JP4563047B2 - Linear synchronous motor - Google Patents

Description

  The present invention relates to a linear synchronous motor, and more particularly, to a linear synchronous motor useful for positioning with nanometer unit ultraprecision.

As a linear synchronous motor that is frequently used in machine tools, semiconductor manufacturing apparatuses, and the like that require a large thrust, it is disclosed in, for example, Japanese Patent Laid-Open No. 2002-238240 (Patent Document 1). An outline of the linear synchronous motor will be described with reference to FIGS. 5 (A) to 5 (C) and FIG.
FIG. 5A is a cross-sectional view of a linear synchronous motor, FIG. 5B is a diagram showing the arrangement of coils illustrated in FIG. 5A, and FIG. 5C shows the phase and magnetic flux density. It is a figure which shows a relationship.

The linear synchronous motor illustrated in FIGS. 5A and 5B has the components listed below.
(1) A pair of yokes 1a and 1b which are spaced apart in parallel
(2) Among a pair of yokes 1a and 1b, a plurality of permanent magnets arranged along the longitudinal direction on the opposing surface of one yoke (hereinafter referred to as "upper yoke") 1a arranged at the upper position in the figure. (Hereinafter referred to as “upper permanent magnet”) S1a, N1a, S2a, N2a,.
(Hereinafter, the permanent magnet S1a is referred to as “the first permanent magnet having the S pole”,
The permanent magnet N1a is referred to as “first N pole upper permanent magnet”.
The permanent magnet S2a is referred to as "the second permanent magnet of the S pole",
The permanent magnet N2a is referred to as a “second N-pole upper permanent magnet”. )
(3) A plurality of permanent magnets (hereinafter referred to as “lower permanent magnets”) S1b, N1b disposed along the longitudinal direction on the opposing surface of a yoke (hereinafter referred to as “lower yoke”) 1b disposed at the lower position. , S2b, N2b, ...
(Hereinafter, the permanent magnet S1b is referred to as a “first permanent magnet having a lower S pole”.
The permanent magnet N1b is referred to as “first N pole lower permanent magnet”,
The permanent magnet S2b is referred to as a “second S pole lower permanent magnet”.
The permanent magnet N2b is referred to as a “second N pole lower permanent magnet”. )
(4) The movable part 2 is arranged 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 having 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 first and second three-phase coils 4a and 4b provided on both surfaces of the reinforcing plate 3, respectively.

  As shown in FIG. 6, the reinforcing plate 3 includes a rectangular plate-like body, and three positioning projections 31U, 31V, and 31W are provided at equal intervals on both surfaces thereof. A rectangular annular recess 32U, 32V, 32W is provided around each of the protrusions 31U, 31V, 31W.

  Each of the first and second three-phase coils 4a and 4b includes a U-phase coil 4U, a V-phase coil 4V and a W-phase coil 4W each formed in a rectangular ring shape. These U-phase coil 4U and V-phase coil As shown in FIG. 6, the 4V and W-phase coils 4W are fitted with the hollow portions 41U (see FIG. 5), 41V (see FIG. 5), 41W to the positioning projections 31U, 31V, 31W of the reinforcing plate 3. By doing so, it is integrated with the reinforcing plate 3.

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

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. The magnetic flux generated from the magnet N1b 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 lower permanent magnet S2b of the S pole and returns to the original lower permanent magnet N1b of the first N pole.
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. To do.
JP 2002-238240 A

  The linear synchronous motor having such a configuration encounters the following disadvantages.

  (1) First, since the movable portion 2 is designed to be flat and thin, the torsional rigidity is low, and the movable portion 2 is likely to generate minute vibrations.

  (2) Second, the speed and the current position of the movable part 2 fluctuate due to the slight vibration generated in the movable part 2, and such fluctuations are 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.

  (3) Thirdly, in the transverse magnetic flux type linear synchronous motor, as shown in FIG. 5C, the magnetic flux density is the central portion in the longitudinal direction of each permanent magnet (position where the phase is 90 degrees or 270 degrees). If the coil is positioned at the maximum part of the magnetic flux density and the maximum thrust is obtained, for example, if attention is paid to the V-phase coil 4V, the V-phase coil 4V deviates from the peak value of the magnetic flux density. Since it is located in the portion, the motor constant [N / √W] becomes small. N represents Newton and W represents power consumption.

  (4) Fourth, in order to improve the motor constant, the output must be increased. On the other hand, when the output increases, the heat generation increases, and as a result, the ambient temperature rises and errors due to thermal expansion tend to occur. Become.

