Wheel drive assembly for a hydrostatic traction drive and hydrostatic traction drive

Patent metadata

Field	Value
Publication number	US-11434994-B2
Application number	US-201916457106-A
Country	US
Kind code	B2
Filing date	Jun 28, 2019
Priority date	Jun 29, 2018
Publication date	Sep 6, 2022
Grant date	Sep 6, 2022

Abstract

In a hydraulic motor and a hydrostatic traction drive with such a hydraulic motor, the regulating of the displacement of the hydraulic motor is done via a pilot-operated pressure regulator. The feedforward controller calculates an estimated motor displacement and relays this to the pressure regulator.

First claim

The invention claimed is:

1. A wheel drive assembly for a hydrostatic traction drive comprising:
a hydraulic motor comprising an electrical adjusting unit configured to adjust a motor displacement of the hydraulic motor to achieve a continuous relation between a motor drive current and the motor displacement; and
an electronic control unit comprising:
a pressure regulator configured to regulate the motor displacement in dependence on an actual pressure supplied to the hydraulic motor and a setpoint pressure of the hydraulic motor; and
a feedforward controller associated with the pressure regulator and configured to preset a preset motor displacement,

wherein the preset motor displacement is a calculated motor displacement calculated based on a model via the feedforward controller based on the setpoint pressure, a motor rotational speed, a pump rotational speed, and one of a pump delivery volume and a pump swivel angle.

2. The wheel drive assembly according to claim 1 , wherein the pressure regulator is nonlinear.

3. The wheel drive assembly according to claim 1 , wherein at least one of the pressure regulator and the feedforward controller have, as an input variable, a rotational speed limit for the hydraulic motor.

4. A hydrostatic traction drive comprising:
a wheel drive assembly comprising:
a hydraulic motor comprising an electrical adjusting unit configured to adjust a motor displacement of the hydraulic motor to achieve a continuous relation between a motor drive current and the motor displacement; and
an electronic control unit comprising:
a pressure regulator configured to regulate the motor displacement in dependence on an actual pressure and a setpoint pressure; and
a feedforward controller associated with the pressure regulator and configured to preset a preset motor displacement; and

an axial piston pump comprising an adjusting unit configured to adjust a pump delivery volume of the axial piston pump,
wherein the preset motor displacement is a calculated motor displacement calculated based on a model via the feedforward controller based on the setpoint pressure, a motor rotational speed, a pump rotational speed, and one of the pump delivery volume and a pump swivel angle.

5. The hydrostatic traction drive according to claim 4 ,
wherein the pump swivel angle is a calculated pump swivel angle, which is calculated on the basis of a model with the aid of a volume flow balance.

6. The hydrostatic traction drive according to claim 4 , wherein the pump swivel angle is a calculated pump swivel angle, which is calculated on the basis of a model in dependence on a leakage under actual pressure, on the motor rotational speed, and on the pump rotational speed and on the motor drive current.

7. The hydrostatic traction drive according to claim 6 , wherein the leakage under actual pressure is a calculated leakage under actual pressure, which is calculated on the basis of a model in dependence on the actual pressure.

8. The hydrostatic traction drive according to claim 4 , wherein the setpoint pressure is determined based on a model in dependence on at least one of: the pump rotational speed, the motor rotational speed, a control element to relay a driver's wish, a forward-neutral-reverse unit, an inching pedal, and a limit load regulator.

9. The hydrostatic traction drive according to claim 4 , wherein at least one of the pressure regulator and the feedforward controller has, as an input variable, a rotational speed limit of the axial piston pump.

10. The hydrostatic traction drive according to claim 4 , wherein the adjusting unit of the axial piston pump comprises an actuating cylinder having a first actuating pressure chamber in which a first actuating pressure is set via a first pressure reducing valve, the first actuating pressure being dependent on a preselected first current strength at a first magnet of the first pressure reducing valve.

Assignees

• Bosch Gmbh Robert

Inventors

• Herrmann Ronny
• Mueller Matthias
• Mumcu Peer

Classifications

• F16H2039/005

  comprising arrangements or layout to change the capacity of the motor or pump by moving the hydraulic chamber of the motor or pump · CPC title

• F16H61/431

  Pump capacity control by electro-hydraulic control means, e.g. using solenoid valves · CPC title

• F16H61/421 Primary

  Motor capacity control by electro-hydraulic control means, e.g. using solenoid valves · CPC title

• F16H61/4017

  Control of high pressure, e.g. avoiding excess pressure by a relief valve · CPC title

• F16H61/0025

  Supply of control fluid; Pumps therefor · CPC title