Working machine control system

Patent metadata

Field	Value
Publication number	US-10072396-B2
Application number	US-201515113486-A
Country	US
Kind code	B2
Filing date	Jan 27, 2015
Priority date	Jan 31, 2014
Publication date	Sep 11, 2018
Grant date	Sep 11, 2018

Abstract

A working machine control system includes: a split-flow fluid pressure pump configured to discharge a working fluid from a first discharge port and a second discharge port; a communication switching valve configured to be switched by a switch signal when any one of a first operation valve and a second operation valve is switched so as to allow a first neutral passage and a second neutral passage to communicate with each other; a neutral cut valve configured to be switched by the switch signal so as to block communication between a tank and one of the first neutral passage and the second neutral passage for the first operation valve or the second operation valve that is not switched; and a discharge flow rate adjusting device configured to adjust the fluid pressure pump so as to reduce a discharge flow rate thereof when the switch signal is inputted from any one of the first operation valve and the second operation valve.

First claim

The invention claimed is:

1. A working machine control system configured to control a working machine including a first actuator and a second actuator, the working machine control system comprising:
a split-flow fluid pressure pump configured to discharge a working fluid from a first discharge port and a second discharge port;
a first circuit system to which the working fluid discharged from the first discharge port is supplied, the first circuit system including a first operation valve and a first neutral passage, the first operation valve being configured to control the first actuator, the first neutral passage allowing the first discharge port to communicate with a tank in a state where the first operation valve is placed at a normal position;
a second circuit system to which the working fluid discharged from the second discharge port is supplied, the second circuit system including a second operation valve and a second neutral passage, the second operation valve being configured to control the second actuator, the second neutral passage allowing the second discharge port to communicate with the tank in a state where the second operation valve is placed at a normal position;
a communication switching valve configured to be switched by a switch signal when any one of the first operation valve and the second operation valve is switched so as to allow the first neutral passage and the second neutral passage to communicate with each other;
a neutral cut valve provided in at least one of the first circuit system and the second circuit system, the neutral cut valve being configured to be switched by the switch signal so as to block communication between the tank and one of the first neutral passage and the second neutral passage for the other of the first operation valve and the second operation valve that is not switched; and
a discharge flow rate adjusting device configured to adjust the fluid pressure pump so as to reduce a discharge flow rate of the fluid pressure pump in a case where the switch signal is inputted from any one of the first operation valve and the second operation valve.

2. The working machine control system according to claim 1 ,
wherein the fluid pressure pump includes a swash plate whose inclination angle is adjusted by a single regulator to be controlled by a pilot pressure, and the inclination angle of the swash plate is adjusted in such a manner that the higher the pilot pressure acting on the regulator is, the more the discharge flow rate increases.

3. The working machine control system according to claim 2 ,
wherein the switch signal is a pilot pressure for switching the first operation valve or the second operation valve,
wherein the neutral cut valve includes a first neutral cut valve provided in the first circuit system and a second neutral cut valve provided in the second circuit system, and
wherein the discharge flow rate adjusting device includes:
a first high-pressure selection circuit configured to select the highest one of pilot pressures for switching the first operation valve to guide the selected pilot pressure to the communication switching valve and the second neutral cut valve by allowing communication of the selected pilot pressure so as to allow the first neutral passage and the second neutral passage to communicate with each other and block communication between the second neutral passage and the tank;
a second high-pressure selection circuit configured to select the highest one of pilot pressures for switching the second operation valve to guide the selected pilot pressure to the communication switching valve and the first neutral cut valve by allowing communication of the selected pilot pressure so as to allow the first neutral passage and the second neutral passage to communicate with each other and block communication between the first neutral passage and the tank;
a high-pressure selection valve configured to select higher one of the pilot pressures guided from the first high-pressure selection circuit and the second high-pressure selection circuit to cause the selected pilot pressure to act on the regulator; and
a differential pressure reduction valve configured to reduce the pilot pressure acting on the regulator as a pressure difference between the pilot pressures guided from the first high-pressure selection circuit and the second high-pressure selection circuit increases.

4. The working machine control system according to claim 3 ,
wherein the discharge flow rate adjusting device further includes a switching valve that is switched by the pilot pressure guided from the first high-pressure selection circuit and the pilot pressure guided from the second high-pressure selection circuit so that higher one of the pilot pressures guided from the first high-pressure selection circuit and the second high-pressure selection circuit is blocked and lower one of the pilot pressures is caused to act on the differential pressure reduction valve, and
wherein the differential pressure reduction valve reduces the pilot pressure acting on the regulator as a pressure difference between the pilot pressure acting on the regulator and the pilot pressure acting through the switching valve increases.

5. The working machine control system according to claim 2 ,
wherein the switch signal is an electric signal outputted via a switching operation for the first operation valve or the second operation valve,
wherein the neutral cut valve includes a first neutral cut valve provided in the first circuit system and a second neutral cut valve provided in the second circuit system, and
wherein the discharge flow rate adjusting device includes:
a pilot pump configured to generate a pilot pressure;
a first pressure reduction valve configured to guide, when the electric signal is inputted only from the first operation valve, the pilot pressure from the pilot pump to the communication switching valve and the second neutral cut valve so as to allow the first neutral passage and the second neutral passage to communicate with each other and block communication between the second neutral passage and the tank;
a second pressure reduction valve configured to guide, when the electric signal is inputted only from the second operation valve, the pilot pressure from the pilot pump to the communication switching valve and the first neutral cut valve so as to allow the first neutral passage and the second neutral passage to communicate with each other and block communication between the first neutral passage and the tank; and
a third pressure reduction valve configured to reduce, when the electric signal is inputted from any one of the first operation valve and the second operation valve, the pilot pressure guided from the pilot pump to the regulator.

Assignees

• Kyb Corp

Inventors

• Yoshida Nobuyoshi
• Inagaki Ikuo

Classifications

• F15B2211/428

  actuated by fluid pressure · CPC title

• E02F9/2239

  using two or more pumps with cross-assistance · CPC title

• F15B2211/30595

  with additional valves between the groups of valves for multiple output members · CPC title

• F15B2211/20553

  with pilot circuit, e.g. for controlling a swash plate · CPC title

• F15B13/022

  Flow-dividers; Priority valves · CPC title