JP2009014176A - Boots for use in constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dispense with a degassing step when constant velocity universal joints, of a type attached through a metal ring, are assembled using a boots. <P>SOLUTION: A boots 50 for constant velocity universal joints consists of a boots body 52 and a metal ring 62 and is a type that is attached to an outer circle 10 of the constant velocity universal joint through the metal ring 62; the metal ring 62 has a small-diameter portion 64 to support the boots body 52, a large-diameter portion 68 to fit with outer circumference of the outer circle 10, and a shoulder portion 66 that lies between the small-diameter portion 64 and the large-diameter portion 68 and contacts edge face 18 of the outer circle 10 under a condition attached to the outer circle 10; and a through hole 74 is provided in the shoulder portion 66. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a constant velocity universal joint boot, and more particularly to a type of boot that is attached to an outer ring of a constant velocity universal joint via a metal ring.

Constant velocity universal joints are used for power transmission in automobiles and various industrial machines. In the case of automobiles, examples include those for drive shafts and propeller shafts.
Constant velocity universal joints impede torque transmission if foreign matter enters inside or a lubricant leaks to cause poor lubrication. Therefore, it is common to use a bellows-like boot made of an elastic body for sealing the inside or a metal ring boot in which a boot and a metal ring (boot adapter) are integrated.

  The metal ring boot includes a boot body having a substantially U-shaped cross section made of an elastic body such as rubber or synthetic resin, and a metal ring called a boot adapter. The boot body has a shape in which one end side of the tube is rolled outward, and includes a large-diameter end portion, a small-diameter end portion, and a folded portion having a substantially U-shaped cross section located between both ends. The boot adapter 10 has a generally cylindrical shape, and includes a large diameter portion, a small diameter portion, and a shoulder portion located between the large diameter portion and the small diameter portion. The large diameter end of the boot body is fixed to the small diameter portion of the boot adapter. The small-diameter end of the boot body is attached to the shaft of the inner joint member, and is fastened and fixed with a boot band.

  When assembling the constant velocity universal joint, the boot adapter and the boot body are fitted on the shaft in advance, the outer ring, the inner ring, the cage and the ball are assembled, and then the spline shaft portion of the shaft is inserted into the spline hole of the inner ring. Thereafter, the large diameter portion of the boot adapter is press-fitted into the outer periphery of the opening end portion of the outer ring.

  When the large-diameter portion of the boot adapter is press-fitted into the outer ring, the internal pressure rises because there is no escape space for the internal air, so air must be vented to adjust the internal pressure of the constant velocity universal joint. In the case of metal ring boots, the metal ring is pressed into the outer diameter of the outer ring and sealed, so if there is no inner pressure adjustment vent, the metal ring boot is pressed into the outer ring, then the shaft and boot body It tightens with a boot band through an air venting process that vents air from between the small diameter ends.

As a mechanism that does not require an air venting process, there is a mechanism that adjusts the internal pressure by providing a vent hole in the boot (Patent Document 1), and a mechanism that prevents a rise in internal pressure during installation by providing a slit in the outer ring (Patent Document 2). Are known.
Japanese Patent Application Laid-Open No. 2004-156689 JP 2006-242226 A

  If the boot has a vent hole, it may cause leakage of lubricating oil or intrusion of muddy water. For those without vents, as described above, press the metal ring boot into the outer ring and remove excess air from between the small diameter part of the boot and the shaft before tightening the small diameter end of the boot body with the boot band. Since the air venting process is indispensable, it takes time. Furthermore, if the user forgets to vent the air, the internal pressure of the constant velocity universal joint may increase during use, causing the boot to deform and cause damage.

  Accordingly, an object of the present invention is to eliminate the need for an air venting process when assembling a constant velocity universal joint using a boot of a type attached via a metal ring.

  The present invention solves the problem by providing a through hole in the metal ring as a ventilation means for automatically adjusting the internal pressure of the constant velocity universal joint when the metal ring boot is press-fitted into the outer ring. The shape and number of the through holes are arbitrary.

  That is, the constant velocity universal joint boot of the present invention comprises a boot body and a metal ring, and is attached to the outer ring of the constant velocity universal joint through the metal ring, and the metal ring holds the boot body. A small-diameter portion to be fitted, a large-diameter portion to be fitted to the outer periphery of the outer ring, and a shoulder portion that is located between the small-diameter portion and the large-diameter portion and is in contact with the end surface of the outer ring in a state of being attached to the outer ring, The shoulder portion is provided with a through hole. When the press-fitting is completed, the end face of the outer ring and the shoulder of the metal ring are in close contact with each other, and the through hole is completely closed. Therefore, problems such as leakage of lubricating oil and intrusion of muddy water do not occur.

  The through hole can be formed by making a hole of an arbitrary shape in the shoulder portion of the metal ring, and by cutting and raising the shoulder portion to form a piece. The cut and raised piece is deformed during the press-fitting process, and closes the through-hole as soon as the press-fitting is completed. Therefore, in this case as well, problems such as leakage of lubricating oil and intrusion of muddy water do not occur.

