KR20150117419A - Apparatus for Electrically Driving a Shaft and Method for Working the Same - Google Patents

Abstract

The present invention relates to an apparatus and a method for controlling a gripping force of a machining apparatus, such as a cutting apparatus, a cutting apparatus, and the like, which can independently control rotational motion and linear motion of a shaft, The present invention relates to a shaft driving device and a method of operating the same, in which a linear moving linearly rotates relative to the outer side of a coaxial shaft by a plurality of bearing structures, is disposed inside the housing and linearly coaxial linear movement and rotation It is possible to operate by an independent system by separating the motion, and in the linear transfer, the clamping portion requiring a simple transferring portion and a large chucking force is independently operated and operated, thereby achieving a high thrust density per unit volume And an operation method thereof.

Description

Technical Field [0001] The present invention relates to an electric shaft driving apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a driving device for rotating and linearly moving a shaft, and more particularly to a driving device for rotating and linearly moving a shaft, To thereby precisely control the gripping force of the machining mechanism, and an operation method thereof.

Generally, machining machines such as a molding apparatus, a cutting apparatus, and a grinding apparatus have axes for rotating and linearly moving a tool or a workpiece. As a shaft driving device for rotating and linearly moving such a shaft, a shaft driving assembly of a rotary hydraulic cylinder structure such as that disclosed in Korean Patent Registration No. 10-0732596 (registered on Jun. 20, 2007) has been mainly used.

In the rotary hydraulic cylinder of the above-mentioned patent, a hydraulic cylinder having a piston linearly moving by hydraulic pressure is installed through a hollow shaft motor, the rotor of the motor is mounted on the outer surface of the hydraulic cylinder, So that the hydraulic cylinder can be rotated.

Such a rotary hydraulic cylinder is configured to prevent oil in the cylinder housing from leaking into the cylinder housing and the cylinder body gap by a mechanical seal. However, due to the centrifugal force, there is a problem in that oil seeps into the gap between the mechanical seal and the cylinder body .

In addition, in the ultra-high speed rotary hydraulic cylinder, the impeller blade for cooling the heat generated inside and outside the cylinder by the high-speed rotation of the cylinder is installed so as to protrude to the outside, but only the surface of the cylinder is cooled, There is a problem that can not be done.

In order to solve this problem, Korean Utility Model Publication No. 20-0243368 (registered on Aug. 7, 2001), an impeller is installed between the cylinder housing and the cylinder cover to efficiently cool the heat generated inside, The wing is formed to communicate with the inside of the cylinder housing to increase the suction amount of the air and to position the suction position of the air as the super head of the cylinder to cool the cylinder housing and the cylinder cover outer heat and to form an air flow seat inside the product There is disclosed a rotary hydraulic cylinder for a CNC lathe in which heat generated inside is cooled in a short time to prevent components in the cylinder from being dislodged. However, the rotary hydraulic cylinder of the registration utility model publication can not reduce or eliminate the heat generated by the rotation of the cylinder, and the impeller blade must be additionally constructed, which complicates the structure.

Since the conventional shaft driving device for moving the shaft in the machining machine is required to install a separate sealing device or a cooling device by rotation of the shaft, the structure of the system is complicated and inefficient. In the system for rotating the shaft, There is a problem that the efficiency of the entire system of the shaft driving device for linearly moving and rotating the shaft is lowered.

In addition, the conventional hydraulic clamping apparatus disclosed in Korean Patent Laid-Open Publication No. 2001-0102862 has a problem in that a hydraulic tank for using hydraulic oil is used and thus a large space occupies a lot of space and a large number of hoses are used between the clamping devices in the hydraulic tank There is a problem that the circumference of the apparatus is complicated and the working environment is contaminated by the leakage of the hydraulic oil, and there is a difficulty in maintenance that the hydraulic oil must be periodically replaced. Such a clamping device by hydraulic pressure has a slow response speed and it is difficult to precisely control the gripping force of the chuck, which may cause deformation of the workpiece depending on the characteristics of the material.

