JP2026007739A - Constant velocity joints and propeller shafts - Google Patents

Abstract

A constant velocity joint and a propeller shaft are provided that enable improved workability in assembling a boot member to the constant velocity joint.
[Solution] In the second constant velocity joint J2 used in a propeller shaft PS according to the present invention, the boot member 9 can be attached to the inner ring member 6 simply by engaging the sleeve portion 92 with the sleeve engaging portion 64 of the inner ring member 6. Therefore, unlike conventional constant velocity joints, it is not necessary to press-fit and fix the sleeve portion 92 of the boot member 9 into the inner ring member 6. This reduces the workload involved in attaching the boot member 9 to the inner ring member 6, and improves the ease of assembling the boot member 9 to the second constant velocity joint J2.
[Selected Figure] Figure 3

Description

The present invention relates to a constant velocity joint and a propeller shaft.

A known example of a conventional constant velocity joint is that described in Patent Document 1 below.

This constant velocity joint has an inner ring member that engages with a shaft member extending from the vehicle side so that it can rotate together with the shaft member; a cylindrical outer ring member that is arranged on the outer periphery of the inner ring member and has a bottom and is open at one axial end and closed at the other; multiple rolling elements that are arranged so that they can roll between the inner ring member and the outer ring member; and a cage that is arranged between the inner ring member and the outer ring member and that holds the rolling elements so that they can roll.

A boot member is provided between the inner and outer ring members to cover the opening of the outer ring member. This boot member has a cylindrical sleeve portion that is press-fitted into the inner ring member, an annular adapter portion that is crimped to the outer ring member, and a boot portion that connects the sleeve member and adapter member in a flexible manner.

Japanese Patent Application Laid-Open No. 2014-077476

However, in the conventional constant velocity joints described above, the sleeve is press-fit into the inner ring member. This means that the workload of assembling the boot member into the constant velocity joint is significant, and there is still room for improvement.

The present invention was devised in light of the technical issues with conventional power transmission shafts, and aims to provide a constant velocity joint and propeller shaft that can improve the ease of assembling a boot member to a constant velocity joint.

In one aspect of the present invention, the sleeve portion of the boot member is formed into a cylindrical shape from a metal member, extends toward the sleeve engagement portion of the inner ring member, and bends radially away from the rotation axis as it approaches the sleeve engagement portion, abutting and engaging the inner circumferential side of the sleeve engagement portion.

This invention improves the ease of assembling a boot member to a constant velocity joint.

FIG. 2 is a side view of a propeller shaft according to the present invention. 2 is an exploded view of a main part of the propeller shaft, in which the constant velocity joint, the boot member, and the shaft member shown in part A of FIG. 1 are disassembled in the axial direction. FIG. 2 is an enlarged view of a constant velocity joint according to the present invention, and is an enlarged view of a portion A in FIG. 1. 3 is an enlarged view of a main portion of the constant velocity joint shown in FIG. 2 with a boot member assembled thereto and before a shaft member is connected to an inner ring member. FIG. FIG. 4 is an enlarged view of part B in FIG. 3 . 1A and 1B are cross-sectional views of a constant velocity joint showing an assembly process of the constant velocity joint according to the present invention, in which FIG. 1A shows a state before the sleeve portion is assembled to the inner ring member, and FIG. 1B shows a state in which the sleeve portion is engaged with the inner ring member. 10A and 10B are cross-sectional views of a constant velocity joint illustrating the process of assembling a propeller shaft to the constant velocity joint according to the present invention, in which FIG. 10A illustrates the state immediately before inserting a shaft member into the sleeve portion, and FIG. 10B illustrates the state after inserting the shaft member into the inner ring member.

Embodiments of a constant velocity joint and a propeller shaft according to the present invention will be described in detail below with reference to the drawings. Note that in each of the following embodiments, the constant velocity joint and propeller shaft according to the present invention will be described as being applied to a propeller shaft for an automobile, as in the conventional art.

(Propeller shaft configuration)
Fig. 1 shows a side view of an automotive propeller shaft according to this embodiment, to which a constant velocity joint and a propeller shaft according to the present invention are applied. In the following description of the embodiment, for convenience, the left side of Fig. 1 will be referred to as the "front" and the right side as the "rear." Furthermore, the direction along the rotation axis Z in Fig. 1 will be referred to as the "axial direction," the direction perpendicular to the rotation axis Z as the "radial direction," and the direction around the rotation axis Z as the "circumferential direction."

As shown in FIG. 1, the propeller shaft PS according to this embodiment is disposed between a first shaft member 1, which is connected to a drive source (e.g., a transmission) of a vehicle (not shown), and a second shaft member 2, which is connected to a drive wheel (e.g., a differential) of the vehicle (not shown). Specifically, the propeller shaft PS includes a drive shaft 3, which is connected to the first shaft member 1 via a first constant velocity joint J1 for integral rotation, and a driven shaft 4, which is connected to the second shaft member 2 via a second constant velocity joint J2 for integral rotation. The drive shaft 3 and driven shaft 4 are also connected to each other via a third constant velocity joint J3 for integral rotation. The propeller shaft PS is rotatably supported on the vehicle floor (not shown) via a center bearing CB, which is suspended from the vehicle floor (not shown) via a well-known bracket BKT provided near the third constant velocity joint J3.

