JP2008045696A - Boots fixing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boots fixing structure in which the need for using an omega band and a turnback band is eliminated, a clearance between itself and peripheral portions is sufficiently secured, and besides a reduction in its property due to a buffering operation against a foreign material is avoided. <P>SOLUTION: There is provided the boots fixing structure in which a large diameter part 45a of a boots 45 is mounted on an outer joint member of a constant velocity joint, and besides a small diameter-part 45b of the boots 45 is mounted on a shaft 40 fitted into an inner joint member of the constant velocity joint. A circumferential depressed groove 54 is formed in an opening end surface 53 of the outer joint member. Then, the large diameter part 45a of the boots 45 and a ring body 55 are press-fitted in the circumferential depressed groove 54. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a boot fixing structure, and more particularly to a boot fixing structure mounted on a constant velocity universal joint.

  For example, a constant velocity universal joint is used as means for transmitting a rotational force from an automobile engine to wheels at a constant speed. This constant velocity universal joint has a structure in which two axes of a driving side and a driven side are connected and rotational torque can be transmitted at a constant speed even if the two axes take an operating angle. Generally, as the above-described constant velocity universal joint, a bar field type (BJ) and an undercut free type (UJ) are widely known.

  As shown in FIG. 7, the UJ type constant velocity universal joint includes an outer ring 3 as an outer joint member in which a plurality of track grooves 2 are formed on the inner diameter surface 1 along the axial direction at equal intervals in the circumferential direction, An inner ring 6 as an inner joint member in which a plurality of track grooves 5 paired with the track grooves 2 of the outer ring 3 are formed on the radial surface 4 at equal intervals in the circumferential direction, and the track grooves 2 of the outer ring 3 A plurality of balls 7 that are interposed between the track grooves 5 of the inner ring 6 and transmit torque, and a cage that is interposed between the inner diameter surface 1 of the outer ring 3 and the outer diameter surface 4 of the inner ring 6 and holds the balls 7. 8 and.

  A shaft 10 is fitted into the inner ring 6. That is, the spline portion 11 is formed on the inner diameter surface of the center hole of the inner ring 6, and the spline portion 9 of the shaft 10 is fitted to the spline portion 11. Note that a circumferential groove 12 is formed in the spline portion 9 of the shaft 10, and a retaining ring 13 for retaining the shaft is mounted in the circumferential groove 12.

  A boot 15 is attached to the opening of the outer ring 3. The boot 15 includes a large diameter portion 15a, a small diameter portion 15b, and a bellows portion 15c between the large diameter portion 15a and the small diameter portion 15b. The large diameter portion 15 a is fitted to the outer diameter surface on the opening side of the outer ring 3, and the small diameter portion 15 b is fitted to the boot mounting portion 16 of the shaft 10.

  In this case, a circumferential groove 17 is formed on the outer peripheral surface of the large-diameter portion 15a, and a boot band 18 is fastened to the circumferential groove 17 so that the large-diameter portion 15a and the outer ring 3 are integrated. Further, a concave groove 19 is formed in the boot mounting portion 16 of the shaft, and a small diameter portion 15 b is fitted in the circumferential concave groove 19. A circumferential groove 20 is formed on the outer peripheral surface of the small diameter portion 15b, and the boot band 18 is fastened to the circumferential groove 20 so that the small diameter portion 15b and the shaft 10 are integrated.

  That is, the boot 15 is attached to prevent leakage of a lubricant such as grease enclosed in the joint and to prevent foreign matter from entering the joint. The boot includes a rubber boot made of a rubber material such as chloroprene rubber (CR) and a resin boot made of a thermoplastic elastomer.

  Resin boots have higher material hardness and less elasticity than rubber boots. For this reason, in order to ensure sufficient fixing strength and sealing performance, a caulking type band (omega band 14) having an omega (Ω) -shaped clamp portion that can obtain a larger tightening force in the boot band 18 (patented) Document 1) is often used.

  As shown in FIG. 8, the omega band 14 is rolled into a ring shape, and the hook portion 21 is locked to the locking hole 22 in a state where both ends thereof are overlapped with each other on the inner side and the outer side. It is fitted on the outer ring. A projecting portion 23 that bulges in the outer diameter direction is formed on the outer peripheral surface, and the formed annular portion 24 is formed by applying a pressing force in the direction of the arrow to the legs 23a and 23a of the projecting portion 23. The diameter is reduced and the mounted portion is tightened.

