JPH0755002A - Fixing structure of boot - Google Patents

Abstract

PURPOSE:To securely prevent the circumferential turning between the fixing part of a boot and a constant joint, and also to maintain a high sealing strength by making the outside diameter of the part on which the boot is to be fitted larger than the inside diameter of the fixing part of the boot, and by forming a cutout part in the outer circumference thereof. CONSTITUTION:In the structure in which a boot made of a thermoplastic elastomer and having seal-fixing parts 3, 4 at both ends of a bellows part 2 is fitted to a constant-speed joint 9, a thick-thickness peripheral part 8 is formed on the outer end of the fixing part 3 at least on one side, and the outside diameter of the part on which the thick-thickness part 8 of the fixing part 3 of the outer ring 10 of the constant-speed joint is fitted is made larger than the inside diameter of the thick-thickness part 8 so as to be a large-diameter part 12, and also a cutout part 13 is formed on the outer circumferential surface thereof. Thereby, when the outer ring 10 of the constant-speed joint 9 is inserted into the fixing part 3, the thick-thickness peripheral part 8 is fitted to the large-diameter part 12 so as to be pressedly brought into contact therewith in an expanded state, so that the circumferential turning between the constant-speed joint 9 and the boot 1 can be securely prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boot fixing structure for mounting boots for constant velocity joints of automobiles and various other equipments on a member to be mounted.

[0002]

2. Description of the Related Art As a boot for a constant velocity joint of an automobile, a boot made of a thermoplastic elastomer and provided with fixing portions for tightly sealing the outer ring and the shaft of the constant velocity joint at both ends of the bellows portion, etc. The boot fixed to the outer ring and the shaft of the quick joint is, for example, as disclosed in Japanese Utility Model No.
The thing etc. which are described in the 121 publication are known.

Most of the boots for constant velocity joints of automobiles of this type are composed of a thermoplastic elastomer because they are excellent in heat resistance and durability and easy to mold.
Thermoplastic elastomers generally have higher rigidity than rubber and thus have poor adhesion to metal, and their fixed parts are easily slipped off due to slippage with the outer ring or shaft surface of the joint made of metal, Moreover, it is said that the seal strength is poor. Also, thermoplastic elastomers soften at high temperatures,
Since it cures at a low temperature, the fixing strength is lowered and the sealing strength is lowered in any state. In particular, when a rotational force acts on the boot under a low temperature condition, the fixing portion is likely to slip in the circumferential direction of the mounted member, and the boot is twisted and deformed, which accelerates deterioration and damage.

[0004]

By the way, in the one disclosed in Japanese Utility Model Laid-Open No. 61-181121, a large number of irregularities are axially formed on the surface of the mounted member to fix the boot. Since the inner peripheral surface of the portion is fixed by meshing with a large number of irregularities, it is possible to prevent the boot from rotating in the axial direction. However, in the configuration in which the mounted member is formed with the unevenness in the axial direction as described above,
Since the unevenness in the axial direction also serves as a guide passage in the axial direction between the mounted member and the fixing portion, there is a possibility that the sealing property of the fixing portion of the boot may be impaired.

The present invention is intended to solve this problem, and it is possible to reliably prevent circumferential rotation between the fixed portion of the boot and the mounted member and to provide a boot having an extremely high seal strength. It is intended to provide a fixed structure of

[0006]

The present invention has the following constitution to achieve the above object. That is, the fixing structure of the boot according to the present invention, in the fixing structure for mounting the boot made of a thermoplastic elastomer to the mounted member having a fixing portion for tightly sealing the mounted member at both ends of the bellows portion, A thick edge portion is formed on the outer end of at least one of the fixed portions, and a portion of the attached member where the thick edge portion of the fixed portion fits is a large diameter portion having a diameter larger than that of the thick edge portion. The notch is formed on the outer peripheral surface of the large diameter portion.

In the above structure according to the present invention, it is preferable that a plurality of cutouts are formed in the large diameter portion of the mounted member in the circumferential direction.

[0008]

In the fixing portion of the boot according to the present invention, the thick edge portion is formed at the outer end of the fixing portion, and the portion to which the thick edge portion of the fixing portion of the mounted member fits is the thick edge portion. Since the large diameter part has a larger diameter and the notch is formed on the outer peripheral surface of the large diameter part, when the fixing part is inserted into the mounted member, the thick edge part has a larger diameter than that. It is crimped into the diameter part and expanded. For this reason, the inner surface portion corresponding to the cutout portion of the thick edge portion bites into the cutout portion, and the circumferential rotation of the fixed portion with respect to the mounted member is reliably prevented. Further, since there is no groove in the axial direction between the mounted member and the fixing portion, a high sealing strength can be obtained in the fixing portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show a fixing structure of a boot for a constant velocity joint of an automobile. In FIG. 1, reference numeral 1 denotes a boot. The boot 1 is formed by blow molding or injection molding of a single thermoplastic elastomer such as polyester, polyurethane, polyamide, polyolefin, or soft vinyl chloride, or a blend thereof. Alternatively, it is formed into a single layer or a multilayer by injection blow molding. The boot 1 is formed by integrally forming a large cylindrical fixing portion 3 at one end of a bellows portion 2 and a small cylindrical fixing portion 4 at the other end. An annular recess 5 for mounting a flat belt-shaped fastener (not shown) is formed on the outer peripheral surface of the fixing portion 3. The thermoplastic elastomer forming the boot 1 has a tensile elastic modulus (JIS K6301) of 100 to 20.
It is an elastic material having a relatively large strength of 00 Kg / cm ² , and is a relatively soft material having a Shore D hardness of 55 or less.

