JP2012041969A - Boot for constant velocity universal joint and constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the sealing performance between a boot for a constant velocity universal joint and a constant velocity universal joint.SOLUTION: The boot for the constant velocity universal joint 9 includes a large diameter mounting part 9a fixed to an outer joint member of the constant velocity universal joint by tightening of a boot band. A thick part 18a and a thin part 18b are alternately arranged in the circumference in the large diameter mounting part 9a. A projection 21 protruding outward in the radial direction is formed on the outer peripheral surface of the thick part 18a in a band mounting groove 16.

Description

  The present invention relates to a constant velocity universal joint boot and a constant velocity universal joint.

  In power transmission systems of automobiles and various industrial machines, constant velocity universal joints are widely used in order to transmit torque while allowing angular displacement between two axes of the driving side and the driven side. This constant velocity universal joint includes a cup-shaped outer joint member, an inner joint member disposed inside the outer joint member, and a torque transmission comprising a roller or a ball interposed between the inner joint member and the outer joint member. The main component is the element and the boot that seals the opening of the outer joint member.

  The boot is used to prevent the lubricant encapsulated inside the outer joint member from flowing out and foreign matter from entering the inside. FIG. 11 shows an example of a conventional boot 59. The boot 59 includes a large-diameter attachment portion 59a attached to the outer peripheral surface 52a of the opening of the outer joint member 52, a small-diameter attachment portion 59b attached to the outer peripheral surface of the shaft 54 coupled to the inner joint member, and a large-diameter attachment portion. 59a and a bellows portion 59c that connects the small diameter attachment portion 59b.

  Band attachment grooves 66 and 67 are formed on the outer peripheral surfaces of the large-diameter attachment portion 59a and the small-diameter attachment portion 59b of the boot 59 over the entire circumference. The boot band 63a accommodated in the band mounting grooves 66 and 67 in a state where the large diameter mounting portion 59a and the small diameter mounting portion 59b of the boot 59 are fitted to the outer peripheral surface 52a of the outer joint member 52 and the outer peripheral surface of the shaft 54, respectively. 63b is reduced in diameter by means such as caulking, whereby the large diameter attachment portion 59a and the small diameter attachment portion 59b are tightened in the inner diameter direction, and the large diameter attachment portion 59a and the small diameter attachment portion 59b are respectively connected to the outer joint member 52 and the shaft. 54 (see Patent Document 1).

  The inner peripheral surface of the large-diameter mounting portion 59a of the boot 59 is formed in a shape corresponding to the shape of the outer peripheral surface 52a of the outer joint member 52 that is a mating partner. As the outer peripheral surface shape of the outer joint member, there are two types, a cylindrical surface (hereinafter referred to as “cylindrical type”) and a non-circular cross section (hereinafter referred to as “non-circular type”). There is. FIG. 11B shows a non-round type outer joint member 52 and a large-diameter mounting portion 59a that fits the non-circular type outer joint member 52.

JP-A-6-101721

  As shown in FIG. 11B, conventionally, the outer peripheral surface (including the bottom surface of the band mounting groove 66) of the large-diameter mounting portion 59a of the boot 59 corresponding to the non-circular outer joint member 52 is cylindrical. It is formed in a planar shape. On the other hand, the inner peripheral surface 60 of the large-diameter attachment portion 59a is formed in a shape corresponding to the non-circular shape of the outer peripheral surface of the opening of the outer joint member over the entire surface. Therefore, the thickness of the large-diameter attachment portion 59a of the boot 59 is not uniform in the circumferential direction, and as a result, thick portions 68a and thin-wall portions 68b are alternately formed in the circumferential direction in the large-diameter attachment portion 59a. .

