JPH1182737A - Boot seal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To follow the movement of an expansive and contractive flexible body with a margin and avoid interference to an object installed in the peripheral part of the outer circumference at the time of expansion and contraction by setting the extent of expansion and contraction in a region surrounding an expanded part to be relatively smaller than the extent of expansion and contraction in other regions. SOLUTION: In a boot seal 20, the extent of expansion and contraction and the degree of flexibility are increased more as much as possible in regions B besides a region A than those in the region A surrounding a ball joint 14. Consequently, the extent of expansion and contraction and the degree of flexibility of the boot seal 20 as a whole are increased. Sufficient clearance is reliably kept between the inner circumferential part of a bellows part 21 of the boot seal 20 and the ball joint 14 of a rack end 10 and also between the outer circumferential part and a side wall face 30 in the automobile body side an engine room to avoid interference. As a result, the conformability of the boot seal 20 to the expansion and contraction and flexible movement of the rack end 10 can be heightened and interference of the rack end 10 in other objects 14, 30 can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bellows-shaped boot seal. The boot seal is used to protect a rack end in a rack and pinion type steering device of, for example, an automobile. The above-mentioned rack end refers to a portion where a tie rod bar is mounted via a ball joint to a free end of a rack bar which is immersed in and protrudes from a rack housing, as is well known.

[0002]

2. Description of the Related Art In a boot seal used for protecting a rack end in the above-described rack and pinion type steering apparatus, a corrugated shape of a bellows portion has a constant size in a longitudinal direction. In other words, both the diameter of each peak and the diameter of each valley of the bellows portion are:
It is set substantially constant throughout the longitudinal direction.

[0003] At one end in the longitudinal direction of the boot seal,
A small-diameter mounting part that is fitted and fixed to the tie rod bar
At the other end in the longitudinal direction, large-diameter mounting portions that are externally fitted and fixed to the rack housing are provided, and the boot seal itself is positioned relative to the rack end and is fixedly mounted. Along with such an attached state, the boot seal expands and contracts when the rack bar enters and protrudes from the rack housing, and moves so as to bend in the longitudinal direction along with the swing of the tie rod bar with respect to the rack bar. I do.

[0004]

Generally, in the above-described boot seal, it is necessary to design the boot seal so that it can follow the expansion and contraction stroke of the rack end of the rack and pinion type steering apparatus with a margin.

By the way, if the wavy amplitude (height between peaks and valleys) of the bellows portion of the boot seal is designed to be large, the amount of expansion and contraction of the boot seal can be increased.

However, if the amount of expansion and contraction of the bootseal is designed to be larger than necessary, the amount of flexibility naturally increases, so that the inner and outer peripheral portions of the bellows portion of the bootseal are rack-pinion. The large-diameter ball joint at the rack end of the type steering apparatus and the side wall surface of the vehicle body constituting the installation space for the rack end are liable to interfere with each other, and are easily rubbed and damaged.

[0007] In particular, in recent years in which the space between the rack end of the rack and pinion type steering device and the side wall surface of the vehicle body is designed to be narrow with the recent miniaturization of each part of the vehicle, especially the side wall surface of the vehicle body It becomes difficult to avoid the interference of the boot seal.

For this reason, in designing a boot seal, it is necessary to ensure the ability to follow the movement of the object to be protected while avoiding interference between the boot seal and other objects, but these conditions are satisfied. Since the designs are contradictory, it is difficult to make these conditions compatible, and at present it is necessary to sacrifice either one. For example, if the followability is sacrificed, the fatigue life tends to be shortened due to a tensile load or a compressive load applied to the bellows portion, while if sacrificed to avoid interference, as described above, the tire tends to be damaged.

Accordingly, the present invention is directed to a boot seal, which secures an amount of expansion and contraction capable of following the movement of an expandable flexible object to be protected with a margin while protecting an expandable elastic object and an object arranged close to the outer periphery thereof. It is an object of the present invention to avoid interference during expansion and contraction and flexibility.

[0010]

A boot seal according to the present invention is a bellows-shaped boot which is wrapped around a long stretchable flexible object having a large-diameter bulge partway in the longitudinal direction. In the seal, the amount of expansion and contraction in other regions is set to be relatively larger than the amount of expansion and contraction in the region surrounding the bulging portion.

