Seal and cross member unit for universal joints

Abstract

A seal for a cross member unit for universal joints has a carrier ring to be inserted into a bearing cup of the cross member unit. The carrier ring has an L-shaped cross section with a cylindrical portion coaxial to a longitudinal axis and a flange portion extending form the cylindrical portion inwardly. An elastomeric sealing lip element is connected to the carrier ring. The sealing lip element has first engagement elements form fittingly engaging into first engagement apertures. The first engagement apertures extend through the flange portion of the carrier ring. The sealing lip element further has second engagement elements form fittingly engaging into second engagement apertures. The second engagement apertures extend through the cylindrical portion of the carrier ring.

Claims

1. A cross member unit for universal joints, comprising: a body portion having at least one trunnion extending outwardly from said body portion, said trunnion includes a sealing surface extending outwardly from said body portion and a bearing surface extending outwardly from said sealing surface, and a bearing cup having an open end, a closed end, and an inner bearing surface, said bearing cup being disposed about said trunnion such that said inner bearing surface of said bearing cup is disposed coaxially about said bearing surface of said trunnion defining a bearing region there between, a bearing with rolling members disposed within said bearing region for permitting rotation of said bearing cup relative to said trunnion, and a seal having a carrier ring and an elastomeric sealing lip element connected to the carrier ring, the carrier ring being mounted in said bearing cup, the sealing lip element sealingly engaging said trunnion sealing surface, said carrier ring having an L-shaped cross section with a cylindrical portion coaxial to a longitudinal axis and a flange portion extending from the cylindrical portion inwardly, said flange portion has a stop face limiting a movement of the rolling members in a direction parallel to the longitudinal axis, wherein said sealing lip element having first engagement elements form fittingly engaging into first engagement apertures, said first engagement apertures extending through said flange portion of the carrier ring wherein the sealing lip element has second engagement elements form fittingly engaging into second engagement apertures, said second engagement apertures extending through said cylindrical portion of the carrier ring.

2. The cross member unit according to claim 1, wherein the carrier ring is made of a plastic material, in particular of a thermoplastic material.

3. The cross member unit according to claim 1, wherein the sealing lip element is made of an elastomer, in particular a synthetic elastomer.

4. The cross member unit according to claim 1, wherein at least one of the first engagement elements and second engagement elements have a connection portion and an engagement portion, said engagement portion projecting from the connection portion in a direction transverse to the extension direction of the respective engagement element.

5. The cross member unit according to claim 4, wherein the connection portions are pin-shaped and the engagement portions have a greater diameter than the respective pin-shaped connection portion.

6. The cross member unit according to claim 5, wherein the first and second engagement apertures are formed intermateable to the first and second engagement elements, respectively.

7. The cross member unit according to claim 6, wherein each of the first engagement elements is arranged with one of the second engagement elements in pairs on one radial plane comprising the longitudinal axis.

8. The cross member unit according to claim 7, wherein at least two of the second engagement apertures extend parallel to each other through the cylindrical portion of the carrier ring.

9. The cross member unit according to claim 8, wherein four groups of three of said second engagement apertures are provided, the second engagement apertures of each group extending parallel to each other through the cylindrical portion of the carrier ring.

10. The cross member unit according to claim 9, wherein one of the second engagement apertures of each group is orientated radially to the longitudinal axis.

11. The cross member unit according to claim 1, wherein the carrier ring comprises a plurality of projections projecting from an outer circumference of the cylindrical portion.

12. The cross member unit according to claim 11, wherein the projections are evenly distributed around the circumference of the carrier ring.

13. The cross member unit according to claim 12, wherein each of the projections is arranged on a common radial plane comprising the longitudinal axis with one of the first engagement apertures and one of the second engagement apertures.

14. The cross member unit according to claim 13, wherein the projections have a slanted face towards the flange portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.

(2) FIG. 1 is a half section of a side elevation view of a driveshaft provided with universal joints;

(3) FIG. 2 is an enlarged cross-section view of a detail of the cross member unit in the area of the seal mounted to the sealing cup along the section line 2-2 according to FIG. 1;

(4) FIG. 3 is a perspective view of the seal; and

(5) FIG. 4 a sectional view of the seal through the engagement elements.

DETAILED DESCRIPTION

(6) FIG. 1 shows a driveshaft with two universal joints 1, 1. Each of the two universal joints 1, 1 include a first joint yoke 2 provided with a flange 3. A second joint yoke 4 is provided per universal joint 1, 1. Both joint yokes 2, 4 are connected to one another by a cross member unit such that the first joint yoke 2 is able to carry out pivot movements around the longitudinal axis 8. The assembly, which includes the first joint yoke 2 and the cross member unit 5, is able to carry out a pivot movement around the second longitudinal axis 7 relative to the second joint yoke 4. The cross member unit 5 includes a cross member 6 with four trunnions 17. Each trunnion 17 includes a bearing assembly which includes a bearing cup 9 received in a yoke bore 10 of the respective joint yokes 2, 4.

