JP2019100512A - Operation detection device of fluid pressure actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an operation of a fluid pressure actuator with an inexpensive and simple structure. An operation detection device 30 differentiates the detection pressure of a first pressure detection unit 31 or a second pressure detection unit 32 that changes depending on the adjustment of the air flow rate by a first flow rate adjustment unit 23 or a second flow rate adjustment unit 24. A control device 25 is provided for calculating the speed change amount of the piston 13 and integrating the calculated speed change amount of the piston 13 to calculate the displacement amount of the piston 13. Therefore, the control device 25 detects the displacement amount of the piston 13 only by using the detection pressure of the first pressure detection unit 31 or the second pressure detection unit 32 without using the magnetic strain type sensor. Therefore, the pneumatic cylinder 10 Operation detection can be performed with an inexpensive and simple structure. [Selection diagram] Fig. 1

Description

  The present invention relates to a motion detection device for a fluid pressure actuator.

  Generally, in a pneumatic cylinder as a fluid pressure actuator, a piston, which is a moving member, is accommodated in the cylinder chamber, and the cylinder chamber is partitioned by the piston into a first pressure application chamber and a second pressure application chamber. In addition, the pneumatic cylinder has a first supply / discharge port in communication with the first pressure application chamber, and a second supply / discharge port in communication with the second pressure application chamber. The first supply and discharge port is connected to a first supply and discharge flow path for supplying and discharging air as a fluid to the first supply and discharge port. Further, a second supply / discharge flow path for supplying / discharging air to the second supply / discharge port is connected to the second supply / discharge port.

  A switching valve is connected to the first supply and discharge passage and the second supply and discharge passage. The switching valve supplies air from the air supply source, which is a fluid supply source, to the first pressure application chamber via the first supply / discharge flow passage and the first supply / discharge port, and at the same time, air in the second pressure application chamber It is possible to switch to the first switching state of discharging to the atmosphere via the supply and discharge port and the second supply and discharge passage. Further, the switching valve supplies the air from the air supply source to the second pressure application chamber via the second supply / discharge channel and the second supply / discharge port, and the air of the first pressure application chamber as the first supply / discharge port. And can be switched to a second switching state of discharging to the atmosphere via the first supply and discharge passage. Then, when the switching valve is switched to the first switching state, the piston linearly moves in the cylinder chamber from the first stroke end located in the movement direction of the piston to the second stroke end. Further, by switching the switching valve to the second switching state, the piston linearly moves in the cylinder chamber from the second stroke end toward the first stroke end.

  Further, as a method of controlling the moving speed of the piston of such a pneumatic cylinder, for example, a first flow rate adjusting unit and a second flow rate adjusting unit provided respectively in the first supply and discharge passage and the second supply and discharge passage are used. The meter-in control method and the meter-out control method that have been used are generally known.

  In the meter-in control method, for example, when the switching valve is switched to the first switching state, the flow rate of the air supplied to the first pressure application chamber via the first supply / discharge passage and the first supply / discharge port is (1) The moving speed from the first stroke end to the second stroke end in the piston is controlled by adjusting by the flow rate adjusting unit. Also, for example, when the switching valve is switched to the second switching state, the flow rate of the air supplied to the second pressure action chamber via the second supply and discharge passage and the second supply and discharge port is adjusted to the second flow rate By adjusting by the part, the moving speed from the second stroke end to the first stroke end in the piston is controlled.

  In the meter-out control method, for example, when the switching valve is switched to the first switching state, the air discharged from the second pressure application chamber to the atmosphere via the second supply / discharge port and the second supply / discharge passage. The flow rate is adjusted by the second flow rate adjusting unit to control the moving speed from the first stroke end to the second stroke end in the piston. Also, for example, when the switching valve is switched to the second switching state, the flow rate of the air discharged from the first pressure action chamber to the atmosphere through the first supply / discharge port and the first supply / discharge passage is set to the first By adjusting by the flow rate adjusting unit, the moving speed from the second stroke end to the first stroke end in the piston is controlled.

  Thus, in the pneumatic cylinder, either the meter-in control method or the meter-out control method is adopted, and the flow rate of air is adjusted using the first flow rate adjusting unit and the second flow rate adjusting unit. The piston linearly moves in the cylinder chamber at a preset moving speed.

