JP2019130617A - Machine tool, coolant control method and computer program - Google Patents

Abstract

To provide a machine tool, a coolant control method and a computer program which can early detect occurrence of an abnormality in the machine tool to prevent the machine tool from being damaged.SOLUTION: The machine tool, which is provided with a plurality of sensors that are turned on in accordance with liquid level of coolants in a tank, comprises: a first monitoring part that monitors whether the plurality of sensors are turned on and off, and a stopping part that outputs a stop instruction for stopping operation of an own device when a monitored result by the first monitoring part shows that at least two sensors of the plurality of sensors are turned on.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a machine tool including a plurality of sensors that are turned on when a tank coolant reaches a predetermined liquid level, a coolant control method, and a computer program related to the machine tool.

  Machine tools perform many types of machining by automatically changing tools. The machine tool includes a tool storage unit and a tool changer. The tool storage unit stores a plurality of types of tools while being held in the tool holder, and sends out necessary tools to the replacement position. The tool changer receives the tool at the change position and then transports the tool to be mounted on the spindle to the change position, and attaches the tool to the spindle of the machine tool.

  The main shaft is located inside the machining chamber. Chips generated by the processing are present inside the processing chamber. Chips may adhere to the tool holder before being attached to the spindle. In this case, the tool cannot be correctly positioned with respect to the spindle due to the influence of chips. For example, the tool rotates in an eccentric state, and the machining accuracy decreases. The tool cannot be mounted on the spindle if the amount of chips attached is large.

  In order to solve such a problem, the machine tool ejects a cooling liquid (cleaning liquid) to the inside and outside of the tool at the time of machining operation and tool change. As a result, the chips adhering to the tool are washed away.

  For example, Patent Document 1 discloses a coolant filtering device that measures a coolant replenishment time to a clean tank and, when the required time is a predetermined time or more, determines that it is abnormal and notifies the user of the abnormality. It is disclosed. Thus, it is possible to notify the filter replacement time and the coolant tank cleaning time at an early stage.

JP 2002-231454 A

Many machine tools include a liquid level detection mechanism for detecting the liquid level in order to smoothly replenish the coolant. In a machine tool provided with a liquid level detection mechanism, failure of the liquid level detection mechanism, disconnection of an electric wire connecting the liquid level detection mechanism and the control unit, or the like may occur. As described above, when an abnormality relating to the liquid level detection mechanism occurs, there is a problem in that the pump that pumps up the coolant is idle, the coolant is excessively supplied to the tank, and the like.
However, such a problem cannot be solved by the coolant filtering device of Patent Document 1 described above.

  The present invention has been made in view of such circumstances, and an object of the present invention is to make it possible to detect the occurrence of an abnormality related to the liquid level detection mechanism at an early stage and prevent damage to such a machine tool in advance. To provide a machine, a coolant control method, and a computer program.

  The machine tool according to the present invention is a machine tool including a plurality of sensors that are turned on in accordance with a liquid level of a coolant in a tank, a first monitoring unit that monitors on / off of the plurality of sensors, and the first And a stop unit that outputs a stop instruction to stop the operation of the device when at least two of the plurality of sensors are turned on based on a monitoring result of the monitoring unit.

  In the present invention, the first monitoring unit monitors on / off of the plurality of sensors, and an abnormality occurs as in the case where at least two of the plurality of sensors are turned on. If there is such a possibility, the stop unit outputs the stop instruction, and the machine tool stops.

  In the machine tool according to the present invention, the plurality of sensors include at least three sensors that are sequentially turned on according to the order of the liquid level, and the three sensors are based on a monitoring result of the first monitoring unit. A second monitoring unit that monitors whether the switches are turned on sequentially is provided, and the stop unit outputs the stop instruction based on a monitoring result of the second monitoring unit.

  In the present invention, for example, when the second monitoring unit determines that the three sensors are not sequentially turned on, the stop unit outputs the stop instruction, and the machine tool stops.

  In the machine tool according to the present invention, the plurality of sensors include a first sensor that is turned on when the tank is at a full liquid level, and includes a pump that pumps the coolant from the tank. When the pump operates in the ON state, the stop unit outputs the stop instruction based on the monitoring result of the first monitoring unit with respect to the first sensor.

  In the present invention, when the first sensor is in an on state, that is, when the tank is in a full water level and the pump is operated, for example, after a predetermined time has elapsed, the first sensor is switched from on to off. If the first monitoring unit determines not to do so, the stop unit outputs the stop instruction.

