JP2003134793A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motor which has a pole structure of a pole pitch of a large generating thrust and suitable for a reduction in size, low manufacturing and assembling costs of a permanent magnet and in which the change of a cogging force or the thrust can be reduced. SOLUTION: The linear motor comprises an armature 11 having an armature winding 15 wound on the teeth 13 of an armature core 12 and a plurality of poles 16 disposed at the distal end of the teeth 13, and an inductor 2 having inductor teeth (the pitch of the inductor teeth: λ) opposed to the armature 11 via a magnetic air gap (g), in such a manner that the armature 11 is used as a movable element and the inductor 2 is used as a stator. In the motor, the poles 16 are constituted of rugged-like permanent magnets 17b, 17c. The pitch of the protrusions of the permanent magnet is set equally to the inductor teeth pitch λ. As the permanent magnets 17b, 17c, one set of two permanent magnets having different magnetizing directions are combined and disposed at the distal ends of the teeth 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor which is required to have a small size and high thrust in the fields of semiconductor manufacturing equipment and FA equipment.

[0002]

2. Description of the Related Art Conventionally, as a linear motor which is supplied to many fields such as semiconductor manufacturing equipment and FA equipment and requires small size and high thrust, it is as shown in FIGS.
FIG. 8 is a side sectional view of a linear motor showing a conventional technique, and FIG. 9 is an enlarged view of magnetic poles in FIG. In the figure, 1 is a stator, 2 is an inductor, 3 is an inductor tooth, 10 is a mover, and 11
Is an armature, 12 is an armature core, 13 is teeth, 14 is a yoke, 15 is an armature winding, and 16 is a magnetic pole. The stator 1 of the linear motor has inductor teeth 3 (inductor tooth pitch: λ) in the longitudinal direction, and is also constituted by an inductor 2 made of a magnetic material. Further, the mover 10 includes an armature core 12 made of a magnetic material, which is integrally formed with three teeth 13 and a yoke 14 connecting them, and the teeth 13.
Three-phase (U, V, W) armature winding 15
And an armature 11 having a plurality of magnetic poles 16 (magnetic pole pitch: Pm) arranged at the tips of the teeth 13. The armature 11 is provided so as to face the inductor tooth 3 via a magnetic gap g. In addition, inductor 2
For the armature core 12, for example, laminated electromagnetic steel sheets are used. The magnetic pole 16 provided at the tip of one tooth 13 is composed of 6 poles, and the magnetic pole pitch Pm is λ / 2.
Six permanent magnets 17a are arranged so that adjacent magnets have different polarities.
Specifically, the angle θ between the magnetization directions of the adjacent permanent magnets 17a is 180 degrees, and the number of permanent magnets n used for one magnetic pole is 1. The interval between the adjacent teeth 13 is 4 × λ + λ / 3, which is the sum of the width 3 × λ of the teeth 13 and the width λ + λ / 3 between the teeth 13.

Next, the operation principle will be described. The magnetic flux of the permanent magnet 17a flows through a magnetic circuit formed by the teeth 13, the yoke 14, the magnetic gap g, and the inductor teeth 3.
Since the phase difference between the teeth 13 of each phase is 120 degrees in electrical angle, when the mover 10 is moved, magnetic fluxes having an electrical angle difference of 120 degrees interlink with each other in the armature windings 15 and the armature windings 15 Three-phase induced voltage is generated. Conversely, the armature winding 15 for each phase
When a three-phase sinusoidal current is applied to the motor, a thrust is generated as a three-phase synchronous motor, and the longitudinal direction of the stator 1 is moved in the moving direction (arrow) while the mover 10 is movably supported by a linear guide or the like (not shown). It moves linearly as a view A) (for example, Japanese Patent Publication No. 5-34901).

