Load-controlled hydraulic supply for an attachment attached to an agricultural tractor

Patent metadata

Field	Value
Publication number	US-12352292-B2
Application number	US-202318348618-A
Country	US
Kind code	B2
Filing date	Jul 7, 2023
Priority date	Jul 18, 2022
Publication date	Jul 8, 2025
Grant date	Jul 8, 2025

Abstract

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.

First claim

What is claimed is:

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.

Assignees

• Deere & Co

Inventors

• Billich Manuel

Classifications

• A01B63/00 Primary

  Lifting or adjusting devices or arrangements for agricultural machines or implements (lifting mechanisms for the cutter-bar of a mower A01D34/24; adjusting devices for the cutter-bar of a mower A01D34/28) · CPC title

• F15B13/025

  Pressure reducing valves · CPC title

• F15B2211/522

  actuated by biasing means, e.g. spring-actuated · CPC title

• B60K2025/026

  by a hydraulic transmission · CPC title

• B60Y2200/221

  Tractors · CPC title