JP4106571B2 - Linear motor - Google Patents

Description

  The present invention relates to a stepping motor, a servo motor, or a direct drive motor that mainly drives at a low speed and moves linearly.

Conventionally, it has been known that if a field of a pulse motor is given by a permanent magnet, high thrust can be obtained with a compact configuration, and various structures are considered. Among them, Japanese Patent Application Laid-Open No. Sho 63-310361 discloses an improvement in the responsiveness and damping characteristics of the mover, which can simplify lead wire processing and can be manufactured at low cost.
The structure of the linear motor is described in detail in the publication, but is generally as follows. A linear stator with a U-shaped cross-section and opened upward has two U-shaped yokes with the same cross-section arranged in parallel on the inside, and the coils are arranged in the longitudinal direction at the bottom of the yoke. It is wound. The two yokes each have two magnetic poles extending upward. A magnetic pole plate is fixed to the upper surface of each magnetic pole. Protruding pole teeth extend at equal intervals toward the other magnetic pole plate. Opposing pole teeth are staggered to form a claw pole type magnetic pole surface. There is no. The movable element supported so as to be movable in the longitudinal direction of the stator is provided with two sets of permanent magnets parallel to each other so as to face the magnetic pole surface through an air gap, and is the same as the protrusion of the magnetic pole plate. It is magnetized so that the polarity is reversed at intervals.
In such a configuration, when a two-phase sine wave current having a phase difference of 90 degrees is supplied to the coils wound around the two yokes, the mover moves over the stator by a widely known linear motor mechanism. It can move in the longitudinal direction.

However, according to the above prior art, there are the following problems.
That is, since the two yokes and the magnetic pole plate provided on the stator have the structure as described above, the yoke must be formed of a massive iron core, and the magnetic pole plate must be formed of a thin soft magnetic steel plate. Increasing the excitation current flowing through the coil causes magnetic saturation and suppresses the peak thrust of the motor, and increasing the moving speed of the mover increases the iron loss of the magnetic pole plate.
In addition, since the leakage of magnetic flux passing through the gap between the pole teeth of the pole plates that are staggered extending from the upper surfaces of the two yokes is large as a whole, the motor thrust is small with respect to the excitation current, that is, the motor constant is small. There were drawbacks.
Further, since a magnetic attractive force is generated between the stator and the mover, there is a drawback that a large load is applied to the support mechanism of the mover, and the structure is distorted to cause various adverse effects.

