JP2002213484A - Boot for constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve workability when inserting a boot band into a fixing part of a boot, surely prevent slip-out of the boot band, and enhance flexibility of design for the boot band. SOLUTION: This boot 20 is fixed to a constant velocity universal joint by fastening the fixing part 23 by the boot band 30 by fitting the cylindrical fixing part 23 to a boot installing part of a joint constituting member. In this case, a projecting parts 26 of the fixing part 23 are arranged in the circumferential directional three places, and small diameter parts 27, having a diameter smaller than the projecting parts 26 are formed in the radially directional facing opposed positions of the projecting parts 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boot mounted on a constant velocity universal joint.

[0002]

2. Description of the Related Art A bellows-shaped boot is mounted on a constant velocity universal joint for the purpose of preventing leakage of grease sealed inside the joint and preventing foreign matter from entering the joint. Both ends of the boot are fitted to an outer joint member and a shaft, respectively, which are joint constituent members of the constant velocity universal joint, and both ends are fixed to each other by tightening both ends of the boot with a boot band. The boots for constant velocity universal joints are generally classified into rubber boots made of a rubber material such as chloroprene rubber (CR) and resin boots made of a resin material, and any type of boot can be used depending on the application. I have.

[0003] Regardless of the rubber boot or the resin boot, the mounting of the boot to the joint constituting member is provided at both ends of the boot as shown in FIG. An annular boot band 130 is inserted into the outer periphery of the cylindrical fixing portion 123, and the boot band 130
Is fitted in the band mounting groove 125 formed in the outer periphery of the fixing portion 123, the fixing portion 123 is fitted to the outer periphery of the joint component member, and then the boot band 130 is reduced in diameter to tighten the fixing portion 123 to the inner diameter side. This is done by:

On the outer periphery of the fixing portion 123, a band mounting groove 1 is provided.
A flange-like protrusion 126 is formed on the boot end face side of the boot 25 and an engaging portion 128 is formed on the opposite side of the band mounting groove 125. The boot band 130 fitted into the band mounting groove 125 has the protrusion 126
Is restrained from both sides in the axial direction. As the protruding portions 126 on the end face side of the boot 120, an annular one shown in FIG. 13 and ones arranged at four positions in the circumferential direction shown in FIG. 14 are known.

[0005]

When the boot band 130 is inserted from the end face side of the boot 120 to the outer periphery of the fixing portion 123 as shown in FIG.
There is a possibility that the inner circumference of 30 may interfere with the outer circumference of the protruding portion 126 and hinder the operation of inserting the boot band 130. In particular, resin boots generally have lower elasticity than rubber boots, so the protruding portion 126 is easily caught, and such interference often causes a problem.

This problem can be solved by reducing the height (radial width) of the protruding portion 126 or by increasing the inner diameter of the boot band 130. There is a concern that the band 130 may come off.
However, there is a problem that the degree of freedom in designing is reduced.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve workability when inserting a boot band into a fixing portion of a boot, reliably prevent the boot band from coming off, and increase the degree of freedom in designing the boot band. I do.

[0008]

In order to achieve the above object,
In the present invention, a boot band in which a fixing portion provided with a band mounting groove and a protruding portion formed on the boot end face side of the band mounting groove is fitted to a boot mounting portion of the joint constituent member and inserted into the outer periphery of the band mounting groove. By reducing the diameter and tightening the fixing part, in the constant velocity universal joint boot attached to the joint constituent member, the protrusions of the fixing part are arranged at a plurality of positions in the circumferential direction, and at the positions opposed to the protrusions in the radial direction. A small diameter portion having a smaller diameter than the projecting portion is formed.

In this way, if the protrusions are arranged at a plurality of positions in the circumferential direction, and the small-diameter portions are formed at positions opposed to the protrusions in the radial direction, when the boot band is inserted around the outer periphery of the fixing portion, If the inner circumference is partially close to the small diameter part,
Since the gap between the small-diameter portion and the protruding portion at the position facing the radial direction and the inner periphery of the boot band is enlarged, the boot band can be inserted while avoiding interference with the protruding portion. Therefore, it is possible to realize a smooth insertion work without lowering the height of the protruding portion or increasing the inner diameter of the boot band, and to surely prevent the boot band from coming off, and at the same time, to freely design the boot band. The degree can be greatly increased.

