JP4114028B2 - Universal joint boots - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a universal joint boot used for covering and protecting a bending operation portion of a universal joint.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a universal joint boot 1 shown in FIG. 2 is known and configured as follows.
[0003]
That is, first, as shown in the figure, a boot body 2 made of a flexible material having a bellows portion 3 composed of a straight portion 4 and a rounded portion 5 is provided, and a small-diameter side end portion 6 of the boot body 2 is provided. The clamp 7 is attached to the operating shaft 9 of the universal joint 8, and the large-diameter side end portion 10 of the boot body 2 is attached to the outer ring portion (not shown) of the universal joint 8 via the adapter 11. . The adapter 11 is made of metal, and is provided with a caulking portion 12 at one end thereof, and the large-diameter side end portion 10 of the boot body 2 is caulked and fixed to the caulking portion 12.
[0004]
This type of universal joint boot 1 has a substantially approximate shape determined by the dimensions of the universal joint 8 (dimensions a and b in FIG. 2) or the dimensions of the mounting space. As shown in FIG. The bellows part 3 must be designed so that the bellows part 3 does not interfere with the gauge, the inner ring part, the outer ring part or the like inside the universal joint 8 when it is bent at a high angle.
[0005]
Therefore, for these reasons, (1) the radius dimension (radius) of the rounded portion 5 cannot be set large, and (2) the length of the straight portion 4 cannot be set long. Then, there is an inconvenience that it is difficult to improve the bending fatigue resistance.
[0006]
Further, if the two points (1) and (2) are to be included in the shape of the bellows part 3, the initial inclination angle θ of the straight part 4 with respect to the operating shaft 9 is set small. Therefore, the interference start angle of the straight portion 4 with respect to the operating shaft 9 becomes small, and the interference start is quickened, so that the wear resistance may be lowered.
[0007]
[Problems to be solved by the invention]
In view of the above points, the present invention can improve the bending fatigue resistance of a boot body integrally provided with a straight portion and a rounded portion, and can also improve the wear resistance of the boot body. An object of the present invention is to provide a universal joint boot capable of extending the length.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a universal joint boot according to the present invention includes a small-diameter side end portion attached to an operating shaft of a universal joint, and a large-diameter side end portion attached to an outer ring portion of the universal joint via an adapter. In a universal joint boot having a boot body integrally provided with a straight portion and a rounded portion therebetween, the universal joint boot has a shape that bulges outward in the radial direction when the universal joint boot is in an initial motion posture with a zero bending angle. The swelling or curvature is set in the straight portion of the boot body.
[0009]
Like the universal joint boot of the present invention having the above-mentioned configuration, the straight portion of the flexible boot body is directed radially outward when the universal joint boot is in the initial motion posture with zero bending angle. When the bulge or curvature of the bulging shape is set, the straight part is set longer than the conventional boot as a boot to be installed in a fixed mounting space, so the distortion to the local part during bending is alleviated. Is done.
[0010]
At the same time, since the initial inclination angle of the straight portion with respect to the operating shaft is set to be larger than before, the interference start angle of the straight portion with respect to the operating shaft is increased and the start of interference is delayed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0012]
FIG. 1 shows a cross section of a universal joint boot 1 according to this embodiment, and this boot 1 is configured as follows.
[0013]
That is, first, as shown in the figure, there is provided a boot body 2 made of a flexible material having a bellows portion 3 composed of a straight portion (also referred to as a tubular portion) 4 and a rounded portion (also referred to as a reversing portion) 5. The end 6 of the small diameter side of the boot body 2 is attached to the operating shaft 9 of the universal joint 8 by the clamp 7, and the end 10 of the large diameter side of the boot body 2 is fixed to the adapter 11. It attaches to the outer ring | wheel part (not shown) of the universal joint 8 via.
[0014]
In the boot body 2, the bellows portion 3 composed of the straight portion 4 and the rounded portion 5 is designed to have a relatively thin wall thickness so as to improve its fatigue durability life, and has a relatively thick small diameter at one end thereof. The side end 6 is provided and the other end is also provided with a relatively thick large-diameter side end 10, and the whole is a flexible material or rubber-like elastic material made of a predetermined rubber or thermoplastic elastomer. Are integrally molded.
[0015]
The straight portion 4 is formed in a tapered shape so that the diameter dimension gradually increases as the distance from the small diameter side end portion 6 is kept substantially constant, while the thickness portion is substantially constant. As shown in the figure, when the boot 1 is in the initial motion posture (free state at the time of wearing) with a bending angle of zero, a bulge or curvature (bulging shape, curved shape or cross-sectional circle) that bulges outward in the radial direction. 13 is also set. Therefore, the cross-sectional shape of the straight portion 4 is not a straight shape but an arc shape, and is formed so that the diameter dimension once increased becomes smaller again as the distance from the small diameter side end portion 6 increases. The actual size of the curvature is preferably in the range of R25 to 200 mm, and the bulge size f with respect to the straight line (dotted line in FIG. 1) connecting the small diameter side end portion 6 and the minimum inner diameter portion of the rounded portion 5 is the actual size. A range of 0.5 to 10 mm is preferable.