A boot seal according to a second aspect of the present invention is a bellows-shaped boot seal that is wrapped around a long and stretchable flexible object having a large-diameter bulge partway in the longitudinal direction,
A first end which is externally fitted and fixed at one end in the longitudinal direction near the bulging portion;
A second mounting portion is provided at the other end in the longitudinal direction of the mounting portion, the second mounting portion being externally fitted and fixed to a portion distant from the bulging portion, and from the first mounting portion side to the second mounting portion side. The amount of expansion and contraction is set to increase gradually.

A boot seal according to a third aspect of the present invention is a bellows-shaped boot seal which is mounted around the rack end of the rack and pinion type steering device, and which expands and contracts in a region surrounding the ball joint of the rack end. The amount of expansion and contraction in other areas is set to be relatively large.

A boot seal according to a fourth aspect of the present invention is a bellows-shaped boot seal that is wrapped around the rack end of a rack and pinion type steering device, and has one longitudinal end near a ball joint of the rack end. A small-diameter mounting portion that is externally fitted and fixed is provided, and a large-diameter mounting portion that is externally fixed to the rack housing at the rack end is provided at the other end in the longitudinal direction, and the small-diameter mounting portion side to the large-diameter mounting portion side. It is set so that the amount of expansion and contraction gradually increases toward.

A boot seal according to a fifth aspect of the present invention is the boot seal according to any one of the first to fourth aspects, wherein the amount of expansion and contraction is set by changing a height dimension between a peak and a valley of the bellows portion. Is what is done.

According to a sixth aspect of the present invention, in the boot seal according to the fifth aspect, the outer diameter of each of the peaks in substantially the entire region in the longitudinal direction is set to be substantially constant.

In the present invention, in short, the amount of expansion and contraction of the boot seal is not substantially constant throughout the longitudinal direction but is partially changed. In addition, regarding the region where the amount of expansion and contraction is increased, considering that the amount of flexibility is also increased, by setting the region where the bulging portion of the expandable and contractible object does not exist, it is difficult to interfere with the bulging portion. I have. Also, in a region where the amount of expansion and contraction is increased, the valley portion protrudes toward the inner diameter side instead of the ridge portion protruding toward the inner diameter side, so that an object disposed close to the outer periphery of a long stretchable flexible object when flexible. Interference.

From the above, the boot seal of the present invention can follow the movement of the telescopic flexible object with a margin and can avoid interference with other objects. The flexible object can be stably protected for a long period of time.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS.

FIGS. 1 to 3 relate to an embodiment of the present invention. FIG. 1 is a longitudinal sectional view showing a use state of a boot seal, FIG. 2 is a longitudinal sectional view of the boot seal alone of FIG.
FIG. 2 is an explanatory view showing the boot seal of FIG. 1, the conventional boot seal, and a compressed form.

In the figure, reference numeral 10 denotes a rack end of the rack and pinion type steering device, and reference numeral 20 denotes a boot seal for protecting the rack end 10.

The rack end 10 is a rack housing 1
1, a rack bar 12 immersed in and projected from the rack housing 11, and a tie rod bar 13 swingably connected to the rack bar 12 via a ball joint 14.
And The rack end 10 corresponds to a telescopic flexible object described in claims, and the ball joint 14 corresponds to a bulging portion described in claims.

The boot seal 20 is integrally formed of an elastic material such as a synthetic rubber (for example, chloroprene rubber) or a synthetic resin (for example, a polyolefin-based elastomer). A cylindrical small-diameter mounting portion 22 provided at one longitudinal end of the bellows portion 21 and externally fixed to the vicinity of the ball joint 14 in the tie rod bar 13 of the rack end 10; And a cylindrical large-diameter mounting portion 23 which is provided at the other end in the direction and is externally fitted and fixed to the rack housing 3. A clamp ring (not shown) is attached to the outer periphery of the small-diameter mounting portion 22 and the large-diameter mounting portion 23, so that the mounting position is prevented from being shifted by tightening the clamp ring.

