JP4522733B2 - Electrical discharge switching circuit switching device and electrical discharge machining power circuit switching device - Google Patents

Description

  The present invention relates to an improvement in a switching device for switching or using a plurality of types of power supply circuits included in a switching device for an electrical circuit for electrical discharge machining and a power supply device for electrical discharge machining.

  Electric discharge machining power supply for supplying electrical energy for machining between the machining electrode and the workpiece is highly advanced, and a tool electrode complementary to the machining shape is used opposite to the workpiece as the tool electrode. In the EDM machine and the wire EDM machine that uses a linear electrode as the tool electrode and is used for processing in a sawtooth shape, the power supply circuit is not significantly different in length. Even in a wire electric discharge machine, each power supply device has its purpose of machining or form of machining, required machining speed, finished surface roughness, dimensional accuracy and their level, etc., or further used electrodes and workpieces. Furthermore, it is equipped with a plurality of types of power supply circuits according to the processing liquid material combination, etc., and according to processing requirements, it has been used for switching selection or combination by a switching device (for example, See Patent Document 1-2.).

  An example of the power supply apparatus as described above will be described in the case of the power supply apparatus for a wire electric discharge machine shown in FIGS. Reference numeral 1 denotes a wire electrode that can be updated and moved in the axial direction between a pair of positioning guides 2A and 2B with a predetermined tension applied. Reference numeral 3 denotes a work stand 4 placed on an XY cross table (not shown). Is a workpiece to be opposed to each other through a minute discharge gap from a direction substantially perpendicular to the wire electrode axis direction, and is intermittently applied between the two under the processing liquid supply means by a processing liquid supply means (not shown). The machining is performed by generating an electric discharge by a machining voltage such as a simple voltage pulse.

  Then, a machining voltage for processing the workpiece first in the previous process, that is, an intermittent voltage pulse is supplied from the power supply circuit 5 for wire electric discharge machining in the illustrated example to the coaxial as the power supply connection lines 11A and 11B. Alternatively, it is supplied and applied between the wire electrode 1 and the workpiece 3 through a shielded wire or, further, to the lead wire in the vicinity of the discharge gap, preferably using a winding wire. The power supply circuit 5 comprises a series circuit of a DC voltage source 6A, a plurality of electronic switch elements 6B such as MOS-FET transistors connected in parallel according to the current capacity, a current limiting resistor 6C and a reverse voltage preventing rectifier 6D. The most conventional intermittent voltage pulse generation and supply circuit 6 is connected to the power supply connection lines 11A and 11B so as to be parallel to the discharge gap, and the intermittent voltage pulse is switched to the switching element 6B by the pulse controller 7. It is generated as desired by the control.

That is, as the control device portion of the switch element 6B of the control device 7, a constant ON time signal τ _ON and OFF which are set in advance are selected except when the switch element 6B is changed and controlled by the discharge gap detection information. In the case where the voltage pulse is controlled and supplied by repeating the time signal τ _OFF alternately and regularly, the on-time signal of the switch element 6B is supplied to the discharge gap until the discharge starts in the discharge gap. Starts measurement of the on-time signal from the start of discharge in the discharge gap after the start of voltage pulse application to increase as a function of the start delay time, that is, to set the discharge duration of each discharge pulse to a set constant value, and the measurement is completed Therefore, the switch element 6B is turned off to control the shift to the off time. In the following description, the latter case is mainly described. That is, the power supply circuit is not be construed as being limited thereto.

  In the power supply circuit 5, in addition to the machining voltage pulse supply circuit 6 by turning on and off the switch element 6B, the discharge current amplitude 1p of the discharge pulse by the circuit 6 is increased, thereby increasing the machining average current. Thus, a pulse current amplifier circuit or current pulse supply circuit 8 for further increasing the processing speed is provided in parallel with the circuit 6 as a series circuit composed of a variable DC voltage source 8A, a switch element 8B, and a reverse voltage prevention rectifier 8C. The current pulse supply circuit 8 is a non-resistance circuit or a switch having no so-called current limiting resistor in its series circuit so as to output a steep rising high current when the control device 7 turns on the switch element 8B. In addition to a minute detection resistor for the operation of the current controller 7A of the switch element 8B provided in the control device 7 to prevent the element 8B from being damaged, a current control is provided. Resistance is a circuit 8 is not inserted.

  Since the on-time signal of the switch element 6B or the on-time signal from the start of discharge is within several tens of μs at most and usually within several μs in wire electric discharge machining, the switch element 8B is applied by the circuit 6. Even if it is turned on during an on-time signal that is activated by detecting the start of discharge in the gap by a voltage pulse, damage can be avoided from the switch element 8B or at least the transition time to the saturation region operation of the circuit 8 or the like. In some cases, the operating region of the switch element 8B is an unsaturated region, or at least the range in which the current of the circuit 8 is sufficiently smaller (usually a fraction) than the saturation current value of the switch element 8B is the operating region. If the condition is set, the switch element 8B or the circuit 8 is preferably sharp because the current-off characteristic is sharp and steep.

  In the example of the power supply device shown in the figure, the power supply circuit 5 includes another series circuit of a variable DC voltage source 9A, a switch element 9B, a current limiting resistor 9C, and a reverse voltage prevention rectifier 9D, that is, a second circuit. A voltage pulse supply circuit 9 is provided, and the second voltage pulse supply circuit 9 is used as desired by the open / close switch 9E. For example, the DC voltage source 9A has a normal output voltage. The constant voltage source 6A (approximately 80 to 120V) is variable and has a voltage value equal to or greater than (approximately 80 to 280V), and the current limiting resistor 9C has a large setting with respect to the resistor 6C. The switch element 9B is controlled by the pulse control device 7, for example, by controlling on / off synchronous application with the switch element 6B, etc., thereby increasing the average machining voltage of the gap. Together to promote start, a secondary power supply for the operation of such sustaining the discharge gap wide servo control by the gap voltage detection, not essential to the practice of the electric discharge machining.

