JP2013083331A - Constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive constant velocity universal joint capable of securing sealability of a boot.SOLUTION: This constant velocity universal joint includes an outside joint member having an opening part on one end, and an inside joint member for transmitting torque while allowing angular displacement via a torque transmission member between the outside joint member and itself, and a small diameter end part 62 of the bellows-shaped boot 60 for blocking up the opening part of the outside joint member, is fastened and fixed to an installation part 51 of a shaft 50 extending from the inside joint member. A recessed groove 52 of a simple shape is formed in the installation part 51 of the shaft 50, a one-strip inside slit groove 65 extending in the peripheral direction is formed on an inner peripheral surface of the small diameter end part 62 of the boot 60, and a two-strip outside slit grooves 66 extending in the peripheral direction are formed on an outer peripheral surface of the small diameter end part 62 of the boot 60.

Description

  The present invention is used in a power transmission system of automobiles and various industrial machines, and is provided with a boot that is incorporated in, for example, a drive shaft or a propeller shaft of an automobile and prevents foreign matter from entering from the outside of the joint or leakage of lubricant from the inside of the joint. It relates to a constant velocity universal joint.

  For example, there are two types of constant velocity universal joints that are used as means for transmitting a rotational force from an automobile engine to wheels at a constant velocity: a fixed constant velocity universal joint and a sliding constant velocity universal joint. Both of these constant velocity universal joints have a structure in which two shafts on the driving side and the driven side are connected so that rotational torque can be transmitted at a constant speed even if the two shafts have an operating angle.

  Since the drive shaft that transmits power from the engine of the automobile to the driving wheel needs to correspond to the angular displacement and axial displacement due to the change in the relative positional relationship between the engine and the wheel, the engine side (inboard side) ) And a fixed constant velocity universal joint on the drive wheel side (outboard side), and a structure in which both constant velocity universal joints are connected by a shaft.

  These sliding type constant velocity universal joints and fixed type constant velocity universal joints are designed to prevent the leakage of grease and other lubricants sealed inside the joint and prevent foreign matter from entering from the outside of the joint. A structure in which a rubber or resin bellows-like boot is mounted between the joint member and the shaft and the opening of the outer joint member is closed with the boot is common (see, for example, Patent Document 1).

  The boot is fastened and fixed to the outer peripheral surface of the shaft that extends from the inner joint member of the constant velocity universal joint by the large diameter end portion fastened to the outer peripheral surface of the opening of the outer joint member of the constant velocity universal joint by the boot band. The small-diameter end portion is connected to the large-diameter end portion and the small-diameter end portion, and the telescopic bellows portion is reduced in diameter from the large-diameter end portion toward the small-diameter end portion.

Japanese Utility Model Publication No. 4-128536

  By the way, in the conventional constant velocity universal joint, particularly in the case of a resin boot which is a hard material, the outer joint member and the shaft are operated by the operation of the constant velocity universal joint in which the outer joint member and the shaft rotate while taking an operating angle. It may be difficult to maintain the sealing property between the boot and the end of the boot only by tightening the boot band. For this reason, there is a possibility that a lubricant such as grease enclosed in the joint leaks from the outer joint member and between the shaft and the end of the boot.

  Therefore, in the constant velocity universal joint disclosed in Patent Document 1, for example, as shown in FIGS. 7 and 8, in the seal structure between the small-diameter end 162 of the boot 160 and the shaft 150, A convex portion 164 is provided on the inner peripheral surface of the small diameter end portion 162 of the boot 160 so that the small diameter end portion 162 and the shaft 150 are in close contact with each other. 151, and convex engagement ribs 153 are formed on both sides of the concave groove 152 to ensure sealing performance.

  However, when a structure in which convex engagement ribs 153 are formed at both ends of the concave groove 152 is employed, the shaft 150 to which the small-diameter end 162 of the boot 160 is fastened and fixed has convex engagement at both ends of the concave groove 152. In order to form the joint rib 153, a material having a diameter larger than that of the shaft 150 must be used, which increases the material cost. Although not shown, in the outer joint member to which the large-diameter end portion of the boot 160 is fastened and fixed, the processing costs increase and the processing man-hours increase because a plurality of concave grooves are formed. As a result, the cost of the product is increased due to the increase in material cost and processing cost and increase in the number of processing steps.

