JPH10225823A - Chuck device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To securely grasp an electrode of an ultra-thin diameter without crushing it. SOLUTION: In this chuck device, three chuck containing chambers 13 are radially formed inside a holder 10, and chuck jaws 15A, 15B, 15C are contained inside them to be radially movable. Protruded parts 18 are disposed like comb- teeth at a constant pitch on facing surfaces of the chuck jaws 15A, 15B, 15C, where their phase is deflected for the respective chuck jaws 15A, 15B, 15C, so the chuck jaws 15A, 15B, 15C can get close to each other while abutting surfaces 19 formed on tips of the protruded parts 18 are overlapped with each other. The abutting surfaces of the respective chuck jaws 15A, 15B, 15C can therefore form insertion space in a circumferential direction almost without gap, thereby misalignment of an electrode can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck device.

[0002]

2. Description of the Related Art For example, a machining electrode provided in an electric discharge machine is held by a chuck device incorporated in an electrode holder. More specifically, it has a structure as shown in FIG. 6, and the chuck device has three chuck jaws 101 incorporated in a holder 100. Each chuck jaw 101 is arranged at a radial position, and always secures a space (insertion space 103) between the distal ends thereof so that the electrode 102 can be inserted. The tips of the chuck jaws 101 approach each other to narrow the insertion space 103 and hold the electrode 102.

[0003]

By the way, drilling has been conventionally performed based on electric discharge machining. Recently, however, precision drilling with an extremely small diameter (0.2 to 1 mm) has been required. It has become Of course, in order to enable such ultra-fine processing, the electrodes also have a small diameter.
However, when the micro-diameter electrode is held by the above-described chucking method, the following inconvenience occurs.

That is, since there is a gap between the three chuck jaws 101, there is a concern that the electrode 102 may be misaligned and a part of the electrode may enter the gap. In particular, when the outer diameter of the electrode is small, the tip of each chuck jaw becomes sharp, and it is practically impossible to form a guide for concentricity generally adopted here. Become. Therefore, the electrode is likely to be chucked with the core shifted, in which case the electrode may be crushed.

[0005] Further, another problem was pointed out. In the prior art, chucking is performed by tightening the chuck jaws, that is, specifically, by screwing a nut member for tightening arranged on the outer peripheral side of the chuck jaw. Depends on the tightening torque. However, since the tightening operation is performed manually, the torque is not stable, and problems such as crushing of the electrode due to insufficient tightening or conversely excessive tightening cannot be avoided.

[0006] The present invention has been devised in view of the above-mentioned conventional problems, and an object of the present invention is to ensure that even an extremely small-diameter gripping object can be gripped. Another object is to eliminate excessive tightening.

[0007]

According to the first aspect of the present invention, a plurality of rod-shaped objects are provided at radial positions around an insertion space into which an object to be gripped is inserted. A chuck device in which chucking members are disposed, and the chucking members can be gripped and released by being displaced in a radial direction. An abutting surface is formed on the outer peripheral surface of the object, and each abutting surface is arranged in the axial direction for each chucking member so that the abutting surfaces can surround the object to be grasped from the circumferential direction while overlapping the abutting surfaces. It is characterized by being arranged offset.

According to a second aspect of the present invention, each of the chucking members is provided with a projection having the contact surface in a comb shape, and the projections are shifted in the axial direction for each chucking member. It is characterized by being arranged in a position.

Further, according to a third aspect of the present invention, an axially movable sleeve is disposed outside each of the chucking members, and an axial direction of the sleeve is provided between the sleeve and each of the chucking members. The chucking member moves the chucking member in the direction of gripping and releasing the object to be gripped along with the movement of the gripping object, and a locking means capable of restricting a movement stroke thereof is interposed. Is what you do.

[0010]

According to the first aspect of the present invention, when chucking the object to be gripped, the object to be gripped is inserted into the insertion space held between the tips of the chucking members.
At this time, since the contact surfaces of the chucking members are displaced in the axial direction, they can overlap without interfering with each other, and thus surround the object to be grasped from the circumferential direction with almost no gap. Then, when each chucking member moves in the radial direction as it is, the space surrounded by each contact surface is gradually narrowed, whereby the object to be gripped is clamped.

According to the second aspect of the present invention, since the protrusion of each chucking member is formed in a comb shape, it is possible to hold the object to be gripped while avoiding interference between the chucking members.

According to the third aspect of the present invention, when the sleeve is moved in a predetermined direction along the axial direction after the object to be gripped is inserted into the insertion space, the locking means moves the chucking members toward each other. It moves and clamps the object to be grasped. At this time, since the locking means regulates the movement stroke of each chucking member, an excessive tightening force does not act.

[0013]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIG. However, also in the present embodiment, a description will be given of an example of a chuck device for an electric discharge machining electrode. The chuck device is mounted on an electrode holder H of an electric discharge machine, and electric discharge machining is performed in a state where the electrodes and the workpiece are immersed in a coolant liquid tank (also not shown).

