JP6331474B2 - Machine tool cleaning fluid filtration device - Google Patents

Description

  The present invention relates to a cleaning liquid filtering device for filtering a cleaning liquid used in a 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, conveys it, and attaches it to the spindle of the machine tool. The tool changer removes the used tool from the spindle, conveys it to the change position, and returns it to the tool storage unit.

  The tool holder includes a spindle mounting part and a tool holding part. The main shaft mounting portion has a conical shape. The tool holding unit holds tools such as a drill and a tap. The spindle has a tool mounting hole. The tool mounting hole is a conical hole corresponding to the spindle mounting portion. The spindle is provided with a pulling rod at the back of the tool mounting hole. The tool changer fits the spindle mounting portion of the tool holder into the tool mounting hole. The pulling rod grips and lifts the end of the main shaft mounting portion, and fixes the tool holder to the main shaft. The spindle mounting part closely contacts the tool mounting hole to position the spindle and the tool concentrically.

  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. The adhering chips enter between the spindle mounting part and the tool mounting hole. The tool cannot be positioned correctly with respect to the spindle due to the influence of chips. The tool rotates in an eccentric state, and machining accuracy decreases. The tool cannot be mounted on the spindle if the amount of chips attached is large. The operator needs to stop the machining and remove the chips.

  The machine tool described in Patent Document 1 includes a tool cleaning device. The tool cleaning device cleans the tool and the tool holder before attaching to the spindle. The tool cleaning apparatus includes a cleaning nozzle that ejects cleaning liquid to the tip of the main shaft. The cleaning nozzle is connected to a cleaning liquid supply source for supplying a cleaning liquid and an air pressure source. The cleaning liquid also serves as a cooling liquid for cooling the tool being processed and the workpiece.

  The cleaning liquid supply source includes a tank that stores the cleaning liquid and a pump that delivers the cleaning liquid. The pump passes the cleaning liquid in the tank to the cleaning nozzle through a pipe. An air pressure source sends air to the pipe in the vicinity of the cleaning nozzle. Therefore, the cleaning liquid is ejected from the cleaning nozzle at a high speed by the action of air. The cleaning liquid strikes the tool and the tool holder vigorously to wash away the chips.

  A filter is provided near the inlet of the pump. The cleaning liquid in the tank contains chips. The filter filters the cleaning liquid sucked into the pump and captures chips.

JP 2011-83874 A

  The filter is clogged by continuing filtration of the cleaning liquid. In order to eliminate clogging of the filter, the cleaning solution is flowed in the opposite direction. In order to flow the cleaning liquid in the reverse direction, a reverse flow tank for storing the cleaning liquid, a liquid supply pipe connected to the reverse flow tank, and a switching valve for switching the connection destination of the pump to the cleaning nozzle or the reverse flow tank are newly provided. After the connection destination of the pump is switched to the backflow tank, the pump rotates backward. The cleaning liquid in the backflow tank passes through the liquid supply pipe, piping and pump and reaches the filter. The cleaning liquid flows through the filter in the opposite direction, and the clogging of the filter is eliminated.

  However, in order to install the backflow tank, it is necessary to secure a large space in advance. In addition, the new structure (backflow tank, liquid feed pipe, and switching valve) through which the cleaning liquid flows is complicated.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a machine tool cleaning liquid filtering device that eliminates clogging of a filter with a simple configuration without securing a large space.

  A cleaning liquid filtering device for a machine tool according to the present invention includes a tank for storing a cleaning liquid, a cleaning nozzle for ejecting the cleaning liquid to a tool, the cleaning nozzle and the tank are connected, and the cleaning liquid in the tank is supplied to the cleaning nozzle. A cleaning liquid passage for a machine tool, comprising a cleaning liquid passage, a pump that is interposed in the cleaning liquid passage, sends the cleaning liquid in the tank to the cleaning nozzle, and a filter that is disposed on the suction port side of the pump The apparatus is characterized by comprising a pressurizing passage connected to the cleaning liquid passage between the filter and the suction port of the pump and pressurizing the inside of the cleaning liquid passage with air.

