JPWO2015177883A1 - Linear motor and equipment equipped with linear motor - Google Patents

Abstract

A linear motor capable of efficiently controlling the attitude of a mover and applying a magnetic levitation force and a device equipped with the linear motor are provided. An armature having two magnetic pole teeth facing each other through a gap, a winding wound around the magnetic pole teeth, and a mover in which a plurality of permanent magnets having polarity in the vertical direction are arranged in the front-rear direction; The mover has a long pole portion having a predetermined length in the front-rear direction as an array of a plurality of permanent magnets, and a length in the front-rear direction shorter than the length in the front-rear direction of the long pole portion. And the mover has a long pole portion in a flat plate-shaped portion having a width in the left-right direction, and the long pole portion moves relative to the armature in the front-rear direction to form a gap. It is possible to reciprocate.

Description

  The present invention relates to a linear motor and a device equipped with the linear motor.

  As background art regarding a linear motor, for example, Patent Literatures 1 and 2 are cited. Patent Document 1 describes a magnetic support device that magnetically supports a support. Patent Document 2 describes a magnetic bearing 4a in which a stator and a coil are combined to magnetically levitate a piston shaft 2a (0008).

JP 2005-36839 A Japanese Patent Laid-Open No. 7-4763

  A displacement sensor 4 is installed on the outer periphery of the supported body 1 of Patent Document 1, and is configured to measure the clearance between the supported body 1 and the electromagnet 3. In Patent Document 1, although the displacement of the supported body between the electromagnets can be controlled, it is difficult to control the rotation of the supported body.

  Moreover, in patent document 2, although the shaft of a piston is levitated by the magnetic bearing, the force which rotates a piston may be applied with the reaction force accompanying a compression / expansion process. In the magnetic bearing of Patent Document 2, it is difficult to control the rotation of the shaft. For this reason, there is a possibility that a loss due to friction with the compression chamber peripheral wall of the piston may occur, or the sealing performance of the compression chamber may be deteriorated. Further, in Patent Document 2, in order to obtain a stable magnetic levitation force, it is necessary to uniformly magnetize the outer periphery of the shaft. For this, for example, a ring-shaped permanent magnet may be used. However, in order to realize the permanent magnet in a ring shape, a certain diameter is required and it is difficult to reduce the size.

  Accordingly, an object of the present invention is to provide a linear motor that can efficiently control the attitude of the mover and impart magnetic levitation force, and a device equipped with the linear motor.

In order to solve the above problems, for example, the configuration described in the claims is adopted.
The present application includes a plurality of means for solving the above-described problems. To give an example, an armature having two magnetic pole teeth facing each other through a gap, and a winding wound around the magnetic pole teeth, A linear motor comprising a plurality of permanent magnets having polarities in the vertical direction and arranged in the front-rear direction, wherein the movable element has a predetermined length in the front-rear direction as an array of the plurality of permanent magnets. A long pole portion having a length, and a short pole portion having a length in the front-rear direction shorter than the length in the front-rear direction of the long pole portion. It has a long pole part, and this long pole part can move relative to the armature in the front-rear direction and can reciprocate in the gap.

ADVANTAGE OF THE INVENTION According to this invention, the linear motor which can perform the attitude | position control of a needle | mover, and provision of a magnetic levitation | floating force efficiently, and the apparatus carrying this can be provided.
Problems, configurations, and effects other than those described above will become apparent from the description of the following examples.

FIG. 3 is a side sectional view of the linear motor according to the first embodiment. FIG. 3 is a perspective view of a configuration example of an armature according to the first embodiment. FIG. 3 is a side cross-sectional perspective view of a configuration example of the armature according to the first embodiment. FIG. 3 is a perspective view of an example of a magnetic pole component according to the first embodiment. FIG. 3 is a diagram illustrating an example of a magnetic pole configuration using the laminated steel plate according to the first embodiment. The front cross-sectional schematic diagram of the magnetic pole which shows the flow of the magnetic flux of the linear motor of Example 1. FIG. FIG. 3 is a side cross-sectional perspective schematic diagram illustrating the flow of magnetic flux of the linear motor according to the first embodiment. The figure which shows an example of arrangement | positioning of the armature for a drive of Example 1, and the armature for levitation | floating. The schematic diagram in the side view of FIG. FIG. 6 is a schematic diagram illustrating another configuration example of the levitating armature of the first embodiment. The figure which shows the relationship between the phase of the electric current of Example 1, and the position of a permanent magnet. The figure which shows the relationship of magnetization of the magnetic pole tooth of the drive armature of Example 1, and a motion of a needle | mover. Explanatory drawing of the repulsive force when the needle | mover of Example 1 is displaced or inclined. The figure which shows the example of the current waveform applied to the winding of (a) each armature for a drive at the time of three-phase drive. (B) The figure which shows the example of the thrust which generate | occur | produces with the electric current applied to the coil | winding of each armature for a drive. The figure which shows the positional relationship of the armature and permanent magnet in the time of Example 2 at a certain time. The figure which shows magnetization of the magnetic pole tooth of the dual-use armature at the time of FIG. The figure which shows magnetization of the magnetic pole tooth of the dual-use armature at the time of FIG. (A) The figure which shows the electric current which the coil | winding of the dual-use armature of Example 2 receives. (B) The figure which shows the phase of an electric current, and the positional relationship of a magnetic pole tooth and a permanent magnet. The figure which shows the relationship of magnetization of the magnetic pole tooth of the armature for both uses of Example 2, and the motion of a needle | mover. 4 is a configuration example of a drive circuit for a linear motor according to a second embodiment. 4 is a configuration example of a power conversion circuit according to a second embodiment. FIG. 6 is a longitudinal sectional view illustrating an example of a hermetic compressor according to a third embodiment. The perspective view except the airtight container 3 of Example 3. FIG. The perspective view of the horizontal cross section except the airtight container 3 of Example 3. FIG. The figure which shows an example which mounted the linear motor of each Example in the hermetic compressor. The longitudinal cross-sectional view of the refrigerator which has a compressor carrying the linear motor of Example 1,2.

  Hereinafter, each embodiment of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to the configuration of each embodiment described in detail below. The various components of the present invention do not necessarily have to be independent of each other. A plurality of components are formed as a single member, and a single component is formed of a plurality of members. That a certain component is a part of another component, a part of a certain component overlaps with a part of another component, and the like.

  Further, for the description of the embodiments, the terms front and rear direction, left and right direction, and up and down direction may be used, but the up and down direction is not necessarily parallel to the gravity direction. The front-rear direction, the left-right direction, or any other direction is allowed to be parallel to the direction of gravity.

<Outline of configuration of linear motor>
FIG. 1 is a side sectional view of the linear motor according to the first embodiment. The linear motor 100 according to the present embodiment includes a stator 5 and a mover 6 that are relatively movable in the front-rear direction (left-right direction in FIG. 1).
The stator 5 has an armature 9, and each armature 9 has a magnetic pole 7 that is a magnetic body. The magnetic pole 7 has magnetic pole teeth 70, and the armature 9 has two magnetic pole teeth 70 (hereinafter also referred to as “magnetic pole tooth sets”) arranged to face each other with a gap in the vertical direction. . These two magnetic pole teeth 70 are connected by an iron core 7e positioned in the left-right direction of the gap and extending in the up-down direction (see, for example, FIG. 2). The mover 6 is disposed in this gap and is movable relative to the stator 5. A winding 8 is wound around each magnetic pole tooth 70. When a current is passed through the winding 8, the magnetic pole teeth 70 are magnetized to generate polarity. Note that the number of armatures 9 constituting the stator 5 is arbitrary as long as one or more driving armatures 9a (U phase) and one or more levitation armatures 9b (M phase) described later are included (for example, FIG. 9).

