WO2017082068A1 - Sliding constant-velocity universal joint - Google Patents

Abstract

Provided is a sliding constant-velocity universal joint provided with a cup-shaped outer joint member 11 and an inner joint member 12 for transmitting torque while allowing axial displacement and angular displacement relative to the outer joint member 11 via a ball 13, the inner joint member 12 being accommodated in the outer joint member 11, and a shaft 15 being linked to the inner joint member 12 such that torque can be transmitted; wherein: a plurality of axially extending protrusions are formed on the outer peripheral surface of the shaft 15; recesses that have clearance with the protrusions are formed in the inner peripheral surface of the inner joint member 12; the shaft 15 is press-fitted into the inner joint member 12; and the shapes of the protrusions are transferred to the recess-forming surface of the inner joint member 12, whereby a recess/protrusion fitting portion 45 is provided for firm adherence in the entire area of the section of fitted contact between the protrusions and the recesses, and the shaft 15 can be axially displaced relative to the inner joint member 12 by an axial load greater than the bonding force in the recess/protrusion fitting portion 45.

Description

Sliding constant velocity universal joint

The present invention relates to a sliding type constant velocity universal joint that is used in a power transmission system of an automobile or various industrial machines, and is particularly incorporated in a propeller shaft for an automobile.

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

Propeller shafts incorporated in automobiles such as 4WD vehicles and FR vehicles include sliding-type constant velocity universal joints so as to be able to cope with axial displacement and angular displacement due to relative position changes between the transmission and the differential. The propeller shaft is configured by a combination of a sliding constant velocity universal joint and a steel tubular member, and is attached to the vehicle substantially parallel to the vehicle traveling direction.

The sliding type constant velocity universal joint includes an outer joint member, an inner joint member, a plurality of balls, and a cage, and a shaft that extends from the inner joint member and projects from an opening of the outer joint member is coupled thereto. The inner joint member, ball and cage are housed inside the outer joint member. The shaft is connected to the shaft hole of the inner joint member so that torque can be transmitted by spline fitting. The shaft is prevented from coming off from the inner joint member by a retaining ring.

潤滑 Lubricant is sealed in the inner space of the outer joint member. Thereby, the lubricity at the sliding part inside the joint is ensured when the shaft rotates while taking an operating angle with respect to the outer joint member. A boot for preventing entry of foreign matter from the outside of the joint and leakage of lubricant from the inside of the joint is mounted between the one open end of the outer joint member and the shaft.

On the other hand, a steel tubular member is coaxially connected and fixed to the other opening end of the outer joint member by joining such as friction welding or arc welding. In addition, a seal plate is fitted to the inner peripheral surface of the outer joint member at the other opening end of the outer joint member in order to prevent entry of foreign matter from the outside of the joint and leakage of lubricant from the inside of the joint. .

In the constant velocity universal joint for propeller shafts configured as described above, for example, a buffer mechanism that absorbs an axial displacement caused by a relative position change between a transmission and a differential caused by a vehicle collision or the like is provided.

As this buffering mechanism, the seal plate is punched out by the axial load at the time of a vehicle collision, and the inner part consisting of the inner joint member, ball and cage is slid over the outer joint member in the axial direction and enters the inside of the tubular member. I try to make it. Thereby, the impact which arises in a vehicle body is reduced and the improvement of safety is aimed at (for example, refer to patent documents 1).

Japanese Patent No. 3958621

By the way, in the constant velocity universal joint disclosed in Patent Document 1, the inner joint member and the shaft are firmly fastened in the axial direction by using a retaining part such as a retaining ring, and the inner joint member and the shaft are connected to the outer joint member. As a unit, it is slidable in the axial direction.

As described above, since the inner joint member and the shaft are integrated with the outer joint member so as to be slidable in the axial direction, when the axial load is applied at the time of a vehicle collision, the inner joint member The seal plate is punched out integrally with the internal parts including the member, the ball and the cage.

