SLIDING UNIVERSAL JOINT

Abstract: In a sliding universal joint having an outer member (3) with axial grooves (5) and an inner member (4) with radial trunnions (8) each mounting an inner roller (9) a holder (10) and an outer roller (12), cutouts (16) in he holder (10) to allow insertion of the roller (9) are aligned axially by means (6, 13) on the member (3) and the holder (10).

Description: BACKGROUND OF THE INVENTION The present invention relates to a sliding universal joint to be mounted at a bending portion of a bendable driving axle in an automobile, for example, and more particularly to an improvement in a joint including a cylindrical outer member connected to one transmitting shaft and having an inner periphery formed with a plurality of transmitting grooves arranged circumferentially equally spaced from each other and extending axially, an inner member connected to another transmitting shaft and having a plurality of trunnions radially extending to project into the transmitting grooves, an inner roller slidably engaged with an outer periphery of each trunnion, a cylindrical holder having a spherical inner periphery relatively oscillatably engaging with a spherical outer periphery of the inner roller, and an outer roller rotatably supported to an outer periphery of the holder and engaged with each transmitting groove. This type of universal joint is known as disclosed in Japanese Patent Publication No. 57-13211 and in GB-A-2 070 195. In the conventional joint, the spherical inner periphery of the holder is formed with a pair of opposed cutouts. In engaging the spherical outer periphery of the inner roller with the spherical inner periphery of the holder, the inner roller and the holder are arranged so that an axis of the inner roller is perpendicular to that of the holder. Under the condition, the pair of opposed cutouts allow the inner roller to be inserted into the holder. Then, the inner roller is inserted into the cutouts, and is then oscillated at an angle of 90 so that the axis of the inner roller coincides with the axis of the holder. However, as the holder is freely rotatable about its axis, the pair of cutouts are not positioned. Accordingly, when the direction of arrangement of the cutouts becomes coincident with the direction of torque transmission between the outer member and the inner member, effective torque transmitting surfaces of the holder and the inner roller are widely reduced by the cutouts to cause a reduction in durability. SUMMARY OF THE INVENTION The present invention has been achieved to solve the above problem, and it is an object of the present invention to provide a sliding universal joint which may prevent that the effective torque transmitting surface of the holder and the inner roller is reduced. According to the present invention, there is provided in a sliding universal joint wherein the spherical inner periphery of the holder is formed with a pair of opposed cutouts for installing the inner roller into the holder, the improvement comprising a positioning means provided between the holder and the outer member for positioning the holder so as to make the direction of arrangement of the pair of cutouts coincident with the longitudinal direction of the transmitting groove. With this arrangement, the direction of arrangement of the pair of cutouts of the spherical inner periphery of the holder is always restricted to a direction perpendicular to the direction of torque transmission between the outer member and the inner member by the positioning means for positioning the holder. Therefore, an effective torque transmitting surfaces of the holder and the inner roller are hardly reduced by the cutouts. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a vertical sectional view of the preferred embodiment of the sliding universal joint according to the present invention; Fig. 2 is an enlarged view of the essential part in Fig. 1; Fig. 3 is a cross section taken along the line III-III in Fig. 3; Fig. 4 is an enlarged cross section taken along the line IV-IV in Fig. 3; and Fig. 5 is an end view of the holder as viewed from the restrict flange side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT There will now be described a preferred embodiment of the present invention with reference to the drawings. Referring first to Figs. 1 to 3, two transmitting shafts 1 and 2 are connected to each other through a sliding universal joint J of the present invention. The joint J primarily comprises a cylindrical outer member 3 integrally formed with an end portion of the transmitting shaft 1 which the outer member 3 is open at one end thereof, and