Electrical Discharge Machining Machine

Abstract

The electric discharge machine (100) is an electric discharge machine that generates an electric discharge between a workpiece (W) placed in a machining tank (6) and a machining electrode (9) to machine the workpiece (W) by electric discharge. The electric discharge machine (100) includes the machining tank (6) in which the workpiece (W) is stored, a head (5) disposed above the machining tank (6) and having a machining electrode (9) attached thereto, a movement mechanism (110) that moves the head (5), a power supply device that applies a voltage between the machining electrode (9) and the workpiece (W), a power supply line (8) having one end connected to the machining electrode (9) and electrically connected to the machining electrode (9) and the other end connected to the power supply device, and having a circular cross section, a collection unit (20) through which the power supply line (8) is inserted and that guides the power supply line (8) downward, and a force application unit that applies a force, including a vertically downward force, to the power supply line (8) located between the collection unit (20) and the power supply device.

Description

[Technical Field]

[0001] The present disclosure relates to electrical discharge machines. [Background technology]

[0002] Electric discharge machines apply a voltage between a workpiece and an electrode, and machine the workpiece by generating an electrical discharge between the electrode and the workpiece. For this reason, in electric discharge machines, a power supply line electrically connected to a power supply unit is connected to the machining electrode and the workpiece.

[0003] The power supply line attached to the machining electrode needs to have a length that allows the position of the machining electrode to move to any position within the movement range of the machining electrode during electrical discharge machining of a workpiece, etc. One method for wiring the power supply line attached to the machining electrode is to wire the power supply line inside the structure of the electrical discharge machine. However, when the power supply line is wired inside the structure of the electrical discharge machine, the electrical resistance of the power supply line increases due to the length of the power supply line, which reduces the machining performance of the electrical discharge machine.

[0004] For this reason, it is preferable that the power supply line attached to the machining electrode be wired outside the structure of the electric discharge machine. However, if the power supply line is wired outside the structure of the electric discharge machine, the power supply line may bend inside the machining tank in which the workpiece is placed when the machining electrode is moved, and the power supply line may interfere with the workpiece. For this reason, a configuration is desired for the electric discharge machine in which the power supply line does not interfere with the workpiece when the machining electrode is moved.

[0005] Patent Document 1 describes an electric discharge machine in which a power supply line, one end of which is connected to the machining tank of the electric discharge machine and the other end of which is connected to the electrode, is suspended by an elastic member, thereby reducing slack in the middle part between the two connection points. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-091263 Summary of the Invention [Problem to be solved by the invention]

[0007] However, the electric discharge machine described in Patent Document 1 requires an elastic body between the machining tank and the electrode, which requires space to accommodate the elastic body. This poses a problem of the electric discharge machine being large. Furthermore, if the space required to accommodate the elastic body is large, the amount of overhang of the electric discharge machine increases, which can affect the accuracy of the electric discharge machining.

[0008] The present disclosure has been made in consideration of the above, and aims to provide an electric discharge machine that can suppress interference between a workpiece and a power supply line electrically connected to a machining electrode and a power supply device. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems and achieve the object, the present disclosure provides an electric discharge machine that performs electric discharge machining on a workpiece placed in a machining tank by generating an electric discharge between the workpiece and a machining electrode. The electric discharge machine includes: a machining tank for storing the workpiece; a head disposed above the machining tank and having a machining electrode attached thereto; a moving mechanism for moving the head; a power supply unit for applying a voltage between the machining electrode and the workpiece; a power supply cable having one end connected to the machining electrode and electrically connected to the machining electrode and the other end connected to the power supply unit, the power supply cable having a circular cross section; a collection unit through which the power supply cable is inserted and which guides the power supply cable downward; and a force application unit located between the collection unit and the power supply unit for applying a force, including a vertically downward force, to the power supply cable. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to suppress interference between the workpiece and the power supply line electrically connected to the machining electrode and the power supply device. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a front perspective view showing an outline of an overall configuration of an electric discharge machine according to a first embodiment; [Figure 2] FIG. 1 is a right side view showing an outline of the overall configuration of an electric discharge machine according to a first embodiment; [Figure 3] FIG. 1 is a longitudinal sectional view showing a recovery unit provided in an electric discharge machine according to a first embodiment; [Figure 4] FIG. 10 is a cross-sectional view showing another recovery unit provided in the electric discharge machine according to the first embodiment. [Figure 5] 10 is a cross-sectional view showing a collection section according to a second embodiment. [Figure 6] FIG. 10 is a cross-sectional view showing another collection unit according to the second embodiment. [Figure 7] FIG. 10 is a diagram illustrating an example of a load adjusting mechanism according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] An electric discharge machine according to an embodiment will be described in detail below with reference to the drawings. Note that, although the features of the present disclosure will be described below using a die-sinking electric discharge machine as an example, the features of the present disclosure are not limited to die-sinking electric discharge machines and can be applied to various electric discharge machines that have a power supply line.

