JP2832398B2 - Wire cut electric discharge machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire electric discharge machine, and more particularly to a wire electric discharge machine suitable for positioning between a wire electrode and a workpiece.

[0002]

2. Description of the Related Art In a conventional wire-cut electric discharge machine, when positioning between a wire electrode and a workpiece, the wire electrode is driven while the wire electrode travels from a feed side to a pickup side. And a relative movement for bringing the end surface of the workpiece into contact with the workpiece. The contact between the two is determined by establishing an electrical conduction state, and the relative positional relationship between the two is detected. .

[0003]

In order to perform such a positioning operation, it is necessary to apply a tension higher than a certain value to the wire electrode. In such a powder brake, the tension can be applied only in a state where the wire electrode is running, so that it is necessary to keep the wire electrode running at the time of positioning. However, if the positioning is performed while the wire electrode is running, the fine vibration generated in the wire electrode due to the running causes
There is a problem that accurate positioning cannot be performed. An object of the present invention is therefore to provide an improved wire-cut electric discharge machine which can solve the above-mentioned problems in the prior art.

[0004]

According to the present invention, a variable torque clutch device for applying a predetermined tension to a wire electrode is provided on the wire electrode discharge side of the wire cut electric discharge machine according to the present invention. One of the rotating shafts of the variable torque clutch device is connected to a tension roller for sending out a wire electrode, and the other rotating shaft of the variable torque clutch device is connected to a motor that can rotate in a direction opposite to a direction in which the wire electrode is sent out. Are linked. The other rotating shaft is further provided with a brake device for locking the rotation of the other rotating shaft when the wire electrode is in a running state for machining. On the other hand, a wire electrode pulling device is provided on the wire electrode pulling side of the wire cut electric discharge machine, and this wire electrode pulling device prevents the wire electrode from running toward the wire electrode sending side. For preventing reverse rotation. This reverse rotation prevention device is provided on the wire electrode take-up side by the wire tension when the motor is operated and the wire electrode is pulled by the tension roller in a direction opposite to the wire electrode traveling direction for processing. The wire electrode pulling device may be a brake means for preventing the wire electrode from running toward the wire electrode sending side. The motor rotates in the opposite direction, and the wire electrode is driven to run in the direction opposite to the running direction for machining, so that the wire electrode has a tension when the wire electrode is in the running state for machining. Preferably, it is configured so that substantially equal tension is applied.

[0005]

When performing electric discharge machining, the other rotating shaft of the torque variable clutch device is locked by the brake device, and a tension corresponding to the torque adjustment value at that time is applied to the wire electrode. On the other hand, when performing positioning, the torque variable clutch device releases the locked state of the other rotating shaft by the brake device, and operates the motor so that the wire electrode travels in a direction opposite to the traveling direction for machining. Is driven to rotate. At this time, the wire electrode does not travel toward the wire electrode delivery side due to the reverse rotation preventing device irrespective of the above-described operation of the torque variable clutch device. Therefore, a predetermined tension is applied to the wire electrode in the traveling stop state, and the wire electrode is in a state suitable for positioning.
By setting the predetermined tension to a tension substantially equal to the tension when the wire electrode is in a running state for processing, extremely good positioning can be performed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of a wire-cut electric discharge machine according to the present invention. In the wire-cut electric discharge machine 1, a wire electrode feeding side is indicated by a symbol A, and a wire electrode pick-up side is indicated by a symbol B. It is shown.

The wire electrode 3 wound around the wire bobbin 2 provided on the wire electrode sending side A passes through the cylindrical roller 4 and the guide 5 and enters the tension roller 6 for sending the wire electrode. After passing through, it enters the tension roller 6 again, and then is sent out. Here, reference numeral 8 denotes a pinch roller, and the wire electrode 3 is pressed against the tension roller 6 by the pinch roller 8.

