Machine tool

Abstract

To reduce electric power consumption of a pump for coolant supply.SOLUTION: A coolant supply device 4 of a machine tool 1 comprises a pump 16 for pumping a coolant CL, a valve 20 for controlling supply of the coolant CL, and a discharge part 22 for discharging the coolant CL. The valve 20 controls the supply of the coolant CL to the discharge part 22 so that the discharge part 22 can intermittently discharge the coolant CL.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a machine tool such as a machining center. [Background technology]

[0002] Patent Document 1 discloses a cutting fluid supply device that supplies cutting fluid (coolant) to a machine tool. The cutting fluid supply device includes a storage tank that stores cutting fluid, an in-machine cleaning pump that pumps the cutting fluid to the machine tool, an in-machine cleaning nozzle that discharges cutting fluid, a supply flow path (third cutting fluid flow path) that connects the in-machine cleaning pump and the in-machine cleaning nozzle, and a valve (third on-off valve) provided in the supply flow path (see paragraphs 0022, 0028, 0038 and Figure 1 of the document).

[0003] The cutting fluid supply device drives an internal cleaning pump to pressure-feed cutting fluid stored in a storage tank through a supply flow path to an internal cleaning nozzle, which discharges the cutting fluid from a discharge port at its tip onto the workpiece and the surrounding bed (see paragraphs 0047 and 0049 of the same document).

[0004] In some cases, the internal cleaning nozzles are provided at multiple locations inside the machine tool (see paragraph 0024 and FIG. 1 of Patent Document 2). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2019-76999 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-123764 Summary of the Invention [Problem to be solved by the invention]

[0006] In conventional cutting fluid supply devices, the internal cleaning pump must be continuously driven to continuously discharge cutting fluid from the storage tank through the internal cleaning nozzle. When machining a large number of workpieces, the internal cleaning pump's operating time increases in proportion to the number of workpieces, resulting in increased power consumption.

[0007] The present invention has been made in view of the above circumstances, and has as its technical object to reduce the amount of power consumed by a pump for supplying coolant. [Means for solving the problem]

[0008] The present invention is intended to solve the above-mentioned problems, and provides a machine tool equipped with a coolant supply device that supplies coolant into the machine, the coolant supply device including a pump that pressurizes the coolant, a valve that controls the amount of coolant supplied, and a discharge unit that discharges the coolant, and the valve controls the supply of coolant to the discharge unit so that the discharge unit discharges the coolant intermittently.

[0009] With this configuration, by intermittently supplying coolant from the discharge port of the coolant supply device to the inside of the machine tool (inside the machine), the total flow rate of coolant supplied to the machine tool during machining can be reduced compared to when coolant is supplied continuously, which makes it possible to reduce the power consumption of the pump for supplying coolant.

[0010] In the machine tool having the above configuration, the valve may include a first valve and a second valve, the discharge portion may include a first discharge portion corresponding to the first valve and a second discharge portion corresponding to the second valve, and the supply of the coolant to the first discharge portion by the first valve and the supply of the coolant to the second discharge portion by the second valve may be alternately performed.

[0011] In the machine tool having the above configuration, the valve may include a first valve and a second valve, the discharge portion may include a first discharge portion corresponding to the first valve and a second discharge portion corresponding to the second valve, and the first discharge portion and the second discharge portion may be arranged so that the discharge directions of the coolant intersect. [Effects of the Invention]

[0012] According to the present invention, it is possible to reduce the amount of power consumed by the pump for supplying coolant. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram of a machine tool. [Figure 2] FIG. 2 is a side view illustrating an example of a discharge portion of a coolant supply device. [Figure 3] FIG. 4 is a side view showing the direction in which coolant is discharged from a discharge portion of the coolant supply device. [Figure 4] FIG. 2 is a plan view illustrating an example of a discharge portion of a coolant supply device. [Figure 5] FIG. 3 is a plan view showing the direction in which coolant is discharged from a discharge portion of the coolant supply device. [Figure 6] 10 is a flowchart showing a coolant supply method. [Figure 7] 10 is a graph showing the relationship between the flow rate of the coolant and time for the first valve of the coolant supply device. [Figure 8] 10 is a graph showing the relationship between the flow rate of the coolant and time for the second valve of the coolant supply device. [Figure 9] 10 is a graph showing the relationship between the flow rate of the coolant and time for a first valve of a conventional coolant supply device. [Figure 10] 10 is a graph showing the relationship between the flow rate of the coolant and time in the second valve of the conventional coolant supply device. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the machine tool according to the present invention will now be described with reference to the accompanying drawings.