Further, the boot band 18 may be a folded type as shown in FIG. In this folded type, the band-shaped band main body 25 is bent into a ring shape and joined in a state where both ends thereof are overlapped. A band member 27 is attached to the overlapping portion (coupling portion) 26. Then, the band member 27 is swung (turned back) as indicated by an arrow A, and the band member 27 is fixed to the stopper 29. In this case, the band member 27 is folded back to reduce the diameter of the ring portion 28 constituted by the band main body 25 and tighten the mounted portion.
Japanese Patent Laid-Open No. Sho 63-172085

However, if the omega band 14 is used, as shown in FIG. 7, the overhanging portion 23 protrudes to the outer diameter side, and the outer diameter surface of the overhanging portion 23 becomes the outermost diameter. For this reason, there is a concern about the clearance with the peripheral part. That is, it is necessary to secure a sufficient clearance between the overhanging portion 23 and the peripheral portion, which causes a problem in assembling. Further, when a foreign object hits the overhanging portion 23 during traveling or the like, the band tightening force may be reduced and the sealing performance may be impaired. That is, there is a concern about deterioration of sealing performance.

  Further, even in the folded type, the folded portion and the stopper 29 protrude to the outer diameter side, and the outer diameter surface of the stopper 29 becomes the outermost diameter. For this reason, even in this case, there is a concern about the clearance between the stopper 29 and the peripheral portion, and when the foreign object hits the stopper 29, the stopper 29 comes off from the band member 27, or the band tightening force decreases. As a result, the sealing performance may be impaired.

  In view of the above problems, the present invention eliminates the need to use an omega band or a folded-type band, can sufficiently secure a clearance with a peripheral portion, and avoids a concern about a decrease in sealing performance due to buffering of foreign matter. A boot fixing structure is provided.

  In the boot fixing structure of the present invention, the large-diameter portion of the boot is mounted on the outer joint member of the constant velocity universal joint, and the small-diameter portion of the boot is mounted on the shaft fitted in the inner joint member of the constant velocity universal joint. In the boot fixing structure, a circumferential groove is formed on the opening end face of the outer joint member, and the large-diameter portion of the boot and the ring body are press-fitted into the circumferential groove.

  According to the boot fixing structure of the present invention, the large-diameter portion of the boot is fixed to the outer joint member by press-fitting the large-diameter portion of the boot and the ring body into the circumferential groove on the opening end surface of the outer joint member. Can do. For this reason, the large diameter portion of the boot does not protrude beyond the outer diameter surface of the outer joint member.

  Moreover, it is preferable to perform the crimping process which reduces the opening dimension of the opening part of a circumferential groove on the opening edge part of an outer joint member. By caulking in this manner, the opening size of the opening is reduced, and the tightening force for the large-diameter portion of the boot is increased on the opening side of the circumferential groove.

  The ring body can be provided with a tapered surface that increases the radial thickness of the ring body from the depth of the groove toward the groove opening side. Moreover, the taper surface which reduces the radial direction clearance dimension of a circumferential groove | channel from a groove | channel back toward a groove opening side can be provided in a circumferential groove | channel. These also increase the tightening force for the large-diameter portion of the boot on the opening side of the circumferential groove.

  An anti-slip portion can be provided on the ring body or the like. Thereby, during rotation of the constant velocity universal joint, the large-diameter portion of the boot does not shift in the circumferential direction, and the large-diameter portion can be prevented from coming off from the circumferential groove.

  The ring body can be provided with a convex portion that bites into the large diameter portion of the boot. Thereby, the clamping force with respect to the large diameter part of boots increases. Further, a protrusion for restricting the axial displacement of the boot can be provided on the large diameter portion of the boot. Accordingly, it is possible to prevent the large-diameter portion from coming off from the circumferential groove of the large-diameter portion of the boot.

  In the boot fixing structure of the present invention, since the large diameter portion of the boot does not protrude from the outer diameter surface of the outer joint member, the clearance with the peripheral component can be determined by the outer diameter surface of the outer joint member. And the assemblability of the constant velocity universal joint is improved. Further, it is no longer necessary to use a boot band as in the prior art, and there is no loosening of the boot band due to collision of foreign matter with the boot band. For this reason, the boot exhibits a stable sealing effect over a long period of time.

  By caulking the opening end of the outer joint member, the opening size of the opening is reduced, the tightening force against the large diameter part of the boot is increased, and the radial thickness of the ring body is set on the ring body. A taper surface that increases from the groove opening side toward the groove opening side, a taper surface that decreases the radial clearance dimension of the circumferential groove from the groove back toward the groove opening side, The tightening force for the large-diameter portion of the boot is also increased by providing the ring body with a convex portion that bites into the large-diameter portion of the boot. As described above, when the tightening force for the large-diameter portion of the boot is increased, the fixing force of the boot to the outer joint member is increased, and the boot exhibits a stable sealing effect.

