JP2005192322A - Linear synchronous motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear synchronous motor which is improved in motor constants and robustness. <P>SOLUTION: The linear synchronous motor of this invention comprises an external yoke 10; a center yoke 5 arranged movably along the axial line of the external yoke inside the external yoke 10; a permanent magnet group 4 comprising a plurality of permanent magnets arranged on upper and lower outer peripheries of the center yoke and each fitted and attached to the sides facing the inner surface of the external yoke 10 along the longitudinal direction; and an annular electromagnet coil group 3 that surrounds the center yoke 5 and that is attached to the inside peripheral surface of the external yoke 10. The permanent magnet group 4 mounted on the center yoke 5 moves against the electromagnet coil group 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a linear synchronous motor.
In particular, the present invention relates to a linear synchronous motor that has high rigidity, small thrust fluctuation, and can be reduced in size and weight.
The present invention also relates to a linear synchronous motor useful for vibration isolation, fine vibration control of a vibration damping device, and positioning with nanometer unit superprecision.

  Linear synchronous motors are used in machine tools, semiconductor manufacturing apparatuses, and the like that require a large thrust. For example, application examples of the linear synchronous motor include vibration isolation, fine vibration control of a vibration damping device, and positioning with ultra-precision in nanometer units.

As a linear synchronous motor suitable for such a use, it describes in Unexamined-Japanese-Patent No. 2002-238240, for example.
A linear synchronous motor described in Japanese Patent Laid-Open No. 2002-238240 includes an external yoke, and a plurality of permanent magnets in which N poles and S poles are alternately arranged on the inner wall of the external yoke along the axial direction of the external yoke. The reinforcing plate has a reinforcing plate movable along the axial direction of the outer yoke, and a three-phase coil disposed on the reinforcing plate so as to face the plurality of permanent magnets. In the longitudinal direction of the external yoke, the plurality of permanent magnets and the three-phase coil are arranged in a predetermined positional relationship. The reinforcing plate and the three-phase coil mounted on the reinforcing plate constitute a movable part that moves in the external yoke. In such a linear synchronous motor, when a current is passed through the three-phase coil, the movable part moves in the outer yoke in the axial direction due to the interaction between the electromagnetic force generated by the three-phase coil and the magnetic force of the permanent magnet. Move along. The moving speed of the moving part changes according to the magnitude of the current applied to the three-phase coil, and the moving amount of the moving part is defined according to the time during which the current is applied to the three-phase coil. The direction of movement of the movable part changes depending on the direction of the current to be generated.

However, the linear synchronous motor described in Japanese Patent Application Laid-Open No. 2002-238240 has the following disadvantages.
(1) Since the reinforcing plate of the movable part is flat and thin in order to reduce weight, the torsional rigidity is low, and micro vibrations are likely to occur in the movable part.
(2) The speed of the movable part and the current position vary due to the slight vibration generated in the movable part. Such fluctuations are fed back via the position sensor, and the vibration is further amplified. Therefore, the control gain is lowered, and it is difficult to control in nanometer units.
(3) When the output increases, heat generation increases, and as a result, the ambient temperature rises, and errors due to thermal expansion are likely to occur.
JP 2002-238240 A

Various attempts have been made to overcome the above disadvantages.
However, it is further desired that the rigidity is small, the thrust fluctuation is small, the size and the weight can be reduced, the motor constant and the robustness can be improved, and the ultraprecision control can be easily performed. Although provision of a linear synchronous motor is desired, it has not been achieved yet.

An object of the present invention is to provide a linear synchronous motor that achieves the above-described demand.
That is, an object of the present invention is to provide a linear synchronous motor that has high rigidity, small thrust fluctuation, and can be reduced in size and weight.
Another object of the present invention is to provide a linear synchronous motor that can improve motor constants and robustness.
A further object of the present invention is to provide a linear synchronous motor useful for vibration isolation, fine vibration control of a vibration damping device, and positioning with nanometer unit ultra-precision.

According to the present invention, the outer yoke has an annular shape with a hollow cross section, and is inserted and fixed in the outer yoke, and the inside of the electromagnet coil group is hollow in the longitudinal direction of the outer yoke. A center yoke disposed so as to be movable in a direction, and a permanent magnet group disposed on opposite sides in one direction of the cross section of the center yoke so as to face the electromagnet coil group,
The permanent magnet group includes a plurality of permanent magnets alternately arranged with different magnetic poles in the longitudinal direction of the center yoke, and the same magnetic poles on both sides at the same position in the longitudinal direction of the center yoke,
The electromagnet coil group includes a plurality of electromagnet coils arranged in a predetermined positional relationship with the plurality of permanent magnets in a longitudinal direction of the center yoke,
The predetermined positional relationship and the current applied to the plurality of electromagnet coils are set as synchronization conditions,
A linear synchronous motor in which the center yoke and the plurality of permanent magnets move in the external yoke in a synchronized state by thrust of electromagnetic force that interacts between the electromagnet coil group and the permanent magnet group. Provided.