[0013] Embodiment 1 Fig. 1 is a front perspective view schematically showing the overall configuration of an electric discharge machine 100 according to a first embodiment. Fig. 2 is a right side view schematically showing the overall configuration of the electric discharge machine 100 according to the first embodiment. Fig. 3 is a vertical cross-sectional view showing a recovery unit 20 provided in the electric discharge machine 100 according to the first embodiment. Note that Fig. 2 shows a state in which the power supply unit 7 is removed.

[0014] 1 to 3, the X-axis direction corresponds to the width direction of the electric discharge machine 100. In FIGS. 1 to 3, the Y-axis direction corresponds to the depth direction of the electric discharge machine 100. In FIGS. 1 to 3, the Z-axis direction corresponds to the height direction of the electric discharge machine 100. The X-axis, Y-axis, and Z-axis are mutually perpendicular axes. The X-axis and Y-axis are two horizontal axes that intersect at right angles. The Z-axis is a vertical axis. In the electric discharge machine 100, the side in the depth direction (Y-axis direction) where a machining tank 6 (described later) is located is referred to as the front side and front, and the side in the depth direction (Y-axis direction) where a column 2 (described later) is located is referred to as the back side and rear. In other words, the front side and front side correspond to the left side in FIG. 2. The back side and rear side correspond to the right side in FIG. 2. The X-axis direction, Y-axis direction, and Z-axis direction correspond to the left-right direction, front-rear direction, and up-down direction, respectively, when the electric discharge machine 100 is viewed from the front.

[0015] Figure 1 From Figure 3 As shown in the figure, the electric discharge machine 100 according to the first embodiment includes a bed 1, a machining tank 6 arranged on the bed 1, a column 2 arranged on the bed 1 behind the machining tank 6, a saddle 3 arranged on the column 2, a ram 4 arranged on the saddle 3, a head 5 arranged in front of the ram 4, a power supply unit 7 arranged to the right of the bed 1 and the column 2, a machining electrode 9 attached to the lower end of the head 5, a power supply line 8 electrically connected to the machining electrode 9 and the power supply unit 7, a recovery unit 20 that recovers the power supply line 8 on the rear surface 6a side of the machining tank 6, and a force application unit 21 that applies a force in the vertical direction to the power supply line 8 on the rear surface 6a side of the machining tank 6. Note that the main components are shown here to explain the features of the electric discharge machine 100, and the components of the electric discharge machine 100 are not limited to those described above.

[0016] The head 5 is located above the machining tank 6. A machining electrode 9 is attached to the lower end of the head 5. That is, during electrical discharge machining of the workpiece W, the machining electrode 9 is supported by a holder 10 at the lower end of the head 5.

[0017] The machining electrode 9 is connected to the power supply line 8 and is electrically connected to the power supply line 8. Therefore, the power supply line 8 is electrically connected to the machining electrode 9 and the power supply device 7. When the machining electrode 9 is used to machine the workpiece W, a high-frequency pulse voltage is applied from the power supply device 7 to the machining electrode 9 and the workpiece W, respectively.

[0018] The saddle 3, the ram 4, and the head 5 constitute a moving mechanism 110 that moves when machining the workpiece W and moves the head 5 to which the machining electrode 9 is attached.

[0019] The moving mechanism 110 moves the machining electrode 9. The moving mechanism 110 has a saddle 3, a ram 4, and a head 5. The moving mechanism 110 moves at least one of the saddle 3, the ram 4, and the head 5, thereby moving the position of the head 5 and thereby moving the position of the machining electrode 9. Therefore, by controlling the movement amount of the moving mechanism 110, i.e., the movement amount of each of the saddle 3, the ram 4, and the head 5, it is possible to control the movement amount of the machining electrode 9 held by the head 5. The movement of the moving mechanism 110 is controlled by a control device (not shown).