  A nonmagnetic spacer 11 is inserted between the armatures 9. Examples of non-magnetic materials include austenitic stainless steel, aluminum alloys, resin materials such as ceramics and engineering plastics.

A plurality of permanent magnets 2 are arranged on the mover 6 side by side in the front-rear direction. The permanent magnets 2 preferably have substantially the same length in the front-rear direction, and more preferably have a flat plate shape and substantially the same shape.
Each of the plurality of permanent magnets 2 has a polarity (N pole and S pole) in the vertical direction. The arrangement of the permanent magnets 2 arranged on the mover 6 includes a short pole portion 2c and a long pole portion 2s (see, for example, FIG. 9).

  Next, the structure of the armature 9 will be described with reference to FIGS. FIG. 2 is a perspective view of a configuration example of the armature 9 according to the first embodiment. FIG. 3 is a side cross-sectional perspective view of a configuration example of the armature 9 according to the first embodiment.

  As an example of the configuration of the armature 9, one having two magnetic poles 7 and a bridge 10 inserted between the two magnetic poles 7 can be cited. The distance between the two magnetic poles 7 can be defined by the thickness of the bridge 10. The bridge 10 may be a magnetic body or a non-magnetic body, but it is preferable that the bridge 10 is a magnetic body because a three-dimensional magnetic flux path to be described later can be configured. For this reason, below, the case where the bridge | bridging 10 is a magnetic body is demonstrated.

  Of the magnetic poles 7, the magnetic pole teeth adjacent to each other via the bridge 10 are wound so that the polarity differs between the magnetic pole teeth adjacent to or opposite to a certain magnetic pole tooth, and the polarity is the same between the magnetic pole teeth diagonally opposite to each other. The direction of 8 and the current flowing through the winding 8 are controlled. For example, referring to FIG. 3, when the magnetic pole teeth 70a have N poles, the magnetic pole teeth 70b facing the magnetic pole teeth 70a, the adjacent magnetic pole teeth 70c have S poles, and the diagonally opposite magnetic pole teeth 70d have N poles. It has become. Since the bridge 10 of this embodiment is a magnetic body, the magnetic poles 7 adjacent in the front-rear direction are magnetically connected via the bridge 10, and a magnetic flux path passing through a plane parallel to the front-rear direction is formed as will be described later. .

  FIG. 4 is a perspective view illustrating an example of a magnetic pole component according to the first embodiment. FIG. 5 is a diagram illustrating an example in which a magnetic pole is formed by the laminated steel plates according to the first embodiment. When constructing a linear motor, it is desired to have a structure in which assembling is easy and many windings can be wound.

Here, the magnetic pole 7 of the armature 9 has a structure that can be divided for each magnetic pole tooth, as shown in FIG. This structure makes it easy to wind the winding 8. Further, more windings 8 can be wound, and the thrust with respect to the current can be increased. That is, the linear motor can be reduced in size.
Of course, the magnetic poles 7 constituting the armature 9 may be integrated as shown in FIG. In this case, the assembly process can be shortened.
The magnetic pole 7 has a structure in which electromagnetic steel plates 31 are laminated, and the lamination direction is the traveling direction of the mover 6. Thereby, the iron loss of a stator can be suppressed and it becomes possible to provide a highly efficient linear motor.

<Three-dimensional magnetic flux path>
Next, the magnetic flux flowing in the magnetic pole 7 will be described with reference to FIGS. FIG. 6 is a schematic front sectional view of the linear motor of this embodiment, and FIG. 7 is a schematic side sectional view of the linear motor of this embodiment.

  The solid line and broken line arrows in FIGS. 6 and 7 show an example of the flow of magnetic flux when the linear motor is driven. Note that the direction of the flow of magnetic flux is not limited to that shown in the figure because it can be reversed depending on the direction of the current flowing through the winding 8.

  When a current is passed through the winding 8 so that each magnetic pole tooth 70 has the polarity as described above, a magnetic flux flow is generated in the magnetic pole 7 mainly as shown by solid line arrows in FIGS. The magnetic flux penetrates through the upper and lower opposing magnetic pole teeth 70 and forms a loop that penetrates through the iron core 7e that connects the magnetic pole teeth located on both sides. This magnetic flux flow (loop) is in a plane perpendicular to the moving direction (front-rear direction) of the mover 6.

  In this embodiment, the magnetic pole 7 has a structure in which electromagnetic steel plates are laminated in the moving direction of the mover 6, and the plane of the electromagnetic steel plate and the plane including the main magnetic flux flow (loop) in the magnetic pole 7 are the same or parallel. By doing so, eddy currents generated in the electromagnetic steel sheet are suppressed, and loss due to eddy currents is prevented.

In the driving armature 9a of the present embodiment, the bridge 10 is made of a magnetic material, thereby forming an auxiliary magnetic flux flow (loop) as shown in FIG. 7 (broken arrows in FIG. 7). . By constructing a three-dimensional magnetic circuit in this way, magnetic flux saturation of the magnetic pole can be prevented.
Accordingly, high thrust can be generated.

<Overview of each armature>
FIG. 8 is a diagram illustrating an example of the arrangement of the driving armature 9a and the floating armature 9b. FIG. 9 is a schematic diagram in a side view of FIG.

  The driving armature 9a of the present embodiment has two magnetic pole tooth sets connected by a magnetic bridge 10, while the levitating armature 9b has a single magnetic pole tooth set. However, it is not intended to limit the structure of both. For example, both armatures only need to have one magnetic pole tooth set connected by the iron core 7 e and the winding 8 wound around the magnetic pole tooth 70. However, for the levitating armature 9b, when the magnetic pole permanent magnet 2b is provided, the winding 8 can be omitted.

As shown in FIG. 8, the linear motor of this embodiment applies a driving armature 9 a that applies an alternating current such as a sine wave or a rectangular wave to apply thrust to the mover 6, and applies a magnetic levitation force to the mover 6. It has a levitation armature 9b. Hereinafter, for description, in the driving armature 9a, the two magnetic pole teeth 70 farther from the levitation armature 9b than the bridge 10 are referred to as a first magnetic pole tooth set, and closer to the levitation armature 9b than the bridge 10. The two magnetic pole teeth 70 are referred to as a second magnetic pole tooth set.
The driving armature 9a of the present embodiment is an armature 9 having two magnetic pole tooth groups. This is because, as shown in FIG. 7, it is possible to generate high thrust by preventing the magnetic flux saturation of the magnetic poles by constructing the flow of magnetic flux (magnetic circuit) in three dimensions. . Of course, the driving armature 9a may be constituted by one magnetic pole tooth set.
Further, the levitating armature 9b of the present embodiment is an armature 9 having one magnetic pole tooth set from the viewpoint of miniaturization of the linear motor. The magnetic pole 7 of the levitation armature 9b may not have the magnetic pole permanent magnet 2b as shown in FIG. 9, or may have as shown in FIG. From the viewpoint of improving the thrust efficiency and miniaturization of the linear motor, the configuration of the driving armature 9a and the floating armature 9b is preferably as described above. However, as described above, the magnetic pole teeth of each armature The structure such as the number of sets is not limited to the above.

