JPH04201122A - Device for supplying power to movable member - Google Patents

Abstract

PURPOSE:To eliminate mechanical contact of a conductive member with a movable member to prevent them from being worn mechanically by constituting a device in which a magnetic force is generated at a position opposite to a rotating member and, with a magnetic fluid trapped by the magnetic force, supplying power to the movable member through the magnetic fluid. CONSTITUTION:A magnetic force is generated on a conductive member 27 at a position opposite to a rotating member 21 by applying magnetic field to the conductive member 27. A magnetic fluid 29 is trapped by this magnetic force and power is supplied to the rotating member 21 through the conductive member 27 and a magnetic substance 28.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power supply device for movable members such as wire electrodes of electrical discharge machining equipment.

[Prior Art] Conventionally, power supply to a movable member that involves rotational or translational movement has been performed by mechanical contact, similar to power supply to a fixed member. FIG. 7 shows a conventional example of a power supply device for a rotating member, in which (1) is a rotating shaft member, (2a) and (2b) are energizing brushes, and (3) is a rotating shaft member.
is the power source. In the figure, the rotating shaft member (1) is rotated in the direction of arrow H by a rotational drive mechanism (not shown), and when the energized brushes (2a) and (2b) mechanically contact the rotating shaft member (1), power supply(
3) supplying current to the rotating shaft member (1);

Furthermore, Fig. 8 shows a conventional power supply device for wire electrical discharge machining equipment partially hydrated, where (11) is a wire electrode, and (12) is a wire electrode.
is the workpiece, (13) is the processing nozzle, (14a) is the upper wire guide, (14b) is the lower wire guide, (15)
) is a processing power supply, and (16) is a power supply die. In the figure, the wire electrode (11) is being moved in the translational direction as shown by arrow I with respect to the workpiece (12) during machining.
Processing progresses. Current is supplied to the wire electrode (11) via the feeding die (16).

[Problem to be solved by the invention] As described above, in the conventional supply device, the power supply member and the movable member are in mechanical contact, so there is a problem that the power supply member is mechanically worn out due to friction with the movable member. In addition, the heat generated by friction could affect machine accuracy or cause failure. Furthermore, contact between the power supply member and the movable member may temporarily deteriorate due to vibrations caused by mechanical friction, and the power supply may be temporarily cut off.
There has been a problem that discharge or electrolysis occurs between the power supply member and the movable member, resulting in abnormal wear of the power supply member and the movable member.

In addition, conventional wire electrical discharge machining equipment also supplies power to the wire electrode through mechanical contact, and if the contact between the power supply member and the wire electrode temporarily worsens due to vibration of the wire electrode, the power supply may be temporarily cut off. There were problems such as unstable machining and abnormal wear of the power supply member and wire electrode due to discharge or electrolysis occurring between the power supply member and the wire electrode.

Normally, a hard material such as carbide is used for the power supply member of wire electrical discharge machining equipment, so mechanical wear is minimal.
This kind of wear and tear is a problem specific to wire electrical discharge machining equipment, which is caused by electrical discharge or electrolysis occurring between the power supply member and the wire electrode due to the wire electrode vibration caused by the electrical discharge machining reaction force. Further, due to electric discharge in the power feeding section, there were problems such as the wire electrode breaking or the wire electrode and the power feeding member being welded together, making it impossible to continue machining. Furthermore, even when power is being supplied normally, the power supply member usually wears out after about 100 to 200 hours, so it is necessary to periodically replace the power supply member.

As a method to improve these problems, JP-A-63-3
A method using a conductive liquid as disclosed in Japanese Patent No. 18225 has been proposed, but this method has the disadvantage that the liquid adheres to the wire electrode while the wire electrode is running, and the conductive liquid gradually decreases. there were.

The present invention has been made to solve the above problems, and prevents electrical consumption due to discharge and electrolysis in the power feeding section, mechanical consumption due to friction with movable members, wire breakage, etc. The purpose is to obtain a power supply device that provides extremely stable power supply.