Also, in the case of a clamping device for gripping a workpiece, a screw jack is used in a linear motion. The screw jack has a low mechanical efficiency due to a high frictional force, and has a problem of uncertainty of control due to backlash and low running speed.

As a device capable of obtaining a large force by an electric input driving source, there is an actuator or a linear motor using a solenoid type. Since the force generated by the solenoid type decreases in proportion to the square of the distance, the movement distance of the plunger is made larger than a certain degree And is used only for a very short range of motion. On the other hand, when a linear motor is used, a large current of several hundred amperes or more is required to obtain a large thrust of about 20 kN. Therefore, both the heat generation and the cooling problem in the coil must be taken into consideration.

Registered Patent Publication No. 10-0732596 (registered on June 20, 2007): a driving assembly for rotating and moving a shaft Registration Utility Model Bulletin No. 20-0243368 (registered on August 7, 2001): Rotary hydraulic cylinder for CNC lathe

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and it is an object of the present invention to provide a rotary member in which a linear moving linearly rotates relative to the outer side of a coaxial shaft by a plurality of bearing structures, It is possible to separate the rotary motion of the rotary member and operate it by an independent system and to separate the clamping part requiring a simple transferring part and a large chucking force independently in the linear transferring operation, An electric shaft driving device capable of realizing a high thrust density and an operation method thereof.

According to an aspect of the present invention, there is provided an electric shaft driving apparatus including: a housing; A linear coaxial shaft extending along the longitudinal direction of the housing and linearly moving in the axial direction while being rotated; A clamping block installed inside the housing and generating a magnetic field by an external power source; A clamping plate provided on one side or both sides of the clamping block so as to be movable only in the longitudinal direction with respect to the housing and moving toward and attached to the clamping block by a magnetic field generated in the clamping block; A guide boss fixedly installed at a central portion of the clamping plate, the guide boss being formed on an inner circumferential surface of the linear shaft to be screwed with a coaxial screw thread; A driving block having the linear shape connected to the coaxial through hole and linearly rotating together with the coaxial line; A linear driving unit for linearly rotating the driving block to generate coaxial rotational motion and axial linear motion; A rotating member installed on the inside of the housing so as to be linearly spaced apart from the outer circumferential surface of the coaxial shaft and configured to rotate with respect to the housing; An inner bearing unit in which the linear member is coupled to an outer surface of the coaxial shaft, the linear member being coaxial with the rotary member, and linearly moving with respect to the rotary member along with the coaxial shaft; An outer bearing unit provided between the inner circumferential surface of the housing and the outer circumferential surface of the rotary member and rotatably supporting the rotary member with respect to the housing; And rotation driving means coupled to a front end portion of the rotation member to rotate the rotation member about the housing and the linear axis with respect to the coaxial axis.

The present invention provides a shaft driving apparatus that includes a linear driving unit for linearly moving a linear coaxial line to a set position and a clamping block for generating a magnetic force by electricity by a separate clamping operation for transmitting a second strong gripping force, Since the dual shaft drive system in which the plate is implemented is implemented, it is possible to provide a large clamping force comparable to the hydraulic pressure without using the hydraulic pressure, and it is possible to provide a high thrust density per unit volume.

Accordingly, it is possible to easily control the holding force of the chuck, minimize the deformation of the workpiece, and achieve an effective automation of the chucking system.

Since the inner bearing unit and the outer bearing unit provided inside the housing can stably support the thrust due to linear movement of the coaxial shaft and the radial load due to the high rotation of the rotary member, the operation stability is improved and the installation is easy There is an advantage to be lost.

In addition, it is easy to secure space in the machine tool or the workplace, and the workplace can be kept clean. In addition, it is possible to reduce the weight of the system, to reduce the cost, and to realize an environment-friendly and high-efficiency shaft driving device than the conventional hydraulic method.