The present invention has been made to solve these drawbacks, and an object of the present invention is to provide a motor that is reliable and can provide high thrust.
Accordingly, the present invention includes an electromagnet that excites a pair of magnetic poles opposed via an air gap with a plurality of one-to-one coils, and the plurality of magnetic pole pairs are linearly arranged at a pitch P. , A stator configured such that the magnetic field direction of the adjacent magnetic pole pair is reversed by excitation of the coil, and permanent magnets are arranged at equal intervals at the pitch P, and the magnetic poles of the adjacent permanent magnets A linear motor including a mover having a magnetic field having a reverse direction, wherein the permanent magnet of the mover moves between the air gaps.
The invention according to claim 2 also relates to a linear motor, and includes an electromagnet that excites a pair of magnetic poles opposed via an air gap with a plurality of one-to-one coils, and the plurality of magnetic pole pairs are arranged linearly. A linear motor comprising: a stator configured as described above; and a mover in which permanent magnets are arranged at equal intervals at a pitch P, and the directions of magnetic poles of adjacent permanent magnets are opposite to each other. A plurality of pairs of opposing magnetic poles are equally spaced at the pitch P in the moving direction of the mover, and adjacent magnetic pole pairs at the pitch P are opposite in direction. .
According to a third aspect of the present invention, in the linear motor according to the first or second aspect, the permanent magnet of the mover has a rectangular cross section perpendicular to the moving direction.
According to a fourth aspect of the present invention, in the linear motor according to the first or second aspect, the permanent magnet of the mover has a rectangular cross section as viewed from a direction in which the pair of magnetic poles on the stator side faces each other. It is characterized by.
According to a fifth aspect of the present invention, in the linear motor according to the first or second aspect, the direction of the magnetic field of the magnetic pole of the permanent magnet is the direction of the magnetic field between the pair of opposing magnetic poles. Yes.
Further, the invention according to claim 6 relates to a linear motor, wherein a plurality of substantially circular electromagnet cores having a pair of magnetic poles opposed via an air gap are linearly arranged at a pitch P in the moving direction of the mover. A linear motor comprising a stator arranged in a shape and a mover in which permanent magnets are arranged at equal intervals with the pitch P, and magnetic poles of adjacent permanent magnets have opposite magnetic directions. Is wound so as to generate a magnetic field in the plurality of magnetic pole pairs, and the magnetic field directions of the adjacent magnetic pole pairs in the moving direction of the mover are reversed by the excitation of the coil.
The invention according to claim 7 relates to a linear motor, wherein a plurality of substantially annular electromagnet cores having a pair of magnetic poles opposed via an air gap are linearly arranged at a pitch P in the moving direction of the mover. A linear motor including a stationary stator and permanent movers in which permanent magnets are arranged at equal intervals at the pitch P, and the directions of magnetic poles of adjacent permanent magnets are opposite to each other. A plurality of iron cores are wound so as to generate a magnetic field, and the magnetic field direction of the adjacent magnetic pole pair in the moving direction of the mover is reversed by excitation of the coil.
The invention according to claim 8 is the linear motor according to claim 6 or 7, characterized in that the permanent magnet of the movable element moves between the air gaps.
The invention according to claim 9 relates to a linear motor, wherein a plurality of iron cores each having an air gap formed in a part of a substantially annular iron core and a pair of magnetic poles opposed via the air gap are formed. Are linearly arranged at a pitch P in the moving direction of the mover, and one coil is wound around the plurality of iron cores, and adjacent to the moving direction of the mover by excitation of the coils. It is characterized in that the magnetic pole pairs are in opposite directions.
A tenth aspect of the present invention relates to a linear motor, wherein the stator according to any one of the first to fifth aspects is a stator unit, and the plurality of stator units are linear in the moving direction of the mover. The pitch between adjacent magnetic poles of adjacent stator units is “P + P / m” (P is the pitch between magnetic poles in the stator unit, m is 2, 3, 4,...). Yes.
An eleventh aspect of the invention relates to a linear motor, wherein a plurality of stators according to any one of the sixth to eighth aspects form a stator unit, and the plurality of stator units move the mover. The pitch between adjacent magnetic poles of adjacent stator units is “P + P / m” (P is the pitch between magnetic poles in the stator unit, m is 2, 3, 4,...). It is characterized by.
A twelfth aspect of the present invention relates to a linear motor, and includes a plurality of iron cores according to the ninth aspect to form a stator unit, the plurality of stator units being linearly arranged in the moving direction of the mover, and adjacent to each other. The pitch between adjacent magnetic poles of the matching stator unit is “P + P / m” (P is the pitch between the magnetic poles in the stator unit, m is 2, 3, 4,...).

As described above, according to the present invention, since the silicon steel plates are laminated to form the C-shaped iron core or I-shaped iron core of the stator, the area of the magnetic path can be increased compared to the conventional one, Magnetic saturation hardly occurs and high thrust can be obtained. Moreover, since the silicon steel plates are laminated in the direction in which the iron cores are arranged, the leakage magnetic flux between the iron cores is small, and the reduction in thrust is minimized. If the permanent magnet of the mover is thinned, the magnetic field modulation factor increases, and thus a high thrust can be obtained.
Furthermore, since the magnetic attractive force acting between the stator and the mover is canceled by both side surfaces of the permanent magnet, the burden on the support mechanism of the mover is small, and there is an effect that the reliability of the linear motor is improved.

