JP2002176763A - Drive for linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cogging without increasing the yawing of a movable body. SOLUTION: This linear motor driving device comprises a stationary body 22 having a guiding mechanism 23, the movable body 21 capable of moving along a prescribed reference surface P guided by the guiding mechanism 23, parallel rows 30, 31 of the first magnets attached at the stationary body 22 and disposed in parallel at the both sides of the reference surface P, and parallel row 26, 27 of the second magnets attached to the movable body 21 and disposed in parallel at both sides of the reference surface P. The parallel rows 30, 31 of the first magnets are made-symmetric with regard to the reference surface P, a steel plate 40 parallel with the reference surface P is provided at the crossing part of the reference surface P of the movable body 21 with the rows, and the steel plate 40 is formed into a tapered shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor driving device, and more particularly to a linear motor driving device applicable between a fixed body and a movable body of a precision machine.

[0002]

2. Description of the Related Art In order to linearly feed a movable body such as a work table or a spindle base to a fixed body such as a machine frame of a precision processing machine, a combination of a ball screw and a nut is used in place of a feed drive unit. A linear motor driving device in which a linear motor is constituted by a row of magnets arranged on a body and a row of magnets arranged on a movable body, and the movable body is fed and driven by the electromagnetic force of the linear motor has been studied.

[0003] The movable body of such a linear motor drive device is guided by a guide mechanism provided on a fixed body, and therefore moves along a design reference plane of the guide mechanism, for example, a center plane which bisects the guide mechanism to the left and right. Mobile.

For this reason, a linear motor driving device in which magnets constituting a linear motor are arranged in parallel on both sides of the reference plane has been considered.

[0005]

Therefore, it is one research subject to find out what kind of magnet arrangement is effective.

On the other hand, the movable body of the linear motor driving device
Linear motion tends to be accompanied by cogging (breathing motion in the direction of travel) and yawing (fluctuation to the left and right), and reduction of these is another research topic.

A method of reducing the cogging of the movable body by shifting the magnet arrangement position by a half pitch on the left and right sides of the reference plane has already been studied.

[0008] However, this method has a problem that yawing increases even if cogging is reduced.

It is another research subject to devise a configuration of the guide mechanism in order to stabilize the movement of the movable body.

An object of the present invention is to provide a linear motor drive device capable of reducing cogging without increasing yaw of a movable body.

[0011]

In order to achieve the above object, the present inventors have made the parallel rows of magnets plane-symmetric with respect to the reference plane, and provided the reference plane of the movable body at the intersection with the reference plane. Providing a parallel iron plate, tapering the iron plate, especially triangular, reduces the cogging of the movable body, and furthermore, if the iron plate is provided symmetrically at both ends in the moving direction of the movable body, cogging is more clearly reduced, It has been found that these effects can be obtained regardless of whether the row of magnets attached to the fixed body is a row of electromagnets or a row of permanent magnets.

In this regard, the invention according to claim 1 is a fixed body having a guide mechanism, a movable body guided by the guide mechanism and movable along a predetermined reference plane, and the reference body attached to the fixed body. A linear motor drive device comprising: a parallel row of first magnets arranged in parallel on both sides of a surface; and a parallel row of second magnets attached to the movable body and arranged in parallel on both sides of the reference plane. The parallel row of the first magnets is plane-symmetric with respect to the reference plane, and an iron plate parallel to the reference plane is provided at an intersection of the movable body with the reference plane, and the iron plate is tapered. Features.

According to the present invention, the iron plate parallel to the reference plane is provided at the intersection of the movable body and the reference plane, and the iron plate is tapered, so that the cogging of the movable body is reduced as is apparent from the above finding. Is done. Moreover, since the parallel rows of the first magnets are plane-symmetric with respect to the reference plane, yawing is reduced.

According to a second aspect of the present invention, in the linear motor driving device according to the first aspect, the iron plate has a triangular shape.

According to the present invention, the cogging of the movable body is clearly reduced as is apparent from the above finding.

According to a third aspect of the present invention, in the linear motor driving device according to the first aspect, the iron plate is provided symmetrically at both ends in the moving direction of the movable body.

According to the present invention, cogging of the movable body is more clearly reduced as is apparent from the above finding.

According to a fourth aspect of the present invention, in the linear motor driving device according to any one of the first to third aspects, the first magnet comprises an electromagnet and the second magnet comprises a permanent magnet. Features.

According to the present invention, cogging of the movable body is reduced as is apparent from the above finding.

According to a fifth aspect of the present invention, in the linear motor driving device according to any one of the first to third aspects, the first magnet comprises a permanent magnet and the second magnet comprises an electromagnet. Features.

