Hydraulic system for energy regeneration in a work machine such as a wheel loader

Patent metadata

Field	Value
Publication number	US-9879404-B2
Application number	US-201113324620-A
Country	US
Kind code	B2
Filing date	Dec 13, 2011
Priority date	Dec 13, 2010
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

A hydraulic system is adapted to recover potential and kinetic energy of a work attachment of a work machine. A valve arrangement may configure the hydraulic system in various modes. The hydraulic system may provide suspension and/or actuation for the work attachment. The energy of the work attachment may move a rod of a first cylinder. The rod may pressurize fluid within the first cylinder. The pressurized fluid may flow from the first cylinder through a valve and into an accumulator. The first cylinder may amplify pressure of the fluid. The pressurized fluid in the accumulator may actuate the first cylinder. The movement of the rod of the first cylinder may cause simultaneous actuation of a second cylinder. A controller may monitor pressures and positions of components of the hydraulic system and control the valve arrangement.

First claim

What is claimed is:

1. A method of reusing energy of a work attachment of a work machine, the method comprising:
opening hydraulic fluid flow through a first flow control device, the first flow control device fluidly connected between an accumulator and a head chamber of a first hydraulic cylinder;
compressing the head chamber by moving a piston and rod of the first hydraulic cylinder with the work attachment and thereby charging the accumulator with the hydraulic fluid flow; and
simultaneously actuating a second hydraulic cylinder by opening hydraulic fluid flow through a second flow control device connected between the second hydraulic cylinder and the head chamber of the first hydraulic cylinder;
wherein the first hydraulic cylinder further includes a rod chamber and a third flow control device fluidly connects the head chamber to the rod chamber and thereby amplifies a hydraulic pressure generated within the first hydraulic cylinder and used to charge the accumulator.

2. The method of claim 1 , wherein the moving of the piston and rod is at least partly done by gravity acting on mass of the work attachment.

3. The method of claim 1 , wherein the moving of the piston and rod is at least partly done by decelerating mass of the work attachment.

4. The method of claim 1 , wherein the first hydraulic cylinder, the accumulator, and the first fluid flow control device belong to a suspension system of the work machine.

5. The method of claim 1 , wherein the work machine is a wheel loader and the first hydraulic cylinder is connected to a boom of the work attachment.

6. The method of claim 5 , wherein the first hydraulic cylinder, the accumulator, and the first fluid flow control device belong to a boom suspension system of the wheel loader.

7. The method of claim 5 , wherein the second hydraulic cylinder is connected to the second component that is a bucket linkage of the work attachment.

8. The method of claim 1 , wherein compressing the head chamber by moving the piston and the rod of the first hydraulic cylinder with the work attachment and simultaneously actuating the second hydraulic cylinder by opening the hydraulic fluid flow through the third flow control device extends the second hydraulic cylinder.

9. A hydraulic system for actuating a work attachment of a mobile work machine, the hydraulic system comprising:
a first hydraulic cylinder configured to actuate the work attachment, the first hydraulic cylinder including a piston connected to a rod, the piston positioned between a head chamber and a rod chamber of the first hydraulic cylinder, and the rod extending through the rod chamber;
an accumulator;
a first flow control device fluidly connected between the accumulator and the head chamber of the first hydraulic cylinder, the first flow control device conveying accumulator fluid flow; and
a second flow control device fluidly connected between the head chamber and the rod chamber of the first hydraulic cylinder, the second flow control device conveying head to rod chamber fluid flow;
wherein the accumulator fluid flow from the head chamber of the first hydraulic cylinder charges the accumulator when the work attachment compresses the first hydraulic cylinder and the first flow control device is open;
wherein a hydraulic pressure of the accumulator fluid flow is amplified by opening the second flow control device between the head chamber and the rod chamber of the first hydraulic cylinder; and
wherein net head chamber fluid flow of the head chamber equals a sum of the accumulator fluid flow and the head to rod chamber fluid flow when the hydraulic pressure of the accumulator fluid flow is amplified and charges the accumulator.

