JP2005003048A - Boot for universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boot having improved durability and improved sealing performance at a separate portion of a separate type, to be expected. <P>SOLUTION: The boot for a universal joint comprises a bellows portion 15 formed of a rubber elastic material between a small diameter ring portion 11 and a large diameter ring portion 13, the separate portion D1 (D2) formed in a linear shape ranging from the small diameter ring portion 11 to the large diameter ring portion 15, the separate portion D1 (D2) being a thick portion, and a seal fastener F arranged thereon. Along a bus line ranging from the small diameter ring portion 11 to the large diameter ring porion 13 of the bellows portion 15, at least one streak of stress relief groove 17 is formed in the inner face and/or the outer face. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
【Technical field】
The present invention relates to a rubber joint elastic universal joint boot (hereinafter simply referred to as “boot”) used in universal joint parts of automobiles, machine tools, construction machines, and various industrial machines.
[0002]
More particularly, the present invention relates to an invention suitable for a boot which is divided in the vertical direction so that maintenance is easy and a fastener is arranged in the divided portion.
[0003]
Here, the description will be made mainly by taking the division type as an example, but the present invention is not limited to these, and the present invention can also be applied to a non-division (endless) type.
[0004]
[Background]
Conventionally, as a split type boot, a universal shaft joint boot having the following configuration has been proposed by the same applicant as the applicant of the present application (refer to the claims of Patent Document 1).
[0005]
“It is formed of a rubber-like elastic body, and a bellows portion is formed between the small-diameter ring portion and the large-diameter ring portion, and a linearly divided portion is formed from the small-diameter ring portion to the large-diameter ring portion. A meat fastener and a seal fastener are arranged.
The seal fastener is formed along one end edge of the divided portion, and has a belt-like occlusal ridge portion provided with a bulging engagement portion at the tip, and a rubber-like elasticity along the edge of the other divided portion. A universal joint boot having a structure formed of a body and comprising a band-shaped occluded portion provided with an occlusal groove that engages with the occlusal ridge. "
On the other hand, in the boot for a universal shaft joint having the above-described configuration, further improvement in durability and improvement in the sealing performance of the divided portion have been required.
[0006]
Although not affecting the inventiveness of the present invention, Patent Documents 2 and 3 and the like exist as split-type universal shaft joint boots. And this invention is applicable also to the division | segmentation type boot in patent document 2 * 3.
[0007]
[Patent Document 1]
Japanese Patent No. 2714635 [Patent Document 2]
JP-A-8-261432 [Patent Document 3]
Japanese Patent Laid-Open No. 9-119522
DISCLOSURE OF THE INVENTION
[0009]
[Problems to be solved by the invention]
In view of the above, the present invention has an object (problem) to provide a boot that can be expected to improve durability and further improve the sealing performance of a split part in a split type. It is.
[0010]
[Means for Solving the Problems]
It is formed of a rubber-like elastic body, and the space between the small diameter ring part and the large diameter ring part is the bellows part,
In a universal joint boot in which a linear divided portion is formed from a small diameter ring portion to a large diameter ring portion, the divided portion is a thick wall portion and a seal fastener is arranged,
At least one stress relief groove is provided on the inner surface and / or the outer surface along the generatrix from the small-diameter ring portion to the large-diameter ring portion of the bellows portion.
[0011]
The presence of stress relief grooves absorbs and relieves compression and tension loads that occur during bending. For this reason, further improvement in durability can be expected.
[0012]
Further, when the stress relief groove is formed along the outer side of the opposite end edge on one side of the thick portion, in addition to the improvement in the durability, the effect of making it difficult to generate internal grease leakage during the bending motion Play.
[0013]
Further, when the stress relief groove is formed on one or both of the outer surface and the inner surface along both sides or one side of the thick portion, the stress relaxation of the thick portion can be more effectively performed, and the divided portion Improvement in sealing performance can be expected.
[0014]
And it is desirable that the division part bulges inward to be a thick part, so that the contact pressure between the crests of the bellows part in the division part can be reduced.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the configuration.
In addition, about the same part as a prior art example, the same figure code | symbol is attached | subjected and all or one part of those description is abbreviate | omitted.
