Claims
- 1. A valve system for the hydraulic work system of a work vehicle, comprising:
an elevating drive system for raising and lowering a load, the elevating drive system including a control valve, a hydraulic cylinder and a hydraulic line extending between the control valve and the hydraulic cylinder; a tilting drive system having a hydraulic cylinder and a control valve, with admission and discharge lines in flow communication with the tilting drive system control valve; and a check valve located in the hydraulic line extending between the elevating drive system control valve and hydraulic cylinder, the check valve including a control surface that acts in a direction of an opening position, which control surface is pressurizable by a load pressure of the elevating drive system, and a control pressure chamber that acts in the direction of a closing position, which control pressure chamber is pressurizable by the load pressure of the elevating drive system and is in flow communication with a reservoir when the elevating drive system control valve is actuated to a descent position.
- 2. The valve system as claimed in claim 1, including flow regulators having open and closed positions located in the tilting drive system admission and discharge lines, wherein the flow regulators are pressurized toward the closed position by a pressure upstream of a throttle point of the tilting drive system control valve and toward an open position by a pressure downstream of the throttle point of the tilting drive system control valve and a spring.
- 3. The valve system as claimed in claim 1, wherein the control pressure chamber is in flow communication with a pressure relief valve which is realized in the form of a seat valve and is in flow communication with a reservoir, wherein the relief valve is movable into a closed position by a load pressure of the elevating drive system, and into an open position when the control valve of the elevating drive system is actuated into the descent position in which the control pressure chamber of the check valve is in communication with the reservoir.
- 4. The valve system as claimed in claim 1, wherein the control pressure chamber of the check valve is pressurized by a fixed diaphragm with a load pressure of the elevating drive system.
- 5. The valve system as claimed in claim 3, including a stepper motor generally connected to the control valve of the elevating drive system, wherein the stepper motor is effectively connected with the relief valve and moves the relief valve into the open position when the elevating drive system control valve is actuated into the descent position.
- 6. The valve system as claimed in claim 5, wherein the control valve of the elevating drive system is realized as a longitudinal slide valve with a valve slide, and the stepper motor is connected to a control piston of the elevating drive system control valve by a transmission, wherein the valve slide is mounted non-rotationally but so that it is movable longitudinally in a housing boring and wherein a spring device holds the valve slide in a middle position in a non-actuated status.
- 7. The valve system as claimed in claim 6, wherein the relief valve has a valve body which is effectively connected with the valve slide of the control valve of the elevating drive system by an actuator element.
- 8. The valve system as claimed in claim 1, including a return line extending from the control valve of the elevating drive system to a tank line, with a descent braking valve located in the return line and which descent braking valve is pressurized toward an open position by a spring and the pressure downstream of the throttle point of the elevating drive system control valve and toward a closed position by the pressure upstream of the throttle point of the elevating drive system control valve.
- 9. The valve system as claimed in claim 2, wherein an opening orifice of throttle points in the admission line and in the discharge line exposed by the control valve of the tilting drive system are dimensioned as a function of a ratio of a surface area of a piston and a surface area of a piston rod of the hydraulic cylinder of the tilting drive system.
- 10. The valve system as claimed in claim 1, including an additional check valve located in a delivery line downstream of the control valve of the elevating drive system and upstream of the control valve of the tilting drive system, the additional check valve openable toward the control valve of the tilting drive system.
- 11. The valve system as claimed in claim 2, including at least one additional drive system which includes a double-action hydraulic cylinder and which is actuated by an additional control valve, the additional control valve connected to a delivery line downstream of the control valve of the tilting drive system, wherein downstream of an admission-side throttle orifice of the control valves, respective load pressure lines are connected and the load pressure signal lines are connected by a system of shuttle valves formed from a plurality of shuttle valves to a common load pressure signal line that is connected to a pressure balance.
- 12. The valve system as claimed in claim 11, wherein the pressure balance connects the delivery line to the tank line and has a closed position and an open position, and wherein the pressure balance is pressurized toward the open position by pump pressure and toward the closed position by the highest load pressure of the actuated users present in the common load pressure line and by a spring.
- 13. The valve system as claimed in claim 11, wherein an actuator device of the control valve of the tilting drive system and of the control valve of the additional drive system is configured as a double-action proportional magnet, whereby the tilting drive system and additional drive system control valves are centered in a middle position by a spring device.
- 14. The valve system as claimed in claim 11, wherein at least one of the elevating drive system control valve, the tilting drive system control valve, the additional drive system control valve, the check valves, a relief valve, the flow regulators, the shuttle valves and the pressure balance are located in a control block that has a laminated construction including a plurality of segmental plates that are laminated to one another and have recesses, the contours and orientation of which in relation to one another form hydraulic channels and housing borings as well as control pressure chambers.
- 15. The valve system as claimed in claim 14, wherein on one surface of a segmental plate that forms one lateral surface of the control block are located a connection socket for a pump connection and a connection socket for a tank connection with connection sockets for user connections and electrical actuator devices of the control valves located on an opposite lateral surface of the control block which is formed by a surface of an additional segmental plate.
- 16. The valve system as claimed in claim 15, wherein the connection sockets for the pump connection and the tank connection as well as the connection sockets for the user connections are soldered into the control block.
- 17. The valve system as claimed in claim 14, wherein the actuator devices of the control valves are fastened in housing components that are soldered into the control block.
- 18. A valve system for the hydraulic work system of a work vehicle, comprising:
an elevating drive system for raising and lowering a load, the elevating drive system including a control valve, a hydraulic cylinder and a hydraulic line extending between the control valve and the hydraulic cylinder; a tilting drive system having a hydraulic cylinder and a control valve, with admission and discharge lines in flow communication with the tilting drive system control valve; and flow regulators having open and closed positions located in the tilting drive system admission and discharge lines, wherein the flow regulators are pressurized toward the closed position by a pressure upstream of a throttle point of the tilting drive system control valve and toward an open position by a pressure downstream of the throttle point of the tilting drive system control valve and a spring.
- 19. The valve system as claimed in claim 1, wherein the elevating drive system includes a single-action hydraulic cylinder and the tilting drive system includes a double-action hydraulic cylinder.
- 20. The valve system as claimed in claim 6, wherein the transmission is a spindle-nut transmission.
Priority Claims (1)
Number |
Date |
Country |
Kind |
198 04 398.8 |
Feb 1998 |
DE |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 09/229,423, filed Jan. 13, 1999, entitled “Control Valve System for the Hydraulic Work System of a Work Vehicle.”
Continuations (1)
|
Number |
Date |
Country |
Parent |
09229423 |
Jan 1999 |
US |
Child |
09794966 |
Feb 2001 |
US |