EDM machine processing tank lifting device

Abstract

The machining tank lifting device of the electric discharge machine lifts and lowers the machining tank (4) that stores machining fluid. The machining tank lifting device of the electric discharge machine has a drive source (1) and a rack and pinion (2) for lifting and lowering the machining tank (4) disposed at the rear side of the machining tank (4), and a cylinder (5) disposed at the front side of the machining tank (4) that has the function of preventing the front side of the machining tank (4) from sagging relative to the rear side.

Description

[Technical field]

[0001] The present disclosure relates to a machining tank lifting device for an electric discharge machine. [Background technology]

[0002] In EDM, the workpiece is machined while immersed in the machining fluid. If the machining fluid level drops during machining, it may lead to a fire if the fluid is oil, so from a safety perspective, the fluid level must always be kept at a constant height relative to the workpiece. A surface plate to secure the workpiece is installed inside the machining tank, which stores the machining fluid, and the front and sides of the machining tank are designed to automatically rise and fall in order to allow for easy loading and unloading of the workpiece and access to the workpiece placed on the surface plate.

[0003] In Patent Document 1, from the viewpoint of accessibility to the workpiece, a lifting mechanism for the machining tank, including a motor, rack and pinion, etc., is disposed on the rear side of the machining tank. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 04-038321 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Patent Document 1, the method of arranging the lifting mechanism for the machining tank on the rear side of the machining tank is effective for small machining tanks, but for large machining tanks exceeding approximately 100 kgf, the front side of the machining tank overhangs the rear side of the machining tank to a large extent. As a result, there is a problem that the front side of the machining tank sags and it becomes impossible to maintain the liquid level in the machining tank at a constant height relative to the workpiece.

[0006] The present disclosure has been made in consideration of the above, and aims to provide a machining tank lifting device for an electric discharge machine that can prevent sagging on the front side of the machining tank without compromising access to the workpiece, and can maintain the liquid level in the machining tank at a constant height relative to the workpiece. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems and achieve the object, the machining tank lifting device of the present disclosure lifts and lowers a machining tank that stores machining fluid. The machining tank lifting device of the electric discharge machine has a drive source and a lifting mechanism for lifting and lowering the machining tank disposed at the rear side of the machining tank, and a function for preventing the front side of the machining tank from sagging relative to the rear side of the machining tank at the front side of the machining tank. air Place the cylinder The drive source is controlled so that a second stress greater than the first stress by the air cylinder is generated on the front side of the processing tank when the processing tank is lowered, and the drive source has a first valve that relieves pressure corresponding to the difference between the second stress and the first stress, and is provided with an air circuit connected to the air cylinder. It is characterized by: Effect of the Invention

[0008] The machining tank lifting device of the electric discharge machining machine disclosed herein has the effect of preventing sagging on the front side of the machining tank without compromising access to the workpiece, and of maintaining the liquid level in the machining tank at a constant height relative to the workpiece. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a side view showing a conceptual configuration of a machining tank lifting device for an electric discharge machine according to a first embodiment; [Diagram 2] FIG. 1 is a top view showing a conceptual configuration of a machining tank lifting device for an electric discharge machine according to a first embodiment; [Diagram 3] FIG. 13 is a diagram showing the configuration of an air pressure circuit for driving a cylinder of a machining tank lifting device of an electric discharge machine according to a second embodiment; [Figure 4] 11 is a flowchart showing the operation of the machining tank lifting device of the electric discharge machine according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A machining tank lifting device for an electric discharge machine according to an embodiment will be described in detail below with reference to the drawings.

[0011] Embodiment 1 Fig. 1 is a side view showing a conceptual configuration of a machining tank lifting device for an electric discharge machine according to embodiment 1. Fig. 2 is a top view showing a conceptual configuration of a machining tank lifting device for an electric discharge machine according to embodiment 1. The electric discharge machine is a wire electric discharge machine or a die-sinking electric discharge machine, and the configuration of an electric discharge machining unit including a machining electrode and the like is omitted from the illustration. In Fig. 1, the left side is the front side (front side) of the machining tank, and the right side is the back side of the machining tank.

