FR2881804A1 - Double clutch transmission for motor vehicle, has one input shaft carried by another input shaft using connection system that includes ball bearings integrated to shafts and having inner ring mounted on latter shaft and outer ring - Google Patents

Abstract

The transmission has two concentric input shafts (10, 20), each cooperating with a clutch, where the shaft (20) is carried by the shaft (10) using a connection system. The connection system includes ball bearings (11) integrated to the shafts. The bearings include an inner ring (11A) mounted on the shaft (10) and an outer ring (11B) having a groove for receiving a spring retaining ring (63) integrated to the shaft (20). An independent claim is also included for a motor vehicle including a transmission.

Description

TECHNICAL FIELD TO WHICH THE INVENTION REFERS

  The present invention generally relates to dual clutch transmissions.

  It relates more particularly to a gearbox comprising two concentric primary shafts each cooperating with a clutch, the second main shaft being carried by the first primary shaft by means of a bearing connection system.

  It also relates to a motor vehicle comprising such a gearbox.

BACKGROUND

  Dual clutch systems are generally used to prevent any interruption of traction during shifting. These clutches are secured in rotation to concentric primary shafts which directly or indirectly transmit the torque to two secondary shafts, one carrying odd gear gears, and the other bearing gears of even gear ratios.

  A housing provides support for the various elements included in the gearbox.

  Currently, the first primary shaft is supported axially and radially by the housing in favor of a ball bearing secured to the housing. The second primary shaft is supported radially by the housing by means of cylindrical roller bearings and / or needles.

  It is also known to mount the two primary shafts one on the other by means of a bearing connection system comprising needle bearings and / or cylindrical roller bearings.

  Needle bearings or cylindrical roller bearings allow, by their structure, to take the radial forces and not the axial forces exerted between the two primary shafts.

  In order to take up these axial forces, it is therefore necessary to add axial thrust bearings with cylindrical or needle roller bearings, making it possible to stop the second primary shaft axially relative to the first primary shaft and thus to take up the axial forces of the second shaft. primary on the first.

  The necessary addition of the two axial thrust bearings then forces to adjust the mounting the axial clearance of the second primary shaft relative to the first input shaft to ensure the transmission of the axial forces of the second primary shaft to the first.

  OBJECT OF THE INVENTION Compared to the prior art, the present invention provides a double clutch gearbox comprising two primary shafts that overcomes the adjustment of the axial clearance between the two primary shafts.

  More particularly, the invention proposes a gearbox as defined in the introduction in which it is provided that the connecting system of the two primary shafts comprises a ball bearing secured to said primary shafts.

  Thus, according to the invention, thanks to the joining of the ball bearing to the two primary shafts, the axial clearance of the second shaft relative to the first shaft only depends on the axial play of the balls in the inner and outer rings of said bearing and it There is therefore no adjustment of the axial clearance between the two shafts to be performed. In addition, the use of a ball bearing makes it possible to obtain a lower drag torque between the second primary shaft and the first primary shaft.

  According to a first advantageous characteristic of the invention, said ball bearing comprises an inner ring forcibly mounted on the first primary shaft, resting against a shoulder integral therewith.

  According to another advantageous characteristic of the invention, said ball bearing comprises an outer ring provided with a groove which accommodates a circlip secured to the second primary shaft.

  In this way, the axial forces of the second primary shaft are transmitted via the circlip to the ball bearing in both directions and the ball bearing transmits via force mounting these axial forces to said first primary shaft in both directions.

  In addition, advantageously, said circlip secured to the second primary shaft forms an axial stop and then reduces the number of parts necessary for mounting the two primary shafts one on the other including eliminating the addition of two axial stops .

  According to another advantageous characteristic of the invention, there is provided opposite said shoulder of the first primary shaft a circlip mounted in a groove of the first primary shaft so that said inner ring of said ball bearing is sandwiched between said shoulder and the circlips.

  The sandwiching of the inner ring of the ball bearing between the shoulder and the circlip assures the correct positioning of this inner ring on the first primary shaft in case of rotational bending.

  According to another advantageous characteristic of the invention, the connection system of the two primary shafts comprises a needle or cylindrical roller bearing.

  The positioning of this needle bearing on the first primary shaft advantageously allows to control the bending deformations of the two primary shafts and to distribute the forces passing through the ball bearing of the connecting system of the two primary shafts.

  The invention also relates to a motor vehicle comprising a gearbox as mentioned above.

  DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT

  The following description with reference to the attached drawing of an embodiment, given by way of non-limiting example, will make it clear what the invention consists of and how it can be achieved.

