JP2019199897A - Fluid leakage detection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently detect fluid leakage in a fluid pressure cylinder. A fluid leakage detection system (100) is provided with a hydraulic cylinder (1), a measuring unit (10) for detecting leakage of hydraulic oil through an annular gap (8) between a piston rod (3) and a cylinder head (5), and a measuring unit (10). And a controller 80 for acquiring the measurement result of the measurement unit 10, the measurement unit 10 measures the pressure and the temperature according to a predetermined operation condition, and transmits the measurement result to the controller 80. And a determination unit 84 that determines whether or not the operating condition is changed by the condition setting unit 83 according to the measurement result of the measurement unit 10. [Selection diagram] Figure 1

Description

  The present invention relates to a fluid leak detection system.

  Patent Document 1 discloses a pressure detector that detects the pressure of the working fluid as a fluid detector that detects the state of the working fluid supplied to the fluid pressure device. Such a pressure detector has a detection part which contacts working fluid, and an output part which outputs the value detected by the detection part to the outside.

JP 2006-28744 A

  In order to detect fluid leakage through the seal member on the outer periphery of the piston rod in the fluid pressure cylinder, it is conceivable to detect the leaked fluid using a fluid detector as disclosed in Patent Document 1. In this case, for example, the fluid leakage can be detected early and reliably as the detection interval by the detector is shorter. On the other hand, if the detection interval is short, unnecessary data such as data in a state where the fluid pressure cylinder is not operated may be collected.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a fluid leak detection system capable of efficiently detecting a fluid leak in a fluid pressure cylinder.

  The present invention is a fluid leakage detection system for detecting leakage of a working fluid in a fluid pressure cylinder, and is provided in the fluid pressure cylinder, and the state quantity of the working fluid leaking through a gap between a piston rod and a cylinder head is determined. A measurement unit for measuring, and a controller for obtaining a measurement result of the measurement unit. The measurement unit has a measurement unit that measures and outputs a state quantity of the working fluid in the detection space under a predetermined operating condition, and performs measurement. The unit is configured to be able to measure at least one of the pressure and temperature of the detection space, and the controller determines a leakage determination unit that determines leakage of the working fluid based on a state quantity measured by the measurement unit, and an operation condition of the measurement unit. A condition setting unit to be set, and a determination unit that determines whether or not to change the operating condition according to at least one of pressure and temperature measured by the measurement unit. The features.

  In this invention, the operating condition of the measurement unit is changed according to at least one of the pressure and temperature measured by the measurement unit of the measurement unit. As a result, for example, the operating condition is set to an operating condition with a relatively low operating frequency at normal times, and when an indication of fluid leakage is detected from the measurement result, the operating condition is changed to increase the operating frequency to Detection accuracy can be increased. As described above, according to the present invention, the measurement unit can be operated under optimum operating conditions in each case where high detection accuracy is required and in cases where high detection accuracy is not required.

  According to the present invention, the measurement unit is configured to be able to measure pressure, and the determination unit compares pressure data obtained before and after the time series obtained from the measurement result of the measurement unit to determine a change in operating condition. Features.

  In the present invention, the measurement unit measures the pressure for each measurement cycle having a predetermined time length and is repeated at a predetermined time interval, and the determination unit is pressure data that moves back and forth in time series within the same measurement cycle. To determine whether the operating condition is changed.

  In the present invention, the measurement unit measures pressure for each measurement cycle having a predetermined time length and repeated at a predetermined time interval, and the determination unit includes pressure data in the current measurement cycle input to the controller, It is characterized by comparing the pressure data in the measurement cycle before the previous time and determining the change of the operating condition.

  The present invention is characterized in that the determination unit determines that the operating condition is to be changed if the difference between the pressure data preceding and following in time series is equal to or greater than a predetermined difference threshold value.

  In these present inventions, the occurrence of oil leakage can be detected by comparing the pressure data that are mixed in time series.

  The present invention includes, as a measurement unit, a first measurement unit and a second measurement unit that are respectively provided in a pair of fluid pressure cylinders that drive the same drive target, and the determination unit includes a measurement result of the first measurement unit, The measurement result of the second measurement unit is compared.

  In the present invention, by comparing the pressure data of a pair of fluid pressure cylinders that drive the same drive object, it is possible to detect the sign of the occurrence of accidental oil leakage occurring in one of the fluid pressure cylinders. it can.

  The present invention is characterized in that when the operating condition is determined to be changed by the determining section, the operating conditions of the measuring section in each of the first measuring unit and the second measuring unit are changed to the same conditions.

  In the present invention, the operating conditions of the measuring units in each of the first measuring unit and the second measuring unit are changed under the same conditions so that the fluid pressure cylinder can be kept in the same operating state even after the operating conditions are changed. The measurement results of each other can be compared. Thereby, it becomes easy to compare the measurement results of the first measurement unit and the second measurement unit.

  The present invention is characterized in that the determination unit calculates an operation time of the fluid pressure cylinder and determines a change in the operation condition based on the operation time.

  The present invention is characterized in that the measurement unit is configured to be able to measure a temperature, and the determination unit calculates an operation time based on a measurement time when the measurement unit detects a temperature equal to or higher than a predetermined temperature threshold.

  These inventions can detect signs of oil leakage based on the life of the rod seal.

  In the present invention, the controller includes an information acquisition unit that acquires operation information of the fluid pressure cylinder or the fluid pressure driven machine including the fluid pressure cylinder, and the determination unit operates based on the operation information acquired by the information acquisition unit. Time is calculated.

  In the present invention, the fluid pressure drive machine is a construction machine, and the determination unit acquires an on / off signal of an ignition switch for starting the construction machine as operation information, and the accumulated time in which the ignition switch is turned on Based on the above, the operation time is calculated.

  In these present inventions, in addition to the measurement result of the measurement unit, an indication of oil leakage based on the life of the rod seal can be detected based on the operation information of the fluid pressure cylinder or the fluid pressure drive machine.

  In the present invention, the measurement unit measures at least one of pressure and temperature at a predetermined sampling period for each measurement cycle having a predetermined time length and repeated every predetermined time interval, and has a predetermined data capacity. When at least one of pressure and temperature is measured by the transmission capacity, the measurement result is output to the controller, and the condition setting unit operates as the operating condition, the time length of the measurement cycle, the time interval at which the measurement cycle is repeated, the sampling period, and It is characterized by changing at least one of the transmission capacities.

  In the present invention, the measurement unit has a battery as a power source, and the condition setting unit determines a mode of changing the operating condition based on the remaining battery level of the battery.

  In the present invention, it is possible to achieve both improvement in detection accuracy of fluid leakage and suppression of reduction in battery life.

  According to the present invention, the detection of fluid leakage by the fluid leakage detection system is made efficient.

It is a mimetic diagram showing the composition of the fluid leak detection system concerning the embodiment of the present invention. 1 is a partial cross-sectional view of a hydraulic cylinder according to an embodiment of the present invention. It is an expanded sectional view of the hydraulic cylinder which concerns on embodiment of this invention. It is a block diagram which shows the measurement unit of the fluid leak detection system which concerns on embodiment of this invention. It is a block diagram which shows the control unit of the fluid leak detection system which concerns on embodiment of this invention. It is a schematic graph for demonstrating the action | operation of the fluid leak detection system which concerns on embodiment of this invention, A vertical axis | shaft shows the data capacity accumulate | stored in a data storage part, and a horizontal axis shows time. It is a block diagram which shows the modification of the control unit of the fluid leak detection system which concerns on embodiment of this invention.

