JP2015009632A - Wheel steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel steering device including a feed screw mechanism that converts a rotational motion of a hollow cylindrical element to a linear motion of a rod and slidably contacting the rod with the hollow cylindrical element by a sliding portion having a sufficient strength against an external force acting in a vertical direction.SOLUTION: A wheel steering device for allowing a rod 12 to make a linear motion in an axial direction by rotation of a hollow cylindrical element 18 around an axis of the rod 12 is provided. The rod 12 slidably contacts a guide surface 18a of the hollow cylindrical element 18 via a C-shaped slide bush 121, rotation of the slide bush 121 around the axis of the rod 12 is restricted by a rotation prevention protrusion 121b, and a C-shaped cut-off portion 121a stops at a position at which the slide bush 121 rotates around the axis of the rod 12 by a predetermined angle with respect to a vertical direction of a vehicle including the wheel steering device.

Description

  The present invention relates to a vehicle wheel steering apparatus.

The technique of four-wheel steering that steers the rear wheels of a four-wheel vehicle whose front wheels are steered according to the driver's steering operation is a widely known technique as described in Patent Document 1, for example.
A rear wheel steering device (wheel steering device) described in Patent Document 1 is configured to steer a rear wheel with a variable total length of a tie rod, and a shaft portion is used to rotate a motor with a ball screw (feed screw mechanism). The total length of the tie rod is changed by converting it into a linear motion of the (rod).

Japanese Patent No. 4942739

The tie rod described in Patent Document 1 is configured such that a linearly moving shaft portion slides on the casing. In such a tie rod, the linear movement of the shaft portion can be smoothed by providing a slide bush (sliding member) on the sliding portion of the shaft portion.
However, since an external force acting in the vertical direction is periodically input to the shaft portion from the rear wheel that vibrates in the vertical direction when the vehicle travels, if the shaft portion is provided with a slide bush, the slide bush is Strength against external force acting in the direction is required.

  For example, in the case of a configuration in which an annular slide bush is fitted in a shaft portion having a circular cross-sectional shape, the annular slide bush has a uniform strength in the circumferential direction, so that it can sufficiently withstand external forces acting in the vertical direction. be able to. However, since a structure for preventing the slide bush from falling off the shaft portion is required, the structure of the shaft portion is complicated.

  Further, if a C-shaped slide bush having a predetermined width and a circumferentially open cutting portion is formed in a part of the annular outer periphery and is discontinuous in the circumferential direction, for example, the operator can cut The C-shaped slide bush can be elastically deformed so as to open the portion and can be fitted into the shaft portion. In this case, if the groove portion into which the slide bush is fitted is recessed in the shaft portion, the slide bush will not fall out, so that a drop-off preventing structure is not required and a shaft portion having a simple structure can be obtained. However, since such a C-shaped slide bush has a fragile cut portion, wear and breakage may occur when an external force is input to the cut portion.

  Therefore, the present invention has a feed screw mechanism that converts the rotational motion of the hollow cylindrical body into the linear motion of the rod, and the rod and the hollow cylindrical body are separated by a sliding portion having sufficient strength against external force acting in the vertical direction. It is an object to provide a wheel steering device that is in sliding contact.

  In order to solve the above problems, the present invention is configured such that an inner tooth formed on an inner peripheral surface of a hollow cylindrical body and an outer tooth formed on an outer peripheral surface of a rod inserted through the hollow cylindrical body are screwed together. A rotary screw output from a motor is provided with a feed screw mechanism that rotates the hollow cylindrical body around the axis of the rod to linearly move the rod in the axial direction, and rotatably supports a wheel serving as a running wheel of the vehicle. A wheel steering device for steering the wheel by rotating a knuckle around a predetermined turning axis with the rod that moves linearly. The rod is slidably contacted with the inner peripheral surface of the hollow cylindrical body via a sliding member that is mounted in a groove portion that is recessed about the axis on the outer peripheral surface, and the sliding member is annular Engagement formed in a C shape having a cut portion opened in the circumferential direction with a predetermined width, and having a protrusion protruding toward the groove, and the protrusion is formed in the groove Engaging with a portion restricts the rotation of the sliding member that rotates about the axis of the rod, and the cutting portion rotates by a predetermined angle around the axis of the rod with respect to the vertical direction of the vehicle. It is characterized by stopping at the position.

