JP2007153176A - Steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steering device having a boot of long lifetime. <P>SOLUTION: The rack-and-pinion type steering device has a pinion shaft rotated by steering, and a rack shaft 8 which is engaged with the pinion shaft and moved in the axial direction Y1 by the rotation of the pinion shaft. The rack shaft 8 is supported by a cylindrical housing 9 movably in the axial direction, and a tie rod 11 is connected to both ends of the rack shaft 8 via a ball joint 10, respectively. The end 9a of the housing 9, the end 8a of the rack shaft 8, a cylindrical boot 14 for covering a part of the ball joint 10 and the tie rod 11, and a sleeve 15 with one end 15a thereof held by the housing 9 to cover the rack shaft 8 inward of the radial direction X1 of the boot 14 are provided on both ends of the rack shaft 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a steering device for an automobile or the like.

A rack-and-pinion steering device is known as a steering device for automobiles and the like. This rack and pinion type steering device includes a pinion shaft that rotates by steering, and a rack shaft that meshes with the pinion shaft and moves in the axial direction by the rotation of the pinion shaft. The rack shaft is supported in a cylindrical housing so as to be movable in the axial direction, and both ends of the rack shaft protrude from the housing. Further, tie rods are respectively connected to both ends of the rack shaft via ball joints, and the end of the rack shaft and the ball joint are covered with a cylindrical bellows-like boot. (For example, refer to Patent Document 1).
Utility Model No. 2549360

However, in the invention described in Patent Document 1, the boot is deformed by being exposed to a high temperature, and the boot is rubbed against the sliding portion of the ball joint or is caught in the rack shaft and the housing when the rack shaft moves in the axial direction. It may be damaged.
Such a problem is not limited to a rack and pinion type steering device, but relates to a steering device in general having a steered shaft that moves in the axial direction by steering.

  The present invention has been made based on such a background, and an object thereof is to provide a steering apparatus having a long-life boot.

  To achieve the above object, the present invention provides an end (8a) of a rack shaft (8) protruding from an end (9a) of a cylindrical housing (9), and a ball connected to the end of the rack shaft. A bellows-like boot (14) for covering the joint (10), and a sleeve (15, 150) for restricting contact between the boot and the rack shaft by covering the rack shaft inwardly in the radial direction (X1) of the boot. ), And one end (15a, 150b) of the sleeve is held at the end of the housing.

According to the present invention, by providing a sleeve between the rack shaft and the boot, contact between the boot and the rack shaft and contact between the boot and the ball joint can be prevented. As a result, it is possible to prevent the boot from being damaged by the contact, so that it is possible to extend the life of the boot.
Further, when the sleeve is an elastic body containing synthetic resin or synthetic rubber, it is possible to prevent the boot from deteriorating due to contact between the boot and the sleeve, and to extend the life of the boot.

  In the above description, the alphanumeric characters 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.

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a partial cross-sectional view schematically showing a schematic configuration of a rack and pinion type steering apparatus 1 according to an embodiment of the present invention. Referring to FIG. 1, a steering device 1 includes a steering shaft 3 connected to a steering member 2 such as a steering wheel, a pinion shaft 5 connected to the steering shaft 3 via an intermediate shaft 4, and a pinion shaft 5. The rack 7 meshes with the formed pinion 6 and includes a rack shaft 8 as a steered shaft extending in the left-right direction of the automobile.

The rack shaft 8 is supported by a cylindrical housing 9 through a plurality of bearings (not shown) so as to be linearly reciprocable. Both end portions 8 a of the rack shaft 8 protrude from the side ends of the housing 9, and each end portion 8 a is connected to one end of the tie rod 11 via the ball joint 10. A steering wheel 13 is connected to the other end of the tie rod 11 via a knuckle arm 12.
By operating the steering member 2, the steering shaft 3 rotates. The rotation of the steering shaft 3 is converted into a linear reciprocating motion of the rack shaft 8 in the left-right direction of the vehicle body via the pinion 6 and the rack 7. Thereby, steering of the steered wheel 13 is achieved.

FIG. 2 is a partial cross-sectional view showing the end 8a of the rack shaft 8 in FIG. 1 and the vicinity thereof. In FIG. 2, only the end portion 8a of one rack shaft 8 and the vicinity thereof are shown, but the end portion 8a of the other rack shaft 8 and the vicinity thereof also includes the end portion 8a of one rack shaft 8 and the vicinity thereof. It has the same configuration as its vicinity.
Referring to FIG. 2, at both ends of rack shaft 8, tubular boot 14 covering end 9 a of housing 9, end 8 a of rack shaft 8, ball joint 10 and tie rod 11, boot 14 A cylindrical sleeve 15 that covers the end 8a of the rack shaft 8 is provided inward in the radial direction X1.

