JP2007210544A - Transmission ratio adjustable device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transmission ratio adjustable device capable of stably maintaining a torque limiter function of a lock device when oil leaks in a hydraulic valve device. <P>SOLUTION: A working oil flow preventing member 50 is formed into an approximate disc-like shape having a through hole 51 at a center, and an outside diameter R thereof is set larger than an outside diameter r1 of a lock holder 23. Then, the through hole 51 is pressure fit in a motor shaft 15, so as to be fixed on the hydraulic valve device side beyond the lock holder 23. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a transmission ratio variable device.

  Conventionally, there is a transmission ratio variable device that uses a differential mechanism to add rotation based on motor drive to rotation of an input shaft based on a steering operation and transmit the rotation to an output shaft (see, for example, Patent Document 1). In such a transmission ratio variable device, in order to prevent free rotation between the input shaft and the output shaft when the IG is off or when an abnormality occurs, the rotation is restricted by restraining a lock holder provided on the motor shaft. Some have a locking device (see, for example, Patent Document 2).

As shown in FIG. 7, in the lock device 90 as described above, a torque limit ring 93 is interposed between the motor shaft 91 and the lock holder 92. As shown in FIG. 8, the torque limit ring 93 is formed by bending a long metal plate into a substantially annular shape, and is fitted to the motor shaft 91 together with the lock holder 92 so as to be compressed inward in the radial direction. Is done. Then, the relative rotation between the motor shaft 91 and the lock holder 92 is restricted based on the frictional resistance between the inner peripheral surface 93a and the motor shaft 91, and when there is a torque input above a certain level, the inner peripheral surface 93a. By being a sliding surface, the relative rotation is allowed, that is, it functions as a torque limiter.
JP 2004-175336 A Japanese Patent Laid-Open No. 2003-320943

  By the way, normally, a lubricant (grease) X is applied to the inner periphery of the torque limit ring 93 in order to stabilize the frictional resistance. And the inside of the convex part (wave) 94 bulging and formed on the peripheral surface of the torque limit ring 93 becomes such an “oil reservoir” of the lubricant X, so that the stable lubricating action is maintained. It has become.

  However, like the transmission ratio variable device shown in Patent Document 1 (FIG. 8), it is incorporated in a hydraulic power steering device, and an input shaft is connected to a steering shaft via a hydraulic valve device, that is, a hydraulic valve. In the configuration arranged below the device, when oil leakage occurs in the hydraulic valve device, the leaked hydraulic oil (fluid) flows out to the transmission ratio variable device side. For this reason, when such hydraulic oil adheres to the locking device, the lubricant applied to the inner periphery of the torque limit ring may flow down when it flows down the motor shaft, resulting in poor lubrication due to this. Therefore, there is a problem that the relative rotational torque between the motor shaft and the lock holder cannot be stably maintained.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to stably maintain the torque limiter function of the lock device even when oil leakage occurs in the hydraulic valve device. It is to provide a transmission ratio variable device.

  In order to solve the above-mentioned problems, the invention according to claim 1 is provided on the motor shaft, and a differential mechanism that adds the rotation based on the motor drive to the rotation of the input shaft based on the steering operation and transmits the rotation to the output shaft. A lock device that restricts rotation of the motor shaft by restraining the lock holder, and the motor shaft is disposed coaxially with the input shaft, and a frictional resistance is provided between the motor shaft and the lock holder. And a torque limit ring for restricting and allowing relative rotation between the motor shaft and the lock holder based on the transmission shaft, and the input shaft is a transmission ratio variable device connected to the steering shaft via a hydraulic valve device. The hydraulic fluid flow formed on the motor shaft or the input shaft between the hydraulic valve device and the lock holder is formed with a diameter larger than that of the torque limit ring. Providing the preventing member, and the gist.

  According to the above configuration, the hydraulic oil leaked from the hydraulic valve device travels down from the peripheral edge of the hydraulic oil inflow prevention member along the upper surface of the hydraulic oil inflow prevention member. Thereby, hydraulic fluid can be prevented from flowing through the motor shaft and directly into the fixing portion between the lock holder where the torque limit ring is arranged. As a result, the lubricant can be prevented from flowing out from the inner periphery of the torque limit ring due to the leaked hydraulic oil, and the relative rotational torque can be stably maintained.