  The present invention has been proposed in view of the above-mentioned problems, and an object of the present invention is to provide a low-cost constant velocity universal joint that can ensure the sealing performance of the boot.

  As a technical means for achieving the above-mentioned object, the present invention provides torque while allowing angular displacement between an outer joint member having an opening at one end and a torque transmission member between the outer joint member. A constant velocity free end with the bellows-shaped boot that closes the opening of the outer joint member and fastened to the mounting part of the outer joint member and the mounting part of the shaft member extending from the inner joint member. It is a joint, and a simple groove is formed in one of the outer joint member and the shaft member, and is fitted to the outer joint member or the groove of the shaft member on the inner peripheral surface of the end of the boot. The convex part which provides is formed, and the inner side slit groove | channel extended in the circumferential direction was formed in the convex part.

  In the present invention, a concave groove having a simple shape is formed in the mounting portion of the outer joint member and the shaft member, and a convex portion that fits the outer joint member or the concave groove of the shaft member is provided on the inner peripheral surface of the end portion of the boot. By forming the inner slit groove extending in the circumferential direction on the convex portion, the end portion of the boot is easily deformed when the end portion of the boot is fastened and fixed. Securely adheres to the attachment site of the member.

  Thereby, the sealing performance is improved by reliably suppressing the lubricant enclosed in the joint from leaking from between the outer joint member and the shaft member and the end portion of the boot. As a result, since it is not necessary to form engagement ribs on both sides of the groove as in the conventional case, the groove formed in the mounting portion of the outer joint member and the shaft member can be a simple shape. Costs and man-hours can be reduced.

  In the present invention, a structure in which a single inner slit groove is formed in an axially central portion on the inner peripheral surface of the end portion of the boot is desirable. In this way, the end portion of the boot can be uniformly deformed when a tightening force is applied to the end portion of the boot, and it is favorable between the end portion of the boot and the mounting portion of the outer joint member and the shaft member. Adhesiveness can be obtained.

  In this invention, the structure which formed the outer side slit groove | channel extended in the circumferential direction in the site | part which shifted | deviated to the axial direction rather than the inner side slit groove | channel on the outer peripheral surface of the edge part of boots is desirable. In this way, by adding not only the inner slit groove but also the outer slit groove, the end portion of the boot is more easily deformed, so that the end portion of the boot is made by the mounting portion of the outer joint member and the shaft member. Adhere more securely. In this case, the strength can be ensured by shifting the axial positions of the inner slit groove and the outer slit groove without the end portion of the boot being partially thinned.

  In the present invention, it is desirable to have a structure in which two outer slit grooves are formed on both sides of the outer peripheral surface of the end portion of the boot that are shifted in the axial direction from the inner slit groove. In this way, the end portion of the boot can be uniformly deformed when a tightening force is applied to the end portion of the boot, and it is favorable between the end portion of the boot and the mounting portion of the outer joint member and the shaft member. Adhesiveness can be obtained.

  The inner slit groove and the outer slit groove in the present invention are preferably formed continuously over the entire circumference of the end portion of the boot to form an annular shape. In this way, when a tightening force is applied to the end portion of the boot, the end portion of the boot can be uniformly deformed in the circumferential direction, and the end portion of the boot and the attachment portion of the outer joint member and the shaft member can be Good adhesion can be obtained over the entire circumference.

  The inner slit groove and the outer slit groove in the present invention preferably have a structure formed discontinuously over the entire periphery of the end of the boot. In this way, by forming the inner slit groove and the outer slit groove that are divided in the circumferential direction of the boot end, when the tightening force is applied to the boot end, the boot end is circumferentially moved. It can be deformed evenly, and good adhesion can be obtained over the entire circumference between the end of the boot and the attachment site of the outer joint member and the shaft member.