  Hereinafter, a fluid leak detection system 100 according to an embodiment of the present invention will be described with reference to the drawings.

  First, an overall configuration of a fluid pressure system 101 including a fluid leak detection system 100 will be described with reference to FIG.

  The fluid pressure system 101 is used for a construction machine as a fluid pressure drive machine, particularly a hydraulic excavator. The fluid pressure system 101 controls the flow of working fluid supplied to and discharged from a plurality of fluid pressure cylinders to drive the fluid pressure cylinders.

  As shown in FIG. 1, the fluid pressure system 101 includes a hydraulic cylinder 1 as a fluid pressure cylinder that drives a drive target (not shown) such as a boom, an arm, and a bucket, and hydraulic oil supplied to and discharged from the hydraulic cylinder 1 ( Fluid leakage detection that detects oil leakage through a fluid pressure control device 102 that controls the operation of the hydraulic cylinder 1 by controlling the working fluid) and a rod seal 11 (see FIG. 3) as a seal member provided in the hydraulic cylinder 1 System 100.

  In the present embodiment, the fluid pressure system 101 includes a pair of hydraulic cylinders 1 that drive the same drive target. In the fluid pressure system 101, a pair of hydraulic cylinders 1 operate in synchronization with each other, thereby driving one drive target. Hereinafter, each of the pair of hydraulic cylinders 1 is also referred to as “hydraulic cylinder 1a” and “hydraulic cylinder 1b”.

  As shown in FIG. 2, the hydraulic cylinder 1 includes a cylindrical cylinder tube 2, a piston rod 3 inserted into the cylinder tube 2, and a piston 4 provided at the base end of the piston rod 3. The piston 4 is slidably provided along the inner peripheral surface of the cylinder tube 2. The inside of the cylinder tube 2 is partitioned by a piston 4 into a rod side chamber (fluid pressure chamber) 2a and an anti-rod side chamber 2b.

  The tip of the piston rod 3 extends from the open end of the cylinder tube 2. When hydraulic oil is selectively guided from a hydraulic source (not shown) to the rod side chamber 2a or the anti-rod side chamber 2b, the piston rod 3 moves relative to the cylinder tube 2. Thereby, the hydraulic cylinder 1 is expanded and contracted.

  A cylinder head 5 through which the piston rod 3 is inserted is provided at the open end of the cylinder tube 2. The cylinder head 5 is fastened to the open end of the cylinder tube 2 using a plurality of bolts 6.

  Since the fluid pressure control device 102 can adopt a known configuration, detailed illustration and description thereof are omitted. The fluid pressure control device 102 controls the flow of hydraulic oil guided from the hydraulic pump (hydraulic source) to each hydraulic cylinder 1 to operate each hydraulic cylinder 1.

  Next, the fluid leak detection system 100 will be specifically described.

  In the fluid leak detection system 100, hydraulic oil leaks from the rod side chamber 2a between the outer peripheral surface of the piston rod 3 and the inner peripheral surface of the cylinder head 5 in each of the pair of hydraulic cylinders 1 that drive the same drive target. Detect the occurrence of oil leakage (fluid leakage).

  As shown in FIGS. 1 and 3, the fluid leak detection system 100 includes an annular gap (hereinafter referred to as “annular gap 8”) provided between the outer peripheral surface of the piston rod 3 and the inner peripheral surface of the cylinder head 5. And a control unit 70 for determining the occurrence of oil leakage in the hydraulic cylinder 1 based on the measurement result of the measurement unit 10.

  As shown in FIG. 1, the measurement unit 10 is provided in each of a pair of hydraulic cylinders 1. Hereinafter, as necessary, the measurement unit 10 provided in one hydraulic cylinder 1a is also referred to as “first measurement unit 10a”, and the measurement unit 10 provided in the other hydraulic cylinder 1b is also referred to as “second measurement unit 10b”.

  As shown in FIG. 3, the measurement unit 10 includes a rod seal 11 that is provided in the cylinder head 5 and seals an annular gap 8 between the outer peripheral surface of the piston rod 3 and the inner peripheral surface of the cylinder head 5, and a rod side chamber. 2a, a detection space 20 through which hydraulic oil leaking beyond the rod seal 11 is guided; a detection seal 12 provided in the cylinder head 5 to seal the annular gap 8; and the detection space 20 together with the rod seal 11; The communication passage 21 communicating with the space 20, the relief valve 30 that opens when the pressure of the communication passage 21 reaches the relief pressure and releases the pressure of the communication passage 21, and leaked into the detection space 20 beyond the rod seal 11. The measuring part 50 which measures the state quantity of hydraulic fluid, and the housing 40 which accommodates the relief valve 30 and the measuring part 50 are provided.

  On the inner periphery of the cylinder head 5, a rod seal 11, a bush 13, a detection seal 12, and a dust seal 14 are interposed in this order from the base end side (right side in FIG. 3) to the distal end side (left side in FIG. 3). Is done. The rod seal 11, the bush 13, the detection seal 12, and the dust seal 14 are accommodated in annular grooves 5a, 5b, 5c, and 5d formed on the inner periphery of the cylinder head 5, respectively.

  When the bush 13 is in sliding contact with the outer peripheral surface of the piston rod 3, the piston rod 3 is supported so as to move in the axial direction of the cylinder tube 2.

  The rod seal 11 is compressed between the outer periphery of the piston rod 3 and the annular groove 5 a on the inner periphery of the cylinder head 5, thereby sealing the annular gap 8. The rod seal 11 faces the rod side chamber 2a (see FIG. 2), and the rod seal 11 prevents the hydraulic oil in the rod side chamber 2a from leaking to the outside. The rod seal 11 is a so-called U-packing.

  The dust seal 14 is provided on the cylinder head 5 so as to face the outside of the cylinder tube 2 and seals the annular gap 8. The dust seal 14 sweeps out dust adhering to the outer peripheral surface of the piston rod 3 and prevents the dust from entering the cylinder tube 2 from the outside.

  Like the rod seal 11, the detection seal 12 is compressed between the outer periphery of the piston rod 3 and the annular groove 5 c on the inner periphery of the cylinder head 5, thereby sealing the annular gap 8. The detection seal 12 is provided between the rod seal 11 and the dust seal 14 and defines the detection space 20 together with the rod seal 11. That is, the detection space 20 is a space defined by the piston rod 3, the cylinder head 5, the rod seal 11, and the detection seal 12 (in this embodiment, in addition to the bush 13). Like the rod seal 11, the detection seal 12 is a U-packing.

  The communication path 21 is formed across the cylinder head 5 and the housing 40 so as to communicate with the detection space 20. The communication path 21 includes a first communication path 22 formed in the cylinder head 5 and opening to the detection space 20, and a second communication path 23 formed in the housing 40 and communicating with the first communication path 22. The hydraulic oil in the rod side chamber 2 a leaking from the rod seal 11 is guided to the communication path 21 through the annular gap 8 and the detection space 20.

  The relief valve 30 opens when the pressure of the hydraulic oil in the second communication passage 23 reaches a predetermined pressure (relief pressure), and discharges the hydraulic oil in the detection space 20 to the outside through the second communication passage 23. Thereby, the pressure in the detection space 20 is limited to the relief pressure by the relief valve 30. Since the structure of the relief valve 30 can adopt a known configuration, detailed illustration and description are omitted.