The gist of the invention described in claim 2 is that the hydraulic oil inflow prevention member is formed to have a larger diameter than the lock holder.
The gist of the invention described in claim 3 is that a recess corresponding to the outer diameter of the hydraulic oil inflow prevention member is formed in the upper surface periphery of the lock holder.

According to each said structure, the path | route in which hydraulic fluid flows along the upper surface of a lock holder and flows in into a fixing | fixed part can also be interrupted | blocked.
The gist of the invention according to claim 4 is that the hydraulic oil inflow prevention member includes a sneaking suppression means for suppressing sneaking of the hydraulic oil to the lower surface of the hydraulic oil inflow prevention member.

The gist of the invention described in claim 5 is that the wraparound suppression means is a protrusion provided on a peripheral edge of the hydraulic oil inflow prevention member and protruding downward in the axial direction.
According to the structure of the said Claim 4, it can prevent that hydraulic fluid wraps around the lower surface of a hydraulic fluid inflow prevention member, dripping on the upper surface of a lock holder, or being transmitted to a motor shaft. This can be easily realized by configuring the hydraulic oil so as to flow down the axial direction downward along the protrusions.

The gist of the invention described in claim 6 is that the protrusion extends below the upper surface of the lock holder.
According to the said structure, it can prevent that the hydraulic fluid which flowed down from the protrusion splashes on the upper surface of a lock holder.

The gist of the invention according to claim 7 is that the hydraulic oil inflow prevention member includes a guiding means for guiding the hydraulic oil to the protrusion.
According to the above configuration, the working oil can be more effectively prevented from entering the lower surface of the working oil inflow prevention member.

  According to the eighth aspect of the present invention, the rotation of the input shaft based on the steering operation is added to the rotation based on the motor drive and transmitted to the output shaft, and the lock holder provided on the motor shaft is restrained. A lock device for restricting rotation of the motor shaft, the motor shaft being arranged coaxially with the input shaft, and between the motor shaft and the lock holder based on frictional resistance, the motor shaft and the lock holder A torque limit ring that restricts and allows relative rotation with the input shaft is a transmission ratio variable device that is connected to a steering shaft via a hydraulic valve device, and stores a lubricant And the torque limit ring is immersed in the stored lubricant.

  According to the above configuration, even when the hydraulic oil leaked from the hydraulic valve device flows into the fixed portion, the lubricant is not washed away by the hydraulic oil. Thereby, generation | occurrence | production of poor lubrication can be prevented and the relative rotational torque can be maintained stably.

  According to the present invention, it is possible to provide a transmission ratio variable device capable of stably maintaining the torque limiter function of the lock device even when oil leakage occurs in the hydraulic valve device.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the transmission ratio variable device 1 according to this embodiment includes a steering wheel housed in a steering gear box 5 together with a rack and pinion mechanism 2 and a hydraulic valve device 4 constituting a hydraulic power steering device 3. This is a gear-integrated transmission ratio variable device.

  More specifically, the steering gear box 5 includes a lower housing 6 that houses the rack and pinion mechanism 2, a middle housing 7 that houses the transmission ratio variable device 1, and an upper housing 8 that forms part of the hydraulic valve device 4. Thus, the middle housing 7 and the upper housing 8 are formed in a substantially cylindrical shape. One end of the middle housing 7 is fixed above the lower housing 6 (upper side in the figure), and an upper housing 8 is fixed to the other end so as to be coaxial with the middle housing 7.

  In the lower housing 6, the pinion shaft 9 constituting the rack and pinion mechanism 2 is rotatably supported such that one end of the pinion shaft 9 protrudes into the middle housing 7, and the rack shaft 10 is linked to the pinion shaft 9. In this manner, the bearing is slidable in the axial direction by a plain bearing (not shown). The rack shaft 10 is engaged with the pinion shaft 9 by being pressed by the rack guide 11.

  The transmission ratio variable device 1 includes a middle shaft 12 serving as an input shaft, a motor 13 serving as a driving source, and a difference transmitted to the pinion shaft 9 serving as an output shaft by adding rotation based on motor driving to the rotation of the middle shaft 12. And a wave gear device 14 as a moving mechanism.