  In the machine tool according to the present invention, when the coolant is supplied to the tank while the first sensor is off, the stop is performed based on a monitoring result of the second monitoring unit with respect to the first sensor. The unit outputs the stop instruction.

  In the present invention, when the coolant is supplied to the tank in a state where the first sensor is off, that is, in a state where the tank is not full, for example, after a predetermined time has elapsed, When the first monitoring unit determines that one sensor does not change from off to on, the stop unit outputs the stop instruction.

  In the machine tool according to the present invention, the plurality of sensors include a second sensor that is turned on when a predetermined amount of coolant is decreased from a full liquid level, and the second sensor is turned on, When supplying the coolant, the stop unit outputs the stop instruction based on the monitoring result of the first monitoring unit with respect to the second sensor.

  In the present invention, when the second sensor is on, that is, when a predetermined amount is not enough to reach the full water level of the tank, or when the coolant is supplied to the tank, for example, a certain time has elapsed. Thereafter, when the first monitoring unit determines that the second sensor does not change from on to off, the stop unit outputs the stop instruction.

  In the machine tool according to the present invention, the plurality of sensors include a third sensor that is turned on when no coolant remains in the tank, a pump that pumps the coolant from the tank, and a cooling that flows into the pump A pressure sensor for detecting the pressure of the liquid, and the stop unit outputs the stop instruction based on a detection result of the pressure sensor in a state where the third sensor is on.

  In the present invention, when the third sensor is off, that is, when the coolant does not remain in the tank, for example, when the detection result of the pressure sensor detects a predetermined pressure, the stop unit Outputs the stop instruction.

  The coolant control method according to the present invention is a coolant control method for controlling coolant in a machine tool including a plurality of sensors that are turned on when the coolant in the tank reaches a predetermined liquid level. The on / off state of the machine tool is monitored, and when at least two of the plurality of sensors are turned on based on the result of the monitoring, the operation of the machine tool is stopped.

  The computer program according to the present invention monitors on / off of a plurality of sensors that are turned on when the coolant in the tank of the machine tool reaches a predetermined liquid level by a computer, and based on the result of the monitoring, When at least two of the plurality of sensors are turned on, a process of outputting an instruction to stop the operation of the machine tool is executed.

  In the present invention, on / off of the plurality of sensors is monitored, and there is a possibility of occurrence of abnormality, such as when at least two of the plurality of sensors are both turned on. Outputs an instruction to stop the operation of the machine tool, and the machine tool stops.

  According to the present invention, since the occurrence of an abnormality in the coolant level detection can be detected at an early stage, damage to the machine tool due to the abnormality can be prevented in advance.

It is a block diagram which shows the principal part structure of the machine tool which concerns on this Embodiment. It is the schematic which shows the principal part structure of the float switch of the machine tool which concerns on this Embodiment. It is a schematic longitudinal cross-sectional view which shows the structure of the 1st tank and the 2nd tank in the machine tool which concerns on this Embodiment. It is a functional block diagram which shows the principal part structure of the control part of the machine tool which concerns on this Embodiment. It is a flowchart which shows an example of the response | compatibility with respect to the abnormality which concerns on the float switch in the machine tool which concerns on this Embodiment. It is a flowchart which shows the other example with respect to the abnormality which concerns on the float switch in the machine tool which concerns on this Embodiment. It is a flowchart which shows the other example with respect to the abnormality which concerns on the float switch in the machine tool which concerns on this Embodiment. It is a flowchart which shows the other example with respect to the abnormality which concerns on the float switch in the machine tool which concerns on this Embodiment.

Hereinafter, a machine tool, a coolant control method, and a computer program according to the present embodiment will be described with reference to the drawings.
FIG. 1 is a configuration diagram showing a main configuration of a machine tool according to the present embodiment. The machine tool 1 according to the present embodiment includes a first tank 20, a second tank 10, a first pump 70, and a second pump 60.

  The first tank 20 is a box-shaped container that primarily stores the dirty cleaning liquid used for processing the workpiece. The cleaning liquid stored in the first tank 20 is used as a cooling liquid for cleaning and cooling the workpiece and the tool. The second tank 10 stores a high-accuracy cleaning liquid, which will be described later, obtained by filtering the cleaning liquid in the first tank 20. Hereinafter, the cleaning liquid is also referred to as a cooling liquid.

  The machine tool 1 includes a first filter 71 that primarily filters the cleaning liquid in the first tank 20. The first pump 70 pumps up the cleaning liquid in the first tank 20 and sends it to the first filter 71. The second pump 60 pumps the high-precision cleaning liquid in the second tank 10 and sends it into the processing chamber 40.