In this way, the stator iron core can be laminated with silicon steel sheets and the magnetic path cross section can be made larger than before, so that magnetic saturation is less likely to occur and the peak thrust of the motor is increased. can do.
In addition, since the magnetic attractive force acting between the mover and the stator is offset, the burden on the support mechanism is reduced, and the reliability can be improved and the mechanism can be simplified.
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view of a two-phase linear motor showing a first embodiment of the present invention, and FIG. 2R> 2 is a plan view with a part thereof omitted.
In the figure, reference numeral 1 denotes a base, on which stator units 21 and 22 are mounted to form a stator 2. Each of the stator units 21 and 22 includes two one-side magnet units 31A and 31B and 32A and 32B having the same configuration, and the one-side magnet unit 31A includes two iron cores 41 and 43 having the same shape. The iron core 41 is formed by laminating silicon steel plates, and an air gap is formed in a part of a substantially annular shape (as shown in FIG. 3) (upper side of one side) to form a C shape (however, the air gap is Since it is formed at the top of the iron core and not at the center of the iron core, it is not the “C” shape in the strict sense, but the “substantially C” shape is correct. A pair of magnetic poles 511 and 512 having opposing parallel magnetic pole faces form a pair of magnetic poles, and C-shaped iron cores 43 having the same shape are arranged in parallel so that the distance between the centers of the iron cores is 2P. A coil 61 is wound in common on the lower sides of both iron cores, and laid sideways so that the magnetic pole surface is on the upper side and fixed to the base 1 to form a one-side magnet unit 31A.
The magnet unit 31B is configured in the same manner, and the magnetic pole surfaces of the magnetic poles 511, 522, 531, and 542 of the C-shaped iron cores 41, 42, 43, and 44 and the magnetic pole surfaces of the magnetic poles 512, 521, 532, and 541 are linearly arranged. They face each other in parallel. The stator unit 21 and the stator unit 22 having the same configuration have a center-to-center distance of 4.5 P, and the center-to-center distance between adjacent C-shaped iron cores is 1.5 P, and their magnetic pole surfaces are the same. They are placed on a flat surface.
The permanent magnet 7 of the mover 8 moves between the air gaps between the magnetic poles 511 and 512, 521 and 522, 531 and 532, and 541 and 542 of the C-shaped iron cores 41, 42, 43, and 44. ing. Each permanent magnet 7 is a rectangular bar-shaped permanent magnet having a cross section perpendicular to the moving direction and a cross section viewed from the direction in which the stator-side magnetic poles face each other, and a plurality of these are arranged in the moving direction. These are fixed to a table (not shown). The table is supported by a support mechanism (not shown) so as to be movable in the left and right movement directions to form a movable element 8. Each permanent magnet 7 is magnetized in the direction toward each magnetic pole surface of the C-shaped iron core, and the direction of magnetization is reversed at a pitch P in the longitudinal direction.

In the above configuration, the situation when the current is supplied to the coils 61 and 62 of the stator unit 21 in the direction shown in FIG.
As shown in FIGS. 3A and 3B, the magnetic flux passing through the C-shaped iron cores 41 and 42 is added in accordance with the magnetization direction of the permanent magnet 7. Since the polarity of the permanent magnet 7 and the polarity of the magnetic pole of the C-shaped iron core facing each other through the air gap are different and magnetic attractive force is generated, the moving direction position of the mover 8 is stably held in the state of FIG. The sum of the magnetic attractive forces is canceled and becomes zero because the attractive forces of the two magnetic poles of the two C-shaped iron cores are equal and in opposite directions.
Next, the operation when switching the excitation of the stator units 21 and 22 will be described with reference to FIG. FIG. 4 shows the state of excitation of the stator 1 divided into four steps, and the state of the magnetic pole being excited is viewed from above. (A) is in the same excitation state as described with reference to FIGS. 2 and 3, and the stator magnetic poles and the mover magnetic poles facing each other have different polarities and are stably held by the magnetic attractive force. (B) shows the state when a current is supplied to the stator unit 22 in the same manner as the current supplied to the stator unit 21 in (a). For the same reason as (a), (a) On the other hand, the mover 8 is stably held at a position moved 0.5P to the right. (C) shows a state in which a current having a direction opposite to that in the case of (a) is supplied, and is stably held at a position moved to the right by 0.5P with respect to (b). (D) has shown the state which supplied the electric current of the reverse direction to the case of (b), and is stably hold | maintained in the position which moved 0.5P right with respect to (c). By switching the current for one cycle, which returns to (a) after going through the four steps from (a) to (d), the mover 8 can move to the right by 2P. It can be moved continuously to the right. Needless to say, if the current is switched in the reverse order, the movable element 8 can be moved to the left by the same mechanism.

