JP2583634Y2 - Automotive tripod type constant velocity joint - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a tripod type constant velocity joint for an automobile which is incorporated in a drive system of an automobile and is used for transmitting a rotational driving force between non-linear rotating shafts. I do.

[0002]

2. Description of the Related Art In the case of a front-engine front-wheel drive vehicle (FF vehicle), the front wheels are often of an independent suspension type, and a relatively large angle is formed between the wheel-side rotation shaft and the engine-side rotation shaft. . Therefore, irrespective of such bending, the rotation driving force is evenly transmitted between the two rotation shafts (the rotation angular velocity does not change with rotation), and the operation of the vehicle is performed smoothly. For this purpose, the two rotating shafts are connected to each other via a constant velocity joint.

For this reason, conventionally, for example, Japanese Patent Application Laid-Open No. 2-286
The ends of a pair of rotating shafts that do not exist on the same straight line are connected to each other by using a constant velocity joint as described in JP-A-920. This constant velocity joint comprises a tripod 1 as shown in FIGS. 1 and 2 and a housing 2 as shown in FIGS. 4 to 5 through rollers 3, 3, a spherical roller 4, and a cylindrical roller 5 as shown in FIG. It is composed by combining as shown. Of these, the housing 2 is formed in a hollow cylindrical shape with one end opened, and is fixed to an end of one of a pair of rotating shafts to transmit a rotating force to each other. Concave portions 6 are formed at three positions on the inner peripheral surface of the housing 2 at regular intervals in the radial direction. The inner surfaces 7, 7 of the recesses 6, 6 are flat surfaces parallel to the diameter direction of the housing 2, respectively.

On the other hand, the tripod 1 fixed to the end of the other rotating shaft of the pair of rotating shafts is provided on the outer peripheral surface of a boss 8 for fixing to the end of the other rotating shaft. Are fixedly provided with three trunnions 9, 9 that enter the three recesses 6, 6 formed in the housing 2. A locking groove 11 for fitting a locking ring 10 is formed on the outer peripheral surface of each trunnion 9, 9 formed in a short columnar shape over the entire circumference. A spherical roller 4 is rotatably supported around the three trunnions 9 via a plurality of rollers 3, 3, respectively. The spherical roller 4 formed entirely in a ring shape has an inner peripheral surface 13 as a cylindrical surface and an outer peripheral surface 14 as a spherical convex surface centered on a point on the center line of the trunnion 9. As described above, the annular guide ring 15 is externally fitted to the tip of the trunnion 9 which rotatably supports the spherical roller 4 via the plurality of rollers 3 and 3. The guide ring 15 is prevented from falling out of the trunnion 9 by fitting the lock ring 10 into the lock groove 11 located closer to the distal end than the guide ring 15.

Further, a cylindrical roller 5 is externally fitted and supported on the outside of the spherical roller 4 rotatably supported on the outside of the trunnion 9 as described above. The cylindrical roller 5, which is entirely formed in an annular shape, has an outer peripheral surface 16 that
A pair of raceway surfaces 17, 1 provided in the concave portions 6, 6 of the inner peripheral surface of
7 (FIGS. 4 and 5), and the inner peripheral surface 18 is
The spherical roller 4 has a spherical concave surface that is in sliding contact with the outer peripheral surface 14. As shown in FIG. 3, a pair of grooves 19, 19 through which the spherical roller 4 can pass is formed at a position diametrically opposite to the opening edge of the one end surface of the cylindrical roller 5.
The spherical roller 4 having a spherical convex surface 4 and the cylindrical roller 5 having an inner peripheral surface 18 having a spherical concave surface can be freely combined.

When the two rollers 4 and 5 are combined with each other so that the spherical roller 4 exists inside the cylindrical roller 5 as shown in FIGS. 1 and 2, first, as shown in FIG. The rollers 4 and 5 are brought closer to each other while the central axes of the rollers 5 and 5 are shifted from each other by 90 degrees. Then, both ends in the diameter direction of the spherical roller 4 are passed through the inside of the insertion grooves 19 formed on the opening edge of the cylindrical roller 5. In this way, when the diametrical ends of the spherical roller 4 are passed through the grooves 19, 19 and the spherical roller 4 is positioned inside the cylindrical roller 5, the grooves 19, 19 are formed.
The spherical roller 4 is rotated by 90 degrees around the diameter in the direction connecting. Thus, the spherical roller 4 and the cylindrical roller 5 are combined in the state shown in FIGS. Accordingly, the length L of each of the grooves 19 in the circumferential direction is equal to or greater than the thickness T of the spherical roller 4 (L ≧ T).

