US 2012/0055149 A1 · SEMI-CLOSED HYDRAULIC SYSTEMS

Abstract

A semi-closed hydraulic system for use with heavy equipment includes a double-acting cylinder, a reservoir, first and second electric motors, first and second electric pumps, a pressure sensor, and a controller. The double-acting cylinder has a rod end and a cap end, and the reservoir is designed to provide hydraulic fluid to and receive hydraulic fluid from the cap end of the double-acting cylinder. The first pump is connected to and designed to be driven by the first electric motor. Furthermore, the first pump is bi-directional and is intermediate to the rod end and the cap end of the double-acting cylinder, such that the first pump is designed to provide hydraulic fluid to the rod end from the cap end, and to the cap end from the rod end. In addition, the second pump is coupled to and designed to be driven by the second electric motor, where the second pump is intermediate to the cap end of the double-acting cylinder and the reservoir. The second pump is also bi-directional and designed to provide hydraulic fluid to the cap end from the reservoir, and to the reservoir from the cap end. The pressure sensor provides an output signal related to the pressure of hydraulic fluid of the rod end of the double-acting cylinder, and the controller is connected to the pressure sensor. The controller operates the first pump at least partially as a function of the output signal provided by the pressure sensor during operation of the semi-closed hydraulic system.

Claims20

Dependent claims

A semi-closed hydraulic system for use with heavy equipment, comprising:

a double-acting cylinder having a rod end and a cap end;
a reservoir configured to provide hydraulic fluid to and receive hydraulic fluid from the cap end of the double-acting cylinder;
a first electric motor;
a first pump coupled to the first electric motor and configured to be driven thereby, wherein the first pump is intermediate to the rod end and the cap end of the double-acting cylinder, wherein the first pump is bi-directional and configured to provide hydraulic fluid to the rod end from the cap end, and to also provide hydraulic fluid to the cap end from the rod end;
a second electric motor;
a second pump coupled to the second electric motor and configured to be driven thereby, wherein the second pump is intermediate to the cap end of the double-acting cylinder and the reservoir, wherein the second pump is bi-directional and configured to provide hydraulic fluid to the cap end from the reservoir, and to also provide hydraulic fluid to the reservoir from the cap end;
a pressure sensor providing an output signal related to the pressure of hydraulic fluid of the rod end of the double-acting cylinder, and
a controller coupled to the pressure sensor, wherein the controller operates the first pump at least partially as a function of the output signal provided by the pressure sensor during operation of the semi-closed hydraulic system.

5 more elements

A hydraulic system, comprising:

a double-acting cylinder having a rod end and a cap end;
a reservoir configured to provide hydraulic fluid to and receive hydraulic fluid from the cap end of the double-acting cylinder;
a first pump coupled intermediate to the rod end and the cap end of the double-acting cylinder, wherein the first pump is bi-directional and configured to provide hydraulic fluid to the rod end from the cap end of the double-acting cylinder, and to also provide hydraulic fluid to the cap end from the rod end of the double-acting cylinder;
a second pump coupled intermediate to the cap end of the double-acting cylinder and the reservoir, wherein the second pump is bi-directional and configured to provide hydraulic fluid to the cap end of the double-acting cylinder from the reservoir, and to also provide hydraulic fluid to the reservoir from the cap end of the double-acting cylinder;
a first pressure sensor in communication with hydraulic fluid of the rod end of the double-acting cylinder, wherein the first pump is controlled at least partially as a function of an output signal provided by the first pressure sensor during operation of the hydraulic system;
and
a second pressure sensor in communication with hydraulic fluid of the cap end of the double-acting cylinder, wherein the second pump is controlled at least partially as a function of an output signal provided by the second pressure sensor during operation of the hydraulic system.

4 more elements

Dependencies are inferred from the claim text.

Semi-closed hydraulic systems

Life of this patent

Semi-closed hydraulic systems

Life of this patent

Abstract

Claims20