Therefore, the outer diameter of the seal plate must inevitably be larger than the internal parts. As a result, the design freedom of the constant velocity universal joint is low. In addition, as described above, since the outer diameter of the seal plate is increased, the inner diameter of the tubular member that is coaxially connected and fixed to the opening end of the outer joint member is also reduced in order to allow internal components to enter with the seal plate. I have to make it bigger. Also in this point, the design freedom of the constant velocity universal joint is lowered, and the application range is limited.

As described above, since the shock absorbing mechanism that absorbs the axial load at the time of the vehicle collision is adopted by punching out the seal plate with the integrated internal parts, the periphery of the shock absorbing mechanism composed of the seal plate and the tubular member Depending on the design, when an axial load is applied during a vehicle collision, it is difficult to ensure a stable axial strength.

Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to secure a stable axial strength against an axial load at the time of a vehicle collision and to provide a degree of freedom in designing a shock absorbing mechanism. An object of the present invention is to provide a sliding type constant velocity universal joint capable of increasing the resistance.

A sliding type constant velocity universal joint according to the present invention is accommodated in a cup-shaped outer joint member and the outer joint member, and torque is allowed while allowing angular displacement between the outer joint member and a torque transmission member. An inner joint member for transmission, and a structure in which a shaft-like member is coupled to the inner joint member so as to transmit torque.

As a technical means for achieving the above-described object, the present invention forms a plurality of convex portions extending in the axial direction on the outer peripheral surface of the shaft-shaped member, and also projects the convex portions and the fastening margins on the inner peripheral surface of the inner joint member. Is formed, and the shaft-shaped member is press-fitted into the inner joint member, and the shape of the convex portion is transferred to the concave portion forming surface of the inner joint member, so that the entire fitting contact portion between the convex portion and the concave portion is in close contact with each other. An uneven fitting portion is provided, and the axial member can be displaced in the axial direction with respect to the inner joint member by an axial load larger than the joining force at the uneven fitting portion.

In the present invention, a plurality of convex portions extending in the axial direction are formed on the outer peripheral surface of the shaft-shaped member, and a concave portion having a convex portion and a tightening margin is formed on the inner peripheral surface of the inner joint member. The inner joint member is provided with a concave-convex fitting portion in which the entire fitting contact portion of the convex portion and the concave portion is in close contact by press-fitting into the member and transferring the shape of the convex portion to the concave portion forming surface of the inner joint member. And the shaft-like member are stably joined in the axial direction by the joining force at the concave-convex fitting portion. From this, when an axial load is applied at the time of a vehicle collision, a stable axial strength can be ensured.

In addition, the axial member can be displaced in the axial direction with respect to the inner joint member due to an axial load larger than the joining force at the concave-convex fitting portion. The shaft-shaped member is displaced in the axial direction with respect to the joint member. From this, it becomes easy to increase the degree of freedom in designing a shock absorbing mechanism that absorbs an axial load at the time of a vehicle collision. Furthermore, with this buffer mechanism, the degree of freedom in designing the constant velocity universal joint is increased in that a retaining mechanism such as a retaining ring for retaining the shaft-shaped member from the inner joint member is not required. Can do.

In the present invention, the bottom of the outer joint member forms a through hole that is larger than the outer diameter of the shaft-like member and smaller than the outer diameter of the inner joint member, and a seal plate is fitted into the through hole. It is desirable to have a structure in which the tubular members communicating with each other are joined, and the seal plate can be removed from the through hole by the axial displacement of the shaft-like member so as to enter the tubular member.

If such a structure is adopted, when an axial load is applied at the time of a vehicle collision, a shaft-like member that is axially displaced with respect to the inner joint member punches the seal plate from the through hole. The seal plate punched out from the through hole enters the tubular member. In this way, since the seal plate is punched only by the shaft-like member, a high degree of design freedom can be secured for the outer diameter of the seal plate and the inner diameter of the tubular member.