1 is a cross-sectional view of an electric shaft drive according to an embodiment of the present invention.
Fig. 2 is a cross-sectional view and a front view of a linear coaxial shaft of the electric shaft drive device of Fig. 1;
3 is a perspective view of a clamping block of the electric shaft drive device of FIG.
4A and 4B are longitudinal sectional views of the clamping block of Fig.
Fig. 5 is a cross-sectional view of the clamping plate in the engaged state of the electric shaft driving device of Fig. 1;
Fig. 6 is a cross-sectional view showing the respective parts of the clamping plate of Fig. 5 together with a front view and a perspective view.
FIG. 7 is a cross-sectional view and a front view and a perspective view of the clamping plate and the clamping block of FIG. 5 in combination;
FIG. 8 is a cross-sectional view showing a state in which the linear axis of the electric shaft driving apparatus of FIG. 1 is advanced. FIG.
Fig. 9 is a cross-sectional view showing a state in which the linear axis of the electric shaft driving apparatus of Fig. 1 is reversed from the state shown in Fig. 8;
Fig. 10 is a cross-sectional view showing a state in which the linear axis of the electric shaft driving device of Fig. 1 is reversed by the action of the clamping block and the clamping plate. Fig.
11 is a cross-sectional view of an electric shaft drive apparatus according to another embodiment of the present invention.
12 is a perspective view of the impeller of the electric shaft drive device of FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of an electric shaft driving apparatus and an operation method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

In order to facilitate understanding in the following description of the embodiment, the right side of the drawing will be described as the front side of the apparatus, and the left side as viewed from the drawing will be described as the rear side of the apparatus.

Referring to FIG. 1, an electric shaft driving apparatus of the present invention includes a housing 10; A linear coaxial shaft 20 installed on the housing 10 so as to extend along the longitudinal direction of the housing 10 and linearly move in the axial direction while rotating and having threads 21 formed on the outer circumferential surface thereof; A clamping block 40 installed in the housing 10 for generating a magnetic field by an external power source; The clamping block 40 is installed on one side or both sides of the clamping block 40 so as to be movable only in the longitudinal direction with respect to the housing 10 and is moved toward and attached to the clamping block 40 by a magnetic field generated in the clamping block 40 A clamping plate 50 made of a magnetic material; A guide boss 55 fixedly installed at a central portion of the clamping plate 50 and having an inner thread surface formed with a female thread 56 which is linearly engaged with the thread 21 of the coaxial shaft 20; A drive block 65 having the linear shape connected to the coaxial shaft 20 by a spline structure and linearly rotating together with the coaxial shaft 20; A linear drive unit for linearly rotating the driving block (65) to generate rotational motion and axial linear movement of the coaxial shaft (20); A rotary member 30 installed on the inside of the housing 10 so as to be linearly spaced apart from the outer circumferential surface of the coaxial shaft 20 and configured to rotate with respect to the housing 10; The linear type linear motor is coupled between the coaxial shaft 20 and the rotary member 30 and is linearly coupled to the outer surface of the coaxial shaft 20 to linearly move with respect to the rotary member 30 together with the coaxial shaft 20, A unit 70; An outer bearing unit 80 provided between the inner peripheral surface of the housing 10 and the outer peripheral surface of the rotary member 30 and rotatably supporting the rotary member 30 with respect to the housing 10; And rotation driving means coupled to the front end of the rotary member 30 for rotating the rotary member 30 relative to the housing 10 and the linear axis with respect to the coaxial shaft 20.

The housing 10 has a substantially cylindrical tubular shape, and a circular through-hole through which the linear coaxial shaft 20 passes is formed at the center of the rear surface. The housing 10 is fixed to the body of the processing equipment to which the shaft driving device of the present invention is applied.

