FR2744775A1 - TRANSMISSION SHAFT WITH INTERMEDIATE BEARING - Google Patents

Abstract

A transmission shaft, in particular intended to be used in a utility vehicle as a longitudinal shaft, comprises at least two shaft sections and an intermediate bearing 15. With a view to obtaining an operation devoid of vibrations and avoiding a reciprocal influence of the intermediate bearing 15 relative to the sliding, the bearing 18 is mounted on a section of the sliding sleeve 9, which does not transmit torque forces, that is to say which does not have teeth. The corresponding bore section of the sliding sleeve is in the form of a cylindrical bore. The toothing 11 does not start until after the bearing 18. Furthermore, the bearing 18 is stopped on the sliding sleeve, by means of a stopper 28 "supporting two sealing rings 31 and 40 ensuring the sealing of the bearing and of the gap between the sliding sleeve and the sliding journal 6. This makes it possible to reduce the distance from the median plane of the bearing 18 to the center of flexure of the articulated joint 3.

Description

The invention relates to a drive shaft composed of at least two

  shaft sections, of which the first shaft section comprises two articulated joints, a tube connecting the articulated joints, as well as a profiled sliding journal which is connected to one of the articulated joints, and of which the second shaft section includes an articulated joint, a sliding sleeve having a bore, which comes from a free front surface of the sliding sleeve and comprises a section adapted to the sliding pin, as well as a tube connecting them, the transmission shaft also being composed of '' an intermediate bearing comprising a bearing, which, by its inner ring, is held in a non-sliding manner in the direction of the longitudinal axis of the second section of shaft, on an adjusted bearing surface of the sliding sleeve, in the vicinity of the

  articulated joint to which the sliding pin is connected.

  Such a drive shaft is described in French patent 897,516 (publication number 1,330,805). In this case, the inner race of the bearing is an integral part of the outer surface of the sliding sleeve. Sliding takes place directly in a sliding profile under the raceway of the bearing. The bearing is in the form of a grooved ball bearing, and the axial stop is effected by means of the internal raceway. This measurement certainly makes it possible to obtain a relatively short distance between the articulated joint comprising the sliding journal, namely the bending center thereof, and the median plane of the bearing, but a disadvantage of this arrangement however lies in the fact that '' due to the sliding profile, the operating properties of the

  bearing are affected when a torque is transmitted.

  Indeed, the operating clearances vary when

torque is transmitted.

  In document DE 30 14 790 C2, a transmission shaft is described in which the bearing is separated from the associated shaft section, by the fact that there is provided a separate inner bearing race. In the case of the construction method chosen here, the distance between the bearing and the neighboring cross joint is still relatively large, despite an improvement compared to known solutions, this due to the flange connection existing between them, and integration of the sliding in the other section of the shaft. In addition, the choice of flange connection,

  causes a considerable increase in weight.

  To obtain low-vibration operation of the articulated drive shaft, it is important that the intermediate bearing perfectly performs its function. For this purpose, it is necessary to guarantee relatively tight tolerances as to the adjustment of the bearing, namely in particular as to the adjustment of the inner ring of the bearing on the associated part of the shaft section. However, in order to ensure the proper functioning of the bearing in a lasting manner, the function of the bearing must not be affected by the transmission of torque either. The magnitude of the distance between the bearing bearing plane and the bending center of the neighboring articulated joint is also significant for obtaining operation at low vibrations. Conversely, the bearing should not influence the sliding either. The object of the invention therefore consists in indicating a transmission shaft of the type of that mentioned in the introduction, which makes it possible to best satisfy the

  requirements and conditions which have just been mentioned.

  According to the invention, this object is achieved by the following solution, characterized in that the inner ring is fixed between a shoulder of the adjusted bearing surface or the bearing surface of a separate stop element, and a stopper cap, in that the stopper cap is engaged on the adjusted bearing surface of the sliding sleeve, from the free front surface of the latter, the stopper cap comprising a stopper section, which bears against the inner ring in the direction of the longitudinal axis, and having a recess in which is disposed a first sealing ring serving to seal the bearing, in that the stopper is fixed on the sliding sleeve by fixing means, and in that the bore of the sliding sleeve is not profiled in the area located under the

rolling.