  The driving armature 9a can be opposed to the permanent magnets 2 belonging to the respective short pole portions 2c among the permanent magnets 2 provided on the mover 6. On the other hand, the levitating armature 9b can face the permanent magnet 2 belonging to the long pole portion 2s among the permanent magnets 2 provided on the mover 6.

<Details of driving armature and short pole part>
First, the driving armature 9a and the short pole portion 2c will be described in detail. For the sake of explanation, hereinafter, the first magnetic pole tooth set is also referred to as U-phase, and the second magnetic pole tooth set is also referred to as U-phase. Since the U-phase and the U-phase are adjacent magnetic poles via the bridge 10 as described above, a current flows through the windings so as to be magnetized in opposite polarities. In this embodiment, an example in which the driving armature 9a is driven in a single phase is shown. Specifically, the phase difference of the current flowing through the winding is approximately 180 °.
The permanent magnet 2 that can face the U-phase or U-phase magnetic pole teeth group constitutes two or more short pole portions 2c. Each short pole portion 2c has one or two or more permanent magnets 2 having polarities in the same direction. In the present embodiment, the mover 6 has three short pole portions 2c, and one permanent magnet 2ca, 2cb, and 2cc is disposed in each single pole portion 2c. Of course, each short pole portion 2c may be replaced with two or more permanent magnets 2 having the same polarity in each other. Thereby, each short pole part 2c has polarity in the up-down direction. Moreover, the permanent magnet 2 is arrange | positioned so that the short pole part 2c adjacent to each other may have a mutually reverse polarity.

  The lengths of the short pole portions 2c in the front-rear direction are preferably substantially the same, but may be different from each other as long as the linear motor can be controlled.

  When each short pole part 2c is comprised with the some permanent magnet 2, the space | interval of the permanent magnet 2 can not be included in the length of the short pole part 2c. That is, the sum of the lengths of the permanent magnets 2 belonging to one short pole portion 2c can be the length of this one short pole portion 2c. In the present embodiment, since the permanent magnets 2 having substantially the same shape are arranged so that the polarities are opposite to each other, the length in the front-rear direction of one permanent magnet 2 is the length of the short pole portion 2c. .

  The drive armature 9a can be opposed to at least the short pole portion 2c of the permanent magnet 2 provided on the mover 6. The U-phase and U-phase are magnetized by the current flowing through the winding 8 to generate a repulsive force and an attractive force with the short pole part 2c, and a thrust in the front-rear direction is applied to the mover 6 to reciprocate as desired. Can be made. This point will be further described.

<Applying thrust to the mover>
FIG. 11 is a diagram for explaining the relationship between the phase of the current flowing through the winding 8 of the U-phase upper magnetic pole teeth and the position of the permanent magnet 2 of the mover 6. In the drawing, three permanent magnets 2a, 2b, and 2c belonging to the short pole portion are depicted as the permanent magnets 2, but the number is of course not limited thereto. In order to explain the driving principle of the linear motor, as an example, it is assumed that a sine wave with a period of 2π flows through the winding 8.

  In the linear motor of the present embodiment, when the current phase is 0, the center of the magnetic pole teeth faces the permanent magnet 2b. Similarly, when the phase is π / 2, the center of the magnetic pole teeth faces the permanent magnets 2b and 2c. When the phase is −π / 2, the center of the magnetic pole teeth faces the permanent magnets 2a and 2b. When the phase is π, the center of the magnetic pole teeth faces the permanent magnet 2c. When the phase is −π, the center of the magnetic pole teeth faces the permanent magnet 2a.

  Thus, the linear motor of the present embodiment is a synchronous motor configured such that the magnetic pole teeth face each other between two permanent magnets at the phase ± π / 2 where the current amplitude is the largest. is there. Further, the magnetic pole teeth 70 of the driving armature 9a are configured to face the permanent magnet 2 when the phase of the sine wave is the smallest, ie, 0, ± π. With this configuration, since the magnetic pole teeth face each other between the permanent magnets when the magnetization is large, the permanent magnet 2 of the mover 6 has a large magnetic attraction force or repulsive force in the relative movement direction (front-rear direction). Can receive.

  FIG. 12 is a diagram for explaining the relative motion between the mover and the stator. In FIG. 12, as an example, the case where the mover 6 moves toward the right side of the drawing is shown. Since the amplitude of the sine wave is small when the phases θ = 0 and π shown in FIGS. 12A and 12C, the U-phase magnetic pole teeth are hardly magnetized. When θ = π / 2 and (3π) / 2 shown in FIGS. 12B and 12D, since the amplitude of the sine wave is large, the magnetization of the U-phase magnetic pole teeth is strong. As described above, since the magnetic pole teeth face each other between the permanent magnets at this time, a large thrust can be given to the mover 6.

As described above, the lower magnetic pole teeth of the U phase have a magnetization opposite to that of the upper magnetic pole teeth. At this time, since the pole of the permanent magnet 2 facing the lower magnetic pole teeth of the U phase is also opposite to the magnetic pole facing the upper magnetic pole teeth of the U phase, it is movable as in the description of FIGS. Thrust can be given to the child 6.
By adjusting the distance between the U phase and the U-phase, the U-phase can be configured to give the same thrust to the mover 6 as the U-phase. As the driving armature 9a, a V-phase, a W-phase, a V-phase, and a W-phase may be provided in addition to the three-phase driving. Further, the current waveform flowing through the winding 8 of the driving armature 9a is not limited to a sine wave, and may be a rectangular wave, for example.

<Details of levitating armature and long pole part>
Next, the levitation armature 9b (M phase) and the long pole portion 2s will be described in detail.
As described above, the driving armature 9 a that is magnetized by the alternating current flowing through the winding 8 can give a thrust to the mover 6. However, it is difficult for the driving armature 9a to sufficiently apply a force (magnetic levitation force) for holding the mover 6 between the magnetic pole teeth. For this reason, in this embodiment, the levitation armature 9b is provided, and thereby the magnetic levitation force is applied.
The long pole portion 2s can oppose the M-phase magnetic pole tooth set. The long pole portion 2s has one permanent magnet 2 or two or more permanent magnets 2 arranged with the same polarity, and the length of the long pole portion 2s in the front-rear direction is the length of the short pole portion 2c in the front-rear direction. Longer than length. In the present embodiment, since the long pole portion 2s is composed of one permanent magnet 2sa, the length in the front-rear direction is the length of the long pole portion 2s.

