JP2001328014A - Chuck - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly accurate chuck for always gripping a round material by specific tensional force without using a preparatory plan an a tool when fixing the round material to the chuck. SOLUTION: This chuck is provided with a diametrally contractible collet for gripping the round material, collet positioning members for centering and positioning the collet by sandwiching the collet by a chuck body and a tensioner and a magnet structure composed of an N type yoke and an S type yoke in the collet positioning members. The mutual collect positioning members are approached by magnetic force by carrying an electric current to an exciting coil of the magnet structure. A collet diameter contracting member is arranged for diametrally contracting the collet so that the round material is always fixed by the specific tensional force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck for holding an object to be gripped with a uniform pressure by reducing the outer diameter of a body to be gripped, and for processing or measuring a round material or gripping a tool.

[0002]

2. Description of the Related Art At present, hand clamping is generally used for clamping a round material such as a drill or a milling tool in a holder. Representative examples of the hand tightening method include (1) a collet holder and (2) a hydro chuck. The collet holder is designed to reduce the diameter by rotating the nut at the tip of the holder main body and moving the collet in the axial direction to uniformly press and hold the round shaft fitted in the center hole of the collet from the outer periphery using a tool. When the nut is screwed in, the shaft is firmly fixed. In addition, the hydro chuck uses the high pressure of the oil built into the holder body and the elastic deformation of the metal sleeve to strongly grip the inserted round shaft. It is possible to add A tool for elastically deforming the metal sleeve is a wrench, and the work is hand-tightened.

[0003]

In the prior art, the method of clamping a round material is generally manual tightening. In the case of manual tightening, a setup tool for holding the shank and tightening the screw is required. With the high speed rotation of the spindle, there are several standards for the shank shape.
In order to cope with this, it is necessary to devise a method of replacing a fastening setup part. Further, different fasteners are required for each type and size of the holder, so that the setup and management of the tools require labor and time. In the conventional holder, the clamping force at the time of fixing tends to vary because the screw is manually tightened. Further, the strength of the screw portion is required, so that the material of the holder portion is limited, and the types of tools that can be gripped are also limited. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the related art, and has as its object to generate a constant tightening force without the need for a tool or setup to reduce the diameter of a collet. It is an object of the present invention to provide a high-precision chuck having a good balance that can be performed.

[0004]

According to a first aspect of the present invention, there is provided a chuck according to the first aspect of the present invention, wherein a hole for holding a round material is formed at the center and an axial taper is formed at least at one end of the outer periphery. A possible collet, a collet positioning member for positioning the collet by providing a taper hole corresponding to the shaft taper in at least one of the chuck body and the tensioning body for centering the collet, and the chuck body and the tensioning body. A collet reducing member is provided on one of the magnets to reduce the diameter of the collet by attracting the other magnet at the time of excitation.

In the chuck according to the first aspect, as a means for reducing the diameter of the collet, a collet positioning member including a chuck body and a tightening body is provided for centering the collet and reducing the diameter of the collet. This is achieved by using a cooperative magnet's attractive force without using a screw to clamp the collet between the chuck body and the tightening body and approach them. Therefore, the force for reducing the diameter of the collet is always constant, and no special setup or tool is required.

According to a second aspect of the present invention, in the chuck of the present invention, the collet reduced-diameter member is symmetrical with respect to an axis thereof around an outer periphery of a center hole of one of the chuck body and the tightening body. An N-type yoke formed by adsorbing the N pole surface of the first permanent magnet on each side surface of the first yoke provided in parallel with one or more pairs, and the S of the first permanent magnet is formed on each side surface of the first yoke. An S-type yoke formed by adsorbing a pole surface, an S-pole surface of a second permanent magnet at one end of the N-type yoke, and an N-pole surface of a second permanent magnet at one end of the S-type yoke. A magnet structure in which the N-type yoke and the S-type yoke are alternately arranged by adsorbing and aligning the second permanent magnets at the same end to form a square or circular shape, and the second permanent magnet, respectively. An exciting coil in which an energizing coil is wound around the outer periphery of the first coil; The other end of the S-type yoke generates an N-pole at the other end, and the S-type yoke generates a S-pole at the other end of the first yoke, and attracts either the tensioner or the chuck body to shrink the collet. And the direction of energization to the exciting coil is reversed so that the N-pole and S-pole generated at the other end are eliminated to eliminate the suction of the second yoke and recover the diameter of the collet. It was made.