  A brushless motor having a hollow motor shaft 15 is adopted as the motor 13, and the motor shaft 15 is rotatably supported inside a stator 16 provided on the inner periphery of the middle housing 7. The wave gear device 14 includes a pair of circular splines 17 and 18 arranged coaxially, a flex spline 19 meshed with each spline, and a wave generator that rotates the meshing portion inside the flex spline 19. The wave gear device 14 is disposed closer to the lower housing 6 than the motor 13 (lower side in the figure). The middle shaft 12 is connected to the circular spline 17 on the lower housing 6 side through the connecting member 21a by being inserted into the motor shaft 15 connected to the wave generator 20, and the circular spline 18 on the motor 13 side is The pinion shaft 9 is connected via a connecting member 21b.

  That is, the rotation of the middle shaft 12 constituting the input shaft is transmitted from the circular spline 17 connected to the middle shaft 12 to the pinion shaft 9 constituting the output shaft from the circular spline 18 via the flex spline 19. Further, the wave generator 20 is driven by the motor 13 so that the bent flex spline 19 has a substantially elliptical shape, that is, the meshing portion with both the circular splines 17 and 18 rotates, and both the circulars are based on the number of teeth difference. As the splines 17 and 18 rotate relative to each other, rotation based on motor driving is transmitted to the pinion shaft 9. As a result, the rotation based on the motor drive is added to the rotation of the middle shaft 12 based on the steering operation and transmitted to the pinion shaft 19.

  The variable transmission ratio device 1 also includes a lock device 22 that prevents free rotation between the middle shaft 12 constituting the input shaft and the pinion shaft 9 constituting the output shaft by restricting the rotation of the motor shaft 15. I have. Specifically, as shown in FIG. 2, the lock device 22 includes a lock holder 23 that is provided on the motor shaft 15 and rotates together with the motor shaft 15, a lock arm 24 that can restrain the lock holder 23, and the lock And a solenoid 25 for driving the arm 24.

  The lock holder 23 is formed in a substantially annular shape, and a plurality of engaging grooves 26 extending in the thickness direction (axial direction) are recessed in the outer periphery thereof. In the present embodiment, the lock holder 23 is fitted in the vicinity of the end of the motor shaft 15 on the upper housing 8 side via a torque limit ring 27 (see FIG. 7). A lubricant (grease) X is applied to the inner periphery of the torque limit ring 27 in order to stabilize the frictional resistance.

  On the other hand, the lock arm 24 is pivotally supported on the outer side in the radial direction of the lock holder 23 by a support shaft 28 provided on the middle housing 7 side. One end of the lock arm 24 is provided with an engaging claw 29 protruding toward the outer peripheral surface of the lock holder 23, and the other end is connected to a plunger 25 a of a solenoid 25. The lock arm 24 is urged by the elastic force of the coil spring 30 so that the end portion on the engagement claw 29 side rotates toward the lock holder 23 side.

  In other words, the lock arm 24 is arranged so that its engaging claw 29 is arranged on the radially outer side of the lock holder 23 against the elastic force of the coil spring 30 by energizing the solenoid 25 during normal time (when not locked). It is driven to. On the other hand, at the time of locking, the energization to the solenoid 25 is stopped, so that the lock arm 24 rotates its end portion on the engagement claw 29 side toward the lock holder 23 side, and the engagement claw 29 moves to the lock holder. By engaging with the engagement groove 26 on the 23 side, the lock holder 23 is restrained relative to the middle housing 7 so as not to rotate relative to the middle housing 7. Based on the frictional resistance between the torque limit ring 27 and the motor shaft 15, the relative rotation between the motor shaft 15 and the lock holder 23 is restricted, and when there is an input torque exceeding a predetermined value, the relative rotation is reduced. It is configured to allow.

  The hydraulic valve device 4 of the present embodiment is a known rotary valve device, and a sleeve 31 and a hollow upper shaft 32 formed in a substantially cylindrical shape and a torsion bar 33 are concentric in the upper housing 8. It is housed in a shape. Specifically, one end of the sleeve 31 (the lower side in the drawing, the end on the middle housing 7 side) is connected to the middle shaft 12, and one end of the upper shaft 32 protrudes outside the upper housing 8. In this state, it is rotatably supported and accommodated in the cylinder of the sleeve 31. Further, the torsion bar 33 is accommodated in the cylinder of the upper shaft 32, one end of which is connected to the pinion shaft 9, and the other end is connected to the upper shaft 32 (the outer end portion thereof). A steering shaft 34 that rotates in response to a steering operation is connected to an outer end of the upper shaft 32 that protrudes to the outside of the upper housing 8.

