FR2747748A1 - TRANSMISSION JOINT AND MALE ELEMENT FOR SUCH A JOINT - Google Patents

Abstract

The body (4) of the male element (2) of the joint is fixed to the associated transmission shaft (3) in an area (39) where, in an aligned position of the joint, it is axially displaced towards the end of the shaft with respect to the median plane (P) of the swivelling connecting means (5, 6) of the male and female elements (8). The body (4) defines a free internal space (104) open on the opposite side and in which the closing member (13) of the joint cavity is linked to the said shaft (3) or to the body (4) of the male element. This invention is useful for quadripod type universal joints.

Description

 The present invention relates to a transmission joint of the type comprising a male element which comprises a body integral with a first shaft, a female element intended to be made integral with a second shaft, swiveling means for securing in rotation said body with the female element, and a sealing member which is fixed to the female element and which hermetically closes the seal cavity on the side of said first shaft.

 The invention applies in particular to axially fixed or quasi-fixed quadripod seals for motor vehicle transmissions.

 Transmission joints of the above type, in particular the X-pode joints or the ball joints, conventionally comprise as shutter member a bellows of generally convergent shape fixed by its large end to the female element and fixed by its small end to the shaft secured to the male element. However, when a transmission joint works continuously, or almost continuously, at a high angle, and in particular when its speed of rotation is high, the design of a bellows which is reliable and durable poses serious difficulties.

 The invention aims to solve this problem and, for this purpose, it relates to a transmission joint of the aforementioned type, characterized in that the body of the male element is fixed to said first shaft in an area thereof. ci which, in the aligned position of the joint, is axially offset, towards the end of this shaft, with respect to the median plane, perpendicular to the same shaft, of said swiveling securing means, this body defining a free interior space open on the opposite side and wherein the shutter member is connected to said first shaft or to said body.

The transmission joint according to the invention may include one or more of the following characteristics
- The shutter member carries a sealing member which rubs on an associated surface, in particular spherical, of said first shaft;
- The closure member ends with a drop-down bellows, the end of which is hermetically fixed to a surface of revolution of the body of the male element;
the unrolling bellows is turned back radially outwards, its end being fixed to an interior surface of revolution of the body of the male element;
- Said first shaft carries a protuberance of revolution, serving to support the radially inner part of the bellows;
- said inner surface of revolution and said protuberance of revolution are spherical, concentric and centered at a point on the axis of said first shaft which is offset, in the direction opposite to the end of this tree, relative to said median plane;
- The body of the male element has spherical surfaces which cooperate with axial retaining surfaces of the female element or of a retaining member connected to the latter;
- The retaining member comprises two vis-à-vis half-shells fixed in the female element;
- One of the half-shells has a convergent appendage, the end of which carries said sealing member;
- Said swiveling means comprise several rotating and sliding rollers mounted on arms which extend from the body of the male element, in particular four rollers trapped in oscillating corridors of the female element, the edges of the corridors being coupled together to others to synchronize their oscillations;
- Said male element consists of a nut provided with external grooves, the seal being of the constant velocity joint type with balls.

 The invention also relates to a male element intended for a transmission joint as defined above. This male element, of the type comprising a body intended to be fixed by a zone for fixing to a shaft and to be connected by ball-and-socket jointing means in rotation with a female element of the seal, is characterized in that the fixing zone is axially offset, in a first direction, relative to the median transverse plane of the swiveling means, and in that the body defines a free interior space open in the opposite direction.

 In one embodiment of this male element, the body has the general shape of a dome, the apex of which has an opening which defines said fixing zone, said swiveling means being adjacent to the large base of the dome.

