JP2005237078A - Linear synchronous motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear synchronous motor which can improve its cooling efficiency and can improve its motor constant and robustness. <P>SOLUTION: This linear motor has such construction that it elevates its cooling effect. That is, this linear motor is equipped with a pair of upper and lower yokes 10a and 10b, and a plurality of permanent magnets are arranged on the opposite faces of the upper and lower yokes 10a and 10b. A center yoke 50 is arranged at the central part between the upper and lower yokes 10a and 10b, and first and second circular three-phase coils 6a and 6b are arranged around this center yoke 50. Upper permanent magnets S1a, N1a,... and lower permanent magnets S1b, N1b,... arranged at the opposite faces of the upper and lower yokes 1a and 1b are arranged so that the permanent magnets of the same polarity may oppose each other on the same vertical line. The center yoke 50 is equipped with a tubular body 500a as a cooling passage 500. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a linear synchronous motor, and more particularly to a linear synchronous motor useful for fine vibration control of a vibration isolator / vibration control device and positioning with nanometer unit ultra-precision.

  As a linear synchronous motor that is frequently used in machine tools, semiconductor manufacturing apparatuses, and the like that require a large thrust, for example, a technique disclosed in Japanese Patent Laid-Open No. 2002-238240 (Patent Document 1) is known. The schematic configuration is illustrated in FIGS.

In FIG. 3A, the linear synchronous motor has the following.
(A) A pair of yokes 1a and 1b arranged to be spaced apart in parallel
(B) Of the pair of yokes 1a and 1b, disposed along the longitudinal direction on the opposing surface of one yoke 1a (hereinafter referred to as “upper yoke 1a”) disposed at the upper position in FIG. A plurality of permanent magnets S1a, N1a, S2a, N2a,... (Hereinafter referred to as “upper permanent magnets S1a, N1a, S2a, N2a,... The permanent magnet N1a is referred to as "first N pole upper permanent magnet", the permanent magnet S2a is referred to as "second S pole upper permanent magnet", and the permanent magnet N2a is referred to as "second N pole upper permanent magnet". Upper permanent magnet 2a "),
(C) A plurality of permanent magnets S1b, N1b, S2b, N2b,... (Hereinafter referred to as the longitudinal direction) on the opposing surface of the yoke 1b (hereinafter referred to as “lower yoke 1b”) disposed at the lower position. “Lower permanent magnets S1b, N1b, S2b, N2b,...”, Hereinafter, the permanent magnet S1b is referred to as “first S pole lower permanent magnet 1b”, and the permanent magnet N1b is referred to as “lower first N pole. Permanent magnet 1b ", permanent magnet S2b is called" second S pole lower permanent magnet S2b ", and permanent magnet N2b is called" second N pole lower permanent magnet N2b ".
(D) A movable part 2 disposed in a central portion between the upper and lower yokes 1a and 1b so as to be movable in parallel with the upper and lower yokes 1a and 1b (hereinafter referred to as “X direction”).

The upper permanent magnets S1a, N1a, S2a, N2a,... And the lower permanent magnets S1b, N1b, S2b, N2b,... Are arranged so that the permanent magnets of different polarities face each other on the same vertical line. The N-pole upper permanent magnet N1a and the first S-pole lower permanent magnet S1b are arranged to face each other.
Further, the upper permanent magnets S1a, N1a, S2a, N2a,... Are adjacent to, for example, the first N-pole upper permanent magnet N1a so that permanent magnets having different polarities are alternately positioned along the longitudinal direction. The first S-pole upper permanent magnet S1a is arranged so that the second N-pole upper permanent magnet N2a is located adjacent to the first S-pole upper permanent magnet S1a.
Similarly, the lower permanent magnets S1b, N1b, S2b, N2b,... Are adjacent to the lower permanent magnet S1b of the first S pole, for example, so that permanent magnets of different polarities are alternately positioned along the longitudinal direction. The first N-pole lower permanent magnet N1b is disposed adjacent to the first N-pole lower permanent magnet N1b so as to be positioned at the second S-pole lower permanent magnet S2b.

  The movable part 2 includes a nonmagnetic reinforcing plate 3 and flat three-phase coils 4 a and 4 b provided on both surfaces of the reinforcing plate 3, respectively.