[0012] As shown in FIG. 1 and FIG. 2, the machining tank lifting device includes a machining tank 4 with a base plate 6 installed on the bottom surface, a rack and pinion 2 as a rotary-linear motion conversion mechanism, a driving source 1, a fixture 3, and a cylinder 5 that performs linear motion. The driving source 1 is, for example, a motor. Electric discharge machining is performed on a workpiece (not shown) on the base plate 6. The rack of the rack and pinion 2 is fixed to the fixture 3. The fixture 3 supports and fixes the machining tank 4. When the motor as the driving source 1 rotates, the pinion of the rack and pinion 2 rotates, and the rack moves up and down as shown by the arrow A with the rotation of the pinion. The movement of the rack moves the machining tank 4 up and down. Machining fluid is supplied to the machining tank 4 from the back side as shown by the arrow B. The cylinder 5 is, for example, an air cylinder. A hydraulic cylinder may be used as the cylinder 5.

[0013] The tip of the rod 5a of the cylinder 5 is disposed on the bottom surface on the front side of the processing tank 4. The cylinder 5 may be disposed in the center of the front side of the processing tank 4, or multiple cylinders 5 may be disposed on the front side of the processing tank 4.

[0014] The drive source 1 and rack and pinion 2, which are the drive mechanism for moving the processing tank 4 up and down, are arranged at the rear side of the processing tank 4. Also, the cylinder 5 is arranged at the front side of the processing tank, forward of the center of gravity of the processing tank. A small cylinder that can realize space saving is used as the cylinder 5. The cylinder 5 does not function to raise the processing tank 4, but functions as a support mechanism for preventing the front side of the processing tank 4 from sagging toward the rear side of the processing tank 4 and for maintaining the horizontality of the processing tank 4. For this reason, a small and inexpensive cylinder can be selected as the cylinder 5.

[0015] 2, the hatched area 7 indicates an access area to the workpiece on the surface plate 6. In order to load and unload the workpiece on the surface plate 6, access is ensured from the front and both sides as shown by the arrows E, making it easy to load and unload the workpiece.

[0016] Thus, according to the first embodiment, the drive source 1 and rack and pinion 2, which are the drive mechanism for moving the machining tank 4 up and down, are disposed at the back side of the machining tank 4, and the cylinder 5, which serves as a support mechanism for keeping the machining tank 4 horizontal, is disposed at the front side of the machining tank 4, so that the machining fluid level in the machining tank 4 can always be kept at a constant height relative to the workpiece. Also, because a small air cylinder can be used, space can be secured in front and on the sides of the machining tank 4, improving access to the workpiece.

[0017] Embodiment 2 3 is a diagram showing the configuration of an air pressure circuit that drives cylinder 5 of a machining tank lifting device of an electric discharge machine according to a second embodiment. The air pressure circuit includes relief valve 12, which is a first valve connected to an air supply source (not shown), and pilot check valve 13. Relief valve 12 is connected to the air supply source by air passage 15, and relief valve 12 is connected to pilot check valve 13 by air passage 16. A pilot line of pilot check valve 13 is connected to the air supply source via air passage 17. Pilot check valve 13 is connected to the bottom side of cylinder 5 by air passage 18.

[0018] The pilot check valve 13 applies air pressure, which normally acts in the direction of path α, to the bottom side of the cylinder 5, but when air pressure is applied to path γ, it causes air from the bottom side of the cylinder 5 to flow back in the direction of path β. The relief valve 12 has the function of maintaining the air pressure in the air path 16 within a certain relief pressure, and relieves air that exceeds the certain relief pressure.

[0019] The driving source 1 is connected to a control device 8 that controls the driving of the driving source 1. The control device 8 is connected to an operation screen 9.