As shown in Figs. 1 and 2, the linear coaxial shaft 20 has a circular rod shape having a predetermined length, and a thread 21 is integrally formed at an intermediate portion thereof. On the outer surface of the rear end portion of the linear coaxial shaft 20, a spline groove 22 is formed concavely along the axial direction. A spline protrusion 66 for guiding the movement of the spline groove 22 is inserted into the inner circumferential surface of the hole at the center of the driving block 65 to which the linear type coaxial shaft 20 is connected, Direction. Accordingly, the linear coaxial shaft 20 linearly moves in the forward and backward direction (axial direction) with respect to the driving block 65 by the engagement of the spline groove 22 and the spline projection 66, Relative rotation is impossible and the driving block 65 is rotated.

The driving block 65 is formed in a disc shape having a hole through which the linear coaxial shaft 20 passes and having the spline protrusion 66 formed at the center thereof. The driving block 65 rotates around the outside of the rear end of the housing 10 And is coupled with the linear driving unit and is rotated by the linear driving unit.

The linear drive unit includes an electric motor 61 and a drive gear 62 that is axially coupled to the electric motor 61 and rotates. The linear drive unit 62 is rotated by receiving power from the drive gear 62, And a driven gear 63 to which the driving block 65 is fixedly coupled to the center portion. Accordingly, when the electric motor 61 is energized and the electric motor 61 is operated, the driving gear 62 rotates and power is transmitted to the driven gear 63 to rotate the driven gear 63 And the driving block 65 coupled with the driven gear 63 is rotated together with the driven gear 63. [

The driven gear 63 has a greater diameter than the drive gear 62 and has more teeth than the drive gear 62. [ Accordingly, the power of the electric motor 61 is linearly decelerated to the coaxial shaft 20 by the gear ratio of the driving gear 62 and the driven gear 63, and is transmitted as a large torque. The driving gear 62 and the driven gear 63 may be constructed by applying a spur gear, but may be constructed by applying any gear such as a helical gear or a worm gear.

In this embodiment, a gear is used to transmit the power of the electric motor 61 to the drive block 65. Alternatively, a belt having a gear ratio or a known power transmission mechanism may be used to transmit the power of the motor to the drive block 65 Of course.

The clamping block 40 is installed to be electrically connected to an external control device (not shown) in a rear portion of the housing 10 and receives power from the control device. The clamping block 40 is selectively provided on both sides, So that a magnetic field can be generated. In this embodiment, the two clamping blocks 40 are arranged at a predetermined interval in the longitudinal direction of the housing 10. Alternatively, however, only one clamping block 40 or three or more clamping blocks 40 may be arranged.

3 to 4B, the clamping block 40 includes a disc-shaped stator core 41 fixed to the inside of the housing 10, and a power source wound around the stator core 41 and externally applied thereto And a coil 42 for generating a magnetic field. A plurality of flange portions 44 each having a bolt insertion hole 44a are arranged at regular intervals in the circumferential direction on the outer peripheral portion of the stator core 41.

 A plurality of slots 43 are formed on both sides of the clamping block 40 so that the coil 42 is wound around the clamping block 40. Power is selectively applied to the coil 42 wound on both sides of the clamping block 40, A magnetic field is selectively generated on both sides of the block 40. The magnetic field generated on either side of the clamping block 40 does not affect the other side of the opposite side.

The clamping block 40 is preferably impregnated with a synthetic resin such as an epoxy resin to dissipate the heat generated from the coil 42.

The directions of the currents flowing through the coils 42 wound on the two side slots 43 of the clamping block 40 may be the same as those shown in FIG. 4A, or alternatively, as shown in FIG. 4B, .

5 to 7 show the configuration of the clamping plate 50 which linearly moves in the longitudinal direction of the housing 10 (the linear direction is the same as the axial direction of the coaxial axis) by the magnetic field generated by the clamping block 40 . The clamping plates 50 are arranged at predetermined intervals along the longitudinal direction of the housing 10 (three in this embodiment, denoted by 50a, 50b and 50c in order from the front in order to facilitate understanding) And a predetermined gap with the surfaces of the two clamping blocks 40. The clamping plate 50 is installed inside the housing 10 so that it can move only in the longitudinal direction of the housing 10 without rotating.