According to the present invention, a plurality of convex portions extending in the axial direction are formed on the outer peripheral surface of the shaft-shaped member, and a concave portion having a convex portion and a tightening margin is formed on the inner peripheral surface of the inner joint member. The vehicle is provided with an uneven fitting portion in which the entire fitting contact portion between the convex portion and the concave portion is in close contact by press-fitting into the inner joint member and transferring the shape of the convex portion to the concave portion forming surface of the inner joint member. When an axial load is applied at the time of collision, stable axial strength can be ensured.

Further, the axial member can be displaced in the axial direction with respect to the inner joint member by an axial load larger than the joining force at the concave-convex fitting portion, so that the buffer mechanism for absorbing the axial load at the time of a vehicle collision can be obtained. It becomes easy to increase the degree of design freedom. In this way, the design freedom of the constant velocity universal joint can be increased, so that a sliding type constant velocity universal joint equipped with a buffer mechanism that is easy to manufacture and highly reliable can be realized.

1 is a cross-sectional view showing the overall configuration of a double offset type constant velocity universal joint that is a sliding type constant velocity universal joint in an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. It is an expanded sectional view which shows the X section of FIG. It is sectional drawing which shows the state which the cage of FIG. 1 contact | abutted to the bottom part of the outer joint member. It is sectional drawing which shows the state which the shaft punched the seal plate from the state of FIG. It is sectional drawing which shows the state which the inner side coupling member of FIG. 1 contact | abutted to the bottom part of the outer side coupling member. It is sectional drawing which shows the state which the shaft pierced the seal plate from the state of FIG.

Embodiments of a sliding type constant velocity universal joint according to the present invention will be described in detail below with reference to the drawings.

In the following embodiment, for example, a ball type double offset constant velocity universal joint (DOJ), which is one of sliding constant velocity universal joints incorporated in an automobile propeller shaft, will be exemplified. The present invention can also be applied to a roller type tripod type constant velocity universal joint (TJ) as another sliding type constant velocity universal joint.

Propeller shafts built into automobiles are equipped with sliding constant velocity universal joints in order to have a structure that can handle axial displacement and angular displacement due to relative position changes between the transmission and the differential. The propeller shaft is configured by a combination of a sliding constant velocity universal joint and a steel tubular member, and is attached to the vehicle substantially parallel to the vehicle traveling direction.

A sliding type constant velocity universal joint (hereinafter simply referred to as a constant velocity universal joint) of this embodiment includes a cup-shaped outer joint member 11, an inner joint member 12, and a plurality of balls 13 as shown in FIG. And a cage 14, and a shaft 15, which is an axial member that extends from the inner joint member 12 and protrudes from the opening of the outer joint member 11, is coupled to the inner joint member 12.

In the outer joint member 11, linear track grooves 16 extending in the axial direction are formed at equal intervals in a plurality of locations in the circumferential direction of the cylindrical inner peripheral surface 17. The inner joint member 12 is paired with the track groove 16 of the outer joint member 11, and linear track grooves 18 are formed at a plurality of positions in the circumferential direction of the spherical outer peripheral surface 19 at equal intervals.

The ball 13 is interposed between the track groove 16 of the outer joint member 11 and the track groove 18 of the inner joint member 12. The ball 13 transmits rotational torque between the outer joint member 11 and the inner joint member 12. The cage 14 is interposed between the inner peripheral surface 17 of the outer joint member 11 and the outer peripheral surface 19 of the inner joint member 12. In the cage 14, a plurality of pockets 20 for holding the balls 13 are formed at equal intervals in a plurality of locations in the circumferential direction.

The shaft 15 is press-fitted into the shaft hole 21 of the inner joint member 12 and is connected to be able to transmit torque by an uneven fitting portion 45 described later. The inner joint member 12, the ball 13, and the cage 14 are accommodated in the outer joint member 11 and constitute internal components.

Also, an annular groove 22 is provided on the inner peripheral surface of the opening end of the outer joint member 11, and a circlip 23 is fitted into the annular groove 22. By such a retaining mechanism, when the internal component is displaced in the axial direction, the ball 13 interferes with the circlip 23, thereby restricting the axial displacement amount of the internal component to prevent the slide over.