  For example, the first filter 71 is a cyclone filter. The first filter 71 removes dirt such as chips in the cleaning liquid by a centrifugal separation process. The first filter 71 sends the cleaning liquid filtered through the centrifugal separation process to the storage tank 50. The first filter 71 sends the sewage containing the filth removed by the centrifugal separation process to the sewage container 72.

  The dirty liquid storage part 72 has a cylindrical shape, for example. The dirty liquid storage unit 72 receives and temporarily stores the dirty liquid discharged from the first filter 71. The dirty liquid storage part 72 discharges dirty liquid through a discharge port (not shown). The discharge port of the dirty liquid container 72 is connected to the discharge path 85. One end of the discharge path 85 is connected to the discharge port of the sewage container 72, and the other end opens to a bowl-shaped filter (not shown) provided inside the first tank 20.

  The discharge path 85 includes a discharge port valve 73. The control unit 9 to be described later controls the flow of sewage from the sewage storage unit 72 to the bowl-shaped filter by controlling the opening and closing of the discharge port valve 73.

  The first filter 71 sends the cleaning liquid filtered through the centrifugal separation process to the storage tank 50 via the first flow path 81. The first flow path 81 has one end connected to the first filter 71 and the other end connected to the storage tank 50. The first flow path 81 has a second filter 74. The first flow path 81 has a check valve 75 between the second filter 74 and the storage tank 50. The second filter 74 performs the filtration process again on the clean cleaning liquid from the first filter 71.

  Therefore, the cleaning liquid in the first tank 20 flows into the storage tank 50 after the primary filtration process in the first filter 71 and the secondary filtration process in the second filter 74. The storage tank 50 stores a cleaning liquid (hereinafter referred to as a high-precision cleaning liquid) that has undergone a primary filtration process and a secondary filtration process.

  A second flow path 82 is connected to the first flow path 81. One end of the second flow path 82 is connected between the check valve 75 and the storage tank 50, and the other end is connected to the nozzle 30 b in the processing chamber 40. Therefore, the nozzle 30b injects the high-precision cleaning liquid that has been filtered by the second filter 74 onto the tool and the workpiece. The second flow path 82 includes a second flow path valve 76. The controller 9 controls the flow of the high-precision cleaning liquid to the nozzle 30b by controlling the opening and closing of the second flow path valve 76.

  The storage tank 50 stores the high-precision cleaning liquid. The storage tank 50 is connected to the second tank 10 via the fourth flow path 83. The storage tank 50 is connected to an air source 80 for sending the high-precision cleaning liquid in the storage tank 50 to the second tank 10. The air source 80 is, for example, a compressor or the like, and pushes high-precision cleaning liquid in the storage tank 50 to the second tank 10 by sending high-pressure air to the storage tank 50.

  An air valve 86 is provided between the storage tank 50 and the air source 80. For example, the air source 80 constantly blows high-pressure air toward the storage tank 50, and the control unit 9 controls the supply of high-pressure air to the storage tank 50 by controlling the opening and closing of the air valve 86. For example, when the air valve 86 is opened, the high-precision cleaning liquid flows into the second tank 10 via the fourth flow path 83 due to the pressure of the high-pressure air.

  The fourth channel 83 has one end connected to the storage tank 50 and the other end opened at the second tank 10. The fourth flow path 83 includes a fourth flow path valve 51. The controller 9 controls the flow of the high-precision cleaning liquid from the storage tank 50 to the second tank 10 by controlling the opening and closing of the fourth flow path valve 51.

  The second pump 60 is disposed on the upper side of the second tank 10. The high-precision cleaning liquid in the second tank 10 is pumped up and sent to the processing chamber 40 via the fifth flow path 84. The fifth channel 84 has one end connected to the second pump 60 and the other end connected to the nozzle 30 a in the processing chamber 40. Therefore, the nozzle 30a injects the high-precision cleaning liquid pumped up by the second pump 60 onto the tool and workpiece being processed.

  The fifth flow path 84 includes a fifth flow path valve 67, and a line filter that filters the high-precision cleaning liquid is provided between the fifth flow path valve 67 and the second pump 60. The controller 9 controls the flow of the high-precision cleaning liquid to the nozzle 30a by controlling the opening and closing of the fifth flow path valve 67. Hereinafter, for convenience of description, the nozzle 30 a and the nozzle 30 b are also referred to as a nozzle 30.

  The storage tank 50 further includes a liquid level sensor 52 that detects the liquid level of the high-precision cleaning liquid stored in the storage tank 50. Based on the detection result of the liquid level sensor 52, the liquid level of the high-precision cleaning liquid in the storage tank 50, that is, the remaining amount can be confirmed.

