JP2013086528A - Rack and pinion type steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rack and pinion type steering device capable of keeping a preload force when advances roughly fixed, keeping the magnitude of adjustment backlash roughly fixed without increasing it, and preventing rattling noise even when separation force exceeds the preload force, in a rack and pinion type steering device.SOLUTION: The rack and pinion type steering device includes: a rack guide to be in slidable contact with a rack shaft; an elastic member for pressing the rack guide to the rack shaft; a conversion mechanism for changing torque to pressing force; a torque generation member for generating the torque; and a rotating direction limiting member for limiting rotation to one direction.

Description

  The present invention relates to a rack and pinion type steering device for a vehicle.

  A force called reverse input is input to a rack-and-pinion type steering device for a vehicle, for example, because a tire passes through unevenness on a road surface. Due to the reverse input, the rack and the pinion are engaged with each other, and a force that separates the rack and the pinion in the sliding direction of the rack guide works. When the separation force at this time is larger than the spring pre-pressure that presses the rack and the pinion, the rack and the pinion are separated from each other, and a gap is formed at the engaging portion of the rack and the pinion. When this gap is restored, a collision occurs between the rack and the pinion tooth surface. If the clearance is large, the collision sound becomes loud, which causes a problem with hearing. In order to prevent rattle audibility problems, it is necessary to make the preload larger than the reverse input load, and to reduce the gap created on the tooth surface when the separation force due to the reverse input load is greater than the preload. is important. In general, when a rack and a pinion are used for a long period of time, wear occurs at a meshing portion of the rack and the pinion, so that the preload by the spring is reduced and the adjustment backlash is increased.

  As a prior art for preventing the rattle noise, there is a technique described in Patent Document 1 in FIG. In addition to the coil spring that is the elastic member 24, the torsion return force of the mainspring spring 25 is preloaded through the mechanism of the protrusion 21 and the groove cam 22 to load. For this reason, even if wear occurs during long-term use and the play between the rack and the pinion tooth surface increases, the preload does not decrease.

JP 2010-210062 A

  However, when the pre-pressure exceeds the separation force, the groove cam 22 can rotate in a direction that separates the rack and the pinion and creates a gap in the tooth surface, so that an increase in play due to wear cannot be prevented. For this reason, there is a problem that rattle noise cannot be prevented when the separation force exceeds the preload.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a rack and pinion type steering device that can prevent rattle noise even when the separation force exceeds the preload.

  To achieve the above object, the present invention provides a rack and pinion type steering device, wherein the rack and pinion type steering device includes a rack guide slidably contacting the rack shaft, and the rack guide is mounted on the rack shaft. It has an elastic member for pressing, a conversion mechanism that converts a rotational force into a pressing force, a rotational force generating member for generating a rotational force, and a rotational direction limiting member that restricts rotation in one direction. To do.

  In the present invention, the pressing force is generated by the conversion mechanism that converts the rotational force into the pressing force and the rotational force generating member that rotates the conversion mechanism. In addition, this conversion mechanism cannot be rotated in the direction in which the rack and pinion are separated by the one-way clutch or ratchet to create a gap in the tooth surface, but can be rotated only in the direction in which the rack guide is preloaded. As a result, not only the preload when wear progresses can be kept substantially constant, but also the size of the adjustment backlash can be kept almost constant without being increased. For this reason, rattle noise can be prevented even when the separation force exceeds the preload.

Partial sectional view of a rack and pinion type steering device according to the present invention Sectional view of the portion where the rotational force is generated in FIGS. 1 and 3 Partial sectional view of a rack and pinion type steering device according to the present invention The schematic diagram which shows schematic structure of the ratchet part of FIG. 1 is a schematic diagram showing a schematic configuration of a rack and pinion type steering device according to the present invention. Partial sectional view of a conventional rack and pinion type steering device

Hereinafter, a rack and pinion type steering apparatus 1 according to the present invention will be described with reference to the drawings. As shown in FIG. 5, the rack-and-pinion type steering device 1 of the present embodiment includes a steering member 2 such as a steering wheel.
A steering shaft 3 connected to the steering shaft 3, an intermediate shaft 5 connected to the steering shaft 3 via a universal joint 4, a pinion shaft 7 connected to the intermediate shaft 5 via a universal joint 6, and a pinion shaft 7 It has a rack 8a that has a rack 8a that meshes with a pinion 7a provided in the vicinity of the end portion, and that serves as a steered shaft extending in the left-right direction of the automobile. The pinion shaft 7 and the rack shaft 8 constitute a rack and pinion mechanism A as a steering mechanism.

