JP2022050171A - Pressurized oil supply/discharge system - Google Patents

Abstract

To detect an abnormal state of a pressurized oil supply/discharge system that has not been detected conventionally.SOLUTION: A pump (1) driven by supplying compressed air supplies pressurized oil to a cylinder (10) via a flow passage. A three-way valve (2) provided in a middle part of the flow passage enables switching between a state where the pressurized oil is supplied from the pump (1) to the cylinder (10) and a state where the pressurized oil is discharged from the cylinder (10) to the outside. When pressure of the pressurized oil in the flow passage exceeds predetermined pressure, a pressure compensation valve (3) discharges the pressurized oil to the outside so that the pressure of the pressurized oil in the flow passage becomes below the predetermined pressure. A flow rate of the compressed air supplied to the pump (1) is detected by an air flow rate detection sensor (5). The pressure of the pressurized oil in the flow passage is detected by an oil pressure detection sensor (6).SELECTED DRAWING: Figure 1

Description

The present invention relates to a system for supplying and discharging pressure oil to an object to be supplied and discharged with pressure oil.

Conventionally, there is a pressure oil supply / discharge system of this type described in Patent Document 1 (Japanese Patent Laid-Open No. 3-181682). The prior art is configured as follows.
The pressure oil supply / discharge system has a pump and a three-way valve and a pressure guarantee valve provided in the middle of a flow path connecting the pump and a cylinder as a pressure supply / discharge object. The pump is configured such that a piston is driven by compressed air supplied from a compressed air source, and a plunger connected to the piston sends oil from an oil tank to a cylinder. The above-mentioned three-way valve is configured to switch between a state in which the pressure oil from the pump is supplied to the cylinder and a state in which the pressure oil in the cylinder is discharged to the outside. The pressure guarantee valve described above discharges the pressure oil to the outside when the pressure oil supplied from the pump exceeds a predetermined pressure so that the pressure oil falls below the predetermined pressure. A pressure detection switch provided in the flow path of the pressure oil connecting the pump and the cylinder detects whether or not the hydraulic pressure in the flow path is higher than a predetermined pressure.

Japanese Unexamined Patent Publication No. 3-181682

The above-mentioned prior art has the following problems.
Even when it is determined that the pressure oil in the flow path is in a normal state by detecting that the pressure is appropriate by the pressure detection switch, the pressure oil supply / discharge system is excessively operating. There may be an abnormal condition or an abnormal condition where there is a leak in the piping. Such an abnormal state cannot be detected only by the pressure detection switch.
An object of the present invention is to be able to detect an abnormal state of a pressure oil supply / discharge system that could not be detected in the past.

In order to achieve the above object, the present invention has the following configuration of a pressure oil supply / discharge system, for example, as shown in FIGS. 1 to 3 or 4.
The pump 1 is driven by the supply of compressed air, and the pump 1 discharges the pressure oil to the pressure oil supply / discharge target 10. A three-way valve 2 is provided in the middle of the flow path for supplying and discharging the pressure oil to the pressure oil supply / discharge target 10. The three-way valve 2 switches between a state in which the pressure oil is supplied from the pump 1 to the pressure oil supply / discharge object 10 and a state in which the pressure oil is discharged to the outside from the pressure oil supply / discharge object 10. When the pressure of the pressure oil in the flow path exceeds the set pressure, the pressure guarantee valve 3 discharges the pressure oil to the outside so that the pressure of the pressure oil in the flow path falls below the set pressure. The air flow rate detecting device 5 detects the flow rate of the compressed air supplied to or discharged from the pump 1. The hydraulic pressure detecting device 6 detects the pressure of the pressure oil in the flow path.

The above-mentioned invention has the following effects.
The air flow rate detecting device 5 and the hydraulic pressure detecting device 6 are provided. Thereby, in the pressure oil supply / discharge system of the present invention, the abnormal state that could not be detected by the conventional pressure oil supply / discharge system can be detected by the air flow rate detection device and the hydraulic pressure detection device 6.

In the present invention, it is preferable to add the following configurations (1) to (3).
(1) For example, as shown in FIGS. 1 to 3 or 4, the air pressure detecting device 4 detects the pressure of compressed air supplied to or discharged from the pump 1.
In this case, the abnormal state of the pressure oil supply / discharge system that could not be detected by the air flow rate detection device and the hydraulic pressure detection device is the detection result of the air flow rate detection device, the detection result of the hydraulic pressure detection device, and the detection result of the air pressure detection device. It is surely detected by combining.

(2) The control device 80 that receives signals from the air flow rate detection device 5 and the hydraulic pressure detection device 6 detects the state of the pressure oil supply / discharge system.
In this case, the control device reliably detects the abnormal state of the pressure oil supply / discharge system that could not be detected from the detection result of only the hydraulic pressure detection device by combining the detection results of the air flow rate detection device and the hydraulic pressure detection device.

(3) The control device 80 that receives signals from the air pressure detection device 4, the air flow rate detection device 5, and the hydraulic pressure detection device 6 detects the state of the pressure oil supply / discharge system.
In this case, the abnormal state of the pressure oil supply / discharge system, which could not be detected only by the detection result of the oil pressure detection device and the detection result of the air flow rate detection device, is detected by the air flow rate detection device, the air pressure detection device, and the oil pressure detection device. By combining them, the control device can reliably detect them.