  The housing 40 is fixed to the end of the cylinder head 5 by press fitting. The housing 40 is further formed with a sensor accommodation hole 41 for accommodating the measurement unit 50 and a valve accommodation hole 42 for accommodating the relief valve 30. The sensor accommodation hole 41 and the valve accommodation hole 42 communicate with the second communication path 23, respectively, and the valve accommodation hole 42 communicates with the second communication path 23 on the first communication path 22 side (upstream side) with respect to the sensor accommodation hole 41. doing.

  The measuring unit 50 performs the measurement of the pressure as the state quantity of the hydraulic oil and the output of the measurement result to the control unit 70 under predetermined operating conditions. In other words, the measuring unit 50 performs pressure measurement and measurement result output at a predetermined operating frequency based on predetermined operating conditions. The operation frequency includes a measurement frequency at which the measurement unit 50 measures the pressure and temperature, and a transmission frequency at which the measurement result is transmitted from the measurement unit 50 to the control unit 70. Moreover, the measurement part 50 is comprised so that the temperature in the detection space 20 can also be measured.

  As shown in FIG. 4, the measuring unit 50 outputs a command signal to the sensor unit 51, which is a pressure temperature sensor capable of measuring both pressure and temperature, and acquires a measurement result of the sensor unit 51. A sensor controller 60; a first communication unit 52 that transmits and receives signals to and from the control unit 70 by wireless communication; a sensor unit 51, a sensor controller 60, and a battery 54 that is a power source (power source) for the first communication unit 52; Have

  The measurement unit 50 is configured by incorporating a sensor unit 51, a sensor controller 60, and a battery 54 in the same casing, and is arranged in a sensor receiving hole 41 formed in the housing 40 as shown in FIG. Part is housed. The measuring unit 50 is fixed to the screw hole 24 communicating with the second communication path 23 of the housing 40 by screwing.

  The sensor unit 51 measures the pressure and temperature in the detection space 20. Thereby, the pressure and temperature of the hydraulic fluid guided to the detection space 20 through the first communication path 22 and the second communication path 23 (see FIG. 3) are measured by the sensor unit 51. The operation of the sensor unit 51 will be described later in detail.

  The battery 54 is electrically connected to the sensor controller 60, the sensor unit 51, and the first communication unit 52. The sensor controller 60, the sensor unit 51, and the first communication unit 52 are each activated by power supply from the battery 54.

  The sensor controller 60 includes a microcomputer having a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and I / O interface (input / output interface). The RAM stores data in the processing of the CPU, the ROM stores a control program of the CPU in advance, and the I / O interface is used for input / output of information with the connected device. The sensor controller 60 may be composed of a plurality of microcomputers. The sensor controller 60 is programmed so that at least processing necessary for control by the sensor controller 60 described in this specification can be executed. The sensor controller 60 may be configured as a single device, or may be divided into a plurality of devices, and each control by the sensor controller 60 may be configured to be distributedly processed by the plurality of devices.

  The sensor controller 60 includes a command unit 61 that outputs a command signal to the sensor unit 51, and a data storage unit 62 that acquires and stores the measurement result of the sensor unit 51 and the remaining battery level of the battery 54.

  Based on the command signal from the command unit 61, the sensor unit 51 operates under predetermined operating conditions, and measures the pressure and temperature of the detection space 20. The measurement result of the sensor unit 51 is input to the data storage unit 62.

  The data storage unit 62 accumulates the measurement result of the sensor unit 51 and the remaining battery level of the battery 54, and outputs the accumulated data to the control unit 70 under a predetermined operating condition (transmission frequency). The transmission frequency at which data is output from the data storage unit 62 can be changed according to the command signal from the command unit 61.

  The first communication unit 52 is electrically connected to the sensor controller 60 and transmits and receives signals to and from the sensor controller 60. The first communication unit 52 is configured to be capable of wireless communication with the control unit 70.

  The control unit 70 is arrange | positioned in the cab (cabin) of a construction machine, for example. As shown in FIG. 5, the control unit 70 includes a second communication unit 71 that transmits and receives signals by wireless communication with the first communication unit 52 of the measurement unit 50, and the measurement unit 50 of the measurement unit 10 through the second communication unit 71. And a controller 80 that transmits and receives signals to and from the controller.

  The controller 80 is constituted by a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and an I / O interface (input / output interface). The RAM stores data in the processing of the CPU, the ROM stores a control program of the CPU in advance, and the I / O interface is used for input / output of information with the connected device. The controller 80 may be composed of a plurality of microcomputers. The controller 80 is programmed so that at least processing necessary for control by the controller 80 described herein can be executed. The controller 80 may be configured as a single device, or may be divided into a plurality of devices, and may be configured so that each control in the present embodiment is distributedly processed by the plurality of devices.

  The controller 80 acquires the measurement result of the measurement unit 50 and determines whether or not oil leakage has occurred in the hydraulic cylinder 1 based on the measurement result of the measurement unit 50. Further, the controller 80 changes the operating condition of the measurement unit 50 of the measurement unit 10 through the second communication unit 71.

  The controller 80 changes a storage unit 81 that stores the measurement result of the measurement unit 50, a leak determination unit 82 that determines whether oil leakage has occurred according to the measurement result of the measurement unit 50, and changes the operating conditions of the measurement unit 50 And a determination unit 84 that determines whether the condition setting unit 83 changes the operating condition of the measurement unit 50 according to the measurement result of the measurement unit 50.

  Information transmitted from the sensor controller 60 of the measurement unit 50 (the pressure and temperature of the detection space 20 and the remaining battery level of the battery 54) is stored in the storage unit 81 and also input to the determination unit 84 and the leak determination unit 82. The

  The leak determination unit 82 determines whether or not an oil leak has occurred in each of the pair of hydraulic cylinders 1 based on the pressure value as the state quantity measured by the sensor unit 51 of the first measurement unit 10a and the second measurement unit 10b. Determine. The leakage determination unit 82 determines the occurrence of oil leakage every time the measurement results of the first measurement unit 10a and the second measurement unit 10b are input.

  Based on the measurement result of the measurement unit 50 of the measurement unit 10, the determination unit 84 determines whether there is a sign that oil leakage occurs in the hydraulic cylinder 1 to which the measurement unit 10 is attached. If the determination unit 84 determines that there is an indication of oil leakage, the determination unit 84 determines to change the operating condition of the measurement unit 50. The determination result of the determination unit 84 is input to the condition setting unit 83.

  If the determination result of the determination unit 84 is to change the operating condition, the condition setting unit 83 changes the command unit 61 of the sensor controller 60 through the first and second communication units 52 and 71. A command signal including various operating conditions is transmitted. When receiving a command signal from the condition setting unit 83, the command unit 61 of the sensor controller 60 outputs a command signal to the sensor unit 51 and / or the data storage unit 62 so as to operate under a new operating condition.

  Next, the operation of the fluid leak detection system 100 will be described.

  First, the operation of the measurement unit 50 of the measurement unit 10 will be specifically described.