When there are a plurality of types of short pole portions 2c, the long pole portion 2s can be made longer than the longest short pole portion 2c.
When the long pole portion 2s is constituted by a plurality of permanent magnets 2, the length of the long pole portion 2s may or may not include the interval between the permanent magnets 2. That is, in the latter case, the sum of the lengths of the permanent magnets 2 belonging to the long pole portion 2s is the length of the long pole portion 2s. In the former case, the length of the long pole portion is obtained by adding the sum of the lengths of the permanent magnets 2 belonging to the long pole portion 2s to the sum of the lengths of the permanent magnets 2 belonging to the long pole portion 2s. .
In the latter case, the effects described in this embodiment are naturally obtained. In the former case, the effects described in this embodiment can be obtained by adjusting the interval and the degree of magnetization of the permanent magnet 2. For example, if the permanent magnet 2 having magnetization stronger than the magnetization of the permanent magnet 2 belonging to the short pole portion 2c is used, the effect of this embodiment can be obtained even if an appropriate interval is provided. Thus, by making the length of the long pole portion 2s longer than the length of the short pole portion 2c, a magnetic levitation force can be applied over the entire reciprocating motion of the mover 6, as will be described below.

  Further, it is preferable that the levitation armature 9b (M phase) is provided on both sides (front side and rear side) of the drive armature 9a in that the magnetic levitation of the mover 6 can be efficiently performed.

<Applying magnetic levitation force to the mover>
A current is passed through the M-phase winding 8 so that a magnetic field in the direction opposite to the direction of the magnetic field generated by the long pole portion 2s is generated (see, for example, FIG. 9). This current may have a constant magnitude, or may have a time-varying magnitude in the same direction. Thereby, a repulsive force (magnetic levitation force) in the vertical direction is generated in the mover 6 via the long pole portion 2s. As a result, as will be described later, the magnetic head is finally held at a substantially intermediate position that is magnetically balanced. That is, the mover 6 is magnetically levitated and can be magnetically supported on the shaft. Thereby, friction loss can be reduced and the linear motor 100 can be driven with high efficiency.

  Further, as shown in FIG. 10, when the M phase has the magnetic pole permanent magnet 2b, the amount of current flowing through the winding 8 can be reduced. The polarity of the magnetic pole permanent magnet 2b is arranged so that a magnetic field in the direction opposite to the direction of the magnetic field generated by the long pole portion 2s is generated. If the winding 8 is wound around the M phase and a current that generates a reverse magnetic field with the long pole portion 2s is passed, the magnetic levitation force can be actively controlled with a small amount of current. The winding 8 may not be provided depending on the degree of magnetization of the magnetic pole permanent magnet 2b.

In order to obtain a magnetic levitation force stably, the length Lm of the permanent magnet 2s facing the M phase, the length (stack thickness) Ls of the M phase armature, and the moving length (stroke) Lsl of the mover (see FIG. 9) Can be configured to satisfy the following equations 1 and 2.
[Equation 1] Lm ≧ Ls
[Expression 2] Lsl ≦ Lm−Ls

  By adopting a configuration that satisfies the above equation, the M-phase armature can always face the long pole portion 2s. That is, the magnetic levitation force can be obtained stably.

<Permanent magnet located at the boundary between the long pole and short pole>
The directions of the polarities of the adjacent long pole permanent magnet 2 and short pole permanent magnet 2 (in this embodiment, the permanent magnets 2cc and 2sa) are not limited. However, when these polarities are opposite to each other, the permanent magnet 2sa can give a thrust to the mover 6 by adjusting the stroke. This is preferable in that the maximum stroke of the mover 6 can be made longer. In addition, the space | interval of the permanent magnet 2 of the long pole part and short pole part which mutually adjoins may be longer than the space | interval of the two permanent magnets 2 which belong to the short pole part 2c, and may be made substantially the same.
When these polarities are in the same direction, the permanent magnet 2cc may be able to face the M-phase magnetic pole teeth group.

<Motor attitude control>
FIG. 13 shows a front sectional view of the M-phase magnetic pole 7 and the permanent magnet 2 belonging to the long pole portion 2 s provided on the mover 6.
The mover 6 is normally stable between the M-phase magnetic pole teeth 70 and at a position where the repulsive force and gravity due to the M-phase are balanced. However, for example, as shown in FIG. 13 (a), when the mover is displaced upward, the distance between the permanent magnet 2 (long pole portion 2s) and the M-phase magnetic pole teeth is shortened. The sum of the repulsive forces that can be used is downward. Therefore, the mover moves downward. Conversely, as shown in FIG. 13B, when the mover is displaced downward, the repulsive force applied to the mover 6 becomes upward. Therefore, the mover moves upward.

  As a result, the mover 6 is held at a substantially intermediate position that is magnetically balanced. That is, the mover 6 is magnetically levitated and can be magnetically supported on the shaft. Thereby, friction loss can be reduced and the linear motor 100 can be driven with high efficiency.

Further, as shown in FIG. 13C, the mover 6 may be tilted (rotated) with respect to the reciprocating direction. FIG. 13C shows an example where the mover 6 is tilted clockwise. Here, the mover 6 has a flat plate-shaped portion having a predetermined length in the left-right direction, and a permanent magnet 2sa belonging to the long pole portion 2s is disposed here.
In this embodiment, the length (width) of the permanent magnet 2sa in the left-right direction is longer than the length in the vertical direction of the gap between the M-phase two magnetic pole teeth 70 (FIG. 13 illustrates the force acting on the mover 6). For the sake of explanation, the length of the gap in the vertical direction is drawn long (see FIG. 8 as an example of the actual arrangement relationship). For this reason, when the mover 6 is inclined, a difference occurs in the magnitude of the vertical repulsive force received from the magnetized magnetic pole teeth 70 at the end of the mover, and the force for correcting the inclination is received. The width in the left-right direction of the M-phase magnetic pole teeth 70 is preferably the same as or slightly shorter than the width in the left-right direction of the permanent magnet 2 belonging to the long pole portion 2s (see, for example, FIG. 6). If it carries out like this, the repulsive force which acts on the edge part of the permanent magnet 2 can be enlarged, and inclination compensation can be implement | achieved efficiently.
As a result, a force is applied to the mover 6 in the counterclockwise direction, and the mover is finally held horizontally.

<Effect>
According to the present embodiment, a sufficient magnetic levitation force is applied to the mover 6 that reciprocally moves in the front-rear direction by the levitating armature 9b that supplies a magnetic field in the opposite direction to the long pole portion 2s. Thereby, friction loss is suppressed and displacement of the mover 6 is compensated. Furthermore, since the permanent magnet 2 belonging to the magnetic pole teeth and the long pole portion 2s of the levitation armature 9b has a flat plate shape, the inclination and the rotation motion of the mover 6 are compensated.

Next, a linear motor according to Embodiment 2 of the present invention will be described. The linear motor of the second embodiment has the same configuration as that of the first embodiment except for the following points.
The linear motor according to the present embodiment has at least one armature 9c as the armature 9 that applies thrust and magnetic levitation force to the mover 6. Preferably, there are three or more dual-use armatures 9c. Further, when three or more dual-use armatures 9c are provided, the levitation armature 9b can be optionally provided.

  The permanent magnet 2 has a flat plate shape having a width in the left-right direction, and the portion of the mover 6 having the permanent magnet 2 is also a flat plate shape.

  By flowing a current having a phase difference of 120 degrees in electrical angle through the winding 8 of the dual armature 9c for each phase, a thrust can be generated in the reciprocating direction of the mover 6. In this embodiment, since three-phase driving is performed, controllability is excellent and control by vector control or the like is possible.

