Shovel and method of controlling shovel

Patent metadata

Field	Value
Publication number	US-9574329-B2
Application number	US-201414197305-A
Country	US
Kind code	B2
Filing date	Mar 5, 2014
Priority date	Sep 9, 2011
Publication date	Feb 21, 2017
Grant date	Feb 21, 2017

Abstract

A shovel includes a plurality of hydraulic actuators including a first hydraulic actuator and a second hydraulic actuator, a main pump, a hydraulic pump-motor configured to function as a hydraulic motor by using hydraulic oil flowing out of the first hydraulic actuator and configured to function as a hydraulic pump, a control valve configured to control a flow of the hydraulic oil in the plurality of hydraulic actuators, a first oil passage to connect the main pump with the second hydraulic actuator through the control valve, and a second oil passage to connect the hydraulic pump-motor with the second hydraulic actuator. The second oil passage meets the first oil passage between the control valve and the second actuator.

First claim

What is claimed is:

1. A shovel, comprising:
a plurality of hydraulic actuators driven by using hydraulic oil and including a first hydraulic actuator and a second hydraulic actuator, the first hydraulic actuator and the second hydraulic actuator being driven by causing the hydraulic oil to flow thereinto and therefrom;
a first pressure detector configured to detect a first pressure of the hydraulic oil flowing out of the first hydraulic actuator;
a second pressure detector configured to detect a second pressure of the hydraulic oil in the second hydraulic actuator;
a main pump;
a hydraulic pump-motor configured to function as a hydraulic motor by using the hydraulic oil flowing out of the first hydraulic actuator upon detecting that the first pressure detected by the first pressure detector is higher than or equal to a predetermined threshold pressure that is higher than the second pressure detected by the second pressure detector, and configured to function as a hydraulic pump upon detecting that the first pressure is lower than the predetermined threshold pressure;
a control valve configured to control a flow of the hydraulic oil in the plurality of hydraulic actuators;
a first oil passage to connect the main pump with the second hydraulic actuator through the control valve; and
a second oil passage to connect the hydraulic pump-motor with the second hydraulic actuator, the second oil passage meeting the first oil passage between the control valve and the second actuator,
wherein the hydraulic pump-motor suctions the hydraulic oil flowing out of the first hydraulic actuator and discharges the hydraulic oil to the second hydraulic actuator.

2. The shovel of claim 1 , further comprising:
a third oil passage to connect the first hydraulic actuator to the hydraulic pump-motor; and
an electromagnetic valve arranged in the third oil passage, the electromagnetic valve being opened to communicate the first hydraulic actuator with the hydraulic pump-motor in driving the first hydraulic actuator.

3. The shovel of claim 1 ,
wherein the first hydraulic actuator is a boom cylinder configured to drive a boom, and
the hydraulic pump-motor functions as the hydraulic motor by using the hydraulic oil flowing out of the boom cylinder in lowering the boom.

4. The shovel of claim 1 ,
wherein the first hydraulic actuator is a boom cylinder configured to drive a boom, and
the hydraulic pump-motor functions as the hydraulic pump to supply the hydraulic oil to the boom cylinder in lifting the boom.

5. The shovel of claim 1 ,
wherein the first hydraulic actuator is a boom cylinder configured to drive a boom, and
the hydraulic pump-motor functions as the hydraulic pump to supply the hydraulic oil, when the boom is not driven and at least one work element other than the boom is driven, to at least one of the plurality of hydraulic actuators configured to drive the at least one work element.

6. The shovel of claim 1 , wherein the hydraulic pump-motor that functions as the hydraulic pump increases the first pressure of the hydraulic oil flowing out of the first hydraulic actuator and discharges the hydraulic oil at a third pressure higher than the second pressure in the second hydraulic actuator.

7. The shovel of claim 6 , wherein the third pressure is the predetermined threshold pressure.

8. The shovel of claim 1 , wherein the hydraulic pump-motor that functions as the hydraulic motor decreases the first pressure of the hydraulic oil flowing out of the first hydraulic actuator and discharges the hydraulic oil at a third pressure lower than the first pressure when the first pressure of the hydraulic oil flowing out of the first hydraulic actuator is higher than the second pressure of the hydraulic oil in the second hydraulic actuator by a predetermined pressure amount or higher.

