Method for fixing boots to constant velocity universal joints

Abstract

To secure sealability in a fixing part, when a large-diameter end part of a boot having thin parts and thick parts arranged alternately in a circumferential direction is fixed to an outer periphery of an outside joint member.SOLUTION: A method for fixing a boot of a constant velocity universal joint has a step of fitting a boot 20 to the outer periphery of an outside joint member 2, a step of winding a boot band 100 around the outer periphery of the boot 20, and a step of contracting the boot band 100 to tighten the boot 20. A portion (ear part 111) of the boot band 100 to which inward pressing force is applied when the diameter of the boot band 100 is contracted is arranged within a circumferential region R of a thin part 21S of the boot 20.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for fixing a boot to a constant velocity universal joint. [Background technology]

[0002] A constant velocity universal joint transmits rotational power at a constant speed between two shafts, a driving side and a driven side, and is incorporated in the power transmission system of, for example, automobiles and various industrial machines. The constant velocity universal joint includes a cup-shaped outer joint member and an inner joint member disposed in the internal space of the outer joint member, and is usually used with the internal space of the outer joint member filled with a lubricant such as grease. To prevent the lubricant from leaking to the outside and foreign matter from entering the inside of the joint, a cylindrical boot made of an elastic material such as rubber or resin is provided at the opening of the outer joint member. One end of the boot is fixed to the outer joint member, and the other end of the boot is fixed to a shaft connected to the inner joint member.

[0003] The cylindrical portions provided at one end and the other end of the boot are generally fixed to the mounting object by fastening their outer circumferential surfaces with fastening members called boot bands. Known boot bands include (1) Omega type (see Patent Document 1), (2) Low profile type (see Patent Document 2), and (3) One-touch type (see Patent Document 3). Each boot band will be described in detail below with reference to the drawings.

[0004] (1) Omega type boot band (see Figures 10-13) The omega-type boot band 100 is made of a metal strip member 101. An end region 110 on one side in the longitudinal direction of the strip member 101 (the right side in Figs. 10 and 11) is formed with an ear 111, engagement holes 112, 113, 114, and a recess 115. The ear 111 is formed by bending a part of the strip member 101, and has an Ω shape in a side view having a pair of legs 111a spaced apart in the circumferential direction and a top 111b connecting the ends of the pair of legs 111a. The recess 115 is formed, for example, by forming a pair of slits extending in the longitudinal direction in the strip member 101, and raising the space between the slits (the remaining part) into a convex shape. An end region 120 on the other side in the longitudinal direction (the left side in FIGS. 10 and 11) of the band plate member 101 is provided with protrusions 121, 122, 123 and an extension portion 124 that extends in the longitudinal direction and has a constant width.

[0005] When tightening the boot band 100, as shown in Fig. 12, the boot band 100 is made into a ring shape, and the two end regions 110 and 120 are overlapped, and the projections 121, 122, and 123 of the other end region 120 are fitted into the engagement holes 112, 113, and 114 of one end region 110, respectively (they are engaged in the longitudinal direction of the boot band 100). Also, the extension portion 124 of the other end region 120 enters the recess 115 of one end region 110, and engages in the width direction (axial direction of the outer joint member 2). In this state, as shown in Fig. 13, the ear portion 111 is crimped from both sides in the circumferential direction with a tool T1 to plastically deform it. As a result, the ring-shaped strip member 101 (boot band 100) is reduced in diameter, and a tightening force in the diameter reduction direction is applied to the boot arranged on the radial inside thereof, and as a result, the boot 20 is fixed to the outer joint member.

[0006] (2) Low-profile type boot band (see Figures 14 to 17) The low-profile type boot band 200 is made of a metal strip member 201. A first tool claw 211, engagement holes 212, 213, and a recess 214 are formed in an end region 210 on one side of the longitudinal direction of the strip member 201 (the right side in Figs. 14 and 15). The recess 214 is formed, for example, by forming a pair of slits extending in the longitudinal direction in the strip member 201 and raising the space between the slits (the remaining portion) into a convex shape. A second tool claw 221, a temporary fixing hook 222, engagement claws 223, 224, and an extension portion 225 with a constant width that extends in the longitudinal direction are formed in an end region 220 on the other side of the longitudinal direction of the strip member 201 (the left side in Figs. 14 and 15).