In the center of the clamping plate 50, a guide boss 55 in the form of a circular tube through which the linear coaxial shaft 20 passes is integrally formed. In this embodiment, the clamping plate 50c and the center A guide boss 55 is formed on the clamping plate 50b positioned on the inner circumferential surface of the guide boss 55. On the inner circumferential surface of at least one of the guide bosses 55 And a female thread 56 which is helically engaged with the female thread 21 is formed.

A plurality of bolt fastening holes 52 for fastening bolts 57 (see FIG. 1) for interconnecting the plurality of clamping plates 50a, 50b, 50c are formed on the outer periphery of the clamping plates 50a, 50b, Respectively.

A plurality of rotation preventing grooves 51 for preventing the rotation of the clamping plate 50 are formed at predetermined intervals on the outer circumferential edge of the clamping plate 50. The flange portions 44 of the clamping block 40 Is provided with an arc-shaped anti-rotation member (45) inserted into the rotation preventing groove (51). The outer circumferential portions of the rotation preventing member 45 and the clamping block 40 are fixed to the housing 10 while being coupled to each other by a plurality of bolts 47 whose ends are spirally coupled to the housing 10. The anti-rotation member 45 and the clamping block 40 may be formed as an individual body, but may otherwise be integrally formed.

1, the inner bearing unit 70 is coupled to the front portion of the coaxial shaft 20 linearly inside the front portion of the housing 10, , While supporting the thrust by the linear movement and maintaining the coaxiality. In this embodiment, the inner bearing unit 70 includes a plurality of (four) inner bearings 71 whose inner ring is coupled to the coaxial shaft 20, and a plurality of (four) inner bearings 71 coupled to the outer ring of the inner bearings 71, And an inner bearing housing 72 which is axially slidably connected to the inner circumferential surface of the housing 30. A draw-bar joint 75 of a draw bar D connected to the chuck is coupled to the front end of the inner bearing housing 72.

A key groove 32 is formed on the inner circumferential surface of the rotary member 30 so as to extend in the axial direction and a key 73 is provided on the inner bearing housing 72 so as to be slidable along the key groove 32, Respectively. Therefore, when the linear shape of the coaxial shaft 20 linearly moves, the key 73 of the inner bearing housing 72 slides along the keyway 32 of the rotary member 30, .

The outer bearing unit 80 includes a plurality of bearings (four bearings in this embodiment, but may be formed in various other numbers) provided between the outer circumferential surface of the rotary member 30 and the inner circumferential surface of the housing 10 So as to support the radial load of the rotary member 30 with respect to the housing 10 when the rotary member 30 rotates.

The rotary member 30 has a cylindrical shape with open front and rear faces, and the front end is engaged with the connecting disc 90 constituting the rotation driving means. The connecting disc 90 is formed in a disc shape having a through hole 91 formed at its center and is coupled to the front end of the rotary member 30 by a plurality of bolts 92. Although not shown in the drawing, the rotation driving means includes an electric motor, a spindle connected to the coupling disk 90, and a power transmitting member (for example, a belt) for connecting the power of the electric motor to the spindle . A tip end portion of a spindle constituting the rotation driving means is connected to a mechanism such as a chuck for gripping a tool or a workpiece in the machining equipment.

In this embodiment, a chuck for holding a workpiece is coupled to one end of a spindle (not shown), and an inner bearing unit 70 coupled to the front end of the coaxial shaft 20 is connected to a drawbar joint ) 75 via the drawbar D connected to the chuck.

Hereinafter, an operation method of the electric shaft driving apparatus of the present invention will be described in detail.