(7) A tube 11 is firmly connected to the second joint yoke 4 associated with the joint 1. The tube 11 carries the plunging sleeve 12. The plunging sleeve 12 has a central bore with splines 13. The splines' teeth extend parallel to the longitudinal axis and are worked into the wall of the central bore. A plunging journal 14, with outside splines 15, is longitudinally adjustably received in the sleeve central bore. The plunging journal 14 is firmly connected to the second joint yoke 4 of the universal joint 1. The longitudinal plunging assembly, which includes the plunging journal 14 and the plunging sleeve 12, is able to accommodate changes in length which result from the change in the position of the universal-jointed shaft and from the articulation of the two universal joints 1, 1 relative to one another. The longitudinal plunging assembly is sealed by a protective tube 16. One end of the tube is secured to the second joint yoke 4 of the universal joint 1 and covers the outer face of the plunging sleeve 12. The other end of the protective tube 16 includes a seal which has a sealing function relative to the outer face. The two flanges 3 serve to be connected to a driving and driven part of the driveline into which the universal-jointed shaft is inserted.

(8) FIG. 2 shows a detail of the cross member unit 5 in half section with the sectional plane including the longitudinal axis 7. Part of the cross member 6 with the trunnion 17 is visible. The trunnion 17 extends outwardly from a central body portion 18 of the cross member 6 and has a cylindrical bearing surface 19. The cylindrical bearing surface 19 extends from a shoulder 20 of the trunnion 17. The shoulder cross-section increases starting from the cylindrical bearing surface 19 towards the body portion 18. The shoulder 20 has the shape of a curve. The shoulder 20 is followed by a sealing surface 21. The sealing surface 21 includes a conical face and a cylindrical face with radius transitions. The sealing face 21, via a conical transition, is followed by a preseal sealing surface 22.

(9) The bearing cup 9 with casing 23 includes a cylindrical inner bearing surface 24 and a cylindrical outer surface 26 arranged around the trunnion 17. The cylindrical outer face 26 serves to accommodate the bearing cup 9 in the yoke bore 10 of a joint yoke. Furthermore, the bearing cup 9 includes a base at a closed end 25 of the bearing cup 9.

(10) Rolling members 29, in the form of needles or rollers, are arranged in the annular gap (bearing region 28) between the inner bearing surface 24 of the casing 23 of the bearing cup 9 and the bearing surface 19 of the trunnion 17. A seal 32 is mounted into the open end 27 of the bearing cup 9. The movement of the rolling members 29 parallel to the longitudinal axis 7 towards the body portion 18 is limited by a stop face 31 of the seal 32.

(11) Along the longitudinal axis 7, the seal 32 includes two sealing lips 33, 33 arranged one behind the other. The sealing lips 33, 33 are part of a sealing lip element 30 which is connected to a carrier ring 34. The carrier ring 34 is mounted into the open end 27 with a press-fit while the sealing lips 33, 33 extend towards the sealing surface 21 of trunnion 17. The carrier ring 34 is preferably made of a thermoplastic material while the sealing lip element 30 is made of an elastomeric material.

(12) The carrier ring 34 has an L-shaped cross section including a cylindrical portion 35 coaxially to the longitudinal axis 7 and a flange portion 37 which extends inwardly in the direction towards the longitudinal axis 7. The seal 32, via an outer face 36 of the carrier ring 34, is firmly received in the bearing cup 9.

(13) The sealing lip element 30 is firmly connected to the carrier ring 34. The sealing lip element 30 comprises first engagement elements 47 and second engagement elements 48. The first engagement elements 47 extend along an axis of extension 51 parallel to the longitudinal axis 7 of the trunnion 17. The second engagement elements 48 extend in a direction transverse to the longitudinal axis 7. The axes 49 of extension of the second engagement elements 48 intersect the longitudinal axis 7 or cross the longitudinal axis 7 in a distance.

(14) The first engagement elements 47 are pin-shaped with a circumferential groove 50 around the respective axis of extension 51 of the first engagement elements 47. Hence, in the region of the circumferential groove 50 the first engagement elements 47 have a pin-shaped connection portion 52 terminating into a head-like engagement portion 53 with greater diameter than the connection portion 52.