[0020] The saddle 3 moves in the width direction of the electric discharge machine 100, i.e., in the X-axis direction in Figures 1 and 2. The ram 4 moves in the width direction of the electric discharge machine 100 and in the depth direction of the electric discharge machine 100, i.e., in the X-axis and Y-axis directions in Figures 1 and 2. The head 5 moves in the width direction of the electric discharge machine 100, in the depth direction of the electric discharge machine 100, and in the height direction of the electric discharge machine 100, i.e., in the X-axis, Y-axis, and Z-axis directions in Figures 1 and 2.

[0021] A surface plate 11 is placed in the machining tank 6. A work chuck 12 that detachably holds a work pallet 13 is placed on the surface plate 11. A work W is attached to the work pallet 13. When machining the work W, machining fluid 14 is supplied to the machining tank 6 from a machining fluid supply device (not shown), and the machining fluid 14 is stored in the machining tank 6.

[0022] The power supply line 8 is electrically connected to the machining electrode 9, and supplies a high-frequency pulse voltage, which is a machining voltage, from the power supply device 7 to the machining electrode 9. The power supply line 8 is wired outside the structure that constitutes the outer shell of the electric discharge machine 100. In this case, the structure that constitutes the outer shell of the electric discharge machine 100 is the machining tank 6, the column 2, the saddle 3, the ram 4, and the head 5.

[0023] The power supply line 8 may be electrically connected to the machining electrode 9 by extending the power supply line 8 into the head 5 and connecting to the machining electrode 9. The power supply line 8 has a circular cross section. The power supply line 8 moves in the width direction, depth direction, and height direction of the electric discharge machine 100, i.e., the X-axis direction, Y-axis direction, and Z-axis direction in FIGS. 1 and 2 , as the movement mechanism 110 moves, i.e., as at least one of the saddle 3, the ram 4, and the head 5 moves.

[0024] The collection unit 20 is arranged on the rear surface 6a side of the machining tank 6, and collects the power supply line 8 extending from the machining electrode 9 on the rear surface 6a side of the machining tank 6. In other words, the collection unit 20 is arranged at a position rearward of the rear surface 5a of the head 5, regardless of where the position of the machining electrode 9 moves within the movement range of the position of the machining electrode 9. The collection unit 20 has, for example, a cylindrical shape. The collection unit 20 is arranged with the axis of the cylindrical shape parallel to, for example, the vertical direction, and the power supply line 8 extending from the machining electrode 9 is inserted through it. An example of the cylindrical shape is a rectangular cylindrical shape. By making the shape of the collection unit 20 rectangular cylindrical, the attachment of the collection unit 20 to the machining tank 6, the column 2, or the saddle 3 becomes easier.

[0025] The power supply line 8 extending from the processing electrode 9 is collected by the collection unit 20 on the back surface 6a side of the processing tank 6, and the extending direction of the power supply line 8 is restricted to the direction toward the collection unit 20. The collection unit 20 collects the power supply line 8 extending from the processing electrode 9 by passing the power supply line 8 through the interior thereof, and guides the power supply line 8 below the collection unit 20 on the back surface 6a side of the processing tank 6.

[0026] Specifically, the recovery unit 20 is arranged on the rear surface 6a side of the processing tank 6, between the column 2 and the processing tank 6, or between the column 2 and the saddle 3 and the processing tank 6. The recovery unit 20 may be attached to the processing tank 6, or may be attached to the column 2 or the saddle 3. That is, the recovery unit 20 is attached to the rear surface 6a of the processing tank 6, the front surface 2a of the column 2, or the front surface 3a of the saddle 3. Therefore, the recovery unit 20 may move in conjunction with the movement of the moving mechanism 110, or may be fixed in position and not move in conjunction with the movement of the moving mechanism 110.

[0027] The collecting portion 20 has insertion openings 20a and 20b at both end surfaces of the cylindrical shape through which the power supply line 8 passes. That is, the power supply line 8 is inserted between the insertion openings 20a and 20b in the collecting portion 20.