First, when power is applied to the electric motor 61 of the linear drive unit at the initial position as shown in FIG. 1, the rotational force of the electric motor 61 is transmitted to the driven gear 63 via the drive gear 62, The gear 63 is rotated. At this time, the power of the electric motor 61 is decelerated by the gear ratio of the drive gear 62 and the driven gear 63, and is transmitted to the drive block 65 with a large torque as described above.

Since the linear coaxial shaft 20 and the driving block 65 are connected in a spline structure, the linear coaxial shaft 20 rotates together as the driving block 65 rotates. Since the linear diaphragm 20 is threadably engaged with the female threads 56 of the guide bosses 55, the linear diaphragm 20 is supported by the threads 21 and the female threads 56 And moves linearly in the axial direction (toward the right side in the drawing) while advancing. At this time, the inner bearing housing 72 of the inner bearing unit 70, which is linearly coupled to the front of the coaxial shaft 20, slides along the inner circumferential surface of the rotary member 30 and supports the load due to the linear movement.

(See FIG. 8), the linear motion of the coarse shaft 20 and the inner bearing unit 70 is advanced to a predetermined position and then linearly moved (see FIG. 8) And the workpiece is put between the chucks (not shown).

When the electric motor 61 is rotated in the direction opposite to the previous direction, the driving block 65 and the linear connected thereto are rotated in the direction opposite to the previous direction, and the guide boss The linear movement of the coaxial shaft 20 linearly moves in the direction opposite to the previous direction, that is, to the left in the drawing, by the action of the female threads 56 of the coaxial elements 55 and the threads 21 of the coaxial shaft 20 Reference). As a result, the chuck (not shown) is pinched and grips the workpiece (not shown).

In order to process the workpiece, a chuck (not shown) needs to clamp the workpiece more firmly. To this end, when a current is applied to the coil 42 wound on the front side (the right side in the drawing of FIG. 1) of the clamping block 40 and a magnetic field is generated on the front side of the clamping block 40, Similarly, the clamping plate 50 is attracted toward the front side of the clamping block 40 by magnetic force. Since the guide boss 55 and the coaxial shaft 20 of the clamping plate 50 are coupled to each other by the thread 21 and the female thread 56, 20 are linearly moved rearward by a certain distance, and the chuck (not shown) is further pushed inwardly, thereby clamping the workpiece with a large force comparable to the hydraulic pressure.

After the linear movement of the coaxial shaft 20 and the inner bearing unit 70 linearly moves forward and backward and the chuck (not shown) grasps the workpiece through the process as described above, the rotary member 30). For this, when power is applied to an electric motor (not shown) of the rotary driving means connected to the connecting disk 90, the rotational force of the electric motor is transmitted to the connecting disk 90 through a power transmitting member So that the connecting disk 90 and the rotating member 30 coupled thereto are rotated at a high speed. The outer bearing unit 80 disposed outside the rotary member 30 supports the load in the radial direction from the outer side of the rotary member 30 so that the rotary member 30 is stable in the inside of the housing 10 As shown in FIG.

The clamping block 40 and the clamping plate 50 are separated from each other and the linear movement of the coaxial shaft 20 and / The inner bearing unit 70 moves forward to release the fixed state of the workpiece while the chuck (not shown) is separated from the workpiece (not shown).

Meanwhile, power is continuously supplied to the clamping block 40 while the rotary member 30 rotates at a high speed, thereby generating a lot of heat in the clamping block 40.

11 and 12, an impeller 100 for blowing air toward the clamping plate 50 is installed at the rear end of the rotary member 30 together with the rotary member 30, Each of the clamping plate 50 and the clamping block 40 is formed with a plurality of ventilation holes 58 and 48 through which the air blown by the impeller 100 passes to allow the clamping block 40 to be cooled It is possible.