  The advantage of this configuration lies in the fact that the integration of the sealing ring in the stopper cap, and the use of the latter for the axial fixing of the inner ring of the bearing, make it possible to guarantee good suitability for mounting, as well as a compact design in the axial direction. The distance between the median bearing plane of the bearing and the center of flexure of the articulated joint is relatively short. Having the toothed bore section of the sliding sleeve outside the area under the bearing provides silent and uniform operation, because it is possible to guarantee an adjustment with close tolerances and uniforms of the inner race of the bearing on the sliding sleeve, without being influenced by the adjustment of the bearing on the sliding function. There is no influence on the sliding movement of the sliding sleeve in the profiled section of the bore, nor vice versa, during the transmission of the torque, of the profile on the function of the bearing. The offset of the profiled area has no influence on the length of the corresponding shaft section, since in general there is anyway a tube to establish the connection between the

  sliding sleeve and associated articulated joint.

  Overall, thanks to the proposed measures, a low vibration operation of the transmission shaft is obtained, which also makes it possible to simplify the balancing of the transmission line, which is

  always particularly delicate.

  According to a configuration of the invention, it is provided that the stop cap has an extension, which receives a second sealing ring intended to seal the sliding sleeve relative to

sliding journal.

  The advantage of this resides in the fact that the distance between the median bearing plane of the bearing and the center of the neighboring articulated joint can be reduced even more, while simplifying the assembly and satisfying the requirements of the market, as regards lines

  as short as possible.

  According to one embodiment, the extension has a collar directed radially inwards relative to the longitudinal axis. The second sealing ring is clamped between the flange and the front surface of the sliding sleeve. It has sealing lips intended to come to bear on the sliding pin. In this case, one of the sealing lips can act as a primary seal, in order to scrape off the deposits of dirt, by

  example on the surface of the sliding sleeve.

  Overall, a sealed system is obtained, because the second sealing ring also closes a possible gap between the bore of the stopper and the bearing surface of the sliding sleeve, so that grease cannot get escape out of the bearing, through this gap, moisture and dirt from the outside can not either enter the

landing at this location.

  The recess of the stopper cap intended to receive the first sealing ring is preferably of an annular configuration. It is open towards the bearing. Furthermore, it has stopping protuberances for stopping the first sealing ring, so that a kind of undercut is produced in which can

  snap on the first sealing ring.

  To allow, during rotation, the ejection of dirt from the bearing, it is provided according to a configuration of the invention, that the radially outer wall limiting the recess for the first sealing ring, has a section s' flaring conically with respect to the longitudinal axis, in the direction of the opposite bearing surface for a sealing lip of the first sealing ring. According to a first configuration variant, according to which the stop cap receives only the first sealing ring, the stop cap is held by a stop ring engaging in a groove in the adjusted bearing surface of the sliding sleeve. As a variant, the stop cap is provided on its front surface, opposite that of the stop section, with stop heels intended to engage in a groove in the adjusted bearing surface of the sliding sleeve. Finally, it is also possible to provide the stopper cap, in its bore by which it

  rests on the adjusted bearing surface, of a thread.

  Likewise, a thread is provided on the adjusted bearing surface. The stop cap is therefore screwed by its thread, onto the thread of the adjusted bearing surface of the sliding sleeve, the two together forming the stop means. The thread pitch can be chosen so as to obtain a connection which cannot loosen by itself. Finally, in order to obtain ventilation as well as a possibility of lubricating the intermediate bearing, even in the case where the second sealing ring is supported by the stopper, several channels are provided in the stopper , which are distributed around the periphery and extend parallel to the longitudinal axis. These channels originate from the front surface opposite that of the stop section, and each extend at least until the thread of

the bore of the cap.

  In this case it is advantageous that the threads of the thread form a throttling channel. The size of the throttle channel can be influenced by the fact that the thread of the sliding sleeve, on the outside diameter, and / or the thread of the stopper, on the inside diameter, are provided with a flat, and the two together forming a space passage channel

free thus created.

  To facilitate the mounting of the stopper cap, in the outer surface and / or the front surface of the collar of the stopper cap, are provided, distributed around the longitudinal axis,

  recesses used to hold a tool.

