JPS621014Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a rack and pinion type steering device for automobiles and the like.

Conventional rack and pinion type steering devices are affected by vibrations transmitted from the road surface through the steering wheels and impact loads during driving, such as the meshing tooth surfaces of the rack and pinion and the parts where the rack guide that meshes with these meshing tooth surfaces and applies preload comes into contact. There was a drawback in that a hitting sound was generated, and when this hitting sound was loud, it caused discomfort to the pilot.

This invention has been made to eliminate the above-mentioned drawbacks, and its object is to provide a rack pinion type steering device which comprises a housing, a pinion shaft rotatably supported within the housing, a rack rod formed with a rack which meshes with the pinion of the pinion shaft, a rack guide made of elastic material fitted into a cylindrical hole provided within the housing, a stopper screwed into the threaded portion at the end of the cylindrical hole, and a spring provided between the stopper and the rack guide to press the rack rod against the pinion via the rack guide, in which the rack guide has a plurality of annular elastic protrusions provided on its outer peripheral surface and an elastic protrusion protruding from a flat portion provided on the end face on the stopper side, thereby preventing the generation of striking sounds while driving, does not cause discomfort to the driver, can reduce processing costs, and is easy to assemble.

An embodiment of this invention will be described below based on the drawings.

In FIG. 1, a pinion shaft 2 is rotatably supported within a housing 1, and a pinion 3 is formed in the center of the pinion shaft 2. As shown in FIG. In the figure, pinion shaft 2
A rack rod 4 is provided above, and a rack 5 that meshes with the pinion 3 is formed on the lower surface of the rack rod 4. A vertical cylindrical hole 6 is provided in the upper part of the housing 1, and a rack guide 7 made of a low-friction, wear-resistant elastic material is fitted into the cylindrical hole 6. A stopper 8 is provided above the rack guide 7, and a spring 9 is provided between the rack guide 7 and the stopper 8. The stopper 8 is screwed into a threaded portion 10 formed at the upper end of the cylindrical hole 6, and a tightening nut 11 is screwed into the stopper 8. A ball bearing 12 and a needle roller bearing 13 are fitted to the left and right ends of the housing 1, respectively, and the pinion shaft 2 is rotatably supported by the ball bearing 12 and the needle roller bearing 13. The lower end surface of the rack guide 7 is formed with a semi-cylindrical concave surface 14 that contacts the cylindrical outer surface of the rack rod 4. As shown in FIGS. 2 and 3, the upper end of the rack guide 7 on the stopper 8 side has a flat surface 15.
and a plurality of conical elastic protrusions 16 equally spaced in the circumferential direction, the tops 17 of the elastic protrusions 16 slightly protrude from the flat part 15 and abut against the lower end surface 18 of the stopper 8. It's becoming like that.
The outer peripheral surface 19 of the rack guide 7 is
A plurality of annular elastic protrusions 20 each having a triangular cross section are arranged in the axial direction of the rack guide 7. The upper surface 21 of each annular elastic protrusion 20 is perpendicular to the axial direction of the rack guide 7, and the lower surface 22 of the protrusion is perpendicular to the axial direction of the rack guide 7. The outer diameter of the annular elastic protrusion 20 is slightly larger than the inner diameter of the cylindrical hole 6 of the housing.

After the rack guide 7 formed as described above is fitted into the cylindrical hole 6 of the housing, a spring 9 is interposed between the rack guide 7 and the stopper 8, and the stopper 8 is screwed into the threaded part 10 of the housing. Assembly is done. When assembling the rack guide 7 into the cylindrical hole 6 of the housing, use the stopper 8 to release the spring 9.
further, the lower end surface 18 of the stopper 8 comes into contact with the top 17 of the elastic projection 16 of the rack guide, and the top 17 of the elastic projection 16 is compressively deformed within the elastic deformation region, and the lower end surface 18 of the stopper 8 and the rack guide 7 are compressed. The position of the stopper 8 is adjusted so that there is a slight gap a between the stopper 8 and the flat part 15 of the stopper 8. Stoppa 8
After the position of the stopper 8 is adjusted, the stopper 8 is fixed with a tightening nut 11 to prevent the stopper 8 from loosening. The rack guide 7 is the cylindrical hole 6 of the housing.
In the assembled state, the annular elastic protrusion 20 of the rack guide is elastically deformed and comes into contact with the cylindrical hole 6 surface, and the protrusion upper surface 21 and the protrusion lower surface 2 of the annular elastic protrusion 20
Since the rack guides 2 and 2 have different angles with respect to the axial direction of the rack guide 7, the rack guide 7 can easily move toward the lower rack rod 4 within the cylindrical hole 6, but the annular elastic protrusion 20 acts as a wedge action toward the upper stopper 8. It is becoming difficult to work and move.

