JP2001082499A - Constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge substantial inside capacity of an outside joint material without changing the outside dimension of a constant velocity universal joint, and to promote the radiation of heat inside of the joint. SOLUTION: This universal joint is provided with an outside joint member 2 and a shank 3 for torque transmission constructed by different members, respectively. A cavity 4 communicating to the inside space of the outside joint member 2 is formed inside of the shank 3. The cavity 4 is formed penetrating to the tip of the shank 3 as the need arises. A flange 3a formed integrally at one end of the shank 3 is fitted externally or internally on the end wall of the outside joint member 2. The both members are unified either by contracting from outside or expanding from inside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ATV (All Terr
ain Vehicle: a constant velocity universal joint that can be used for a power transmission device of a saddle-ride type vehicle for traveling on uneven terrain or a general automobile.

[0002]

2. Description of the Related Art An ATV is a four-wheel or three-wheel saddle-ride type vehicle for traveling on uneven terrain, and is equipped with balloon tires so that it can freely travel on rough terrain or sandy beaches. In this ATV power transmission device, for example, as conceptually shown in FIG. 3, power of an engine 21 is output from an output shaft on a front side and a rear side via an internal speed change mechanism, and power transmission means such as a chain or a propeller shaft is provided. 22, 2
Front and rear differentials 2 through 3
4 and 25, respectively. Then, the engine power input to the differentials 24, 25 is reduced by the mechanism of the differentials 24, 25, further converted into rotational power in the right-angle direction, and transmitted to the wheels 28, 29 via the left and right drive shafts 26, 27. Is done.
In the example shown in FIG.
A constant velocity universal joint is used for a connection part A between the motor and the differential 24 and a connection part B for the wheel. still,
Drive shaft 27 on the rear side and differential 2
In some cases, a constant velocity universal joint is used for the connecting portion C to the wheel 5 and the connecting portion D to the wheel 29. When propeller shafts are used as the power transmission means 22 and 23, connecting portions E and F between the propeller shaft and the output shaft of the engine (transmission mechanism) 21, and connecting portions G and H between the differentials 24 and 25 are respectively provided. In some cases, a speed universal joint is used.

FIG. 4 shows a drive shaft 2 on the front side.
6 is shown. Following the movement of the wheel 28 at the time of cornering travel or rough terrain travel, the drive shaft 26 can be angularly displaced and axially displaced,
The connection of the drive shaft 26 includes a sliding type constant velocity universal joint (constant velocity universal joint permitting angular displacement and axial displacement between two axes) 30 and a fixed type constant velocity universal joint (angular displacement between two axes). Are used as a pair. In the example shown in the figure, one end of the drive shaft 26 is connected to a sliding constant velocity universal joint (double offset type constant velocity universal joint) 30.
Is connected to the differential 24 via (connection part A),
The other end of the drive shaft 26 is connected to a wheel 28 via a fixed type constant velocity universal joint (zepper type constant velocity universal joint: ball fixed joint) 31 (connection part B).

FIG. 5 shows a connecting portion A between one end of the drive shaft 26 and the differential 24. One end of the drive shaft 26 is serrated (or spline-fitted) to the inner joint member 32 of the sliding constant velocity universal joint 30, and the outer joint member 33 of the sliding constant velocity universal joint 30 is fitted.
Shaft part 33a is the differential case 3 of the differential 24.
4 and the boss 3 of the differential gear case 35
5a, serration fit (or spline fit) with the side gear 36. The opening 34a of the differential case 34, the boss 35a of the differential gear case 35, and the differential gear case 35 (and the outer joint member 33) are attached to the outer diameter of the shaft portion 33a of the outer joint member 33.
Bearing 37 rotatably supported with respect to the oil seal 3 for sealing the opening 34a of the differential case 34
8 are arranged.

[0005] The power from the engine 21 is input to a drive pinion gear (not shown) of the differential 24, and the drive pinion gear → a ring gear (not shown) →
The power is transmitted to the wheel 28 through the path of the differential gear case 35 → pinion gear (not shown) → side gear 36 → slidable constant velocity universal joint 30 → drive shaft 26 → fixed constant velocity universal joint 31.