  According to the present invention, the inner peripheral surface of the hollow cylindrical body constituting the feed screw mechanism for linearly moving the rod can be brought into sliding contact with the rod via the sliding member. As a result, the rod can be supported on the hollow cylindrical body with a sufficient supporting force. Moreover, since the sliding member is C-shaped, it is easy to be attached to the rod, and it is not necessary to prevent the complicated structure from coming off. And since the C-shaped cutting part stops at a position rotated by a predetermined angle around the axis of the rod with respect to the vertical direction of the vehicle, the cutting part of the external force acting in the vertical direction of the vehicle The component which acts can be made small. Therefore, since the force acting on the cutting portion that is more fragile than other portions is reduced, the sliding member can have sufficient strength against the external force acting in the vertical direction.

  In the present invention, the axial direction of the rod is the vehicle width direction of the vehicle, the predetermined angle is 90 degrees, and the cutting portion stops at a position facing the front or the rear of the vehicle. It is characterized by being.

  According to the present invention, when the axial direction of the rod is the vehicle width direction of the vehicle, the cutting portion is directed to the front or rear of the vehicle (position rotated 90 degrees with respect to the vertical direction). By stopping the sliding member, the force acting on the cutting portion can be reduced most by the external force acting in the vertical direction. Therefore, it can be set as the sliding member which has sufficient intensity | strength with respect to the external force which acts on an up-down direction.

  Further, the present invention is characterized in that the projecting portion protrudes toward the side wall portion of the groove portion, and the engaging portion is formed on the side wall portion.

  According to the present invention, the protrusion formed on the sliding member is engaged with the engaging portion formed on the side wall portion of the groove portion, and the rotation of the sliding member is restricted.

  The sliding member of the present invention has a two-layer structure in which the C-shaped inner peripheral side is formed of a metal part, and a resin part is formed on the outer peripheral side of the metal part.

According to this invention, it can be set as the sliding member which formed the C-shaped inner peripheral side with the metal part. Since the metal portion has elasticity, the sliding member can be elastically deformed so that the cutting portion opens, and can be a sliding member that can be easily attached to the rod. Moreover, since the sliding member has the resin portion formed on the outer peripheral side of the metal portion, the sliding performance with respect to the hollow cylindrical body is improved.
If the resin part is not formed on the sliding member, the metal part comes into sliding contact with the hollow cylinder, but the hollow cylinder is often made of metal (such as an aluminum alloy) in order to ensure strength. Metals are in sliding contact with each other. And at least one of a sliding member or a hollow cylindrical body may be worn out violently. Since the sliding member of the present invention has a resin portion formed on the outer peripheral side, sliding contact between metals can be avoided, and wear can be suppressed thereby improving sliding performance.

  In the present invention, the wheel includes a front wheel disposed in front of the vehicle and a rear wheel disposed in the rear of the vehicle, and a wheel steering device is capable of rotating the rear wheel. The knuckle that is supported by the wheel is rotated by the rod to steer the rear wheel.

  According to the present invention, it is possible to provide a vehicle steering apparatus capable of steering the rear wheels of a vehicle (four-wheel vehicle) having front wheels and rear wheels.

  According to the present invention, the rod and the hollow cylinder are slid by the sliding portion having a sufficient strength against the external force acting in the vertical direction, which has a feed screw mechanism that converts the rotational movement of the hollow cylinder into the linear movement of the rod. A wheel steering device in contact can be provided.

It is a figure which shows the rear suspension periphery of the vehicle incorporating the wheel steering device which concerns on this embodiment. It is a longitudinal section of the wheel steering device concerning this embodiment. (A) is a perspective sectional view showing the structure of the sliding surface formed on the guide surface and the rod formed on the inner peripheral surface of the hollow cylindrical body, and (b) is the enlarged diameter portion and the expanded diameter portion of the sliding portion. It is a perspective view which shows the slide bush wrapped around. It is a figure which shows typically the external force input into a slide bush, (a) is a figure which shows the state which the cutting part faced the upper direction of the vehicle, (b) is only (theta) degree with respect to the upper part of a vehicle. It is a figure which shows the state which exists in the rotated position. It is a figure which shows the two-layer structure of a slide bush.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
FIG. 1 is a view showing a periphery of a rear suspension of a vehicle in which a wheel steering device according to this embodiment is incorporated.
As shown in FIG. 1, a rear suspension 2 provided in a vehicle (four-wheel steering vehicle) 1 of the present embodiment is, for example, a double wishbone type, and rotates a wheel (rear wheel 3) serving as a traveling wheel of the vehicle 1. The knuckle 4 is supported freely, the upper arm 5 and the lower arm 6 are connected to the vehicle body so that the knuckle 4 can be moved up and down, and the wheel alignment such as the toe angle and camber angle of the rear wheel 3 can be controlled (adjusted / changed). And a damper 8 for buffering the vertical movement of the rear wheel 3. The wheel steering device 7 has one end serving as a base end connected to a vehicle body (not shown) via a rubber bush joint 9 and one end serving as a tip connected to the rear part (or rear lower part) of the knuckle 4 via a rubber bush joint 10. It is connected to.