  The stopper cap is preferably made of a plastic material. The plastic considered is formed by a plastic from the group of polyamide 6 containing a portion of glass fibers, in order to achieve the necessary strength. The choice of this material allows a particularly economical manufacture and suitable for recycling the stopper cap, while guaranteeing the necessary resistance. Preferred exemplary embodiments of the invention and a transmission shaft made up of two sections of shafts are explained in more detail with reference to the appended drawings in which they are shown diagrammatically, the drawings showing: FIG. 1 a transmission shaft in the extended position, composed of two shaft sections, and comprising an intermediate bearing, FIG. 2 is a longitudinal half-section limited to the arrangement of the intermediate bearing, on an enlarged scale with respect to FIG. 1, FIG. 3 a variant of FIG. 2, relating to the stop cap on the sliding sleeve, as a detail, FIG. 4 an embodiment according to which the stopping of the second sealing ring is also ensured by the stopping cap, and FIG. 5 the stopper cap of the embodiment according to FIG. 4, as a longitudinal half-section, on an enlarged scale with respect to

in Figure 4.

  FIG. 1 shows a transmission shaft comprising the two shaft sections 1 and 2. The first shaft section 1 comprises the two articulated joints 3, 4, which in the case of the present exemplary embodiment are in the form of universal cross joints, as well as the tube 5 connecting these two articulated joints. To the articulated joint 3 is connected the sliding pin 6, which is provided with a toothing 7 at its free end, that is to say the end opposite to

that of the articulated joint 3.

  The second shaft section 2 includes the articulated joint 8, which is also in the form of a universal cross joint, and the sliding sleeve 9, as well as the tube 12 which connects them. The sliding sleeve 9 is provided with a bore 10, which has, first of all, a cylindrical bore section, that is to say not profiled, which comes from the front surface 13, which is then connected, in direction of the articulated joint 8, to a toothing 11. The sliding pin 6 is housed, through its toothing 7, in the toothing 11 of the sliding sleeve 9, so as to be able to slide in the direction of the axis longitudinal X. The two shaft sections 1, 2 are shown in their extended position, that is to say that the seals are not in the bending position. The two articulated joints 4, 8 are each provided with a flange serving for the connection on the one hand to a driving part of a motor vehicle and to a part to be driven. Such drive shafts are preferably used as a longitudinal drive shaft in motor vehicles and serve, for example, to ensure the continued transmission of torque from the gearbox to the differential between the rear wheels of a commercial vehicle. To ensure reliable rotational mounting, an intermediate bearing 15 is also provided, which is intended to be fixed to the chassis of the motor vehicle. The intermediate bearing 15 comprises a casing 16 comprising a bearing body 17 made of an elastic material, intended for damping vibrations. The bearing body 17 serves to receive the bearing 18, the inner ring of which is fixedly mounted on an adjusted bearing surface of the sliding sleeve 9. The distance from the bearing, namely the distance between the median plane of the bearing 18 and the center of flexion of the adjacent universal cross-member 3 is designated by the reference mark L. The magnitude of this distance influences the quality of the operation of the drive shaft. In the case of the embodiment according to the invention and

  shown, this distance is extremely short.

  FIG. 2 gives a glimpse, on an enlarged scale, of the particular arrangement of the intermediate bearing 15 with respect to the sliding sleeve 9 and to the bending center of the articulated joint 3. know the fork of the joint connected to the sliding pin 6 carrying the toothing 7. In this case, the sliding pin 6 is in the fitted position relative to the toothing 11 of the sliding sleeve 9. Furthermore, it is visible that under the surface of adjusted range 20 of the sliding sleeve 9, intended for the intermediate bearing 15, there is a bore 14 first of all cylindrical, coming from the front surface 13. Seen from the front surface 13, the inner ring 19, with which the bearing 18 in the form of a grooved ball bearing, is mounted on the adjusted bearing surface 20 of the outer surface of the sliding sleeve 9, is arranged before the toothing 11. Therefore, adjusts ment with which the inner ring 19 is mounted on the adjusted bearing surface 20, can also have a tightening, without influencing the function of the sliding effected by the two teeth 7, 11. Conversely, these do not exert either negative influences on the function of the bearing 18, during the transmission of the torque between the sliding sleeve 9 and the sliding journal 6. The outer ring of the bearing 18 is housed in two sheet metal inserts 22, 23, which each have a section s 'extending parallel to the longitudinal axis X, and by which they are received in the bearing body 17. From this section come flange sections directed radially inwardly, and surrounding the bearing 18 at a distance. The adjusted bearing surface 20 ends with a shoulder 21 coming from the front surface 13. On this adjusted bearing surface is first reported a sheet metal ring 24 which is applied against the shoulder 21 and forms a bearing surface 26 on which the ring rests

  interior 19 with its first front surface 25.

