JP2006138348A - Tripod-type uniform universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent early breakage failure of a retainer acting as a component of a roller assembly in a tripod-type uniform universal joint. <P>SOLUTION: The roller assembly 30 of the tripod-type uniform universal joint comprises a roller 32 inserted in a freely rolling manner into a track groove 12 of an outside joint member 10, a ring 34 inserted externally into a leg shaft 22 of a tripod member 20 to support the roller 32 in a freely rolling manner, a plurality of balls 36 arrayed in a track between the roller 32 and the ring 34, a resin crown-shaped retainer 38 for holding the plurality of the balls 36 at predetermined intervals in a circumferential direction of the track. Further, the crown-shaped retainer 38 is arranged in a ring guiding method or in a roller guiding method. As a result, the crown-shaped retainer 38 is regulated from becoming deformed in its radial direction, thus being able to prevent the early breakage failure of the retainer 38. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is a kind of a sliding type constant velocity universal joint that couples two shafts on the driving side and the driven side and transmits torque at a constant speed while allowing angular displacement and relative axial displacement between the two shafts. The present invention relates to a tripod type constant velocity universal joint.

  A constant velocity universal joint is a kind of universal joint that connects two shafts on the driving side and the driven side and can transmit a rotational force at a constant speed even if there is an angle between the two shafts. The constant velocity universal joint includes a fixed type and a sliding type, and the sliding type enables relative axial displacement between two axes by plunging the joint. One type of sliding type is a tripod type.

  The tripod type constant velocity universal joint includes an outer joint member and a tripod member, and one of the two shafts to be coupled is connected to the outer joint member and the other is connected to the tripod member. The outer joint member has a bottomed cylindrical shape and has three track grooves extending in the axial direction on the inner periphery. The tripod member has three leg shafts protruding in the radial direction. Then, torque is transmitted by engaging the leg shaft of the tripod member in the track groove of the outer joint member.

  Non-Patent Document 1 shows the most basic tripod type constant velocity universal joint. In this tripod type constant velocity universal joint, a roller is fitted on each of three leg shafts of a tripod member, and a roller is interposed between the leg shaft and a track groove. Further, a slide bearing or a plurality of needle rollers disposed between a roller and a leg shaft is also disclosed.

  On the other hand, tripod type constant velocity universal joints include models as shown in FIGS. In FIG. 5, reference numeral 10 denotes an outer joint member, and reference numeral 20 denotes a tripod member. The outer joint member 10 has a bottomed cylindrical shape, has three track grooves 12 extending in the axial direction on the inner periphery, and roller guide surfaces 14 are formed on both side walls facing each other in the circumferential direction of each track groove 12. is there. The tripod member 20 has three leg shafts 22 projecting in the radial direction, and a roller assembly 30 is fitted on each leg shaft 22.

  This roller assembly 30 is a so-called double row deep groove ball bearing, and is accommodated in the track groove 12 of the outer joint member 10 and is externally attached to the roller 32 rolling on the roller guide surface 14 and the leg shaft 22 of the tripod member 20. The ring 34 is fitted and rotatably supports the roller 32, and the balls 36a and 36b are arranged in a double row between the roller 32 and the ring 34. The roller 32 in FIG. 5 has a two-part structure and is composed of a pair of roller portions 32a and 32b that are in contact with each other at a plane perpendicular to the axis. The outer peripheral surfaces of the roller portions 32a and 32b are partial spherical surfaces or partial annular surfaces. Track grooves 33a and 33b are provided on the inner circumferences of the roller portions 32a and 32b, respectively. The ring 34 in FIG. 5 has an annular shape, and its inner peripheral surface is a partial ring surface, and is loosely fitted to the elliptical columnar leg shaft 22 as shown in FIG. Two rows of raceway grooves 35a and 35b are provided on the outer periphery of the ring 34 so as to face the raceway grooves 33a and 33b of the roller portions 32a and 32b. The ball 36 is disposed on a track formed between the raceway grooves 33 a and 33 b of the roller portions 32 a and 32 b and the raceway grooves 35 a and 35 b of the ring 34. Here, as shown in FIG. 6, the balls are arranged in a total ball state in which as many balls 36 as possible are incorporated.