[0004]

By the way, in the linear motor constituted by the armature 11 and the inductor 2 as in the prior art, the pitch λ of the inductor teeth 3 is made small, and the number of inductor teeth per tooth is reduced. The greater the number, the greater the generated thrust. This is because the generated thrust portion is the inductor tooth 3 facing the tooth 13. Further, in order to reduce the size of this linear motor, λ must be reduced in order to secure the number of inductor teeth per tooth. However, in the prior art, when trying to reduce λ, the magnetic pole pitch Pm also had to be reduced, resulting in the following problems. (1) As the magnetic pole pitch Pm of the permanent magnet 17a becomes smaller, the dimensional error of the magnetic pole pitch Pm influences the accuracy of the magnetic pole pitch, resulting in the fluctuation of the cogging force or the fluctuation of the thrust. (2) The dimension of the permanent magnet 17a in the direction B (perpendicular to the paper surface) orthogonal to the moving direction A of the mover and the magnetic gap direction G is larger than the magnetic pole pitch Pm of the permanent magnet 17 and the strength of the permanent magnet itself deteriorates. However, there was an accident such as breakage of the permanent magnet 17a when the permanent magnet 17a was attached to the tip of the tooth 13 or during transportation. (3) If the dimensional control of the individual permanent magnets 17a is made strict in order to avoid the problem of (1), not only the inspection time is increased but also the yield is decreased, resulting in high cost. (4) In order to avoid the problem of (2) above, the permanent magnet 17
a is divided into a plurality of parts in a moving direction A of the mover and a direction B perpendicular to the magnetic gap direction G with respect to the magnetic pole pitch Pm, and a plurality of permanent magnets having a small size in the B direction with respect to the magnetic pole pitch Pm are shown. If it is used, it takes a long time to attach the permanent magnet, resulting in a high cost.

Further, in the linear motor shown above, the problem on the armature side is mentioned, but there is also a problem on the inductor side when the stroke is extended. Although an expensive permanent magnet is generally used for the linear motor, the permanent magnet 17a is used for the stator 1.
Since it is not attached to the inductor 2 that becomes, and is only on the armature 11 side that becomes the mover 10, it is suitable for applications with a long stroke. However, if the total length of the inductor 2 is made too long when making the stroke longer, it takes labor to transport the inductor 2, or one stamp is used when punching the electromagnetic steel sheet that is the material of the inductor by a press machine. It cannot be pulled out with and productivity is poor. In addition, there is a problem in that the accuracy of the pitch of the inductor teeth 7 is deteriorated due to warpage due to processing, and the cogging force is increased. The present invention has been made to solve the above problems, and a first object thereof is to have a magnetic pole structure having a large magnetic pole pitch and a magnetic pole pitch suitable for downsizing, and to manufacture and assemble a permanent magnet. It is an object of the present invention to provide a linear motor which is low in cost and capable of reducing fluctuations in cogging force or fluctuations in thrust. A second object is to provide a linear motor that can improve the productivity of the inductor when the stroke of the linear motor is increased and can prevent the pitch accuracy of the inductor teeth from decreasing.

[0006]