Next, the characteristic configuration of the boot seal 20 of the present embodiment will be described. That is, in the bellows portion 21 of the boot seal 20, the amount of expansion and contraction in the other region (B in FIG. 2) is set to be relatively larger than the amount of expansion and contraction in the region surrounding the ball joint 14 (A in FIG. 2). ing. In this embodiment, the boot seal 20 is set so that the amount of expansion and contraction gradually increases from the small-diameter mounting portion 22 side to the large-diameter mounting portion 23 side.

Specifically, as shown in FIG. 2, the wavy shape of the bellows portion 21, that is, the height dimension (radial size) between the peak portion 24 and the valley portion 25 of the bellows portion 21, It gradually increases from the small-diameter mounting portion 22 side to the large-diameter mounting portion 23 side. That is, the relationship h ₁ <h ₂ <h ₃ is set. Accordingly, the pitch between the mountains is w ₁ <w ₂ <w ₃
And gradually increasing. The diameters of the peaks 24 in substantially the entire longitudinal direction of the bellows 21 of the boot seal 20 are set to be substantially the same.

Because of this, the boot seal 20
Is an envelope X connecting the peaks 24 of the bellows 21 with the central axis O.
And the valley 25 of the bellows 21
Are connected from the small-diameter mounting portion 22 side to the large-diameter mounting portion 23.
It has a tapered shape whose diameter gradually decreases toward the side. The area C of the bellows portion 21 on the side of the small-diameter mounting portion 22 is set so that both the inner and outer diameters are reduced as approaching the small-diameter mounting portion 22. This is a portion connecting the bellows portion 21 and can have an arbitrary shape.

As described above, in short, by increasing the amount of expansion and contraction and the amount of flexibility in the other area B as much as possible in the area A surrounding the ball joint 14 in the boot seal 20, The overall amount of expansion and contraction and the amount of flexibility are expanded as compared with the conventional example. Then, the bellows portion 21 of the boot seal 20
Ball joint 14 of the inner peripheral portion of the rack end 10
, And between the outer peripheral portion and the vehicle body side wall surface 30 in the engine room. Thereby, while the followability of the boot seal 20 with respect to the expansion / contraction and flexible movement of the rack end 10 is improved, other objects (
0) can be avoided.

By the way, in the boot seal 20, as shown in FIG. 3 (a), the valleys 25 are displaced in the radial direction and do not overlap in the longitudinal direction during compression, so that it is easy to compress, and furthermore, Since the amount of elastic deformation of the valley 25 in the state is suppressed, the durability is improved. By the way, in the conventional boot seal in which the envelope connecting the peaks and the envelope connecting the valleys are both parallel to the axis, as shown in FIG. In addition, since they overlap in the longitudinal direction, they are hardly compressed, and the elastic deformation of the peaks 24 and the valleys 25 in the compressed state tends to increase, so that the durability tends to decrease. This also makes it possible to achieve a smooth expansion and contraction operation of the boot seal 20, thereby improving the followability of the rack end 10 with the expansion and contraction operation and contributing to an improvement in the durability of the boot seal 20. I have.

It should be noted that the present invention is not limited to only the above-described embodiment, and the following modifications are conceivable.

(1) Boot seal 2 in the above embodiment
At 0, if the number of peaks / valleys per unit length in the axial direction in the region A is increased, the amount of expansion / contraction can be further increased.

(2) In the above embodiment, the height of the peaks and valleys of the bellows portion 21 is gradually increased in one of the longitudinal directions. However, the other region than the region A corresponding to the position of the ball joint 14 is used. Since it is sufficient to make the height dimension of B relatively large, the height dimension is changed between the area A and the area B, and the height dimension in the area A and the height dimension in the area B are made constant. You may make it. In addition, instead of dividing the bellows portion 21 into two regions A and B, the height may be changed stepwise as two or more. Further, in the above embodiment, the pitch between the peaks of the bellows 21 is gradually increased.
All may be constant.

[0031]

According to the first aspect of the present invention, a boot seal,
Since it is possible to increase the amount of expansion and contraction of the entire boot seal while securing a sufficient clearance between the bulging portion of the telescopic flexible object and members arranged outside the boot seal, the boot seal can be replaced The telescopic operation can be performed with a margin without being hindered. Therefore, the tensile load and the compressive load applied to the bellows portion can be reduced, and the bellows portion can be prevented from rubbing against other objects to be damaged. Be able to contribute.