(Configuration of constant velocity joint)
Fig. 2 is an exploded view of the main parts of the propeller shaft PS, in which the second constant velocity joint J2, the boot member 9, and the second shaft member 2 shown in part A in Fig. 1 are axially disassembled. Fig. 3 is an enlarged view of part A shown in Fig. 1, showing an enlarged view of the second constant velocity joint J2 to which the constant velocity joint according to the present invention is applied. Fig. 4 is an enlarged view of the main parts of the second constant velocity joint J2 shown in Fig. 2, showing the boot member 9 assembled to the second constant velocity joint J2 and before the second shaft member 2 is connected to the inner ring member 6. Fig. 5 is an enlarged view of part B in Fig. 3, showing the main parts of the second constant velocity joint J2 with the second shaft member 2 connected to the inner ring member 6. Note that the first constant velocity joint J1 and the second constant velocity joint J2 according to this embodiment, to which the constant velocity joint according to the present invention is applied, have the same structure. Therefore, for the sake of convenience, a detailed description of the configuration of the first constant velocity joint J1 will be omitted below, and only the configuration of the second constant velocity joint J2 will be described in detail as an example of a constant velocity joint according to the present invention.

As shown in Figures 2, 3, and 5, for example, the second shaft member 2 is made of an iron-based metal material and is formed with a stepped diameter at the tip end. When inserted into the second constant velocity joint J2 from the rear end, it is secured inside the second constant velocity joint J2 by a well-known retaining ring RG, such as a circlip. The second shaft member 2 has a large diameter portion 21 connected to the drive wheels (differential) (not shown), a medium diameter portion 22 connected to the rear end of the large diameter portion 21, and a small diameter portion 23 connected to the rear end of the medium diameter portion 22, which are integrally formed.

The small diameter portion 23 has a male spline portion 231 formed axially on its outer periphery. A circumferentially continuous male spline-side annular groove 232 is formed on the outer periphery of the tip of the small diameter portion 23 at an axial position overlapping the male spline portion 231. A well-known retaining ring RG, such as the snap ring, is attached to this male spline-side annular groove 232. In other words, the retaining ring RG engages with the female spline-side annular groove 62 (described below), thereby restricting axial movement of the second shaft member 2 relative to the second constant velocity joint J2 (inner ring member 6).

The second constant velocity joint J2 has an outer ring member 5 connected to the rear end of the second tube 40 (see Figure 1) which serves as a cylindrical member constituting the driven shaft 4; an inner ring member 6 which is disposed on the inner periphery of the outer ring member 5 (the accommodation space S described below) and which is spline-fitted to the outer periphery of the second shaft member 2; a plurality of balls 7 which serve as rolling elements and are disposed between the inner ring member 6 and the outer ring member 5 so as to be able to roll; and a cage 8 which holds each ball 7.

The outer ring member 5 has a front end connected to the generally cylindrical second tube 40 (see Figure 1) and an open rear end formed in a cup shape, forming an internal storage space S capable of accommodating the inner ring member 6. The inner periphery of the outer ring member 5 is provided with a plurality of outer ring side engagement grooves 51 that extend axially and accommodate the balls 7 in a rollable manner, with the balls 7 engaging in the circumferential direction, spaced equally apart in the circumferential direction. The balls 7 roll in their respective outer ring side engagement grooves 51, allowing relative axial movement between the outer ring member 5 and the inner ring member 6, while the balls 7 engage with their respective outer ring side engagement grooves 51, restricting relative circumferential movement between the outer ring member 5 and the inner ring member 6.

The inner ring member 6 is generally cylindrical and has a shaft insertion section 60 through which the second shaft member 2 is inserted in the axial direction. The inner peripheral side of the shaft insertion section 60 has a female spline section 61 that mates with the male spline section 231 of the second shaft member 2. The inner peripheral side of the inner ring member 6 also has a series of female spline annular grooves 62 formed along the circumferential direction at axial positions radially opposite the male spline annular grooves 232 when the second shaft member 2 is inserted into the inner ring member 6. A retaining ring RG fitted to the second shaft member 2 can be engaged with the female spline annular grooves 62. The inner peripheral side of the inner ring member 6 also has a number of inner ring engagement grooves 63 formed along the axial direction at circumferential positions radially opposite the outer ring engagement grooves 51 of the outer ring member 5. These inner ring engagement grooves 63 are used for rolling and engaging the balls 7.

Each ball 7 is rollably housed in a track portion formed by the combination of an outer ring side engagement groove 51 and an inner ring side engagement groove 63. Furthermore, each ball 7 engages with its respective outer ring side engagement groove 51 and inner ring side engagement groove 63 in a state where relative rotation is restricted. This enables torque transmission between the outer ring member 5 and the inner ring member 6 while maintaining uniform velocity. Furthermore, each ball 7's rolling in the track portion is lubricated by grease (not shown) filled in the accommodation space S between the outer ring member 5 and the inner ring member 6.

The cage 8 is approximately cylindrical and has multiple windows 80 formed along the radial direction at predetermined circumferential positions, the same number as the balls 7. Each window 80 of the cage 8 accommodates and holds a ball 7 so that it can roll.

With the above configuration, when rotational torque is input to the second shaft member 2, the second constant velocity joint J2 transmits this rotational torque from the inner ring member 6, which rotates integrally with the second shaft member 2, to the outer ring member 5 via the balls 7. This allows the rotational torque input from the driven shaft 4 to be transmitted from the driven shaft 4 to the second shaft member 2 while maintaining a constant velocity.

Furthermore, when the front end of the inner ring member 6 is defined as the first end E1 and the rear end as the second end E2, the shaft insertion portion 60 of the inner ring member 6 is formed with a sleeve engagement portion 64 at the open end near the rear end (second end E2) that can engage with a sleeve portion 92 of the boot member 9 (described later). The sleeve engagement portion 64 has an inner diameter R2 that is larger than the inner diameter R1 of the shaft insertion portion 60 throughout the axial direction, and is formed in a stepped diameter expansion shape relative to the shaft insertion portion 60. Specifically, the sleeve engagement portion 64 has a tapered surface 640 that is generally conically tapered, with the largest inner diameter at the front end (first end E1) and gradually decreasing toward the rear end (second end E2). In other words, when the sleeve portion 92 of the boot member 9 (described later) abuts against the tapered surface 640 of the sleeve engagement portion 64, the sleeve portion 92 engages with the sleeve engagement portion 64, preventing the sleeve portion 92 from falling off the sleeve engagement portion 64.