  The sensor unit 51 measures pressure and temperature at a predetermined sampling period for each measurement cycle having a predetermined time length and repeated at predetermined time intervals. The data storage unit 62 transmits the accumulated data (the measurement result of the sensor unit 51 and the remaining battery level of the battery 54) to the control unit 70 through the first communication unit 52 at a predetermined frequency. In the following, the time length of the measurement cycle (the time from the start to the end of the measurement cycle) is “measurement time Td”, and the time interval from the start of a certain measurement cycle to the start of the next measurement cycle is “cycle interval CT”. . The sampling period of the sensor unit 51 is “sampling period SC”, and the data capacity accumulated until the data storage unit 62 transmits (outputs) the measurement result is “transmission capacity Dc”. The operating conditions of the measurement unit 50 are the measurement time Td, the sampling cycle SC, the cycle interval CT, and the measurement results of the sensor unit 51, which are conditions under which the sensor unit 51 detects pressure and temperature. The transmission capacity Dc to be transmitted to the controller 80 is included.

  FIG. 6 is a schematic graph showing the relationship between time and the data capacity of the measurement result accumulated in the data storage unit 62. As shown in FIG. 6, the sensor unit 51 measures the pressure and temperature in the detection space 20 for each sampling period SC during the measurement time Td, and measures the pressure and temperature when the measurement time Td elapses from the start of measurement. Exit. After the measurement of pressure and temperature is completed, the sensor unit 51 enters a standby state (sleep state) in which pressure and temperature are not measured.

  The measurement result of the sensor unit 51 is accumulated in the data storage unit 62. The data storage unit 62 outputs the accumulated data to the first communication unit 52 every time the measurement result is accumulated by the transmission capacity Dc. In FIG. 6, the data capacity of the measurement results for five times corresponds to the transmission capacity Dc. The first communication unit 52 wirelessly transmits the data output from the data storage unit 62 to the second communication unit 71 of the controller 80. The transmission frequency is determined according to the transmission capacity Dc in which data is transmitted from the data storage unit 62 of the sensor controller 60 in the measurement unit 50 to the controller 80.

  As shown in FIG. 6, the data storage unit 62 erases the accumulated data every time the accumulated data is output to the first communication unit 52, but is not limited to this, and continues to accumulate data. But you can.

  Thus, the sensor unit 51 measures the pressure and temperature in the detection space 20 intermittently rather than constantly (continuously). Further, the measurement result of the sensor unit 51 is not immediately transmitted to the controller 80, but is transmitted to the controller 80 when only the transmission capacity Dc is accumulated in the data storage unit 62. That is, the measurement result of the sensor unit 51 is intermittently transmitted to the controller 80. Since the measurement by the sensor unit 51 and the transmission of the measurement result from the data storage unit 62 are performed intermittently, power consumption can be reduced. The sensor unit 51 and the data storage unit 62 can also perform continuous measurement and output of measurement results (data transmission), respectively.

  Next, determination of oil leakage by the controller 80 will be described.

  When the deterioration of the rod seal 11 of the hydraulic cylinder 1 proceeds, the oil pressure in the rod side chamber 2a is guided into the detection space 20 beyond the rod seal 11. Therefore, the pressure and temperature of the detection space 20 increase with the deterioration of the rod seal 11. In the fluid leak detection system 100, the pressure in the detection space 20 is measured by the measurement unit 50 of the measurement unit 10, and the controller 80 of the control unit 70 determines whether or not an oil leak has occurred based on the measurement result. Oil leakage in the cylinder 1 is detected. In this specification, “deterioration” of the rod seal 11 includes wear and damage. The wear is caused by a steady load such as reciprocation of the piston rod 3 and indicates deterioration due to the life. Damage refers to deterioration caused by accidental load due to an accident or the like.

  The oil leakage determination will be specifically described. In the present embodiment, the oil leakage determination is performed based on the pressure in the detection space 20. Each time the measurement result of the sensor unit 51 is transmitted from the data storage unit 62 of the sensor controller 60, the leak determination unit 82 of the controller 80 acquires the maximum pressure value as pressure data from the transmitted data group. The leak determination unit 82 compares the maximum pressure value with a predetermined determination threshold, and determines that oil leakage has occurred if the maximum pressure value is equal to or greater than the determination threshold. When it is determined by the leak determination unit 82 that an oil leak has occurred, the determination result is transmitted to a notification unit (not shown), and the operator is notified of the occurrence of the oil leak. In this way, oil leakage in the hydraulic cylinder 1 is detected. On the other hand, when the maximum pressure value is smaller than the determination threshold, the leakage determination unit 82 determines that no oil leakage has occurred.

  In the present specification, “no oil leakage has occurred” does not mean a strict meaning, but only means that no hydraulic oil leaks into the detection space 20 beyond the rod seal 11. Absent. For example, even when the hydraulic oil leaks from the rod side chamber 2a into the detection space 20, if the deterioration (wear / damage) of the rod seal 11 is acceptable, the leakage determination unit 82 It is determined that no oil leak has occurred. That is, “the oil leak has occurred” refers to a state in which the deterioration (wear / damage) of the rod seal 11 exceeds the allowable range. Therefore, the determination threshold is set according to the degree of allowable deterioration (wear / damage) of the rod seal 11.

  Moreover, the pressure data used for the determination of oil leakage is not limited to the maximum pressure value, and other data may be used. For example, the pressure data may be one measurement value included in the transmitted data group such as the minimum pressure value and the median value, or a value calculated by calculating the measurement value like an average value. Also good. That is, the pressure data includes the pressure measurement value itself measured by the sensor unit 51 and a value obtained from the measurement value.

  Next, the change of the operating condition of the measurement part 50 is demonstrated.

  The shorter the sampling period SC and cycle interval CT of the sensor unit 51 and the longer the measurement time Td, the higher the measurement frequency of the sensor unit 51. Thereby, more pressure and temperature are measured, the data capacity acquired by the sensor part 51 becomes large, and the detection accuracy of an oil leak improves. For example, in the case where the sensor unit 51 constantly measures the pressure and temperature in the detection space 20 without entering the standby state (in other words, when the measurement time Td = cycle interval CT), the oil leak occurs immediately. The occurrence of oil leakage can be detected. Further, the smaller the transmission capacity Dc, the higher the transmission frequency. Since the occurrence of oil leaks is frequently determined by increasing the transmission frequency, the accuracy of detecting oil leaks is improved. As described above, the higher the operation frequency of the measurement unit 50 (the measurement frequency of the sensor unit 51 and the transmission frequency from the data storage unit 62), the more accurately the oil leak detection system 100 detects the oil leak.

  Conversely, the longer the sampling period SC and cycle interval CT and the shorter the measurement time Td, the lower the frequency of measurement of the sensor unit 51, and the smaller the pressure and temperature data capacity measured. Further, the transmission frequency is lower as the transmission capacity Dc is larger. That is, since the number of times the measurement result is output from the sensor controller 60 is small, the number of times that the controller 80 determines the occurrence of oil leakage is small. The lower the operation frequency of the measurement unit 50, the lower the oil leakage detection accuracy, but the data processing load is reduced and the power consumption of the battery 54 can be suppressed.

  Thus, in order to improve the detection accuracy of oil leakage, it is preferable that the operation frequency of the measurement unit 50 (the measurement frequency of the sensor unit 51 and the transmission frequency from the data storage unit 62) is high. On the other hand, when the operation frequency of the measuring unit 50 is increased, unnecessary data such as data in a state where the construction machine or the hydraulic cylinder 1 is not operated may be collected. Further, when the measurement frequency and the transmission frequency are high, the power consumption of the battery 54 by the sensor unit 51, the first communication unit 52, and the sensor controller 60 also increases.

  Therefore, in the fluid leak detection system 100 according to the present embodiment, change control for changing the operating condition of the measurement unit 50 according to the situation is executed.

