JP2001059527A - Universal joint boot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a boot from breaking by abrasion by arranging a bending part on an inclining part in a boots wherein a crest part of a bellows part and the inclining part of a small diameter side are brought into contact with each other. SOLUTION: A bending part 8 is disposed on an inclining part 7 with which a crest part 5 of a boots 1 is brought into contact, and the inclining part 7 is formed by assembling an outside inclining part 7a with an outside inclining part 7a which are alternately continuously formed on the border of the bending part 8. An inclining angle θ1 of the outside inclining part 7a with respect to a center axis 0 of a free condition of the boots 1 is set larger than an inclining angle θ2 of the inside inclining part 7b with respect to the center axis 0. When the crest part 5 and the inclining surface part 7 are brought into contact with each other while bending the boots 1 at a wide angle, the inclining surface part 7 is smoothly bent at the bending part 8 in a compression side on a circumference. Accordingly, contact pressure is suppressed in a low level, and breakage is prevented by suppressing generation or advance of abrasion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a universal joint boot used for covering and protecting an operating portion of a universal joint.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a bellows portion 54 is provided between a small diameter side mounting portion 52 and a large diameter side mounting portion 53, and the small diameter side mounting portion 52 is connected to the universal joint 21. And a fixing portion 53 on the large-diameter side is fixed to the outer periphery of the outer ring portion 23 of the universal joint 21 to cover and protect the operating portion 24 of the universal joint 21. A universal joint boot 51 is known.

[0003] The boots 51 are excellent in durability, functionality and recyclability in terms of material compared to conventional rubber boots. Since the rigidity is higher than that of rubber boots, the following inconveniences are caused.

That is, as shown in FIG. 3, when the boot 51 is bent at a wide angle with the operation of the universal joint 21, the peak 55 of the bellows 54 and the slope 56 located on the small diameter side thereof are formed. On the circumferential compression side, they may come into contact with each other.
The contact pressure causes wear at the contact portion, and the boot 51 may be damaged at the contact wear portion. The magnitude of the contact surface pressure tends to increase as the boot 51 bends at a wide angle and as the boot 51 becomes smaller.

[0005]

SUMMARY OF THE INVENTION In view of the above, the present invention has been made in consideration of the above circumstances, even when a boot is bent at a wide angle and a peak portion in the bellows portion and a slope portion located on the small diameter side come into contact with each other. It is an object of the present invention to provide a universal joint boot capable of suppressing the contact pressure of the universal joint, thereby preventing the boot from being worn and damaged at the contact portion.

[0006]

In order to achieve the above object, a boot for a universal joint according to claim 1 of the present invention has a bellows portion between a small-diameter side mounting portion and a large-diameter side mounting portion. In a boot for a universal joint in which a peak portion of the bellows portion and a slope portion located on a small diameter side thereof may come into contact with each other at the time of the bending operation of the boot, a bent portion is provided on the slope portion where the peak portion contacts. It is characterized by the following.

According to a second aspect of the present invention, there is provided a boot for a universal joint according to the first aspect of the present invention, wherein the slope provided with the bent portion has an outer slope continuous with the bent portion as a boundary. And a combination of the inner slope portion and the inner slope portion, and the inclination angle of the outer slope portion with respect to the center axis in the free state of the boot is set to be larger than the inclination angle of the inner slope portion. is there.

[0008] When the bent portion is provided on the slope portion where the peak contacts, as in the universal joint boot according to the first aspect of the present invention having the above configuration, the boot bends at a wide angle to form the peak. When the slope portion comes into contact with each other, the slope portion is smoothly bent at the bent portion on the compression side on the circumference, so that the magnitude of the generated contact pressure can be reduced. As the bent portion that is smoothly bent in this way, it is preferable to form the bent portion in a cross-shaped or substantially rectangular shape in order to add a bending habit to the slope portion in advance. The slope with the bend is
The boot is composed of a combination of an outer slope portion and an inner slope portion that are continuous with each other at the bent portion, and the inclination angle of the outer slope portion with respect to the center axis in the free state of the boot is set to be larger than the inclination angle of the inner slope portion. Is preferred.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a cross section of a boot 1 for a universal joint according to this embodiment, and its operating state, that is, a wide-angle bending state is shown in FIG.

As shown in FIG. 1, the boot 1 is first
It has a bellows portion 4 in which a large number of peak portions 5 and valley portions 6 are alternately arranged in the axial direction. A relatively small-diameter mounting portion (also referred to as a small-diameter mounting portion or a small-diameter mounting portion) 2 having a cylindrical shape is integrally provided, and the other end in the axial direction on the opposite side (the upper and lower sides in the figure; A relatively large-diameter mounting portion (also referred to as a large-diameter mounting portion or a large-diameter mounting portion) 3, which is also cylindrical, is integrally provided on the (diameter side). The bellows portion 4 is formed by integrally providing a slope portion 7 between each peak portion 5 and the valley portion 6, and the diameter of the peak portion 5 and the valley portion 6 is changed from the small diameter side mounting portion 2 to the large diameter side mounting portion. It is formed so as to gradually expand toward the portion 3.

The boot 1 is integrally formed of a resin or a thermoplastic elastomer. As shown, the small-diameter mounting portion 2 is connected to the shaft 22 of the universal joint 21.
And the large-diameter side mounting portion 3 is connected to the universal joint 2.
The outer joint 23 is fixed to the outer periphery of the outer ring part 23 to cover and protect the operating part 24 of the universal joint 21. In addition, the boot 1 is devised as follows since the peak 5 of the bellows 4 and the slope 7 located on the small diameter side thereof may come into contact with each other during the bending operation.

