JP2010076599A - Transmission ratio variable device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission ratio variable device capable of improving silence. <P>SOLUTION: The transmission ratio variable device 20 is constituted by extending a rotation output shaft 40 downward from a device body 20H, and the rotation output shaft 40 is constituted of first to third constitution shafts 41, 42, 43 coaxially aligned and connected to each other. It is possible to compress and deform the rotation output shaft 40 by pressure when collision of a vehicle 10 by fitting and connecting the second and third constitution shafts 42, 43 to each other free to directly move and to integrally rotate, and it is possible to restrain transmission of vibration downward from the rotation output shaft 40 and to improve silence by fitting the first and second constitution shafts 41, 42 to each other with a play and connecting their peripheral surfaces to each other with vibration-proofing rubber 44. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a transmission that is connected between a steering wheel and a pinion in a vehicle that converts the rotation of the steering wheel into steering of a steered wheel by a rack and pinion mechanism, and that can change a transmission ratio of the rotation between the steering wheel and the pinion. The present invention relates to a variable ratio device.

Conventionally, this type of transmission ratio variable device has a rotary output shaft extending downward from a substantially cylindrical device body, and is connected between a handle and a pinion in a vehicle. In addition, the rotation output shaft is compressed and deformed when the handle is pushed by a collision of the vehicle, and allows the handle to move obliquely downward to secure a wide space on the front side of the driver. (For example, refer to Patent Document 1).
JP 2006-69452 A (FIGS. 2 and 4)

  By the way, in the above-mentioned conventional transmission ratio variable device, the components of the steering system oscillate by the motor built in the device main body, which causes a decrease in the quietness of the vehicle.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a transmission ratio variable device capable of improving silence.

  As a result of performing vibration analysis of the steering system provided with the transmission ratio variable device, the inventor of the present application has found that the lower side of the rotation output shaft than the upper side of the device main body (the handle side) of the transmission ratio variable device. The vibration of was found to be large. This is because the main body of the variable transmission ratio device has a built-in motor and the inertia is relatively large, but the rotation output shaft has a relatively small inertia, so vibration is likely to be transmitted to the rotation output shaft side. Conceivable. In addition, the rack case and column assembly are attached to the vehicle body, and the relay shaft, the device body of the variable transmission ratio device, the rotation output shaft, the intermediate shaft, the pinion, and the rack are connected between the rack case and the column assembly. There is a backlash of each steering system component from the relay shaft to the rack and a backlash between the steering system components. Of the steering system components from the relay shaft to the rack, the rotation output shaft is usually longer than the other steering system components, so the intermediate portion in the longitudinal direction of the rotation output shaft becomes an antinode of vibration. The vibration due to this vibration is transmitted and transmitted to the lower rack and pinion mechanism and the vehicle body, and there is a concern that the quietness in the vehicle may be reduced. Therefore, in order to effectively suppress the vibration caused by the vibration of the rotating shaft, the following invention of the present application has been completed.

  That is, the transmission ratio variable device (20) according to the invention of claim 1 is a vehicle (10) that converts the rotation of the handle (60) into the turning of the steered wheels (11) by the rack and pinion mechanism (12, 15). The transmission ratio variable device (20) connected between the pinion (15) and the handle (60), and the rotation output shaft (40) is moved downward from the device main body (20H) incorporating the motor (22). A transmission ratio variable device that can change the transmission ratio of rotation between the handle (60) and the pinion (15) by rotating the rotation output shaft (40) relative to the apparatus body (20H). 20), the rotary output shaft (40) includes three constituent shafts (41, 42, 43) connected side by side on the same axis, and at least one of the lower two constituent shafts (42, 43). By adopting a cylindrical structure and fitting and coupling these constituent shafts (42, 43) so that they can move linearly and integrally, the rotational output shaft (40) is compressed and deformed by the pressure at the time of collision of the vehicle (10). And at least one of the upper two constituent shafts (41, 42) has a cylindrical structure, the constituent shafts (41, 42) are loosely fitted to each other, and the peripheral surfaces are connected by vibration-proof rubber (44). However, it has characteristics.