  By the way, in the pneumatic cylinder, while the piston is moving between the first stroke end and the second stroke end, some abnormality may occur and the moving speed of the piston may change abnormally. For example, in Patent Document 1, a magnetostrictive sensor is used to perform such operation detection of a pneumatic cylinder. The magnetostrictive sensor can continuously detect the position of the piston moving linearly in the cylinder chamber. Therefore, by using the magnetostrictive sensor, the operation of the pneumatic cylinder can be detected such that the moving speed of the piston changes abnormally.

JP-A-9-329409

  However, since the magnetostrictive sensor has a complicated structure for assembling to the pneumatic cylinder or the magnetostrictive sensor itself is expensive, it is difficult to say that it is an effective configuration for detecting the operation of the pneumatic cylinder. was there.

  The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a fluid pressure actuator motion detection device capable of performing motion detection of a fluid pressure actuator with an inexpensive and simple structure. It is in.

  A fluid pressure actuator motion detection device that solves the above problems includes a cylinder chamber, a movable member that linearly moves in the cylinder chamber, and a first pressure acting chamber and a second pressure that are respectively partitioned by the movable member in the cylinder chamber. And a second supply / discharge port communicating with the second pressure action chamber, the first supply / discharge port communicating with the first pressure action chamber, and the first supply / discharge port A first supply / discharge flow path for supplying / discharging a fluid to the first supply / discharge port is connected, and a second supply / discharge port supplies / discharges a fluid to the second supply / discharge port. Supply / discharge of fluid to / from the first pressure working chamber and the second pressure working chamber is performed by the switching valve connected to the first flow / discharge channel and the second supply / discharge channel. And the first supply and discharge passage and the second supply and discharge By adjusting the flow rate of the fluid using the first flow rate adjusting unit and the second flow rate adjusting unit respectively provided in the passage, the fluid in which the moving member linearly moves in the cylinder chamber at a preset moving speed It is an operation detection device of a pressure actuator, and the 1st pressure detection part which detects the pressure of the 1st pressure action room, the 2nd pressure detection part which detects the pressure of the 2nd pressure action room, and the 1st above-mentioned flow Change in speed of the moving member by calculating the change in speed of the moving member by differentiating the pressure detected by the first pressure detection unit or the second pressure detection unit, which changes as the flow rate of the fluid is adjusted by the adjustment unit or the second flow rate adjustment unit An amount calculation unit, and a displacement amount calculation unit that integrates the velocity change amount of the moving member calculated by the velocity change amount calculation unit to calculate the displacement amount of the moving member.

  In the fluid pressure actuator motion detection device, after the initial motion of the fluid pressure actuator, the calculated displacement of the moving member is compared with the displacement of the moving member obtained by the initial motion of the fluid pressure actuator. The apparatus may further include a determination unit that determines whether the operation of the fluid pressure actuator is abnormal.

  In the operation detection device of the fluid pressure actuator, the first pressure detection unit is disposed between the first supply and discharge port and the first flow rate adjustment unit in the first supply and discharge passage, and the second pressure The detection unit may be disposed between the second supply and discharge port and the second flow rate adjustment unit in the second supply and discharge passage.

  According to the present invention, the operation detection of the fluid pressure actuator can be performed with an inexpensive and simple structure.

The whole block diagram of the pneumatic circuit in an embodiment. The graph which shows the fluctuation waveform of the detection pressure by the 2nd pressure detection part, and the fluctuation waveform of the displacement amount of the piston detected by the magnetostrictive sensor which is a comparative example. The graph which shows the fluctuation waveform of the speed change amount of a piston. The graph which shows the fluctuation waveform of the displacement amount of a piston.

  Hereinafter, an embodiment in which a fluid pressure actuator motion detection device is embodied will be described according to FIGS. 1 to 4. The motion detection device of the fluid pressure actuator according to the present embodiment detects the motion of a pneumatic cylinder as a fluid pressure actuator.

  As shown in FIG. 1, the pneumatic cylinder 10 has a cylinder tube 11, a cylinder chamber 12 formed in the cylinder tube 11, and a piston 13 as a moving member accommodated in the cylinder chamber 12. There is. The piston 13 reciprocates linearly in the cylinder chamber 12. A piston rod 14 is integrally provided on the piston 13. The piston rod 14 can be inserted into and withdrawn from the cylinder tube 11 as the piston 13 reciprocates linearly.