  In the fluid leakage detection system 100, when the risk of oil leakage is small, the measurement unit 50 is operated under conditions where the operation frequency is relatively low, thereby suppressing unnecessary data collection and power consumption. . On the other hand, when an indication of the occurrence of oil leakage appears, the measurement unit 50 is operated under conditions where the operation frequency is relatively high so that the occurrence of oil leakage can be detected early and reliably. Thus, before the oil leak occurs, the sign is detected, and the operating condition of the measuring unit 50 is changed, so that the oil leak can be detected efficiently.

  In the change control, a sign detection process that detects signs of oil leakage as a criterion for determining whether or not to change the operating conditions, and if an oil leak occurrence sign is detected, the operating frequency is increased to And a condition changing process for changing the operating condition so as to improve the leak detection accuracy.

[Sign detection processing]
The method of detecting the sign of oil leakage includes pressure sign detection for detecting a sign based on the pressure data of the sensor unit 51, and measurement of the first measurement unit 10a and the second measurement unit 10b provided in the pair of hydraulic cylinders 1. Comparison sign detection for comparing the results and time sign detection based on the operation time calculated from the temperature data of the sensor unit 51 are included. In this embodiment, the controller 80 is programmed to execute pressure sign detection, comparative sign detection, and time sign detection. The controller 80 may execute pressure sign detection, comparative sign detection, and time sign detection independently, or may execute two or more simultaneously (in parallel).

  Hereinafter, pressure sign detection will be described.

  In the pressure sign detection, pressure data moving back and forth in time series is compared to detect a sign of oil leakage in the hydraulic cylinder 1.

  As a method for comparing the pressure data before and after in time series, there are a comparison of pressure data in the same measurement cycle and a comparison of pressure data in different measurement cycles.

  Comparison of pressure data within the same measurement cycle means, for example, as shown in FIG. 6, the maximum pressure value included in the current data group G11 transmitted from the measurement unit 50 to the controller 80 and the same measurement cycle. The maximum pressure value included in the data group G12 transmitted before the data group G11 is compared. The determination unit 84 acquires the respective maximum pressure values from the data group G11 transmitted this time and the data group G12 transmitted last time. If the difference in the maximum pressure value is equal to or greater than a predetermined difference threshold, the determination unit 84 determines that the operating condition is to be changed, assuming that there is an indication of the occurrence of oil leakage. The data group to be compared is not limited to the previous data group, but may be a previous data group transmitted in the same measurement cycle (for example, data group G13 in FIG. 6).

  The comparison of pressure data in different measurement cycles is, for example, comparing pressure data in the current measurement cycle with pressure data in the previous measurement cycle. As shown in FIG. 6, if three data transmissions are performed in the measurement cycle, the maximum pressure values of the data groups G11, G12, and G13 transmitted in the current measurement cycle correspond to the previous measurement cycle. The maximum pressure values of the data groups G21, G22, and G23 transmitted in order are compared with each other. If the difference between the previous maximum pressure value and the current maximum pressure value is greater than or equal to the difference threshold value, the determination unit 84 determines that there is an indication of the occurrence of oil leakage and changes the operating condition. The measurement cycle to be compared is not limited to the previous measurement cycle. For example, the measurement cycle may be compared with the previous measurement cycle, for example, the current measurement cycle and the measurement cycle of the previous day detected at substantially the same time.

  As described above, the pressure data in the detection space 20 accompanying the deterioration of the rod seal 11, in other words, the sign of the occurrence of oil leakage can be detected by comparing the pressure data moving back and forth in time series.

  Next, comparison sign detection will be described.

  Usually, the pair of hydraulic cylinders 1a and 1b that drive the same drive object have the same operation history and usage status, and therefore the pressure and temperature of the detection space 20 in both of them are independent of the deterioration of the rod seal 11. It ’s hard to make a big difference. However, for example, when an accidental impact is applied only to the rod seal 11 of one hydraulic cylinder 1a, one of the rod seals 11 may be relatively greatly deteriorated. In such a case, oil leakage occurs from one of the deteriorated rod seals 11, and an increase in pressure or temperature occurs only in one hydraulic cylinder 1a.

  Therefore, in the comparative sign detection, by comparing the measurement results of the first measurement unit 10a and the second measurement unit 10b respectively provided in the pair of hydraulic cylinders 1a and 1b, an indication of oil leakage in the pair of hydraulic cylinders 1a and 1b is obtained. To detect.

  In a state where no oil leakage has occurred, the first measurement unit 10a and the second measurement unit 10b operate in synchronization with each other under the same operating conditions. That is, the sensor units 51 of the first measurement unit 10a and the second measurement unit 10b measure pressure and temperature at the same timing and by the same measurement cycle. The measurement results of the first measurement unit 10a and the second measurement unit 10b are transmitted from the respective sensor controllers 60 to the controller 80 at the same timing.

  The determination unit 84 of the controller 80 acquires pressure data or temperature data from the measurement results of the first measurement unit 10a and the second measurement unit 10b transmitted at the same timing. Note that the temperature data is not limited to the actually measured temperature value, as with the pressure data, but is the maximum or minimum value of the temperature measurement value within a predetermined time range, and further, for example, the temperature measurement value such as an average value. The value obtained by calculating is also included. In this embodiment, the determination part 84 acquires the maximum pressure value in each data group transmitted from the 1st measurement unit 10a and the 2nd measurement unit 10b at the same timing as pressure data, and compares both. If the difference between the maximum pressure values is equal to or greater than a predetermined comparison threshold, the determination unit 84 determines that there is an indication of oil leakage and determines that the operating condition is to be changed.

  In this way, by comparing the measurement results of the first measurement unit 10a and the second measurement unit 10b provided in the pair of hydraulic cylinders 1a and 1b, one of the hydraulic cylinders 1 associated with the accidental deterioration of the rod seal 11 is compared. An increase in pressure or temperature in the detection space 20, that is, a sign of occurrence of oil leakage is detected.

  Next, time sign detection will be described.

  Since the rod seal 11 is in sliding contact with the piston rod 3 of the hydraulic cylinder 1, wear (deterioration) occurs as the piston rod 3 slides. Therefore, when the time (period) in which the hydraulic cylinder 1 is used becomes long, oil leakage due to wear of the rod seal 11 is likely to occur.

  Therefore, in the time sign detection, the time (operation time) when the hydraulic cylinder 1 is used is calculated from the temperature data detected by the sensor unit 51, and the sign of oil leakage is detected.

  The determination unit 84 calculates the operating time of the hydraulic cylinder 1 from the reference time (for example, when the measurement unit 10 is attached) to the determination time when the data of the measurement unit 50 is transmitted to determine the sign of oil leakage. Calculate from The determination unit 84 considers that the hydraulic cylinder 1 is operating in a state where the temperature equal to or higher than the predetermined temperature threshold is measured, and measures the time during which the temperature equal to or higher than the temperature threshold is measured between the reference time and the determination time (sampling). Count). More specifically, when data is transmitted from the measurement unit 50, the determination unit 84 measures a temperature equal to or higher than the temperature threshold value from past temperature data stored in the storage unit 81 including the data transmitted this time. The accumulated time (sampling number) is calculated, and the accumulated time (accumulated number) is set as the operating time of the hydraulic cylinder 1. If the operating time is equal to or greater than the time threshold, the determining unit 84 determines that there is a sign of oil leakage and determines that the operating condition of the measuring unit 50 is to be changed.

