JP2011033065A - Boot for constant velocity joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent sinking of a thick-wall portion of a large diameter cylinder portion and to secure required sealability by uniformly fastening when fastening with a fastening member. <P>SOLUTION: In the boot including the large diameter cylinder part 11 having the thick-wall part 13 and a thin-wall part 14, a deep groove 18a is formed from the outer peripheral side toward the inner peripheral side in the thick-wall part 13 along the inner peripheral surface. A connecting part 20 for bridging fastening parts 19 is connected to the deep groove 18a. Projecting parts 21 projecting from the fastening parts 19 toward the deep groove 18a side are formed at positions away from both sides of the connecting part 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a boot that is covered with a constant velocity joint that is indispensable for a drive shaft joint of a front-wheel drive vehicle and prevents entry of water and dust into the joint portion of the constant velocity joint.

  The joint portion of the constant velocity joint is conventionally covered with a bellows-shaped boot, and smooth rotation at a large angle is maintained by preventing the intrusion of water and dust. The constant velocity joint boot includes a large-diameter large-diameter cylindrical portion that is held by a mating member such as a joint outer race, a small-diameter cylindrical portion that is smaller than the large-diameter cylindrical portion and is held by the shaft, and a large-diameter cylindrical portion. It is comprised from the substantially frustoconical bellows part which connects a small diameter cylinder part integrally. In use, the bellows portion is deformed in accordance with the change in the angle between the counterpart member and the shaft, so that the joint portion can be reliably sealed by the boot even when the operating angle is increased.

  By the way, the outer peripheral surface of a joint outer race or the like, which is a mating member, is not only circular in cross section but also non-circular in cross section. When fastened to such a counterpart member, the inner peripheral surface of the large-diameter cylindrical portion of the boot needs to have a non-circular shape corresponding to the outer peripheral surface of the counterpart member. However, since the large-diameter cylindrical portion needs to be fastened by a ring-shaped clamp (fastening member), the outer peripheral surface has a circular cross section. Therefore, it is necessary to form a thick part and a thin part in the large diameter cylindrical part.

  In recent years, a large-diameter cylindrical portion, a bellows portion, and a small-diameter cylindrical portion composed of a thick portion and a thin portion are integrally formed by injection blow molding. However, when a large-diameter cylindrical part composed of a thick part and a thin part is formed by injection molding, sink marks occur on the seal rib on the inner peripheral surface of the thick part after molding, and there is a gap between the mating member and the fastening member. In some cases, defective products may be generated that lead to grease leakage.

  In order to remedy this problem, Patent Document 1 is devised so that a groove is formed from the outer peripheral side to the inner peripheral side of the thick part so as not to cause a sink on the inner peripheral surface (seal rib) of the thick part. However, when tightened with a clamp, there was a problem that the groove was opened and the clamping force of the clamp was not transmitted to the inner peripheral surface of the thick part.

Special Table 2000-515827

  This invention is made in view of such a situation, and while preventing the sink of the inner peripheral surface (seal rib) of the thick part of a large diameter cylindrical part, the fastening force of a clamp (fastening member) is thick part. It is an object of the present invention to provide a boot that can be transmitted to the inner peripheral surface with higher accuracy and can secure the necessary sealing performance between the boot and the mating member.

The present invention provides a small-diameter cylindrical portion (10), a large-diameter cylindrical portion (11) that is coaxially disposed apart from the small-diameter cylindrical portion (10) and has a larger diameter than the small-diameter cylindrical portion (10), and the small-diameter It consists of a cylindrical part (10) and a substantially frustoconical bellows part (12) that integrally connects the large diameter cylindrical part (11), and a fastening member (2 from the outer peripheral side of the large diameter cylindrical part (11) ) Is a constant velocity joint boot (1) in which the large-diameter cylindrical portion (11) is fastened to the mating member (3) by reducing the diameter,
The large-diameter cylindrical portion (11) includes thin-walled portions (14) and thick-walled portions (13) projecting toward the inner peripheral side, which are alternately formed in the circumferential direction on the inner peripheral side. The inner peripheral surface of the thick wall portion (13) includes a ring-shaped seal rib (16) continuous in the circumferential direction,
The large-diameter cylindrical portion (11) has a solid fastening portion (19) that transmits a fastening force to the seal rib (16) when the ring-like fastening member (2) is fastened.
The thick portion (13) has a deep groove that opens to a fastening surface (19a) formed on the outer peripheral surface of the fastening portion (19) and extends along the inner peripheral surface of the thick portion (13) from the outer peripheral side. (18a) is formed,
In the center of the deep groove (18a), a connecting portion (20) for bridging between the fastening portions (19) is formed, spaced from the connecting portion (20) and from the fastening portion (19) to the deep groove (18a). A protruding portion (21) protruding to the side is formed.