  When the large-diameter mounting portion 59a having such a configuration is tightened with the boot band 63a, the diameter reduction amount of the boot band is uniform over the entire circumference, and therefore, the compressed portion in the radial direction is small in the thick portion 68a after tightening. Thus, the compressibility in the radial direction is increased in the thin portion 68b. In the thick portion 68a where the compression rate is small, the contact surface pressure with respect to the outer peripheral surface 52a of the opening of the outer joint member 52 is reduced compared to the thin portion 68b where the compression rate is large. Therefore, the sealing performance between the boot 59 and the outer joint member 52 is deteriorated, and there is a possibility that the lubricant leaks and foreign matters enter the joint through the low surface pressure portion.

  Further, when the large-diameter mounting portion 59a of the boot 59 is fitted to the outer peripheral surface of the opening of the outer joint member, if the circumferential phase of both of them slightly deviates, the inner peripheral surface (convex curved surface) of the thick portion 68a 62a) and an inner peripheral surface (concave surface 62b) of the thin wall portion 68b, a gap is formed between the outer peripheral surface of the opening of the outer joint member, and the same problem occurs due to a decrease in sealing performance. May occur.

  In view of the above circumstances, an object of the present invention is to improve the sealing performance between the constant velocity universal joint boot and the outer joint member.

  In order to solve the above problems, the present invention includes a large-diameter mounting portion that is fitted to the outer peripheral surface of the opening of the outer joint member of the constant velocity universal joint, and the thick-walled portion and the thin-walled portion are circular in the large-diameter mounting portion. Provided alternately in the circumferential direction, the inner peripheral surface of the large-diameter mounting portion has a shape corresponding to the outer peripheral surface shape of the opening formed in a non-circular cross section of the outer joint member, and the large diameter is obtained by tightening force from the boot band. In the constant velocity universal joint boot in which the mounting portion is fixed to the outer peripheral surface of the opening of the outer joint member, the inner diameter side of the boot band of the outer peripheral surface of the large-diameter mounting portion is formed in a non-circular cross section. It is a feature.

  With this configuration, after tightening the boot band, a high compression portion with a large radial compression ratio and a low compression portion with a small radial compression ratio are formed on the outer peripheral surface of the large-diameter mounting portion of the boot. The In the high compression portion, the surface pressure of the inner peripheral surface (contact surface pressure against the outer peripheral surface of the opening of the outer joint member) can be increased. Therefore, it is possible to adjust the surface pressure distribution on the inner peripheral surface, and the surface pressure can be made uniform over the entire periphery, thereby improving the sealing performance between the boot and the outer joint member.

  This large-diameter mounting portion having a non-circular cross-sectional shape can be formed, for example, by providing a protrusion on the outer peripheral surface on the inner diameter side of the boot band. After the boot band is tightened, the protruding portion becomes a high compression portion, and the other region becomes a low compression portion, and a uniform surface pressure is obtained. The other region is preferably formed in a cylindrical surface shape.

  The present invention also includes a large-diameter mounting portion that is fitted to the outer peripheral surface of the opening of the outer joint member of the constant velocity universal joint, and the large-diameter mounting portion is provided with thick and thin portions alternately in the circumferential direction. The inner peripheral surface of the large-diameter mounting portion has a shape corresponding to the outer peripheral surface shape of the opening formed in a non-circular cross section of the outer joint member, and the large-diameter mounting portion is formed by the tightening force from the boot band. The constant velocity universal joint boot fixed to the outer peripheral surface of the opening of the member is characterized in that a protruding portion is provided on the inner diameter side of the boot band on the inner peripheral surface of the large-diameter mounting portion. It is.

  Even in this configuration, after the boot band is tightened, the projecting portion of the inner peripheral surface of the large-diameter mounting portion of the boot becomes a high compression portion having a large radial compression rate, and the other regions have a small radial compression rate. It becomes a low compression part. Since the contact surface pressure with respect to the outer peripheral surface of the opening of the outer joint member increases in the high compression portion, the surface pressure distribution on the inner peripheral surface can be adjusted, and the surface pressure can be made uniform over the entire periphery.

