JP2007211928A - Attaching structure of boot for constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an attaching structure of a boot for a constant velocity universal joint avoiding interference of part of the boot with a lug of a booth band even when the joint has a large operation angle. <P>SOLUTION: The boot is arranged between an outer periphery of an outer joint member and an outer periphery of an intermediate portion of a shaft in the constant velocity universal joint in which a torque transmission member is received between the outer joint member and an inner joint member and the shaft connected to the inner joint member extends outside the joint. The boot comprises a cylindrical large diameter portion 1a fixed to the outer peripheral surface of the outer joint member 2 by the boot band 3, a cylindrical small diameter portion fixed to an outer peripheral surface of the shaft, a bellows 1d interconnecting the large and small diameter portions, and a shoulder 1c disposed between the large diameter portion and the bellows and covering an outer peripheral surface on an open end side of the outer joint member, wherein a low sectional annular member, which has a height of the same level with a boot band body other than the lug 3a serving as a caulking portion of the boot band 3, is fitted over an outer peripheral surface of the shoulder 1c. The annular member is formed of, for instance, plural rows or a single row of O-rings 4 or a thin-walled cylinder 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a boot mounting structure that covers a constant velocity universal joint used for a drive shaft of an automobile, and in particular, adjacent to the boot band with respect to a boot band that fixes a large end of a boot to a joint outer ring. The present invention relates to a mounting structure for a constant velocity universal joint boot in which the shoulder portion and the bellows portion of the boot large end portion do not interfere even at a high operating angle of the joint.

  The constant velocity universal joint is provided with a bellows-like boot for the purpose of preventing leakage of grease sealed in the joint and preventing foreign matter from entering the joint. Both ends of the boot are respectively fitted to an outer ring and a shaft which are outer joint members of a constant velocity universal joint, and both ends of the boot are fastened by a boot band and fixed to each other. This constant velocity universal joint boot is generally classified into a rubber boot made of a rubber material such as chloroprene rubber (CR) and a resin boot made of a resin material such as thermoplastic elastomer (TPE).

  In order to fit and fix these boots to the outer ring which is the outer joint member of the constant velocity universal joint, the caulking described in Patent Document 1 (Japanese Patent No. 2538554 (Japanese Patent Laid-Open No. Sho 61-13007)) and the like Many types of boot bands are used. This type of boot band applies a binding force to the outer ring or shaft by caulking a portion called an “ear” and plastically deforming it. The ears of the boot band protrude on the outer circumference of the band.

Conventionally, in a constant velocity universal joint using such a caulking type boot band, as shown in FIG. 3A, the distance (L1) between the outer ring end surface 2b and the ear 3a of the boot band 3 and the boot 1 The distance (L2) to the bellows start part 1b was relatively short. Therefore, as shown in FIG. 3B, when the operating angle of the shaft S of the constant velocity universal joint increases, a part of the bellows portion 1d and the shoulder portion 1c interfere with the ear 3a of the boot band 3 on the large diameter portion 1a side. was there. When such interference occurs, the boot 1 may be damaged, or the boot band 3 may be pushed and displaced in the direction of the arrow in FIG. Therefore, in order to prevent interference between the boot 1 and the ear 3a of the boot band 3, various structures disclosed in Patent Documents 2 to 5 have been proposed.
Japanese Patent No. 2538554 JP-A-7-229563 JP 2002-98238 A JP 2000-205291 A JP 2000-9153 A

In Patent Document 2, an interference member called a rib is provided between the ears of the boot band and the bellows part of the boot to prevent the interference between the bellows part and the ears of the boot band. In Patent Document 3, a plurality of ribs are provided to further prevent interference between the ears of the boot band and the bellows portion of the boot at a high angle.
However, although these structures can prevent the bellows from being damaged, it is inevitable that the ears of the boot band come into contact with the nearest rib. For this reason, the force which a rib pushes an ear to an axial direction generate | occur | produces, and a boot band may shift | deviate.
In Patent Document 4, an interference member called a partition wall is provided between the ears of the boot band and the bellows part so that the bellows part does not directly interfere with the ears of the boot band. However, although this structure can prevent damage to the bellows part, a force that pushes the boot band in the axial direction is generated when the ear is indirectly pressed, and the boot band may also be displaced.
In Patent Document 5, a spacer portion is provided between the ears of the boot band and the bellows portion so that the bellows portion does not interfere with the boot band crimping portion. However, when the joint operating angle is large, for example, 45 ° or more, the amount of deformation of the bellows increases further, so even this structure completely prevents the interference between the bootband ears and the bellows, or the displacement of the bootband. Not enough to
An object of the present invention is to provide a boot for a constant velocity universal joint in which a part of the boot does not interfere with the ear portion of the boot band even when the joint has a high operating angle exceeding 45 °.