  Furthermore, the knuckle 4 of the present embodiment is connected to the lower arm 6 via the steered shaft 3a, and is configured to be rotatable around the steered shaft 3a with respect to the lower arm 6. And the knuckle 4 is comprised so that the rear-wheel 3 may steer, turning centering on the steering shaft 3a.

FIG. 2 is a longitudinal sectional view of the wheel steering apparatus according to the present embodiment.
As shown in FIG. 2, the wheel steering device 7 includes a housing 11 integrally provided with a rubber bush joint 9 connected to a vehicle body (not shown) and a rubber bush connected to the knuckle 4 (see FIG. 1). And a rod 12 provided integrally with the joint 10. The rubber bush joint 10 is formed at the end of the rod 12 in the longitudinal direction. The rod 12 includes the rubber bush joint 10 (tip) and the rubber bush joint 9 (base end) at both ends of the wheel steering device 7 in the longitudinal direction of the rod 12. It is equipped to become. Further, the rod 12 is provided so as to be capable of being accommodated by being displaced in the longitudinal direction with respect to the housing 11, and when the rod 12 is displaced in the direction of entering the housing 11, the wheel steering device 7 contracts. On the other hand, when the rod 12 is displaced in the direction of exiting the housing 11, the wheel steering device 7 extends.

When the wheel steering device 7 is extended, the rear part (or rear lower part) of the knuckle 4 shown in FIG. 1 is pushed outward in the vehicle width direction so that the knuckle 4 rotates about the turning shaft 3a. The angle changes in the toe-in direction (changes in the direction in which the camber angle decreases). When the wheel steering device 7 is contracted, the rear part (or rear lower part) of the knuckle 4 is pulled inward in the vehicle width direction so that the knuckle 4 rotates about the turning shaft 3a, and the toe angle of the rear wheel 3 becomes the toe-out direction. (Changes in the direction in which the camber angle increases).
Thus, the wheel steering device 7 of the present embodiment is configured such that the rod 12 that moves linearly rotates the knuckle 4 around the steered shaft 3 a to steer the rear wheel 3.

For example, the wheel steering device 7 may be controlled by a control device (not shown). In this case, when the turning angle of a front wheel (steered wheel) (not shown) is small, the wheel steering device 7 may be controlled so that the rear wheel 3 shown in FIG. 1 steers in the same direction as the front wheel ( In-phase control). Thereby, for example, a stable lane change (change of the travel lane) of the vehicle 1 traveling on the highway is realized.
Moreover, it is good also as a structure by which the wheel steering device 7 is controlled so that the rear wheel 3 steers in the direction opposite to the front wheel when the turning angle of the front wheel (steered wheel) is large (reverse phase control). As a result, the turning radius of the vehicle 1 is reduced and the turning performance is improved.

  Thus, the vehicle 1 provided with the wheel steering device 7 controlled by the control device (not shown) can improve the running performance. The above-described in-phase control and reverse-phase control are only examples, and the wheel steering device 7 is in a traveling state (high speed traveling, low speed traveling, collision avoidance traveling, etc.) of the vehicle 1 or a traveling road surface state (inclined road, low road). Any configuration may be used as long as it is appropriately controlled according to the μ path and the like.

  The wheel steering device 7 of the present embodiment is configured to extend and contract by a linear motion in the longitudinal direction of the rod 12 to steer the rear wheel 3 (see FIG. 1). Reference) is configured to linearly move in the vehicle width direction. That is, the direction in which the rod 12 moves linearly is the vehicle width direction of the vehicle 1. Therefore, in FIG. 2, the vertical direction is the front-rear direction of the vehicle 1. For example, when the upper side of FIG. 2 is the front side of the vehicle 1, the lower side is the rear side of the vehicle 1.

The housing 11 is provided with a brushed motor 13 as a drive source, a speed reducer 17, and a feed screw mechanism 20. The motor 13 rotates the rotary shaft 14 connected to the speed reducer 17. The reduction gear 17 is composed of a plurality of gears (in the example of FIG. 2, it is composed of two of the first gear 15 and the second gear 16).
The first gear 15 is directly connected to the rotating shaft 14 (for example, formed on the rotating shaft 14) and rotates at the same rotational speed as the rotating shaft 14. The second gear 16 is a gear having a diameter (tooth diameter) larger than that of the first gear 15. In other words, the second gear 16 is the gear having the largest tooth tip diameter among the plurality of gears (the first gear 15 and the second gear 16) constituting the reduction gear 17.