Next, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 5A is a plan view of the linear motor of the second embodiment with a part thereof omitted, and FIG. 5B is a cross-sectional view taken along line AA ′ of FIG.
The second embodiment is similar to the first embodiment except for a part, and only different points will be described. One of the changes is that the C-shaped iron core 41 of the first embodiment is divided into a C-shaped iron core 451 and an I-shaped iron core 461, and two sets of magnetic pole surfaces 551 and 552 facing each other are parallel to each other. It is rigidly fixed to the base 1 so that it becomes.
Another change is in the mover 8, and permanent magnets 72 and 71 are directly or indirectly fixed to a table (not shown) with a nonmagnetic material 73 in between so as to be positioned between the two sets of magnetic pole surfaces. Yes. The permanent magnets 71 and 72 and the C-shaped iron core and the I-shaped iron core form a closed magnetic circuit. The C-shaped iron cores 452, 453, and 454 are the same as the C-shaped iron core 451, the I-shaped iron cores 462, 463, and 464 are the same as the I-shaped iron core 461, and the one-side magnetic pole units 33A and 33B constituted by them are the first embodiment. This corresponds to the one-side units 31A and 31B in the example.
The operation of the linear motor of the second embodiment having such a configuration is the same as that of the first embodiment because the magnetic flux generation state of the stator 2 is the same as that of the first embodiment. Compared to the first embodiment, the area of the opposing magnetic pole surfaces of the stator 2 and the mover 8 is approximately doubled, so that the thrust is doubled. In the two embodiments described above, the case where there are two one-side magnet units has been described, but three or more magnet units may be used. The two embodiments are two-phase linear motors, but three stator units are provided and the center-to-center distance is 16 P / 3, that is, the center-to-center distance between adjacent iron cores is 4 P / 3. Phase linear motor.
Similarly, if m stator units are provided and the distance between the centers is (P + P / m), an m-phase motor can be obtained. In both cases, the current is switched in both directions as in the case of the two-phase motor. Can be moved.

As described above, according to the present invention, since the silicon steel plates are laminated to form the C-shaped iron core or I-shaped iron core of the stator, the area of the magnetic path can be increased compared to the conventional one, Magnetic saturation hardly occurs and high thrust can be obtained.
Moreover, since the silicon steel plates are laminated in the direction in which the iron cores are arranged, the leakage magnetic flux between the iron cores is small, and the reduction in thrust is minimized. If the permanent magnet of the mover is thinned, the magnetic field modulation factor increases, and thus a high thrust can be obtained.
Furthermore, since the magnetic attractive force acting between the stator and the mover is canceled by both side surfaces of the permanent magnet, the burden on the support mechanism of the mover is small, and there is an effect that the reliability of the linear motor is improved.