In order to solve the above problems, the invention according to claim 1 is configured such that a torque transmission member is accommodated between an outer joint member and an inner joint member, and a shaft connected to the inner joint member extends outside the joint. The constant velocity universal joint is a boot disposed between the outer periphery of the outer joint member and the outer periphery of the intermediate portion of the shaft, and is a cylindrical large member fixed to the outer peripheral surface of the outer joint member with a boot band. A diameter portion, a cylindrical small diameter portion fixed to the outer peripheral surface of the shaft, a bellows portion connecting the large diameter portion and the small diameter portion, and an opening of the outer joint member between the large diameter portion and the bellows portion A low cross-sectional annular shape having a shoulder portion covering the end-side outer peripheral surface with a predetermined length, and having a height similar to that of a boot band body other than an ear portion serving as a caulking portion of the boot band on the outer peripheral surface of the shoulder portion The member is fitted. Even if the joint shaft has a high operating angle of 45 ° or more, for example, the bellows start portion of the boot is originally the shoulder by forming the shoulder portion with a predetermined length and fitting an annular member with a low profile to the outer peripheral surface thereof. It is separated from the boot band ear by the length of the part, and the shoulder is lifted and bent deformation is prevented by the low-section annular member, so that the bent part can be reliably prevented from protruding to the boot band side. Can do. Of course, since the low cross-section annular member has a low cross section similar to the boot band body, there is no interference with the bellows portion.
The invention of claim 2 is characterized in that, in the invention of claim 1, the low cross-section annular member is constituted by a double row or single row O-ring. The invention of claim 3 is characterized in that, in the invention of claim 1, the low-section annular member is formed of a thin cylindrical body.
Both the O-ring and the thin-walled cylinder can surely prevent the shoulder from being lifted and bent, and the cross-section is as low as that of the boot band body, so that there is no interference with the bellows.

  As described above, since the present invention has a mounting structure in which a low-section annular member is fitted to the outer peripheral surface of the shoulder having a predetermined length between the large-diameter portion of the boot and the bellows portion, the bellows start portion of the boot has the predetermined length. The band can be isolated from the ears of the band, and the shoulder lift is prevented by a low-section annular member to prevent interference between the shoulders of the boot and the ears of the bootband, thereby shifting the bootband in the axial direction. Can be prevented.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 shows a cross section of a large diameter portion of a boot 1 for a constant velocity universal joint according to an embodiment of the present invention. The overall shape of the boot 1 is substantially the same as the conventional one, and is fixed to the outer peripheral surface of the outer joint member (outer ring 2) of the constant velocity universal joint and the outer peripheral surface of the constant velocity universal joint. The boot 1 is composed of a small diameter part (not shown) and a bellows part (not shown) connecting the large diameter part and the small diameter part. The bellows part is composed of two to seven mountain parts and valleys between the mountain parts. The boot 1 is formed from a rubber material such as chloroprene rubber (CR). The material of the boot 1 is not limited to a rubber material, and may be molded from a resin material such as a thermoplastic elastomer (TPE).

  A large-diameter portion 1 a that is an outer ring attachment portion of the boot 1 is fitted into the innermost part of a shallow step portion 2 a formed on the outer peripheral surface of the outer ring 2. The boot band 3 is fixed to the outer peripheral surface of the large diameter portion 1a. A shoulder 1c having a predetermined length (L2) is formed in a straight shape adjacent to the large diameter portion 1a. This shoulder 1c extends horizontally (in parallel with the outer peripheral surface of the outer ring) in contact with the outer ring 2 from the large diameter part 1a of the boot 1 to the bellows start part 1b. The boot 1 is radially reduced from the bellows start portion 1b to form a side wall of the first bellows portion.

  In the conventional boot 1, as described above, the distance (L1) between the outer ring end face 2b and the ear 3a of the boot band 3 and the dimension (L2) to the bellows start portion 1b of the boot 1 were relatively short. In the present invention, the dimension (L1) is set larger than the conventional one. Thereby, the dimension (L2) of the shoulder part 1c from the ear | edge 3a of the boot band 3 to the boot bellows start part 1b is longer than before. Furthermore, according to the present invention, a groove is provided in each of the large-diameter portion 1a and the shoulder portion 1c of the boot, and the boot band 3 is fitted into the groove portion of the large-diameter portion 1a as usual. Partition ribs 1e are erected on both sides of the groove. A double row O-ring 4 is attached and fixed to the groove of the shoulder 1c. The number of O-rings 4 may be set to an appropriate number that can secure the strength that prevents the shoulder 1c from floating, but is preferably about 2 to 5 in consideration of the balance between function and efficiency. The O-ring 4 can be arranged in a single row even if it is not double-row as long as it is thick enough to satisfy a low cross section. Further, the cross section of the O-ring 4 is not limited to a circle but may be a polygon, for example.