A boot member 9, which protects the interior of the second constant velocity joint J2 from moisture and dust, is mounted between the outer ring member 5 and the inner ring member 6, straddling both members. The boot member 9 includes an adapter portion 91 that is crimped to the outer peripheral surface of the rear end of the outer ring member 5, a sleeve portion 92 that is positioned radially inward of the adapter portion 91 and engages with the sleeve engagement portion 64 of the inner ring member 6, and a boot portion 93 that connects the adapter portion 91 and the sleeve portion 92.

The adapter portion 91 is formed in an annular shape from a metal material such as SPCC or SPCE, and is formed so that its inner diameter expands in a stepped manner toward the front end opposite the outer ring member 5. Specifically, the adapter portion 91 integrally comprises an outer ring fixing portion 911 that is fixed to the outer peripheral surface 501 of the rear end of the outer ring member 5, and an adapter-side boot connecting portion 913 that reduces in diameter in a stepped manner from the outer ring fixing portion 911 via a step portion 912 and is fixed so as to sandwich the outer peripheral end of the boot portion 93.

The outer ring fixing portion 911 has a general portion 911a formed with a constant outer diameter along the outer peripheral surface 501 of the rear end of the outer ring member 5, and a crimped portion 911b formed as a recess at the tip of the general portion 911a and crimped into a recess 502 at the front end of the outer peripheral surface 501 of the rear end of the outer ring member 5. A continuous annular seal groove 503 is formed in the circumferential direction on the outer peripheral surface 501 of the rear end of the outer ring member 5. An annular seal member SL is fitted into the seal groove 503. The seal member SL elastically contacts the inner peripheral surface of the general portion 911a of the adapter portion 91, thereby providing a liquid-tight seal between the outer ring member 5 and the adapter portion 91.

The sleeve portion 92 is formed in a generally annular shape from a thin steel plate made of a metal material different from that of the adapter portion 91, such as SPC or SUS. As shown in FIG. 4 , the base end of the sleeve portion 92 is connected to the boot portion 93 by being embedded in the boot portion 93, while the tip end is exposed from the boot portion 93 and engages with the sleeve engagement portion 64, connecting to the inner ring member 6. Specifically, the sleeve portion 92 has an exposed sleeve portion 921 that is exposed from the boot portion 93 and extends toward the inner ring member 6, and an embedded sleeve portion 922 that is embedded in the boot portion 93.

As shown in Figures 2 and 4, before the second shaft member 2 is inserted (hereinafter referred to as the "free state" in this embodiment), the exposed sleeve portion 921 has a reduced-diameter sleeve portion 921a that gradually reduces in diameter from the sleeve connection portion 932 (described later) of the boot portion 93 toward the front end (sleeve engagement portion 64 side), and a tapered expanded-diameter sleeve portion 921b that gradually expands in diameter from the reduced-diameter sleeve portion 921a toward the front end (sleeve engagement portion 64 side) and expands along the tapered surface 640 of the sleeve engagement portion 64.

The exposed sleeve portion 921 also has multiple slits 921c that open toward the tip of the expanded-diameter sleeve portion 921b and extend linearly toward the reduced-diameter sleeve portion 921a. These multiple slits 921c are arranged in parallel at equal intervals around the circumference of the exposed sleeve portion 921 and are cut out along the extension direction of the exposed sleeve portion 921. The provision of the slits 921c reduces the rigidity of the exposed sleeve portion 921, making it easier for the exposed sleeve portion 921 to elastically deform, and facilitating the engagement of the exposed sleeve portion 921 with the sleeve engagement portion 64.

As shown in particular in Figure 4, the embedded sleeve portion 922 has an expanded diameter portion 922a that expands in diameter as it moves axially away from the inner ring member 6 in a free state (before the second shaft member 2 is inserted), and a folded portion 922b that is folded back radially outward from the inner end (rear end) of the expanded diameter portion 922a in the axial direction. As described below, when the second shaft member 2 is inserted into the inner periphery of the sleeve portion 92, the folded portion 922b resists the sleeve portion 92 being pulled into the sleeve engagement portion 64 as the second shaft member 2 is inserted, ensuring a relatively strong connection between the sleeve portion 92 and the sleeve connection portion 932.

As shown in Figure 2, the boot portion 93 is formed in a radially extending ring shape from an elastic material such as rubber. Specifically, the boot portion 93 integrally includes an adapter connection portion 931 that connects to the adapter portion 91, a sleeve connection portion 932 that connects to the sleeve portion 92, and a flexible portion 933 that flexibly connects the front end of the adapter connection portion 931 to the front end of the sleeve connection portion 932.

The adapter connection portion 931 is connected to the adapter portion 91 by being sandwiched between the adapter-side boot connection portion 913 of the adapter portion 91. The sleeve connection portion 932 is generally cylindrical and provided on the inner periphery of the adapter connection portion 931, and is connected to the sleeve portion 92 by embedding the base end (rear end) of the sleeve portion 92 inside. The flexible portion 933 is formed with a relatively thin wall and is curved back so as to be convex toward the second constant velocity joint J2. By flexing and deforming as the second constant velocity joint J2 bends, it constantly covers the storage space S that opens to the rear end side of the second constant velocity joint J2.

