Stop ring for the balls of a constant velocity joint with a sealing bellows

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The field of the invention is that of transmission joints, in particular transmission joints.

[0002] More specifically, the invention relates to a ball retaining ring of a transmission joint adapted to be mounted on one end of a protective bellows of the transmission joint.

[0003] The invention finds applications in particular in the automotive field, in particular in the transmission of the drive wheels of a motor vehicle, and more generally in the context of the transmission of movement and force between shafts forming an angle between them. STATE OF THE ART

[0004] Techniques for retaining ball joints in ball transmissions are known from the prior art, particularly for Rzeppa type transmission joints.

[0005] Ball joints are generally used for the transmission of rotation between two shafts forming an angle, which is often variable.

[0006] Ball joint transmissions generally consist of a part called a bowl, in which is arranged a part called a nut, the nut having grooves accommodating the balls of the transmission joint.

[0007] In other words, the balls are simply inserted into the grooves of the nut. When the shafts form a significant angle of one degree, the balls are brought into extreme positions in the grooves, which can result in the ball coming out of the transmission joint.

[0008] This results in numerous disadvantages, such as a loss of transmissible torque, greater wear of the transmission joint, as well as unbalance on the protective bellows generally mounted on the transmission joint.

[0009] A technique is known from the prior art, for example from document WO 2009 075 603 A1, making it possible to overcome these drawbacks, namely the arrangement of a bowl, for example made of sheet steel, on the bowl, the bowl forming a stop for the balls likely to come out of their groove.

[0010] However, this solution can result in an additional step during the assembly of the transmission joint, involving a significant loss of time and additional financial cost. These consequences are particularly damaging in the automotive sector, subject to significant constraints in terms of production rate and costs.

[0011] Document WO 2008 108 306 A1 describes another solution consisting of reinforcing part of the bellows by overmolding, which adds a step to the manufacture of the bellows.

[0012] Thus, none of the current systems can simultaneously meet all the required needs, namely to propose a technique for preventing one or more balls from coming out of the groove of the transmission joint, which is simple and inexpensive to implement, while not requiring any additional step during the assembly of the transmission joint. STATEMENT OF THE INVENTION

[0013] The present invention aims to remedy all or part of the drawbacks of the state of the art cited above.

[0014] To this end, the invention relates to a ball retention ring for a transmission joint, adapted to be mounted on one end of a protective bellows of the transmission joint, said retention ring comprising: a deformable annular portion, of constant diameter, adapted to receive a clamping collar of said bellows on said transmission joint, and a retention collar extending towards the inside of the retention ring, so as to form a retention stop for the balls of the transmission joint, preventing the axial exit of said balls from the transmission joint.

[0015] These arrangements allow the clamping of a protective bellows onto a transmission joint while preventing any ball from coming out of the transmission joint, without requiring additional steps when mounting the bellows onto the transmission joint. Thus, the mounting of the retaining ring and the protective bellows is carried out in a single operation.

[0016] In fact, the deformable annular portion is designed so as to allow its tightening at the same time as the tightening of the protective bellows on which the retention ring is arranged, by means of a clamp.

[0017] It should be noted that it is not possible to achieve the stop function solely by adapting the shape of the protective bellows, the latter being too flexible and incapable of retaining the balls likely to come out of the transmission joint on its own. The presence of the retention collar is therefore essential for the proper retention of the balls, while allowing the bellows design to be kept simple.

[0018] It is also specified that generally, the retention ring is delivered pre-positioned on a protective bellows, the operator in charge of assembly only having to fix the two pre-assembled elements on top of each other simultaneously, thus not adding any additional fixing step for the end user of the product.

[0019] In summary, the retention ring allows a dual function of holding the bellows on the seal, and retaining balls in the seal, while requiring no additional parts or elements compared to a conventional retaining ring. In other words, the ring according to the invention alone allows ball retention. In addition, it is possible to use a conventional seal with the retention ring, the retention function being provided entirely by the retention ring.

[0020] According to an advantageous variant, the retention collar has an internal surface portion at which the diameter of the collar decreases the further one moves axially from a bowl of the transmission joint, when the ring is mounted on said bellows.