The impeller 100 has a structure in which a plurality of blades 102 are arranged at regular intervals in a circumferential direction on a body 101 of a circular ring shape and fixed to a rear end of the rotary member 30 And acts to blow air while rotating at high speed together with the rotary member 30. [

A plurality of air inlets (15) and air outlets (16) are formed in the housing (10) so that air blowing by the impeller (100)

The shaft driving apparatus according to this embodiment blows air while the impeller 100 rotates together when the rotary member 30 rotates at a high speed and the blown air flows through the air hole 58 of the clamping plate 50 and the clamping plate 50 Is supplied to the clamping block 40 through the vent holes 48 of the block 40 to cool the clamping block 40 and to be discharged to the outside through the air outlet 16. [ Therefore, there is an advantage that the heat generation of the clamping block 40 can be suppressed.

As described above, in the shaft driving apparatus of the present invention, the linear driving unit is responsible for linearly moving the coaxial shaft 20 to the set position, and the separate clamping operation for transmitting the second strong gripping force is performed by the clamping block 40 And the clamping plate 50 are responsible for the dual shaft drive system.

An inner bearing unit 70 which is linearly coupled with the coaxial shaft 20 in the housing 10 supports the thrust generated by the linear movement of the coaxial shaft 20 and is disposed outside the rotary member 30 The outer bearing unit 80 can stably bear the radial load caused by the rotation of the rotary member 30 at a high speed.

On the other hand, although the above-described electric axis driving apparatus provides a large clamping force through the clamping block 40, when the present invention is applied to an apparatus in which a large clamping force is not required, the operation of the clamping block 40 is omitted, ) Or, if necessary, the maximum torque may be used to secure the clamping force on the workpiece of the chuck.

And since the chuck rotating at high speed grasps the workpiece, if the power suddenly goes down, the workpiece may be scattered if the clamping force drops. Therefore, even if an emergency such as a sudden power outage occurs, a power supply unit using a battery or a supercapacitor is configured to supply power to the clamping block 40 for a predetermined period of time, thereby rotating the rotating member 30 and the spindle It is preferable that the chuck can grasp the workpiece continuously.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention as defined by the appended claims. And it is to be understood that such modified embodiments belong to the scope of protection of the present invention defined by the appended claims.

10: housing 15: air inlet
16: air outlet 20:
21: thread 30: rotating member
32: keyway 40: clamping block
41: stator iron core 42: coil
43: Slot 44: flange portion
45: anti-rotation member 50: clamping plate
51: rotation preventing groove 52: bolt fastening hole
55: guide boss 56: female threads
61: first electric motor 62: drive gear
63: driven gear 70: inner bearing unit
71: Inner bearing 72: Inner bearing housing
73: key 75: drawbar joint
80: outer bearing unit 90: connecting disk
D: Drawbar

Claims (12)