The chuck according to a second aspect of the present invention is provided with a magnet structure that generates a strong attractive force as a collet diameter reducing member. An N-pole and an S-pole are alternately generated on the end face of the first yoke by the first short-time energization of the exciting coil of the magnet structure to form a permanent magnetic circuit with the second yoke. To maintain adsorption. In this state, the N-pole and the S-pole on the end face of the first yoke disappear by the next short-time reverse energization. As a result, the magnetic circuit with the second yoke also disappears and is released from the adsorption. Therefore, since it is not necessary to constantly supply power to maintain the diameter of the collet reduced, a device for this purpose is not required.

According to a third aspect of the present invention, there is provided the chuck, wherein the cross section of the first yoke is formed in a square shape. The chuck according to claim 3 is characterized in that the first yoke is made up of a condition necessary for securing a magnet attraction force sufficient to support the tool by the shape and weight of the tool and a condition required for an outer shape allowed for the chuck. It means that the shape is designed.

According to a fourth aspect of the present invention, there is provided the chuck, wherein the cross section of the first yoke is formed in a fan shape. In the chuck of the fourth aspect, when the shape of the first yoke is designed to be a fan shape, the outer shape can be designed to be compact with a circular shape.

Further, in the chuck according to the present invention, a magnetic force acts between the chuck body after the mounting and the tensioning member before energizing the exciting magnet coil to reduce the diameter of the collet. A third permanent magnet is provided on at least one of the tightening body and the chuck body so as to perform the operation. In the chuck according to the fifth aspect, the collet is fitted into the tapered hole of the chuck body after the chuck body is mounted in the tapered hole of the main shaft, and the collet is pushed in the axial direction by the tightening body, and the collet is completely inserted into the tapered hole of the chuck body. Both of the tightening bodies are attracted by the third permanent magnet in a state where they are in close contact with each other. When the chuck is mounted on the vertical spindle, the tightening bodies are prevented from dropping. Energize the exciting coil to make the first yoke and the second yoke
Until the yoke is adsorbed, it is attracted by the third permanent magnet.

Further, in the chuck according to the present invention, the chuck body and the tensioning member may be connected to each other before the magnetic force by the third permanent magnet is applied between the clamping member and the chuck body. A threaded or bayonet-coupled engaging portion for engaging the body, and moving out of the engaging portion in the axial direction of the chuck body to suck the chuck body and the tensioning body. It is. In the chuck according to the sixth aspect, the engagement between the chuck body and the tensioning member before energization is further ensured.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a chuck 1 according to a first embodiment of the present invention. A magnet structure 4 is provided on the chuck body 2. FIG. 3 is an enlarged sectional view of the magnet structure 4 provided on the chuck body 2 shown in FIG. The power supply unit of the magnet structure 4, the temporary holding unit 5 of the tightening body 3 by the third permanent magnet 5, and the engaging unit 6 of the chuck body 2 and the tightening body 3 by screwing or bayonet are shown. FIG. 3 shows an embodiment in which the guide holes for the collet 7 are provided on both the chuck body 2 and the tensioning member 3, whereas the guide holes for the collet 7 are provided only on the chuck body 2 side. FIGS. 5A, 5B, and 5C are layout diagrams of an N-type yoke and an S-type yoke constituting the magnet structure 4. FIG. FIGS. 6A and 6B are explanatory diagrams of functions of the N-type yoke and the S-type yoke constituting the magnet structure 4.

[0013]

[Embodiment 1] In FIG.
(Shown in FIG. 5) is provided on the chuck body 2. The collet 7 is a spring collet that reduces its diameter, and includes a tapered hole 2a of the chuck body 2 and a tension member 3 facing the hole.
Of the tapered hole 3a. A round hole is formed in the collet 7 so that a round material 8 can be inserted into the center. As the round material 8, a drill, a milling tool, a work to be measured, or the like can be considered. The tightening body 3 formed in a bowl shape and having a tapered hole 3a engraved at the center of the bottom has an engaging portion 6 which is engaged with the upper inner diameter portion and the lower outer diameter portion of the chuck body 2 by a screw or bayonet. Is provided.

A collet 7 is sandwiched between the chuck body 2 having the tapered hole surface 2b and the tightening member 3, and the tightening member 3 escapes from the engagement portion 6 with the holder body 2, and the collet 7 forms the tapered hole 2a and the tapered hole. 3a. This positioning state depends on the material of the chuck body 2 and the tension body 3.
A third permanent magnet 9 is provided on the end faces facing each other and is attracted and held in the gap S1. The attraction force of the temporarily held third permanent magnet 9 does not have to have an axial force enough to reduce the diameter of the collet 7. In the state of being sucked, a gap of S2 is left between the tension member 3 and the first yoke 10.