  By providing a non-slip part that restricts the circumferential displacement of the large diameter part on the large diameter part pressure contact surface of the ring body, or by providing a protrusion on the large diameter part of the boot, the large diameter from the circumferential groove is provided. The part can be prevented from coming off, and a stable boot mounting state can be obtained.

  An embodiment of a constant velocity universal joint according to the present invention will be described with reference to FIGS.

  FIG. 1 shows a constant velocity universal joint using the boot fixing structure of the first embodiment according to the present invention. The constant velocity universal joint includes an outer ring 33 as an outer joint member in which a plurality of track grooves 32 are formed on the inner diameter surface 31 along the axial direction at equal intervals in the circumferential direction, and a track groove of the outer ring 33 on the outer diameter surface 34. A plurality of track grooves 35 paired with the inner ring 36 are formed along the axial direction at equal intervals in the circumferential direction, and the inner ring 36 as an inner joint member; and between the track grooves 32 of the outer ring 33 and the track grooves 35 of the inner ring 36 And a cage 38 that holds the balls 37 interposed between an inner diameter surface 31 of the outer ring 33 and an outer diameter surface 34 of the inner ring 36.

  A shaft 40 is fitted into the inner ring 36. That is, the spline portion 41 is formed on the inner diameter surface of the center hole of the inner ring 36, and the spline portion 39 of the shaft 40 is fitted to the spline portion 41. A circumferential groove 42 is formed in the spline portion 39 of the shaft 40, and a retaining ring 43 for preventing the shaft from falling off is attached to the circumferential groove 42.

  A boot 45 is attached to the constant velocity universal joint. The boot 45 includes a large diameter portion 45a, a small diameter portion 45b, and a bellows portion 45c between the large diameter portion 45a and the small diameter portion 45b. The bellows portion 45c is formed by alternately arranging a plurality of valley portions 51 and a plurality of peak portions 52 in the axial direction. The boot 45 is formed of a thermoplastic elastomer such as ester, olefin, urethane, amide, or styrene. Thermoplastic elastomers have intermediate properties between resin and rubber. Although the thermoplastic elastomer is an elastic body, it can be processed by a normal molding machine for thermoplastic resins.

  The large diameter portion 45 a is attached (fixed) to the outer ring 33, and the small diameter portion 45 b is attached to the shaft 40. In this case, the shaft 40 includes a small-diameter boot mounting portion 46, and a concave groove 49 is formed in the boot mounting portion 46. The small diameter portion 45 b is fitted in the circumferential groove 49. A circumferential groove 50 is formed on the outer peripheral surface of the small diameter portion 45b, and a boot band 48 is fastened to the circumferential groove 50 so that the small diameter portion 45b and the shaft 40 are integrated. The boot band 48 is the omega band 14.

A circumferential groove 54 is formed in an end surface (opening end surface) 53 on the opening side of the outer ring 33, and a large-diameter portion 45 a of the boot 45 and a boot body 45 and a separate ring body 55 are formed in the circumferential groove 54. Press fit.

  The large-diameter portion 45a is made of a thin short cylindrical body, and as shown in FIG. 2A, the ring body 55 is made of a thin short cylindrical body made of a metal having high rigidity. The ring body 55 is disposed on the outer diameter side of the large diameter portion 45a, and is pressed into the circumferential groove 54 in a state where the large diameter portion 45a and the ring body 55 are overlapped. At this time, it is preferable to apply caulking to the opening end of the outer ring 33 to reduce the opening size of the opening 54 a of the circumferential groove 54. That is, a pressing force from the outer diameter direction to the inner diameter direction is applied to the opening end portion of the outer ring 33 to reduce the opening dimension of the opening portion 54a.

  In a state where the large-diameter portion 45 a and the ring body 55 are press-fitted into the circumferential groove 54, the radial wall 56 that connects the large-diameter portion 45 a and the valley portion 51 provided adjacent to the large-diameter portion 45 a is the outer ring 33. The outer end edge 55a of the ring body 55 and the opening end surface 53 are disposed on substantially the same plane while being in contact with the opening end surface 53. In this embodiment, the thickness T of the ring body 55 is set larger than the thickness T1 of the large-diameter portion 45a in the press-fitted state. The wall thickness T1 of the ring body 55 may be larger than the wall thickness T of the ring body 55. A concave recess 57 is formed on the inner diameter surface 54b of the circumferential groove 54 along the circumferential direction. The recessed portion 57 is an air escape during press-fitting.