[Means for Solving the Problems] A first invention includes a conductive member provided close to a movable member and connected to a power source, and a magnetic field applied to the conductive member to a portion facing the movable member. An electromagnetic induction means for generating magnetic force and a conductive magnetic fluid filled in a portion where the movable member and the conductive member face each other constitute a power supply device to the movable member.

A second invention uses the movable member of the first invention as a wire electrode of a wire electrical discharge machining apparatus, and constitutes a power supply device for the wire electrode.

A third invention uses a mixed fluid in which ferromagnetic fine particles are dispersed in a conductive fluid as the magnetic fluid in the first invention or the second invention.

[Function] The power supply device of the present invention generates magnetic force in the part facing the movable member by applying a magnetic field to the conductive member, captures the magnetic fluid by this magnetic force, and transmits the magnetic fluid through the conductive member and the magnetic fluid. power is supplied to the movable member.

[Embodiment of the invention] FIG. 1 is a structural diagram showing a first embodiment of the first invention.
A) is a plan view, and (b) is a side view. In Figure 1, (21) is a rotating member, (3) is a power supply for energizing, (27)
is a conductive member (
Pole piece), (29) is a conductive magnetic fluid filled between the rotating member (21) and the conductive member (27). The magnetic fluid is made of iron nitride (PexN) or iron oxide (
PexO) and other ferromagnetic particles (usually with average diameter LOn
It is a solid/liquid mixed fluid (colloid) made by dispersing m) in a conductive liquid such as mercury so that the apparently isoelectric liquid has magnetic properties.

(28) is a permanent magnet attached to the conductive member (27).

Next, the operation of this embodiment will be explained.

The rotating member (21) is rotated in the direction of the arrow by a rotation drive mechanism (not shown), or a magnetic force induced by a permanent magnet (28) is generated in the gap between the rotating member (2I) and the conductive member (27). Therefore, even when the rotating member (21) rotates, the magnetic fluid (29) is always attracted between the rotating member (21) and the conductive member (27).

That is, a magnetic path is formed in the conductive member (27), magnetic fluid (29), and rotating member (21) by magnetic flux as shown by arrow K in the figure, and magnetic force (attractive force) is generated. The number is 7 because the magnetic fluid (29) is held. Power supply for energizing (
3) is connected to the conductive member (27), so that the rotating member (21) is energized through the conductive magnetic fluid (29).

FIG. 2 is a diagram showing a second embodiment of the first invention, (
31) is a rotating shaft member, (3) is a power source for energization, (3
7) is a ring-shaped conductive member provided close to the rotating shaft member (31), and (29) is a ring-shaped conductive member provided close to the rotating shaft member (31).
A magnetic fluid having conductivity is filled between 1) and the ring-shaped conductive member (37), and (38) is a ring-shaped permanent magnet attached to the ring-shaped conductive member (37).

Next, the operation of this embodiment will be explained.

The rotating shaft member (31) is rotated by a rotation drive mechanism (not shown), or there is a magnetic force induced by a ring-shaped permanent magnet (38) in the gap between the rotating shaft member (31) and the ring-shaped conductive member (37). Therefore, as in the first embodiment, even if the rotating shaft member (31) rotates, the magnetic fluid (29) is always attracted between the rotating member (31) and the ring-shaped conductive member (37). The state will be as follows. Since surface tension exists in the magnetic fluid (29), if the surface area of the magnetic fluid filled part is small as in this example, it is difficult to separate the magnetic fluid (29) into two poles (N pole, S pole). Instead, it is possible to uniformly hold the magnetic fluid (29) on the inner wall of the ring-shaped conductive member (37). Since the energizing power source (3) is connected to the ring-shaped conductive member (37), the rotating shaft member (31) is energized through the conductive magnetic fluid (29).

Further, FIG. 3 is a diagram showing a third embodiment of the first invention, in which (41) is a flat plate member that moves in translation as shown by arrows C and D in the figure, and (3) is a plate-like member that is energized. (47) is a conductive member provided in close proximity to the flat member (41);
29) is a conductive magnetic fluid filled between the flat plate member (41) and the conductive member (47), and (48) is a permanent magnet attached to the conductive member (47).