When transmitting a rotational force between a pair of rotating shafts by means of a tripod-type constant velocity joint for an automobile configured as described above, for example, a driving-side rotating shaft having one end coupled and fixed to a housing 2 is rotated. Then, the rotational force is transmitted from the housing 2 to the boss 8 of the tripod 1 via the cylindrical roller 5, the spherical roller 4, the plurality of rollers 3 and 3, and the trunnion 9. Then, the driven-side rotating shaft with the boss 8 fixed to the end is rotated at the same speed as the driving-side rotating shaft. When the pair of rotation shafts are not located on a straight line and the center axis of the tripod 1 and the center axis of the housing 2 are bent, each cylindrical roller 5 is displaced on the raceway surface 17. By doing so, this bending is allowed.

[0008]

However, in the case of a conventional tripod type constant velocity joint for an automobile constructed and operated as described above, the following problems occur. That is,
When transmitting a rotational force between a pair of rotating shafts, the outer circumferential surface 16 of the cylindrical roller 5
As a result, as shown in FIG. 6, a strong force F for pressing the outer peripheral surface 16 inward in the diametrical direction is applied. On the other hand, the cylindrical roller 5 and the spherical roller 4
Are formed so as to combine the grooves 1 and 2 with each other.
As shown in FIG. 7, there is a moment when the surfaces 9 and 19 face the track surfaces 17 and 17.

The outer peripheral surface 14 of the spherical roller 4 and the inner peripheral surface 18 of the cylindrical roller 5 are separated from each other in the grooves 19, 19, and the force F cannot be supported in the grooves 19. Therefore, as described above, the groove 19 is formed on the raceway surface 17.
When the groove 1 is opposed to the groove 1, as shown by an arrow in FIG.
The force F is supported in the vicinity of both end portions of the reference numeral 9. The material is fatigued by being repeatedly elastically deformed around the central portion A in the circumferential direction of the insertion groove 19, so that the material is easily damaged relatively early. Of course, by increasing the thickness of the cylindrical roller 5 to reduce the amount of elastic deformation, damage due to fatigue of the material can be made less likely to occur, but instead, the tripod type constant velocity joint for automobiles becomes larger, It is inevitable that the weight will increase. The automotive tripod constant velocity joint of the present invention was invented in view of the above-described circumstances.

[0010]

The tripod-type constant velocity joint for a vehicle according to the present invention has a pair of flat surfaces each parallel to the diameter direction of the housing, similarly to the above-mentioned conventional tripod-type constant velocity joint for a vehicle. Three concave portions having a raceway surface are provided at equal intervals on the inner peripheral surface, and a hollow cylindrical housing fixed to the end of the first rotating shaft and enters into the three concave portions of the housing. Three trunnions are fixed on the outer peripheral surface, and a tripod fixed to the end of the second rotating shaft and a spherical convex surface on the outer peripheral surface are rotatably mounted on the outer peripheral surfaces of the respective trunnions via roller bearings. The supported spherical roller and the outer peripheral surface are cylindrical surfaces that are in rolling contact with the pair of track surfaces,
An inner peripheral surface is formed as a spherical concave surface which is in sliding contact with the spherical convex surface, and is externally fitted to the spherical roller. The cylindrical roller has a groove for assembling the spherical roller at a position diametrically opposite the inner peripheral surface.

In particular, in the tripod constant velocity joint for an automobile of the present invention, the width dimension w of the groove in the axial direction of the cylindrical roller is set to be less than 1/2 of the width dimension W of the cylindrical roller. And a straight line connecting the center of the spherical convex surface and the spherical concave surface and the inner edge of the groove is defined as a, and a straight line passing through the center and orthogonal to the trunnion axis is defined as b. Angle α between these straight lines a and b
Is set to 4 times or more.