The sleeve connection portion 932 also has a first seal portion 934 that protrudes circumferentially from its inner circumferential side, which faces the second shaft member 2 in the radial direction. The inner diameter of the tip of this first seal portion 934 is set smaller than the outer diameter of the medium-diameter portion 22 of the second shaft member 2. When the second shaft member 2 is inserted into the inner circumferential side of the sleeve portion 92, the first seal portion 934 is able to elastically contact the outer circumferential surface 220 of the medium-diameter portion 22 of the second shaft member 2. Furthermore, the front and rear ends of the first seal portion 934 are tapered, with a first tapered portion 934a formed on the front end and a second tapered portion 934b formed on the rear end. The second tapered portion 934b is formed so that its inclination angle with respect to the rotation axis Z is relatively gentler than the first tapered portion 934a. This improves the ease of insertion of the second shaft member 2, which is inserted from the rear end.

The sleeve connection portion 932 is adjacent to the first seal portion 934 on the side farther from the inner ring member 6 in the axial direction than the first seal portion 934, and has a second seal portion 935 that protrudes circumferentially on the inner peripheral side radially facing the second shaft member 2. The inner diameter of the tip of this second seal portion 935 is set to be equal to the outer diameter of the medium diameter portion 22 of the second shaft member 2, and is arranged so that it can come into close proximity to or abut against the outer peripheral surface 220 of the medium diameter portion 22 of the second shaft member 2 when the second shaft member 2 is inserted into the inner peripheral side of the sleeve portion 92.

(Boot member assembly method)
6A and 6B are enlarged views of essential parts of the second constant velocity joint J2 illustrating the assembly process of the second constant velocity joint J2, in which (a) shows the state before the sleeve portion 92 is assembled to the inner ring member 6, and (b) shows the state after the sleeve portion 92 has been engaged with the inner ring member 6.

First, as shown in Figure 6(a), the adapter portion 91 of the boot member 9, which is arranged axially opposite the rear end of the second constant velocity joint J2, is fitted onto the rear end of the outer ring member 5.

Next, as shown in Figure 6(b), the adapter portion 91 is pushed into the outer ring member 5 until the step 912 of the adapter portion 91 abuts the rear end surface 500 of the outer ring member 5. At the same time, the tip of the exposed sleeve portion 921 of the sleeve portion 92 is narrowed so that the outer diameter of the tip of the exposed sleeve portion 921 is smaller than the inner diameter of the opening of the sleeve engagement portion 64. In this state, the tip of the exposed sleeve portion 921 is fitted into the sleeve engagement portion 64 of the inner ring member 6, causing the tip of the exposed sleeve portion 921 to abut against and engage with the tapered surface 640 of the sleeve engagement portion 64.

Finally, the outer ring fixing portion 911 of the adapter portion 91 is crimped to fit into the recess 502 on the outer peripheral surface 501 of the rear end of the outer ring member 5, thereby fixing the outer ring fixing portion 911 of the adapter portion 91 to the outer peripheral surface 501 of the rear end of the outer ring member 5. This completes the assembly of the boot member 9 to the second constant velocity joint J2.

(Propeller shaft assembly method)
7A and 7B are enlarged views of the main parts of the second constant velocity joint J2, illustrating the process of assembling the propeller shaft PS to the second constant velocity joint J2. FIG. 7A shows the state immediately before the second shaft member 2 is inserted into the sleeve portion 92, and FIG. 7B shows the state after the second shaft member 2 has been inserted into the inner ring member 6.

First, as shown in Figure 7(a), the small-diameter portion 23 (male spline portion 231) of the second shaft member 2 is inserted into the inner periphery of the sleeve portion 92 of the boot member 9. As a result, the reduced-diameter sleeve portion 921a of the sleeve portion 92 is expanded in diameter by the male spline portion 231 of the second shaft member 2, and the tip end of the male spline portion 231 of the second shaft member 2 is fitted into the female spline portion 61 of the inner ring member 6.

7(b), the second shaft member 2 of the inner ring member 6 is further inserted axially until the retaining ring RG fitted onto the male spline portion 231 of the second shaft member 2 engages with the female spline-side annular groove 62. When the second shaft member 2 is at its maximum insertion position, the medium-diameter portion 22 of the second shaft member 2 is inserted into the inner periphery of the sleeve portion 92, causing the exposed sleeve portion 921 to expand in diameter and deform into a linear shape parallel to the rotation axis Z. Furthermore, as the second shaft member 2 is inserted, frictional forces are generated between the sleeve connection portion 932 and the medium-diameter portion 22, causing the sleeve portion 92 (exposed sleeve portion 921) to engage more deeply with the tapered surface 640 of the sleeve engagement portion 64 in both the axial and radial directions, thereby more firmly securing the sleeve portion 92 to the inner ring member 6. At the same time, the first seal portion 932a of the sleeve connection portion 932 of the boot member 9 rides up onto the outer circumferential surface 220 of the medium diameter portion 22 of the second shaft member 2, thereby creating a liquid-tight seal between the sleeve connection portion 932 and the medium diameter portion 22.

(Effects of this embodiment)
As described above, conventional constant velocity joints are configured such that a sleeve is press-fitted into an inner ring member, which increases the workload required to assemble a boot member into the constant velocity joint, and there is still room for improvement.

In contrast, the propeller shaft PS and the second constant velocity joint J2 used therein according to this embodiment provide the following effects, thereby resolving the issues associated with the conventional propeller shafts.