In the large-diameter cylindrical portion 11 of the constant velocity joint boot 1, thick portions 13 and thin portions 14 are alternately arranged, and a deep groove 18a is formed in the thick portion 13 along the inner peripheral surface from the outer peripheral side. Has been. By disposing the connecting portion 20 at the center that is most likely to open among the deep grooves 18a, the opening of the deep grooves 18a is effectively prevented. Further, a protruding portion 21 that protrudes from the fastening portion 19 is formed at a position spaced apart from the connecting portion 20. As a result, the rigidity of the fastening portion 19 is increased, and the opening of the deep groove 18a when the clamp 2 is fastened is prevented, and the volume of the entire deep groove 18a is small, and the inner peripheral surface of the thick portion 13 can be prevented from sinking. Further, the solid fastening portion 19 is disposed immediately above the seal rib 16, and when the fastening portion 19 is fastened with the clamp 2, the deep groove 18 a does not open outward, and the fastening force of the clamp 2 is steadily transmitted through the fastening portion 19. Since it is transmitted to the seal rib 16, high sealing performance is exhibited.
As a preferred embodiment, since the protruding portions 21 are disposed as a pair opposed to the deep grooves 18 a on both sides of the connecting portion 20, the local sink of the seal rib 16 can be prevented and high sealing performance can be secured.
As a further preferred embodiment, the outer peripheral surfaces of the fastening portion 19 and the protruding portion 21 can be configured to be formed in the deep groove 18a rather than the fastening surface 19a. Thereby, the fastening force of the clamp 2 is transmitted only to the fastening part 19 and can be transmitted to the seal rib 16 with a uniform fastening force, and high sealing performance can be secured.

1 is a perspective view of a constant velocity joint boot according to an embodiment of the present invention. It is sectional drawing in the large diameter cylinder part of FIG. It is an outer peripheral side enlarged view of the thick part. It is sectional drawing of the XX line of FIG. It is sectional drawing of the YY line | wire of FIG.

  In order to further clarify the configuration and operation of the present invention described above, preferred embodiments of the present invention will be described below.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of a boot for a constant velocity joint of the present embodiment, FIG. 2 is a cross-sectional view of the boot viewed from the large-diameter cylindrical portion side, and FIG. 4 is a sectional view taken along line XX in FIG. 2, and FIG. 5 is a sectional view taken along line YY in FIG. The constant velocity joint boot 1 is formed from a thermoplastic elastomer material by injection blow molding. The constant velocity joint boot 1 has a small-diameter cylindrical portion 10, a large-diameter cylindrical portion 11 having a larger diameter than the small-diameter cylindrical portion 10, and a substantially truncated cone shape that integrally connects the small-diameter cylindrical portion 10 and the large-diameter cylindrical portion 11. It consists of a bellows part 12.

  In this constant velocity joint boot 1, a large-diameter cylindrical portion 11 is attached to a joint outer race 3 (a mating member), and is fastened by a clamp 2 (fastening member) from the outer periphery of the large-diameter cylindrical portion 11. The joint outer race 3 has a non-circular outer peripheral shape because a shaft having three rollers rotatably held at the tip is inserted. The outer periphery of the large-diameter cylindrical portion 11 has a perfectly circular cross section, but the inner peripheral surface has a non-circular deformed cross section corresponding to the outer peripheral surface of the joint outer race 3, and the thick portion 13 and the thin portion 14 are circumferential. Are alternately formed. As shown in FIG. 1, the thin-walled portion 14 includes a middle-walled portion 14a and a small-walled portion 14b.