  The invention according to claim 2 is the transmission ratio variable device (20) according to claim 1, wherein, of the upper two constituent shafts (41, 42), the inner fitted constituent shaft (42) has a non-circular cross section. While the rotation stopper shaft portion (48) is provided, a stopper hole (47A) having a non-circular cross section is provided in the component shaft (41) fitted on the outside, and usually the rotation stopper shaft portion (47A) is provided in the stopper hole (47A). 48) is loosely fitted in a non-contact state, and when the anti-vibration rubber (44) is twisted by a predetermined amount or more, the rotation stopper shaft portion (48) is brought into contact with the inner surface of the stopper hole (47A) and the anti-vibration rubber ( 44) is characterized by preventing breakage.

  According to a third aspect of the present invention, in the transmission ratio variable device (20) according to the second aspect of the invention, the inner surface of the upper two constituent shafts (41, 42) is projected from the inner surface of the constituent shaft (41). The wall (47) is projected to form a stopper hole (47A) at the center of the inner surface protruding wall (47), while the component shaft (42) fitted inside is passed through the stopper hole (47A). The penetrated portion is used as a rotation stopper shaft portion (48), and an inner surface protruding wall (45F, 49) is projected by a pair of linear motion stoppers (45F, 49) projecting laterally from the component shaft (42) fitted inside. 47) is sandwiched between the constituent shafts (41, 42) in the axial direction so that the axial movement of the constituent shafts (41, 42) is restricted.

  According to a fourth aspect of the present invention, in the transmission ratio variable device (20) according to any one of the first to third aspects, the component shaft (41) fitted on the outside of the upper two component shafts (41, 42). The outer cylinder (46) press-fitted and fixed to the inner surface of the inner cylinder and the inner cylinder (45) press-fitted and fixed to the outer surface of the component shaft (42) fitted inside, the anti-vibration rubber (44) It is characterized by being fixed to the inner surface of the outer cylinder (46) and the outer surface of the inner cylinder (45).

  The invention of claim 5 is characterized in that, in the transmission ratio variable device (20) according to any one of claims 1 to 4, the anti-vibration rubber (44) is butyl rubber.

[Invention of Claim 1]
In the transmission ratio variable device according to claim 1, the lower two constituent shafts of the three constituent shafts included in the rotation output shaft are fitted and coupled so as to be linearly movable and integrally rotatable. As a result, the fitting of these constituent shafts deepens and the rotary output shaft is compressed and deformed. As a result, the steering wheel is allowed to move obliquely downward, and a large space can be secured on the front side of the driver. Moreover, since the two upper constituent shafts of the three constituent shafts included in the rotation output shaft are loosely fitted to each other and the peripheral surfaces of the constituent shafts are connected by vibration-proof rubber, the motor built in the apparatus main body is vibrated. It is possible to suppress the vibration as the source from being transmitted to the coupling portion of the lower two constituent shafts in the constituent shaft and the steering system components below the constituent shaft. As a result, it is possible to improve the quietness of the vehicle by suppressing the oscillation sound caused by the motor built in the apparatus main body as the vibration source and the vibration caused by the vibration of the rotating shaft.

[Invention of claim 2]
In the transmission ratio variable device according to claim 2, when the vibration isolating rubber is twisted by a predetermined amount or more, the rotation stopper portion provided in the other constituent shaft comes into contact with the inner surface of the stopper hole provided in the one constituent shaft, thereby isolating the vibration. Rubber breakage can be prevented.

[Invention of claim 3]
In the transmission ratio variable device according to claim 3, between the two upper constituent shafts connected by the anti-vibration rubber, the inner surface protruding wall and the pair of linear motion stoppers face each other in the axial direction, and the shafts of the constituent shafts Directional deviation can be prevented.