  If these protrusions are formed in the thick part, the contact surface pressure of the thick part with respect to the outer peripheral surface of the opening of the outer joint member can be increased. Thereby, the low surface pressure in the thick portion can be eliminated, the surface pressure can be made uniform over the entire circumference, and the sealing performance between the boot and the outer joint member can be improved.

  If the projecting part is formed at the boundary between the thick part and the thin part, both are placed in a state where a circumferential phase shift occurs between the large diameter mounting part of the boot and the outer peripheral surface of the opening part of the outer joint member. Even when the boot band is fitted and tightened, the protruding portion is in a highly compressed state, so that the contact surface pressure against the outer peripheral surface of the opening of the outer joint member is increased at the inner peripheral surface of the thick portion and the thin portion. Can do. Thereby, generation | occurrence | production of the clearance gap accompanying a phase shift is prevented, and sufficient contact surface pressure is securable over the perimeter. Therefore, the sealing performance between the boot and the outer joint member can be improved.

  If a hard member harder than the boot material is disposed in the thick portion, the thickness of the boot material in the thick portion is reduced by the amount of the hard member. Therefore, the compression ratio at the thick portion at the time of tightening the boot band can be increased, and the contact surface pressure between the thick portion and the outer joint member can be further increased. The sealing effect is improved.

  The hard member can be embedded in the thick portion by means such as insert molding. In this case, the hard member can be prevented from aging.

  The constant velocity universal joint according to the present invention has a boot having any one of the above structures, an opening at one end in the axial direction, and a track groove and an area between the track grooves located on the inner diameter side of the track groove on the inner periphery. An outer joint member formed alternately in the circumferential direction and having an outer peripheral surface thinned on the outer diameter side of the track groove region, an inner joint member disposed inside the outer joint member, an inner joint member, and an outer joint member, And a boot band that is mounted on the outer peripheral surface of the large-diameter mounting portion of the boot and applies a tightening force in the inner diameter direction to the large-diameter mounting portion.

  In this constant velocity universal joint, for example, a roller can be used as a torque transmission element (tripod type constant velocity universal joint or the like). In addition, a ball can be used as a torque transmitting element (such as a Rzeppa constant velocity universal joint). In this case, six or eight balls can be used.

  According to the present invention as described above, the sealing performance between the constant velocity universal joint boot and the outer joint member can be improved, and the leakage of the lubricant and the entry of the foreign matter into the joint can be reliably prevented for a long period of time. be able to.

It is a figure which shows the boot and constant velocity universal joint which concern on embodiment of this invention, (A) is an axial sectional view, (B) is a ZZ arrow sectional view of (A). It is a figure which shows the boot for constant velocity universal joints concerning embodiment of this invention, (A) is an axial sectional view, (B) is an XX sectional view taken on (A). It is radial direction sectional drawing which shows the modification of the large diameter attaching part of the boot for constant velocity universal joints. It is radial direction sectional drawing which shows the modification of the large diameter attaching part of the boot for constant velocity universal joints. It is radial direction sectional drawing which shows the modification of the large diameter attaching part of the boot for constant velocity universal joints. It is radial direction sectional drawing which shows the modification of the large diameter attaching part of the boot for constant velocity universal joints. It is radial direction sectional drawing which shows the modification of the large diameter attaching part of the boot for constant velocity universal joints. It is an axial sectional view showing a Rzeppa constant velocity universal joint. It is radial direction sectional drawing of the large diameter attaching part of the boots for Rzeppa constant velocity universal joints. It is radial direction sectional drawing of the large diameter attaching part of the boots for Rzeppa constant velocity universal joints. It is a figure which shows the conventional boot, (A) is an axial sectional view, (B) is a YY arrow directional cross-sectional view of (A).

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

  FIG. 1 shows a tripod type constant velocity universal joint 1 used on the inboard side of a drive shaft of an automobile as an example of a constant velocity universal joint. The tripod type constant velocity universal joint 1 is a sliding type constant velocity universal joint capable of plunging between two axes. The main components are an outer joint member 2, an inner joint member 6, and a roller as a torque transmission element. 8, a shaft 4, and a boot 9.