  The above-described current pulse supply circuit 8 is a power supply circuit 5 together with the voltage pulse supply circuit 6 and the normal circuit 9, and the first cut processing step for processing the workpiece 3 first, the dimensions of the processing after the first cut processing step, It is used in a second cut processing step for performing shape accuracy processing, that is, a processing step using intermittent voltage pulses as the processing voltage, and the gate input is connected to the control device 7 by a changeover switch 8E. The control related to the circuit 6 is performed, but after finishing the second cut machining process, finishing processing of 1 to 2 of machining surface roughness using a high-frequency AC voltage as a finishing machining process is performed. When moving to a process (for example, a third cut process or a further force cut process), the voltage pulse supply circuit 6 and 9 is disconnected by the open / close switches 6E and 9E as necessary, and the changeover switch 8E is switched to the gate signal circuit 8D side of the intermittent pulse to make the current pulse supply circuit 8 function as a high frequency pulse (current) generation circuit 10. is there.

  When the switch element 8B is connected to the gate signal circuit 8D by the changeover switch 8E, the control device 7 is configured not to output the on / off control signals of the switch elements 6B, 8B and 9B.

  At this time, the high-frequency coupling transformer 13 provided between the high-frequency pulse generation circuit 10 and the discharge gap and the second cut processing step for obtaining the dimensional and shape accuracy are shifted to a finishing processing step such as surface roughness. The circuit device 12 housed in a box-shaped box composed of the circuit switching opening / closing switch 14 is used for the following configuration and switching.

  That is, the high-frequency coupling transformer 13 converts each intermittent high-frequency pulse current output from the high-frequency pulse generation circuit 10 into one cycle of high-frequency AC voltage, and has a high magnetic permeability made of high-frequency ferrite or the like. The primary winding 13B and the secondary winding 13C are provided on the ring core 13A, the winding ratio is 1: 1 to 3, preferably 1: 1 to 2, and the number of turns is 1 to 5 turns, preferably 1 ~ 2 turns, secondary winding 1 ~ 12 turns, preferably 1 ~ 4 turns, high-frequency response for finishing with a small number of turns to enable high frequency response, and if anything, high voltage and low current For the purpose of obtaining an AC voltage, the secondary winding is wound so that the number of windings is equal to or greater than that of the primary winding.

  Next, the output of the high frequency pulse generation circuit 10 and the connection and switching configuration of the circuit device 12 between the power supply connection lines 11A and 11B between the discharge gap formed by the wire electrode 1 and the workpiece 3 will be described. An open / close switch that connects / disconnects the secondary winding 13B to / from the output of the high-frequency pulse generation circuit 10 and an open / close switch that connects / disconnects the secondary winding 13C to / from the discharge gap are the wires at both ends of the high-frequency pulse generation circuit 10 and the discharge gap. Connected to both of the output lines on the high-frequency pulse generation circuit 10 side of the power supply circuit open / close switches 14A and 14B provided in the circuit portions of the power supply connection lines 11A and 11B connected between the electrode 1 and the workpiece 3 respectively. The primary winding on / off switch 14C inserted in one or both of the connection circuits, and the output ends of the secondary winding are more discharged than the feeding circuit on / off switches 14A and 14B. Comprising a secondary winding off switch 14D was inserted into one or both of the connection circuit between connecting the wire electrode 1 in both of the workpiece 3 at the side.

  The two feeding circuit opening / closing switches 14A and 14B and the primary winding and the secondary winding opening / closing switches 14C and 14D include the latter opening / closing switches 14C and 14D when the former opening / closing switches 14A and 14B are on. In order to achieve this purpose, the power supply circuit on / off switches 14A and 14B are off and the primary and secondary winding on / off switches 14C and 14D are on. In this case, a power supply circuit for finishing processing using a high-frequency AC voltage used in a later processing step is configured. In addition, in the drawing, each of the primary winding and the secondary winding is provided as one open / close switch, and the number of changeover switches provided is the smallest. As a matter of course, various switching circuit configurations can be realized depending on the number of switches.

  FIG. 5 shows that the machining power supply circuit of FIG. 4 is used as a finishing power supply circuit for a later machining process, that is, the opening / closing switches 6E and 9E are turned off as necessary, and the gate signal circuit 8D is turned on by the changeover switch 8E. The timing chart when the high-frequency pulse generation circuit 10 is operated, the power supply circuit open / close switches 14A and 14B are turned off, and the transformer primary and secondary winding open / close switches 14C and 14D are turned on, respectively, is almost ideal for two cycles. A is a high-frequency gate signal output from the intermittent pulse gate signal circuit 8D to turn on / off the switch element 8B, and b is output from the high-frequency pulse generation circuit 10 based on the gate signal. The current pulse c to be supplied to the primary winding 13B of the transformer 13 and c is induced to the secondary winding 13C based on the pulse current. By discharge gap voltage waveform when discharge occurs in the discharge gap based on the high-frequency AC voltage and said high-frequency AC voltage applying applied to the discharge gap, d is an example of the discharge current of the discharge gap.

The intermittent pulse gate signal output from the gate signal circuit 8D is shown as T _ON = 100 ns and T _OFF = 1.0 μs in the drawing in the case of advanced finishing more than a certain level, and approximately T _ON = The condition is set so that T _OFF ≧ 0 preferably within the range of 50 ns to 1000 ns or less, T _OFF = 500 ns to 10 μs or several tens of μs, and the AC voltage of c is connected to each other. It is. The output current pulse waveform b of the high-frequency pulse generation circuit 10 is not changed before the switch element 8B enters the saturation region operating state of the rising current in which the current of the circuit 8 is at least sufficiently smaller than the saturation current value of the switch 8B. The signal a is turned off, and the switching element 8B or the circuit 8 is shown as having been cut off at high speed.