 Said swiveling means may comprise several arms, in particular four arms, projecting from the body.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which
- Figure 1 is an axial sectional view, along the broken line II of Figure 2, of a transmission seal of the quadripod type according to the invention, in the aligned position;
- Figure 2 is a half-view taken in section along line II-II of Figure 1;
- Figure 3 shows in axial section the male element of the joint of Figures 1 and 2;
- Figures 4 and 5 are perspective views, on one side and the other, of the same male element;
- Figures 6 to 8 are views, respectively in axial section, in internal perspective and in external perspective, of a half-shell of the joint;
- Figures 9 to 11 are views, respectively in perspective, from the side and from the front, of the other half-shell of the seal;
- Figure 12 is a view similar to the
Figure 1 of a variant, taken in section along the broken line XII-XII of Figure 13;
- Figures 13 and 14 are views similar to Figure 12 but showing the seal in two opposite positions of maximum angularity;
- Figure 15 is a view similar to the
Figure 1 of another variant;
- Figure 16 is a view similar to the
Figure 15, showing the joint of this Figure 15 in a position of maximum angularity;
- Figure 17 is a half-view in axial section of a variant of Figure 15;
- Figure 18 shows in axial section an application of another variant of the transmission joint according to the invention;
- Figure 19 shows in axial section another embodiment of the transmission joint according to the invention, of the ball type; and
- Figure 20 is a similar view showing the seal of Figure 19 in a position of maximum angularity.

 The constant velocity joint 1 shown in Figures 1 and 2 is a fixed joint of the quadripod type. Its general structure is that described, in several embodiments, in FR-A-2,566,858 and 2,678,331.

So joint 1 basically includes
a male quadripod cross member 2, fixed on a first shaft 3 and itself comprising a one-piece body 4 of revolution on which protrude four radial arms 5 made of material, and a roller 6 externally spherical and internally cylindrical, mounted to rotate and sliding on each arm by means of a crown of needles 7;
- A female element 8, intended to be connected to a second shaft (not shown) and itself comprising a cylindrical outer barrel 9, provided with a flange 10 for its connection to said second shaft, and four oscillating channels 11 coupled together ;
- A first half-shell 12, for axial positioning of the quadripod spider, constituting the bottom of the joint cavity; and
a second half-shell 13 for axial positioning of the quadripod spider, which also forms a member for closing the seal cavity on the side of the shaft 3.

 The axis X-X of the male element 2 and the axis Y-Y of the female element 8 are combined in FIGS. 1 and 2.

As can be seen in Figures 3 to 5, the body 4 of the spider has the general shape of a dome of revolution whose top is pierced with a grooved bore 14 of axis XX. The outer surface of the body 4 is spherical, and its center coincides with the center
O of the joint. The inner surface 16 of the body 4 is frustoconical and defines an internal cavity 104 of the body 4. The four arms 5 project radially from this body in the vicinity of the large base of the dome, 90 "from each other. Each arm has a diving 17 with cylindrical bottom intended to receive the needles 7. The transverse plane P which contains the axes of the four arms passes through the point O, and the bore 14 is entirely located clearly outside this plane P.

 The barrel 9 of the female element 8 has a section with four lobes visible in FIG. 2. It has internally, in each lobe, a recess 18 provided in its middle with an axial groove 19. Each passage 11, with cross-section U open towards the axis XX, internally has two cylindrical tracks 20 facing one another, for the associated roller 5, and externally an axial rib 22 made of material projecting in the middle of its outer surface 21 and which is received in the groove 19, to carry out the driving of the barrel 9, therefore of the female element 8, in the circumferential direction.

 In addition, on each side, the axial edge of each lane is coupled to the adjacent edge of the neighboring lane by a single tooth engagement 23.

 The half-shell 12 (FIGS. 1 and 6 to 8) has the general shape of a flat flange, the outside outline of which, square with rounded corners and shallow recesses in the middle of each side, matches the inside outline of the barrel 9. This flange has on the same side a spherical central recess 24 of relatively large radius, centered at the center O of the joint, and, around this recess 24, four recesses 25 of generally spherical shape, of smaller radius. The five recesses 24 and 25 open towards the shaft 3. At the periphery of the recess 24 and between the recesses 25, four tongues 26 extending axially, internally spherical with center O or with a very open V section, protrude towards the tree 3.