  The sheet metal ring 24 also serves to receive a sealing ring whose sealing lip seals with respect to the external surface of the section of the sheet metal insert 22, oriented radially inwards. . Furthermore, the inner ring 19 is held against sliding in the direction of the longitudinal axis X, by a stop cap 28 on the adjusted bearing surface. This stop cap is supported, by a stop section 29, on the

  second front surface 27 of the inner ring 19.

  The stop cap 28 is held in its position, by a stop ring 34 received in a groove 33, in the

  adjusted bearing surface 20 of the sliding sleeve 9.

  Furthermore, the stopper 28 has an annular recess 30, which is open in the direction of the surface of the sheet metal insert 23, directed radially inwards, and in which a first ring is received. sealing 31. This comprises a sealing lip 32 intended to be applied to the external surface of the sheet metal insert 23. The first sealing ring 31 is held in the recess 30, by protrusions of stop 37, produced in such a way that an undercut is formed. The recess 30 is limited radially to the outside by a wall 38 which, from a cylindrical section, is connected to a wall section 38a which widens conically and is directed towards the outside. This conical section is used to eject dirt outwards during rotation and also to prevent the penetration of dirt. The stop ring 34 is supported on the front surface 35 of the stop cap 28. Furthermore, on the end of the sliding sleeve 9 coming from the front surface 13, is fitted a sealing cap 39 serving for the support a second sealing ring 40 comprising sealing lips 42 intended to ensure the sealing with respect to the groove 41 of the sliding journal 6. Both the stopper 28 and the sealing cap 39 are made of plastic. The stopper 28 is preferably made of a material from the group of polyamides, namely those of quality 6, the material being reinforced by fillers, namely a glass fiber content. Thanks to the stop cap 28 intended for the axial stop, it is also possible to compensate for tolerances, to a greater extent. This arrangement leads to a length L, namely the distance between the median bearing plane and the center of

  bending of the articulated joint, relatively short.

  FIG. 3 shows in detail a variant configuration for stopping the stopper 28 'on the adjusted bearing surface 20. The stopper 28', starting from its front surface, is mounted on the adjusted bearing surface 20 and has stopping heels 43 protruding inwards in the direction of its bore 36; these stopping heels are provided on the front surface 35, in a distributed manner in the peripheral direction with reference to the longitudinal axis X. These heels serve to snap into the groove 33. The stopping section 29 serves also, by coming to rest on a front surface of the inner ring 19, to maintain

the bearing 18 in its position.

  In the case of the embodiment according to FIGS. 4 and 5, the stopper 28 "also provides the function of supporting and fixing the second sealing ring 40. In addition, another mode is provided stopper 28 "on the adjusted bearing surface 20 of the sliding sleeve 9. For this purpose, the bore 36 of the stopper 28" is provided with a

  thread 44 coming from the end of the stopping section 29.

  The tops of the thread of the thread 44 are, as can be seen in FIG. 5, provided with a flat, so that after screwing the male part forms on the cap a complete thread serving for self-braking of the system. Furthermore, the stopper 28 "has, in the direction of the articulated joint 3, an extension 46, which ends towards the front surface 35 ', by a flange 47 directed radially inwards and forming an interior surface 48. In the collar 47, channels 49 coming from the front surface 35 'and extending up to the thread 44 are arranged in a distributed manner around the longitudinal axis X. The sliding sleeve 9 also includes a thread 45 coming from the front surface 13, and onto which is screwed, with its thread 44, the stopper 28 ". This keeps the second stop ring 40 tight between the inner surface 48 of the flange 47 of the stopper 28 "and the front surface 13 of the sliding sleeve 9. These measures make it possible to obtain an additional reduction in length. L. In addition, the thread provides the advantage of even greater compensation for tolerances, for fixing the bearing 18. For actuating the stopper 28 ", in the outer surface 50 of the extension 46 and in the front surface 35 'of the flange 47, are provided in a distributed manner on the periphery,

  recesses 51 used to hold a tool.