FIG. 1 shows a first embodiment of the present invention and is a schematic view showing a partial cross-sectional view of a pressure oil supply / discharge system. FIG. 2 is a cross-sectional view showing the pump of the pressure oil supply / discharge system. FIG. 3 is a cross-sectional view showing a three-way valve and a pressure guarantee valve of the pressure oil supply / discharge system. FIG. 4 shows a second embodiment of the present invention, and is a schematic view showing a partial cross-sectional view of a pressure oil supply / discharge system.

The first embodiment of the present invention will be described with reference to FIG.
The pressure oil supply / discharge system includes a pump 1, a three-way valve 2, a pressure guarantee valve 3, an air pressure detection device 4, an air flow rate detection device 5, and a hydraulic pressure detection device 6.

Compressed air is supplied to the pump 1 from the compressed air source 7 through the pressure regulator 8. As a result, the pump 1 supplies the oil in the oil tank 9 to the cylinder (pressure oil supply / discharge target) 10 as pressure oil through the flow path.

As shown in FIG. 2, the pump 1 is configured as follows.
The casing 11 of the pump 1 is provided with a compressed air supply port 12 and an air discharge hole 13. Compressed air from the compressed air source 7 is supplied to the compressed air supply port 12. The compressed air drives the piston 15 provided in the casing 11 and then is discharged to the outside through the air discharge hole 13.

The lubrication port 17 and the discharge port 18 communicate with each other in the plunger chamber 16 formed in the pump 1. The oil tank 9 communicates with the oil supply port 17 via the flow path 20. The plunger 21 connected to the piston 15 is tightly inserted into the plunger chamber 16. When the plunger 21 is raised, the hydraulic pressure in the plunger chamber 16 decreases, and the oil in the oil tank 9 flows into the plunger chamber 16 from the refueling port 17 through the flow path 20. When the plunger 21 is lowered, the pressure oil in the plunger chamber 16 is sent out from the discharge port 18 to the three-way valve 2.

As shown in FIG. 3, the three-way valve 2 includes a housing 26, a directional switching valve body 27, and a directional switching mechanism 28. A valve chamber 29 is formed in the housing 26 in the vertical direction. The valve chamber 29 is vertically divided into a first chamber 31 and a second chamber 32 by a partition wall 30 formed inside the valve chamber 29. The first chamber 31 and the second chamber 32 are connected by a communication hole 33. A supply port 34 is formed in the housing 26, and the supply port 34 is communicated with the first chamber 31 via the inlet path 35. The entrance road 35 is opened on the ceiling surface of the first room 31. The supply port 34 is connected to the discharge port 18 of the pump 1. A pressure valve seat 36 is formed on the peripheral edge of the opening hole of the inlet passage 35. A check valve body 37 that can come into contact with the pressure supply valve seat 36 is inserted into the first chamber 31 so as to be movable in the vertical direction. A valve closing spring 38 is mounted between the lower surface of the check valve body 37 and the upper surface of the partition wall 30. A short-circuit prevention valve seat 39 is formed in an annular shape on the peripheral edge of the opening on the second chamber 32 side of the communication hole 33 formed in the partition wall 30. Further, an outlet passage 40 is opened on the bottom surface of the second chamber 32, and a return valve seat 41 is formed in an annular shape on the peripheral edge of the opening. The short-circuit prevention valve body 42 that can come into contact with the short-circuit prevention valve seat 39 is inserted into the second chamber 32 so as to be movable in the vertical direction. The return valve body 44 is inserted into the accommodating hole 43 formed in the lower portion of the short-circuit prevention valve body 42 so as to be movable in the vertical direction. Further, a separation spring 45 is mounted in the accommodating hole 43, and the separation spring 45 urges the short-circuit prevention valve body 42 and the return valve body 44 in a direction to separate from each other. More specifically, the separation spring 45 urges the short-circuit prevention valve body 42 toward the short-circuit prevention valve seat 39 and the return valve body 44 toward the return valve seat 41. The second chamber 32 communicates with the working chamber 47 of the cylinder 10 via the working port 46. Further, the outlet path 40 communicates with the oil tank 9 via the return port 48.

The direction switching mechanism 28 is provided under the second chamber 32 and is configured as follows. The cylinder hole 51 is formed so as to communicate with the second chamber 32 via the outlet path 40. The output member 52 is inserted into the cylinder hole 51 so as to be movable in the vertical direction. The output member 52 has a piston portion 53 formed in order from the lower side and an operation rod 54 projecting upward from the piston portion 53. The operation rod 54 is tightly inserted into the outlet path 40 so as to be movable in the vertical direction so as to be in contact with the return valve body 44. An advancing actuating chamber 55 is formed on the lower side of the piston portion 53, and an advancing actuating chamber 56 is formed on the upper side of the piston portion 53. The compressed air supply / discharge passage 57 is communicated with the advance operating chamber 55, and the compressed air from the compressed air source is supplied / discharged to the advance operating chamber 55 through the supply / discharge passage 57. Further, a retracting spring 58 is mounted in the retracting actuating chamber 56, and the retracting spring 58 urges the output member 52 downward.