  As shown in FIG. 4, the reinforcing plate 3 has a rectangular plate-like body, and three positioning projections 31U, 31V, and 31W are provided at equal intervals on both surfaces. A rectangular annular recess 32U, 32V, 32W is provided around each of the protrusions 31U, 31V, 31W.

  As illustrated in FIG. 3B, the two three-phase coils 4a and 4b illustrated in FIG. 3A are respectively formed into a U-phase coil 4U, a V-phase coil 4V, and a W-phase coil formed in a rectangular ring shape. 4W, these U-phase coil 4U, V-phase coil 4V, and W-phase coil 4W have hollow portions 41U (see FIG. 3B), 41V (see FIG. 3B) as shown in FIG. )), And 41W is integrated with the reinforcing plate 3 by fitting it to the positioning projections 31U, 31V, 31W of the reinforcing plate 3.

  The dimension in the longitudinal direction (X direction) of the three-phase coils 4a and 4b is the dimension in the longitudinal direction (X direction) of two permanent magnets, for example, the upper permanent magnet S1a of the first S pole and the second N The upper permanent magnet N2a having a pole (or the lower permanent magnet N1b having the first N pole and the lower permanent magnet S2b having the second S pole) is configured to be equal to the dimension in the longitudinal direction (X direction).

The linear synchronous motor having such a configuration employs a so-called transverse magnetic flux type excitation structure in which permanent magnets having different polarities are arranged on the same vertical line. For example, the magnetic flux generated from the magnet passes through the V-phase coil 4V, passes through the first S-pole upper permanent magnet S1a, and is adjacent to the second N-pole upper permanent magnet N2a, the V-phase coil 4V, and the second It passes through the S-pole lower permanent magnet S2b and returns to the original first N-pole lower permanent magnet N1b.
Therefore, when a three-phase alternating current is passed through the U-phase coil 4U, V-phase coil 4V and W-phase coil 4W arranged in such a magnetic field, thrust based on the Fleming left-hand rule is generated in the three-phase coils 4a and 4b. Will do.
JP 2002-238240 A

However, the linear synchronous motor having such a configuration encounters the following disadvantages.
The first disadvantage is that since the movable part 2 is flat and designed to be thin, the torsional rigidity is low and the movable part 2 is likely to generate micro vibrations.
The second disadvantage is that the speed and the current position of the movable part 2 fluctuate due to the slight vibration generated in the movable part 2, and the fluctuation is fed back through the position sensor to further amplify the vibration. As a result, the control gain becomes low, and it becomes difficult to control in nanometer units.
A third disadvantage is that a nonmagnetic bobbin is interposed in the magnetic field of the magnet, the magnetic flux density of the magnet is lowered, and it is difficult to obtain a large thrust. Furthermore, if an attempt is made to increase the output of the linear synchronous motor, heat generation increases, and as a result, the ambient temperature rises, and errors due to thermal expansion tend to occur.

  The object of the present invention is to overcome the above-mentioned disadvantages. It is highly rigid, has little thrust fluctuation, generates little heat, and can easily perform ultra-precise control, and also has a motor constant and resistance. An object of the present invention is to provide a linear synchronous motor capable of improving disturbance performance.

  According to the present invention, a pair of yokes spaced apart in parallel, a plurality of permanent magnets respectively disposed along the longitudinal direction on the opposing surface of each yoke, and parallel to the yoke between the pair of yokes A center yoke disposed on the outer periphery of the center yoke and an annular three-phase coil mounted on the outer periphery of the center yoke. Each permanent magnet has a permanent magnet of the same polarity at the opposite position of the yoke. A linear synchronous motor is provided in which permanent magnets of different polarities are alternately arranged in the direction, and the center yoke is provided with a cooling passage along the longitudinal direction of the center yoke.

Preferably, the cooling passage in the linear synchronous motor of the present invention is formed of a rectangular cylindrical body.
Preferably, the cylindrical body in the linear synchronous motor of the present invention is configured by being divided into two along the longitudinal direction of the center yoke.
More preferably, the cylindrical body in the linear synchronous motor of the present invention is divided along the longitudinal direction of the center yoke on a plane parallel to the vertical plane.
More preferably, a pipe is inserted along the longitudinal direction of the center yoke into the cylindrical body of the linear synchronous motor of the present invention.
Preferably, the three-phase coils are arranged in a u phase, a -u phase, a W phase, a -W phase, a V phase, and a -V phase.