  The second pump 60 has a pressure sensor 65 that detects the water pressure of the high-precision cleaning liquid pumped from the second tank 10. The pressure sensor 65 sends the detected result to the control unit 9.

A float switch 61 is disposed in the second tank 10. FIG. 2 is a schematic diagram showing a main configuration of the float switch 61 of the machine tool 1 according to the present embodiment.
The float switch 61 has a float F and a level tower T. The level tower T has a cylindrical shape and displays a level (memory) indicating the liquid level of the high-precision cleaning liquid in the second tank 10. The level tower T includes a disk-shaped permanent magnet M that slides along its inner peripheral surface. The permanent magnet M is connected to a rod-like float F via a shaft S. Therefore, when the float F moves up and down along with the change in the amount of high-precision cleaning liquid, the permanent magnet M moves up and down accordingly.

  The float switch 61 has three liquid level sensors attached to the outer peripheral surface of the level tower T at the low position, the middle position, and the high position along the height direction of the level tower T. Hereinafter, the liquid level sensor at the high position is referred to as the first sensor 62, the liquid level sensor at the middle position is referred to as the second sensor 63, and the liquid level sensor at the low position is referred to as the third sensor 64.

  The first sensor 62 to the third sensor 64 are so-called reed switches. When the permanent magnet M approaches, the first sensor 62 to the third sensor 64 are turned on by the magnetic field of the permanent magnet M. Thereby, the liquid level of the high-precision cleaning liquid in the second tank 10 can be measured. The first sensor 62 to the third sensor 64 transmit such measurement results to the control unit 9.

  When the first sensor 62 is in the on state, it indicates that the high-accuracy cleaning liquid is full. When the second sensor 63 is on, it indicates that the high-precision cleaning liquid has decreased by a predetermined amount from the full liquid level. When the third sensor 64 is in the on state, it indicates that no high-accuracy cleaning liquid remains.

  In the following, the case where the float switch 61 has three sensors of the first sensor to the third sensor will be described as an example, but the present embodiment is not limited to this. The float switch 61 may include three or more sensors.

  The second tank 10 is disposed above the first tank 20. FIG. 3 is a schematic longitudinal sectional view showing the configuration of the first tank 20 and the second tank 10 in the machine tool 1 according to the present embodiment.

  The second tank 10 and the first tank 20 have a casing shape, and are arranged so that the upper surface of the first tank 20 and the bottom surface of the second tank 10 are in contact with each other. The first tank 20 and the second tank 10 communicate with each other via the overflow pipe 11. The overflow pipe 11 has a cylindrical shape and projects in a direction intersecting the bottom surface of the second tank 10. The lower end of the overflow pipe 11 penetrates the bottom surface of the second tank 10 inward and outward, and penetrates the upper surface of the first tank 20 inward and outward.

  The overflow pipe 11 allows excess coolant to flow to the first tank 20 when the supply of coolant continues even though the second tank 10 is at the full liquid level. Therefore, it is possible to cope with the case where the supply of the cooling liquid to the second tank 10 cannot be controlled due to the failure of the liquid level sensor or the like.

  The second tank 10 is connected to the fourth flow path 83 via the flow path guide member 12. The flow path guide member 12 is a casing, and two partition walls 13 projecting in a direction intersecting with each inner side surface are provided on two inner side surfaces facing each other. The two partition walls 13 are alternately arranged in the vertical direction. The tip of the partition wall 13 protruding from one inner surface is separated from the other inner surface corresponding to the one inner surface by a predetermined distance.

  Accordingly, the coolant flowing into the flow path guide member 12 through the fourth flow path 83 enters the second tank 10 while forming an S-shaped flow path as shown in FIG. 3 (broken arrows in FIG. 3). reference). Therefore, the momentum of the coolant flowing from the fourth flow path 83 can be suppressed, and bubbles can be prevented from leaking out of the second tank 10 due to bubbles in the second tank 10.

  The machine tool 1 includes an instruction receiving unit 90 that receives an instruction to start and stop the machine machine 1 from a user. The instruction receiving unit 90 is, for example, a power switch. The instruction receiving unit 90 may be a power switch of a machine tool including the machine tool 1.

FIG. 4 is a functional block diagram showing a main configuration of the control unit 9 of the machine tool 1 according to the present embodiment.
The control unit 9 is a logic circuit having a CPU 91, a ROM (not shown), a RAM (not shown), and the like. The control unit 9 includes, for example, an FPGA (Field Programmable Gate Array) or an ASIC (Application Specific Integrated Circuit).