  An O-ring or packing may be interposed between the shoulder and the end face of the outer ring on the inner diameter side of the through hole (claims 3 and 4). Thereby, the sealing performance between the end surface of the outer ring and the shoulder portion of the metal ring is improved.

  In order to improve confidentiality, the through hole may be closed with the metal ring attached to the outer ring (claim 5). Examples of materials used for this purpose include liquid packing and silicon.

  The boot for a constant velocity universal joint according to any one of claims 1 to 5, wherein the shoulder portion of the metal ring has no opening other than the through hole. For example, in the case of a type in which a metal ring is fixed to an outer ring using a bolt, a bolt hole is provided in a shoulder portion. When such an opening is present, it is less necessary to provide a through hole.

  According to the present invention, air naturally escapes during assembly. That is, in the process of press-fitting the metal ring boot, air escapes, and the air amount inside the constant velocity universal joint becomes appropriate. Therefore, the air venting process becomes unnecessary. Moreover, since the through hole is closed when the assembly is completed, problems such as lubricant leakage and intrusion of muddy water do not occur. Furthermore, the concern about the trouble that the boots expand due to an increase in internal pressure of the constant velocity universal joint during use due to forgetting to remove air is eliminated.

Embodiments of the present invention will be described below with reference to the drawings.
First, the basic configuration of the constant velocity universal joint will be described with reference to FIG. FIG. 2 shows an example of a double offset type constant velocity universal joint, but the present invention can also be applied to other types of constant velocity universal joints. As shown in the figure, the double offset type constant velocity universal joint mainly includes an outer ring 10 as an outer joint member, an inner ring 20 as an inner joint member, a ball 30 as a torque transmission element, and a cage 40 for holding the ball. As a component.

The outer ring 10 has a cup shape opened at one end, and is connected to one of the two shafts to be coupled so as to be able to transmit torque at a coupling portion 12 with the power system formed on the opposite opening side.
The outer ring 10 has a cylindrical inner peripheral surface 14, and ball grooves 16 extending in the axial direction are formed at equal intervals in the circumferential direction of the spherical inner peripheral surface 14.

  The inner ring 20 is connected to the other of the two shafts to be coupled, that is, the shaft 28 in this case so as to be able to transmit torque, by a spline hole 22 formed in the shaft center portion. The inner ring 20 has a spherical outer peripheral surface 24, and ball grooves 26 extending in the axial direction are formed at equal intervals in the circumferential direction of the spherical outer peripheral surface 24.

  The ball groove 16 of the outer ring 10 and the ball groove 26 of the inner ring 20 form a pair, and one ball 30 is incorporated between each pair of ball grooves 16 and 26. All the balls 30 are held in the same plane by the cage 40. In general, six or eight balls 30 are used, but the number of balls is not particularly limited here.

  The cage 40 is interposed between the inner peripheral surface 14 of the outer ring 10 and the outer peripheral surface 24 of the inner ring 20. The outer peripheral surface 42 of the cage 40 includes a convex spherical portion, and the concave spherical portion is in contact with the cylindrical inner peripheral surface 14 of the outer ring 10. The inner peripheral surface 44 of the cage 40 includes a concave spherical portion, and the convex spherical portion is in spherical contact with the outer peripheral surface 24 of the inner ring 20. Pockets 46 for accommodating the balls 30 are formed in the cage 40 at predetermined intervals in the circumferential direction.

  The spherical center of the convex spherical portion of the outer peripheral surface 42 of the cage 40 and the spherical center of the concave spherical portion of the inner peripheral surface 44 are offset in the axial direction by an equal distance in the opposite direction from the joint center. When the joint takes an operating angle, the ball 30 is held in a biaxial bisector plane intersecting at the joint center, and the lengths of the perpendiculars extending from the center of the ball 30 to the respective axes become equal. Therefore, the two axes always rotate at an equiangular speed.

Grease and other lubricants are filled inside the joint. In order to prevent leakage of the lubricant and to prevent muddy water from entering from the outside, a boot 50 is attached. The boot 50 includes a boot body 52 and a metal ring 62.
The boot main body 52 is made of rubber or resin, and includes a small diameter end portion 54, a folded portion 56, and a large diameter end portion 58. However, the boot main body 52 can also be applied to a bellows-shaped boot main body. The small-diameter end portion 54 is fitted to the shaft 28 and is fastened and fixed by the boot band 60. The large diameter end portion 58 is attached to the small diameter portion 64 of the metal ring 62. The metal ring 62 has a generally cylindrical shape and includes a small diameter portion 64, a large diameter portion 68, and a shoulder portion 66 that is located between the two and extends in the radial direction. The small-diameter portion 64 is integrated by folding the large-diameter end portion 58 of the boot body 52 so as to be wound inside.