  The outer joint member 2 has a bottomed cylindrical shape, and is integrally provided with a stem portion 3 on the side opposite to the opening end. The stem portion 3 is connected to a transmission or a differential. Three linear track grooves 5 extending in the axial direction are formed on the inner peripheral surface of the outer joint member 2 at equal intervals in the circumferential direction. The inner peripheral surface between adjacent track grooves 5 constitutes an inter-track groove region R located on the inner diameter side of the track grooves 5.

  The outer joint member 2 is a so-called non-circular type, and has a shape obtained by removing the outer diameter side of the track groove region R in the cylindrical outer peripheral surface 2a as shown in FIG. 1 (B). More specifically, the outer peripheral surface 2a has a partially cylindrical surface-like convex curved surface 11b formed on the outer diameter side of the track groove 5 and a partially cylindrical surface-like shape formed on the outer diameter side of the region R between the track grooves. Concave surfaces 11a are alternately provided in the circumferential direction. The concave curved surface 11a is a partial cylindrical surface centered on the eccentric position from the axis, and the convex curved surface 11b is a partial cylindrical surface centered on the axis.

  The inner joint member 6 has a ring shape and is disposed inside the outer joint member 2. On the outer periphery of the inner joint member 6, three journals 7 projecting radially outward are provided at equal intervals in the circumferential direction, and each journal 7 is provided between the outer joint member 2 and the inner joint member 6. A roller 8 as a torque transmission element for transmitting torque is attached. The roller 8 is rotatably supported with respect to each journal 7 by disposing a large number of needle rollers 19 between the inner peripheral surface thereof and the outer peripheral surface of the journal 7. By engaging the roller 8 in the track groove 5 and rolling the roller 8 with respect to the track groove 5, the operating angle is allowed while allowing the axial displacement between the outer joint member 2 and the inner joint member 6. Torque can be transmitted between the outer joint member 2 and the shaft 4 that have been taken.

  One end of the shaft 4 is serrated to the inner periphery of the inner joint member 6 and the other end is connected to a constant velocity universal joint on the wheel hub (not shown) side.

  The space between the opening of the outer joint member 2 and the shaft 4 is sealed with a boot 9 made of rubber or resin for the purpose of preventing leakage of grease and preventing foreign matter from entering the inside of the joint. The boot 9 includes a large-diameter attachment portion 9a attached to the outer peripheral surface 2a of the opening of the outer joint member 2, a small-diameter attachment portion 9b attached to the outer peripheral surface of the shaft 4, a large-diameter attachment portion 9a, and a small-diameter attachment portion 9b. And a bellows portion 9c to be connected.

  Band mounting grooves 16 and 17 having a uniform depth are formed on the outer peripheral surfaces of the large-diameter mounting portion 9a and the small-diameter mounting portion 9b of the boot 9 over the entire circumference. The boot band accommodated in the band mounting grooves 16 and 17 with the large-diameter mounting portion 9a and the small-diameter mounting portion 9b of the boot 9 fitted in the outer peripheral surface 2a of the outer joint member 2 and the outer peripheral surface of the shaft 4, respectively. By reducing the diameters of 13a and 13b by means such as caulking, the large-diameter mounting portion 9a and the small-diameter mounting portion 9b are tightened in the inner diameter direction, and the large-diameter mounting portion 9a and the small-diameter mounting portion 9b are respectively connected to the outer joint member 2 and It is fixed to the shaft 4.