  When the balls 36 are arranged in a full ball state, the number of contact points between the rollers 32 and the ring 34 and the balls 36 increases, and the crushing strength of the roller assembly 30 is improved. In order to dispose the ball 36 in a full ball state, it is general to provide a groove for the ball 36 in the roller 32 and the ring 34. However, when the insertion groove is provided, the crushing strength of the roller 32 and the ring 34 is lowered. For this reason, in the tripod type constant velocity universal joint described above, the roller 32 has a two-part structure so that the ball 36 can be assembled without providing a groove. As this type of tripod type constant velocity universal joint, there is one disclosed in Patent Document 1, for example.

  On the other hand, there are types of deep groove ball bearings applicable as the roller assembly 30 as shown in FIGS. The roller assembly 30 includes a cage 38 that holds the balls 36 at a predetermined interval in the track circumferential direction. If a gap is provided between the balls 36 by the retainer 38, the number of balls 36 that can be incorporated is reduced and the surface pressure applied to the roller 32 and the ring 34 is increased, but the interference between the balls 36 is eliminated. The rolling characteristics of the are improved. Even if the surface pressure applied to the inner peripheral surface of the roller 32 increases, the crushing strength of the roller 32 is significantly reduced because the roller 32 does not need to be divided into two parts or provided with a groove. There is no. In FIG. 7, for convenience, a single row deep groove ball bearing is shown as the roller assembly 30, but the cage 38 can be disposed even with a double row deep groove ball bearing.

  Generally, the ball bearing cage 38 includes a metal corrugated cage such as stainless steel and a resin crown cage such as a thermosetting resin. As shown in FIG. 9A, the corrugated holder is composed of a pair of corrugated annular members 38a and 38b. The corrugated annular members 38a and 38b are formed into a corrugated shape by pressing an annular metal plate and providing concave portions 38a1 and 38b1 corresponding to the spherical surface of the ball 36 at a plurality of locations in the circumferential direction. The pair of corrugated annular members 38a and 38b are integrated by fixing flat portions 38a2 and 38b2 between the concave portions with rivets 38c, and holding the balls 36 one by one with the concave portions 38a1 and 38b1 facing each other. The ball pocket 39 is formed. The corrugated cage ball pocket 39 is formed in an annular shape so as to surround the entire circumference of the ball 36. As shown in FIG. 9B, in the crown-shaped cage, ball pockets 39 are formed at a plurality of locations in the circumferential direction by resin molding in the same manner as the corrugated cage. The ball pocket 39 of the crown-shaped cage has a substantially C-shaped cross section in which a part of the annular shape is interrupted, and one side in the bearing axial direction is open. The crown-shaped cage is assembled to the ball 36 by elastically expanding one side opening of each ball pocket 39. As a waveform holder and a crown-shaped holder, there is one disclosed in Patent Document 2, for example.

  The ball bearing applicable as the roller assembly 30 of the tripod type constant velocity universal joint is not limited to the single row or double row deep groove ball bearing described above, but is also a single row or double row angular contact ball bearing, self-aligning. There are also ball bearings.

JP 2001-295855 A JP 2003-343567 A Universal Joint and Driveshaft Design Manual Section 3.2.6 “Tripot Universal Joint (End Motion Type)”

  The tripod type constant velocity universal joint is incorporated in a power transmission mechanism such as an automobile or an industrial machine. Since many applications of the tripod type constant velocity universal joint transmit a large torque, there is a problem of increasing the strength of the tripod type constant velocity universal joint.

  The ball bearing used as the roller assembly 30 of the tripod type constant velocity universal joint is housed in the track groove 12 of the outer joint member 10 and is fitted on the leg shaft 22 of the tripod member 20. Restrictions are imposed on dimensions such as width that affect the strength of ball bearings. For this reason, the roller assembly 30 needs to increase its strength within a range of defined dimensions.

  When, for example, a ball bearing having a cage 38 as shown in FIGS. 7 and 8 is used as the roller assembly 30 of the tripod type constant velocity universal joint, the cage 38 is deformed by friction with the ball 36. Is granted. Specifically, when torque is applied to the tripod constant velocity universal joint with the outer joint member 10 and the tripod member 20 being angularly displaced, the roller 32 constituting the roller assembly 30 rolls on the roller guide surface 14. While reciprocating. The ball 36 rotates and revolves within the track as the roller 32 rolls, and contacts the cage 38 on the front side in the revolving direction.