In the first form of the linear synchronous motor of the present invention,
A unit of a plurality of coils constituting the electromagnet coil group is a first coil to which a first-phase positive-phase alternating current is applied, which is disposed at a position angle of 3π / 4 (radian). A second coil to which an alternating current of the negative phase of the first phase is applied, and a positive current of the second phase having a π (radian) phase difference from the positive phase alternating current of the first phase. Is constituted by a third coil to which is applied, and a fourth coil to which an alternating current of the opposite phase of the second phase is applied,
One unit of a plurality of permanent magnets constituting the permanent magnet group is three permanent magnets arranged at a position angle of π (radian) on both sides of the center yoke in the longitudinal direction of the center yoke. It is configured.

In the first form of the linear synchronous motor of the present invention, the following currents Ia, Ib, Ic, and Id are respectively applied to a plurality of coils constituting one unit of the electromagnet coil group.
Ia = Im × cos (ωt)
Ib = −Im × cos (ωt)
Ic = Im × sin (ωt)
Id = −Im × sin (ωt)
Here, Im is the maximum current amplitude.

In the second form of the linear synchronous motor of the present invention,
A unit of a plurality of coils constituting the electromagnet coil group is a first coil to which a first-phase positive-phase alternating current is applied, which is disposed at a position angle of 3π / 4 (radian). A second coil to which an alternating current of the negative phase of the first phase is applied, and a positive alternating current of the second phase having a first phase difference from the positive alternating current of the first phase. A third coil to be applied; a fourth coil to which a second-phase alternating current is applied; and a third phase having a second phase difference from the positive-phase alternating current of the first phase. And a sixth coil to which a positive-phase alternating current is applied and a sixth coil to which a third reverse-phase alternating current is applied,
One unit of the plurality of permanent magnets constituting the permanent magnet group is four permanent magnets arranged at a position angle of π (radian) on both sides of the center yoke in the longitudinal direction of the center yoke. It is configured.

In the second form of the linear synchronous motor of the present invention, the following currents IUa, IUb, IWa, IWb, IVa, and IVb are respectively applied to a plurality of coils constituting one unit of the electromagnet coil group.
IUa = Im × sin (ωt)
IUb = −Im × sin (ωt)
IWa = Im × sin (ωt + 8π / 3)
IWb = −Im × sin (ωt + 8π / 3)
IVa = Im × sin (ωt + 4π / 3)
IVb = −Im × sin (ωt + 4π / 3)
Here, Im is the maximum current amplitude.

  Preferably, the electromagnet coil group is fitted on an inner wall of the outer yoke, and heat of the electromagnet coil group is radiated through the outer yoke.

  Preferably, the cross-sectional shape of the outer yoke is a rectangle, and the cross-sectional shape of the center yoke is a rectangle.

  The linear synchronous motor of the present invention is formed in an annular shape so that the electromagnet coil group is fitted in the external yoke, and the electromagnet coil group formed in an annular shape is fitted and fixed inside the external yoke. Therefore, the torsional rigidity of the electromagnet coil group is increased. In addition, the fluctuation in thrust is reduced, which makes ultra-precision control easier and improves motor constants and robustness.

  In the linear synchronous motor of the present invention, since the adjacent electromagnet coils are arranged with opposite polarities, the dynamic magnetic fluxes from the respective phase coils cancel each other, and eddy currents generated in the external yoke are almost eliminated, and iron The loss could be significantly reduced.

  In the linear synchronous motor of the present invention, since the electromagnet coil group is fixed to the external yoke, heat is radiated through the external yoke, and the influence of heat can be reduced. In other words, the cooling measures for the electromagnet coil group are easy, and the thermal expansion of the linear synchronous motor can be suppressed.

In the linear synchronous motor of the present invention, the shape of the permanent magnet group fixed to the center yoke is compact, and the center yoke can be made large. Therefore, the rigidity of the center yoke can be increased. As a result, fixing of the permanent magnet group to the center yoke is stable.
In addition, since the center yoke and the permanent magnet group are easy to move as compared with the case where the electromagnet coil group is fixed to the center yoke, high-speed operation is possible.

  Since the electromagnet coil group is fitted with the external yoke and does not move, it is easy to wire the current application wire to the electromagnet coil group. In other words, the linear synchronous motor of the present invention has no problem of supplying power to the movable part.

  The linear synchronous motor of the present invention is small.

  Hereinafter, preferred embodiments of a linear synchronous motor according to the present invention will be described with reference to the accompanying drawings.

First Embodiment A first embodiment of a linear synchronous motor according to the present invention will be described with reference to FIGS. 1 (A) to (C), FIG. 2 and FIG.
1A to 1C are respectively a schematic sectional view of a linear synchronous motor according to a first embodiment of the present invention, a sectional view taken along line BB in FIG. 1A, and FIG. It is an arrow directional cross-sectional view in line AA.
FIG. 2 is a perspective view of the coil illustrated in FIG.
FIG. 3 is a diagram showing the arrangement of permanent magnets and coils illustrated in FIG.

