JP2013226870A - Steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steering device capable of improving design flexibility avoiding interference with an engine and a transmission as much as possible.SOLUTION: A steering device 20, which is of a rack and pinion type, includes: a pinion shaft 25 coupled with a steering wheel 8: and a rack shaft 26, which has rack teeth 28 that mesh with a pinion 24 of the pinion shaft 25. The rack shaft 26 is accommodated inside a cylindrical reinforcement 11, which is a part of a vehicle body 1 and supported movably in an axial direction X by the reinforcement 11. The steering device 20 includes: tie rods 36 coupled with turning wheels 22; and link arms 35 which are coupled with the axial ends (joint members 30) of the rack shaft 26 and the tie rods 36 to steer the turning wheels 22 with the movement of the rack shaft 26.

Description

  The present invention relates to a steering device.

  With respect to the steering device, Patent Literature 1 below discloses a steering column. The steering column is attached to a deck cloth provided in the vehicle interior of the vehicle body via a support bracket. In the steering column, a steering wheel is attached to the base end portion via a steering shaft, while the tip end portion extends into the engine compartment through a dash panel that partitions the vehicle compartment and the engine compartment in the vehicle body. The front wheel steering mechanism is connected.

Japanese Patent Laid-Open No. 10-264830

In Patent Document 1, since the front wheel steering mechanism is disposed on the engine room side, it is necessary to consider interference between the front wheel steering mechanism and the engine and transmission in the engine room. In order to avoid this interference, the front wheel steering mechanism is often subject to structural limitations, and in this case, the degree of freedom in designing the front wheel steering mechanism is reduced.
The present invention has been made under such a background, and an object of the present invention is to provide a steering apparatus capable of avoiding interference with an engine and a transmission as much as possible and improving design freedom.

  The invention according to claim 1 is a rack including a pinion shaft (25) connected to the steering member (8) and a rack shaft (26) having rack teeth (28) meshing with the pinion (24) of the pinion shaft. An and pinion type steering device (20), wherein the rack shaft is accommodated in a tubular lean hose (11) which is a part of the vehicle body (1), and is axially (X) driven by the lean hose. The tie rod (36) connected to the steered wheel (22) and the axial end of the rack shaft and the tie rod are connected to the steered wheel (22), and the steered wheel is rotated as the rack shaft moves. A steering device including a link arm (35) for steering.

  The invention according to claim 2 is characterized in that the link arm includes one end (35A) connected to the axial end of the rack shaft, the other end (35B) connected to the tie rod, the one end and The fulcrum (39) located between the other end portions and coupled to the vehicle body, and swingable about the fulcrum as the rack shaft moves. This is a steering device.

The invention according to claim 3 is the steering apparatus according to claim 2, wherein one end of the link arm and the axial end of the rack shaft are connected with play.
The invention according to claim 4 further includes: a motor (51) that generates a driving force for steering the steering member; and a speed reducer (52) that decelerates the driving force generated by the motor and transmits the driving force to the steering member. The steering device according to any one of claims 1 to 3, wherein the steering device is included.

  According to a fifth aspect of the present invention, there is provided a screw shaft portion (61) provided on the rack shaft, and a ball externally fitted to the screw shaft portion and screw-coupled to the screw shaft portion via a ball (64). The rack shaft includes a nut (62) and a motor (65) for rotating the ball nut, and the rack shaft is moved in the axial direction by changing a relative coupling position between the ball nut and the screw shaft portion. The steering device according to any one of claims 1 to 3, further comprising a ball nut mechanism (60) for assisting.

  In addition, in the above, the numbers in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

  According to the first aspect of the present invention, in the steering device, when the pinion shaft rotates in accordance with the steering of the steering member, the rack shaft moves in the axial direction, and the link arm moves the tie rod in conjunction with the movement of the rack shaft. Since it moves, turning of the steered wheels can be realized. Here, since the rack shaft that is relatively bulky in the steering device is housed in a lean hose that is a part of the vehicle body, interference between the engine or transmission and the steering device (particularly the rack shaft) is avoided. . Therefore, the steering device can be designed without considering interference with the engine and the transmission. That is, it is possible to provide a steering device that can avoid the interference with the engine and the transmission as much as possible and can improve the degree of freedom in design.