[0007] When tightening the boot band 200, as shown in Fig. 16, the boot band 200 is made into a ring shape, the end regions 210, 220 are overlapped, and the second tool claw 221 and the temporary fixing hook 222 of one end region 220 are inserted into the engagement hole 212 of the other end region 210. In this state, as shown in Fig. 17, the tool T2 is hooked on the first tool claw 211 and the second tool claw 221, and the tool claws 211, 221 are pulled together so that the distance between them is shortened, thereby reducing the diameter of the ring-shaped boot band 200. As a result, the engagement claws 223, 224 enter and engage with the engagement holes 212, 213, respectively, and the reduced diameter state is maintained while the boot band is tightened.

[0008] (3) One-touch type boot band (see Figures 18 and 19) 18, a one-touch type boot band 300 has a ring-shaped band body 301 formed by joining the inner surfaces of both ends of a metal strip together, and an arc-shaped lever 302 joined to the outer surface of one end of the band body 301. The band body 301 is provided with a stopper 303 that holds the lever 302 after it has been folded back. The stopper 303 is formed integrally with the band body 301 or separately, and has a pair of side portions that rise outward from both ends of the band body 301 in the width direction.

[0009] When fastening the boot band 300, with the fastened member placed on the inner circumference of the ring-shaped band body 301, the end of the lever 302 is folded back as a fulcrum, thereby reducing the diameter of the band body 301 and tightening and fixing the fastened member (see FIG. 19). The folded back lever 302 is placed over the band body 301 and is fitted and held between a pair of side portions of the stopper 303. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2018-84306 A [Patent Document 2] Patent No. 4403728 [Patent Document 3] JP 2020-41661 A Summary of the Invention [Problem to be solved by the invention]

[0011] In a tripod-type constant velocity universal joint, which is a type of sliding type constant velocity universal joint, as shown in Fig. 20, three track grooves 5 extending in the axial direction are formed at multiple locations in the circumferential direction on the inner circumferential surface of the outer joint member 2, and the outer circumferential surface of the outer joint member 2 has a non-circular shape with recesses 2a between adjacent track grooves 5. The inner circumferential surface of a large diameter end portion 21 of a boot 20 that fits into this outer joint member 2 has a non-circular shape following the outer circumferential surface of the outer joint member 2. As a result, thick-walled portions 21L and thin-walled portions 21S are formed alternately in the circumferential direction on the large diameter end portion 21 of the boot 20.

[0012] For example, when the outer joint member 2 and the boot 20 of the tripod type constant velocity universal joint are fixed using the (1) omega type boot band 100, as shown in FIG. 21, the ears 111 are crimped from both sides in the circumferential direction with a tool T1. At this time, the ears 111 are crimped while the tool T1 is pressed inwardly so that the tool T1 does not come off the ears 111. Specifically, the tool T1 is brought into contact with the inner diameter end of each leg 111a of the ears 111 (the boundary between the ears 111 and the areas adjacent to them on both sides in the circumferential direction), and the pair of legs 111a are pressed with a force F in a direction inclined toward the inner diameter side toward the sides where they approach each other (see the arrows in the figure). The boot 20 is compressed in the radial direction by the radial component force (the pressing force toward the inner diameter) of the pressing force F by the tool T1 (in FIG. 21, the area of ​​the outer circumferential surface of the boot 20 that is deformed by the pressing force of the tool T1 is shown as a flat surface). If the boot and the outer joint member are fixed together in a state in which a portion of the boot in the circumferential direction is compressively deformed in this manner, there is a risk that sealing performance will deteriorate in the deformed portion of the boot.

[0013] When the outer joint member of a tripod type constant velocity universal joint and a boot are fixed using the low-profile type boot band 200 described above in (2), the tool claws 211, 221 are tightened while pressing the tool against the boot band 200 in the inward radial direction. This can cause the same problems as described above.