  As shown in FIG. 2 (B), the large-diameter mounting portion 9a of the boot 9 has a thick portion 18a that is thicker in the radial direction and a thin portion 18b that is thinner than this. It is formed alternately. The inner peripheral surface of the thick portion 18a constitutes a partially cylindrical convex curved surface 12a corresponding to the concave curved surface 11a of the outer peripheral surface 2a of the outer joint member 2, and the inner peripheral surface of the thin portion 18b is the outer joint member 2. A partially cylindrical concave curved surface 12b corresponding to the convex curved surface 11b of the outer peripheral surface 2a is formed. The inner peripheral surface 10 of the large-diameter mounting portion 9a composed of the convex curved surface 12a and the concave curved surface 12b has a shape corresponding to the opening outer peripheral surface 2a of the outer joint member 2, and is formed on the outer peripheral surface 2a of the outer joint member 2. Mated with uniform tightening allowance.

As shown in FIG. 2B, the outer peripheral surface (groove bottom surface) of the band mounting groove 16 is formed in a non-circular shape in cross section by forming protruding portions 21 at equidistant positions in the circumferential direction. The protruding portion 21 in the illustrated example is formed in a circular arc shape that is symmetrical in the circumferential direction with respect to the circumferential center line P ₁ of each thick portion 18 a, and from the outer circumferential surface on both sides in the circumferential direction to the outer diameter side It stands up smoothly. The maximum height h of the protrusion 21 is smaller than the groove depth of the band mounting groove 16 and is about 1 to 2 mm. The thick portion 18a is adapted to its most becomes thick on the circumferential-direction center line P _1, it becomes gradually thinner toward both sides in the circumferential direction therefrom forms. Further, as shown in FIG. 2A, the protruding portion 21 is formed only in a partial region (intermediate region) in the axial direction of the bottom surface of the band mounting groove 16. Of the outer peripheral surface of the band mounting groove 16, both sides in the circumferential direction and both sides in the axial direction of the protruding portion 21 are formed in a cylindrical shape.

  As described above, in the present invention, in the large-diameter mounting portion 9a of the boot 9, the protruding portion 21 is formed on the inner diameter side of the boot band 13a, specifically, the outer peripheral surface of the band mounting groove 16, so that the outer peripheral surface is cross-sectioned. It is formed in a non-circular shape (the perfect circular contour of the outer peripheral surface of the conventional boot mounting groove 16 is indicated by a broken line in FIG. 2B). Accordingly, when the boot band 13a accommodated in the boot mounting groove 16 is tightened and a tightening force is applied over the entire circumference in the circumferential direction, the projecting portion 21 becomes a high compression portion having a larger compressibility in the radial direction than in other places. This increases the contact surface pressure between the inner peripheral surface (convex curved surface 12a) of the thick portion 18a and the outer peripheral surface 2a of the opening of the outer joint member 2 on the inner diameter side of the protruding portion 21, and is the same as that of the thin portion 18b. A certain contact surface pressure can be secured. Therefore, the contact surface pressure between the inner peripheral surface 10 of the large-diameter mounting portion 9a and the outer peripheral surface 2a of the opening of the outer joint member 2 can be made uniform over the entire circumference, and the boot 9 and the outer joint member 2 The sealing performance can be improved. The cross-sectional shape of the protruding portion 21 can be any shape as long as the thick portion 18a is thicker than the conventional product, and is not limited to the illustrated cross-sectional arc shape.

  In the above embodiment, the case where the protruding portion 21 is formed on the outer peripheral surface of the large-diameter mounting portion 9a of the boot 9 is illustrated, but the same function and effect are thick as shown in FIGS. Of the inner peripheral surface (convex curved surface 12a) of the portion 18a, it can also be obtained by forming the protruding portion 22 on the inner diameter side of the boot band 13a (inner diameter side of the band mounting groove 16) by build-up (FIG. 5). The broken line in FIG. 7 represents the shape of the inner peripheral surface of the thick portion 18a in the conventional product). In this case, the inner peripheral surface of the large-diameter mounting portion 9a has a shape corresponding to the outer peripheral surface 2a of the outer joint member 2 except for the protruding portion 22, and a concave corresponding to the convex curved surface 11b of the outer peripheral surface 2a of the opening. It has the curved surface 12b and the convex curved surface 12a corresponding to the concave curved surface 11a of the opening outer peripheral surface 2a. In a state in which the large-diameter mounting portion 9a is fitted to the outer peripheral surface 2a of the opening of the outer joint member 2 (a state before tightening by the boot band 13a), the tightening allowance at the protruding portion 22 is larger than the other portions.