Further, the high-frequency AC voltage of the secondary winding 13C of FIG. C is, according to recent tests, high permeability Mn—Zn ferrite, Ni—Zn ferrite, etc. having an outer diameter of about 55 mmφ and an inner diameter of about 30 mmφ. A core 13A in which two ferrite toroidal cores (for example, PC50T40 × 16 × 24 made by TDK) are stacked, a Teflon-based resin-coated conductor having a cross section of about 3.5 mm ^{2 is} a primary winding 13B: one turn, a secondary winding 13C: When the turn is 2 turns, the DC voltage source 8A has an output of about 60V and is about 150 to 170V positive and negative, respectively, and the voltage source 8A has an output of about 25V and positive and negative respectively 60 to 65V. A high-frequency high-frequency AC voltage suitable for finishing processing (third cut and force cut) can be obtained, and as shown in the discharge current waveform d, the first half wave of one cycle of AC voltage When the discharge occurs, it will be followed by the discharge occurs at the half-wave of the next opposite polarity, it is possible to average machining current to advance the finished at 1A before and after about a smaller value.

  For example, by processing the processed surface finished to about 10 to 13 μm Rmax by the second cutting of the previous processing step by the high frequency AC voltage of about 150 to 170 V and about 1 MHz, with the third cut of the subsequent processing step. , About 3.5 μm Rmax can be finished, and further, it is finished to about 1.5 μm Rmax by force-cutting with the high-frequency AC voltage of about 60 V.

In the case where the pause time AT _OFF between the high-frequency AC voltages c is smaller, or is set to be continuous, when the average voltage of the discharge gap is detected at a voltage equal to or lower than a predetermined level, or a predetermined set cycle It is natural for safety that it is necessary to stop the on / off of the switch element 8B for every 10 to 100 μs (every 100 μs to 10 ms), for example.

  6, 7, and 8 are schematic external views of the circuit device 12, an internal layout diagram, and an explanatory diagram of a configuration example of the open / close switch 14. In FIG. 6, the work stand 4 is the wire electrode 1. The circuit device 12 is provided adjacent to the work stand 4 and is located in a processing liquid receiving pan or processing tank on an XY table (not shown) orthogonal to the axis (Z axis).

  The circuit device 12 is formed of a rectangular parallelepiped box-like body. As shown schematically in the drawing, the circuit device 12 has a transformer chamber 12A portion that houses the high-frequency coupling transformer 13 in the center, and opposite ends of the transformer chamber 12A. Are provided with switch boxes 12B and 12E for power supply circuit open / close switches 14A and 14B, and switch boxes 12C and 12D for open / close switches 14C and 14D for primary winding and secondary winding, respectively. Connection terminals 15A, 15B to which the output of the pulse generation circuit 10 is connected, and connection terminals 15C, 15D, 15E for connecting the output of the transformer secondary winding 13C to the discharge gap between the wire electrode 1 and the workpiece 3 are provided. Provided.

  The output of the high-frequency pulse generation circuit 10 in the power supply circuit 5 is connected to the terminals 15A and 15B via a coaxial or shielded wire 16 with reduced inductance, and the terminal 15C is a positioning guide 2A and 2B. The upper and lower guide blocks 18A and 18B that store the wire or the closer one of them (the lower side in the drawing) guide block 18B is required for mutual movement between the power supply to the wire electrode 1 (not shown) The shortest length, preferably connected by a wire 16A, and between the terminals 15D and 15E and the work stand 4, the terminals 15D and 15E are short-circuited and one output line is used, or two as shown in the figure. The output line 16B is preferably connected using the shortest wire.

  Thus, in the circuit device 12, the high frequency having the sharp and sharp rising and falling characteristics shown in FIG. 5 b from the output of the high frequency pulse generation circuit 10 to the primary winding 12 B of the high frequency coupling transformer 13. Although it is relatively easy to supply the pulse current, it is difficult to supply and apply the steep high-voltage high-frequency AC voltage c induced in the secondary winding 13C to the discharge gap as it is. In order to solve such a problem, the circuit device 12 is configured in one box-like body, and the circuit device 12 is disposed at a position closer to the discharge gap. The work stand 4 is disposed adjacent to the work stand 4 or closer to the processing part that does not interfere with the processing of the side of the processing tank, the surface of the column on the processing tank side, or the processing head for holding the guide blocks 18A, 18B, etc. The connection lines 16A and 16B using a shoreline or the like are made shorter.

  The former connection line 16A in the connection lines 16A and 16B requires a certain length for mutual movement for processing, but the latter connection line 16B is a switch box provided with terminals 15D and 15E. A part or the whole of the end face of 12C (the face on which the terminals 15D and 15E are provided or the face facing the front face of the work stand 4) is used as a terminal metal plate in which the terminals 15D and 15E are provided, The terminal metal plate may be screwed to, for example, the front edge of the work stand 4 or may be attached by welding to measure the electrical and mechanical connection.

  FIG. 8 shows a cross section of the secondary winding on / off switch 14D as an example in the description of the configuration of the on / off switch 14. The configuration is a butt contact type on / off switch as an overall configuration, In the cylindrical switch box 12D, there is a piston-like fixed contact 14DS connected to the external connection terminal 15D, and a piston-like movable contact 14DM that advances and retreats in a direction facing and opposes to this, and a piston-like movable contact 14DM. The forward / backward movement of the movable contact 14DM is performed by switching control of a fluid pressure source (not shown) connected to the pressure fluid supply / discharge holes 20A and 20B penetrating the wall of the box 12D. Each of the contacts 14DS and 14DM is adjusted such that a contact material energizing plate 21 is interposed between the butted contact surfaces 21 so that the energization of the high-frequency power is satisfactorily maintained. For fluid pressure operation, seals 19A, 19B, 19C such as O-rings are provided. In order to drive the movable contact 14DM to move forward and backward, in addition to the fluid pressure source described above, various types such as a combination of an electromagnetic force, a spring, a motor, a link, a rack, or a crank can be used.