[0012]

The operation of transmitting the rotational force between the first and second rotating shafts by the tripod-type constant velocity joint for an automobile of the present invention constructed as described above is the same as the conventional operation described above. This is almost the same as the tripod type constant velocity joint. In particular, in the case of the tripod-type constant velocity joint for automobiles of the present invention, since the portion for forming the groove is limited, the groove is opposed to the raceway surface of the housing, and a cylinder is formed from the raceway surface. Even when a strong force is applied to the roller, the inner peripheral surface of the cylindrical roller and the outer peripheral surface of the spherical roller abut on a sufficiently large area of the central portion of the force applied to the cylindrical roller. In addition, the width w of the groove in the axial direction of the cylindrical roller is set to less than 1/2 of the width W of the cylindrical roller, and the center of the spherical convex surface and the spherical concave surface and the inner edge of the groove are formed. And a straight line passing through the center and perpendicular to the axis of the trunnion is defined as b.
Is 4 degrees or more, the widthwise central portion of the inner peripheral surface of the cylindrical roller contacts the outer peripheral surface of the spherical roller. As a result, the spherical roller supports the radially inward force applied to the outer peripheral surface of the cylindrical roller in the width direction in a well-balanced manner. For this reason, the amount of elastic deformation of the cylindrical roller forming portion is reduced, and the cylindrical roller is less likely to be damaged.

[0013]

Next, an experiment performed by the present inventors to confirm the effects of the present invention will be described. The tripod type constant velocity joint for a vehicle of the present invention is configured as shown in FIGS. Except for the dimensions of the grooves 19, 19 formed in the inner peripheral surface 18 of the cylindrical roller 5, the shapes and the like of the respective members are the same as those of the above-described conventional tripod type constant velocity joint for automobiles. The reference numerals are given and duplicate description is omitted.

In the tripod type constant velocity joint for an automobile according to the present invention, the width dimension w of each of the grooves 19, 19 extending in the axial direction of the cylindrical roller 5 is preferably set to one of the width dimension W of the cylindrical roller 5. / 2 (w <W / 2). At the same time, a straight line connecting the center o of the spherical convex surface formed on the outer peripheral surface 14 of the spherical roller 4 and the spherical concave surface formed on the inner peripheral surface 18 of the cylindrical roller 5 with the inner end edges of the above-mentioned grooves 19, a
When a straight line passing through the center o and perpendicular to the axis x of the trunnion 9 is defined as b, these straight lines a and b
Is made to be 4 degrees or more.

The upper limit of the angle α is designed in consideration of the material, diameter, thickness and the like of the rollers 4 and 5 so that the spherical roller 4 can be pushed inside the cylindrical roller 5. Determined by consideration. That is, as the degree α is increased, the amount of elastic deformation of the groove 19 of the cylindrical roller 5 is reduced so that the cylindrical roller 5 is less likely to be damaged. However, the following problem occurs. . That is, the width w of the grooves 19, 19 extending in the axial direction of the cylindrical roller 5 is set to less than 1/2 of the width W of the cylindrical roller 5, and the angle α is set to 4 degrees or more. The distance between the inner ends of the pair of receiving grooves 19 provided at two locations on the inner peripheral surface of the cylindrical roller 5 on the opposite side in the diameter direction is smaller than the outer diameter of the spherical roller 4. Therefore, when incorporating the spherical roller 4 inside the cylindrical roller 5, the cylindrical roller 5 is elastically deformed in a direction in which the inner diameter of the portion where the pair of receiving grooves 19, 19 is formed increases, while the cylindrical roller 5 is elastically deformed. It is necessary to push the spherical roller 4 inside the cylindrical roller 5. When the angle α is too large, the amount of elastic deformation of the cylindrical roller 5 when the spherical roller 4 is pushed into the cylindrical roller 5 in this manner increases. If the amount of elastic deformation is excessive, the rollers 4 and 5 may be damaged when the spherical roller 4 and the cylindrical roller 5 are combined, or in an extreme case, the combining operation itself cannot be performed. The upper limit value of the angle α is regulated in consideration of such matters. For example, in the case of a tripod-type constant velocity joint used in a state of being incorporated in a drive system of an automobile, the following aspects can be considered. That is, the rollers 4 and 5 were made of SUJ2, the hardness was HRC60, the outer diameter of the spherical roller 4 was 32 mm, the width was 15 mm, and the outer diameter of the cylindrical roller 5 was 42 mm and the width was 15 mm. In this case, the upper limit value of the angle α is about 5.5 degrees.

In order to confirm the effect of the tripod type constant velocity joint of the present invention in which the angle α is set to 4 degrees or more, as shown in FIG. The cylindrical roller 5 was held between the pressing members 21 and pressed between the members 20 and 21. As the test pieces, six kinds each of two kinds shown in the following Table 1 were used, a total of 12 pieces.