[0021] In other words, the retention collar has an internal surface portion of substantially truncated cone shape, the substantially truncated cone shape being open towards said balls of the transmission joint when the ring is mounted on said bellows. By “substantially truncated cone” shape is meant a shape inscribed between two concentric truncated cones, with diameters of the same order of magnitude.

[0022] In this way, the balls face a generally frustoconical surface which prevents them from escaping axially, the diameter at the level of the frustoconical surface decreasing the further one moves axially from the bowl of the transmission joint, that is to say from the nominal location of the balls.

[0023] In particular, such a shape allows for greater bending between the shafts connected by the transmission joint, compared to a perfectly vertical stop. Indeed, in an extreme position, a ball may be partially outside the bowl, without losing contact with either the bowl or the nut of the transmission joint. In such a case, it is not necessary for the ball to immediately butt against the retention stop, but to butt progressively as it leaves the bowl. Such a progressive stop is thus made possible by the generally truncated cone-shaped shape. However, it is specified that the retention shape can be adapted and take shapes other than generally truncated cone-shaped, in order to retain the ball under all operating conditions of the transmission.

[0024] According to a particular variant, the retention collar is linked to the annular portion by a side of greater diameter, so as to form a retention ring of constant diameter, then decreasing, in the direction going from the annular portion towards the retention collar.

[0025] Thus, the retention ring comprises two clearly defined zones, a zone of constant diameter used for positioning and fixing the ring on the bellows and the bowl of the transmission joint, and a zone providing a retention stop. In particular, the connection between the collar and the annular portion is a material connection, although it is possible to connect the two parts by gluing, clipping, screwing, etc.

[0026] According to an advantageous embodiment, the deformable annular portion consists of a tubular wall comprising at least one through slot made in an axial direction of the ring, so as to reduce the rigidity of said annular portion. According to another variant, the slot is not through, but forms a groove substantially reducing the rigidity of the annular portion.

[0027] In this way, it is possible to arrange and tighten a clamp on the annular portion, the flexibility of the annular portion due to the slot(s) made allowing the clamp to enclose both the annular portion, the bellows and the bowl of the transmission joint. It is understood that such tightening would be impossible if the annular portion remained rigid.

[0028] Any other solution to reduce the rigidity of the annular portion is also possible, such as the presence of other slots, arranged differently, or the use of a more flexible material, capable of elastic deformation. In the latter case, it is possible to make the retention ring in two parts of different material, the parts being subsequently linked by a suitable means.

[0029] According to a particular variant, the tubular wall comprises four through slots distributed regularly on said tubular wall.

[0030] In this way, a satisfactory compromise between flexibility and strength of the annular portion is obtained. Of course, it is possible to make two, three, five, six, or any other greater number of slots.

[0031] According to a preferred embodiment, the deformable annular portion comprises, on its outer surface, means for positioning, or axial pre-positioning of the clamping collar on said retaining ring.

[0032] Thanks to these provisions, the axial positioning of the clamping collar is carried out effortlessly by the operator responsible for assembly, and furthermore, axial displacement of the clamped collar can be avoided, thereby preventing the protective bellows from becoming detached and the transmission joint from deteriorating.

[0033] According to a more particular embodiment, the means for axially positioning the clamping collar on the retention ring are constituted by an annular groove, and / or two series of positioning ears projecting radially from said annular portion and delimiting an annular zone for receiving the clamping collar.

[0034] Such a solution has the advantage of being particularly simple to implement, in addition to guaranteeing easy positioning of the collar during assembly.

[0035] According to one variant, the retention ring is made from a single piece.

[0036] According to a particular variant, the retention ring is made of plastic material, and preferably polyamide.

[0037] In this way, the manufacturing of the retention ring can be carried out simply, in a single step, without requiring a step of connecting added parts. In particular, the use of a plastic material, such as polyamide, and which can be loaded with a reinforcing material, such as fiberglass, allows the production of the retention ring in a simple and economical manner by molding, for example, or by any other known technique.