  The inside of the cylinder chamber 12 is divided by the piston 13 into a first pressure application chamber 15 and a second pressure application chamber 16. The cylinder tube 11 is provided with a first supply / discharge port 17 in communication with the first pressure application chamber 15 and a second supply / discharge port 18 in communication with the second pressure application chamber 16.

  The first supply and discharge port 19 is connected to a first supply and discharge passage 19 for supplying and discharging air, which is a fluid, to the first supply and discharge port 17. Connected to the second supply / discharge port 18 is a second supply / discharge flow passage 20 for supplying / discharging air to the second supply / discharge port 18. A switching valve 21 is connected to the first supply / discharge channel 19 and the second supply / discharge channel 20. The switching valve 21 switches the supply and discharge of air to and from the first pressure application chamber 15 and the second pressure application chamber 16.

  The switching valve 21 supplies the air from the air supply source 22 which is a fluid supply source to the first pressure application chamber 15 via the first supply / discharge channel 19 and the first supply / discharge port 17 and the second pressure application chamber. It is possible to switch to a first switching state in which the air of 16 is discharged to the atmosphere via the second supply / discharge port 18 and the second supply / discharge flow passage 20. Further, the switching valve 21 supplies the air from the air supply source 22 to the second pressure action chamber 16 via the second supply / discharge flow passage 20 and the second supply / discharge port 18 and the air of the first pressure action chamber 15. Can be switched to the second switching state of discharging to the atmosphere via the first supply / discharge port 17 and the first supply / discharge passage 19.

  Then, the switching valve 21 is switched to the first switching state, whereby the piston 13 linearly moves in the cylinder chamber 12 from the first stroke end located in the moving direction of the piston 13 toward the second stroke end. Further, as the switching valve 21 is switched to the second switching state, the piston 13 linearly moves in the cylinder chamber 12 from the second stroke end toward the first stroke end.

  A first flow rate adjustment unit 23 is provided in the first supply / discharge flow passage 19. The first flow rate adjusting unit 23 is disposed between the first supply / discharge port 17 and the switching valve 21 in the first supply / discharge flow passage 19. The second flow rate adjusting unit 24 is provided in the second supply / discharge flow passage 20. The second flow rate adjusting unit 24 is disposed between the second supply and discharge port 18 and the switching valve 21 in the second supply and discharge passage 20. The first flow rate adjusting unit 23 and the second flow rate adjusting unit 24 are speed control valves having check valves 23a and 24a and variable throttle valves 23b and 24b, respectively.

  The valve opening degree of each of the variable throttle valves 23 b and 24 b of the first flow rate adjusting unit 23 and the second flow rate adjusting unit 24 is controlled by the control device 25. Then, the flow rate of air is adjusted using the first flow rate adjusting unit 23 and the second flow rate adjusting unit 24 so that the piston 13 linearly moves in the cylinder chamber 12 at a moving speed set in advance.

  In the present embodiment, a meter out control method is adopted as a method of controlling the moving speed of the piston 13. In the meter-out control method, for example, when the switching valve 21 is switched to the first switching state, the check valve 23 a of the first flow rate adjusting unit 23 is connected to the air supply source 22 via the first supply / discharge passage 19. The flow of air toward the first supply / discharge port 17 is permitted, and the air from the air supply source 22 is supplied to the first pressure working chamber 15 via the first supply / discharge flow passage 19 and the first supply / discharge port 17 . On the other hand, the valve opening degree of the variable throttle valve 24 b of the second flow rate adjusting unit 24 is controlled by the control device 25, and the atmosphere from the second pressure action chamber 16 through the second supply / discharge port 18 and the second supply / discharge flow passage 20 The flow rate of the air discharged to the valve is adjusted by the variable throttle valve 24b. Thereby, the moving speed from the first stroke end to the second stroke end in the piston 13 is controlled.