  The inside of the cylinder of the upper housing 8 is liquid-tightly sealed by seal members 35 and 36 interposed between the upper housing 8 and the upper shaft 32 and the middle shaft 12, respectively. A plurality of ports connected to the hydraulic circuit 37 of the device 3 are formed. Specifically, the first port 38a and the second port 38b are connected to the hydraulic pump 40 and the oil tank 41, respectively, and the third port 38c and the fourth port 38d are respectively connected to the power provided in the rack shaft 10. The first and second pressure chambers 43 and 44 of the cylinder 42 are connected. The sleeve 31 and the upper shaft 32 are formed with a plurality of oil passages 45 and 46 that respectively penetrate the cylindrical wall in the radial direction. The oil passages 45 and 46 are configured so that the circumferential positions of the sleeve 31 and the upper shaft 32 change based on the torsion of the torsion bar 33 according to the input torque, whereby the first port 38a and the third port 38c. And the flow path area ratio between the first port 38a and the fourth port 38d is changed.

  That is, in the cylinder of the upper housing 8, a valve chamber is formed at a portion defined by both seal members 35 and 36, and a valve body is formed by the sleeve 31 and the upper shaft 32 disposed in the valve chamber. ing. Note that the hydraulic oil flowing in from the first port 38a is returned to the hydraulic pump 40 via the oil tank 41 from the second port 38b. Each of the oil passages 45 and 46 is configured so that the hydraulic pressure applied to the third port 38c and the fourth port 38d is equal in a state where the torsion bar 33 is not twisted, and based on the twist of the torsion bar 33. As the circumferential position of the upper shaft 32 changes, a hydraulic pressure difference is generated between the third port 38c and the fourth port 38d. In the power steering device 3, the power cylinder 42 is connected to the rack shaft 10 based on the pressure difference between the third port 38c and the fourth port 38d, that is, the pressure difference between the first and second pressure chambers 43 and 44. By pressing in the axial direction, an assist force is applied to the steering system.

(Working oil inflow prevention structure)
As described above, in the configuration in which the transmission ratio variable device 1 is disposed below the hydraulic valve device 4 as in the present embodiment (lower side in FIG. 1), when oil leakage occurs in the hydraulic valve device 4, The leaked hydraulic oil flows out to the transmission ratio variable device 1 side. Then, when the hydraulic oil flows down the motor shaft 15, the lubricant X applied to the inner periphery of the torque limit ring 27 may flow down.

  In view of this point, in the transmission ratio variable device 1 according to the present embodiment, a fixing portion between the motor shaft 15 and the lock holder 23 in which the torque limit ring 27 is disposed between the hydraulic valve device 4 and the lock holder 23. A hydraulic oil inflow prevention member 50 is provided to prevent the hydraulic oil from flowing into 49.

  As shown in FIG. 3, the hydraulic oil inflow prevention member 50 is formed in a substantially disk shape having a through hole 51 in the center, and the outer diameter R is set larger than the outer diameter r <b> 1 of the lock holder 23. Yes. Then, the through-hole 51 is press-fitted into the motor shaft 15 so that the end of the motor shaft 15 on the upper housing 8 side is fixed to the hydraulic valve device 4 side (upper side in the figure) from the lock holder 23. ing. Further, at the periphery of the hydraulic oil inflow prevention member 50, a protrusion 52 as a sneak suppression means formed in an annular shape (cylindrical shape) along the periphery is directed downward in the axial direction (lower side in the figure). Projected. And the front-end | tip of this protrusion 52 is extended below the upper surface 23a of the lock holder 23. As shown in FIG.

As described above, according to the present embodiment, the following operations and effects can be obtained.
(1) By providing the hydraulic oil inflow prevention member 50 on the motor shaft 15 closer to the hydraulic valve device 4 than the lock holder 23, the hydraulic oil leaked from the hydraulic valve device 4 can be removed from the upper surface 50 a of the hydraulic oil inflow prevention member 50. It travels down from its periphery. Thereby, hydraulic oil can be prevented from flowing through the motor shaft 15 and directly into the fixing portion 49 with the lock holder 23. And by making the outer diameter R larger than the outer diameter r1 of the lock holder 23, the path flowing into the fixing portion 49 via the upper surface 23a of the lock holder 23 can be blocked. As a result, it is possible to prevent the lubricant X from flowing out from the inner periphery of the torque limit ring 27 due to the leaked hydraulic oil, and to stably maintain the relative rotational torque.