[0028] The force application unit 21 applies a force to the power feeder 8 located between the processing electrode 9 and the collection unit 20, pulling the power feeder 8 toward the collection unit 20, in order to suppress deflection of the power feeder 8 between the processing electrode 9 and the collection unit 20 and thereby suppress deflection of the power feeder 8 above the processing tank 6. That is, the force application unit 21 constantly applies a force including a vertically downward force to the power feeder 8 located between the collection unit 20 and the power supply device 7, thereby constantly applying a pulling force to the power feeder 8 located between the processing electrode 9 and the collection unit 20 toward the collection unit 20. Then, the force including the vertically downward force acting on the power feeder 8 located between the processing electrode 9 and the collection unit 20 is converted into a force in a direction other than the vertical direction, starting from the collection unit 20. An example of the direction other than the vertical direction is the XY direction, but is not limited to this.

[0029] By converting a force including a vertically downward force acting on the power feeder 8 located between the processing electrode 9 and the collection unit 20 into a force in a direction other than the vertical direction with the collection unit 20 as the starting point, the power feeder 8 located between the processing electrode 9 and the collection unit 20 can be stretched in a plane direction formed in a direction other than the vertical direction, and it becomes possible to suppress deflection of the power feeder 8 between the processing electrode 9 and the collection unit 20. This makes it possible to suppress deflection of the power feeder 8 located between the processing electrode 9 and the collection unit 20 in the processing tank 6 due to the position of the processing electrode 9 during electrical discharge machining of the workpiece W, etc., and to prevent interference with the workpiece W.

[0030] An example of the force application unit 21 is a heavy object attached to the power supply line 8 located below the collection unit 20 and between the power supply unit 7 and the collection unit 20. By attaching the heavy object to the power supply line 8 located between the power supply unit 7 and the collection unit 20, a force including a vertically downward force can be applied to the power supply line 8 located between the power supply unit 7 and the collection unit 20, and a force can be applied to the power supply line 8 located between the processing electrode 9 and the heavy object, pulling the power supply line 8 toward the heavy object.

[0031] The heavy object is attached to the power supply line 8 located between the power supply device 7 and the collection unit 20 at a position that can obtain the effect of suppressing deflection of the power supply line 8 between the processing electrode 9 and the collection unit 20 as described above, even if the position of the processing electrode 9 fluctuates to any position within the movement range of the position of the processing electrode 9, and can prevent the power supply line 8 located between the processing electrode 9 and the collection unit 20 from interfering with the workpiece W. The attachment position of the heavy object to the power supply line 8 located between the power supply device 7 and the collection unit 20 may be determined in advance by experiment based on various conditions such as the movement range of the processing electrode 9, the length of the power supply line 8, and the weight of the heavy object.

[0032] Next, a modified example of the collection unit 20 will be described. Fig. 4 is a cross-sectional view showing another collection unit 30 provided in the electric discharge machine 100 according to the first embodiment. The other collection unit 30 has, for example, a cylindrical shape. An example of the cylindrical shape is a square cylindrical shape. Note that the other collection unit 30 may also have a cylindrical shape with a closed top end.

[0033] The other collection part 30 has a first insertion opening 30a, which is an insertion opening on the processing electrode 9 side through which the power supply line 8 passes, on a side surface 30c on the processing electrode 9 side of the cylindrical shape. The other collection part 30 also has a second insertion opening 30b, which is an insertion opening on the power supply device 7 side through which the power supply line 8 passes, at a lower end of the cylindrical shape. The power supply line 8 is inserted between the first insertion opening 30a and the second insertion opening 30b. The processing electrode 9 side can be said to be the head 5 side.

[0034] Furthermore, the other collection unit 30 includes a guide portion 30d in an area adjacent to the first insertion opening 30a, which supports the power supply cable 8 inside the other collection unit 30. The guide portion 30d is a support portion that supports and guides downward the power supply cable 8 inserted from the first insertion opening 30a into the other collection unit 30. The guide portion 30d has, for example, a cylindrical shape with a central axis along the width direction of the electric discharge machine 100, i.e., a cylindrical shape with a central axis along the X-axis direction.

[0035] The guide portion 30d is positioned such that its height position on the electric discharge machine 100, i.e., its position in the Z-axis direction, is higher than the height position of the lower end of the first insertion opening 30a and lower than the height position of the upper end of the first insertion opening 30a. Furthermore, the surface of the guide portion 30d preferably has slidability. The slidability of the guide portion 30d can prevent wear on the surface of the power supply cable 8 due to friction between the guide portion 30d and the power supply cable 8.

[0036] In the electric discharge machine 100, even when another collection unit 30 is used instead of the collection unit 20, the same effect as when the collection unit 20 is used can be obtained.