  In the accompanying drawing, the single figure is an axial sectional view of a portion of a double-clutch gearbox according to the invention.

  In the single figure, there is shown a gearbox comprising two concentric primary shafts 10,20 each associated with a clutch.

  Each primary shaft has, at one of its ends, splines 13,21 cooperating with an inner bell 41,42 of each clutch.

  The first primary shaft 10 carries 51,53 pinions and has a toothing 52 machined on this first primary shaft 10. These pinions 51,53 and this toothing 52 are intended for odd gear ratios.

  The second primary shaft 20 comprises a sprocket 54 coming from formation with the second primary shaft and a toothing 56 machined on the second primary shaft 20 for even gear ratios.

  The teeth of the pinions 51, 53, 54 and those 52, 52 machined on the said primary shafts 10, 20 are helical. Thus, the forces resulting from the cooperation of these teeth with those of the secondary shafts (not shown) of the gearbox are decomposed into radial and axial forces.

  The two primary shafts 10,20 are mounted in a housing 30 which, for mounting considerations, is in several parts.

  We see in the single figure that a portion 30A of the housing 30 supports the first primary shaft 10 and two other parts 30B, 30C of the housing 30 support the second primary shaft 20. Each of the two primary shafts 10,20 is connected to the 30A, 30B, 30C of the corresponding housing 30 by a bearing connection system.

  In particular, the first primary shaft 10 is connected to the portion 30A of the housing 30 by a ball bearing 31 mounted on the end of said primary shaft 10 opposite that with the grooves 13. Here, the inner ring of the ball bearing 31 is held between the pinion 51 carried by said first primary shaft 10 and a stop circlip 62 mounted in a groove provided in said primary shaft 10.

  In addition, the outer ring of the ball bearing 31 is provided with a groove which accommodates a circlip 61 engaged in a groove provided in the part 30A of the casing 30.

  The ball bearing 31 provides the axial reference of the first primary shaft 10 relative to the housing 30. This axial reference is made in both directions A and B. The ball bearing 31 also realizes a radial reference for the first primary shaft 10. To recover significant axial forces, the ball bearing 31 used can be deep groove.

  The second primary shaft 20 is connected to the portion 30B of the housing 30 by a cylindrical roller bearing 32. This cylindrical roller bearing 32 comprises an outer ring secured to the portion 30B of the housing 30 and an inner ring secured to the second primary shaft 20 The second primary shaft 20 is connected to the portion 30C of the housing 30 by a needle bearing 33.

  The second primary shaft 20 is carried by the first primary shaft 10 by means of a rolling connection system.

  Here, this rolling connection system comprises, starting from the end comprising the splines 13 of the first primary shaft 10 towards the opposite end of this first primary shaft 10, firstly a needle bearing 12 and then, advantageously according to the invention, a ball bearing 11.

  As can be seen in the drawing of the single figure, the ball bearing 11 links the non-splined end of the second primary shaft 20 to the first primary shaft 10.

  The ball bearing 11 comprises an inner ring 11A forcibly mounted on the first primary shaft 10, bearing against a shoulder 10A thereof. The inner ring 11A of the ball bearing 11 is held between the shoulder 10A of the first primary shaft 10 and a stop circlip 64 mounted in a groove provided in said primary shaft 10. Here, the shoulder 10A is made at least in partly by the hub of pinion 53.

  In addition, the ball bearing 11 comprises an outer ring 11B provided with a groove which accommodates a circlip 63 secured to the second primary shaft 20.

  The fastening of the circlip 63 to the second primary shaft 20 is ensured by the engagement of the circlip 63 in a groove provided in the second primary shaft 20.

  A radial slot 22 is provided in the second primary shaft 20 to be able to disengage the circlip 63 from the groove of the second primary shaft 20 and thus disassemble the two primary shafts 10,20.

  Advantageously, the ball bearing 11 carries the axial reference of the second primary shaft 20 on the first primary shaft 10.

  There is provided a first seal 70 between the two primary shafts 10,20 to the right of the ball bearing 11 in the drawing of the single figure.

  A second seal 71 is provided between the second primary shaft 20 and the portion 30B of the housing 30 to the right of the cylindrical roller bearing 32 in the drawing of the single figure.

  The various components of the double-clutch transmission are assembled as follows: Firstly, the needle bearing 33 is mounted in the part 30C of the casing 30. Then, the seal 71 is mounted in the portion 30B of the housing 30. Finally, the cylindrical roller bearing 32 is also mounted in the portion 30B of the housing 30. The outer ring of the cylindrical roller bearing 32 then bears against a shoulder of the portion 30B of the housing 30.