(15) The first engagement elements 47 are received in first engagement apertures 54 of the carrier ring 34. The engagement apertures 54 are formed intermateable to the first engagement elements 47. Accordingly, the first engagement apertures 54 have the shape of a bore with a circumferential annular collar 55 which is form-fittingly received within the circumferential groove 50 of the respective first engagement element 47.

(16) The second engagement elements 48 are also pin-shaped each with a pin-shaped connection portion 56 terminating into an engagement portion 57 having a greater diameter than the connection portion 56. The second engagement elements 48 are received within second engagement apertures 58 formed intermateable to the second engagement elements 48 being bore-like with a constriction 59 surrounding the connection portion 56 of the second engagement elements 48 and form fittingly engaging behind the engagement portion 57 of the second engagement elements 48.

(17) As can be seen best in FIG. 4, being a cross sectional view perpendicular to the longitudinal axis 7 of the seal and the trunnion 17, the sealing lip element 30 is provided with twelve second engagement elements 48 and second engagement apertures 58. The second engagement elements 48 and second engagement apertures 58 can be constitute four groups. In each of the groups the second engagement elements 48 and second engagement apertures 58 extend parallel to each other. Each group is arranged diametrical to one of the other groups wherein one second engagement element 48 and one second engagement aperture 58 of one group are arranged on the same axis of extension 49 as one second engagement element 48 and one second engagement aperture 58 of the diametrical opposed group.

(18) Each of the groups comprises one second engagement element 48 and one second engagement aperture 58 being radially orientated to the longitudinal axis 7 of the seal, i.e. the axis of extension 49, 49 of the second engagement element 48 intersects the longitudinal axis 7. Two second engagement elements 48 and two second engagement apertures 58 having an axis of extension 49, 49 crossing the longitudinal axis 7 of the seal with a distance.

(19) The outer face 36 of the carrier ring 34 is provided with projections 38 evenly distributed about the circumference of the carrier ring 34 and projecting outwardly away from the longitudinal axis 7. The projections 38 engage into a circumferentially extending groove 39 in the inner face 24 of the bearing cup 9. Alternatively, the projections 38 may be replaced by one circumferential annular projection on the outer circumference of the carrier ring 34.

(20) Each of the projections 38 has a slanted face 41 which faces towards the flange portion. While being inserted into the bearing cup 9 the open end 27 of the bearing cup 9 rides onto the slanted faces 41 of the projections 38 so that the cylindrical portion 35 of the carrier ring 34 is elastically deformed inwardly until the projections 38 reach the groove 39. When reaching the groove 39 the projections 38 snap back outwardly into the groove 39. The projections 38 each have a support face 42 which is orientated substantially radially, i.e. perpendicular to the longitudinal axis 7. The support face 42 is axially supported against a holding face 43 of the groove 39 holding the seal in the bearing cup 9 against moving the seal out of the bearing cup 9.

(21) A preseal 40 is positioned on the front of the open end 27 of the bearing cup 9. The preseal 40 is seated with a connection portion 44 onto an outer connection portion 45 in the bearing cup 9. It will be appreciated that the preseal 40 can be connected to the bearing cup 9 in any know manner. The preseal 40 has a sealing portion 46 which surrounds the trunnion 17 leaving a narrow gap between the sealing portion 46 and the trunnion 17 forming a kind of labyrinth sealing. The sealing portion 46 could also be provided in the form of a sealing lip being in sealing contact to the trunnion 17.

REFERENCE SIGNS

(22) 1, 1 universal joint 2 joint yoke 3 flange 4 joint yoke 5 cross member unit 6 cross member 7 longitudinal axis 8 longitudinal axis 9 bearing cup 10 yoke bore 11 tube 12 plunging sleeve 13 splines 14 plunging journal 15 outside splines 16 protective tube 17 trunnion 18 body portion 19 bearing surface 20 shoulder 21 sealing surface 22 preseal sealing surface 23 casing 24 inner bearing surface 25 closed end 26 cylindrical outer surface 27 open end 28 bearing region 29 rolling member 30 sealing lip element 31 stop face 32 seal 33 sealing lip 34 carrier ring 35 cylindrical portion 36 outer face 37 flange portion 38 projection 39 groove 40 preseal 41 slanted face 42 support face 43 holding face 44 connection portion 45 outer connection portion 46 sealing portion 47 first engagement element 48 second engagement element 49, 49, 49 axis of extension of second engagement element 50 circumferential groove 51 axis of extension of first engagement element 52 connection portion of first engagement element 53 engagement portion of first engagement element 54 first engagement aperture 55 collar 56 connection portion of second engagement element 57 engagement portion of second engagement element 58 second engagement aperture 59 constriction