[Structure of linear synchronous motor]
First, the structure of the linear synchronous motor 1 will be described.
The linear synchronous motor 1 has an external yoke 10 and a center yoke 5.
The linear synchronous motor 1 further includes an electromagnet coil group 3 fitted on the inner wall of the external yoke 10 and a permanent magnet group 4 mounted on the top and bottom of the center yoke 5.
The center yoke 5 constitutes a magnetic circuit with the electromagnet coil group 3 and the permanent magnet group 4 and is therefore made of a magnetic material.

The outer yoke 10 has a rectangular cross section and extends in a cylindrical shape in the longitudinal direction. Both end portions are provided with side yokes 100 a and 100 b, and the inside constitutes a lumen 9. The inner cavity 9 accommodates the electromagnet coil group 3 and allows the center yoke 5 and the permanent magnet group 4 to move.
In cross section, the outer yoke 10 includes an upper yoke 10A, a lower yoke 10B, a left yoke 10C, and a right yoke 10D.
The side yokes 100a and 100b are provided with through holes 200a and 200b having a rectangular cross section penetrating the center yoke 5. The cross sectional areas of the rectangular through holes 200a and 200b are slightly larger than the cross sectional area of the center yoke 5. .

The cross section of the center yoke 5 is rectangular, and both ends of the center yoke 5 protrude through the through holes 200a and 200b to the outside of the external yoke 10. The center yoke 5 is pivotally supported by the portions 200a and 200b so that the center yoke 5 can reciprocate along the axial centers CC of the outer yoke 10 through the through holes 200a and 200b.
The cross sectional area of the through holes 200a, 200b is slightly larger than the cross sectional area of the center yoke 5, as described above, while the center yoke 5 is pivotally supported, the through holes 200a, 200b can be reciprocated. Because. A lubricating member or a lubricant is disposed in the through holes 200a and 200b so that the center yoke 5 can be moved smoothly.
An object (not shown) to be driven by the linear synchronous motor 1 can be connected to at least one end of the center yoke 5.

  Permanent magnet groups 4 mounted on the upper and lower sides of the center yoke 5 are arranged along the line CC along the first S-pole permanent magnets 4S1a and 4S1b, the first N-pole permanent magnets 4N1a and 4N1b, and the second S-pole permanent magnets 4S2a and 4S2b. As shown in FIG. That is, permanent magnets having the same magnetic pole, for example, first S-pole permanent magnets 4S1a and 4S1b are arranged above and below the same position of the center yoke 5 in the line CC direction of the center yoke 5, and extend along the line CC direction. Permanent magnets having different magnetic poles, for example, first S-pole permanent magnets 4S1a and 4S1b and first N-pole permanent magnets 4N1a and 4N1b are alternately arranged.

As illustrated in FIG. 2, the electromagnet coil 3 includes non-magnetic insulating members 31 a to 31 c along the longitudinal direction (CC direction) of the outer yoke 10, and the coils 3 A 1, 3 A 2, 3 B 1, and 3 B 2 are non-magnetic insulating members 31 a to 31 c. The center portion is formed in a hollow 32 state in which the center yoke 5 and the permanent magnet group 4 attached to the center yoke 5 can move.
The coil 3A1, the coil 3A2, the coil 3B1, and the coil 3B2 are formed in a rectangular ring shape so that they can be fitted to the inner wall of the outer yoke 10, and the same specification, for example, a conductive wire such as an enamel wire is formed in a rectangular ring shape. It is formed of a multi-layer winding, and is fixed in a state in which a rectangular annular shape is maintained by infiltrating an adhesive such as an epoxy resin between the conductive wires.
As illustrated in FIGS. 1A and 1B, the electromagnet coil 3, for example, the coil 3A1, includes an inner wall 10a of the upper yoke 10A of the outer yoke 10, an inner wall 10b of the lower yoke 10B, and an inner wall 10c of the left yoke 10C. The inner wall 10d of the right yoke 10D is fitted. The other coils are similarly inserted into the outer yoke 10 and are preferably fitted to the inner wall of the outer yoke 10.

As illustrated in FIG. 3, in the permanent magnet group 4, the position angle of each of the upper and lower sets of permanent magnets is π (radians), and the permanent magnet group 4 is arranged along the longitudinal direction of the center yoke 5 starting from the permanent magnets 4S1a and 4S1b. The sum of the position angles of the three upper and lower permanent magnets provided is 3π (radian).
The broken lines illustrate the lines of magnetic force of the permanent magnets disposed on the alternating magnetic poles adjacent to the center yoke 5.
The electromagnet coil 3 is 3π (radians) with four coils 3A1, 3A2, 3B1, and 3B2. The position angle of each coil is 3π / 4 (radian). The position angles of the coils 3A1, 3A2, 3B1, and 3B2 are 3π / 4, 6π / 4, 9π / 4 (radian), and 3π (radian), respectively, starting from the permanent magnets 4S1a and 4S1b.