The second constant velocity joint J2 used in the propeller shaft PS comprises an inner ring member 6 having a shaft insertion portion 60 into which a shaft member (second shaft member 2) is inserted, a first end E1 and a second end E2, which are both ends of the shaft insertion portion 60 in the direction of the rotation axis Z, and a sleeve engagement portion 64 provided at the second end E2 into which the shaft member (second shaft member 2) is inserted and formed with a larger diameter than the shaft insertion portion 60 in the radial direction relative to the rotation axis Z, and a sleeve engagement portion 64 disposed outside the inner ring member 6 in the radial direction and an outer ring member 5 that forms an accommodation space S between itself and the outer ring member 6; a plurality of rolling elements (balls 7) that are rotatably accommodated in the accommodation space S, are interposed between the inner ring member 6 and the outer ring member 5 in the radial direction so as to be capable of transmitting torque, and rotate integrally with the inner ring member 6 and the outer ring member 5; a retainer 8 that is disposed in the accommodation space S and rotatably holds each rolling element (ball 7); and a boot member that closes an opening that opens into the accommodation space S on the side where the shaft member (second shaft member 2) is inserted in the direction of the rotation axis Z, The boot member 9 includes an adapter portion 91 fixed to the outer periphery of the member 5, a sleeve portion 92 that engages with the sleeve engagement portion 64 and through which the shaft member (second shaft member 2) is inserted on its inner periphery, and a boot portion 93 that is provided radially between the adapter portion 91 and the sleeve portion 92 and covers the opening. The boot portion 93 includes an adapter connection portion 931 that connects to the adapter portion 91, a sleeve connection portion 932 that is cylindrically provided on the inner periphery of the adapter connection portion 931 and connected to the sleeve portion 92, and a flexible portion 933 that flexibly connects the adapter connection portion 931 and the sleeve connection portion 932. The sleeve portion 92 is formed cylindrically from a metal member that is partially embedded in the sleeve connection portion 932 in the direction of the rotation axis Z, and protrudes from the sleeve connection portion 932 toward the sleeve engagement portion 64 and bends radially away from the rotation axis Z as it approaches the sleeve engagement portion 64, thereby abutting and engaging with the inner periphery of the sleeve engagement portion 64.

In other words, the propeller shaft PS is a propeller shaft comprising a cylindrical member (second tube 40) and a constant velocity joint (second constant velocity joint J2) that connects the cylindrical member (second tube 40) to a shaft member (second shaft member 2) on the vehicle side. The second constant velocity joint J2 is provided at the shaft insertion portion 60 into which the shaft member (second shaft member 2) is inserted, and at the second end E2 of the shaft insertion portion 60, which are the first end E1 and the second end E2 that are both ends in the direction of the rotation axis Z, into which the shaft member (second shaft member 2) is inserted. The second constant velocity joint J2 is provided at the second end E2 into which the shaft member (second shaft member 2) is inserted, and is oriented radially relative to the rotation axis Z. and a sleeve engaging portion 64 formed with a diameter larger than that of the shaft insertion portion 60 in the inner ring member 6; an outer ring member 5 disposed outside the inner ring member 6 in the radial direction and forming an accommodation space S between the inner ring member 6 and the outer ring member 5; a plurality of rolling elements (balls 7) that are accommodated in the accommodation space S in a rollable manner, are interposed between the inner ring member 6 and the outer ring member 5 in the radial direction so as to be able to transmit torque, and rotate integrally with the inner ring member 6 and the outer ring member 5; a cage 8 disposed in the accommodation space S and rotatably holds each rolling element (ball 7); The boot member closes an opening that opens to the side where the shaft member (second shaft member 2) is inserted, and includes an adapter portion 91 fixed to the outer peripheral side of the outer ring member 5, a sleeve portion 92 that engages with the sleeve engaging portion 64 and has the shaft member (second shaft member 2) inserted into the inner peripheral side, and a boot portion 93 that is provided between the adapter portion 91 and the sleeve portion 92 in the radial direction and covers the opening, and the boot portion 93 has an adapter connecting portion 931 that is connected to the adapter portion 91, and a sleeve portion 92 that is provided in a cylindrical shape on the inner peripheral side of the adapter connecting portion 931 and is connected to the sleeve portion 92. The sleeve portion 92 includes a sleeve connection portion 932 that is connected to the adapter connection portion 931 and a flexible portion 933 that flexibly connects the adapter connection portion 931 and the sleeve connection portion 932. The sleeve portion 92 is formed in a cylindrical shape from a metal member that is partially embedded in the sleeve connection portion 932 in the direction of the rotation axis Z, and has a boot member 9 that protrudes from the sleeve connection portion 932 toward the sleeve engagement portion 64 and bends radially away from the rotation axis Z as it approaches the sleeve engagement portion 64, and abuts against and engages with the inner peripheral side of the sleeve engagement portion 64.

As such, in this embodiment, the boot member 9 can be attached to the inner ring member 6 simply by engaging the sleeve portion 92 with the sleeve engagement portion 64 of the inner ring member 6. This eliminates the need to press-fit the sleeve portion 92 of the boot member 9 into the inner ring member 6, as was the case with the conventional constant velocity joint described above. This reduces the workload involved in attaching the boot member 9 to the inner ring member 6 and improves the ease of assembling the boot member 9 to the second constant velocity joint J2.