  In the present invention, in the cleaning liquid passage, air is supplied from the pressure passage between the filter and the suction port of the pump to pressurize. The cleaning liquid in the cleaning liquid passage existing between the filter and the suction port of the pump moves to the filter side by air pressure. The cleaning liquid flows through the filter in the opposite direction, and the clogging of the filter is eliminated.

  A cleaning liquid filtering device for a machine tool according to the present invention is interposed in the pressurizing passage, and is a switching valve that switches supply or stop of supply of air to the cleaning liquid passage, and closer to the cleaning liquid passage than the switching valve. And a check valve that prevents backflow of air to the switching valve side, and the pressurization path between the check valve and the cleaning liquid passage includes the check valve. It is longer than the pressurization path between the valve and the switching valve.

  In the present invention, when the cleaning liquid is sent from the pump to the cleaning nozzle, the cleaning liquid is stored between the check valve and the cleaning liquid passage in the pressurizing path. When the cleaning liquid is sent from the pump to the cleaning nozzle, the check valve is closed, so that air accumulates between the check valve and the switching valve in the pressurizing path. In the pressurization path, the distance between the check valve and the cleaning liquid passage is longer than the distance between the check valve and the switching valve, so that the amount of cleaning liquid stored in the pressurization path increases. Therefore, the amount of the cleaning liquid flowing in the reverse direction increases, and the clogging of the filter is surely eliminated.

  In the cleaning liquid filtering device for a machine tool according to the present invention, the switching valve is opened and closed by air pressure, and an air supply path connecting the switching valve and an air pressure source is interposed in the air supply path. And an air supply valve.

  In the present invention, a valve that opens and closes by air pressure is used as the switching valve. Compared with the use of a solenoid valve, a valve that opens and closes by air pressure is less likely to fail. In addition, the structure is simple and easy to handle.

  In the machine tool cleaning liquid filtering apparatus according to the present invention, the pump is a gear pump.

  In the present invention, a gear pump is used as a pump for sending the cleaning liquid to the cleaning nozzle. A gear pump has a larger suction force than other pumps (for example, a pump using an impeller). After the cleaning liquid accumulated between the check valve and the cleaning liquid passage in the pressurizing passage flows back through the filter, the space between the check valve and the cleaning liquid passage becomes empty. By rotating the gear pump forward, the space between the vacant check valve and the cleaning liquid passage can be quickly filled with the cleaning liquid.

  In the present invention, in the cleaning liquid passage, air is supplied from the pressure passage between the filter and the suction port of the pump to pressurize. The cleaning liquid in the cleaning liquid passage existing between the filter and the suction port of the pump moves to the filter side by air pressure. The cleaning liquid flows through the filter in the opposite direction, and the clogging of the filter is eliminated. The cleaning liquid filter is installed in the factory. The factory already has an air source. Since the pressurizing path is connected to the air source, a large structure is not necessary. Further, it is not necessary to provide a backflow tank for storing the cleaning liquid, and it is not necessary to secure a large space. Moreover, it is not necessary to newly provide a complicated structure through which the cleaning liquid flows.

It is a perspective view of a machine tool provided with a washing fluid filtration device. FIG. 3 is a front view schematically showing a configuration near a spindle and a spindle head. FIG. 3 is a right side view schematically showing a configuration near a spindle and a spindle head. It is the figure which looked at the structure of the spindle and the vicinity of the spindle head from below. It is principal part sectional drawing of the structure of a spindle and spindle head vicinity. It is a hydraulic-pressure circuit diagram of a washing liquid filtration apparatus.

  Hereinafter, the present invention will be described based on the drawings showing a machine tool according to an embodiment. In the following description, up and down, left and right, and front and rear indicated by arrows in the figure are used. The front corresponds to the front and the back corresponds to the rear. FIG. 1 is a perspective view of a machine tool including a cleaning liquid filtering device, FIG. 2 is a front view schematically showing the configuration near the spindle and the spindle head, and FIG. 3 is a right side view schematically showing the configuration near the spindle and the spindle head. .