In the constant velocity universal joint configured as described above, when an operating angle is provided between the outer joint member 11 and the inner joint member 12 by the shaft 15, the ball 13 held by the cage 14 is always at any operating angle. The operating angle is maintained within the bisectoral plane, and constant velocity between the outer joint member 11 and the inner joint member 12 is ensured. Between the outer joint member 11 and the inner joint member 12, rotational torque is transmitted via the balls 13 in a state where constant velocity is ensured.

In this constant velocity universal joint, a lubricant is enclosed in the inner space of the outer joint member 11, so that the sliding portion inside the joint is operated when the shaft 15 rotates while taking an operating angle with respect to the outer joint member 11. The lubricity is ensured at On the other hand, the constant velocity universal joint has a sealing mechanism between the opening end of the outer joint member 11 and the shaft 15 in order to prevent leakage of the lubricant enclosed in the joint and prevent foreign matter from entering from the outside of the joint. A structure in which the seal plate 25 is attached to the bottom 24 of the outer joint member 11 is provided.

The seal mechanism includes a boot 26 made of resin or rubber and a boot adapter 27 made of metal. The boot 26 has a small-diameter end portion 28 and a large-diameter end portion 29, and has a shape that is folded back into a U shape in the middle. The boot adapter 27 has a substantially cylindrical shape, and the base end portion 30 is fitted to the outer peripheral surface of the open end portion of the outer joint member 11. The large-diameter end portion 29 of the boot 26 is held by being crimped to the distal end portion 31 of the boot adapter 27. The small-diameter end portion 28 of the boot 26 is fastened and fixed to the outer peripheral surface of the shaft 15 by a boot band 32.

On the other hand, the seal plate 25 is a metal member in which a flange portion 34 is integrally formed at the opening end portion of the bottomed cylindrical portion 33. The seal plate 25 is attached so as to close the through hole 35 formed in the bottom 24 of the outer joint member 11. That is, the bottomed cylindrical portion 33 of the seal plate 25 is fitted into the through hole 35 and the flange portion 34 is brought into contact with the outer end surface of the bottom portion 24. By adopting such a structure, the seal plate 25 is attached to the bottom 24 so as to be detachable to the outside in the axial direction (right side in the drawing).

Furthermore, the bottom 24 of the outer joint member 11 is extended in the axial direction, and a steel tubular member 37 is coaxially connected and fixed to the extended end portion 36 by joining such as friction welding or arc welding. In FIG. 1, the case where the tubular member 37 is connected by friction welding is illustrated. A curled portion 38 is formed by friction welding at a joint portion between the extended end portion 36 of the outer joint member 11 and the tubular member 37. The tubular member 37 may have a structure connected by flange bonding.

In the constant velocity universal joint according to the embodiment shown in FIG. 1, the inner joint member 12 and the shaft 15 are coupled by the following structure. 2 is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 3 is an enlarged view of a portion X in FIG.

2 and 3, a male spline including a plurality of convex portions 40 extending in the axial direction is formed on the outer peripheral surface of the shaft end portion 39 of the shaft 15. On the other hand, a plurality of concave portions 41 (see the broken lines in FIG. 3) having a fastening allowance n with respect to the above-described convex portion 40 are arranged at equal intervals in the circumferential direction on the inner peripheral surface of the shaft hole 21 of the inner joint member 12. Form.

Here, the circumferential dimension of the concave portion 41 is set smaller than that of the convex portion 40. Thereby, the recessed part 41 has the interference n with respect only to the circumferential side wall part 42 of the convex part 40. FIG. Further, the radial dimension of the concave portion 41 is set larger than that of the convex portion 40. As a result, there is a gap p between a portion of the convex portion 40 excluding the circumferential side wall portion 42, that is, between the radial tip portion 43 and the concave portion 41 of the convex portion 40.

