Cylinder operating condition monitoring device

Patent metadata

Field	Value
Publication number	US-10480549-B2
Application number	US-201715722647-A
Country	US
Kind code	B2
Filing date	Oct 2, 2017
Priority date	Oct 3, 2016
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

A microcomputer of a detector that constitutes part of a monitoring device calculates differential pressures (first differential pressure, second differential pressure) between a first pressure value detected by a first pressure sensor provided in a first tube and a second pressure value detected by a second pressure sensor provided in a second tube, and on the basis of the calculated differential pressure, determines whether or not a reciprocating motion operation of the piston is in an intermediate state between a normal state and an abnormal state.

First claim

What is claimed is:

1. An operating condition monitoring device for a cylinder, in which a first cylinder chamber is formed between a piston and one end in an interior of a cylinder main body, a second cylinder chamber is formed between the piston and another end in the interior of the cylinder main body, and fluid is supplied from a fluid supply source to the first cylinder chamber, or fluid is supplied from the fluid supply source to the second cylinder chamber, whereby the piston which is connected to a piston rod undergoes reciprocating motion between the one end and the other end inside the cylinder main body, comprising:
a first pressure detection unit adapted to detect a pressure value of the first cylinder chamber;
a second pressure detection unit adapted to detect a pressure value of the second cylinder chamber;
a differential pressure calculating unit adapted to calculate a differential pressure between the pressure value detected by the first pressure detection unit and the pressure value detected by the second pressure detection unit;
a determination unit adapted to determine, based on the differential pressure calculated by the differential pressure calculating unit, whether or not the reciprocating motion operation of the piston is in an intermediate state between a normal state and an abnormal state; and
a storage unit adapted to store the calculated differential pressure, in an event that, during reciprocating motion of the piston, the first pressure detection unit has detected the pressure value of the first cylinder chamber, the second pressure detection unit has detected the pressure value of the second cylinder chamber, and the differential pressure calculating unit has calculated the differential pressure of the respective pressure values;
wherein, at completion of the reciprocating motion operation, the determination unit determines whether or not the reciprocating motion operation is in the intermediate state based on the differential pressure that is stored in the storage unit.

2. The operating condition monitoring device for a cylinder according to claim 1 , wherein:
the fluid supply source supplies fluid to the first cylinder chamber through a first tube, or supplies fluid to the second cylinder chamber through a second tube;
the first pressure detection unit detects a first pressure value of the fluid inside the first tube, which is dependent on the pressure value of the first cylinder chamber;
the second pressure detection unit detects a second pressure value of the fluid inside the second tube, which is dependent on the pressure value of the second cylinder chamber; and
the differential pressure calculating unit calculates a differential pressure between the first pressure value and the second pressure value.

3. The operating condition monitoring device for a cylinder according to claim 1 , wherein the determination unit:
determines that the reciprocating motion operation of the piston is in the normal state, in a case that the differential pressure is less than a first differential pressure threshold value;
determines that the reciprocating motion operation is in the intermediate state in which a degradation in performance of the cylinder has occurred although the reciprocating motion operation is normal, in a case that the differential pressure is greater than or equal to the first differential pressure threshold value and less than a second differential pressure threshold value; and
determines that the reciprocating motion operation is in the abnormal state, in the case that the differential pressure is greater than or equal to the second differential pressure threshold value.

4. The operating condition monitoring device for a cylinder according to claim 1 , further comprising a timer unit adapted to measure a movement time of the piston between the one end and the other end inside the cylinder main body;
wherein the timer unit measures as the movement time a time zone from a point in time at which the piston starts moving from the one end or the other end inside the cylinder main body to a point in time at which the piston reaches the other end or the one end inside the cylinder main body and the differential pressure increases from a constant value; and
the determination unit determines whether or not the reciprocating motion operation of the piston is in the intermediate state based on the movement time.

5. The operating condition monitoring device for a cylinder according to claim 4 , wherein the determination unit:
determines that the reciprocating motion operation of the piston is in the normal state, in a case that the movement time lies within a first time period threshold value;
determines that the reciprocating motion operation is in the intermediate state in which a degradation in performance of the cylinder has occurred although the reciprocating motion operation is normal, in a case that the movement time deviates from the first time period threshold value and lies within a second time period threshold value; and
determines that the reciprocating motion operation is in the abnormal state, in a case that the movement time deviates from the second time period threshold value.

6. The operating condition monitoring device for a cylinder according to claim 1 , further comprising a notification unit adapted to provide a notification of a determination result of the determination unit.

Assignees

• Smc Corp

Inventors

• Fujiwara Atsushi

Classifications

• F15B15/1423 Primary

  Component parts; Constructional details · CPC title

• F15B2211/8855

  Compressible fluids, e.g. specific to pneumatics · CPC title

• F15B15/2838 Primary

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

• F15B15/14

  of the straight-cylinder type · CPC title

• F15B2211/765

  Control of position or angle of the output member · CPC title