[0015] As shown in Fig. 1, machine tool 1 includes a bed 2, a jig 3 that supports a workpiece W, a coolant supply device 4, a cover 5, and a control device 6. Machine tool 1 can perform various types of machining on workpiece W held by jig 3 by moving tools 7 arranged inside the machine relative to bed 2.

[0016] The bed 2 has a support surface 8 that supports the jig 3, and a discharge flow path 9 that discharges chips generated by machining the workpiece W. The support surface 8 is provided on the upper part of the bed 2. The discharge flow path 9 has a first opening 10 formed on the upper part of the bed 2, an inclined surface 11 formed inside the bed 2, and a second opening 12 formed on the side of the bed 2. Chips that fall from the workpiece W during machining are received in the discharge flow path 9 from the first opening 10, pass through the inclined surface 11, and are discharged outside the bed 2 from the second opening 12.

[0017] 1 and 2, the jig 3 includes a support member 13 that supports the bottom surface of the workpiece W, and a pressing member 14 that presses down on the workpiece W. The support member 13 has a support surface 13a that contacts the workpiece W. The support surface 13a is configured as a reference surface for positioning the workpiece W. The pressing member 14 contacts the top surface of the workpiece W so as to sandwich the workpiece W together with the support member 13.

[0018] The coolant supply device 4 includes a storage tank 15 for storing the coolant CL, a pump 16 for pumping the coolant CL stored in the storage tank 15, supply flow paths 17-19 for the coolant CL, and discharge portions 22-24 for discharging the coolant CL into the machine.

[0019] The pump 16 is configured by, for example, a centrifugal volute pump, but the type of the pump 16 is not limited to this embodiment.

[0020] The supply passages 17 to 19 include a main supply passage 17 connected to the pump 16, and a first supply passage 18 and a second supply passage 19 branching off from the main supply passage 17.

[0021] The first supply flow path 18 has a first valve (flow rate control valve) 20 in its middle. The second supply flow path 19 has a second valve (flow rate control valve) 21 in its middle. Each of the valves 20, 21 is configured, for example, by an electromagnetic control valve, and controls the supply of coolant CL to each of the discharge portions 22-24 so that each of the discharge portions 22-24 intermittently discharges the coolant CL.

[0022] The first supply flow path 18 has branch flow paths 18a to 18d that branch into a plurality of paths, and the second supply flow path 19 has branch flow paths 19a and 19b that branch into a plurality of paths.

[0023] Although not shown, the coolant supply device 4 has a separate tool supply flow path that supplies the coolant CL in the storage tank 15 to the tool 7. The tool supply flow path is connected to a pump 16.

[0024] 1, the discharge units 22 to 24 include a jig discharge unit 22 that supplies coolant CL to the jig 3, a bed discharge unit 23 that supplies coolant CL to the bed 2, and a wall discharge unit 24 that supplies coolant CL to a wall unit of the cover 5 that constitutes the housing of the machine tool 1. Each of the discharge units 22 to 24 has one or more nozzles that can spray the coolant CL.

[0025] The jig discharge section 22 is a first discharge section that is connected to the first supply flow path 18 and receives the supply of coolant CL via a first valve 20. The bed discharge section 23 and the wall discharge section 24 are second discharge sections that are connected to the second supply flow path 19 and receive the supply of coolant CL via a second valve 21.

[0026] 1 to 4, the jig discharge section 22 includes a first jig discharge section 22a, a second jig discharge section 22b, a third jig discharge section 22c, and a fourth jig discharge section 22d. As shown in Fig. 4, each of the jig discharge sections 22a to 22d includes two nozzles arranged side by side at a predetermined interval. Each of the jig discharge sections 22a to 22d is connected to a corresponding one of the branch flow paths 18a to 18d of the first supply flow path 18. The number of nozzles in each of the jig discharge sections 22a to 22d is not limited to that in this embodiment.

[0027] 1 to 4, the first jig discharge portion 22a and the second jig discharge portion 22b are spaced apart at a fixed interval. The first jig discharge portion 22a and the second jig discharge portion 22b are disposed opposite each other so that the workpiece W and the jig 3 are located therebetween. With this configuration, as shown in Fig. 3, the first jig discharge portion 22a and the second jig discharge portion 22b are disposed so that the discharge directions D1 and D2 of the coolant CL intersect in a side view.