  The second gear 16 meshes with the first gear 15, and itself rotates in accordance with the rotational movement of the first gear 15. Since the second gear 16 has a larger tip circle diameter than the first gear 15, the rotation speed of the second gear 16 is slower than the rotation speed of the first gear 15. Thus, the reduction gear 17 is comprised so that the rotational speed of the motor 13 (rotary shaft 14) may be decelerated with the 1st gear 15 and the 2nd gear 16 which mutually mesh | engage.

  The wheel steering device 7 includes a rotating portion (inner teeth 20a formed on the inner peripheral surface of the hollow cylindrical body 18) and a linear motion portion (external teeth 20b formed on the outer peripheral surface of the rod 12). The feed screw mechanism 20 is provided. The rod 12 is inserted through the hollow cylindrical body 18 in the axial direction. The hollow cylindrical body 18 is attached to the housing 11 via a bearing member 11 a such as a rolling bearing and is configured to be rotatable around the axis of the rod 12. The hollow cylindrical body 18 is configured to be rotatable integrally with the second gear 16 of the speed reducer 17. Therefore, the rotational motion of the motor 13 (rotating shaft 14) is transmitted to the hollow cylindrical body 18 with the rotational speed reduced by the speed reducer 17. That is, the hollow cylindrical body 18 rotates around the axis of the rod 12 by the rotational power output from the motor 13. In the present embodiment, the axial direction of the rod 12 is the vehicle width direction of the vehicle 1 (see FIG. 1).

Further, the external teeth 20b of the rod 12 inserted through the hollow cylindrical body 18 and the internal teeth 20a of the hollow cylindrical body 18 are configured to be screwed together.
Since the rod 12 on which the external teeth 20b are formed is restricted from rotating about the axis, when the hollow cylindrical body 18 rotates, the external teeth 20b that mesh with the internal teeth 20a are sent in the axial direction of the rod 12, and the rod 12 Move linearly in the axial direction. Thus, the rotational movement of the hollow cylindrical body 18 is converted into the linear movement of the rod 12 by the feed screw mechanism 20. And the rod 12 is displaced with respect to the housing 11 by this linear motion, and expands and contracts the wheel steering device 7.

  As shown in FIG. 2, the housing 11 includes a boot 11 b that covers the rod 12 and the hollow cylindrical body 18 from the outside and expands and contracts according to the displacement of the rod 12. By providing such a boot 11b, foreign matter such as dust is prevented from adhering to the hollow cylindrical body 18 and the like, and the smooth linear motion (displacement) of the rod 12 is maintained.

  As described above, the feed screw mechanism 20 is configured such that the external teeth 20b formed on the rod 12 are screwed with the internal teeth 20a of the hollow cylindrical body 18, and the rod 12 is displaced by the rotation of the hollow cylindrical body 18. The However, in a configuration in which the rod 12 is supported by the hollow cylindrical body 18 only by screwing the inner teeth 20a and the outer teeth 20b, sufficient support force cannot be obtained. For example, when an external force input from the rear wheel 3 (see FIG. 1) to the rod 12 via the rubber bush joint 10 generates a moment about the internal teeth 20a of the hollow cylindrical body 18 on the rod 12, the rod 12 Inclined with respect to the hollow cylindrical body 18, the smooth linear movement (displacement) of the rod 12 is hindered.

Therefore, the sliding portion 12 a is formed at the end of the rod 12, and the sliding portion 12 a is in sliding contact with the guide surface 18 a formed on the inner peripheral surface of the hollow cylindrical body 18.
The guide surface 18a is formed as a part of the inner peripheral surface of the hollow cylindrical body 18, and is formed so that the sliding portion 12a of the rod 12 is in sliding contact with the guide surface 18a. With such a configuration, a moment is generated in the rod 12 around the inner teeth 20a of the hollow cylindrical body 18 by an external force input to the rod 12 from the rear wheel 3 (see FIG. 1) via the rubber bush joint 10. Even so, the rotation of the sliding portion 12a is restricted by the contact between the sliding portion 12a and the guide surface 18a, and the inclination of the rod 12 is suppressed.