  (2) By providing the protrusion 52 at the periphery of the hydraulic oil inflow prevention member 50, the hydraulic oil attached to the upper surface 50 a of the hydraulic oil inflow prevention member 50 flows down the axial direction and flows down the axial direction. Thereby, it is possible to prevent the hydraulic oil from flowing around the lower surface 50 b of the hydraulic oil inflow prevention member 50 and dropping on the upper surface 23 a of the lock holder 23 or being transmitted to the motor shaft 15.

  (3) By extending the tip of the protrusion 52 below the upper surface 23 a of the lock holder 23, it is possible to prevent the hydraulic oil that has flowed down from the protrusion 52 from splashing on the upper surface 23 a of the lock holder 23. .

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
The transmission ratio variable device of this embodiment is different from the transmission ratio variable device of the first embodiment only in the hydraulic oil inflow prevention structure. For this reason, about the same structure, the description is abbreviate | omitted as attaching | subjecting the same code | symbol as the said 1st Embodiment.

  As shown in FIG. 4, the transmission ratio variable device of the present embodiment includes a storage member 62 that stores the lubricant X. The torque limit ring 27 is configured to be immersed in the lubricant X stored in the storage member 62.

  More specifically, in the present embodiment, an annular storage groove 65 is formed on the lower surface 63b of the lock holder 63, and the cylindrical member 62a of the storage member 62 formed in a bottomed cylindrical shape has a storage groove. It is coaxially fixed to the motor shaft 15 in the state of being disposed at 65. As a result, the lubricant X is filled in the fixing portion 49 between the motor shaft 15 and the lock holder 23, and substantially the entire torque limit ring 27 disposed in the fixing portion 49 is immersed in the lubricant X. It has become.

  As described above, according to the present embodiment, even when the hydraulic oil leaked from the hydraulic valve device 4 flows into the fixed portion 49, the lubricant X is not washed away by the hydraulic oil. Thereby, generation | occurrence | production of poor lubrication can be prevented and a relative rotational torque can be maintained stably.

In addition, you may change each said embodiment as follows.
In the first embodiment, the outer diameter R of the hydraulic oil inflow prevention member 50 is larger than the outer diameter r1 of the lock holder 23. However, the present invention is not limited thereto, and as shown in FIG. 5, the outer diameter R of the hydraulic oil inflow prevention member 70 may be at least larger than the outer diameter r2 of the torque limit ring 27. In this case, a recess 74 corresponding to the outer diameter R of the hydraulic oil inflow prevention member 70 may be formed on the upper surface 73a of the lock holder 73 along the periphery thereof. Thereby, it is possible to prevent the hydraulic oil that has flowed down from the hydraulic oil inflow prevention member 70 from flowing into the fixing portion 49 through the upper surface 73a of the lock holder 73.

  -In the said 1st Embodiment, the protrusion 52 formed in cyclic | annular form (cylindrical shape) is protrudingly provided in the periphery of the hydraulic oil inflow prevention member 50 toward the axial direction lower side along the periphery. It was. However, the present invention is not limited to this, and such a sneaking suppression means may be any configuration that can guide the hydraulic oil to flow downward. For example, a plurality of protrusions 81 may be provided as in the hydraulic oil inflow prevention member 80 shown in FIG. In this case, an annular guide wall 82 is provided on the periphery of the upper surface 80a of the hydraulic oil inflow prevention member 80, or the position corresponding to each projection 81 is cut out, or the upper surface 80a and the peripheral surface correspond to each projection 81. It is preferable to provide guiding means for guiding the hydraulic oil on the upper surface 80a to each projection 81, such as by forming a guiding groove 83 to be formed. Thereby, wraparound of hydraulic oil can be suppressed more effectively.

  In the first embodiment, the hydraulic oil inflow prevention member 50 is formed in a substantially disk shape, but the fixing portion 49 between the motor shaft 15 provided with the torque limit ring 27 and the lock holder 23. The shape is not limited to this as long as it can prevent the hydraulic oil from flowing into the tube, and can be formed into a bowl shape or an umbrella shape.

  In the first embodiment, the hydraulic oil inflow prevention member 50 is provided on the motor shaft 15 between the hydraulic valve device 4 and the lock holder 23. However, the present invention is not limited to this, and the configuration may be such that it is provided on the input shaft (middle shaft 12) instead of the motor shaft (motor shaft 15) as long as it is between the hydraulic valve device 4 and the lock holder 23.