The perspective view of the linear motor which shows 1st Example of this invention. Plan view of the first embodiment Illustration of the first embodiment Illustration of the first embodiment Structure diagram of the second embodiment

Explanation of symbols

1 Base 2 Stator 21, 22, 23, 24 Stator unit 31A, 31B, 32A, 32B, 33A, 33B, 34A, 34B One side magnet unit 41, 42, 43, 44, 451, 452, 453, 454 C type Iron cores 461, 462, 463, 464 I-type iron cores 511, 512, 521, 522, 531, 532, 541, 542, 551, 552 Magnetic poles 61, 62 Coils 7, 71, 72 Permanent magnet 73 Non-magnetic material 8 Movable element

Claims (11)

Including an electromagnet that excites a plurality of magnetic pole pairs opposed via an air gap with one coil, and the plurality of magnetic pole pairs are linearly arranged at a pitch P, and the magnetic field direction of the adjacent magnetic pole pairs is excited by the excitation of the coils And a mover in which permanent magnets are arranged at equal intervals at the pitch P, and the magnetic field directions of the magnetic poles of the adjacent permanent magnets are opposite to each other. A linear motor, wherein the permanent magnet of the mover moves between the air gaps. An electromagnet that excites a plurality of magnetic pole pairs opposed via an air gap with a single coil, and a permanent magnet that is configured such that the magnetic pole pairs are arranged in a straight line and a pitch P at equal intervals. And a mover in which the directions of the magnetic poles of the adjacent permanent magnets are opposite to each other, wherein a plurality of pairs of the opposed pair of magnetic poles are arranged in the moving direction of the mover. A linear motor having equal intervals at a pitch P and adjacent magnetic pole pairs at the pitch P in opposite directions.   The linear motor according to claim 1, wherein the permanent magnet of the mover has a rectangular cross section perpendicular to the moving direction thereof.   3. The linear motor according to claim 1, wherein the permanent magnet of the mover has a rectangular cross section viewed from a direction in which the pair of magnetic poles on the stator side is opposed to each other.   The linear motor according to claim 1, wherein the magnetic field direction of the magnetic pole of the permanent magnet is a magnetic field direction between the pair of opposing magnetic poles.   A plurality of substantially annular electromagnet cores having a pair of magnetic poles facing each other through an air gap, a stator in which the magnetic poles are linearly arranged at a pitch P in the moving direction of the mover, and permanent at equal intervals at the pitch P A linear motor having magnets arranged and movers in which the directions of the magnetic poles of adjacent permanent magnets are opposite to each other, wherein one coil is wound so as to generate a magnetic field in the plurality of iron cores. The linear motor is characterized in that the direction of the magnetic field of the pair of magnetic poles adjacent to each other in the moving direction of the mover is reversed by excitation of the coil. The linear motor according to claim 6 , wherein the permanent magnet of the mover moves between the air gaps.   A plurality of iron cores in which an air gap is formed in a part of a substantially annular iron core and a pair of magnetic poles facing each other through the air gap are formed, and the magnetic pole surfaces thereof are linearly arranged at a pitch P in the moving direction of the mover. The coils are wound at equal intervals, and one coil is wound around the plurality of iron cores, and the adjacent magnetic pole pairs in the moving direction of the mover are in opposite directions by excitation of the coils. Linear motor.   The stator according to any one of claims 1 to 5, wherein the stator unit is a stator unit, the plurality of stator units are linearly arranged in a moving direction of the mover, and a pitch between adjacent magnetic poles of adjacent stator units is set. “P + P / m” (P is the pitch between magnetic poles in the stator unit, m is 2, 3, 4,...). A plurality of stators according to claim 6 or 7 constitute a stator unit, the plurality of stator units are linearly arranged in the moving direction of the mover, and a pitch between adjacent magnetic poles of adjacent stator units is “P + P / m” (P is the pitch between magnetic poles in the stator unit, m is 2, 3, 4,...). A stator unit is formed including the plurality of iron cores according to claim 8 , wherein the plurality of stator units are linearly arranged in the moving direction of the mover, and a pitch between adjacent magnetic poles of adjacent stator units is “P + P”. / M ”(P is the pitch between the magnetic poles in the stator unit, m is 2, 3, 4,...).

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