According to the linear synchronous motor of the present invention, since the cooling passage is provided in the center yoke, the cooling medium (coolant) can flow in the cooling passage, and therefore, cooling is performed more than the conventional linear synchronous motor. Efficiency can be improved.
Furthermore, since the annular three-phase coil is mounted on the outer periphery of the center yoke, the rigidity of the coil can be increased, and consequently the fluctuation of thrust can be reduced.
Furthermore, ultra-precise control can be easily performed, and the motor constant and disturbance resistance can be improved.
Further, when the three-phase coil is arranged in the u-phase, -u-phase, W-phase, -W-phase, V-phase, and -V-phase, the rising characteristic of thrust can be made steep.

A preferred embodiment of the linear synchronous motor of the present invention will be described with reference to FIGS.
1A to 1C are schematic configuration diagrams of a linear synchronous motor according to one embodiment of the present invention, and FIG. 2 is a perspective view of a three-phase coil in the linear synchronous motor according to the present embodiment. Yes.
In FIG. 1 to FIG. 2, the same reference numerals are given to the portions common to FIG. 3 and FIG.

In FIG. 1A, the linear synchronous motor according to the embodiment of the present invention is provided with those listed below.
(A) Cylindrical outer yoke 10
(B) A plurality of first group of permanent magnets S1a, N1a, S2a, N2a,... (Upper part) arranged along the longitudinal direction on the upper inner surface 10a of the outer yoke 10 (hereinafter referred to as “upper yoke 10a”). Permanent magnet group S1a, N1a, S2a, N2a, ...)
(C) A plurality of second group of permanent magnets S1b, N1b, S2b, N2b,... (Hereinafter, referred to as the lower inner surface 10b of the outer yoke 10 (hereinafter referred to as “lower yoke 10b”). "Lower permanent magnet group S1b, N1b, S2b, N2b, ...)
(D) A center yoke 50 disposed in the outer yoke 10 so as to be movable along the axis of the outer yoke 10.
(E) Annular first and second three-phase coils 6a and 6b mounted on the outer periphery of the center yoke 50.

Side yokes 100a and 100b that close both ends are provided at both ends of the cylindrical outer yoke 10, and through holes 200a and 200b that pass through the center yoke 50 are provided in these side yokes 100a and 100b. Yes.
The diameters of the through holes 200 a and 200 b are set to be slightly larger than the outer diameter of the center yoke 50.

The upper permanent magnets S1a, N1a, S2a, N2a,... And the lower permanent magnets S1b, N1b, S2b, N2b,... Are arranged so that, for example, the first S The pole / N pole upper permanent magnets S1a / N1a and the first S pole / N pole lower permanent magnets S1b / N1b are arranged to face each other.
Further, the upper permanent magnets S1a, N1a, S2a, N2a,... Are arranged so that permanent magnets having different polarities are alternately (S pole, N pole,... S pole) along the longitudinal direction.
Similarly, the lower permanent magnets S1b, N1b, S2b, N2b,... Are also arranged so that permanent magnets having different polarities are alternately (S pole, N pole,... S pole) along the longitudinal direction. .

The center yoke 50 is configured to move in the X direction together with the first and second three-phase coils 6a and 6b mounted on the outer periphery of the center yoke 50.
The center yoke 50 is provided with a cooling passage 500 along the longitudinal direction of the center yoke 50, and the cooling medium 60 is circulated in the cooling passage 500.

FIG. 1B shows an example of the center yoke 50 of the linear synchronous motor of the present embodiment.
The center yoke 50 includes a cylindrical body 500a as a cooling passage 500, and the cylindrical body 500a is formed in a substantially rectangular shape in a cross-sectional view.
In the present embodiment, the cylindrical body 500a as the cooling passage 500 is configured by being divided by a plane parallel to a vertical plane (a plane orthogonal to the X direction). Here, the reason why the cylindrical body 500a is divided by a plane parallel to the vertical plane is to prevent deformation of the center yoke 50 (cylindrical body 500a as the cooling passage 500) from the magnetic attraction force of the upper and lower permanent magnets. is there.
In addition, the code | symbol 50a, 50b in the figure has shown the half part (half body or half cylinder body) of the respectively divided | segmented cylindrical body.