<Three-phase drive by sine wave>
Before describing the current flowing through the winding 8 of the dual armature 9c of the present embodiment, a case of three-phase driving using the three driving armatures 9a described in the first embodiment will be described. That is, three-phase driving in which a sine wave current is supplied to each of the three driving armatures 9a will be described. Hereinafter, for explanation, each driving armature 9a is referred to as a U phase, a V phase, and a W phase.

  FIG. 14A is a diagram showing an example of a current waveform applied to the winding of each driving armature 9a by three-phase driving, and FIG. 14B is a diagram showing each driving armature 9a by three-phase driving. It is a figure which shows the example of the thrust which generate | occur | produces with the electric current applied to the coil | winding.

  During three-phase driving, each current generates a thrust that is half-wave rectified by these currents. As a result, the mover 6 of the linear motor 100 receives a thrust (total thrust) obtained by summing the thrusts of all phases.

  Attention is paid to a rectangular portion surrounded by a long two-dot chain line in FIG. The phase where the current waveform is near zero cross has a smaller generated thrust than the other phases. In other words, the phase with a small current has a relatively small contribution to the total thrust. In the rectangular area of FIG. 14B, the contribution of the V phase is relatively small.

  FIG. 15 shows the positional relationship between the armature 9 and the mover 6 at the time corresponding to the rectangular region of FIG. 14B during three-phase driving by a sine wave, and FIG. 16 shows the magnetization of the magnetic pole teeth of each phase at that time. Shown in The V phase having the largest area facing the permanent magnet 2 is controlled to have a small current value as described above, and is hardly magnetized.

  Such three-phase driving with a sinusoidal waveform can give a thrust to the mover 6, but it is difficult to give a sufficient magnetic levitation force. In order to apply thrust in the front-rear direction to the mover 6, it is preferable that the magnetic pole teeth 70 are magnetized when the facing area between the permanent magnet 2 and the magnetic pole teeth 70 is small, and inevitably applied in the vertical direction. This is because the force is reduced.

<Three-phase drive using shaped waveform>
Therefore, in this embodiment, a waveform as shown in FIG. 18A is formed as a current waveform applied to the winding 8 of the armature 9. The armature 9 in which such a current flows in the winding 8 is referred to as a dual armature 9c. Thereby, a magnetic levitation force can be given to the mover 6 by a phase having a large area facing the permanent magnet 2. Specifically, as shown in FIG. 17, the dual armature 9c causes the current to be generated so that the magnetism generated in the V-phase magnetic pole teeth having a large facing area is the same as that of the permanent magnet 2 facing the V-phase. Shed. That is, the V-phase armature is configured to generate a magnetic field opposite to the magnetic field of the permanent magnet 2.

  One or more dual-purpose armatures 9c may be provided, but in the present embodiment, an example of three-phase driving using three dual-purpose armatures 9c will be described as a preferred embodiment.

<Shaped current waveform flowing in each phase>
Hereinafter, the current waveform that flows through the winding 8 of the dual armature 9c that is the armature 9 of the present embodiment will be described. Hereinafter, an example in which a current waveform as shown in FIG. 18A is applied to each of the three armatures 9c will be described. Each phase is applied with a shaped waveform with a phase difference of approximately 120 °.

  In this embodiment, in order to efficiently provide the magnetic levitation force and thrust by the dual armature 9c that performs three-phase driving, a power converter (for example, PWM signal generation) that generates a current waveform as shown in FIG. Device 133). For explanation, the period of this waveform is 2π. For the sake of explanation, the direction of the current flowing through the winding 8 when the magnetic pole teeth are magnetized to the N pole is positive, and the direction when the magnetic pole teeth are magnetized to the S pole is negative. FIG. 18B shows the correspondence of the positional relationship between the magnetic pole teeth of each phase and the permanent magnet at the time corresponding to each phase of the current in FIG.

<Driving of linear motor by dual armature>
FIG. 19 shows the positional relationship and current value relationship between this phase and the permanent magnet of the mover at each time for the phase that receives the shaped waveform as shown in FIG.
For the sake of explanation, the relationship between one of the upper magnetic pole teeth of the dual armature 9c and the permanent magnet 2 (short pole portion 2c) of the mover 6 will be described with reference to FIGS. In the present embodiment, it is not always necessary to provide the above-described levitation armature 9b. In this case, the length of the permanent magnet can be one kind. That is, it is not necessary to provide both the short pole part 2c and the long pole part 2s.

  As shown in FIGS. 18A and 19A, when the phase of the current is in the vicinity of θ = 0, the current takes a relatively small positive value (small amplitude band). Further, the change in current (differential coefficient with respect to time) is substantially zero. At this time, the magnetic pole teeth are magnetized in the N pole having the same polarity as the opposing permanent magnet, and give a magnetic levitation force to the mover.

  As shown in FIGS. 18A and 19B, when the phase of the current is θ = π / 2, the current takes a relatively large positive value (large amplitude band). The change in current becomes a positive maximum before the peak θ = π / 2, becomes 0 at the peak θ = π / 2, and becomes a negative maximum after θ = π / 2. At this time, the magnetic pole teeth are opposed to each other between the permanent magnets, and give thrust to the mover.

  As shown in FIGS. 18A and 19C, when the phase of the current is in the vicinity of θ = π, the current takes a relatively small negative value (small amplitude band). Further, the change in current is substantially zero. At this time, the magnetic pole teeth are magnetized to the south pole of the same polarity as the opposing permanent magnet, and give a magnetic levitation force to the mover.

  As shown in FIGS. 18A and 19D, when the phase of the current is in the vicinity of θ = (3π) / 2, the current takes a relatively large negative value (large amplitude band). In addition, the change in current becomes a negative maximum before the peak θ = (3π) / 2, becomes zero at the peak θ = (3π) / 2, and is positive after the peak θ = (3π) / 2. Maximum. At this time, the magnetic pole teeth are opposed to each other between the permanent magnets, and give thrust to the mover.

<Characteristics of current waveform>
That is, the current waveform of the present embodiment changes the direction of the current every half cycle (phase π), and in each direction, the “small amplitude band” in which the absolute value of the current value is relatively small and the absolute value of the current value Has a relatively large “large amplitude band”. In each direction, there are two regions where the differential coefficient is substantially zero. That is, there are four regions where the differential coefficient is substantially 0 during one cycle. The current waveform of the present embodiment periodically flows in the order of the small amplitude band and the large amplitude band while changing the direction. At the boundary between the small amplitude band and the large amplitude band, there is a transition band in which the absolute value of the differential coefficient suddenly increases (in the vicinity of θ = θ1, θ2, θ3, θ4 in FIG. 18).

  As will be described later, the current waveform of this embodiment can be obtained by, for example, Pulse Width Modulation (PWM) control. Refer to the description of FIG. 20 and FIG. 21 described later for details of the method of generating such a current waveform. When a current waveform is obtained by such a method, the actual waveform becomes a jagged waveform as compared with FIG. For this reason, in order to confirm whether or not the waveform of this embodiment is used, it is preferable to smooth the current waveform to be observed by passing it through a low-pass filter in advance.

