WO2013154149A1

WO2013154149A1 - Electric-discharge machining switching apparatus

Info

Publication number: WO2013154149A1
Application number: PCT/JP2013/060902
Authority: WO
Inventors: 保坂昭夫
Original assignee: 株式会社ソディック
Priority date: 2012-04-11
Filing date: 2013-04-11
Publication date: 2013-10-17
Also published as: JP5291220B1; CN104023892A; JP2013215855A; CN104023892B

Abstract

A switching apparatus, the purpose of which is to provide an electric-discharge machining switching apparatus that can keep down problems such as poor connections arising as a result of wear of parts due to reciprocating motion of moving parts or the like, is equipped with a housing, a first conductor (13), a second conductor (14), a third conductor (15), and a driving means (17). The housing forms tightly-sealed space, and the third conductor can move back and forth within the housing. The first conductor comprises a connection face (13A) that is parallel to the movement direction of the third conductor. The second conductor comprises a connection face (14A) that forms, with the connection face of the first conductor, a wedge-shaped space the size of which becomes smaller in the forward direction. The third conductor comes in contact, by moving forward, with both the connection face of the first conductor and the connection face of the second conductor within the wedge-shaped space, and electrically connects the first conductor and the second conductor.

Description

EDM switch device

The present invention relates to an electric discharge machining apparatus for machining a workpiece by supplying a current pulse from a power source to a machining gap formed between a tool electrode and the workpiece. In particular, the present invention relates to an electrical discharge machining switch device provided between a power source and a machining gap.

Conventionally, an electric discharge machining apparatus is known as a machine tool for machining a workpiece into a desired shape by repeatedly generating an electric discharge in a machining gap by applying a voltage pulse. During machining, the machining gap is filled with machining fluid. The working fluid is a dielectric fluid based on water or oil. Since it is difficult to install an electric discharge machining power supply (hereinafter referred to as “power supply”) in the electric discharge machine, the electric discharge machine is installed in a power supply unit attached to the electric discharge machine. . If the distance between the power supply and the machining gap is increased, the current pulse waveform will be distorted and the loss of electrical energy will increase, so the power supply unit and this machine will be as close as possible. Connected. In Patent Document 1, a circuit switching device using an electric discharge machining switch is arranged as close to the machining gap as possible, so that the waveform rises and falls sharply and has a current pulse showing a high peak value. A wire electric discharge machining apparatus capable of supplying a high-frequency AC voltage between tool electrodes is disclosed.

In general, an electrical discharge machining device switches several types of circuits with a circuit switching device using an electrical discharge machining switch according to the machining mode, required machining speed, machining surface roughness, or machining shape accuracy. By using them, a machining current pulse having a required waveform is supplied between both electrodes of the tool electrode and the workpiece to obtain a desired machining result. Furthermore, for reasons such as effective cooling of the machining gap and removal of machining debris, electric discharge machining is often performed by placing the workpiece in the machining tank in the machining liquid. For example, Patent Document 2 discloses a movable body that can reciprocate a piston in a cylinder chamber provided in a waterproof storage body, and has a first contact on one end side and a second contact on the other end side. There has been proposed a switch device for electric discharge machining configured to switch between conduction and non-conduction of a first terminal and a second terminal using a conductive movable body. In the switch device described in Patent Document 2, the first contact is slidably provided on the one end side of the movable body with the first contact that is electrically connected to the first terminal, and the first contact and the first terminal are provided. Is always maintained during the reciprocating motion of the movable body. Then, a second contact configured in a flat surface shape is provided on the other end side of the movable band, and when the movable body moves to the other end side in accordance with the reciprocating motion, the second contact is configured in a flat surface shape of the second terminal. It is comprised so that the contacted contact may be conducted.

Patent Document 3 discloses a circuit switching device using an electrical discharge machining switch device including first, second, and third terminals. The first terminal is disposed in the center of the cylinder chamber. The second terminal is attached to one piston that can reciprocate in the cylinder chamber. The third terminal is attached to another piston that can reciprocate in the cylinder chamber. Switching between conduction and non-conduction between the first terminal and the second terminal or between the first terminal and the third terminal is performed by the reciprocating motion of the two pistons. The two pistons are slidably provided through the housing. The contact portions of the two pistons have a concave shape that becomes wider as approaching the first terminal. The two contact points of the first terminal are each convex. The contact of each piston can be fitted to the respective contact of the first terminal.

US Pat. No. 5,750,951 US Pat. No. 6,291,791 Japanese Patent Publication No. 2005-279780

However, in order to perform electrical discharge machining by installing it in the machining fluid, an electrical discharge machining switch that can prevent problems such as poor connection caused by wear of parts due to reciprocating movement of the movable part, etc. while ensuring waterproofness. Realization is required. In order to realize both of these requirements, in Patent Documents 1 and 3 described above, since the movable body slides through the housing, the waterproof property is improved so that the processing liquid is not immersed in the sliding portion of the housing. In Patent Document 2, since the sliding portion has a relatively wide area, it is further required to suppress problems such as wear of parts due to the reciprocating motion of the movable portion.