  The boot 14 is formed of a synthetic resin such as a polyolefin-based elastomer, for example. One end of the boot 14 is fitted to the outer periphery 16 of the end 9 a of the housing 9, and the other end of the boot 14 is fitted to the tie rod 11. . In addition, annular fastening bands 17 are provided on the outer circumferences of one end and the other end of the boot 14, respectively, and the boot 14 is fastened to the housing 9 and the tie rod 11 without a gap by the fastening band 17. This prevents foreign matter such as pebbles and rainwater from entering the boot 14 and suppresses the end 9a and the like of the housing 9 from being damaged or rusted.

Further, an intermediate portion between one end and the other end of the boot 14 is formed in a bellows shape. Thereby, for example, even when the rack shaft 8 linearly reciprocates in the left-right direction of the vehicle body, the boot 14 can flexibly expand and contract to follow the movement of the rack shaft 8.
The sleeve 15 is disposed inside the boot 14 in the radial direction X1, and is formed of a synthetic resin such as polyacetal or a synthetic rubber, for example. One end 15a of the sleeve 15 is fixed, for example, by being press-fitted into the inner periphery 18 of the end 9a of the housing 9. The other end of the sleeve 15 extends in the axial direction Y <b> 1 from the end 9 a of the housing 9 toward the ball joint 10, and covers the end 8 a of the rack shaft 8.

  Thus, since the sleeve 15 covers the end portion 8a of the rack shaft 8, when the boot 14 is deformed by being exposed to a high temperature, the boot 14 is worn by rubbing against the rack shaft 8 and the ball joint 10. Further, it is possible to prevent the boot 14 from being caught between the rack shaft 8 and the housing 9 and being damaged when the rack shaft 8 is linearly reciprocated in the left-right direction of the vehicle body.

Since the boot 14 is most easily deformed and damaged at the axial center, the sleeve 15 preferably extends to the axial center of the boot 14 to cover the rack shaft 8.
As described above, according to this embodiment, the sleeve 15 that covers the end portion 8a of the rack shaft 8 is provided inside the boot 14 in the radial direction X1. As a result, even if the boot 14 is exposed to a high temperature and deformed, the boot 14 is worn by rubbing against the rack shaft 8 or the ball joint 10, or the rack shaft 8 is moved when the rack shaft 8 is linearly reciprocated in the left-right direction of the vehicle body. It is possible to prevent the boot 14 from being caught between the housing 9 and the housing 9 and being damaged. Therefore, the life of the boot 14 can be extended.

Further, since the sleeve 15 is made of synthetic resin or synthetic rubber, the boot 14 can be prevented from being deteriorated due to contact between the boot 14 and the sleeve 15 and the life of the boot 14 can be extended.
FIG. 3 is a partial cross-sectional view showing the end 8a of the rack shaft 8 according to another embodiment of the present invention and the vicinity thereof. In FIG. 3, the same components as those shown in FIG. 2 described above are denoted by the same reference numerals as those in FIG.

  Referring to FIG. 3, this embodiment is mainly different from the embodiment of FIG. 2 in that sleeve 150 and boot 14 are fitted on outer periphery 16 of end portion 9a of housing 9, and sleeve 150 and That is, the boot 14 is fastened together by the fastening band 17. The sleeve 150 has a small diameter portion 150 a and a large diameter portion 150 b that are concentrically connected. The large diameter portion 150 b is fitted on the outer periphery of the end portion 9 a of the housing 9, and the small diameter portion 150 a covers the rack shaft 8. ing.

According to this embodiment, the same effect as the embodiment shown in FIG. 2 can be obtained. Further, the sleeve 150 and the boot 14 are fastened together with the end 9 a of the housing 9 by the fastening band 17, so that the step of pressing the sleeve 150 into the housing 9 can be omitted.
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, the sleeve may be fixed to the housing not only by press-fitting or fastening with a fastening band, but also by screwing, bonding, or the like.

  Further, the cross-sectional shape of the sleeve may be a square shape in addition to a circular shape, or a substantially D shape or a substantially Y shape that is similar to the outer diameter of the rack shaft.

1 is a partial cross-sectional view schematically showing a schematic configuration of a rack-and-pinion steering device according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional view showing an end of a rack shaft in FIG. 1 and its vicinity. It is a partial cross section figure which shows the edge part of rack shaft concerning another embodiment of this invention, and its vicinity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Steering device, 8 ... Rack shaft, 8a ... End part (end part of rack shaft), 9 ... Housing, 9a ... End part (end part of housing), 10 ... Ball joint, 14 ... boot, 15 ... sleeve, 15a ... one end (one end of the sleeve), 150b ... large diameter part (one end of the sleeve), X1 ... radial direction

Claims (2)

A bellows-shaped boot for covering the end of the rack shaft protruding from the end of the cylindrical housing, and a ball joint connected to the end of the rack shaft;
A sleeve that regulates the contact between the boot and the rack shaft by covering the rack shaft radially inward of the boot,
One end of the sleeve is held by the end of the housing.   The steering apparatus according to claim 1, wherein the sleeve is an elastic body including synthetic resin or synthetic rubber.

Images