In order to solve the above problems, the present invention according to claim 1 provides an armature winding wound around a tooth of an armature core and a plurality of magnetic poles arranged at the tips of the teeth. And an inductor having inductor teeth (inductor tooth pitch: λ) provided so as to face the armature via a magnetic gap. In a linear motor in which one of the children is relatively moved and the other is a stator, the magnetic poles are composed of permanent magnets formed in an uneven shape, and the pitch of the convex portions of the permanent magnets is It is set to be equal to the inductor tooth pitch λ, and the permanent magnets are arranged by combining at least two permanent magnets having different magnetization directions as a set at each tip of the teeth. Is also characterized by Of. The present invention according to claim 2 provides
The linear motor according to claim 1, wherein the permanent magnets having different magnetization directions are arranged side by side in the moving direction of the mover. According to a third aspect of the present invention, in the linear motor according to the first or second aspect, the permanent magnets having different magnetization directions are arranged side by side in a direction orthogonal to a moving direction of the mover and a magnetic air gap direction. . According to a fourth aspect of the present invention, in the linear motor according to any one of the first to third aspects, the permanent magnet is composed of a bond magnet. The present invention of claim 5 is any one of claims 1 to 4.
In the linear motor according to the item (3), the inductor is configured to be divided in the moving direction, and an engaging portion having an uneven shape is provided on a joint surface which is a dividing portion.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. [First Embodiment] FIG. 1 is a side sectional view of a linear motor showing a first embodiment of the present invention, and FIG. 2 is a plan view of the magnetic pole of FIG. 1 as seen from below the mover. FIG. 3 is an enlarged view of the magnetic poles in FIG. 1 and shows the magnetization direction of the permanent magnet. In addition,
Description of components of the present invention that are the same as those of the conventional technique will be omitted, and different components will be described. Further, in the embodiment of the present invention, as in the prior art, an example is shown in which the armature is the mover and the inductor is the stator. The present invention is different from the prior art in the following points. The magnetic pole 16 is composed of permanent magnets 17b and 17c formed in an uneven shape, and the pitch of the convex portion of the permanent magnet is the inductor tooth pitch λ.
Is set to be equal to. Further, the concave and convex permanent magnets 17b and 17c are formed by combining two pairs of the permanent magnets having different magnetization directions at the tips of the teeth 13 respectively, and the respective convex portions are at an electrical angle of 180 degrees. They are arranged side by side in the moving direction of the mover so as to have a phase difference. In this embodiment, as compared with the conventional technique, as a condition for increasing the number of inductor teeth per tooth in order to increase the thrust generated by the linear motor, the adjacent teeth 13
The distance between them is set as 8 × λ + 2λ / 3, which is the sum of the width 6 × λ of the teeth 13 and the width 2λ + 2λ / 3 between the teeth 13.

Next, the operating principle will be described with reference to FIG. FIG. 4 is a schematic diagram showing the flow of magnetic flux due to the armature magnetomotive force in the first embodiment. Although the magnetic pole structure according to the present embodiment is different from that of the prior art, since the basic part of the operation principle is the same, duplicated operation contents will be omitted and the operation contents will be supplemented. To do. That is, it shows the flow of magnetic flux due to the armature magnetomotive force when a + direction current is applied to the U-phase armature winding 15 and a − direction current is applied to the V phase and W phase. As illustrated, the magnetic flux due to the armature magnetomotive force flows through the concave-convex permanent magnet 17b or the concave-convex permanent magnet 17c that coincides with the magnetization direction. As a result, the mover moves in the moving direction (direction of arrow A) due to the magnetic attraction between the inductor teeth 3 and the concave-convex permanent magnet 17b or the concave-convex permanent magnet 17c through which the magnetic flux generated by the armature magnetomotive force passes.

As described above, in the first embodiment, the inductor tooth pitch λ is set to half the length of the prior art (the number of inductor teeth per tooth is doubled) under the condition. , Magnetic pole 16
Is composed of concave and convex permanent magnets 17b and 17c, and the pitch of the convex portions of the permanent magnet is set to be equal to the inductor tooth pitch λ.
b and 17c have a configuration in which at least two permanent magnets having different magnetization directions are combined as a set at each tip of the teeth 13, and the concave and convex permanent magnets 17b and 17c are provided at the respective convex portions. Are arranged side by side in the moving direction of the mover so that they have an electrical phase difference of 180 degrees. Therefore, since a plurality of magnetic poles are integrally formed, the magnetic pole pitch Pm of the permanent magnet is larger than that of the conventional technique. However, the magnetic pole pitch Pm can be reduced by machining without increasing the dimension in the direction perpendicular to the paper surface.
The dimensional error of the magnetic pole pitch Pm can also be reduced. As a result, it is possible to provide a linear motor having a large thrust generated while reducing the manufacturing cost, which is a problem in the conventional technique, and reducing cogging force and thrust fluctuation. Further, with the above configuration, it is not necessary to strictly control the dimensions of the individual permanent magnets, and the inspection time at the time of assembling the permanent magnets can be shortened, so that it is possible to provide a linear motor with low assembly cost. Further, since the permanent magnets 17b and 17c having different magnetization directions are arranged side by side in the moving direction A of the mover 10, the mover 1 is arranged with respect to the magnetic pole pitch Pm.
Since a large number of permanent magnets 17b and 17c can be arranged in the moving direction A of 0, the permanent magnets 17b and 17c having an uneven shape can be set in vertical and horizontal dimensional shapes with no problem in strength.
It is possible to avoid problems such as breakage when attaching c to the tips of the teeth 13 or during transportation.