  In addition, for example, when the switching valve 21 is switched to the second switching state, the check valve 24 a of the second flow rate adjusting unit 24 receives the second supply and discharge from the air supply source 22 via the second supply and discharge passage 20. The flow of air toward the port 18 is permitted, and the air from the air supply source 22 is supplied to the second pressure application chamber 16 via the second supply / discharge flow passage 20 and the second supply / discharge port 18. On the other hand, the valve opening degree of the variable throttle valve 23 b of the first flow rate adjusting unit 23 is controlled by the control device 25, and the atmosphere from the first pressure action chamber 15 through the first supply / discharge port 17 and the first supply / discharge flow path 19 The flow rate of the air discharged to the valve is adjusted by the variable throttle valve 23b. Thereby, the moving speed from the second stroke end to the first stroke end in the piston 13 is controlled.

  The pneumatic cylinder 10, the first supply / discharge flow path 19, the second supply / discharge flow path 20, the switching valve 21, the first flow rate adjustment unit 23, and the second flow rate adjustment unit 24 are pneumatic pressures through which the air from the air supply source 22 flows. The circuit 1 is configured.

  The motion detection device 30 that detects the motion of the pneumatic cylinder 10 includes a first pressure detection unit 31 that detects the pressure of the first pressure application chamber 15 and a second pressure detection unit 32 that detects the pressure of the second pressure application chamber 16. And have. The first pressure detection unit 31 is disposed between the first supply and discharge port 17 and the first flow rate adjustment unit 23 in the first supply and discharge passage 19. The second pressure detection unit 32 is disposed between the second supply / discharge port 18 and the second flow rate adjustment unit 24 in the second supply / discharge flow passage 20.

  The first pressure detection unit 31 and the second pressure detection unit 32 are electrically connected to the control device 25 respectively. The first pressure detection unit 31 and the second pressure detection unit 32 are analog output pressure transducers that output a voltage value proportional to the detected pressure to the control device 25. The control device 25 performs digital conversion (AD conversion) on analog signals output from the first pressure detection unit 31 and the second pressure detection unit 32. The sampling cycle in this case is, for example, 1 ms or less. In addition, the control device 25 may perform moving average processing on the converted digital signal as necessary.

  The control device 25 differentiates the pressure detected by the first pressure detection unit 31 or the second pressure detection unit 32 which is changed by adjustment of the flow rate of air by the first flow rate adjustment unit 23 or the second flow rate adjustment unit 24. A speed change amount calculation program for calculating the speed change amount is stored in advance. Therefore, the control device 25 functions as a speed change amount calculation unit that calculates the speed change amount of the piston 13 by differentiating the pressure detected by the first pressure detection unit 31 or the second pressure detection unit 32.

  Further, a displacement amount calculation program for calculating the displacement amount of the piston 13 by integrating the calculated velocity change amount of the piston 13 is stored in advance. Thus, the control device 25 also functions as a displacement amount calculation unit that integrates the calculated velocity change amount of the piston 13 to calculate the displacement amount of the piston 13.

  In FIG. 2, for example, the switching valve 21 is switched to the first switching state, and the fluctuation waveform of the pressure detected by the second pressure detector 32 when the piston 13 moves from the first stroke end to the second stroke end. The (pressure waveform) is indicated by a solid line L1. Further, in FIG. 2, as a comparative example, a variation waveform (output waveform) of the displacement amount of the piston 13 detected by using a magnetostrictive sensor is indicated by a two-dot chain line L2. As can be seen by comparing the solid line L1 and the two-dot chain line L2 in FIG. 2, the fluctuation waveform of the pressure detected by the second pressure detection unit 32 correlates with the fluctuation waveform of the displacement amount of the piston 13 detected by the magnetostrictive sensor. There is no

  In FIG. 3, a fluctuation waveform (velocity waveform) of the velocity change amount of the piston 13 obtained by differentially calculating the pressure detected by the second pressure detector 32 is indicated by a solid line L3. Further, in FIG. 3, as a comparative example, a variation waveform (velocity waveform) of the velocity variation of the piston 13 obtained by differentially calculating the displacement of the piston 13 detected by the magnetostrictive sensor is indicated by a two-dot chain line L4. It shows. As the inventor sees by comparing the solid line L3 with the two-dot chain line L4 in FIG. 3, the fluctuation waveform of the speed change amount of the piston 13 obtained by differentially calculating the pressure detected by the second pressure detection unit 32. It has been found that there is a correlation with the fluctuation waveform of the velocity change amount of the piston 13 obtained by differentially calculating the displacement amount of the piston 13 detected by the magnetostrictive sensor.

