Boot fixing structure for constant velocity joint

Abstract

To provide a fixing structure of a boot for a constant velocity joint capable of improving sealing performance of an edge part which is a weak point of a seal in the boot for the constant velocity joint having a deformed recessed part on an outer periphery.SOLUTION: The boot has a deformed concave portion (5) corresponding to the concave portion, and the clamp includes a first clamp member (11) which surrounds an outer peripheral surface of the boot and can be reduced in diameter, and a second clamp member (12) which is disposed between the first clamp member and the deformed concave portion and both ends of which are slidable in a circumferential direction with respect to the first clamp member. An angle formed by a line orthogonal to a tangential line of an edge part 6 of the irregular recessed part and a line orthogonal to a tangential line of a part in contact with the edge part of the second clamp member is set to 45 degrees or less, and a peripheral length of the second clamp member is formed to be equal to or more than a peripheral length of a clamp contact surface of the irregular recessed part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fixing structure for a boot for a constant velocity joint, and more particularly to a fixing structure for a boot for a constant velocity joint in which a boot is fixed by a clamp to an irregularly shaped constant velocity joint case having a concave portion on the outer periphery. [Background technology]

[0002] BACKGROUND ART Conventionally, a boot for a constant velocity joint is known that is fixed by a clamp to a constant velocity joint case (hereinafter referred to as a joint case) having an irregular shape with a concave portion on the outer periphery (see, for example, Patent Document 1).

[0003] The boot described in Patent Document 1 is formed with a thick portion corresponding to the concave portion and a thin portion corresponding to the outer peripheral convex portion. The thick portion is formed with an inner peripheral thick portion formed to correspond to the concave portion of the joint case and an outer peripheral thick portion that protrudes outward from the outer peripheral extension line of the thin portion, and the outer peripheral surface of the outer peripheral thick portion is formed with a flat portion perpendicular to the radial center line and chamfered portions on both sides of the flat portion.

[0004] In Patent Document 1, since the clamp is circular and the joint case is irregularly shaped, the boot is fixed by tightening the clamp with the boot shaped to match the shapes of the clamp and the joint case. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-139051 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the device described in Patent Document 1, the boot on the irregularly shaped portion has low rigidity, and the clamp does not apply a radial force when tightened, so the force pressing against the edge of the concave portion is weak. This results in insufficient sealing at the edge, raising concerns about grease leaking from inside the joint. Therefore, since it is difficult to obtain sufficient force to press against the edge, a large amount of tightening is required. However, in order to achieve both clamp strength and sealing performance, it is necessary to control the tightening force within a narrow range at the factory.

[0007] The present invention has been made in consideration of the above circumstances, and has as its object to provide a fixing structure for a boot for a constant velocity joint that improves the sealing performance of the edge portion, which is a weak point of the seal, for a boot for a constant velocity joint that has an irregularly shaped recess on its outer periphery. [Means for solving the problem]

[0008] In order to solve the above problem, the present invention provides a fixing structure for a boot for a constant velocity joint, which fixes an irregularly shaped constant velocity joint case having a concave portion on its outer periphery and a boot fitted to the constant velocity joint case by tightening a clamp, wherein the boot has an irregularly shaped recess corresponding to the concave portion, and the clamp comprises a first band-shaped clamp member which is contractible in diameter and surrounds the outer periphery of the boot, and a second clamp member which is arranged between the first clamp member and the irregularly shaped recess and has both ends which are slidable circumferentially relative to the first clamp member, wherein an angle formed by a line perpendicular to a tangent to an edge portion of the irregularly shaped recess and a line perpendicular to a tangent to a portion of the second clamp member which contacts the edge portion is set to 45 degrees or less, and the circumferential length of the second clamp member is formed to be greater than or equal to the circumferential length of the clamp contact surface of the irregularly shaped recess.

[0009] By configuring it in this manner, when the first clamp member is reduced in diameter to tighten the boot, the first clamp member generates a pressing force only in the radial direction, and as the first clamp member reduces in diameter, both ends of the second clamp member slide closer to each other, generating a force that presses not only the edge portion but the entire irregularly shaped recess. [Effects of the Invention]

[0010] According to the present invention, by adopting the above-described configuration, it is possible to improve the sealing performance of the edge portion, which is a weak point of the seal, for a boot for a constant velocity joint having an irregularly shaped recess on the outer periphery. [Brief explanation of the drawings]

[0011] [Figure 1] 1A is a perspective cross-sectional view of a main part showing a fixing structure of a boot for a constant velocity joint according to the present invention, and FIG. 1B is an enlarged cross-sectional view of part I in FIG. 1A. [Figure 2] An explanatory diagram showing the first clamp member and the second clamp member in this invention, where (a) is a schematic cross-sectional view showing the contact portion with the edge portion of the second clamp member, and (b) is a schematic cross-sectional view showing the sliding portion of the first clamp member and the second clamp member. [Figure 3] 4 is a schematic cross-sectional view showing a state in which a boot is fixed by tightening a first clamping member in the present invention. FIG. [Figure 4] 10 is a schematic cross-sectional view showing another embodiment of the fixing structure for a boot for a constant velocity joint according to the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0013] As shown in Figure 1, a constant velocity joint case 1 (hereinafter referred to as joint case 1) is formed in an irregular shape with concave portions 2 at three circumferential locations on the outer periphery. This joint case 1 houses a tripod kit (not shown) which has multiple needle rollers assembled between three trunnions called tripods and a spherical roller, inside the joint case 1, in three pairs of roller grooves 3 which are parallel to the axial direction.

