Load-controlled hydraulic supply for an attachment attached to an agricultural tractor
A load-controlled hydraulic supply for an attachment attached to an agricultural tractor includes a hydraulic high-pressure source providing a volume flow in a supply line, a return line leading to a hydraulic reservoir, and a load-indicating line connected to a device for pressure limiting. The volume flow is adjusted based on pressure feedback prevailing at the load-indicating line.
1. A load-controlled hydraulic supply for an attachment attached to an agricultural tractor, comprising:
a variable displacement pump providing a volume flow in a supply line;
a return line leading to a hydraulic reservoir; and
a load-indicating line connected to a pressure-limiting valve;
wherein the volume flow is adjusted based on pressure feedback prevailing at the load-indicating line; and
wherein the valve arrangement comprises a first 2/2-way valve which is pilot-actuated via the externally prevailing load-indicating pressure, wherein the first 2/2-way valve is connected on the inlet side to the variable displacement pump and is prestressed into its open position via an actuating force of a spring element that assists the pilot actuation.
2. The hydraulic supply of claim 1 , wherein the pressure-limiting valve leads into the hydraulic reservoir.
3. The hydraulic supply of claim 1 , wherein the pressure-limiting valve communicates with the load-indicating line via a series-connected flow-limiting element.
4. The hydraulic supply of claim 1 , wherein the pressure-limiting valve is adjustable with regard to the predetermined pressure threshold value.
5. The hydraulic supply of claim 1 , wherein in the supply line there is a pressure-compensated control valve for adjusting the volume flow.
6. The hydraulic supply of claim 1 , further comprising a valve arrangement for variably increasing a load-indicating pressure prevailing externally at the load-indicating line.
7. The hydraulic supply of claim 1 , wherein an enable valve designed as a second 2/2-way valve is connected in series with the first 2/2-way valve, wherein the second 2/2-way valve is pilot-actuated via the externally prevailing load-indicating pressure in such a manner that the second 2/2-way valve takes up an open position when a predetermined pressure threshold value is exceeded.
8. A load-controlled hydraulic supply for an attachment attached to an agricultural tractor, comprising:
a variable displacement pump providing a volume flow in a supply line;
a pressure-compensated control valve for adjusting the volume flow in the supply line;
a return line leading to a hydraulic reservoir;
a pressure-reducing valve located in a load-indicating line; and
a valve arrangement for variably increasing a load-indicating pressure prevailing externally at the load-indicating line;
wherein the volume flow is adjusted based on pressure feedback prevailing at the load-indicating line; and
wherein the valve arrangement comprises a first 2/2-way valve which is pilot-actuated via the externally prevailing load-indicating pressure, wherein the first 2/2-way valve is connected on the inlet side to the variable displacement pump and is prestressed into its open position via an actuating force of a spring element that assists the pilot actuation.
9. The hydraulic supply of claim 8 , wherein the pressure-reducing valve is adjustable with regard to the predetermined pressure threshold value.
10. The hydraulic supply of claim 8 , wherein an enable valve designed as a second 2/2-way valve is connected in series with the first 2/2-way valve, wherein the second 2/2-way valve is pilot-actuated via the externally prevailing load-indicating pressure in such a manner that the second 2/2-way valve takes up an open position when a predetermined pressure threshold value is exceeded.
11. A load-controlled hydraulic supply for an attachment attached to an agricultural tractor, comprising:
a variable displacement pump providing a volume flow in a supply line;
a return line leading to a hydraulic reservoir; and
a load-indicating line connected to a pressure-reducing valve;
wherein the volume flow is adjusted based on pressure feedback prevailing at the load-indicating line; and
wherein the valve arrangement comprises a first 2/2-way valve which is pilot-actuated via the externally prevailing load-indicating pressure, wherein the first 2/2-way valve is connected on the inlet side to the variable displacement pump and is prestressed into its open position via an actuating force of a spring element that assists the pilot actuation.
12. The hydraulic supply of claim 11 , wherein the pressure-reducing valve is adjustable with regard to the predetermined pressure threshold value.
13. The hydraulic supply of claim 11 , wherein in the supply line there is a pressure-compensated control valve for adjusting the volume flow.
14. The hydraulic supply of claim 11 , further comprising a valve arrangement for variably increasing a load-indicating pressure prevailing externally at the load-indicating line.
15. The hydraulic supply of claim 11 , wherein an enable valve designed as a second 2/2-way valve is connected in series with the first 2/2-way valve, wherein the second 2/2-way valve is pilot-actuated via the externally prevailing load-indicating pressure in such a manner that the second 2/2-way valve takes up an open position when a predetermined pressure threshold value is exceeded.