 The flat outer region 27 of the half-shell 12 is received in a recess 28 of the flange 10 (Figure 1) and remains held against the bottom of this recess by an elastic ring 29. The region 27 then maintains the corridors 11 against a shoulder 30 cask 9.

 We find in the half-shell 13 (Figures 1 and 9 to 11) a flat outer region 31, whose contour is similar to that of the half-shell 12, and four recesses 32 of generally spherical shape, open towards the recesses 25 and located respectively opposite them (Figure 1).

 There are also, between the recesses 32, four tabs 33 similar to the tabs 26 and located opposite these. However, the half-shell 13 comprises in its central region a converging frustoconical appendage 34, directed towards the half-shell 12, which, at its end, has an inner circular groove 35 for the reception of a sealing ring 36 (Figure 1 ). The periphery of the region 31 is positioned against a shoulder 37 of the barrel 9 adjacent to the shoulder 30. The ring 36 rubs on a spherical projection 38 of the shaft 3 centered at the center O of the joint.

 The shaft 3 also has at its end a grooved region 39 on which is fitted the grooved bore 14 of the body 4, the axial retention of the latter being ensured by a circlip 40. The region 39 is entirely offset, towards the end of the shaft, relative to point 0. The median plane P of the spider passes through this point O, and the appendage 34 penetrates into the cavity 104 of the body 4 to allow the rod 36 to be applied on the projection 38 of the tree 3. The point 0 is also the center of the rod 36.

 As can be seen in FIG. 1, the tongues 26 and 33 are in abutment in pairs, which defines four spherical recesses 41 of center O in which four zones of the external surface 15 of the body 4 pivot between the arms 5. In addition, the edges of the four oscillating corridors 11 struggle in the free spaces 42 located between the tongues 26 and 33 on the one hand, and the inner surface of the barrel 9 on the other hand.

 In the variant of FIGS. 12 to 14, the barrel 9 has a curved bottom 24A made in one piece, bordered on the side of the joint cavity by four recesses 25A. The half-shell 12 no longer forms but a flange provided with the four tongues 26 and, on the other side, reliefs 43 for positioning in the bottom 24A.

 In addition, the half-shell 13 is substantially symmetrical with the half-shell 12 with respect to the plane P, and the frustoconical appendage 34A forms part of an additional part 44 of revolution fixed by a collar 45 on the periphery of the barrel 9 and now the two half-shells pressing against a shoulder 46 thereof adjacent to the bottom 24A. The part 44 defines a hollow annular region which forms a recess 32A opposite each recess 25A, circumferentially between the tongues 33.

 When the seal is in line (Figure 1 or 12), the shaft 3 is positioned axially by the aforementioned cooperation 15-41, and its end is close to the recess 24 or 24A, which is centered at point O.

 At an angle (Figures 13 and 14), the four aforementioned areas of the surface 15 swivel in the recesses 41, the rollers penetrate into the recesses 25 or 25A on one side, 32 or 32A on the other side, and the ring d sealing 36 ball joint on the projection 38 of the shaft 3. As described in the aforementioned FR-A, the lanes 11 oscillate in phase opposition two by two, thanks to their lateral couplings and to the association of the ribs 22 with the grooves 19.

 The cooperation of the rod 36 and the projection 38 takes place very close to the center O of the joint. Relative movements are therefore minimal, and the wear of the seal is low. This wear is all the lower as the centrifugation effect reduces the friction between the rod 36 and the projection 38.

 Furthermore, the lubricating oil present in the seal cavity is centrifuged outward, so that the rod 36 does not operate under oil pressure.

 For all these reasons, a reliable and durable seal is obtained, even if the joint operates permanently or almost permanently at an angle and if the angular speed is high.