9. The shovel of claim 8 , wherein the third pressure is the predetermined threshold pressure.

10. The shovel of claim 1 , wherein an oil passage capable of directly supplying the hydraulic oil flowing out of the first hydraulic actuator to the second hydraulic actuator is provided between the first hydraulic actuator and the second hydraulic actuator.

11. The shovel of claim 1 , wherein the first hydraulic actuator is a boom cylinder, and the second hydraulic actuator is an arm cylinder.

12. The shovel of claim 1 , wherein the first hydraulic actuator is an arm cylinder, and the second hydraulic actuator is a boom cylinder.

13. The shovel of claim 1 , further comprising:
a hydraulic oil tank storing the hydraulic oil therein,
wherein part of the hydraulic oil flowing out of the first hydraulic actuator is caused to flow into the hydraulic pump-motor, and the other part of the hydraulic oil flowing out of the first hydraulic actuator is caused to discharge to the hydraulic oil tank through the control valve.

14. A method of controlling a shovel, the shovel including,
a plurality of hydraulic actuators including a first hydraulic actuator and a second hydraulic actuator;
a main pump;
a hydraulic pump-motor configured to function as a hydraulic motor by using hydraulic oil flowing out of the first hydraulic actuator, and configured to function as a hydraulic pump;
a control valve configured to control a flow of the hydraulic oil in the plurality of hydraulic actuators;
a first oil passage to connect the main pump with the second hydraulic actuator through the control valve; and
a second oil passage to connect the hydraulic pump-motor with the second hydraulic actuator,
the method, comprising steps of:
causing the hydraulic oil flowing through the second oil passage to merge into the hydraulic oil flowing through the first oil passage between the control valve and the second actuator;
detecting a first pressure of the hydraulic oil flowing out of the first hydraulic actuator;
detecting a second pressure of the hydraulic oil in the second hydraulic actuator;
causing the hydraulic pump-motor to function as the hydraulic motor by using the hydraulic oil flowing out of the first hydraulic actuator upon detecting that the detected first pressure is higher than or equal to a predetermined threshold pressure that is higher than the detected second pressure; and
causing the hydraulic pump-motor to function as the hydraulic pump upon detecting that the first pressure is lower than the predetermined threshold pressure,
wherein the hydraulic pump-motor suctions the hydraulic oil from the first hydraulic oil actuator and discharges the hydraulic oil to the second hydraulic actuator.

15. The method of claim 14 , wherein an electromagnetic valve arranged in a third oil passage connecting the first hydraulic actuator to the hydraulic pump-motor is opened to communicate the first hydraulic actuator with the hydraulic pump-motor when driving the first hydraulic actuator.

16. The method of claim 14 , wherein the hydraulic pump-motor increases the first pressure of the hydraulic oil flowing out of the first hydraulic actuator and discharges the hydraulic oil at a third pressure higher than the second pressure of the hydraulic oil in the second hydraulic actuator.

17. A shovel, comprising:
a plurality of hydraulic actuators driven by using hydraulic oil and including a first hydraulic actuator and a second hydraulic actuator, the first hydraulic actuator and the second hydraulic actuator being driven by causing the hydraulic oil to flow thereinto and therefrom;
a first pressure detector configured to detect a first pressure of the hydraulic oil flowing out of the first hydraulic actuator;
a second pressure

Assignees

• Sumitomo Heavy Industries

Inventors

• Wu Chunnan

Classifications

• E02F9/2075

  of the hybrid type (for vehicles in general B60W20/00) · CPC title

• E02F9/2296

  Systems with a variable displacement pump · CPC title

• F15B2211/20576

  with multiple pumps · CPC title

• F15B21/14

  Energy-recuperation means · CPC title

• E02F9/2217

  with energy recovery arrangements, e.g. using accumulators, flywheels · CPC title