Hydraulic system for linear drives controlled by a displacer element

• US 20060218913A1
• Filed: 01/14/2004
• Published: 10/05/2006
• Est. Priority Date: 01/29/2003
• Status: Active Grant

• Current Assignee: CNH Baumaschinen GmbH (CNH Industrial N.V.)
• Original Assignee: CNH Baumaschinen GmbH (CNH Industrial N.V.)
• Inventors: Ivantysynova, Monika, Weber, Jurgen, Rahmfeld, Robert, Lautner, Erik
• Granted Patent: US 7,543,449 B2
• Time in Patent Office: Days
• US Class Current: 60/464
• CPC Class Codes: F15B 21/082 with different modes
• CPC Class Codes: F15B 7/006 Rotary pump input

Abstract

The invention concerns a hydraulic system for linear drives with a differential cylinder, in particular for mobile machines which through the use of displacement-control of the drives avoids the many and diverse disadvantages of the state of the art and renders possible a precise and energy-efficient control of linear drives with differential cylinders, and which is economical and simple to maintain and which can be well integrated into the total hydraulic system of such machines.

Claims

1. A hydraulic system for positive-displacement-controlled linear drives, in particular for mobile machines with at least one differential cylinder, at least one high pressure circuit, which comprises at least one pump with variable delivery volume and is connected to a low pressure system by at least two releasable non-return-valves,

characterised in that the non-return-valves (7,8) are connected in such a way with an electronic control device (16) that a changeover between a driving in or out of the differential cylinder (2) free from switching surges and a floating position function is possible.

2. A hydraulic system in accordance with claim 1, characterised in that the electronic controller (16) is designed for regulating the pump'"'"'s, delivery volume and direction of delivery.

3. A hydraulic system in accordance with claim 1 or 2, characterised in that for controlling the non-return-valves (7,8) an electro-hydraulic 4/2-way valve (10) is envisaged.

4. A hydraulic system in accordance with claim 1 or 2, characterised in that for controlling the check valves (7,8) two electro-hydraulic 3/2-way valves (28,29) are envisaged.

5. A hydraulic system in accordance with one of preceding claims, characterised in that on at least one connection on the differential cylinder (2) a controllable shutoff valve (11) is envisaged.

6. A hydraulic system in accordance with one of preceding claims, characterised in that the low pressure system (9) is designed as an accumulator filling circuit with an accumulator filling valve (21), a pump (20) with a hydraulic accumulator (22) and a pressure limiting valve (23).

7. A hydraulic system in accordance with one of preceding claims, characterised in that the low pressure system (9) is designed with a pump (20) with hydraulic accumulator (22) and a pressure-limiting valve (23).

8. A hydraulic system in accordance with claim 4, characterised in that the controllable shutoff valve (11) is designed as a seat valve with 3/2-way pilot control.

9. A hydraulic system in accordance with one of preceding claims, characterised in that the controllable shutoff valve (11) is designed as a continuous-valve.

10. A hydraulic system in accordance with one of preceding claims, characterised in that further possibly continuously controllable valves (17,18) are envisaged for the alternative and/or simultaneous control of further differential cylinders (19).

11. A hydraulic system in accordance with one of preceding claims, characterised in that on the high pressure circuit connections (25, 26) for a passive oscillation damping system are envisaged.

12. A hydraulic system in accordance with one of preceding claims, characterised in that the electronic controller (16), the controllable valves (10, 11) and possibly further existing hydraulic components with the variable displacement pump (3) are designed as an integrated component.

13. A hydraulic system in accordance with one of preceding claims, characterised in that sensors (12,13) for recording the system conditions, in particular the differential cylinder position and the hydraulic pressures are envisaged.

14. A hydraulic system in accordance with claim 13, characterised in that an electronic controller (14) for regulating the controllable system components in dependence upon the measured system state and user inputs is envisaged.

15. A mobile machine with at least one hydraulic system in accordance with one of the claims 1 to 14.

16. A mobile machine in accordance with claim 15 characterised in that several high-pressure circuits with a common low-pressure circuit are envisaged.