3A is a perspective cross-sectional view showing the structure of the sliding portion formed on the guide surface and the rod formed on the hollow cylindrical body, and FIG. 3B is the enlarged diameter portion and the enlarged diameter portion of the sliding portion. It is a perspective view which shows the slide bush mounted.
As shown in FIG. 3A, the sliding portion 12 a includes an enlarged diameter portion 120 in which an end portion of the rod 12 (an end portion on the opposite side of the rubber bush joint 10) is expanded, and an outer periphery of the expanded diameter portion 120. And a sliding member (sliding bush 121) that is mounted on. The sliding portion 12 a is configured such that the slide bush 121 mounted around the enlarged diameter portion 120 is in sliding contact with the guide surface 18 a of the hollow cylindrical body 18.

As shown in FIG. 3 (b), the enlarged diameter portion 120 has a cylindrical shape centered on the axis of the rod 12, and on the outer periphery of the enlarged diameter portion 120, side wall portions 120b stand up at both ends of the groove bottom portion 120a. The groove is recessed. The slide bush 121 has an annular shape that is mounted around the groove bottom portion 120a of the enlarged diameter portion 120 and fits into the groove portion.
Since the enlarged diameter portion 120 is formed by expanding the diameter of the rod 12, the groove portions (groove bottom portion 120 a and side wall portion 120 b) provided in the outer periphery of the enlarged diameter portion 120 are provided in the outer peripheral surface of the rod 12. It will be. Therefore, the slide bush 121 mounted around the outer periphery of the enlarged diameter portion 120 is mounted around the groove portion recessed in the outer peripheral surface of the rod 12.

The enlarged diameter portion 120 is formed to adjust the dimensional difference between the outer diameter of the rod 12 and the inner diameter of the guide surface 18a, and the dimensional difference between the outer diameter of the rod 12 and the inner diameter of the guide surface 18a is small. In this case, the sliding part 12a in which the enlarged diameter part 120 is not formed may be used.
In this case as well, a groove portion (groove bottom portion 120a, side wall portion 120b) may be provided in the outer peripheral surface of the rod 12, and the slide bush 121 may be mounted around the groove portion.

  In addition, the slide bush 121 of the present embodiment is formed with a cutting portion 121a that opens in a ring-shaped circumferential direction with a predetermined width, and the slide bush 121 is C-shaped (discontinuous in the circumferential direction) in a side view. (Annular). In addition, the magnitude | size of the width | variety (width of the circumferential direction) of the cutting part 121a is not limited.

  Further, the slide bush 121 has a claw-like portion (rotation) that prevents rotation (rotation) around the axis of the rod 12 along the groove bottom portion 120a in a state of being mounted on the enlarged diameter portion 120 of the rod 12. A movement preventing projection 121b) is formed. The rotation prevention protrusion 121b is formed as a protrusion protruding from the end of the slide bush 121 mounted around the enlarged diameter portion 120 toward the side wall 120b.

  Further, the enlarged diameter portion 120 of the rod 12 is formed with an engaging portion 120c with which the rotation preventing projection 121b is engaged. The engaging portion 120c is formed by cutting a part of the side wall portion 120b into the shape of the rotation preventing projection 121b, and is rotated when the slide bush 121 is mounted on the groove bottom portion 120a of the enlarged diameter portion 120. The prevention protrusion 121b is configured to fit into the engagement portion 120c. The rotation of the slide bush 121 along the groove bottom 120a (the rotation about the axis of the rod 12) is restricted by the engagement of the rotation prevention protrusion 121b and the engagement portion 120c.

  Further, when the rotation preventing protrusion 121b and the engaging portion 120c are engaged, the cutting portion 121a has a predetermined angle θ degree forward (or “0 <θ”) with respect to the upper side of the vehicle 1 (see FIG. 1). It is preferable that the slide bush 121 is mounted on the enlarged diameter portion 120 so as to face in the direction of rotation by <180>.

  4A and 4B are diagrams schematically showing an external force input to the slide bush. FIG. 4A is a diagram showing a state in which the cutting portion faces upward of the vehicle, and FIG. 4B is a diagram showing the cutting portion with respect to the upper side of the vehicle. It is a figure which shows the state in the position rotated only (theta) degree. FIG. 5 is a view showing a two-layer structure of the slide bush. 4A and 4B are diagrams (schematic diagrams) in which the enlarged diameter portion 120 and the guide surface 18a are viewed from the axial direction of the rod 12. FIG. 4A and 4B show the gap between the slide bush 121 and the guide surface 18a in an exaggerated manner. The actual slide bush 121 has a large gap on the inner peripheral surface of the guide surface 18a. There is no sliding contact.