  In FIG. 4, a variation waveform of the displacement amount of the piston 13 obtained by integrating and calculating the velocity change amount of the piston 13 obtained by differentially calculating the pressure detected by the second pressure detection unit 32 is indicated by a solid line L5. There is. Further, in FIG. 4, as a comparative example, a fluctuation waveform of the displacement amount of the piston 13 detected by the magnetostrictive sensor is indicated by a two-dot chain line L2. The two-dot chain line L2 shown in FIG. 4 is the same as the fluctuation waveform of the displacement amount of the piston 13 detected by the magnetostrictive sensor shown by the two-dot chain line L2 in FIG. As the inventor sees by comparing the solid line L5 with the two-dot chain line L2 in FIG. 4, the speed change amount of the piston 13 obtained by differentially calculating the pressure detected by the second pressure detection unit 32 is integrated It has been found that the fluctuation waveform of the displacement amount of the piston 13 obtained by performing the correlation has a correlation with the fluctuation waveform of the displacement amount of the piston 13 detected by the magnetostrictive sensor.

  Therefore, the control device 25 of the present embodiment changes the pressure detected by the first pressure detection unit 31 or the second pressure detection unit 32 which is changed by the adjustment of the flow rate of air by the first flow rate adjustment unit 23 or the second flow rate adjustment unit 24. The amount of change in speed of the piston 13 is calculated by differentiation, and the amount of change in speed of the calculated piston 13 is integrated to calculate the amount of displacement of the piston 13.

  The controller 25 prestores parameters such as the stroke amount of the piston 13 of the pneumatic cylinder 10 being used and the diameter of the piston. The displacement amount of the piston 13 obtained by the initial operation of the pneumatic cylinder 10 is stored as a baseline. For example, in the control device 25, the fluctuation waveform of the displacement amount of the piston 13 indicated by the solid line L5 in FIG. 4 is stored as a baseline.

  Here, "displacement amount of piston 13 obtained by initial operation of pneumatic cylinder 10" is "displacement amount of piston 13 obtained by initial operation when pneumatic cylinder 10 is used for the first time". The control device 25 may store, as a baseline, an average value of displacement amounts of the piston 13 obtained by using the pneumatic cylinder 10 for the first time and performing a plurality of operations thereafter.

  For example, the fluctuation waveform of the displacement amount of the piston 13 calculated by the control device 25 is a fluctuation waveform as indicated by a broken line L6 in FIG. 4 and a fluctuation waveform (base line) of the displacement amount of the piston 13 indicated by a solid line L5. In comparison, when a certain difference occurs, it is determined that the operation of the pneumatic cylinder 10 is abnormal. Therefore, the controller 25 compares the calculated displacement of the piston 13 with the displacement of the piston 13 obtained by the initial operation of the pneumatic cylinder 10 after the initial operation of the pneumatic cylinder 10, and the operation of the pneumatic cylinder 10 is abnormal. It also functions as a determination unit that determines whether or not

  As shown in FIG. 1, the control device 25 is electrically connected to the notification unit 26. Then, when determining that the operation of the pneumatic cylinder 10 is abnormal, the control device 25 transmits the determination result to the notification unit 26. Then, the notification unit 26 notifies the operator that the operation of the pneumatic cylinder 10 is abnormal. The notification unit 26 is, for example, a display for notifying the operator by displaying that the operation of the pneumatic cylinder 10 is abnormal.

Next, the operation of the present embodiment will be described.
The controller 25 moves the piston 13 linearly in the cylinder chamber 12 from the first stroke end to the second stroke end at a preset movement speed when the switching valve 21 is switched to the first switching state. 2) Control the valve opening degree of the variable throttle valve 24 b of the flow rate adjustment unit 24. Then, the control device 25 differentially calculates the pressure detected by the second pressure detection unit 32 to calculate the amount of change in speed of the piston 13 and integrates the calculated amount of change in speed of the piston 13 to calculate the amount of displacement of the piston 13 Calculate Thus, the position of the piston 13 linearly moving from the first stroke end to the second stroke end in the cylinder chamber 12 is continuously detected, and the piston 13 moves from the first stroke end to the second stroke end in the cylinder chamber 12. It is possible to detect the operation of the pneumatic cylinder 10 when moving linearly.