[0014] A rubber bellows-shaped boot 4 is fitted onto the outer periphery of the joint case 1 and fixed in place by tightening a clamp 10. The boot 4 has an irregularly shaped recess 5 formed therein that corresponds to the recessed portion 2 of the joint case 1.

[0015] 1 and 2, the clamp 10 comprises a strip-shaped first clamp member 11 that can be contracted and that surrounds the outer peripheral surface of the boot 4, and a second clamp member 12 that is disposed between the first clamp member 11 and the irregularly shaped recess 5 and has both ends that can slide circumferentially relative to the first clamp member 11. The first clamp member 11 is tightened in its contracted state by operating a lever (not shown) attached to the first clamp member 11.

[0016] In this case, as shown in Figure 2, the angle θ formed between a line L1 perpendicular to the tangent T1 of the edge portion 6 of the irregularly shaped recess 5 and a line L2 perpendicular to the tangent T2 of the portion of the second clamp member 12 that contacts the edge portion 6 is set to 45 degrees or less, and the circumferential length of the second clamp member 12 is formed to be greater than the circumferential length of the clamp contact surface of the irregularly shaped recess 5.

[0017] As described above, the reason why the angle θ is set to 45 degrees or less is that if the angle exceeds 45 degrees, the second clamping member 12 will deform in a crushing direction and will not be able to clamp. In addition, by forming the circumferential length of the second clamping member 12 to be equal to or greater than the circumferential length of the clamp contact surface of the irregularly shaped recessed portion 5, the second clamping member 12 generates a force that presses not only the edge portion 6 but the entire irregularly shaped recessed portion 5.

[0018] The procedure for fixing the boot 4 to the joint case 1 is as follows: first, the irregularly shaped recess 5 of the boot 4 is fitted to the concave portion 2 so as to match the shape of the joint case 1. After the boot 4 is fitted onto the joint case 1, the second clamp member 12 is placed between the irregularly shaped recess 5 and the first clamp member 11 is surrounded on the outer periphery of the boot 4. In this state, when the first clamp member 11 is contracted in diameter to tighten the boot 4, the first clamp member 11 generates a pressing force only in the radial direction, and as the first clamp member 11 contracts in diameter, both ends of the second clamp member 12 slide closer to each other, generating a force that presses not only the edge portion 6 but the entire irregularly shaped recess (see Figure 3).

[0019] 4 is a schematic cross-sectional view showing another embodiment of the constant velocity joint boot fixing structure according to the present invention. This embodiment is configured such that a pair of circular or elliptical third clamping members 13 are provided between the first clamping member 11 and the second clamping member 12. The third clamping members 13 are in contact with each other and have a resilient force that allows them to contact the first clamping member 11 and the second clamping member 12.

[0020] With this configuration, when the diameter of the first clamping member 11 is reduced to tighten the boot 4, both ends of the second clamping member 12 slide closer to each other as the diameter of the first clamping member 11 is reduced, and at the same time, the third clamping members 13 are pressed against each other and the third clamping member 13 is pressed against the first clamping member 11 and the second clamping member 12. This increases the force with which the second clamping member 12 presses not only the edge portion 6 but the entire irregularly shaped recessed portion 5, making it possible to further securely fasten the boot 4.

[0021] According to the fixing structure for the boot for a constant velocity joint of the above embodiment, when the first clamping member 11 is reduced in diameter to tighten the boot 4, the first clamping member 11 generates a pressing force only in the radial direction, and as the first clamping member 11 reduces in diameter, both ends of the second clamping member 12 slide closer to each other, generating a force that presses not only the edge portion 6 but the entire irregularly shaped recessed portion. Therefore, for boots 4 that have irregularly shaped recessed portions 5 on their outer periphery, the sealing performance of the edge portion 6, which is a weak point in the seal, can be improved, and leakage of grease from the joint case 1 can be prevented. [Explanation of symbols]

[0022] 1 Joint case (constant velocity joint case) 2 Concave part 4. Boots 5 Irregularly shaped recess 6 Edge 10 Clamp 11 First clamp member 12 second clamp member 13 Third clamp member

Claims

[Claim 1] A constant velocity joint boot fixing structure in which a constant velocity joint case having an irregular shape with a concave portion on its outer periphery and a boot fitted to the constant velocity joint case are fixed by fastening a clamp, the boot has a contoured recess corresponding to the concave surface, the clamp includes a first clamp member having a band shape that can be reduced in diameter and that surrounds the outer peripheral surface of the boot, and a second clamp member that is disposed between the first clamp member and the irregularly shaped recess and has both ends that can slide in a circumferential direction relative to the first clamp member; The angle formed by a line perpendicular to a tangent to the edge portion of the irregularly shaped recess and a line perpendicular to a tangent to a portion of the second clamp member that contacts the edge portion is set to 45 degrees or less, and the circumferential length of the second clamp member is formed to be equal to or greater than the circumferential length of the clamp contact surface of the irregularly shaped recess. A fixing structure for a boot for a constant velocity joint.

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