Furthermore, according to this embodiment, the sleeve portion 92 is configured to bend radially away from the rotation axis Z as it approaches the sleeve engagement portion 64, thereby abutting and engaging with the inner peripheral side of the sleeve engagement portion 64. In other words, the sleeve portion 92 is connected to the inner ring member 6 by the tapered expanded-diameter sleeve portion 921b, which gradually expands in diameter toward its tip, elastically deforming and engaging with the sleeve engagement portion 64. Therefore, when the second shaft member 2 is pulled out of the inner ring member 6, for example, during maintenance of the propeller shaft PS, the elastic deformation of the sleeve portion 92 allows the sleeve portion 92 to disengage from the sleeve engagement portion 64 without damage. As a result, even if the sleeve portion 92 has become stuck to the second shaft member 2 due to rust or other factors over time, unlike when the sleeve portion 92 is firmly fixed to the inner ring member 6 by press-fitting, excessive force is not applied to the sleeve portion 92 when the second shaft member 2 is pulled out, thereby preventing damage to the sleeve portion 92 or the boot portion 93. As a result, the boot member 9 can be reused, eliminating the risk of having to replace the propeller shaft PS due to damage to the boot member 9.

In addition, in this embodiment, the sleeve engagement portion 64 decreases in distance from the rotation axis Z as it moves away from the first end E1 in the direction of the rotation axis Z.

As such, in this embodiment, the distance of the sleeve engaging portion 64 from the rotation axis Z, i.e., the inner diameter of the sleeve engaging portion 64, is configured to decrease the closer it is to the boot portion 93. Therefore, the inner diameter of the sleeve portion 92 that engages with the sleeve engaging portion 64 is made smaller the closer it is to the boot portion 93, making it possible to increase the spring force of the sleeve portion 92 against the second shaft member 2 when the second shaft member 2 is inserted. This makes it possible to achieve both the ability to engage the tip end of the sleeve portion 92, which is bent to expand in diameter, with the sleeve engaging portion 64 and the ability to connect the reduced base end of the sleeve portion 92 to the second shaft member 2.

In addition, in this embodiment, the sleeve connection portion 932 of the boot portion 93 has a first seal portion 934 on the inner circumferential side facing the shaft member (second shaft member 2) in the radial direction, and the first seal portion 934 is in elastic contact with the outer circumferential surface of the shaft member (second shaft member 2) when the shaft member (second shaft member 2) is inserted into the inner circumferential side of the sleeve portion 92.

As such, in this embodiment, a first seal portion 934 that can abut against the outer peripheral surface of the second shaft member 2 (the outer peripheral surface 220 of the medium diameter portion 22) is provided on the inner peripheral side of the sleeve connection portion 932. This enables the first seal portion 934 to provide a liquid-tight seal between the boot member 9 and the second shaft member 2, making it possible to eliminate sealing members such as O-rings that were previously placed between the boot member 9 and the second shaft member 2. As a result, it is possible to improve the ease of assembly of the second constant velocity joint J2 and reduce manufacturing costs.

Furthermore, according to this embodiment, the first seal portion 934 is provided at the sleeve connection portion 932. The sealing action of this first seal portion 934 prevents moisture from entering the area inside the sleeve connection portion 932 (the front end side in the case of the second constant velocity joint J2). This eliminates the risk of moisture entering the boot member 9 causing rust on the sleeve portion 92 and causing the sleeve portion 92 to adhere to the second shaft member 2 or the inner ring member 6. This ensures smooth release of the sleeve portion 92 from the second shaft member 2 and the inner ring member 6 during maintenance of the propeller shaft PS, as described above, and more effectively prevents damage to the boot member 9.

In addition, in this embodiment, the sleeve connection portion 932 has a second seal portion 935 on the inner circumferential side facing the shaft member (second shaft member 2) in the radial direction, on a side farther away from the inner ring member 6 than the first seal portion 934 in the direction of the rotation axis Z, and the second seal portion 935 is in close proximity to or in contact with the outer circumferential surface of the shaft member (second shaft member 2) when the shaft member (second shaft member 2) is inserted into the inner circumferential side of the sleeve portion 92.

In this manner, in this embodiment, a second seal portion 935 that can come into close proximity with or abut against the outer peripheral surface of the second shaft member 2 (the outer peripheral surface 220 of the medium diameter portion 22) is provided on the inner peripheral side of the sleeve connection portion 932. Therefore, in addition to the first seal portion 934, the second seal portion 935 can also seal between the boot member 9 and the second shaft member 2. As a result, for example, the first seal portion 934 can retain grease filled inside the housing space S, while the second seal portion 935 can prevent water and dust from entering from the outside.

In particular, the second seal portion 935 is only in close proximity to or in contact with the second shaft member 2, and does not have a clamping margin with the outer surface of the second shaft member 2 (the outer surface 220 of the medium diameter portion 22) like the first seal portion 934, ensuring good insertion of the second shaft member 2.

In addition, in this embodiment, the sleeve engagement portion 64 has a tapered surface 640 that gradually reduces in diameter toward the second end E2, and the sleeve portion 92 has an exposed sleeve portion 921 that is exposed from the sleeve connection portion 932 and protrudes toward the sleeve engagement portion 64, and an embedded sleeve portion 922 that is embedded inside the sleeve connection portion 932. The exposed sleeve portion 921 has a reduced-diameter sleeve portion 921a that reduces in diameter from the sleeve connection portion 932 toward the sleeve engagement portion 64, and a tapered expanded-diameter sleeve portion 921b that gradually expands in diameter from the reduced-diameter sleeve portion 921a toward the sleeve engagement portion 64, expanding along the tapered surface 640 of the sleeve engagement portion 64.

As such, in this embodiment, the exposed sleeve portion 921 has a reduced diameter on the sleeve connection portion 932 side and an expanded diameter on the sleeve engagement portion 64 side along the tapered surface 640 of the sleeve engagement portion 64. As a result, when the second shaft member 2 is inserted into the inner periphery of the sleeve portion 92, the reduced-diameter sleeve portion 921a undergoes an expanded diameter deformation, and as a result of this expanded diameter deformation, the expanded-diameter sleeve portion 921b penetrates significantly (deeply) into the sleeve engagement portion 64 side, thereby achieving a strong engagement state of the sleeve portion 92 with the sleeve engagement portion 64.