In FIG. 1A, as a basic form, one unit portion of the first electromagnet coil group 3 and the permanent magnet group 4, that is, four electromagnet coils 3A1: 3A2, 3B1: 3B2, Only permanent magnets 4S1a: 4S1b, 4N1a: 4N1b, 4S2a, 4S2b are illustrated.
In order to increase thrust and perform smooth movement of the center yoke 5, actually, a plurality of units of electromagnets and a plurality of units of permanent magnets are arranged along the longitudinal direction of the center yoke 5.
For example, the following currents Ia, Ib, Ic, and Id are applied to the four coils 3A1, 3A2, 3B1, and 3B2, respectively.

Ia = Im × cos (ωt)
Ib = −Im × cos (ωt)
Ic = Im × sin (ωt)
Id = −Im × sin (ωt)
Here, Im is the maximum current amplitude.
... (1)

The coil 3A1 has a positive-phase cosine wave (cos) alternating current, the coil 3A2 has a negative-phase cosine wave alternating current, the coil 3B1 has a positive-phase sine wave (sin) alternating current, and the coil 3B2 has a negative-phase sine wave. A wave alternating current is applied.
In other words, it can be said that a four-phase alternating current is applied to the coils 3A1, 3A2, 3B1, and 3B2, and 0, π, π if the cosine wave alternating current (or sine wave alternating current) is used as a reference. It can be said that a single-phase alternating current having a phase difference of / 2, 2π (radian) is applied, and that a two-phase alternating current of a cosine wave and a sine wave of positive and negative phases are applied, respectively.
Hereinafter, in this specification, it is said that a two-phase alternating current is applied.
The currents Ia, Ib, Ic, and Id need only maintain the phase difference of 0, π, π / 2, and 2π (radians). The currents Ic and Id are the cosine wave alternating current and the currents Ia and Ib are the same. A sinusoidal alternating current may be used.

  In the relationship of illustration, although the electric wire which applies an electric current to these coils 3A1, 3A2, 3B1, 3B2 is not illustrated, since the electromagnet coil group 3 does not move and is fitted to the inner wall of the external yoke 10, Since the electric wire can be wired along the inner wall of the outer yoke 10 or the outer wall of the outer yoke 10 can be penetrated, the electric current applying electric wire can be easily arranged.

  In the illustration of FIG. 1 (A), the outer yoke 10 is illustrated as being integrally formed, but in actuality, either one of the side yokes 100a and 100b is removable, and the electromagnet coil. 3 is inserted into the inner wall of the outer yoke 10 and when the center yoke 5 with the permanent magnet group 4 is inserted into the inner cavity 9 of the outer yoke 10, one of the side yokes 100a and 100b is removed. As shown in FIG. 1A, the electromagnet coil 3 is fitted on the inner wall of the outer yoke 10 and the center yoke 5 with the permanent magnet group 4 is inserted into the inner cavity 9 of the outer yoke 10. Both end sides of the outer yoke 10 are closed with the side yokes 100a and 100b.

[Operation method of linear synchronous motor]
An operation method of the linear synchronous motor 1 will be described.
FIG. 3 illustrates the upper half, but as illustrated in FIG. 1 (A), three pairs in pairs above and below the center yoke 5, a total of six permanent magnets 4S1a: 4S1b, 4N1a: 4NSb, 4S2a: 4S2b and four electromagnet coils 3A1: 3A2, 3B1: 3B2 are configured as one operation unit, and the operation of this one unit will be described.
In FIG. 3, the magnetic flux emitted from the permanent magnet 4N1a passes through the opposing electromagnet coils 3A1 and 3A2 to the left adjacent permanent magnet 4S1a and passes through the opposing electromagnet coils 3B1 and 3B2 to the right adjacent permanent magnet 4S2a. enter.
Starting from the permanent magnets 4S1a and 4S1b, the distance x in the moving direction of the center yoke 5, that is, the X-axis direction is set.
When the coils 3A1, 3A2, 3B1, and 3B2 are moved in the X-axis direction by the distance x, the flux numbers Ba, Bb, Bc, and Bd that are linked are as follows.

Ba = Bm × sin (x)
Bb = Bm × sin (x + 3π / 4)
Bc = Bm × sin (x + 6π / 4)
Bd = Bm × sin (x + 9π / 4)
Where Bm is the maximum magnetic flux density of the permanent magnet.
... (2)

  Chain of permanent magnets 4S1a: 4S1b, 4N1a: 4NSb, 4S2a: 4S2b, and currents Ia, Ib, Ic, Id flowing in the electromagnet coils 3A1: 3A2, 3B1: 3B2 shown in Equation 1 (1) The forces acting between the permanent magnet groups 4S1a: 4S1b, 4N1a: 4NSb, 4S2a: 4S2b and the electromagnet coils 3A1: 3A2, 3B1: 3B2 are as follows.

F = Ba * Ia + Bb * Ib + Bc * Ic + Bd * Id
= Bm · Im [sin (x) −sin (x + 3π / 4)] × cos (ωt)
+ Bm · Im [sin (x + 6π / 4) −sin (x + 9π / 4)]
× sin (ωt)
= 2Bm · Im · sin (-3π / 4)
× [cos (x + 3π / 8) · cos (ωt)
+ Cos (x + 15π / 8) · sin (ωt)
... (3)

  Since cos (x + 15π / 8) = sin (−3π / 8), when this is substituted, the following equation is obtained.