  The large-diameter cylindrical portion 11 is formed by injection molding, and as shown in FIG. 4, a ring-shaped clamp positioning rib 15 protruding outward in the radial direction is formed on the end surface. The clamp 2 is disposed at the fastening portion 19 of the large diameter cylindrical portion 11, and the clamp positioning rib 15 prevents the clamp 2 from falling off. Three ring-shaped seal ribs 16 elastically contacting the joint outer race 3 are formed on the inner peripheral surfaces of the thick portion 13 and the thin portion 14 so as to extend in the circumferential direction and be parallel to each other on the entire circumference. At the time of fastening to the mating member, the seal rib 16 is pressed against the outer peripheral surface of the mating member, and high sealing performance is expressed.

  As shown in FIG. 4, between the thick portion 13 and the bellows portion 12, a connecting portion comprising a straight portion 22 a extending in the axial direction from the inner peripheral surface of the thick portion 13 and an inclined portion 22 b inclined radially outward. 22 are connected. Further, between the thick portion 13 and the inclined portion 22b, a thinned portion 23 is formed to prevent the seal rib 16 from sinking.

  A regulating portion 17 that protrudes radially inward from the small thickness portion 14b is formed inside the small thickness portion 14b of the large diameter cylindrical portion 11. The restricting portion 17 positions the joint outer race 3 inserted into the large-diameter cylindrical portion 11.

  On the other hand, the outer peripheral surface of the large-diameter cylindrical portion 11 is formed into a perfect circle shape, and among the three seal ribs 16, the fastening force of the clamp 2 is applied to the seal rib 16 from the outer peripheral surface to the inner peripheral surface of the two seal ribs 16 on both sides. A solid fastening portion 19 is formed for transmission to the. On the outer peripheral surface of the fastening portion 19, a fastening surface 19 a that is fastened by the clamp 2 is formed along the entire circumference together with the fastening portion 19. A ring groove 18 is formed at the center of the fastening portion 19 so as to open to the fastening surface 19a and make a round.

  Although the width of the ring groove 18 is constant over the entire circumference, as shown in FIGS. 1 and 4, the depth of the ring groove 18 is formed deep in the thick portion 13 and shallow in the thin portion 14, and its bottom surface is smooth. Draw a curve and continue. That is, the ring groove 18 of the thick portion 13 is a deep groove 18 a deeper than the groove of the thin portion 14. The width W of the deep groove 18a is 3 mm (see FIG. 4). Here, if the width L of the fastening portion 19 in the thick portion 13 is set to 0.2 <W / L <0.5, sink marks on the inner peripheral surface of the thick portion 13 are more effectively suppressed.

  FIG. 3 shows an enlarged view of the outer peripheral side of the thick portion 13. A deep groove 18a of the ring groove 18 is formed in the thick portion 13, and a connecting portion 20 is formed so as to bridge the fastening portion 19 in the center of the deep groove 18a. The wall thickness T of the connecting portion 20 is 1 mm. Here, the thickness T is set to 0.5 mm <T <2 mm so that the inner surface of the thick portion 13 is prevented from sinking and the deep groove 18a is not opened when the fastening surface 19a is fastened by the clamp 2. good.

A pair of opposed projecting portions 21 projecting from the fastening portion 19 toward the center of the deep groove 18a are formed at spaced positions on both sides of the connecting portion 20. The protrusion 21 has a protrusion height A = 1 mm, a width B = 3 mm, a surface area S (= A × B) set to 3 mm ² , and the height h of the protrusion 21 is 7 mm (FIG. 3, 5). Here, when the height of the fastening surface 19a from the bottom of the deep groove 18a is H and set to 0.8 <h / H <1 (see FIG. 5), the opening of the deep groove 18a when the clamp 2 is fastened is more effective. Can be prevented.

  The outer peripheral surfaces of the connecting portion 20 and the protruding portion 21 are formed one step deeper than the fastening surface 19a, and the clamp 2 does not act directly on the connecting portion 20 and the protruding portion 21 when tightened with the clamp 2. Yes.