[0020] In the first embodiment, it is possible to always maintain the machining fluid level at a constant height relative to the workpiece when the machining tank 4 is rising or stopped, but if the air supply is stopped when the machining tank 4 is lowered, there is a possibility that the front side of the machining tank 4 will sag relative to the back side of the machining tank 4. Therefore, in the second embodiment, the machining tank 4 is configured to be able to be lowered while applying the same level of air pressure as when the machining tank 4 is rising.

[0021] When the processing tank 4 rises, air pressure is applied to the path α, so that the front side of the processing tank 4 does not sag relative to the back side by being held by the rod 5a of the cylinder 5. Specifically, when the processing tank 4 rises or is held at a constant height, as shown in FIG. 1, stress C from the cylinder 5 and stress D in the opposite direction to stress C caused by the operation of the driving source 1 are generated on the front side of the processing tank 4. Stress C corresponds to the first stress, and stress D corresponds to the second stress. When the processing tank 4 rises or is held at a constant height, stress D is greater than stress C, so air pressure is not applied to the cylinder 5 in the direction of path β, air is not relieved from the relief valve 12, and the cylinder 5 is held in an extended state. If stress D is extremely large compared to stress C, a load is applied to the driving source 1, so the stress difference is set to a level that does not apply a load to the driving source 1.

[0022] On the other hand, when the processing tank 4 is lowered, air pressure acting in the direction of path α is applied to the bottom side of the cylinder 5 from the air supply source via the air path 15, with the same magnitude as the air pressure when the processing tank 4 is raised. As a result, stresses C and D from the cylinder 5 act on the processing tank 4, just as when the processing tank 4 is raised. However, the force from the driving source 1 and the air pressure of the air supply source are set so that the stress D when the processing tank 4 is lowered is greater than the stress C from the cylinder 5. At this time, the force of the driving source 1 to hold the current position is stronger than the stress D, so the height of the front side and the height of the back side of the processing tank 4 are the same.

[0023] Since stress D is greater than stress C, air pressure is applied in the direction of path β via cylinder 5. Since air pressure from path γ acts on the pilot line of pilot check valve 13, air is discharged from pilot check valve 13 to path β. Here, the relief pressure of relief valve 12 is set to an air pressure corresponding to stress C. Therefore, air is discharged from relief valve 12 by an amount equal to the difference between stress D generated by drive source 1 and stress C from cylinder 5. Therefore, even when machining tank 4 is lowered, it is possible to lower machining tank 4 while air pressure is being applied.

[0024] Thus, according to embodiment 2, when the machining tank 4 is lowered, the operation of the drive source 1 generates a stress C in the machining tank 4 that is greater than the stress D from the cylinder 5, and the air pressure corresponding to the difference between the generated stress C and stress D is relieved. Therefore, even when the machining tank is lowered, the front side of the machining tank 4 can be prevented from sagging relative to the back side of the machining tank 4, and the machining fluid level in the machining tank 4 can always be maintained at a constant height relative to the workpiece.

[0025] Embodiment 3 4 is a flow chart showing the operation of the machining tank lifting device of the electric discharge machine according to the third embodiment. The configuration of the machining tank lifting device of the electric discharge machine according to the third embodiment is the same as that shown in FIG. 3, and a duplicated description will be omitted. When the rod 5a of the cylinder 5 is stored in the cylinder body, the movement of the rod 5a becomes poor due to aging, dirt, and dust adhesion. As a result, the operation of the cylinder 5 becomes unstable, the operation of the machining tank 4 is not completed normally, the machine may stop, or a load may be applied to the cylinder 5, causing damage to the parts of the cylinder 5.