When the material of the tension member 3 shown in FIG. 3 is an aluminum-based light metal or other non-ferrous metal or non-magnetic metal, a second yoke 20 must be separately added to the surface facing the first yoke. There is. The basic structure of the magnet structure 4 for controlling the diameter reduction of the collets 7, 22 constituting the chucks 1, 11, 21 is common. However, the shape and size of the collet 7 depend on the diameter of the round material 8, and the collet 7 depends on the weight of the round material 8.
The outer dimensions of the magnet structure 4 for reducing the diameter are determined by design. It is desirable that the chuck be configured to have as small an external dimension as possible in handling. Therefore, it is required to design the magnet structure 4 that exhibits the maximum attractive force within the allowable dimensions.

FIG. 5 is a layout view of the N-type yoke 12 and the S-type yoke 13 constituting the magnet structure 4 and can be applied commonly to the first to third embodiments. FIG. 5A is a diagram in which a first yoke 10 having a quadrangular cross section chamfered on an outer peripheral portion of the mounting surface 2a of the collet 7 is arranged in a square shape. The configuration of the first yoke 10 and the first permanent magnet 14 will be described later. FIG.
2B, the cross section of the first yoke 10 is formed in a sector shape, the outer periphery is polygonal, and the first permanent magnets 14 are arranged, so that the magnet structure 4 can be made compact.

FIG. 5C is a layout view of the first yoke 10 when the shape of the collet 7 is large. The first yoke 10 is subdivided, but the N-type yoke 12 and the S-type yoke 12 are provided. 13 can increase the attraction force of the magnet structure 4 composed of the magnet 13 and the collet 7 can be designed to have a large ability to reduce the diameter.

Next, the configuration of the first yoke 10 and the first permanent magnet 14 in the N-type yoke 12 and the S-type yoke 13 will be described. This configuration can be applied commonly to the first to third embodiments. FIG. 6 shows a sectional view of the magnet structure 4. In FIG. 6A, an N-type yoke 12 and an S-type yoke 13 are arranged adjacent to the chuck body 2 (or the tension member 3). The N-type yoke refers to an even number of first yoke 10 having the N pole face of one or more first permanent magnets 14 attracted to the adjacent side face, and the S-type yoke attracts the S pole face. Means the one formed.

The S pole face of the second permanent magnet 15 is attracted to one end 10c of the N-type yoke 12 to which the first permanent magnet 14 is not attracted. The magnetic pole surface of the N pole of the magnet 15 is attracted. An exciting coil 16 is wound around the outer periphery of the second permanent magnet 15 along an axis perpendicular to the attraction surface between the second permanent magnet 15 and the first yoke 10. A second yoke 17 is provided at the other end 10d of the first yoke 10 with a gap S2 therebetween. The gap of S2 becomes 0 because
When the excitation coil 16 is energized, the end face 10a of the first yoke 10
In the case of the N-type yoke 12, an N pole is generated, and in the case of the S-type yoke 13, an S pole is generated. A magnetic circuit is formed with the second yoke 20, and the second yoke 20 is attracted. [Figure 6]
(A)]. Here, the second yoke 20 is added as a separate component when the chuck body 2 or the tensioning body 3 does not form a magnetic circuit.

Next, the operation of the magnet structure 4 of the present invention will be described with reference to FIGS. The collet 7 is fitted into the center tapered hole 2 a of the chuck body 2, and is engaged with the engaging portion 6 between the tightening body 3 and the chuck body 2 while engaging the taper hole 3 a of the tightening body 3. The tension member 3 is attracted to the chuck body 4 by the third permanent magnet 9. At this stage, since the first yoke 10 is not energized to the exciting coil 16, no polarity appears at the end 10 a of the first yoke, so that no attractive force acts. 3 and 6, the second yoke 20 is shown. 6 (a) and 6 (b), the illustration of the collet 7 is omitted. In FIG. 1, the tension body 3 functions as a second yoke, and in FIG. 2, the chuck body 2 functions as a second yoke.

In FIG. 6A, before the excitation coil 16 is energized, the N-type yoke 12 is connected to the first permanent magnet 14 and the second permanent magnet 14.
A magnetic circuit is formed between the permanent magnet 15 and the first yoke 10, and the end face 10d of the first yoke 10 has no polarity. FIG. 6B shows a state in which the excitation coil 16 is energized for a certain period of time to cut off the current.