Next, the operation of this embodiment will be explained.

The flat member (41) is moved in translation by a drive mechanism (not shown), or the flat member (41) and the conductive member (4
Since the magnetic force induced by the permanent magnet (48) is generated in the gap 7), the magnetic fluid (29) is always It is in a state where it is attracted between the flat member (41) and the conductive member (47). The energizing power source (3) is a conductive member (47)
Since the flat member (41) is connected to the magnetic fluid (29), electricity is applied to the flat plate member (41) through the conductive magnetic fluid (29).

Although each of the embodiments described above uses a permanent magnet as the electromagnetic induction means, it is also possible to use an electromagnet instead of the permanent magnet.

FIG. 4 is a structural diagram showing a first embodiment of the second invention. In the figure, (51) is a wire electrode, (52) is a workpiece, (53) is a processing nozzle, (54a) is an upper wire guide, (54b) is a lower wire guide, (55) is a processing power source, ( 57) is a ring-shaped conductive member provided close to and coaxially with the wire electrode (51), and (29) is between the wire electrode (51) and the ring-shaped conductive member (57). It is a magnetic fluid filled with conductivity. (58) is a ring permanent magnet attached to the ring-shaped conductive member (57).

Next, the operation of this embodiment will be explained.

In the figure, the wire electrode (51) is connected to the workpiece (5) during machining.
The machining progresses while traveling in the translational direction as shown by arrow E with respect to 2). A ring-shaped permanent magnet (58
) is generated by the magnetic path shown by the arrow M, so even if the wire electrode (51) runs, the magnetic fluid (29) always connects the wire electrode (51) and the ring-shaped conductive member (57). ) will be in an adsorbed state. That is, even if the wire electrode (51) is run, the magnetic fluid (29)
or will not decrease. Since the machining power source (55) is connected to the ring-shaped conductive member (57), the machining current necessary for machining is supplied to the wire electrode (51) through the conductive magnetic fluid (29). Processing progresses.

In addition, in this example, an example is shown in which power is supplied by surrounding the wire electrode coaxially using a ring-shaped conductive member and a permanent magnet, or the conductive member of the pole piece (
57a) and a permanent magnet (58a), and a magnetic fluid (57a) is provided between the pole piece (57a) and the wire electrode (51).
29) as shown in FIG. 5 (second embodiment of the second invention).

FIG. 6 shows a power supply device for a wire electrical discharge machining machine using an electromagnet as a third embodiment of the second invention, and FIG.
The same reference numerals as in the figures indicate the same or corresponding parts.

(60) is an electromagnetic coil provided on the outer periphery of the ring-shaped conductive member (57), (61) is a DC power source that supplies DC current to the electromagnetic coil (60), and (62) is an electromagnet that connects the electromagnet to 0N.
This is a 10FF switch.

Next, the operation of this embodiment will be explained.

The wire electrode (51) is moved in the translational direction as shown by arrow G with respect to the workpiece (52) during machining as the machining progresses. During processing, the switch (62) is closed, current is supplied to the electromagnetic coil (60) from the DC power supply (61), and the electromagnet is turned on. This allows the wire electrode (
A magnetic force induced by the electromagnetic coil (60) is generated in the gap between the ring-shaped conductive member (51) and the wire electrode (51), and even if the wire electrode (51) is running, the magnetic fluid (29) is always connected to the wire electrode (51). ) and the ring-shaped conductive member <57). The processing power source (55) is connected to the ring-shaped conductive member (57), and the wire electrode (55) is connected to the ring-shaped conductive member (57).
1) is supplied with a machining current necessary for machining through a conductive magnetic fluid (29), and machining progresses.

In each of the embodiments of the second invention, the power feeding section is provided inside the nozzle, or the power feeding section may be located outside the nozzle. Further, arrows in FIG. 2 and arrows N in FIG. 5 indicate magnetic paths.

In addition, it goes without saying that the first invention can be applied not only to wire electrical discharge machining equipment but also to wire welding equipment, continuous plating equipment, and the like.