  For the O-ring 4, for example, a thermosetting resin, a thermoplastic resin, a heat shrinkable tube, rubber, or the like can be used. As the thermosetting resin, epoxy resin, phenol resin, polyimide resin, urethane resin, polyurea resin, acrylic urethane resin, fluorine resin, unsaturated polyester resin, vinyl ester resin, acrylic resin, silicone resin, silane, or the like can be applied. As the thermoplastic resin, polystyrene, polypropylene, polyethylene, ABS, acrylic resin, polyacetal, polyamide, polycarbonate, PBT, PET, PEEK, PPS, or the like can be applied. Olefin-based, silicone-based, and fluorine-based resins and elastomers can be applied to the heat-shrinkable tube. As the thermoplastic elastomer, ester-based, olefin-based, urethane-based, amide-based, styrene-based, and the like can be applied. As the rubber, CR, EPDM, NBR, SBR or the like can be applied.

  Thus, any material can be selected, but it is preferably harder than the boot material. For example, the resin preferably has a type D durometer hardness of 50 or more according to JIS K6253, and the rubber has a type A durometer hardness of 80 or more according to JIS K6253.

  By fixing the shoulder portion 1c with the O-ring 4, the shoulder portion 1c is hardly lifted even when the operating angle of the constant velocity universal joint is increased. This and the effect of increasing the dimension (L2) of the shoulder 1c described above can prevent the shoulder 1c or the bellows start part 1b from interfering with the ear 3a of the boot band 3.

  The O-ring 4 described above may be replaced with a thin-walled cylinder 5 as shown in FIG. Similarly to the O-ring 4, the thin-walled cylinder 5 also exhibits the effect of preventing the shoulder 1c from being lifted. As the material of the thin-walled cylinder 5, any material can be selected similarly to the O-ring.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the technical idea included in the claims.

  The constant velocity universal joint boot of the present invention is a type that can take a large operating angle of 45 ° or more, for example, a fixed type constant velocity universal joint using a ball such as a Zepper type or a barfield type, or an outer joint. Applicable to boots used for all constant velocity universal joints such as sliding type constant velocity universal joints such as double offset type, tripod type, cross groove type, etc. .

The large diameter section sectional view showing the attachment part structure of the boot for constant velocity universal joints concerning the embodiment of the present invention. The large diameter part sectional view which shows the attachment part structure of the boot for constant velocity universal joints which concerns on the deformation | transformation embodiment of this invention. It is sectional drawing of the large diameter part of the conventional boot for constant velocity universal joints, Comprising: (A) is a shaft operating angle 0 degree, (B) is sectional drawing in the case of a shaft operating angle 45 degrees.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Boot 1a Large diameter part 1b Bellows start part 1c Shoulder part 1d Bellows part 1e Partition rib 2 Outer ring 2a Step part 2b Outer ring end surface 3 Boot band 3a Ear 4 O-ring 5 Thin-walled cylinder

Claims (3)

  A torque transmission member is accommodated between the outer joint member and the inner joint member, and a shaft connected to the inner joint member extends outside the joint. A boot mounting structure disposed between the outer periphery of the intermediate portion of the shaft and a cylindrical large-diameter portion fixed to the outer peripheral surface of the outer joint member by a boot band, fixed to the outer peripheral surface of the shaft A cylindrical small-diameter portion, a bellows portion connecting the large-diameter portion and the small-diameter portion, and a shoulder between the large-diameter portion and the bellows portion and covering the outer circumferential surface of the outer joint member with a predetermined length A low-section annular member having a height similar to that of the boot band main body other than the ear part serving as a caulking part of the boot band is fitted to the outer peripheral surface of the shoulder part of the boot having a portion. A mounting structure for a boot for a constant velocity universal joint.   The mounting structure of the boot for a constant velocity universal joint according to claim 1, wherein the low-section annular member is constituted by a double row or a single row O-ring.   2. The mounting structure for a constant velocity universal joint boot according to claim 1, wherein the low-section annular member is formed of a thin cylindrical body.

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