  In addition, when the switching valve 21 is switched to the second switching state, the control device 25 causes the piston 13 to linearly move in the cylinder chamber 12 from the second stroke end to the first stroke end at a preset moving speed. The opening degree of the variable throttle valve 23b of the first flow rate adjustment unit 23 is controlled. Then, the control device 25 differentially calculates the pressure detected by the first pressure detection unit 31 to calculate the amount of speed change of the piston 13 and integrates the calculated amount of speed change of the piston 13 to calculate the displacement of the piston 13 Calculate Thereby, the position of the piston 13 linearly moved from the second stroke end to the first stroke end in the cylinder chamber 12 is continuously detected, and the piston 13 moves from the second stroke end to the first stroke end in the cylinder chamber 12 It is possible to detect the operation of the pneumatic cylinder 10 when moving linearly.

  Then, after the initial operation of the pneumatic cylinder 10, the control device 25 compares the calculated displacement amount of the piston 13 with the baseline, and the operation of the pneumatic cylinder 10 is abnormal when a certain difference occurs. judge.

The following effects can be obtained in the above embodiment.
(1) The operation detection device 30 differentiates the pressure detected by the first pressure detection unit 31 or the second pressure detection unit 32 which changes as the flow rate of air is adjusted by the first flow rate adjustment unit 23 or the second flow rate adjustment unit 24. A controller 25 is provided to calculate the amount of change in speed of the piston 13 and integrate and calculate the amount of change in speed of the piston 13 to calculate the amount of displacement of the piston 13. According to this, since the motion detection device 30 can continuously detect the position of the piston 13 linearly moved in the cylinder chamber 12, the motion detection of the pneumatic cylinder 10 when the piston 13 linearly moves in the cylinder chamber 12 is detected. Is possible. Therefore, the control device 25 can detect the displacement amount of the piston 13 only by using the pressure detected by the first pressure detection unit 31 or the second pressure detection unit 32 without using the magnetostrictive sensor. The operation detection of the pneumatic cylinder 10 can be performed with an inexpensive and simple structure.

  (2) The controller 25 compares the calculated displacement of the piston 13 with the baseline after the initial operation of the pneumatic cylinder 10, and the operation of the pneumatic cylinder 10 is abnormal when a certain difference occurs. It is determined that According to this, a failure of the pneumatic cylinder 10 can be predicted. In addition, it is possible to identify an abnormal point of the pneumatic cylinder 10.

  (3) The first pressure detection unit 31 is disposed between the first supply / discharge port 17 and the first flow rate adjustment unit 23 in the first supply / discharge flow passage 19. According to this, compared to, for example, the case where the first pressure detection unit 31 is disposed between the first flow rate adjustment unit 23 and the switching valve 21 in the first supply / discharge flow passage 19, the first pressure detection is performed. The portion 31 can detect the pressure of the first pressure application chamber 15 with high accuracy. Further, the second pressure detection unit 32 is disposed between the second supply / discharge port 18 and the second flow rate adjustment unit 24 in the second supply / discharge flow passage 20. According to this, compared with, for example, the case where the second pressure detection unit 32 is disposed between the second flow rate adjustment unit 24 and the switching valve 21 in the second supply / discharge flow passage 20, the second pressure detection is performed. The portion 32 can detect the pressure of the second pressure application chamber 16 with high accuracy.

  (4) The control device 25 differentiates the pressure detected by the first pressure detection unit 31 or the second pressure detection unit 32 which is changed by the adjustment of the flow rate of air by the first flow rate adjustment unit 23 or the second flow rate adjustment unit 24. In order to calculate the speed change amount of the piston 13, it is possible to detect the speed change amount from the start of movement of the piston 13 to the stop linearly.

  (5) The first pressure detection unit 31 may be disposed at an arbitrary position between the first supply / discharge port 17 and the first flow rate adjustment unit 23 in the first supply / discharge flow passage 19, and the second pressure detection unit The first pressure detection unit 31 and the second pressure detection unit 32 may be disposed at any position between the second supply / discharge port 18 and the second flow rate adjustment unit 24 in the second supply / discharge flow passage 20. 32 installability is good.