  In the boot fixing structure, since the large-diameter portion 45a of the boot 45 does not protrude from the outer diameter surface of the outer ring 33, the clearance from the peripheral parts can be determined by the outer diameter surface of the outer ring 33. The clearance is widened, and the assemblability of this constant velocity universal joint is improved. Further, it is not necessary to use a conventional omega band or the like, and there is no loosening of the boot band due to collision of a foreign object with the boot band. For this reason, the boot 45 exhibits a stable sealing effect over a long period of time.

  By the way, as shown in FIG.2 (b), you may provide the slip prevention part 58 which regulates the circumferential direction shift | offset | difference of the large diameter part 45a in the internal diameter surface 55c of the ring body 55. FIG. As the non-slip | skid part 58, it can comprise with a knurl, for example. The knurling may be a flat knurled with only parallel straight grooves or a twill knurled with a number of small rhombuses.

  As described above, in the case where the anti-slip portion 58 is provided, the large-diameter portion 45a of the boot 45 does not shift in the circumferential direction even during rotation of the constant velocity universal joint, and the large diameter from the circumferential groove 54 based on the circumferential shift is large. It is possible to prevent the diameter portion 45a from coming off. For this reason, the stable mounting state of the boot 45 can be obtained.

  In this embodiment, the omega band 14 is used as a fixing member on the small diameter portion 45b side of the boot 45. However, even if the omega band 14 is used on the small diameter portion 45b side of the boot 45, the maximum outer diameter is large. Since it does not become larger than the outer diameter of the outer ring 33, the clearance between the peripheral parts does not become a problem.

  Next, FIG. 3 shows 2nd Embodiment, In this case, the taper surface which diameter-reduces toward the opening side of the circumferential groove 54 is formed in the internal diameter surface 55c of the ring body 55. FIG. As a result, the radial thickness T of the ring body 55 is increased from the depth of the groove toward the groove opening side, and the tightening force on the large diameter portion 45a of the boot 45 is increased on the opening 54a side of the circumferential groove 54. Yes.

  FIG. 4 shows a third embodiment. In this case, a convex portion 62 that protrudes toward the inner diameter side (the large diameter portion 45a side of the boot 45) is provided on the inner diameter surface 55c of the ring body 55, and this convex portion 62 is used as the boot. The large diameter portion 45a of 45 is bitten. Thereby, the tightening force with respect to the large diameter part 45a of the boot 45 is increased. In addition, as the convex part 62, even if it continues in the circumferential direction, a plurality may be arrange | positioned with a predetermined pitch along the circumferential direction. In this embodiment, two rows are provided along the axial direction, but may be one row or three or more rows.

  Thus, as shown in FIGS. 3 and 4, if the tightening force of the boot 45 against the large diameter portion 45a is increased, the fixing force of the boot 45 to the outer ring 33 is increased, and the boot 45 is stably sealed. Demonstrate the effect.

  FIG. 5 shows a fourth embodiment. In this case, a protrusion 63 protruding in the outer diameter direction is provided at the end of the large diameter portion 45 a of the boot 45. That is, the protrusion 63 is engaged with the inner end edge 55b of the ring body 55 to prevent the boot 45 from being displaced in the axial direction (the axial detachment from the circumferential groove 54). As a result, a stable wearing state of the boot 45 can be obtained.

  The other structure of the boot fixing structure and constant velocity universal joint shown in FIGS. 3 to 5 is the same as that shown in FIG. did.

  By the way, in order to increase the tightening force for the large diameter portion 45a of the boot 45, as shown in FIG. 6 of the fifth embodiment, the taper that reduces the outer diameter surface 54c of the circumferential groove 54 toward the opening side. It may be formed on the surface. Thereby, the opening dimension of the opening 54a of the circumferential groove 54 is reduced, and the tightening force is increased.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments, and various modifications are possible. For example, the boot 45 is made of a rubber material such as chloroprene rubber (CR). It may be a rubber boot. Further, when the anti-slip portion 58 is provided in the ring body 55, it can be configured also in a spiral groove or the like formed in the inner diameter surface 55c of the ring body 55. Also in the ring body 55 of FIGS. 3 to 5 and 6, a non-slip portion 58 may be provided on the inner diameter surface thereof.

  When the thickness T of the ring body 55 is the same along the axial direction, the thickness T1 of the large-diameter portion 45a of the boot 45 in the free state may be increased toward the opening side of the circumferential groove 54. Good. As a result, the tightening force of the large diameter portion 45a can be increased.