  The CPU 91 loads the control program stored in advance in the ROM onto the RAM and executes it, thereby controlling the various hardware described above and operating the entire apparatus as the machine tool 1 according to the present embodiment. Let

In addition, the control unit 9 includes a first monitoring unit 92, a second monitoring unit 93, a stop unit 94, a valve control unit 95, and a storage unit 96.
The first monitoring unit 92 monitors on / off of these liquid level sensors based on signals from the first sensor 62, the second sensor 63, and the third sensor 64. The second monitoring unit 93 monitors whether the first sensor 62, the second sensor 63, and the third sensor 64 are sequentially turned on or off based on the monitoring result of the first monitoring unit 92. For example, the second monitoring unit 93 sets a flag indicating whether any of the liquid level sensors is turned on in the RAM based on signals from the first sensor 62, the second sensor 63, and the third sensor 64. . Based on this, it is monitored whether the first sensor 62, the second sensor 63, and the third sensor 64 are turned on or turned off in this order (ascending order or descending order).

The stop unit 94 outputs an instruction to stop the operation of the machine tool 1 according to the present embodiment (hereinafter referred to as a stop instruction) based on the monitoring results of the first monitoring unit 92 and the second monitoring unit 93.
The valve control unit 95 controls opening / closing of the fourth flow path valve 51, the fifth flow path valve 67, the second flow path valve 76, and the air valve 86 in accordance with an instruction from the CPU 91.

The storage unit 96 is configured by a non-volatile storage medium such as a flash memory, EEPROM (registered trademark), HDD, MRAM (magnetic resistance memory), FeRAM (ferroelectric memory), or OUM, for example. The storage unit 96 stores a certain time used for determination to be described later.
The storage unit 96 includes at least one of the first sensor 62 to the third sensor 64 based on the process of monitoring on / off of the first sensor 62, the second sensor 63, and the third sensor 64, and the result of such monitoring. When both sensors are turned on, a computer program P or the like that executes processing for outputting a stop instruction for stopping the operation of the machine tool 1 may be stored.

  In a machine tool including the float switch 61, a failure of the float switch 61 itself, a breakage of an electric wire connecting the float switch 61 and the control unit 9, or the like may occur. As described above, when an abnormality relating to the float switch 61 occurs, there is a problem that the second pump 60 idles, the coolant is excessively supplied to the second tank 10, and the like.

  The machine tool 1 according to the present embodiment can cope with such a problem. This will be described below.

For example, it can be assumed that at least two of the first sensor 62, the second sensor 63, and the third sensor 64 are turned on. In view of the configuration of the float switch 61 as described above, both the liquid level sensors cannot be turned on, which is an abnormality related to the float switch 61.
In contrast, in the machine tool 1 according to the present embodiment, the first monitoring unit 92 monitors the on / off of the first sensor 62, the second sensor 63, and the third sensor 64, and the first monitoring unit 92. When the CPU 91 determines that both of the two or more liquid level sensors are turned on based on the monitoring result, the stop unit 94 outputs the stop instruction. Therefore, the operation of the machine tool 1 is quickly stopped.

  FIG. 5 is a flowchart showing an example of a response to the abnormality related to the float switch 61 in the machine tool 1 according to the present embodiment. In FIG. 5, for convenience of explanation, the case where the high-precision cleaning liquid gradually decreases from the full liquid level in the second tank 10 will be described as an example.

  When the second tank 10 is full, the first sensor 62 is turned on (step S101). The first sensor 62 transmits that fact to the control unit 9. Receiving the signal from the first sensor 62, the CPU 91 instructs the fourth flow path valve 51 and the air valve 86 to stop supplying the coolant (step S102). In response to an instruction from the CPU 91, the fourth flow path valve 51 and the air valve 86 are closed, and the supply of the coolant to the second tank 10 is stopped.

  Next, the CPU 91 determines whether or not there is an operation of the second pump 60 (step S103). That is, the CPU 91 determines whether the second pump 60 has already started operation or whether it will start operation from now.

  When it is determined that the second pump 60 is not operating (step S103: NO), the CPU 91 repeats such determination after a predetermined time has elapsed. When the CPU 91 determines that there is an operation of the second pump 60 (step S103: YES), the first monitoring unit 92 determines whether any other liquid level sensor is turned on (step S104).

  When it is determined that any other liquid level sensor is not turned on (step S104: NO), the first monitoring unit 92 repeats such determination after a predetermined time has elapsed. When the first monitoring unit 92 determines that any other liquid level sensor is turned on (step S104: YES), the second monitoring unit 93 includes the first sensor 62, the second sensor 63, and the third sensor 64. It is determined whether or not the order is satisfied (step S105). The determination method of the second monitoring unit 93 has already been described, and a description thereof will be omitted.