[Second Embodiment] Next, a second embodiment of the present invention will be described. FIG. 5 is a side sectional view of a linear motor showing a second embodiment of the present invention, and FIG. 6 is a plan view of the magnetic pole of FIG. 5 seen from below the mover. . The second embodiment differs from the first embodiment in that the permanent magnets 17b having different magnetization directions are
17c is arranged in the direction B orthogonal to the moving direction A of the mover 10 and the magnetic gap direction G so that the convex portions of the magnets have an electrical phase difference of 180 degrees.
Since the operating principle is the same as that of the first embodiment, its explanation is omitted.

As described above, in the second embodiment, the moving direction A of the mover 10 is set so that the permanent magnets 17b and 17c having different magnetizing directions are electrically phase-shifted by 180 degrees. Since they are arranged side by side in the direction B orthogonal to the magnetic gap direction G, the same effect as the first embodiment can be obtained. In addition to the above effects, the moving direction A of the mover 10 and the magnetic air gap direction G with respect to the magnetic pole pitch Pm dimension.
Even if the dimension in the direction B orthogonal to the
Direction A of B and direction B orthogonal to magnetic gap direction G
Since it is possible to arrange a plurality of concave and convex permanent magnets each having a short shape and different in magnetization direction, it is possible to use a permanent magnet that does not deteriorate in strength. Problems such as breakage can be avoided. Further, as compared with the prior art, the work of attaching the permanent magnet can be significantly shortened, and an inexpensive linear motor can be provided.

[Third Embodiment] Next, a third embodiment of the present invention will be described. FIG. 7 is a linear motor showing a third embodiment of the present invention, (a) is a side sectional view of an inductor,
(B) is an enlarged view of the engaging portion. The third embodiment is the first,
The difference from the second embodiment is that the inductor 2 is divided in the moving direction A, and the engaging surfaces 2a and 2b having a concave-convex shape are provided on the joint surface serving as the dividing portion. In addition,
Since the inductor tooth 3 is required to have a dimensional accuracy of the magnetic gap g with the armature 11, the division position is set between the teeth. As described above, in the third embodiment, the inductor 2 has the divided structure, so that the linear motor can be easily carried when the stroke is extended. Further, since the core shape of the inductor 2 can be punched out by a stamp with a press machine, the productivity is improved, and the warp due to processing is small, so that the pitch accuracy of the inductor teeth 3 is good and the cogging force can be reduced. .