  FIG. 5 shows an example in which the protruding portion 22 is formed with a cylindrical surface having a smaller radius of curvature than the conventional product, which is built up on the inner peripheral surface (convex curved surface 12a) of the thick portion 18a, and FIG. 7 is formed on the circumferential surface (convex curved surface 12a), and the protruding portion 22 is formed with a cylindrical surface having a larger radius of curvature than that of the conventional product. FIG. 7 shows the inner circumferential surface of the thick portion 18a on both sides in the circumferential direction 12a. The protruding portion 22 is formed by piling up. In any of the protrusions 22, after tightening with the boot band 13 a, the contact surface pressure between the inner peripheral surface of the protrusion 22 and the outer peripheral surface 2 a of the opening of the outer joint member 2 increases. A certain contact surface pressure can be secured. Therefore, the contact surface pressure can be made uniform over the entire circumference, and the sealing performance between the boot 9 and the outer joint member 2 can be improved.

FIG. 3 shows a modification of the large diameter attachment portion 9a. This modified example is different from FIG. 2B in that the protruding portion 21 is arranged on the outer peripheral surface of the large-diameter mounting portion 9a and at the boundary between the thick portion 18a and the thin portion 18b. Specifically, the projecting portion 21 includes a circumferential end of the convex curved surface 12a on the inner circumference of the thick portion 18a and a concave curved surface 12b of the thin portion 18b adjacent thereto on the outer peripheral surface of the band mounting groove 16. It is arranged on a radial line P ₂ passing through the boundary corner 20.

  By providing the projecting portion 21 having such a configuration, after the boot band 13a is tightened, the projecting portion 21 becomes a high compression portion having a large compressibility in the radial direction. Therefore, the contact surface pressure on the inner diameter side of the protruding portion 21 also increases. Thus, when the large-diameter mounting portion 9a of the boot 9 is fitted to the opening outer peripheral surface 2a of the outer joint member 2, even if a slight phase shift occurs in the circumferential direction, It is possible to increase the contact surface pressure between the peripheral boundary corner portion 20 and the outer peripheral surface 2a of the opening of the outer joint member 2, and to prevent the generation of a gap between them. Therefore, the contact surface pressure can be made uniform over the entire circumference, and the sealing performance between the boot 9 and the outer joint member 2 can be improved.

  FIG. 4 shows another modification of the large-diameter mounting portion 9a. The large-diameter attachment portion 9a is different from the large-diameter attachment portion 9a shown in FIG. 2B in that a hard member M that is harder than the material of the boot 9 is disposed in the thick portion 18a. The material of the hard member M should just be harder than the material of the boot 9, for example, a metal, resin, etc. are mentioned. By boot-molding the hard member M as an insert part with resin or the like, the boot 9 integrated with the hard member M can be manufactured as shown in the figure.

  By disposing the hard member M in the thick portion 18a in this way, the thickness of the boot material in the thick portion 18a can be reduced by the amount of the hard member M present. Therefore, it is possible to increase the compression ratio of the thick portion 18a after tightening the boot band 13a and further increase the contact surface pressure between the inner periphery of the thick portion 18a and the outer peripheral surface 2a of the opening of the outer joint member 2. The sealing performance between the boot 9 and the outer joint member 2 can be further improved.

  In the embodiment shown in FIG. 4, the hard member M is embedded in the thick portion 18 a, and therefore, there is an advantage that the hard member M hardly deteriorates over time. If the deterioration over time does not become a problem, the hard member M may be disposed on the outer periphery of the thick portion 18a. Further, similarly to FIGS. 5 to 7, in the configuration in which the protruding portion 21 is formed on the inner peripheral surface of the thick portion 18a, the hard member M may be disposed on the thick portion 18a. In the present embodiment, the cross-sectional shape of the hard member M is an ellipse that follows the inner peripheral surface and the outer peripheral surface shape of the thick portion 18a, but the shape is arbitrary.