  When the vehicle 1 (see FIG. 1) travels, the rear wheel 3 (see FIG. 1) vibrates in the vertical direction according to the unevenness of the road surface, and the vibration is applied to the rod 12 via the rubber bush joint 10 (see FIG. 2). Communicated. Therefore, an external force (indicated by “Pv” in FIG. 4) acting in the vertical direction is periodically input to the rod 12 while the vehicle 1 is traveling. The external force Pv input to the rod 12 is transmitted to the enlarged diameter portion 120 and input to the hollow cylindrical body 18 (guide surface 18a) via the slide bush 121. Therefore, as shown in FIG. 4A, the external force Pv acting in the vertical direction is input to the slide bush 121 mounted around the enlarged diameter portion 120.

  As shown in FIG. 4 (a), when the cutting part 121a faces upward of the vehicle 1 (see FIG. 1), an external force Pv acting upward is periodically input to the position of the cutting part 121a. Thus, the cutting part 121a is periodically pressed against the guide surface 18a. When the rod 12 moves linearly while the cutting part 121a is pressed against the hollow cylindrical body 18, the slide bush 121 slides on the guide surface 18a while the part of the cutting part 121a is pressed. A portion (for example, an end portion) of the cutting portion 121a is a portion that is weaker than other portions. When the slide bush 121 slides on the guide surface 18a in a state where this portion is pressed by the external force Pv, the slide bush 121 Wear and breakage of

  However, as shown in FIG. 4B, when the cutting part 121a is in a position rotated by an angle of “θ degrees” with respect to the upper side of the vehicle 1 (see FIG. 1), A cosine component (Pv × Cos θ) of the external force Pv acting upward acts. Therefore, the force acting on the cutting part 121a is reduced, and wear and breakage of the slide bush 121 when the rod 12 moves linearly are suppressed.

  Note that the wear and breakage of the slide bush 121 are most suppressed when the cosine component of the external force Pv acting in the direction of the cutting portion 121a is the smallest, and the angle “θ degree” shown in FIG. Is “90 degrees”. That is, the cutting part 121a is at a position rotated 90 degrees around the axis of the rod 12 with respect to the vertical direction of the vehicle 1 (see FIG. 1) along the groove bottom part 120a (see FIG. 3B). (When the cutting part 121a is at a position rotated 90 degrees around the axis of the rod 12 with respect to the vertical direction of the vehicle 1), the cosine component of the external force Pv acting in the direction of the cutting part 121a is the smallest. And in this state, the abrasion and damage of the cutting part 121a are most suppressed.

  4A and 4B, the external force Pv acting in the upward direction has been described. However, when the cutting portion 121a is disposed in the downward direction, the slide bush 121 is driven by the external force acting in the downward direction. Wear and breakage of

  In the present embodiment, the axial direction of the rod 12 including the enlarged diameter portion 120 around which the slide bush 121 is mounted is the vehicle width direction of the vehicle 1 (see FIG. 1), and the slide bush 121 rotates about the axis of the rod 12. Therefore, when the slide bush 121 rotates 90 degrees from the state in which the cutting part 121 a faces upward of the vehicle 1, the cutting part 121 a faces the front or rear of the vehicle 1. Therefore, when the cutting part 121a is in a position facing the front or the rear of the vehicle 1, the wear and breakage of the slide bush 121 are most suppressed.

  However, as shown in FIG. 3A, the slide bush 121 is configured to be mounted on the groove bottom 120a (see FIG. 3B) of the cylindrical enlarged diameter portion 120, and the groove bottom 120a. The position of the cutting part 121a cannot be stopped by the slide bush 121 that does not have the function of restricting the rotation around the axis of the rod 12 along the axis.

Therefore, the wheel steering device 7 (see FIG. 2) of the present embodiment is provided with the rotation prevention protrusion 121b on the slide bush 121 and on the side wall 120b of the diameter-expanded portion 120 as shown in FIG. The engaging portion 120c is provided, and the rotation preventing projection 121b is engaged with the engaging portion 120c so that the rotation of the slide bush 121 can be restricted.
With this configuration, the cutting part 121a is stopped at a position rotated by a predetermined angle θ degrees (for example, only 90 degrees) around the axis of the rod 12 with respect to the vertical direction of the vehicle 1 (see FIG. 1). The slide bush 121 can be maintained (fixed), and wear and breakage of the slide bush 121 can be suppressed.
For example, when the axial direction of the rod 12 is the vehicle width direction of the vehicle 1, the slide bush 121 is maintained (fixed) in a state where the cutting portion 121 a is stopped at a position rotated forward or backward relative to the upper side of the vehicle 1. ) And wear and breakage of the slide bush 121 are suppressed.