In this case, in order to surely prevent the interference between the boot band and the projecting portion, it is desirable that the dimension between the projecting portion and the small diameter portion which are opposed to each other be equal to or smaller than the inner diameter of the boot band before the diameter reduction.

It is desirable that the protrusions are equally arranged in the circumferential direction. However, if the protrusions are equally arranged at even positions, the protrusions and the small diameter portion cannot be opposed to each other in the radial direction. Therefore, the protrusions are equally arranged at three or more odd-numbered positions.

If the protrusions are equally arranged at three places and the length in the circumferential direction is set so that the central angle is 90 ° or less, all the protrusions can be opposed to the small diameter portion.

If the cross-sectional shape of the outer peripheral surface of the protruding portion is an arc shape, it is possible to more reliably prevent the protrusion from being caught by the inner periphery of the annular boot band. From the same viewpoint, it is desirable to gradually reduce the diameter of both sides in the circumferential direction of the protrusion.

When the height of the protruding portion is 0.5 to 1.2 mm, the effect of preventing the boot band from falling off can be sufficiently ensured.

When the boot is formed of a thermoplastic elastomer, for example, the surface hardness of the boot is determined according to JIS.
When the durometer D according to K6253 is 35 or more, it is difficult to elastically deform the protruding portion, and it becomes difficult to insert the boot band over the protruding portion, thereby increasing the utility of the present invention.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
A description will be given based on FIG.

FIG. 1 shows a constant velocity universal joint 10 to which a bellows-shaped boot 20 is attached using a boot band 30. The illustrated constant velocity universal joint 10 includes an outer joint member 12 having a plurality of guide grooves 11 formed in the inner peripheral surface in the axial direction, and an inner joint member 14 having a plurality of guide grooves 13 formed in the outer peripheral surface in the axial direction. , A plurality of balls 15 arranged on a ball track formed by the cooperation of the guide grooves 11 and 13, a retainer 16 for holding the balls 15 in the same plane, and an inner periphery of the inner joint member 14. And a shaft 17 connected to be able to transmit torque by serrations, splines, etc., as main joint components. The outer joint member 12 includes a cup-shaped mouth portion 12a and a shaft-shaped stem portion 12b. Of course, the configuration of the constant velocity universal joint 10 is not limited to this, and other types (double offset type, tripod type, cross groove type, etc.) other than those shown in the drawings as long as the boot 20 covers the joint opening. The constant velocity universal joint described in (2) can also be used.

The boot 20 is fixed to each outer periphery of the outer joint member 12 and the shaft 17 using a boot band 30. The boot 20 includes a bellows portion 21 and cylindrical fixing portions 22 and 23 provided on both sides of the bellows portion 21, and the fixing portion 22 provided on one end side of the boot 20, for example, on the large diameter end side. Is fixed to the boot attaching portion 40a of the outer joint member 12 at the other end (small diameter end).
Are fixed to the boot mounting portions 40b of the shaft 17, respectively. The boot 20 may be a rubber boot or a resin boot.

As shown in FIG. 2, an annular engagement groove 41 is formed on the outer periphery of the boot mounting portion 40b of the shaft 17, and annular projections 42 are formed on both axial sides of the engagement groove 41.
Are formed. In the drawings, the engagement groove 41 is formed in a circular arc shape in cross section, but it may be formed in a cylindrical surface shape.

An annular convex portion 24 is integrally formed on the inner periphery of the fixed portion 23 on the small diameter end side of the boot 20. An annular band mounting groove 25 is formed on the outer peripheral surface of the fixing portion 23, and the boot mounting small diameter end surface side of the band mounting groove 25 (the boot band 3
A flange-shaped protrusion 26 is formed on the “0” insertion side). The band mounting groove 25 is defined by a protruding portion 26 and a radial locking portion 28 axially opposed to the protruding portion 26, and the boot band 3 is formed between the protruding portion 26 and the locking portion 28.
0 is fitted.