  For example, in FIG. 8, when the roller 32 moves on the roller guide surface 14 on the right side of the drawing to the Y direction positive side, the roller 32 rotates clockwise in the drawing. The ball 36 follows the rotation of the roller 32 and rotates and revolves clockwise in the drawing. The cage 38 comes into contact with the ball 36 on one side in the circumferential direction of the ball pocket 39 by the revolving action of the ball 36, and a deformation force inward in the radial direction is applied to the contact portion by the rotation action of the ball 36. On the other circumferential side of the adjacent ball pocket 39 that is continuous with one circumferential side of the ball pocket 39, a deforming force outward in the radial direction is generated by the above-described deformation force. Following the rotation of the roller 32 in the Y direction from the positive side to the negative side and rotating counterclockwise in the figure, the ball 36 rotates and revolves counterclockwise in the figure, and the ball pocket 39 has one circumferential direction. Away from the side and in contact with the other side. At this time, a deformation force inward in the radial direction is applied to the other circumferential side of the ball pocket 39 by friction with the ball 36, and a radial direction is applied to one circumferential direction of the ball pocket 39 by the above deformation force. An outward deformation force is generated.

  When the retainer 38 is a corrugated retainer, since the corrugated retainer is made of metal, it hardly deforms even when the deformation force is applied by friction with the ball 36. However, internal stress is repeatedly generated in the corrugated cage, and metal fatigue of the corrugated annular member and the rivet is promoted.

  When the cage 38 is a crown-shaped cage, the crown-shaped cage is made of resin. Therefore, when the deformation force is applied, the portion between the ball pockets 39 bends so as to change the tangential direction, By repeating this bending, fatigue of the resin material is promoted.

  Under high-speed rotation, fatigue of the material of the cage 38 is easily promoted, and in some cases, the cage 38 may crack. When such a crack occurs, the holding force of the balls 36 decreases, the distance between the balls 36 becomes uneven, or the balls 36 swing in the axial direction. As a result, the strength of the roller 32 and the ring 34 against the thrust load applied during torque transmission is reduced. Further, wear of the ball 36 is also promoted.

  The present invention has been made in view of such circumstances, and an object thereof is to improve the strength of the cage and extend the life of the tripod type constant velocity universal joint.

  The tripod constant velocity universal joint according to the present invention includes a ball bearing as a roller assembly. The ball bearing has a configuration in which a plurality of balls are disposed between a roller and a ring, and a predetermined interval is provided between the balls by a resin crown-shaped cage. The crown-shaped cage is a ring guide system or a roller guide system. When a radial deformation force acts on the crown-shaped cage due to the rolling of the ball, the crown-shaped cage contacts the outer peripheral surface of the ring or the inner peripheral surface of the roller, and the radius Inward or outward deformation is restricted.

  The cage may be arranged in either a contact state or a non-contact state with respect to the ring or the roller during non-torque transmission. In the contact state, the inner diameter of the cage is substantially the same as the outer diameter of the ring, or the outer diameter of the cage is substantially the same as the inner diameter of the roller. Since the tripod type constant velocity universal joint is usually filled with a lubricant, the cage comes into contact with the ring or the roller via the lubricant. In the non-contact state, a minute gap is provided between the retainer and the ring or between the retainer and the roller so as to contact the ring or the roller due to the deformation of the retainer.

  In the present invention, the resin crown-shaped cage is arranged so as to be guided by the outer peripheral surface of the ring or the inner peripheral surface of the roller, and the deformation of the crown-shaped cage inward or outward in the radial direction is restricted. In addition, the crown-shaped cage is not easily damaged, and as a result, the life of the tripod type constant velocity universal joint can be extended.

  FIG. 1 is a cross-sectional view showing an example of a tripod type constant velocity universal joint according to the present invention, in which a single row deep groove ball bearing is used as a roller assembly. In FIG. 1, the same parts as those in the conventional example are denoted by the same reference numerals. That is, reference numeral 10 is an outer joint member, reference numeral 12 is a track groove, reference numeral 14 is a roller guide surface, reference numeral 20 is a tripod member, reference numeral 22 is a leg shaft, reference numeral 30 is a roller assembly, reference numeral 32 is a roller, reference numeral 33 is a roller. 32 is a track groove, 34 is a ring, 35 is a track groove of the ring 34, 36 is a ball, 38 is a cage, 39 is a ball pocket.