[Invention of claim 4]
In the transmission ratio variable device according to claim 4, vibration isolating rubber is fixed to the inner surface of the outer cylinder and the outer surface of the inner cylinder, and the outer cylinder and the inner cylinder are connected to the inner surfaces of the upper two constituent shafts. By press-fitting and fixing to the outer surface, the two upper constituent shafts can be easily connected with vibration-proof rubber.

[Invention of claim 5]
In the transmission ratio variable device according to the fifth aspect, vibration transmission can be effectively suppressed by using butyl rubber as the vibration isolating rubber.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment according to the invention will be described with reference to FIGS. FIG. 1 shows a vehicle 10 equipped with a transmission ratio variable device 20 according to the present invention. Between the pair of front wheels 11, 11 in the vehicle 10, a rack 12 (“tooth portion” of the rack 12 is not shown) is passed, and both ends of the rack 12 are connected via tie rods 13, 13. It is connected to the front wheels 11. The rack 12 is covered with a cylindrical rack case 12C, and the rack case 12C is fixed to the vehicle body. The rack 12 is engaged with a pinion 15 (the “tooth portion” of the pinion 15 is not shown), and the pinion 15 is rotatably supported by the rack case 12C.

  An intermediate shaft 18 is connected to the upper end of the pinion 15. The intermediate shaft 18 has a structure in which a pair of cylindrical bodies 18A and 18B are connected by a universal joint mechanism 18J. Then, serrations (a plurality of longitudinal bars extending in the axial direction) are formed on the inner surface of one cylindrical body 18A and the outer surface of the upper end portion of the pinion 15, and the pinions 15 are fitted into the cylindrical body 18A so that the serrations are formed. The pinion 15 and the intermediate shaft 18 are connected so as to be integrally rotatable.

  A transmission ratio variable device 20 is connected to the upper end portion of the intermediate shaft 18, and a handle 60 is connected to the upper end portion of the transmission ratio variable device 20 via the relay shaft 19. Specifically, a steering shaft 60S extends from the back surface of the center portion of the handle 60, and a column assembly 61 is provided so as to surround the steering shaft 60S. The column assembly 61 is attached to the vehicle main body via a tilt mechanism (not shown) provided in the vehicle main body, and rotatably supports the steering shaft 60S. The tilt angle of the handle 60 can be adjusted by operating the tilt mechanism. Further, the column cover 62 includes a wiper operation lever 63 and a winker operation lever 64 projecting laterally, and includes a steering sensor (steering angle sensor) (not shown) on the inner side.

  The relay shaft 19 has a structure in which the lower shaft 19A and the upper shaft 19B are connected by a universal joint mechanism 19J. The steering shaft 60S and the upper shaft 19B are connected so as to be integrally rotatable by serration, similarly to the connection between the pinion 15 and the intermediate shaft 18 described above. The lower shaft 19A is connected to a cylindrical shaft 25C (see FIG. 3) provided at the upper end of the transmission ratio variable device 20 so as to be integrally rotatable by serration.

  Now, the entire transmission ratio variable device 20 is shown in FIG. 2, and includes a columnar device body 20H and a rotation output shaft 40 extending downward from the lower end of the device body 20H. As shown in FIG. 3, the apparatus main body 20 </ b> H has a motor 22 disposed above the differential reduction gear 21 and accommodates the reduction gear 21 and the motor 22 in a common cylindrical sleeve 23. Prepared. The reduction gear 21 is a differential reduction gear, and includes a wave gear mechanism. The reduction gear 21 includes a rotational torque input portion 21A at the center thereof, and a ring-shaped member disposed at the outer edge of the lower end is a rotational torque output portion. 21B. In addition, a ring-shaped member arranged at the outer edge of the upper end of the speed reducer 21 is fixed to the assembly sleeve 23.