[0028] 4, the third jig discharge portion 22c and the fourth jig discharge portion 22d are spaced apart at a fixed interval. The third jig discharge portion 22c and the fourth jig discharge portion 22d are arranged opposite each other so that the workpiece W and the jig 3 are located therebetween. As a result, the third jig discharge portion 22c and the fourth jig discharge portion 22d are arranged so that the discharge directions of the coolant CL intersect in a side view (not shown).

[0029] 4 and 5, the first jig discharge portion 22a and the third jig discharge portion 22c are arranged so that the discharge directions D1 and D3 of the coolant CL intersect in a plan view. In this embodiment, the angle between the discharge direction D1 of the coolant CL at the first jig discharge portion 22a and the discharge direction D3 of the coolant CL at the third jig discharge portion 22c is 90°, but this is not limited to this embodiment. Similarly, although not shown, the first jig discharge portion 22a and the fourth jig discharge portion 22d are arranged so that the discharge directions of the coolant CL intersect (are perpendicular) in a plan view. The same applies to the arrangement of the second jig discharge portion 22b and the third jig discharge portion 22c, and the second jig discharge portion 22b and the fourth jig discharge portion 22d.

[0030] 1, the bed discharge section 23 is arranged in the middle of the discharge flow path 9 so as to supply coolant CL to the discharge flow path 9 of the bed 2. The bed discharge section 23 is connected to one branch flow path 19a of the second supply flow path 19. The wall discharge section 24 is arranged so as to face the wall of the cover 5. The wall discharge section 24 is connected to the other branch flow path 19b of the second supply flow path 19. In the present embodiment, one bed discharge section and one wall discharge section 24 are illustrated as examples, but the present invention is not limited to this, and two or more of each of the discharge sections 23, 24 may be arranged inside the machine.

[0031] The control device 6 executes drive control of the pump 16 and opening / closing control of the valves 20 and 21. The control device 6 alternately supplies coolant CL to a jig discharge portion 22 serving as a first discharge portion through the first valve 20, and to a bed discharge portion 23 and a wall discharge portion 24 serving as second discharge portions through the second valve 21. The control device 6 has a built-in timer, and switches between opening and closing control of the first valve 20 and the second valve 21 based on a predetermined time set by the timer.

[0032] A method for machining a workpiece W using the machine tool 1 configured as described above will now be described. In this method, first, the workpiece W is placed inside the machine tool 1. Once the workpiece W is supported by a jig 3 on the bed 2, a predetermined machining process is performed on the workpiece W using a tool 7. The coolant supply device 4 drives the pump 16 to pressure-feed the coolant CL to each of the discharge ports 22-24 through the supply flow paths 17-19. Each of the discharge ports 22-24 discharges the coolant CL toward a predetermined position inside the machine.

[0033] 6, a method for supplying coolant CL by coolant supply device 4 will be described in detail. When machining by machine tool 1 starts, control device 6 drives pump 16 and controls the opening and closing of first valve 20 and second valve 21.

[0034] The control device 6 starts a built-in timer and alternately opens and closes the first valve 20 and the second valve 21 based on the time (n seconds) set on the timer, thereby intermittently supplying the coolant CL to each of the discharge ports 22 to 24.

[0035] 6, the control device 6 starts (ON) the timer, opens (ON) the first valve 20, and closes (OFF) the second valve 21. As a result, the jig discharge portion 22 serving as a first discharge portion connected to the first valve 20 discharges the coolant CL toward the jig 3. The coolant CL discharged from the bed discharge portion 23 allows chips generated during machining to flow into the discharge flow path 9 of the bed 2 without adhering to the jig 3. On the other hand, the bed discharge portion 23 and the wall discharge portion 24 serving as second discharge portions connected to the second valve 21 in the closed state do not discharge the coolant CL.

[0036] The control device 6 maintains the above state until the time (n seconds) set by the timer has elapsed. When the time set by the timer has elapsed (Yes in step S2), the control device 6 executes the valve switching step (step S3).

[0037] Specifically, the first valve 20, which is in the open state (ON), is switched to the closed state (OFF), and the second valve 21, which is in the closed state (OFF), is switched to the open state (ON). Furthermore, the control device 6 resets the timer setting time (n seconds). After this valve switching process, if the machining is not completed (No in step S4), the control device 6 maintains the above-described supply state of the coolant CL until the timer setting time (n seconds) has elapsed.

[0038] When the timer setting time has elapsed (Yes in step S2), the control device 6 again executes the valve switching step (step S3). That is, the control device 6 switches the first valve 20, which is in the closed state (OFF), to the open state (ON), and switches the second valve 21, which is in the open state (ON), to the closed state (OFF). The control device 6 repeatedly executes the above control (steps S2 and S3) until machining by the machine tool 1 is completed.

