JP2006069381A - Rack-and-pinion type steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rack-and-pinion type steering device which improves operability and reduces noises as well. <P>SOLUTION: The rack-and-pinion type steering device comprises a pinion, a rack gearing with the pinion, a rack guide forcing the rack toward the pinion by applying energy, a housing housing the rack guide, a rack guide seat which is interposed between the rack and the rack guide and bears the rack slidably in the direction of the rack, and an elastic member which is disposed between the inner surface of the housing and the outer surface of the rack guide to exert an elastic force that separates the housing and the rack guide apart. The elastic force of the elastic member is greater in the rack direction than in the vertical direction of a vehicle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rack-and-pinion type steering device that achieves both improved operability and reduced noise.

Conventionally, a pinion shaft, a rack shaft that meshes with the pinion shaft, a rack guide that supports the rack shaft, a housing that houses the rack guide, a rack member that covers the rack guide, and a receiving member that slidably receives the rack shaft, and an outer periphery of the rack guide A rack-and-pinion type steering device including a cushioning member interposed between the surface and the inner peripheral surface of the housing, wherein the receiving member and the cushioning member are made into a single unit made of a synthetic resin integral molding. A steering device is known (see, for example, Patent Document 1).
JP 2002-240723 A

  However, in the conventional steering device, the buffer member interposed between the outer peripheral surface of the rack guide and the inner peripheral surface of the housing has an elastic force that separates the outer peripheral surface of the rack guide and the inner peripheral surface of the housing from each other. It occurs uniformly over the entire circumference. Therefore, the outer peripheral surface of the rack guide and the inner peripheral surface of the housing are evenly buffered over the entire periphery, and rattling noise caused by the collision between the rack shaft and the pinion shaft is prevented, but the movement of the rack guide is suppressed. As a result, sliding of the rack shaft is suppressed. As a result, the smooth movement of the rack shaft at the initial stage of steering is deteriorated, resulting in a decrease in operability.

  The present invention has been made to solve such problems, and a main object of the present invention is to provide a rack-and-pinion type steering device that achieves both improved operability and reduced noise.

  An aspect of the present invention for achieving the above object includes a pinion shaft, a rack shaft that meshes with the pinion shaft, a rack guide that urges the rack shaft toward the pinion shaft, and the rack guide. A housing, a rack guide sheet interposed between the rack shaft and the rack guide and slidably receiving the rack shaft in the rack axis direction; an inner peripheral surface of the housing; and an outer peripheral surface of the rack guide; A rack-and-pinion type steering device that includes an elastic member that generates an elastic force that separates the housing and the rack guide from each other. The rack and pinion type steering device is characterized in that the elastic force is smaller than the elastic force in the vehicle vertical direction.

  In this aspect, the vehicle vertical direction is a direction perpendicular to the rack axis direction.

  According to this aspect, the elastic force in the rack axis direction of the elastic member is smaller than the elastic force in the vehicle vertical direction. Accordingly, the rack guide is easily moved in the rack axis direction by reducing the elastic force in the rack axis direction. Therefore, the initial operation of the rack shaft at the initial stage of steering can be facilitated, and the operability of the rack and pinion type steering device can be improved. Further, by increasing the elastic force in the vehicle vertical direction, the rack guide can be reliably suppressed from moving in the vehicle vertical direction, and the rack shaft can be reliably suppressed from moving in the vehicle vertical direction. . Accordingly, noise such as rattling noise generated at the meshing portion of the rack shaft and the pinion shaft can be more reliably prevented, and the noise of the rack and pinion type steering device can be reduced. That is, it is possible to provide a rack and pinion type steering device that realizes improved operability and reduced noise at the same time.

  Further, in this aspect, the elastic member is connected to the rack guide seat, extends between the inner peripheral surface of the housing and the outer peripheral surface of the rack guide, and is convex toward the inner peripheral surface of the housing. It is preferable that the plurality of claw portions are formed in the above-described manner and elastically contact the inner peripheral surface of the housing.

  Furthermore, in this one aspect, two pairs of the claw portions are connected to the rack guide sheet, one pair of the claw portions is connected along the rack axis direction, and the other pair of the claw portions is It is preferable that the elastic forces of the one pair of claws are smaller than the elastic force of the other pair of claws.