[0016]
The present embodiment is applied to the split type boot described in Patent Document 1 described above. As shown in FIGS. 1 to 3, it is formed of a rubber-like elastic body, and a space between the small diameter ring portion 11 and the large diameter ring portion 13 is a bellows portion 15, and linearly extends from the small diameter ring portion 11 to the large diameter ring portion 13. Divided portions D1 and D2 are formed, the divided portions D1 and D2 are thick portions, and a seal fastener F is disposed.
Here, the rubber-like elastic body includes not only natural rubber and synthetic rubber but also a thermoplastic elastomer having rubber-like elasticity.
[0017]
This boot (usually grease is enclosed in the boot) is molded in an expanded state by injection molding using a rubber material such as chloroprene rubber or acrylic rubber having grease resistance.
[0018]
And the boot of this embodiment is formed by the thick portions of the divided portions D1 and D2 bulging inward. For this reason, when the bellows part 15 bends along with the solid angle movement of the joint shaft of the universal shaft joint, the contact pressure between the peak parts of the bellows part 15 in the divided parts D1 and D2 can be reduced. That is, it contributes to the improvement of the durability of the boot.
[0019]
Here, the thickness d1 of the thick portion in the divided portions D1 and D2 is 4 to 5 mm when the thickness d2 of the general portion G is 2 mm. The width of the thick portion is 10 to 11 mm in total of D1 and D2 (see FIG. 3).
[0020]
And the seal | sticker fastener structure is set as the structure as shown in patent document 1, ie, the structure shown in FIGS.
[0021]
The seal fastener F is formed along the edge of one division part D1, and is formed along the edge of the band-shaped occlusal protrusion 5 having the bulging engagement part 3 at the tip and the other division part D2. The structure is composed of a band-like portion 9 to be bite provided with a keyhole-like occlusal groove 7.
[0022]
Here, the thickness of the general portion of the occlusal ridge portion 5 is configured to be smaller than the gap between the opening end portions of the occlusal groove 7. The occlusal ridge 5 is made of a linear spring material, and a sandwiched insert 6 having a corrugated plane as shown in FIG. 4 is embedded, and the occlusal ridge 5 is given rigidity in the occlusal direction. The sandwiched insert 6 has a width that can be embedded from the general portion to the bulging engagement portion 3 of the occlusal protruding ridge portion 5. The corrugated pitch of the sandwiched insert 6 is 2 to 5 mm when the wire diameter is 0.3 mm and the width is 6 mm.
[0023]
As shown in FIG. 5, a sandwiching insert 8, which is made of a linear spring material and has substantially no corners, is embedded in the outer peripheral portion of the occlusal groove 7. A spring clamping force is applied between the open ends. Further, these insert materials are not limited to metal, and may be hard plastic as long as a predetermined spring force can be applied. Up to this point, the configuration is the same as the conventional configuration.
[0024]
In the present embodiment, in the vicinity of the seal fastener F, one stress relief groove 17A is formed on the outer side along the outer side of the opposite end edge of one of the thick portions (D1 side in the example), and the inner side The two stress relief grooves 17B are formed along the inner surfaces of the divided portions F, that is, the thick portions D1 and D2.
[0025]
With this configuration, it has been found that grease leakage during bending motion is less likely to occur than before. The reason is estimated as follows.
[0026]
That is, as shown in FIGS. 6 to 7, when the boot 1 is bent, its cross section becomes an elliptical shape, and receives a compression action on the outer surface side in the major axis direction of the ellipse and a tensile action on the outer surface side in the minor axis direction.
[0027]
In the case of the conventional example in which the stress relief grooves 17A and 17B are not formed in the divided portion, as shown in FIG. 8, since the stress relief groove 17 does not exist, when the boot outer surface is compressed, the outer surface is expanded on the inner surface side as a fulcrum. Directional force is generated, and a wedge-shaped opening 19 is generated on the inner surface side of the boot. That is, grease enters the wedge-shaped opening 19 and conversely, when the boot is pulled outward, the wedge-shaped opening 19 is closed and conversely, a wedge-shaped opening is formed on the outer surface side, and grease leakage may occur due to the pump action. is there.
