 and the drive circular spline 21 mesh with each other at both ends of the long axis of the cam 17a. 19a and the internal teeth 20a and 21a are completely separated. Then, the positions where the external teeth 19a of the flexspline 19 mesh with the internal teeth 20a, 21a of the stay circular spline 20 and the drive circular spline 21 sequentially move in the circumferential direction. Here, since the number of the internal teeth 20a of the stay circular spline 20 and the number of the external teeth 19a of the flex spline 19 are the same, relative rotation does not occur between them. On the other hand, since the internal teeth 21a of the drive circular spline 21 have a smaller number of teeth than the external teeth 19a of the flexspline 19, relative rotation occurs between them. That is, when the cam 17a makes one rotation, relative rotation occurs between the internal teeth 21a of the drive circular spline 21 and the external teeth 19a of the flex spline 19 by the difference in the number of teeth. The stay circular spline 20 is fixed inside the housing 7. As a result, the drive circular spline 21 is driven to rotate relative to the housing 7.
[0032]
The rotation of the drive circular spline 21 of the wave gear mechanism 5 causes the lower steering shaft 72 to rotate. Thus, the upper steering shaft 71 and the lower steering shaft 72 are relatively rotated, so that the steering angle of the steering wheel 70 and the steered angle of the steered wheels 77 can be changed.
[0033]
Further, the steering angle of the steered wheel 77 detected by the steered angle sensor 79 is fed back to the ECU 80, so that the steered angle corresponding to the target steering angle can be reliably given to the steered wheel 77.
[0034]
When the driver steers the steering wheel 70 in a state where the engaging claw portion of the lock bar 25 is engaged with the lock groove of the lock holder 24, the steering angles are changed to the housings 6 to 8 via the upper steering shaft 71. And the steering angle is also transmitted to the motor shaft 13. The rotation of the motor shaft 13 is transmitted to the wave gear mechanism 5, where the rotation is reduced and the lower steering shaft 72 is driven to rotate.
[0035]
Thus, in the variable transmission ratio steering apparatus 1, the upper steering shaft 71 and the motor shaft 13 can be locked in an emergency or the like, and the steering is performed in a state where the transmission ratio between the steering angle and the steering angle is changed. The steering angle is transmitted to the system.
[0036]
In the variable transmission ratio steering device 1, a metal motor housing main body 10 a having three convex portions 30 formed on the outer peripheral surface is press-fitted into a metal housing 7. For this reason, each convex part 30 and the housing 7 are press-fitted to each other, and the fastening strength due to the interference is strong in all of the radial, axial, and circumferential directions, and the motor 4 is firmly fixed in the housing 7. For this reason, the motor shaft 13 is hardly shaken, and the wave gear mechanism 5 does not need to receive a load other than the speed change. Therefore, the teeth of the wave gear mechanism 5 are hardly adversely affected, the durability is improved, and abnormal noise due to the eccentric rotation of the motor shaft 13 is hardly generated. Further, compared with the case where the housing 7 is press-fitted over the entire peripheral surface of the motor housing main body 10a, it is not necessary to make the tolerance of the outer periphery of the motor housing main body 10a so strict, and the cost is hardly increased.
[0037]
Therefore, according to the transmission ratio variable steering device 1 of the first embodiment, durability can be improved and noise can be suppressed.
[0038]
Further, in the variable transmission ratio steering device 1, since the wave gear mechanism 5 is employed as the gear mechanism, the number of parts can be reduced, and the size and weight can be reduced. Furthermore, since the wave gear mechanism 5 has a large contact area between the teeth 19a, 20a, and 21a, not only can a high reduction ratio, high efficiency, high accuracy, and high torque be obtained, but also backlash can be extremely reduced.
[0039]
(Embodiment 2)
The variable transmission ratio steering device according to the second embodiment is also used for a steering device as shown in FIG. In the variable transmission ratio steering apparatus according to the second embodiment, as shown in FIG. 5, three convex portions 31a are provided in a circumferential direction protruding radially outward on one axial cross section of the motor housing body 10a. Three convex portions 31b are also provided on the cross section perpendicular to the axis in the circumferential direction to protrude in the radial direction. As shown in FIG. 6, the convex portion 31a and the convex portion 31b form an angle of θ2 (60 °) in a cross section perpendicular to the axis. Other configurations are the same as in the first embodiment.