That is, in the example shown in the figure, the peak 5 located on the largest diameter side and the slope 7 located on the smaller diameter side come into strong contact with each other.
An inclined portion 8 having an annular shape is provided on the inclined portion 7 with which the outer inclined portion 7a and the inner inclined portion 7b are continuous with each other with the curved portion 8 as a boundary. It is formed by a combination of and, yet (a state of FIG. 1, i.e. the state of flexion zero) the free state of the boot 1 inclination angle theta ₁ of the outer ramp portion 7a with respect to the central axis 0 at the same center axis 0 is set larger than the inclination angle theta ₂ of the inner inclined portion 7b for, it is formed in cross-section rather shaped or substantially V-shape. The thickness of the outer slope portion 7a is uniform over the entire length, while the thickness of the inner slope portion 7b is formed so as to gradually increase from the inside to the outside, that is, toward the bent portion 8. The bent portion 8 is provided at a portion of the slope portion 7 having a predetermined length, where the peak portion 5 just contacts.

The boot 1 having the above configuration is, for example, a CV
As a J boot, it is mounted on the outer periphery of the operating portion 24 of the universal joint 21 to cover and protect the operating portion 24.
As described above, the bent portion 8 is provided on the slope portion 7 with which the mountain portion 5 contacts, and the slope portion 7 provided with the bent portion 8 is provided.
Are outer slope portions 7 continuous with each other at the bent portion 8.
a and the inner slope portion 7b, and the inclination angle θ ₁ of the outer slope portion 7a with respect to the center axis 0 in the free state of the boot 1 is the inclination angle θ of the inner slope portion 7b with respect to the center axis 0. ₂ , the boot 1 is bent at a wide angle and the ridge 5 and the slope 7 contact each other as shown in FIG. 7 is smoothly bent at the bent portion 8. Therefore,
It is possible to suppress the magnitude of the generated contact pressure to a small value, thereby suppressing the occurrence or progress of abrasion and preventing the boot 1 from being damaged by the abrasion.

In the above-described embodiment, the bent portion 8 is provided only on the slope portion 7 where the peak portion 5 located on the largest diameter side contacts, but the bent portion 8 having the same configuration is located on the smaller diameter side. It may be provided alongside another slope 7.

[0016]

The present invention has the following effects.

First, in the universal joint boot according to the first aspect of the present invention having the above-mentioned structure, the boot for the universal joint in which the peak portion of the bellows portion and the slope portion on the small diameter side thereof come into contact with each other during the bending operation. In the above, since the bent portion is provided on the slope portion, when the boot is bent at a wide angle and the mountain portion and the slope portion come into contact with each other, the slope portion on the compression side on the circumference is smoothly formed at the bent portion. Bendable. Therefore, it is possible to reduce the magnitude of the generated contact pressure, thereby suppressing the occurrence or progress of abrasion, preventing the boot from being damaged by abrasion, and improving its durability. Can be.
Further, even when the boot is rotated at a wide angle in a low-temperature or very low-temperature atmosphere, a smooth rotation can be obtained.

Further, the present invention has the above configuration.
In the universal joint boot according to the universal joint boots in which the peak portion in the bellows portion and the slope portion on the small diameter side thereof come into contact with each other at the time of the bending operation, a bent portion is provided on the slope portion, and the slope portion is The boot is composed of a combination of an outer slope portion and an inner slope portion that are continuous with each other with the bent portion as a boundary, and the inclination angle of the outer slope portion with respect to the center axis in the free state of the boot is set to be larger than the inclination angle of the inner slope portion. Therefore, the slope portion is particularly easily bent, and when the boot is bent at a wide angle and the hill portion and the slope portion come into contact with each other, the slope portion is smoothly bent at the bending portion on the compression side on the circumference. Therefore, it is possible to reduce the magnitude of the generated contact pressure, thereby suppressing the occurrence or progress of abrasion, preventing the boot from being damaged by abrasion, and improving its durability. Can be. Further, as in the case of the first aspect, even when the boot is rotated at a wide angle in a low or very low temperature atmosphere, a smooth rotation can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a mounted state of a universal joint boot according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an operating state of the universal joint boot.

FIG. 3 is a sectional view showing an operating state of a boot for a universal joint according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boot for universal joint 2 Small diameter side attachment part 3 Large diameter side attachment part 4 Bellows part 5 Crest part 6 Valley part 7 Slope part 7a Outside slope part 7b Inside slope part 8 Bend part 21 Universal joint 22 Shaft part 23 Outer ring part 24 Operation Part 0 center axis

Claims (2)

[Claims] A boot (1) having a bellows portion (4) between a small diameter side mounting portion (2) and a large diameter side mounting portion (3).
In a boot (1) for a universal joint, a peak (5) of the bellows (4) and a slope (7) located on the small diameter side thereof may come into contact with each other at the time of bending operation of the bellows (4). A boot for a universal joint, characterized in that a bent portion (8) is provided on the slope portion (7) that makes contact with 5). 2. The universal joint boot according to claim 1, wherein the slope portion (7) provided with the bent portion (8) is continuous with the outer slope portion (7a) at the bent portion (8).
And the inner slope portion (7b), and the inclination angle (θ ₁ ) of the outer slope portion (7a) with respect to the center axis (0) in the free state of the boot ( ₁ ) is the inner slope portion (7b). ) Is set to be larger than the inclination angle (θ ₂ ) of the universal joint.