[0006]

The power transmission device of the ATV follows the large movement of the wheel at the time of running on rough terrain or the like. Therefore, the angular displacement and the axial direction of the drive shaft coupling constant velocity universal joint are larger than those of a passenger car or the like. Large displacement. It is desirable that the angular displacement and the axial displacement be as small as possible for the durability of the constant velocity universal joint. Therefore, the amount of angular displacement and the amount of axial displacement are suppressed by increasing the length of the drive shaft. For example, the sliding constant velocity universal joint 3 shown in FIG.
Even if it is 0, the position of the ball is arranged as close to the differential 24 as possible. For this reason, the size of the internal space of the outer joint member 33 tends to be suppressed to a necessary minimum.

However, the inner space of the outer joint member 33 is filled with lubricating grease. If the inner volume of the outer joint member 33 is small, the amount of lubricating grease and the heat radiation area thereof are also restricted. Therefore, the grease temperature during running tends to be relatively high. When the grease temperature becomes high, the quality of the grease deteriorates in a relatively short period of time, leading to poor lubrication, which may lead to a reduction in the life of the constant velocity universal joint.

An object of the present invention is to increase the substantial internal volume of the outer joint member without changing the external dimensions of the constant velocity universal joint, thereby promoting heat radiation inside the joint.

[0009]

To solve the above-mentioned problems, a constant velocity universal joint according to the present invention comprises an outer joint member having a plurality of guide grooves on an inner peripheral portion and an inner joint member having a plurality of guide grooves on an outer peripheral portion. A joint member, a torque transmission ball disposed on each of a plurality of ball tracks formed by opposing guide grooves of the outer joint member and the inner joint member, and a retainer for holding the torque transmission ball. The speed universal joint is characterized in that a hollow portion communicating with the internal space of the outer joint member is formed inside a shaft portion that is integrally connected to the outer joint member and transmits torque.

[0010] When the hollow portion communicating with the internal space of the outer joint member is formed inside the shaft portion as described above, the heat radiation area of the internal space increases by that much, and the heat radiation effect by the flow of air increases. Temperature rise can be suppressed, and the life of the constant velocity universal joint can be increased.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Two embodiments of the present invention will be described below with reference to FIGS. FIG. 1 and FIG.
1 shows a sliding type constant velocity universal joint 1A, 1B connected to a front differential of a TV, wherein each of the sliding type constant velocity universal joints 1A, 1B is integral with an outer joint member 2 and is a differential side gear; A hollow portion 4 is formed in the shaft portion 3 which is serrated or spline-fitted to communicate the internal space of the outer joint member 2 with the internal space of the differential gear case.

Referring first to the sliding type constant velocity universal joint 1A in FIG. 1, six linear guide grooves 6 are formed in the inner surface 5 of the cylindrical outer joint member 2 in the axial direction. Six linear guide grooves 9 are also formed in the spherical outer diameter surface 8 of the inner joint member 7 in the axial direction. Six torque transmitting balls 12 are arranged on a ball track formed by the guide groove 6 of the outer joint member 2 and the guide groove 9 of the inner joint member 7 facing each other. These torque transmission balls 12 are held by a holder 13. A serration (or spline) 14 for connecting one end of the drive shaft 26 is provided on the inner surface of the inner joint member 7.
A rubber boot 10 is mounted between the one end opening of the outer joint member 2 and the outer peripheral surface of the drive shaft 26.

The retainer 13 is provided on the inner surface 5 of the outer joint member 2.
Spherical outer surface 13a guided in contact with the inner surface, and spherical inner surface 13b in contact with the outer surface 8 of the inner joint member 7
And six pockets 1 for accommodating the torque transmitting ball 12
3c. Then, the center of the spherical surface of the outer diameter surface 13a and the center of the spherical surface of the inner diameter surface 13b on the axis of the drive shaft 26 are offset by the same distance in the axial direction from the center of the pocket 13c (double). Offset structure). This double offset structure is such that when the outer joint member 2 and the inner joint member 7 are angularly displaced by an arbitrary angle θ, the torque transmission ball 12 guided by the retainer 13 always has a bisecting plane (θ /
This is intended to be maintained in 2), whereby the uniform velocity of the joint 1A is ensured. The radius of curvature of the inner diameter surface 13b of the retainer 13 and the radius of curvature of the outer diameter surface 8 of the inner joint member 7 are substantially the same (apparently equal), and the axial dimension of the pocket 13c of the retainer 13 is torque transmission. The diameter is slightly smaller than the diameter of the ball 12.