  In the above embodiment, the boot 9 used for the tripod type constant velocity universal joint 1 is illustrated, but the present invention is not limited to this, and the other has the non-round type outer joint member 2. It can also be applied to the constant velocity universal joint boot 9 of the type. As an example, FIG. 8 shows a Rzeppa constant velocity universal joint and a boot used therefor.

  The Rzeppa type joint 1 ′ shown in FIG. 8 is a kind of fixed type constant velocity universal joint in which plunging of the outer joint member 2 and the inner joint member 6 is not allowed. The Rzeppa-type joint 1 'includes an outer joint member 2, an inner joint member 6, a ball 23 as a torque transmission element, and a cage 24 as main components. The Rzeppa type joint 1 ′ includes those having six balls 23 and those having eight balls 23.

  In the outer joint member 2, track grooves 5 having a circular cross section in the radial direction are formed at a plurality of locations (6 locations or 8 locations) in the circumferential direction on the inner peripheral surface thereof. The inner joint member 6 is formed with track grooves 6a having a circular cross section in the radial direction at a plurality of locations in the circumferential direction on the outer peripheral surface. The balls 23 are arranged in a ball track formed by the track grooves 5 of the outer joint member 2 and the track grooves 6a of the inner joint member 6, and are held by the cage 24 at equal intervals in the circumferential direction.

  The outer joint member 2 is a non-circular type in which the outer diameter side of the region between the track grooves in the cylindrical outer peripheral surface is gradually increased. The inner peripheral surface of the large-diameter mounting portion 9a of the boot 9 fitted to the outer peripheral surface 2a of the opening of the outer joint member 2 is similar to the outer joint of the boot 9 for the tripod type constant velocity universal joint shown in FIG. The member 2 has a shape corresponding to the shape of the outer peripheral surface 2a of the opening. As a result, the large-diameter mounting portion 9a has an outer area between the track grooves of the outer joint member 2 as shown in FIGS. 9 (A), 9 (B), 10 (A), and 10 (B). Thick portions 18a formed on the radial side and thin portions 18b formed on the outer diameter side of the track groove 5 are alternately formed in the circumferential direction. 9A and 9B show a boot 9 used for a constant velocity universal joint that uses six balls, and FIGS. 10A and 10B use eight balls. The boot 9 used for a constant velocity universal joint is represented.

  Among these, FIG. 9 (A) and FIG. 10 (A) are the examples which provided the protrusion part 21 in the outer peripheral surface of the thick part 18a similarly to embodiment shown to FIG. 2 (B), and FIG. B) and FIG. 10B are examples in which the protruding portion 21 is provided at the boundary between the thick portion 18a and the thin portion 18b, as in the embodiment shown in FIG. Although illustration is omitted, in each of the embodiments of FIGS. 9A, 9B and 10A, 10B, the inner periphery of the large-diameter mounting portion 9a is the same as in the embodiments of FIGS. The protruding portion 22 may be provided (the protruding portion 22 may be provided at the boundary between the thick portion 18a and the thin portion 18b). Alternatively, similarly to the embodiment shown in FIG. 4, the reinforcing member M may be disposed on the thick portion 18a (the reinforcing member M may be disposed on the boundary portion between the thick portion 18a and the thin portion 18b). . The operational effects obtained by these configurations are the same as the operational effects described in the embodiments shown in FIGS.