  Further, a tapered surface is provided on the inner diameter surface 54b of the circumferential groove 54 so as to increase in diameter from the groove back toward the groove opening side, so that the radial gap dimension of the circumferential groove 54 is directed from the groove back to the groove opening side. May be reduced.

  In each of the above embodiments, the ring body 55 is disposed on the outer diameter side of the large diameter portion 45a. Conversely, the ring body 55 can be disposed on the inner diameter side of the large diameter portion 45a. When the anti-slip portion 58 is provided on the ring body 55, it is provided on the outer diameter surface 55d as shown in FIG. For this reason, as the non-slip portion 58, if the large-diameter portion 45a of the large-diameter portion 45a of the boot 45 is not displaced in the circumferential direction, and the large-diameter portion 45a can be prevented from coming off from the circumferential groove 54, the ring body 55 The outer diameter surface 55d of the ring body 55, the inner diameter surface 55c of the ring body 55, the outer diameter surface of the large diameter portion 45a of the boot 45, and the inner diameter surface of the large diameter portion 45a of the boot 45 may be at least one of them. That is, it may be on all these surfaces or only one of them. Further, the ring body 55 is an endless complete ring in the illustrated example, but may be a non-complete ring provided with a notch (slit) in part. Further, the material of the ring body 55 is not limited to metal, and may be synthetic resin, rubber, or the like. That is, it is only necessary that the large-diameter portion 45 a can be sandwiched between the ring body 55 and the wall of the circumferential concave groove 54 in a state where the ring body 55 and the large-diameter portion 45 a are press-fitted into the circumferential concave groove 54.

  In the embodiment, an undercut-free type (UJ) is shown as a constant velocity universal joint, but other fixed type constant velocity universal joints such as a barfield type (BJ) may be used. Various sliding type constant velocity universal joints such as the above may be used.

It is sectional drawing of the constant velocity universal joint which uses the boot fixing structure which shows 1st Embodiment of this invention. 1 shows a ring body having a boot fixing structure, (a) is a perspective view of a ring body used in the constant velocity universal joint of FIG. 1, (b) is a perspective view of a modified example of the ring body, and (c) is a perspective view of the ring body. It is a perspective view of the other modification of a ring body. It is sectional drawing of the constant velocity universal joint which uses the boot fixing structure which shows 2nd Embodiment of this invention. It is sectional drawing of the constant velocity universal joint which uses the boot fixing structure which shows 3rd Embodiment of this invention. It is sectional drawing of the constant velocity universal joint which uses the boot fixing structure which shows 4th Embodiment of this invention. It is a principal part expanded sectional view of the constant velocity universal joint which uses the boot fixing structure which shows 5th Embodiment of this invention. It is sectional drawing of the constant velocity universal joint using the conventional boot fixing structure. It is a simplified diagram showing a boot band of a conventional boot fixing structure. It is a simplified diagram showing another boot band of a conventional boot fixing structure.

Explanation of symbols

45 Boot 45a Large diameter portion 45b Small diameter portion 53 Open end face 54 Circumferential groove 55 Ring body 58 Non-slip portion 62 Convex portion 63 Protrusion portion

Claims (7)

  A boot fixing structure in which a large-diameter portion of a boot is attached to an outer joint member of a constant velocity universal joint, and a small-diameter portion of the boot is attached to a shaft fitted in an inner joint member of the constant velocity universal joint, A boot fixing structure characterized in that a circumferential groove is formed in an opening end face of an outer joint member, and a large diameter portion of the boot and a ring body are press-fitted into the circumferential groove.   2. The boot fixing structure according to claim 1, wherein a caulking process for reducing the opening size of the opening portion of the circumferential groove is applied to the opening end portion of the outer joint member.   The boot fixing structure according to claim 1 or 2, wherein the ring body is provided with a tapered surface that increases the radial thickness of the ring body from the depth of the groove toward the groove opening side.   The boot fixing structure according to claim 1 or 2, wherein the circumferential groove is provided with a tapered surface that decreases the radial gap size of the circumferential groove from the groove back toward the groove opening side.   The circumferential displacement of the large diameter portion of the boot is restricted to at least one of the outer diameter surface of the ring body, the inner diameter surface of the ring body, the outer diameter surface of the large diameter portion of the boot, and the inner diameter surface of the large diameter portion of the boot. The boot fixing structure according to claim 1 or 2, further comprising a non-slip portion that is provided.   The boot fixing structure according to claim 1, wherein the ring body is provided with a convex portion that bites into a large diameter portion of the boot. The boot fixing structure according to claim 1 or 2, wherein a protrusion for restricting the axial displacement of the boot is provided on the large-diameter portion of the boot.

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