In FIG. 3, when the chuck 1 is moved and supplied with power so that the power supply ring 19 is brought into contact with a power supply contact (not shown), the excitation coil 16 is excited via the conducting wire 17. In FIG. 6B, the end of the exciting coil 16 is
Since the first yoke 10 is excited so as to show the polarity opposite to the polarity of the second permanent magnet 15, the first yoke 10 shows the N pole and the S pole alternately, and the N-type yoke 12 and the S-type yoke 13 are formed. Is done. As a result, the first yoke 10 and the second yoke 20 form a closed magnetic circuit, and the attraction function is strongly exerted.

As described above, the chuck body 2 and the tension member 3 are sucked, the gap S2 becomes zero, and the collet 7 is reduced in diameter and grips the round material 8. Thus, the magnetic circuit is continuously maintained even when the energization is stopped. Next, when power is supplied again, FIG.
The state shown in FIG. 6B changes to the state shown in FIG. 6A, the polarity of the end 10b of the first yoke 10 disappears, and the first yoke 10 and the second yoke 20 are separated.

Embodiment 2 FIG. 2 is a sectional view of a chuck 11 according to Embodiment 2 of the present invention. A magnet structure 4 is provided on the clamp. In the chuck 11 shown in FIG. 2, the magnet structure 4 is provided on the tension member 3. Except for the design change based on this point, the configuration is common to the chuck 1 shown in FIG.

FIG. 3 is an enlarged sectional view of the structure of the chuck 1 including the magnet structure 4. In FIG. 3, the magnet structure 4
The N-type yoke 12 and the S-type yoke 13 are arranged at symmetrical positions with respect to the center of the chuck as illustrated in FIG. The excitation coil 16 is energized to generate a magnetic pole at the portion 10a of the first yoke. For power supply, a power supply 19 supported by an insulator 18 is provided on a flange 2 c of the chuck body 2. The conducting wire 17 connected to the power supply 19 is connected to the exciting coil 16 through a hole 2 c formed in the chuck body 2. The N-type yoke 12 has an N-pole at the end 10a of the first yoke 10 and an S-pole at the S-type yoke upon energization.

When the material of the tension member 3 is a non-magnetic material, a ring-shaped second yoke 17 is specially added to the bottom surface 3b of the tension member 3 so that a magnetic pole generated in the first yoke and a magnetic circuit are formed. Is formed to suck the tension member 3 and compress the gap S2. When the gap of S2 is compressed, the collet 7 is reduced in diameter, and the pressed round material 8 is evenly pressed from the outer diameter to be gripped. The arrangement diagram of the N-type yoke and the S-type yoke shown in FIG. 5 is applicable to the second embodiment. Since the description has been made in the first embodiment, the description is omitted here. The function of the magnet structure shown in FIG.

Third Embodiment FIG. 4 is a sectional view of a main part of a chuck 21 according to a third embodiment of the present invention. The chuck 21 shown in FIG. 4 is similar to the chuck 1 in FIG. 3 in that the magnet structure 4 is provided on the chuck body 2. The collet 22 is positioned at an axial tapered surface corresponding to the tapered hole 2a,
a is the holding surface 24a of the holding plate 24 integrated with the tension member 23
And is temporarily held in the axial direction by the attractive force of the third permanent magnet 9. The radial direction of the tension member 23 is the chuck body 2
The inner diameter surface 23a of the tensioning member 23 is guided by the outer diameter surface 2e. The relationship between the engaging portion 6 between the tension member 23 and the chuck body 2, the relationship between the tension member 23 and the third permanent magnet, the relationship between the tension member 23 being strongly attracted by the magnet structure 4, and the second relationship.
The relationship of adding the yoke is as described with reference to FIG. The arrangement of the N-type yoke and the S-type yoke described in the first embodiment with reference to FIG. 5 is common. The function of the magnet structure shown in FIG.

[0028]

Since the apparatus according to the present invention is constructed as described above, the following effects can be obtained. When the round material is fixed to the chuck, first, a setup for holding the shank portion of the chuck and tightening the screws is necessary, and diversification of the shank requires preparation preparation and man-hours for management. In addition, types of tightening tools are increased, and management tends to be performed frequently.

By using the chuck of the present invention, no setup is required when the round material is attached to the chuck, and no tightening tool is required. In addition, a constant tool gripping force is obtained, and the rotation balance of the chuck is extremely good. Furthermore, it is excellent in repetitive tightening accuracy and is effective in reducing labor and time loss in the tightening operation. The fact that current is not always supplied to the excitation coil of the magnet structure is also economically advantageous.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a chuck described in Embodiment 1 of the present invention. FIG. 6 is a view of an embodiment in which a guide surface of a collet is provided on both the chuck body and the tightening body, and a magnet structure is provided on the chuck body side.