  It is an object of the present invention to provide a linear synchronous motor that is highly rigid and has a small thrust fluctuation, that can easily perform ultra-precise control, and that can improve motor constants and disturbance resistance 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 the pair of yokes, A center yoke disposed in parallel with the pair of yokes; and annular first and second three-phase coils disposed in a loosely fitted state with the outer periphery so as to be movable along the outer periphery of the center yoke. ,
Each of the permanent magnets has a permanent magnet of the same polarity arranged at the opposing position of the pair of yokes, and permanent magnets of different polarities are alternately arranged in the longitudinal direction of the pair of yokes.
The first three-phase coil and the second three-phase coil are arranged apart from each other by a width of one permanent magnet along the longitudinal direction of the center yoke, and the first three-phase coil and wherein each of the longitudinal dimension of the second three-phase coil is the same as the longitudinal dimension of the two component prior KiHisashi permanent magnet,
A linear synchronous motor is provided.

  Preferably, the first three-phase coil in the linear synchronous motor of the present invention is configured by arranging the U-phase coil, the V-phase coil, and the W-phase coil in the phase order along the longitudinal direction of the center yoke. The three three-phase coils are configured by arranging the -U phase coil, the -V phase coil, and the -W phase coil in the phase order along the longitudinal direction of the center yoke, and the W phase of the first three phase coil The -U phase coil of the second three-phase coil is arranged facing the coil.

  According to the linear synchronous motor of the present invention, since the annular three-phase coil is mounted on the outer periphery of the center yoke, it is possible to increase the rigidity of the coil, and thus to reduce the thrust fluctuation, Ultra-precise control can be easily performed, and motor constants and disturbance resistance can be improved.

A preferred embodiment of the linear synchronous motor of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic configuration diagram of a linear synchronous motor as a first embodiment of the present invention, and FIG. 2 is a perspective view of first and second three-phase coils in the linear synchronous motor illustrated in FIG. 1 and FIG. 2, the same reference numerals are given to the same parts as those in FIG. 5 and FIG.
FIG. 3 is a diagram illustrating the magnetic flux density when the maximum thrust is generated in the coil V in the linear synchronous motor illustrated in FIGS. 1 and 2, for example.
FIG. 4 is a characteristic diagram of the linear synchronous motor illustrated in FIG.

The linear synchronous motor illustrated in FIG. 1 includes the following components.
(1) A pair of plate-shaped yokes (upper and lower yokes) 1a and 1b arranged in parallel and spaced apart from each other
(2) A plurality of permanent magnets (upper permanent magnets) S1a, N1a, S2a, N2a,... Arranged along the longitudinal direction on the opposing surface of the upper yoke 1a.
(3) A plurality of permanent magnets (lower permanent magnets) S1b, N1b, S2b, N2b,... Arranged along the longitudinal direction on the opposing surface of the lower yoke 1b.
(4) A center yoke 5 disposed in a central portion between the upper and lower yokes 1a and 1b in parallel with the upper and lower yokes 1a and 1b.
(5) Annular first and second three-phase coils 6a and 6b which are mounted on the outer periphery of the center yoke 5 in a loosely fitted state and are arranged so as to be movable in the X direction.

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 upper permanent magnets S1a and N1a having poles and N poles and the lower permanent magnets S1b and N1b having first S poles and N poles are arranged to face each other.
The upper permanent magnets S1a, N1a, S2a, N2a,... Are alternately composed of permanent magnets having different polarities along the longitudinal direction (S pole, N pole,... S pole), like the linear synchronous motor illustrated in FIG. It is arranged to be located in.
Similarly to the linear synchronous motor illustrated in FIG. 5, the lower permanent magnets S1b, N1b, S2b, N2b,... Alternate with permanent magnets having different polarities along the longitudinal direction (S pole, N pole,... S pole). It is arranged to be located in.

  The center yoke 5 has a role of guiding the movement of the first and second three-phase coils 6a and 6b in the X direction, and the outer shape of the center yoke 5 is first and second three-phase coils 6a and 6b described later. Is substantially the same shape as the hollow portion 62, for example, a substantially rectangular shape in a cross-sectional view.

As shown in FIG. 2, the first three-phase coil 6a includes, for example, a U-phase coil 6U, a V-phase coil 6V, and a W-phase coil 6W that are formed in a rectangular ring shape.
The U-phase coil 6U, the V-phase coil 6V, and the W-phase coil 6W are formed by winding a conductive wire such as an enamel wire in a rectangular ring shape with the same specifications, and an adhesive such as an epoxy resin between the conductive wires. It is fixed in a state in which a rectangular annular shape is maintained.
The U-phase coil 6U, the V-phase coil 6V, and the W-phase coil 6W are arranged so that the axial centers of the hollow portions 62 coincide with each other and along the X direction, the U-phase coil 6U, the V-phase coil 6V, and the W-phase coil 6W. The nonmagnetic insulating members 61a and 61b are inserted between the coils of each phase.