According to the second aspect of the present invention, the steered wheels can be steered by moving the tie rod by swinging the link arm around the fulcrum connected to the vehicle body as the rack shaft moves.
According to the invention of claim 3, when the link arm swings, a force in a direction different from the axial direction (for example, a direction orthogonal to the axial direction) acts on the rack shaft from the link arm. It is possible to prevent the smooth axial movement of the rack shaft from being hindered.

According to the fourth aspect of the invention, steering of the steering member can be assisted by transmitting the driving force generated by the motor to the steering member after being decelerated by the reduction gear.
According to the fifth aspect of the present invention, the steering of the steering member can be assisted by assisting the movement of the rack shaft in the axial direction by the ball nut mechanism.

FIG. 1 is a schematic diagram for explaining a main part of the vehicle body 1. FIG. 2 is a schematic diagram showing a schematic configuration of the steering device 20 according to the embodiment of the present invention. FIG. 3 is a view for explaining a procedure for attaching the link arm 35 to the end of the rack shaft 26. FIG. 4 is a diagram showing in detail the main part of FIG. FIG. 5 is a schematic cross-sectional view of a ball nut mechanism 60 applied to the steering device 20 as a modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram for explaining a main part of the vehicle body 1.
Referring to FIG. 1, a general passenger car body (body frame) 1 has a dash panel 2 (a part of the vehicle body 1) extending vertically in front of the dash panel 2 (left side in FIG. 1). The engine room 3 and a vehicle compartment 4 on the rear side (right side in FIG. 1) of the dash panel 2 are partitioned.

In the engine room 3, an engine 5, a transmission 6, and the like are arranged.
In the passenger compartment 4, a seat 7, a steering wheel 8 as a steering member, a steering column 9, and the like are arranged.
Here, the dash panel 2 is provided with a stay 10 extending rearward (seat 7 side) toward the inside of the passenger compartment 4. For example, the side cross section of the rear end portion of the stay 10 has a U-shape inclined rearward. A lean hose 11 is attached to the rear end portion of the stay 10. The lean hose 11 has a tubular shape (circular tubular shape in this case) that is long in the vehicle width direction of the vehicle body 1 (the direction perpendicular to the paper surface in FIG. 1). For convenience of explanation, only the side cross-sectional portion of the lean hose 11 is hatched in FIG. Regarding the attachment of the lean hose 11, the vehicle body 1 has a bracket 12 having a U-shaped side section inclined to the front side. A lean hose 11 is disposed behind the rear end of the stay 10, a bracket 12 is disposed behind the lean hose 11, and the lean hose 11 is sandwiched from the front and rear by the rear end of the stay 10 and the bracket 12. The rear end and the bracket 12 are combined with a bolt 13. Accordingly, the lean hose 11 is fixed to the stay 10 (dash panel 2) and is a part of the vehicle body 1.

The steering column 9 (including the steering wheel 8 supported by the steering column 9) is fixed to the lean hose 11.
The vehicle body 1 is provided with a steering device 20.
FIG. 2 is a schematic diagram showing a schematic configuration of the steering device 20 according to the embodiment of the present invention. In FIG. 2, the steering device 20 and its surrounding parts are viewed from the front of the vehicle body 1.

Referring to FIG. 2, the steering device 20 rotates in conjunction with the steering column 9 (not shown in FIG. 2 and later), the steering shaft 21 to which the steering wheel 8 is connected, and the rotation of the steering wheel 8. And a steering mechanism 23 that steers the steered wheels 22.
The steering shaft 21 extends in the up-down direction while being tilted back and forth. The steering shaft 21 is accommodated in the steering column 9 with its upper end protruding, and is rotatably supported by the steering column 9 (see FIG. 1). A steering wheel 8 is connected to the upper end portion of the steering shaft 21.