[0038] The invention also relates to a protective bellows for a transmission joint comprising a retention ring according to the invention, said retention ring being arranged on one end of the protective bellows.

[0039] According to an advantageous embodiment, the bellows comprises an axial stop for axial positioning of said retention ring in the form of a ring, or at least two positioning ears, said axial positioning stop forming an axial stop with said retention collar.

[0040] Thus, when the retaining ring and the bellows are packaged together, the installation of the bellows by the operator responsible for mounting the bellows and the retaining ring on the transmission joint is accelerated. Indeed, the operator will not have to make any effort to find the correct positioning of the retaining ring, the latter being already positioned on the end of the protective bellows, and cannot slide further onto the bellows. Thus, the retaining ring is already precisely positioned when the operator takes hold of it for assembly.

[0041] Finally, the invention also relates to a transmission assembly comprising a transmission joint, which may be of the Rzeppa type, comprising a bowl, on which is fixed a protective bellows comprising a retention ring according to the invention, said bellows and said retention ring being fixed to said bowl by means of a clamping collar.

[0042] The invention is implemented according to the embodiments and variants set out below, which are to be considered individually or in any technically effective combination. BRIEF DESCRIPTION OF THE FIGURES

[0043] Other advantages, aims and particular characteristics of the present invention will emerge from the following non-limiting description of at least one particular embodiment of the devices and methods which are the subject of the present invention, with reference to the appended drawings, in which: there [ Fig 1 ] is a perspective view of a transmission assembly comprising a retention ring according to the invention, the [ Fig 2 ] is a sectional view of the transmission assembly of the Figure 1 , according to a plane passing through two of the through slits, the [ Fig 3 ] is a perspective view of a retention ring according to the invention, the [ Fig 4 ] is a view of one side of the retaining ring of the Figure 3 . DETAILED DESCRIPTION OF THE INVENTION

[0044] This description is given without limitation, each characteristic of an embodiment or variant being able to be combined with any other characteristic of any other embodiment or variant in an advantageous manner.

[0045] Please note, from now on, that the figures are not to scale.

[0046] As shown in the non-limiting example of figures 1 And 2, a transmission assembly 400 comprises a transmission joint 200 between two shafts, a first shaft being secured to a bowl 210 of the transmission joint 200, and a second shaft being secured to a nut 220 of the transmission joint 200. The bowl 210 and the nut 220 comprise rails or grooves in which balls 230 are arranged. The balls 230 thus allow a bent position of the shafts, but do not leave any degree of freedom in rotation around the axes of the shafts. In this way, a rotational movement, and a torque can be transmitted by the transmission joint 200. A family of this type of transmission joints is known as "Rzeppa joint", from the name of their inventor.

[0047] The part of the transmission joint 200 on the side of the nut 220 is preferably protected by a protective bellows 300. Such a bellows is, in a known manner, a sheath of flexible material folded in an accordion, comprising an opening of reduced diameter corresponding to the diameter of the second shaft secured to the nut 220, and an opening of larger diameter corresponding to the external diameter of the bowl 210. In general, the protective bellows 300 is held in position by means of clamping collars (not shown) arranged near the openings.

[0048] In the example of realization of the figures 1 And 2 , a ring 100 for retaining balls of the transmission joint 200 is arranged on one end 310 of the protective bellows 300, the end 310 being the one comprising the opening of larger diameter.

[0049] The retaining ring 100 comprises a deformable annular portion 110, of diameter D1, adapted to receive a clamping collar of the bellows 300 on the transmission joint 200.

[0050] The retention ring 100 also comprises a retention collar 120 extending towards the inside of the retention ring 100, so as to form a retention stop for the balls 230 of the transmission joint 200, aimed at preventing the axial exit of the balls 230 from the transmission joint 200.

[0051] We understand, as it is visible on the Figure 2 , that the balls 230 do not abut directly against the retaining collar 120, but against the internal surface of the bellows 300, however it is the retaining collar 120 which makes it possible to perform the stop function, by its relative rigidity, the bellows 300 itself being too flexible to prevent the balls 230 from coming out of the bowl 210.