In the rack and pinion type steering device of this invention constructed as described above, the bending of the rack rod 4 due to heat treatment strain, etc., and the axis of the pinion shaft 2 and the rack rod 4 due to the machining precision of the teeth of the pinion 3 and rack 5. If the rack guide 7 is affected by minute displacements in the distance between the pinion shafts 2 and rack rods 4, or changes in the distance between the pinion shafts 2 and rack rods 4 due to sudden loads applied to the meshing tooth surfaces of the pinion 3 and the rack 5 during running, the rack guides 7 will stop. The rack guide 7 is pushed up and raised in the direction 8, and the flat portion 15 at the upper end of the rack guide 7 comes into contact with the lower end surface 18 of the stopper 8. However, when the rack guide 7 is raised, the elastic protrusion 16 of the rack guide that is in contact with the lower end surface 18 of the stopper 8 is further compressed and deformed by the lower end surface 18 of the stopper 8, and the rack guide 7 is
Since the movement in the upward direction within the rack guide 7 is restricted by the annular elastic protrusion 20 formed on the rack guide 7, it is possible to prevent the occurrence of a hitting sound when the flat portion 15 of the rack guide 7 comes into contact with the lower end surface 18 of the stopper 8. ,
In particular, since the rack guide 7 is made of an elastic material, there is no metal tapping sound that occurs when conventional metal materials are used. Furthermore, in the past, it was necessary to provide a certain clearance between the cylindrical hole 6 of the housing and the rack guide during processing or assembly, and if this clearance was large, it would be necessary to provide a certain clearance between the housing's cylindrical hole 6 and the rack guide. Then, the rack rod 4 became twisted with respect to the axis of the rack rod 4, so that the outer circumferential surface of the rack guide collided with the surface of the cylindrical hole 6 of the housing, producing a hammering sound. However, as mentioned above, by providing the annular elastic protrusion 20 on the rack guide 7, the generation of hammering noise is prevented, and the machining of the cylindrical hole 6 of the housing and the outer circumferential surface of the rack guide 7 does not require the high precision required in the past. This makes it possible to reduce processing costs and facilitate assembly and adjustment.

The annular elastic protrusions 16 formed at the upper end of the rack guide 7 are not limited to a plurality of conical projections; for example, tooth-shaped protrusions with a triangular cross section may be arranged radially toward the upper end of the rack guide 7, alternating with flat parts. You may also set it. In addition, a plurality of annular elastic protrusions 20 formed on the outer peripheral surface of the rack guide 7
The cross-sectional shape of the housing is not limited to a triangular shape, and for example, the portion that contacts the cylindrical hole 6 of the housing may have a circular arc or a small radiused portion.

As described above, the rack and pinion steering device of this invention includes a housing, a pinion shaft rotatably supported within the housing, a rack rod having a rack formed thereon that engages with a pinion of the pinion shaft, and a rack rod provided within the housing. A rack guide made of an elastic material is fitted into a cylindrical hole, a stopper is screwed onto a threaded portion at the end of the cylindrical hole, and a stopper is provided between the stopper and the rack guide to press the rack rod against the pinion via the rack guide. In a rack and pinion steering device equipped with a spring, the rack guide includes a plurality of annular elastic protrusions provided on the outer circumferential surface,
By forming an elastic protrusion protruding from the flat part provided on the end face on the stopper side, it is possible to prevent the occurrence of hitting noises while driving, and to prevent the operator from feeling uncomfortable due to hitting noises and vibrations. In addition, there were effects such as reduction in processing costs and ease of assembly and adjustment.

[Brief explanation of the drawing]

The drawings show an embodiment of the rack-and-pinion steering device of this invention, in which Fig. 1 is a longitudinal sectional view, Fig. 2 is an enlarged view of the main part of Fig. 1 with a partially cutaway section, and Fig. 3 2 is a plan view taken along line A-A in FIG. 2 in the direction of the arrow. 1...Housing, 2...Pinion shaft, 3...
Pinion, 4...Rack rod, 5...Rack, 6...
... Cylindrical hole, 7 ... Rack guide, 8 ... Stopper, 9 ... Spring, 10 ... Threaded part, 15 ... Plane part, 16 ... Elastic projection, 20 ... Annular elastic projection.

Claims (1)

[Scope of utility model registration request] a housing, a pinion shaft rotatably supported within the housing, a rack rod having a rack formed thereon that engages with a pinion of the pinion shaft;
a rack guide made of an elastic material fitted into a cylindrical hole provided in the housing; a stopper screwed into a threaded portion at the end of the cylindrical hole; and a rack guide provided between the stopper and the rack guide. and a spring for pressing the rack rod against the pinion through the rack guide, wherein the rack guide includes a plurality of annular elastic protrusions provided on the outer peripheral surface and capable of abutting against the cylindrical hole surface; A rack and pinion type steering device characterized by having an elastic protrusion that protrudes from a flat portion provided on an end surface on the stopper side and can come into contact with the lower end surface of the stopper.