<Other features of current waveform>
A stop point or an inflection point may appear immediately before or immediately after the transition zone. In particular, as shown in FIG. 18A, at the time of transition from the small amplitude band to the large amplitude band (θ = θ1, θ3) or at the transition from the large amplitude band to the small amplitude band (θ = θ2, θ4). ) May be a stop point.

The current waveform can have, for example, one or more, two or more, three or more, or four or more stationary points during one cycle.
Since the current waveform of this embodiment has an inflection point in a large amplitude band, it has two inflection points in one cycle. Considering the transition between the small and large amplitude bands, the current waveform can have two or more inflection points.

  The inflection point is a point where the sign of the differential coefficient changes before and after the point where the differential coefficient is zero. The stationary point is a point where the sign of the differential coefficient does not change before and after the point where the differential coefficient becomes zero. However, the change in the sign includes “positive to 0”, “0 to positive”, “negative to 0”, and “0 to negative”. In addition, it is not always necessary to define the differential coefficient at that point, and a change in the sign of the differential coefficient in the vicinity of the point may be observed. Furthermore, when the differential coefficient continues to be 0 for a predetermined time, it may be considered that the two points at both ends thereof are inflection points or stationary points.

  As a method of generating current, (1) AC current (AC voltage) obtained by commercial power supply, inverter control, or the like is used as a basic waveform, and another current (voltage) is superposed separately. (2) Inverter For example, a current as shown in FIG. 18A is directly generated by control or the like.

<Synchronization of current phase and permanent magnet position>
The synchronization of the current phase and the permanent magnet position can be realized by various known techniques. For example, it can be performed as follows. First, the position of the mover is detected by a position sensor of the mover (not shown). Thereby, the electric current which flows through each phase is controllable. Similarly, the polarity of the permanent magnet facing each phase can be known using the position information of the mover. Thereby, it is possible to know the magnetization of the magnetic pole teeth 70 of each phase at each time (current value of the winding 8), the polarity of the opposing permanent magnet 2, the opposing area of the magnetic pole teeth 70 and the permanent magnet 2, and the like. That is, since it is possible to know which phase has a small contribution to the thrust, the current may be controlled by controlling the current of the winding 8 of this phase so as to have the same polarity as the opposing permanent magnet 2.

  Further, a current detection means 107 described later may be provided to detect or estimate a current value to the windings 8 of each phase, or a position of the permanent magnet 2 may be detected or estimated using a magnetic sensor. Note that the position information of the mover 6 may be estimated based on the current value to the winding 8 detected or estimated by the current detection means 107.

<Configuration example of linear motor drive device>
Next, a drive circuit for driving the three-phase linear motor according to the present embodiment will be described. A configuration example of the drive circuit is shown in FIG. The linear motor driving device 101 detects a control unit 102 that outputs an output voltage command value, a power conversion circuit 105 that outputs an AC voltage using a DC voltage source 120, and a current that flows through the linear motor 100 or the power conversion circuit 105. The current detecting means 107 is configured. The current detection means 107 can detect the current flowing through the winding 8 of the armature 9 provided in the linear motor 100.

  A detailed circuit configuration example of the power conversion circuit 105 is shown in FIG. The power conversion circuit 105 includes an inverter 121, a DC voltage source 120, and a gate driver circuit 123. The inverter 121 is configured by a switching element 122 (for example, a semiconductor switching element such as an IGBT or a MOS-FET). In these switching elements 122 (122a to 122f), two switching elements 122 are connected in series to form upper and lower arms of each phase. In the example shown in the figure, 122a and 122b are the U phase, and 122c and 122d are the V phase. The upper and lower arms of the W phase are constituted by the phases 122e and 122f.

  The connection point of the upper and lower arms of each phase is wired to the linear motor 100. When the thrust command value or the position command value is input to the voltage command value generator 103, the switching element 122 (122a to 122f) generates a voltage command value based on this and inputs the voltage command value to the PWM signal generator 133. . The PWM signal generator 133 sends a drive signal generated based on the voltage command value to the gate driver circuit 123. The drive signal has a pulse waveform. The gate driver circuit 123 sends a signal (124a to 124f) for controlling ON / OFF of each switching element 122 based on the drive signal, and the switching element 122 performs a switching operation according to the signal (124a to 124f). The voltage of the DC voltage source 120 is applied to each phase via the switching element 122. That is, the voltage applied to each phase is controlled by the switching element 122. This current waveform can be jagged as described above. For this reason, in order to check whether a drive signal or a voltage command value for commanding creation of the current waveform of this embodiment is output, it is preferable to smooth this current by passing it through a low-pass filter or the like.

  By outputting the voltage as described above, a three-phase AC voltage having an arbitrary frequency can be applied to the linear motor 100, and a waveform as shown in FIG. Further, the linear motor 100 can be driven at a variable speed, a position control drive, and a thrust control drive.

  When the shunt resistor 125 is added to the DC side of the power conversion circuit 105, it can be used for an overcurrent protection circuit for protecting the switching element 122 when an excessive current flows, a single shunt current detection method described later, and the like. .

  FIG. 21 shows a specific implementation example of the current detection unit 107 shown in FIG. The current detection unit 107 shown in FIG. 21 detects a current flowing in the U phase and the W phase among the three-phase AC currents flowing in the linear motor 100 or the power conversion circuit 105. The AC currents of all phases may be detected. However, if two of the three phases can be detected from Kirchhoff's law, the other phase can be calculated from the detected two phases.

  As another method for detecting the AC current flowing through the linear motor 100 or the power conversion circuit 105, for example, from the DC current flowing through the shunt resistor 125 added to the DC side of the power conversion circuit 105, the current on the AC side of the power conversion circuit 105 is used. There is a single shunt current detection method for detecting the current. This method utilizes the fact that a current equivalent to the alternating current of each phase of the power conversion circuit 105 flows through the shunt resistor 125 depending on the energization state of the switching elements constituting the power conversion circuit 105. Since the current flowing through the shunt resistor 125 changes with time, it is necessary to detect the current at an appropriate timing with reference to the timing at which the drive signals (124a to 124f) change. Although not shown, a single shunt current detection method may be used for the current detection means 107.

<Generates magnetic levitation force in the voltage intermediate phase>
As described above, in this embodiment, the thrust and the magnetic levitation force are obtained by one armature (one phase) using the shaped waveform. For example, the magnetic levitation force is obtained by flowing the current so that the magnetism generated in the magnetic pole teeth has the same polarity as that of the permanent magnet 2 in the phase where the current becomes near zero when sine wave driving is performed. As shown in FIG. 20, when the voltage command value is calculated to drive the linear motor, the phase where the current is near zero is the phase other than the phase where the voltage command value is the maximum and the phase where the voltage command value is the minimum. . That is, in the case of three phases as in this embodiment, a phase (intermediate phase) in which the voltage command value is intermediate corresponds. That is, a thrust is generated in which the armature 9 and the mover 6 move relative to each other in the phase where the output voltage of the power conversion circuit 105 is maximum and minimum, and the remaining phase (intermediate phase in the case of three phases) is generated. The armature 9 and the mover 6 are configured to generate a magnetic force in a direction orthogonal to the direction in which the armature 9 and the mover 6 move relatively.