  This tripod type constant velocity universal joint employs a resin-made crown-shaped cage as the cage 38 constituting the roller assembly 30, and this cage 38 is arranged in a ring guide manner. As a constituent material of the cage 38, a high-functional resin such as polyamide 66 (PA66), polyamide 46 (PA46), polyphenylene sulfide (PPS), or a material obtained by adding glass fiber to these high-functional resins is used.

  The cage 38 is a cylindrical member that is narrower than the roller 32 and the ring 34, and has ball pockets 39 at equal intervals in the circumferential direction. The ball pocket 39 is a substantially circular hole formed in the center in the width direction of the cage 38 and is configured by cutting out one side of the circular hole in the cage width direction. The inner diameter of the cage 38 is slightly larger than the outer diameter of the ring 34, and the outer diameter of the cage 38 is sufficiently smaller than the inner diameter of the roller 32. A minute gap is formed between the cage 38 and the ring 34 to such an extent that they can come into contact with each other during torque transmission. On the other hand, a wide gap is formed between the cage 38 and the roller 32 so that they do not contact each other even during torque transmission.

  2 is a cross-sectional view taken along line AA in FIG. The tripod type constant velocity universal joint is used for torque transmission in a state where the outer joint member 10 and the tripod member 20 are angularly displaced. Torque is applied in either the positive or negative direction of the X direction in the figure, and is transmitted between one of the pair of roller guide surfaces 14 and the leg shaft 22 of the tripod member 20 via the roller assembly 30. Is done. Further, during torque transmission, the leg shaft 22 of the tripod member 20 swings along the track groove 12 in the Y direction positive side and the negative side in the drawing. As the leg shaft 22 swings, the roller 32 constituting the roller assembly 30 reciprocates while rolling on one roller guide surface 14. The ball 36 rotates and revolves in the same direction as the rotation direction of the roller 32 as the roller 32 rotates. The ball 36 comes into contact with one side in the circumferential direction of the ball pocket 39 by a revolving action, and imparts a deformation force inward in the radial direction to one side in the circumferential direction of the ball pocket 39 by a turning action. The cage 38 is supported by the outer peripheral surface of the ring 34 even when a radially inward deformation force is applied to one side in the circumferential direction of the ball pocket 39, and the deformation inward in the radial direction is restricted. For this reason, the other circumferential side of the ball pocket 39 is not deformed radially outward, and the cage 38 is not bent due to the rotation and revolution of the ball 36. When the roller 32 changes the moving direction, the ball 36 is separated from one side in the circumferential direction of the ball pocket 39 and comes into contact with the other side, and a deformation force inward in the radial direction is applied to the other circumferential side of the ball pocket 39. Also at this time, the retainer 38 does not bend. Accordingly, the cage 38 is prevented from being deformed with a large amplitude such that a crack is generated, and early breakage is prevented.

  FIG. 3 is a cross-sectional view showing another embodiment of a tripod type constant velocity universal joint according to the present invention. In this tripod type constant velocity universal joint, a resin crown-shaped cage 38 constituting the roller assembly 30 is of a roller guide type. The outer diameter of the cage 38 is slightly smaller than the inner diameter of the roller 32, and a minute gap is formed between the roller 32 and the cage 38. On the other hand, the inner diameter of the retainer 38 is sufficiently larger than the outer diameter of the ring 34, and a wider gap is formed between the ring 34 and the retainer 38 than between the roller 32 and the retainer 38.

  4 is a cross-sectional view taken along line BB in FIG. The ball 36 comes into contact with one side in the circumferential direction of the ball pocket 39 by a revolving action, and imparts a deformation force inward in the radial direction to one side in the circumferential direction of the ball pocket 39 by a turning action. Although the cage 38 is not supported on the radially inner side, the other circumferential side of the adjacent ball pocket 39 connected to one circumferential side of the ball pocket 39 is deformed outward in the radial direction by the inner circumferential surface of the roller 32. Therefore, deformation of the ball pocket 39 toward the radially inner side on one side in the circumferential direction is also restricted. When the roller 32 changes the moving direction, the ball 36 moves away from one circumferential side of the ball pocket 39 and contacts the other side, and deforms the other circumferential side of the ball pocket 39 inward in the radial direction. Since the deformation on one side in the circumferential direction of the opposite ball pocket 39 is restricted by the inner circumferential surface of the roller 32, the deformation inward in the radial direction is restricted on the other circumferential side of the ball pocket 39. As described above, even when the cage 38 is arranged by the roller guide method, deformation with large amplitude that causes a crack is suppressed, and early breakage of the cage 38 is prevented.