  As in the above premise, the example according to FIG. 5 is a case where the high-precision cleaning liquid gradually decreases from the full liquid level. Therefore, after the first sensor 62 is turned on, the second sensor 63 is turned on. Should be, and this is in order. Accordingly, the second monitoring unit 93 determines that the order is in order when the second sensor 63 is turned on, and determines that the order is not in order when the third sensor 64 is turned on.

When it is determined that the second monitoring unit 93 does not follow the order (step S105: NO), since there is a high possibility of an abnormality relating to the float switch 61, the stop unit 94 outputs the stop instruction (step S106). . Thereafter, the operation of the machine tool 1 is quickly stopped. After stopping such operation, the user may be notified.
When it is determined that the second monitoring unit 93 is in order (step S105: YES), the process ends with no abnormality.

  FIG. 6 is a flowchart showing another example of the response to the abnormality related to the float switch 61 in the machine tool 1 according to the present embodiment. In FIG. 6, for convenience of explanation, processing based mainly on on / off of the first sensor 62 will be described as an example.

  The first monitoring unit 92 determines whether or not the first sensor 62 is on (step S201). If the first monitoring unit 92 determines that the first sensor 62 is on (step S201: YES), that is, if the second tank 10 is full, is the CPU 91 operating in the second pump 60? It is determined whether or not (step S202). That is, the CPU 91 determines whether the second pump 60 has already started operation or whether it will start operation from now.

  When it is determined that the second pump 60 is not operating (step S202: NO), the CPU 91 instructs the fourth flow path valve 51 and the air valve 86 to stop supplying the coolant (step S206). In response to an instruction from the CPU 91, the fourth flow path valve 51 and the air valve 86 are closed, and the supply of the coolant to the second tank 10 is stopped. Thereafter, the process returns to step S201.

  When the CPU 91 determines that there is an operation of the second pump 60 (step S202: YES), the CPU 91 instructs the time measuring unit (not shown) to measure a certain time. The CPU 91 determines whether or not the predetermined time has elapsed based on the timing result of the timing unit (step S203). The predetermined time is, for example, the time taken for the high-precision cleaning liquid to decrease from the liquid level corresponding to the first sensor 62 to the liquid level corresponding to the second sensor 63.

  When the CPU 91 determines that the predetermined time has not elapsed (step S203: NO), the CPU 91 repeats such determination until the predetermined time elapses. When the CPU 91 determines that the predetermined time has elapsed (step S203: YES), the first monitoring unit 92 determines whether or not the first sensor 62 has changed from on to off (step S204). That is, when the second pump 60 operates for a certain time, the high-accuracy cleaning liquid in the second tank 10 decreases by a predetermined amount, so it is confirmed whether this is detected.

  When the 1st monitoring part 92 determines that the 1st sensor 62 changed from ON to OFF (step S204: YES), a process returns to step S201. When the first monitoring unit 92 determines that the first sensor 62 has not changed from on to off (step S204: NO), the possibility of an abnormality relating to the float switch 61 is high, so the stop unit 94 stops the stop. An instruction is output (step S205). Thereafter, the operation of the machine tool 1 is quickly stopped.

  When the 1st monitoring part 92 determines that the 1st sensor 62 is not ON (step S201: NO), ie, when the 2nd tank 10 is not a full liquid level, CPU91 determines whether there exists cooling fluid supply. (Step S207). The CPU 91 makes such a determination by checking whether or not the fourth flow path valve 51 and the air valve 86 are open.

  When it is determined that there is no coolant supply (step S207: NO), the CPU 91 instructs the fourth flow path valve 51 and the air valve 86 to execute coolant supply (step S210). In response to an instruction from the CPU 91, the fourth flow path valve 51 and the air valve 86 are opened, and supply of the coolant to the second tank 10 is started. Thereafter, the process returns to step S201.

  If the CPU 91 determines that there is coolant supply (step S207: YES), the CPU 91 instructs the timekeeping unit to measure a certain time. The CPU 91 determines whether or not the predetermined time has elapsed based on the timing result of the timing unit (step S208). Here, the predetermined time is, for example, the time taken for the high-precision cleaning liquid to increase from the liquid level corresponding to the second sensor 63 to the liquid level corresponding to the first sensor 62.