[0039] When the processing of the workpiece W is completed, the control device 6 stops the pump 16 and the timer, switches the first valve 20 and the second valve 21 to the closed state (OFF) (step S5), and terminates the supply of the coolant CL.

[0040] Fig. 7 is a graph showing the manner in which the flow rate of the coolant CL is controlled by the first valve 20. Fig. 8 is a graph showing the manner in which the flow rate of the coolant CL is controlled by the second valve 21. In Figs. 7 and 8, the horizontal axis represents time T (s), and the vertical axis represents the flow rate Q of the coolant CL per unit time (1 second) (the flow rate Q of the coolant CL discharged from the first discharge portion or the second discharge portion: L / s).

[0041] 7 and 8, the first valve 20 and the second valve 21 control the flow rate Q of the coolant CL so that the jig discharge portion 22 as a first discharge portion, and the bed discharge portion 23 and wall discharge portion 24 as second discharge portions intermittently discharge a constant amount of coolant CL. Furthermore, the first valve 20 and the second valve 21 control the flow rate Q so that the corresponding first discharge portion and second discharge portion alternately discharge the coolant CL.

[0042] 7, the first valve 20 is open from the start of machining TS to time T1 and supplies a constant flow rate L1 of coolant CL. Thereafter, the first valve 20 is closed from time T1 to time T2 and does not supply the coolant CL. Thereafter, the first valve 20 is open from time T2 to time T3 and supplies the coolant CL, and is closed from time T3 to time T4 and does not supply the coolant CL. The first valve 20 then repeats this intermittent supply of coolant CL from time T5 until the end of machining TE.

[0043] As described above, the second valve 21 is in a closed state when the first valve 20 is supplying the coolant CL, and is in an open state when the first valve 20 is not supplying the coolant CL.

[0044] 8, the second valve 21 is closed from the start of machining TS to time T1 and does not supply coolant CL. Thereafter, the second valve 21 is open from time T1 to time T2 and supplies coolant CL at a constant flow rate L1, and is closed from time T2 to time T3 and does not supply coolant CL. The second valve 21 then repeats this intermittent supply of coolant CL from time T4 until the end of machining TE.

[0045] 9 and 10 are graphs showing a conventional method of supplying coolant CL, for comparison with the manner of flow rate control of coolant CL shown in Figures 7 and 8. Figure 9 shows a case where coolant CL is continuously supplied at a constant flow rate L1 from the start of machining TS to the end of machining TE without flow rate control by the first valve 20. Similarly, Figure 10 shows a case where coolant CL is continuously supplied at a constant flow rate L1 without flow rate control by the second valve 21.

[0046] 7 with FIG. 9 and with FIG. 8 with FIG. 10, the method of supplying coolant CL by machine tool 1 of this embodiment can reduce the total flow rate (Q×T) of coolant CL supplied into the machine from the start time TS of machining to the end time TE of machining, compared to conventional supply methods. The power consumption of pump 16 varies depending on the amount of coolant CL supplied by pump 16, i.e., the total flow rate of coolant CL discharged from each of discharge ports 22-24. In this embodiment, by reducing the total flow rate of coolant CL as described above, the power consumption of pump 16 can be reduced compared to conventional methods. This makes it possible to minimize the manufacturing costs of workpieces W machined by machine tool 1.

[0047] Furthermore, in the method of supplying coolant CL by the machine tool 1 of this embodiment, the opening and closing operation of the first valve 20 and the opening and closing operation of the second valve 21 are alternately performed, thereby preventing the occurrence of water hammer in the coolant supply device 4. This embodiment is not limited to the above-described embodiment, and by taking additional measures to prevent water hammer, it is possible to perform intermittent opening and closing control of the valves 20, 21 so that, for example, the first valve 20 and the second valve 21 are closed simultaneously.

[0048] Furthermore, according to this embodiment, by intermittently supplying the coolant CL from each of the discharge portions 22 to 24, it is possible to generate a flow of coolant CL that varies in speed when it is discharged (sprayed) from the discharge portions 22 to 24. Such a flow of coolant CL that varies in speed can effectively wash away chips that are generated from the workpiece W during machining.

[0049] In addition, by intersecting the discharge directions D1 to D3 of the coolant CL from the multiple jig discharge portions 22 (22a to 22d), the coolant CL can be supplied to the jig 3 from multiple different directions. In this way, by generating flows of the coolant CL with varying speeds from multiple different directions, the cleaning effect on the jig 3 can be improved.