  A pinion 24 is provided midway in the length direction of the steering shaft 21. Hereinafter, the portion where the pinion 24 is provided in the steering shaft 21 is referred to as a pinion shaft 25. In the steering shaft 21, the pinion shaft 25 and other portions may be integrated as shown in FIG. 2, or may be connected in a separable manner. However, in the steering shaft 21, if the pinion shaft 25 and the other portion are integrated, the rotation of the steering wheel 8 can be transmitted to the steering mechanism 23 evenly.

  The steering mechanism 23 includes the pinion shaft 25 and the rack shaft 26 described above. The rack shaft 26 has a columnar shape that extends in the vehicle width direction of the vehicle body 1 described above. Therefore, the axial direction (length direction) X of the rack shaft 26 coincides with the vehicle width direction. The rack shaft 26 is accommodated in the above-described lean hose 11 and extends parallel to the lean hose 11 (see also FIG. 1). At a plurality of locations (for example, both end portions) in the axial direction X of the rack shaft 26, an annular (may be interrupted) bush 27 between the outer peripheral surface of the rack shaft 26 and the inner peripheral surface of the lean hose 11. The lean hose 11 supports the rack shaft 26 via the bush 27 so as to be linearly movable (slidable) in the axial direction X.

In the middle of the outer peripheral surface of the rack shaft 26 in the axial direction X, rack teeth 28 that mesh with the pinion 24 provided on the pinion shaft 25 are formed along the axial direction X. A variable gear ratio in which the interval between adjacent rack teeth 28 is different for each region may be applied to the rack shaft 26.
The rack teeth 28 and the pinion 24 constitute a rack and pinion mechanism. Therefore, the steering device 20 is a rack and pinion type steering device.

  The rotation of the steering shaft 21 (pinion shaft 25) accompanying the steering of the steering wheel 8 is converted into a reciprocating linear movement in the axial direction X of the rack shaft 26 by the rack teeth 28 and the pinion 24. When the rack shaft 26 moves in the axial direction X, the rack shaft 26 rubs against the inner peripheral surface of the bush 27. Further, the rack shaft 26 is accommodated in the lean hose 11 both in a stationary state and in a moving state.

  One joint member 30 is provided at each end of the rack shaft 26 in the axial direction X. The joint member 30 may be provided integrally with the rack shaft 26 or may be detachably attached to the rack shaft 26 as a single component. Each joint member 30 includes a base portion 31, two arm portions 32 extending parallel to the outside of the rack shaft 26 along the axial direction X from the base portion 31, and tip ends (base portions) of the two arm portions 32. It integrally includes a shaft portion 33 laid between the end portion on the side opposite to the portion 31 side (see also FIGS. 3 and 4 described later).

The steering mechanism 23 further includes a link arm 35 and a tie rod 36. Each of the link arm 35 and the tie rod 36 is provided on both ends of the rack shaft 26, and one pair exists in total.
The link arm 35 has a vertically long bar shape, and an upper end portion 35 </ b> A forming one end portion of the link arm 35 is branched into two branch portions 37. In addition, each link arm 35 may incline back and forth or right and left with respect to the vertical direction. In each link arm 35, the two branch portions 37 extend in parallel along the longitudinal direction of the link arm 35, and a long hole 38 that is long in the longitudinal direction is formed between the branch portions 37. ing. The tips (the upper ends in FIG. 2) of these branch portions 37 may or may not be connected to each other. In this embodiment, since the tips of these branch portions 37 are not connected, the long hole 38 between these branch portions 37 is formed in a U-shape notched from the upper end of the link arm 35, and the link arm The upper end of 35 is opened upward. When the tips of the branch portions 37 are connected to each other (for example, via another part), the long holes 38 between the branch portions 37 have a substantially elliptical shape that is long in the longitudinal direction. .

  The upper end portion 35A of the link arm 35 is connected to the joint member 30 on the same side in the vehicle width direction (same as the axial direction X described above) in the rack shaft 26. Specifically, as shown in FIG. 3, each shaft portion 33 of the joint member 30 is fitted into the elongated hole 38 between the two branch portions 37 in the upper end portion 35 </ b> A of the link arm 35 so as to be fitted from above. The link arm 35 is connected from the lower side to the joint member 30 on the same side in the vehicle width direction (see the broken line arrow in FIG. 3). The lean hose 11 (see FIG. 2) is appropriately formed with holes and cutouts that allow the upper end portion 35A of the link arm 35 to pass through the lean hose 11 and connect to the joint member 30.