  ADVANTAGE OF THE INVENTION According to this invention, the rack and pinion type steering device which implement | achieved the operativity improvement and the noise reduction simultaneously can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. The basic concept of the steering device, the main hardware configuration, the operating principle, the basic control method, and the like are known to those skilled in the art, and thus detailed description thereof is omitted.

  FIG. 1 is a cross-sectional view of a main part showing a rack and pinion type steering apparatus according to an embodiment of the present invention. The rack and pinion type steering device 2 of this embodiment includes a pinion shaft 4. The pinion shaft 4 is connected to the steering wheel via the steering shaft. A rack shaft 6 is engaged with the pinion shaft 4. The rack shaft 6 extends in the left-right direction of the vehicle, and moves to the left and right by the rotational movement of the pinion shaft 4. One end of a tie rod is connected to each end of the rack shaft 6, and a wheel is connected to the other end of each tie rod via a knuckle arm or the like. When the steering wheel is steered, the rotation of the pinion shaft 4 is converted into the left and right movements of the rack shaft 6, and the wheels are steered through tie rods and the like.

  A rack guide 8 is provided on the rack shaft 6. The rack guide 8 slidably supports and guides the rack shaft 6 via the rack guide sheet 10.

  The rack guide 8 has a substantially cylindrical shape, and a U-shaped recess 8 a is formed at an end that supports and guides the rack shaft 6. The rack guide 8 is housed in a rack guide housing chamber 12 a of the housing 12. A predetermined gap Δ is set in the radial direction of the rack guide 8 between the outer peripheral surface of the rack guide 8 and the inner peripheral surface of the housing 12 (the peripheral wall of the rack guide housing chamber 12a). The predetermined gap Δ may be constant along the circumferential direction of the rack guide 8.

  The rack guide 8 is urged toward the rack shaft 6 by a spring 14 in order to ensure proper engagement of the rack shaft 6 with the pinion shaft 4.

  A rack guide sheet 10 interposed between the rack shaft 6 and the rack guide 8 receives the rack shaft 6 so as to be slidable in the rack shaft direction, and is pressed against the rack shaft 6 in a state of being pressed against the rack shaft 6. It plays the role of reducing the sliding friction force between.

  The rack guide sheet 10 is connected to two pairs of claw portions (elastic members) 10 a extending in a gap between the outer peripheral surface of the rack guide 8 and the inner peripheral surface of the housing 12. Each claw portion 10 a has a convex shape such as an R shape toward the inner peripheral surface of the housing 12, and the tip is fitted in a groove portion 8 b formed in the circumferential direction of the rack guide 8. The convex portion of the claw portion 10a is in elastic contact with the inner peripheral surface of the housing. Further, the claw portion 10a is formed of an elastic member such as a resin or a spring. In addition, although two pairs of claw portions 10a are connected to the rack guide sheet 10, the number of claw portions 10a connected to the rack guide sheet 10 may be arbitrary. Moreover, although the rack guide sheet 10 and the claw part 10a are integrally formed, the rack guide sheet 10 and the claw part 10a may be formed separately.

  FIG. 2A is a view showing the shape of the rack guide sheet 10, and is a view of the rack guide sheet 10 shown in FIG. 2B is a cross-sectional view when the rack guide sheet 10 shown in FIG. 2A is cut along a straight line XX ′, and FIG. 2C is the rack guide sheet 10 shown in FIG. Is a cross-sectional view taken along line YY ′.

  With the rack guide sheet 10 attached to the U-shaped recess 8a of the rack guide 8, one pair of claw portions 10a are positioned along the vehicle vertical direction (direction perpendicular to the rack shaft 6). The rack guide sheet 10 extends from the upper end 10b (FIG. 2B). The other pair of claw portions 10a extends from the lower end portion 10c of the rack guide sheet 10 at a position along the rack axis direction (FIG. 2C).