[0016]
The rounded portion 5 is formed in a substantially U-shaped cross section, and is formed into a shape that is largely recessed and inverted toward the inner side of the universal joint 8 so that the large-diameter side end portion 10 is positioned on the outer peripheral side of the straight portion 4. Has been.
[0017]
A clamp groove 6a for fitting a band-type or caulking-type clamp 7 is provided on the outer peripheral surface of the small-diameter side end portion 6, and the clamp 7 is fitted into the clamp groove 6a.
[0018]
The adapter 11 is first provided with a cylindrical press-fitting portion 11a that is press-fitted into the outer periphery of the outer ring portion of the universal joint 8, and is directed radially inward from one axial end of the press-fitting portion 11a. An inward flange-shaped abutting portion 11b that is abutted against the end face of the outer ring portion is provided, and a cylindrical rising portion 11c is provided from the inner peripheral end of the abutting portion 11b toward one side in the axial direction. In addition, a crimping portion 12 that holds the large-diameter side end portion 10 of the boot body 2 is provided at the tip thereof. The adapter 11 is integrally formed of a predetermined metal from the press-fitting portion 11a to the crimping portion 12.
[0019]
In the universal joint boot 1 having the above-described configuration, the small-diameter side end portion 6 of the boot main body 2 is attached to the operating shaft 9 of the universal joint 8 by the clamp 7 and the large-diameter side end portion 10 of the boot main body 2 as described above. Is attached to the outer ring portion of the universal joint 8 via the adapter 11 to cover and protect the bending operation portion of the universal joint 8 for the propeller shaft. The above-described configuration has the following effects. is doing.
[0020]
That is, first, as described above, the straight portion 4 of the boot body 2 made of a flexible material has a bulge or curvature 13 of a shape that bulges outward in the radial direction when the boot 1 is in the initial motion posture with a zero bending angle. Therefore, when the mounting space is constant, it is possible to set the length of the straight portion 4 longer than the conventional one. Therefore, since the distortion to the local part at the time of a bending operation can be relieved, the bending fatigue resistance of the boot body 2 made of a flexible material can thereby be improved.
[0021]
Similarly, the straight portion 4 of the boot body 2 made of a flexible material is set with a bulge or curvature 13 having a shape that bulges outward in the radial direction when the boot 1 is in the initial motion posture with a zero bending angle. Therefore, it is possible to set the initial inclination angle of the straight portion 4 with respect to the operating shaft 9 to be larger than the conventional one. Therefore, since the interference start angle of the straight portion 4 with respect to the operating shaft 9 can be increased and the start of interference can be delayed, this can improve the wear resistance of the boot body 2 made of a flexible material.
[0022]
Therefore, it is possible to provide the universal joint boot 1 having a long product life.
[0023]
【The invention's effect】
The present invention has the following effects.
[0024]
That is, in the universal joint boot of the present invention having the above-described configuration, the flexible joint boot body is radially outward when the universal joint boot is in the initial motion posture with a zero bending angle. Since the bulge or curvature of the shape that bulges toward is set, it is possible to set the length of the straight portion longer than before when the mounting space is constant. Therefore, since the distortion to the local part at the time of bending operation can be relieved, the bending fatigue resistance of the boot body made of a flexible material can thereby be improved.
[0025]
Similarly, a bulge or curvature of a shape that bulges outward in the radial direction when the universal joint boot is in the initial motion posture with a zero bending angle is set in the straight portion of the flexible boot body. For this reason, it is possible to set the initial inclination angle of the straight portion with respect to the operating shaft larger than that of the conventional art. Accordingly, the interference start angle of the straight portion with respect to the operating shaft can be increased to delay the start of the interference, thereby improving the wear resistance of the flexible boot body.
[0026]
Therefore, it is possible to provide a universal joint boot having a long product life and excellent durability.
[Brief description of the drawings]
1 is a cross-sectional view of a universal joint boot according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a universal joint boot according to a conventional example. FIG. 3 is a cross-sectional view showing an operating state of the universal joint boot. Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Universal joint boot 2 Boot body 3 Bellow part 4 Straight part 5 Round part 6 Small diameter side edge part 6a Clamp groove 7 Clamp 8 Universal joint 9 Actuation shaft 10 Large diameter side edge part 11 Adapter 11a Press-fit part 11b Butting part 11c Standing Raising part 12 Caulking part 13 Swelling or curvature

Claims (1)

A small-diameter end (6) attached to the operating shaft (9) of the universal joint (8) and a large-diameter end (10) attached to the outer ring portion of the universal joint (8) via the adapter (11). In the universal joint boot (1) including the boot body (2) in which the straight portion (4) and the rounded portion (5) are provided integrally with each other,
When the universal joint boot (1) is in the initial motion posture with a zero bending angle, the bulge or curvature (13) of the shape bulging outward in the radial direction is applied to the straight portion (4) of the boot body (2). A universal joint boot characterized by being set.

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