  Here, referring to FIG. 2, in the joint member 30 at both ends (in the axial direction X) of the rack shaft 26, the shaft portion 33 is loosely fitted in the long hole 38 and is long in the long hole 38. It can move in the longitudinal direction of the hole 38 (longitudinal direction of the link arm 35). That is, the upper end portion 35A of each link arm 35 and the axial end portion of the rack shaft 26 (the end portion in the axial direction X, specifically, the joint member 30) are connected with play.

In the middle of the link arm 35 in the vertical direction (between the above-described upper end portion 35A as one end portion and the lower end portion 35B as the other end portion, more specifically in the substantially central position in the vertical direction) A shaft-like fulcrum 39 extending in the direction is provided.
FIG. 4 is a diagram showing in detail the main part of FIG.
With respect to the fulcrum 39, referring to FIG. 4, the vehicle body 1 and the left and right steered wheels 22 are connected by a shock absorber 40 and a spring 41 extending vertically. The vehicle body 1 is provided with a strut house 42 that is connected to the upper end portion 40A of the shock absorber 40 and accommodates the spring 41. The strut house 42 is a part of the vehicle body 1. The fulcrum 39 is connected to the vehicle body 1 (here, as an example, the strut house 42), and is supported by the vehicle body 1 so as to be rotatable.

  Returning to FIG. 2, each link arm 35 can swing around a fulcrum 39. Specifically, when the vehicle body 1 is viewed from the front, each link arm 35 can swing both clockwise and counterclockwise about the fulcrum 39 (see the thick arrow in FIG. 2). For example, in FIG. 2, when the link arm 35 swings clockwise, the upper end portion 35A of the link arm 35 moves to the right side, and the lower end portion 35B of the link arm 35 moves to the left side. On the other hand, in FIG. 2, when the link arm 35 swings counterclockwise, the upper end portion 35A of the link arm 35 moves to the left side, and the lower end portion 35B of the link arm 35 moves to the right side. In addition, in each link arm 35, movements other than swinging around the fulcrum 39 are restricted, so that each link arm 35 can only swing.

Further, the lower end portion 35B of each link arm 35 is located on the inner side (center side of the vehicle body 1) with respect to the steered wheels 22 on the same side (left side or right side of the vehicle body 1) in the vehicle width direction. That is, the pair of link arms 35 are located between the pair of left and right steered wheels 22.
The tie rod 36 is installed between the lower end portion 35B of the link arm 35 on the same side in the vehicle width direction and the steered wheels 22 located outside the lower end portion 35B in the vehicle width direction. The tie rod 36 is connected to the lower end portion 35B of the link arm 35 and the steered wheel 22 via a universal joint 43 such as a ball joint. The tie rod 36 is connected to the steered wheel 22 at a position shifted from the center of rotation of the steered wheel 22.

  Thus, each of the both ends of the rack shaft 26 is connected to the steered wheel 22 via the link arm 35 and the tie rod 36. In this case, as described above, when the steering wheel 8 is rotated and the rack shaft 26 is moved in the axial direction X, the link arms 35 connected to both ends of the rack shaft 26 are moved along with the movement of the rack shaft 26. And swing around the fulcrum 39. As a result, the tie rod 36 connected to the lower end portion 35B of each link arm 35 pulls the steered wheels 22 inward in the vehicle width direction or pushes them outward in the vehicle width direction. Steer in the direction of rotation (steering direction).

  For example, in FIG. 2, when the rack shaft 26 moves to the right side (right side in FIG. 2) with the rotation of the steering wheel 8, the link arm 35 swings clockwise, as described above. 35A moves to the right side, and the lower end 35B of the link arm 35 moves to the left side. Accordingly, the left steered wheel 22 in FIG. 2 is pushed to the left by the tie rod 36 connected to the lower end portion 35B of the left link arm 35, and the right steered wheel 22 in FIG. The tie rod 36 connected to the lower end 35B is drawn to the left side. Thereby, the left and right steered wheels 22 are steered in the same direction.