  In the present invention, it is desirable that the discontinuous inner slit groove and outer slit groove adjacent to the end portion of the boot in the circumferential direction are shifted in the axial direction of the end portion of the boot. In this way, the inner slit groove and the outer slit groove divided in the circumferential direction at the end of the boot are dispersed in the axial direction, so that when the tightening force is applied to the end of the boot, the boot The end portion of the boot can be evenly deformed in the axial direction, and good adhesion can be obtained in the axial direction between the end portion of the boot and the attachment portion of the outer joint member and the shaft member.

  The boot in the present invention is preferably made of resin. In this way, even a resin boot, which is a hard material, is effective in that the end of the boot can be easily deformed.

  According to the present invention, a concave groove having a simple shape is formed in the mounting portion of the outer joint member and the shaft member, and the convex portion is fitted to the inner peripheral surface of the end portion of the boot with the concave groove of the outer joint member or the shaft member. Since the inner slit groove extending in the circumferential direction is formed on the convex portion, the end portion of the boot is easily deformed when the end portion of the boot is fastened and fixed. And it adheres firmly to the attachment part of a shaft member.

  Thereby, even if the concave groove formed in the attachment part of the outer joint member and the shaft member has a simple shape, the lubricant sealed inside the joint is removed from between the outer joint member and the shaft member and the end of the boot. Since the sealing performance is improved by reliably suppressing leakage, the material cost and the processing cost can be reduced and the number of processing steps can be reduced. As a result, it is possible to provide a low-cost constant velocity universal joint that can ensure the sealing performance of the boot.

In embodiment of this invention, it is a principal part expanded sectional view which shows the seal structure of the small diameter edge part of a boot, and a shaft. It is a principal part expanded sectional view which shows the state before attaching the small diameter edge part of the boot of FIG. 1 to a shaft. (A) is a development view showing an example of the formation pattern of the inner slit groove, and (B) is a development view showing an example of the formation pattern of the outer slit groove. (A) is a development view showing another example of the formation pattern of the inner slit groove, and (B) is a development view showing another example of the formation pattern of the outer slit groove. It is a longitudinal section showing the whole fixed type constant velocity universal joint composition in the embodiment of the present invention. FIG. 6 is a cross-sectional view showing the overall configuration of the fixed type constant velocity universal joint of FIG. 5. In a conventional structure, it is a principal part expanded sectional view which shows the state before attaching the small diameter edge part of a boot to a shaft. In the conventional structure, it is a principal part expanded sectional view which shows the seal structure of the small diameter edge part of a boot, and a shaft.

  Embodiments of the constant velocity universal joint according to the present invention will be described in detail below. In the following embodiments, a sliding type constant velocity universal joint is provided on the engine side (inboard side) of the automobile, and a fixed type constant velocity universal joint is provided on the driving wheel side (outboard side). It is built into a drive shaft that has a structure in which a joint is connected by a shaft, and has a structure that can transmit rotational torque at a constant speed even if the two axes on the drive side and the driven side are connected and the two axes take an operating angle. An undercut-free type constant velocity universal joint which is one of the fixed type constant velocity universal joints will be exemplified.

  The present invention can be applied to other fixed type constant velocity universal joints such as a Rzeppa type constant velocity universal joint in addition to the undercut-free type constant velocity universal joint. Furthermore, the present invention has a structure in which two shafts on the driving side and the driven side are connected to transmit rotational torque at a constant speed even when the two shafts have an operating angle, and also allow relative displacement in the axial direction. The present invention is also applicable to a sliding type constant velocity universal joint such as a tripod type and double offset type constant velocity universal joint provided with

  The constant velocity universal joint of the embodiment shown in FIGS. 5 and 6 includes a cup-shaped outer joint member 10 in which arc-shaped track grooves 11 extending in the axial direction are formed at a plurality of locations in the circumferential direction of the spherical inner peripheral surface 12. An inner joint member 20 in which arc-shaped track grooves 21 extending in the axial direction in pairs with the track grooves 11 of the outer joint member 10 are formed at a plurality of locations in the circumferential direction of the spherical outer peripheral surface 22; A ball 30 as a plurality of torque transmitting members interposed between the track grooves 11 of the ten and the track grooves 21 of the inner joint member 20, and the spherical inner peripheral surface 12 and the inner joint of the outer joint member 10; A main component is a cage 40 that is disposed between the spherical outer peripheral surface 22 of the member 20 and holds the balls 30 accommodated in pockets formed at equal intervals in the circumferential direction.

