JPS6128518Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a boot seal for a rack and pinion mechanism used in the steering of an automobile.

Conventionally, in this type of rack and pinion mechanism, for example, as shown in FIG. 1, a rack bar 3 is slidably inserted into a rack bar housing 1 fixed to the chassis side by a bearing bush 2. A link rod 5 is connected to the end of the rack bar 3 via a ball joint 4, and the rack bar 3 is slid by a pinion that rotates when the steering wheel is operated to change the steering angle of the front wheels. There is.

In such a rack and pinion mechanism, in order to prevent water, dust, etc. from entering the rack bar 3 and the ball joint 4 that protrude from the rack bar housing 1, the rack bar 3 and the ball joint 4 are surrounded. A boot seal 6 having a bellows structure that can be expanded and contracted in the axial direction is provided for sealing, and the air inside the boot seal 6 due to expansion and contraction of the boot seal 6 when the rack bar 3 slides is transferred to the opposite side. In order to improve the movement of the rack bar 3 by flushing with the boot seal provided in the same manner as the rack bar housing 1 and the boot seal provided in the same way, the bearing It is provided in the part of the rack bar housing 1 that is inside the bush 2.

However, in the case of the boot seal 6 as described above, for example, when the rack bar 3 is moved to the right side or when the link rod 5 is swung due to vibration, the boot seal located on the outer circumference of the rack bar housing 1 is damaged. The portion 6a of the seal 6 is crushed and obstructs the flow of fluid between the inside of the boot seal 6 and the intershaft gap 7 that communicates through the communication hole 8, resulting in poor movement of the rack bar 3. I had a problem with the steering wheel becoming heavier as I got older.

The present invention was developed by focusing on this conventional problem, and includes a plurality of seals that contact the rack bar housing on the inner peripheral surface of the boot seal that surrounds the outer periphery of the rack bar housing. By providing a protrusion to prevent the boot seal from being crushed,
The purpose is to solve the above problems.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 2 is a cross-sectional view showing one embodiment of the present invention attached to a rack and pinion mechanism.

First, to explain the structure, the rack and pinion mechanism includes a rack bar housing 1 fixed to the chassis side, and a rack bar 3 slidably fitted into the rack bar housing 1 by a bearing bush 2.
and a link rod 5 connected to the tip of the rack bar 3 via a ball joint 4, and the boot seal 10 of the present invention is constructed by connecting the protrusion of the rack bar 3 and the ball joint 4 of such a rack and pinion mechanism. One side is fixed to the link rod 5 by a clamp ring 11, and the other side is fixed to the rack bar housing 1 by a clamp 12.

This boot seal 10 has an elastic portion 10a formed in a bellows shape in the center, and the elastic portion 10a
A plurality of spherical protrusions 13 are provided in a houndstooth pattern on the inner circumferential surface of the surrounding portion 10b of the rack bar housing 1, which is also shown in FIG. As is clear, there is sufficient spacing between the respective spherical protrusions 13 when viewed from the axial direction, so even if the spherical protrusions 13 are provided, the fluid flow is not obstructed in any way.

Of course, the arrangement of the spherical protrusions 13 is not limited to the staggered arrangement in the illustrated embodiment, and when viewed from the axial direction as shown in FIG. Any arrangement may be used as long as they are located at equal intervals around the entire circumference.
Further, instead of the spherical protrusion 13, a cylindrical or trapezoidal protrusion may be used.

Next, the action will be explained.

The rack and pinion mechanism shown in FIG. 2 is equipped with a similar mechanism in which a boot seal is attached to the left side of the rack bar housing 1, and the inside of the boot seal 10 provided on both sides is provided with a communication hole 8. The shafts communicate with each other through an interaxial gap 7 of the rack bar housing 1.

Therefore, if the rack bar 3 is slid to the right by operating the steering wheel, the boot seal 10 will extend due to the protrusion of the rack bar 3, while the left boot seal (not shown) will contract. Even if fluid flows through the boot seal 10 and the internal volume of the boot seal 10 changes, the internal volume of the entire boot seal remains constant, so the movement of the rack bar 3 is not hindered in any way.

On the other hand, as the rack bar 3 is moved to the right as shown by the arrow, the elastic part of the boot seal 10 stretches, and the surrounding part 10b is also pulled and tries to collapse, but the inside of the surrounding part 10b Since a plurality of spherical protrusions 13 are provided to support the boot seal 10, the boot seal 10 is prevented from collapsing, and a sufficient clearance is ensured between the surrounding portion 10b and the rack bar housing 1. The flow of fluid from the other boot seal into the boot seal 10 is unimpeded, ensuring smooth movement of the rack bar 3.

Of course, even when the link rod 5 swings relative to the rack bar 3, the shape of the surrounding portion 10b is maintained by the spherical protrusion 13, and the flow of fluid is not obstructed.

As explained above, according to the present invention, the configuration is such that a plurality of protrusions that come into contact with the rack bar housing are provided on the inner peripheral surface of the boot seal surrounding the outer periphery of the rack bar housing. This prevents the boot seal from collapsing at the rack bar housing, which facilitates fluid flow between the boot seals on both sides and reliably reduces friction in the rack and pinion mechanism. This effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a partial sectional view of a rack and pinion mechanism using a conventional boot seal, Fig. 2 is a sectional view of a rack and pinion mechanism using a boot seal which is an embodiment of the present invention, and Fig. 3 is a partial sectional view of a rack and pinion mechanism using a boot seal according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of the boot seal taken along the AA cross section in the figure. 1... Rack bar housing, 2... Bearing bush, 3... Rack bar, 4... Ball joint, 5... Link rod, 6, 10... Boot seal, 7... Intershaft gap, 8... communication hole,
10a... Telescopic part, 10b... Surrounding part, 11...
Clamp ring, 12... Clamp, 13... Spherical protrusion.

Claims (1)

[Scope of Claim for Utility Model Registration] A rack bar housing is provided in which a rack bar connected to a link rod via a ball joint is supported by a bearing bush and slidably inserted therein, An axially expandable boot seal is provided to surround and seal the protruding portion and the ball joint portion, and a hole is provided from the inside of the boot seal to communicate with the interaxial gap between the rack bar housing and the rack bar. , in the boot seal of the rack and pinion mechanism provided inside the bearing bush mounting position of the rack bar housing, the rack bar housing A boot seal characterized by having a plurality of protrusions that come into contact with the boot seal.