The rack shaft 8 is supported in a rack housing 9 fixed to the vehicle body through a plurality of bearings (not shown) so as to be linearly reciprocable along the axial direction Z1. Both ends of the rack shaft 8 are rack housings 9
The tie rod 10 is coupled to each end portion. Each tie rod 10 is connected to a corresponding steered wheel 11 via a corresponding knuckle arm (not shown). When the steering member 2 is operated and the steering shaft 3 is rotated, this rotation is converted into a linear motion of the rack shaft 8 along the left-right direction of the automobile by the pinion 7a and the rack 8a. Thereby, the turning of the steered wheel 11 is achieved.

  As shown in FIGS. 1 and 2, the rack-and-pinion steering device 1 includes a rack guide 18 that slides on the rack shaft 8 and an elastic member that presses the rack guide 18 against the rack shaft 8. 24, a disc spring, a conversion mechanism 26 that converts a rotational force into a pressing force, a coil spring that is a rotational force generating member 27 for generating a rotational force, and a rotational direction restricting member 28 that restricts rotation in one direction. And a one-way clutch. In FIG. 1, a rotational force is generated by a coil spring, and rotation is converted into linear motion by a male screw portion 26 a 1 installed on the outer periphery of the conversion component 26 a constituting the conversion mechanism 26 and a female screw portion 17 a 1 installed on the inner periphery of the housing 17. Is done. The preload on the rack shaft 8 of the rack guide 18 is adjusted by rotating the spring adjusting portion 29, and after the adjustment, the nut 30 is tightened and fixed to the cover 19 by friction. Further, the rotation direction is limited only to the direction in which the preload is applied by the one-way clutch.

  Next, another embodiment of the rack and pinion type steering apparatus 1 according to the present invention will be described with reference to the drawings. Note that items described in the previous embodiment are omitted. As shown in FIGS. 3 and 2, the rack and pinion type steering apparatus 1 of the present embodiment uses a coil spring as an elastic member 24 for pressing the rack guide 18 against the rack shaft 8, and rotates. A ratchet portion is provided as the rotation direction restricting member 28 for restricting in one direction. As for the ratchet portion, a schematic diagram showing a schematic configuration of FIG. 4 shows a rough configuration. As shown in FIG. 3, a ratchet gear portion 26b installed on the outer periphery of the conversion component 26a constituting the conversion mechanism 26; By the ratchet pawl portion 31, the rotation direction is limited only to the direction in which the preload is applied.

  As described above, in the present invention, the pressing force is generated by the conversion mechanism that converts the rotational force into the pressing force and the rotational force generating member that rotates the conversion mechanism. In addition, this conversion mechanism cannot be rotated in the direction in which the rack and pinion are separated by the one-way clutch or ratchet to create a gap in the tooth surface, but can be rotated only in the direction in which the rack guide is preloaded. As a result, not only the preload when wear progresses can be kept substantially constant, but also the size of the adjustment backlash can be kept almost constant without being increased. For this reason, rattle noise can be prevented even when the separation force exceeds the preload.

  Moreover, the above-mentioned embodiment shows an example of this invention, Comprising: This invention is not limited to these embodiment. As long as the gist of the present invention is not deviated, the present invention can be applied to other embodiments.

DESCRIPTION OF SYMBOLS 1 Rack and pinion type steering apparatus 2 Steering member 3 Steering shafts 4 and 6 Universal joint 5 Intermediate shaft 7 Pinion shaft 7a Pinion 8 Rack shaft 8a Rack 9 Rack housing 10 Tie rod 11 Steering wheel 17 Housing 17a1 Female thread 18 Rack guide 19 Cover 21 Protrusion 22 Groove cam 24 Elastic member 25 Spring spring 26 Conversion mechanism 26a Conversion part 26a1 Male thread portion 26b, 260b Ratchet gear portion 27 Rotation force generating member 28 Rotation direction limiting member 29 Spring adjustment portion 30 Nut 31, 310 Ratchet pawl stop

Claims (1)

In the rack and pinion type steering apparatus, the rack and pinion type steering apparatus includes a rack guide that is slidably contacted with the rack shaft, an elastic member that presses the rack guide against the rack shaft, and a rotational force. A rack-and-pinion type steering apparatus, comprising: a conversion mechanism for converting to force; a rotational force generating member for generating rotational force; and a rotational direction restricting member for restricting rotation in one direction.

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