In FIG. 1, reference numeral 1 denotes a cylindrical casing, and a housing hole 2 is formed along the axis from the right end in the figure (the side to be mounted on the electrode holder) to an intermediate depth position. From there, it continues to the electrode holding hole 4 via the small diameter portion 3. First, a sealing member 5 made of oil-resistant rubber is fitted into the accommodation hole 2 up to the boundary with the small-diameter portion 3, and an insertion member 6 is screwed in such a manner as to abut against the sealing member 5.

The right end side of the housing hole 2 is a coolant inlet 7, and a passage 8 for passing the coolant is inserted through the insertion member 6 along the axis.
A through hole 9 penetrates through the center of the seal member 5, and an electrode D (formed in a pipe shape), which will be described later, penetrates through the through hole 9 to reach the distal end of the passage member 8 in the insertion member 6. I'm stuck. The coolant is for cooling the chuck device, and is poured into the above-mentioned coolant tank (not shown) through the inside of the electrode D.

The electrode holding hole 4 is formed to have a larger diameter than the receiving hole 2 and has a cylindrically shaped holder 1.
0 is screwed into one end. A sealing member 11 is concentrically attached to one end of the holder 10 by screwing, and a shaft hole 12 for loosely inserting the electrode D penetrates the center of the sealing member 11 along the axis. ing. Further, on the other end side of the holder 10, three chuck accommodating chambers 13 and a holding lid accommodating chamber 14 are formed.

Each of the chuck accommodating chambers 13 is formed by radially piercing radial positions of the wall surface from the center hole of the holder 10 at equal angular intervals, and each has a chuck jaw 15A, B, C is accommodated so as to be movable in the radial direction. And each chuck jaw 15A,
B and C are the holding lids 1 screwed into the holding lid housing chamber 14.
6 to prevent the tip from slipping off. An insertion hole 17 for the electrode D is formed at the center of the holding lid 16, and the tip of the insertion hole 17 is open in a trumpet shape for smooth insertion.

As shown in FIGS. 2 and 3, each of the chuck jaws 15A, 15B and 15C is formed in a shape that can be fitted to the chuck accommodating chamber 13, and a plurality of projections 18 are long on the surfaces facing each other. Each is provided along the length direction. The tip of each protrusion 18 is formed in an arc shape such that the center expands,
The edge forms a contact surface 19 that can contact the outer peripheral surface of the electrode D.

By the way, each of the chuck jaws 15A, 15B,
The projections 18 of C are arranged at regular intervals, and the projections 18 are arranged with a phase shift by the thickness of each projection 18 for each of the chuck jaws 15A, 15B, 15C. Even when the chuck jaws 15A, B, and C approach the center, the projections 18, that is, the contact surfaces 19 can overlap without interference. Further, both ends of each of the chuck jaws 15A, 15B, and 15C are configured to protrude from the above-described chuck accommodating chamber 13, and a groove 28 is formed on each of the protruding end surfaces, so that an O-ring serves as a seal. 20 is fitted. Due to the shape retaining force of the O-ring 20 itself, each of the chuck jaws 15A, 15B, and 15C is in a released state before the electrode D is inserted as shown in FIG.
It is urged radially outward until the insertion space 21 of the electrode D is held therebetween. However, even in this released state, the contact surfaces 19 of the chuck jaws 15A, 15B and 15C
Is a closed space with almost no gap in the circumferential direction in plan view.

On the other hand, a total of six lateral holes 22A and 22B are formed in the side surface of the holder 10 corresponding to the chuck jaws 15A, 15B and 15C.
The lateral holes 22A and 22B, which are paired in the axial direction, have a larger diameter at the tip end and a smaller diameter at the far end. The corresponding large and small balls 23A and 23B are accommodated therein so that they can enter and leave freely, and the large-diameter ball 23A side projects more from the holder 10.

A sleeve 24 for locking and unlocking the electrode D is fitted on the outer peripheral surface from the casing 1 to the holder 10 so as to be movable in the axial direction. A spring 25 is interposed between the sleeve 24 and the casing 1 inside the sleeve 24, and urges the entire sleeve 24 to move to the distal end side. However, a stopper edge 26 projects inward at the tip of the sleeve 24, and this
The forward position is regulated by engaging with the outer peripheral edge of the. Further, the inner surface of the sleeve 24 is formed with a tapered surface 27 which expands toward the distal end side, whereby the chuck jaws 15A, B, and C can be moved in the radial direction. Thus, when the sleeve 24 moves to the tip side, the large and small balls 23A,
B can move the entire chuck jaws 15A, B, and C in the radial direction, but since the advance position of the sleeve 24 is defined, excessive tightening of the chuck jaws 15A, B, and C is performed. Never.

