JP2001232520A - Power supply structure in wire electric discharge machine - Google Patents

Abstract

(57) [Summary] The present invention changes the sliding contact of a power supply with a wire electrode while the wire electrode is running,
Provided is a power supply structure in wire electric discharge machining that can significantly extend the life of a power supply. SOLUTION: A wire electrode 1 is provided during electric discharge machining of a workpiece.
The feeder 2 also rotates through the bevel gears 6 and 8, the spur gear 9, and the gear 11 formed on the feeder 2 as a rotation input unit, in accordance with the rotation of the roller 54 that guides and travels.
Since the hole center line CC of the through-hole 16 formed in the power supply 2 is deviated from the traveling path of the wire electrode 1, the sliding contact S between the wire electrode 1 and the power supply 2 is formed at the throat portion 17. Is a new sliding contact point which has been moved in the circumferential direction one after another on the inner peripheral surface of. The power supply 2 has no running flaws, has a long life, and has a stable power supply state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply structure in a wire electric discharge machine which supplies a current to a wire electrode to be processed by discharging a current between the workpiece and a workpiece in wire electric discharge machining.

[0002]

2. Description of the Related Art Conventionally, the supply of a machining current to a wire electrode used in a wire electric discharge machine has been performed by a power supply which is arranged on a frame of the machine and contacts a traveling wire electrode. FIG. 6 shows an example of a conventional wire electric discharge machine.
Is shown in As shown in FIG. 6, the wire electric discharge machine is equipped with an automatic wire supply device of an annealed dry supply type in which a wire electrode 1 that has been straightened by annealing (annealing) is passed through a start hole without using a water flow. Machine. The wire electrode 1 fed from the source bobbin 50 is supplied to a hole A such as a start hole or a machining slit of the workpiece W.
1. The vehicle travels while being guided by a wire electrode supply system including a tension roller 52, a brake roller 53, a direction change roller 54, a pull-out roller 55, and the like.

[0003] An upper wire head 56 and a lower wire head 57 are arranged on the frame of the processing machine above and below the workpiece W in order to accurately guide the wire electrode 1 to the workpiece W, respectively. The lower wire head 57 is supported by the tip of a lower arm attached to the head so as to hang down from above the processing tank, and has a direction change roller 54 therein. By guiding the wire electrode 1 by the upper wire head 56 and the lower wire head 57, the wire electrode 1 can be prevented from swaying between both heads.
It travels accurately with respect to the workpiece W. Lower wire head 57
In the downstream side, a drawing device such as a pair of drawing rollers 55 that pulls out the wire electrode 1 through the guide pipe and makes the wire electrode 1 in a tensioned state is attached to the outside of the processing tank.

The extracted wire electrode 1 is taken up on a take-up reel or discharged to a used wire reservoir (for example, a waste wire hopper) attached to a processing tank (not shown). The wire electrode 1 that has been subjected to the annealing process and has been straightened is inserted into the start hole of the workpiece W from its tip. An example of this type of automatic wire feeder is disclosed in Japanese Patent Application Laid-Open No. 2-145215.

[0005] The workpiece W includes upper wire heads 5 facing each other.
While being installed between the lower wire head 6 and the lower wire head 57, it is fixed to the processing tank by a suitable clamping means or supporting means. The electric discharge machining for the workpiece W is performed in a state where the workpiece is immersed in a machining fluid filled in a machining tank. The processing tank is driven by a cross slide composed of, for example, an X-axis table and a Y-axis table in accordance with the processing shape of the workpiece W in a plane defined by the X-axis and the Y-axis. The Y-axis table is driven in the Y-axis direction by a Y-axis servomotor on the bed base, and the X-axis table on which the processing tank is mounted is driven in the X-axis direction by the X-axis servomotor on the Y-axis table.

The wire electrode 1 used for the wire electric discharge machine has various sizes and materials of wire diameter.
Usually, a wire electrode made of brass and having a wire diameter φ of 0.2 (unit mm, the same applies hereinafter) is used. The slit width is obtained by adding a discharge gap generated between the wire electrode 1 and the workpiece W to the diameter of the used wire electrode 1, for example, 0.25 to 0.3.
The width is about mm. However, when a high precision of processing such as about 0.1 mm is required for the slit width and the radius of the minimum corner, a thin wire electrode having a diameter smaller than that is used.