  In the second embodiment, the entire torque limit ring 27 is immersed in the lubricant X. However, if a good lubrication state can be maintained by using a capillary phenomenon or the like, The structure which immerses a part of torque limit ring 27 may be sufficient.

The schematic block diagram of the steering gear box in which the transmission ratio variable apparatus was integrated. The schematic block diagram of a locking device. Sectional drawing which shows roughly the hydraulic oil inflow prevention structure of 1st Embodiment. Sectional drawing which shows the hydraulic oil inflow prevention structure of 2nd Embodiment schematically. Sectional drawing which shows schematically the hydraulic oil inflow prevention structure of another example. The perspective view of the hydraulic oil inflow prevention member of another example. Sectional drawing which shows schematically the fixing structure of a motor shaft and a lock holder. The perspective view of a torque limit ring.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Transmission ratio variable device, 4 ... Hydraulic valve device, 9 ... Pinion shaft, 12 ... Middle shaft, 13 ... Motor, 14 ... Wave gear device, 15 ... Motor shaft, 22 ... Lock device, 23, 63, 73 ... Lock Holder, 23a, 73a ... Upper surface, 24 ... Lock arm, 27 ... Torque limit ring, 34 ... Steering shaft, 50, 70, 80 ... Hydraulic oil inflow prevention member, 50a ... Upper surface, 50b ... Lower surface, 52 ... Projection, 62 DESCRIPTION OF SYMBOLS ... Storage member, 74 ... Recessed part, 81 ... Protrusion, 82 ... Guide wall, 83 ... Guide groove, X ... Lubricant, R, r1, r2 ... Outer diameter.

Claims (8)

A differential mechanism that adds rotation based on motor drive to rotation of the input shaft based on steering operation and transmits it to the output shaft, and a lock that restricts rotation of the motor shaft by restraining a lock holder provided on the motor shaft The motor shaft is disposed coaxially with the input shaft, and the relative rotation between the motor shaft and the lock holder is restricted and allowed between the motor shaft and the lock holder based on a frictional resistance. A torque limit ring is interposed, and the input shaft is a transmission ratio variable device connected to a steering shaft via a hydraulic valve device,
A hydraulic oil inflow prevention member having a larger diameter than the torque limit ring is provided on the motor shaft or the input shaft between the hydraulic valve device and the lock holder;
A transmission ratio variable device characterized by the above. The transmission ratio variable device according to claim 1,
The hydraulic oil inflow prevention member is formed to have a larger diameter than the lock holder;
A transmission ratio variable device characterized by the above. The transmission ratio variable device according to claim 1,
The transmission ratio variable device, wherein a concave portion corresponding to the outer diameter of the hydraulic oil inflow prevention member is formed on an upper surface periphery of the lock holder. In the transmission ratio variable device according to any one of claims 1 to 3,
The transmission ratio variable device according to claim 1, wherein the hydraulic oil inflow prevention member includes a sneak suppression means for suppressing sneaking of the hydraulic oil to the lower surface of the hydraulic oil inflow prevention member. The transmission ratio variable device according to claim 4,
The transmission ratio variable device, wherein the wraparound suppression means is a protrusion that is provided at a peripheral edge of the hydraulic oil inflow prevention member and protrudes downward in the axial direction. The transmission ratio variable device according to claim 5,
The protrusion is extended below the upper surface of the lock holder;
A transmission ratio variable device characterized by the above. In the transmission ratio variable device according to claim 5 or 6,
The hydraulic oil inflow prevention member includes guidance means for guiding the hydraulic oil to the protrusion;
A transmission ratio variable device characterized by the above. A differential mechanism that adds rotation based on motor drive to rotation of the input shaft based on the steering operation and transmits it to the output shaft, and a lock that restricts rotation of the motor shaft by restraining a lock holder provided on the motor shaft The motor shaft is disposed coaxially with the input shaft, and the relative rotation between the motor shaft and the lock holder is restricted and allowed between the motor shaft and the lock holder based on a frictional resistance. A torque limit ring is interposed, and the input shaft is a transmission ratio variable device connected to a steering shaft via a hydraulic valve device,
A transmission ratio variable device characterized in that a storage member for storing a lubricant is provided, and the torque limit ring is immersed in the stored lubricant.

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