JPH0594055U - Rack and pinion type power steering system boot - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent interference with the socket part of the ball joint when the boot covering the connecting part of the rack and tie rod of the rack and pinion type power steering device contracts. [Structure] A rack 4 slidably supported in a rack housing 2 and a tie rod 10 form a ball joint 8
Are connected via. The connecting portion is covered by a boot 14 which has one end fitted to the rack housing and the other end fitted to a tie rod. The fitting portions A and E at both ends of the boot are thick in thickness, and the intermediate portions B to D are thin. Further, the portions B to C closer to the housing in the middle portion are thinner than the portions C to D closer to the tie rod. [Effect] When the boot is contracted, the thin portion of the middle portion near the housing is folded first, so that the other portions do not meander.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a rack and pinion type power steering device, and more particularly to a boot for protecting a connecting portion between a rack and a tie rod.

[0002]

[Prior Art]

 Generally, in a rack and pinion type power steering system, tie rods are connected via ball joints to both ends of a rack that is fitted in a housing and supported in a sliding manner, and one end is surrounded by these tie rods. The outer periphery of the housing is covered with resin boots, the other ends of which are fitted to the outer periphery of the tie rod, respectively, to protect water and dust from entering.

In the conventional boot mounted around the connecting portion between the rack and the tie rod, both ends fitted to the outer periphery of the housing and the tie rod are thick, and the middle portion thereof is thick. It is thin. FIG. 5 is a diagram showing the wall thickness of a conventional boot. The left end L is a fitting part to a housing, the right end R is a fitting part to a tie rod, and F is a rack and a tie rod connected by a ball joint. It is the intersection point.

[0004]

[Problems to be solved by the device]

 In the rack and pinion type power steering system, since the tie rod and the rack have a crossing angle at the connecting portion, the conventional boot described above has the above-mentioned structure when contracted when the internal pressure of the boot rises due to high temperature. The thin wall part meanders, and the inner surface on the valley side interferes with the socket part into which the ball joint of the tie rod is inserted, which causes abnormal noise and reduces durability. ..

The present invention has been made to eliminate the above problems, and provides a boot for a rack and pinion type power steering device in which the inner surface of the boot does not interfere with the socket portion of the tie rod.

[0006]

[Means for Solving the Problems]

 The boot according to the present invention is a rack and rack of a rack and pinion type power steering device including a rack slidably supported in a housing and a tie rod connected to an end of the rack via a ball joint. It protects the connection part with the tie rod, and one end is fitted to the outer circumference of the housing and the other end is fitted to the outer circumference of the tie rod, and the wall thickness of the parts fitted to these housing and tie rod is It is thicker than the middle part, and the thickness of the part of the middle part near the housing is thinner than that of the part near the tie rod.

[0007]

[Action]

 When the boot is constructed as described above, the thin part in the middle part is folded first when it contracts, so it is difficult for the other parts to meander.Especially when the temperature around the boot is high, the socket part of the ball joint Can be prevented from interfering with.

[0008]

【Example】

 The present invention will be described below with reference to embodiments shown in the drawings. FIG. 1 is a vertical cross-sectional view of a rack and pinion type power steering apparatus having boots according to an embodiment of the present invention. A rack 4 slidably supported in a rack housing 2 is provided in a gear housing 6. The rack 4 is meshed with a pinion (not shown) which is rotatably supported, and the rack 4 reciprocates by the rotation of the pinion by the operation of the steering wheel. A tie rod 10 is connected to an end of the rack 4 via a ball joint 8. The ball joint 8 includes a socket portion 12 screwed and fixed to the end surface of the rack 4 and a ball portion 10 a provided at an end portion of the tie rod 10 and rotatably fitted in the socket portion 12. Is becoming

The periphery of the connecting portion between the rack 4 and the tie rod 10 is covered with a boot 14 made of a material such as resin, and is protected so that muddy water and dust do not enter inside. The boot 14 has one end 14a (on the left side in the drawing) fitted to the outer circumference of the rack housing 2, and the other end 14b fitted to the outer circumference of the tie rod 10. The boot 14 has a wall thickness as shown in FIG. That is, the portion A (14a) fitted to the rack housing 2 and the portion E (14b) fitted to the tie rod 10 are thick, and the portion A (14a) directed from these positions toward the intermediate portion is thick. The thickness of B to E and the thickness of E to D are gradually reduced, and the thickness of the intermediate portions B to D is smaller than that of both end portions A and E. Further, of the intermediate portions B to D, the portions B to C near the rack housing 2 are thinner than the portions C to D near the tie rod 10. The solid line in the lower part of FIG. 2 is a diagram showing the wall thickness of the boot 14, and the broken lines B to C show the wall thickness of the conventional boot for comparison. The thickness of the boot is different in the peaks and valleys of the boot, and changes in the slope connecting them, but it means the average thickness including these.

In the conventional rack and pinion type power steering system including the boot 24, as shown in FIG. 4, when the rack 4 and the tie rod 10 move leftward and the boot 24 contracts, the middle of the boot 24 is lost. There is a possibility that the portion will be deformed as a whole and meander to interfere with the socket portion 12 of the ball joint 8, but in this embodiment, since the thickness of the boots 14 was changed as described above, When the rack 4 and the tie rod 10 move to the left in FIG. 1 and the boot 14 contracts, the thin portions B to C of the boot 14 that are thin and have low rigidity are folded first. The meandering is reduced, and the interference with the socket portion 12 of the ball joint 8 connecting the tie rods 10 can be prevented.

[0011]

[Effect of the device]

 As described above, according to the present invention, a thin and low-rigidity portion is provided near the portion of the boot fitted to the housing, that is, at the portion far from the intersection of the rack and the tie rod. It is designed to be folded first when it is contracted, and the highly rigid part near the intersection of the rack and the tie rod is less likely to meander, preventing the inner surface of the boot from interfering with the socket part of the ball joint and improving the durability of the boot. It is possible to improve the performance and reduce the interference noise, especially in an environment where the temperature around the boot is high.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a main part of a rack and pinion type power steering apparatus including boots according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of the boot and a diagram showing the wall thickness of each part thereof.

FIG. 3 is an explanatory diagram showing a state of boots when the rack and pinion power steering apparatus is in operation.

FIG. 4 is an explanatory view showing a state of boots when a conventional rack and pinion type power steering apparatus is in operation.

FIG. 5 is a diagram showing the wall thickness of a conventional boot.

[Explanation of symbols]

 2 housing 4 rack 8 ball joint 10 tie rod 14 boot A part fitted to the housing of the boot B to C part of the middle part of the boot close to the housing c to D part of the middle part of the boot close to the tie rod E to the tie rod of the boot Fitted part

Claims (1)

[Scope of utility model registration request] 1. A rack slidably supported in a housing, a tie rod connected to the end of the rack via a ball joint, and one end on the outer periphery of the housing.
In a rack and pinion type power steering apparatus, the other end of which is fitted to the outer periphery of a tie rod, and which includes boots that cover the periphery of the connecting portion between the rack and the tie rod, the portion that is fitted to the housing and the tie rod. The rack and pinion type power rudder is characterized in that the thickness of the boot is thicker than the middle part thereof, and the thickness of the middle part near the housing is thinner than the wall thickness near the tie rod. Boot of the taker.