The upper wire head 56 and the lower wire head 57
In order to supply a current for electric discharge machining to the traveling wire electrode 1, power supply terminals 58 and 59 slidably contacting the wire electrode 1 are provided. If the power supply terminals 58 and 59 have a structure in which the sliding contact with the wire electrode 1 cannot be changed, the contact portions of the power supply terminals 58 and 59 will gradually wear due to the sliding contact with the wire electrode 1, and the power supply terminals 58 and 59 will gradually wear. The sliding state between the wire electrode 1 and the wire electrode 1 changes, and the sliding resistance and the like of the wire electrode 1 increase, which may hinder electric discharge machining. In order to recover the wear of the contact portions of the power supply terminals 58 and 59, the mounting structure of the power supply terminals 58 and 59 to the frame is changed by changing the mounting position and the mounting posture.
8 and 59, the sliding contact with the wire electrode 1 can be changed.
8, 59 is a structure fixed so as not to move with respect to the frame.

According to the above-described power supply structure, during the electric discharge machining, the power supply terminals 58 and 59 are fixed, so that the power supply terminals 58 and 59 are consumed at a sliding contact with the wire electrode 1 after a certain period of use. Each time, it is necessary to move the contact position.
In addition, since the number of sliding contacts of the power supply terminals 58 and 59 is limited, if there is a flaw in several places of the power supply terminals 58 and 59, the power supply terminals 58 and 59 themselves need to be replaced.

[0009]

Therefore, it is possible to solve the above-mentioned problem by avoiding a situation in which the wire electrode extended and running during the electric discharge machining is kept in sliding contact with the power supply at one place. Is required.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a wire feed electrode and a wire electrode which are kept in sliding contact with each other even during electric discharge machining in which a wire electrode travels and electric discharge machining is performed on a workpiece. In order to increase the life of the power supply, the wire electrode discharge improves the electric discharge machining accuracy by stabilizing the power supply from the power supply to the wire electrode by preventing the power supply from being damaged. An object of the present invention is to provide a power supply structure in a processing machine.

The present invention is configured as follows to achieve the above object. That is, the present invention relates to an electric discharge machine which discharges a workpiece by causing a discharge phenomenon between the wire electrode and the workpiece while supplying power by contacting a feeder electrode with a traveling wire electrode. The present invention relates to a power supply structure in a wire electric discharge machine, wherein a sliding contact between the power supply electrode and the wire electrode is changed while the electrode is running.

According to the power supply structure of the wire electric discharge machine of the present invention, the sliding contact between the power supply and the wire electrode is changed while the wire electrode is running. Without being kept in contact, the power supply contacts the wire electrode one after another at new sliding contacts. Therefore, the power supply is not damaged due to wear caused by the wire electrodes continuing to slide at the same sliding contact point, and the electric power supply state is stabilized.

In the power supply structure of the wire electric discharge machine, the sliding contact of the power supply is changed in a direction intersecting the running direction of the wire electrode in the power supply. That is, since the sliding contact between the power supply and the wire electrode occurs in the traveling direction of the wire electrode, the sliding contact is slightly changed in a direction intersecting with the traveling direction of the wire electrode, and the sliding of the wire electrode is performed immediately before. The sliding contact of the supplied power supply is changed to a completely new sliding contact. Therefore, abrasion of the power supply such as scratching due to a limited wear location due to the fixed sliding contact point is avoided.

The feeder is a rotating body having a through-hole whose hole center line coincides with the axis of rotation of the feeder. When the feeder rotates, the wire electrode inserted into the through-hole slides. The sliding contact of the power supply is changed. That is, the power supply terminal is a rotating body having a rotation axis, and the power supply terminal is formed with a through-hole having a hole center line coincident with the rotation axis. The sliding contact with which the wire electrode inserted into the through hole slides is located on the inner surface of the through hole offset from the hole center line. Therefore, by rotating the power supply, the sliding contact of the power supply with the wire electrode moves in a direction intersecting the running direction of the wire electrode on the inner surface of the through-hole, and is successively changed to a new sliding contact. A throat portion is formed at the center of the through hole in the hole center line direction, and the sliding contact of the power supply is formed at the throat portion. That is, the wire electrode slides on the throat portion having the smallest cross-sectional area of the through hole.

