FR2685040A1 - TRANSMISSION SHAFT COMPRISING A JOINT AND A HOLLOW BAR HOUSING A HEAT COOLING MEDIUM. - Google Patents

Abstract

The invention relates to a drive shaft comprising a seal (4, 4 ') and a bar (3) which is exposed to the wind of the step. In the bar (3) of the shaft is arranged, at least in the region of the seal (4, 4 '), a heat exchange tube which extends into the bar inside and outside of the region of the seal (4, 4 '), a vaporization zone (9) of the heat exchange tube being placed in the region of the seal (4, 4') and a condensation zone (10) of this tube of heat exchange being placed in the region of the bar (3) which is exposed to the wind of the step.

Description

The invention relates to a drive shaft such as that which is known.

  by the journal ATZ (Automobiltechnische Zeitschift) 80, N O 11, 1978, page 513, by S L Girgus: "DOS Ein neues Gleichlaufgelenk fur Kraftfahrzeug-Antriebe" ("DOS a new CV joint for vehicle transmissions

  automobiles "), in particular Figure 2.

  The drive shaft in question is associated with a vehicle axle and, in its mounting position, two hollow articulated drive shafts extend from a differential interposed between them up to the wheels of the vehicle, located outside Each drive shaft has two seals, one seal being arranged near the vehicle wheel and the other approximately in the middle, in the region of the differential. Each seal is subdivided into a ring provided on its outer circumference and a hub disposed centrally in the joint, with transmission balls and a guide cage interposed radially between the ring and the hub The cooling of the two hubs of the joints of each transmission shaft is ensured in particular by a bar which is in most of the case freely exposed to the wind of the step and which also connects the two hubs of the joints of the same drive shaft The cooling of the joints

  trees is insufficient in the case of large loads.

  As a result, the temperature of the lubricant may rise to an unacceptably high extent and the lubrication may be insufficient. Likewise, the permissible temperatures of the sealing members such as, for example, the bellows, may be exceeded, so that here , it is necessary to use more expensive materials and / or constructions Up to now, we combat this overheating by increasing the volume of the components to ensure the absorption and evacuation of heat However, this increases the weight and the '' space

  of the joint, which is undesirable in many cases.

  Moreover, in many construction cases, an increase in the dimensions of the components cannot eliminate the difficulty because the mounting area causes additional heating of the joint, for example

  due to the proximity of the exhaust.

  It is known, from DE-A-30 25 731, to cool the brake discs and the outer seals of the shafts, to provide the wheel hub with drilled holes oriented radially and inclined inwards, towards the In operation, the holes behave like a radial fan, and the brake disc and the wheel bearing which follows it and the shaft seal receive an air flow It would be disadvantageous to adopt a similar solution for the inner seal which in most cases undergoes greater thermal stress, both for reasons of weight and for reasons of the dimensions of the components. Furthermore, this method of cooling the outer seal of the shaft is also unsatisfactory. because the running noise is increased, due to the turbulence of the incoming air, which occurs during walking. Furthermore, the propulsion energy consumption is increased by increasing the

resistance to walking.

  The object of the invention is to improve the already known drive shaft so that the lubrication of the shaft seal remains ensured, even under high load by using small components for

the drive shaft.

  According to the invention, this problem is solved with a drive shaft having at least one shaft seal and a bar associated with the joint and exposed to the gait wind, characterized in that, in the bar of the transmission shaft , is arranged, at least in the region of the joint, a heat exchange tube which extends into the shaft of the shaft, inside and outside the region of the joint, a vaporization zone of the heat exchange tube being disposed in the region of the joint and a condensing zone of the heat exchange tube being disposed in the region of the bar of the tree which undergoes the action of the wind of the step Thanks to the incorporation of the heat exchange tube in the bar of the drive shaft, a lowering of the temperature level of the seal is obtained, for a predetermined dimension of the components and a predetermined load, compared to traditional seals. resu lte, we obtain, even under more severe working conditions, reliable lubrication, a greater expectation of durability of the seals and a lower thermal stress of the bellows. Furthermore, for a predetermined load, we can admit smaller seals and lighter compared to an uncooled embodiment In the case of universal joint shafts or drive shafts for vehicle axles, the mass of the vehicle is reduced and, in this way, the consumption of energy for propulsion is reduced indirectly and this results in a lower load for the environment and for energy reserves Thanks to the reduction in weight, at least of the weight of the shaft seal on the wheel side, we can also improve the walking comfort at the vehicle axles since the masses

  not suspended from the vehicle are reduced.