[Effects of the Invention] As described above, according to the first invention, a magnetic force is generated in the portion facing the movable member, and while the magnetic fluid is captured by the magnetic force, power is supplied to the movable member via the magnetic fluid. This structure eliminates mechanical contact between the conductive member and the movable member, prevents mechanical wear, and prevents frictional heat from affecting mechanical accuracy and causing failure. Furthermore, it can also prevent temporary deterioration of contact between the conductive member and the movable member due to vibrations caused by mechanical friction, resulting in temporary interruption of power supply or discharge between the conductive member and the movable member. This also eliminates abnormal wear and tear on the conductive members and movable members due to electrolysis. Therefore, it has a long life and
A power supply device capable of extremely stable power supply is obtained.

According to the second invention, since the conductive member and the wire electrode are connected not through mechanical contact but through the fluid held by magnetic force, stable power supply can be achieved without reducing the fluid. That is, power supply is not temporarily cut off due to poor contact due to vibration of the wire electrode, and abnormal wear and tear of the conductive member and the wire electrode due to discharge or electrolysis between the conductive member and the wire electrode is eliminated. In addition, since there is no electrical discharge at the power feeding part, the frequency of wire electrode breakage is extremely low, the maximum machining speed is increased by about 20% or more, and the wire electrode and power feeding part do not weld together, resulting in stable continuity. Automatic processing becomes possible. In addition, since deformation of the wire electrode is prevented and there is no consumption of the power supply section, semi-permanent use is possible, and a wire electrical discharge machining device capable of extremely stable continuous high-speed machining and continuous automatic machining is obtained.

[Brief explanation of the drawing]

Fig. 1 is a structural diagram showing a first embodiment of the first invention;
The figure is a structural diagram showing a second embodiment of the first invention, FIG. 3 is a structural diagram showing a third embodiment of the first invention, and FIG. 4 is a structural diagram showing a second embodiment of the first invention.
FIG. 5 is a structural diagram showing a second embodiment of the second invention; FIG. 6 is a structural diagram showing a third embodiment of the second invention. , FIG. 7 is a structural diagram of a conventional power supply device, and FIG. 8 is a structural diagram of a conventional power supply device for a wire electrical discharge machining apparatus. (3)...Electrifying power supply, (21)...Rotating member, (
27)... Conductive member, (28)... Permanent magnet, (2
9)...Magnetic fluid, (31)...Rotating shaft member,
(37)...Ring-shaped conductive member, (38)...Ring-shaped permanent magnet, (41)...Flat-shaped member, (47)
... Conductive member, (48) ... Permanent magnet, (51)
...wire electrode, (58) ...added enosul, (55
)... Power source for processing, (57) Ring-shaped conductive member, (57a)... Conductive member, (58)... Ring-shaped conductive member, (58a)... Permanent magnet, ( 60)・
... Electromagnetic coil, (61) ... DC power supply, (62) ...
··switch. In each figure, the same reference numerals indicate the same or corresponding parts. Agent Patent Attorney Muneharu Sasaki Fig. 1 31, Rotating shaft sound material 37, Ring-shaped conductive sleeve part Hayashi 38, Ring-shaped permanent hole E Fig. 2 55, Processing power source 57. Ring-shaped conductive sin material 58, ring-shaped permanent @ stone No. 4 figure 57a, 4 @ gender section 580, Eikyu stone No. 5 mark, electric stone coil 61, DC power supply 62, Sui tuna No. 6 Figure 7 Figure 8 Procedural amendment (voluntary)

Claims (3)

[Claims] (1) An electrically conductive member provided close to the movable member and connected to a power source, an electromagnetic induction means that applies a magnetic field to the electrically conductive member and generates magnetic force at a portion facing the movable member, and the movable member 1. A power supply device for a movable member, comprising: and a conductive magnetic fluid filled in an opposing portion of the conductive member. (2) The power supply device for a movable member according to claim 1, wherein the movable member is a wire electrode of a wire electrical discharge machining device. (3) The power supply device for a movable member according to claim 1 or 2, wherein a mixed fluid in which ferromagnetic fine particles are dispersed in a conductive fluid is used as the magnetic fluid.