According to the second aspect of the present invention, in addition to the effect of the first aspect, by setting the amount of expansion and contraction of the boot seal in the longitudinal direction to be continuously changed, the entire expansion and contraction operation can be smoothly performed. Therefore, a load such as a tensile load or a compressive load that acts on the entire boot seal during the expansion and contraction operation can be almost uniformly applied, and local damage can be prevented for a long period of time.

According to the third aspect of the present invention, the telescopic flexible object is limited to the rack end of the rack and pinion type steering device in the first aspect, and the same effect as in the first aspect is obtained.

According to the fourth aspect of the present invention, the telescopic flexible object is limited to the rack end of the rack and pinion type steering device in the second aspect, and the same effect as in the second aspect is obtained.

According to the fifth aspect of the present invention, in addition to the effects of the first to fourth aspects, the amount of expansion and contraction is partially varied by varying the waving amplitude of the bellows portion. Since it is difficult to overlap in the longitudinal direction, smooth movement such as easy compression becomes possible.

According to the sixth aspect of the present invention, a part of the bellows portion protrudes not on the outer peripheral portion but on the inner peripheral portion, so that the bulging portion of the telescopic flexible object to be protected or the rack end of the rack and pinion type steering device is provided. In addition, it is possible to reliably avoid the interference with the ball joint, and also with the telescopic flexible object or the object arranged on the outer periphery of the rack end of the rack and pinion type steering device.

As described above, in the boot seal of the present invention,
A highly reliable boot seal capable of stably protecting a telescopic flexible object or a rack end of a rack and pinion type steering device for a long period of time can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a use state of a boot seal according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the boot seal alone shown in FIG. 1;

FIG. 3 is an explanatory view showing the boot seal of FIG. 1, a conventional boot seal, and a compressed form;

[Explanation of symbols]

Reference Signs List 10 Rack end of rack and pinion type steering device 11 Rack housing 12 Rack bar 13 Tie rod bar 14 Ball joint 20 Boot seal 21 Bellows part 22 Small diameter mounting part 23 Large diameter mounting part 24 Bellows peak 25 Bellows valley A Bellows A region surrounding the ball joint in the part B A tapered region in the bellows part 30 Body side wall surface

Claims (6)

[Claims] 1. A bellows-shaped boot seal that is enclosed and mounted on a long and stretchable flexible object having a large-diameter bulge partway in the longitudinal direction, and expands and contracts in a region surrounding the bulge part. A boot seal characterized in that the amount of expansion and contraction in other areas is set to be relatively larger than the amount. 2. A bellows-shaped boot seal which is wrapped around a long and stretchable flexible object having a large-diameter bulge partway in the longitudinal direction, wherein one end in the longitudinal direction is close to the bulge part. The first to be fitted externally
A second mounting portion is provided at the other end in the longitudinal direction of the mounting portion, the second mounting portion being externally fitted and fixed to a portion remote from the bulging portion, and from the first mounting portion side to the second mounting portion side. A boot seal characterized in that the amount of expansion and contraction is set to increase gradually. 3. A bellows-shaped boot seal enclosed and mounted on a rack end of a rack and pinion type steering device, wherein the expansion and contraction in other regions is larger than the expansion and contraction amount in a region surrounding the ball joint of the rack end. A boot seal characterized in that the amount is set relatively large. 4. A bellows-shaped boot seal enclosed and mounted on a rack end of a rack-and-pinion type steering device, wherein the small-diameter mounting portion is externally fixed to one end in a longitudinal direction near a ball joint of the rack end. However, at the other end in the longitudinal direction, there is provided a large-diameter mounting portion which is externally fixed to the rack housing of the rack end, so that the amount of expansion and contraction gradually increases from the small-diameter mounting portion side to the large-diameter mounting portion side. A boot seal characterized by being set. 5. The boot seal according to claim 1, wherein the amount of expansion and contraction is set by changing a height dimension of a peak and a valley of the bellows portion. And boots seal. 6. The boot seal according to claim 5, wherein the outer diameter of each ridge in substantially the entire region in the longitudinal direction is set to be substantially constant.