[0014] When the one-touch type boot band 300 described above in (3) is used to fix the outer joint member of a tripod type constant velocity universal joint to the boot, a pressing force toward the inner diameter is generated at the end of the lever 302, which serves as a fulcrum when the lever 302 is folded back. This can cause the same problems as described above.

[0015] Therefore, an object of the present invention is to ensure sealing at the fixing portion when using a boot band to fix a cylindrical boot having thin and thick portions alternating in the circumferential direction to the outer periphery of an outer joint member. [Means for solving the problem]

[0016] The present invention, which has been made to solve the above problems, provides a method for fixing a large diameter end portion of a cylindrical boot, the large diameter end portion having thin-walled portions and thick-walled portions alternately in a circumferential direction, to an outer periphery of an outer joint member by using a boot band, the method comprising the steps of: the step of fitting the large diameter end of the boot onto an outer periphery of the outer joint member, the step of wrapping the boot band around the outer periphery of the large diameter end of the boot, and the step of reducing the diameter of the boot band to fasten the large diameter end of the boot, The present invention is characterized in that a portion of the boot band to which a pressing force in the inward direction is applied when the boot band is reduced in diameter is disposed within a circumferential region of a thin-walled portion at a large diameter end of the boot.

[0017] Thus, the present invention is characterized in that the boot band and the outer joint member are aligned in the circumferential direction before the boot band is tightened. That is, when the boot band is tightened by reducing its diameter with a tool or lever, the portion of the boot band to which a pressing force in the inward direction is applied (the portion that the tool abuts against or the fulcrum of the lever) is disposed within the circumferential region of the thin-walled portion of the large diameter end of the boot. As a result, the pressing force in the inward direction is applied to the thin-walled portion of the boot, so that the amount of deformation of the boot in the radial direction can be suppressed and a decrease in sealing performance due to the deformation of the boot can be prevented.

[0018] As the boot band, for example, a so-called omega-type boot band can be used, which has an Ω-shaped ear portion in a portion in the longitudinal direction and is tightened from both circumferential sides with a tool to reduce the diameter of the boot band and tighten the boot. In this case, when tightening the boot band, by arranging the ear portion of the boot band within the circumferential region of the thin-walled portion of the large diameter end of the boot, deformation of the boot due to a pressing force toward the inner diameter can be suppressed.

[0019] As the boot band, for example, a so-called low-profile type boot band can be used, which has a pair of tool jaws spaced apart in the longitudinal direction and tightens the boot by reducing the diameter of the boot band by bringing the pair of tool jaws closer to each other with a tool. In this case, when tightening the boot band, deformation of the boot due to a pressing force toward the inner diameter can be suppressed by arranging the pair of tool jaws of the boot band within the circumferential region of the thin-walled part of the large diameter end of the boot.

[0020] The boot band may be a so-called one-touch type boot band having a band body formed by joining both ends of a strip-shaped member into a ring shape, and an arc-shaped lever fixed to the band body with one end in contact with the band body and the other end spaced apart from the band body, in which the boot band is reduced in diameter by folding back the lever using one end of the lever as a fulcrum to tighten the boot. In this case, by locating one end of the lever, which serves as a fulcrum when folding back the lever to tighten the boot band, within the circumferential region of the thin-walled part at the large diameter end of the boot, deformation of the boot due to the pressing force acting on the fulcrum toward the inner diameter can be suppressed.

[0021] In the above boot fixing method, it is preferable that the outer joint member is supported from below by a support member, and the large diameter end of the boot is fastened with a boot band in a state in which a convex surface on an upper end of the support member is fitted into a concave surface on the outer circumferential surface of the outer joint member. This makes it possible to stably support the outer joint member and facilitates the operation of setting the outer joint member on the support member. Effect of the Invention