  As mentioned above, although one embodiment of the tripod type constant velocity universal joint according to the present invention has been described, the present invention is not limited to the above embodiment, and various modifications are possible. For example, in the tripod type constant velocity universal joint of the above embodiment, the leg shaft 22 of the tripod member 20 is formed into a columnar shape, and the inner peripheral surface of the ring 34 is formed into a cylindrical surface, and the inclination of the roller assembly 30 with respect to the leg shaft 22. However, according to the present invention, as in the prior art, the leg shaft 22 has an elliptical column shape, and the inner peripheral surface of the ring 34 has a partial ring shape. The present invention can also be applied to a tripod type constant velocity universal joint in which the inclination of 30 is positively allowed.

  In the tripod type constant velocity universal joint of the above embodiment, the outer peripheral surface of the roller 32 and the roller guide surface 14 are in circular contact, but the present invention makes the outer peripheral surface of the roller 32 a partial spherical shape, and The present invention can also be applied to a roller guide surface 14 having a substantially V-shaped cross-sectional contour such as a Gothic arch shape or a tapered shape, and the roller 32 and the roller guide surface being in angular contact.

  Furthermore, in the above embodiment, a single row deep groove ball bearing is used as the roller assembly 30, but the present invention is a double row deep groove ball bearing, a single row or double row angular contact ball bearing, a self-aligning ball. The present invention can also be applied to those using other ball bearings such as a bearing.

It is sectional drawing of the direction orthogonal to the axis which shows one Embodiment of the tripod type constant velocity universal joint which concerns on this invention. It is the sectional view on the AA line of FIG. It is sectional drawing of the axis orthogonal direction which shows other embodiment of the tripod type | mold constant velocity universal joint which concerns on this invention. FIG. 4 is a sectional view taken along line BB in FIG. 3. It is sectional drawing which shows an example of the conventional tripod type constant velocity universal joint. It is CC sectional view taken on the line of FIG. It is sectional drawing which shows the other example of the conventional tripod type constant velocity universal joint. It is the DD sectional view taken on the line of FIG. (A) The figure is a principal part expansion perspective view of a waveform holder, and (B) figure is a principal part expansion perspective view of a crown type maintenance machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Outer joint member 12 Track groove 14 Roller guide surface 20 Tripod member 22 Leg shaft 32 Roller 34 Ring 36 Ball 38 Cage

Claims (2)

  An outer joint member that is formed in a bottomed cylindrical shape and has three track grooves extending in the axial direction on the inner periphery and roller guide surfaces on both side walls of each track groove, and three leg shafts in the radial direction. A tripod member that protrudes and is inserted into the outer joint member such that each leg shaft extends into the track groove, a roller that is rotatably inserted into the track groove of the outer joint member, and a tripod member A ring that externally fits on the leg shaft and rotatably supports the roller, a plurality of balls disposed on the track between the roller and the ring, and a resin that holds the plurality of balls at predetermined intervals in the track circumferential direction A tripod type constant velocity universal joint, characterized in that the crown-shaped cage is disposed so as to be guided by the outer peripheral surface of the ring.   An outer joint member that is formed in a bottomed cylindrical shape and has three track grooves extending in the axial direction on the inner periphery and roller guide surfaces on both side walls of each track groove, and three leg shafts in the radial direction. A tripod member that protrudes and is inserted into the outer joint member such that each leg shaft extends into the track groove, a roller that is rotatably inserted into the track groove of the outer joint member, and a tripod member A ring that externally fits on the leg shaft and rotatably supports the roller, a plurality of balls disposed on the track between the roller and the ring, and a resin that holds the plurality of balls at predetermined intervals in the track circumferential direction A tripod type constant velocity universal joint, characterized in that the crown-shaped cage is provided so as to be guided by the inner peripheral surface of the roller.

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