In the structure as described above, the shaft end portion 39 of the shaft 15 is press-fitted into the shaft hole 21 of the inner joint member 12. By this press-fitting, the concave portion forming surface of the shaft hole 21 is cut slightly by the circumferential side wall portion 42 of the convex portion 40, and the slight plastic deformation and elasticity of the concave portion forming surface by the circumferential side wall portion 42 of the convex portion 40 are cut. Concomitantly with the deformation, a recess 44 is formed on the recess forming surface by transferring the shape of the circumferential side wall 42 of the protrusion 40. At this time, depending on the setting of the tightening allowance n, it is possible to perform press-fitting without cutting. When press-fitting by cutting, since chips are generated, a groove for storing the chips is provided in the shaft spline.

At this time, since the circumferential side wall portion 42 of the convex portion 40 bites into the concave portion forming surface, the inner diameter of the inner joint member 12 is slightly expanded, and the relative movement in the axial direction of the convex portion 40 is performed. Permissible. When the axial relative movement of the convex portion 40 stops, the shaft hole 21 of the inner joint member 12 is reduced in diameter to return to the original diameter. As a result, the concave / convex fitting portion 45 is formed in close contact with the entire fitting contact portion between the convex portion 40 and the concave portion 44.

In this way, the inner joint member 12 and the shaft 15 are joined and integrated. In the concave / convex fitting portion 45 described above, a concave portion 41 having a fastening allowance n is formed in advance at the press-fitted portion of the convex portion 40. Therefore, the shaft end 21 of the shaft 15 can be press-fitted into the shaft hole 21 of the inner joint member 12 with a small press-fit load, and the shaft 15 can be easily assembled to the inner joint member 12.

In the propeller shaft assembled with the constant velocity universal joint having the above configuration, the inner joint member 12 and the shaft 15 are joined by the concave / convex fitting portion 45 described above, and the joining force at the concave / convex fitting portion 45 is larger. The shaft 15 can be displaced in the axial direction with respect to the inner joint member 12 by the axial load.

As described above, the convex portion 40 is formed on the outer peripheral surface of the shaft end portion 39 of the shaft 15, and the convex portion 40 and the fastening allowance n (see FIG. 3) are provided on the inner peripheral surface of the shaft hole 21 of the inner joint member 12. By forming the recess 41, the shaft end 39 of the shaft 15 is press-fitted into the shaft hole 21 of the inner joint member 12, and the shape of the protrusion 40 is transferred to the recess forming surface of the inner joint member 12. As a result, the inner joint member 12 and the shaft 15 are stably joined in the axial direction by the joining force at the concave-convex fitting portion 45. Therefore, when an axial load is applied at the time of a vehicle collision, a stable axial strength can be ensured, and sufficient reliability is obtained.

When an axial load is applied at the time of the vehicle collision, as shown in FIG. 4, the internal parts including the inner joint member 12, the ball 13, and the cage 14 are displaced in the axial direction, and the cage 14 constituting the inner part becomes the outer joint. It contacts the bottom 24 of the member 11.

Here, when the axial load is larger than the joining force at the concave / convex fitting portion 45, the shaft 15 penetrates the shaft hole 21 of the inner joint member 12 as shown in FIG. The seal plate 25 is punched from the through hole 35. The seal plate 25 punched from the through hole 35 enters the tubular member 37. In such a form, the axial load at the time of a vehicle collision is absorbed. When the shaft 15 penetrates the shaft hole 21 of the inner joint member 12, the boot 26 is broken.

The joining force at the concave / convex fitting portion 45 can be easily adjusted by dimensional management such as a tightening allowance n (see FIG. 3) of the convex portion 40 with respect to the concave portion 41. By adjusting the joining force, it is possible to arbitrarily set the axial strength at the concave-convex fitting portion 45. Therefore, as shown in FIG. 4, the joining force at the concave / convex fitting portion 45 so that the shaft 15 does not penetrate the shaft hole 21 of the inner joint member 12 only by the cage 14 abutting against the bottom 24 of the outer joint member 11. It is also possible to raise.

As described above, when the joining force at the concave / convex fitting portion 45 is increased, as shown in FIG. 6, when an axial load is applied at the time of a vehicle collision, the cage 14 constituting the internal component is connected to the outer joint member 11. The inner joint member 12 comes into contact with the bottom 24 of the outer joint member 11 after coming into contact with the bottom 24 and being damaged.