  The large diameter portion 68 of the metal ring 62 is press-fitted into the outer periphery of the opening end portion of the outer ring 10. As indicated by reference numeral 70, the tip end portion of the large diameter portion 68 is caulked from the outer diameter side to be engaged with the groove of the outer ring 10 to prevent it from coming off. An O-ring 72 is mounted in a groove formed on the outer peripheral surface of the outer ring 10, and the O-ring 72 is pressed by the large-diameter portion 68 of the metal ring 62 to exert a sealing action.

Referring now to FIG. 1, a through hole 74 is formed in the shoulder 66 of the metal ring 62. The shape and number of the through holes 74 are arbitrary. Specific examples of the shape of the through hole 74 include a circle (FIG. 1B) or a rectangle (FIG. 1C). The shoulder 66 of the metal ring 62 has no opening other than the through hole 74.

As shown in FIG. 3, when assembling the constant velocity universal joint constituted by the outer ring 10, the inner ring 20, the ball 30, and the cage 40 and the shaft 28 (FIG. 2) in which the boot 50 is fixed by the boot band 60, for example, press A metal ring 62 of the boot 50 is press-fitted into the outer ring 10 using a machine or the like. In FIG. 3, the shaft 28 is omitted. At this time, the press-fitting process is (A) → (B) → (C), and excess air is released from the through hole 74 so as to keep the internal pressure constant, but the end face 18 of the outer ring 10 and the shoulder of the metal ring 62 When 66 is brought into close contact and press-fitting is completed, the through hole 74 is closed (FIG. 3C). In this way, excess air inside the joint escapes from the through-hole 74 until just before the press-fitting is completed, and the through-hole 74 is closed at the time of the press-fitting completion, so that problems such as lubricating oil leakage and muddy water intrusion do not occur.
The through-hole 74 can be provided in the shoulder 66, or the same effect can be expected if it is provided near the shoulder of the large-diameter portion 68 of the metal ring 62. However, the through-hole 74 is preferably provided in the shoulder 66 because it closes when the press-fitting is completed. It is advantageous.

  As shown in FIGS. 1 and 2, an annular groove may be formed in the end face 18 of the outer ring 10 and an O-ring may be attached thereto. In this way, by mounting the O-ring 76 and packing closer to the inner diameter side than the through hole 74, the space between the shoulder 66 of the metal ring 62 and the end face 18 of the outer ring 10 is kept airtight and liquid-tight. The inside can be sealed.

As a method of completely closing the through-hole 74 when the press-fitting is completed, the through-hole 74 is formed by providing the cut-and-raised piece 78 as shown in FIG. 4, and the cut-and-raised piece 78 is gradually elastically deformed in the process of press-fitting, The through hole 74 may be closed when the press-fitting is completed (the press-fitting process is (A) → (B) → (C) → (D)). In this case as well, a more reliable sealing state can be secured by using an O-ring 76 or packing together as shown in the figure.
Furthermore, in order to enhance confidentiality, the through hole 74 may be closed with a padding such as liquid packing or silicon while the metal ring 62 is attached to the outer ring 10.

(A) is sectional drawing which shows embodiment, (B) (C) is an arrow line view of FIG. 1 (A). It is a longitudinal cross-sectional view of a constant velocity universal joint. It is a fragmentary sectional view which shows the attachment process of boots. It is a fragmentary sectional view which shows the attachment process of boots.

Explanation of symbols

10 Outer ring (outer joint member)
12 Coupling part with power system 14 Inner peripheral surface 16 Ball groove 18 End surface 20 Inner ring (inner joint member)
22 spline hole 24 outer peripheral surface 26 ball groove 28 shaft 30 ball (torque transmission element)
40 Cage 42 Outer peripheral surface 44 Inner peripheral surface 46 Pocket 50 Boot 52 Boot main body 54 Small diameter end portion 56 Folded portion 58 Large diameter end portion 60 Boot band 62 Metal ring 64 Small diameter portion 66 Shoulder portion 68 Large diameter portion 70 Caulking portion 72, 76 O-ring 74 Through hole

Claims (6)

  A type consisting of a boot body and a metal ring, which is attached to the outer ring of the constant velocity universal joint via the metal ring, and the metal ring is fitted to a small-diameter portion holding the boot body and an outer periphery of the outer ring. A constant velocity universal joint having a diameter portion and a shoulder portion which is located between the small diameter portion and the large diameter portion and is in contact with the end surface of the outer ring in a state of being attached to the outer ring, and a through hole is provided in the shoulder portion Boots.   The constant velocity universal joint boot according to claim 1, wherein the through hole is formed by cutting and raising a piece on the shoulder.   The constant velocity universal joint boot according to claim 1 or 2, wherein an O-ring is interposed between the shoulder and the end face of the outer ring on the inner diameter side of the through hole.   The constant velocity universal joint boot according to claim 1 or 2, wherein a packing is interposed between the shoulder portion and an end face of the outer ring on the inner diameter side of the through hole.   The boot for a constant velocity universal joint according to any one of claims 1 to 4, wherein the through hole is closed with the metal ring attached to the outer ring.   The boot for a constant velocity universal joint according to any one of claims 1 to 5, wherein there is no opening other than the through hole in a shoulder portion of the metal ring.

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