FIG. 2 is a cross-sectional view of a chuck described in Embodiment 2 of the present invention. FIG. 4 is a view of an embodiment in which a guide surface of a collet is provided on both the chuck body and the tightening body, and a magnet structure is provided on the tightening body side.

FIG. 3 is an enlarged view of the magnet structure of FIG. 1 of the chuck of the present invention. It is a figure including a power supply part to an excitation coil, a temporary holding part by the third permanent magnet, and a screwed part of the chuck body and the tightening body.

FIG. 4 is an enlarged view of a magnet structure of a chuck described in Embodiment 3 of the present invention. FIG. 4 is a diagram in which a magnet structure is provided on the chuck body side, the tensioning body is a non-magnetized metal, and a guide surface of a collet is provided only on the chuck body side.

FIG. 5 is an arrangement diagram of an N-type yoke and an S-type yoke in the magnet structure of the present invention. This is applied to the chucks described in the first to third embodiments. (A) is an example of a square arrangement, applicable to small diameter collets,
(B) is an example of a circular arrangement, applicable to medium-diameter collets, (c)
Is a square arrangement, applicable to large diameter collets.

FIGS. 6A and 6B are explanatory diagrams of a magnet structure constituting the present invention in the case of energization demagnetization, and FIG. This is applied to the chucks described in the first to third embodiments. (A) is a case in which the excitation coil is temporarily energized so as to have the same polarity as the magnetism of the second permanent magnet. There is no magnetic circuit between the first yoke and the second yoke. (B) is a diagram when the excitation coil is temporarily energized so as to generate a polarity opposite to the magnetic pole of the second permanent magnet. In FIG. 6, the collet is omitted.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 11, 21 Chuck 2 Chuck main body 3 Tension body 4 Magnet structure 5 Temporary holding part 6 Engaging part 7,22 Collet 8 Round material 9 Third permanent magnet 10 First yoke 12 N-type yoke 13 S-type yoke Iron 14 First permanent magnet 15 Second permanent magnet 16 Excitation coil 17 Conductor 18 Insulator 19 Feeder 20 Second yoke 23 Holding plate

Claims (6)

[Claims] 1. A collapsible collet having a hole for holding a round material at the center thereof and an axial taper formed at least at one end of an outer periphery thereof, and the axial taper provided on at least one of a chuck body and a tightening body for centering the collet. A collet positioning member for positioning the collet by providing a tapered hole corresponding to
A chuck comprising a collet reducing member for reducing the diameter of the collet by providing an exciting magnet on one of the chuck body and the tensioning body to attract the other during excitation and reducing the diameter of the collet. 2. A side face of a first yoke in which one or more pairs of said collet reducing members are provided symmetrically and parallel to the axis thereof around the center hole of one of said chuck body and said tightening body. An N-type yoke formed by adsorbing the N-pole surface of the first permanent magnet; and an S-type yoke formed by adsorbing the S-pole surface of the first permanent magnet on each side surface of the first yoke. The S pole face of the second permanent magnet is attracted to one end of the N-type yoke and the N pole face of the second permanent magnet is attracted to one end of the S-type yoke to align the second permanent magnet with the same end. A magnet structure in which the N-type yoke and the S-type yoke are alternately arranged to form a square or circular shape, and an exciting coil in which a current-carrying coil is wound around each outer periphery of the second permanent magnet. An N pole is generated at the other end of the first yoke of the N-type yoke by energizing the exciting coil, and the first type of the S-type yoke is generated. A magnetic pole of S pole is generated at the other end of the yoke, and the collet is contracted by sucking either the tightening body or the holder body, and the direction of current supply to the exciting coil is reversed to the other end. The chuck according to claim 1, wherein the generated magnetic poles of the N pole and the S pole are eliminated to eliminate the suction of the second yoke and recover the diameter of the collet. 3. The chuck according to claim 2, wherein a cross section of the first yoke is formed in a square shape. 4. The chuck according to claim 2, wherein the cross section of the first yoke is formed in a fan shape. 5. Before the energizing magnet coil is energized to reduce the diameter of the collet, at least one of the tensioning body or the chuck body is configured to apply a magnetic force between the attached chuck body and the tensioning body. 3. The chuck according to claim 1, wherein a third permanent magnet is provided on one side. 6. A screw or bayonet connection for engaging the chuck body and the tension member before applying a magnetic force by the third permanent magnet between the tension member and the chuck body. The chuck according to claim 3, further comprising a joining portion, wherein the chuck body moves in the axial direction of the chuck main body after the engagement portion escapes to suck the chuck main body and the tension member.