[0052] As can be seen in the Figure 2 , the retention collar 120 has an internal surface portion of generally truncated cone shape, open in the direction of the balls 230 of the transmission joint 200 when the ring is mounted on the bellows 300.

[0053] It is therefore understood that the balls 230 face a truncated surface which prevents them from escaping axially, the diameter at the level of the truncated surface decreasing the further one moves axially away from the bowl 210.

[0054] Thus, the retention collar 120 has a side with an upper diameter D1, corresponding to the diameter D1 of the annular portion, and a side with a lower diameter D2, which is less than the upper diameter D1.

[0055] In this way, the diameter of the retention collar 120 decreases in the direction from the side with the larger diameter D1 to the side with the smaller diameter D2.

[0056] In order to produce a stop, it is understood that it is necessary for the lower diameter D2 of the collar 120 to be less than the internal diameter of the bowl 210, that is to say less than the diameter of the circle to which the bottoms of the rails or grooves of the bowl 210 are tangent.

[0057] It is understood that thus, the balls 230 which would be likely to exit axially from the bowl 210 abut against the retaining collar 120, preserving the integrity of the transmission joint 200.

[0058] As can be seen on the figures 3 And 4 , the retention collar 120 is linked to the annular portion 110 by the side of greater diameter D1, so as to form a retention ring 100 of diameter D1, then decreasing towards the lower diameter D2, in the direction going from the annular portion 110 towards the retention collar 120.

[0059] In particular, the connection is a material connection, that is to say that the retention ring 100 is made from a single piece, although a two-part construction is possible (and the two parts are then connected together). The material constituting the retention ring 100 may be a plastic material, such as for example polyamide, which may be loaded with a reinforcing material, such as fiberglass.

[0060] In this way, the retention ring 100 is produced in a single step, by molding for example, at lower cost.

[0061] As is also visible on the figures 3 And 4 , the deformable annular portion 110 consists of a tubular wall 111 comprising at least one slot 112, made in an axial direction of the retention ring 100, so as to reduce the rigidity of the annular portion 110.

[0062] In this way, it is possible to arrange and tighten a clamp on the annular portion 110, the clamp enclosing both the annular portion 110 and the bellows 300 on the bowl 210. It is understood that in the absence of the through slot(s) 112, the rigidity of the annular portion 110 would prevent any tightening of the annular portion.

[0063] Preferably, the tubular wall 111 comprises four through slots 112 distributed regularly over the tubular wall 111, although it is possible to have a smaller or larger number of them. The presence of four through slots 112 guarantees good flexibility of the annular portion 110 while avoiding making it too fragile.

[0064] In addition, the deformable annular portion 110 comprises, on its outer surface, means for axially positioning the clamping collar on the retaining ring 100. In particular, positioning means acting as stops can be chosen.

[0065] Such means for axial positioning of the clamping collar are for example constituted by an annular groove 113 made in the tubular wall 111, on its outer side. It is understood that the width of the groove 113 is at least equal to the width of the clamping collar, so that the edges of the groove 113 delimit a positioning zone of the clamping collar, forming a stop with the latter.

[0066] Such axial positioning means for the clamping collar are also constituted (in isolation or in combination with the groove 113) by one or two series of positioning lugs projecting radially from the annular portion 110, so as to form a stop with the clamping collar. When there is only one series 114 or 115, the clamping collar is positioned axially in only one direction, whereas when there are two series 114 and 115, the series delimit an annular zone for receiving the clamping collar.

[0067] In particular, the ears of the series of positioning ears 114 and 115 are flush with the edge of the groove 113, when these two positioning means are implemented jointly. In other words, the positioning area of ​​the clamping collar defined by the groove 113 corresponds in this case to the annular receiving area of ​​the clamping collar defined between the series of positioning ears 114 and 115, resulting in a greater height stop at the positioning ears, and thus in a more secure axial positioning of the clamping collar.

