Transmission

• US 10,138,983 B2
• Filed: 04/18/2014
• Issued: 11/27/2018
• Est. Priority Date: 05/01/2013
• Status: Active Grant

• Current Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Original Assignee: Jaguar Land Rover Limited (TATA Motors Limited)
• Inventors: Hose, Markus, Osborn, Russell, Hyde, Fred, Hole, Matt
• Primary Examiner(s): Joyce, William C
• Application Number:
  US14/787,831
• Publication Number:
  US 20160076626A1
• Time in Patent Office: 1,684 Days
• Field of Search: 74330, 74331
• CPC Class Codes: B60K 17/08 of mechanical type
• CPC Class Codes: B60K 17/346 the transfer gear being a differential gear
• CPC Class Codes: F16H 2003/0822 characterised by the arrangement of at least one reverse gear
• 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 2003/0933 with coaxial countershafts
• CPC Class Codes: F16H 2057/02047 Automatic transmissions
• CPC Class Codes: F16H 2057/0216 Intermediate shaft supports, e.g. by using a partition wall
• CPC Class Codes: F16H 2200/006 the gear ratios comprising eight forward speeds
• CPC Class Codes: F16H 2200/0086 the gear ratios comprising two reverse speeds
• CPC Class Codes: F16H 3/006 power being selectively transmitted by either one of the parallel flow paths
• CPC Class Codes: F16H 3/093 with two or more countershafts
• CPC Class Codes: F16H 3/097 the input and output shafts being aligned on the same axis
• CPC Class Codes: F16H 57/021 Shaft support structures, e.g. partition walls, bearing eyes, casing walls or covers with bearings

Abstract

A constant mesh gear transmission has an input shaft (21, 22), two layshafts (31, 35) and an output shaft (23). Gear wheels are selectively connectable to shafts to provide forward and reverse speed ratios. A common central web (39) provides central support bearings for the shafts. The transmission is stiffened, and allows assembly of components from either end to the middle.

Claims

1. A constant mesh gearbox providing a plurality of forward speed ratios, said gearbox comprising a casing defining a plurality of parallel shaft axes having shafts rotatable thereon, and between which gear wheel pairs associated with each speed ratio are arranged to transmit torque, said casing defining a support plane substantially orthogonal to said axes and containing a support bearing for a shaft on each of said axes, said gearbox providing four or more forward speed ratios, the gear wheel pairs associated with odd forward speed ratios being provided on one side of said support plane, and the gear wheel pairs associated with even forward speed ratios being provided on the other side of said support plane, the arrangement of speed ratios being at least partially symmetrical about the support plane and wherein on the one side of said support plane the gear wheels of an input shaft decrease progressively in diameter toward said support plane, and on the other side of said support plane the gear wheels of an input shaft increase progressively in diameter away from said support plane,

said gearbox including two reverse speed ratios, the gear wheel pairs associated with one of said reverse speed ratios being provided on the one side of said support plane, and the gear wheel pairs associated with the other of said reverse speed ratios being provided on the other side of said support plane.

2. A gearbox according to claim 1, comprising an input shaft, an output shaft and two layshafts.

3. A gearbox according to claim 2, comprising two co-axial input shafts.

4. A gearbox according to claim 3, wherein said input shafts are arranged one within the other.

5. A gearbox according to claim 2, wherein said output shaft is coaxial with the input shaft.

6. A gearbox according to claim 2, comprising two layshafts only.

7. A gearbox according to claim 6, wherein said layshafts are engaged with said output shaft via respective gear wheels.

8. A gearbox according to claim 1, wherein said support plane is defined by a transverse web of said casing, said web providing a plurality of bearings, one for each shaft passing through said support plane.

9. A gearbox according to claim 1, including two end support planes having substantially therein respective support bearings for each end of the shafts rotatable in said casing.

10. A gearbox according to claim 9, comprising layshafts and support bearings for the layshafts provided in parallel end support planes.

11. A gearbox according to claim 10, wherein said layshafts are geared together by spur gear wheels inboard of said end support planes.

12. A gearbox according to claim 1, having eight forward speed ratios, six forward speed ratios being defined by gear wheel pairs directly between an input shaft and a first layshaft, and two forward speed ratios being defined by a gear train between an input shaft and the first layshaft via first idlers of the first layshaft and second idlers of a second layshaft.

13. A gearbox according to claim 12, wherein said first idlers comprise first driving and first driven gear wheels connected for rotation in common.

14. A gearbox according to claim 12, wherein said second idlers comprise second driving and second driven gear wheels connected for rotation in common, said second driven gear wheels being immediately adjacent said support plane.

15. A gearbox according to claim 12, wherein said second idlers are connectable to said second layshaft.

16. A gearbox according to claim 1, wherein each speed ratio is individually selectable via movement of a synchromesh coupler.

17. An internal combustion engine having a crankcase coupled to the casing of a gearbox according to claim 1.

18. A vehicle powertrain or a vehicle incorporating a gearbox according to claim 1.

19. A vehicle comprising a gearbox according to claim 1.

20. A constant mesh gearbox providing a plurality of forward speed ratios, said gearbox comprising a casing defining a plurality of parallel shaft axes having shafts rotatable thereon, and between which gear wheel pairs associated with each speed ratio are arranged to transmit torque, said casing further defining a support plane substantially orthogonal to said axes and containing a support bearing for a shaft on each of said axes, said gearbox providing four or more forward speed ratios, the gear wheel pairs associated with odd forward speed ratios being provided on one side of said support plane as a first series of gear wheel pairs, and the gear wheel pairs associated with even forward speed ratios being provided on an opposite side of said support plane as a second series of gear wheel pairs, and wherein on the one side of said support plane the gear wheels of an input shaft belonging to the first series of gear wheel pairs decrease progressively in diameter toward said support plane, and on the opposite side of said support plane the gear wheels of an input shaft belonging to the second series of gear wheel pairs increase progressively in diameter away from said support plane, said gearbox having two reverse speed ratios, gear wheel pairs associated with one of said reverse speed ratios being provided on the one side of said support plane, and gear wheel pairs associated with the other of said reverse speed ratios being provided on the opposite side of said support plane.