Actuator-operation detecting apparatus

Patent metadata

Field	Value
Publication number	US-11022156-B2
Application number	US-201916527935-A
Country	US
Kind code	B2
Filing date	Jul 31, 2019
Priority date	Aug 29, 2018
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

An actuator-operation detecting apparatus is configured to check the operating state of a piston of an actuator. The actuator includes a double-acting cylinder, the piston that partitions the cylinder into a first pressure acting chamber and a second pressure acting chamber, and a rod connected to an end face of the piston facing the second pressure acting chamber. The actuator-operation detecting apparatus includes a first pressure detector to detect the pressure in the first pressure acting chamber, a second pressure detector to detect the pressure in the second pressure acting chamber, a differential amplifier circuit to calculate a thrust force acting on the piston based on the pressures detected by the first and second pressure detectors and the pressure-receiving area of the piston, and a microcomputer to monitor the operation of the piston based on the thrust force.

First claim

What is claimed is:

1. An actuator-operation detecting apparatus for an actuator, the actuator including: a double-acting cylinder; a piston slidably supported in the double-acting cylinder to partition an inside of the double-acting cylinder into a first pressure acting chamber and a second pressure acting chamber; and a rod coupled to an end face of the piston that faces the second pressure acting chamber, the actuator-operation detecting apparatus being configured to monitor an operating state of the piston,
wherein the actuator-operation detecting apparatus comprises:
a first pressure detector configured to detect pressure in the first pressure acting chamber;
a second pressure detector configured to detect pressure in the second pressure acting chamber;
a calculator configured to calculate a thrust force acting on the piston by considering that a first pressure-receiving area of the end face of the piston that faces the second pressure acting chamber is smaller by an outer diameter of the rod than a second pressure-receiving area of an end face of the piston that faces the first pressure acting chamber and subtracting a value obtained by multiplying a pressure value detected by the second pressure detector by a ratio of the first pressure-receiving area to the second pressure-receiving area from a pressure value detected by the first pressure detector; and
a monitor configured to check the operating state of the piston based on a sign of the thrust force.

2. The actuator-operation detecting apparatus according to claim 1 , wherein the monitor is configured to check the operating state of the piston based on a change rate of the thrust force.

3. The actuator-operation detecting apparatus according to claim 2 , wherein
the monitor is configured to:
determine whether the piston has started moving or has stopped moving; and if the piston is determined to have started moving,
determine whether the piston is moving toward an end face of the double-acting cylinder that faces the first pressure acting chamber or the piston is moving toward an end face of the double-acting cylinder that faces the second pressure acting chamber.

4. The actuator-operation detecting apparatus according to claim 1 , wherein
the monitor is configured to:
determine whether the piston has started moving or has stopped moving; and if the piston is determined to have started moving,
determine whether the piston is moving toward an end face of the double-acting cylinder that faces the first pressure acting chamber or the piston is moving toward an end face of the double-acting cylinder that faces the second pressure acting chamber.

5. The actuator-operation detecting apparatus according to claim 1 , wherein
the monitor checks the operating state of the piston by determining whether the piston is moving toward an end face of the double-acting cylinder that faces the first pressure acting chamber or the piston is moving toward an end face of the double-acting cylinder that faces the second pressure acting chamber.

Assignees

• Ckd Corp

Inventors

• Kondo Takemoto

Classifications

• F15B15/2838 Primary

  with out using position sensors, e.g. by volume flow measurement or pump speed · CPC title

• F15B2211/6313

  the pressure being a load pressure · CPC title

• F15B2211/857

  Monitoring of fluid pressure systems · CPC title

• F15B2211/7053

  Double-acting output members · CPC title

• F15B19/007 Primary

  Simulation or modelling · CPC title