[0037] According to the above-described first embodiment, an electric discharge machining machine that performs electric discharge machining on a workpiece placed in a machining tank by generating an electric discharge between the workpiece and a machining electrode, the electric discharge machining machine including: a machining tank in which the workpiece is stored; a head disposed above the machining tank and having a machining electrode attached thereto; a moving mechanism that moves the head; a power supply unit that applies a voltage between the machining electrode and the workpiece; a power supply line having one end connected to the machining electrode and electrically connected to the machining electrode and the other end connected to the power supply unit and having a circular cross section; a collection unit through which the power supply line is inserted and which guides the power supply line downward; and a force application unit that is located between the collection unit and the power supply unit and which applies a force including a vertical downward force to the power supply line.

[0038] As described above, in the electric discharge machine 100 according to the first embodiment, the power supply line 8 electrically connecting the machining electrode 9 and the power supply unit 7 is wired outside the structure constituting the outer shell of the electric discharge machine 100. In the electric discharge machine 100, the force application unit 21 applies a force to the power supply line 8 located between the machining electrode 9 and the collection unit 20, pulling the power supply line 8 toward the collection unit 20. That is, the force application unit 21 applies a force including a vertically downward force to the power supply line 8 located between the collection unit 20 and the power supply unit 7, thereby applying a force pulling the power supply line 8 located between the machining electrode 9 and the collection unit 20 toward the collection unit 20. The force including the vertically downward force applied to the power supply line 8 located between the machining electrode 9 and the collection unit 20 is converted into a force in a direction other than the vertical direction, with the collection unit 20 as the origin.

[0039] The electric discharge machine 100 configured in this manner can stretch the power feeder 8 located between the processing electrode 9 and the collection unit 20 in a plane direction formed other than the vertical direction between the processing electrode 9 and the collection unit 20, making it possible to suppress deflection of the power feeder 8 between the processing electrode 9 and the collection unit 20. This makes it possible to suppress the power feeder 8 located between the processing electrode 9 and the collection unit 20 from deflecting in the processing tank 6 due to the position of the processing electrode 9 during electric discharge machining of the workpiece W, and from interfering with the workpiece W.

[0040] Furthermore, because the power feeder 8 of the electric discharge machine 100 is wired outside the structure that forms the outer shell of the electric discharge machine 100, the length of the power feeder 8 can be set to the minimum length necessary for the operation of the electric discharge machine 100. This makes it possible for the electric discharge machine 100 to prevent an increase in electrical resistance in the electric wire of the power feeder 8 due to the power feeder 8 being longer than necessary, and to prevent a decrease in machining performance due to the power feeder 8 being longer than necessary.

[0041] Furthermore, the electric discharge machine 100 effectively utilizes the gap between the column 2 or saddle 3 and the machining tank 6 by arranging the recovery section 20 in the gap, and therefore can obtain the above-mentioned effects without increasing the external size of the electric discharge machine 100.

[0042] Therefore, the electric discharge machine 100 according to the first embodiment has the effect of suppressing interference between the workpiece W and the power supply line 8 electrically connected to the machining electrode 9 and the power supply device 7.

[0043] Embodiment 2 In the second embodiment, a modified example of the other collection unit 30 described above, which suppresses wear of the power feeder 8 at the starting point of the collection unit, will be described. The starting point is the portion where the power feeder 8 contacts the collection unit on the processing electrode 9 side. The force, including the vertical downward force, acting on the power feeder 8 located between the processing electrode 9 and the collection unit 20 described above is converted into a force in a direction other than the vertical direction at the starting point. In the above-mentioned FIG. 4, the starting point is the portion where the power feeder 8 contacts the guide portion 30d of the other collection unit 30. other The starting point of the power supply line 8 is a point of contact with the collecting unit 30. The power supply line 8 is in point contact with another collecting unit 30 at the starting point. Note that the starting point in FIG. 3 mentioned above is a point of contact of the power supply line 8 with the collecting unit 20 at the inner periphery of the insertion opening 20a of the collecting unit 20.

[0044] The power feeder 8 inserted into the other collection unit 30 is supported at its starting point by the other collection unit 30. The force application unit 21 applies a force, including a vertically downward force, to the power feeder 8 located between the other collection unit 30 and the power supply device 7, so that a load is continuously applied from the power feeder 8 to the other collection unit 30 at its starting point.