The wire electrode 3 taken out of the tension roller 6 passes through the felt 9 and the pulley 10, and is guided by the upper wire guide 11 and the lower wire guide, and the pulley 13 and the pipe 14 provided on the lower arm C are provided. Through the suction unit 15.

[0010] A pair of feed rollers 16, 16 are provided on the outlet side of the suction unit 15, and the wire electrode 3 is picked up by the pair of feed rollers 16, 16 and discharged into the wire box 17.

Referring to FIG. 2, a variable torque clutch device 20 connected to the tension roller 6 of FIG. 1 is shown in detail in cross section. Variable torque clutch device 2
0 is the output shaft 21 to which the tension roller 6 is fixed.
The output shaft 21 is rotatably supported by a bearing device 22 fixed to the frame F by a suitable means such as a bolt. A powder clutch 23 that is slip-controlled by a control circuit (not shown) is provided at a rear end of the bearing device 22. An output shaft 24 of the powder clutch 23 is connected to the output shaft 21 by a joint member 25.

On the other hand, the input shaft 26 of the powder clutch 23
The output shaft 29 of the motor 28 fixed integrally with the powder clutch 23 by the bracket 27 and the pulley 3
The belt 28 is belt-coupled to the tension roller 6 via the powder clutch 23.

As can be seen from the above description, the rotational torque of the tension roller 6 is adjusted by the electric energy applied to the powder clutch 23.

The motor 28 is rotatable in the forward and reverse directions, and causes the wire electrode 3 to travel toward the wire electrode pick-up side B for electric discharge machining of the workpiece W disposed between the upper and lower wire guides 11 and 12. In this case, the output shaft 21 is X
It is rotated in the direction. However, as will be described later, when the tension of the wire electrode 3 is stopped by stopping the travel of the wire electrode 3 for detecting the position, the motor 28 rotates the output shaft 21 in the opposite Y direction.

In FIG. 1, the workpiece W is an NC.
The NC device is moved relative to the wire electrode 3 by a moving device. However, the NC moving device is a known device, and therefore, the configuration for controlling the relative movement is not shown in FIG. A pulse voltage for electric discharge machining is applied between the workpiece W and the wire electrode 3,
The electrical configuration for this is also known, and is not shown.

Referring to FIG. 3, a pair of feed rollers 1
A wire electrode tensioning device 40 comprising 6, 16 is shown in cross section.

One feed roller 16 is rotatably mounted on a fixed shaft 42 provided on a frame 41,
The other feed roller 16 is fixed to an output shaft 44 of a one-way clutch 43 fixed to the frame 41 by appropriate means such as bolting, and the other feed roller 16 is configured to rotate integrally with the output shaft 44. is there.

Engagement spur gears 45, 46 are fixed to the feed rollers 16, 16, respectively.
5, 46 are engaged. As a result, the rotational force of the output shaft 44 is transmitted to one of the feed rollers 16 via the engagement spur gears 45 and 46.

The wire electrode 3 is fed between the pair of feed rollers 16, 16.
The one-way clutch 4 is rotated so that a required tensile force can be applied to the wire electrode 3.
A motor 49 for applying this rotational force is fixed to the extension 48 of the third frame 47.

The output shaft 50 of the motor 49 and the input shaft 51 of the one-way clutch 43 are connected to a pair of bevel gears 52,5.
3 and can apply the rotational force of the motor 49 to the input shaft 51 of the one-way clutch 43.

The motor 49 rotates the input shaft 51 in a direction in which the rotation of the one-way clutch 43 can be transmitted.
6 and the wire electrode 3 can be pulled toward the wire box 17.

When the driving of the motor 49 is stopped, the pair of rollers 16 cannot rotate so as to return the wire electrode 3 to the opposite direction to the wire box 17 due to the reverse rotation preventing function of the one-way clutch 43. When the electrode 3 is pulled toward the wire electrode sending side, the wire electrode 3 can be firmly gripped against this pulling force.

Next, the operation of the wire electric discharge machine shown in FIG. 1 will be described.