The permanent magnet 17 shown in the above embodiment is used.
For b and 17c, for example, a bond magnet may be used. That is, when it is attempted to form irregularities such as the permanent magnets 17b and 17c, it is difficult to process with a conventionally used sintered magnet and it is not suitable for a complicated shape. The permanent magnet 1
7b and 17c can be made inexpensive. Moreover, although the inductor 2 has a split structure, this may be the inductor 2 in some cases.
There is a possibility that a dimensional error may occur due to the machining of No. 1 and the pitch accuracy of the inductor teeth 3 at the connecting portion and the gap accuracy with the armature 11 may be deteriorated. That is,
Since the engaging portion of the divided inductor 2 is large, the base 18
It is difficult to clear the right angle accuracy between the inductor and the inductor 2,
When the respective inductors 2 are connected to each other, they partially come into contact with each other, the pitch accuracy of the inductor teeth 3 is deteriorated, and the height dimension from the upper surface of the base 18 to the tip surfaces of the inductor teeth 3 is long. Therefore, it is conceivable that an error may occur in the height dimension of each inductor 2. In order to avoid such a problem, when the engaging portions 2a and 2b provided on the joint surface, which is a portion where the inductor 2 is divided, are connected to each other when the engaging portions are connected, as shown in FIG. By adjusting the dimensions of the concave-convex engaging portion by providing a minute gap 2c as shown in Fig. 4, the dimension error due to machining can be released, the surface requiring dimensional accuracy can be reduced, and the inductor teeth of the connecting portion can be reduced. The pitch of 7 can be accurately performed.
In addition, a minute gap 2 is formed between the top surface of the base 18 and the inductor 2.
When d is provided, no error occurs in the height dimension of each inductor 2. Further, in this embodiment, the armature is used as a mover,
Although the structure is such that the inductor is the stator, it goes without saying that the effect of the present invention can also be achieved if the structure is such that the armature is the stator and the inductor is the mover. Further, although an armature composed of three teeth is shown, a structure in which a plurality of them are connected to each other and fixed to the same table is the same even if one armature has a plurality of teeth. The effect can be obtained. Further, in this embodiment, the convex portion of the concave-convex permanent magnet is simply rectangular, but the permanent magnet is skewed in the moving direction A of the mover and the direction B orthogonal to the magnetic gap direction G, or the convex portion is convex. The tip of the part may be formed in an arc shape.

[0014]

The following effects can be obtained by the above structure. (1) In the first embodiment, the inductor tooth pitch λ is half the length of the prior art (twice the number of inductor teeth per tooth).
Under the conditions set in step 1, the magnetic poles are made of concave and convex permanent magnets, and the pitch of the convex portions of the permanent magnets is set to be equal to the inductor tooth pitch λ. , A structure in which at least two permanent magnets having different magnetization directions are combined as one set at each tip of each tooth, and a concave-convex permanent magnet is arranged so that each convex portion is electrically at an angle of 180 degrees. Since the plurality of magnetic poles are integrally formed because they are arranged side by side in the moving direction of the mover so as to have a phase difference, the dimension in the direction perpendicular to the paper surface with respect to the magnetic pole pitch Pm of the permanent magnet is larger than that in the prior art. The magnetic pole pitch Pm can be reduced by machining without increasing the magnetic pole pitch Pm.
The dimensional error can be reduced. As a result, it is possible to provide a linear motor having a large thrust generated while reducing the manufacturing cost, which is a problem in the conventional technique, and reducing cogging force and thrust fluctuation. Further, with the above configuration, it is not necessary to strictly control the dimensions of the individual permanent magnets, and the inspection time at the time of assembling the permanent magnets can be shortened, so that it is possible to provide a linear motor with low assembly cost. Further, since the permanent magnets having different magnetization directions are arranged side by side in the direction perpendicular to the moving direction of the mover and the magnetic gap, a large number of permanent magnets are arranged in the direction perpendicular to the moving direction of the mover and the magnetic gap with respect to the magnetic pole pitch Pm. Since they can be arranged side by side, individual concave and convex permanent magnets can be set in vertical and horizontal dimension shapes that do not pose a problem in strength, and problems such as breaking of the permanent magnets when they are attached to the tips of teeth or when they are transported are avoided. be able to. (2) The second embodiment uses permanent magnets having different magnetization directions,
Since the protrusions of the magnets are arranged side by side in the moving direction of the mover and in the direction orthogonal to the magnetic gap so that the protrusions of the magnets electrically have a phase difference of 180 degrees, the same effect as in the first embodiment can be obtained. . In addition to the above effects, the magnetic pole pitch P
Even if the dimension of the mover in the direction perpendicular to the moving direction and the magnetic gap is larger than the size of m, a permanent magnet having a short shape in the direction of the mover's moving direction and the direction perpendicular to the magnetic gap and having different magnetization directions Since a plurality of magnets can be arranged, it is possible to use a permanent magnet that does not deteriorate in strength, and it is possible to avoid problems such as breakage of the permanent magnet during attachment to the tooth tip or during transportation. Also,
Compared with the conventional technology, the work of attaching the permanent magnet can be greatly shortened, and an inexpensive linear motor can be provided. (3) In the third embodiment, the inductor is divided in the moving direction, and the engaging surface having the concave and convex portions is provided on the joint surface which is the dividing portion. Therefore, when the linear motor has a long stroke. It can be easily carried. Further, since the core shape of the inductor can be punched out by one stamp with a press machine, the productivity is improved, and the warp due to processing is small, so that the pitch accuracy of the inductor teeth is good and the cogging force can be reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view of a linear motor showing a first embodiment of the present invention.