  As shown in FIGS. 1 and 2, the machine tool 1 includes a control box 3 and a column 4 on a base 2 supported on a floor surface. The operator operates the machine tool 1 from the front side. The column 4 is a support column that stands vertically at the center in the left-right direction at the rear of the base 2. The machine tool 1 includes a processing chamber on the front side of the column 4. The processing chamber includes a processing table (not shown) that is movable in the front-rear and left-right directions. The machine tool 1 processes a workpiece on a processing table.

  The column 4 supports the spindle head 5 at the front. The spindle head 5 moves up and down along the column 4. The control box 3 is attached to the rear side of the column 4. The control box 3 accommodates a control unit (not shown) inside. The machine tool 1 has an operation panel (not shown). The operator operates the operation panel and inputs a command to the control unit.

  As shown in FIG. 2, the spindle head 5 has a spindle 6 at the bottom and a drive mechanism 7 at the top. The spindle head 5 is raised and lowered by the drive of the drive mechanism 7. The main shaft 6 rotates about the vertical axis.

  The machine tool 1 includes an ATC (automatic tool changer) 8. As shown in FIGS. 2 and 3, the ATC 8 includes a tool storage portion 17 and a tool change mechanism 18. The tool storage portion 17 is provided on the right side of the spindle head 5. The tool change mechanism 18 is provided between the spindle head 5 and the tool storage unit 17.

  As shown in FIG. 3, the tool storage portion 17 includes a plurality of tool pods 15 attached to the chain 16. The tool pod 15 holds a tool holder 21 (see FIG. 5) to which the tool body 20 is attached. The tool pod 15 moves as the chain 16 circulates, and conveys the tool body 20 and the tool holder 21 to the replacement position (lower position in FIG. 3). At the replacement position, the tool pod 15 sends the tool body 20 and the tool holder 21 out of the tool storage unit 17. The tool body 20 and the tool holder 21 constitute a tool.

  FIG. 4 is a view of the configuration near the spindle and the spindle head as viewed from below. The tool change mechanism 18 includes an exchange arm 18a. The exchange arm 18a pivots about an axis parallel to the main shaft 6 and moves up and down. The exchange arm 18a has grips 18b at both ends. The gripping portion 18b moves to the lower position of the main shaft 6 and the replacement position of the tool storage portion 17 as the replacement arm 18a turns. The gripping portion 18b grips the tool holder 21 at the replacement position. The other gripping portion 18 b grips the tool holder 21 at a position below the main shaft 6.

  The exchange arm 18 a is lowered while holding the tool holder 21, and removes the tool body 20 and the tool holder 21 from the tool pod 15 and the main shaft 6. The exchange arm 18a turns 180 ° after being lowered. The tool body 20 and the tool holder 21 move from the replacement position to the lower position of the main shaft 6 or from the lower position of the main shaft 6 to the replacement position. The exchange arm 18a rises after turning, and the tool body 20 and the tool holder 21 are fitted into the main shaft 6 or the tool pod 15.

  FIG. 5 is a cross-sectional view of the main part of the configuration near the spindle and the spindle head. The tool holder 21 includes a spindle mounting portion 21a and a tool holding portion 21b. The tool holding part 21b has two cylindrical parts with different diameters. The lower cylindrical portion grips the tool body 20. The diameter of the upper cylindrical part is larger than the diameter of the lower cylindrical part. The main shaft mounting portion 21a is a conical portion continuous with the upper surface of the upper cylindrical portion.

  The main shaft 6 is provided with a tool mounting hole 19 opened on the lower surface. The tool mounting hole 19 is a conical hole corresponding to the spindle mounting portion 21a. The tool holder 21 is attached to the main shaft 6 by fitting the main shaft mounting portion 21 a into the tool mounting hole 19. The tool holder 21 is positioned by bringing the spindle mounting portion 21a into close contact with the tool mounting hole 19 and bringing the upper end surface 21c of the tool holding portion 21b into close contact with the lower surface of the spindle 6.