  Note that the angle θ that determines the position of the cutting portion 121a of the slide bush 121 includes, for example, the travel performance required for the vehicle 1 (see FIG. 1), the strength of the slide bush 121, and the engagement portion 120c on the side wall portion 120b. The characteristic value of the vehicle 1 may be appropriately determined in consideration of the workability at the time of processing.

  A configuration in which the rod 12 shown in FIG. 3A linearly moves in the front-rear direction of the vehicle 1 (see FIG. 1) to rotate the knuckle 4 (see FIG. 1) is also conceivable. In this case, the axial direction of the rod 12 is the front-rear direction of the vehicle 1. Therefore, when the slide bush 121 rotates around the axis of the rod 12 from the state in which the cutting portion 121a faces upward, the cutting portion 121a rotates in the vehicle width direction (left or right) of the vehicle 1. To do. Therefore, when the cutting part 121a is stopped at a position rotated leftward or rightward relative to the upper side of the vehicle 1, wear and damage of the slide bush 121 are suppressed.

  In addition, as shown in FIG. 5, the slide bush 121 of the present embodiment has a two-layer structure in which a C-shaped inner peripheral side is formed of a metal part (metal back metal 122a) and an outer peripheral side is formed of a resin part 122b. The structure. The slide bush 121 can be suitably slid with the guide surface 18a (see FIG. 3A) of the hollow cylindrical body 18 by forming the outer peripheral side with the resin portion 122b.

Moreover, since the slide bush 121 is formed of the back metal 122a on the inner peripheral side, the discontinuous annular shape (C-shape) is maintained by the elasticity of the back metal 122a. And when the cut part 121a is formed in the slide bush 121, the slide bush 121 can be elastically deformed so that the cut part 121a can be opened by the elasticity of the back metal 122a. Accordingly, the slide bush 121 is fitted to the enlarged diameter portion 120 (groove portion) by opening the cutting portion 121a so that the groove bottom portion 120a (see FIG. 3B) passes. Further, the slide bush 121 fitted to the groove bottom portion 120a is kept fitted to the enlarged diameter portion 120 when the back metal 122a maintains the C shape.
By adopting such a configuration, a mechanism for preventing the slide bush 121 from being detached becomes unnecessary, and the diameter-enlarged portion 120 (rod 12) having a simple structure can be obtained.

  As described above, in the wheel steering device 7 (see FIG. 1) of the present embodiment, the sliding portion 12a of the rod 12 that linearly moves slides on the guide surface 18a of the hollow cylindrical body 18, as shown in FIG. Configured as follows. Therefore, the inclination of the rod 12 due to the external force input to the rod 12 from the rear wheel 3 (see FIG. 1) via the rubber bush joint 10 is suppressed, and the smooth linear motion of the rod 12 is maintained. Further, as shown in FIGS. 3A and 3B, the sliding portion 12a is configured such that the slide bush 121 is mounted around the groove portion (groove bottom portion 120a, side wall portion 120b) of the enlarged diameter portion 120. .

As shown in FIG. 3B, the slide bush 121 is formed with a cutting portion 121a that opens with a predetermined width in an annular circumferential direction, and has a C-shape in a side view. Also, as shown in FIG. 5, the slide bush 121 has a two-layer structure including a metal part (back metal 122a) on the inner peripheral side and a resin part 122b on the outer peripheral side. Elastic deformation such that 121a is opened is possible.
Therefore, if the groove portion as shown in FIG. 3B is formed on the outer periphery of the enlarged diameter portion 120, the slide bush 121 does not fall off the enlarged diameter portion 120 without falling off due to the elastic force of the back metal 122a. Be dressed. For this reason, it is not necessary to prevent the diameter-expanded portion 120 from having a complicated structure, and the rod 12 having a simple structure can be obtained.

Further, the slide bush 121 according to the present embodiment is formed with a rotation prevention protrusion 121b that restricts the rotation around the axis of the rod 12 along the groove bottom portion 120a of the diameter expansion portion 120. The side wall 120b is formed with an engaging portion 120c with which the rotation preventing projection 121b is engaged. Therefore, the cutting part 121a of the slide bush 121 mounted around the enlarged diameter part 120 can be stopped at a predetermined position. As a result, the cutting portion 121a is stopped at a position where wear or breakage of the slide bush 121 is suppressed (for example, a position rotated by a predetermined angle θ degrees around the axis of the rod 12 with respect to the vertical direction of the vehicle 1). It is possible to make the sliding part 12a resistant to wear and breakage.
For example, when the axial direction of the rod 12 is the vehicle width direction of the vehicle 1, the cutting part 121 a can be stopped at a position facing the front or the rear of the vehicle 1.