The above-mentioned inner and outer joint members 2, 7 and the retainer 13
Is similar to a conventional sliding type constant velocity universal joint and is not particularly new. A novel feature of the constant velocity universal joint 1A according to the first embodiment is that a hollow portion 4 communicating with the internal space of the outer joint member 2 is formed inside the torque transmitting shaft portion 3 integrated with the outer joint member 2. That is, the outer joint member 2 and the shaft portion 3 are formed as separate members, and the flange portion 3 a formed at one end of the shaft portion 3 is internally fitted to the inner peripheral wall of the end portion of the outer joint member 2. Specifically, as shown in FIG.
The cavity 4 allows the internal space of the outer joint member 2 to communicate with the internal space of the differential gear case. In addition, an annular concave portion 15 is formed in the inner circumferential wall at the end portion of the outer joint member 2 along the circumferential direction. An annular convex portion 16 along the circumferential direction for increasing the tensile strength in the axial direction is provided between the concave portions 15. Is formed. The outer diameter surface of the flange portion 3a is fitted to the concave portion 15. After the flange portion 3a is fitted to the outer joint member 2, the outer diameter surface of the outer joint member 2 is formed by, for example, drawing. The projections 16 are cut into the outer diameter surface of the flange portion 3a to integrate them. In order to increase the bonding strength between the two by drawing, the surface hardness of the flange 3a on the male side should be slightly higher than the surface hardness of the peripheral wall of the end of the outer joint member 2 on the female side. desirable. Further, a circumferential groove having an appropriate depth may be formed on the outer diameter surface of the flange portion 3a in order to easily penetrate the convex portion 16 and increase the strength in the axial direction.

Next, the sliding type constant velocity universal joint 1B of FIG. 2 according to the second embodiment will be described. The structures of the inner and outer joint members 2, 7 and the retainer 13 are completely the same as those of the first embodiment of FIG. The same and different parts are only the fitting structure of the flange 3a to the peripheral wall at the end of the outer joint member 2. That is, in the second embodiment, the outer joint member 2
A concave portion 17 is formed on the outer peripheral wall of the end along the circumferential direction,
The concave portion 18 formed on the inner diameter surface of the flange portion 3a is configured to fit into the concave portion 17 of the outer joint member 2. A convex portion 19 is formed along the circumferential direction at the tip of the concave portion 18 of the flange portion 3a, and the convex portion 19 is formed by, for example, drawing the outer diameter surface of the flange portion 3a. And the two are integrated. Also in the second embodiment, in order to increase the bonding strength between the two by drawing, the surface hardness of the peripheral wall of the end of the outer joint member 2 on the male side is larger than the surface hardness of the flange 3a on the female side. Is desirably set slightly higher. Further, a circumferential groove having an appropriate depth may be formed in the outer peripheral wall at the end of the outer joint member 2 so that the convex portion 19 can easily bite and enhance the strength in the axial direction.

In the above two embodiments, the inner space of the outer joint member 2 is communicated with the inner space of the differential gear case 35 of FIG. The heat inside 2 is also radiated from the hollow portion 4 or the shaft portion 3 and has an effect of suppressing a rise in the temperature of the grease.

Although the two embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications are possible. For example, in the above embodiments, the outer diameter of the outer joint member 2 is The surface or the outer diameter surface of the flange portion 3a was drawn and the two were plastically connected.
The inner diameter surface of a or the inner diameter surface of the outer joint member 2 in FIG. 2 may be expanded to be integrated by plastic bonding, and furthermore, the plastic bonding portion may be hardened by using high-frequency heating or the like. Welding may be performed. In addition, the unevenness formed on the fitting surface between the outer joint member 2 and the flange portion 3a may be formed on one or both of them. The irregularities can be formed by applying, for example, a spline, a screw, or a knurling process of about module 1 to the outer diameter surface of the flange portion 3a of FIG. 1 which is the male side or the outer peripheral wall of the end of the outer joint member 2 of FIG. it can. At this time, the counterpart female side may remain cylindrical.