FIG. 1C shows another embodiment of a cylindrical body 500a as the cooling passage 500. As shown in FIG. In the embodiment illustrated in FIG. 1 (C), a small-sized pipe 500b similar to the cylindrical body 500a is inserted along the axial direction into the cylindrical body 500a.
In the present embodiment, the cooling medium 60 can be circulated using the cylindrical body 500a as the forward path and the pipe 500b as the return path.

As shown in FIG. 2, the first three-phase coil 6a includes, for example, a U-phase coil 6Ua, a V-phase coil 6Va, and a W-phase coil 6Wa formed in a rectangular ring shape. These U-phase coil 6Ua, V-phase coil 6Va and W-phase coil 6Wa have the same specifications, for example, are formed by winding a conducting wire such as an enamel wire in a rectangular ring shape, and an epoxy resin or the like between the conducting wires. By infiltrating the adhesive, it is fixed in a state in which a rectangular annular shape is maintained.
Similarly, as shown in FIG. 2, the second three-phase coil 6b includes, for example, a -U phase coil 6U, a -V phase coil 6V, and a -W phase coil 6W formed in a rectangular ring shape. The -U phase coil 6U, -V phase coil 6V, and -W phase coil 6W are formed with the same specifications as the first three-phase coil 6a, and maintain a rectangular annular shape with an adhesive. It is fixed with.

The U-phase coil 6Ua, -U-phase coil 6Ub, V-phase coil 6Va, -V-phase coil 6Vb, W-phase coil 6Wa, and -W-phase coil 6Wb constituting the first and second three-phase coils 6a and 6b are as follows: It is integrated as follows.
That is, the -U-phase coil 6Ub of the second three-phase coil 6b is arranged adjacent to the U-phase coil 6Ua of the first three-phase coil 6a, and the second-phase coil 6Va of the first three-phase coil 6a is second. The -V phase coil 6Vb of the three-phase coil 6b is arranged adjacent to the W-phase coil 6Wb of the first three-phase coil 6a, and the -W-phase coil 6Wb of the second three-phase coil 6b is arranged adjacent to the W-phase coil 6Wb. The coils of the respective phases are arranged in a laminated state in the order of the U phase, the V phase, and the W phase along the X direction so that the axes of the hollow portions 62 coincide with each other.
In addition, nonmagnetic insulating members 61a, 61b, 61c, 61d, and 61e are interposed between the coils of each phase.

The linear synchronous motor having the above-described configuration employs a so-called axial magnetic flux type excitation structure in which permanent magnets having the same polarity are arranged on the same vertical line. The magnetic flux generated from the magnet N1a passes through the three-phase coil 6, passes through the center yoke 50, passes through the adjacent second S pole upper permanent magnet S2a, and returns to the original first N pole upper permanent magnet N1a. .
Further, the magnetic flux generated from the first N-pole lower permanent magnet N1b passes through the three-phase coil 6, passes through the center yoke 50, passes through the adjacent second S-pole lower permanent magnet S2b, and returns to the original first. Return to the N-pole lower permanent magnet N1b.
Therefore, the first three-phase coil 6a and the -U-phase coil 6U, the -V-phase coil 6V, the U-phase coil 6U, the V-phase coil 6V, and the W-phase coil 6W arranged in such a magnetic field -When a three-phase alternating current is passed through the second three-phase coil 6b including the W-phase coil 6W as a set, a thrust based on the "Fleming left-hand rule" is generated in each phase coil. The center yoke 50 moves in the X direction and effectively operates as a linear synchronous motor.

In the above-described embodiment, the first and second three-phase coils are mounted on the outer periphery of the center yoke. However, even if only the first three-phase coil or the second three-phase coil is mounted. Good.
The phase order of the first and second three-phase coils may be the phase order of the U-phase coil, the W-phase coil, and the V-phase coil.
Further, the three-phase coil is not limited to the one fixed to the outer periphery of the center yoke, and the three-phase coil may be loosely fitted to the outer periphery of the center yoke so as to be movable in the longitudinal direction.