  The spindle head 5 supports the spindle 6 so as to be rotatable around the axis. The spindle head 5 includes an annular spindle cap 22 at the lower end. The spindle cap 22 is fixed to the lower surface of the spindle head 5 with a plurality of bolts 23. The lower surface of the main shaft 6 is exposed from the center hole of the main shaft cap 22. A space between the lower surface of the main shaft 6 and the main shaft cap 22 is closed by an annular end surface cover 24. The end surface cover 24 is fixed to the lower surface of the main shaft 6 so as to contact the lower surface of the main shaft cap 22.

  The tool body 20 rotates with the main shaft 6. The tool body 20 moves up and down together with the spindle head 5. The tool body 20 processes a workpiece on a processing table in the processing chamber. The workpiece moves in the front-rear direction and the left-right direction together with the processing table.

  The machine tool 1 includes a cleaning liquid filtering device 10. The cleaning liquid filtering device 10 cleans the tool body 20 and the tool holder 21 before attaching them to the main shaft 6. The main shaft cap 22 has an annular groove 25 on the lower surface. The annular groove 25 is formed outside the outer periphery of the end surface cover 24. The annular groove 25 is closed by an annular nozzle forming member 26 attached to the lower surface of the spindle cap 22. The nozzle forming member 26 has an annular nozzle hole 29 opened on the lower surface. The lower surface of the nozzle forming member 26 is substantially the same height as the lower end surface of the main shaft 6. The nozzle hole 29 is formed obliquely toward the center of the spindle head 5 and the spindle 6.

  The annular groove 25 continues to a liquid supply hole 27 provided in the main shaft cap 22. The liquid supply hole 27 opens to the outer periphery of the spindle cap 22. The liquid supply hole 27 is connected to the cleaning liquid hose 28. The cleaning liquid hose 28 supplies the cleaning liquid A. The cleaning liquid A enters the annular groove 25 through the liquid supply hole 27 and is ejected from the nozzle hole 29. As shown in FIG. 5, the cleaning liquid A is ejected in the direction of the nozzle hole 29 to clean the tool holder 21 and the tool body 20 located below the main shaft 6. The nozzle forming member 26 and the nozzle hole 29 constitute a cleaning nozzle 30. The annular groove 25, the liquid supply hole 27, and the cleaning liquid hose 28 constitute a part of the cleaning liquid supply path.

  As shown in FIG. 1, the machine tool 1 includes a cleaning liquid filtering device 10. The cleaning liquid filtering device 10 includes a tank 11 and a gear pump 40. The tank 11 is a box-shaped container and contains a cooling liquid (cleaning liquid A) supplied into the processing chamber. The gear pump 40 is installed on the tank 11.

  The cleaning liquid filtering device 10 can be attached to and detached from the rear side of the base 2. FIG. 1 shows a state where the cleaning liquid filtering device 10 is removed. The tank 11 can be connected to a discharge part 2a on the rear side of the base 2 (see FIG. 1). The tank 11 collects the used cooling liquid (cleaning liquid A) collected in the discharge part 2a through a filtration device (not shown).

  The gear pump 40 sucks the cooling liquid (cleaning liquid A) in the tank 11 and sends it out to the processing chamber. The gear pump 40 is a pump for both cooling liquid and cleaning liquid. The discharge side of the gear pump 40 is connected to one end of a coolant pipe (not shown). The coolant pipe extends into the processing chamber. The cooling liquid is ejected into the processing chamber from a cooling liquid nozzle (not shown) provided at the other end of the cooling liquid pipe. The cooling liquid cools the tool and workpiece being processed in the processing chamber. The coolant may be used for the main shaft 6 and the tool provided with a flow path and ejected from the tip of the tool.

  FIG. 6 is a hydraulic circuit diagram of the cleaning liquid filtering device 10. The first liquid supply pipe 51 (cleaning liquid passage) connects the tank 11 and the suction port 44 of the gear pump 40. A filter 12 is provided on the tank 11 side of the first liquid feeding pipe 51. The filter 12 is located in the tank 11.

  The second liquid feeding pipe 52 and the cleaning liquid hose 28 connect the cleaning nozzle 30 and the discharge port 47 of the gear pump 40. One end of each of the second liquid feeding pipe 52 and the cleaning liquid hose 28 is connected via an injection valve 55. The other end of the second liquid feeding pipe 52 is connected to the discharge port 47 of the gear pump 40. The other end of the cleaning liquid hose 28 is connected to the cleaning nozzle 30. The injection valve 55 has an elastic member and opens and closes by the elastic force and air pressure of the elastic member.