  If the CPU 91 determines that the certain time has not elapsed (step S208: NO), the CPU 91 repeats such determination until the certain time has elapsed. When the CPU 91 determines that the predetermined time has elapsed (step S208: YES), the first monitoring unit 92 determines whether or not the first sensor 62 has switched from OFF to ON (step S209). That is, when the coolant supply is performed for a certain period of time, the high-accuracy cleaning liquid in the second tank 10 increases by a predetermined amount to reach the full liquid level, so it is confirmed whether this is detected.

  When the 1st monitoring part 92 determines that the 1st sensor 62 changed from OFF to ON (step S209: YES), a process returns to step S201. If the first monitoring unit 92 determines that the first sensor 62 has not changed from OFF to ON (step S209: NO), the stop unit 94 stops the stop because the possibility of an abnormality relating to the float switch 61 is high. An instruction is output (step S205).

  FIG. 7 is a flowchart showing another example of the response to the abnormality related to the float switch 61 in the machine tool 1 according to the present embodiment. In FIG. 7, for convenience of explanation, processing based mainly on on / off of the second sensor 63 will be described as an example.

  The first monitoring unit 92 determines whether or not the second sensor 63 is on (step S301). If the first monitoring unit 92 determines that the second sensor 63 is not on (step S301: NO), for example, if the liquid level in the second tank 10 is higher than the liquid level corresponding to the second sensor 63, the process is stepped. Return to S301.

  When the first monitoring unit 92 determines that the second sensor 63 is on (step S301: YES), the CPU 91 determines whether there is a coolant supply (step S302). When determining that there is no coolant supply (step S302: NO), the CPU 91 instructs the fourth flow path valve 51 and the air valve 86 to execute coolant supply (step S306). In response to an instruction from the CPU 91, the fourth flow path valve 51 and the air valve 86 are opened, and supply of the coolant to the second tank 10 is started. Thereafter, the process returns to step S301.

  When the CPU 91 determines that there is a coolant supply (step S302: YES), the CPU 91 instructs the time measuring unit to measure a certain time. The CPU 91 determines whether or not the predetermined time has elapsed based on the timing result of the timing unit (step S303). Here, the predetermined time is, for example, the time taken for the high-precision cleaning liquid to increase from the liquid level corresponding to the second sensor 63 to the liquid level corresponding to the first sensor 62.

  When the CPU 91 determines that the certain time has not elapsed (step S303: NO), the CPU 91 repeats such determination until the certain time has elapsed. When the CPU 91 determines that the predetermined time has elapsed (step S303: YES), the first monitoring unit 92 determines whether or not the second sensor 63 is switched from on to off (step S304). That is, when the coolant supply is executed for a certain time, the high-accuracy cleaning liquid in the second tank 10 increases by a predetermined amount and becomes higher than the liquid level corresponding to the second sensor 63, so it is confirmed whether this is detected. .

  When the 1st monitoring part 92 determines that the 2nd sensor 63 changed from ON to OFF (step S304: YES), a process returns to step S301. When the first monitoring unit 92 determines that the second sensor 63 has not changed from on to off (step S304: NO), the possibility of an abnormality relating to the float switch 61 is high, so the stop unit 94 stops the stop. An instruction is output (step S305). Thereafter, the operation of the machine tool 1 is quickly stopped.

  FIG. 8 is a flowchart showing another example of the response to the abnormality related to the float switch 61 in the machine tool 1 according to the present embodiment. In FIG. 8, for convenience of explanation, processing based mainly on on / off of the third sensor 64 will be described as an example.

  Based on the detection result of the pressure sensor 65, the CPU 91 determines whether or not the water pressure of the high-accuracy cleaning liquid pumped from the second tank 10 by the second pump 60 has been detected (step S401). When the CPU 91 determines that the water pressure of the high-precision cleaning liquid cannot be detected (step S401: NO), the first monitoring unit 92 determines whether the third sensor 64 is on (step S402). The fact that the water pressure of the high-precision cleaning liquid cannot be detected by the pressure sensor 65 is that the second pump 60 has not been able to pump up the high-precision cleaning liquid and there is no remaining amount of the high-precision cleaning liquid in the second tank 10. . In step S402, it is confirmed whether the third sensor 64 can detect this.

  If the first monitoring unit 92 determines that the third sensor 64 is on (step S402: YES), the third sensor 64 is normal, but there is no remaining amount of high-precision cleaning liquid, so the CPU 91 causes the second pump An instruction to stop 60 is output to the second pump 60. The second pump 60 stops in response to the instruction from the CPU 91 (step S403).