This embodiment is configured as described above. Next, an operation for gripping the electrode D will be described. First, the sleeve 24 is retracted against the spring force of the spring 25. In this state, each chuck jaw 1 is pressed through the insertion hole 17 of the holding lid 16 while holding down the electrode D.
Push into the insertion space 21 between 5A, B and C. As described above, before the electrode D is inserted, each chuck jaw 15A,
Since there is a slight gap between the contact surfaces 19 of B and C, the electrode D can be inserted smoothly. The electrode D passes through the shaft hole 12 of the sealing member 11, the small-diameter portion 3, and the through hole 9 of the sealing member 5, and protrudes into the end of the passage 8 of the insertion member 6.

When the electrode D is inserted, the space surrounded by the contact surfaces 19 of the chuck jaws 15A, 15B and 15C, that is, the insertion space 21 is surrounded without any gap in the circumferential direction. The electrode D does not enter the gap and cause galling.

When the sleeve 24 is released after the insertion of the electrode D, the sleeve 24 returns to the forward position by the spring force of the spring 25. Since the tapered surface 27 pushes the balls 23A and 23B into the lateral holes 22A and 22B with the forward movement, the chuck jaws 15A, 15B and 15C do not tilt in the corresponding chuck accommodating chambers 13 without tilting. The whole moves in the direction approaching each other along the radial direction. As a result, the insertion space 21 surrounded by the contact surfaces 19 of the chuck jaws 15A, 15B, 15C is gradually narrowed, so that the electrode D is gripped.

Thus, the electrode D and the object to be drilled are immersed in the coolant liquid in the coolant tank, and in this state, the hole is drilled by electric discharge machining. During this time, the coolant flowing from the inlet 7 of the casing 1 continues to flow into the coolant tank through the electrode D, so that the chuck device itself is also cooled.

As described above, according to this embodiment, by arranging the projections 18 of the chuck jaws 15A, B, and C out of phase, the respective contact surfaces 19 can be overlapped. As a result, the electrode D insertion space 21 having no gap in the circumferential direction can be secured. For this reason, the narrowing down is not performed while the electrode D is misaligned, so that damage to the electrode D can be eliminated. This is particularly effective in the case of a small-diameter gripping target object.

Further, the locking and unlocking of the electrode D can be performed only by the operation of retracting or returning the sleeve 24 in the axial direction, so that the operability is excellent and the approach positions of the chuck jaws 15A, B, C are improved. Is also regulated, and the electrode D
There is no need to worry about crushing.

The present invention can be variously modified,
The following modifications are also included in the technical scope of the present invention.

In this embodiment, the case where the electrode D is gripped by the three chuck jaws 15A, 15B, 15C is shown, but the number is not limited. Further, the present invention is not limited to a chuck device for an electrode for electric discharge machining, but can be widely applied to chucks in general.

Although the coolant passage 8 is formed in the electrode D, such a passage 8 can be omitted unless it is particularly necessary to cool the chuck device.

Each of the chuck jaws 15A, 15B, 15C
In the present embodiment, the sleeve 24 is used as the tightening means, and one-touch locking and unlocking is enabled by utilizing the reciprocating operation in the axial direction. Operation may be used. Of course, in this case, too,
It is necessary to prevent the object to be gripped from being excessively tightened.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a chuck device in a state where an electrode is held.

FIG. 2 is a perspective view showing each chuck jaw.

FIG. 3 is a plan sectional view showing a chucking state.

FIG. 4 is a plan sectional view showing a released state.

FIG. 5 is a side sectional view in a state where an electrode is removed.

FIG. 6 is a plan sectional view showing a conventional chuck device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Casing 10 ... Holder 15A, B, C ... Chuck jaw 18 ... Protrusion 19 ... Contact surface 21 ... Insert space 23A, B ... Ball 24 ... Sleeve 25 ... Spring 27 ... Tapered surface D ... Electrode (object to be gripped)

Claims (3)

[Claims] 1. A plurality of chucking members are arranged at radial positions centered on an insertion space into which a gripping object formed in a rod-shape is inserted, and these chucking members are displaced in a radial direction to perform the gripping. A chuck device capable of gripping and releasing an object, wherein a contact surface capable of contacting an outer peripheral surface of the object to be gripped is formed at a tip of each of the chucking members, and The chuck device according to claim 1, wherein the contact surfaces are shifted in the axial direction for each of the chucking members so that the grasping object can be surrounded from the circumferential direction while overlapping the contact surfaces. 2. Each of the chucking members is provided with a protrusion having the contact surface in a comb-like shape, and the protrusions are arranged to be shifted in the axial direction for each chucking member. The chuck device according to claim 1, wherein: 3. An axially movable sleeve is disposed outside each of the chucking members, and between the sleeve and each of the chucking members, along with the axial movement of the sleeve. 3. A locking means for moving each of the chucking members in a direction in which the object to be gripped is gripped and released and in which a movement stroke thereof can be restricted is interposed. The chuck device as described in the above.