  (6) The control device 25 can detect the displacement amount of the piston 13 only by using the pressure detected by the first pressure detection unit 31 or the second pressure detection unit 32 without using the magnetostrictive sensor. The displacement amount of the piston 13 can be detected accurately with little influence by the electrical disturbance noise.

  (7) Since the magnetostrictive sensor is assembled to the pneumatic cylinder 10, it is necessary to change the assembling position of the magnetostrictive sensor to the pneumatic cylinder 10 depending on the size of the pneumatic cylinder 10 or the like. It may be necessary to change the size to fit the size of. However, in the present embodiment, only using the detection pressure of the first pressure detection unit 31 disposed in the first supply / discharge flow passage 19 and the second pressure detection unit 32 disposed in the second supply / discharge flow passage 20 Thus, the displacement amount of the piston 13 can be detected. Therefore, under the influence of the size of the pneumatic cylinder 10, the installation positions of the first pressure detection unit 31 and the second pressure detection unit 32 are changed, or the sizes of the first pressure detection unit 31 and the second pressure detection unit 32 themselves There is no need to change

The above embodiment may be modified as follows.
In the embodiment, after the initial operation of the pneumatic cylinder 10, the control device 25 compares the calculated displacement amount of the piston 13 with the baseline to determine whether the operation of the pneumatic cylinder 10 is abnormal or not. It does not have to function as The point is that the motion detection device 30 continuously detects the position of the piston 13 linearly moving in the cylinder chamber 12 and can detect the motion of the pneumatic cylinder 10 when the piston 13 linearly moves in the cylinder chamber 12 It may be a certain configuration.

  In the embodiment, the first pressure detection unit 31 may be disposed, for example, between the first flow rate adjustment unit 23 and the switching valve 21 in the first supply / discharge flow passage 19. Further, the second pressure detection unit 32 may be disposed, for example, between the second flow rate adjustment unit 24 and the switching valve 21 in the second supply / discharge flow passage 20. In short, as long as the first pressure detection unit 31 can detect the pressure in the first pressure application chamber 15, the installation position is not particularly limited, and the second pressure detection unit 32 performs the second pressure operation. The installation position is not particularly limited as long as the pressure of the chamber 16 can be detected.

  In the embodiment, the controller 25 performs real-time operation information such as the thrust of the pneumatic cylinder 10 in real time, using parameters such as the stroke amount and piston diameter of the piston 13 of the pneumatic cylinder 10 stored in advance. It may be calculated and output.

  In the embodiment, for example, the control device 25 may incorporate the temperature detected by the temperature sensor that detects the temperature of the air into the calculation of the detection of the displacement amount of the piston 13 to perform correction processing.

  In the embodiment, a control device other than the control device 25 for controlling the opening degree of the variable throttle valve 23b, 24b of each of the first flow rate adjusting portion 23 and the second flow rate adjusting portion 24 is a speed change amount calculating portion It may function as a displacement amount calculation unit and a determination unit.

  In the embodiment, a control device that functions as a speed change amount calculation unit, a control device that functions as a displacement amount calculation unit, and a control device that functions as a determination unit may be separately provided.

  In the embodiment, the notification unit 26 may not be a display, and may notify an operator, for example, that the operation of the pneumatic cylinder 10 is abnormal by lighting of a lamp.

  In the embodiment, the motion detection device 30 may perform motion detection of fluid pressure actuators other than the pneumatic cylinder 10. Therefore, the moving member for moving the cylinder chamber 12 is not limited to the piston 13.

  In the embodiment, a meter-in control method may be adopted as a method of controlling the moving speed of the piston 13. In the meter-in control method, for example, when the switching valve 21 is switched to the first switching state, the air supplied to the first pressure application chamber 15 via the first supply / discharge passage 19 and the first supply / discharge port 17 The moving speed of the piston 13 from the first stroke end to the second stroke end is controlled by adjusting the flow rate of the first flow adjusting section 23 by the first flow adjusting section 23. Also, for example, when the switching valve 21 is switched to the second switching state, the flow rate of air supplied to the second pressure application chamber 16 via the second supply / discharge flow passage 20 and the second supply / discharge port 18 By adjusting by the second flow rate adjusting unit 24, the moving speed of the piston 13 from the second stroke end to the first stroke end is controlled.