According to the present invention as well, cogging of the movable body is reduced as is apparent from the above finding.

According to a sixth aspect of the present invention, in the linear motor driving device according to any one of the first to fifth aspects, the guide mechanism includes a pair of V-grooves symmetrical with respect to the reference plane.
It is characterized by comprising rolling bearings arranged in grooves.

According to the present invention, the movement of the movable body is stabilized.

[0024]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows an ultra-precision processing machine for processing a mold for an aspherical lens, and the linear motor driving device according to the present invention is applied to this ultra-precision processing machine.

The ultra-precision processing machine has a bed 2 on a base 1.
And the bed 2 has a tool-side bed 2 in the X direction.
A is formed, and the work-side bed member 2B in the Z-axis direction is attached.

The slider 3 is attached to the bed 2A on the tool side by X.
A column 4 is provided on the slider 3, and a spindle table 5 is mounted on the column 4.
The spindle table 5 is provided so as to be movable in the axial direction. The spindle table 5 has a spindle 6, and a cutting tool, a grinding tool, and the like are attached to the spindle 6. The drive of the spindle base 5 in the Y-axis direction is performed by a feed screw mechanism linked with the Y-axis servomotor 7.

A work table 8 is provided on the work-side bed member 2B so as to reciprocate linearly in the Z-axis direction. A rotary headstock 9 is fixed to the worktable 8, and the rotary headstock 9 grips the work with a chuck. Having a rotating shaft 10,
The rotating shaft 10 is driven to rotate by a C-axis servo motor 11.

The linear motor driving device according to the present invention comprises:
The tool-side bed portion 2A or the work-side bed member 2
B is used as a fixed body, and the slider 3 or the work table 8 is used as a movable body. Hereinafter, the embodiment will be described in common with reference to FIGS. For the sake of common description, the slider and the work table 8 are referred to as a movable body 21, and the tool-side bed 2A and the work-side bed member 2B are referred to as a fixed body 22.

On the upper surface on both left and right sides of the fixed body 22, a finite rolling bearing guide type V which is formed symmetrically with respect to one design reference plane (virtual center plane) P of the linear motor drive device.
A groove-shaped lower guide portion is provided, and a V-shaped upper guide portion symmetrical with respect to the reference plane P is provided on the lower surface on both left and right sides of the movable body 21, and the upper guide portion is engaged with the lower guide portion. The guide mechanism 23 constitutes the movable body 21.
Is guided so as to be able to reciprocate linearly.

A coil mount member 24 is fixed to the center of the lower bottom of the movable body 21 and hangs down. A plurality of pairs of left and right electromagnetic coils 26 are provided on both left and right sides of the coil mount member 24 via cooling jackets 25, respectively. , 27 are mounted and arranged parallel to each other and symmetrically with respect to the reference plane P.

The fixed body 22 includes a magnet mounting member 2 having a groove-shaped cross section.
8 is fixed integrally. The mounting member 28 has a bottom 2
The lower surfaces of the protruding portions 28B provided at equal intervals on 8A are seated on the upper surface 22A of the fixed body 22 and fastened with bolts 29, respectively. A plurality of pairs of left and right permanent magnets 30, 31 are mounted on the inner wall surfaces of the left and right side portions 28C, 28D of the mounting member 28 in parallel and symmetrically with respect to the reference plane P. Movable body 2
A pair of rows of electromagnetic coils 26, 27 mounted on 1
It moves along the reference plane P between a pair of rows of the permanent magnets 30 and 31 attached to the fixed body 22. Note that a pair of rows of the electromagnetic coils 26 and 27 and the permanent magnets 30 and 3
In this embodiment, one pair of rows has the same pitch, but another pitch may be used.

In the above configuration, the left electromagnetic coil 26
And the row of the permanent magnets 30 on the left side constitute the first linear motor 32 on the left side, and the row of the electromagnetic coils 27 on the right side and the row of the permanent magnets 31 on the right side constitute the second linear motor 33 on the right side. You. Therefore, the first linear motor 32 and the second linear motor 33 are parallel to each other and symmetric with respect to the reference plane P.

As shown in FIG. 4, the permanent magnet 30 of the first linear motor 32 and the permanent magnet 31 of the second linear motor 33
Has the N pole 34 and the S pole 35 alternately. These permanent magnets 30 and 31 are bilaterally symmetrical with respect to the reference plane P, and there is no shift in their mutual arrangement positions. The electromagnetic coil 26 of the first linear motor 32 and the electromagnetic coil 27 of the second linear motor 33 have a U pole, a V pole, and a W pole in the reverse order. The poles-V poles are symmetrical with respect to the reference plane P, and there is no deviation in their mutual arrangement positions.

