Seven-gear gearbox for a motorcar double clutch transmission

• US 7,562,598 B2
• Filed: 03/05/2007
• Issued: 07/21/2009
• Est. Priority Date: 04/04/2005
• Status: Active Grant

• Current Assignee: Oerlikon Graziano SPA (OC Oerlikon Corporation AG)
• Original Assignee: Graziano Trasmissioni SpA (OC Oerlikon Corporation AG)
• Inventors: Falzoni, Gianluigi
• Primary Examiner(s): Wright; Dirk
• Application Number:
  US11/682,060
• Publication Number:
  US 20070144286A1
• Time in Patent Office: 869 Days
• Field of Search: None
• US Class Current: 74/331
• CPC Class Codes: F16H 2003/0931 each countershaft having an output gear meshing with a single common gear on the output shaft
• CPC Class Codes: F16H 2200/0056 the gear ratios comprising seven forward speeds
• CPC Class Codes: F16H 3/006 power being selectively transmitted by either one of the parallel flow paths
• CPC Class Codes: Y10T 74/19233 Plurality of counter shafts

Abstract

The gearbox comprises: a first inner input shaft (10) which carries driving gearwheels (21, 23, 27) associated to the odd gears (I, III, V, VII) and fast for rotation therewith; a second outer input shaft (12) which is coaxial with the first and carries driving gearwheels (22, 24) associated to the even gears (II, IV, VI) and to the reverse gear (R) and fast for rotation therewith; and first and second output shafts (14, 16) carrying idle driven gearwheels (31-38). A first driving gearwheel (21) meshes only with the driven gearwheel (31) of first gear (I); a second driving gearwheel (23) meshes both with the driven gearwheel (33) of third gear (III) and with the driven gearwheel (35) of fifth gear (V); a third driving gearwheel (27) meshes only with the driven gearwheel (37) of seventh gear (VII); a fourth driving gearwheel (24) meshes both with the driven gearwheel (34) of fourth gear (IV) and with the driven gearwheel (36) of sixth gear (VI); and a fifth driving gearwheel (22) meshes with the driven gearwheel (32) of second gear (II) and, via this latter, with the driven gearwheel (38) of reverse gear (R).

Claims

1. Seven-gear gearbox for a motorcar double clutch transmission, comprising:

a gear case;

a first inner input shaft (10) and a second outer input shaft (12) arranged coaxial to the first, said first and second input shafts (10, 12) being supported on the gear case (52);

first and second output shafts (14, 16);

a first group of driving gearwheels (21, 23, 27) carried by the first input shaft (10) so as to-be drivingly connected for rotation therewith, said first group of driving gearwheels being associated to a first gear (I), to a third gear (III), to a fifth gear (V) and to a seventh gear (VII);

a second group of driving gearwheels (22, 24) carried by the second input shaft (12) so as to be drivingly connected for rotation therewith, said second group of driving gearwheels being associated to a second gear (II), to a fourth gear (IV), to a sixth gear (VI) and to a reverse gear (R);

a first group of driven gearwheels (32, 35, 36, 37) idly mounted on the first output shaft (14);

a second group of driven gearwheels (31, 33, 34, 38) idly mounted on the second output shaft (16); and

a first end support (54), a second end support (56) and a third intermediate support (58, 60) arranged to support the first and second input shafts (10, 12) on the gear case (52), wherein the first end support comprises a bearing (54) fitted between the gear case (52) and an end portion of the first input shaft (10) opposite a first side of the gearbox, wherein the second end support comprises a bearing (56) fitted between the gear case (52) and a portion of the second input shaft (12) facing the first side of the gearbox, and wherein the third intermediate support comprises a first bearing (58) radially interposed between the first and second input shafts (10, 12) and a second bearing (60) fitted between the second input shaft (12) and the gear case (52) so as to be axially aligned or superimposed with the first bearing (58).

2. The gearbox of claim 1, wherein the third intermediate support (58, 60) is placed essentially equally spaced from the first and second end supports (54, 56, 57).

3. The gearbox of claim 1, wherein the first and second end supports comprise each a ball bearing (54, 56) or a tapered roller bearing.

4. The gearbox of claim 1, wherein the bearings (58, 60) forming the third intermediate support are ball bearings or roller bearings.

5. The gearbox of claim 1, further comprising a roller cage (57) radially interposed between the first and second input shafts (10, 12) in axially aligned or superimposed arrangement relative to the bearing (56) of the second end support.