[0050] In addition to the above, the coolant supply device 4 can supply the coolant CL to the tool 7 during machining through the tool supply flow path. The supply of the coolant CL to the tool 7 can be carried out continuously.

[0051] The present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. The present invention can be modified in various ways without departing from the spirit of the present invention.

[0052] In the above embodiment, an example was shown in which the coolant CL was intermittently supplied into the machine using two valves, the first valve 20 and the second valve 21, but the present invention is not limited to this configuration. For example, one valve may be provided in the supply flow path of the coolant CL, and the coolant CL supplied from this valve may be intermittently discharged into the machine using one or more discharge portions.

[0053] It is also possible to use three or more valves to intermittently supply coolant CL. For example, the first valve 20 may control the amount of coolant CL discharged from the jig discharge portion 22, the second valve 21 may control the amount of coolant CL discharged from the bed discharge portion 23, and the third valve may control the amount of coolant CL discharged from the wall discharge portion 24. In this case, the opening and closing of each valve may be controlled so that when two valves are open, the remaining valve is closed. In other words, when coolant is supplied using three or more valves, each valve can be controlled so that at least one valve is closed and the remaining valves are open.

[0054] In the above embodiment, the first jig discharge portion 22a and the second jig discharge portion 22b are arranged so that the discharge directions D1, D2 of the coolant CL intersect in a side view, but the present invention is not limited to this configuration. For example, two or more bed discharge portions 23 may be provided in the machine tool 1, and two of the bed discharge portions 23 may be arranged so that the discharge directions of the coolant CL intersect. Furthermore, the jig discharge portion 22 and the bed discharge portion 23 may be arranged so that the discharge directions of the coolant CL intersect, or the jig discharge portion 22 and the wall discharge portion 24, and the bed discharge portion 23 and the wall discharge portion 24 may be arranged so that the discharge directions of the coolant CL intersect.

[0055] In the above embodiment, the jig discharge portions 22a to 24 of the jig discharge portion 22 are arranged so that the directions of discharge of the coolant CL intersect in a plan view, but the present invention is not limited to this configuration. The jig discharge portion 22 and the bed discharge portion 23, the jig discharge portion 22 and the wall discharge portion 24, and the bed discharge portion 23 and the wall discharge portion 24 can also be arranged in a similar manner.

[0056] In the above embodiment, the wall discharge unit 24 that sprays coolant CL onto the wall of the cover 5 of the machine tool 1 is illustrated, but the present invention is not limited to this configuration. For example, the wall discharge unit 24 may discharge coolant CL onto the shutter of a tool magazine that stores various types of tools inside the machine.

[0057] In the above embodiment, the open time and closed time of each valve 20, 21 are set to be equal, but the present invention is not limited to this configuration. For example, the open time and closed time of each valve 20, 21 may be different. The open time of the first valve 20 may be different from the open time of the second valve 21. The closed time of the first valve 20 may be different from the closed time of the second valve 21.

[0058] The control device 6 can set appropriate times for opening and closing the valves 20 and 21 depending on the type of tool 7 used for machining. [Explanation of symbols]

[0059] 1 Machine tools 4 Coolant supply device 16 Pump 20 First Valve 21 Second valve 22 Jig outlet 22a First discharge part 22b Second discharge part 23 Bed outlet 24 Wall outlet CL Coolant D1 Coolant discharge direction at first jig discharge port D2 Coolant discharge direction at the second jig discharge port D3 Coolant discharge direction at the third jig discharge port

Claims

1. In a machine tool equipped with a coolant supply device that supplies coolant into the machine, the coolant supply device includes a pump that pressure-feeds the coolant, a valve that controls the amount of the coolant supplied, and a discharge unit that discharges the coolant; The machine tool, wherein the valve controls the supply of the coolant to the discharge portion so that the discharge portion discharges the coolant intermittently.

2. The valve includes a first valve and a second valve, the discharge portion includes a first discharge portion corresponding to the first valve and a second discharge portion corresponding to the second valve; The machine tool according to claim 1 , wherein the supply of the coolant to the first discharge port by the first valve and the supply of the coolant to the second discharge port by the second valve are alternately performed.

3. The valve includes a first valve and a second valve, the discharge portion includes a first discharge portion corresponding to the first valve and a second discharge portion corresponding to the second valve; The machine tool according to claim 1 or 2, wherein the first discharge portion and the second discharge portion are arranged so that the directions in which the coolant is discharged intersect.

Images