[0045] The power supply line 8 inserted into the other collection unit 30 moves toward the processing electrode 9 or the power supply device 7 as the processing electrode 9 moves. As this operation is continuously performed, the power supply line 8 continuously rubs against the starting point, and even if the starting point has sliding properties, the surface will wear out over the long term.

[0046] 5 is a cross-sectional view showing a collection unit 31 according to the second embodiment. The collection unit 31 according to the second embodiment differs from the other collection units 30 according to the first embodiment in that the collection unit 31 according to the second embodiment includes a roller 30e serving as an interlocking support unit therein instead of the guide unit 30d. The interlocking support unit is a support unit having a function of feeding the power feeder 8 inserted into the collection unit 31 from the first insertion port 30a in the direction of movement of the power feeder 8 in association with the movement of the processing electrode 9. In the following, the interlocking support unit will be described using the roller 30e as an example, but the interlocking support unit is not limited to the roller 30e.

[0047] Similar to the guide 30d described above, the roller 30e is a support that supports and guides downward the power supply cable 8 inserted into the recovery unit 31 through the first insertion opening 30a. The roller 30e rotates, for example, around an unillustrated rotation axis that is aligned with the width direction of the electric discharge machine 100, i.e., an unillustrated rotation axis that is aligned with the X-axis direction. The surface of the roller 30e has sliding properties. The height position of the roller 30e, i.e., its position in the Z-axis direction, is higher than the height position of the lower end of the first insertion opening 30a and lower than the height position of the upper end of the first insertion opening 30a. By positioning the roller 30e at the above height position, it is possible to prevent the power supply cable 8 from coming into contact with and rubbing against the first insertion opening 30a.

[0048] The power feeder 8 is inserted into the recovery unit 31 through the first insertion opening 30a and supported by the recovery unit 31 in line contact with the rollers 30e. In the recovery unit 31, when the power feeder 8 moves toward the processing electrode 9 or the power supply 7 in accordance with the movement of the processing electrode 9, the rollers 30e rotate to feed the power feeder 8 in the moving direction, thereby feeding the power feeder 8 toward the processing electrode 9 or the power supply 7. Therefore, the recovery unit 31 can reduce the force applied from the power feeder 8 to the starting point when the power feeder 8 moves, thereby further suppressing wear of the power feeder 8 due to contact with the recovery unit 31. Furthermore, the recovery unit 31 can more smoothly convert forces, including vertical downward forces, applied to the power feeder 8 located between the processing electrode 9 and the recovery unit 31 into forces in directions other than the vertical direction.

[0049] Therefore, since the recovery section 31 has a sliding roller 30e at its starting point, when the power supply line 8 moves toward the processing electrode 9 or the power supply unit 7 as the processing electrode 9 moves, a rotational force in the rotational direction is generated at the roller 30e, and the force, including the vertical downward force, acting on the power supply line 8 located between the processing electrode 9 and the recovery section 31 can be more smoothly converted into a force in a direction other than the vertical direction.

[0050] 6 is a cross-sectional view showing another collection unit 32 according to embodiment 2. The other collection unit 32 according to embodiment 2 differs from the other collection unit 30 according to embodiment 1 described above in that it includes a sliding guide 30f instead of the guide portion 30d.

[0051] Similar to the above-described guide portion 30d, the sliding guide 30f is a support portion that supports and guides downward the power feeder 8 inserted from the first insertion opening 30a into the other recovery portion 32. The surface of the sliding guide 30f is slidable and is in line contact with the power feeder 8. That is, the sliding guide 30f is in line contact with the power feeder 8 in the longitudinal direction of the power feeder 8 to support the power feeder 8. When the power feeder 8 moves toward the processing electrode 9 or the power supply device 7 in accordance with the movement of the processing electrode 9, the power feeder 8 slides in line contact with the sliding guide 30f.

[0052] In the other collection unit 30 according to the first embodiment, the guide portion 30d is in point contact with the power feeder 8, so that a force is applied locally from the power feeder 8 to the starting point. On the other hand, the sliding guide 30f of the other collection unit 32 is in line contact with the power feeder 8, so that the contact area with the power feeder 8 is wider than that of the guide portion 30d. Therefore, the other collection unit 32 according to the second embodiment can reduce the force applied from the power feeder 8 to each part at the starting point when the power feeder 8 moves, and can further suppress wear of the power feeder 8 due to contact with the other collection unit 32. Furthermore, it can more smoothly convert a force, including a vertically downward force, applied to the power feeder 8 located between the processing electrode 9 and the other collection unit 32 into a force in a direction other than the vertical direction.