As shown in FIG. 4, the protrusions 26 are formed at, for example, three equally-spaced positions in the circumferential direction. A small diameter portion 27 having an outer diameter smaller than that of the protrusion 26 is formed between the adjacent protrusions 26. The outer peripheral shape of each projection 26 is formed in an arc shape, but their centers of curvature do not coincide,
Each is located at a position displaced to the outer diameter side from the center O of the boot 20. Each small-diameter portion 27 has an arc shape having a center of curvature at the center O of the boot 20, and its radius of curvature is larger than that of the protrusion 26. Therefore, the height h (radial width) of each protrusion 26 on both circumferential sides is gradually reduced. At this time, it is desirable that both ends of the protruding portion 26 and the small-diameter portion 27 adjacent thereto are connected smoothly.

The height h of the projection 26 (the height of the highest portion of the projection 26) is desirably set to 0.5 to 1.2 mm. When h is smaller than 0.5 mm,
Although the workability when the boot band 30 is inserted into the fixing portion 23 of the boot 20 is improved, the effect of preventing the band from coming off may be insufficient. If h is larger than 1.2 mm, workability at the time of insertion may be impaired, and the degree of freedom in designing the boot band 30 may be reduced. On the other hand, a band retaining effect corresponding to this may be expected. Can not.

The outer diameter of the small diameter portion 27 can be set arbitrarily within a range smaller than the outer diameter of the protruding portion 26. In this embodiment, the outer diameter of the band mounting groove 25 is the same as the outer diameter of the groove bottom. The case is illustrated.

When the protrusions 26 are formed at three positions in the circumferential direction as in the illustrated example, the protrusions 26 are formed so that the circumferential area thereof is within 90 °. That is, the center angle θ formed between the center O of the boot and both ends of the protruding portion 26 is formed in a range where the angle θ is 90 ° or less. As a result, the small-diameter portion 27 is located at a position in the radial direction opposite to each of the protruding portions 26 (particularly, the thick portion). In this case, the dimension D between the outer periphery of the protruding portion 26 and the outer periphery of the small-diameter portion 27 which are opposed to each other is set.
(In this embodiment, the dimension between the outer periphery of the portion having the largest height h of the protruding portion 26 and the outer periphery of the small diameter portion 27) is set to be equal to or less than the inner diameter of the boot band 30 before the diameter reduction. (The most protruding portion in the case of the illustrated example) The protruding portions 26 can be arranged at three or more locations as long as the small-diameter portion 27 is formed at a position opposed to each protruding portion 26 in the radial direction. However, if the protrusions 26 are equally arranged at a plurality of positions in the circumferential direction, the protrusions 26 cannot be opposed to the small-diameter portion 27 in the radial direction. Therefore, the protrusions 26 are formed at odd-numbered positions.

The mounting of the boot 20 is performed in the following procedure. First, as shown in FIG.
7 into the outer periphery of the boot attaching portion 40b, and the fixing portion 2
3 the protrusion 24 on the inner circumference is engaged with the engagement groove 4 of the boot mounting portion 40b.
1 and position adjustment is performed. Next, an annular boot band 30 is axially inserted around the outer periphery of the fixing portion 23 formed at the small diameter end of the boot 20. At this time, as shown in FIG. 5, the boot 20 and the boot band 30 are eccentric, and the boot 20 is inserted while the inner circumference of the boot band 30 is partially brought close to the small diameter portion 27 (including the case where the boot 20 is brought into sliding contact). If
Since the gap between the outer periphery of the protruding portion 26 facing the small diameter portion 27 and the inner periphery of the boot band 30 is enlarged, the interference between the inner periphery of the boot band 30 and the protruding portion 26 is avoided to make the boot band smooth. 30 can be inserted. Similarly, even if one of the boot band 30 and the boot 20 is inserted with the other tilted with respect to the other, the same can be smoothly inserted.