[0040]
In the variable transmission ratio steering apparatus according to the second embodiment, the motor housing body 10a is provided with a total of six protrusions 31a and 31b arranged in a well-balanced manner. The shaft 13 is less likely to shake. Other functions and effects are the same as those of the first embodiment.
[0041]
(Embodiment 3)
The variable transmission ratio steering device according to the third embodiment is also used for a steering device as shown in FIG. In the variable transmission ratio steering apparatus according to the third embodiment, as shown in FIG. 7, three convex portions 32 are formed on the inner peripheral surface of the small-diameter portion 7 a of the housing 7 in the circumferential direction so as to protrude radially inward. The small diameter portion 7a of the housing 7 is a portion facing the small diameter portion 10d of the motor housing body 10a located on the side of the wave gear mechanism 5 of the motor 4. No protrusion is provided on the motor housing body 10a. Then, the motor 4 is press-fitted into the housing 7 by the small-diameter portion 10 d press-fitting the respective convex portions 32. Other configurations are the same as in the first embodiment.
[0042]
In the variable transmission ratio steering apparatus according to the third embodiment, each projection 32 can be formed when the housing 7 is manufactured. Therefore, there is no need to provide a step of forming a projection on the motor housing body 10a, and the manufacturing process can be simplified. In addition, since each convex portion 32 is provided on the small diameter portion 7a of the housing 7 facing the small diameter portion 10d of the motor housing main body 10a, an operation effect that the initial insertion of the motor 4 is easy is also achieved. Other functions and effects are the same as those of the first embodiment.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a steering device according to a variable transmission ratio steering device according to first to third embodiments.
FIG. 2 is a cross-sectional view of the variable transmission ratio steering device according to the first embodiment.
FIG. 3 is a partially enlarged cross-sectional view of the transmission ratio variable steering device according to the first embodiment.
FIG. 4 is a cross-sectional view of the variable transmission ratio steering device according to the first embodiment, taken along the line IV-IV in FIG. 3;
FIG. 5 is a partially enlarged cross-sectional view of a variable transmission ratio steering device according to a second embodiment.
6 is a cross-sectional view of the variable transmission ratio steering device according to the second embodiment, taken along the line VI-VI in FIG. 5;
FIG. 7 is a partially enlarged cross-sectional view of a variable transmission ratio steering device according to a third embodiment.
FIG. 8 is a sectional view of a conventional transmission ratio variable steering device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Variable transmission ratio steering device 6, 7, 8 ... Housing 70 ... Steering handle 71 ... Input shaft (upper steering shaft)
72 ... Output shaft (lower steering shaft)
4 ... Motor 10 ... Motor housing 10a ... Motor housing main body 10b ... Motor end plate 30, 31a, 31b, 32 ... Protrusion 12 ... Stator 13 ... Motor shaft 14 ... Rotor 5 ... Gear mechanism (wave gear mechanism)

Claims (3)

A metal housing, an input shaft provided integrally rotatable with the housing and transmitting a steering angle of a steering wheel, a motor fixed in the housing and capable of rotating a motor shaft, and rotatable by the housing. An output shaft that is supported and transmits a steering angle to a steering system, and is provided in the housing between the motor shaft and the output shaft, and increases or decreases the rotation angle of the motor shaft and outputs the rotation to the output shaft. And a transmission mechanism that varies the transmission ratio between the steering angle and the steering angle.
The motor includes a metal motor housing main body, a stator fixed to the motor housing main body, a rotor that is driven to rotate by the stator and that protrudes the motor shaft at both ends in the axial direction, and an opening in the motor housing main body. A motor end plate for concealing a portion, and wherein the motor housing body is press-fitted into the housing. 2. The transmission ratio variable steering device according to claim 1, wherein at least three convex portions are formed on an outer peripheral surface of the motor housing body in a radially outward direction and are formed in a circumferential direction. 2. The variable transmission ratio steering device according to claim 1, wherein the inner peripheral surface of the housing has at least three convex portions projecting radially inward and extending in the circumferential direction.

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