When the hydraulic pressure of the operating port 46 abnormally rises due to thermal expansion of pressure oil, an external force, or the like, the pressure guarantee valve 3 releases the abnormal rising pressure to the outside, and the pressure inside the operating port 46 becomes equal to or lower than the set pressure. It is something to do.
The pressure guarantee valve 3 has a valve seat chamber 62, a relief valve chamber 63, and a spring chamber 64 that are coaxially communicated from the left side in the valve case 61. The valve seat chamber 62 is connected to the actuating port 46 of the three-way valve 2 through the flow path 65. Further, the relief valve chamber 63 is connected to the return port 48 of the three-way valve 2 through the flow path 66.

The valve seat member 67 is tightly inserted into the valve seat chamber 62 so as to be able to move forward and backward in the left-right direction. A communication hole 68 is formed on the lower side surface from the right end surface of the valve seat member 67. The throttle path 69 is formed by the fitting gap between the outer peripheral surface of the valve seat member 67 and the inner peripheral surface of the valve seat chamber 62. Further, the valve seat 70 is configured at the right end portion of the valve seat member 67.

The valve member 71 is inserted into the relief valve chamber 63 in a conservative manner so as to be able to move forward and backward in the left-right direction. An elastic member made of resin or the like is attached to the annular groove formed at the left end of the valve member 71. An annular valve surface 72 is formed at the left end of the elastic member, and the valve surface 72 faces the valve seat 70 so as to be in contact with the valve seat 70.

A relief spring 74 and a spring seat are mounted between the right end of the spring chamber 64 and the valve member 71. The relief spring 74 urges the valve member 71 to the left.

In the pressure guarantee valve 3 described above, when the oil pressure in the valve seat chamber 62 exceeds the pressure corresponding to the urging force of the relief spring 74, the valve surface 72 is separated from the valve seat 70 and the pressure guarantee valve 3 is opened. .. On the other hand, when the oil pressure of the valve seat chamber 62 becomes lower than the pressure corresponding to the urging force of the relief spring 74, the relief spring 74 presses the valve surface 72 against the valve seat 70, and the pressure guarantee valve 3 is closed. Ru.

The pressure guarantee valve 3 operates as follows.
In the initial state of FIG. 3, when pressure oil is supplied to the valve seat chamber 62 from the operation port 46 of the three-way valve 2, the oil pressure of the valve seat chamber 62 moves the valve seat member 67 to the right, and the pressure oil moves the valve seat member 67 to the right. The valve seat member 67 moves the valve member 71 to the right. As a result, the flange portion formed at the left end portion of the valve seat member 67 is received by the step portion in the valve seat chamber 62. Further, the pressure oil in the valve seat chamber 62 presses the valve member 71 to the right through the throttle passage 69 and the communication passage 68 in the valve seat chamber 62, and the valve surface 72 of the valve member 71 is valved by the relief spring 74. It is sealed and contacted with the valve seat 70 of the seat member 67, and the pressure guarantee valve 3 remains closed.

When the oil pressure in the valve seat chamber 62 exceeds the pressure corresponding to the urging force of the relief spring 74, the pressure guarantee valve 3 is opened, and the pressure oil in the valve seat chamber 62 is three-way with the relief valve chamber 63 and the flow path 66. The oil is discharged from the return port 48 of the valve 2 to the oil tank 9. Then, the oil pressure of the valve seat chamber 62 decreases, and the pressure oil force becomes lower than the pressure corresponding to the urging force of the relief spring 74. Then, the pressure guarantee valve 3 is closed.

The air pressure detection sensor (air pressure detection device) 4 and the air flow rate detection sensor (air flow rate detection device) 5 are provided in the middle of the flow path connecting the compressed air source 7 and the pump 1. Further, the hydraulic pressure detection sensor 6 is provided in the middle of the flow path connecting the operation port 46 of the three-way valve 2 and the operation chamber 47 of the cylinder 10.

