Method and transmission arrangement for changing gears

• US 7,983,825 B2
• Filed: 10/27/2006
• Issued: 07/19/2011
• Est. Priority Date: 10/27/2005
• Status: Active Grant

• Current Assignee: Brueninghaus Hydromatik GmbH (Robert Bosch GmbH)
• Original Assignee: Brueninghaus Hydromatik GmbH (Robert Bosch GmbH)
• Inventors: Vogl, Karl-Heinz, Dschida, Peter, Frasch, Michael
• Primary Examiner(s): Trammell; James P
• Application Number:
  US12/066,570
• Publication Number:
  US 20080208421A1
• Time in Patent Office: 1,726 Days
• Field of Search: 701/54, 747/331, 747/311, 477/52, 477/68, 604/34, 604/44, 604/68, 604/94
• US Class Current: 701/54
• CPC Class Codes: F16H 2306/48 Synchronising of new gear
• CPC Class Codes: F16H 47/02 the fluid gearing being of the volumetric type
• CPC Class Codes: F16H 61/0403 Synchronisation before shifting
• CPC Class Codes: F16H 61/421 Motor capacity control by electro-hydraulic control means, e.g. using solenoid valves
• CPC Class Codes: F16H 61/423 Motor capacity control by fluid pressure control means
• CPC Class Codes: F16H 61/431 Pump capacity control by electro-hydraulic control means, e.g. using solenoid valves
• CPC Class Codes: F16H 61/433 Pump capacity control by fluid pressure control means
• CPC Class Codes: F16H 61/46 Automatic regulation in accordance with output requirements
• CPC Class Codes: F16H 61/47 for achieving a target output speed

Abstract

The invention concerns a method and a transmission arrangement for changing gears in a transmission with a hydrostatic transmission and a manual gearbox (4) connected downstream from it. First the output torque of a hydrostatic motor (9) is reduced. After the reduction of the output torque of the hydrostatic motor (9), an engaged gear (12, 13) of the manual gearbox (4) which is connected downstream is disengaged. An output rotational speed of the hydrostatic motor (9) corresponding to the gear (13, 12) to be engaged is determined. The gear ratio of the hydrostatic transmission is then adjusted, so that the output rotational speed of the hydrostatic motor (9) is higher than the determined corresponding output rotational speed. After this increased output rotational speed is reached, the gear (13, 12) to be engaged is engaged.

Claims

1. A method of changing first and second gears in a transmission with a hydrostatic transmission and a manual gearbox connected downstream therefrom, a synchronizer being arranged in said downstream manual gear box, comprising:

reducing an output torque of a hydrostatic motor and that of a transmission input shaft which is connected to the hydrostatic motor,

disengaging the first said engaged gear of the manual gearbox which is connected downstream,

determining a rotational speed of the hydrostatic motor and that of the transmission input shaft which is connected to the hydrostatic motor corresponding to the gear to be engaged,

adjusting the gear ratio of the hydrostatic transmission, so that the rotational speed of the hydrostatic motor and of the transmission input shaft which is connected to the hydrostatic motor is higher than the determined corresponding rotational speed, irrespective of the direction of the gear change, and

engaging the second said gear to be engaged;

said steps of determining the rotational speed of the hydrostatic motor and of the transmission input shaft, and of adjusting the gear ratio of the hydrostatic transmission being implemented after the disengagement of said first gear and prior to the engagement of said second gear.

2. The method according to claim 1, wherein to reduce the output torque of the hydrostatic motor, its displacement volume is adjusted to a minimum value.

3. The method according to claim 1, wherein to adjust the output torque of the hydrostatic motor and to disengage and engage the gears, electrical signals are output by an electronic control unit.

4. The method according to claim 1, wherein the rotational speed corresponding to the gear to be engaged is determined by an electronic control unit.

5. The method according to claim 4, wherein at least one rotational speed signal about the output rotational speed of the downstream manual gearbox is fed to the electronic control unit.

6. The method according to claim 1, wherein to adjust the rotational speed of the hydrostatic motor to a rotational speed which is above the determined output rotational speed, the displacement volume of the hydrostatic motor is adjusted.

7. The method according to claim 1, wherein to adjust the rotational speed of the hydrostatic motor to a rotational speed which is above the determined rotational speed, a displacement volume of a hydrostatic hydraulic pump unit of the hydrostatic transmission is adjusted.

8. The method according to claim 6, wherein the hydrostatic motor and/or the hydraulic pump unit is adjusted during a positioning movement of an actuating piston to change gears.