  A stator 22S of the motor 22 has a cylindrical shape and is fixed to the ash sleeve 23, and a rotor shaft 22R protruding from the lower end surface of the motor 22 is connected to a rotational torque input portion 21A of the speed reducer 21 so as to be integrally rotatable. The rotor shaft 22R also protrudes from the upper end surface of the stator 22S, and a lock ring 31 is fitted and fixed to the outside of the protruding portion. For example, in an emergency, a hook (not shown) provided at the upper end of the stator 22S engages with the lock ring 31 to lock the rotor shaft 22R.

  A rotational position detector 24 is provided at the upper end of the motor 22. The rotational position detector 24 detects the rotational position of the rotor 22R relative to the stator 22S. The rotational position detector 24 includes a magnet 24A that rotates integrally with the rotor 22R, and a Hall element 24B that is fixed to the stator 22S.

  A cylindrical shaft 25C protrudes from the upper end surface of the assy sleeve 23, and a donut-shaped cable case 26 is assembled to the outside of the cylindrical shaft 25C. The cable of the motor 22 is connected to the steering control device 65 (see FIG. 1) via a spiral cable 27 housed in the cable case 26.

  As shown in FIG. 2, the rotation output shaft 40 is formed by assembling first, second, and third constituent shafts 41, 42, and 43. As shown in FIG. 3, the first component shaft 41 is cylindrically fixed to the upper end portion of the first component shaft 41 so as to be integrally rotatable (for example, welded) with the disk 40Z being centered. ing. The disc 40Z is addressed to the lower end surface of the speed reducer 21, and the outer edge portion of the disc 40Z and the rotational torque output portion 21B of the speed reducer 21 are coupled so as to be integrally rotatable. And the 1st structure shaft 41 is extended in the outer lower side of the apparatus main body 20H through the through-hole formed in the center of the lower end wall 23Z of the assi sleeve 23. A through hole is formed at the center of the disc 40Z, and the upper end portion of the first component shaft 41 is opened upward through the through hole of the disc 40Z.

  As shown in FIG. 4, an inner surface protruding wall 47 protrudes inward from the position near the lower end of the inner surface of the first constituting shaft 41. A stopper hole 47 </ b> A is formed through the central portion of the inner surface protruding wall 47. As shown in FIG. 5, the inner surface of the stopper hole 47A forms flat surfaces 47B and 47B at two symmetrical positions in the round hole, and a pair of arcuate surfaces 47C and 47C between both ends of the flat surfaces 47B and 47B. The shape is left. A U-shaped groove 47D extending in the axial direction of the first component shaft 41 is formed at the center in the width direction of each flat surface 47B.

  As shown in FIG. 2, the second component shaft 42 has a rod shape with a circular cross section as a whole, and includes a rotation stopper shaft portion 48 at the upper end portion. The rotation stopper shaft portion 48 protrudes laterally from the outer peripheral surface of the entire second component shaft 42, and its cross-sectional shape is a non-circular shape that is loosely fitted into the stopper hole 47A as shown in FIG. Yes. Specifically, it has a structure in which two symmetrical positions in a disk projecting laterally from the first component shaft 41 are cut flat. Normally, the rotation stopper shaft portion 48 is loosely fitted in the stopper hole 47A in a non-contact state. Further, as shown in FIG. 4, the lower end portion of the first constituent shaft 41 from the inner surface protruding wall 47 and the lower portion of the second constituent shaft 42 below the rotation stopper shaft portion 48 are also loosely fitted. It has become. Then, a rubber coupling 50 connects the peripheral surfaces of the lower end portion of the first constituent shaft 41 from the inner surface protruding wall 47 and the lower portion of the second constituent shaft 42 from the rotation stopper shaft portion 48. Yes.