  On the contrary, in FIG. 2, when the rack shaft 26 moves to the left side (left side in FIG. 2) with the reverse rotation of the steering wheel 8, the link arm 35 swings counterclockwise. The upper end 35A of the link arm 35 moves to the left, and the lower end 35B of the link arm 35 moves to the right. As a result, the left steered wheel 22 in FIG. 2 is drawn to the right by the tie rod 36 connected to the lower end portion 35B of the left link arm 35, and the right steered wheel 22 in FIG. It is pushed to the right by a tie rod 36 connected to the lower end 35B. Thereby, the left and right steered wheels 22 are steered in the same direction (opposite direction).

  Thus, in the steering device 20, the rack shaft 26 moves in the axial direction X with the rotation of the steering wheel 8, and each link arm 35 swings (with the fulcrum 39 as the center) as the rack shaft 26 moves. By moving, the tie rod 36 is moved and the steered wheels 22 are steered. That is, in the steering device 20, the steered wheels 22 can be steered by transmitting a load from the rack shaft 26 to each tie rod 36 by a link mechanism using the link arm 35.

  Here, referring to FIG. 1, the rack shaft 26 that is relatively bulky in the steering device 20 is housed inside the lean hose 11 that is a part of the vehicle body 1. That is, main components (rack shaft 26) of the steering device 20 are mounted in the passenger compartment 4. This avoids interference between the engine 5 and the transmission 6 in the engine room 3 and the steering device 20 (particularly, the rack shaft 26). Therefore, the steering device 20 can be designed without considering interference with the engine 5 and the transmission 6. That is, it is possible to provide the steering device 20 that can avoid the interference with the engine 5 and the transmission 6 as much as possible and can improve the degree of freedom in design. Furthermore, since the steering device 20 is disposed outside the engine room 3, the thermal conditions (high temperature resistance, etc.) required for the steering device 20 are alleviated. In this respect as well, the design of the steering device 20 is reduced. The degree of freedom can be improved.

Further, when the vehicle body 1 collides from the front side, the impact at that time is mitigated in the engine room 3, so that it is not directly transmitted to the steering device 20 (particularly, the steering shaft 21) in the vehicle compartment 4. This is advantageous in that the impact is less likely to be transmitted to the driver holding the steering wheel 8.
Further, since the steering device 20 does not exist in the engine room 3, the degree of freedom in designing, packaging, and layout of the engine 5 and the transmission 6 in the engine room 3 can be improved.

  Moreover, since the lean hose 11 is generally a metal pipe, when it exists as a single unit, there is a possibility that it will vibrate (resonate) at some timing. In order to suppress the resonance of the lean hose 11, it is necessary to increase the rigidity of the lean hose 11 by increasing the thickness of the lean hose 11. However, if the thickness of the lean hose 11 is increased, the cost of the lean hose 11 is increased. Will increase. Therefore, since the lean hose 11 is reinforced by arranging the rack shaft 26 inside the lean hose 11, the rigidity of the lean hose 11 can be easily increased and the resonance of the lean hose 11 can be reduced.

  2, as described above, the upper end portion 35A of each link arm 35 and the axial end portion (joint member 30) of the rack shaft 26 are connected with play. Therefore, when the link arm 35 swings, a force in a direction different from the axial direction X (for example, a direction orthogonal to the axial direction X) acts on the rack shaft 26 (joint member 30) from the link arm 35. This can prevent the smooth axial movement of the rack shaft 26 from being hindered.

  The steering device 20 may be an electric power steering device including a motor 51 and a speed reducer 52 for assisting steering of the steering wheel 8. The speed reducer 52 includes a worm shaft 53 connected to an output shaft (not shown) of the motor 51 and a worm wheel 54 that can rotate integrally with the steering shaft 21 while meshing with the worm shaft 53. Furthermore, the steering device 20 may include an ECU (Electronic Control Unit) for controlling the driving of the motor 51 (not shown). In this case, the ECU generates a necessary driving force for the motor 51 based on the rotational torque (steering torque) of the steering wheel 8 and the vehicle speed (traveling speed of the vehicle body 1).

