JP6260852B2 - Hydraulic cylinder circuit leak detection device - Google Patents

Description

  The present invention relates to a leak detection apparatus for a hydraulic cylinder circuit, and more particularly to an apparatus for detecting an oil leak in a hydraulic cylinder circuit that operates by supplying and discharging hydraulic pressure oil from a hydraulic source.

  The conventional technology consists of a hydraulic servo system composed of an actuator and a servo valve, and a hydraulic pump that supplies pressure oil to the hydraulic servo system. The hydraulic pump is in an on-load state depending on the operating status of the hydraulic servo system. Alternatively, in a hydraulic circuit having an unloading valve for switching to an unloading state, a device that detects leakage of the hydraulic cylinder circuit based on the flow rate of hydraulic oil supplied to the hydraulic servo system based on the ratio of the onload time of the hydraulic pump. Yes (see, for example, Patent Document 1).

JP 2004-212128 A

  Since the above-described conventional technology is a device that detects a leak in the hydraulic cylinder circuit based on the flow rate of hydraulic oil supplied to the hydraulic servo system based on the ratio of the on-load time of the hydraulic pump, a leak occurs in the hydraulic circuit. Even then, the leak cannot be detected until the on-load time of the hydraulic pump ends. In addition, there is a drawback that the location cannot be specified even if a leak is detected.

  The present invention has been made in view of the above-described problems, and can detect when a hydraulic cylinder circuit leaks, and can detect where the leak has occurred. An object is to provide an apparatus.

The leak detection device for a hydraulic cylinder circuit according to the present invention includes a cylinder body, a piston slidably fitted into the cylinder body, a first pressure chamber on a cap side defined by the piston in the cylinder body, and a rod side A hydraulic cylinder having a second pressure chamber and an output rod fixed to the piston and connected to the actuated device through the second pressure chamber; and an output rod of the hydraulic cylinder, A speed / position detector that detects the moving speed of the rod or the position at every moment, a first supply / discharge circuit connected to the first pressure chamber, and a second supply / discharge circuit connected to the second pressure chamber. A hydraulic source having a hydraulic pump connected to an oil tank, an oil tank and a hydraulic pump of the hydraulic source connected to the upstream side thereof, and connected to the first supply / discharge circuit; Circuit and front The second circuit in the unit connected to the second supply / exhaust circuit is provided in one of the direction switching valve connected to the downstream side thereof, the first circuit in the unit or the second circuit in the unit, and the flow rate of the circuit or A hydraulic unit comprising a flow rate / flow rate detector for detecting a flow rate, a pressure compensation flow rate control valve for controlling the flow rate in the supply / discharge direction of the circuit, and the flow rate / flow rate detector And a monitoring device for identifying a leak and a leak circuit based on the output fluctuation pattern and the output fluctuation pattern of the speed / position detector.

The leak detection device for a hydraulic cylinder circuit according to the present invention includes a cylinder body, a piston slidably fitted into the cylinder body, a first pressure chamber on a cap side defined by the piston in the cylinder body, and a rod side A second pressure chamber and an output rod fixed to the piston and connected to the operated device through the second pressure chamber, and the load of the operated device is connected to the first via the output rod. A hydraulic cylinder that acts on the pressure chamber or the second pressure chamber, a speed / position detector that detects the moving speed or the momentary position of the output rod, and a first supply / discharge circuit connected to the first pressure chamber; A second supply / exhaust circuit connected to the second pressure chamber;
A hydraulic source having a hydraulic pump connected to the oil tank; an oil tank and a hydraulic pump of the hydraulic source connected to the upstream side thereof; and the first circuit in the unit connected to the first supply / discharge circuit and the second supply A second circuit in the unit connected to the exhaust circuit is provided on the downstream side of the direction switching valve connected to the downstream side thereof, and the first circuit in the unit corresponding to the operating position of the direction switching valve. And a pilot check valve that opens and closes the second circuit in the unit, and is provided in one of the first circuit in the unit or the second circuit in the unit downstream of the pilot check valve. A flow rate / flow rate detector to detect, a pressure control flow rate control valve with pressure compensation for controlling the flow rate of the circuit, a hydraulic unit, an output of the flow rate / flow rate detector, and the speed / flow rate Place A monitoring device for identifying a leak and leak location based on the pattern of the output fluctuation of the detector, characterized by comprising a.

In the present invention described above, the amount of oil supplied to one pressure chamber of the hydraulic cylinder is controlled by a flow control valve with pressure compensation, and the moving speed or the momentary position of the output rod of this hydraulic cylinder is detected by a speed / position detector. Since the flow rate / flow rate detector detects the amount of oil supplied to the other pressure chamber, and the leak circuit is specified based on the output fluctuation pattern of the speed / position detector and the flow rate / flow rate detector. This has the effect of specifying the leak circuit simultaneously with the start of the leak of the circuit.

  The hydraulic cylinder circuit leakage detection device of the present invention controls the amount of oil supplied to one pressure chamber of a hydraulic cylinder on which a load of an actuated device acts by a flow control valve with pressure compensation. The velocity is detected by the velocity / position detector, and the flow rate supplied to the other pressure chamber where the load of the operated device does not act is detected by the flow velocity / flow detector, and the velocity / position detector and the flow velocity / flow detector are detected. Since the leakage circuit is specified based on the output fluctuation pattern of the circuit, the leakage circuit is specified simultaneously with the start of the circuit leakage, and the flow rate / flow rate detector when the pilot check valve blocks the circuit in the unit and the This has the effect of identifying internal leakage of the hydraulic cylinder based on the output fluctuation pattern of the speed / position detector signal.

1 is a hydraulic cylinder circuit diagram showing an embodiment of the present invention. The circuit diagram which shows a pilot check valve part. The circuit diagram of a flow control valve with meter-in side pressure compensation. The block diagram of a monitoring apparatus. It is a figure which shows the fluctuation pattern of the output signal EV and the output signal FQ in the neutral position of a direction switching valve, Comprising: (a) is normal, (b) is at the time of the leak of the 1st supply / exhaust circuit of a cap side, (c ) Shows when a leak occurs in the second supply / exhaust circuit on the rod side, and (d) shows when an internal leak occurs in the hydraulic cylinder. It is a figure which shows the fluctuation pattern of the output signal EV and the output signal FQ in the right switching position of a direction switching valve, Comprising: (a) is normal, (b) is at the time of the leak generation | occurrence | production of the 1st supply / exhaust circuit on a cap side, c) shows the occurrence of leakage in the second supply / exhaust circuit on the rod side. It is a figure which shows the fluctuation pattern of the output signal EV in the left switching position of a direction switching valve, and the output signal FQ, Comprising: (a) is normal, (b) is the time of the leak generation | occurrence | production of the 1st supply / exhaust circuit by the side of a cap, c) shows the occurrence of leakage in the second supply / exhaust circuit on the rod side.

  An embodiment of the present invention will be described with reference to FIG. In FIG. 1, a hydraulic cylinder circuit 10 includes an operating unit 20 including a hydraulic cylinder 21, a hydraulic source 51, a direction switching valve 42 connected to the hydraulic source 51, and a pilot provided downstream of the direction switching valve 42. The hydraulic pressure unit 40 includes a check valve unit 43, a flow velocity / flow rate detector 48, and a pressure compensated flow rate control valve 46.

  Applications in which the hydraulic cylinder circuit 10 is used will be described. The hydraulic cylinder circuit 10 is used for a movable weir provided to control the amount of overturning of the overturning weir provided across the river and to use the water resources of the river. Specifically, the operating unit 20 is provided in a overturning weir whose hydraulic cylinder 21 constitutes a movable weir, and hydraulic oil from the hydraulic unit 40 is supplied to and discharged from the hydraulic cylinder 21 of the operating unit 20. The amount of weir overturning is controlled.

  The movable weir described above includes an operating unit 20 having a hydraulic cylinder 21 that operates a plurality of overturning weirs provided across a river, and a hydraulic unit 40 that controls supply and discharge of hydraulic oil to the hydraulic cylinder 21 of the operating unit 20. In order to control the water resources of the river, the amount of overturning of the overturning weir is controlled while monitoring the state of the river, and its operation is extremely slow. Become.

  In this way, the device with nature, particularly when a leak occurs in the hydraulic cylinder circuit 10, will cause the hydraulic oil to spill into the river as soon as possible and if it does not detect where it has leaked, The problem of contaminating occurs.

  The operating unit 20 of the hydraulic cylinder circuit 10 used in the above-described application includes a hydraulic cylinder 21 provided with an output rod 24 that operates the operated device 30 (falling weir), and a cap-side pressure chamber of the hydraulic cylinder 21. A first supply / exhaust circuit 31 on the cap side that supplies and discharges the operating pressure oil to and from the first pressure chamber 25 and the second pressure chamber 26 of the rod side pressure chamber, a second supply / exhaust circuit 32 on the rod side, and a hydraulic cylinder 21 A speed / position detector 28 for detecting the moving speed or moving position of the output rod 24 is used.

  The hydraulic cylinder 21 has a piston 23 that is slidably fitted into the cylinder body 22 and to which the output rod 24 is fixed. The first pressure chamber 25 that is a cap-side pressure chamber is formed by the piston 23 and the cylinder body 22. And the second pressure chamber 26 of the rod side pressure chamber is formed, and the output rod 24 penetrates the second pressure chamber.

  The output rod 24 of the hydraulic cylinder 21 has an actuated device 30 (falling weir) connected to the tip of the output rod 24, and is operated by the operating force of the hydraulic oil supplied to and discharged from the first pressure chamber 25 and the second pressure chamber 26 of the hydraulic cylinder 21. Operate the actuated device 30.

  The first supply / discharge circuit 31 on the cap side of the hydraulic cylinder 21 supplies / discharges hydraulic oil to / from the first pressure chamber 25 of the cap side pressure chamber, and the second supply / discharge circuit 32 on the rod side supplies the first pressure chamber 25 of the rod side pressure chamber. 2 is a circuit for supplying and discharging hydraulic oil to and from the pressure chamber 26, and the first supply / discharge circuit 31 on the cap side and the second supply / discharge circuit 32 on the rod side connect the hydraulic unit 40 and the hydraulic cylinder 21. It becomes long because it crosses the river or crosses the river.

A speed / position detector 28 provided on the output rod 24 of the hydraulic cylinder 21 and measuring the moving speed or moving amount thereof is provided on the main body 28a and has a roller 28b pressed against the surface of the output rod 24. The rotation of the roller 28b is transmitted to an encoder (not shown), and the moving speed or the position of the output rod 24 is detected every moment .

  A hydraulic pressure source 51 having a hydraulic pump 52 provided in the hydraulic unit 40 and generating hydraulic pressure oil by sucking hydraulic oil from an oil tank 53 is a pressure control valve 54 provided on the discharge side of the hydraulic pump 52. The discharge pressure is controlled.

  The direction switching valve 42 connected to the discharge side of the hydraulic pump 52 and the oil tank 53 includes a first circuit 44 in the unit connected to the first supply / discharge circuit 31 on the cap side and a second supply / discharge on the rod side on the downstream side. An in-unit second circuit 45 connected to the circuit 32 is connected. The upstream side indicates the hydraulic power source 51 side, and the downstream side indicates the hydraulic cylinder 21 side.

  The direction switching valve 42 is configured to switch the direction switching valve 42 to the right switching position 42b or the left switching position 42c by applying an operation signal, and to turn the direction switching valve 42 when no operation signal is applied to the electromagnetic operation section. It is a structure provided with the spring which returns to the neutral position 42a.

The direction switching valve 42 configured as described above closes the discharge side of the hydraulic pump 52 of the hydraulic source 51 at the neutral position 42a. When operated to the right switching position 4 2 b, the hydraulic pump 52 is connected to the first intra-unit circuit 44 and the second intra-unit circuit 45 is connected to the oil tank 53. Further, when operated to the left switching position 4 2 c, the hydraulic pump 52 is connected to the second intra-unit circuit 45, and the first intra-unit circuit 44 is connected to the hydraulic tank 53.

  When the direction switching valve 42 is operated to the right switching position 42b, the hydraulic pressure oil of the hydraulic source 51 is supplied from the first circuit 44 in the unit to the cap side of the hydraulic cylinder 21 via the first supply / discharge circuit 31 on the cap side. The hydraulic oil supplied to the first pressure chamber 25 of the pressure chamber and in the second pressure chamber 26 of the rod side pressure chamber is transferred from the second supply / discharge circuit 32 on the rod side to the oil tank 53 via the second circuit 45 in the unit. It is the structure which returns.

  When the direction switching valve 42 is operated to the left switching position 42c, the hydraulic pressure oil of the hydraulic source 51 is supplied from the second circuit 45 in the unit to the rod of the hydraulic cylinder 21 via the second supply / discharge circuit 32 on the rod side. The hydraulic oil supplied to the second pressure chamber 26 of the side pressure chamber and the first pressure chamber 25 of the cap side pressure chamber flows from the first supply / discharge circuit 31 on the cap side through the first circuit 44 in the unit to the oil tank 53. It is the structure which returns to.

  Furthermore, when there is no operation signal of the direction switching valve 42 and the neutral position 42a is restored, the operating pressure oil of the hydraulic pump 52 is closed by the direction switching valve 42 and returned to the oil tank 53 via the pressure control valve 54. The discharge pressure of the pump 52 is controlled to the set pressure of the pressure control valve 54. The first intra-unit circuit 44 and the second intra-unit circuit 45 are communicated with the oil tank 53 via a pilot check valve portion 43 provided on the downstream side of the direction switching valve 42.

  The pilot check valve portion 43 provided on the downstream side of the direction switching valve 42 includes a cap side pilot check valve portion 43a for opening and closing the first circuit 44 in the unit, as shown in FIG. It is comprised with the rod side pilot check valve part 43b which opens and closes the 2nd circuit 45 in a unit.

  The cap side pilot check valve portion 43a of the pilot check valve portion 43 is composed of a check valve 43a1 for blocking the flow from the downstream side to the upstream side and a pilot 43a2 for opening the check valve 43a1. Further, the rod side pilot check valve portion 43b of the pilot check valve portion 43 is composed of a check valve 43b1 for blocking the flow from the downstream side to the upstream side and a pilot 43b2 for opening the check valve 43b1, The check valve 43a1 and the check valve 43b1 are opened by hydraulic pressure acting on the pilot 43a2 and the pilot 43b2.

  The pilot 43a2 of the pilot check valve portion 43 is connected to the in-unit second circuit 45, and the pilot 43b2 is connected to the in-unit first circuit 44.

  In the pilot check valve portion 43 having such a configuration, when the pilot check valve portion 43 is operated to the neutral position 42a, the first in-unit circuit 44 and the second in-unit circuit 45 are connected to the oil tank 53. Therefore, the check valve 43a1 and the check valve 43b1 block the first circuit 44 in the unit and the second circuit 45 in the unit.

However, when the direction switching valve 42 is operated to the right switching position 42b or the left switching position 42c, the hydraulic pressure acts on the first circuit 44 in the unit or the second circuit 45 in the unit, so the check valve 43a1 and the check valve The valve 43b1 is opened.

  That is, the pilot check valve unit 43 opens and closes the first intra-unit circuit 44 and the second intra-unit circuit 45 in conjunction with the operation position of the direction switching valve 42. Specifically, the flow from the downstream side to the upstream side of the first circuit 44 in the unit and the second circuit 45 in the unit is interrupted only when the direction switching valve 42 is in the neutral position 42a, and the flow is stopped at other switching positions. Operates to allow.

  The first circuit 44 in the unit connected to the first supply / exhaust circuit 31 on the cap side is provided with a flow velocity / flow rate detector 48 for measuring the flow rate or flow rate of the hydraulic oil passing through the first intra-unit circuit 44. The flow velocity / flow rate detector 48 has, for example, a configuration in which two oval gears that mesh and rotate in a circuit are provided, and the flow rate is measured based on the number of rotations of the two oval gears.

  Pressure compensated flow rate control that is provided in the second circuit 45 in the unit connected to the second supply / exhaust circuit 32 on the rod side and controls the upstream and downstream flow rates of the hydraulic fluid passing through the second circuit 45 in the unit. The valve 46 is configured to control the operating speed (operating position) of the hydraulic cylinder 21 because it controls the amount of oil supplied to and discharged from the second pressure chamber 26 of the rod-side pressure chamber of the hydraulic cylinder 21.

  The pressure compensation flow control valve 46 is a meter-in side pressure that controls the flow rate of hydraulic fluid flowing from the second circuit 45 in the unit into the second pressure chamber 26 of the hydraulic cylinder 21 via the second supply / discharge circuit 32 on the rod side. The flow rate control valve 46b with compensation and the flow rate of hydraulic fluid flowing out from the second circuit 45 in the unit from the second pressure chamber 26 of the rod side pressure chamber of the hydraulic cylinder 21 to the second supply / discharge circuit 32 on the rod side are controlled. And the meter-out side pressure compensation control valve 46a.

  As shown in FIG. 3, the meter-out side pressure compensation flow control valve 46a is applied with a flow control valve 46a1 operated to a required flow rate and a differential pressure before and after the flow control valve 46a1 is applied to the flow control valve 46a1. The pressure compensation valve 46a2 controls the differential pressure across the front and back to the set spring pressure, and the check valve 46a3 bypasses the flow rate control valve 46a1 and the pressure control valve 46a2.

  Since the check valve 46a3 blocks the bypass when the hydraulic oil flows through the second circuit 45 in the unit upstream in the meter-out side pressure compensation flow control valve 46a, It is controlled by a flow control valve 46a1 whose differential pressure is compensated by 46a2.

  Further, the meter-in side pressure compensation flow control valve 46b is applied with a flow control valve 46b1 operated to a required flow rate and a differential pressure before and after the flow control valve 46b1, and the differential pressure before and after the flow control valve 46b1 is set as a setting spring. The pressure compensation valve 46b2 controls the pressure, and the flow rate control valve 46b1 and the check valve 46b3 bypasses the pressure compensation valve 46b2.

  Since the check valve 46b3 shuts off the bypass when the hydraulic oil flows downstream in the unit second circuit 45, the meter-in side pressure compensation flow control valve 46b has a pressure compensation valve 46b2. Is controlled by the flow rate control valve 46b1 that compensates for the differential pressure across it.

  The meter-out side pressure compensated flow control valve 46a and the meter-in side pressure compensated flow control valve 46b provided in the second circuit 45 in the unit in this way are connected to the second pressure chamber 26 of the rod side pressure chamber of the hydraulic cylinder 21. Control the flow rate and flow rate of hydraulic pressure oil.

  That is, the meter-out side pressure compensation flow control valve 46a controls the operating speed of the output rod 24 of the hydraulic cylinder 21 in the descending direction 24a by the flow control function, and the meter-in side pressure compensation flow control valve 46b is hydraulic. The output rod 24 of the cylinder 21 controls the operating speed in the ascending direction 24b.

  Note that the flow rate control valve 46a1 and the flow rate control valve 46b1 may be either one if the speeds of the output rod 24 of the hydraulic cylinder 21 in the ascending direction 24a and the descending direction 24b are substantially the same. Since the configuration of the pressure compensation flow control valve 46 in this case is the configuration disclosed in FIG. 1 of Japanese Patent Laid-Open No. 11-280702, detailed description thereof is omitted.

  In FIG. 1 in which hydraulic pressure oil is generated by driving the hydraulic pump 52 of the hydraulic source 51, the hydraulic cylinder circuit 10 is configured such that the discharge side of the hydraulic pump 52 is in the neutral position 42 a without being operated. The pressure control valve 54 controls the discharge pressure to a constant value.

  In the neutral position 42a, the first in-unit circuit 44 and the second in-unit circuit 45 are communicated with the oil tank 53, so that the pilot check valve portion 43 has a cap side pilot check valve portion 43a and a rod side pilot check valve. Only the flow in the upstream direction of the portion 43b is blocked.

  In this way, the second pressure chamber 26 of the rod side pressure chamber in which the direction switching valve 42 is in the neutral position 42a and the flow to the upstream side is blocked by the pilot check valve portion 43 is held at that position. Since the pilot check valve unit 43 allows the flow to the downstream side, at the neutral position 42a, the oil tank is connected to the first pressure chamber 25 in the cap side pressure chamber and the second pressure chamber 26 in the rod side pressure chamber. 53 hydraulic oil is supplied.

  The hydraulic oil to the first pressure chamber 25 in the cap side pressure chamber is supplied from the first circuit 44 in the unit through the first supply / exhaust circuit 31 on the cap side, and the flow rate is detected by the flow velocity / flow rate detector 48. Is done.

  When the direction switching valve 42 is operated to the right switching position 42b, the first circuit 44 in the unit and the second circuit 45 in the unit are connected to the hydraulic pump 52 and the oil tank 53, so the first pressure chamber 25 of the cap side pressure chamber. Is supplied with working pressure oil, and the working oil in the second pressure chamber 26 of the rod side pressure chamber is discharged to the oil tank 53, so that the output rod 24 is actuated in the descending direction 24a with the actuated device 30. .

  The hydraulic fluid supplied to the first pressure chamber 25 in the cap side pressure chamber via the first circuit 44 in the unit and the first supply / exhaust circuit 31 in the cap side is a flow velocity / flow rate detector 48 of the first circuit 44 in the unit. The flow rate is detected by.

  The movement of the output rod 24 in the descending direction 24a becomes a speed at which the discharged hydraulic oil in the second pressure chamber 26 of the rod side pressure chamber is controlled by the meter-out side pressure compensated flow control valve 46a. The operating speed of the output rod 24 is detected by a speed / position detector 28.

  When the direction switching valve 42 is operated to the left switching position 42c, the second intra-unit circuit 45 and the first intra-unit circuit 44 are connected to the hydraulic pump 52 and the oil tank 53, so the second pressure chamber 26 of the rod side pressure chamber. The hydraulic pressure oil is supplied to the first pressure chamber 25 of the cap side pressure chamber, and the hydraulic oil is discharged to the oil tank 53, so that the output rod 24 operates in the ascending direction 24b along with the operated device 30.

  The flow rate of the hydraulic fluid supplied to the second pressure chamber 26 of the rod side pressure chamber via the second circuit 45 in the unit and the second supply / exhaust circuit 32 of the rod side is controlled by a flow rate control valve 46b with meter-in side pressure compensation. Value.

  The hydraulic oil in the first pressure chamber 25 of the cap side pressure chamber discharged by the hydraulic pressure oil supplied to the second pressure chamber 26 of the rod side pressure chamber is the first in the unit from the first supply / discharge circuit 31 on the cap side. Since the oil is discharged to the oil tank 53 via the circuit 44, the flow rate is detected by the flow velocity / flow rate detector 48.

  The movement of the output rod 24 in the ascending direction 24b is a speed at which the discharged hydraulic oil in the first pressure chamber 25 of the cap side pressure chamber is controlled by the meter-in side pressure compensation flow control valve 46b. The operating speed of the output rod 24 is measured by the speed / position detector 28.

  As shown in FIG. 4, the monitoring device 57 receives an output signal FQ that is a flow rate value measured by the flow velocity / flow rate detector 48 and an output signal EV that is the velocity of the output rod 24 measured by the speed / position detector 28. The input unit 57a, the analysis unit 57b that analyzes the signal from the input unit 57a, and the output unit 57c that outputs the signal from the analysis unit 57b as a leak occurrence signal.

  The analysis unit 57b has a pattern storing a pattern assuming leakage from the first supply / discharge circuit 31 on the cap side and a pattern assuming leakage from the second supply / discharge circuit 32 on the rod side. It consists of the part 32p and the pattern part 21p, and analyzes the signal applied to the input part 57a.

  The signal analyzed by the analysis unit 57b is transmitted to the control room that controls the hydraulic cylinder circuit 10 via the output unit 57c. The output unit 57c holds the signal until the failure (leakage) due to the signal from the analysis unit 57b is repaired, and sequentially outputs the signal when the signal changes sequentially.

  The pattern portion 31p shows a variation pattern of the output signal FQ and the output signal EV when leakage occurs in the first supply / discharge circuit 31 on the cap side when the direction switching valve 42 is in the neutral position 42a. Pattern 5b and a pattern 6b in FIG. 6 (b) showing a variation pattern of the output signal FQ and the output signal EV when a leak occurs in the first supply / discharge circuit 31 on the cap side when in the right switching position 42b. 7B, the pattern 7b in FIG. 7 (b) shows a variation pattern of the output signal FQ and the output signal EV when a leak occurs in the first supply / exhaust circuit 31 on the cap side at the left switching position 42c. .

  The pattern portion 32p shows a variation pattern of the output signal FQ and the output signal EV when a leak occurs in the second supply / discharge circuit 32 on the rod side when the direction switching valve 42 is in the neutral position 42a. Pattern 5c of FIG. 6 (c) showing the fluctuation pattern of the output signal FQ and the output signal EV when a leak occurs in the rod-side second supply / discharge circuit 32 when in the right switching position 42b. 7c is a pattern 7c shown in FIG. 7 (c) showing a variation pattern of the output signal FQ and the output signal EV when leakage occurs in the rod-side second supply / discharge circuit 32 when the switch is at the left switching position 42c. .

  When the direction switching valve 42 is in the neutral position 42a and the load of the actuated device 30 is acting on the output rod 24 in the descending direction 24a, the pattern portion 21p has an internal leakage in the hydraulic cylinder 21. The pattern 5d is used.

  The output signal EV shown in FIGS. 5A to 7C is “+” when the output rod 24 moves in the descending direction 24a and “−” when it moves in the ascending direction 24b. The output signal FQ is “+” when the flow of the first supply / exhaust circuit 31 on the cap side is the downstream flow 31a, and “−” is the upstream flow 31b. Moreover, the numerical value is attached for reference and is not related to the actual leakage amount.

  The output signals EV and FQ are “0” when the direction switching valve 42 is in the neutral position 42a, but are operated to the right switching position 42b and the left switching position 42c, and there is no leakage. Then, it is assumed that “+1” and “−1” respectively. This signal may be described as a reference value.

  5A to 5D show a state in which no leakage occurs in the cap-side first supply / exhaust circuit 31 and the rod-side second supply / exhaust circuit 32 at the neutral position 42a of the direction switching valve 42; An output signal EV in a state where a leak occurs only in the first supply / discharge circuit 31 on the cap side, a state where a leak occurs only in the second supply / discharge circuit 32 on the rod side, and a state where an internal leak occurs in the hydraulic cylinder 21 The pattern of the output signal FQ is shown.

  In the pattern 5a in the state where no leakage occurs in the first supply / exhaust circuit 31 on the cap side and the second supply / exhaust circuit 32 on the rod side shown in FIG. 5 (a), the direction switching valve 42 shuts off the hydraulic pressure source 51. In addition, since the pilot check valve portion 43 blocks the first intra-unit circuit 44 and the second intra-unit circuit 45, the output signal EV and the output signal FQ are composed of the curve 5a1 and the curve 5a2. .

  In the pattern 5b in the state where the leak occurs only at the cap-side first supply / discharge circuit 31 shown in FIG. 5B at time T1, the hydraulic oil in the cap-side first supply / discharge circuit 31 leaks. The signal FQ includes a curve 5b1 having a partial curve 5b11 that varies at time T1, and a curve 5b2 of the output signal EV that does not vary.

  The partial curve 5b11 in FIG. 5B is activated by the change in the flow rate of the hydraulic oil in the first supply / discharge circuit 31 on the cap side in FIG. 1, so the first supply / discharge circuit 31 on the cap side is short. When the capacity is not sufficient, an accumulator 56 may be installed on the upstream side of the flow velocity / flow rate detector 48 to detect the leakage of the first supply / discharge circuit 31 on the cap side more clearly.

  In the pattern 5c in which leakage occurs only at the rod side second supply / discharge circuit 32 shown in FIG. 5C at time T1, hydraulic oil in the rod side second supply / discharge circuit 32 leaks, and the output rod 24 changes in the descending direction 24a, the curve 5c2 having a partial curve 5c21 in which the output signal EV of the speed / position detector 28 fluctuates at time T1, and the time in the second supply / discharge circuit 32 on the rod side at time T1. It comprises a curve 5c1 having a partial curve 5c11 that fluctuates in the downstream flow 31a generated by the leakage of hydraulic oil.

  The pattern 5d in the state where the internal leakage of the hydraulic cylinder 21 shown in FIG. 5D has occurred at time T1 is the second pressure chamber 26 due to the load of the operated device 30 acting on the output rod 24 of the hydraulic cylinder 21. Since the output rod 24 changes in the descending direction 24a due to leakage from the first pressure chamber 25 to the first pressure chamber 25, a curve 5d2 having a partial curve 5d21 in which the output signal EV of the speed / position detector 28 fluctuates at time T1 is obtained. It is formed.

  Further, as the output rod 24 moves in the descending direction 24a, a curve having a partial curve 5d11 in which the output signal FQ fluctuates at time T1 by the amount of oil that the volume of the second pressure chamber 26 is insufficient by the amount of movement of the output rod 24. 5d1 is formed, and the curve 5d1 is composed of these two curves.

  The pattern 5c and the pattern 5d are similar, but the partial curve 5d11 is a variation corresponding to the volume of the output rod 24, whereas the partial curve 5c11 is a variation corresponding to the movement of the piston 23. Therefore, it becomes larger than the partial curve 5d11.

  6 (a) to 6 (c), the directional control valve 42 is operated to the right switching position 42b, the working pressure oil is supplied to the first pressure chamber 25 of the cap side pressure chamber, and the first of the rod side pressure chamber is changed. 2 Since the hydraulic oil in the pressure chamber 26 is discharged, the output rod 24 is leaked in the cap-side first supply / discharge circuit 31 and the rod-side second supply / discharge circuit 32 in a state of operating in the descending direction 24a. The patterns of the output signal EV and the output signal FQ in a state where no leakage occurs, in a state where leakage has occurred only in the first supply / discharge circuit 31 on the cap side, and in a state where leakage has occurred only in the second supply / discharge circuit 32 on the rod side. Yes.

  The pattern 6a in the state where no leakage occurs in the cap-side first supply / discharge circuit 31 and the rod-side second supply / discharge circuit 32 shown in FIG. 6A is activated by the operation to the right switching position 42b. Since the pressure oil flows in the downstream flow 31a and the output rod 24 moves in the descending direction 24a, the output signal EV and the output signal FQ fluctuate by the reference value +1, and are composed of the curves 6a1 and 6a2 that do not change thereafter. The

  The pattern 6b in the state where the leak has occurred only at the cap-side first supply / discharge circuit 31 shown in FIG. 6B at time T1, the hydraulic oil in the cap-side first supply / discharge circuit 31 leaks. The signal FQ includes a curve 6b1 having a partial curve 6b11 that varies in the + direction at time T1, and a curve 6b2 of the output signal EV that does not vary.

  The pattern 6c in the state in which leakage occurs only at the rod-side second supply / discharge circuit 32 shown in FIG. 6C at time T1 causes the hydraulic oil in the rod-side second supply / discharge circuit 32 to leak. The speed of the rod 24 in the descending direction 24 increases, the curve 6c2 having a partial curve 6c21 in which the output signal EV of the speed / position detector 28 fluctuates at time T1, and the second supply / discharge circuit 32 on the rod side at time T1. It becomes a curve 6c1 having a partial curve 6c11 that fluctuates in the downstream flow 31a generated by the leakage of the hydraulic oil inside.

  7 (a) to 7 (c), the directional control valve 42 is operated to the left switching position 42c, the working pressure oil is supplied to the second pressure chamber 26 of the rod side pressure chamber, and Since the hydraulic oil in the first pressure chamber 25 is discharged, the output rod 24 leaks in the cap-side first supply / discharge circuit 31 and the rod-side second supply / discharge circuit 32 in a state of operating in the upward direction 24b. The patterns of the output signal EV and the output signal FQ in a state where no leakage occurs, in a state where leakage has occurred only in the first supply / discharge circuit 31 on the cap side, and in a state where leakage has occurred only in the second supply / discharge circuit 32 on the rod side. Yes.

  The pattern 7a in the state where no leakage has occurred in the first supply / discharge circuit 31 on the cap side and the second supply / discharge circuit 32 on the rod side shown in FIG. 7A is activated by the operation to the left switching position 42c. Since the pressure oil flows in the upstream flow 31b and the output rod 24 moves in the upward direction 24b, the output signal EV and the output signal FQ fluctuate by the reference value −1, and thereafter, the curves 7a1 and 7a2 have no change. .

  In the pattern 7b in which leakage occurs only at the cap-side first supply / discharge circuit 31 shown in FIG. 7B at time T1, the hydraulic oil in the cap-side first supply / discharge circuit 31 leaks. The signal FQ includes a curve 7b1 having a partial curve 7b11 that varies in the + direction at time T1, and a curve 7b2 of the output signal EV that does not vary.

  The pattern 7c in the state where the leakage occurs only at the rod-side second supply / discharge circuit 32 shown in FIG. 7C at time T1 is because the hydraulic oil in the rod-side second supply / discharge circuit 32 leaks. The speed of the ascending direction 24b of the rod 24 decreases and the curve 7c2 having a partial curve 7c21 in which the output signal EV of the speed / position detector 28 fluctuates at time T1 and the second supply / discharge circuit 32 on the rod side at time T1. It becomes a curve 7c1 having a partial curve 7c11 that fluctuates in the upstream flow 31b generated by the leakage of the hydraulic oil inside.

  When the input unit 57a receives the output signal EV of the speed / position detector 28 of the hydraulic cylinder circuit 10 and the output signal FQ of the flow velocity / flow rate detector 48 of the hydraulic cylinder circuit 10, the monitoring device 57 applies this signal to the analysis unit 57b. If the applied signal does not vary, the analysis unit 57b determines that the operation is normal and does not give an output command to the output unit 57c. Therefore, it does not operate when the hydraulic cylinder circuit 10 is functioning normally.

  In a situation where the output signal EV and the output signal FQ are continuously output, if the signal of the output signal FQ fluctuates at time T1, the fluctuation of the signal is caused by the pattern portions 31p and the pattern portions 32p of the analysis unit 57b. If it is collated by the part 21p and matches any of the pattern 5b, pattern 6b, and pattern 7b of the pattern part 31p, the output part 57c is caused to transmit a leak signal of the first supply / discharge circuit 31 on the cap side.

  Similarly, in a situation where the output signal EV and the output signal FQ continue to be output at a constant level, if the signal of the output signal FQ and the output signal EV change at the same time at time T1, the change in the signal is caused by each pattern of the analysis unit 57b. The part 31p, the pattern part 32p, and the pattern part 21p are collated, and when they match the patterns 5c, 6c, and 7c of the pattern part 32p, the leakage signal of the second supply / discharge circuit 32 on the cap side is transmitted to the output part 57c. Let

  Further, in a situation where the output signal EV and the output signal FQ are continuously output, if the signal of the output signal FQ and the output signal EV change at the same time at time T1, the change in the signal is caused by each pattern portion of the analysis unit 57b. 31p, the pattern part 32p, and the pattern part 21p are collated, and by matching with the pattern 5d of the pattern part 21p, the internal leakage signal of the hydraulic cylinder 21 is transmitted to the output part 57c.

  Note that if a leak occurs at a different location in the hydraulic cylinder circuit 10, the monitoring device 57 sequentially transmits a leak signal in the order in which the fluctuation pattern of the signal matches the pattern portion of the analysis unit 57b. Therefore, when the leak signal of the first supply / discharge circuit 31 on the cap side continues, the leak signal of the second supply / discharge circuit 32 on the rod side may be transmitted.

  The transmission of the leak signal of the first supply / exhaust circuit 31 on the cap side is displayed on the central control room or the control panel of the hydraulic unit 40 or is notified by a warning sound. Oil leakage from the hydraulic cylinder circuit 10 causes environmental pollution, and if the circuit breaks up, the hydraulic cylinder 21 cannot be controlled, causing a secondary disaster. It is therefore desirable to detect and respond to leaks as soon as possible.

  The monitoring device 57 is configured to maintain a reset signal when a leak signal is transmitted in response to the first fluctuation of the output signal EV or the output signal FQ. If a leak occurs, a new leak signal may be generated.

  In the present invention, the first pressure chamber 25 of the cap-side pressure chamber of the hydraulic cylinder 21 is controlled by a flow control valve 46 with pressure compensation, and the second supply / discharge circuit 32 on the rod side is controlled by a speed / position detector for the hydraulic cylinder 21. 28, the cap side first supply / discharge circuit 31 connected to the first pressure chamber 25 of the cap side pressure chamber is monitored by the flow velocity / flow rate detector 48, and the cap side first supply / discharge circuit 31 is configured. The rod-side second supply / exhaust circuit 32 is connected through the piston 23 of the hydraulic cylinder 21 as a major feature.

  Therefore, leakage from the cap-side first supply / discharge circuit 31 is detected only by the flow velocity / flow rate detector 48, and leakage from the rod-side second supply / discharge circuit 32 is detected by the velocity / position detector 28 and the flow velocity. / Because it is detected by the simultaneous detection by the flow rate detector 48, the identification when a leak occurs can be made very clear.

  The embodiment of the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the scope of the idea of the present invention.

DESCRIPTION OF SYMBOLS 10 Hydraulic cylinder circuit 20 Actuating part 21 Hydraulic cylinder 22 Cylinder main body 23 Piston 24 Output rod 25 1st pressure chamber 26 2nd pressure chamber 28 Speed / position detector 30 Operated apparatus 31 1st supply / discharge circuit 32 2nd supply / discharge circuit 40 Hydraulic Unit 42 Directional Switching Valve 43 Pilot Check Valve 44 First In-Unit Circuit 45 Second In-Unit Circuit 46 Pressure Compensated Flow Control Valve 48 Flow Rate / Flow Detector 51 Hydraulic Source 52 Hydraulic Pump 53 Oil Tank 54 Pressure Control Valve

Claims (2)

A cylinder body, a piston slidably fitted in the cylinder body, a cap-side first pressure chamber and a rod-side second pressure chamber defined by the piston in the cylinder body, and a piston fixed to the piston. A hydraulic cylinder having an output rod penetrating the second pressure chamber and connected to the operated device;
A speed / position detector that is provided on the output rod of the hydraulic cylinder and detects the moving speed or the position of the output rod every moment ;
A first supply / discharge circuit connected to the first pressure chamber;
A second supply / exhaust circuit connected to the second pressure chamber;
A hydraulic source with a hydraulic pump connected to the oil tank;
The oil tank and the hydraulic pump of the hydraulic source are connected to the upstream side, and the first circuit in the unit connected to the first supply / discharge circuit and the second circuit in the unit connected to the second supply / discharge circuit are downstream. A directional control valve connected to
A flow rate / flow rate detector that is provided in one of the first circuit in the unit or the second circuit in the unit and detects the flow rate or flow rate of the circuit;
A hydraulic unit comprising a pressure-compensated flow rate control valve that is provided on the other side and controls the flow rate in the supply and discharge direction of the circuit; and
A monitoring device for identifying leakage and a leakage circuit based on the output of the flow velocity / flow rate detector and the output fluctuation pattern of the speed / position detector;
A leak detection device for a hydraulic cylinder circuit, comprising: A cylinder body, a piston slidably fitted in the cylinder body, a cap-side first pressure chamber and a rod-side second pressure chamber defined by the piston in the cylinder body, and a piston fixed to the piston. And an output rod that penetrates the second pressure chamber and is connected to the actuated device, and causes the load of the actuated device to act on the first pressure chamber or the second pressure chamber via the output rod. A cylinder,
A speed / position detector for detecting the moving speed or the momentary position of the output rod;
A first supply / discharge circuit connected to the first pressure chamber;
A second supply / exhaust circuit connected to the second pressure chamber;
A hydraulic source with a hydraulic pump connected to the oil tank;
The oil tank and the hydraulic pump of the hydraulic source are connected to the upstream side, and the first circuit in the unit connected to the first supply / discharge circuit and the second circuit in the unit connected to the second supply / discharge circuit are downstream. A directional control valve connected to
A pilot check valve that is provided on the downstream side of the direction switching valve and opens and closes the first circuit in the unit and the second circuit in the unit corresponding to the operating position of the direction switching valve;
A flow rate / flow rate detector that is provided downstream of the pilot check valve in one of the first circuit in the unit or the second circuit in the unit and detects the flow rate or flow rate of the circuit;
A hydraulic unit comprising a pressure-compensated flow rate control valve that is provided on the other side and controls the flow rate of the circuit; and
A monitoring device that identifies a leak and a leak location based on the output of the flow velocity / flow rate detector and the output fluctuation pattern of the speed / position detector;
A leak detection device for a hydraulic cylinder circuit, comprising:

Images