[0022] As described above, according to the present invention, deformation of the boot caused by the pressing force in the inward direction when tightening the boot band is suppressed, thereby preventing deterioration of sealing performance caused by deformation of the boot. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 is an axial cross-sectional view of a tripod type constant velocity universal joint. [Diagram 2]2 is a cross-sectional view of the tripod type constant velocity universal joint taken along a line perpendicular to the axis (a cross-sectional view taken along the line YY in FIG. 1). [Diagram 3] 1 is a cross-sectional view taken along a direction perpendicular to the axis of a tripod-type constant velocity universal joint having an omega-type boot band, showing the state before the boot band is tightened. FIG. [Figure 4] FIG. 4 is a cross-sectional view showing a state after the boot band in FIG. 3 has been fastened. [Diagram 5] 1 is a cross-sectional view taken along a direction perpendicular to an axis of a tripod-type constant velocity universal joint having a low-profile type boot band, showing a state before the boot band is tightened. FIG. [Figure 6] FIG. 6 is a cross-sectional view showing a state in which the boot band of FIG. 5 is being fastened. [Figure 7] FIG. 6 is a cross-sectional view showing a state after the boot band in FIG. 5 has been fastened. [Figure 8] 1 is a cross-sectional view perpendicular to the axis of a tripod-type constant velocity universal joint having a one-touch type boot band, showing the state before the boot band is tightened. FIG. [Figure 9] FIG. 9 is a cross-sectional view showing a state after the boot band in FIG. 8 has been fastened. [Figure 10] FIG. 2 is a side view of an omega type boot band. [Figure 11] FIG. 11 is a plan view of the boot band of FIG. 10. [Figure 12] FIG. 11 is a side view of the boot band of FIG. 10 in a rolled state prior to tightening. [Figure 13] FIG. 13 is a side view showing the boot band of FIG. 12 in a state after it has been fastened. [Figure 14] FIG. 2 is a side view of a low-profile type boot band. [Figure 15] FIG. 15 is a plan view of the boot band of FIG. 14. [Figure 16] FIG. 15 is a side view of the boot band of FIG. 14 in a rolled state prior to tightening. [Figure 17] FIG. 17 is a side view showing the boot band of FIG. 16 in a state after it has been fastened. [Figure 18]FIG. 2 is a side view of a one-touch type boot band, showing the state before being fastened. [Figure 19] FIG. 19 is a side view showing the boot band of FIG. 18 in a state after it has been fastened. [Figure 20] 11 is a cross-sectional view taken in a direction perpendicular to the axis, illustrating a state in which a boot and an outer joint member are fixed together by the boot band of FIG. 10. FIG. [Figure 21] FIG. 21 is an enlarged view of the vicinity of the ear portion in FIG. 20. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0025] As shown in Figures 1 and 2, a tripod type constant velocity universal joint 1 according to this embodiment includes a cup-shaped outer joint member 2, a tripod member 3 as an inner joint member, and three rollers 4 as rolling elements.

[0026] Three track grooves 5 are formed at equal intervals in the circumferential direction on the inner peripheral surface of the outer joint member 2. Each track groove 5 has a pair of roller guideways 5a facing each other in the circumferential direction. Each roller guideway 5a extends linearly along the axial direction of the outer joint member 2 and is formed in an arc shape in a cross section perpendicular to the axial direction.

[0027] The tripod member 3 has a cylindrical boss portion 6 and three trunnions 7 protruding radially from the boss portion 6. An end of a shaft 10 is coupled to a central hole 6a of the boss portion 6 by spline fitting. The shaft 10 is prevented from coming off from the boss portion 6 by a retaining ring 11. A roller 4 is rotatably mounted on each trunnion 7 via a plurality of needle rollers 8. The rollers 4 are disposed one by one in each track groove 5 of the outer joint member 2, and the rollers 4 move along the roller guide surfaces 5a of the track grooves 5, so that the tripod member 3 can transmit rotational torque to the outer joint member 2 while allowing angular displacement and axial displacement.

[0028] A cylindrical boot 20 is attached between the outer joint member 2 and the shaft 10 to prevent foreign matter from entering the joint and to prevent leakage of grease sealed in the joint. The boot 20 is composed of a large diameter end 21 attached to the outer circumferential surface of the outer joint member 2, a small diameter end 22 attached to the outer circumferential surface of the shaft 10, and a bellows portion 23 connecting the large diameter end 21 and the small diameter end 22. The large diameter end 21 and the small diameter end 22 of the boot 20 are fastened and fixed to the outer circumferential surface of the outer joint member 2 and the outer circumferential surface of the shaft 10 by a boot band. As the boot band attached to the large diameter end 21 of the boot 20, for example, an omega type boot band 100 shown in Figs. 10 to 13 can be used. The details of the boot band 100 are as described above. The boot band 100' attached to the small diameter end 22 of the boot 20 has a basically similar configuration to the above-mentioned boot band 100, except for the longitudinal dimension (circumferential length).