The wire electric discharge machine has a wire guide for guiding the wire electrode to the workpiece, and the power supply is formed on a block electrode provided in the wire guide. A tubular portion rotatably fitted in the fitting hole and electrically connected to the block electrode; and a rotational force extending from the tubular portion to the outside of the fitting hole and rotating the power supply is introduced. A rotation input unit. According to the power feeder having such a structure, the power feeder is rotatably fitted into the fitting hole formed in the block electrode in the cylindrical portion, and fitted by the rotational force introduced into the rotary input portion. Rotate in the hole. For example, when the power supply electrode is in sliding contact with the fitting hole, it receives the supply of the processing current from the electrically connected block electrode and supplies power to the wire electrode in sliding contact with the inside of the cylindrical portion. In addition, in consideration of the stability of the power supply, it is preferable that the tubular portion is disposed at the lower portion, and the rotation input portion is provided at an extending portion extending above the fitting hole from the tubular portion.

[0016] The rotation input section of the power supply is rotated by meshing with a gear to which torque is input by meshing of a gear, a pulley to which torque is input via a wound belt, or a worm. It is configured as a worm wheel to which force is input. The rotational force of the drive source is input via a suitable transmission mechanism to a rotation input unit of a power supply configured as a gear, a pulley, or a worm wheel, and rotates the power supply.

A rotation force is input to the rotation input section of the power supply via a transmission mechanism from a rotation shaft that rotates a roller disposed in a wire electric discharge machine for guiding and running the wire electrode. . In a wire electric discharge machine, a roller is disposed near a power supply for guiding and running a wire electrode. Therefore, it is preferable that the rotational force for rotating the power supply be taken in from the rotating shaft for rotating the roller via the transmission mechanism.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power supply structure in a wire electric discharge machine according to the present invention will be described with reference to FIGS. FIG. 1 is a partial sectional side view showing an outline of an embodiment of a power supply structure in a wire electric discharge machine according to the present invention,
FIG. 2 is a front view showing an outline of a power supply structure in the wire electric discharge machine shown in FIG. In this embodiment, the outline of the wire electric discharge machine is the same as that shown in FIG. 6, and the same components are denoted by the same reference numerals, and the description thereof will not be repeated.

The power supply structure in the wire electric discharge machine shown in FIG. 1 is a power supply structure for supplying an electric discharge machining current to the wire electrode 1 guided by the lower wire head 57 by the power supply 2. Wire electrode 1 introduced from nozzle 60
Is a pair of guides 61, 6 in the lower wire head 57.
1, the vehicle travels while contacting the power supply 2 disposed between the guides 61, and receives a current for electric discharge machining from the power supply 2. One end of a rotating shaft 5 rotatably supported on a frame 3 of the electric discharge machine via a bearing 4 has a direction changing roller 54 for guiding the traveling of the wire electrode 1.
A bevel gear 6 is attached to the other end of the rotating shaft 5.
Is provided. A rotating shaft 7 extending in a direction orthogonal to the rotating shaft 5 is rotatably supported on the frame 3.
A bevel gear 8 that meshes with the bevel gear 6 is attached to one end of the rotating shaft 7, and a spur gear 9 is attached to the other end of the rotating shaft 7.

A power supply 2 for supplying a processing current while slidingly contacting the wire electrode 1 is formed as a rotating body having a gear 11 meshing with a spur gear 9 at an upper end which is one end. It has a cylindrical portion 12 extending downward integrally. Block electrode 13 attached to frame 3
Is formed with a fitting hole 15 that is connected to a power supply wire 14 from a power supply and that rotatably fits the cylindrical portion 12 of the power supply 2. The cylindrical portion 12 is fitted in the fitting hole 15 of the block electrode 13 in a sliding contact state. The electric discharge machining current is supplied from the fitting hole 15 of the block electrode 13 to the cylindrical portion 12 which is rotatably supported in the fitting hole 15, and is thus supplied to the power supply 2.

The power supply 2 has a through hole 16 in which the wire electrode 1 runs. The through-hole 16 has a narrow throat portion 17 at the center, and is formed to have a shape that smoothly opens and opens toward both ends. The through hole 16 has a hole center line CC coincident with a rotation axis which is a rotation center line of the power supply 2, and the hole inner surface 18 has a rotating body (a through hole having the hole center line CC as a rotation axis). 16 is formed so as to coincide with the surface of the rotating body having the curve indicating 16 as a generating line. The traveling path of the wire electrode 1 is the through hole 1
6, the wire electrode 1 is deviated from the hole center line CC by a small offset amount E (FIG. 2).
It is in sliding contact with the throat 17.

When the wire electrode 1 is guided by the rotation of the direction change roller 54 in order to perform the electric discharge machining of the workpiece W, the bevel gears 6, 8 and the spur gear 9 are rotated in accordance with the rotation of the direction change roller 54. , 11 also rotate. When the power supply 2 rotates, the hole center line CC serving as the center of rotation of the through hole 16 and the traveling path of the wire electrode 1 are deviated, so that the wire formed in the throat portion 17 of the power supply 2 is displaced. The sliding contact S with the electrode 1 moves in the circumferential direction one after another on the inner peripheral surface of the throat portion 17, and the wire electrode 1 does not continuously slide on the same position with the power supply 2 for a long time. . Therefore, a running flaw is not formed on the power supply 2 due to abrasion caused by the wire electrode 1 slidingly contacting the same location with the power supply 2, and the wear of the power supply 2 is made uniform, and And the power supply state is stabilized.

FIG. 3 is a schematic view showing another embodiment of the power supply structure in wire electric discharge machining according to the present invention. FIG.
Since the embodiment shown in FIG. 1 has the same structure except that the rotation transmission mechanism between the rotating shaft 7 and the power supply 20 is different, the same reference numerals are given to the same components and parts, and the detailed description is omitted again. . According to the embodiment shown in FIG. 3, the other end of the rotating shaft 7 has a pulley 28 instead of the spur gear 9 shown in FIGS.
A pulley 21 around which a belt 29 is wound is formed between the power supply 20 and the pulley 28. Since the structure of the power supply 20 other than the pulley unit 21 and the relationship with the wire electrode 1 are the same as those of the power supply 2 shown in FIGS. 1 and 2, the description will not be repeated here.

FIGS. 4 and 5 are schematic views showing still another embodiment of the power supply structure in wire electric discharge machining according to the present invention. FIG. 4 is a perspective view showing still another embodiment of the power supply structure in wire electric discharge machining. FIG. 5 is a schematic side view of the power supply structure in the wire electric discharge machining shown in FIG. A drive pulley 36 is attached to the other end of the rotating shaft 35 having the direction change roller 54 attached to one end. Rotary axis 3
The driving pulley 36 is attached to a rotating shaft 39 disposed in parallel with the driving pulley 36.
A driven pulley 38 is attached to the drive pulley 36, and a belt 37 is wound between the drive pulley 36 and the driven pulley 38. A worm 41 is attached to the rotating shaft 39, and the worm 41 meshes with a worm wheel 42 provided integrally with the power supply 40. The structure of the power supply 40 other than the worm wheel portion 42 and the relationship with the wire electrode 1 are the same as those of the power supply 2 shown in FIGS. 1 and 2, and thus the description thereof will not be repeated here. .

Although the power supply structure provided on the lower wire head 57 has been described, it is apparent that a similar power supply structure is provided on the upper wire head 56 as well. Even when the wire electrode 1 travels in the vertical direction due to the rotation of the power supply 2, the power supply 2 does not have a running flaw. Further, since the rotation of the power supply 2 is slow, no spark is generated between the wire electrode 1 and the power supply 2 even during the electric discharge machining.

In the above embodiment, an example has been described in which the power supply is rotatably arranged around a rotation axis (center line of the through hole) parallel to the traveling direction of the wire electrode. It is only necessary that the sliding contact with the wire electrode is changed to a new sliding contact one after another, so that the rotation direction of the power supply for changing the sliding contact is not limited to the rotation about the axis as described above. For example, the power supply may be slid in a direction intersecting the traveling direction of the wire electrode while the wire electrode is traveling,
Alternatively, the sliding contact may be changed by a combination of rotating around an axis intersecting the traveling direction of the wire electrode and sliding in the intersecting direction.

[0027]

According to the power supply structure in the wire electric discharge machining according to the present invention, the sliding contact between the power supply and the wire electrode is changed while the wire electrode is running. The wire electrode of the power supply will be in sliding contact with the wire electrode with new sliding contacts one after another,
The situation in which the traveling wire electrode keeps sliding on the power supply at the same location is avoided. Therefore, the power supply is not damaged by the abrasion caused by the continuous contact of the wire electrodes with the same sliding contact, so that the life of the power supply can be significantly extended and the electric power supply state can be stabilized. Can be done. In addition, since large scratches do not occur in the power supply, the electric power supply state is stabilized, and the accuracy of electric discharge machining can be improved.

[Brief description of the drawings]

FIG. 1 is a partially sectional side view showing an outline of an embodiment of a power supply structure in a wire electric discharge machine according to the present invention.

FIG. 2 is a front view showing an outline of a power supply structure in the wire electric discharge machine shown in FIG.

FIG. 3 is a schematic view showing another embodiment of a power supply structure in wire electric discharge machining according to the present invention.

FIG. 4 is a schematic perspective view showing still another embodiment of a power supply structure in wire electric discharge machining.

5 is a schematic side view of a power supply structure in the wire electric discharge machining shown in FIG.

FIG. 6 is a view schematically showing a conventional wire electric discharge machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire electrode 2, 20, 40 Electron supply 5, 35 Rotating shaft 11 Gear (rotation input part) 12 Cylindrical part 13 Block electrode 15 Fitting hole 16 Through hole 17 Throat part 21 Pulley (rotation input part) 29 Belt 41 Worm 42 Worm wheel (rotation input unit) 54 Direction changing roller 56 Upper wire head 57 Lower wire head W Workpiece S Sliding contact CC hole center line

Claims (7)

[Claims] 1. An electric discharge machine for electric discharge machining of a workpiece by causing a discharge phenomenon to occur between the wire electrode and the workpiece while supplying power by sliding a feeder electrode on the traveling wire electrode. A power supply structure in a wire electric discharge machine, wherein a sliding contact of the power supply electrode with respect to the wire electrode is changed while the electrode is running. 2. The power supply structure in a wire electric discharge machine according to claim 1, wherein the sliding contact of the power supply is changed in a direction intersecting a running direction of the wire electrode in the power supply. . 3. The feeder is a rotating body having a through-hole whose hole center line coincides with the rotation axis thereof, and the wire feeder is inserted into the through-hole by rotating the feeder. The power supply structure in the wire electric discharge machine according to claim 2, wherein the slide contact of the feeder that slides is changed. 4. The throat according to claim 3, wherein a throat portion is formed in the through hole at a center in a hole center line direction, and the sliding contact of the power supply is formed in the throat portion. Power supply structure in the wire electric discharge machine. 5. The wire electric discharge machine further comprises a wire guide for guiding the wire electrode to the workpiece, and the power supply is formed on a block electrode provided in the wire guide. A cylindrical portion rotatably fitted in the fitting hole and electrically connected to the block electrode, and a rotational force extending from the cylindrical portion to the outside of the fitting hole and rotating the power supply is introduced. The power supply structure in the wire electric discharge machine according to any one of claims 1 to 4, further comprising: 6. The rotation input section of the power supply, wherein the rotation input portion is engaged with a gear to which a rotational force is input by meshing the gear, a pulley to which a rotational force is input via a wound belt, or a worm. 6. A worm wheel to which a rotational force is input by a worm wheel.
A power supply structure in the wire electric discharge machine according to item 1. 7. A rotational force is input to the rotation input unit of the power supply via a transmission mechanism from a rotation shaft that rotates a roller disposed in a wire electric discharge machine for guiding and running the wire electrode. 6. The method according to claim 5, wherein
Or a power supply structure in the wire electric discharge machine according to 6.