  The temperature threshold is set to an appropriate value such that the hydraulic cylinder 1 is not determined to be operating due to the influence of a change in the outside air temperature, a temperature change at the start of the fluid pressure control device 102 (during idling), or the like.

  The time threshold value is appropriately set so that an indication of oil leakage can be detected according to the driving target driven by the hydraulic cylinder 1 and the situation in which the hydraulic cylinder 1 is used.

  Thus, by calculating the operating time of the hydraulic cylinder 1, a sign of the occurrence of oil leakage accompanying the life (deterioration with time) of the rod seal 11 is detected.

[Condition change processing]
Next, the change of the operating condition of the measurement unit 50 by the condition setting unit 83 will be described.

  When the determination unit 84 detects that an oil leakage sign is detected and changes the operating condition of the measurement unit 50 by pressure sign detection, comparative sign detection, and time sign detection, the determination result is input to the condition setting unit 83. Based on the determination result of the determination unit 84, the condition setting unit 83 determines how to change the operation condition such as how much the operation condition is to be changed. The condition setting unit 83 outputs a command signal for changing the operating condition to the command unit 61 of the sensor controller 60 based on the determined change mode.

  When the sign of the oil leak is detected by the determination unit 84, the condition setting unit 83 measures so that the detection accuracy of the oil leak by the fluid leak detection system 100 is improved, specifically, the operation frequency is increased. The operating condition of the unit 50 is changed. The condition setting unit 83 outputs a command signal for executing at least one of the sampling cycle SC, the cycle interval CT, the measurement time Td, and the transmission capacity Dc as a mode of changing the operation condition. To do.

  The mode of change such as how much operating condition is changed is determined based on the specification status of the hydraulic cylinder 1, the detection method for detecting signs, the remaining battery level of the battery 54 of the measuring unit 50, and the like. The more the operating condition is such that the detection accuracy is relatively high, the more data is measured by the measurement unit 50 and the transmission frequency transmitted from the measurement unit 50 to the controller 80 increases. Therefore, the power consumption in the measurement unit 50 is increased accordingly, and the life of the battery 54 is shortened. For this reason, by determining the mode of change of the operating condition based on the remaining battery level of the battery 54, it is possible to achieve both improvement in detection accuracy of oil leakage and suppression of reduction in the life of the battery 54, and detection of oil leakage. The efficiency can be further improved.

  When the command signal for changing the operating condition is input from the condition setting unit 83 of the controller 80, the command unit 61 of the sensor controller 60 receives the sensor unit 51 and / or the data storage unit 62 according to the mode of change of the operating condition. A command signal is output to. Thereby, the measurement part 50 (the sensor part 51, the data storage part 62) operate | moves by new operation conditions.

  As described above, in the fluid leak detection system 100, when the risk of oil leakage is low, the measurement unit 50 is operated under an operation condition with a relatively low operation frequency, and an oil leak sign is detected. The detection conditions can be improved by changing the operating conditions so that the operating frequency is increased. That is, in the fluid leak detection system 100, the measurement unit 50 is operated under optimum operating conditions in each of a case where high detection accuracy is required and a case where high detection accuracy is not required.

  Further, the measurement result of the measurement unit 50 may include a large value suddenly generated due to noise or the like. Due to such a suddenly large value, there is a possibility of erroneous detection in which the determination unit 84 determines that there is a sign of oil leakage even though there is no sign of oil leakage.

  Therefore, the determination unit 84 continues to detect signs even after the operating condition is changed by the condition setting unit 83. After the operating condition is changed, for example, when a state in which no sign of oil leakage is detected is continued for a predetermined time, the determination unit 84 determines that there is no sign of oil leakage. When the determination unit 84 determines that there is no sign of oil leakage, the condition setting unit 83 outputs a command signal for changing the operation condition of the measurement unit 50 to return to the original operation condition to the sensor controller 60. . Thereby, even if there is an erroneous detection of an oil leak sign, it is possible to suppress the collection of unnecessary data, and the oil leak detection efficiency by the fluid leak detection system 100 can be improved.

  In the condition change process, when an oil leak sign is detected by comparative sign detection, the operating conditions of both the first measurement unit 10a and the second measurement unit 10b may be changed, or only one of them may be changed. The operating condition may be changed.

  For example, if the cycle interval CT of the sensor unit 51 of the first measurement unit 10a and the cycle interval CT of the sensor unit 51 of the second measurement unit 10b are different, the operation at the same time (in other words, the operation of the pair of hydraulic cylinders 1 is the same) ) Cannot be compared. Therefore, when detecting the sign of oil leakage by detecting the comparative sign, it is desirable to change the operating conditions of both the first measurement unit 10a and the second measurement unit 10b in the same manner. According to this, since the operation conditions of the first measurement unit 10a and the second measurement unit 10b are maintained the same, the measurement results at the same time can be compared with each other. Therefore, the detection accuracy of the sign of oil leakage can be improved in the comparative sign detection that is continued in order to suppress erroneous detection even after the operating condition is changed.

  Further, for example, when an oil leak sign is detected by the comparative sign detection, the sign detection method may be switched from the comparative sign detection to the pressure sign detection or the time sign detection. In this case, even if only one of the first measurement unit 10a and the second measurement unit 10b in which the sign of oil leakage is detected is changed, the detection accuracy does not decrease.

  Next, a modification of this embodiment will be described.

  In the above embodiment, as a method for acquiring the operating time of the hydraulic cylinder 1, the operating time of the hydraulic cylinder 1 is calculated from the temperature data measured by the sensor unit 51. On the other hand, as shown in FIG. 7, the controller 80 may further include an information acquisition unit 85 that acquires the operation information of the construction machine, and may acquire the operation time from the operation information of the construction machine and the hydraulic cylinder 1.

  The information acquisition unit 85 acquires operation information relating to the traveling of the construction machine and the operation state of the hydraulic cylinder 1 from an ECU or the like that controls the operation of the construction machine. The operation information includes, for example, an on / off signal of an ignition switch, an operation signal generated when an operator operates an operation lever of the construction machine, a pilot signal of a control valve that controls the operation of the hydraulic cylinder 1 and the like.

  Explaining the case where the operation information is an on / off signal of the ignition switch, the information acquisition unit 85 accumulates the time during which the ignition switch is in the ON state from the reference time to the determination time. The information acquisition unit 85 calculates this accumulated time as the operating time of the hydraulic cylinder 1. Then, the determination unit 84 determines that there is a sign of oil leakage if the operating time is equal to or greater than the time threshold, as in the time sign detection. Even in this modified example, the same effect as the time sign detection is achieved. In addition, it is desirable to perform this modification in combination with pressure sign detection and / or comparative sign detection. According to this, since the sign of the oil leak is detected by two parameters having different properties of the measurement result of the sensor unit 51 and the operation information of the construction machine and the hydraulic cylinder 1, the sign detection accuracy can be improved. .

  In the above embodiment, when an indication of oil leakage is detected in the hydraulic cylinder 1, the operating condition of the measuring unit 50 provided in the hydraulic cylinder 1 is changed. On the other hand, when a sign of oil leakage is detected in a certain hydraulic cylinder 1 among the plurality of hydraulic cylinders 1 provided in the fluid pressure system 101, the operating condition of the measuring unit 50 provided in another hydraulic cylinder 1 is changed. May be.

  Moreover, in the said embodiment, the sensor part 51 measures a pressure as a state quantity used for the detection of the leakage of hydraulic fluid. The leak determination unit 82 of the controller 80 determines hydraulic oil leakage based on the pressure measured by the sensor unit 51. On the other hand, the sensor unit 51 may measure a state quantity other than the pressure, and the leakage determination unit 82 may determine hydraulic oil leakage based on the state quantity measured by the sensor unit 51. For example, the sensor unit 51 may measure the dielectric constant of the hydraulic oil guided to the detection space 20 as a state quantity, and the leakage determination unit 82 may determine the hydraulic oil leakage based on the dielectric constant.

  Moreover, in the said embodiment, the measurement part 50 is comprised so that the pressure and temperature of the detection space 20 can be measured by the sensor part 51 which is a pressure temperature sensor which can measure both a pressure and temperature. The oil leakage is determined by the pressure measured by the measurement unit 50, and the sign of the oil leakage is detected by at least one of the pressure and temperature measured by the measurement unit 50. On the other hand, the measurement unit 50 has an arbitrary configuration as long as it can measure the state quantity for detecting the oil leak and either the pressure or the temperature for detecting the sign of the oil leak. be able to. Note that “the measurement unit 50 measures the state quantity and either pressure or temperature” means that a parameter capable of determining oil leakage and detecting signs of oil leakage is measured. This means that it is not essential for the measurement unit 50 to measure two different parameters. For example, when pressure is used for detection of oil leakage and pressure is also used for detection of signs of oil leakage, the measurement unit 50 (sensor unit 51) may be any device that detects at least pressure. That is, the pressure may be commonly used for detecting oil leaks and detecting signs of oil leaks. Furthermore, the state quantity for detecting oil leak and the parameter for sign of oil leak do not mean different from each other, and may be the same parameter (for example, pressure). On the other hand, when the temperature is used to detect the sign of oil leakage, the measurement unit 50, in addition to the temperature, the state quantity for detecting the oil leakage (pressure, dielectric constant described in the above modification, etc.) Configured to measure.

  According to the above embodiment, there exist the effects shown below.

  In the fluid leak detection system 100, the operating condition of the measurement unit 50 is changed according to the measurement result of the sensor unit 51 of the measurement unit 50. As a result, when the risk of oil leakage is low, the operating condition is set to a relatively low operating frequency, and when an indication of oil leakage is detected from the measurement result, the operating condition is set to increase the operating frequency. By changing, the detection accuracy by the fluid leak detection system 100 can be increased. As described above, in the fluid leak detection system 100, the measurement unit 50 can be operated under optimum operating conditions, respectively, when high detection accuracy is required and when it is not required. Therefore, the detection of the oil leak by the fluid leak detection system 100 is made efficient.

  Moreover, in the fluid leak detection system 100, the aspect which changes the operating condition of the measurement part 50 based on the battery remaining charge of the battery 54 of the measurement part 50 is determined. Thereby, the improvement of the oil leak detection accuracy and the suppression of the decrease in the life of the battery 54 can be achieved at the same time, and the oil leak detection by the fluid leak detection system 100 can be made more efficient.

  Further, in the fluid leak detection system 100, even after the operating condition of the measurement unit 50 is changed, the controller 80 continues to detect signs of oil leak. After the operating condition is changed, when no sign of oil leakage is detected, the operating condition is returned to the state before the change. As described above, the fluid leak detection system 100 detects the sign of oil leak even after the change of the operating condition, and controls to return the operating condition to the original when the sign of oil leak is a false detection. Thereby, even if there is an erroneous detection of an oil leak sign, it is possible to suppress the collection of unnecessary data, and the oil leak detection efficiency by the fluid leak detection system 100 can be improved.

  Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

  In a hydraulic cylinder 1 having a piston rod 3 extending from the cylinder tube 2 and a cylinder head 5 through which the piston rod 3 is inserted and provided in the cylinder tube 2, an annular gap 8 between the piston rod 3 and the cylinder head 5 is passed through. A fluid leakage detection system 100 for detecting the leakage of the hydraulic fluid is a measurement unit 10 that is provided in the hydraulic cylinder 1 and measures the state quantity of the hydraulic fluid that leaks through the annular gap 8 between the piston rod 3 and the cylinder head 5. And a controller 80 that acquires the measurement result of the measurement unit 10, and the measurement unit 10 is provided in the cylinder head 5 and seals the annular gap 8 between the piston rod 3 and the cylinder head 5. A detection space 20 into which hydraulic oil leaking from the rod seal 11 is guided, and a detection space 2 A measuring unit 50 that measures and outputs at least one of pressure and temperature under a predetermined operating condition as a state quantity of the hydraulic oil, and the measuring unit 50 measures at least one of the pressure and temperature in the detection space 20. The controller 80 is configured to be capable of measurement, and includes a leak determination unit 82 that determines leakage of hydraulic oil based on the pressure measured by the measurement unit 50, a condition setting unit 83 that changes the operating condition of the measurement unit 50, and a measurement unit And a determination unit 84 that determines whether or not to change the operating condition according to the measurement result of 50.

  In this configuration, the operating condition of the measurement unit 50 is changed according to the pressure measured by the measurement unit 50 of the measurement unit 10. As a result, for example, the operating condition is set to a relatively low operating condition at normal times, and when a sign of oil leakage is detected from the measurement result, the operating condition is changed so that the operating frequency is increased, and the fluid leakage The detection accuracy of the oil leakage by the detection system 100 can be increased. As described above, in the fluid leak detection system 100, the measurement unit 10 can be operated under optimum operating conditions, respectively, when high detection accuracy is required and when it is not required. Therefore, the detection of the oil leak by the fluid leak detection system 100 is made efficient.

  Further, in the fluid leak detection system 100, the measurement unit 50 is configured to be able to measure pressure, and the determination unit 84 compares the pressure data obtained from the measurement results of the measurement unit 50 in time series and operates. Judge the change of conditions.

  Further, in the fluid leak detection system 100, the measurement unit 50 measures the pressure for each measurement cycle having a predetermined time length and repeated at predetermined time intervals, and the determination unit 84 performs the measurement within the same measurement cycle. A change in operating conditions is determined by comparing the pressure data before and after the series.

  In the fluid leak detection system 100, the measurement unit 50 measures the pressure for each measurement cycle having a predetermined time length and repeated at a predetermined time interval, and the determination unit 84 inputs the current time input to the controller 80. The pressure data in the measurement cycle is compared with the pressure data in the previous measurement cycle, and a change in the operating condition is determined.

  Further, in the fluid leak detection system 100, the determination unit 84 determines that the operating condition is to be changed if the difference between the time-series pressure data is greater than or equal to a predetermined difference threshold value.

  In these configurations, it is possible to detect the sign of the occurrence of oil leakage by comparing the pressure data moving back and forth in time series.

  The fluid leakage detection system 100 includes a first measurement unit 10a and a second measurement unit 10b provided as a measurement unit 10 in a pair of hydraulic cylinders 1 that drive the same drive target, respectively. The measurement result of the first measurement unit 10a is compared with the measurement result of the second measurement unit 10b.

  In this configuration, by comparing the pressure data of the pair of hydraulic cylinders 1 that drive the same drive target, it is possible to detect the sign of the occurrence of accidental oil leakage occurring in one of the hydraulic cylinders 1. .