F = 2Bm · Im · sin (−3π / 4)
Xsin (-3 [pi] / 8) * [cos (x + (3 [pi] / 8)-[omega] t)]
= Α × sin (−3π / 8) × [cos (x + (3π / 8) −ωt)]
However, α = 2Bm · Im · sin (−3π / 4)
(4)

  When (x + (3π / 8) −ωt) = 2Nπ (N is an integer), the force F has a maximum value Fmax under the following conditions.

Fmax = 2Bm · Im · sin (−3π / 8) × sin (−3π / 8)
= 2Bm · Im · (= 1/2) [cos (−3π / 4) −1]
= Bm · Im [1-cos (3π / 4)]
(4)

  When the maximum force Fmax is differentiated with respect to time t, the following equation is obtained.

−ω + dx / dt = 0
... (5)

The phase velocity on the X axis is as follows.
dx / dt = ω.
... (6)

In the present embodiment, since the electromagnet coils 3A1: 3A2, 3B1: 3B2 are fixed, the permanent magnets 4S1a: 4S1b, 4N1a: 4NSb, 4S2a: 4S2b and the center yoke 5 move.
As a result, as long as the permanent magnets 4S1a: 4S1b, 4N1a: 4NSb, 4S2a: 4S2b move in the X-axis direction at the moving speed ω defined by the position angle, the electromagnet coils 3A1: 3A2, 3B1: 3B2 are permanent magnets. 4S1a: 4S1b, 4N1a: 4NSb, 4S2a: 4S2b means that the thrust received from the field magnetic flux is constant.

Further, the above result satisfies the condition of ωt = ± x, which is a premise of the operation of the linear synchronous motor.
Therefore, the electromagnet coils 3A1: 3A2, 3B1: 3B2 are spaced apart by 3π / 4 at the position angle, and, for example, as illustrated in the equation (1), the positions of 0, −π / 2, 2π (radians) When an alternating current having a phase difference is applied, the permanent magnet group 4 (4S1a: 4S1b, 4N1a: 4NSb, 4S2a: 4S2b) mounted on the center yoke 5 has a phase velocity defined by each frequency ω of the drive current. Move in the axial direction.
Note that the current applied to the electromagnet coils 3A1: 3A2, 3B1: 3B2 is not limited to the example of the formula (1), and may be a phase difference of π, π / 2, π (radians), for example.

[Effect of the linear synchronous motor of the first embodiment]
In the linear synchronous motor of the first embodiment, the electromagnet coil group 3 is formed in an annular shape so as to be fitted in the external yoke 10, and the electromagnet coil group 3 formed in an annular shape is formed in the outer yoke 10. Since it is fitted and fixed to the inner wall, the torsional rigidity of the electromagnet coil group 3 is increased. In addition, fluctuations in thrust were reduced, and ultra-precision control became easier, and motor constants and robustness were improved.

  Since the adjacent electromagnet coils 3A1 and 3A2, 3B1 and 3B2 are arranged with opposite polarities, the kinetic magnetic fluxes from the respective phase coils cancel each other, and eddy currents generated in the external yoke 10 are almost eliminated, and iron The loss could be significantly reduced.

  Furthermore, since the electromagnet coil group 3 is fixed to the external yoke 10, heat is radiated through the external yoke 10, and the influence of heat can be reduced. In other words, the cooling measures for the electromagnet coil group 3 are easy, and the thermal expansion of the linear synchronous motor can be suppressed.

The shape of the permanent magnet group 4 fixed to the center yoke 5 is compact, and the center yoke 5 can be made larger than when the electromagnet coil group 3 is mounted on the center yoke 5. Therefore, the rigidity of the center yoke 5 can be increased. As a result, the fixing of the permanent magnet group 4 to the center yoke 5 is stable.
Further, compared to the case where the electromagnet coil group 3 is fixed to the center yoke 5, the center yoke 5 and the permanent magnet group 4 are easy to move, so that high speed operation is possible.

  Since the electromagnet coil group 3 is fitted and fixed to the inner wall of the external yoke 10 and does not move, it is easy to wire a current application wire to the electromagnet coil group 3. For example, in the linear synchronous motor described in Japanese Patent Application Laid-Open No. 2002-238240, since the coil is mounted on the reinforcing plate of the movable part, it is difficult to wire the current application wire for supplying current to the coil. . On the other hand, in the embodiment of the present invention, the movable part is the center yoke 5 and the permanent magnet group 4 attached to the center yoke 5, and it is not necessary to apply a current to the permanent magnet group 4. There is no problem of feeding power to the moving part.

  The structure of the linear synchronous motor 1 is compact, there is no problem of the wiring of the electric current application wire, and the linear synchronous motor is small.

Second embodiment

A second embodiment of the linear synchronous motor of the present invention will be described with reference to FIGS. 4 (A) to (C), FIG. 5 and FIG.
In the second embodiment, what is not particularly described is the same as that of the first embodiment.
4A to 4C are schematic sectional views of the linear synchronous motor according to the second embodiment of the present invention, sectional views taken along line BB in FIG. 4A, and FIG. It is an arrow directional cross-sectional view in line AA.
FIG. 5 is a perspective view of the coil illustrated in FIG.
FIG. 6 is a diagram showing the arrangement of permanent magnets and coils illustrated in FIG.