  The rubber coupling 50 includes an inner cylinder 45, an outer cylinder 46 disposed on the concentric circle of the inner cylinder 45, and an outer peripheral surface of the inner cylinder 45 and an inner peripheral surface of the outer cylinder 46. It consists of vibration-proof rubber 44 fixed by vulcanization. Specifically, the lower end surfaces of the inner cylinder body 45 and the outer cylinder body 46 are flush with each other. Further, the inner cylinder 45 extends longer than the outer cylinder 46, and a stopper flange 45F (corresponding to the “linear motion stopper” of the present invention) protrudes laterally from the upper end of the inner cylinder 45. Yes. Further, in a state where the inner cylinder body 45 and the outer cylinder body 46 are arranged concentrically, the molten butyl rubber is poured into the gap between the inner cylinder body 45 and the outer cylinder body 46 to be cooled, so that the inner cylinder The peripheral surface of the body 45 and the outer cylindrical body 46 is connected by a vibration isolating rubber 44. The inner cylinder 45 is press-fitted and fixed to the outside of the second component shaft 42, while the outer cylinder 46 is press-fitted and fixed to the inside of the first component shaft 41, so that the first component shaft 41 and the second component The shaft 42 is connected via a vibration-proof rubber 44.

  The assembly procedure is described in detail as follows. First, the inner cylinder 45 is inserted upward from the lower end portion of the second component shaft 42 and is press-fitted and fixed below the rotation stopper shaft portion 48. Here, as for the 2nd structure shaft 42, the outer diameter below the part to which the inner cylinder 45 is press-fitted and fixed is slightly small (not shown). As a result, the inner cylinder 45 can be easily inserted with a gap fitted to the vicinity of the press-fitting position on the second component shaft 42. Then, after the inner cylinder 45 is press-fitted into the second constituent shaft 42, the outer cylinder 46 is press-fitted into the first constituent shaft 41. As a result, the first and second constituent shafts 41 and 42 are connected by the rubber coupling 50.

  The anti-vibration rubber 44 may be directly fixed to the peripheral surfaces of the first and second constituent shafts 41 and 42 with an adhesive. However, as in the present embodiment, the anti-vibration rubber 44 is fixed between the inner cylinder 45 and the outer cylinder 46, and the inner cylinder 45 and the outer cylinder 46 are first and second configurations. If it is configured to press-fit into the shafts 41 and 42, the component shafts 41 and 42 can be connected to each other by placing the anti-vibration rubber 44 at an accurate position without waiting for the adhesive to solidify. Moreover, vibration transmission can be effectively suppressed by making the vibration-proof rubber 44 butyl rubber.

  Next, in a state where the constituent shafts 41 and 42 are connected to each other, a circular stopper plate 49 (see FIG. 4 corresponding to the “linear motion stopper” of the present invention) is opened from the upper end opening (see FIG. 3) of the second constituent shaft 42. insert. And the circular stopper board 49 is fixed to the upper end surface of the 2nd structure shaft 42 with the external screw N1. For this purpose, a through hole for inserting the male screw N1 is formed at the center of the circular stopper plate 49, and a female screw is formed at the center of the upper end surface of the second component shaft 42. The circular stopper plate 49 fixed to the second constituent shaft 42 projects laterally from the second constituent shaft 42, and the second constituent shaft 42 and the stopper flange 45F face each other across the inner surface protruding wall 47 in the axial direction. It will be in the state.

  As shown in FIG. 2, the third component shaft 43 has a cylindrical shape, and serrations are formed on the inner surface thereof. Further, serrations are formed below the portion of the second constituent shaft 42 where the inner cylinder 45 is press-fitted and fixed. And the lower end part of the part in which serration was formed among the 2nd composition shafts 42 is fitted inside the upper end part of the 3rd composition shaft 43, and serrations are engaged. Further, a female screw hole 43A is formed through the side of the third component shaft 43 near the upper end, and the second and second screw holes 43A are frictionally locked by the set screw 43B screwed into the female screw hole 43A. The third constituent shafts 42 and 43 are temporarily fixed in the axial direction. When an axial force is applied to the second and third constituent shafts 42 and 43, the fitting between the second and third constituent shafts 42 and 43 deepens and the rotation output shaft 40 is compressed and deformed.