A housing (10);
A linear coaxial shaft 20 installed on the housing 10 so as to extend along the longitudinal direction of the housing 10 and linearly move in the axial direction while rotating and having threads 21 formed on the outer circumferential surface thereof;
A clamping block 40 installed in the housing 10 for generating a magnetic field by an external power source;
The clamping block 40 is installed on one side or both sides of the clamping block 40 so as to be movable only in the longitudinal direction with respect to the housing 10 and is moved toward and attached to the clamping block 40 by a magnetic field generated in the clamping block 40 A clamping plate 50 made of a magnetic material;
A guide boss 55 fixedly installed at a central portion of the clamping plate 50 and having an inner thread surface formed with a female thread 56 which is linearly engaged with the thread 21 of the coaxial shaft 20;
A driving block (65) connected to the linear shape through the coaxial shaft (20) and rotating linearly with the coaxial shaft (20);
A linear driving unit for generating a linear movement of the coaxial shaft 20 and an axial linear movement of the driving block 65 by transmitting a rotational force to the driving block 65 to rotate the driving block 65;
A rotary member 30 installed on the inside of the housing 10 so as to be linearly spaced apart from the outer circumferential surface of the coaxial shaft 20 and configured to rotate with respect to the housing 10;
The linear type linear motor is coupled between the coaxial shaft 20 and the rotary member 30 and is linearly coupled to the outer surface of the coaxial shaft 20 to linearly move with respect to the rotary member 30 together with the coaxial shaft 20, A unit 70;
An outer bearing unit 80 provided between the inner peripheral surface of the housing 10 and the outer peripheral surface of the rotary member 30 and rotatably supporting the rotary member 30 with respect to the housing 10;
And a rotation driving means coupled to a front end portion of the rotary member to rotate the rotary member with respect to the housing and the linear member with respect to the coaxial shaft. The apparatus of claim 1, further comprising: an impeller (100) installed at a rear end of the rotary member (30) and rotating together with the rotary member (30) to blow air toward the clamping plate (50)
Wherein each of the clamping plate (50) and the clamping block (40) is formed with a plurality of air holes (58, 48) through which the air blown from the impeller (100) passes. The internal bearing (70) according to claim 1, wherein the inner bearing unit (70) comprises a plurality of inner bearings (71) whose inner ring is coupled to the coaxial shaft (20) And an inner bearing housing (72) slidably connected to the inner peripheral surface of the inner bearing housing in an axial direction. The sliding bearing according to claim 3, wherein a keyway (32) is formed on the inner circumferential surface of the rotary member (30) so as to extend in the axial direction and a key (73) slidably connected to the inner bearing housing and an electric motor for driving the electric motor. The stator according to claim 1, wherein the clamping block (40) comprises: a stator core (41) fixed to the inside of the housing (10); a coil wound around the stator core (41) (42). ≪ / RTI > The clamping block according to claim 5, wherein a plurality of slots (43) through which the coil (42) is wound are formed on both sides of the clamping block (40), and the coils (42) wound on both sides of the clamping block Wherein a magnetic field is selectively generated on both sides of the clamping block (40) by applying power thereto. The linear drive unit according to claim 1, wherein the linear drive unit comprises an electric motor (61), a drive gear (62) connected to the shaft of the electric motor (61) and rotated by an electric motor (61) And a driven gear (63) engaged with the driving gear (62) and rotated by receiving power from the driving gear (62) and fixed to the driving block (65) at a central portion. 2. The motor according to claim 1, wherein the linear peripheral portion of the coaxial shaft (20) and the central portion of the driving block (65) through which the linear coaxial shaft (20) passes are connected to each other by a spline groove and a spline projection inserted into the spline groove Characterized in that the electric motor is driven by a motor. The apparatus according to claim 1, wherein, in the event of an emergency situation in which the power is cut off due to a sudden power failure during the machining operation while the rotary member (30) is rotating, the rotary member (30) Further comprising a power supply unit for supplying power to the clamping block (40) to maintain the attached state between the clamping block (40) and the clamping plate (50). (a) The linear drive unit is operated to advance the drive block 65 and the linear coaxial shaft 20 in one direction so that the linear coaxial shaft 20 is advanced to the set position and a machining chuck connected to the inner bearing unit 70 is lifted ;
(b) By actuating the linear drive unit in the reverse direction and rotating the drive block 65 and the linear diaphragm 20 in a direction opposite to the previous one, the linear diaphragm 20 is moved back to the set position, Grasping the workpiece while being pinched;
(c) machining the workpiece by rotating the rotary member (30) at a predetermined speed by operating the rotary drive means (10). The apparatus according to any one of claims 1 to 9, Lt; / RTI > 11. The method of claim 10, wherein between step (b) and step (c), power is applied to the clamping block to cause the clamping plate to move back toward the clamping block by a magnetic force, 50) is attached to the clamping block (40) so that the linear further moves the coaxial shaft (20) further backward by a certain distance. 12. The method according to claim 11, further comprising the steps of: supplying power to the clamping block (40) until the rotating member (30) is stopped when an emergency situation occurs in which power is cut off due to a sudden power failure during the step So as to maintain the state of attachment between the clamping block (40) and the clamping plate (50).

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