  As described above, the open / close switch 14 of FIG. 8 is the secondary winding open / close switch 14D of FIG. 4, and therefore, a primary winding open / close switch 14C having substantially the same configuration is provided. 14A and 14B are substantially the same, and a total of four are required.

  Each of the open / close switches 14A, 14B, 14C, and 14D has a connection line at any portion between the output end of the power supply circuit 5 and the discharge gap via the power supply connection lines 11A and 11B as described above. Built-in wiring that is as short as possible and taking care not to increase the inductance, is integrated with the circuit device 12 and is compact, and is located in the immediate vicinity of the discharge gap around the processing tank. A high-frequency coupling transformer 13 in 12A is provided so that it can be cooled by circulating or circulating the machining fluid.

  However, each of the open / close switches 14A, 14B, 14C, and 14D has an axially movable piston rod 14DP having an energizing terminal on the other end side coupled to the piston-like movable contact 14DM and made of an insulating material. Since the hole 12DH of the cylindrical switch box 12D is exposed to the outside while being sealed with the sealing material 19C, it is contaminated by the arrival and intrusion of external contaminants including the aqueous processing liquid. Electropitting, wear, and damage on the piston rod 14DP, the hole 12DH, the seal materials 19C and 19B, and the piston-like movable contact 14DM are inevitable, resulting in poor insulation and loss of electrical energy. As a result, the desired high-frequency current, high rise and steep rise, and high peak current pulses cannot be obtained.

  In order to solve these problems, the present inventors have proposed an improved switch device for switching an electric discharge machining power circuit (see, for example, Patent Document 3).

  That is, one of them is configured to house and seal not only the piston-like movable contact 14DM but also the entire external exposure of the movable part including the piston rod 14DP connected to the cylinder-like switch box 12D. As shown in FIG. 9, a storage body 21 made of a sealed cylinder-like insulator installed in the electric discharge machining liquid and a cylinder chamber 21A formed in the storage body 21 are provided so as to be capable of reciprocating in the axial direction. The movable body 22 is composed of a piston-like flange portion 22A on one end side and a piston rod-like rod portion 22B on the other end side, and terminals 23T and 24T are externally connected to both ends of the movable body 22 in the moving direction. Fixed terminal conductors 23 and 24 which are exposed to each other, and the end portions of the shaft-like body outer peripheral surface passing through the storage body 21 in the axial direction and the inner peripheral surfaces 23B and 24B are in close contact with each other. And it has a configuration that is fixed.

  The pressure contact and separation of the one terminal 23 and the piston-like flange portion 22A in the illustrated state are such that the axial movement of the flange portion 22A in the cylinder chamber 21A is the piston provided on the outer periphery of the flange portion 22A. While the above-described pressurized contact energization and disconnection energization are performed by supplying and discharging compressed air to and from the fluid pressure supply / discharge ports 21B and 21C with respect to the cylinder chamber partitioned by the cylinder 22C, the shaft together with the flange portion 22A The rod portion 22B moving in the direction and the terminal conductor 24 are connected to and separated from each other by coaxially inserting the rod portion 22B into the body portion 24C extending in the axial direction so as to have the shaft-like outer peripheral surface 24B. In the example shown in the figure, the rod 22B and the terminal conductor 24, that is, the terminal 24T are always connected regardless of the axial movement of the rod 22B. Those that are configured in a conductive state.

  Note that the hatched portion between the outer peripheral surface of the rod portion 22B and the inner peripheral surface of the hole 24A of the terminal conductor 24 and the contact surface of the flange portion 22A and the terminal conductor 23 are hatched. The member S2 shown in FIG. 2 is a current-carrying plate (for example, the contact material made by Solton shown in FIGS. 2 and 3 of the aforementioned Patent Document 3 and the trade name “Electro” Mate ") is interposed as a cylindrical body or a disk or donut plate.

If the configuration of the switch box 12B, 12C, 12D, 12E, etc. is the configuration of the storage body 21 shown in FIG. 9, there is no movable portion and no contact portion with the movable portion on the outer peripheral portion, and the movable portion is completely inside. The problem pointed out in the paragraph [0028] is largely solved, and the number of switch boxes 12B, 12C, 12D, etc. pointed out in the paragraph [0026] are also described in FIG. As shown in FIG. 9 as an improvement, a cylindrical doughnut-shaped third terminal conductor 25 is provided between the flange portion 22A and the terminal conductor 24 so as to divide the cylindrical housing 21 in a direction perpendicular to the axial direction. The rod portion 22B of the movable body 22 is inserted into the hole 24A of the terminal conductor 24 in a state where the rod portion 22B is inserted into the hole 25H of the terminal conductor 25 in a non-contact manner, and the flange portion 22A is separated from the terminal conductor 23. In some cases, the surface on the opposite side in the axial direction of the flange portion 22A provided with the doughnut-shaped energizing plate S3 is configured to be in pressure contact with the third terminal conductor 25 so that the terminal conductor 25 is independent of the outer peripheral surface. Thus, the terminal 25T is provided, and the switching between the terminal 24T and the terminal 23T or 25T can be performed by one operation, and this kind of power supply circuit switching device has been completed.
JP-A-7-227718 JP 7-266138 A JP 2000-71125 A JP-A-5-154718

  As described above, during electrical discharge machining, it has been used as one that suitably functions as a switching device for switching between different types of power supply circuits provided in the power supply device, and further switching and using in combination. However, recently, in addition to the demand for improving the performance of the electrical discharge machine itself, for example, there are strict and diverse demands on dimensions, shape, accuracy, etc., as well as competition issues with dissimilar machine tools such as a machining center. In addition to the types and number of power supply circuits to be mounted, the demand for ultra-high speed has been increasing, and power supply capacity has been increasing.

  Considering the power supply circuit switching device as described above from this point of view, the energization plates of the contact materials such as S1, S2, and S3 in the switching device are repeatedly applied to the contact portion due to repeated switching use. Although it depends on the use situation, it has come to be damaged in a relatively short time.

  In addition, it has been used to process large currents as mentioned above, such as ultra-high speed. However, when a large current is applied, heat generation increases and the cylindrical housing of the insulating material is deformed. There has also been a problem of causing malfunctions.

  And, as a result of investigation, in the portion where the current plate of the contact material is interposed, such as between the pressure contact surface of the piston-shaped flange and the current contact surface of the terminal conductor with respect to the contact point, contact points are provided on both sides of the current plate. Since the current is applied via the contact surface, the contact resistance is larger than when the surface of the flange and the surface of the terminal conductor are pressed and contacted with high surface accuracy, leading to an increase in the amount of heat generated. It was what it was.

  In the future, the use of a large current power source is unavoidable in any case, so the application of cooling means is unavoidable. In terms of the form of circulation, etc., it is structurally difficult, and various attempts have been made for fixed terminal conductors. Therefore, there is a problem that it is difficult to impart a large cooling capacity, and the purpose is difficult to achieve.

  Therefore, the present invention abolishes the use of the aforementioned contact material energizing plate, and also improves and rationalizes the structure of the contact breaking portion accompanying the use of the energizing plate, thereby providing a durable switching device and reducing contact resistance. Reduced heat generation, increased discharge current peak, and effective application and disposition of the cooling mechanism for the switching device, thus obtaining a switching device for a power circuit for electric discharge machining that functions efficiently even in high load applications For the purpose.

The object of the present invention is as follows: (1) a power supply device having a plurality of different types of machining power supply circuits for electric discharge machining, and an electric discharge machining switching device provided between machining portions between an electrode and a workpiece; A cylindrical chamber is formed on both sides independently by inserting a coupling body made of a conductor of a terminal material that divides the cylindrical box body in a direction perpendicular to the axis and is coupled to the central portion of the cylindrical box body. A piston made of a conductor material for terminals is inserted into both the cylinder chambers, and the cylinder walls at the outer ends of the cylinders are moved in the axial direction in the airtight state on the outer surfaces of the pistons. Piston rods for terminal conductors are provided, and on each opposing surface of each piston and the conductor of the terminal member connecting both the cylinder chambers, axial fitting is performed to press fit and release. Complementary taper protrusion and tape The switching device and the hole is provided with 2 Konami設, tapered pistons of the respective switching device in the by supply and discharge switching of pressurized fluid to both cylinder chambers, on one side via the conjugate from a pressurized press fit engagement between the projection and the tapered bore to switch to the pressurized圧勘case of the tapered projection and the tapered hole on the opposite side, is driven axial movement Rutotomoni, piston and other in one switching device The switching device is driven by the piston at the same time , and is achieved by a switching device for an electrical circuit for electric discharge machining in which the outer peripheral side surface of the conductor of the terminal material and each outer end of the piston rod are provided with terminal portions for electrical lead connection. Is done.

The above-mentioned object of the present invention is as follows. ( 2 ) In the switching device for each electrical circuit for electric discharge machining arranged in parallel at the top and bottom, the combination composed of the conductors of each terminal material is located at the center in the left-right direction. Thus, when the pair of pistons with piston rods facing each other through the combined body of one switching device moves leftward by driving, the pair of pistons with piston rods of the other switching device simultaneously moves rightward. This is achieved by using the electric discharge machining power supply circuit switching device according to ( 1 ), wherein the drive is controlled.

Also, the object of the present invention is to: ( 3 ) connect one input line P3 output from a power supply device having a plurality of different types of power supply circuits for processing by a coaxial cable or shield wire to one piston rod of one switching device; While connecting to the P3 terminal, the other input line P4 is connected to the P4 terminal of the conductor of the terminal material of the other switching device, and the output line P3 on the one worktable side of the line between the machining parts is switched to the one The output wire P4 on the other wire electrode side is connected to the P4G terminal of the other piston rod of the other switching device, and connected to the P3W terminal of the conductor of the terminal material of the device. The input of the primary winding of the high-frequency coupling transformer of the ring core that converts the output DC pulse of the high-frequency pulse generating circuit output from the lines P3 and P4 into an AC pulse is connected to the P3 terminal. To the square of one of the piston rod terminal of the switching device, also according to the the output secondary winding formed by connecting to the terminal of the other piston rod of the P4G terminal and one switching device (2) This is achieved by providing a switching device for a power supply circuit for electric discharge machining.

  According to the present invention (1), the switching contact portion of the electric circuit of the switching device is formed on the conductor surface of the fixed terminal material that is the wall of one end in the cylinder chamber and the surface of the piston that moves forward and backward. A conventional example in which bending stress is applied by repeated opening and closing because the taper projection is a tapered hole with a complementary size and shape that moves in the axial direction by fluid pressure drive and pressurizes and disengages. Since there is no energizing plate or the like, durability is improved.

  In addition, even if the manufacturing accuracy of the piston or cylinder is somewhat lowered, or even if misalignment occurs due to heat generation or durability problems, contact energization is performed with a taper protrusion and a taper hole of complementary dimensions and shape. Is moved by fluid pressure driving and is performed by press-fitting and disengagement, so that there is an advantage of a large allowance for ensuring good contact energization.

  In addition, since a current-carrying plate or the like as in the conventional example is not used between the contacts, the number of contacts in the series circuit is changed from one place to one place in direct contact, the circuit resistance is reduced, and the contact is made between the tapered surfaces. Therefore, the contact pressure between the contacts becomes larger than the thrust applied to the piston, and as a result, the contact resistance is reduced and the heat generation can be reduced. Furthermore, as a result, the current and peak reduction of the electric discharge machining can be avoided, the electric discharge machining performance is improved, the heat loss is reduced and the power loss is reduced.

Further, according to the present invention ( 2 ) and ( 3 ), there is provided a switching device for an electric discharge machining power circuit configured by using the electric discharge machining circuit switching device of the present invention, wherein a plurality of different types of power supplies are provided. The circuit can be switched and connected in a suitable and reliable manner, and the connection can be released, and the performance of the target power supply circuit can be reliably exhibited as intended.

  FIG. 1 is a longitudinal side view of an embodiment of a switching device portion of a power supply circuit for electric discharge machining according to the present invention. Electric circuit wiring and high-frequency intermittent DC input from output terminals P3 and P4 of a power supply circuit (not shown) A conversion circuit for the high-frequency coupling transformer 13 of the ring core 13A having an input primary winding 13B and an output secondary winding 13C for converting a current pulse into a high-frequency AC pulse and outputting it to the interpolar wires P3 and P4 is added. It is shown. 2 is an external perspective view of an embodiment of the same switching device portion as FIG. 1, and FIG. 3 is a perspective view of a longitudinal side surface.

  Further, in the longitudinal side view of the switching device portion of FIG. 1, the portion surrounded by a one-dot broken line and designated by reference numeral 30 is a book equivalent to the switching device of the electric circuit for electric discharge machining described with reference to FIG. 9 or FIG. 1 shows one (upper) switching device of an embodiment of the invention, in which a cylindrical box 31 made of an insulating material such as a synthetic resin has one box 31A perpendicular to the axis at the center in the axial direction. The other box body 31B is divided into a terminal member, for example, a conductor combination body 32 made of a brass block-like body, so that one and the other cylinder chambers 31AS and 31BS are formed in series on one axis. ing.

  The one and the other cylinder chambers 31AS, 31BS are inserted with one and the other pistons 33A, 33B made of a conductor material for terminal, for example, stainless steel, on the outer surfaces of the pistons 33A, 33B. The piston rods 33AR and 33BR are integrally formed, and the piston rods 33AR and 33BR are provided in an axially penetrating manner at the outer wall of each of the cylindrical boxes 31A and 31B. It is driven by switching control of the pressurized fluid such as compressed air from the supply / discharge ports 34A and 34B and moves together with the pistons 33A and 33B in the desired axial direction.

The pistons 33A and 33B are axially driven by fluid pressure driving on the opposing surfaces of a combined body 32 that combines the one and the other pistons 33A and 33B and the one and the other cylindrical box bodies 31A and 31B. Tapered protrusions 32A and 32B having a complementary size and shape that move and press-fit and disengage, and tapered holes 33AH and 33BH that narrow toward the bottom are preferable. Is provided so that there is a taper protrusion on the side of the coupling body 32, and the meeting surface area of the taper surface of the taper protrusions 32A and 32B and the taper surface of the taper holes 33AH and 33BH serves as a contact surface of the contact, thereby driving the fluid. It joins in a pressurized state with the thrust by.
More specifically, the frustoconical taper protrusions 32A and 32B are shorter than the tapered holes 33AH and 33BH formed so as to taper at a substantially constant taper angle from the entrance to a predetermined depth. It is preferable to use a tapered protrusion having the truncated cone on the top for good sliding contact between both tapered surfaces. Furthermore, the recess shown at the top of the taper protrusion, or three or more radial grooves or cross grooves from the center or center recess, corresponding to the taper hole's tightening action, contracted in a staggered manner in the press-fitted state. It is intended to maintain stable contact, but is not essential.

  Further, at a desired portion of the outer peripheral surface of the coupling body 32, the one terminal line P3 of the power supply interelectrode line around the processing portion is connected to a work stand where the workpiece is installed. A P3W terminal for attaching the other end input side terminal is provided, and switching and selection from a plurality of different types of power supply devices for processing at the rear end portions of the one and the other piston rods 33AR and 33BR, etc. Then, a P3 terminal to which a tip terminal of one input line P3 output by a coaxial cable or a shielded wire is attached to the one piston rod 33AR, and the input primary winding 13B of the high-frequency coupling transformer 13 is connected to the P3 terminal. One of the terminals is connected. One terminal of the output secondary winding 13C of the high-frequency coupling transformer 13 is connected to the terminal of the other piston rod 33BR.

  As shown in FIGS. 2 and 3, the coupling body 32 made of the conductor of the terminal material is used to prevent the coupling body 32 from being heated and heated by an electric discharge machining current such as a high-frequency direct current pulse or alternating current. A flow path 32C is formed in which a cooling liquid is circulated to exhibit a predetermined cooling capacity, and a configuration in which cooling liquid supply and discharge pipes 32D and 32E are connected to desired portions on the outer peripheral surface is adopted.

  In order to switch the power supply circuit functionally as a switching device for the machining power supply circuit, to perform the switching combination or the switching selection operation, the switching device for the electric circuit for electric discharge machining of the present invention is one (upper) described above. In addition to the electric circuit switching device 30, the other (lower) electric circuit switching device 40 having the same configuration as that of the device 30 shown in the figure is required. Therefore, when both the switching devices 30 and 40 are mounted on a mounting plate 35 attached to a processing tank wall or a work stand as shown in the figure, the one and the other switching devices 30 and 40 are arranged upward and downward. In the illustrated case, the transformer housing chamber 12A of the high-frequency coupling transformer 13 which is a part of the power circuit for generating a high-frequency alternating-current pulse for finishing is further connected to a lead wire. From where it is necessary to shorten wiring length that can be provided to the processing unit nearest position of such machining tank.

  Thus, the switching device 40 for the other power supply circuit on the other side is different from the switching device 30 described above in the manner of arrangement, circuit wiring, etc., and the structure itself of each part is the same. Since it is substantially the same, the explanation about the structure and the like will be omitted except for a part.

  And of course, it is premised on the arrangement of each switching device 30 and 40, which will be described later, the configuration of the electric circuit, and the wiring. The switching devices 30, 40 are configured such that the coupling bodies 32, 42 made of the conductors of the terminal members are fixedly positioned at the center in the left-right axial direction of the cylindrical boxes 31, 41. When the pair of pistons 33A, 33B facing each other through 32 moves leftward by fluid pressure driving, the pair of pistons 43A, 43B of the other switching device 40 simultaneously moves rightward, and the switching device 30 is coupled to the coupling body 32. The pressure fitting contact between the taper protrusion 32A of the piston 33A and the taper hole 33AH of the piston 33A is switched to the pressure fitting contact between the taper protrusion 32B on the opposite side to the left and the taper hole 33BH of the piston 33B. The lower switching device 40 has a pressure fitting contact between the taper protrusion 42B of the coupling body 42 and the taper hole 43BH of the piston 43B, and a pressure fitting between the taper protrusion 42A on the opposite side to the right and the taper hole 43AH of the piston 43A. A drive circuit for supplying and discharging fluid pressure is connected to each cylinder chamber 31AS, 31BS, 41AS, 41BS so as to switch to contact.

  Then, the other input line P4 that outputs to the desired portion of the outer peripheral surface of the coupling body 42 on the switching device 40 side of the other (lower) power supply circuit from the power supply device through a coaxial cable or a shielded wire by selection or the like. And a terminal provided at the rear end of one piston rod 43AR is connected to the other terminal of the input primary winding 13B of the high-frequency coupling transformer 13, and The terminal P4G terminal provided at the rear end of the other piston rod 43BR is connected to the other terminal of the output secondary winding 13C of the high-frequency coupling transformer 13 and the tip terminal of the power supply interelectrode wire around the processing portion. The other end input side terminal of the other inter-electrode line P4 connected to the current-carrying piece provided in the upper and lower guide blocks for electrode positioning guidance is attached.

  The switching setting states of the switching devices 30 and 40 shown in FIG. 1 are the same as the input from the power supply circuit 5 via the input line P4, that is, the voltage or current increase pulse due to various voltage pulses or switching combinations. This is a setting to output to the inter-electrode lines P3 and P4 of the processed part. To explain this, the input line P3 is connected to the terminal of one piston rod 33AR, the pressure contact between the taper hole 33AH of one piston 33A and the taper protrusion 32A of the coupling body 32, and the P3W terminal of the coupling body 32. To the interpolar line P3 (workpiece), from the other interpolar line P4 (wire electrode) through the P4G terminal of the other piston rod 43BR, and the taper hole 43BH of the other piston 43B and the taper of the coupling body 42. Since the pressure contact with the protrusion 42B and the power output line P4 are connected to each other through the P4 terminal of the combined body 42, there are 3 contact points for each of the forward path (P3-P3W) and the return path (P4-P4G). The number of points is smaller than the seven points in the conventional example (see Patent Document 3) using the switching device of FIG. 10, and both the impedance and the electrical resistance of the forward and backward circuits are measured. If, with respect to prior art 11Emuomega, it was found to be able to significantly reduce the present invention 1 M.OMEGA. In contrast to the case where the current-carrying plate of the conventional example is used and the case where the taper projection and the taper hole are in contact with each other, the electrical resistance is reduced to about 1/4 in the case of the latter invention due to the contact area. It was. With a machining current of 50 A, the current peak rises with a pulse of 1 μs when a current probe is attached to the inter-electrode wire, which is 550 A / μs in the circuit of the present invention compared to the conventional example of 480 A / μs, which improves the machining speed Be expected.

  Next, when the switching settings of the switching devices 30 and 40 are reversed, the high-frequency DC current pulse inputs P3 and P4 from the power source are converted into high-frequency AC pulses by the high-frequency coupling transformer 13, and the interpolar line P3, The circuit configuration functions to output to P4. That is, the input line P3 is connected to one terminal of the input primary winding through the P3 terminal of one piston rod 33AR, and the other terminal of the primary winding is connected to the piston 43A from the terminal of the lower piston rod 43AR. The pressure contact between the taper surface of the taper hole 43AH and the taper surface of the taper protrusion 42A of the coupling body 42 is connected to the other input line via the P4 terminal of the coupling body 42. On the other hand, one terminal of the output secondary winding is connected to the terminal of the upper other piston rod 33BR, and the tapered surface of the tapered hole 33BH of the upper piston rod 33B and the tapered protrusion 32B of the coupling body 32 are connected. Through pressurization contact between the tapered surfaces, it is connected to the interpolar line P3 for the P3W terminal of the combined body 32, and the other terminal of the secondary winding is connected to the P4G terminal of the lower piston rod 43BR. The other end of the P4G terminal is connected to the machining portion by an inter-electrode line P4.

  As described above, the electric circuit switching device of the present invention does not cause a problem of durability due to repeated use, because it does not interpose a current contact plate or the like for improving contact between the contact to be pressed and released. The number of contact surfaces that lead to an increase in electrical resistance and impedance is reduced, and therefore heat generation is reduced, so that the problem of thermal damage is reduced.In addition, switching for switching is performed between the taper protrusion and the taper hole made of the conductor of the terminal material. Since it is a pressure contact of the taper surface by pressure fitting, the contact conforms to the firm fixation, and the contact resistance is also reduced.

  In addition, the switching device of the present invention has a combined body composed of conductors of terminal materials at the center as described above, and the piston is advanced and retracted from both sides with respect to the combined body so as to make contact with and separate from each other. The structure is simple, the number of parts is small, it is easy to manufacture, the wiring of the electric circuit is also simple, and the additional structure of the cooling means is easy and the structure conforms to the display of the cooling capacity, etc. It has many advantages.

  It should be noted that the angle between the taper projection that forms and opens the circuit by closing and releasing the pressure contact between the coupling body and the piston and the taper surface that forms the taper hole. Thus, it is preferable because the contact contact pressure becomes larger than the thrust of the pressure contact, but it seems to be preferable that a slight slip occurs between both tapered surfaces by the applied pressure. On the other hand, if the taper angle is too small, for example, about 20 ° or less, it is not preferable because the projection side may protrude into the hole side in a wedge shape or the like and become difficult to come off. In the above-described combination of materials according to the embodiment of the present invention, it was possible to operate satisfactorily with a taper angle of 30 °. Further, as in the above-described embodiment, the combination of the projecting taper protrusions is made of a soft brass material, whereas the piston material of the recessed taper holes is combined and set in a relationship of a hard SUS material. It is convenient without causing any problems in contact of the contacts when worn down.

  In the electrical circuit switching devices 30 and 40 described above, the piston rod that advances and retreats in the opposite direction is exposed to the outside in the rear, so that the machining fluid is introduced and discharged to cool the high-frequency coupling transformer. In the case where the switching device 30 or 40 is used by being attached to the attachment plate 35 together with an AC conversion circuit of a direct current pulse and disposed at a position closest to the electric discharge machining portion, for example, the switching devices 30 and 40 are further corrosion resistant from the state of FIG. It is recommended that it be covered with a stainless steel can and sealed.

  The present invention can be used as a power supply circuit switching device by being installed between the machine processing portion of an electric discharge machine and a power supply device having a plurality of power supply circuits that can be selected and combined.

1 is a longitudinal sectional view of an embodiment of a switching device portion of a power supply circuit for electric discharge machining according to the present invention, to which an electric circuit wiring is added and a circuit device which is normally attached and used. The external appearance perspective view of one Example of the same switching apparatus part and attached circuit apparatus as FIG. The perspective view of the vertical side view of one Example of the same switching apparatus part and attached circuit apparatus as FIG. An example of the power supply circuit for wire electrical discharge machining which has the several switchable power supply circuit of a prior art example. FIG. 5 is an example of an AC voltage and current waveform obtained from one of the power supply circuits of FIG. 4. The figure which shows the aspect of use of the circuit apparatus 12 of FIG. Explanatory drawing of the structure of the said circuit apparatus. Explanatory drawing of the structural example of the opening / closing switch 14. FIG. The cross-sectional top view which shows the structure of the switching apparatus of another prior art example. Moreover, the cross-sectional top view which shows the structure of the switching apparatus of another prior art example.

Explanation of symbols

30, 40 Electric circuit switching device for electric discharge machining.
31, 41 Cylindrical box.
31A, 41A; 31B, 41B One and the other cylindrical box.
31AS, 41AS; 31BS, 41BS One and other cylinder chambers.
32, 42 Combined body composed of conductors of terminal materials.
32A, 42A; 32B, 42B One and the other tapered protrusions.
33A, 43A; 33B, 43B One and the other piston.
33AR, 43AR; 33BR, 43BR One and the other piston rod.
33AH, 43AH; 33BH, 43BH One and the other tapered holes.
32D, 32E, plug for coolant supply / discharge path.
34A, 34B Pressure fluid supply / discharge plugs.
35 Mounting plate.

Claims (3)

In a power supply device having a plurality of different types of machining power supply circuits for electrical discharge machining and a switching device for electrical discharge machining provided between machining portions between an electrode and a workpiece,
The cylinder-shaped box made of an insulating material has an axially central portion, and a cylinder made of a terminal material conductor that divides the cylinder-shaped box in a direction perpendicular to the axis and is coupled to each other, and cylinders are independently provided on both sides. Chambers are formed, and pistons made of conductor materials for terminals are inserted into the cylinder chambers, and the cylinder walls at the outer ends of the cylinders are sealed in the axial direction in the airtight state on the outer surfaces of the pistons. Piston rods for moving terminal conductors are provided, and the respective opposing surfaces of the pistons and terminal material conductors connecting the cylinder chambers are moved in the axial direction to press fit and release. the switching device Doo and the tapered projection and the tapered bore of complementary shape to are provided two Konami設, each piston of the respective switching device by a sheet discharge switching of pressurized fluid to said two cylinder chambers, the On one side through the conjugate Over path projections and to switch from a pressurized press fit engagement with the tapered bore to a pressurized圧勘case of the tapered projection and the tapered hole on the opposite side, Rutotomoni axial movement is driven, and the piston in one of the switching device The piston in the other switching device is driven simultaneously ,
A switching device for an electrical circuit for electric discharge machining, wherein a terminal portion for electrical lead connection is provided on the outer peripheral side surface of the conductor of the terminal material and each outer end of the piston rod. The switching device for each electrical circuit for electric discharge machining arranged in parallel in the upper and lower sides is such that a combined body composed of conductors of each terminal material is located at the center in the left-right direction via the combined body of one switching device. When the pair of pistons with piston rods facing each other moves leftward by driving, the driving is controlled so that the pair of pistons with piston rods of the other switching device simultaneously moves rightward. A switching device for a power supply circuit for electric discharge machining according to claim 1 . One input line P3 output from a plurality of power supply apparatuses having different types of processing power supply circuits by a coaxial cable or a shield line is connected to the P3 terminal of one piston rod of one switching apparatus, and the other input line P4 is connected to the P4 terminal of the conductor of the terminal material of the other switching device,
The output line P3 on one worktable side of the machining unit inter-electrode line is connected to the P3W terminal of the conductor of the terminal material of the one switching device, and the output line P4 on the other wire electrode side is connected to the other switching device. Connected to the P4G terminal of the other piston rod,
Further, the input of the primary winding of the high-frequency coupling transformer of the ring core that converts the output DC pulse of the high-frequency pulse generation circuit output from the output lines P3 and P4 of the power supply device into an AC pulse is connected to the P3 terminal and the other on the one of the piston rod terminal of the switching device, also, the output of the secondary winding to claim 2, characterized in that formed by connecting to the terminal of the other piston rod of the P4G terminal and one switching device The switching apparatus of the power supply circuit for electrical discharge machining of description.

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