  As shown in FIG. 2A, the width w1 of the claw portion 10a positioned along the vehicle vertical direction is larger than the width w2 of the claw portion 10a positioned along the rack axis direction. Further, the height of the claw portion 10a positioned along the vehicle vertical direction (the amount of protrusion of the claw portion 10a in the housing direction) h1 is larger than the height h2 of the claw portion 10a positioned along the rack axis direction. ing. Thereby, the elastic force F1 of the claw part 10a located along the vehicle vertical direction is larger than the elastic force F2 of the claw part 10a located along the rack axis direction. The elastic forces F1 and F2 of the claw portion 10a increase in proportion to the heights h1 and h2 and the widths w1 and w2 of the claw portion 10a (FIG. 3). Further, the heights h1 and h2 of the claw portion 10a may be adjusted by adjusting the depth of the groove portion 8b of the rack guide 8 (the depth in the radial direction of the rack guide 8). For example, if the depth of the groove portion 8b of the rack guide 8 is increased, the heights h1 and h2 of the claw portion 10b are reduced in a state where the tip of the claw portion 10a is fitted in the groove portion 8b. Further, if the depth of the groove portion 8b is reduced, the heights h1 and h2 of the claw portion 10b are increased in a state where the tip of the claw portion 10a is fitted in the groove portion 8b. As described above, the elastic forces F1 and F2 of the claw portion 10b can be easily adjusted by adjusting the heights h1 and h2 and the widths w1 and w2 of the claw portion 10b and the depth of the groove portion 8b of the rack guide 8. it can.

  For example, although the vehicle moves up and down when traveling on a rough road, the rack guide 8 can be reliably moved in the vehicle vertical direction by increasing the elastic force F1 of the claw portion 10a positioned along the vehicle vertical direction. It is possible to reliably suppress the rack shaft 6 from moving in the vehicle vertical direction. Therefore, abnormal noise such as rattling noise generated at the meshing portion between the rack shaft 6 and the pinion shaft 4 can be more reliably prevented.

  Further, by reducing the elastic force F2 of the claw portion 10a located along the rack axis direction, the rack guide 8 can easily move in the rack axis direction. Therefore, the initial operation of the rack shaft 6 at the initial stage of steering can be facilitated. That is, the rack shaft 6 and the pinion are adjusted by adjusting the elastic force F1 of the claw portion 10a positioned along the vertical direction of the vehicle and the elastic force F2 of the claw portion 10a positioned along the rack axis direction, respectively. The rack guide 8 is easy to move in the rack axis direction while reliably preventing noise such as rattling noise generated at the meshing portion with the shaft 4, and facilitates the initial operation of the rack shaft 6 at the initial stage of steering. Can do. The elastic force F2 of the claw portion 10a located along the rack axis direction is set to be small, but the elastic force F2 of the claw portion 10a located along the rack axis direction is set to be zero. May be.

  Next, the movement of the rack shaft 6 and the rack guide 8 during the steering operation will be described.

  When steering of the steering wheel is started (that is, at the initial stage of steering), the rack shaft 6 is subjected to a force to move along the rack axis direction by the rotational force of the pinion shaft 4. When the rack shaft 6 is about to move, the rack shaft 6, the rack guide 8, and the rack guide sheet 10 are integrated into the rack until the maximum frictional static force between the rack shaft 6 and the rack guide sheet 10 is exceeded. It moves in the moving direction of the shaft 6. At that time, the rack shaft 6, the rack guide 8, and the rack guide sheet 10 receive the elastic force (reaction force) F2 of the claw portion 10a positioned along the rack axis direction. In the above embodiment, the elastic force F2 of the claw portion 10a located along the rack axis direction is set small. As a result, the rack shaft 6, the rack guide 8, and the rack guide seat 10 are easy to move in the moving direction of the rack shaft 6, and the movement of the rack shaft 6 at the initial stage of steering is improved. Therefore, since the rack shaft 6 can start to move as soon as the steering of the steering wheel is started, the steering delay (response delay) at the initial stage of steering is greatly reduced. That is, the operability of the rack and pinion type steering device 2 is improved.

  Furthermore, since the elastic force F1 of the claw portion 10a positioned along the vehicle vertical direction is set large, for example, when the vehicle vertical direction input is applied from the wheel to the rack shaft 6 when traveling on a rough road, etc. The movement of the rack guide 8 in the vehicle vertical direction is suppressed as described above. Therefore, the movement of the rack shaft 6 in the vertical direction of the vehicle is suppressed by the rack guide 8, whereby the rattling noise at the meshing portion between the rack shaft 6 and the pinion shaft 4 is effectively suppressed. That is, the noise of the rack and pinion type steering device 2 can be reduced.