  The steering control device 65 (see FIG. 1) captures the steering angle of the handle 60 from the steering sensor (steering angle sensor) built in the column cover 62 and the detection result of the vehicle speed sensor 66 provided in the vehicle 10. Then, the steering control device 65 feedback-controls the rotational position of the motor 22 so that the rotation output shaft 40 is rotationally driven by the motor 22 with respect to the device main body 20H by the rotational angle corresponding to the steering angle and the vehicle speed. .

  This completes the description of the configuration of the transmission ratio variable device 20 of the present embodiment. Next, the function and effect of the transmission ratio variable device 20 of this embodiment will be described. When the ignition switch of the vehicle 10 is turned on, the steering control device 65 is energized. During low-speed traveling, the rotation output shaft 40 of the transmission ratio variable device 20 is rotationally driven so that the rotation angle of the pinion 15 with respect to the steering angle of the handle 60 becomes relatively large. Thereby, it becomes possible to steer the steered wheels 11 with a slight operation of the handle 60, and for example, parallel parking and garage parking can be easily performed. On the other hand, during high-speed traveling, the rotation output shaft 40 is rotationally driven so that the rotation angle of the pinion 15 with respect to the steering angle of the handle 60 becomes relatively small. As a result, it is possible to prevent a situation in which the vehicle 10 spins due to the sudden steering wheel turning at a high speed.

  Further, when the vehicle 10 collides and is pushed from the pinion 15 side or the handle 60 is pushed, the fitting of the second and third constituent shafts 42 and 43 in the transmission ratio variable device 20 is deepened and the rotation output is increased. The shaft 40 is compressed and deformed. As a result, the handle 60, the transmission ratio variable device 20 and the like can be prevented from moving to the driver side, and the handle 60 is allowed to move obliquely downward, so that a wide space can be secured on the front side of the driver. The driver can easily escape from the vehicle 10.

  Further, the steering system components connected between the rack case 12C attached to the main body of the vehicle 10 and the column assembly 61, that is, the relay shaft 19, the device main body 20H of the transmission ratio variable device 20, the rotation output shaft 40, the rack and According to the transmission ratio variable device 20 of the present embodiment, even if there is play in each steering system component of the pinion 15 of the pinion mechanism and the rack 12 or there is play between the steering system components. By reducing the vibration of the rotation output shaft 40 that is the rotation output portion, the vibration of the entire steering system can be effectively reduced. Specifically, in the transmission ratio variable device 20 of the present embodiment, the upper two first and second constituent shafts 41 among the first to third constituent shafts 41, 42, 43 included in the rotation output shaft 40. , 42 are loosely fitted to each other and the peripheral surfaces of the constituent shafts 41, 42 are connected by a vibration isolating rubber 44, so that vibrations using the motor 22 incorporated in the apparatus body 20H as a vibration source are absorbed by the vibration isolating rubber 44. Thus, the vibration of the anti-vibration rubber 44 is suppressed. As a result, the transmission of vibrations to the joint portion of the lower two constituent shafts 42 and 43 of the rotary output shaft 40 and the pinion 15 below it is suppressed, effectively reducing the vibration of the entire steering system. can do.

  As described above, according to the transmission ratio variable device 20 of the present embodiment, it is possible to improve the quietness of the vehicle 10 by suppressing the oscillating sound using the motor 22 built in the device main body 20H as the vibration source. Further, when the vibration isolating rubber 44 is twisted by a predetermined amount or more, the rotation stopper shaft portion 48 provided on the second constituent shaft 42 comes into contact with the inner surface of the stopper hole 47A provided on the first constituent shaft 41, and the vibration isolating rubber 44 is provided. The shafts 41 and 42 are not completely separated from each other even if the vibration isolating rubber 44 is broken. Furthermore, the inner surface protruding wall 47, the stopper flange 45F, and the circular stopper plate 49 are opposed in the axial direction between the first and second constituent shafts 41, 42 connected by the vibration isolating rubber 44. The axial displacement between the first and second constituent shafts 41 and 42 can be prevented.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

  (1) Of the first to third constituent shafts 41, 42, 43 constituting the rotation output shaft 40, the first and third constituent shafts 41, 42 at both ends have a cylindrical structure, and the center second Although the component shaft 42 has a solid structure, all the component shafts may have a cylindrical structure, or only the central component shaft may have a cylindrical structure, and the component shafts at both ends may have a solid structure.