6. The gearbox of claim 1, wherein the first and second output shafts (14, 16) are supported on the gear case (52) each by means of a pair of end supports (64, 66, 70, 72).

7. The gearbox of claim 6, wherein the end supports (64, 66, 70, 72) of the first and second output shafts (14, 16) are axially aligned or superimposed each with a respective end support (54, 56) of the first and second input shafts (10, 12).

8. The gearbox of claim 6, wherein the end supports (64, 66, 70, 72) of the first and second output shafts (14, 16) are tapered roller bearings.

9. The gearbox of claim 6, wherein the first and second output shafts (14, 16) are also supported on the gear case (52) by means of a third intermediate support (68, 74).

10. The gearbox of claim 9, wherein the third intermediate support (68, 74) of the first and second output shafts (14, 16) is axially aligned or superimposed with the third intermediate support of the first and second input shafts (10, 12).

11. The gearbox of claim 1, wherein

the first group of driving gearwheels includes a first driving gearwheel (21) associated to the first gear (I), a second driving gearwheel (23) associated both to the third gear (III) and to the fifth gear (V), and a third driving gearwheel (27) associated to the seventh gear (VII);

the second group of driving gearwheels includes a fourth driving gearwheel (22) associated both to the second gear (II) and to the reverse gear (R), and a fifth driving gearwheel (24) associated both to the fourth gear (IV) and to the sixth gear (VI);

the first group of driven gearwheels includes a first driven gearwheel (37) meshing with the third driving gearwheel (27) to realize the seventh gear (VII), a second driven gearwheel (35) meshing with the second driving gearwheel (23) to realize the fifth gear (V), a third driven gearwheel (36) meshing with the fifth driving gearwheel (24) to realize the sixth gear (VI), and a fourth driven gearwheel (32) meshing with the fourth driving gearwheel (22) to realize the second gear (II); and

the second group of driven gearwheels includes a fifth driven gearwheel (31) meshing with the first driving gearwheel (21) to realize the first gear (I), a sixth driven gearwheel (33) meshing with the second driving gearwheel (23) to realize the third gear (III), a seventh driven gearwheel (34) meshing with the fifth driving gearwheel (24) to realize the fourth gear (IV), and an eighth driven gearwheel (38) arranged to be driven to rotate by the fourth driving gearwheel (22) to realize the reverse gear (R).

12. The gearbox of claim 11, wherein the eighth driven gearwheel (38) meshes with the fourth driven gearwheel (32) in such a manner that upon engagement 6f the reverse gear (R) the driving torque is transmitted from the fourth driving gearwheel (22) to the fourth driven gearwheel (32) and from this one to the eighth driven gearwheel (38).

13. The gearbox of claim 11, further comprising a lay shaft (84) on which are idly mounted first and second intermediate gearwheels of reverse gear (80, 82), fast for rotation with each other, wherein the first intermediate gearwheel (80) permanently meshes with the fourth driving gearwheel (22) and the second intermediate gearwheel (82) permanently meshes with the eighth driven gearwheel (38).

14. The gearbox of claim 11, further comprising an intermediate gearwheel of reverse gear (86) which is idly mounted on the first output shaft (14), is fast for rotation with the fourth driven gearwheel (32) and permanently meshes with the eighth driven gearwheel (38).

15. The gearbox according of claim 11, further comprising:

a first coupling sleeve (44) of a synchroniser, arranged to couple selectively the first and second driven gearwheels (37, 35) for rotation with the first output shaft (14) to engage the seventh gear (VII) or the fifth gear (V), respectively;

a second coupling sleeve (46) of a synchroniser, arranged to couple selectively the third and fourth driven gearwheels (36, 32) for rotation with the first output shaft (14) to engage the sixth gear (VI) or the second gear (II), respectively;

a third coupling sleeve (48) of a synchroniser, arranged to couple selectively the fifth and sixth driven gearwheels (31, 33) for rotation with the second output shaft (16) to engage the first gear (I) or the third gear (III), respectively; and

a fourth coupling sleeve (50) of a synchroniser, arranged to couple selectively the seventh and eighth driven gearwheels (34, 38) for rotation with the second output shaft (16) to engage the fourth gear (IV) or the reverse gear (R), respectively.

16. The gearbox of claim 11, wherein the first and third driving gearwheels (21, 27) are arranged adjacently at an and of the first input shaft (10) opposite the first side of the gearbox.