As shown in detail in FIG. 2, the annular recessed portion 5 of the fixing portion 3 is formed with an annular recessed groove portion 6 at a substantially central portion in the axial direction thereof, and the annular recessed portion corresponding to the annular recessed groove portion 6. On the inner peripheral surface of 5, an annular protruding portion 7 is formed which protrudes inward. A thick edge portion 8 having the same inner diameter as the inner diameter of the annular recess 5 is formed at the outer end of the fixing portion 3. The thick-walled edge portion 8 is thickened on the outer peripheral side so as to form a rising portion on the outer end side of the annular recessed portion 5. Note that, as shown in FIG. 1, the fixing portion 4 has the same structure as the fixing portion 3, but the description thereof will be omitted.

The boot 1 is attached to a constant velocity joint 9 as shown in FIG. The fixing portion 3 of the boot 1 is fixed to the outer ring 10 and the fixing portion 4 of the boot 1 is fixed to the shaft 11 by tightening fasteners (not shown). 2 and 3
As shown in detail in FIG. 1, the outer ring 10 has a large diameter portion 12 to which the thick edge portion 8 of the fixing portion 3 fits, and the large diameter portion 12 is provided with a plurality of cutout portions 13. Has been. Outer ring 1
At 0, a ring groove 14 into which the annular protrusion 7 is fitted is provided. The inner diameter d of the fixed portion 3 is formed to be the same as or slightly smaller than the outer diameter D of the outer ring 10, and the large diameter portion 12 has an outer diameter with which the thick edge portion 8 is fitted in a crimped state in the expanded state. is doing.
The depth of the notch 13 is the same as or slightly higher than the outer diameter D of the outer ring 10. Although the cutouts 13 are formed at equal angles in the circumferential direction of the large diameter portion 12 of the outer ring 10, the present invention is not limited thereto.

As shown in FIG. 2, when the fixing portion 3 is inserted from the end portion of the outer ring 10, the thick edge portion 8 of the fixing portion 3 is fitted in the large diameter portion 12 of the outer ring 10 in the expanded state. As shown in FIG. 3, a portion corresponding to the cutout portion 13 is deformed by the pressure bonding force on the inner surface side and engages with the cutout portion 13 in a state of biting. Then, in this state, in the fixing portion 3, the annular protruding portion 7 is fitted into the ring concave groove 14, and the annular concave portion 5 is tightened by the fastener, so that the fixing portion 3 has the annular protruding portion 7 in the ring concave portion. It is firmly fixed while being fitted in the groove 14. Since the excessive deformation due to the pressure bonding of the annular protruding portion 7 is absorbed by the annular concave groove portion 6, the fixing portion 3 is tightly and firmly fixed to the outer ring 10 and the thick edge portion 8 with respect to the notch portion 8 is formed. Due to the engagement of the inner surface of the, the rotation of the fixing portion 3 in the circumferential direction is reliably prevented. Since the thermoplastic elastomer constituting the boot 1 is a relatively soft material having a Shore D hardness of 55 or less,
By fitting the thick-walled edge portion 8 into the large-diameter portion 12 of the outer ring 10 in a diameter-expanded state, a portion of the inner surface corresponding to the notch portion 13 is surely bite into the notch portion 13, and the circumferential direction The engagement state that prevents the rotation of is good. The small-diameter fixed portion 4 is also fixed to the shaft 11 of the constant velocity joint 9 in the same manner, and the same effect can be obtained between the fixed portion 4 and the shaft 11.

[0013]

According to the present invention, it is possible to reliably prevent circumferential rotation between the fixed portion of the boot and the mounted member, and
It is possible to obtain a boot fixing structure having extremely high sealing strength.

[Brief description of drawings]

FIG. 1 is an overall front view showing a boot according to an embodiment of the present invention with a part thereof cut away.

FIG. 2 is a cutaway front view showing a part of the boot shown in FIG. 1 in an enlarged manner.

FIG. 3 is a schematic vertical cross-sectional view showing a mounting manner of an outer ring and a fixed portion of a constant velocity joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 boot 2 bellows part 3, 4 fixing part 5 annular concave part 8 thick edge part 9 constant velocity joint 10 outer ring 12 large diameter part 13 notch part

Claims (1)

[Claims] 1. A fixing structure for mounting a boot made of a thermoplastic elastomer having a bellows portion and fixing portions at both ends of the bellows portion for tightly sealing the member to be attached to the member to be attached. A thick edge portion is formed at an end, and a portion where the thick edge portion of the fixed portion of the mounted member fits is a large diameter portion having a diameter larger than the thick edge portion, and an outer periphery of the large diameter portion. A fixing structure for a boot, characterized in that a notch is formed on the surface.