  When the switching valve 21 is switched to the first switching state, the controller 25 differentially calculates the pressure detected by the first pressure detector 31 to calculate the speed change amount of the piston 13 and calculates the speed change of the piston 13 calculated. The amount is integrated to calculate the displacement of the piston 13. Thus, the position of the piston 13 linearly moving from the first stroke end to the second stroke end in the cylinder chamber 12 is continuously detected, and the piston 13 moves from the first stroke end to the second stroke end in the cylinder chamber 12. It is possible to detect the operation of the pneumatic cylinder 10 when moving linearly.

  When the switching valve 21 is switched to the second switching state, the controller 25 differentially calculates the pressure detected by the second pressure detection unit 32 to calculate the speed change amount of the piston 13 and calculates the speed change of the piston 13 calculated. The amount is integrated to calculate the displacement of the piston 13. Thereby, the position of the piston 13 linearly moved from the second stroke end to the first stroke end in the cylinder chamber 12 is continuously detected, and the piston 13 moves from the second stroke end to the first stroke end in the cylinder chamber 12 It is possible to detect the operation of the pneumatic cylinder 10 when moving linearly.

  DESCRIPTION OF SYMBOLS 10 ... Pneumatic cylinder as a fluid pressure actuator, 12 ... cylinder chamber, 13 ... Piston as a movement member, 15 ... 1st pressure action chamber, 16 ... 2nd pressure action chamber, 17 ... 1st supply / discharge port, 18 ... 1st 2 Supply and discharge port, 19: first supply and discharge flow passage, 20: second supply and discharge flow passage, 21: switching valve, 23: first flow rate adjusting unit, 24: second flow rate adjusting unit, 25: calculation of speed change amount Control device that functions as a unit, displacement amount calculation unit and determination unit, 30 ... operation detection device, 31 ... first pressure detection unit, 32 ... second pressure detection unit.

Claims (3)

With the cylinder chamber,
A moving member linearly moving in the cylinder chamber;
A first pressure application chamber and a second pressure application chamber respectively defined by the moving member in the cylinder chamber;
A first supply / discharge port communicating with the first pressure application chamber;
And a second supply / discharge port in communication with the second pressure application chamber,
A first supply and discharge passage for supplying and discharging a fluid to and from the first supply and discharge port is connected to the first supply and discharge port, and the second supply and discharge port is connected to the second supply and discharge port. A second supply / discharge channel for supplying / discharging fluid to the
Supply and discharge of fluid to and from the first pressure acting chamber and the second pressure acting chamber are switched by a switching valve connected to the first supply and drain passage and the second supply and drain passage. The moving speed of the moving member is set in advance by adjusting the flow rate of the fluid using the first flow rate adjusting unit and the second flow rate adjusting unit respectively provided in the flow path and the second supply / discharge flow path. An operation detection device for a fluid pressure actuator which linearly moves in the cylinder chamber,
A first pressure detection unit that detects the pressure of the first pressure application chamber;
A second pressure detection unit that detects the pressure of the second pressure application chamber;
The speed change amount of the moving member is differentiated by differentiating the pressure detected by the first pressure detection unit or the second pressure detection unit, which changes as the flow rate of the fluid is adjusted by the first flow rate adjusting unit or the second flow rate adjusting unit. A speed change calculation unit to be calculated;
A displacement amount calculation unit that integrates the velocity change amount of the moving member calculated by the velocity change amount calculation unit to calculate the displacement amount of the moving member; and the operation detection of the fluid pressure actuator apparatus.   After the initial operation of the fluid pressure actuator, the calculated displacement of the moving member is compared with the displacement of the moving member obtained by the initial operation of the fluid pressure actuator, and the operation of the fluid pressure actuator is abnormal The operation detection device for a fluid pressure actuator according to claim 1, further comprising a determination unit that determines whether or not there is any. The first pressure detection unit is disposed between the first supply and discharge port and the first flow rate adjustment unit in the first supply and discharge passage.
The second pressure detection unit is disposed between the second supply and discharge port and the second flow rate adjustment unit in the second supply and discharge passage. The fluid pressure actuator's operation detection device of statement.