After the wire electrode 3 is wired by appropriate means as shown in the figure, the rotation of the motor 49 is stopped, the pulling operation of the wire electrode 3 by the wire electrode pulling device 40 is stopped, and the motor 28 is rotated in the reverse direction. The rotation direction of the tension roller 6 by the torque variable clutch device 20 is set to the Y direction.

As a result, on the wire electrode take-up side B, the wire electrode 3 is gripped by the wire electrode pulling device 40 to be in a fixed state, while the wire electrode delivery side A is held.
In the above, the wire electrode 3 is pulled in a direction opposite to the feeding direction, and the wire electrode 3 is loaded with a tension substantially equal to the tension in the traveling state for machining while the traveling state is stopped. State.

In this state, the detection of the relative positional relationship between the wire electrode 3 and the workpiece W is executed by a known method by an NC controller (not shown). In this case, since the wire electrode 3 does not travel, no fine vibration or the like occurs, and a tension substantially equal to the tension in the traveling state for processing is applied to the wire electrode 3. Highly accurate position detection can be performed.

When the position detection is completed in this manner, the motor 28 is rotated in the forward direction, and the tension roller 6 is rotated in the X direction, so that the wire electrode 3 is sent out toward the wire electrode pickup side B and Then, the motor 49 is rotated to cause the pair of feed rollers 16, 16 to perform the operation of drawing the wire electrode 3.

As a result, the wire electrode 3 starts running from the wire electrode sending side A to the wire electrode pickup side B while a required tension is being applied, and the electric discharge machining of the workpiece W can be performed. .

In the above embodiment, the one-way clutch 43 is used to stop the running of the wire electrode 3 gripped by the pair of feed rollers 16, 16 so that the wire electrode 3 can be fixed. Although the tension device 40 is configured, an electromagnetic brake or the like may be provided on the motor 49 and the rotation shaft of the motor 49 may be locked by the electromagnetic brake or the like. In this case, a one-way clutch is not required.

Further, the wire electrode pulling device 40 is provided with the structure shown in FIG.
As shown in FIG. 3, the rotational force from the motor 49 is transmitted to the feed roller 1 via the belt transmission mechanism 61 and the torque limiter 62.
Alternatively, a one-way crack may not be required.

[0031]

According to the present invention, in a wire electric discharge machine having a brake device including a tension roller or the like on a wire electrode sending side, a wire electrode is required even when traveling of the wire electrode is stopped. Therefore, the relative positional relationship between the wire electrode and the workpiece can be checked very accurately, and accurate electric discharge machining can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a wire cut electric discharge machine according to the present invention.

FIG. 2 is a cross-sectional view of a variable torque clutch device for driving the tension roller of FIG.

FIG. 3 is a sectional view of a wire electrode pulling device including the feed roller of FIG. 1;

FIG. 4 is a sectional view showing another embodiment of the wire electrode pulling device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire cut electric discharge machine 3 Wire electrode 6 Tension roller 16 Feed roller 20 Torque variable clutch device 28 Motor 40 Wire electrode tension device 43 One-way clutch W Workpiece

Claims (2)

(57) [Claims] In a wire-cut electric discharge machine, one rotating shaft is connected to a tension roller and the other rotating shaft is connected to a motor that can rotate in a direction opposite to a direction in which a wire electrode is sent out, on a wire electrode sending side. A torque variable clutch device, and a brake device for locking the rotation of the other rotation shaft when the wire electrode is in a running state for machining, and the wire electrode taking-in side is provided with the brake device. A wire-cut electric discharge machine comprising a wire electrode pulling device provided with a reverse rotation preventing means for preventing the wire electrode from traveling to the wire electrode sending-out side. 2. The motor rotates in the opposite direction, and the wire electrode is driven to run in a direction opposite to a running direction for processing, so that the wire electrode is attached to the wire electrode for processing. 2. The wire-cut electric discharge machine according to claim 1, wherein a tension substantially equal to the tension when the vehicle is in the running state is applied.