  In this constant velocity universal joint, one end of the shaft 50 is connected to the shaft hole of the inner joint member 20 so that torque can be transmitted by spline fitting. In the case of the undercut free type, the track groove 11 of the outer joint member 10 has a straight portion parallel to the axial direction on the opening side, and the track groove 21 of the inner joint member 20 is parallel to the axial direction on the inner side. It has a straight part.

  This type of constant velocity universal joint prevents, for example, a resin between the outer joint member 10 and the shaft 50 in order to prevent leakage of a lubricant such as grease enclosed in the joint and prevent foreign matter from entering from the outside of the joint. It has a structure equipped with a bellows-like boot 60 made of metal. As described above, by encapsulating a lubricant (not shown) in the inner space of the outer joint member 10 and the boot 60, the joint 50 is rotated during the operation in which the shaft 50 rotates with an operating angle with respect to the outer joint member 10. Lubricity is ensured at the sliding portion inside, that is, the sliding portion constituted by the outer joint member 10, the inner joint member 20, the ball 30 and the cage 40.

  The boot 60 includes a large-diameter end 61 fastened and fixed to the attachment portion 13 on the outer peripheral surface of the outer joint member 10 by a boot band 71, and a boot band 72 on the attachment portion 51 on the outer peripheral surface of the shaft 50 extending from the inner joint member 20. A small-diameter end portion 62 that is fastened and fixed by the above, and a large-diameter end portion 61 and a small-diameter end portion 62 that are connected to each other. It is configured.

  Here, a seal structure in which the small-diameter end portion 62 of the boot 60 is fastened and fixed to the attachment portion 51 of the shaft 50 by the boot band 72 is shown in FIGS. FIG. 1 shows a state after the small diameter end 62 of the boot 60 is assembled to the mounting part 51 of the shaft 50, and FIG. 2 shows a state before the small diameter end 62 of the boot 60 is assembled to the mounting part 51 of the shaft 50. . In the following, a seal structure in which the small diameter end portion 62 of the boot 60 is assembled to the attachment portion 51 of the shaft 50 will be described. However, a seal structure in which the large diameter end portion 61 of the boot 60 is assembled to the attachment portion 13 of the outer joint member 10 ( Since the same applies to FIG.

  As shown in FIGS. 1 and 2, an annular concave groove 52 is formed in the attachment portion 51 of the shaft 50, and a convex portion 64 is formed on the inner peripheral surface of the small diameter end portion 62 of the boot 60 so as to correspond to the concave groove 52. Form. The concave groove 52 of the shaft 50 has, for example, a simple shape of a concave R shape without forming engagement ribs 153 (see FIGS. 7 and 8) on both sides of the concave groove 152 as in the prior art. When the small diameter end portion 62 of the boot 60 is fastened and fixed to the mounting portion 51 of the shaft 50 by the boot band 72, the convex portion 64 of the small diameter end portion 62 of the boot 60 is fitted into the concave groove 52 of the mounting portion 51 of the shaft 50. Position by.

  By the operation of the constant velocity universal joint in which the outer joint member 10 and the shaft 50 rotate while taking an operating angle, the sealing performance between the shaft 50 and the small diameter end portion 62 of the boot 60 can be maintained only by tightening the boot band 72. It can be difficult. Therefore, in this constant velocity universal joint, as shown in FIGS. 1 and 2, the inner slit groove 65 extending in the circumferential direction is formed on the inner peripheral surface of the small diameter end portion 62 of the boot 60, and the boot band 72 is in contact with the constant velocity universal joint. The outer slit groove 66 extending in the circumferential direction is formed on the outer peripheral surface.