[Structure of linear synchronous motor]
4A to 4C, the linear synchronous motor 1A according to the second embodiment of the present invention is cylindrical, and is movable in the outer yoke 10 along the axis of the outer yoke 10. A plurality of center yokes 5 arranged and fixed to the side of the upper outer periphery of the center yoke 5 that faces the inner surface 10a of the upper yoke 10A disposed at the upper position of the outer yoke 10 along the longitudinal direction. Upper permanent magnets S1a, N1a, S2a, N2a,... On the lower outer periphery of the center yoke 5 and on the side facing the inner surface 10b of the lower yoke 10B disposed at the lower position of the outer yoke 10 in the figure. A plurality of lower permanent magnets S1b, N1b, S2b, N2b,..., And annular first and second three-phases surrounding the center yoke 5 and fixed to the inner peripheral surface of the outer yoke 10. Yl 6a, and a 6b.

The upper permanent magnets S1a, N1a, S2a, N2a,... And the lower permanent magnets S1b, N1b, S2b, N2b,... Are arranged so that the same polarity permanent magnets face each other on the same vertical line. For example, the first S pole / N pole upper permanent magnet S1a / N1a and the first S pole / N pole lower permanent magnet S1b / N1b are arranged to face each other.
Further, the upper permanent magnets S1a, N1a, S2a, N2a,... Are arranged so that the polarities of the permanent magnets having different polarities are alternately arranged along the longitudinal direction of the center yoke 5, that is, S poles, N poles. ,... Are arranged alternately with the S poles. Similarly, the lower permanent magnets S1b, N1b, S2b, N2b,... Are arranged so that permanent magnets having different magnetic polarities are alternately arranged along the longitudinal direction of the center yoke 5, for example, S pole, N pole, ... It is arranged so as to be the S pole.

  The center yoke 5 is formed in a substantially rectangular shape in a cross-sectional view, together with the integrated upper permanent magnets S1a, N1a, S2a, N2a,... And the lower permanent magnets S1b, N1b, S2b, N2b,. It is configured to move in the X direction.

As shown in FIG. 5, the first three-phase coil 6a includes, for example, a U-phase coil 6Ua, a W-phase coil 6Wa, and a V-phase coil 6Va formed in a rectangular ring shape. These U-phase coils 6Ua, Each of the W-phase coil 6Wa and the V-phase coil 6Va is formed by winding a conductive wire such as an enameled wire in a rectangular ring shape with the same specifications, and a rectangular shape by infiltrating an adhesive such as an epoxy resin between the conductive wires. It is fixed in a state where an annular shape is maintained.
Similarly, the second three-phase coil 6b includes, for example, a -U phase coil 6Ub, a -W phase coil 6Wb, and a -V phase coil 6Vb formed in a rectangular ring shape. These -U phase coils 6Ub, The -W-phase coil 6Wb and the -V-phase coil 6Vb are formed with the same specifications as the first three-phase coil 6a, and are fixed with an adhesive while maintaining a rectangular annular shape.
-U phase coil 6Ub, -W phase coil 6Wb, and -V phase coil 6Vb are respectively U phase coil 6Ua, W phase coil 6Wa, and V phase coil 6Va. This shows that the phase coil 6Vb is arranged.
Nonmagnetic insulating members 61a, 61b, 61c, 61d, and 61e are inserted between the coils of each phase.

  The U-phase coil 6Ua, -U-phase coil 6Ub, W-phase coil 6Wa, -W-phase coil 6Wb, V-phase coil 6Va, and -V-phase coil 6Vb constituting the first and second three-phase coils 6a and 6b are as follows: It is integrated as follows. That is, (1) the -U phase coil 6Ub of the second three-phase coil 6b is disposed adjacent to the U-phase coil 6Ua of the first three-phase coil 6a, and (2) W of the first three-phase coil 6a. The -W phase coil 6Wb of the second three-phase coil 6b is disposed adjacent to the phase coil 6Wa, and (3) -V of the second three-phase coil 6b is added to the V-phase coil 6Va of the first three-phase coil 6a. The phase coils 6Vb are arranged adjacent to each other, and (4) the coils of the respective phases are laminated in the order of the U phase, the W phase, and the V phase along the X direction with the axial centers of the hollow portions 62 aligned. Arranged in a state.

In the present embodiment, the phase order of the three-phase alternating current is set to the U phase, the W phase, and the V phase in the present embodiment in the order of the U phase coil 6U, the V phase coil 6V, and the W phase coil 6W. This is because the phase difference is set to 4π / 3.
Therefore, the U-phase coil 6Ua, -U-phase coil 6Ub, W-phase coil 6Wa, -W-phase coil 6Wb and V-phase coil 6Va, -V-phase coil 6Vb have the following currents IUa, IUb, IWa, IWb, IVa, IVb is applied.