As is clear from the above description, according to the linear synchronous motor of the present invention, since the cooling passage is provided in the center yoke, a cooling medium (coolant or coolant) is allowed to flow in the cooling passage. Can be cooled forcibly. As a result, the cooling efficiency can be improved as compared with the conventional linear synchronous motor.
As the coolant, various materials such as liquid and gas can be used.

Further, since the annular three-phase coil is mounted on the outer periphery of the center yoke, the rigidity of the coil can be increased, and consequently the fluctuation of thrust can be reduced.
Furthermore, ultra-precise control can be easily performed, and motor constants and disturbance resistance (robustness) can be improved.

  Furthermore, each phase coil in the linear synchronous motor can obtain the maximum thrust at the maximum magnetic flux density portion of the permanent magnet, that is, the degree of effective utilization of the magnetic field by the permanent magnet is increased, and the thrust constant is improved. The required motor current is reduced, and as a result, Joule heat can be reduced.

Further, in the linear synchronous motor, when the second three-phase coil is arranged with the reverse polarity with respect to the first three-phase coil, the kinetic currents from the respective phase coils cancel each other, and the eddy current generated in the yoke Was almost eliminated, and iron loss could be remarkably reduced.
Furthermore, when the three-phase coils are arranged in the u-phase, -u-phase, W-phase, -W-phase, V-phase, and -V-phase, the rising characteristics of the transient thrust can be sharpened.

FIG. 1A is a schematic explanatory diagram of a linear synchronous motor as an embodiment of the present invention, and FIG. 1B is a linear synchronization as an embodiment of the present invention illustrated in FIG. FIG. 1C is a cross-sectional view of the center yoke in the motor, and FIG. 1C is a cross-sectional view of the center yoke in the linear synchronous motor as one embodiment of the present invention illustrated in FIG. FIG. 2 is a perspective view of a three-phase coil in the linear synchronous motor according to the embodiment of the present invention illustrated in FIGS. 3A to 3C are schematic explanatory views of a conventional linear synchronous motor. FIG. 4 is a schematic explanatory view of a movable portion in the conventional linear synchronous motor illustrated in FIGS.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Outer yoke 10a ... Upper inner surface (upper yoke), 10b ... Lower inner surface (lower yoke)
S1a, N1a, S2a, N2a ... Permanent magnet (upper permanent magnet)
S1b, N1b, S2b, N2b ... Permanent magnet (lower permanent magnet)
5 ... Center yoke 6 ... Three-phase coil 6a ... First three-phase coil, 6b ... Second three-phase coil 6Ua ... U-phase coil, 6Wa ... W-phase coil, 6Va ... V-phase coil 6Ub ...- U-phase coil, 6Wb ...- W phase coil, 6Vb ...- V phase coil 50 ... Center yoke 500 ... Cooling passage, 500a ... Cylindrical body, 500b ... Pipe 50a, 50b ... Divided cylindrical body 60 ... Cooling medium (cooling material, cooling Agent)

Claims (6)

A pair of yokes spaced apart in parallel;
A permanent magnet group consisting of a plurality of permanent magnets respectively disposed along the longitudinal direction on the opposing surface of each yoke;
A center yoke disposed parallel to the yoke between the pair of yokes;
An annular three-phase coil mounted on the outer periphery of the center yoke,
In each of the permanent magnet groups, permanent magnets having the same polarity are arranged at positions facing the yoke, and permanent magnets having different polarities are alternately arranged in the longitudinal direction of the yoke,
The center yoke includes a cooling passage through which a coolant passes along a longitudinal direction of the center yoke.
Linear synchronous motor. The cooling passage is composed of a rectangular cylindrical body,
The linear synchronous motor according to claim 1. The cylindrical body is configured by being divided into two along the longitudinal direction of the center yoke.
The linear synchronous motor according to claim 2. The cylindrical body is divided along the longitudinal direction of the center yoke in a plane parallel to the vertical plane.
The linear synchronous motor according to claim 1. Inside the cylindrical body, a pipe through which a coolant passes is inserted along the longitudinal direction of the center yoke.
The linear synchronous motor according to claim 4. The three-phase coils are arranged in u phase, -u phase, W phase, -W phase, V phase, -V phase,
The linear synchronous motor in any one of Claims 1-5.

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