The present invention has been made in view of such problems. An object of the present invention is to provide a switch device for electric discharge machining that can suppress problems such as poor connection caused by wear of parts due to reciprocating motion of a movable part, etc. while ensuring waterproofness.

An electrical discharge machining switch device according to the present invention includes a housing that forms a sealed space, a moving body that moves back and forth in the sealed space, a first terminal that can be electrically connected to the outside of the housing, and an interior of the sealed space. A first conductor located in front of the moving body and having a connection surface parallel to a moving direction of the moving body; a second terminal electrically connectable to the outside of the housing; and the inside of the sealed space A wedge-shaped space that is located in front of the moving body, is inclined at a predetermined angle with respect to the moving direction of the moving body, and decreases in size toward the front of the moving body is formed between the connecting surface of the first conductors. A second conductor having a connection surface, and moved forward and backward by the moving body, and in contact with both the connection surface of the first conductor and the connection surface of the second conductor in the wedge-shaped space by forward movement. The first conductor and the first conductor And electrically connecting the first conductor and the second conductor away from at least one of the connection surface of the first conductor and the connection surface of the second conductor by rearward movement. A third conductor to be released and drive means for moving the moving body back and forth in the sealed space are provided.

The housing may have any configuration as long as it forms a sealed space. For example, the housing may be composed of one component or a plurality of components, and a part of the housing may be composed of the first conductor or the first conductor. You may be comprised from 2 conductors.

The first conductor has a first terminal that can be electrically connected to the outside of the housing, and a connection surface that is positioned in front of the moving body inside the sealed space and parallel to the moving direction of the moving body. Any material, structure, and component configuration can be applied as long as the first terminal and the connection surface are electrically connected.

The second conductor is positioned in front of the moving body inside the sealed space and a second terminal that can be electrically connected to the outside of the housing, and is inclined at a predetermined angle with respect to the moving direction of the moving body. Any connecting surface that forms a wedge-shaped space that decreases in size toward the front of the moving body and is electrically connected to the second terminal and the connecting surface. The material, structure, and component configuration can be applied.

The third conductor contacts both the connection surface of the first conductor and the connection surface of the second conductor in the wedge-shaped space by moving forward, and the first conductor and the second conductor Are electrically connected to each other and separated from at least one of the connection surface of the first conductor and the connection surface of the second conductor by rearward movement to release the electrical connection between the first conductor and the second conductor. Any material, structure, and component configuration can be applied.

Further, the driving means may be any driving means as long as the movable body can be moved back and forth. For example, the sealed space is made into a cylinder shape, and the moving body is configured as a piston that can move within the cylinder, and the piston moves by changing the pressure in the cylinder by supplying or sucking air to the cylinder. It may be configured by an air pump or the like.

In the switch device for electric discharge machining according to the present invention, the connection surface of the first conductor is an outer surface of the columnar body, and the connection surface of the second conductor is located outside the columnar body. The third conductor is disposed at a position surrounding the outside of the columnar body, and is supported by a rear end portion and has a cantilever structure parallel to the moving direction. A plurality of claws, and each of the plurality of conductive claws includes a front conductive portion having an inner surface parallel to the connection surface of the first conductor and an outer surface parallel to the connection surface of the second conductor on the front side, The plurality of conductive claws are deformed to the connection surface side of the first conductor by pressing the outer surface of the front conductive portion by the connection surface of the second conductor according to the forward movement of the movable body. The inner surface of the front conductive portion presses the connection surface of the first conductor, and the movable body In accordance with the backward movement, one of the connection surface of the first conductor and the inner surface of the front conductive portion and the connection surface of the second conductor and the outer surface of the front conductive portion are separated to release the electrical contact. It is preferable to do.

As described above, in the case where the connection surface of the first conductor is formed by the outer surface of the columnar body, since there is practically no restriction on the positional accuracy in the circumferential direction, the connection of the first conductor is performed. The surface is preferably an outer surface of a cylinder having an axis parallel to the moving direction of the moving body.

Further, the plurality of conductive claws of the third conductor can be disposed at any position as long as they surround the outer surface of the columnar body. For example, the plurality of conductive claws are surrounded at equal intervals around the outer side of the columnar body. It is preferable that the number of the plurality of conductive claws be four or more. The plurality of conductive claws of the third conductor can be applied with any material, structure, and component configuration as long as the inner side surface and the outer side surface of the front conductive portion are electrically connected. It need not be composed of materials.