IUa = Im × sin (ωt)
IUb = −Im × sin (ωt)
IWa = Im × sin (ωt + 8π / 3)
IWb = −Im × sin (ωt + 8π / 3)
IVa = Im × sin (ωt + 4π / 3)
IVb = −Im × sin (ωt + 4π / 3)
Here, Im is the maximum current amplitude.
... (7)

  Normally, the phase sequence of the three-phase coil is U phase, V phase, and W phase, and the phase difference is set to 2π / 3. However, in the second embodiment of the present invention, the U phase coil 6U By setting the phase difference between the V-phase coil 6V and the W-phase coil 6W to 4π / 3, the phase of the W-phase coil 6W is shifted by 2π / 3 when viewed from the U-phase coil 6U. As a result, as shown in FIG. 4, the three-phase coil 6 is arranged in the phase order of the U-phase coil 6U, the W-phase coil 6W, and the V-phase coil 6V.

In the linear synchronous motor of the second embodiment, as in the first embodiment, a so-called axial magnetic flux type excitation structure in which permanent magnets of the same polarity are arranged on the same vertical line is employed. The magnetic circuit illustrated in FIG. 6 is obtained.
(1) For example, the magnetic flux generated from the first N-pole upper permanent magnet N1a passes through the three-phase coils 6Wa and 6Ua, passes through the adjacent first S-pole upper permanent magnet S1a, and passes through the center yoke 5. To return to the original first N-pole upper permanent magnet N1a.
(2) Further, for example, the magnetic flux generated from the first N-pole lower permanent magnet N1b passes through the three-phase coils 6Wa and 6Wb, passes through the adjacent second S-pole lower permanent magnet S2b, and passes through the center yoke 5 To return to the original first N-pole lower permanent magnet N1b.

  A first three-phase coil 6a or a -U-phase coil 6Ub or a -W-phase coil 6Wb that includes a U-phase coil 6Ua, a W-phase coil 6Wa, and a V-phase coil 6Va arranged in the magnetic field of such a permanent magnet. When the three-phase alternating currents IUa, IUb, IWa, IWb, IVa, and IVb of the formula (7) are passed through the second three-phase coil 6b that includes a pair of the V-phase coil 6Vb and the coil of each phase, A thrust based on the Fleming left-hand rule is generated between the upper permanent magnets S1a, N1a, S2a, N2a,... And the lower permanent magnets S1b, N1b, S2b, N2b,. Since the coil side is fixed, the upper permanent magnets S1a, N1a, S2a, N2a,... And the lower permanent magnets S1b, N1b, S2b, N2b,. As described above, the lumen 9 in the external yoke 10 is moved in the X direction.

[Operation of Second Embodiment]
The force F acting between the coil and the permanent magnet is the same as that in Expression 3.
The maximum value Fmax of the force F is the same as that in Equation 4.
When the maximum value Fmax is differentiated with respect to time t, Expression 5 is obtained, and the phase velocity on the X axis is Expression 6. That is, also in the second embodiment, as in the first embodiment, the phase velocity is dx / dt = ω.

[Effect of the linear synchronous motor of the second embodiment]
The linear synchronous motor of the second embodiment also has the same effect as the linear synchronous motor of the first embodiment.
In the linear synchronous motor according to the second embodiment, the three-phase coil is formed in an annular shape, and the three-phase coil formed in an annular shape is fitted and fixed to the inner surface of the outer yoke. In addition, the torsional rigidity of the motor can be increased, and the thrust fluctuation can be reduced. As a result, superprecision control can be facilitated, and the motor constant and robustness can be improved.
In addition, since the second three-phase coil is arranged with a reverse polarity with respect to the first three-phase coil, the kinetic magnetic fluxes from the respective phase coils cancel each other, and there is almost no eddy current generated in the yoke. Iron loss can be significantly reduced.
Furthermore, since the coil is fixed to the external yoke, the heat dissipation is good, the influence of heat can be reduced, the cooling structure is easy to take, and the effect becomes remarkable, and consequently the thermal expansion of the yoke of the linear motor Can be suppressed.

Other Embodiments The linear synchronous motor of the present invention basically has a structure in which an electromagnet coil group is fitted to the inner wall of the outer yoke 10 and a permanent magnet group is fitted to the center yoke. Can be applied to various linear synchronous motors in which the positional relationship between each permanent magnet and each permanent magnet of the permanent magnet group and the current applied to the coil are synchronized.
Therefore, the linear synchronous motor of the present invention is not limited to the above-described embodiment, and can be applied to other various linear synchronous motors based on the above-described conditions.

1A to 1C are a cross-sectional view and a side view of a linear synchronous motor as a first embodiment of the present invention. FIG. 2 is a perspective view of a two-phase coil in the linear synchronous motor illustrated in FIGS. FIG. 3 is a diagram illustrating the positional relationship between the permanent magnet and the two-phase coil in the linear synchronous motor illustrated in FIGS. 4A to 4C are a cross-sectional view and a side view of a linear synchronous motor as a second embodiment of the present invention. FIG. 5 is a perspective view of a two-phase coil in the linear synchronous motor illustrated in FIGS. FIG. 6 is a diagram illustrating the positional relationship between the permanent magnet and the two-phase coil in the linear synchronous motor illustrated in FIGS.