an inner member 4 fixed to an end portion of the transmitting shaft 2 and received in the outer member 3. The outer member 3 is formed on its inner peripheral surface with three axially extending transmitting grooves 5 circumferentially equally spaced from each other, and each groove 5 is provided with a pair of rail portions 6 inwardly projecting from opposite inner side edges of the groove 5 toward an opening of the groove 5. The inner member 4 fixed to the transmitting shaft 2 is formed with a boss 7, and the boss 7 is integrally formed on its outer peripheral surface with three trunnions 8 projecting into the three transmitting grooves 5. An inner roller 9 having a spherical outer periphery is slidably engaged with an outer periphery of each trunnion 8 in such a manner that a center of the inner roller 9 lies on an axis of the trunnion 8. a cylindrical holder 10 having a spherical inner periphery is relatively oscillatably engaged with the spherical outer periphery of the inner roller 9. A cylindrical outer roller 12 is rotatably supported through a needle bearing 11 to the outer periphery of the holder 10, and is rollingly engaged with the inner surface of the transmitting groove 5. As shown in Figs. 3 to 5, the spherical inner periphery of the holder 10 is formed with a pair of opposed cutouts 16 for installing the inner roller 9. The pair of opposed cutouts 16 are so formed as to extend from one end of the holder 10 to a deepest position of the spherical inner periphery of the holder 10. The cutouts 16 have a width b slightly greater than an axial width a of the inner roller 9. Accordingly, when installing the inner roller 9 in the holder 10, the inner roller 9 is first arranged relative to the holder 10 in such a manner that an axis of the inner roller 9 is perpendicular to an axis of the holder 10, and the inner roller 9 is inserted into the cutouts 16 (See Fig. 5). Then, the inner roller 9 is oscillated at an angle of 90° so that the axis of the inner roller 9 coincides with the axis of the holder 10, thereby engaging the spherical outer periphery of the inner roller 9 with the spherical inner periphery of the holder 10. The holder 10 is integrally formed at its inner end with a restriction flange 13 slidably abutting against the rail portions 6. A presser plate 14 is mounted at an outer end portion of the holder 10 by a circlip 15. The presser plate 14 cooperates with the restriction flange 13 to restrict an axial movement of the outer roller 12. An outer end of the holder 10 slidably abuts against a bottom surface of the transmitting groove. 5. As shown in Fig. 4, the restriction flange 13 is formed in a rectangular shape so as to restrict a direction of arrangement of the cutouts 16 to a direction perpendicular to a torque transmitting direction T, that is, to a longitudinal direction of the transmitting groove 5. Further, the restriction flange 13 is slidably engaged with the transmitting groove 5. Further, the restriction flange 13 has a side length A along a transverse direction of the transmitting groove 5 slightly smaller than an outer diameter D of the outer roller 12, and has the other side length B along the longitudinal direction of the transmitting groove 5 greater than a width C of the transmitting groove 5. Accordingly, as far as the direction of arrangement of the cutouts 16 is not made coincident with the longitudinal direction of the transmitting groove 5, the restriction flange 13 cannot be inserted into the transmitting groove 5. Thus, it is possible to prevent erroneous installation of the restriction flange 13 such that the direction of arrangement of the cutouts 16 is made coincident with the transverse direction of the transmitting groove 5. Referring back to Fig. 1, a flexible boot 18 is provided between the outer member 3 and the transmitting shaft 2 to cover the front opening of the outer member 3. A rear end of the flexible boot 18 is engaged with an outer circumferential groove 19 of the outer member 3, and is tightened by a band 20, while a front end of the flexible boot 18 is engaged with an outer circumferential groove 21 of the transmitting shaft 2, and is tightened by a band 22. In operation, when a torque is applied to the transmitting shaft 1, for example, the torque is transmitted form the outer member 3 to the inner member 4, that is, from one side surface of the transmitting groove 5 through the outer roller 12, the holder 10 and the inner roller 9 to the trunnion 8 and the boss 7, and is finally transmitted to the transmitting shaft 2. During such transmission of the torque, the rectangular restriction flange 13 