  Thus, the inner slit groove 65 extending in the circumferential direction is formed on the inner peripheral surface of the small diameter end portion 62 of the boot 60, and the outer slit groove 66 extending in the circumferential direction is formed on the outer peripheral surface of the small diameter end portion 62 of the boot 60. Since the small-diameter end 62 of the boot 60 is easily deformed when the small-diameter end 62 of the boot 60 is fastened and fixed to the mounting portion 51 of the shaft 50, the small-diameter end 62 of the boot 60 is deformed. It securely adheres to the mounting part 51 of the shaft 50. In the embodiment shown in FIGS. 1 and 2, not only the inner slit groove 65 but also the outer slit groove 66 extending in the circumferential direction is added to the outer peripheral surface of the small-diameter end portion 62 of the boot 60, thereby The deformation at the small-diameter end 62 becomes even easier.

  Thereby, the sealing performance is improved by reliably suppressing the lubricant sealed inside the joint from leaking between the shaft 50 and the small diameter end portion 62 of the boot 60. As a result, since it is not necessary to form the engaging ribs 153 (see FIGS. 7 and 8) on both sides of the concave groove 152 as in the prior art, the concave groove 52 formed in the attachment portion 51 of the shaft 50 has a concave R shape. Since it is not necessary to use a material with a large diameter for the shaft 50, the material cost and the processing cost can be reduced, and the number of processing steps can be reduced.

  In this constant velocity universal joint, a single inner slit groove 65 is formed in the axially central portion on the inner peripheral surface of the small diameter end portion 62 of the boot 60, and the inner slit is formed on the outer peripheral surface of the small diameter end portion 62 of the boot 60. Two outer slit grooves 66 are formed in both side portions shifted in the axial direction from the groove 65. By adopting such a structure, when a tightening force is applied to the small-diameter end portion 62 of the boot 60, the small-diameter end portion 62 of the boot 60 can be uniformly deformed. Good adhesion can be obtained with 50 attachment parts 51. In this case, by shifting the axial positions of the inner slit groove 65 and the outer slit groove 66, the small diameter end portion 62 of the boot 60 is not partially thinned and the strength can be ensured.

  As shown in FIGS. 3A and 3B, the inner slit groove 65 and the outer slit groove 66 are continuously formed over the entire circumference of the small diameter end portion 62 of the boot 60 to form an annular shape. By forming the annular inner slit groove 65 and the outer slit groove 66 in this manner, the small diameter end portion 62 of the boot 60 is uniformly deformed in the circumferential direction when a tightening force is applied to the small diameter end portion 62 of the boot 60. Thus, good adhesion can be obtained over the entire circumference between the small-diameter end 62 of the boot 60 and the mounting portion 51 of the shaft 50.

  In the case described above, a case where one inner slit groove 65 is formed on the inner peripheral surface of the small-diameter end portion 61 of the boot 60 and two outer slit grooves 66 are formed on the outer peripheral surface is illustrated. However, two or more inner slit grooves 65 and three or more outer slit grooves 66 are also possible, and the number thereof is arbitrary. Further, the inner slit groove 65 and the outer slit groove 66 are illustrated as having a V-shaped cross-sectional shape, but other cross-sectional shapes such as an R shape and a rectangular shape are possible, and the cross-sectional shapes are also arbitrary. .

  In the above, the case where the annular inner slit groove 65 and the outer slit groove 66 are formed is illustrated, but as other formation patterns, as shown in FIGS. 4A and 4B, the inner slit groove 65 ′ and the outer slit groove are formed. It is also possible to form the groove 66 ′ discontinuously over the entire circumference of the small diameter end portion 62 of the boot 60. In this way, when the inner slit groove 65 ′ and the outer slit groove 66 ′ divided in the circumferential direction of the small diameter end portion 62 of the boot 60 are formed, a tightening force acts on the small diameter end portion 62 of the boot 60. The small-diameter end 62 of the boot 60 can be uniformly deformed in the circumferential direction, and good adhesion can be obtained over the entire circumference between the small-diameter end 62 of the boot 60 and the mounting portion 51 of the shaft 50.