The driving force generated by the motor 51 is decelerated between the worm shaft 53 and the worm wheel 54 and then transmitted to the steering shaft 21 (in other words, the steering wheel 8). Thereby, an assisting force (assist force) is given to the steering of the steering wheel 8.
In FIG. 2, the worm wheel 54 (the entire motor 51 and reduction gear 52) is attached to the lower end portion of the steering shaft 21 (the portion farther from the steering wheel 8 than the meshing portion between the pinion 24 and the rack teeth 28). However, it may be attached closer to the steering wheel 8 than the meshing portion.

Thus, the steering force of the steering wheel 8 can be assisted by transmitting the driving force generated by the motor 51 to the steering wheel 8 after being decelerated by the reduction gear 52.
Further, when the steering device 20 is configured as an electric power steering device, the ball nut mechanism 60 shown in FIG. 5 may be included as another configuration for assisting the steering of the steering wheel 8.

Referring to FIG. 5, the ball nut mechanism 60 includes a screw shaft portion 61, a ball nut 62, a bearing 63, a ball 64, and a motor 65.
The screw shaft portion 61 is provided in the middle of the rack shaft 26 (here, a region where the rack teeth 28 are avoided in the axial direction X). The screw shaft portion 61 may be integrally formed with the rack shaft 26. The screw shaft portion 61 is a spiral groove (thread portion) centering on the axis center of the rack shaft 26 in the rack shaft 26, and is formed in the axial direction X on the outer peripheral surface of the rack shaft 26.

  The ball nut 62 is an annular body and has a predetermined length in the axial direction. The ball nut 62 is integrally provided with a main body portion 66 and an extending portion 67. The main body portion 66 and the extending portion 67 are both annular bodies, and are arranged coaxially in a state of being aligned in the axial direction. In FIG. 5, an extending portion 67 is disposed on the left side of the main body portion 66. The outer diameter of the main body portion 66 and the outer diameter of the extending portion 67 are substantially the same, but the inner diameter of the main body portion 66 is smaller than the inner diameter of the extending portion 67. A threaded portion 68 is formed on the inner peripheral surface of the main body portion 66. The screw portion 68 is a spiral groove centered on the axial center of the main body portion 66, and is formed over the entire inner peripheral surface of the main body portion 66. The ball nut 62 is disposed in the lean hose 11 together with the rack shaft 26, is externally fitted to the screw shaft portion 61 of the rack shaft 26, and is coaxial with the rack shaft 26 and the lean hose 11. . In this state, the screw portion 68 of the main body portion 66 of the ball nut 62 faces the screw shaft portion 61 from the outside in the radial direction.

  The bearing 63 is an annular ball bearing and includes an outer ring 63A, an inner ring 63B, and a rolling element 63C. The bearing 63 is disposed in the lean hose 11. The outer circumferential surface of the outer ring 63A is fitted into the inner circumferential surface of the lean hose 11, and the inner circumferential surface of the inner ring 63B is fitted into the outer circumferential surface of the main body 66 of the ball nut 62. For example, the outer ring 63 </ b> A is fitted into a groove 69 formed on the inner peripheral surface of the lean hose 11, whereby the bearing 63 is fixed at a fixed position on the inner peripheral surface of the lean hose 11. Thereby, the ball nut 62 is rotatably supported by the lean hose 11 via the bearing 63 at a fixed position in the axial direction X.

  The ball 64 is a sphere. A large number of balls 64 are interposed between the threaded portion 68 of the main body 66 of the ball nut 62 and the threaded shaft portion 61, and are fitted in the respective grooves of the threaded portion 68 and the threaded shaft portion 61. Thereby, the ball nut 62 is screw-coupled via the screw shaft portion 61 and the ball 64. Therefore, in the ball nut mechanism 60, when the ball nut 62 is rotated, the relative coupling position between the ball nut 62 and the screw shaft portion 61 changes in the axial direction X of the rack shaft 26. Thereby, the ball nut mechanism 60 can displace the rack shaft 26 in the axial direction X.