The tapered shape parallel to the reference plane P (specifically, an isosceles triangular shape in a side view) is formed at the intersection between the both ends in the moving direction of the movable body 21 (that is, the front and rear ends) and the reference plane P. ) Is provided symmetrically in the front-rear direction.

According to this embodiment, the front and rear iron plates 40
The cogging of the movable body 21 is reduced by the electromagnetic action of
Further, the yaw of the movable body 21 is reduced by the symmetry of the left and right linear motors 32, 33.

Since the linear motion guide mechanism 23 is constituted by a VV finite rolling guide, a higher rigidity can be obtained than in the case of the static pressure guide, and precise feed can be performed with a high precision feed resolution. Will be. Electromagnetic coils 26, 27
Is a coil moving type on the movable body 21 side, the thrust of the first linear motor 32 and the second linear motor 33 always acts on the fixed point of the movable body 21, and the movement accuracy of the movable body 21 is stabilized.

Therefore, the ultra-precision machining required for machining the mold for the aspheric lens can be performed.

FIG. 5 shows a linear motor driving apparatus according to another embodiment of the present invention. Portions corresponding to the above-described embodiments are denoted by the same reference numerals, and description thereof is omitted.

In this embodiment, the electromagnetic coils 26 and 27
Is mounted on the fixed body 22 side, and the mounting member 28 and the permanent magnets 30 and 31 are mounted on the movable body 21 side.

According to this embodiment, the same operation and effect as those of the above-described embodiment can be obtained.

[0042]

As will be understood from the above description, according to the linear motor driving apparatus of the present invention, there is provided a linear motor driving apparatus capable of reducing cogging without increasing yaw of a movable body. . That is, not only the cogging is reduced as discovered by the inventors, but also the left and right components of the magnetic attraction force are canceled out due to the symmetry of the two sets of linear motors, the periodic yawing phenomenon is reduced, and the movable body is reduced. Does not meander at the magnetic pole pitch. Thereby, the straightness of the movable body is improved, and the processing accuracy is improved.

According to the linear motor drive device of the present invention, since the linear motion guide member is a VV finite type rolling guide, higher rigidity can be obtained than in the case of the static pressure guide, and high precision can be obtained. Precise feeding by the feed resolution is performed, and machining accuracy is improved.

[Brief description of the drawings]

FIG. 1 is a front view of an ultraprecision processing machine for processing a die for an aspherical lens to which a linear motor driving device according to the present invention is applied.

FIG. 2 is a side view of the linear motor driving device according to the embodiment of the present invention.

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a schematic plan view of the linear motor driving device of FIG. 2;

FIG. 5 is a sectional view of a linear motor driving device according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 2 Bed member 2A Tool side bed part 2B Work side bed member 3 Slider 4 Column 5 Spindle stand 8 Work table 9 Rotation stand 21 Movable body 22 Fixed body 23 Guide mechanism 26, 27 Electromagnetic coil 28 Attachment member 30, 31 Permanent magnet 32 First linear motor 33 Second linear motor 40 Iron plate P Reference plane

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Katsuharu Kakuhari 2068-3 Ooka, Numazu-shi, Shizuoka F-term (reference) 5H641 BB06 BB14 BB18 GG03 GG04 GG07 GG12 HH02 HH09 HH17 JA09

Claims (6)

[Claims] 1. A fixed body having a guide mechanism, a movable body guided by the guide mechanism and movable along a predetermined reference plane, and mounted on the fixed body and arranged in parallel on both sides of the reference plane. A linear motor driving device comprising: a parallel row of first magnets; and a parallel row of second magnets attached to the movable body and arranged in parallel on both sides of the reference plane, wherein the parallel row of the first magnets is provided. Is linearly symmetrical with respect to the reference surface, and an iron plate parallel to the reference surface is provided at an intersection of the movable body with the reference surface, and the iron plate is tapered. 2. The linear motor driving device according to claim 1, wherein the iron plate has a triangular shape. 3. The linear motor driving device according to claim 1, wherein the iron plates are provided symmetrically at both ends in the moving direction of the movable body. 4. The linear motor driving device according to claim 1, wherein said first magnet is made of an electromagnet, and said second magnet is made of a permanent magnet. apparatus. 5. The linear motor driving device according to claim 1, wherein the first magnet is made of a permanent magnet, and the second magnet is made of an electromagnet. apparatus. 6. The linear motor driving device according to claim 1, wherein the guide mechanism includes a pair of V-grooves symmetrical with respect to the reference plane and a rolling bearing arranged in the V-groove. A linear motor drive device comprising: