JP2009166186A - Electric discharge machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric discharge machine including a collet chuck mechanism for making attachment/detachment of a collet holder easy to prevent a twist, and suppressing a cost. <P>SOLUTION: The collet holder 46 has a plurality of protrusions 46c, 46d and 46f each contacting with an inner peripheral surface of an attachment/detachment part 32c provided inside a spindle 32 and formed like a flange 46g, wherein an aperture between an outer peripheral surface of one 46c, 46d or 46f of the plurality of protrusions 46c, 46d and 46f and the inner peripheral surface is made to be smaller than the aperture between the outer and inner peripheral surfaces of the other protrusions 46c, 46d and 46f. Since this constitution secures a large aperture by first putting the protrusions 46c and 46d in the attachment/detachment part 32c and the aperture can be reduced in size by subsequently putting the protrusion 46f in the part 32c, attachment/detachment is made easy and the twist is prevented. The cost is suppressed since only the plurality of protrusions 46c, 46d and 46f are need to be formed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric discharge machine that includes a spindle, a collet holder, and an electrode, and processes the workpiece by intermittently discharging between the electrode and the workpiece.

Conventionally, the spindle is provided with a plurality of locking members (steel balls) in the hole provided in the peripheral wall near the lower end of the mounting hole, and the collet holder is provided with an annular groove on the upper side of the flange portion, and is engaged with the annular groove. An example of a technique for mounting a collet holder on a spindle so that a member fits is disclosed (see, for example, Patent Document 1).
JP 2002-301623 A

  When the collet holder is mounted on the spindle, the smaller the gap between the outer diameter of the collet holder and the inner diameter of the mounting hole of the spindle, the higher the adhesion and the less the rattling. However, as the gap becomes smaller, it becomes difficult to insert the collet holder into the mounting hole. Even if the collet holder is inserted into the mounting hole, if the axial centers of both the collet holder and the spindle do not match, the collet holder is likely to be twisted. Such drowning occurs either by a robot hand or by a manual operation. When wrinkling occurs, damage may occur to one or both of the outer peripheral surface of the collet holder and the inner peripheral surface of the mounting hole of the spindle.

  In order to easily attach and detach and prevent twisting, it is conceivable that the corresponding part of the collet holder and the spindle is a tapered surface. However, in order to improve the adhesion, it is necessary to precisely process the tapered surface, which increases the manufacturing cost of the collet holder and the spindle.

  The present invention has been made in view of these points, and it is an object of the present invention to provide an electric discharge machine equipped with a collet chuck mechanism that is easy to attach and detach the collet holder to prevent the collet holder and keeps the cost low. Objective.

(1) Means for solving the problem (hereinafter simply referred to as “solution means”) 1 is as described in claim 1.
According to the solution 1, the plurality of protrusions provided on the collet holder are formed in a flange shape, and each protrusion is respectively connected to the inner peripheral surface of the attaching / detaching part provided inside the spindle when attaching / detaching the collet holder. Can touch. The gap between the outer peripheral surface of one protrusion and the inner peripheral surface of the detachable portion is the outer peripheral surface of another protrusion (specifically, it is one or more protrusions, but preferably two protrusions). And smaller than the gap between the inner peripheral surface of the detachable portion. According to this configuration, since a large gap is ensured by first inserting the other protrusions into the attachment / detachment portion, attachment / detachment can be facilitated and dripping can be prevented. Later, by inserting one protrusion into the attachment / detachment portion, the gap can be reduced, adhesion can be improved, and rattling can be prevented. In addition, when removing the collet holder from the attaching / detaching portion, the operation and effect can be obtained in the same manner only by reversing the procedure. Since it is only necessary to process the collet holder to form a plurality of protrusions, the cost can be kept low.

(2) Solution 2 is as described in claim 2.
According to the solution means 2, at least the tip-side protrusion is provided with a tapered surface at the tip-side corner. According to this configuration, not only a large clearance is ensured, but also the collet holder is easily guided to the attaching / detaching portion of the spindle by the tapered surface. Therefore, the collet holder can be attached and detached more quickly.

(3) The solving means 3 is as described in claim 3.
According to the solution 3, the one protrusion and the other protrusion cooperate to engage with the locking member provided on the spindle. According to this structure, since one protrusion part and another protrusion part serve as the to-be-latched part engaged with a latching member, it is not necessary to provide a to-be-latched part separately. As described above, since the number of protruding portions (that is, protrusions and locked portions) to be formed in the collet holder can be reduced, the manufacturing cost of the collet holder can be reduced.

  According to the present invention, it is possible to easily attach and detach the collet holder to prevent the collet holder and to keep costs low.

  The best mode for carrying out the present invention will be described with reference to FIGS. Here, FIG. 1 is a front view showing a configuration example of the fine hole electric discharge machine. FIG. 2 is a partial cross-sectional view showing a partial configuration of the machining head. In FIG. 3, the structural example of a collet holder is represented with a front view. 4 shows a state before attachment, FIG. 5 shows a state during attachment, and FIG. 6 shows a state after attachment. In addition, directions such as up, down, left, and right are based on the descriptions in the corresponding drawings.

  First, a configuration example of a fine hole electric discharge machine will be described with reference to FIG. The fine hole electric discharge machine 10 is roughly divided into an electric discharge machine main body 12 and a machining control device 14. A configuration example of the electric discharge machine main body 12 will be described later. The processing control device 14 is a device that controls processing such as movement of the processing head 16 and processing by electric discharge, and includes an operation panel 28, a power source, and the like. The operation panel 28 inputs necessary data for moving the machining head 16, machining by electric discharge, etc., and gives control instructions.

  The electric discharge machine main body 12 is a device that processes a workpiece by intermittently discharging between the electrode 18 and the workpiece in accordance with a signal (including electric power) sent from the machining control device 14, and includes a machining head. 16, electrode 18, processing tank 20, mount 22, intermediate guide 24, bracket 26, and the like. A configuration example of the processing head 16 will be described later. The electrode 18 is attached to a collet holder 46 (see FIGS. 2 and 3). The electrode 18 is prevented from shaking by the intermediate guide 24 and is guided by an electrode guide (not shown) attached to the bracket 26. A processing tank 20 is installed above the gantry 22, and a workpiece is placed in the processing tank 20.

  The machining head 16 is a part that performs electric discharge machining, and a partial configuration example is shown in FIG. The machining head 16 is configured to be able to control the movement in the Z-axis direction (that is, the vertical direction), and mainly includes the rotating union 30, the spindle 32, the bearing block 38, the energizing ring 40, the plug 42, the locking member 44, and the collet holder 46. , Sealing block 48, servo motor 50, and the like.

  The rotating union 30 supplies the machining fluid at a predetermined pressure toward a hollow passage 32 a provided in the spindle 32. The spindle 32 is rotatably supported by a bearing block 38. A pulley 34 is fixed to the spindle 32, and a pulley 52 is fixed to the main shaft 50 a of the servo motor 50. A timing belt 36 is stretched between the pulley 34 and the pulley 52, and the spindle 32 is rotated by driving the servo motor 50 to rotate. The servo motor 50 is fixed to the bearing block 38 via the base 54. The servo motor 50, the timing belt 36, and the like correspond to a drive mechanism.

  The spindle 32 has a passage 32b and an attaching / detaching portion 32c together with a hollow passage 32a provided in a large part. The passage 32b is formed wider than the passage 32a, and a cylindrical sealing block 48 is provided inside. The detachable portion 32c is formed at the lower end portion (lower side of the drawing) of the spindle 32, and is provided with a locking member 44 composed of one or a plurality of steel balls formed in a substantially perfect circle. A collet holder 46 to be described later is attached to and detached from the attaching / detaching portion 32c. A mechanism for attaching / detaching the collet holder 46 to / from the attaching / detaching portion 32c of the spindle 32 is referred to as a “collet chuck mechanism”.

  The above-described sealing block 48 is a member that guides the machining fluid flowing through the passage 32a to the passage 46h (see FIG. 3) of the collet holder 46. The sealing block 48 is formed with a long groove-shaped restricting groove 48a, and is fastened so that the set screw 48b is inserted into the restricting groove 48a. Thus, the sealing block 48 moves within the restriction groove 48a, that is, within a predetermined range in accordance with the flow-down pressure of the machining liquid (in the vertical direction in the example of FIG. 2).

  Furthermore, the spindle 32 is made of a material (for example, metal) that can be energized, and an energization ring 40 is provided so as to be in contact with the outer peripheral surface thereof. The energizing ring 40 is provided with a plug 42 in contact therewith. Therefore, the electric power for discharge sent from the machining control device 14 is transmitted to the spindle 32 through the plug 42 and the energization ring 40.

  Next, a configuration example of the collet holder 46 will be described with reference to FIG. The collet holder 46 includes a packing 46a, protrusions 46c, 46d, 46f, a flange 46g, and the like. As with the spindle 32, the collet holder 46 is provided with a hollow passage 46h, and a packing 46a is provided at the end on the tip side (upper side in the drawing). The two flanges 46g are used for gripping when the collet holder 46 is exchanged.

The protrusions 46c, 46d, and 46f can be in contact with the inner peripheral surface of the detachable portion 32c, and are formed in a flange shape. That is, the shape is similar to that of the flange 46g, but the outer diameter is smaller than the flange 46g and the thickness is increased. The interval between the protruding portion 46c and the protruding portion 46d is made larger than the interval between the protruding portion 46d and the protruding portion 46f. A tapered surface 46b is formed at the corner on the tip side (upper side of the drawing) of the protrusion 46c, and a taper surface 46e is formed at the corner on the tip side of the protrusion 46f. The protrusion 46c and the protrusion 46d are formed with an outer diameter φ4, and the protrusion 46f is formed with an outer diameter φ2 (where φ2> φ4). Since the inner peripheral surface of the detachable portion 32c is formed with a constant inner diameter φ6 (see FIG. 4), the gap between the outer peripheral surface of the protrusion 46f and the inner peripheral surface of the detachable portion 32c (hereinafter simply referred to as a gap Δ4). Is smaller than the gap between the outer peripheral surfaces of the protrusions 46c and 46d and the inner peripheral surface of the detachable portion 32c (hereinafter simply referred to as a gap Δ2). That is, Δ2> Δ4.
In the configuration of this example, the protrusion 46 f corresponds to “one protrusion”, and the protrusions 46 c and 46 d correspond to “other protrusions”.

An example of attaching / detaching the collet holder 46 configured as described above to / from the attaching / detaching portion 32c of the spindle 32 will be described with reference to FIGS.
First, in FIG. 4 showing the state before attachment, the collet holder 46 starts to be inserted from the distal end side toward the attaching / detaching portion 32c in the direction of the arrow D2. Since the taper surface 46b is formed at the tip side portion of the protrusion 46c, it can be easily put into the detachable portion 32c without causing twisting. When the insertion of the collet holder 46 is continued, the protruding portion 46c and the protruding portion 46d are in the detachable portion 32c, which is shown in FIG. As described above, since the protrusion 46c and the protrusion 46d are formed with substantially the same outer diameter φ4, the gap Δ2 is substantially the same as the inner peripheral surface of the detachable portion 32c. Thus, when the protrusion 46c and the protrusion 46d come into contact with the inner peripheral surface of the detachable portion 32c, straightness is obtained when the collet holder 46 is attached.

Further, when the insertion of the collet holder 46 is continued, a tapered surface 46e is also formed on the tip side of the protrusion 46f when the protrusion 46f enters the detachable part 32c. Therefore, it is easy to put in the attaching / detaching portion 32c without causing the twist. Then, the locking member 44 is locked so as to be positioned between the protruding portion 46d and the protruding portion 46f. That is, one protrusion 46f and the other protrusion 46d cooperate to engage with the locking member 44. Thus, the attachment of the collet holder 46 to the attaching / detaching portion 32c is completed, and this state is shown in FIG.
In addition, the collet holder 46 can be removed by extracting the collet holder 46 from the attachment / detachment part 32c in the direction of the arrow D4 in the reverse procedure of the attachment described above.

According to the embodiment described above, the following effects can be obtained.
(1) The gap Δ4 between the outer peripheral surface of one protrusion 46f and the inner peripheral surface of the detachable portion 32c is smaller than the gap Δ2 between the outer peripheral surfaces of the other protrusions 46c and 46d and the inner peripheral surface of the detachable portion 32c. It became the composition which becomes. According to this configuration, since the gap is secured by inserting the other protrusions 46c and 46d into the attachment / detachment part 32c first, the attachment / detachment can be facilitated to prevent dripping, and the one protrusion 46f can be attached / detached. Straightness is provided to facilitate entry into the portion 32c. Later, by inserting one protrusion 46f into the attaching / detaching portion 32c, the gap can be reduced, and the adhesiveness can be improved to prevent rattling. When removing from the attaching / detaching part 32c, the same effect can be obtained only by reversing the procedure. Since it is only necessary to process the collet holder 46 so as to form a plurality of protrusions 46c, 46d, and 46f, the cost can be reduced.

(2) The tapered surface 46b is provided at the tip side corner of the projection 46c, and the tapered surface 46e is provided at the tip side corner of the projection 46f (see FIG. 3). According to this configuration, not only a large clearance is ensured, but also the collet holder 46 is easily guided to the detachable portion 32c by the tapered surfaces 46b and 46e. Therefore, the collet holder 46 can be attached and detached more quickly.

(3) One projecting portion 46f and another projecting portion 46d cooperate to engage with the locking member 44 provided on the spindle 32 (see FIG. 6). According to this configuration, since one projection 46f and the other projection 46d serve as a locked portion that engages with the locking member 44, it is not necessary to separately provide the locked portion. As described above, since the number of protruding portions (that is, protrusions and locked portions) to be formed on the collet holder 46 can be reduced, the manufacturing cost of the collet holder 46 can be reduced.

[Other Embodiments]
Although the best mode for carrying out the present invention has been described above, the present invention is not limited to this mode. In other words, various forms can be implemented without departing from the scope of the present invention. For example, the following forms may be realized.

(1) In the above-described embodiment, the present invention is applied to the fine hole electric discharge machine 10 (see FIG. 1). It can replace with this form and can be applied also to other electric discharge machines except fine hole electric discharge machine 10, and a cutting machine provided with a collet chuck mechanism. In the case of a cutting machine, a cutting tool provided with a plurality of protrusions may be used instead of the collet holder 46. Even when applied to these processing machines, the same effects as those of the above-described embodiment can be obtained.

(2) In the above-described embodiment, the collet holder 46 includes the three protrusions 46c, 46d, and 46f (see FIG. 3). However, the collet holder 46 may include four or more protrusions. The protrusion 46c and the protrusion 46d are formed with an outer diameter φ4, and the protrusion 46f is formed with an outer diameter φ2 (where φ2> φ4) (see FIG. 3). May be larger than φ4 and smaller than φ2. Thus, even when the number of protrusions and the outer diameter are changed, the same effect as that of the above-described embodiment can be obtained.

(3) In the above-described embodiment, the front end side corner of the protrusion 46d is simply chamfered (see FIG. 3). However, as with the protrusion 46c and the protrusion 46f, a tapered surface is provided. Also good. In this way, the protruding portion 46d can be smoothly inserted after the protruding portion 46c without falling into the detachable portion 32c.

(4) In the above-described embodiment, the locking member 44 (steel ball) is used as an object with which the protrusion 46f and the protrusion 46d are engaged in cooperation (see FIGS. 2 and 6). Instead of this form, another locking member that can be engaged between the protruding portion 46f and the protruding portion 46d may be used. Even when other locking members are used, the number of protrusions to be formed on the collet holder 46 can be reduced, so that the manufacturing cost of the collet holder 46 can be reduced.

It is a front view showing the structural example of a fine hole electric discharge machine. It is a fragmentary sectional view showing partial composition of a processing head. It is a front view showing the example of composition of a collet holder. It is a figure explaining the state before attachment. It is a figure explaining the state in the middle of attachment. It is a figure explaining the state after attachment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Thin hole electric discharge machine 12 Electric discharge machine main body 14 Processing control apparatus 16 Processing head 18 Electrode 20 Processing tank 22 Base 24 Intermediate guide 26 Bracket 28 Operation panel 30 Rotation union 32 Spindle 32a, 32b Passage 32c Attachment / detachment part (Collet chuck mechanism)
34 Pulley 36 Timing belt 38 Bearing block 40 Energizing ring 42 Plug 44 Locking member (steel ball)
46 Collet holder (Collet chuck mechanism)
46a Packing 46b, 46e Tapered surface 46c, 46d, 46f Projection 46g Flange 46h Passage 48 Sealing block 48a Restriction groove 48b Set screw 50 Servo motor 50a Main shaft 52 Pulley 54 Base

Claims (3)

A spindle that can be rotated by a drive mechanism, a collet holder that can be attached to and detached from the tip of the spindle, and an electrode that is attached to the collet holder. The electrode is intermittently discharged between the electrode and the workpiece. An electric discharge machine for processing a workpiece,
The collet holder has a plurality of protrusions that can be in contact with the inner peripheral surface of the detachable part provided inside the spindle and are formed in a flange shape,
An electric discharge machine configured such that a gap between an outer peripheral surface of one of the plurality of protrusions and the inner peripheral surface is smaller than a gap between the outer peripheral surface of another protrusion and the inner peripheral surface. The electric discharge machine according to claim 1,
An electric discharge machine having a configuration in which a taper surface is provided at a corner on the tip side, including at least a projection on the tip side among the plurality of projections. An electric discharge machine according to claim 1 or 2,
One protrusion and the other protrusion are configured to be configured to engage with a locking member provided on the spindle when the collet holder is mounted on the tip of the spindle.

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