[0029] As shown in FIG. 2, the outer circumferential surface of the outer joint member 2 is thinned by forming recesses 2a between adjacent track grooves 5 in the circumferential direction. The inner circumferential surface of the large diameter end 21 of the boot 20 is formed with protrusions 21a at positions corresponding to the recesses 2a on the outer circumferential surface of the outer joint member 2. As a result, in the circumferential region of the protrusions 21a of the large diameter end 21 of the boot 20, a thick portion 21L having a relatively thick radial thickness is formed, and in the circumferential region between the protrusions 21a, a thin portion 21S having a relatively thin radial thickness is formed. In order to improve the sealing performance between the boot 20 and the outer joint member 2, a circumferential groove 9 into which the boot 20 bites is formed in the region (large diameter portion) of the outer circumferential surface of the outer joint member 2 except for the recesses 2a. When the boot 20 is fastened by the boot band 100, the entire circumferential region of the inner circumferential surface of the large diameter end 21 of the boot 20 contacts the outer circumferential surface of the outer joint member 2.

[0030] A fixing method of the present invention is applied to fixing the boot 20 and the outer joint member 2 by the boot band 100. The steps of the fixing method of the boot 20 will be described below.

[0031] First, with the shaft 10 inserted into the inner periphery of the boot 20, an assembly in which the tripod members 3 and the rollers 4 are integrated is fixed to the end of the shaft 10. After that, the tripod members 3 and the rollers 4 are disposed on the inner periphery of the outer joint member 2 while the rollers 4 are fitted into the track grooves 5 of the outer joint member 2. Then, the large diameter end 21 of the boot 20 is fitted into the outer periphery of the outer joint member 2. At this time, as shown in FIG. 2, the convex portion 21a on the inner periphery of the large diameter end 21 of the boot 20 is aligned with the concave portion 2a on the outer periphery of the outer joint member 2, and the large diameter end 21 of the boot 20 is fitted into the outer periphery of the open end of the outer joint member 2.

[0032] Next, as shown in FIG. 3, in a state where the outer joint member 2 is supported from below by the support member 30 (see FIG. 1), the boot band 100 is wound around the outer periphery of the large diameter end portion 21 of the boot 20. Specifically, the band plate member 101 of the boot band 100 is rolled into a ring shape, and one end region 110 in the longitudinal direction of the band plate member 101 is overlapped on the outer diameter side of the other end region 120 in the longitudinal direction of the band plate member 101. At this time, the projections 121, 122, 123 provided on the end region 120 on the inner diameter side enter into the engagement holes 112, 113, 114 provided on the end region 110 on the outer diameter side, and these engage with each other in the longitudinal direction. Also, the extension portion 124 provided on the end region 120 on the inner diameter side enters into the recess 115 provided on the end region 110 on the outer diameter side, and these engage with each other in the width direction (axial direction of the outer joint member 2). 3 and 4, the internal parts (the tripod member 3, the rollers 4, etc.) and the shaft 10 of the constant velocity universal joint 1 are omitted (the same applies to FIGS. 5 to 9 described later).