Claims (13)

CLAIMS.   1. Transmission shaft composed of at least two shaft sections (1, 2), the first shaft section (1) of which comprises two articulated joints (3, 4), a tube (5) connecting the articulated joints (3, 4), as well as a profiled sliding journal (6), which is connected to one (3) of the articulated joints (3, 4), and the second section of the shaft (2) of which comprises a joint articulated (8), a sliding sleeve (9) having a bore 10), which comes from a free front surface (13) of the sliding sleeve (9) and comprises a section adapted to the sliding pin (6), as well as a tube (12) connecting them, the drive shaft also being composed of an intermediate bearing (15) comprising a bearing (18), which, by its inner ring (19), is held in a non-sliding manner in the direction from the longitudinal axis (X) of the second shaft section (2), on an adjusted bearing surface (20) of the sliding sleeve (9), in the vicinity of the articulated joint (3) to which the barrel is connected lon sliding (6), characterized in that the inner ring (19) is fixed between a shoulder (21) of the adjusted bearing surface (20) or the bearing surface (26) of a stop element ( 24) separate, and a stopper cap (28, 28 ', 28' '), in that the stopper cap (28, 28', 28 '') is engaged on the adjusted bearing surface (20) of the sliding sleeve (9), from the free front surface (13) thereof, the stop cap comprising a stop section (29), which bears against the inner ring (19) in the direction of the longitudinal axis (X), and having a recess (30) in which is disposed a first sealing ring (31) serving to seal the bearing (18), in that the stopper cap (28, 28 ', 28 ") is fixed to the sliding sleeve (9) by fixing means (33, 34, 43, 44, 45), and in that the bore (10) of the sliding sleeve (9 ) is not profiled in the area under the bearing (18).   2. Transmission shaft according to claim 1, characterized in that the stopper cap (28 ") has an extension (46), which receives a second sealing ring (40) intended to seal the sliding sleeve (9) compared to sliding pin (6).   3. Drive shaft according to claim 2, characterized in that the extension (46) has a flange (47) directed radially inwards relative to the longitudinal axis (X), and in that the second ring d the seal (40) is clamped between the flange (47) and the front surface (13) of the sliding sleeve (9), and has sealing lips (42) intended to come to bear on the sliding pin (6).   4. Transmission shaft according to claim 1, characterized in that the recess (30) of the stopper cap (28, 28 ', 28 ") is of an annular configuration and is open in the direction of the bearing (18) , and in that stop protrusions (37) are provided in the recess (30), to achieve   stopping the first sealing ring (31).   5. Drive shaft according to claim 1, characterized in that the radially outer wall (38) limiting the recess (30) for the first sealing ring (31), has a section (38a) flaring so conical with respect to the longitudinal axis (X), in the direction of the opposite bearing surface for a sealing lip (32) of the first sealing ring (31).   6. Transmission shaft according to claim 1, characterized in that the stop cap (28) is held by a stop ring (34) engaging in a groove (33) in the surface of   adjusted bearing surface (20) of the sliding sleeve (9).   7. Transmission shaft according to claim 1, characterized in that the stop cap (28 ') is provided on its front surface (35) opposite that of the stop section (29), heels d 'stop (43) intended to engage in a groove (33) in the adjusted bearing surface (20) of the sleeve sliding (9).   8. Drive shaft according to one of   Claims 1 to 5, characterized in that the cap   stop (28 "), in its bore (36) by which it rests on the adjusted bearing surface (20), is provided with a thread (44), and is screwed onto a thread (45) on the surface adjusted bearing (20) of the sliding sleeve (9), the two together forming the means stop.   9. Drive shaft according to claim 8, characterized in that in the stop cap (28 ") are provided several channels (49), which are distributed around the periphery and extend parallel to the longitudinal axis (X) , and which come from the front surface (35 ') opposite that of the stopping section (29), and each extend at least up to thread (44) of the bore (36).   10. Transmission shaft according to claim 9, characterized in that the thread (45) of the sliding sleeve (9), on the outside diameter and / or the thread (44) of the stopper cap (28 "), on the internal diameter, are provided with a flat, and the two forming together a passage channel in space free thus created.   11. Drive shaft according to one of   claims 8 to 10, characterized in that in the   external surface (50) and / or the front surface (35 ') of the flange (47) of the stopper cap (28 "), are provided, in a manner distributed around the longitudinal axis (X), recesses ( 51) serving as a socket for a tool.   12. Drive shaft according to one of   Claims 1 to 11, characterized in that the cap   stop (28, 28 ', 28 ") is made of a material plastic.   13. Transmission shaft according to claim 12, characterized in that the plastic material is formed by polyamide 6 containing a share of glass fibers.