<Active control of mover position>
For example, when it is desired to control the position of the mover 6 more actively, the displacement in the direction orthogonal to the direction in which the armature 9 and the mover 6 move relatively, and the inclination with the traveling direction of the mover 6 as an axis. Means 135 for detecting or estimating at least one of the following.

  For example, a proportional-integral-derivative controller (PID controller) is configured in the voltage command value generator 103 that outputs a voltage command value to be applied to the linear motor 100, and proportional to the detected or estimated displacement or inclination. By performing integral / differential control, the current of the phase in which the armature 9 has the largest area facing the permanent magnet 2 is changed. As a result, the position of the mover 6 can be actively controlled. Further, when the mover 6 is held at a substantially intermediate position or substantially parallel, the current of the phase where the armature 9 is opposed to the permanent magnet 2 is reduced, so that the efficiency can be increased. .

  As described above, the armature and the mover are relatively moved by changing the current that generates a reverse magnetic field with the permanent magnet 2 of the mover to the armature having the largest opposing area with the permanent magnet 2 of the mover. Is held at a magnetically balanced position (substantially intermediate position) in a direction orthogonal to the direction of movement of the movable element, and at the same time, the tilt around the moving direction of the mover is held at a magnetically balanced position (substantially parallel). Is done.

  In the above description, when the V-phase is close to zero current, that is, when the area where the V-phase armature is opposed to the permanent magnet 2 of the mover 6 is the largest, naturally the mover moves. The phase with the largest area where the armature faces the permanent magnet 2 also changes. In accordance with the movement of the mover in the reciprocating direction, an electric current is applied to the phase where the armature 9 is opposed to the permanent magnet 2 so that the magnetism generated in the magnetic pole teeth 70 has the same polarity as the permanent magnet 2. Thus, a magnetic levitation force can be obtained.

  In this way, by adopting a configuration in which the phase for obtaining the magnetic levitation force is sequentially changed according to the movement of the mover in the reciprocating direction, the propulsive force and the magnetic levitation force can be obtained using the same winding. The linear motor 100 can be downsized.

<Effect>
According to the present embodiment, three-phase driving can be realized by including the dual-purpose armature 9c that applies a magnetic levitation force to the movable element together with a thrust by the current converter that outputs a signal for shaping the waveform current described above. Thereby, sufficient magnetic levitation force can be given to the mover 6. In addition, when three or four dual-use armatures 9c are used, magnetic levitation force can be obtained in the same space as a normal three-phase drive motor, the linear motor can be miniaturized, and friction loss can be suppressed. it can. Further, the same effect as described in the first embodiment can be obtained.
Of course, you may have the armature 9b for levitation | floating and the armature 9a for a drive with the armature 9c for both.

Next, an example in which the linear motor according to the present invention is applied to a compressor will be described.
FIG. 22 is an example of a longitudinal sectional view of a compressor having a linear motor according to the present invention.
The hermetic compressor 50 according to the present embodiment is a reciprocating compressor in which the compression element 20 and the electric element 30 are arranged in the hermetic container 3. The compression element 20 and the electric element 30 are elastically supported in the sealed container 3 by a support spring 49.

  The compression element 20 includes a cylinder block 1 that forms a cylinder 1a, a cylinder head 16 that is assembled to an end face of the cylinder block 1, and a head cover 17 that forms a discharge chamber space. The working fluid supplied into the cylinder 1a is compressed by the reciprocating motion of the piston 4, and the compressed working fluid is sent to a discharge pipe communicating with the outside of the compressor.

FIG. 23 is a perspective view of the hermetic compressor 50 excluding the hermetic container 3, and FIG. 24 is a perspective view of a horizontal cross section of the hermetic compressor 50 excluding the hermetic container 3.
In this embodiment, a structure is adopted in which one piston 4 is connected to one end of the mover 6. Therefore, the cylinder block 1 has a structure in which one cylinder 1a is arranged.
In addition, the compression element 20 is disposed at one end of the electric element 30, and the end frame 25 is disposed on the opposite side. The cylinder block 1 and the end frame 25 have a guide rod 24 and are structured to prevent the mover 6 from contacting the magnetic pole 7.

  That is, the mover 6 reciprocates along the guide rod 24, and the guide rod 24 prevents the mover 6 from moving in a direction orthogonal to the reciprocating direction.

By applying the above-described linear motor to the electric element 30 of the present embodiment, the electric element 30 is held at a magnetically balanced position (substantially intermediate position) in a direction perpendicular to the vertical direction, and at the same time, the front-rear direction is used as an axis. The inclination is also held at a magnetically balanced position (substantially parallel).
Therefore, it is possible to reduce the friction loss generated in the cylinder 1a and the guide rod 24. Further, the guide rod 24 can be omitted.
Therefore, according to the present embodiment, a highly reliable and highly efficient hermetic compressor can be configured.

<Change in magnetic levitation current according to the position of the mover>
A configuration for enhancing the effect of shaft support by magnetic levitation will be described with reference to FIG. A piston 4 is attached to one end of a mover 6 having a permanent magnet 2. In the present embodiment, the magnetic levitation force can be applied by controlling the current of the levitation armature disposed on the side opposite to the piston 4. The displacement of the piston 4 is restricted by the wall surface of the cylinder 1a, whereas the displacement of the end of the movable element on the opposite side increases when the guide rod 24 is not provided. For this reason, it is possible to efficiently control the displacement and the inclination of the mover 6 by supporting the shaft by magnetic levitation on the side opposite to the one end side where the piston 4 is attached. This stabilizes the behavior of the piston 4 and simplifies the control. Further, since one side of the mover 6 is supported by the piston 4, the mover 6 can be efficiently supported without providing the flying armature 9 b between the driving armature and the piston 4. For this reason, it is preferable from a viewpoint of size reduction. Of course, if a levitation armature is provided also in this part, the magnetic levitation force can be applied more efficiently.

From the viewpoint of reliability and strength maintenance, the pressure vessel 3 is desired to be as small as possible. Therefore, it is desired to make the electric element 30 as a main component as small as possible, and naturally high efficiency is also desired.
By configuring the electric element 30 of the present embodiment in the hermetic compressor 50, high efficiency can be achieved by obtaining high thrust and magnetic levitation force. Therefore, the power consumption of the compressor can be reduced by using the linear motor described in each embodiment. The linear motor or hermetic compressor of the present invention can also be applied to various devices including refrigeration and air conditioning equipment such as room air conditioners and refrigerators, and greatly improves the system efficiency of these devices. Can do.

  FIG. 26 is a longitudinal cross-sectional view of a refrigerator 60 that is an example of a device on which the linear motor of Example 1 or 2 or the compressor of Example 3 is mounted. The hermetic compressor 50 includes a cooler 66 and is mounted on a refrigerator 60 using a natural refrigerant R600a having a small warming coefficient, for example. The internal space composed of the refrigerator compartment 62, the upper freezer compartment 63, the lower freezer compartment 64, and the vegetable compartment 65 is cooled by operating a refrigeration cycle (not shown) by driving the hermetic compressor 50.

  The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  Each of the above-described configurations, functions, processing units, processing procedures, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor.