  When the inner slit groove 65 ′ and the outer slit groove 66 ′ are formed discontinuously over the entire circumference of the small diameter end portion 62 of the boot 60, for example, as shown in FIGS. 4A and 4B, the boot 60 A structure in which the inner slit groove 65 ′ and the outer slit groove 66 ′ adjacent to the small diameter end portion 62 in the circumferential direction are shifted in the axial direction of the small diameter end portion 62 of the boot 60 is possible. In this case, the inner slit groove 65 ′ and the outer slit groove 66 ′ divided in the circumferential direction of the small diameter end portion 62 of the boot 60 are dispersed in the axial direction, so that the small diameter end portion 62 of the boot 60 is tightened. When a force is applied, the small diameter end portion 62 of the boot 60 can be evenly deformed in the axial direction, and the axial direction is favorable between the small diameter end portion 62 of the boot 60 and the mounting portion 51 of the shaft 50. Adhesion can be obtained.

  The boot 60 may be made of rubber in addition to resin. However, when the boot 60 is made of a hard material such as resin, the small-diameter end portion 62 of the boot 60 is made more than when the boot 60 is made of a soft material such as rubber. Since it is difficult to maintain the sealing performance between the shaft 50 and the mounting portion 51 of the shaft 50 only by tightening the boot band 72, the inner slit grooves 65, 65 ′ and the outer slit grooves 66, The formation of 66 ′ is effective in that the small-diameter end portion 62 of the boot 60 can be easily deformed.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 10 Outer joint member 11 Arc-shaped track groove 12 Spherical inner peripheral surface 13 Mounting part 20 Inner joint member 21 Arc-shaped track groove 22 Spherical outer peripheral surface 30 Torque transmission member (ball)
50 Shaft member
51 Attaching part 52 Concave groove 60 Boot 61, 62 End of boot 64 Convex part 65 Inner slit groove 66 Outer slit groove

Claims (8)

An outer joint member having an opening at one end; and an inner joint member that transmits torque while allowing angular displacement between the outer joint member and the outer joint member via the torque transmission member; and the opening of the outer joint member A constant velocity universal joint in which an end portion of the bellows-like boot to be closed is fastened and fixed to an attachment part of the outer joint member and an attachment part of a shaft member extending from the inner joint member,
A concave groove having a simple shape is formed at either one of the outer joint member and the shaft member, and the inner joint surface of the end portion of the boot is fitted with the groove of the outer joint member or the shaft member. A constant velocity universal joint characterized in that a convex portion is provided and an inner slit groove extending in the circumferential direction is formed in the convex portion.   The constant velocity universal joint according to claim 1, wherein a single inner slit groove is formed in an axially central portion on an inner peripheral surface of an end portion of the boot.   3. The constant velocity universal joint according to claim 1, wherein an outer slit groove extending in the circumferential direction is formed in a portion shifted in an axial direction from the inner slit groove on an outer peripheral surface of an end portion of the boot.   The constant velocity universal joint according to any one of claims 1 to 3, wherein two outer slit grooves are formed on both side portions of the outer peripheral surface of the end portion of the boot that are axially displaced from the inner slit groove. .   The constant velocity universal joint according to any one of claims 1 to 4, wherein the inner slit groove and the outer slit groove are continuously formed over the entire circumference of the end portion of the boot to form an annular shape.   The constant velocity universal joint according to any one of claims 1 to 4, wherein the inner slit groove and the outer slit groove are formed discontinuously over the entire circumference of the end portion of the boot.   The constant velocity universal joint according to claim 6, wherein the inner slit groove and the outer slit groove adjacent to the end portion of the boot in the circumferential direction are shifted in the axial direction of the end portion of the boot.   The constant velocity universal joint according to any one of claims 1 to 7, wherein the boot is made of resin.

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