[0033] At this time, the boot band 100 and the boot 20 are aligned in the circumferential direction so that the entire ear 111 of the boot band 100 is disposed within the circumferential region R of the thin-walled portion 21S of the boot 20. In the illustrated example, the ear 111 is disposed at approximately the center of the circumferential region R of the thin-walled portion 21S of the boot 20 (at a position overlapping with the circumferential center line C of the thin-walled portion 21S). At this time, since the thick-walled portion 21L of the boot 20 is disposed at the lower end, the recess 2a of the outer circumferential surface of the outer joint member 2 that fits therewith is disposed at the lower end. The outer joint member 2 can be stably supported by fitting a convex surface provided at the upper end of the support member 30 into this recess 2a. Moreover, when the outer joint member 2 is placed on the support member 30, the concave portion of the outer joint member 2 is fitted while being guided by the convex surface of the support member 30, and the outer joint member 2 is positioned at a predetermined phase (a state in which the circumferential center of any one of the track grooves 5 is disposed directly above the support member 30). In this case, the worker does not need to be too concerned about the positional accuracy of the outer joint member 2 relative to the support member 30, and the outer joint member 2 is naturally positioned simply by placing the outer joint member 2 on the support member 30, which facilitates the work. Moreover, since the positional accuracy required when setting the outer joint member 2 on the support member 30 is relaxed, this work can also be performed by an automated machine.

[0034] In this state, the ears 111 are crimped from both circumferential sides with a tool T1 to reduce the diameter of the band plate member 101 of the boot band 100 rolled into a ring shape (see FIG. 4). Specifically, the pair of legs 111a of the ears 111 are pressed toward each other with the tool T1 to deform the pair of legs 111a. As a result, the large diameter end 21 of the boot 20 is clamped from the outer diameter by the boot band 100, and the boot 20 is fixed to the outer joint member 2 by this clamping force.

[0035] When the ears 111 are tightened with the tool T1 in this manner, a pressing force in the inward direction by the tool T1 is applied to the boot 20. At this time, since the ears 111 are disposed within the circumferential region R of the thin-walled portion 21S of the boot 20 as described above, the pressing force in the inward direction by the tool T1 is applied to the thin-walled portion 21S of the boot 20. Therefore, the amount of deformation (amount of compression) of the boot 20 can be reduced compared to the case where the thick-walled portion 21L of the boot 20 is pressed inward as shown in FIG. 21. This makes it possible to prevent a decrease in the sealing performance between the boot 20 and the outer joint member 2 caused by deformation of the boot 20.

[0036] The present invention is not limited to the above embodiment. Other embodiments of the present invention will be described below, but redundant description of the same points as the above embodiment will be omitted.

[0037] The boot band for fixing the boot 20 and the outer joint member 2 is not limited to the above, and for example, a low-profile type boot band 200 shown in Figs. 14 to 17 can be used. In this case, as shown in Fig. 5, the boot band 200 is wound around the outer periphery of the large diameter end 21 of the boot 20 while the outer joint member 2 is supported from below by the support member 30. Specifically, the band plate member 201 of the boot band 200 is rolled into a ring shape, and one end region 210 in the longitudinal direction of the band plate member 201 is overlapped on the outer diameter side of the end region 220 in the longitudinal direction of the band plate member 201. At this time, the second tool claw 221 and the temporary fixing hook 222 provided in the end region 220 on the inner diameter side enter the engagement hole 212 provided in the end region 210 on the outer diameter side, and the engagement hole 212 and the temporary fixing hook 222 are engaged in the longitudinal direction. Further, the extension portion 225 provided on the inner diameter side end region 220 fits into the recess 214 provided on the outer diameter side end region 210, and these engage in the width direction (axial direction of the outer joint member 2).

[0038] In this state in which the boot band 200 is temporarily fixed by engaging the engagement holes 212 with the temporary fixing hooks 222, the boot band 200 and the boot 20 are circumferentially aligned so that the first tool claw 211 and the second tool claw 221 of the boot band 200 are disposed within the circumferential region R of the thin-walled portion 21S of the boot 20. In the illustrated example, the circumferential position of the boot band 200 relative to the boot 20 is adjusted so that the circumferential center line C of the thin-walled portion 21S of the boot 20 is disposed between the two tool claws 211, 221 in the circumferential direction.

[0039] In this state, the tool T2 is engaged with the first tool claw 211 and the second tool claw 221 from both circumferential sides, and the two tool claws 211, 221 are brought closer to each other, thereby reducing the diameter of the band plate member 201 of the boot band 200 rolled into a ring shape (see FIGS. 6 and 7). As a result, the large diameter end portion 21 of the boot 20 is tightened from the outer diameter by the boot band 200, and the boot 20 is fixed to the outer joint member 2 by this tightening force.