  The second liquid feeding pipe 52 is provided with a check valve 54 for preventing the cleaning liquid A from flowing back to the gear pump 40 side. A pressure gauge 53 is provided between the check valve 54 and the injection valve 55 in the second liquid feeding pipe 52. The pressure gauge 53 measures the discharge pressure of the gear pump 40. The value of the pressure gauge 53 is input to the control unit. When the filter 12 is clogged, the value of the pressure gauge 53 is smaller than the normal value. When the value of the pressure gauge 53 is smaller than the normal value, the control unit notifies that fact. For example, a lamp (not shown) is turned on, a warning is displayed on a screen (not shown), or a warning sound is emitted from a speaker (not shown).

  The gear pump 40 includes a gear mechanism 41, a motor 42, a return pipe 45, and a pressure control valve 46. The gear mechanism 41 has, for example, two external gears. The motor 42 rotates based on a command from the control unit. The motor 42 is connected to the gear mechanism 41. The gear mechanism 41 is connected to the suction port 44 via the first liquid feeding pipe 51. The gear mechanism 41 is connected to the discharge port 47 via the pipe 43. When the motor 42 rotates, the gear mechanism 41 rotates and sends the cleaning liquid A from the suction port 44 to the discharge port 47. The gear mechanism 41 may use an internal gear instead of the external gear.

  Instead of the gear pump 40, another type of pump may be used. For example, a vane pump, screw pump, plunger pump, centrifugal pump, mixed flow pump, axial flow pump, or the like may be used.

  One end of the return pipe 45 is connected to the pipe 43, and the other end is connected to the tank 11. The pressure control valve 46 is provided in the return pipe 45. The pressure control valve 46 has an elastic member and is closed by the elastic force of the elastic member. When the pressure in the pipe 43 exceeds a predetermined value, the pressure control valve 46 opens against the elastic force of the elastic member. By opening the pressure control valve 46, the pressure acting on the pipe 43 is lowered, and damage to the pipe 43 can be prevented. The first liquid supply pipe 51, the second liquid supply pipe 52, and the pipe 43 constitute a cleaning liquid passage.

  The pressurizing path 60 connects the first liquid feeding pipe 51 and the pneumatic pressure source 70. Hereinafter, a portion where the pressurizing path 60 and the first liquid feeding pipe 51 are connected is referred to as a connecting portion 51a. The air pressure source 70 is a compressor, for example, and is provided in advance in a factory or the like where a machine tool is installed. A switching valve 61 is provided in the pressurizing passage 60. The switching valve 61 has an elastic member and opens and closes by the elastic force and air pressure of the elastic member.

  In the pressurizing passage 60, a check valve 62 is provided between the switching valve 61 and the connecting portion 51a to prevent the cleaning liquid A from flowing back to the switching valve 61 side. In the pressurizing path 60, the distance between the check valve 62 and the connection portion 51 a is longer than the distance between the check valve 62 and the switching valve 61. Here, the distance is not a straight-line distance between two points but a length of a path between two points in the pressurizing path 60, and a curved portion obtains a distance along the curve.

  The first air supply path 71 (air supply path) connects the switching valve 61 and the air pressure source 70. The first electromagnetic valve 71 a (supply valve) is interposed in the first supply passage 71. The first electromagnetic valve 71a opens and closes based on a command from the control unit. The control unit opens the first electromagnetic valve 71 a and supplies air to the switching valve 61. The control unit closes the first electromagnetic valve 71 a and stops the supply of air to the switching valve 61.

  When the first electromagnetic valve 71a is closed and the supply of air to the switching valve 61 is stopped, the switching valve 61 is closed by the elastic force of the elastic member. When the first electromagnetic valve 71a is opened and air is supplied to the switching valve 61, the switching valve 61 opens against the elastic force of the elastic member. When the switching valve 61 is open, the pressurizing path 60 is opened, and air is supplied from the pneumatic pressure source 70 to the first liquid feeding pipe 51. When the switching valve 61 is closed, the pressurizing path 60 is closed, and the supply of air from the air pressure source 70 to the first liquid feeding pipe 51 is stopped.