The pressure oil supply / discharge system of the above embodiment operates as follows.
When the compressed air from the compressed air source 7 is supplied into the pump 1 through the compressed air supply port 12 of the pump 1, the compressed air drives the piston 15 in the vertical direction. At this time, the pressure of the compressed air in the flow path connecting the compressed air source 7 and the pump 1 is detected by the air pressure detection sensor 4, and the flow rate of the compressed air in the flow path is detected by the air flow rate detection sensor 5. Will be done. Then, when the plunger 21 connected to the piston 15 rises, the oil in the oil tank 9 is drawn into the plunger chamber 16 through the flow path 20 and the oil supply port 17, and the plunger 21 descends to cause the plunger 21. 21 pushes the oil in the plunger chamber 16 through the discharge port 18 to the supply port 34 of the three-way valve 2. The pressure oil supplied to the supply port 34 moves the check valve body 37 of the three-way valve 2 downward against the urging force of the valve closing spring 38 to open the check valve body 37. At this time, compressed air is not supplied to the operating chamber 55 for advancing the direction switching mechanism 28 of the three-way valve 2, and the piston portion 53 of the output member 52 is moved downward by the urging force of the retracting spring 58. .. Therefore, a gap is formed between the upper end surface of the operation rod 54 of the output member 52 and the lower end surface of the return valve body 44. Next, the pressure oil of the supply port 34 flows into the first chamber 31 of the valve chamber 29. The pressure oil in the first chamber 31 moves the return valve body 44 downward against the urging force of the separation spring 45, and closes the return valve body 44. Then, the pressure oil in the first chamber 31 is supplied to the operating chamber 47 of the cylinder 10 through the communication passage 33, the second chamber 32, and the operating port 46. Then, the piston of the cylinder 10 advances upward. When the piston is stopped at the upper limit position, the pressure of the pressure oil in the working chamber 47 rises to a predetermined pressure. The predetermined pressure is detected by the hydraulic pressure detection sensor 6. Then, the pressure in the flow path from the discharge port 18 of the pump 1 to the cylinder 10 becomes higher than the pressure in the plunger chamber 16 of the pump 1, and the pump 1 cannot push out the pressure oil. As a result, the driving of the piston 15 of the pump 1 is stopped, and the compressed air from the compressed air source 7 is not discharged (flows out) from the inside of the pump 1. At this time, the pressure of the compressed air supplied to the pump 1 is higher than the pressure of the compressed air when the compressed air is flowing in the pump 1 (pressure within a predetermined pressure range). It is detected by the pressure detection device 4. Further, the air flow rate detecting device 5 detects that there is no flow of compressed air from the compressed air source 7 to the pump 1 (including the flow path in the pump 1). When the pressure oil supply / discharge system operates normally based on the detection results of the above three detection sensors 4, 5 and 6, the pressure oil supply / discharge system supplies pressure oil in a predetermined pressure range to the operating chamber 47 of the cylinder 10. It is detected that it is in a normal state.

When the operating state of the pressure oil supply / discharge system is detected by the hydraulic pressure detection sensor 6 and the air flow rate detection sensor 5 among the three detection sensors 4, 5 and 6 provided in the pressure oil supply / discharge system, the detection thereof. As shown in Table 1 below, there are a total of four combinations of results.

The conventional pressure oil supply / discharge system does not have an air flow rate detection sensor and an air pressure detection sensor, but has only a hydraulic pressure detection switch. Therefore, it is detected by the hydraulic pressure detection switch that the pressure of the pressure oil discharged from the pressure oil supply / discharge system to the cylinder exceeds a predetermined pressure. Based on the detection result, it was judged that the pressure oil supply / discharge system was in a normal state. Further, it was determined that the pressure oil supply / discharge system was in an abnormal state because the hydraulic pressure detection switch detected that the pressure was lower than the predetermined pressure. The conventional pressure oil supply / discharge system is excellent in that it can confirm that the pressure oil of an appropriate pressure is supplied to the cylinder. However, even when the pressure oil supply / discharge system supplies pressure oil at an appropriate pressure to the cylinder, it may be in an abnormal state in which components such as pumps or peripheral equipment are excessively driven, or the peripheral equipment may be worn out. It may be in an abnormal state when it is used with slight damage. The conventional pressure oil supply / discharge system cannot detect such an abnormal state. If it is used for a long period of time in the abnormal state, it may stop deterioration over time and lead to major damage. In the pressure oil supply / discharge system of the present embodiment, the above-mentioned state (the state of (2) in Table 1 or the state of (1) -2 in Table 2) or such a state is obtained. The state where there is a problem (including the possibility of a problem) is also regarded as an abnormal state of the pressure oil supply / discharge system. The abnormal state is detected by combining the detection result of the air flow rate detection sensor 5 and the detection result of the hydraulic pressure detection sensor 6.

In the pressure oil supply / discharge system of the present embodiment, first, pressure oil supply is performed by combining the detection results of the two detection sensors of the hydraulic pressure detection sensor 6 and the air flow rate detection sensor 5 among the above three detection sensors 4, 5 and 6. Judge the abnormal / normal state of the discharge system.

In (1) in Table 1, the hydraulic pressure detection sensor 6 detects that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is within a predetermined pressure range. Further, the air flow rate detection sensor 5 detects that the compressed air does not flow in the flow path connecting the compressed air source 7 and the pump 1. By combining the detection result of the hydraulic pressure detection sensor 6 and the detection result of the air flow rate detection sensor 5, it can be seen that the pressure oil supply / discharge system is in a normal state.

In (2) in Table 1, the hydraulic pressure detection sensor 6 detects that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is within a predetermined pressure range. Further, the air flow rate detection sensor 5 detects that compressed air is flowing in the flow path connecting the compressed air source 7 and the pump 1. Here, in the conventional pressure oil detection system having only the hydraulic pressure detection switch, it is determined to be a normal state from the detection result of the hydraulic pressure detection switch. However, in the pressure oil supply / discharge system of the present embodiment, it can be seen that the pressure oil supply / discharge system is in an abnormal state by combining the detection result of the hydraulic pressure detection sensor 6 and the detection result of the air flow rate detection sensor 5. When such a detection result is obtained, in the pressure oil supply / discharge system, the pressure oil is slowly discharged from the three-way valve 2, the pressure guarantee valve 3, the piping, etc. to the oil tank 9 or to the outside (to maintain a predetermined pressure range). It is presumed that the pump 1 is being driven little by little due to leakage. Alternatively, the pressure oil supply / discharge system supplies compressed air having a pressure higher than the desired pressure to the pump 1 due to a failure of the pressure regulator 8 or a poor pressure adjustment of the pressure regulator 8, and the pump 1 is gradually driven. It is presumed that it is in a state such as being. If such a state is for a short period of time, it is unlikely that it will immediately lead to wear or failure of the components of the oil supply / drainage system, but if such a state continues for a long period of time, it may lead to wear or failure of the components. There is. Therefore, it is determined that the pressure oil supply / discharge system is in an abnormal state because it is or may be defective.

In (3) and (4) in Table 1 above, it is hydraulic pressure that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is outside the predetermined pressure range (higher or lower than the predetermined pressure range). It is detected by the detection sensor 6. Further, in (3) in Table 1, it is detected by the air flow rate detection sensor 5 that the compressed air does not flow in the flow path connecting the compressed air source 7 and the pump 1. In (4) in Table 1, the air flow rate detection sensor 5 detects that compressed air is flowing in the flow path connecting the compressed air source 7 and the pump 1. In this case, both the conventional pressure oil detection system having only the oil pressure detection switch described above and the pressure oil supply / discharge system of the present embodiment are determined to be in an abnormal state from the detection result of the oil pressure detection sensor 6. However, in the pressure oil supply / discharge system of the present embodiment, there is a difference in the detection result of the air flow rate detection sensor 5, that is, an abnormal state when compressed air is not flowing in the flow path ((3) in Table 1 above). , The estimated abnormal state of the compressed oil supply / discharge system is different from the abnormal state when flowing ((4) in Table 1 above). First, in (3) in Table 1, the following abnormal states can be considered. It is presumed that some external force acts on the output rod of the cylinder 10 to increase the pressure in the flow path of the pressure oil. Alternatively, it is presumed that the temperature of the pressure oil rises, the pressure oil in the flow path thermally expands, and the pressure in the flow path rises. Alternatively, it is presumed that the pump 1 cannot operate normally due to a failure or improper adjustment of the compressed air source 7 or the pressure regulator 8, and the pressure in the flow path of the pressure oil is below the predetermined pressure range. ..

Next, in (4) in Table 1 above, the following abnormal state different from (3) is presumed. It is presumed that the pressure oil leaks from the three-way valve 2 and the pressure guarantee valve 3 and the pump 1 is being driven little by little. Alternatively, in a state where high-pressure compressed air is supplied due to a failure of the compressed air source 7 or the pressure regulator 8, the pump 1 is moving little by little, and the pressure in the flow path of the pressure oil exceeds a predetermined pressure range. It is presumed that there is.

In the conventional pressure oil supply / discharge system equipped with only the hydraulic pressure detection switch, it was not possible to isolate and estimate the abnormal state in detail. On the other hand, in the pressure oil supply / discharge system of the present embodiment including the hydraulic pressure detection sensor 6 and the air flow rate detection sensor 5, the detection result of the hydraulic pressure detection sensor 6 and the detection result of the air flow rate detection sensor 5 are combined. It is possible to infer the abnormal state of the hydraulic oil supply / discharge system according to the combination result.

Further, by providing the air pressure detection sensor 4 in addition to the above two detection sensors 5 and 6, the following states of the pressure oil supply / discharge system are detected.

In (1) -1 in Table 2 above, the hydraulic pressure detection sensor 6 detects that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is within a predetermined pressure range. Further, the air flow rate detection sensor 5 detects that the compressed air does not flow in the flow path connecting the compressed air source 7 and the pump 1. Further, the air pressure detection sensor 4 detects that the pressure of the compressed air in the flow path connecting the compressed air source 7 and the pump 1 is within a predetermined pressure range. By combining the detection result of the oil pressure detection sensor 6, the detection result of the air flow rate detection sensor 5, and the detection result of the air pressure detection sensor 4, it can be seen that the pressure oil supply / discharge system is in a normal state.

In (1) -2 in Table 2 above, the hydraulic pressure detection sensor 6 detects that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is within a predetermined pressure range. Further, the air flow rate detection sensor 5 detects that the compressed air does not flow in the flow path connecting the compressed air source 7 and the pump 1. Further, the air pressure detection sensor 4 detects that the pressure of the compressed air in the flow path connecting the compressed air source 7 and the pump 1 is out of the predetermined pressure range. Here, in the pressure oil detection system having two detection sensors 5 and 6, the state of (1) -2 in Table 2 above is normal from the detection result of the hydraulic pressure detection sensor 6 and the detection result of the air flow rate detection sensor 5. It was judged to be in a state. However, in the pressure oil supply / discharge system of the present embodiment, the pressure oil supply / discharge system becomes abnormal by combining the detection result of the oil pressure detection sensor 6, the detection result of the air flow rate detection sensor 5, and the detection result of the air pressure detection sensor 4. It turns out that it is in a state. When such a detection result is obtained, the compressed oil supply / discharge system supplies compressed oil within a predetermined pressure range to the cylinder 10, and then compresses due to loosening of the joint, deterioration, wear, breakage, etc. of the piping and the pump 1. It is presumed that compressed air has escaped from the flow path (including the flow path in the pump) connecting the air source 7 and the pump 1. If such a state is for a short period of time, it is unlikely that it will immediately lead to wear or failure of the components of the oil supply / drainage system, but if such a state continues for a long period of time, it will lead to wear or failure of the components. There is. Therefore, it is determined that the pressure oil supply / discharge system is in an abnormal state because it is or may be defective.

In (2) -1 in Table 2 above, the hydraulic pressure detection sensor 6 detects that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is within a predetermined pressure range. Further, the air flow rate detection sensor 5 detects that compressed air is flowing in the flow path connecting the compressed air source 7 and the pump 1. Further, the air pressure detection sensor 4 detects that the pressure of the compressed air in the flow path connecting the compressed air source 7 and the pump 1 is within a predetermined pressure range. By combining the detection result of the hydraulic pressure detection sensor 6, the detection result of the air flow rate detection sensor 5, and the detection result of the air pressure detection sensor 4, it can be seen that the pressure oil supply / discharge system is in an abnormal state. When such a detection result is obtained, in the pressure oil supply / discharge system, the pressure oil is slowly discharged from the three-way valve 2, the pressure guarantee valve 3, the piping, etc. to the oil tank 9 or to the outside (to maintain a predetermined pressure range). It is presumed that the pump 1 is being driven little by little due to leakage.

In (2) -2 in Table 2 above, the hydraulic pressure detection sensor 6 detects that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is within a predetermined pressure range. Further, the air flow rate detection sensor 5 detects that compressed air is flowing in the flow path connecting the compressed air source 7 and the pump 1. Further, the air pressure detection sensor 4 detects that the pressure of the compressed air in the flow path connecting the compressed air source 7 and the pump 1 is out of the predetermined pressure range. By combining the detection result of the oil pressure detection sensor 6, the detection result of the air flow rate detection sensor 5, and the detection result of the air pressure detection sensor 4, it can be seen that the pressure oil supply / discharge system is in an abnormal state. When such a detection result is obtained, the pressure oil supply / discharge system pumps compressed air having a pressure higher than the desired pressure due to a failure of the compressed air source 7 or the pressure regulator 8 or a poor pressure adjustment of the pressure regulator 8. It is presumed that the pump 1 is being supplied to 1 and the pump 1 is being driven little by little.

In (3) -1 in Table 2 above, it is hydraulically detected that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is outside the predetermined pressure range (higher or lower than the predetermined pressure range). It is detected by the sensor 6. Further, the air flow rate detection sensor 5 detects that the compressed air does not flow in the flow path connecting the compressed air source 7 and the pump 1. Further, the air pressure detection sensor 4 detects that the pressure of the compressed air in the flow path connecting the compressed air source 7 and the pump 1 is within a predetermined pressure range. By combining the detection result of the oil pressure detection sensor 6, the detection result of the air flow rate detection sensor 5, and the detection result of the air pressure detection sensor 4, it can be seen that the pressure oil supply / discharge system is in an abnormal state. When such a detection result is obtained, it is presumed that the pressure oil supply / discharge system is in a state in which some external force acts on the output rod of the cylinder 10 to increase the pressure in the pressure oil flow path. .. Alternatively, it is presumed that the temperature of the pressure oil rises, the pressure oil in the flow path thermally expands, and the pressure in the flow path rises.

In (3) -2 in Table 2 above, it is hydraulically detected that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is outside the predetermined pressure range (higher or lower than the predetermined pressure range). It is detected by the sensor 6. Further, the air flow rate detection sensor 5 detects that the compressed air does not flow in the flow path connecting the compressed air source 7 and the pump 1. Further, the air pressure detection sensor 4 detects that the pressure of the compressed air in the flow path connecting the compressed air source 7 and the pump 1 is out of the predetermined pressure range. By combining the detection result of the oil pressure detection sensor 6, the detection result of the air flow rate detection sensor 5, and the detection result of the air pressure detection sensor 4, it can be seen that the pressure oil supply / discharge system is in an abnormal state. When such a detection result is obtained, the pressure oil supply / discharge system pumps compressed air having a pressure lower than the desired pressure due to a failure of the contracted air source 7 or the pressure regulator 8 or a poor pressure adjustment of the pressure regulator 8. It is presumed that the pump 1 is being supplied to 1 and the pump 1 is not operating normally.

In (4) -1 in Table 2 above, it is hydraulically detected that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is outside the predetermined pressure range (higher or lower than the predetermined pressure range). It is detected by the sensor 6. Further, the air flow rate detection sensor 5 detects that compressed air is flowing in the flow path connecting the compressed air source 7 and the pump 1. Further, the air pressure detection sensor 4 detects that the pressure of the compressed air in the flow path connecting the compressed air source 7 and the pump 1 is within a predetermined pressure range. By combining the detection result of the oil pressure detection sensor 6, the detection result of the air flow rate detection sensor 5, and the detection result of the air pressure detection sensor 4, it can be seen that the pressure oil supply / discharge system is in an abnormal state. When such a detection result is obtained, it is presumed that the pressure oil supply / discharge system is in a state where pressure oil leaks from the three-way valve 2 and the pressure guarantee valve 3 and the pump 1 is gradually driven. ..

In (4) -2 in Table 2 above, it is hydraulically detected that the pressure of the pressure oil in the flow path connecting the three-way valve 2 and the cylinder 10 is outside the predetermined pressure range (higher or lower than the predetermined pressure range). It is detected by the sensor 6. Further, the air flow rate detection sensor 5 detects that compressed air is flowing in the flow path connecting the compressed air source 7 and the pump 1. Further, the air pressure detection sensor 4 detects that the pressure of the compressed air in the flow path connecting the compressed air source 7 and the pump 1 is out of the predetermined pressure range. By combining the detection result of the oil pressure detection sensor 6, the detection result of the air flow rate detection sensor 5, and the detection result of the air pressure detection sensor 4, it can be seen that the pressure oil supply / discharge system is in an abnormal state. When such a detection result is obtained, in the pressure oil supply / discharge system, high-pressure compressed air is supplied due to a failure of the compressed air source 7 or the pressure regulator 8, and the pump 1 is gradually moving to flow the pressure oil. It is presumed that the pressure in the path exceeds the predetermined pressure range.

In the above-mentioned pressure oil supply / discharge system, lamps 75, 76, and 77 are connected to the three detection sensors 4, 5, and 6, respectively. The lamp 77 turns on when the hydraulic pressure detection sensor 6 detects that the pressure of the pressure oil in the flow path is within the predetermined pressure range, and turns off when the pressure is higher or lower than the predetermined range. When the air flow rate detection sensor 5 detects that compressed air is not flowing in the flow path (including the flow path in the pump 1) connecting the compressed air source 7 and the pump 1, the lamp 76 lights up and flows. Turns off when it is detected. The lamp 75 lights up when the air pressure detection sensor 4 detects that the pressure of the compressed air in the flow path is within the predetermined pressure range, and turns off when it detects that the pressure is lower or higher than the predetermined pressure range. .. The operator can confirm that the pressure oil supply / discharge system is in a normal state by turning on the three lamps 75, 76, 77. Further, when any one of the three lamps 75, 76, and 77 is turned off, the operator can confirm that the pressure oil supply / discharge system is in an abnormal state.

The above embodiment has the following advantages.
In the conventional pressure oil supply / discharge system and the pressure oil supply / discharge system of the first embodiment, the detection results of the three detection sensors 4, 5 and 6 are combined even in the state determined to be the normal state. It is possible to detect that the pressure oil supply / discharge system is in an abnormal state. Further, compared to the estimated abnormal state in the conventional pressure oil supply / discharge system and the pressure oil supply / discharge system of the first embodiment, the estimated abnormal state of the pressure oil supply / discharge system of the present embodiment is more detailed. Since it is divided into various events, it is easy for workers who perform repairs and maintenance to identify defective parts.

FIG. 4 shows a second embodiment of the present invention. In this second embodiment, the same members (or similar members) as the constituent members of the first embodiment will be described with the same reference figures in principle.

The pressure oil supply / discharge system of the second embodiment of the present invention includes a control device 80.
The control device 80 is connected to the air pressure detection sensor 4, the air flow rate detection sensor 5, and the hydraulic pressure detection sensor 6 by an electric signal line or the like, and can receive electric signals from the sensors 4, 5, and 6. The control device 80 is in a normal state (within a predetermined pressure range or no compressed air is flowing) or an abnormal state (out of a predetermined pressure range or with compressed air flowing) from each of the sensors 4, 5 and 6. Comparison between the storage unit 81 that receives and stores the information about the sensor, the calculation unit 82 that compares the information stored in advance in the storage unit 81, and the information by the signals from the sensors 4, 5 and 6, and the calculation unit 82. It has a display unit 83 and the like for displaying results and other information. It should be noted that the control device 80 of the present embodiment and the sensors 4, 5 and 6 are connected by radio waves such as radio waves instead of being connected by signal lines (wired) such as electricity and light. good.

The calculation unit 82 of the control device 80 compares the information about whether it is normal or abnormal received from the sensors 4, 5 and 6 with the information stored in advance in the storage unit 81, and based on the comparison result, The estimated abnormal state of the pressure oil supply / discharge system as shown in Table 2 above is displayed on the display unit 83. In addition, the method of dealing with the presumed abnormal state (maintenance method, repair location information, repair method) may be displayed on the display unit 83.

The pressure oil supply / discharge system of the present embodiment includes another hydraulic pressure detection sensor 85 and a liquid level detection sensor 86 in addition to the above three detection sensors 4, 5 and 6. The hydraulic pressure detection sensor 85 is provided in a flow path connecting the discharge port 18 of the pump 1 and the supply port 34 of the three-way valve 2, and detects the pressure of the oil pressure in the flow path. By comparing the detection results of the oil pressure detection sensor 85 and the oil pressure detection sensor 6, is there a problem in the pump 1 or is there a problem while connecting the three-way valve 2 and the pressure guarantee valve 3 to the cylinder 10. Can be detected. Further, the liquid level detection sensor 86 is provided in the oil tank 9 and detects the liquid level height of the oil in the oil tank 9. When it is detected by other detection sensors 4, 5 and 6 that the oil is leaking from the three-way valve 2, the pressure guarantee valve 3, the piping, etc., whether the leaked oil is returned to the oil tank 9 or not to the outside. Whether it is leaked can be detected from the detection result of the liquid level detection sensor 86. These detection sensors 85 and 86 are electrically connected to the control device 80, and the control device 80 receives the detection result of the detection sensors 85 and 86 as a signal such as an electric signal.