  In the above embodiment, since the rack guide sheet 10 and the claw portion 10a are integrally formed, the number of parts is smaller than that in the configuration using the O-ring for separating the rack guide 8 and the housing 12. And the assembly man-hour can be reduced. In addition, it is possible to improve assemblability because problems such as twisting of the O-ring at the time of assembly and damage due to contact with other parts cannot occur due to the configuration using the O-ring.

  As mentioned above, although the best mode for carrying out the present invention has been described using one embodiment, the present invention is not limited to such one embodiment, and within the scope not departing from the gist of the present invention, Various modifications and substitutions can be made to the above-described embodiment.

  For example, in the above embodiment, one pair of claw portions 10a extends from the upper end portion 10b of the rack guide sheet 10 and the other pair of claw portions 10a extends from the lower end portion 10c of the rack guide sheet 10. The pair of claw portions 10a may extend from the vicinity of the upper end portion 10b of the rack guide sheet 10 (FIG. 4). In this case, the width w and the height h of the claw portion 10a located on the axis L in the vehicle vertical direction are the largest, and the width w and the height h of the claw portion 10a decrease as the distance from the axis L in the vehicle vertical direction increases. ing. Thereby, it is possible to reduce the elastic force of the claw portion 10a in the rack axis direction while increasing the elastic force of the claw portion 10a in the vehicle vertical direction.

  In the above embodiment, two pairs of claw portions 10a are provided between the rack guide 8 and the housing 12, and the elastic force of the claw portions 10a located along the vehicle vertical direction is increased so that the rack axial direction is increased. Is configured to reduce the elastic force of the claw portion 10a positioned along the rail, but an O-ring is provided between the rack guide 8 and the housing 12, and the elastic force of the O-ring portion positioned along the vehicle vertical direction is provided. The elastic force of the O-ring portion positioned along the rack axis direction may be reduced. The elastic force of the O-ring is adjusted, for example, by changing the cross-sectional area of the O-ring.

  The present invention can be used for a rack and pinion type steering device for a vehicle. The appearance, weight, size, running performance, etc. of the vehicle to be mounted are not limited.

It is principal part sectional drawing which shows the rack and pinion type steering device which concerns on one Example of this invention. (A) It is a figure which shows the shape of a rack guide sheet | seat, and is the figure which looked at the rack guide sheet | seat shown in FIG. 1 from A direction. (B) It is sectional drawing when the rack guide sheet | seat shown to Fig.2 (a) is cut | disconnected by the straight line XX '. (C) It is sectional drawing when the rack guide sheet | seat shown to Fig.2 (a) is cut | disconnected by the straight line YY '. It is a figure which shows the elastic force of the nail | claw part of a rack guide sheet. It is a figure which shows the state from which five pairs of nail | claw parts are extended from the upper end part of a rack guide sheet.

Explanation of symbols

2 Rack and pinion type steering device 4 Pinion shaft 6 Rack shaft 8 Rack guide 8a Recessed portion 8b Groove portion 10 Rack guide sheet 10a Claw portion (elastic member)
10b upper end portion 10c lower end portion 12 housing 12a rack guide accommodating chamber 14 spring

Claims (3)

A pinion shaft,
A rack shaft meshing with the pinion shaft;
A rack guide that biases the rack shaft toward the pinion shaft;
A housing for accommodating the rack guide;
A rack guide sheet interposed between the rack shaft and the rack guide and receiving the rack shaft slidably in the rack axis direction;
A rack and pinion type steering apparatus, comprising: an elastic member that is provided between an inner peripheral surface of the housing and an outer peripheral surface of the rack guide and generates an elastic force to separate the housing and the rack guide from each other. Because
The rack and pinion type steering device according to claim 1, wherein the elastic force of the elastic member in the rack axial direction is smaller than the elastic force in the vehicle vertical direction. The rack and pinion type steering device according to claim 1,
The elastic member is connected to the rack guide sheet, extends between an inner peripheral surface of the housing and an outer peripheral surface of the rack guide, and is formed in a convex shape toward the inner peripheral surface of the housing. A rack-and-pinion type steering device comprising a plurality of claw portions elastically contacting an inner peripheral surface. A rack-and-pinion steering device according to claim 2,
Two pairs of the claw portions are connected to the rack guide sheet, one pair of the claw portions is connected along the rack axial direction, and the other pair of the claw portions is along the vehicle vertical direction. A rack-and-pinion type steering device, wherein the elastic forces of the one pair of claws are connected to each other and are smaller than the elastic force of the other pair of claws.

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