  DESCRIPTION OF SYMBOLS 1 ... Cylinder block, 1a ... Cylinder, 2, 2b, 2ca, 2cb, 2cc, 2sa ... Permanent magnet, 2c ... Short pole part, 2s ... Long pole part, 3 ... Sealed container, 4 ... Piston, 5 ... Stator, 6 ... Movable element, 7 ... Magnetic pole, 7e ... Iron core, 8 ... Winding, 9 ... Armature, 9a ... Armature for driving, 9b ... Armature for levitation, 9c ... Armature for dual use, 10 ... Bridge, 11 ... Spacer , 16 ... cylinder head, 17 ... head cover, 20 ... compression element, 22 ... top packing, 23 ... resonant spring, 24 ... guide rod, 25 ... end frame, 30 ... electric element, 40 ... discharge valve device, 49 ... support spring 50 ... Hermetic compressor, 60 ... Refrigerator, 61 ... Refrigerator body, 62 ... Refrigerated room, 63 ... Upper freezer, 64 ... Lower freezer, 65 ... Vegetable room, 66 ... Cooler, 70 ... Magnetic pole teeth, 70a ... Upper magnet of the first magnetic pole set Teeth, 70b ... lower magnetic pole teeth of the first magnetic pole tooth set, 70c ... upper magnetic pole teeth of the second magnetic pole tooth set, 70d ... lower magnetic pole teeth of the second magnetic pole tooth set, 100 ... linear motor, 101 linear Motor drive device 102... Control unit 105... Power conversion circuit 135.

In order to solve the above problems, for example, the configuration described in the claims is adopted.
The present application includes a plurality of means for solving the above-described problems. To give an example, an armature having two magnetic pole teeth facing each other through a gap, and a winding wound around the magnetic pole teeth, A linear motor comprising a plurality of permanent magnets having polarities in the vertical direction and arranged in the front-rear direction, wherein the movable element has a predetermined length in the front-rear direction as an array of the plurality of permanent magnets. And a short pole portion whose length in the front-rear direction is shorter than the length in the front-rear direction of the long pole portion, and the long pole portion is a flat plate shape having a width in the left-right direction . The armature can be opposed to the short pole portion, and can be opposed to the driving armature that generates thrust on the mover, and can be opposed to the long pole portion, and generates a magnetic levitation force on the mover. comprising a floating armature, the said Nagakyokubu, the phase in the longitudinal direction with respect to the armature Go and characterized in that the gap can be reciprocated.
As another example, an armature having two magnetic pole teeth facing each other through a gap, a winding wound around the magnetic pole teeth, and a plurality of permanent magnets having a vertical polarity Is a linear motor comprising a mover arranged in the front-rear direction, having a power converter that outputs a signal for shaping an alternating current flowing in the winding of the armature, and a waveform obtained by smoothing the alternating current Has three or more inflection points during one period, or two or more inflection points and one or more stationary points, and the waveform obtained by smoothing the alternating current is differentiated during one period. There are four areas where the coefficient is approximately 0, and after the flow direction is changed, the absolute value of the current value is compared with the small amplitude band in which the absolute value of the current value is relatively small and the differential coefficient is approximately 0 Large amplitude bands in this order.
As another example, an armature having two magnetic pole teeth facing each other through a gap, a winding wound around the magnetic pole teeth, and a plurality of permanent magnets having a vertical polarity Is a linear motor comprising: a long pole portion having a predetermined length in the front-rear direction as an array of the plurality of permanent magnets; and the long pole portion A short pole portion whose length in the front-rear direction is shorter than the length in the front-rear direction, and the long pole portion is a flat plate shape having a width in the left-right direction, and is opposed to the long pole portion as the armature And a levitating armature that generates a magnetic levitation force on the mover, and the long pole portion is capable of reciprocating in the gap by moving relative to the armature in the front-rear direction. It is characterized by.

Each of the above-described configurations, functions, processing units, processing procedures, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor.
This application includes the following technical ideas.
[Appendix 1]
An armature having two magnetic pole teeth facing each other via a gap, and a winding wound around the magnetic pole teeth;
A linear motor comprising a mover in which a plurality of permanent magnets having polarity in the vertical direction are arranged in the front-rear direction,
The mover has a long pole portion having a predetermined length in the front-rear direction as an array of the plurality of permanent magnets, and a short pole portion whose length in the front-rear direction is shorter than the length in the front-rear direction of the long pole portion, Have
The mover has the long pole portion in a flat plate-shaped portion having a width in the left-right direction,
The linear motor is characterized in that the long pole portion is relatively movable in the front-rear direction with respect to the armature, and can reciprocate in the gap.

Claims (9)

An armature having two magnetic pole teeth facing each other via a gap, and a winding wound around the magnetic pole teeth;
A linear motor comprising a mover in which a plurality of permanent magnets having polarity in the vertical direction are arranged in the front-rear direction,
The mover has a long pole portion having a predetermined length in the front-rear direction as an array of the plurality of permanent magnets, and a short pole portion whose length in the front-rear direction is shorter than the length in the front-rear direction of the long pole portion, Have
The mover has the long pole portion in a flat plate-shaped portion having a width in the left-right direction,
The linear motor is characterized in that the long pole portion is relatively movable in the front-rear direction with respect to the armature, and can reciprocate in the gap.   The linear motor according to claim 1, wherein a length of the gap in a vertical direction is shorter than a length of the long pole portion in a horizontal direction. When the length of the magnetic pole teeth in the front-rear direction is Ls, the length of the long pole portion in the front-rear direction is Lm, and the length of relative movement between the mover and the armature is Lsl, Lm and Ls are 3. The linear motor according to claim 1, wherein the linear motor is driven in a range satisfying the relationship of [Equation 1] and Lsl satisfying the relationship of [Equation 2].
[Equation 1] Lm ≧ Ls
[Expression 2] Lsl ≦ Lm−Ls   4. The linear motor according to claim 1, wherein the armature includes a permanent magnet having a direction opposite to the same polarity as the polarity of the long pole portion. 5.   5. The linear motor according to claim 1, wherein the direction of the magnetic field formed by the long pole portion is opposite to the direction of the magnetic field formed by the adjacent short pole portion. 6.   The linear motor according to claim 1, wherein a direction of current flowing in the winding is constant. Another armature having two magnetic pole teeth facing the short pole portion, and a winding wound around the two magnetic pole teeth;
A power converter that outputs a signal for shaping an alternating current flowing through the winding of the other armature;
6. The waveform obtained by smoothing the alternating current has three or more inflection points or two or more inflection points and one or more stop points in one cycle. The linear motor as described in any one. Another armature having two magnetic pole teeth facing the short pole portion, and a winding wound around the two magnetic pole teeth;
A power converter that outputs a signal for shaping an alternating current flowing through the winding of the other armature;
The waveform obtained by smoothing the alternating current is
It has four areas where the derivative is approximately 0 during one cycle,
After the flow direction is changed, it has a small amplitude band in which the absolute value of the current value is relatively small and the differential coefficient is substantially 0, and a large amplitude band in which the absolute value of the current value is relatively large in this order. The linear motor according to any one of claims 1 to 5, wherein:   The apparatus which has a linear motor as described in any one of Claims 1 thru | or 8.

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