is restrained from rotation by the transmitting groove 5, and always restricts the direction of arrangement of the pair of cutouts 16 to the longitudinal direction perpendicular to the torque transmitting direction T. Accordingly, there is almost no possibility that an effective torque transmitting surface of the holder 10 and the inner roller 9 is reduced by the cutouts 16, but a large torque transmission can be effected between the holder 10 and the inner roller 9. Further, the restriction flange 13 abuts against the rail portion 16 to thereby restrict inclination of the holder 10. Therefore, even when the trunnion 8 is inclined in the transmitting groove 5 by a bending operation of the transmitting shafts 1 and 2, the outer roller 12 supported to the holder 10 is not inclined, but it can be smoothly rolled on the opposite side surfaces of the transmitting groove 5. On the other hand, when the trunnion 8 is inclined, the inner roller 9 is oscillated relative to the holder 10 as slightly sliding on the trunnion 8, so that an inclination moment to be applied to the holder 10 may be made small. Further, also in the case that both the transmitting shafts 1 and 2 are axially displaced, the outer roller 12 is not inclined, but it can be smoothly rolled on the opposite side surfaces of the transmitting groove 5. In the above preferred embodiment, the transmitting groove 5 and the restriction flange 13 constitute the positioning means of the present invention. As described above, there is provided between the holder and the outer member the positioning means for positioning the holder so as to make the direction of arrangement of the pair of cutouts coincident with the longitudinal direction of the transmitting groove. Therefore, the direction of arrangement of the cutouts. Accordingly, a large torque transmission between the holder and the inner roller may be achieved, and the durability of the holder and the inner roller may be improved.

Claims: A sliding universal joint (J) including a cylindrical outer member (3) connected to one transmitting shaft (1) and having an inner periphery formed with a plurality of transmitting grooves (5) arranged circumferentially equally spaced from each other and extending axially, an inner member (7, 8) connected to another transmitting shaft (2) and having a plurality of trunnions (8) radially extending to project into said transmitting grooves (5), an inner roller (9) slidably engaged with an outer periphery of each trunnion (8), a cylindrical holder (10) having a spherical inner periphery relatively oscillatably engaging with a spherical outer periphery of said inner roller (9), and an outer roller (12) rotatably supported to an outer periphery of said holder (10) and engaged with each transmitting groove (5), wherein said spherical inner periphery of said holder (10) is formed with a pair of opposed cutouts (16) for installing said inner roller (9) into said holder (10), characterized in that a positioning means (13) is provided between said holder (10) and said outer member (3) for positioning said holder (10) so as to make the direction of arrangement of said pair of cutouts (16) coincident with the longitudinal direction of said transmitting groove (5). The sliding universal joint as set forth in claim 1 characterized in that said positioning means (13) is a restriction flange (13) at the holder (10) slidably abutting against rail portions (6) projecting inwardly from opposite inner side edges of each transmitting groove (5) toward an opening of the groove (5) and slidably engaged with the transmitting groove (5). The sliding universal joint as set forth in claim 1 or 2, characterized in that an outer end of the holder (10) slidably abuts against a bottom surface of the transmitting groove (5). The sliding universal joint as set forth in any of claims 2 to 3, characterized in that the restriction flange (13) is formed in a rectangular shape. The sliding universal joint as set forth in claim 4 characterized in that the restriction flange (13) has a side length (A) along the transverse direction of the transmitting groove (5) slightly smaller than the outer diameter (D) of the outer roller (12). The sliding universal joint as set forth in claim 4 or claim 5 characterized in that the restriction flange (13) has a side length (B) along the longitudinal direction of the transmitting groove (5) greater than the width (C) of the transmitting groove (5).

Inventors: ESAKI, SEIJI, HASHIMOTO, YASUSHI, KURITA, SHIGEO, SASAKI, AKIRA
Applicants: HONDA GIKEN KOGYO KABUSHIKI KAISHA
Application year: 1988
Main classification: F16D3
IPC codes: F16D3