  For example, when the ball nut 62 is rotated in one direction as viewed from the axial direction X, the rack shaft 26 slides to the left, and when the ball nut 62 is rotated in the reverse direction, the rack shaft 26 slides to the right. Thus, the ball nut mechanism 60 converts the rotation of the ball nut 62 into a reciprocating linear movement in the axial direction X of the rack shaft 26. The ball nut mechanism 60 is provided with a non-rotating mechanism (not shown) for preventing the rack shaft 26 from rotating about the axis as the ball nut 62 rotates.

  The motor 65 includes a rotor 70 and a stator 71. The rotor 70 is provided over the entire circumferential direction on the outer peripheral surface of the extending portion 67 of the ball nut 62. Thereby, the rotor 70 is integrated with the ball nut 62. The stator 71 is fixed to the inner peripheral surface of the lean hose 11 and surrounds the rotor 70 in a non-contact manner. The motor 65 is electrically connected to the ECU (not shown) described above. The motor 65 is driven by receiving a command from the ECU and being supplied with electric power from the vehicle body 1. In the driven motor 65, the rotor 70 rotates with the ball nut 62 in one direction or the reverse direction described above. As a result, the relative coupling position between the ball nut 62 and the screw shaft portion 61 changes as described above, so that the rack shaft 26 is displaced in the axial direction X. Accordingly, the rack shaft 26 is moved by being assisted by the driving force of the motor 65 in addition to the rack shaft 26 being moved by the driver rotating the steering wheel 8. That is, the ball nut mechanism 60 assists the movement of the rack shaft 26 in the axial direction X. Thereby, steering of the steering wheel 8 can be assisted.

The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims.
For example, as a configuration for assisting the movement of the rack shaft 26 other than the ball nut mechanism 60, an endless belt (not shown) connected to the rack shaft 26 is rotated forward or reverse by a motor (not shown), thereby The shaft 26 may be moved in the axial direction X.

  In addition, various design changes can be made within the scope of matters described in the claims.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle body, 8 ... Steering wheel, 11 ... Lean hose, 20 ... Steering device, 22 ... Steering wheel, 24 ... Pinion, 25 ... Pinion shaft, 26 ... Rack shaft, 28 ... Rack tooth, 35 ... Link arm, 35A ... Upper end part, 35B ... Lower end part, 36 ... Tie rod, 39 ... Support point, 51 ... Motor, 52 ... Reduction gear, 60 ... Ball nut mechanism, 61 ... Screw shaft part, 62 ... Ball nut, 64 ... Ball, 65 ... Motor, X ... Axial direction

Claims (5)

A rack and pinion type steering apparatus comprising a pinion shaft connected to a steering member and a rack shaft having rack teeth meshing with the pinion of the pinion shaft,
The rack shaft is accommodated inside a tubular lean hose that is a part of a vehicle body, and is supported by the lean hose so as to be movable in the axial direction.
A tie rod connected to the steered wheels;
A steering device comprising: a link arm connected to an axial end of the rack shaft and the tie rod, and for turning a steered wheel as the rack shaft moves. The link arm is
One end connected to the axial end of the rack shaft, the other end connected to the tie rod, and a fulcrum located between the one end and the other end and connected to the vehicle body,
The steering apparatus according to claim 1, wherein the steering apparatus is swingable about the fulcrum as the rack shaft moves.   The steering apparatus according to claim 2, wherein one end portion of the link arm and an axial end portion of the rack shaft are connected with play. A motor for generating a driving force for steering the steering member;
The steering apparatus according to claim 1, further comprising a speed reducer that decelerates the driving force generated by the motor and transmits the driving force to a steering member.   A screw shaft portion provided in the rack shaft, a ball nut that is externally fitted to the screw shaft portion and is screw-coupled to the screw shaft portion via a ball, and a motor that rotates the ball nut, The ball nut mechanism for assisting the movement of the rack shaft in the axial direction by changing a relative coupling position of the ball nut and the screw shaft portion. The steering device according to any one of?

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