JPS63180573A - Steering boot - Google Patents

Abstract

PURPOSE:To prevent a depression of a steering boot owing to a negative pressure, by making the thickness near a ball joint larger. CONSTITUTION:A steering boot 11 consists of a synthetic rubber, and is composed in a bellows-form cylinder with a flexible large diameter part 11a and a small diameter part 11b. The steering boot 11 covers a rack shaft 12, a tie rod 15a, and a ball joint 16 inside thereof. In the steering boot 11 near the ball joint 16, the thickness t1 at the bending portion 11e is formed larger than the thickness t0 other than the bending portion.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a steering boot, and more particularly, to a steering boot that covers a part of a transmission mechanism that transmits rotation of a steering wheel of a vehicle to left and right tie rods.

(Prior Art) As a conventional steering boot, there is one shown in FIG. 3, for example. In FIG. 3, 1 is a steering boot, and an inner end 1a (left end in the figure) of the steering boot 1 is fixed to an end 3a of a rack housing 3 that accommodates a rack shaft 2 of a rack and pinion gear.

An outer end 1b (right end in the figure) of the steering boot 1 is fixed to the tie rod 5 by covering a portion 5a of the tie rod 5. The tie rod 5 and the rack shaft 2 are connected by a ball joint 6, and the steering boot 1 covers the rack shaft 22, a portion 5a of the tie loft 5, and the ball joint 6. As the steering wheel rotates when the vehicle is running, the rack shaft 2 of the rack and pinion gear moves left and right in the figure, and the tie rod 5 moves as shown in the figure.
As shown in the dashed line in Figure 3, the ball joint 6
Make repeated rotational movements around the center. Therefore, the steering boot 1 repeatedly expands and contracts in its axial direction, and is repeatedly bent and deformed in the vicinity of the ball joint 6 as the tie rod 5 rotates.

(Problem to be Solved by the Invention) However, the inner end 1a and outer end 1b of the steering boot 1 are fixed to the end 3a of the rack housing 3 and the tie rod 5, respectively, and the rank shaft 2
As a result of the movement of the steering boot 1, a large negative pressure is generated inside the steering boot 1, and the steering boot 1 is repeatedly bent and deformed near the ball joint 6.
There is a problem in that a recess 1d as shown by the dotted line in FIG. 3 occurs in C. Further, there is a problem in that the repeated occurrence of the dent 1d and the repeated bending deformation of the steering boot 1 cause the bent portion IC to become fatigued and eventually cause cracks 1e.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a highly durable steering boot that does not cause dents or cracks even when the steering boot is repeatedly expanded/contracted and repeatedly bent and deformed as the steering wheel rotates and the rack shaft moves. shall be.

(Means for Solving the Problems) A steering boot according to the present invention has an inner end fixed to a rack housing, an outer end fixed to a tie rod, and connects a rack shaft and a part of the tie rod, and the rack shaft and the tie rod. In the bellows-shaped steering boot that covers each ball joint,
The steering boot is characterized by an increased wall thickness near the ball joint.

(Function) Since the steering boot of the present invention has a large wall thickness near the ball joint, the strength and rigidity of the steering boot near the ball joint increases. Therefore, even if negative pressure is applied to the steering boot, no dents or cracks will occur.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1.2 is a diagram showing an embodiment of the steering boot according to the present invention.

First, the configuration will be explained. In FIG. 1, 11 is a steering boot, and the steering boot 11 is made of synthetic rubber, and has a large diameter part 11a and a small diameter part 11 which can be expanded and contracted.
It is a bellows-shaped cylindrical body having b. An inner end (left end in the drawing) 11C of the steering boot 11 is fixed to a cylindrical end 13a of a rack housing 13 that accommodates a rack shaft 12 of a rack and pinion gear (not shown). An outer end (right end in the figure) 11d of the steering boot 11 covers a portion 15a of the tie rod 15 and is fixed to the tie rod 15. The tie loft 15 and the rack shaft 12 are rotatably connected by a ball joint 16. The steering boot 11 includes a rack shaft 12, a portion 15a of the tie rod 15, and a ball joint 16.
is covered. Near the ball joint 16 of the steering boot 11, that is, the steering boot 11
When the large diameter portion 11a and the small diameter portion 11b of the steering boot 11 are connected and the tie rod 15 rotates, the thickness t1 of the three peaks of the bent portion lie of the steering boot 11 that bends and deforms is the same as that of the bent portion Lie of the steering boot 11. The thickness is larger than the other wall thickness t0, and the strength increases. The rigidity increases as well.

Next, the effect will be explained.

When the vehicle is running, the rotation of the steering wheel causes the rank shaft 12 of the rack and pinion gear to move left and right in the figure, and the tie rod 15 rotates about the ball joint 16. Negative pressure is generated inside the steering boot 11 due to the movement of the rack shaft 12, and
The steering boot 1 is rotated by the rotational movement of the tie rod 15.
1 is repeatedly bent and deformed at a bent portion lie near the ball joint 16.

The wall thickness t of the bent portion lie of the steering boot 11.

is larger than the wall thickness t0 of the steering boot 11 other than the bent portion, and the strength and rigidity of the bent portion lie of the steering boot 11 is increased, so that the bent portion lie of the steering boot 11 is not dented by negative pressure. Even if the bent portion Lie of the steering boot 11 is subjected to repeated bending deformation, the bent portion 11e will not get fatigued and cracks will not occur. Also, there is no possibility of the rack shaft becoming bent due to being caught in the rack shaft. Therefore, the durability of the steering boot 11 is significantly improved.

(Effects) As explained above, according to the present invention, it is possible to prevent the steering boot from forming dents due to negative pressure due to rotation of the steering wheel and movement of the rack shaft, and also prevent dents or cracks from forming due to bending deformation. The durability of the steering boot 11 can be greatly improved.

[Brief explanation of the drawing]

1.2 are diagrams showing one embodiment of the steering boot according to the present invention, FIG. 1 is a longitudinal cross-sectional view of the steering boot in use, and FIG. 2 is a cross-sectional view of its essential parts. FIG. 3 is a longitudinal cross-sectional view showing a conventional steering boot in use. 11... Steering boots, 11a...
...Large diameter part, 1.1b...Small diameter part, 11C...Inner end, lid...Outer end, Lle...Bending part, 12. ... Rack shaft, 13 ... Rank housing, 13a ... End, 15 ... Tie rod, 15a ... Part, 16 ... ...Ball joint.

Claims (1)

[Claims] In a bellows-shaped steering boot whose inner end is fixed to the rack housing and whose outer end is fixed to the tie rod, and which covers the rack shaft, part of the tie rod, and the ball joint that connects the rack shaft and the tie rod, A steering boot characterized by increased thickness of the steering boot.