Explanation of symbols

10 ... External yoke
10A ... Upper yoke, 10a ... Inner wall of upper yoke
10B: Lower yoke, 10b: Lower yoke inner wall
10C ... left side yoke, 10c ... left side yoke inner wall
10D ... Right side yoke, 10d ... Right side yoke inner wall
9 ... Lumen 3 ... Coil for electromagnet (3A1: 3A2, 3B1: 3B2)
4. Permanent magnet group (4S1a: 4S1b, 4N1a: 4N1b, 4S2a: 4S2b)
5 ... Center yoke S1a, N1a, S2a, N2a ... Permanent magnet (upper permanent magnet)
S1b, N1b, S2b, N2b ... Permanent magnet (lower permanent magnet)
6 ... Three-phase coil 6a ... First three-phase coil, 6b ... Second three-phase coil 6Ua ... U-phase coil, 6Ub ...- U-phase coil 6Wa ... W-phase coil, 6Wb ...- W-phase coil 6Va ... V-phase Coil, 6Vb ...- V phase coil

Claims (8)

An external yoke,
An electromagnet coil group that is inserted in and fixed to the inside of the outer yoke in an annular shape having a hollow cross section;
A center yoke arranged to be movable in the longitudinal direction of the outer yoke in the hollow of the coil group for the electromagnet,
A permanent magnet group disposed on opposite sides of the cross section of the center yoke in one direction so as to face the electromagnet coil group;
The permanent magnet group includes a plurality of permanent magnets alternately arranged with different magnetic poles in the longitudinal direction of the center yoke, and the same magnetic poles on both sides at the same position in the longitudinal direction of the center yoke,
The electromagnet coil group) includes a plurality of electromagnet coils disposed in a predetermined positional relationship with the plurality of permanent magnets in the longitudinal direction of the center yoke.
The predetermined positional relationship and the current applied to the plurality of electromagnet coils are set as synchronization conditions,
The center yoke and the plurality of permanent magnets move within the outer yoke in a synchronized state by thrust of electromagnetic force that interacts between the electromagnet coil group and the permanent magnet group.
Linear synchronous motor. A unit of a plurality of coils constituting the electromagnet coil group is a first coil to which a first-phase positive-phase alternating current is applied, which is disposed at a position angle of 3π / 4 (radian). A second coil to which an alternating current of the negative phase of the first phase is applied, and a positive current of the second phase having a π (radian) phase difference from the positive phase alternating current of the first phase. Is constituted by a third coil to which is applied, and a fourth coil to which an alternating current of the opposite phase of the second phase is applied,
One unit of a plurality of permanent magnets constituting the permanent magnet group is three permanent magnets arranged at a position angle of π (radian) on both sides of the center yoke in the longitudinal direction of the center yoke. It is configured,
The linear synchronous motor according to claim 1. The following currents Ia, Ib, Ic, Id are respectively applied to a plurality of coils constituting one unit of the electromagnet coil group.
Ia = Im × cos (ωt)
Ib = −Im × cos (ωt)
Ic = Im × sin (ωt)
Id = −Im × sin (ωt)
Here, Im is the maximum current amplitude.
The linear synchronous motor according to claim 2. A unit of a plurality of coils constituting the electromagnet coil group is a first coil to which a first-phase positive-phase alternating current is applied, which is disposed at a position angle of 3π / 4 (radian). A second coil to which an alternating current of the negative phase of the first phase is applied, and a positive alternating current of the second phase having a first phase difference from the positive alternating current of the first phase. A third coil to be applied; a fourth coil to which a second-phase alternating current is applied; and a third phase having a second phase difference from the positive-phase alternating current of the first phase. A fifth coil to which a positive phase alternating current is applied and a sixth coil to which a third phase reverse phase alternating current is applied,
One unit of the plurality of permanent magnets constituting the permanent magnet group is four permanent magnets arranged at a position angle of π (radian) on both sides of the center yoke in the longitudinal direction of the center yoke. It is configured,
The linear synchronous motor according to claim 1. The following currents IUa, IUb, IWa, IWb, IVa, IVb are respectively applied to a plurality of coils constituting one unit of the electromagnet coil group.
Here, Im is the maximum current amplitude.
IUa = Im × sin (ωt)
IUb = −Im × sin (ωt)
IWa = Im × sin (ωt + 8π / 3)
IWb = −Im × sin (ωt + 8π / 3)
IVa = Im × sin (ωt + 4π / 3)
IVb = −Im × sin (ωt + 4π / 3)
Here, Im is the maximum current amplitude.
The linear synchronous motor according to claim 4. The electromagnet coil group is fitted on the inner wall of the outer yoke,
The heat of the electromagnet coil group is dissipated through the external yoke,
The linear synchronous motor in any one of Claims 1-5. The outer yoke has a rectangular cross-sectional shape.
The linear synchronous motor in any one of Claims 1-6. The center yoke has a rectangular cross-sectional shape.
The linear synchronous motor in any one of Claims 1-7.

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