  Further, in the fluid leak detection system 100, when the determination unit 84 determines that the operation condition is changed, the operation conditions of the first measurement unit 10a and the second measurement unit 10b are changed to the same conditions.

  In this configuration, the respective operating conditions of the first measuring unit 10a and the second measuring unit 10b are changed to the same conditions, so that even after the operating conditions are changed, the mutual measurement is performed in the operating state of the same hydraulic cylinder 1. The results can be compared. Thereby, the comparison of the measurement result of the 1st measurement unit 10a and the 2nd measurement unit 10b becomes easy.

  Moreover, in the fluid leak detection system 100, the determination part 84 calculates the operating time of the hydraulic cylinder 1, and determines the change of an operating condition based on the operating time.

  Further, in the fluid leak detection system 100, the measurement unit 10 is configured to be able to measure the temperature, and the determination unit 84 calculates the operation time based on the measurement time Td when the measurement unit 10 measures a temperature equal to or higher than a predetermined temperature threshold. calculate.

  In these configurations, an oil leak sign based on the life of the rod seal 11 can be detected.

  In the fluid leak detection system 100, the controller 80 includes an information acquisition unit 85 that acquires operation information of the hydraulic cylinder 1 or a fluid pressure drive machine (construction machine) including the hydraulic cylinder 1, and the determination unit 84 includes: The operating time is calculated based on the operation information acquired by the information acquisition unit 85.

  Further, in the present embodiment, the fluid pressure drive machine is a construction machine, and the determination unit 84 acquires an on / off signal of an ignition switch for starting the construction machine as operation information, and the ignition switch is on. The operating time is calculated based on the accumulated time.

  In these configurations, in addition to the measurement result of the sensor unit 51, an indication of oil leakage based on the life of the rod seal 11 can be detected based on the operation information of the hydraulic cylinder 1 or the fluid pressure drive machine (construction machine). The oil leakage detection accuracy can be improved.

  In the fluid leak detection system 100, the measurement unit 10 measures at least one of pressure and temperature at a predetermined sampling period SC for each measurement cycle having a predetermined time length and repeated at predetermined time intervals. When at least one of pressure and temperature is measured by the transmission capacity Dc, which is a predetermined data capacity, the measurement result is transmitted to the controller 80, and the condition setting unit 83 repeats the measurement cycle time length and the measurement cycle as operating conditions. At least one of the time interval, the sampling cycle SC, and the transmission capacity Dc is changed.

  Further, in the fluid leak detection system 100, the measurement unit 10 includes the battery 54 as a power source, and the condition setting unit 83 determines a mode of changing the operation condition based on the remaining battery level of the battery 54.

  With this configuration, it is possible to achieve both improvement in detection accuracy of oil leakage and suppression of reduction in the life of the battery 54.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  DESCRIPTION OF SYMBOLS 1 ... Hydraulic cylinder (fluid pressure cylinder), 2 ... Cylinder tube, 3 ... Piston rod, 5 ... Cylinder head, 8 ... Annular gap (gap), 10 ... Measuring unit, 10a ... 1st measuring unit 10b ... 2nd measuring unit , 11 ... Rod seal, 50 ... Measuring unit, 54 ... Battery, 80 ... Controller, 83 ... Condition setting unit, 84 ... Judgment unit, 85 ... Information acquisition unit, 100 ... Fluid leak detection system

Claims (13)

Leakage of working fluid through a gap between the piston rod and the cylinder head in a hydraulic cylinder having a piston rod extending from the cylinder tube and a cylinder head through which the piston rod is inserted and provided in the cylinder tube A fluid leakage detection system for detecting
A measuring unit provided in the fluid pressure cylinder and measuring a state quantity of the working fluid leaking through the gap between the piston rod and the cylinder head;
A controller for obtaining a measurement result of the measurement unit,
The measurement unit is
A rod seal provided in the cylinder head for sealing the gap between the piston rod and the cylinder head;
A detection space into which the working fluid leaking from the rod seal is guided;
A measurement unit that performs measurement of the state quantity of the working fluid in the detection space and output of a measurement result under predetermined operation conditions,
The measurement unit is configured to be able to measure at least one of pressure and temperature of the detection space,
The controller is
A leakage determination unit that determines leakage of the working fluid based on the state quantity measured by the measurement unit;
A condition setting unit for setting the operating condition of the measurement unit;
A fluid leakage detection system comprising: a determination unit that determines whether or not to change the operating condition according to at least one of pressure and temperature measured by the measurement unit. The measurement unit is configured to measure pressure,
The fluid leakage detection system according to claim 1, wherein the determination unit determines a change in the operation condition by comparing pressure data obtained from the measurement result of the measurement unit in time series. . The measurement unit measures a pressure for each measurement cycle having a predetermined time length and repeated at predetermined time intervals,
The fluid leakage detection system according to claim 2, wherein the determination unit determines the change in the operating condition by comparing the pressure data that are moved back and forth in time series within the same measurement cycle. . The measurement unit measures a pressure for each measurement cycle having a predetermined time length and repeated at predetermined time intervals,
The determination unit compares the pressure data in the current measurement cycle input to the controller with the pressure data in the previous measurement cycle to determine a change in the operating condition. The fluid leakage detection system according to claim 2.   5. The determination unit according to claim 2, wherein the determination unit determines to change the operation condition if a difference between the pressure data moving back and forth in time series is equal to or greater than a predetermined difference threshold value. The fluid leak detection system described. The measurement unit includes a first measurement unit and a second measurement unit that are respectively provided in a pair of fluid pressure cylinders that drive the same drive target,
The fluid leakage detection system according to claim 1, wherein the determination unit compares the measurement result of the first measurement unit with the measurement result of the second measurement unit. .   When the determination unit determines that the operation condition is changed, the operation condition of the measurement unit in each of the first measurement unit and the second measurement unit is changed to the same condition. The fluid leak detection system according to claim 6.   The fluid leakage according to any one of claims 1 to 7, wherein the determination unit calculates an operation time of the fluid pressure cylinder and determines a change in the operation condition based on the operation time. Detection system. The measurement unit is configured to be able to measure temperature,
The fluid leakage detection system according to claim 8, wherein the determination unit calculates the operation time based on a measurement time when the measurement unit measures a temperature equal to or higher than a predetermined temperature threshold. The controller includes an information acquisition unit that acquires operation information of the fluid pressure cylinder or a fluid pressure driven machine including the fluid pressure cylinder,
The fluid leakage detection system according to claim 8, wherein the determination unit calculates the operation time based on the operation information acquired by the information acquisition unit. The fluid pressure driven machine is a construction machine,
The determination unit obtains an on / off signal of an ignition switch for starting the construction machine as the operation information, and calculates the operation time based on a cumulative time when the ignition switch is in an on state. The fluid leak detection system according to claim 10, wherein: The measurement unit measures at least one of pressure and temperature at a predetermined sampling period for each measurement cycle having a predetermined time length and repeated at predetermined time intervals, and only a transmission capacity as a predetermined data capacity. When measuring at least one of pressure and temperature, the measurement result is sent to the controller,
The condition setting unit changes, as the operation condition, at least one of a time length of the measurement cycle, a time interval at which the measurement cycle is repeated, the sampling period, and the transmission capacity. Item 12. The fluid leakage detection system according to any one of Items 1 to 11. The measurement unit has a battery as a power source,
The fluid leak detection system according to any one of claims 1 to 12, wherein the condition setting unit determines a mode of changing the operation condition based on a remaining battery level of the battery.

Images