[0028]
On the other hand, in the case of the present embodiment shown in FIG. 3, even if the outer surface side is subjected to a compression action due to the presence of the stress relief grooves 17A and 17B, in particular, due to the presence of the stress relief groove 17A formed on the outer surface, Thus, it can be seen that the wedge-shaped opening 19 is not generated, and it is clearly difficult for the grease to enter. On the other hand, in FIG. 10, due to the presence of the stress relief groove 17A, no gap is generated inside the boot even when the boot outer surface side is compressed. This is because the load is absorbed and relaxed by the deformation of the shape of the stress relief groove 17A.
[0029]
In the present embodiment, as in the non-divided type (see FIG. 10), a plurality of stress relief grooves may be formed along the generatrix on the outer peripheral surface and / or the inner peripheral surface other than the divided portion. When it forms in one or both of an outer surface and an inner surface, stress relaxation of a thick part can be performed more effectively and the improvement of a division part sealability can be anticipated more.
[0030]
Next, the usage mode of the boot of the said Example is demonstrated (refer FIG. 9 etc.).
[0031]
In the same manner as in the prior art, the large-diameter ring portion 13 is fitted to the joint housing 21 of the universal shaft joint by closing the divided portions D1 and D2 by engaging the occlusal convex portion 5 with the occluded portion 9 from the expanded state. The small diameter ring portion 11 is fitted to the joint shaft 23 and the boot 1 is assembled to the universal shaft joint. In addition, grease is enclosed in the bearing portion (bearing portion) of the universal shaft joint.
[0032]
While grasping the occlusal convex part 5 of the division part D1 by hand, the occlusion groove 7 of the part to be occluded 9 is sequentially pushed from the large diameter ring part 13 side or the small diameter ring part 11 side. The bulging and engaging portion 3 of the occlusal ridge portion 5 is forcibly expanded between the open end portions of the occlusal groove 7 of the occluded portion 9 and is engaged with the keyhole-shaped occlusal groove 7. At this time, since the sandwiched insert 6 is embedded in the occlusal ridge 5 and rigidity in the insertion direction is given, the occlusion workability is good. Further, between the open end portions of the occlusal groove 7, the spring force is applied in the closing direction by the sandwiching insert 8 and the occlusal portion 9 is formed of a rubber-like elastic body. The general portion of the portion 5 is sandwiched between the open end portions of the occlusal groove 7 in a close state, and a sealing function is imparted to the occlusal portion, and a large retaining force is generated. The large-diameter ring portion 13 is normally fixed securely with a metal fastening band 25.
[0033]
At this time, it is desirable to perform the occlusion work by applying silicone oil to one or both of the occlusal convex part 5 and the part to be occluded 9 in order to improve the occlusion workability and the sealing performance of the occlusion part.
[0034]
In order to replace the boot after long-term use, the fastening band 25 of the large-diameter ring portion 13 is removed, and both ends of the split portion of the large-diameter ring portion 13 are gripped by hand, When a force is applied so as to tear both sides, the occlusal state between the occlusal protruding ridge portion 5 and the occluded portion 9 is forcibly released. In this way, the boot can be expanded and attached / removed.
[0035]
When the boot 1 is bent, when the outer surface is compressed, the stress relief groove 17A is formed along the opposing end edge of the thick portion D1, and therefore it is difficult for grease to enter.
[0036]
10 to 12 show an embodiment in which the present invention is applied to a non-split type boot.
[0037]
In the present embodiment, a plurality of stress relief grooves 17 </ b> A (six in the illustrated example) are formed on the outer surface along the bus line from the small diameter ring portion 11 to the large diameter ring portion 13 of the boot bellows portion 15.
[0038]
Due to the presence of the multiple stress relief grooves 17A, it is possible to efficiently absorb and alleviate the compression / tension load generated when the boot is bent. Therefore, the durability of the boot can be improved.
[0039]
That is, when the stress relief groove 17A is formed, when a compression load is generated on the groove forming side (inner surface and / or outer surface), the groove shape of the stress relief groove 17A changes so as to be contracted from both sides. Therefore, the compression load can be effectively absorbed and relaxed. Conversely, when a tensile load is generated on the groove forming side, the shape of the stress relief groove 17A changes so as to open on both sides. Therefore, the tensile load can be effectively absorbed and relaxed.