  The second air supply path 72 connects the air pressure source 70 and the injection valve 55. The second electromagnetic valve 72 a is interposed in the second air supply path 72. The second electromagnetic valve 72a opens and closes based on a command from the control unit. The control unit opens the second electromagnetic valve 72 a and supplies air to the injection valve 55. The control unit closes the second electromagnetic valve 72a and stops the supply of air to the injection valve 55.

  As described above, the injection valve 55 has an elastic member. When the second electromagnetic valve 72a is closed and the supply of air to the injection valve 55 is stopped, the injection valve 55 is closed by the elastic force of the elastic member. When the second electromagnetic valve 72a is opened and air is supplied to the injection valve 55, the injection valve 55 opens against the elastic force of the elastic member.

  When cleaning the tool, the motor 42 rotates based on a command from the control unit. The gear pump 40 is driven to send the cleaning liquid A from the discharge port 47 to the second liquid supply pipe 52. The control unit opens the second electromagnetic valve 72a and opens the injection valve 55. The air pressure source 70 supplies air to the cleaning liquid hose 28 via the injection valve 55. The cleaning liquid A moves along the cleaning liquid hose 28 with air. The cleaning nozzle 30 ejects the cleaning liquid A.

  When the filter 12 is clogged, the value of the pressure gauge 53 becomes smaller than the normal value. The control unit notifies that the value of the pressure gauge 53 is smaller than the normal value (the filter 12 is clogged). The operator operates the operation panel to reversely flow the cleaning liquid A with respect to the filter 12.

  The control unit stops driving the gear pump 40 and closes the second electromagnetic valve 72a. The injection valve 55 is closed. The cleaning liquid A does not flow through the second liquid feeding pipe 52 and the cleaning liquid hose 28. The first liquid feeding pipe 51 is filled with the cleaning liquid A. Further, in the pressurizing passage 60, the cleaning liquid A is filled between the check valve 62 and the connecting portion 51a. The control unit opens the first electromagnetic valve 71a. The switching valve 61 is opened. The air in the air pressure source 70 moves to the first liquid feeding pipe 51 through the pressurizing path 60. The air pushes out the cleaning liquid A in the first liquid feeding pipe 51, the cleaning liquid A between the check valve 62 and the connecting portion 51a in the pressurizing passage 60. The cleaning liquid A flows back through the filter 12 through the first liquid supply pipe 51. Foreign matter such as chips clogged in the filter 12 is detached from the filter 12. The clogging of the filter 12 is eliminated.

  After the clogging of the filter 12 is eliminated, the operator operates the operation panel to end the backflow of the cleaning liquid A with respect to the filter 12. The control unit closes the first electromagnetic valve 71a. The first air supply path 71 is closed.

  When restarting the tool cleaning operation, the control unit opens the second electromagnetic valve 72 a and drives the gear pump 40. The cleaning liquid A moves through the second liquid feeding pipe 52 by driving the gear pump 40. The air pressure source 70 supplies air to the cleaning liquid hose 28 via the injection valve 55. The cleaning liquid A moves along the cleaning liquid hose 28 with air. The cleaning nozzle 30 ejects the cleaning liquid A.

  By driving the gear pump 40, the cleaning liquid A in the tank 11 passes through the filter 12 and the connection portion 51 a and enters the pressurizing path 60 to the check valve 62. The cleaning liquid A fills between the check valve 62 and the connecting portion 51a.

  In the present invention, the first liquid feeding pipe 51 is pressurized by supplying air from the pressurizing passage 60. The cleaning liquid A in the first liquid feeding pipe 51 moves to the filter 12 side by air pressure. The cleaning liquid A flows in the reverse direction through the filter 12, and the clogging of the filter 12 is eliminated. The cleaning liquid filtering device 10 is mainly installed in a factory. The factory already has an air source. Since the pressurizing path 60 is connected to an air source, a large structure is not necessary. Further, it is not necessary to provide a backflow tank for storing the cleaning liquid A, and it is not necessary to secure a large space. Moreover, it is not necessary to newly provide a complicated structure through which the cleaning liquid A flows.