  (2) Although the anti-vibration rubber 44 of the above embodiment has a cylindrical structure, the anti-vibration rubber may be distributed in the circumferential direction of the rotation output shaft.

  (3) The transmission ratio variable device 20 of the above embodiment includes the wave gear mechanism. However, instead of the wave gear mechanism, the transmission ratio variable device 20 may have a structure including another mechanism such as a Coriolis movement gear mechanism.

The perspective view of the transmission ratio variable apparatus which concerns on one Embodiment of this invention. Partial sectional view of the transmission ratio variable device Side sectional view of the device body in the transmission ratio variable device Side sectional view of the rotary output shaft in the transmission ratio variable device 4 is a cross-sectional view of the rotary output shaft taken along the line AA in FIG. 4 (line AA in FIG. 4).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle 11 Steering wheel 12 Rack 15 Pinion 20 Transmission ratio variable apparatus 20H Apparatus main body 22 Motor 40 Rotation output shaft 41, 42, 43 Structure shaft 44 Anti-vibration rubber 45 Inner cylinder 45F Stopper flange (linear motion stopper)
46 Outer cylinder 47 Internal protrusion wall 47A Stopper hole 48 Rotary stopper shaft 49 Circular stopper plate (linear stopper)
60 handle

Claims (5)

A transmission ratio variable device connected between the pinion and the steering wheel of a vehicle that converts the rotation of the steering wheel into a steered wheel by a rack-and-pinion mechanism. In the transmission ratio variable device that can change the transmission ratio of rotation between the handle and the pinion by rotationally driving the rotation output shaft with respect to the apparatus main body,
The rotary output shaft comprises three component shafts connected side by side on the same axis,
At least one of the lower two constituent shafts is formed into a cylindrical structure, and the constituent shafts are fitted and coupled so as to be capable of linear movement and integral rotation. Compressible deformation,
A transmission ratio variable device characterized in that at least one of the two upper constituent shafts has a cylindrical structure, the constituent shafts are loosely fitted to each other, and the peripheral surfaces are connected by vibration-proof rubber.   A rotation stopper shaft portion having a non-circular cross section is provided on the component shaft fitted inside on the upper two of the component shafts, while a stopper hole having a non-circular cross section is provided on the component shaft fitted on the outside. Normally, the rotary stopper shaft portion is loosely fitted in the stopper hole in a non-contact state, and when the anti-vibration rubber is twisted by a predetermined amount or more, the rotation stopper shaft portion is brought into contact with the inner surface of the stopper hole. The transmission ratio variable device according to claim 1, wherein breakage of the anti-vibration rubber is prevented.   An inner protruding wall is projected from the inner surface of the component shaft that is fitted to the outside of the upper two component shafts, and the stopper hole is formed at the center of the inner surface protruding wall, while the fitting shaft is fitted to the inner side. The component shaft is penetrated through the stopper hole, and the penetrating portion is used as the rotation stopper shaft portion. Further, the pair of linear motion stoppers projecting sideways from the component shaft fitted inside The transmission ratio variable device according to claim 2, wherein movement of the constituent shafts in the axial direction is restricted by sandwiching an inner surface protruding wall in the axial direction.   An outer cylinder body that is press-fitted and fixed to the inner surface of the constituent shaft that is fitted to the outside of the two upper constituent shafts, and an inner cylinder body that is press-fitted and fixed to the outer surface of the constituent shaft that is fitted to the inner side. 4. The transmission ratio variable device according to claim 1, wherein the anti-vibration rubber is fixed to an inner surface of the outer cylindrical body and an outer surface of the inner cylindrical body.   The transmission ratio variable device according to any one of claims 1 to 4, wherein the anti-vibration rubber is butyl rubber.

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