[0053] According to the above-described second embodiment, the same effects as those in the first embodiment can be obtained.

[0054] Furthermore, according to the second embodiment, it is possible to obtain an effect of suppressing wear of the power supply wire 8 during electric discharge machining of the workpiece W, etc.

[0055] Embodiment 3 In the above-described first and second embodiments, the load on the starting point of the collection part fluctuates as the processing electrode 9 moves. This causes wear to progress at a specific position of the power feeder 8. Therefore, in the third embodiment, in order to suppress local wear at a specific position of the power feeder 8, the force acting on the starting point of the collection part, including the vertical downward force, is kept constant.

[0056] 7 is a diagram schematically illustrating an example of a load adjustment mechanism 40 according to the third embodiment. The load adjustment mechanism 40 adjusts the load applied to the starting point of the other collection unit 30 to a constant value when the processing electrode 9 moves. This allows the load adjustment mechanism 40 to suppress local wear at a specific position of the power feeder 8 caused by fluctuations in the load applied to the starting point of the other collection unit 30 as the processing electrode 9 moves. That is, the load adjustment mechanism 40 adjusts the load applied to the portion of the guide unit 30d, which is a support unit of the other collection unit 30, with which the power feeder 8 comes into contact, to a constant value, thereby suppressing local wear at a specific position of the power feeder 8 caused by fluctuations in the load applied to the starting point of the other collection unit 30 as the processing electrode 9 moves. When the processing electrode 9 moves, the load acting on the starting point of the other recovery section 30 includes a force including a vertical downward force acting on the starting point due to the action of the force application section 21, and a force acting on the starting point as the processing electrode 9 moves.

[0057] The load adjustment mechanism 40 includes a support portion 41 and a pulley 42 .

[0058] The support member 41 is fixed between the other collection unit 30 and the power supply unit 7. The support member 41 has, for example, a rectangular column shape, and is arranged with the axis of the rectangular column shape parallel to the vertical direction. The support member 41 supports the pulley 42 so that it can move up and down, i.e., in the Z-axis direction. The pulley 42 is biased by a predetermined biasing force in the vertical downward direction by a biasing member (not shown). An example of the biasing member is a spring or a weight. The pulley 42 is a position fixing member that fixes the lowest position of the power supply line 8, which is inserted into the other collection unit 30 through the first insertion port 30a and guided downward by the guide member 30d, outside the other collection unit 30 in conjunction with the movement of the processing electrode 9. That is, the pulley 42 fixes the lowest position of the power supply line 8, which is located between the other collection unit 30 and the power supply unit 7 in the height direction, outside the other collection unit 30 in conjunction with the movement of the processing electrode 9. In the third embodiment, the position fixing portion will be described using the pulley 42 as an example, but the position fixing portion is not limited to the pulley 42.

[0059] 7, pulley 42a indicates pulley 42 located at a predetermined reference height position on support portion 41. Pulley 42b indicates pulley 42 that has moved downward from the reference height position on support portion 41. Pulley 42c indicates pulley 42 that has moved upward from the reference height position on support portion 41.

[0060] When the height position of the connection portion of the power feeder 8 on the processing electrode 9 becomes lower than the height position of the starting point of the other collection unit 30, the pulley 42 moves upward, for example, to the position of pulley 42c. As a result, the load acting on the starting point of the other collection unit 30 is adjusted to the same load as when the pulley 42 is located at the reference height position. Also, when the height position of the connection portion of the power feeder 8 on the processing electrode 9 becomes higher than the height position of the starting point of the other collection unit 30, the pulley 42 moves downward, for example, to the position of pulley 42b. As a result, the load acting on the starting point of the other collection unit 30 is adjusted to the same load as when the pulley 42 is located at the reference height position.

[0061] In this way, the load adjustment mechanism 40 moves up and down continuously based on the vertical relationship between the height position of the connection portion of the power feeder 8 on the processing electrode 9 and the height position of the starting point of the other collection unit 30. As a result, the load adjustment mechanism 40 can absorb fluctuations in the load applied to the starting point of the other collection unit 30 as the processing electrode 9 moves, and adjust the load acting on the starting point of the other collection unit 30 to the same load as when the pulley 42 is located at the reference height position. As a result, the load adjustment mechanism 40 can suppress local wear at a specific position of the power feeder 8 caused by fluctuations in the load applied to the starting point of the other collection unit 30 as the processing electrode 9 moves.