The present invention is not limited to the above-described embodiment, and can be appropriately changed in design without departing from the spirit of the invention.
For example, a configuration in which two or more rotation preventing protrusions 121b of the slide bush 121 and two engaging portions 120c of the enlarged diameter portion 120 are formed as shown in FIG.
Moreover, the structure which the engaging part 120c is formed in both the side wall parts 120b formed in the both sides of the groove bottom part 120a, and the rotation prevention protrusion 121b may be formed corresponding to the engaging part 120c may be sufficient. .

Further, as shown in FIG. 3B, the rotation preventing projection 121b of the present embodiment protrudes toward the side wall portion 120b of the enlarged diameter portion 120, and an engaging portion 120c is formed on the side wall portion 120b. The configuration. However, for example, the rotation preventing projection 121b is projected toward the groove bottom 120a of the enlarged diameter portion 120, and an engaging portion (not shown) with which the rotation preventing projection 121b engages is formed on the groove bottom 120a. It may be a configuration.
Further, although not shown in the drawing, a rotation preventing projection consisting of a projection protruding from the groove bottom 120 a of the enlarged diameter portion 120 toward the slide bush 121 is formed on an engagement portion (concave) formed on the slide bush 121. The structure which engages may be sufficient.

  Further, the configuration of the slide bush 121 is not limited to the two-layer structure shown in FIG. For example, the slide bush 121 may be configured by a resin core 122b covering a metal core (not shown).

  Moreover, when the removal from the enlarged diameter part 120 of the slide bush 121 is unnecessary, the structure by which the slide bush 121 is stuck on the groove bottom part 120a of the enlarged diameter part 120 may be sufficient. With this configuration, the rotation prevention protrusion 121b of the slide bush 121 and the side wall 120b of the enlarged diameter portion 120 are not necessary, and the sliding portion 12a (rod 12) having a simpler shape can be obtained.

1 vehicle 3 rear wheel (wheel)
3a Steering shaft 4 Knuckle 7 Wheel steering device 12 Rod 12a Sliding part 13 Motor 18 Hollow cylindrical body 18a Guide surface (inner peripheral surface on which the sliding part slides)
20 Feed screw mechanism 20a Internal teeth 20b External teeth 120a Groove bottom (groove)
120b Side wall (groove)
120c engagement part 121 slide bush (sliding member)
121a Cutting part 121b Anti-rotation protrusion (protrusion part)
122a Back metal (metal part)
122b Resin part

Claims (5)

The internal teeth formed on the inner peripheral surface of the hollow cylindrical body and the external teeth formed on the outer peripheral surface of the rod inserted through the hollow cylindrical body are screwed together to rotate the hollow A cylindrical body rotates around the axis of the rod and includes a feed screw mechanism that linearly moves the rod in the axial direction.
A wheel steering device that steers the wheel by rotating a knuckle that rotatably supports a wheel serving as a traveling wheel of the vehicle around a predetermined turning shaft with the rod that linearly moves,
The rod slidably contacts the inner peripheral surface of the hollow cylindrical body through a sliding member that is mounted in a groove portion that is recessed around the axis on the outer peripheral surface;
The sliding member is formed in a C shape having a cut portion opened with a predetermined width in the annular circumferential direction, and has a protruding portion protruding toward the groove portion,
The protrusion is engaged with an engaging portion formed in the groove portion to restrict the rotation of the sliding member that rotates around the axis of the rod,
The wheel steering device according to claim 1, wherein the cutting portion is stopped at a position rotated by a predetermined angle around an axis of the rod with respect to a vertical direction of the vehicle. The axial direction of the rod is the vehicle width direction of the vehicle, and the predetermined angle is 90 degrees,
The wheel steering device according to claim 1, wherein the cutting portion is stopped at a position facing the front or the rear of the vehicle. The protrusion is provided to protrude toward the side wall of the groove;
The wheel steering apparatus according to claim 1, wherein the engagement portion is formed on the side wall portion.   The sliding member has a two-layer structure in which an inner peripheral side of the C-shape is formed of a metal part and a resin part is formed on the outer peripheral side of the metal part. The wheel steering device according to any one of the above. The wheels include a front wheel disposed in front of the vehicle and a rear wheel disposed in the rear of the vehicle.
The wheel steering apparatus according to any one of claims 1 to 4, wherein the knuckle that rotatably supports the rear wheel is rotated by the rod to steer the rear wheel.

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