The pressure oil supply / discharge system of the second embodiment may be mounted on an injection molding machine, a press device, a machine tool, or the like. In this case, the pressure oil supply / discharge system of the present embodiment supplies pressure oil to the cylinder 10 or the like constituting the clamp device for fixing the mold or the work. In the cylinder 10 of the clamp device, after the control device determines from the detection results of the air pressure detection sensor 4, the air flow rate detection sensor 5, and the hydraulic pressure detection sensor 6 that the pressure oil supply / discharge system is in a normal state, the cylinder 10 An external force in the retracting direction may act on the output rod. For example, in a clamping device for fixing a mold such as an injection molding machine, an external force (mold opening force) may act on the clamping device when the mold is opened. In this case, the control device can calculate the magnitude of the external force, and the procedure is as follows.

First, the detection pressure information (pressure value) of the hydraulic pressure detection sensor 6 in the normal state of the pressure oil supply / discharge system (the state shown in (1) -1 of Table 2 above) is transmitted to the control device 80. The detected pressure information is stored in the storage unit 81 as reference pressure information. The information acquisition time and temperature information may be stored together with the detected pressure information. Next, when an external force acts on the output rod of the cylinder 10 in the retracting direction, the pressure in the working chamber 47 and the flow path of the cylinder 10 increases. When the detected pressure exceeds a predetermined pressure range, the pressure oil supply / discharge system becomes an abnormal state (for example, the state of (3) -1 in Table 2 above). The detection pressure information and the like of the hydraulic pressure detection sensor 6 are transmitted to the control device 80 at predetermined intervals, and are stored in the storage unit 81 each time. The storage unit 81 stores the calculated external force information calculated from the pressure of the operating chamber 47 (considering the cross-sectional area ratio of the piston and the output rod). The calculation unit 82 compares the detected pressure information with the calculated external force information, selects the calculated external force information corresponding to the detected pressure, and displays the selected information on the display unit 83. As a result, the worker can know the calculated magnitude of the external force. Here, instead of the calculation unit 82 sending the calculated external force information to the display unit 83 and displaying it on the display unit 83, the calculation unit 82 sends the calculated external force information to the control device such as the injection molding machine, and the control device thereof. It may be displayed on the display unit of, or it may be sent to another terminal device for display. The calculated external force information is a measured value in which the pressure of the pressure oil in the flow path according to the magnitude of the external force is measured in advance, for example, instead of the information calculated from the pressure of the operating chamber 47. May be.

Each of the above embodiments can be modified as follows.
Instead of the pressure oil supply / discharge system of the second embodiment provided with the control device 80, the control device provided in another system connected to the pressure oil supply / discharge system of the present embodiment is wirelessly or wired. It may be connected electrically.
Instead of or in addition to the above detection sensor, a temperature detection sensor for detecting the temperature of pressure oil or the like, a vibration detection sensor for detecting vibration of the pump or the like may be provided.
The air flow rate detection sensor 5 may be provided in the pump 1 or in the air discharge hole 13 of the pump 1 instead of being provided in the flow path connecting the compressed air source 7 and the pump 1.
Of course, various changes can be made to the extent that a person skilled in the art can infer.

1: Pump, 2: Three-way valve, 3: Pressure guarantee valve, 4: Air pressure detection sensor (air pressure detection device), 5: Air flow rate detection sensor (air flow rate detection device), 6: Hydraulic pressure detection sensor (hydraulic pressure detection device) ), 10: Cylinder (hydraulic oil supply / discharge object), 80: Control device.

Claims (4)

A pump (1) that is driven by the supply of compressed air and that supplies pressure oil to the pressure oil supply / discharge target (10), and a pump (1).
The pressure oil is provided in the middle of the flow path for supplying and discharging the pressure oil to the pressure oil supply / discharge target (10), and the pressure oil is supplied from the pump (1) to the pressure oil supply / discharge target (10). A three-way valve (2) that switches between the state and the state in which the pressure oil is discharged to the outside from the pressure oil supply / discharge object (10).
A pressure guarantee valve (3) that discharges the pressure oil to the outside so that the pressure of the pressure oil in the flow path falls below the predetermined pressure when the pressure of the pressure oil in the flow path exceeds the predetermined pressure.
An air flow rate detecting device (5) that detects the flow rate of compressed air supplied to or discharged from the pump (1), and
A hydraulic pressure detecting device (6) for detecting the pressure of the pressure oil in the flow path is provided.
A pressure oil supply / discharge system characterized by this. In the pressure oil supply / discharge system of claim 1,
A pressure oil supply / discharge system comprising an air pressure detecting device (4) for detecting the pressure of compressed air supplied to or discharged from the pump (1). In the pressure oil supply / discharge system of claim 1,
A control device (80) for detecting the state of the pressure oil supply / discharge system by receiving a signal from the air flow rate detection device (5) and the hydraulic pressure detection device (6) is provided.
A pressure oil supply / discharge system characterized by this. In the pressure oil supply / discharge system of claim 2,
A control device (80) for detecting the state of the pressure oil supply / discharge system by receiving signals from the air pressure detection device (4), the air flow rate detection device (5), and the hydraulic pressure detection device (6) is provided.
A pressure oil supply / discharge system characterized by this.

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