Furthermore, according to this embodiment, the base end of the sleeve portion 92 in the embedded sleeve portion 922 is formed integrally with the boot portion 93. Therefore, compared to conventional constant velocity joints in which the boot portion 93 is fastened to the sleeve portion 92 via a well-known boot band, the process of connecting the boot portion 93 to the sleeve portion 92 is eliminated, and the boot member 9 and inner ring member 6 can be connected simply by engaging the sleeve portion 92 with the sleeve engagement portion 64. This further reduces the workload of attaching the boot member 9 to the inner ring member 6, further improving the ease of assembly of the second constant velocity joint J2.

In addition, in this embodiment, the sleeve portion 92 has an exposed sleeve portion 921 that is exposed from the sleeve connecting portion 932 and protrudes toward the sleeve engaging portion 64, and an embedded sleeve portion 922 that is embedded inside the sleeve connecting portion 932. The embedded sleeve portion 922 has an expanded diameter portion 922a that expands in diameter as it moves away from the inner ring member 6 in the direction of the rotation axis Z, and a folded portion 922b that is folded back radially outward from the inner end of the expanded diameter portion 922a in the direction of the rotation axis Z.

In this manner, in this embodiment, the inner end of the embedded sleeve portion 922 is folded radially outward. Therefore, when the sleeve portion 92 is pushed into the sleeve engagement portion 64 as the second shaft member 2 is inserted into the inner periphery of the sleeve portion 92 (exposed sleeve portion 921), the folded portion 922b of the embedded sleeve portion 922 resists the insertion of the sleeve portion 92 into the sleeve engagement portion 64, thereby improving the retention of the embedded sleeve portion 922 within the sleeve connection portion 932.

In addition, in this embodiment, the sleeve portion 92 has an exposed sleeve portion 921 that is exposed from the sleeve connection portion 932 and protrudes toward the sleeve engagement portion 64, and an embedded sleeve portion 922 that is embedded inside the sleeve connection portion 932. The exposed sleeve portion 921 has a tapered expanded diameter sleeve portion 921b that expands in diameter toward the sleeve engagement portion 64, and a slit portion 921c that is cut out from the tip of the expanded diameter sleeve portion 921b along the extension direction of the expanded diameter sleeve portion 921b.

As such, in this embodiment, a slit portion 921c is formed in the exposed sleeve portion 921 from the tip of the expanded diameter sleeve portion 921b along the extension direction of the expanded diameter sleeve portion 921b. This reduces the rigidity of the exposed sleeve portion 921, making it relatively easy to elastically deform the exposed sleeve portion 921. As a result, it becomes easier to engage the sleeve portion 92 (exposed sleeve portion 921) with the sleeve engagement portion 64, improving the ease of assembly of the second constant velocity joint J2.

The present invention is not limited to the configurations and aspects exemplified in the above embodiments, and can be freely modified depending on the specifications and costs of the target application as long as the above-mentioned effects of the present invention can be achieved.

For example, in the above embodiment, the first shaft member 1 is the output shaft of a transmission of a vehicle (not shown), and the second shaft member 2 is the input shaft of a differential device of a vehicle (not shown), but the reverse may also be true.

Furthermore, in the case of a vehicle in which the transmission is provided on the drive wheel (rear wheel) side, the first shaft member 1 may be the engine output shaft and the second shaft member may be the transmission input shaft, or vice versa.

The present invention can also be applied to vehicles that use an electric motor as a continuously variable reducer instead of the transmission.

1...First shaft member (shaft member), 2...Second shaft member (shaft member), 3...Drive shaft, 4...Driven shaft, 5...Outer ring member, 6...Inner ring member, 7...Ball (rolling element), 8...Cage, 9...Boot member, 40...Second tube (cylindrical member), 60...Shaft insertion portion, 91...Adapter portion, 92...Sleeve portion, 93...Boot portion, 931...Adapter connection portion, 932...Sleeve connection portion, 933...Flexible portion, PS...Propeller shaft, J1...First constant velocity joint (constant velocity joint), J2...Second constant velocity joint (constant velocity joint), E1...First end portion, E2...Second end portion,

Claims (11)