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.
These -U-phase coil 6U, -V-phase coil 6V and -W-phase coil 6W are arranged such that the axial centers of the hollow portions 62 coincide with each other, and the -U-phase coil 6U and -V-phase coil 6V are aligned along the X direction. The non-magnetic insulating members 61a and 61b are interposed between the coils of each phase.

A first three-phase coil 6a that includes the U-phase coil 6U, V-phase coil 6V, and W-phase coil 6W, and a set of -U-phase coil 6U, -V-phase coil 6V, and -W-phase coil 6W. The dimensions of the second three-phase coil 6b in the longitudinal direction (X direction) are two permanent magnets, for example, a first N-pole upper permanent magnet N1a and a second S-pole upper permanent magnet S2a. It is set to be the same as the longitudinal dimension of (or the first N-pole lower permanent magnet N1b and the second S-pole lower permanent magnet S2b).
That is, with respect to two permanent magnets, the first three-phase coil 6a including the U-phase coil 6U, the V-phase coil 6V, and the W-phase coil 6W, and the -U-phase coil 6U, the -V-phase coil 6V, and A second three-phase coil 6b including the W-phase coil 6W as a set is configured as an operation unit.

  Here, -U phase coil 6U, -V phase coil 6V, and -W phase coil 6W are U phase coil 6U, V phase coil 6V, and W phase coil 6W, respectively. 6V and W-phase coil 6W are arranged.

The first and second three-phase coils 6 a and 6 b having such a configuration are arranged on the outer periphery of the center yoke 5 and spaced apart along the longitudinal direction of the center yoke 5.
In addition, the W-phase coil 6W of the first three-phase coil 6a is arranged to face the -U-phase coil-6U of the second three-phase coil 6b.
Here, the distance between the first and second three-phase coils 6a and 6b is the same as the length in the longitudinal direction of one permanent magnet.

In the linear synchronous motor having such a configuration, 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. For example, the upper part of the first N pole The magnetic flux generated from the permanent magnet N1a passes through the first three-phase coil 6a, passes through the center yoke 5 and passes through the adjacent second S pole upper permanent magnet S2a, and then passes through the upper permanent magnet of the original first N pole. Return to magnet N1a.
The magnetic flux generated from the first N-pole lower permanent magnet N1b passes through the first three-phase coil 6a, passes through the center yoke 5 and passes through the adjacent second S-pole lower permanent magnet S2b. The first N pole lower permanent magnet N1b is returned to.
Similarly, for example, the magnetic flux generated from the third N-pole upper permanent magnet N3a passes through the second three-phase coil 6b and passes through the center yoke 5 to the adjacent third S-pole upper permanent magnet S3a. And return to the original third N-pole upper permanent magnet N3a.
The magnetic flux generated from the third N-pole lower permanent magnet N3b passes through the second three-phase coil 6b, passes through the center yoke 5 and passes through the adjacent third S-pole lower permanent magnet S3b, Return to the third N pole lower permanent magnet N3b.

A first three-phase coil 6a including a U-phase coil 6U, a V-phase coil 6V, and a W-phase coil 6W arranged in such a magnetic field, and a -U-phase coil 6U, a -V-phase coil 6V, and- When a three-phase alternating current is passed through each of the second three-phase coils 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 second three-phase coils 6a and 6b move in the X direction.
FIG. 3 is a diagram illustrating the magnetic flux density when the maximum thrust is generated in the coil V in the linear synchronous motor illustrated in FIGS. 1 and 2, for example.

  As described above, according to the linear synchronous motor of the embodiment of the present invention, the first and second three-phase coils 6a and 6b are formed in an annular shape, and the three-phase coil formed in an annular shape is a center yoke. Since the three-phase coil has higher torsional rigidity than the linear synchronous motor illustrated in FIG. 4, the thrust fluctuation can be reduced.

  Furthermore, ultraprecision control is facilitated, and the motor constant and disturbance resistance performance of the linear synchronous motor can be improved.

  Furthermore, since each phase coil of the linear synchronous motor of this embodiment 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. . As a result, the necessary motor current is reduced, and as a result, Joule heat can be reduced.

  In the linear synchronous motor of the present embodiment, since the second three-phase coil 6b is arranged with the opposite polarity with respect to the first three-phase coil 6a, the kinetic magnetic flux from each phase coil is mutually The eddy current generated in the yoke is almost eliminated and the iron loss can be remarkably reduced.

  In the linear synchronous motor according to the embodiment of the present invention, the second three-phase coil 6b is arranged so as to have a reverse polarity with respect to the first three-phase coil 6a, so that the torsional rigidity and the motor constant are improved. In addition, thrust non-linearization can be prevented. That is, in a linear synchronous motor having only one three-phase coil (for example, the first three-phase coil 6a), the yoke, the center yoke, and the like are magnetically saturated due to the fluctuation of the magnetic field due to the AT (ampere turn) of the coil. In order to weaken the magnetic field of the magnet, as shown by the characteristic shown by the curve b in FIG. 4, the thrust shows a non-linear characteristic with respect to a three-phase alternating current. In the linear synchronous motor according to the embodiment of the present invention arranged so that the second three-phase coil 6b has a reverse polarity with respect to the phase coil 6a, the magnetic flux from each phase coil is caused by the magnetic flux of the reverse-polarity coil. Since they cancel each other, the characteristics shown in the curve a of FIG.