  According to preferred embodiments of the present invention: each seal of the shaft is divided into a ring situated at its outer periphery and a hub disposed in a central position in the seal, the bar of the shaft being rigidly secured to the hub; the heat exchange tube integrated in the shaft bar extends over the entire length of the shaft bar which is provided with seals at its two ends, as far as the region of the two seals, however, in the region of each joint is arranged a vaporization zone of the heat exchange tube; the bar which is hollowed out by a bore is hermetically closed at its front ends by a shut-off ball force-fitted; the vaporization zone of the heat exchange tube which is located in the region of the joint has a fitted felt sleeve which extends into the region of the condensation zone; the vaporization zone of the heat exchange tube which is in the region of the joint has an annular retaining disc which is placed at the end of the condensation zone directed towards the vaporization zone, and separates these zones one the other; the retaining disc is funnel-shaped, with the point of the funnel pointing towards the vaporization zone; the drive shaft is a drive axle for a vehicle axle, carrying drive wheels, with independent suspension, with at least one constant velocity joint and a shaft bar exposed to the gait wind; the shaft bar is provided with cooling fins in the region of the condensation zone; the cooling fins are formed by cooling discs force-fitted on the outer periphery of the shaft bar or by a cooling fin wound on the outer periphery. Furthermore, the invention is described more fully below in connection with exemplary embodiments shown in the drawings. In these drawings, FIG. 1 represents a drive shaft having a hollow shaft bar and seals associated with this bar. on both sides;

  FIG. 2 shows a vehicle axle comprising

  taking two drive shafts, in the mounting position; FIG. 3 represents an enlarged detail of an interior seal, with the vaporization zone; and

  FIG. 4 represents another mode of construction.

  tion of the vaporization zone of a joint; Figure 5 shows the drive shaft with cooling discs arranged in a condensing region; and Figure 6 shows the drive shaft with a cooling zone developed in the condensation region.

  In Figure 1, a trans-

  motor vehicle mission 2 such as that used, for example, in vehicles equipped with drive wheels 16 with independent suspension Here, at each of the wheels 16 of

  the axle 1 of the vehicle is associated with a transmission shaft

  sion 2 which extends from a differential 17 arranged approximately

  in the central position up to the outer wheel 16 of the vehicle

  The invention is also advantageous in the case

  vehicle axles in which the differential is ex-

  centered An outer seal 4 'of the shaft is arranged outside

  laughing, in the region of the wheel 16, and the seal 4 side

  inner tree tee is located roughly in the middle,

  against the differential 17 To be protected from dirt

  re, each 4, 4 'joint of the shaft is covered on the side

  open, i.e. the axially movable side, here di-

  rection of the axis 3 of the shaft, of the bellows 13 of flexible material and, for protection against wear, each

  shaft seal 3 still has a reserve of lubricant

confident 12.

  The seals 4, 4 'have a seal ring 6 at their outer periphery, and a seal hub 5 disposed in a central position in the seal 4, 4', several balls

  transmission 7 being arranged, with their guide cage

  ge 8, between the ring 6 and the hub 5 During operation, these seals 4, 4 'are exposed to thermal stress; the resulting heating is removed from the bar 3 of the shaft, which connects the hubs 5 of the seals 4, 4 ', and which

  is exposed to a large extent to the gait wind.

  In the bar 3 of the drive shaft 2, is arranged in the region of the inner seal 4 and the outer seal 4 ', a heat exchange tube which extends both inside and outside of the region of the seals 4,4 'The heat exchange tube, which is advantageously integrated in the bar 3 of the shaft in the case of use considered, is advantageously placed in the bar 3 of the shaft in such a way that its vaporization zone 9 extends in the region of the hub 5 of the seal and its condensation zone 10 in the region of the bar 3 of the shaft which is exposed to the wind of walking The heat exchange tube integrated in the bar 3 of the shaft advantageously extends over the entire length of the bar 3, as far as the region of the two seals 4,4 ′, while, in the region of each hub 5 of the seal, there is a zone of vaporization of the heat exchange tube In this way, the heat is removed from the two seals 4.4 ' a simple and effective way since the dissipation of latent heat occurs in the region exposed to the wind of the step. In order for effective cooling to occur, it is particularly advantageous to provide the bar 3 of the shaft with fins. cooling which enlarges its cooling surface in the region exposed to the wind of walking The cooling fins are formed by cooling discs 19 force fitted on the outer periphery of the bar 3 of the shaft in the region of the condensation zone 10, or else by a cooling fin 18 wound on this circumference Besides, the cooling fins can also be formed by ribs

  arranged in bar 3 of the tree.