[0026] Therefore, in the third embodiment, in order to prevent or predict damage to parts of the cylinder 5, the stress applied from the cylinder 5 to the driving source 1 is detected by measuring the load data applied to the driving source 1. The measured load data applied to the driving source 1 is fed back to the control device 8. When the driving source 1 is a motor, the current value generated in the motor is used as the load data. A first threshold value and a second threshold value are set in the control device 8. The second threshold value is greater than the first threshold value. When the load data exceeds the first threshold value, the control device 8 displays a warning on the operation screen 9 to prompt maintenance. In this state, the machine is not stopped and the operation is continued. Furthermore, when the load data exceeds the second threshold value, the control device 8 stops the electric discharge machine and displays a message to that effect on the operation screen 9. Hereinafter, the operation will be described with reference to FIG. 4.

[0027] First, an operation instruction is output from the control device 8 to the driving source 1 (step S100). As a result, the driving source 1 executes an operation (step S110), and the processing tank 4 rises and falls (step S120). In addition, the cylinder 5 executes an extension and retraction operation (step S130). When a load is applied to the driving source 1 (step S140), the load data is fed back to the control device 8 (step S150). The control device 8 determines whether the load data is greater than a first threshold value (step S160). If the load data is equal to or less than the first threshold value (step S160: No), the procedure proceeds to step S100. If the load data is greater than the first threshold value (step S160: Yes), the control device 8 displays a warning to prompt maintenance on the operation screen 9 (step S170).

[0028] Next, an operation instruction is output from the control device 8 to the driving source 1 (step S180). As a result, the driving source 1 executes an operation (step S190), and the machining tank 4 rises and falls (step S200). Also, the cylinder 5 executes an extension and retraction operation (step S210). When a load is applied to the driving source 1 (step S220), the load data is fed back to the control device 8 (step S230). The control device 8 determines whether the load data is greater than a second threshold value (step S240). If the load data is equal to or less than the second threshold value (step S240: No), the procedure proceeds to step S180. If the load data is greater than the second threshold value (step S240: Yes), the control device 8 stops the electric discharge machine (step S250) and displays on the operation screen 9 that the machine has stopped (step S260).

[0029] In this way, in embodiment 3, when the load on drive source 1 exceeds a first threshold value, a warning is displayed to prompt maintenance, and when the load on drive source 1 exceeds a second threshold value, the electric discharge machining device is stopped. This makes it possible to prevent damage to components of cylinder 5 and malfunctions of the machining tank lifting device caused by damage to components of cylinder 5.

[0030] The configurations shown in the above embodiments are examples of the contents of the present disclosure, and may be combined with other known technologies, or the embodiments may be combined with each other. Also, parts of the configurations may be omitted or modified without departing from the gist of the present disclosure. [Explanation of symbols]

[0031] 1 Drive source, 2 Rack and pinion, 3 Mounting fixture, 4 Processing tank, 5 Cylinder, 5a Rod, 6 Plate, 7 Area, 8 Control device, 9 Operation screen, 12 Relief valve, 13 Pilot check valve, 15, 16, 17, 18 Air passages.

Claims

1. In a machining tank lifting device for an electrical discharge machining machine that lifts and lowers a machining tank containing machining fluid, A drive source and a lifting mechanism for raising and lowering the processing tank are arranged at the rear of the processing tank. An air cylinder is placed on the front side of the processing tank, which has the function of preventing the front side from sagging relative to the back side of the processing tank. The drive source is controlled so that when the processing tank is lowered, a second stress in the opposite direction, greater than the first stress caused by the air cylinder, is generated on the front side of the processing tank. It has a first valve that relieves the pressure corresponding to the difference between the second stress and the first stress, and an air circuit connected to the air cylinder. A lifting device for the machining tank of an electrical discharge machining machine, characterized by the following features.

2. The control device acquires the load applied to the drive source and displays a warning when the load exceeds a first threshold. The machining tank lifting device for an electrical discharge machining machine as described in claim 1.

3. The control device stops the electrical discharge machining machine and displays that the electrical discharge machining machine has been stopped when the load exceeds a second threshold, which is greater than the first threshold. The machining tank lifting device for an electrical discharge machining machine as described in feature 2.

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