Method For Controlling a Hydraulic Cylinder in a Work Machine

• US 20080295504A1
• Filed: 01/16/2007
• Published: 12/04/2008
• Est. Priority Date: 01/16/2006
• Status: Active Grant

• Current Assignee: Volvo Construction Equipment AB (Volvo AB)
• Original Assignee: Volvo Construction Equipment AB (Volvo AB)
• Inventors: Palo, Markku, Vigholm, Bo
• Granted Patent: US 8,407,993 B2
• Time in Patent Office: Days
• US Class Current: 60/327
• CPC Class Codes: E02F 9/2095 Control of electric, electro-mechanical or mechanical equipment not otherwise provided for, e.g. ventilators, electro-driven fans control of hydraulic driven equipment E02F9/22
• CPC Class Codes: E02F 9/2207 for reducing or compensating oscillations
• CPC Class Codes: E02F 9/2217 with energy recovery arrangements, e.g. using accumulators, flywheels
• CPC Class Codes: E02F 9/2289 Closed circuit
• CPC Class Codes: E02F 9/2292 Systems with two or more pumps
• CPC Class Codes: E02F 9/2296 Systems with a variable displacement pump
• CPC Class Codes: E02F 9/265 with follow-up actions (e.g. control signals sent to actuate the work tool)
• CPC Class Codes: F03C 1/00 Reciprocating-piston liquid engines
• CPC Class Codes: F04B 17/03 driven by electric motors
• CPC Class Codes: F15B 11/0406 during starting or stopping F15B11/048 takes precedence
• CPC Class Codes: F15B 21/14 Energy-recuperation means
• CPC Class Codes: F15B 2211/20515 Electric motor
• CPC Class Codes: F15B 2211/20561 reversible
• CPC Class Codes: F15B 2211/20569 capable of working as pump and motor
• CPC Class Codes: F15B 2211/27 Directional control by means of the pressure source
• CPC Class Codes: F15B 2211/30515 Load holding valves
• CPC Class Codes: F15B 2211/3057 having two valves, one for each port of a double-acting output member
• CPC Class Codes: F15B 2211/50518 using pressure relief valves
• CPC Class Codes: F15B 2211/6313 the pressure being a load pressure
• CPC Class Codes: F15B 2211/6336 representing a state of the output member, e.g. position, speed or acceleration
• CPC Class Codes: F15B 2211/7053 : Double-acting output members
• CPC Class Codes: F15B 2211/851 : during starting
• CPC Class Codes: F15B 2211/88 : Control measures for saving energy
• CPC Class Codes: Y10T 137/8593 : Systems

Abstract

A method is provided for controlling a hydraulic cylinder in a work machine, which hydraulic cylinder is arranged to move an implement in relation to a part of a vehicle, with the hydraulic cylinder being controlled by a hydraulic machine. The method includes the steps of detecting initiation of a movement of the implement that is such that the piston of the hydraulic cylinder is moved in a first direction, of driving the hydraulic machine in a first rotational direction, prior to the movement of the implement taking place, so that a line from the hydraulic machine is pressurized, which line is arranged to connect the hydraulic machine to the side of the cylinder toward which the piston will be moved during the movement of the implement.

Claims

1. A method for controlling a hydraulic cylinder in a work machine, which hydraulic cylinder is arranged to move an implement in relation to a part of a vehicle, with the hydraulic cylinder being controlled by a hydraulic machine, comprising detecting initiation of a movement of the implement that is such that a piston in the hydraulic cylinder is moved in a first direction, driving the hydraulic machine in a first rotational direction, prior to the movement of the implement taking place, so that a line from the hydraulic machine is pressurized, which line is arranged to connect the hydraulic machine to the side of the cylinder toward which the piston will be moved during the movement of the implement.

2. The method as claimed in claim 1, comprising allowing the hydraulic machine to rotate in a second rotational direction, opposite to the first rotational direction, after the pressurizing, whereby movement of the implement can commence and a flow of hydraulic fluid from the hydraulic cylinder drives the hydraulic machine in a second rotational direction.

3. The method as claimed in claim 1, wherein a controllable arrangement for opening and closing a flow path between the hydraulic machine and the hydraulic cylinder is arranged on the line from the hydraulic machine, comprising keeping the controllable arrangement closed so that it does not allow flow in the direction from the hydraulic cylinder to the hydraulic machine after detection of the initiation of the movement of the implement, and pressurizing a line between the hydraulic cylinder and the controllable arrangement.

4. The method as claimed in claim 3, comprising opening the controllable arrangement after the pressurizing, in order to allow the hydraulic machine to rotate in a second rotational direction, opposite to the first rotational direction, whereupon the movement can commence and a flow of hydraulic fluid from the hydraulic cylinder drives the hydraulic machine in the second rotational direction.

5. The method as claimed in claim 1, comprising driving the hydraulic machine in the first rotational direction, prior to the movement of the implement taking place, so that a side of the hydraulic machine is pressurized via the line from the hydraulic machine.

6. The method as claimed in claim 1, comprising of driving the hydraulic machine in the first rotational direction, prior to the movement of the implement taking place, so that a piston side of the hydraulic machine is pressurized via the line from the hydraulic machine.

7. The method as claimed in claim 1, comprising detecting initiation of the movement of the implement via an input from an operator of the vehicle.

8. The method as claimed in claim 1, comprising detecting an operating parameter that is indicative of pressurizing of the line from the hydraulic machine, comparing the detected value with a limit value and terminating the pressurizing if the detected value exceeds the limit value.

9. The method as claimed in claim 8, comprising detecting an operating parameter that is indicative of a position of the piston in the hydraulic cylinder.

10. The method as claimed in claim 1, comprising driving the hydraulic machine through a predetermined angle in the first rotational direction.

11. The method as claimed in claim 1, wherein the implement is subjected to a load.

12. The method as claimed in claim 1, wherein the movement of the implement is a lowering movement.

13. The method as claimed in claim 1, wherein the line from the hydraulic machine is arranged to connect the hydraulic machine to the piston side of the hydraulic cylinder.

14. The method as claimed in claim 1, wherein the movement of the implement is a lifting movement.

15. The method as claimed in claim 1, wherein the line from the hydraulic machine is arranged to connect the hydraulic machine to the piston-rod side of the hydraulic cylinder.