As is clear from the above, in the linear synchronous motor according to the embodiment of the present invention, it is possible to further increase the thrust, further reduce the heat generation, and thus control in nanometer units. It can be done easily.
The characteristic of the linear synchronous motor is also a linear characteristic indicated by a curve a in FIG. 4, and the control can be performed more easily.
Furthermore, since the magnetic flux of the coil is canceled out, iron loss can be greatly reduced, and adverse effects due to motor efficiency and heat generation can be avoided.

Modified Embodiment In the linear synchronous motor of the above-described embodiment , the case where the first and second three-phase coils 6a and 6b are mounted loosely on the outer periphery of the center yoke is described. The first and second three-phase coils 6a and 6b may be mounted and fixed and moved together with the center yoke.
In this case, the cooling efficiency can be improved by providing a passage along the longitudinal direction in the center yoke and flowing a cooling medium in the passage.

  Further, a cooling pipe may be loosely fitted to the head portion of the coil. In this case, cooling in a vacuum can be easily performed.

According to the linear synchronous motor of the present invention, the first and second three-phase coils 6a and 6b are formed in an annular shape, and the three-phase coil formed in an annular shape is mounted on the outer periphery of the center yoke. Compared to the linear synchronous motor illustrated in FIG. 5, the torsional rigidity of the three-phase coil is higher, and hence the thrust fluctuation can be reduced. In addition, ultraprecision control can be easily performed and the disturbance resistance performance is also improved. be able to.
Furthermore, each phase coil in the linear synchronous motor of the present embodiment can obtain a maximum thrust at the maximum magnetic flux density portion of the permanent magnet and improve the thrust constant, so that the motor constant can be reduced and necessary. As a result, the motor current is reduced, and as a result, Joule heat can be reduced.

FIG. 1 is a schematic configuration diagram of a linear synchronous motor according to an embodiment of the present invention. FIG. 2 is a perspective view of first and second three-phase coils in the linear synchronous motor illustrated in FIG. FIG. 3 is a diagram illustrating the magnetic flux density when the maximum thrust is generated in the coil V in the linear synchronous motor illustrated in FIGS. 1 and 2. FIG. 4 is a diagram illustrating the characteristics of the linear synchronous motor illustrated in FIGS. 1 and 2 and the characteristics of the linear synchronous motor illustrated in FIG. 5A and 5B are schematic configuration diagrams of a conventional linear synchronous motor, and FIG. 5C is a relationship between the phase of the linear synchronous motor illustrated in FIGS. 5A and 5B and the magnetic flux density. FIG. FIG. 6 is a schematic configuration diagram of a movable portion in the linear synchronous motor illustrated in FIG.

Explanation of symbols

1a ... Yoke (upper yoke), 1b ... Yoke (lower yoke)
S1a, N1a, S2a, N2a ... Permanent magnet (upper permanent magnet)
S1b, N1b, S2b, N2b ... Permanent magnet (lower permanent magnet)
5 ... Center yoke 6a ... First three-phase coil 6U ... U-phase coil 6V ... V-phase coil 6W ... W-phase coil 6b ... Second three-phase coil 6U ...- U-phase coil 6V ...- V-phase coil 6W ...- W phase coil

Claims (2)

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;
A center yoke disposed in parallel with the pair of yokes between the pair of yokes;
An annular first and second three-phase coil disposed in a loose fit with the outer periphery so as to be movable along the outer periphery of the center yoke;
Each of the permanent magnets has a permanent magnet of the same polarity arranged at the opposing position of the pair of yokes, and permanent magnets of different polarities are alternately arranged in the longitudinal direction of the pair of yokes.
The first three-phase coil and the second three-phase coil are arranged apart from each other by a width of one permanent magnet along the longitudinal direction of the center yoke, and the first three-phase coil and wherein each of the longitudinal dimension of the second three-phase coil is the same as the longitudinal dimension of the two component prior KiHisashi permanent magnet,
Linear synchronous motor. The first three-phase coil is composed of a U-phase coil, a V-phase coil, and a W-phase coil arranged in the phase order along the longitudinal direction of the center yoke.
The second three-phase coil is configured by being arranged in the phase order of a -U phase coil, a -V phase coil, and a -W phase coil along the longitudinal direction of the center yoke,
The -U phase coil of the second three-phase coil is arranged to face the W-phase coil of the first three-phase coil,
The linear synchronous motor according to claim 1.

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