  If the first monitoring unit 92 determines that the third sensor 64 is not on (step S402: NO), the CPU 91 causes the third sensor 64 to be abnormal because there is a high possibility of an abnormality relating to the float switch 61 (third sensor 64). The failure information indicating that has failed is output (step S404). Next, the stop unit 94 outputs the stop instruction (step S405). Based on the failure information, a display unit (not shown) may display a predetermined message, sound a warning sound, or turn on a warning lamp. Thereafter, the operation of the machine tool 1 is quickly stopped.

  If the CPU 91 determines in step S401 that the water pressure of the high-precision cleaning liquid has been detected (step S401: YES), the first monitoring unit 92 determines whether or not the third sensor 64 is on (step S406). ). The fact that the water pressure of the high-precision cleaning liquid can be detected by the pressure sensor 65 means that the second pump 60 has pumped up the high-precision cleaning liquid. is there. In step S406, it is confirmed whether the third sensor 64 can detect this.

  If the first monitoring unit 92 determines that the third sensor 64 is not on (step S406: NO), the third sensor 64 is operating normally, and the process returns to step S401. If the first monitoring unit 92 determines that the third sensor 64 is ON (step S406: YES), the process proceeds to step S404 because there is a high possibility of an abnormality relating to the float switch 61 (third sensor 64). The CPU 91 outputs the failure information (step S404), and the stop unit 94 outputs the stop instruction (step S405).

  Since it has the above configuration, the machine tool 1 according to the present embodiment can quickly detect the occurrence of an abnormality related to the float switch 61, and can quickly stop the operation of the machine tool 1, thereby causing the problems described above. Can be prevented in advance.

  In the above description, the case where the first sensor 62, the second sensor 63, and the third sensor 64 are provided in the float switch 61 is described as an example. However, the present invention is not limited to this. The first sensor 62, the second sensor 63, and the third sensor 64 may be provided directly on the second tank 10 so as to detect the liquid level of the high-precision cleaning liquid.

DESCRIPTION OF SYMBOLS 1 Machine tool 10 2nd tank 60 2nd pump 61 Float switch 62 1st sensor 63 2nd sensor 64 3rd sensor 65 Pressure sensor 91 CPU
92 1st monitoring part 93 2nd monitoring part 94 Stopping part

Claims (8)

In a machine tool provided with a plurality of sensors that are turned on according to the liquid level of the coolant in the tank,
A first monitoring unit that monitors on / off of the plurality of sensors;
A stop unit that outputs a stop instruction to stop the operation of the device when at least two of the plurality of sensors are turned on based on a monitoring result of the first monitoring unit. A featured machine tool. The plurality of sensors includes at least three sensors that are sequentially turned on according to the order of the liquid level,
A second monitoring unit that monitors whether the three sensors are sequentially turned on based on a monitoring result of the first monitoring unit;
The machine tool according to claim 1, wherein the stop unit outputs the stop instruction based on a monitoring result of the second monitoring unit. The plurality of sensors includes a first sensor that is turned on when the tank is full.
A pump for pumping coolant from the tank;
The said stop part outputs the said stop instruction | indication based on the monitoring result of the said 1st monitoring part with respect to the said 1st sensor, when the said pump operate | moves in the state where the said 1st sensor is on. 2. The machine tool according to 2.   When supplying the coolant to the tank in a state where the first sensor is off, the stop unit outputs the stop instruction based on a monitoring result of the second monitoring unit with respect to the first sensor. The machine tool according to claim 3. The plurality of sensors includes a second sensor that is turned on when a predetermined amount of coolant is reduced from the full liquid level,
When supplying the coolant to the tank with the second sensor on, the stop unit outputs the stop instruction based on the monitoring result of the first monitoring unit with respect to the second sensor. The machine tool according to claim 1 or 2, characterized in that The plurality of sensors includes a third sensor that is turned on when no coolant remains in the tank;
A pump for pumping coolant from the tank;
A pressure sensor for detecting the pressure of the coolant flowing into the pump,
3. The machine tool according to claim 1, wherein the stop unit outputs the stop instruction based on a detection result of the pressure sensor in a state where the third sensor is turned on. In a machine tool having a plurality of sensors that are turned on when the coolant in the tank reaches a predetermined liquid level, a coolant control method for controlling the coolant,
Monitoring on / off of the plurality of sensors;
A coolant control method comprising: stopping operation of the machine tool when at least two of the plurality of sensors are turned on based on a result of the monitoring. At the computer
Monitors on / off of multiple sensors that are turned on when the coolant in the tank of the machine tool reaches a predetermined liquid level,
A computer program for executing processing for outputting an instruction to stop the operation of the machine tool when both of the plurality of sensors are turned on based on the monitoring result.

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