FIG. 2 is a plan view of the magnetic pole shown in FIG. 1 as viewed from below the mover.

FIG. 3 is an enlarged view of the magnetic poles in FIG. 1, showing the magnetization direction of a permanent magnet.

FIG. 4 is a schematic diagram showing a flow of magnetic flux due to an armature magnetomotive force in the first embodiment.

FIG. 5 is a side sectional view of a linear motor showing a second embodiment of the present invention.

FIG. 6 is a plan view of the magnetic pole of FIG. 5 as seen from below the mover.

FIG. 7 is a linear motor showing a third embodiment of the present invention, in which (a) is a side sectional view of an inductor and (b) is an enlarged view of an engaging portion.

FIG. 8 is a side sectional view of a linear motor showing a conventional technique.

FIG. 9 is an enlarged view of the magnetic poles in FIG. 8, showing the magnetization direction of the permanent magnet.

[Explanation of symbols]

1 stator 2 inductor 2a Engagement part 2b Engagement part 2c gap 2d gap 3 inductor teeth 10 mover 11 armature 12 Armature core 13 Teeth 14 Yoke 15 Armature winding 16 magnetic poles 17a Permanent magnet (prior art) 17b, 17c Permanent magnet (present invention)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Oto Kiichi             2-1, Kurosaki Shiroishi, Hachiman Nishi-ku, Kitakyushu City, Fukuoka Prefecture               Yasukawa Electric Co., Ltd. (72) Inventor Mitsuhiro Matsuzaki             2-1, Kurosaki Shiroishi, Hachiman Nishi-ku, Kitakyushu City, Fukuoka Prefecture               Yasukawa Electric Co., Ltd. F term (reference) 5H641 BB10 BB18 GG03 GG04 GG12                       HH03 HH05 HH09 HH10 HH12                       HH13 HH20

Claims (5)

[Claims] 1. An armature composed of an armature winding wound around a tooth of an armature core and a plurality of magnetic poles arranged at the tips of the teeth, and opposed to the armature via a magnetic gap. An inductor tooth (inductor tooth pitch:
a linear motor having a mover that relatively moves one of the armature and the inductor and a stator as the other, wherein the magnetic poles are formed in a concavo-convex shape. The permanent magnets are formed of magnets, and the pitch of the convex portions of the permanent magnets is set to be equal to the inductor tooth pitch λ. The permanent magnets have different magnetization directions at the tips of the teeth. A linear motor characterized by arranging a combination of at least two. 2. The permanent magnets having different magnetization directions are arranged side by side in the moving direction of the mover.
Linear motor described in. 3. The linear motor according to claim 1, wherein the permanent magnets having different magnetization directions are arranged side by side in a direction orthogonal to the moving direction of the mover and the magnetic air gap direction. 4. The linear motor according to claim 1, wherein the permanent magnet is a bond magnet. 5. The structure according to claim 1, wherein the inductor is divided in the moving direction, and a concave-convex engaging portion is provided on a joint surface which is a dividing portion. The linear motor according to item.