[0068] It is therefore understood that the retaining ring 100 fulfills its role of retaining the balls 230 by being fixed to the outside of the bowl 210 by its annular portion 110, the balls being retained by the retaining collar 120. The annular portion 110 is itself fixed to the bowl 210 but also serves as an intermediate fixing for the protective bellows 300. The retaining collar 120 retains the balls 230, thus forming a retention stop.

[0069] Advantageously, the protective bellows 300 is adapted to accommodate the retention ring 100, in particular with regard to its axial positioning on the protective bellows 300.

[0070] For this purpose, the protective bellows 300 comprises an axial positioning stop for the ring 100 in the form of at least two lugs 320 for axial positioning of the retaining ring 100, the positioning lugs 320 forming an axial stop with the retaining collar 120. Of course, the lugs 320 can take any shape capable of forming an axial stop, the shape shown in particular in FIG. Figure 1 not being limiting.

[0071] As it is visible on the figures 1 And 2 , the retaining ring 100 is thus held on the end 310 without risk of sliding further onto the bellows 300.

[0072] According to a variant not shown, the bellows 300 comprises an axial stop for axial positioning of the retention ring 100 in the form of an axial positioning ring.

[0073] It is specified that such axial positioning is particularly advantageous when the retention ring 100 and the bellows 300 are packaged together, with a view to their implementation in a transmission assembly 400. Indeed, the operator responsible for mounting the bellows 300 and the retention ring 100 will not have to make any effort to find the correct positioning of the retention ring 100, the mounting thus being made easier and faster.

[0074] When the clamp has been tightened onto the retaining ring 100, the locating ears 320 or the axial locating ring are no longer essential for axial positioning, the clamp providing axial and radial position retention.

Claims

1. Ring (100) for retaining balls (230) of a ball transmission joint (200), adapted to be mounted on one end (310) of a bellows (300) for protecting the transmission joint, characterised in that said retaining ring includes: • a deformable annular portion (110), of constant diameter, adapted to receive a collar for clamping said bellows on said transmission joint, and • a retaining flange (120) extending into the retaining ring, so as to form a stop for retaining the balls of the transmission joint, preventing the axial exit of said balls out of the transmission joint.

2. Retaining ring (100) according to claim 1, wherein the retaining flange (120) has an inner surface portion at which the diameter of the flange decreases on moving axially further away from a bowl (210) of the transmission joint (200), when the ring is mounted on said bellows (300).

3. Retaining ring (100) according to any one of claims 1 or 2, wherein the deformable annular portion (110) is formed of a tubular wall (111) including at least one through slot (112) created along an axial direction of the ring, so as to decrease the rigidity of said annular portion.

4. Retaining ring (100) according to claim 3, wherein the tubular wall (111) includes four through slots (112) evenly distributed along said tubular wall.

5. Retaining ring (100) according to any one of claims 1 to 4, wherein the deformable annular portion (110) includes, on its outer surface, axial positioning means (113, 114, 115) of said clamping collar on said retaining ring.

6. Retaining ring (100) according to claim 5, wherein the axial positioning means of the clamping collar on the retaining ring are formed of an annular groove (113), and / or two series (114, 115) of positioning lugs protruding radially from said annular portion (110) and delimiting an annular area for receiving the clamping collar.

7. Retaining ring (100) according to any one of claims 1 to 6, the retaining ring being made of one piece.

8. Retaining ring (100) according to any one of claims 1 to 7, the retaining ring being made of plastic material, and preferably of polyamide, preferably charged with glass fibre.

9. Bellows (300) for protecting a transmission joint including a retaining ring (100) according to any one of claims 1 to 8, said retaining ring being disposed on one end (310) of the protective bellows.

10. Bellows (300) according to claim 9, including an axial positioning stop of said retaining ring (100) in the shape of a ring, or at least two positioning lugs (320), said axial positioning stop forming an axial stop with said retaining flange (120).

11. Transmission assembly (400) comprising a ball transmission joint (200), including a bowl (210), to which a protective bellows (300) including a retaining ring (100) according to any one of claims 1 to 8 is attached, said bellows and said retaining ring being attached to said bowl by means of a clamping collar.