JPH10156631A - Electrode feeding device for electrical discharge machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform adjusting work of a clearance between an electrode and a power feeding electrode and changing work of the power feeding electrode in an electrode feeding device for electrical discharge machining. SOLUTION: A power feeding holding member 17 integrated with a power feeding electrode 16 and for holding the power feeding electrode 16 is detachably arranged to a casing 14, and a hexagon socket set screw 18 capable of being displaced in the extending and contracting direction of a second piezoelectric element 12 is arranged. Therefore, a clearance δ can be adjusted by displacing the hexagon socket set screw 18 in the extending and contracting direction of the second piezoelectric element 12. Moreover, the power feeding electrode 16 can be easily changed by removing the power feeding holding member 17 from the casing 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrode feeder for electric discharge machining which feeds electrodes (electrode wires) of an electric discharge machine, and uses a piezoelectric element (piezo element) as a feed mechanism.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 5-146919 discloses an electrode feeder for electric discharge machining, in which a first piezoelectric element which expands and contracts in a longitudinal direction (axial direction) of an electrode wire and a direction perpendicular to the longitudinal direction of the electrode wire. Second and third expanding / contracting (radially)
There is disclosed a device having a piezoelectric element and controlling the “feed” or “return” of the electrode wire by controlling the expansion and contraction of the piezoelectric element.

[0003]

By the way, the inventors made a prototype of an electrode feeder for electric discharge machining based on the above-mentioned publication and found the following problems. That is, FIG. 8 shows the outline of the second piezoelectric element (hereinafter abbreviated as “piezoelectric element”) 12 in the prototype.
Is used as an actuator for pressing or detaching the electrode wire 10 similarly to the above publication.

Specifically, a power supply electrode 16 buried in a lid 25 screwed to the casing 14 and a piezoelectric element 1
2 and an insulating member 19 provided on one end side, and the electrode wire 10 is provided between the power supply electrode 16 and the insulating member 19. Then, by controlling the voltage applied to the piezoelectric element 12, the piezoelectric element 12 expands and contracts, and the power supply electrode 16 and the insulating member 19 compress the electrode wire 10.
The withdrawal is performed.

However, the diameter of the electrode wire 10 needs to be changed depending on the size and material of the workpiece, etc.
The gap (clearance) δ between 0 and the feeding electrode fluctuates. On the other hand, since the amount of expansion and contraction of the piezoelectric element 12 is generally as small as tens of microns, when the amount of change in the gap δ is large, the change in the gap δ can be dealt with only by the expansion and contraction of the piezoelectric element 12. Can not.

[0006] Therefore, a means for adjusting the gap δ by arranging a spacer (shim) 30 for adjusting the gap between the piezoelectric element 12 and the casing 14 and changing the thickness of the spacer 30 has been considered. However, this means requires a large number of spacers 30 having different thicknesses in units of microns in order to cope with various changes in the gap δ. Further, in the above-mentioned prototype, since the power supply electrode 16 is embedded in the lid 25, when the power supply electrode 16 is worn, the power supply electrode 1 together with the lid 25 is provided.
6 needs to be replaced, and the replacement operation takes time.

For this reason, there is a problem that the cost (running cost) for maintaining the electrode feed device for electric discharge machining increases, and the production cost of the workpiece increases. In view of the above, an object of the present invention is to make it possible to easily perform adjustment of a gap and replacement of a power supply electrode in an electrode feeding device for electric discharge machining.

[0008]

The present invention uses the following technical means to achieve the above object. Claim 1
According to the invention described in Item 8, the power supply holding member (17) integrally holding the power supply electrode (16) with the power supply electrode (16) is detachably provided to the casing (14), and
It has a pressing member (18, 26) displaceable in the direction of expansion and contraction of the second piezoelectric element (12).

By displacing the pressing members (18, 26), the electrode (10) and the power supply electrode (16) are displaced.
The gap with the (power supply holding member 17) can be adjusted. Therefore, as described in the section of “Problems to be Solved by the Invention”, the gap can be easily adjusted as compared with the means for adjusting the gap by using the gap adjusting spacer (shim).

Further, since the power supply electrode (16) and the power supply holding member (17) are integrated, the power supply holding member (1) is provided.
By detaching 7) from the casing (14),
The power supply electrode (16) can be easily replaced. As described above, according to the present invention, the cost (running cost) for maintaining the electrode feeding device for electric discharge machining can be reduced, and therefore, the production cost of the workpiece can also be reduced. .