[0040] When the tool claws 211, 221 are moved closer to each other by the tool T2 in this manner, a pressing force in the inward direction by the tool T2 is applied to the boot 20. At this time, since both tool claws 211, 221 are disposed within the circumferential region R of the thin-walled portion 21S of the boot 20 as described above, the pressing force in the inward direction by the tool T2 is applied to the thin-walled portion 21S of the boot 20. Therefore, the amount of deformation (amount of compression) of the boot 20 can be suppressed compared to the case where the thick-walled portion 21L of the boot 20 is pressed inward. This makes it possible to prevent a decrease in the sealing performance between the boot 20 and the outer joint member 2 caused by the deformation of the boot 20.

[0041] The boot band for fixing the boot 20 and the outer joint member 2 is not limited to the above, and for example, a one-touch type boot band 300 shown in Figs. 18 and 19 can be used. In this case, as shown in Fig. 8, in a state where the outer joint member 2 is supported from below by the support member 30, the large diameter end portion 21 of the boot 20 is disposed on the inner circumference of the ring-shaped band body 301 of the boot band 300, so that the band body 301 of the boot band 300 is wound around the outer circumference of the boot 20. At this time, the boot band 300 and the boot 20 are aligned in the circumferential direction so that one end 302a (the end portion that serves as a fulcrum when folded back) of the lever 302 of the boot band 300 is disposed within the circumferential region R of the thin-walled portion 21S of the boot 20. In the illustrated example, one end 302a of the lever 302 is disposed on the circumferential center line C of the thin-walled portion 21S of the boot 20.

[0042] In this state, the lever 302 is folded back to reduce the diameter of the ring-shaped band body 301 (see FIG. 9). As a result, the large diameter end 21 of the boot 20 is tightened from the outer diameter by the boot band 300, and the boot 20 is fixed to the outer joint member 2 by this tightening force.

[0043] At this time, one end 302a of the lever 302, which serves as a fulcrum when folding back, presses the folded-back portion 301a of the band body 301 inwardly, so that a pressing force inwardly is applied to the boot 20. At this time, since the one end 302a of the lever 302 is disposed within the circumferential region R of the thin-walled portion 21S of the boot 20 as described above, the pressing force from the end 302a of the lever 302 is applied to the thin-walled portion 21S of the boot 20. Therefore, the deformation amount (compression amount) of the boot 20 can be suppressed compared to the case where the thick-walled portion 21L of the boot 20 is pressed inwardly. This makes it possible to prevent a decrease in the sealing performance between the boot 20 and the outer joint member 2 caused by the deformation of the boot 20. [Explanation of symbols]

[0044] 1 Tripod type constant velocity joint 2 Outer joint member 3 Tripod member (inner joint member) 5 Track groove 10 Shaft 20 Boots 21 Large diameter end 21L thick part 21S Thin wall part 22 Small diameter end 23 Bellows section 100 Boot band (Omega type) 111 Ears 200 Boot band (low profile type) 211, 221 Tool jaw 300 Boot band (one-touch type) 301 Band body 302 Lever F Pressure T1, T2 tools

Claims

1. A method for fixing a large diameter end portion of a cylindrical boot, the large diameter end portion having thin-walled portions and thick-walled portions alternately in a circumferential direction, to an outer periphery of an outer joint member by using a boot band, comprising the steps of: the step of fitting the large diameter end of the boot onto an outer periphery of the outer joint member, the step of wrapping the boot band around the outer periphery of the large diameter end of the boot, and the step of reducing the diameter of the boot band to fasten the large diameter end of the boot, a portion of the boot band to which a pressing force in an inward direction is applied when the boot band is reduced in diameter is disposed within a circumferential region of a thin-walled portion of a large diameter end of the boot; A method for fixing a boot of a constant velocity universal joint, comprising supporting the outer joint member from below with a support member, fitting a convex surface on an upper end of the support member into a concave surface on the outer peripheral surface of the outer joint member, and tightening a large diameter end of the boot with the boot band.