10. The hydraulic system of claim 9 , wherein the mobile work machine is a wheel loader and the first hydraulic cylinder is connected to a boom of the work attachment.

11. The hydraulic system of claim 10 , wherein the first hydraulic cylinder, the accumulator, and the first flow control device belong to a suspension system of the wheel loader.

12. The hydraulic system of claim 10 , further comprising a bucket cylinder of the work attachment and a third flow control device connected between the bucket cylinder and the head chamber of the first hydraulic cylinder, wherein simultaneous movement of the first hydraulic cylinder and the bucket cylinder occurs from the work attachment compressing the first hydraulic cylinder.

13. The hydraulic system of claim 9 , wherein a fluid displacement rate of the head chamber is between about 1.1 and 3 times larger than a fluid displacement rate of the rod chamber when the piston is moved.

14. The hydraulic system of claim 9 , further comprising:
a pump;
a valve set including a plurality of valves, the valve set fluidly connected between the head chamber of the first hydraulic cylinder and the pump and also fluidly connected between the rod chamber of the first hydraulic cylinder and the pump, the valve set adapted to direct fluid flow from the pump to the head chamber to extend the first hydraulic cylinder and the valve set adapted to direct the fluid flow from the pump to the rod chamber to retract the first hydraulic cylinder; and
a fluid passage fluidly connected between the head chamber of the first hydraulic cylinder and the hydraulic accumulator, the fluid passage not passing through any of the plurality of valves of the valve set, the fluid passage including the first flow control device connected to the head chamber of the first hydraulic cylinder by a first fluid line of the fluid passage and to the hydraulic accumulator by a second fluid line of the fluid passage.

15. The hydraulic system of claim 14 , further comprising a tank, wherein the valve set is fluidly connected between the head chamber of the first hydraulic cylinder and the tank and also fluidly connected between the rod chamber of the first hydraulic cylinder and the tank.

16. The hydraulic system of claim 9 , wherein the hydraulic system is adapted to capture energy from the work attachment and store the energy in the accumulator and wherein the hydraulic system is adapted to reuse the energy by actuating the work attachment with the rod of the first hydraulic cylinder.

17. The hydraulic system of claim 9 , wherein the hydraulic system is adapted to actuate the work attachment by lifting the work attachment with the rod of the first hydraulic cylinder.

18. The hydraulic system of claim 9 , wherein the second flow control device includes a first valve and a second valve that are open when the second flow control device is open.

19. A method of using a hydraulic system for actuating a work attachment of a mobile work machine, the method comprising:
providing the hydraulic system, the hydraulic system including:
a first hydraulic cylinder configured to actuate the work attachment, the first hydraulic cylinder including a piston connected to a rod, the piston positioned between a head chamber and a rod chamber of the first hydraulic cylinder, and the rod extending through the rod chamber;
an accumulator;
a first flow control device fluidly connected between the accumulator and the head chamber of the first hydraulic cylinder, the first flow control device conveying accumulator fluid flow; and
a second flow control device fluidly connected between the head chamber and the rod chamber of the first hydraulic cylinder, the second flow control device conveying head to rod chamber fluid flow;

wherein net head chamber fluid flow of the head chamber equals a sum of the accumulator fluid flow and the h

Assignees

• Schroeder Kyle William
• Gehlhoff Wade Leo
• Eaton Corp

Inventors

• Schroeder Kyle William
• Gehlhoff Wade Leo

Classifications

• F15B1/024

  used as a supplementary power source, e.g. to store energy in idle periods to balance pump load · CPC title

• F15B21/14

  Energy-recuperation means · CPC title

• E02F9/2296

  Systems with a variable displacement pump · CPC title

• F15B11/024 Primary

  by means of differential connection of the servomotor lines, e.g. regenerative circuits · CPC title

• F15B11/006

  Hydraulic "Wheatstone bridge" circuits, i.e. with four nodes, P-A-T-B, and on-off or proportional valves in each link · CPC title