By the way, as in the second aspect of the present invention, the pressing members (18, 26) may be disposed on the other end of the casing (14) in the expansion and contraction direction of the second piezoelectric element 12 (). Further, as in the third aspect of the present invention, the power supply holding member (17) may be inserted into the casing (14) from a direction orthogonal to a direction in which the second piezoelectric element (12) expands and contracts.

According to the fourth aspect of the present invention, the elastic member (22) for generating an elastic force for pressing the second piezoelectric element (12) toward the other end in the expansion and contraction direction of the second piezoelectric element (12).
Are provided between the second piezoelectric element (12) and the power supply holding member (17). Thereby, the second
Since it is possible to prevent the piezoelectric element (12) from rattling (vibrating) in the casing (14), it is possible to prevent fatigue destruction accompanying the vibration of the second piezoelectric element (12).

By the way, a manual operation section (18b) for displacing the pressing member (18) by manual operation may be provided. Also, as in the invention according to claim 6, the display means (5) for displaying the pressing force detected by the pressing force detecting means (23) to the operator.
a) may be provided. Further, as in the invention according to claim 7, the pressing member (18) and the casing (14) may be screw-connected.

According to the present invention, an actuator (24) for displacing the pressing member (24) is provided so that the pressing force detected by the pressing force detecting means (23) becomes a predetermined value. Alternatively, the operation of the actuator (24) may be controlled. In addition, the code | symbol in the parenthesis of each said means shows the correspondence with the concrete means of embodiment mentioned later.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; (First Embodiment) FIG. 1 is a schematic view showing an outline of an electric discharge machine 100 using an electric discharge machine electrode feeder (hereinafter abbreviated as a feeder) 1 according to the present embodiment. The apparatus 100 includes an electric discharge machine 110 that performs electric discharge machining of the workpiece 2 (work), and an electric discharge machining control unit 120 that controls the electric discharge machine 110.

The electric discharge machine 110 is provided with the feeder 1
An NC axis mechanism 3 for moving the workpiece in a three-dimensional direction and a machining fluid supply device 4 for supplying a machining fluid are provided. On the other hand, the electric discharge machining control unit 120 includes an electrode feeder control device (hereinafter, abbreviated as a control device) 5 for controlling the feeder 1 and an electrode wire for electric discharge machining (hereinafter, abbreviated as an electrode) 10. 2, a penetration detection device 6 for detecting whether or not
It comprises a PZT drive amplifier 7 for amplifying a command signal output from the control device 5, an NC axis control device 8 for controlling the NC axis mechanism 3, and a discharge power supply 9 for generating high frequency and high voltage pulses.

FIG. 2 is a schematic view showing the feeder 1. The basic structure of the feeder 1 and the operation for feeding the electrode 10 are the same as those described in Japanese Patent Application Laid-Open No. 5-146919. Therefore, in this specification, the configuration and operation different from those in the above publication will be mainly described. In FIG. 2, reference numeral 11 denotes a laminated first piezoelectric element which expands and contracts in the longitudinal direction (axial direction) of the electrode 10, and 12 and 13 denote second piezoelectric elements which expand and contract in a direction (radial direction) orthogonal to the longitudinal direction of the electrode 10. It is a piezoelectric element.

Here, the first piezoelectric element 11 corresponds to the first piezoelectric element (7, 17) of the above publication, and the second piezoelectric element 12 corresponds to the first radial piezoelectric element (12, 32) of the above publication. The second piezoelectric element 13 corresponds to the second radial piezoelectric element (20, 40) of the above publication. The reference numerals in parentheses correspond to the above-mentioned publications, and hereinafter, unless otherwise specified, the reference numerals in parentheses indicate those corresponding to the above-mentioned publications.

FIG. 3 shows a cross section taken along line AA of FIG.
14 (8) is a casing for housing the second piezoelectric element 12. Then, a second portion is provided on the bottom portion 14a of the casing 14.
The second piezoelectric element 12 is disposed in a state where the ends of the piezoelectric element 12 in the expansion and contraction direction (vertical direction on the paper) are in contact with each other. Also,
A through hole 15 that penetrates the casing 14 in a direction perpendicular to the direction in which the second piezoelectric element 12 expands and contracts (in a direction perpendicular to the plane of the paper) is formed at one end (upper side in the drawing) of the second piezoelectric element 12 in the casing 14. The electrode 10 is inserted into the through-hole 15 (see FIG. 4B). A power supply electrode 16 for supplying power to the electrode 10 is disposed on the opposite side of the electrode 14 from the second piezoelectric element 12 in the casing 14. In the embodiment, it is held by the plate-shaped power supply holding member 17 in a state of being integrated with the power supply holding member 17 (made of aluminum).

In addition, a portion of the casing 14 corresponding to the power supply holding member 17 has an insertion hole 1 that opens in a direction orthogonal to the direction in which the second piezoelectric element 12 expands and contracts (the direction of the arrow in FIG. 3).
A power supply holding member 17 is detachably inserted into the casing 14 from the insertion hole 14b. In order to make the power supply holding member 17 detachable, a gap 14c is formed between the power supply holding member 17 and the insertion hole 14b at least in the expansion and contraction direction of the second piezoelectric element 12, as shown in FIG. This gap 14c
Thereby, the power supply holding member 17 can be displaced in the expansion and contraction direction of the second piezoelectric element 12.

Reference numeral 18 designates the power supply holding member 17 as the electrode 10
A set screw with a hexagonal hole (hereinafter, abbreviated as a set screw) serving as a pressing member that presses toward the side.
Is disposed on the opposite side of the power supply holding member 17 to the electrode 10 in the casing 14 so as to be displaceable in the expansion and contraction direction of the second piezoelectric element 12. The set screw 18 is held by the casing 14 by the male screw portion 18a being screw-coupled to the female screw portion 14d formed on the casing 14.

Reference numeral 19 denotes an electrical insulator formed of a material having high insulation resistance and abrasion resistance, such as a ceramic material, for holding and contacting the electrode 10. The expansion and contraction of the piezoelectric element 12 is controlled by the electric insulator 1
9 (electrode 10). In addition,
It is desirable that the material of the insulator holding portion 20 is also formed of a material having high insulation resistance and abrasion resistance such as a ceramic material.

Reference numeral 21 denotes an aluminum spacer ring formed in an O-ring shape. A disc spring (elastic member) 22 is provided between the spacer ring 21 and the insulator holding portion 20. Then, the spacer ring 21
The disc spring 22 is disposed between the second piezoelectric element 12 and the power supply holding member 17, and the disc spring 22 connects the second piezoelectric element 12 to the second piezoelectric element via the insulator holding section 20. The elastic force is generated in a direction of pressing toward the other end (the bottom 14a side) in the expansion / contraction direction of the twelve.

Next, the features of this embodiment will be described. According to the present embodiment, the hexagonal hole (manual operation part) 1 of the set screw 18
8b (see FIG. 4 (a)) by inserting a hexagonal wrench and measuring the gap δ (see FIG. 3) between the electrode 10 and the power supply electrode 16 (the power supply holding member 17) with a micrometer or the like, and by manual operation. The gap δ can be adjusted by displacing the set screw 18 in the direction in which the second piezoelectric element 12 expands and contracts.

Therefore, as described in the section of “Problems to be Solved by the Invention”, the adjustment of the gap δ is easier than the means for adjusting the gap δ using the spacer (shim) for adjusting the gap. It can be carried out. Further, since the power supply electrode 16 and the power supply holding member 17 are integrated, the power supply holding member 17 is removed from the casing 14 with the set screw 18 loosened (the set screw 18 is displaced upward in FIG. 2). The power supply electrode 16 can be easily replaced by detaching the power supply electrode 16.

As described above, according to the present embodiment, the cost (running cost) for maintaining the feeder 1 can be reduced, so that the manufacturing cost of the workpiece can be reduced. it can. Further, the second piezoelectric element 12
Is pressed toward the bottom 14a by the disc spring 22, so that the second piezoelectric element 12 can be prevented from rattling (vibrating) in the casing 14.
It is possible to prevent fatigue destruction caused by the vibration of the second piezoelectric element 12.

In this embodiment, the set screw 18 is used as the pressing member. However, the pressing member is not limited to this, and an ordinary bolt or a tapered pin may be used. (Second Embodiment) In the present embodiment, in order to easily adjust the set screw 18, when the gap δ is a predetermined value, the power supply holding member 17 when the electrode 10 is crimped (clamped).
This is based on the fact that the pressing force (pressure) acting on the target has a predetermined value.

Specifically, as shown in FIG. 5, between the set screw 18 and the power supply holding member 17, a pressure sensor (push) for detecting a pressing force (pressure) exerted on the power supply holding member 17 by the set screw 18 is provided. A pressure detection unit 23 is provided, and a detection value of the pressure sensor 23 is displayed on a display (display unit) 5a (see FIG. 1) of the control device 5.

Then, the operator applies a voltage to the piezoelectric element 12 and presses (clamps) the electrode 10 while watching the display on the display (CRT) 5a.
The set screw 18 is adjusted so that the detected value of 3 becomes a predetermined value. In the present embodiment, the display 5a is used as the display means. However, the present embodiment is not limited to this, and a display panel including a liquid crystal panel or an LED (light emitting diode), an EL (electroluminescence), A plasma display or the like may be used.

(Third Embodiment) In the above embodiment, the adjustment of the gap δ is performed manually, but in the present embodiment, the gap δ is automatically adjusted based on a signal from the pressure sensor 23. Things. That is, as shown in FIG. 6, a laminated third piezoelectric element 24 that expands and contracts in the same direction as the second piezoelectric element 12 is provided as an actuator on the side opposite to the power supply holding member 17 with the pressure sensor 23 interposed therebetween. At this time, one end of the third piezoelectric element 24 in the expansion and contraction direction is in contact with the lid 25 of the housing 14, and the other end is an interference member (pressing member) that is displaced in conjunction with expansion and contraction of the third piezoelectric element 24. 2
6, the pressure sensor 23 is pressed. Note that 27
Is a bolt for fixing the lid 25 to the housing 14.

In the configuration described above, the pressure sensor 2
3 is input to the control device 5, and the control device 5 expands and contracts the third piezoelectric element 24 so that the detection value of the pressure sensor 23 becomes a predetermined value. In the present embodiment, the third piezoelectric element 24 presses the pressure sensor 23 via the interference member 26. However, the third piezoelectric element 24 may directly press the pressure sensor 23 by eliminating the interference member 26. Good.
In this case, the end in the expansion and contraction direction of the third piezoelectric element 24 can be regarded as the interference member 26, that is, the pressing member.

In this embodiment, the third piezoelectric element 24 is used as an actuator. However, a screw member such as a set screw 18 or a bolt is rotated by a step motor (servo motor) or the like to adjust the gap δ. You may. further,
The gap δ may be adjusted by electromagnetically driving a plunger-shaped pressing member such as a proportional control valve.

(Fourth Embodiment) In the above embodiment, the pressing member such as the set screw 18 or the third piezoelectric element 24 is
Although the piezoelectric element 12 is disposed on one end side (the electrode 10 side) in the expansion and contraction direction of the piezoelectric element 12, in the present embodiment, the pressing member is connected to the second piezoelectric element 12.
(See FIG. 7).

Although FIG. 7 shows the contents of the present embodiment based on the feeder 1 according to the first embodiment, the present embodiment is not limited to this, and the second and third embodiments are not limited thereto. It can also be implemented on the basis of the embodiments. In this case, the pressing force acting on the power supply holding member 17 can be detected by disposing the pressure sensor 23 between the power supply holding member 17 and the lid 25.

In the above-described embodiment, the disc spring 22 is used as a means (elastic member) for generating an elastic force in the direction of pressing the second piezoelectric element 12 toward the other end (the bottom 14a side) in the expansion and contraction direction. Although used, the present invention is not limited to this, and an elastic member such as a coil spring, a leaf spring, or rubber may be used. In the first embodiment, the set screw 18 is adjusted while measuring the gap δ with a micrometer or the like. However, the set screw 18 may be adjusted by controlling the tightening torque of the set screw 18 with a torque wrench or the like. Good.

Although the present invention has been described with reference to the second piezoelectric element 12 as an example, the present invention can also be applied to the second piezoelectric element 13.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an outline of an electric discharge machine.

FIG. 2 is a schematic view showing an electrode feeding device 1 for electric discharge machining.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

4A is a view taken in the direction of arrow B in FIG. 3, and FIG.
It is CC sectional drawing of.

FIG. 5 is a cross-sectional view corresponding to the AA cross section in FIG. 2 according to the second embodiment.

FIG. 6 is a cross-sectional view corresponding to an AA cross section in FIG. 2 according to a third embodiment.

FIG. 7 is a cross-sectional view corresponding to an AA cross section in FIG. 2 according to a fourth embodiment.

FIG. 8 is an explanatory diagram for explaining a problem to be solved by the invention.

[Explanation of symbols]

10: electrode wire, 11: first piezoelectric element, 12, 13
... second piezoelectric element, 14 ... casing, 15 ... through-hole, 1
6 ... power supply electrode, 17 ... power supply holding member, 18 ... hexagon socket set screw (pressing member).

Claims (8)

[Claims] A first piezoelectric element (11) that expands and contracts in the longitudinal direction of an electrode (10) for electric discharge machining, and a second piezoelectric element (12) that expands and contracts in a direction perpendicular to the longitudinal direction of the electrode (10). An electrode feeder for electric discharge machining for sending the electrode (10) toward a workpiece, wherein the casing (1) accommodating the second piezoelectric element (12).
4), and the second piezoelectric element (1) in the casing (14).
An insertion hole (15) formed on one end side of the expansion and contraction direction of 2), penetrates the casing (14) in a direction orthogonal to the expansion and contraction direction of the second piezoelectric element (12), and into which the electrode (10) is inserted. ), Disposed inside the casing (14) on the opposite side of the electrode (10) from the second piezoelectric element (12);
Power supply electrode (16) for supplying power to the electrode (10)
And disposed on the casing (14) so as to be displaceable in the direction of expansion and contraction of the second piezoelectric element (12) and detachable from the casing (14), and integrated with the power supply electrode (16). A power supply holding member (17) for holding the power supply electrode (16); and the power supply holding member (1) of the casing (14).
7) is disposed on the opposite side to the electrode (17) with the second piezoelectric element (12) displaceable in the direction of expansion and contraction, with the power supply holding member (17) facing the electrode (10). And a pressing member (18, 26) for pressing by pressing. 2. A first piezoelectric element (11) that expands and contracts in the longitudinal direction of an electrode (10) for electric discharge machining, and a second piezoelectric element (12) that expands and contracts in a direction perpendicular to the longitudinal direction of the electrode (10). An electrode feeding device for electric discharge machining for sending the electrode (10) toward a workpiece, wherein the second piezoelectric element (12) is replaced by the second piezoelectric element (12).
Casing (14) that is displaceably accommodated in the expansion and contraction direction
And the second piezoelectric element (1) in the casing (14).
An insertion hole (15) formed on one end side of the expansion and contraction direction of 2), penetrates the casing (14) in a direction orthogonal to the expansion and contraction direction of the second piezoelectric element (12), and into which the electrode (10) is inserted. ), Disposed inside the casing (14) on the opposite side of the electrode (10) from the second piezoelectric element (12);
Power supply electrode (16) for supplying power to the electrode (10)
A power supply holding member (17) disposed in the casing (14) so as to be detachable from the casing (14) and integrated with the power supply electrode (16) to hold the power supply electrode (16); The second piezoelectric element (1) in the casing (14).
The other end of the second piezoelectric element (1) is disposed so as to be displaceable in the direction of expansion and contraction of the second piezoelectric element (12).
And (2) a pressing member (18) for pressing the member toward the power supply holding member (17). 3. The power supply holding member (17) is provided with the second power supply holding member (17).
The electrode feed device for electric discharge machining according to claim 1, wherein the electrode feed device is inserted into the casing from a direction perpendicular to a direction in which the piezoelectric element expands and contracts. 4. The second piezoelectric element (12) is provided between the second piezoelectric element (12) and the power supply holding member (17).
4. An elastic member (22) for generating an elastic force for pressing the elastic member toward the other end in the expansion and contraction direction of the second piezoelectric element (12) is provided.
An electrode feeder for electrical discharge machining according to any one of the above. 5. The electrode according to claim 1, wherein the pressing member has a manual operation portion displaced by a manual operation. Feeder. 6. A pressing force detecting means (23) for detecting a pressing force acting on the power supply holding member (17), and a pressing force detected by the pressing force detecting means (23) is displayed to an operator. The electrode feeding device for electric discharge machining according to claim 5, further comprising a display means (5a) for performing the operation. 7. The pressing member has a male screw (18a) formed therein, the casing (14) has a female screw (14d) formed therein, and the pressing member (18) and the casing (14)
The electrode feed device for electric discharge machining according to any one of claims 1 to 6, wherein the electrode feed device is screwed. 8. A pressing force detecting means (23) for detecting a pressing force acting on the power supply holding member (17), and an actuator (2) for displacing the pressing member (24).
4) and a control device (5) for controlling the operation of the actuator (24) such that the pressing force detected by the pressing force detecting means (23) becomes a predetermined value. Item 5. The electrode feeding device for electric discharge machining according to any one of Items 1 to 4.