[0062] When the processing electrode 9 moves, the load adjusting mechanism 40 does not necessarily have to adjust the load applied to the starting point of the other collection unit 30 to a constant value, but may adjust the load applied to the starting point of the other collection unit 30 to a load within a predetermined range. This reduces the degree of effect somewhat, but still provides the above-mentioned effect.

[0063] In the above, we have described the case where the load adjustment mechanism 40 is applied to another collection section 30, but the load adjustment mechanism 40 can also be applied to the collection section 20 according to embodiment 1, the collection section 31 according to embodiment 2, and the other collection section 32 according to embodiment 2.

[0064] As described above, the load adjusting mechanism 40 according to the third embodiment can adjust to a constant load the load applied to the portion of the guide portion 30d, which is a support portion of the other collection portion 30, with which the power supply line 8 comes into contact. As a result, the third embodiment has an advantage of being able to suppress local wear at a specific position of the power supply line 8 caused by fluctuations in the load applied to the starting point of the other collection portion 30 as the processing electrode 9 moves.

[0065] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or different embodiments may be combined with each other. It is also possible to omit or modify parts of the configurations as long as they do not deviate from the gist of the invention. [Explanation of symbols]

[0066] 1 bed, 2 column, 2a, 3a front, 3 saddle, 4 ram, 5 head, 5a, 6a back, 6 machining tank, 7 power supply unit, 8 power supply line, 9 machining electrode, 10 holder, 11 surface plate, 12 workpiece chuck, 13 workpiece pallet, 14 machining fluid, 20, 30, 31, 32 recovery section, 20a, 20b insertion port, 21 force application section, 30a first insertion port, 30b second insertion port, 30c side, 30d guide section, 30e roller, 30f sliding guide, 40 load adjustment mechanism, 41 support section, 42, 42a, 42b, 42c pulley, 100 electric discharge machine, 110 moving mechanism, W workpiece.

Claims

1. An electric discharge machine that generates an electric discharge between a workpiece placed in a machining tank and a machining electrode to machine the workpiece, a processing tank in which the workpiece is stored; a head disposed above the machining tank and having the machining electrode attached thereto; a moving mechanism for moving the head; a power supply device that applies a voltage between the processing electrode and the workpiece; a power supply line having one end connected to the processing electrode and electrically connected to the processing electrode, and the other end connected to the power supply device, the power supply line having a circular cross section; a recovery section through which the power feeder cable is inserted and which guides the power feeder cable downward; a force application unit that applies a force including a vertically downward force to the power supply line located between the collection unit and the power supply device; An electric discharge machine comprising:

2. the collecting unit has a support unit that supports the power supply line inserted into the collecting unit; 2. The electric discharge machine according to claim 1,

3. The recovery unit includes: It has a cylindrical shape, a first insertion opening, which is an insertion opening on the processing electrode side and through which the power supply line passes, is provided on a side surface of the cylindrical shape on the processing electrode side; a second insertion opening, which is an insertion opening on the power supply device side through which the power supply line passes, is provided at a lower end of the cylindrical shape; the support portion has an interlocking support portion therein that feeds the power supply line inserted into the recovery portion from the first insertion port in a moving direction of the power supply line in association with movement of the processing electrode; 3. The electric discharge machine according to claim 2, wherein:

4. The recovery unit includes: It has a cylindrical shape, a first insertion opening, which is an insertion opening on the processing electrode side and through which the power supply line passes, is provided on a side surface of the cylindrical shape on the processing electrode side; a second insertion opening, which is an insertion opening on the power supply device side through which the power supply line passes, is provided at a lower end of the cylindrical shape; the support portion has a sliding guide with which the power feeder line slides in line contact in a longitudinal direction of the power feeder line as the processing electrode moves; 3. The electric discharge machine according to claim 2, wherein:

5. a load adjusting mechanism for adjusting a load applied to a portion of the support part with which the power supply line comes into contact as the processing electrode moves; 3. The electric discharge machine according to claim 2, wherein:

6. the force application unit is a heavy object attached to the power supply line located between the recovery unit and the power supply device; 2. The electric discharge machine according to claim 1,

7. The recovery section is disposed on the rear side of the processing tank; 7. The electric discharge machine according to claim 1, wherein:

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