2. A method for fixing a large diameter end portion of a cylindrical boot, the large diameter end portion having thin-walled portions and thick-walled portions alternately in a circumferential direction, to an outer periphery of an outer joint member by using a boot band having an Ω-shaped ear portion in a part of the longitudinal direction, the method comprising the steps of: a first step of fitting a large diameter end portion of the boot onto an outer periphery of the outer joint member; a second step of wrapping the boot band around an outer periphery of the large diameter end of the boot; a third step of circumferentially aligning the boot band with the boot so that the ear is disposed within a circumferential region of a thin-walled portion of a large diameter end of the boot after the second step; and a fourth step of tightening the boot band by crimping the ears from both circumferential sides with the ears positioned within the circumferential region of the thin-walled portion of the large diameter end of the boot, thereby reducing the diameter of the boot band and tightening the large diameter end of the boot.

3. A method for fixing a large diameter end portion of a cylindrical boot, the large diameter end portion having thin-walled portions and thick-walled portions alternately in a circumferential direction, to an outer periphery of an outer joint member by using a boot band having a pair of tool jaws spaced apart in a longitudinal direction, the method comprising: the step of fitting the large diameter end of the boot onto an outer periphery of the outer joint member, the step of wrapping the boot band around the outer periphery of the large diameter end of the boot, and the step of reducing the diameter of the boot band by bringing the pair of tool claws closer to each other to tighten the large diameter end of the boot, A method for fixing the boot of a constant velocity universal joint, characterized in that, with the pair of tool claws positioned within the circumferential region of the thin-walled portion of the large diameter end of the boot, the pair of tool claws are brought closer to each other to reduce the diameter of the boot band.

4. A method for fixing a large diameter end portion of a cylindrical boot, the large diameter end portion having thin and thick portions alternately in a circumferential direction, to an outer periphery of an outer joint member by using a boot band having a band body formed into a ring shape by joining both ends of a strip-like member, and an arc-shaped lever fixed to the band body, comprising: the step of fitting the large diameter end of the boot onto an outer periphery of the outer joint member, the step of wrapping a band body of the boot band around the outer periphery of the large diameter end of the boot, and the step of folding back the lever using one end of the lever as a fulcrum to reduce the diameter of the band body and tighten the large diameter end of the boot, With one end of the lever disposed within the circumferential region of the thin-walled portion of the large-diameter end of the boot, the lever is folded back to reduce the diameter of the band body; A method for fixing a boot of a constant velocity universal joint, comprising supporting the outer joint member from below with a support member, fitting a convex surface on an upper end of the support member into a concave surface on the outer peripheral surface of the outer joint member, and tightening a large diameter end of the boot with the boot band.

5. A method for fixing a large diameter end portion of a cylindrical boot, the large diameter end portion having thin-walled portions and thick-walled portions alternately in a circumferential direction, to an outer periphery of an outer joint member by using a boot band having an Ω-shaped ear portion in a part of the longitudinal direction, the method comprising the steps of: the step of fitting the large diameter end of the boot onto an outer periphery of the outer joint member, the step of wrapping the boot band around the outer periphery of the large diameter end of the boot, and the step of tightening the large diameter end of the boot by reducing the diameter of the boot band by crimping the ears from both circumferential sides, With the ears disposed within the circumferential region of the thin-walled portion of the large diameter end of the boot, the ears are tightened to reduce the diameter of the boot band; A method for fixing a boot of a constant velocity universal joint, comprising supporting the outer joint member from below with a support member, fitting a convex surface on an upper end of the support member into a concave surface on the outer peripheral surface of the outer joint member, and tightening a large diameter end of the boot with the boot band.

6. A constant velocity universal joint comprising an outer joint member, an inner joint member disposed on an inner periphery of the outer joint member, a boot having a large diameter end attached to an outer periphery of the outer joint member, and a boot band fastening and fixing the large diameter end of the boot, The large diameter end of the boot has thin-walled portions and thick-walled portions alternately in a circumferential direction, the boot band having a pair of longitudinally spaced tool jaws; The pair of tool claws are brought closer to each other to reduce the diameter of the boot band, thereby tightening and fixing the boot. The pair of tool claws are disposed within a circumferential region of a thin-walled portion of a large diameter end of the boot.

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