[0040]
The stress relief groove 17A only needs to be formed at least on the inner surface and / or the outer surface, and the groove shape may be any of a square groove, a trapezoidal groove, a V-shaped groove, a round groove, etc., as shown in FIG. There may be. Due to the presence of the stress relief groove 17A, the stress relief groove absorbs and relaxes the compression / tension load generated when the boot is bent. For this reason, further improvement in boot durability can be expected.
[0041]
Further, as shown in FIG. 12A, when the stress relief grooves 17A are equally divided as shown in the present embodiment and four or more stress relief grooves 17A are formed as shown in the figure (six in the figure), even when subjected to a compression action. As shown in FIG. 12 (B), the cross-sectional shape of the bellows portion is a shape close to a perfect circle (regular polygon), and stress relaxation is possible regardless of the bending direction, and further improvement in boot durability is expected. it can.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a universal joint boot according to an embodiment of the present invention.
FIG. 2 is an inner arrow view of the inner surface viewed from the large-diameter ring portion side.
FIG. 3 is a cross-sectional view of a main part showing a seal fastener structure.
4 is a perspective view of the sandwiched insert in FIG. 3. FIG.
5 is a perspective view of the sandwiching insert in FIG. 3. FIG.
FIG. 6 is a front view for explaining the action during the bending movement of the boot.
7 is an end view taken along line 7-7 of FIG.
FIG. 8 is a cross-sectional view of the main part when the outer surface is compressed during the bending movement of the boot in the conventional example.
FIG. 9 is a cross-sectional view showing how the boot is mounted.
FIG. 10 is a perspective view showing an embodiment in which the present invention is applied to a non-split type boot.
FIG. 11 is a cross-sectional view showing various groove shapes of stress relief grooves formed on the outer side of the boot.
12 is a cross-sectional view for explaining a change in cross section during the bending motion of the boot shown in FIG.
[Explanation of symbols]
1: Boot 11: Small diameter ring part 13: Large diameter ring part 15: Bellows part 17A, 17B: Stress relief grooves D1, D2: Divided parts

Claims (7)

In the boot for a universal shaft joint formed of a rubber-like elastic body and having a bellows portion between the small diameter ring portion and the large diameter ring portion,
A universal shaft joint boot, wherein at least one stress relief groove is linearly formed on an inner surface and / or an outer surface along a generatrix line from a small diameter ring portion to a large diameter ring portion of the bellows portion. It is formed of a rubber-like elastic body, and the space between the small diameter ring part and the large diameter ring part is the bellows part,
In a universal joint boot in which a linear divided portion is formed from the small diameter ring portion to the large diameter ring portion, the divided portion is a thick portion, and a seal fastener is disposed.
A universal joint boot according to claim 1, wherein at least one stress relief groove is formed on an inner surface and / or an outer surface along a generatrix from a small diameter ring portion to a large diameter ring portion of the bellows portion. The universal shaft joint boot according to claim 2, wherein the stress relief groove is formed along an outer side of an opposite end edge of one of the thick portions. The universal shaft joint boot according to claim 2 or 3, wherein the stress relief groove is formed on one or both of the outer surface and the inner surface along both sides or one side of the thick portion. The seal fastener is formed along one end edge of the divided portion, and has a belt-like occlusal protruding ridge portion provided with a bulging locking portion at the tip, and a rubber shape along the other end edge of the divided portion. The universal shaft joint boot according to claim 2, 3 or 4, wherein the boot is a structure made of an elastic body and comprising a band-shaped occluded portion provided with an occlusal groove that engages with the occlusal ridge. On the outer periphery of the occlusal groove, a sandwiching insert made of a linear spring material and having a transverse shape with substantially no corners is embedded, and the spring is sandwiched between the opening end portions of the occlusal portion 6. The universal shaft joint boot according to claim 5, wherein a force is applied, and a sandwiched insert having a corrugated flat surface is embedded in the occlusal ridge portion and is made of a linear spring material. The universal shaft boot according to any one of claims 2 to 6, wherein the divided portion bulges inward to form a thick portion.

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