Further, the plurality of conductive claws are configured such that each inner surface of the plurality of conductive claws grips the connection surface of the first conductor from the periphery according to deformation of the plurality of conductive claws, and the first conductive It is preferable that the body is supported by the housing so that the body can move forward as the moving body moves forward by gripping the connection surface of the first conductor.

In this case, the plurality of conductive claws are each deformed toward the connection surface side of the first conductor by pressing the outer surface of the front conductive portion, and the plurality of conductive claws according to the deformation of the plurality of conductive claws. As long as each inner surface can press and hold the connection surface of the first conductor from the periphery, the material, shape, structure, and number of conductive claws of the conductive claws may be arbitrarily selected.

Further, the first conductor may be supported by the housing by an arbitrary method as long as the connection surface of the first conductor is gripped so that the first conductor can move forward as the moving body moves forward.

In the electric discharge machining switch device of the present invention, it is preferable that the predetermined angle has an inclination of 10 degrees or more and 20 degrees or less with respect to the moving direction.

In the electric discharge machining switch device according to the present invention, it is preferable that the first conductor and the second conductor are made of a material that is less likely to be worn than the third conductor.

The switch device for electric discharge machining according to the present invention includes a housing that forms a sealed space, a moving body that moves back and forth in the sealed space, a first terminal that can be electrically connected to the outside of the housing, and a moving body that is located inside the sealed space. A first conductor having a connection surface parallel to the moving direction of the moving body, a second terminal electrically connectable to the outside of the housing, and positioned in front of the moving body inside the sealed space; A second conductor having a connecting surface that forms a wedge-shaped space that is inclined at a predetermined angle with respect to the moving direction of the moving body and decreases in size toward the front of the moving body between the connecting surface of the first conductor, The first conductor and the second conductor are electrically connected to each other in contact with both the connection surface of the first conductor and the connection surface of the second conductor in the wedge-shaped space by the forward movement, which is moved back and forth by the moving body. Along with the backward movement, the first conductor A third conductor that is spaced apart from at least one of the connecting surface and the connection surface of the second conductor to release the electrical connection between the first conductor and the second conductor, and a drive unit that moves the moving body back and forth within the sealed space And. As a result, the third conductor is interposed in the wedge-shaped space between the first conductor and the second conductor so that the first conductor and the second conductor are in a conductive state. All of the connection surface, the connection surface of the second conductor, and the portion of the third conductor that contacts these are arranged in the sealed space, and the electrical connection is turned on and off by moving back and forth in the sealed space of the third conductor. As a result, the waterproof property can be ensured, and even if any of the first conductor, the second conductor, and the third conductor is worn, the third conductor is the first and second conductors. By increasing the amount of movement of the third conductor to a position deep in the wedge-shaped space where the bodies can be electrically connected, problems such as poor connection due to wear of any of the first to third conductors can be suppressed.

In the electrical discharge machining switch device, the connection surface of the first conductor is the outer surface of the columnar body, and the connection surface of the second conductor is opposed to the connection surface of the first conductor positioned outside the columnar body. The third conductor has a plurality of conductive claws having a cantilever structure parallel to the moving direction supported by the rear end at a position surrounding the outside of the columnar body, and each of the plurality of conductive claws is a front Provided with a front conductive portion having an inner surface parallel to the connection surface of the first conductor and an outer surface parallel to the connection surface of the second conductor, and the plurality of conductive claws according to the forward movement of the movable body The outer surface of the front conductive portion is pressed to be deformed to the connection surface side of the first conductor so that the inner surface of the front conductive portion is in contact with the connection surface of the first conductor and the connection surface of the second conductor is forward. The outer surface of the conductive portion comes into contact, and the connection surface of the first conductor and the inner surface of the front conductive portion according to the backward movement of the moving body, When either one of the connection surface of the two conductors and the outer surface of the front conductive portion are separated to release the electrical contact, the conductive claw is pressed against the connection surface of the second conductor and deformed by the front conductor. The portion can suitably enter the depth of the wedge-shaped space. Therefore, the inner and outer surfaces of the front conductive portion can be in good contact with both connection surfaces, and the connection surface of the first conductor and the connection surface of the second conductor can be electrically connected.

Further, in the switch device for electric discharge machining, the plurality of conductive claws are configured such that each inner surface of the plurality of conductive claws grips the connection surface of the first conductor from the periphery according to the deformation of the plurality of conductive claws. When the conductor is supported by the housing so that the connection surface of the first conductor is gripped by the plurality of conductive claws so that the conductive claws are moved forward, the first conductor is connected. The front conductive portion can enter the wedge-shaped space up to a position where the frictional force is balanced with respect to the connection surfaces of both the surface and the connection surface of the second conductor. Therefore, the inner and outer surfaces of the front conductive portion can be in good contact with both connection surfaces, and the connection surface of the first conductor and the connection surface of the second conductor can be electrically connected.