After performing the above operations, the boot band 30
Is reduced, and the fixing portion 23 is tightened to the inner diameter side. As a result, as shown in FIG. 3, the fixing portion 23 is elastically deformed and closely adheres to the boot attaching portion 40b, and the protrusion 42 of the boot attaching portion 40b bites into the inner periphery of the fixing portion 23, so that good sealing performance and reliable The retaining effect is secured.

As described above, according to the present invention, the height h of the protrusion 26 on the boot 20 side is set to a value necessary and sufficient to prevent the boot band 30 from coming off,
The work of inserting into the outer periphery can be performed smoothly, and both the effect of preventing the boot band 30 from coming off and the workability of the work of inserting can be achieved. Further, since the inner diameter of the boot band 30 can be made smaller than that of the conventional product, the degree of freedom in designing the boot band 30 is improved.

Particularly, the resin boot is inferior to the rubber boot in elasticity.
When it interferes with, it is easy to cause a decrease in insertion workability,
Particularly remarkable effects can be obtained by the present invention. Resin boots are generally thermoplastic elastomers (especially polyester-based)
According to the present invention, even if the hardness (durometer D) according to JIS K6253 is 35 or more, both the retaining property and the insertion workability can be achieved.

In the above description, the boot band 30
The fixing portion 23 is externally fitted to the boot attaching portion 40b before insertion, and then the boot band 30 is extrapolated to the fixing portion 23 and the boot band 30 is tightened. After being extrapolated to 23, the fixing part 23 with a boot band may be externally fitted to the boot mounting part 40 b of the shaft 17.

FIG. 6 shows a mounting structure of the boot 20 on the large-diameter end side. Similarly to the above-described small-diameter end mounting structure, the large-diameter end fixing portion 22 of the boot 20 has a convex portion 24 on the inner periphery thereof, a band mounting groove 25 on the outer periphery thereof, and a projecting portion 2.
6, and the locking portion 28 are respectively formed. Further, a boot mounting portion 40a having an engagement groove 41 and a projection 42 is formed near the opening on the outer periphery of the mouth portion 12a of the outer joint member 12. Also in this case, the same effect as described above can be obtained by forming the protruding portion 26 into the shape shown in FIG.

As the boot band 30, various types can be used. FIG. 7 shows a so-called one-touch type boot band, in which a band member 31 made of a band-shaped metal material is curved in a ring shape and joined in a state where both ends are overlapped, and one surface of the overlap portion 32 is provided. Further, a lever member 33 made of a metal material thicker and more rigid than the band member 31 is fixed thereto. On the inner surface of the band member 31, for example, a protrusion 34 can be formed by bending a required portion of the band member 31 inward.

After the lever member 33 is forcibly turned back using the leverage action, as shown in FIG.
3 is superimposed on the outer surface of the band member 31,
Fix with. By folding back the lever member 33, the annular portion of the band member 31 is reduced in diameter, and the fixed portions 22, 23 are fixed.
Is given a predetermined tightening force. The structure of the stopper 35 is arbitrary. For example, as shown in FIGS. 9A and 9B, a metal piece having a U-shaped cross section can be fixed to a predetermined portion of the band member 31. In this case, the lever member 33
Is fixed by bending both sides of the U-shaped metal piece and overlapping the outer surface of the lever member 33. After the lever member 33 is folded, a gap is formed near the folded portion 31a. However, if the protrusion 34 is provided on the inner surface of the band member, the gap is filled with the protrusion 34, so that the seal is formed. There is no decrease in the performance.

FIGS. 10 and 11 show another example of the boot band 30. FIG. FIG. 10 shows what is called an omega band. After the boot band 30 is inserted into the outer periphery of the fixing portions 22 and 23, the overhang portion 36 (shown by a two-dot chain line).
The diameter of the annular portion 37 is reduced by caulking the root portion of
2 and 23 are tightened. FIG. 11 shows what is called an annular band, which is composed of only a cylindrical ring portion 38. Normally, the upper portion 38 is plastically deformed mechanically or electrically to reduce its diameter, thereby obtaining a tightening force.