 In all the variants described so far, the appendix 34, 34A which carries the sealing ring 36 is theoretically not subject to any deformation and, consequently, could consist of a piece of rigid sheet metal. However, due to manufacturing tolerances, it is preferable to produce the part which carries this appendage in a flexible material, for example a plastic material.

 Of course, in the case of an X-pode joint subjected, during the rotation at an angle, to an offset movement, for example in the case of a tripod joint, the flexibility of appendix 34, 34A would be imperative.

 The variant in FIGS. 15 and 16 differs from the previous one only in that the appendix 34A is replaced by an attached drop-down bellows 47. The large base of the latter is fixed on the periphery of a central orifice of the part 44 , and the bellows penetrates converging to the bottom of the cavity 104 of the body 4, then turns back towards the outside. Its end comprises an outer bead 48 which snaps into a groove formed in the inner surface 16 of the body 4, which is spherical.

 The projection 38 of the shaft 3 is replaced by a spherical projection 49, of larger radius, which supports the intermediate part of the bellows. For reasons of space, the center Ol of this projection, which is also the center of the surface 16, is offset with respect to the point O, towards the half-shell 13.

 It should be noted that in this variant, the body 4 must be of revolution. On the contrary, in the case of Figures 1 and 2 or 12 to 14, the body 4 could comprise only four inclined arms each carrying an arm 5.

The variant of Figure 17 differs from that of Figures 15 and 16 by the following points
- The protuberance 49 is removed, so that the shaft 3 is smooth. However, the convex shape 147 of the internal region of the bellows 47 is retained, during the molding of this part, which essentially eliminates the friction between the bellows and the shaft;
- An elastic ring 148 firmly applies the bead 48 in the groove of the body 4; and
the part 44 has a radially outer extension 144 received behind an inner rim 109 of the barrel 9, and the passages 11 are held axially between this rim and, as in FIG. 1, a flat outer zone 27 of the half-shell 12, which constitutes the bottom of the joint cavity.

 Figure 18 illustrates the use of two seals 1 according to the invention which are not axially fixed like those described above, but quasi-axial fixity. This means that the shaft 3, which carries the bodies 4 at its two ends, has a limited freedom of axial movement in each joint 1. For this, in each joint, the four recesses 41 defined by the two half-shells have two spherical ends 41A connected by a cylindrical section 41B.

 In this example, each seal 1 is hybrid between the variants of FIGS. 1 and 15: the cavity of the seal is delimited on both sides by the half-shells, and the sealing member is a rolling bellows 47. The two seals are mounted symmetrically with respect to the middle of the shaft 3.

 This arrangement with two axially quasi-fixed joints is particularly suitable for connecting a differential outlet of a motor vehicle to the hub of a rear drive wheel, which only undergoes vertical deflections.

 Figures 19 and 20 show that the invention can also be applied to a ball joint 1A, comprising an inner spherical spherical outside 51 fixed on the shaft 3, an outer barrel 52 internally spherical with connection flange 53, six balls 54 partially received in axial external grooves 55 of the nut and partially in internal axial grooves 56 of the barrel, and a spherical cage 57 for holding the balls in the bisector plane of the joint.

 The seal cavity is closed on one side by a domed cover 58 made of sheet metal, placed opposite the end of the shaft 3, and on the other side by a shutter member 59. The nut 51 has a general dome shape analogous to that of the body 4 described above, so as to define an interior cavity 151 open towards the shaft 3. At its top, the dome has, as previously, a grooved axial bore, entirely offset from the plane P , which is mounted on the grooved end region 39 of the shaft 3.

 The member 59 is fixed by its large base on the periphery of the barrel and comprises, as in FIGS. 1 and 12, a frustoconical appendage 34B which penetrates into the cavity 151 of the nut and carries at its end the sealing rod 36, which rubs on the spherical projection 38, centered at the center O of the seal, of the shaft 3.

 The operation and the advantages of the seal of FIGS. 19 and 20 are similar to what has been described above, except as regards the means for securing in rotation the two main elements 51 and 52 of the seal, and the axial fixity is obtained. conventionally by cooperation of the cage 57 with spherical regions 60 of the barrel cavity, located between the grooves 56.

Claims (14)

 1 - Transmission joint, of the type comprising a male element (2; 51) which comprises a body (4; 51) integral with a first shaft (3), a female element (8; 52) intended to be made integral d '' a second shaft, swiveling means (6, 54) for securing in rotation said body with the female element, and a shutter member (13; 44; 44, 47; 59) which is fixed to the female element and which hermetically closes the seal cavity on the side of said first shaft (3), characterized in that the body (4; 51) of the male element (2) is fixed to said first shaft (3) in a zone (39) of the latter which, in the aligned position of the joint, is axially offset, towards the end of this shaft, relative to the median plane (P), perpendicular to the same shaft (3), of said swiveling fastening means (6; 54 ), this body (4; 51) defining a free interior space open on the opposite side (104; 151) and in which the shutter member (13; 44; 44, 47; 59) is connected to said p remier tree (3) or to said body (4; 51).  2 - transmission joint according to claim 1, characterized in that the closure member (13; 44; 59) comprises a sealing member (36) which rubs on an associated surface (38), in particular spherical, of said first tree (3).  3 - transmission joint according to claim 1, characterized in that the closure member comprises a drop-down bellows (47) whose end (48) is hermetically fixed to a surface of revolution (16) of the body (4) of the male element (2).  4 - Transmission joint according to claim 3, characterized in that the unrolling bellows (47) is turned back radially outwards, its end (48) being fixed to an inner surface of revolution (16) of the body (4) of the male element.  5 - Transmission joint according to claim 4, characterized in that said first shaft (3) carries a protuberance of revolution (49), serving to support the radially inner part of the bellows  (47).  6 - Transmission joint according to claim 5, characterized in that said inner surface of revolution (16) and said protuberance of revolution (49) are spherical, concentric and centered at a point (01) of the axis (XX) of said first shaft (3) which is offset, in the direction opposite to the end of this shaft (2), relative to said median plane (P).  7 - Transmission joint according to any one of claims 1 to 6, characterized in that the body (4; 51) of the male element (2; 51) has spherical surfaces (15) which cooperate with surfaces of axial retention (41; 60) of the female element  (8; 52) or a retaining member (12, 13) connected to the latter.  8 - Transmission joint according to claim 7, characterized in that the retaining member (12, 13) comprises two half-shells facing each other fixed in the female element (8).  9 - Transmission joint according to claims 2 and 8 taken together, characterized in that one (13) of the half-shells (12, 13) has a convergent appendage (34) whose end carries said sealing member (36).  10 - Transmission joint according to any one of claims 1 to 9, characterized in that said swiveling means (6) comprise several rotary and sliding rollers mounted on arms (5) which extend from the body (4) of the male element (2), in particular four rollers trapped in oscillating corridors (11) of the female element (8), the edges (23) of the corridors being coupled to each other to synchronize their oscillations.  11 - Transmission joint according to any one of claims 1 to 9, characterized in that said male element (51) consists of a nut provided with external grooves (55), the seal (1A) being of the constant velocity joint type with marbles.  12 - Male element (2; 51) of transmission joint, of the type comprising a body (4; 51) intended to be fixed by a fixing zone (14) to a shaft (3) and to be connected by swiveling means (6; 54) for securing in rotation with a female element (8; 52) of the joint, characterized in that the fixing zone (14) is offset axially, in a first direction, relative to the median transverse plane (P) swiveling means, and in that the body (4; 51) defines a free interior space (104; 151) open in the opposite direction.  13 - Element according to claim 12, characterized in that the body (4; 51) has the general shape of a dome, the apex of which has an opening (14) which defines said fixing zone, said swiveling means (6; 54 ) being adjacent to the large base of the dome.  14 - Element according to claim 12 or 13, characterized in that said swiveling means (6) comprise several arms (5), in particular four arms, projecting from the body (4).