The torque transmitting shaft 3 may be formed by, for example, forming a steel tubular member by cold forging, or by narrowing a steel pipe member. Further, for example, when it is necessary to fill the inner space of the outer joint member 2 and the inner space of the differential gear case 35 with different types of grease, the hollow portion 4 does not penetrate to the tip of the shaft portion 3 and does not penetrate. 3 may be formed halfway, or the tip of the rear shaft portion 3 formed through the hollow portion 4 may be closed with a plug. In addition, although each of the above embodiments relates to a sliding type constant velocity universal joint, the present invention is also applicable to a fixed type constant velocity universal joint, in which case the hollow portion 4 is formed inside an axle. Will do. Further, the present invention can be applied not only to ATVs but also to power transmission devices for general automobiles.

[0019]

As described above, according to the present invention, a cavity communicating with the internal space of the outer joint member is formed inside the torque transmitting shaft integrated with the outer joint member. The space is substantially increased by the cavity, the heat radiation area is increased by the cavity, and the heat radiation effect by the flow of air increases, so that the grease temperature rise can be suppressed,
As a result, the life of the constant velocity universal joint can be improved. In addition, since the constant velocity universal joint can be reduced in weight by the amount of the cavity, it is also useful for improving fuel efficiency.

Further, the shaft portion of the outer joint member can be formed as a separate member, so that an optimum material can be selected according to the function of each part. For example, when the shaft portion is the weakest portion, the shaft portion can be replaced with a high-strength material to increase the strength, or the shaft portion can be made of aluminum for weight reduction. In addition, the shaft portion is separated, and the internal design of the cup portion of the outer joint member is shared, so that the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a sliding type constant velocity universal joint according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a sliding type constant velocity universal joint according to a second embodiment of the present invention.

FIG. 3 is a schematic plan view of an ATV power transmission device.

FIG. 4 is a side view of the drive shaft on the front side.

FIG. 5 is a sectional view of a connecting portion between one end of a drive shaft and a differential.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1A, 1B Sliding constant velocity universal joint 2 Outer joint member 3 Torque transmitting shaft part 3a Flange part 4 Cavity part 7 Inner joint member 10 Boot 12 Torque transmitting ball 13 Cage 15 Concave part 16 Convex part 17 Concave part 18 Concave part 19 Convex Part 24 differential 26 drive shaft

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Kato 1578 Higashikaizuka, Iwata-shi, Shizuoka F-term (reference) 4E087 AA10 BA18 CA13 CA21 CA33 CB03 DB11 DB14 HA21 HA24

Claims (6)

[Claims] An outer joint member having a plurality of guide grooves on an inner peripheral portion, an inner joint member having a plurality of guide grooves on an outer peripheral portion,
A constant velocity universal joint comprising: a torque transmission ball disposed on each of a plurality of ball tracks formed by opposing guide grooves of the outer joint member and the inner joint member; and a retainer holding the torque transmission ball. A constant velocity universal joint, wherein a hollow portion communicating with an internal space of the outer joint member is formed inside a shaft portion that transmits torque by being integrally connected to the outer joint member. 2. An end of the shaft portion is integrally formed with a flange portion which can be fitted to an end peripheral wall of the outer joint member by external fitting or internal fitting, and the flange portion and / or the outer joint member is The constant velocity universal joint according to claim 1, wherein the fitting surfaces are plastically connected by forming irregularities on the fitting surface and expanding or reducing the diameter of one of the fitting surfaces. 3. The constant velocity universal joint according to claim 2, wherein said shaft portion is formed by cold forging of a steel tubular member. 4. The constant velocity universal joint according to claim 2, wherein said shaft portion is formed by drawing a steel pipe member. 5. The constant velocity universal joint according to claim 2, wherein a hardening treatment by heat treatment is applied to said joint. 6. The constant velocity universal joint according to claim 2, wherein an end of said plastic joint is welded.