It is a figure which shows the electric discharge machining apparatus which concerns on one embodiment of this invention. It is sectional drawing of the switch apparatus for electric discharge machining of FIG. It is a principal part enlarged view of the switch apparatus for electrical discharge machining of FIG. FIG. 3 is a perspective sectional view of the electric discharge machining switch device of FIG. 2. FIG. 3 is a perspective view of the electric discharge machining switch device of FIG. 2.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of an electric discharge machine to which the switch apparatus for electric discharge machining of the present invention can be applied. The electric discharge machine is a wire electric discharge machine that cuts the workpiece 3 like a yarn saw by the wire electrode 2 that is a tool electrode.

As shown in FIG. 1, the electric discharge machine has a pair of upper and lower wire guide assemblies 4 that support the wire electrode 2. A wire guide, a nozzle 41, and a power feeding body 42 are incorporated in the wire guide assembly 4. The nozzle 41 is provided for injecting a machining liquid into the machining gap. The power feeder 42 is in contact with the traveling wire electrode 2. During processing, power from a power source (not shown) is supplied to the wire electrode 2 via the power supply body 42. The work 3 is installed on the metal part of the work stand 6 in the processing tank 5. The processing tank 5 is filled with a processing liquid. During machining, power from the power source is supplied to the work 3 via the metal part of the work stand 6.

Further, the electric discharge machine includes a circuit switching device 7 for switching a circuit as needed and applying a high frequency voltage. The circuit switching device 7 includes a transformer 8, first to fourth switch devices 1A to 1D, a driving device 17, and a control device 18. The transformer 8 includes a ferrite ring core 81, a primary winding 82 and a secondary winding 83. The control device 18 may be a numerical control device. The switch devices 1A to 1D are provided between the power source and the machining gap, and the electrical discharge machining switch device of the present invention is applied to each of the switch devices 1A to 1D. The switch devices 1A to 1D and the transformer 8 are housed in a box 9 to constitute one circuit switching unit. The circuit switching unit is attached to the processing tank 5. The transformer 8 is provided to convert a high-frequency DC pulse supplied from a power source into a high-frequency AC pulse. When a machining fluid based on water is used, electric discharge machining using high-frequency alternating current pulses can improve the surface roughness of the workpiece 3 while preventing electrolytic corrosion of the workpiece 3.

The control device 18 outputs a switching signal to the drive device 17 in accordance with the NC program or in response to an operator input. The drive device 17 is configured to selectively send air of a predetermined pressure to each of the switch devices 1A to 1D according to the switching signal. The driving device 17 is a supply source of pressurized air that operates each moving body 12 of the switch devices 1A to 1D.

Both terminals shown on the right side in FIG. 1 are connected to a power source. The first switch device 1 A is provided between lines connecting the positive electrode of the power source and the work 3. The second switch device 1B is provided between lines connecting the negative electrode of the power source and the wire electrode 2. A first node 21 is disposed between the positive electrode of the power source and the first switch device 1A, and a second node 22 is disposed between the negative electrode of the power source and the second switch device 1A. . The third node 23 is disposed between the first switch device 1 A and the work 3, and the fourth node 24 is disposed between the second switch device 1 A and the wire electrode 2. The third switch device 1 C is provided on a line where the first node 21 is connected to the second node 22 via the primary winding 82. The fourth switch device 1 D is provided on a line where the third node 23 is connected to the fourth node 24 via the secondary winding 83.

The transformer 8 is selectively connected to a pulse supply circuit (not shown) in the power supply unit by combining the first to

fourth switch devices

1A, 1B, 1C, and 1D. In other words, the first to

fourth switch devices

1A, 1B, 1C, and 1D switch between a pulse supply circuit that includes the transformer 8 and a pulse supply circuit that does not include the transformer 8. In rough machining, the transformer 8 is not added to the pulse supply circuit by turning on the

switch devices

1A and 1B and turning off the

switch devices

1C and 1D. In the finishing process, the transformer 8 is connected to the high-frequency pulse supply circuit by turning off the

switch devices

1A and 1B and turning on the

switch devices

1C and 1D.

In order to apply a high-frequency voltage pulse to the machining gap while maintaining a high peak waveform while suppressing energy loss, the first to

fourth switch devices

1A, 1B, 1C, 1D and the transformer 8 are connected to the machining gap. It is necessary to install in the vicinity. Further, the number of switch devices is not limited to the present embodiment as long as it has a function of switching the pulse supply circuit.

As shown in FIGS. 2 to 5, the switch device 1 A includes a housing, a moving body 12, a first conductor 13, a second conductor 14, a third conductor 15, and a driving device 17. ing. The housing includes a storage body 11, a second conductor 14, a first conductor 13, and a support portion 16, and forms a cylinder chamber 11A that is a sealed space. The storage body 11 is a rectangular parallelepiped with one surface released. The second conductor 14 is attached to the storage body 11 so as to cover the release surface of the storage body 11. The second conductor 14 has a through hole in the center that decreases in size as it goes forward of the moving body 12. The moving body 12 is housed in the housing and can move back and forth in the sealed space. The first conductor 13 has a columnar body portion 13B having a substantially cylindrical body shape. The first conductor 13 has a first terminal T that can be electrically connected to the outside of the housing. The first conductor 13 further has a connection surface 13A located in front of the moving body 12 and parallel to the moving direction P of the moving body 12 in the sealed space 11A. The support portion 16 supports the first conductor 13 in an insulated state with respect to the second conductor 14 so that the columnar body portion 13B is disposed at the center of the through hole of the second conductor 14.

The second conductor 14 has a second terminal C (not shown) that can be electrically connected to the outside of the housing. The second conductor 14 further has a connection surface 14 A that is positioned in front of the moving body 12 in the sealed space 11 A and is inclined at a predetermined angle with respect to the moving direction P of the moving body 12. The connection surface 14A forms a wedge-shaped space 11B that decreases in size as it goes forward of the moving body 12 between the connection surface 13A of the first conductor. The third conductor 15 is attached to the moving body 12 and can move back and forth with the moving body 12. The third conductor 15 moves forward to contact both the connection surface 13A of the first conductor and the connection surface 14A of the second conductor in the wedge-shaped space 11B to electrically connect the first conductor and the second conductor. To do. The third conductor 15 is separated from at least one of the connection surface 13A of the first conductor and the connection surface 14A of the second conductor by rearward movement, and the electrical connection between the first conductor 13 and the second conductor 14 is released. To do. The driving device 17 (driving means) moves the moving body 12 back and forth within the sealed space.

The first terminal T is located in front of the moving body 12 and is exposed to the outside of the housing. The first conductor 13 includes a columnar body portion 13B that extends inward of the cylinder chamber 11A at the rear end. The outer peripheral surface of the columnar body portion 13B is a connection surface 13A of the first conductor.

A recess 14C is formed in the second conductor 14 outside the housing, and the second terminal C is provided in the recess 14C. The second conductor 14 is located in front of the moving body 12 inside the sealed space. The inner surface of the through hole of the second conductor 14 is a connection surface 14 A of the second conductor 14. The columnar body portion 13B of the first conductor 13 is supported so as to be positioned at the center of the through hole of the second conductor 14. Therefore, the connection surface 13A of the first conductor 13 faces the connection surface 14A of the second conductor 14, and a wedge-shaped space 11B is formed between the connection surface 13A and the connection surface 14A.

The connection surface 13A of the first conductor 13 and the connection surface 14A of the second conductor 14 form a wedge-shaped space 11B that decreases in size toward the front. Therefore, even if any of the first conductor 13, the second conductor 14, and the third conductor 15 is worn, a connection failure due to wear is overcome by an increase in the amount of movement of the third conductor 15.

As shown in FIG. 3, the connection surface 14 A of the second conductor 14 is inclined by a predetermined angle θ so that the size decreases as it goes forward with respect to the moving direction P of the moving body 12. Therefore, when the third conductor 15 comes into contact with the connection surface 14A of the second conductor 14 in accordance with the forward movement of the moving body 12, the force that moves the moving body 12 forwards the third conductor 15 to the second conductive. It works in the direction of pressing against the connection surface 14A of the body 14. As a result, a good electrical connection is realized between the connection surface 14A of the second conductor 14 and the outer surface 15B of the third conductor 15. The angle θ is within a range in which the friction force between the connecting surface 14A of the second conductor 14 and the surface of the third conductor 15 and the friction coefficient can easily move the third conductor 15 back and forth in the wedge-shaped space. Set to be a value. For example, the inclination θ of the connection surface 14A of the second conductor 14 with respect to the moving direction P is preferably 10 degrees or more and 20 degrees or less. In the present embodiment, since the connection surface 14A of the second conductor 14 has an inclination of 15 degrees with respect to the moving direction P, the first conductor 13 is preferably moved forward and backward in the wedge-shaped space. The connection surface 13A and the connection surface 14A of the second conductor 14 can be electrically connected or disconnected.

In this embodiment, the connection distance between the 1st terminal T and the 2nd terminal C is short, and an electrical loss is smaller and preferable. In addition, since the front conductive portion 15D of the third conductor 15 moves in the wedge-shaped space whose size decreases toward the front as in the present embodiment, the third conductor 15 moves smoothly back and forth.

As shown in FIGS. 2 and 3, the third conductor 15 has a plurality of conductive claws 15 A extending in parallel with the moving direction P. The plurality of conductive claws 15 A are located in the cylinder chamber 11 A so as to surround the columnar body portion 13 B of the first conductor 13. The rear end portions of the plurality of conductive claws 15 A are supported by the moving body 12. Each of the plurality of conductive claws 15A includes a front conductive portion 15D on the front side. The front conductive portion 15D has an inner side surface 15C and an outer side surface 15B. The inner side surface 15 C is parallel to the connection surface 13 A of the first conductor 13. The outer side surface 15B is parallel to the connection surface 14A of the second conductor 14.

When the conductive claws 15 A move forward, the outer surface 15 B of each front conductive portion 15 D is pressed against the connection surface 14 A of the second conductor 14. Thus, as indicated by a broken line in FIG. 3, the conductive claws 15 A are deformed toward the connection surface 13 A side of the first conductor 13. As a result, the inner side surface 15C of the front conductive portion 15D is in contact with the connection surface 13A of the first conductor 13, and the outer side surface 15B of the front conductive portion 15D is in contact with the connection surface 14A of the second conductor 14. 3, when the conductive claw 15A moves rearward, at least one of the inner side surface 15C and the outer side surface 15B of the front conductive portion 15D is separated from the first conductor 13. As a result, the electrical connection between the first conductor 13 and the second conductor 14 is released.

In the present embodiment, the conductive claw 15A has a cantilever structure parallel to the moving direction P connected to the moving body 12 at the rear end, and the first conductive body 13 and the front conductive section 15 are slightly separated from each other. Arranged (d> 0). The conductive claws 15 A can be elastically deformed toward the connection surface 13 A side of the first conductor 13 in accordance with the forward movement of the moving body 12. For this reason, when the front conductive portion 15D is pressed by the connection surface 14A of the second conductor 14 and displaced inward, the front conductive portion 15D can suitably enter the depth of the wedge-shaped space. As a result, the inner and

outer surfaces

15C and 15B of the front conductive portion 15D can make good contact with both the connection surfaces 13A and 14A. Further, according to the rearward movement of the moving body 12, the conductive claw 15 A separates the connection surface 13 A of the first conductor 13 and the inner side surface 15 C of the front conductive portion 15 D only by the elastic deformation restoring force, thereby releasing the electrical contact. can do. Further, as the third conductor 15 advances deeper into the wedge-shaped space, the force that moves the moving body 12 forward is the reaction force of the connection surface 14A of the second conductor 14 and the front conductive portion 15 is connected to the first conductor 13. It works more greatly in the direction of pressing against the surface 13A. Therefore, the connection surface 14A of the second conductor 14 and the third conductor 15 can be electrically connected more satisfactorily.

In the present embodiment, the distance d between the connection surface 13A of the first conductor 13 and the inner surface 15C of the plurality of front conductive portions 15D is a small value of about 0.2 mm or less. In this case, the inner side surface 15C can be brought into contact with the connection surface 13A only by deforming the conductive claw 15A small, without increasing the force for moving the moving body 12 forward.

The distance d between the first conductor 13 and the front conductive portion 15D may be zero. In this case, the front conductive portion 15D slides while maintaining electrical connection with the connection surface 13A of the first conductor 13. When the outer surface 15B of the front conductive portion 15D comes into contact with the connection surface 14A of the second conductor 14 in accordance with the forward movement of the moving body 12, the electrical connection between the first and

second conductors

13 and 14 is turned on. When the outer surface 15B of the front conductive portion 15D is not in contact with the connection surface 14A of the second conductor 14 in accordance with the rearward movement of the moving body 12, the electrical connection between the first and

second conductors

13 and 14 is turned off. . When the plurality of conductive claws 15A slide on the surface of the columnar body portion 13B, the back and forth movement of the third conductor 15 is stabilized. Since each inner side surface 15C of the plurality of front conductive portions 15D is always in conduction with the connection surface 13A of the first conductor 13, the outer side surface 15B of the front conductive portion 15D is in contact with the connection surface 14A of the second conductor 14. Only by this, the electrical connection of the switch device 1A can be made immediately. Also at this time, it is preferable that the conductive claws 15 A are configured to be slightly deformable on the connection surface 13 A side of the first conductor 13.

The conductive claws 15 A can be slightly deformed toward the connection surface 13 A side of the first conductor 13. Therefore, the force by which the front conductive portion 15D is pressed by the connection surface 14A of the second conductor 14 is preferably converted into the force by which the inner side surface 15C of the front conductive portion 15D presses the connection surface 13A of the first conductor 13. The As a result, the contact pressure between the connection surface 13A of the first conductor 13 and the inner side surface 15C of the front conductive portion 15D becomes larger.

In the present embodiment, a plurality of conductive claws 15A are provided at equal intervals. In addition, the front conductive portion 15D has a wide surface in contact with the connection surface 13A and the connection surface 14A. The contact area is large and the loss of electrical energy is suppressed. Further, the plurality of conductive claws 15A are arranged so as to surround the connection surface 13A that is the surface of the columnar body of the first conductor 13 from a plurality of directions, and the first conductor 13 of the first conductor 13 according to the forward movement of the movable body 12 It deform | transforms so that it may press toward 13 A of connection surfaces which are the surfaces of a columnar body. For this reason, since the conductive claws 15A are pressed against the first conductor 13 from a plurality of directions by moving the moving body 12 forward, it is difficult for a biased load to be applied to the first conductor 13, and the first conductor 13 is placed inside the first conductor 13. The inner side surfaces 15C of the third conductor 15 can be brought into firm contact with each other.

In the present embodiment, the inner surface 15C of the third conductor 15 is parallel to the connection surface 13A of the first conductor 13, and the outer surface 15B of the third conductor 15 is the connection surface 14A of the second conductor 14. Parallel to Therefore, the first conductor 13 and the third conductor 15 can be in firm contact with each other, so that a good electrical connection state is realized.

The shape and material of the conductive claw 15A are not limited as long as the conductive claw 15A can be elastically deformed toward the connection surface 13A side of the first conductor 13 in accordance with the forward movement. For example, four or more conductive claws 15A can be provided. In this case, it is easy to ensure elasticity that deforms the conductive claws 15A inward according to the forward movement of the moving body 12, and the conductive claws 15A are directed to the first conductor 13 from a plurality of directions toward the inside of the first conductor 13. Each inner side surface 13B of 13 can be hold | maintained firmly.

Further, the present invention is not limited to this embodiment, and the third conductor 15 can have any shape that can be inserted into the wedge-shaped space 11B. Further, the connection surface 13A of the first conductor 13 and the portion of the third conductor 15 that contacts the connection surface 14A of the second conductor 14 may have any shape. In this embodiment, the moving body 12 and the conductive claw 15A are integrally formed. However, these may be manufactured and assembled as a plurality of parts.

As shown in FIG. 2, the moving body 12 includes a piston 12A and a piston ring 12B. The piston ring 12B is provided on the outer periphery of the piston 12A in order to prevent air leakage.

Holes

11C and 11D are formed in the wall of the storage body 11 constituting a part of the housing. A driving device 17 (driving means) that moves the piston 12A back and forth is connected to the

holes

11C and 11D. The drive device 17 includes an air pump 17A, a plurality of valves 17B, and a hose 17C. The driving device 17 slides the moving body 12 in the cylinder chamber 11A by the force of air. The drive device 17 operates the air pump 17A and the plurality of valves 17B in response to a switching signal from the control device 18. When air is supplied to the hole 11D, the air in the cylinder chamber 11A is discharged from the hole 11C. When air is supplied to the hole 11C, the air in the cylinder chamber 11A is discharged from the hole 11D.

Since the moving body 12 is driven by air pressure, the switch device is preferable because it has a relatively simple structure and has a low risk of failure. Since the driving device 17 drives the moving body 12 by the pressure of air, the moving body 12 stops at a position where the third conductor 15 contacts the first conductor 13 and the second conductor 14. Therefore, even when any one of the first, second, and third conductors is worn, no special control is required for increasing the moving amount of the moving body 12. An insulating working fluid may be used for the driving device 17 instead of air. A drive unit having an arbitrary configuration capable of moving the moving body 12 back and forth within the sealed space is applicable.

As shown in FIG. 2, the housing is constituted by a storage body 11, a first conductor 13, a second conductor 14, and a support portion 16. The housing is assembled so that there are no gaps between the elements. Since a part of the housing is composed of the first conductor 13 and the second conductor 14, the structure of the switch device is simplified and preferable.

According to the present embodiment, all of the connection surface 13A, the connection surface 14A, the inner side surface 15C, and the outer side surface 15B are disposed in the sealed space. Since the electrical connection is turned on and off by moving the third conductor 15 back and forth within the sealed space, waterproofing can be ensured, and the occurrence of problems due to the penetration of liquid from the outside can be suitably prevented.

When the plurality of conductive claws 15 A grip the first conductor 13 by their deformation, the first conductor 13 is supported by the housing so as to move forward as the moving body 12 moves forward. In this case, the front conductive portion 15D can enter the wedge-shaped space up to a position where the frictional force is balanced with respect to the connection surfaces of both the connection surface 13A of the first conductor 13 and the connection surface 14A of the second conductor 14. Therefore, the contact pressure of the front conductive portion 15D increases with respect to either or both of the connection surfaces 13A and 14A. As a result, electrical energy loss can be reduced. Although the first conductor 13 slides with respect to the housing, since the sliding distance is very small, the waterproof property between the housing and the first conductor 13 can be kept good.

The first conductor 13 is a cylindrical body and has a flange portion at the rear end. A through hole having a diameter substantially the same as the diameter of the first conductor 13 is formed in the housing (support portion 16). The first conductor 13 is inserted through the through hole so that the flange portion of the first conductor 13 is located inside the housing. An O-ring is provided between the through hole and the flange portion. As the moving body 12 moves forward, the O-ring is pressed against the flange portion and elastically deforms slightly. The first conductor 13 can move forward by the amount of deformation of the O-ring.

In the embodiment, the first conductor 13 and the second conductor 14 are preferably made of a material that is less likely to wear than the third conductor 15. In this case, the third conductor 15 is more worn out than the first conductor 13 and the second conductor 14. However, since the size of the wedge-shaped space formed by the first conductor 13 and the second conductor 14 is relatively maintained, a reliable electrical connection is maintained by increasing the amount of movement of the third conductor 15.

The switch device of the present invention can be applied to other electric discharge machining circuits that are desirably provided as close to the machining gap as possible. For example, the switch device of the present invention can be used to switch between an electrical discharge machining circuit for rough machining including a low inductance wire such as a coaxial cable and an electrical discharge machining circuit for finishing machining including a low capacitance wire. is there.

C second terminal T first terminal 1A-1D switching device (switching device for electric discharge machining)
2 Wire electrode 3 Work 4 Wire guide assembly 5 Processing tank 6 Work stand 7 Circuit switching device 8 Transformer 9 Box 11 Storage body 11A Cylinder chamber (sealed space)
11B Wedge-shaped

space

11C, 11D Hole 12A Piston 12B Piston ring 13 First conductor 13A Connection surface 13B of the first conductor Columnar body portion 14 Second conductor 14A Connection surface 14C of the second conductor Recess 15 Third conductor 15A Conductive claw 15B Outer side surface 15C Inner side surface 15D Front conductive portion 16 Support portion 17 Drive device 17A Air pump 17B Valve 17C Hose 18 Control device 21-24 Node 41 Nozzle 42 Feeder 81 Ferrite ring core 82 Primary winding 83 Secondary winding

Claims

A housing forming a sealed space;
A moving body that moves back and forth in the sealed space;
A first terminal that can be electrically connected to the outside of the housing; a first conductor having a connection surface that is positioned in front of the moving body inside the sealed space and parallel to a moving direction of the moving body;
A second terminal that can be electrically connected to the outside of the housing; and located in front of the moving body inside the sealed space, inclined at a predetermined angle with respect to a moving direction of the moving body, and a connection surface of the first conductor A second conductor having a connection surface that forms a wedge-shaped space that decreases in size toward the front of the movable body,
The first conductor and the second conductor are brought into contact with both the connection surface of the first conductor and the connection surface of the second conductor in the wedge-shaped space by the forward movement and are moved back and forth by the movable body. Are electrically separated from each other and separated from at least one of the connection surface of the first conductor and the connection surface of the second conductor by rearward movement, and the electrical connection between the first conductor and the second conductor is released. A third conductor;
A switch device for electric discharge machining comprising drive means for moving the movable body back and forth in the sealed space.
The connection surface of the first conductor is an outer surface of the columnar body,
The connection surface of the second conductor is a surface facing the connection surface of the first conductor located outside the columnar body;
The third conductor is disposed at a position surrounding the outside of the columnar body and has a plurality of conductive claws having a cantilever structure parallel to the moving direction and supported by a rear end portion, and the plurality of conductive claws Each includes a front conductive portion having an inner surface parallel to the connection surface of the first conductor and an outer surface parallel to the connection surface of the second conductor, and the plurality of conductive claws are arranged on the movable body. In response to the forward movement, the outer surface of the front conductive portion is pressed by the connection surface of the second conductor to be deformed to the connection surface side of the first conductor, and the connection surface of the first conductor is The inner side surface of the front conductive portion is pressed, and the connection surface of the first conductor, the inner side surface of the front conductive portion, the connection surface of the second conductor, and the front conductive portion of the front conductive portion according to the rearward movement of the moving body. 2. Any one of the outer surfaces is separated to release electrical contact. Placing the discharge machining switch device.
Each of the plurality of conductive claws grips the connection surface of the first conductor from the periphery according to deformation of the plurality of conductive claws,
The first conductor is supported by the housing so that the connection surface of the first conductor is held by the plurality of conductive claws so that the first conductive body can move forward with the forward movement of the plurality of conductive claws. The switch device for electric discharge machining according to claim 2.
The switch device for electric discharge machining according to any one of claims 1 to 3, wherein the predetermined angle is an inclination of 10 degrees or more and 20 degrees or less with respect to the moving direction.
5. The electrical discharge machining switch according to claim 1, wherein the first conductor and the second conductor are made of a material that is less likely to wear than the third conductor. 6. apparatus.