an inner ring member having a shaft insertion portion into which a shaft member is inserted, and a sleeve engaging portion provided at the second end into which the shaft member is inserted, of a first end and a second end which are both ends of the shaft insertion portion in the direction of the rotation axis of the shaft member, and formed with a larger diameter than the shaft insertion portion in a radial direction relative to the rotation axis;
an outer ring member disposed outside the inner ring member in the radial direction and forming an accommodation space between the outer ring member and the inner ring member;
a plurality of rolling elements that are rotatably accommodated in the accommodation space, are interposed between the inner ring member and the outer ring member in the radial direction so as to be capable of transmitting torque, and rotate integrally with the inner ring member and the outer ring member;
a cage disposed in the accommodation space and configured to rotatably hold the rolling elements;
a boot member that closes an opening of the accommodation space that opens to a side into which the shaft member is inserted in the direction of the rotation axis,
an adapter portion fixed to the outer peripheral side of the outer ring member; a sleeve portion that engages with the sleeve engaging portion and through which the shaft member is inserted on the inner peripheral side; and a boot portion that is provided between the adapter portion and the sleeve portion in the radial direction and covers the opening,
the boot portion includes an adapter connecting portion connected to the adapter portion, a sleeve connecting portion provided cylindrically on the inner circumferential side of the adapter connecting portion and connected to the sleeve portion, and a flexible portion connecting the adapter connecting portion and the sleeve connecting portion in a flexible manner,
The sleeve portion is formed in a cylindrical shape from a metal member, a portion of which is embedded in the sleeve connection portion in the direction of the rotation axis, protrudes from the sleeve connection portion toward the sleeve engagement portion, and is bent in the radial direction so as to move away from the rotation axis as it approaches the sleeve engagement portion, and abuts against and engages with the inner peripheral side of the sleeve engagement portion.
the boot member;
A constant velocity joint comprising: 2. The constant velocity joint according to claim 1,
the sleeve engagement portion has a distance from the rotation axis that decreases as the sleeve engagement portion moves away from the first end in the direction of the rotation axis;
A constant velocity joint characterized by: 2. The constant velocity joint according to claim 1,
the sleeve connection portion of the boot portion has a first seal portion on an inner peripheral side facing the shaft member in the radial direction,
the first seal portion elastically contacts an outer peripheral surface of the shaft member in a state in which the shaft member is inserted into the inner peripheral side of the sleeve portion;
A constant velocity joint characterized by: 4. The constant velocity joint according to claim 3,
the sleeve connection portion has a second seal portion on a side farther away from the inner ring member than the first seal portion in the direction of the rotation axis and on an inner peripheral side facing the shaft member in the radial direction,
the second seal portion is in close proximity to or in contact with an outer circumferential surface of the shaft member when the shaft member is inserted into the inner circumferential side of the sleeve portion;
A constant velocity joint characterized by: 4. The constant velocity joint according to claim 3,
The sleeve engaging portion has a tapered surface that gradually reduces in diameter toward the second end portion,
the sleeve portion has an exposed sleeve portion that is exposed from the sleeve connecting portion and protrudes toward the sleeve engaging portion, and an embedded sleeve portion that is embedded inside the sleeve connecting portion,
The exposed sleeve portion has a reduced-diameter sleeve portion whose diameter is reduced from the sleeve connection portion toward the sleeve engaging portion side, and a tapered expanded-diameter sleeve portion whose diameter is gradually increased from the reduced-diameter sleeve portion toward the sleeve engaging portion side and which expands along the tapered surface of the sleeve engaging portion.
A constant velocity joint characterized by: 3. The constant velocity joint according to claim 2,
the sleeve portion has an exposed sleeve portion that is exposed from the sleeve connecting portion and protrudes toward the sleeve engaging portion, and an embedded sleeve portion that is embedded inside the sleeve connecting portion,
The embedded sleeve portion has an expanded diameter portion whose diameter increases as it moves away from the inner ring member in the direction of the rotation axis, and a folded portion formed in a folded shape from an inner end of the expanded diameter portion to an outer side in the radial direction in the direction of the rotation axis.
A constant velocity joint characterized by: 2. The constant velocity joint according to claim 1,
the sleeve portion has an exposed sleeve portion that is exposed from the sleeve connecting portion and protrudes toward the sleeve engaging portion, and an embedded sleeve portion that is embedded inside the sleeve connecting portion,
The exposed sleeve portion has a tapered enlarged-diameter sleeve portion whose diameter increases toward the sleeve engagement portion, and a slit portion cut out from a tip of the enlarged-diameter sleeve portion along an extending direction of the enlarged-diameter sleeve portion.
A constant velocity joint characterized by: 2. The constant velocity joint according to claim 1,
The adapter portion is formed of a metal material.
A constant velocity joint characterized by: 2. The constant velocity joint according to claim 1,
The boot portion is formed of a rubber material.
A constant velocity joint characterized by: 2. The constant velocity joint according to claim 1,
The sleeve portion is formed of an elastic metal material.
A constant velocity joint characterized by: A propeller shaft including a cylindrical member and a constant velocity joint connecting the cylindrical member and a shaft member on a vehicle side,
The constant velocity joint is
an inner ring member having a shaft insertion portion into which the shaft member is inserted, and a sleeve engaging portion provided at the second end into which the shaft member is inserted, of a first end and a second end which are both ends of the shaft insertion portion in the direction of the rotation axis of the shaft member, the sleeve engaging portion being formed with a larger diameter than the shaft insertion portion in the radial direction relative to the rotation axis;
an outer ring member disposed outside the inner ring member in the radial direction and forming an accommodation space between the outer ring member and the inner ring member;
a plurality of rolling elements that are rotatably accommodated in the accommodation space, are interposed between the inner ring member and the outer ring member in the radial direction so as to be capable of transmitting torque, and rotate integrally with the inner ring member and the outer ring member;
a cage disposed in the accommodation space and configured to rotatably hold the rolling elements;
a boot member that closes an opening of the accommodation space that opens to a side into which the shaft member is inserted in the direction of the rotation axis,
an adapter portion fixed to the outer peripheral side of the outer ring member; a sleeve portion that engages with the sleeve engaging portion and through which the shaft member is inserted on the inner peripheral side; and a boot portion that is provided between the adapter portion and the sleeve portion in the radial direction and covers the opening,
the boot portion includes an adapter connecting portion connected to the adapter portion, a sleeve connecting portion provided cylindrically on the inner circumferential side of the adapter connecting portion and connected to the sleeve portion, and a flexible portion connecting the adapter connecting portion and the sleeve connecting portion in a flexible manner,
The sleeve portion is formed in a cylindrical shape from a metal member, a portion of which is embedded in the sleeve connection portion in the direction of the rotation axis, protrudes from the sleeve connection portion toward the sleeve engagement portion, and is bent in the radial direction so as to move away from the rotation axis as it approaches the sleeve engagement portion, and abuts against and engages with the inner peripheral side of the sleeve engagement portion.
the boot member;
A propeller shaft comprising: