WO2009142140A1

WO2009142140A1 - Discharge processing apparatus

Info

Publication number: WO2009142140A1
Application number: PCT/JP2009/059002
Authority: WO
Inventors: 中川　孝幸; 三宅　英孝; 佐藤　達志; 進士　忠彦; 暁友張; 浩基森田
Original assignee: 三菱電機株式会社; 国立大学法人東京工業大学
Priority date: 2008-05-20
Filing date: 2009-05-14
Publication date: 2009-11-26
Also published as: JPWO2009142140A1; JP5202624B2

Abstract

The apparatus is equipped with a rotary wheel (11) supported in a freely rotatable manner on a base (80) via a bearing (19), a rotary drive device (12) that is placed on said base (80) and that rotates said rotary wheel (11) via a power transmission part (12a), a spindle (13) that is disposed roughly concentrically with said rotary wheel (11) in a center hole in said rotary wheel (11) and that holds a discharge electrode (70), a non‑contact power transmission part (14) that transfers rotational power contactlessly from said rotary wheel (11) to said spindle (13), a contact power supply part (15) that is in contact with said rotary wheel (11) and that supplies discharge power to said rotary wheel (11), and a slack wire (16) that electrically connects said rotary wheel (11) and said spindle (13).

Description

EDM machine

The present invention relates to an electric discharge machining apparatus for removing a workpiece by applying a voltage between an electrode and a workpiece and generating an electric discharge between the electrodes, and particularly relates to supplying electric power to a rotating electrode. Is.

Conventional electric discharge machining devices supply power to an electrode through a power supply brush or a bearing that is in contact with the electrode or a spindle that holds the electrode when the electrode rotates (see, for example, Patent Document 1).

Further, the rotational power of the spindle supported in a non-contact state with the base is obtained by a motor mounted inside (see, for example, Patent Document 2).

JP 2000-61733 A Japanese Patent No. 3736100

However, in the conventional electric discharge machining apparatus described in Patent Document 1, a brush or a bearing is brought into contact with a rotating spindle in order to supply electric power to the electrodes. For this reason, there has been a problem that the operating speed and the response frequency in the direction of the rotation axis of the spindle and the direction perpendicular thereto are reduced by the action of the frictional force. Furthermore, there is a problem in that fluctuations synchronized with the rotation are generated in the spindle control system, and high-precision control performance cannot be obtained.

Further, the conventional electric discharge machining apparatus described in Patent Document 2 generates rotational power by a motor mounted therein. For this reason, it is difficult to obtain high-precision control performance due to heat accumulation inside the spindle, expansion of the spindle, deterioration of control performance, and the like. In addition, there is a problem that it is necessary to lengthen the device in the direction of the rotation axis in order to generate sufficient rotational power. Furthermore, there is a problem that the operating speed and response frequency in the direction of the rotation axis of the spindle and the direction perpendicular thereto are reduced by the action of the frictional force.

The present invention has been made in view of the above, and it is an object of the present invention to obtain an electric discharge machining apparatus in which there is no frictional force acting on the spindle and the motor heat is not trapped.

In order to solve the above-described problems and achieve the object, the present invention includes a rotating wheel rotatably supported on a base via a bearing, and the rotating wheel installed on the base via a power transmission unit. A rotary drive device for driving, a spindle disposed substantially concentrically with the rotating wheel in a central hole of the rotating wheel and holding a discharge electrode, and non-contact power transmission for transmitting rotational power from the rotating wheel to the spindle in a non-contact manner And a contact power feeding unit that contacts the rotating wheel and supplies discharge power to the rotating wheel, and a slack wire that electrically connects the rotating wheel and the spindle.

The electrical discharge machining apparatus according to the present invention greatly suppresses horizontal and vertical disturbances from the rotary drive device to the spindle and transmits almost only rotational power to the spindle, so the spindle is highly accurate in the horizontal and vertical directions. Can be controlled. In addition, it is possible to smooth the rotation unevenness generated in the rotation drive device, and to smoothly rotate the spindle.

Also, since the rotation drive device is installed outside, the length of the base and spindle in the rotation axis direction can be shortened. In addition, since the heat generated by the rotary drive is hardly transmitted to the spindle, the control performance is prevented from deteriorating due to thermal expansion and thermal deformation of the spindle, and the grease life of the bearing is prevented from being lowered. There is an effect that can be done.

FIG. 1 is a longitudinal sectional view schematically showing Embodiment 1 of an electric discharge machining apparatus according to the present invention. FIG. 2 is a top view showing a non-contact power transmission unit of the electric discharge machining apparatus according to the first embodiment. FIG. 3 is a partial perspective view showing the non-contact power transmission unit of the second embodiment of the electric discharge machining apparatus according to the present invention. FIG. 4 is a partial perspective view showing the non-contact power transmission unit of the third embodiment of the electric discharge machining apparatus according to the present invention. FIG. 5 is a longitudinal sectional view schematically showing Embodiment 4 of the electric discharge machining apparatus according to the present invention. FIG. 6 is a top view showing the non-contact power transmission unit of the fifth embodiment of the electric discharge machining apparatus according to the present invention. FIG. 7 is a partial perspective view showing the non-contact power transmission unit of the fifth embodiment.

Hereinafter, embodiments of an electric discharge machining apparatus according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
1 is a longitudinal sectional view schematically showing Embodiment 1 of an electric discharge machining apparatus according to the present invention, and FIG. 2 is a top view showing a non-contact power transmission portion of the electric discharge machining apparatus of Embodiment 1. FIG. is there.

As shown in FIG. 1, an electric discharge machining apparatus 91 according to Embodiment 1 includes a rotating wheel 11 that is rotatably supported by a base 80 via a bearing 19, and a pinion 12b and a gear 12c that are installed on the base 80. A motor 12 as a rotational drive device that rotates the rotating wheel 11 via the power transmission unit 12 a and a vertical drive device 17 installed on the base 80 are rotatably suspended via a rotary joint 18, A spindle 13 that is arranged substantially concentrically with the rotating wheel 11 in the hole and holds the discharge electrode 70, a non-contact power transmission unit 14 that transmits power from the rotating wheel 11 to the spindle 13 in a non-contact manner, and a contact with the rotating wheel 11. A contact power supply unit 15 for supplying discharge power, and a slack conducting wire 16 for electrically connecting the rotating wheel 11 and the spindle 13. The vertical drive device 17 is composed of a linear actuator such as a ball screw or a linear motor.

The spindle 13 is rotationally driven in a non-contact manner by the rotating wheel 11 and the non-contact power transmission unit 14, and is driven up and down by a vertical drive device 17. A rotating wheel side non-contact power transmission unit 14a is provided in a central hole of the rotating wheel 11, and a spindle side non-contact power transmission unit is provided on an outer peripheral portion of the spindle 13 at a portion facing the rotating wheel side non-contact power transmission unit 14a. 14 b is provided to transmit the rotational power of the rotating wheel 11 to the spindle 13.

As shown in FIG. 2, the rotating wheel side non-contact power transmission unit 14 a is a so-called Halbach array multi-pole field magnetic pole formed in an annular shape, and generates a magnetic flux radially outward in an angle range of 22.5 °. A plurality of (four) main magnetic pole magnets 14an magnetized so as to be generated, and a magnetic flux is generated radially inward in an angle range of 22.5 ° apart from the main magnetic pole magnet 14an by 22.5 °. A plurality of magnetized main pole magnets 14as and a plurality of magnetized main pole magnets 14as and a plurality of magnetized magnets so as to generate a magnetic flux in the direction of the main pole magnet 14as in the circumferential direction within an angle range of 22.5 ° between the main pole magnets 14an and 14as. (Eight) yoke magnets 14ay.

The spindle-side non-contact power transmission portion 14b is a magnetic body formed in an annular shape having a plurality of (eight) main magnetic pole magnets 14an and 14as and a plurality of protrusions 14bt facing the rotating wheel. As shown in FIG. 2, since a magnetic attractive force is generated between the main magnetic pole magnets 14an, 14as and the protrusion 14bt, when the rotating wheel 11 (the rotating wheel side non-contact power transmission unit 14a) rotates, In synchronization with this, the spindle 13 (spindle side non-contact power transmission portion 14b) rotates.

By appropriately adjusting the magnetic flux density of the main magnetic pole magnets 14an and 14as, the number of magnetic poles and the number of protrusions 14bt, the spindle 13 can be connected to the rotating wheel 11 without increasing the vertical length of the non-contact power transmission portions 14a and 14b. Power necessary for synchronous rotation can be transmitted. However, if the magnetic attraction force is increased more than necessary, the vertical vibration and rotation unevenness of the rotating wheel 11 are transmitted to the spindle 13 and the control performance of the spindle 13 is deteriorated.

As shown in FIG. 1, the slack conducting wire 16 that electrically connects the conductive portion 11a of the rotating wheel 11 and the conductive portion 13a of the spindle 13 is flexible and long enough to hang down (sag). . A discharge electrode 70 is chucked on the spindle 13. The discharge electrode 70 faces the workpiece 72 installed in the machining tank 71.

The contact power feeding part 15 is pressed against the conductive part 11a of the rotating wheel 11 by a spring that takes a reaction force on the base 80. Even if the rotating wheel 11 rotates, the contact power feeding part 15 and the conductive part 11a of the rotating wheel 11 Are always electrically connected. The machining power source 73 applies a voltage between the discharge electrode 70 and the workpiece 72 via the contact power feeding unit 15, the rotating wheel 11, the slack conducting wire 16 and the spindle 13.

Since the spindle 13 is connected to the

power sources

12 and 17 only through the rotary joint 18 and the slack conducting wire 16, it does not receive vertical frictional force when transmitting rotational power. Therefore, the load in the vertical direction is reduced, and high-speed drive control is possible. In addition, since the disturbance is hardly received, highly accurate drive control can be performed.

Also, since the motor 12 for rotation is installed outside the base 80, the length of the spindle 13 can be shortened. Furthermore, since the motor 12 for rotation is installed outside the base 80, there is no direct heat transfer to the spindle 13, there is no deterioration in control performance due to thermal expansion of the spindle 13, and the grease life of the rotary joint 18 The control performance can be maintained for a long time.

Embodiment 2. FIG.
FIG. 3 is a partial perspective view showing the non-contact power transmission unit of the second embodiment of the electric discharge machining apparatus according to the present invention. As shown in FIG. 3, in the non-contact power transmission unit 24 according to the second embodiment, the length in the vertical direction (rotational axis direction) of the spindle-side non-contact power transmission unit 24b is the rotating wheel-side non-contact power transmission unit 24a. Is sufficiently longer than the vertical movement range (stroke) of the spindle 13. The vertical length of the rotating wheel side non-contact power transmission unit 24a is made sufficiently longer than the vertical length of the spindle side non-contact power transmission unit 24b to be longer than the vertical movement range (stroke) of the spindle 13. May be.

According to the non-contact power transmission unit 24 of the second embodiment, even if the spindle 13 moves in the vertical direction (rotational axis direction), the facing area between the non-contact

power transmission units

24a and 24b does not always increase or decrease. The transmission efficiency of rotational power does not fluctuate, and highly accurate control performance can be obtained.

Embodiment 3 FIG.
FIG. 4 is a partial perspective view showing the non-contact power transmission unit of the third embodiment of the electric discharge machining apparatus according to the present invention. As shown in FIG. 4, in the non-contact power transmission unit 34 according to the third embodiment, the vertical lengths (rotational axis directions) of the spindle-side non-contact power transmission unit 34b and the rotating wheel-side non-contact power transmission unit 34a are as follows. The spindle 13 is sufficiently longer than the vertical movement range (stroke) of the spindle 13.

According to the non-contact power transmission unit 34 of the third embodiment, even if the spindle 13 moves in the vertical direction, the rate of change in the facing area between the non-contact

power transmission units

34a and 34b is small, so the transmission efficiency of the rotational power Hardly fluctuates, and highly accurate control performance can be obtained.

Embodiment 4 FIG.
FIG. 5 is a longitudinal sectional view schematically showing Embodiment 4 of the electric discharge machining apparatus according to the present invention. In the electric discharge machining apparatus 95 of the fourth embodiment shown in FIG. 5, the same parts as those of the electric discharge machining apparatus 91 of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. Although not shown, the rotating wheel 11 and the spindle 53 are electrically connected by a slack conducting wire.

As shown in FIG. 5, the spindle 53 of the electric discharge machining apparatus 95 according to the fourth embodiment is formed in a long cylindrical shape, and has a disk portion 53 b in the middle portion. An upper and lower drive upper coil 54 a is disposed coaxially with the spindle 53 on the upper side of the disc portion 53 b. A lower coil 54b for vertical driving is arranged coaxially with the spindle 53 below the disk portion 53b.

On the upper left side of the spindle 53, an upper left coil 55a is disposed on the left side of the spindle 53 with the coil axis orthogonal to the axis of the spindle 53. On the upper right side of the spindle 53, an upper right coil 55b is arranged on the right side of the spindle 53 with the coil axis orthogonal to the axis of the spindle 53.

On the upper front side of the spindle 53, an upper front coil (not shown) is disposed on the front side of the spindle 53 with the coil axis orthogonal to the axis of the spindle 53. On the upper rear side of the spindle 53, an upper rear coil (not shown) is disposed on the rear side of the spindle 53 with the coil axis orthogonal to the axis of the spindle 53.

On the lower left side of the spindle 53, a lower left coil 56a is disposed on the left side of the spindle 53 with the coil axis orthogonal to the axis of the spindle 53. On the lower right side of the spindle 53, a lower right coil 56b is arranged on the right side of the spindle 53 with the coil axis orthogonal to the axis of the spindle 53.

A lower front coil (not shown) is disposed on the front side of the spindle 53 with the coil axis orthogonal to the axis of the spindle 53 on the lower front side of the spindle 53. On the lower rear side of the spindle 53, a lower rear coil (not shown) is disposed on the rear side of the spindle 53 with the coil axis orthogonal to the axis of the spindle 53.

The vertical position of the spindle 53 can be controlled by adjusting the current flowing through the upper and lower drive

upper coils

54a and 54b. When the current of the upper and lower drive upper coil 54a is increased, the spindle 53 moves upward, and when the current of the lower and upper drive lower coil 54a is increased, the spindle 53 moves downward.

By adjusting the current flowing through the upper left coil 55a and the upper right coil 55b, the position of the upper part of the spindle 53 in the left-right direction can be controlled. Further, by adjusting the current flowing through the upper front coil and the upper rear coil (not shown), the position of the upper portion of the spindle 53 in the front-rear direction can be controlled.

Further, by adjusting the current flowing through the lower left coil 56a and the lower right coil 56b, the position of the lower part of the spindle 53 in the left-right direction can be controlled. Further, by adjusting the current flowing in the lower front coil and the lower rear coil (not shown), the position of the lower portion of the spindle 53 in the front-rear direction can be controlled.

Detection values of an unillustrated vertical position sensor, upper left / right position sensor, upper front / rear position sensor, lower left / right position sensor, and lower front / rear position sensor are input to a CPU (not illustrated), and the vertical position, left / right front / rear position, and tilt commanded by the spindle 53 are input. The current of the ten coils is controlled through a power amplifier (not shown) so as to be in the posture.

In the electric discharge machining apparatus 95 according to the fourth embodiment, the mass of the drive unit (spindle 53) is small, and there is almost no external force such as frictional force. Therefore, the spindle 53 is rotated and translated (in the direction of the rotation axis or rotation). High-speed and high-accuracy drive control is possible in all directions (perpendicular to the axis).

Embodiment 5. FIG.
FIG. 6 is a top view showing the non-contact power transmission unit of the fifth embodiment of the electric discharge machining apparatus according to the present invention, and FIG. 7 is a partial perspective view showing the non-contact power transmission unit of the fifth embodiment. .

As shown in FIGS. 6 and 7, in the non-contact power transmission unit 44 of the fifth embodiment used in the electric discharge machining apparatus 95 of the fourth embodiment, the upper part of the non-contact power transmission unit 44 a on the rotating wheel side is S. The upper and lower sides of an annular permanent magnet 44am as a pole are fixedly sandwiched between annular magnetic bodies 44aj having a plurality of (eight) projections 44at on the spindle side.

Further, the spindle-side non-contact power transmission unit 44b sandwiches the upper and lower sides of an annular permanent magnet 44bm whose upper part is an N pole with an annular magnetic body 44bj having a plurality of (eight) projections 44bt on the rotating wheel side. It is fixed. The spindle-side non-contact power transmission unit 44b is disposed below the rotating wheel-side non-contact power transmission unit 44a.

According to the non-contact power transmission unit 44 of the fifth embodiment, the non-contact power transmission unit 44 transmits the power of the rotating wheel 11 to the spindle 53 and generates a magnetic attraction force that attracts the spindle 53 upward. The spindle 53 can be prevented from descending due to gravity. In addition, since it is not necessary to separately provide a member for gravity compensation, the length of the electric discharge machining apparatus 95 in the vertical direction can be shortened.

As described above, the electric discharge machining apparatus according to the present invention is useful as a device capable of controlling the spindle in the horizontal and vertical directions with high accuracy.

DESCRIPTION OF SYMBOLS 11 Rotating wheel 11a Conducting part 12 Motor (rotary drive device)
12a Power transmission unit 12b Pinion 12c Gear 13 Spindle 13a Conducting unit 14 Non-contact power transmission unit 14a Rotating wheel side non-contact power transmission unit 14an, 14as Main magnetic pole magnet 14ay Yoke magnet 14b Spindle side non-contact power transmission unit 14bt Protrusion 15 Contact power supply Part 16 Loose wire 17 Vertical drive device (linear motion motor)
18 Rotating joint 19 Bearing 24 Non-contact power transmission unit 24a Rotating wheel side non-contact power transmission unit 24b Spindle side non-contact power transmission unit 34 Non-contact power transmission unit 34a Rotating wheel side non-contact power transmission unit 34b Spindle side non-contact power transmission Part 44 Non-contact power transmission unit 44a Rotary wheel side non-contact power transmission unit 44aj Magnetic body 44at Protrusion 44am Permanent magnet 44b Spindle side non-contact power transmission unit 44bj Magnetic body 44bt Protrusion 44bm Permanent magnet 53 Spindle 53b Disk part 54a For vertical drive Upper coil 54b Upper / lower drive lower coil 55a Upper left coil 55b Upper right coil 56a Lower left coil 56b Lower right coil 70 Discharge electrode 71 Work tank 72 Work piece 73 Work power supply 80

Base

91, 95 Electric discharge machine

Claims

A rotating wheel rotatably supported by a base via a bearing;
A rotational drive device installed on the base and rotating the rotating wheel via a power transmission unit;
A spindle that is disposed substantially concentrically with the rotating wheel in a central hole of the rotating wheel and holds a discharge electrode;
A non-contact power transmission unit that transmits rotational power from the rotating wheel to the spindle in a non-contact manner;
A contact power feeding unit that contacts the rotating wheel and supplies discharge power to the rotating wheel;
A slack conducting wire for electrically connecting the rotating wheel and the spindle;
An electric discharge machining apparatus comprising:
The electric discharge machining apparatus according to claim 1, wherein the rotary drive device is installed outside the base.
The electric discharge machining apparatus according to claim 1, wherein the non-contact power transmission unit transmits rotational power in a non-contact manner by a magnetic attraction force.
The length of at least one of the annular non-contact power transmission unit and the annular spindle-side non-contact power transmission unit of the non-contact power transmission unit is longer than the spindle stroke. The electric discharge machining apparatus according to claim 1.
The electric discharge machining apparatus according to claim 1, wherein the spindle is supported on the base in a non-contact manner by a magnetic attraction force.
5. The electric discharge machining apparatus according to claim 4, wherein the non-contact power transmission unit generates a magnetic attraction force that attracts the spindle upward.