[0017]

[Table 1]

In the test, the grooves 19 formed on the inner peripheral surface of the cylindrical roller 5 were arranged on a straight line connecting the base 20 and the pressing piece 21 as shown in FIG. The cylindrical roller 5 was pressed until it was partially broken, and the breaking strength was determined by the load (ton) at the time of the breakage. Of the twelve test pieces, six test pieces were measured for breaking strength with the cylindrical roller 5 alone without forming a tripod-type constant velocity joint. The result is shown in FIG. The vertical axis position of the black point in FIG. 10 (A) represents the magnitude of the load applied to the cylindrical roller 5 at the moment when a part of the cylindrical roller 5 as a test piece is broken. I have. Then, from the test results shown in FIG.
When the angle α is 4 degrees or more (test piece number 2),
It can be seen that the breaking strength of the cylindrical roller 5 alone hardly changes when the temperature is set to 4 degrees or less (test piece number 1).

Next, the same test was performed on the remaining six test pieces in a state where they were assembled as a tripod type constant velocity joint. The results of this test are shown in Table 2 below and FIG.
It is shown in (B).

[0020]

[Table 2]

According to the test results, when the angle α is 4 degrees or more, the breaking strength of the cylindrical roller 5 is improved when the spherical roller 4 and the cylindrical roller 5 are assembled to a tripod-type constant velocity joint. I understand. Further, as shown in Table 1 above, in a standard durability test in a state of being assembled to a tripod type constant velocity joint, if the angle α was 4 degrees or more, the test passed. However, those with 2.5 degrees were rejected.

[0022]

[Effects of the Invention] As described above, the present invention improves the breaking strength of a cylindrical roller, prevents a failure due to the breakage of the cylindrical roller, and has an excellent durability and reliability. Speed joint can be realized.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a tripod type constant velocity joint for an automobile according to the present invention, excluding a housing.

FIG. 2 is an essential part cross-sectional view showing a state where the housing is combined with a housing.

FIG. 3 is an exploded perspective view showing a state where a spherical roller and a cylindrical roller are combined.

FIG. 4 is an end view of the housing.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a diagram for explaining a force applied to a cylindrical roller during use.

FIG. 7 is a view as seen from above in FIG. 6;

FIG. 8 is a view showing only a cylindrical roller taken out of the state of FIG. 7;

FIG. 9 is a diagram showing a state of a breaking strength test.

FIG. 10 is a graph showing the results of a breaking strength test.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tripod 2 Housing 3 Roller 4 Spherical roller 5 Cylindrical roller 6 Concave part 7 Inner side surface 8 Boss part 9 Trunnion 10 Locking ring 11 Locking groove 13 Inner peripheral surface 14 Outer peripheral surface 15 Guide ring 16 Outer peripheral surface 17 Track surface 18 Inner peripheral surface 19 groove 20 base 21 pressing piece

Claims (1)

(57) [Scope of request for utility model registration] 1. Three recesses each having a pair of flat track surfaces parallel to a diameter direction of a housing are provided at equal intervals on an inner peripheral surface, and are fixed to an end of a first rotating shaft. A hollow cylindrical housing, three trunnions that enter the three recesses of the housing are fixed to the outer peripheral surface, and a tripod fixed to the end of the second rotary shaft, and the outer peripheral surface are spherical. A spherical roller that is rotatably supported on the outer peripheral surface of each of the trunnions via a roller bearing, and a cylindrical surface that is in rolling contact with the pair of track surfaces, and an inner peripheral surface is the spherical convex surface. An automobile having a spherical concave surface that is in sliding contact with the spherical roller and externally fitted to the spherical roller, and a cylindrical roller having a groove for assembling the spherical roller at a position diametrically opposite the inner peripheral surface.
In the tripod type constant velocity joint for use, the width dimension w of the groove in the axial direction of the cylindrical roller is set to less than 1/2 of the width dimension W of the cylindrical roller, and the spherical convex surface and the spherical concave surface are formed. When a straight line connecting the center and the inner edge of the groove is a, and a straight line passing through the center and orthogonal to the axis of the trunnion is b, the angle α between the straight lines a and b is α. own, characterized in that it was 4 degrees higher
Tripod constant velocity joint for motor vehicles .