  In parallel, the two ball bearings 11, 31 are mounted by shrinking on the first primary shaft 10. The shoulder 10A of the first primary shaft 10 formed at least in part by the pinion 53 makes it possible to ensure the stop and the good positioning. of the ball bearing 11. Similarly, the shoulder formed by the pinion 51 ensures the stopping and proper positioning of the ball bearing 31.

  Each of the two circlips 62,64 is mounted in the groove of the corresponding first primary shaft 10. Then, the circlip 63 is mounted in the groove of the outer ring 11B of the ball bearing 11. Similarly, the circlip 61 is mounted in the groove of the outer ring of the ball bearing 31.

  Then, the needle bearing 12 is mounted on the first primary shaft 10. The positioning of the needle bearing 12 between the two primary shafts 10, 20 makes it possible to control the bending deformation of the two primary shafts 10, 20. The positioning of this needle bearing 12 also allows to distribute the mechanical forces passing through the ball bearing 11 ensuring the connection between the two primary shafts 10,20.

  Finally, the seal 70 is mounted inside the second primary shaft 20.

  Then the second primary shaft 20 is assembled on the first primary shaft 10. During assembly of the two primary shafts 10,20, the circlip 63 of the outer ring 11B of the ball bearing 11 engages in the groove of the second primary shaft 20.

  The two primary shafts 10,20 then forming a compact assembly, this assembly is mounted in the portion 30A of the casing 30 via the ball bearing 31. When assembling all the two primary shafts 10,20 in the portion 30A of the 30, the circlip 61 of the outer ring of the ball bearing 31 engages in the groove of the portion 30A of the housing 30.

  Finally, the assembly consisting of the portion 30A of the housing 30 and the two primary shafts 10,20 is connected to the parts 30B and 30C of the housing 30 comprising the cylindrical roller bearing 32 and the needle bearing 33 previously mounted. During this connection, the second primary shaft 20 passes through the cylindrical roller bearing 32 and the needle bearing 33. The second primary shaft 20 is then supported radially by the cylindrical roller bearing 32 and the needle bearing 33.

  In operation, the two concentric primary shafts 10, 20 rotate one over the other.

  The axial forces resulting on the second primary shaft 20 are taken up in both directions by the first primary shaft 10 by means of the ball bearing 11 secured to the two primary shafts 10,20.

  Finally, the axial forces resulting on the first primary shaft 10 are taken up in both directions by the portion 30A of the housing 30 carrying the first primary shaft 10, by means of the ball bearing 31 secured to the portion 30A of the housing 30.

  In addition, the radial forces of the second primary shaft 20 on the first primary shaft 10 and vice versa are transmitted by the ball bearing 11 and the needle bearing 12. The ball bearing 31 ensures the recovery of the radial forces of the first primary shaft 10 to the portion 30A of the housing 30. Similarly the cylindrical roller bearing 32 and the needle bearing 33 ensure the recovery of the radial forces of the second primary shaft 20 to the parts 30B and 30C of the housing 30.

  The present invention is not limited to the embodiment described and shown, but the skilled person will be able to make any variant within his mind.

Claims (1)

8 claims   Gearbox comprising two concentric primary shafts (10, 20) each cooperating with a clutch, the second primary shaft (20) being carried by the first primary shaft (10) by means of a rolling connection system, characterized in that the connecting system of the two primary shafts (10, 20) comprises a ball bearing (11) secured to said primary shafts (10, 20).   2. Gearbox according to claim 1, characterized in that said ball bearing (11) comprises an inner ring (11A) forcibly mounted on the first primary shaft (10), bearing against a shoulder (10A) integral with this one.   3. Gearbox according to one of claims 1 or 2, characterized in that said ball bearing (11) comprises an outer ring (11B) provided with a groove which accommodates a circlip (63) secured to the second primary shaft (20).   4. Gearbox according to claim 3, characterized in that the securing of the circlip (63) to the second primary shaft (20) is ensured by the engagement of the circlip (63) in a groove provided in the second primary shaft (20). ).   5. Gearbox according to one of claims 2 to 4, characterized in that it is provided opposite said shoulder of the first primary shaft (10) a circlip (64) mounted in a groove of the first primary shaft ( 10) so that said inner ring (11A) of the ball bearing (11) is sandwiched between said shoulder (10A) and the circlip (64).   Gearbox according to one of Claims 1 to 5, characterized in that the connecting system of the two primary shafts (10, 20) comprises a needle or cylindrical roller bearing (12).   7. Motor vehicle comprising a gearbox according to any one of the preceding claims.