As described above, according to the constant velocity joint boot 1 of the present embodiment, the deep groove 18a (ring groove 18) is formed in the thick portion 13, and when the clamp 2 is tightened, the deep groove 18a is most easily opened. The connecting portion 20 is arranged in the center to effectively prevent the deep groove 18a from opening. Further, a protruding portion 21 that protrudes from the fastening portion 19 is formed at a position spaced apart from the connecting portion 20. As a result, the rigidity of the fastening portion 19 is increased, the opening of the deep groove 18a when the clamp 2 is fastened is prevented, and the volume of the entire deep groove 18a is not reduced so much that the inner surface of the thick portion 13 can be prevented from sinking. Out of the three seal ribs 16, the outer two seal ribs 16 are arranged directly below the fastening portion 19 of the thick portion 13. As described above, when the fastening portion 19 is tightened with the clamp 2, the fastening force of the clamp 2 is steadily transmitted to the seal rib 16 through the fastening portion 19 without opening the deep groove 18a to the outside, so that high sealing performance is exhibited.
Further, in the deep grooves 18 a on both sides of the connecting portion 20, a pair of opposing protruding portions 21 that protrude from the fastening portion 19 are formed. Therefore, local sink of the seal rib 16 can be prevented and high sealing performance can be secured.
Further, the outer peripheral surfaces of the connecting portion 20 and the protruding portion 21 are formed one step deeper than the fastening surface 19a, so that the fastening force of the clamp 2 is not transmitted directly. For this reason, the fastening force of the clamp 2 does not act on the connecting portion 20 and the protruding portion 21 but is transmitted only to the fastening portion 19, so that a uniform fastening force can be transmitted to the seal rib 16, and high sealing performance can be secured.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used for a constant velocity joint boot that prevents water and dust from entering the joint portion of the constant velocity joint.

1 Constant velocity joint boot 2 Clamp (fastening member)
3 Joint outer race (mating member)
6 Shaft 10 Small diameter cylindrical part 11 Large diameter cylindrical part 12 Bellows part 13 Thick part 14 Thin part 14a Middle part 14b Small part 15 Clamp positioning rib 16 Seal rib 17 Restriction part 18 Ring groove 18a Deep groove 19 Fastening part 19a Fastening surface 20 Connecting part 21 Protruding part 22 Connecting part 22a Straight part 22b Inclined part 23 Meat extraction part

Claims (3)

A small-diameter cylindrical portion (10), a large-diameter cylindrical portion (11) that is coaxially disposed apart from the small-diameter cylindrical portion (10) and has a larger diameter than the small-diameter cylindrical portion (10), and the small-diameter cylindrical portion (10 ) And a substantially frustoconical bellows portion (12) integrally connecting the large-diameter cylindrical portion (11), and the fastening member (2) is reduced in diameter from the outer peripheral side of the large-diameter cylindrical portion (11). A constant velocity joint boot (1) in which the large-diameter cylindrical portion (11) is fastened to the counterpart member (3),
The large-diameter cylindrical portion (11) includes thin-walled portions (14) and thick-walled portions (13) projecting toward the inner peripheral side, which are alternately formed in the circumferential direction on the inner peripheral side. The inner peripheral surface of the thick wall portion (13) includes a ring-shaped seal rib (16) continuous in the circumferential direction,
The large-diameter cylindrical portion (11) has a solid fastening portion (19) that transmits a fastening force to the seal rib (16) when the ring-like fastening member (2) is fastened.
The thick portion (13) has a deep groove that opens to a fastening surface (19a) formed on the outer peripheral surface of the fastening portion (19) and extends along the inner peripheral surface of the thick portion (13) from the outer peripheral side. (18a) is formed,
In the center of the deep groove (18a), a connecting portion (20) for bridging between the fastening portions (19) is formed, spaced from the connecting portion (20) and from the fastening portion (19) to the deep groove (18a). A boot for a constant velocity joint, characterized in that a protruding portion (21) protruding to the side is formed.   The protrusions (21) are arranged in a pair so as to face the deep grooves (18a) on both sides of the connecting part (20) from the fastening part (19) toward the center of the deep groove (18a). The boot for a constant velocity joint according to claim 1.   The constant velocity according to claim 2, wherein outer peripheral surfaces of the connecting portion (19) and the protruding portion (21) are formed in the deep groove (18a) rather than the fastening surface (19a). Joint boots.