By increasing the joining force at the concave / convex fitting portion 45 until this state is reached, the shaft 15 penetrates the shaft hole 21 of the inner joint member 12 as shown in FIG. 39 punches the seal plate 25 from the through hole 35. The seal plate 25 punched from the through hole 35 enters the tubular member 37. Even in such a configuration, an axial load at the time of a vehicle collision can be absorbed. When the shaft 15 penetrates the shaft hole 21 of the inner joint member 12, the boot 26 is broken.

As described above, the inner joint member 12 and the shaft 15 are joined by the concave / convex fitting portion 45, and the shaft 15 is attached to the inner joint member 12 by an axial load larger than the joining force at the concave / convex fitting portion 45. Since the shaft can be displaced in the axial direction, it is possible to ensure stable axial strength when an axial load is applied during a vehicle collision. Therefore, it is possible to design a buffer mechanism that absorbs the axial load during a vehicle collision. It becomes easy to increase the degree.

Furthermore, this buffering mechanism increases the degree of freedom in designing a constant velocity universal joint in that a retaining mechanism such as a retaining ring for retaining the shaft 15 from the inner joint member 12 is not required as in the prior art. Can do.

In this constant velocity universal joint, a through hole 35 that is larger than the outer diameter of the shaft end portion 39 of the shaft 15 and smaller than the outer diameter of the inner joint member 12 is formed in the bottom 24 of the outer joint member 11, and A buffer mechanism is provided in which the seal plate 25 is fitted in the through hole 35. The inner diameter of the through hole 35 may be larger than the outer diameter of the shaft end portion 39 of the shaft 15 and smaller than the outer diameter of the inner joint member 12, and the value is arbitrary.

By adopting such a buffer mechanism, when an axial load is applied at the time of a vehicle collision, only the shaft 15 that is axially displaced with respect to the inner joint member 12 punches the seal plate 25 from the through hole 35. . Therefore, the outer diameter of the seal plate 25 can be made smaller than before. Thus, the degree of freedom in designing the seal plate 25 can be increased.

The outer diameter from the shaft end portion 39 of the shaft 15 to the mounting portion of the boot 26 is made smaller than the inner diameter of the shaft hole 21 of the inner joint member 12, and the axial dimension of the shaft 15 is lengthened to thereby increase the axial direction of the shaft 15. It is possible to provide a buffer mechanism that can increase the displacement and can sufficiently absorb the axial load at the time of a vehicle collision.

Further, the seal plate 25 punched out from the through hole 35 by the shaft 15 enters the tubular member 37. Thus, since the outer diameter of the seal plate 25 punched out only by the shaft 15 can be made smaller than before, a high degree of design freedom can be secured for the inner diameter of the tubular member 37 (curled portion 38 of the joining portion). Can do.

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

Claims (2)

A cup-shaped outer joint member, and an inner joint member accommodated in the outer joint member and transmitting torque while allowing axial displacement and angular displacement via the torque transmission member between the outer joint member, A sliding type constant velocity universal joint in which a shaft-like member is coupled to the inner joint member so as to transmit torque,
A plurality of convex portions extending in the axial direction are formed on the outer peripheral surface of the shaft-shaped member, and a concave portion having a tightening margin is formed on the inner peripheral surface of the inner joint member. By pressing into the concave joint forming surface of the inner joint member and transferring the shape of the convex portion to the concave portion forming surface of the inner joint member. A sliding type constant velocity universal joint characterized in that the axial member can be displaced in the axial direction with respect to the inner joint member by an axial load larger than the joining force. The bottom portion of the outer joint member forms a through hole that is larger than the outer diameter of the shaft-like member and smaller than the outer diameter of the inner joint member, and a seal plate is fitted into the through hole. The sliding-type constant velocity free according to claim 1, further comprising a structure in which a tubular member communicating with the tubular member is joined, wherein the axial displacement of the shaft-like member allows the seal plate to be detached from the through hole and enter the tubular member. Fittings.

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