WORKING MACHINE AND A METHOD FOR OPERATING A WORKING MACHINE

• US 20120100956A1
• Filed: 05/07/2009
• Published: 04/26/2012
• Est. Priority Date: 05/07/2009
• Status: Active Grant

• Current Assignee: Volvo Construction Equipment AB (Volvo AB)
• Original Assignee: Volvo Construction Equipment AB (Volvo AB)
• Inventors: Mattsson, Per, Nordstrand, Andreas, Mäki, Rikard
• Granted Patent: US 8,808,136 B2
• Time in Patent Office: Days
• US Class Current: 477/3
• CPC Class Codes: B60K 6/36 characterised by the transmission gearings
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/543 the transmission being a continuously variable transmission
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/103 of fluid type
• CPC Class Codes: B60W 10/24 including control of energy storage means
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: B60W 30/1882 characterised by the working point of the engine, e.g. by using engine output chart
• CPC Class Codes: B60Y 2200/415 Wheel loaders
• CPC Class Codes: B60Y 2300/785 Geared neutral
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements

Abstract

A working machine includes a prime mover for supplying torque to the driving wheels of the working machine, and a transmission line arranged between the prime mover and the driving wheels for transmitting torque from the prime mover to the driving wheels. The transmission line includes a gearbox arranged between the prime mover and the wheels, and the working machine further includes at least one hydraulic machine in a hydraulic system for moving an implement arranged on the working machine and/or steering the working machine, and an electric machine for driving or braking the driving wheels and/or for driving or braking the at least one hydraulic machine. The electric machine is arranged in parallel with the prime mover with respect to the transmission line and is mechanically connected to the transmission line between the prime mover and the gearbox. The gearbox is a continuously variable transmission having a variator unit, and the gearbox has an operation mode where the rotation speed of the output shaft of the gearbox is zero or close to zero independently of the rotation speed of the input shaft of the gearbox at the same time as torque can be transmitted from the input shaft to the output shaft.

Claims

1-19. -19. (canceled)

20. A working machine comprising a prime mover for supplying torque to the driving wheels of the working machine, and a transmission line arranged between the prime mover and the driving wheels for transmitting torque from the prime mover to the driving wheels, the transmission line comprising a gearbox arranged between the prime mover and the wheels, the working machine further comprising at least one hydraulic machine in a hydraulic system for moving an implement arranged on the working machine and/or steering the working machine, and an electric machine for driving or braking the driving wheels and/or for driving or braking the at least one hydraulic machine, the electric machine being arranged in parallel with the prime mover with respect to the transmission line and being mechanically connected to the transmission line between the prime mover and the gearbox, wherein the gearbox is a continuously variable transmission having a variator unit, and the gearbox has an operation mode where the rotation speed of the output shaft of the gearbox is zero or close to zero independently of the rotation speed of the input shaft of the gearbox at the same time as torque can be transmitted from the input shaft to the output shaft.

21. A working machine according to claim 20, wherein the variator unit is a hydraulic variator.

22. A working machine according to claim 20, wherein the gearbox comprises a planetary gear wheel unit enabling the power transmitted by the gearbox to be split between the variator unit and the planetary gear wheel unit.

23. A working machine according to claim 20, wherein the transmission line comprises a transmission component for engagement and disengagement of the prime mover relative to the driving wheels.

24. A working machine according to claim 23, wherein the transmission component is arranged between the prime mover and the electric machine.

25. A working machine according to claim 23, wherein the transmission component is a mechanical clutch.

26. A working machine according to claim 20, wherein the working machine comprises an electric energy storage means.

27. A working machine according to claim 26, wherein the electric energy storage means is arranged to provide energy to the electric machine when the electric machine functions as an electric motor and to store electric energy when the electric machine functions as a generator.

28. A working machine according to claim 20, wherein the at least one hydraulic machine is mechanically connected to the transmission line to enable the hydraulic machine to be driven as a pump by the prime mover and/or to enable the hydraulic machine to transmit energy to the transmission line.

29. A working machine according to claim 20, wherein the at least one hydraulic machine is mechanically connected to the transmission line to enable the hydraulic machine to be driven as a pump by the electric machine and/or to enable the electric machine to be driven as a generator by the hydraulic machine.

30. A working machine according to claim 20, wherein the working machine comprises a further electric machine, and the at least one hydraulic machine is mechanically connected to the further electric machine to enable the hydraulic machine to be driven as a pump by the further electric machine and/or to enable the further electric machine to be driven as a generator by the hydraulic machine.

31. A working machine according to claim 26, wherein the working machine comprises a further electric machine, and the at least one hydraulic machine is mechanically connected to the further electric machine to enable the hydraulic machine to be driven as a pump by the further electric machine and/or to enable the further electric machine to be driven as a generator by the hydraulic machine, and wherein the electric energy storage means is arranged to provide energy to the further electric machine when the electric machine functions as an electric motor and to store electric energy when the further electric machine functions as a generator.

32. A working machine according to claim 20, wherein the working machine is a wheel loader.

33. A method for operating a working machine having a prime mover for supplying torque to the driving wheels of the working machine, and a transmission line arranged between the prime mover and the driving wheels for transmitting torque from the prime mover to the driving wheels, the transmission line comprising a gearbox arranged between the prime mover and the wheels, the working machine further comprising at least one hydraulic machine in a hydraulic system for moving an implement arranged on the working machine and/or steering the working machine, and an electric machine for driving or braking the driving wheels and/or for driving or braking the at least one hydraulic machine, the electric machine being arranged in parallel with the prime mover with respect to the transmission line and being mechanically connected to the transmission line between the prime mover and the gearbox, wherein the method comprises

controlling the gear ratio of the gearbox to enable the electric machine to work at a substantially constant rotation speed throughout a predetermined continuous speed interval of the output shaft of the gearbox for a given value of the power level of the electric machine.

34. A method according to claim 33, wherein the method comprises recovering energy from the hydraulic system by braking the hydraulic machine with the electric machine.

35. A method according to claim 33, wherein the method comprises controlling the braking torque of the electric machine so as to divide the recuperated energy into a first part which is stored in an electric energy storage means connected to the electric machine and into a second part which is transmitted to the transmission line.

36. A method according to claim 33, wherein the method comprises controlling the gearbox to an operation mode where the rotation speed of the output shaft of the gearbox is zero or close to zero independently of the rotation speed of the input shaft of the gearbox at the same time as torque can be transmitted from the input shaft to the output shaft.

37. A computer comprising a computer program for performing the steps of claim 33.

38. A non-volatile computer readable medium comprising a computer program for performing the steps of claim 33.