[0034]

According to the present invention, the boot band can be smoothly inserted into the outer periphery of the fixed portion of the boot while avoiding interference between the inner periphery of the boot band and the projecting portion. Therefore, while the height of the protruding portion on the boot side is increased to reliably prevent the boot band from coming off from the fixing portion, the work of inserting the boot band into the outer periphery of the boot can be performed smoothly, and the boot band can be removed. It is possible to achieve both the stopping effect and the workability of the insertion work. Further, the inner diameter of the boot band can be made smaller than that of the conventional product, and the design flexibility of the boot band is improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a constant velocity universal joint on which a boot for a constant velocity universal joint is mounted.

FIG. 2 is a cross-sectional view showing a boot mounting structure on a boot small end side.

FIG. 3 is a cross-sectional view illustrating a boot mounting structure on a small boot end side.

FIG. 4 is a front view of a fixing portion of the boot.

FIG. 5 is a front view showing a step of inserting the boot band into the outer periphery of the fixing portion.

FIG. 6 is a cross-sectional view showing a boot mounting structure on a boot large end side.

FIG. 7 is a front view showing an example of a boot band.

FIG. 8 is a front view of the boot band showing a state in which the lever member is folded back.

FIG. 9 is a cross-sectional view showing a step of fixing the lever member with the stopper.

FIG. 10 is a front view showing an example of a boot band.

FIG. 11 is a front view showing an example of a boot band.

FIG. 12 is a sectional view showing a step of inserting a boot band into a boot.

FIG. 13 is a front view showing a conventional fixing portion.

FIG. 14 is a front view showing a conventional fixing portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Constant-velocity universal joint (joint constituent member) 12 Outer joint member (joint constituent member) 17 Shaft 20 Boot 22 Fixed part (large end side) 23 Fixed part (small end side) 25 Band mounting groove 26 Projection part 27 Small diameter part 30 Boot band

Claims (10)

[Claims] 1. A boot band in which a fixing portion having a band mounting groove and a projecting portion formed on a boot end face side of the band mounting groove is fitted to a boot mounting portion of a joint component, and is inserted into the outer periphery of the band mounting groove. In the constant velocity universal joint boot attached to the joint constituting member by reducing the diameter of the fixed portion, the protrusions of the fixed portion are arranged at a plurality of positions in the circumferential direction, and the positions of the protrusions are opposed to each other in the radial direction. A constant-velocity universal joint boot, wherein a small-diameter portion smaller in diameter than the protruding portion is formed. 2. The constant velocity universal joint boot according to claim 1, wherein a dimension between the protruding portion and the small diameter portion which are opposed to each other is equal to or less than an inner diameter of the boot band before diameter reduction. 3. The boot for a constant velocity universal joint according to claim 1, wherein the projecting portions are equally arranged at three or more odd-numbered positions. 4. The boot for a constant velocity universal joint according to claim 1, wherein the protrusions are equally arranged at three places, and the length in the circumferential direction is set so that the central angle is 90 ° or less. 5. The boot for a constant velocity universal joint according to claim 1, wherein a cross-sectional shape of an outer peripheral surface of the projecting portion is an arc shape. 6. The boot for a constant velocity universal joint according to claim 5, wherein the diameter of both sides in the circumferential direction of the projecting portion is gradually reduced. 7. The boot for a constant velocity universal joint according to claim 1, wherein the height of the projection is 0.5 to 1.2 mm. 8. The boot for a constant velocity universal joint according to claim 1, wherein the boot is formed of a thermoplastic elastomer. 9. The surface hardness of the boot is JIS K625.
9. The boot for a constant velocity universal joint according to claim 8, wherein the durometer D according to 3 is 35 or more. 10. A constant velocity universal joint to which the boot for a constant velocity universal joint according to claim 1 is attached.