  In the above description, the boots used for the tripod type constant velocity universal joint and the Rzeppa type constant velocity universal joint are exemplified. However, the constant velocity universal joint boot of the present invention is not limited to the above-illustrated constant velocity universal joints, and other types of constant velocity universal joints such as a double offset type constant velocity universal joint and an undercut free type constant velocity universal joint. It can also be widely applied as boots used in. In FIG. 1, the tripod type constant velocity universal joint is exemplified by a configuration in which one roller is externally fitted to the journal 7. However, as the tripod type constant velocity universal joint, the roller is a double roller composed of an inner roller and an outer roller. There is also a type in which the outer roller is swingable with respect to the journal 7 of the inner joint member 6 with a structure. The present invention can be similarly applied to this type of tripod type constant velocity universal joint boot.

1 Tripod type constant velocity universal joint 1 'Rzeppa type joint (constant velocity universal joint)
2 outer joint member 2a outer peripheral surface 5 track groove 6 inner joint member 8 roller (torque transmission element)
9 Boots for constant velocity universal joint 9a Large-diameter mounting portion 10 Inner peripheral surface 13a Boot band 18a Thick portion 18b Thin portion 21, 22 Protruding portion 23 Ball (torque transmission element)
M Hard member R Track groove area

Claims (12)

A large-diameter mounting part fitted to the outer peripheral surface of the opening of the outer joint member of the constant velocity universal joint is provided, and a thick-walled part and a thin-walled part are provided alternately in the circumferential direction on the large-diameter mounting part. The inner peripheral surface of the outer joint member has a shape corresponding to the shape of the outer peripheral surface of the opening formed in a non-circular cross section of the outer joint member, and the large-diameter mounting portion is the outer peripheral surface of the opening of the outer joint member by the tightening force from the boot band. In a constant velocity universal joint boot fixed to
A boot for a constant velocity universal joint, wherein an inner diameter side of a boot band is formed in a non-circular cross section in an outer peripheral surface of a large-diameter mounting portion.   The constant velocity universal joint boot according to claim 1, wherein the boot is formed in a non-circular shape in cross section by a protrusion provided on the inner diameter side of the boot band. A large-diameter mounting part fitted to the outer peripheral surface of the opening of the outer joint member of the constant velocity universal joint is provided, and a thick-walled part and a thin-walled part are provided alternately in the circumferential direction on the large-diameter mounting part. The inner peripheral surface of the outer joint member has a shape corresponding to the shape of the outer peripheral surface of the opening formed in a non-circular cross section of the outer joint member, and the large-diameter mounting portion is the outer peripheral surface of the opening of the outer joint member by the tightening force from the boot band. In a constant velocity universal joint boot fixed to
A boot for a constant velocity universal joint, characterized in that a protruding portion is provided on the inner diameter side of the boot band on the inner peripheral surface of the large-diameter mounting portion.   The boot for a constant velocity universal joint according to claim 2 or 3, wherein the protruding portion is formed in a thick portion.   The constant velocity universal joint boot according to claim 2 or 3, wherein the protruding portion is formed at a boundary portion between the thick portion and the thin portion.   The constant velocity universal joint boot according to any one of claims 1 to 5, wherein a hard member harder than the boot material is disposed in the thick portion.   The constant velocity universal joint boot according to claim 6, wherein a hard member is embedded in the thick portion.   The boot according to any one of claims 1 to 5, an opening at one end in the axial direction, and a track groove and a region between the track grooves located on the inner diameter side of the track groove on the inner periphery in the circumferential direction. The outer joint member is formed alternately and the outer peripheral surface is thinned on the outer diameter side of the region between the track grooves, the inner joint member disposed inside the outer joint member, and the inner joint member and the outer joint member. A constant velocity universal joint comprising: a torque transmission element that transmits torque in a step; and a boot band that is attached to the outer peripheral surface of the large-diameter mounting portion of the boot and applies a tightening force in the inner diameter direction to the large-diameter mounting portion.   The constant velocity universal joint according to claim 8, further comprising a roller as a torque transmission element.   The constant velocity universal joint according to claim 8, wherein the torque transmitting element has a ball.   The constant velocity universal joint according to claim 10, comprising six balls.   The constant velocity universal joint according to claim 10, comprising eight balls.

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