  When the cleaning liquid A is sent from the gear pump 40 to the cleaning nozzle 30, the cleaning liquid A is stored between the check valve 62 and the connecting portion 51 a in the pressurizing passage 60. When the cleaning liquid A is sent from the gear pump 40 to the cleaning nozzle 30, the check valve 62 is closed, so that air accumulates between the check valve 62 and the switching valve 61 in the pressurizing path 60. In the pressurizing path 60, the distance between the check valve 62 and the connecting portion 51a is longer than the distance between the check valve 62 and the switching valve 61, so that the amount of the cleaning liquid A stored in the pressurizing path 60 increases. Therefore, the amount of the cleaning liquid A flowing in the reverse direction through the filter 12 is increased, and the clogging of the filter 12 is reliably eliminated.

  A valve that opens and closes by air pressure is used as the switching valve 61. Compared with the use of a solenoid valve, a valve that opens and closes by air pressure is less likely to fail. In addition, the structure is simple and easy to handle.

  A gear pump 40 is used as a pump for sending the cleaning liquid A to the cleaning nozzle 30. The gear pump 40 has a larger suction force than other pumps (for example, a pump using an impeller). After the cleaning liquid A stored in the first liquid supply pipe 51 and the cleaning liquid A stored between the check valve 62 and the connection part 51a in the pressurizing passage 60 flow back through the filter 12, the gap between the check valve 62 and the connection part 51a Becomes empty. By rotating the gear pump 40, the space between the check valve 62 and the connecting portion 51a that have been emptied can be quickly filled with the cleaning liquid A.

When the value of the pressure gauge 53 becomes smaller than the normal value, the control unit may automatically execute the backflow of the cleaning liquid A with respect to the filter 12 at an appropriate timing.
Further, a pressure gauge may be provided between the check valve 62 and the connecting portion 51a, and the control unit may execute the backflow of the cleaning liquid A with respect to the filter 12 according to the value indicated by the pressure gauge.

A Cleaning liquid 11 Tank 12 Filter 20 Tool body 21 Tool holder 28 Cleaning liquid hose (cleaning liquid passage)
30 Washing nozzle 40 Gear pump (pump)
43 Piping (cleaning fluid passage)
44 Suction port 51 First liquid supply pipe (cleaning liquid passage)
52 Second liquid supply pipe (cleaning liquid passage)
60 Pressurizing path 61 Switching valve 62 Check valve 71 First air supply path (air supply path)
71a First solenoid valve (supply valve)

Claims (3)

A tank for storing the cleaning liquid, a cleaning nozzle for jetting the cleaning liquid to the tool, the cleaning nozzle and the tank are connected, a cleaning liquid passage for supplying the cleaning liquid in the tank to the cleaning nozzle, and a cleaning liquid passage A cleaning liquid filtering device for a machine tool, comprising: a pump for sending the cleaning liquid in the tank to the cleaning nozzle; and a filter disposed on the suction port side of the pump.
A pressure passage connected to the cleaning liquid passage between the filter and the suction port of the pump and pressurizing the inside of the cleaning liquid passage with air ;
A switching valve that is interposed in the pressurizing path and switches supply or stop of supply of air to the cleaning liquid passage;
A check valve that is interposed in the pressurizing passage on the cleaning liquid passage side of the switching valve, and prevents a backflow of air to the switching valve side ,
The cleaning liquid filtration device for a machine tool, wherein the pressurization path between the check valve and the cleaning liquid passage is longer than the pressurization path between the check valve and the switching valve . The switching valve is opened and closed by air pressure,
An air supply path connecting the switching valve and the pneumatic source;
The cleaning liquid filtering device for a machine tool according to claim 1 , further comprising: an air supply valve interposed in the air supply path. The cleaning liquid filtering device for a machine tool according to claim 1 or 2 , wherein the pump is a gear pump.

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