  The heat exchange tube which is advantageously formed by a bore made axially and concentrically in the bar 3 of the shaft, is hermetically closed at its front ends by a shut-off ball 11 force-fitted. In this way, the tube is closed. heat exchange simple to set up, which has a simple constitution and which is however reliable These balls can be obtained at an economical price, with great shape accuracy and good surface quality However, depending on the case of application, it may be advantageous to close off the heat tube by a plug, a screw or by welding, brazing or the like To guarantee the safety of transport of the liquid heat transfer medium from the condensation zone 10 to the vaporization zone 9, it is desirable to provide the heat exchange tube with grooves acting as capillaries in its inner wall. The vaporization zone 9 of the heat exchange tube which is in the region of the hub 5 of the seal is kept wet by a felt sleeve 14 which extends into the region of the condensation zone 10, so that thus avoids drying or drying out of one of the two spray zones 9 which could result from the transverse inclination of the

tree bar 3.

  In another embodiment, also advantageous, a retaining disk 15 is placed at the end of the condensation zone 10 which is directed towards the vaporization zone 9, a disk which separates from the condensation zone 10 the vaporization zone 9 of the heat exchange tube which is located in the region of the hub 5 of the seal, so that the condensation zone 9 is kept moist. The retaining disc 15 is flared in a funnel, so that the point of the funnel is directed towards the vaporization zone 9, so that an improved passage is obtained

  or enhanced liquid flow to the vaporization zone

  sation 9 and better retention of the condensate therein

  flow, just as it can stop the reflux of conden-

  sat which has entered the condensation zone 10 In this construction, it may be advantageous to have not a single retaining disc 15 but several discs of

  retainer with mutual axial spacing in the

  transition region between spray zone 9 and

condensation zone 10.

Claims (6)

R E V E N D I C A T I O N S   1 drive shaft comprising at least one shaft seal and a bar secured to the joint and exposed to the wind, characterized in that, in the bar (3) of the drive shaft (2), is arranged, at least in the region of the seal (4, 4 '), a heat exchange tube which extends in this bar (3) of the shaft, inside and outside the region of the seal ( 4, 4 '), a vaporization zone (9) of the heat tube being arranged in the region of the joint (4, 4'), and a condensation zone (10) of the heat tube being disposed in the region of the exposed bar (3) of the tree in the wind.   2 drive shaft according to claim 1, characterized in that each seal (4, 4 '> of the shaft is divided into a ring (6) located at its outer periphery and a hub (5) disposed centrally in the joint (4, 4 '), the bar (3) of the shaft being rigidly integral with the hub (5).   3 transmission shaft according to claim 1, characterized in that the heat exchange tube integrated in the bar (3) of the shaft extends over the entire length of the bar (3) of the shaft which is provided of joints (4, 4 ') at its two ends, up to the region of the two joints (4, 4'), however, in the region of each joint (4, 4 ') is arranged a zone of   vaporization (9) of the heat exchange tube.   4 drive shaft according to claim 1, characterized in that the bar (3) which is hollowed out by a bore, is hermetically closed at its front ends   by a shut-off ball (11) force fitted.   Drive shaft according to claim 1, characterized   in that the vaporization zone (9) of the heat exchange tube which is situated in the region of the joint (4, 4 ′) 5 has a fitted felt sleeve which extends into the region of the condensation zone (10).   6 Transmission shaft according to claim 1, characterized in that the vaporization zone (9) of the heat exchange tube which is located in the region of the seal (4, 4 ′) has an annular retaining disc (15) which is placed at the end of the condensation zone (10) directed towards the vaporization zone (5), and separates these zones from each other. 15 7 Transmission shaft according to claim 6, characterized in that the retaining disc (15) is funnel-shaped, with the point of the funnel pointing towards the spraying zone (9) .20 8 Drive shaft according to claim 1, characterized   in that the drive shaft is a drive axle for a vehicle axle, carrying drive wheels, with independent suspension, with at least one constant velocity joint and a shaft bar exposed to the gait wind.   9 drive shaft according to claim 1, characterized in that the bar (3) of the shaft is provided with cooling fins in the region of the condensation zone (120).   Transmission shaft according to claim 9, characterized in that the cooling fins are formed by cooling discs (19) which are force fitted on the outer periphery of the shaft bar or by a cooling fin (18) wound on the outer periphery.