JP4434383B2 - Linear motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a linear motor that can be used as high-precision positioning feed in the fields of semiconductor manufacturing equipment and FA equipment, for example, and that can perform linear motion at high speed and high acceleration / deceleration to obtain high thrust.
[0002]
[Prior art]
Conventionally, a three-phase linear inductor type synchronous motor having an armature core provided with an armature winding and a permanent magnet on a mover and an inductor tooth on a stator is as shown in FIGS.
FIG. 6 is a perspective view of a conventional three-phase linear inductor type synchronous motor, and FIG. 7 is a diagram showing an arrangement of permanent magnets and stators of the mover in the three-phase linear inductor type motor. ) Is a magnetization pattern diagram of each phase permanent magnet, and (b) is a plan view of a stator facing the permanent magnet of (a).
In FIG. 6, 21 is a linear motor, 22 is a mover of the linear motor 21, 23 is an armature core formed by laminating a number of electromagnetic steel sheets punched into an E shape, 23a is an armature core tooth, and 24 is each of A thin plate-like permanent magnet provided in a row at the tip of the teeth 23a, 25 is an armature winding composed of three phases (U phase, V phase, W phase) wound around the outer periphery of the tooth portion 23a of the armature core. is there. An armature core 23 having a permanent magnet 24 and an armature winding 25 is used as a mover 22. A stator 26 of the linear motor 21 is supported by a fixed base (not shown) via a movable element 22 and a fixed gap. Reference numeral 27 denotes an elongated magnetic body having a cross section having a constant tooth width and height (yoke thickness), and constitutes an inductor tooth. Reference numeral 28 denotes a non-magnetic material, and the magnetic material 27 and the non-magnetic material 28 are alternately arranged in a sandwich and fixed as a stator 26.
The mover 22 and the stator 26 are supported by a linear guide (not shown) including a slider and a guide rail. In this case, a slider (not shown) is attached to the mover side.
Further, in FIG. 7, the permanent magnet 24 provided on the mover 22 has the same pole pair pitch as the tooth pitch of the stator 26 (interval of the magnetic body 27), and the polarities of the N pole and the S pole parallel to the gear cutting direction. Are magnetized so as to be alternately arranged, and the magnetic pole pitch of each of the three phases is given a phase difference by 1/3 pole pair pitch.
In such a linear motor, the magnetic fluxes of the permanent magnets 24 having U, V, and W poles flow through each other by the inductor teeth 27 of the stator 26. In addition, since the phase difference between the magnetic poles of each phase is 120 ° in electrical angle, when the mover 22 is moved, magnetic fluxes having a difference of 120 ° are linked to each phase winding to generate a three-phase induced voltage. Conversely, when a three-phase sinusoidal current is applied to each phase, a thrust is generated as a three-phase synchronous motor, and the mover 22 moves linearly on the stator 26 in the longitudinal direction.
[0003]
[Problems to be solved by the invention]
However, the prior art has the following problems.
(1) A large attraction force acts between the permanent magnet of the mover and the inductor teeth of the stator, and the table (not shown) provided for fixing the mover and mounting the load is bent or linear The frictional resistance of the guide (not shown) increased. In addition, if the table weight is increased in order to strengthen the table so that it does not bend, it becomes impossible to obtain a predetermined acceleration with the mover thrust generated by the linear motor.
(2) Since the stator of the linear motor has a magnetic material and a non-magnetic material arranged in a sandwich, there are places where magnetic flux easily passes and difficult to pass, so the permeance change increases and cogging with large amplitude Force will be generated. As a result, there have been problems such as vibration during high speed movement and speed fluctuation during constant speed feeding.
(3) The slot opening width at the tip of the armature tooth portion is narrow, making winding work difficult, and the space factor of the winding in the slot cannot be increased. As a result, the efficiency of the linear motor could not be improved.
(4) Due to the heat generated by the armature winding wound around the outer periphery of the armature teeth, the permanent magnet attached to the tip of the armature teeth may be peeled off and dropped.
Accordingly, the present invention provides a linear motor that can reduce attraction force and cogging force, reduce vibration during high-speed movement and speed fluctuation during constant-speed feeding, and prevents permanent magnets from peeling off and falling. With the goal.
[0004]
[Means for Solving the Problems]
In order to solve the above problem, the present invention of claim 1 is an armature core formed by laminating a number of electromagnetic steel plates through which magnetic flux passes, and is wound around the outer periphery of the tooth portion along the stacking direction of the armature core. A three-phase armature winding, a thin plate-like permanent magnet provided at the tip of the tooth portion of the armature core, and an inductor tooth made of a magnetic material and disposed opposite to the permanent magnet via a gap A linear motor that is arranged so that either the armature core or the inductor serves as a mover and the other serves as a stator, and the armature core and the inductor travel relatively. in the inductor teeth, it is provided with equally spaced every pitch λ is formed in a projecting shape on a flat plate extending toward the longitudinal direction of travel of the movable element, the armature iron core, magnetic steel The thickness direction of the inductor teeth is the pitch direction The armature core is divided for each tooth portion of the armature core, and is disposed obliquely along the pitch direction of the inductor, and is provided at the tip of each tooth. A plurality of permanent magnets are provided side by side so as to be opposed to the tooth surface of the inductor teeth so that the polarities are alternately different, and are provided side by side so as to be in the same arrangement direction as the teeth portion. Yes.
According to a second aspect of the present invention, in the linear motor according to the first aspect, the armature core is divided into 3 × M pieces (M is an integer) in a longitudinal direction in which the mover moves. The core block is composed of a plurality of core blocks, and each of the divided core blocks is arranged with an electrical angle shifted by 60 × N degrees (N is an integer).
According to a third aspect of the present invention, in the linear motor according to the first aspect, the inductors are arranged in two rows so as to sandwich the armature core therebetween along the longitudinal direction of the inductor teeth. It is characterized by that.
According to a fourth aspect of the present invention, in the linear motor according to the first aspect, the cross-sectional shape of the permanent magnet is a trapezoidal cross-sectional shape having a taper with respect to the stacking direction of the armature core, and A magnet fixing plate for preventing the permanent magnet from peeling off is provided around the permanent magnet so as to surround the permanent magnet.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a linear motor showing a first embodiment of the present invention, in which (a) is a perspective view showing the overall configuration, and (b) is a front sectional view as seen from the thrust direction. FIG. 2 is a linear motor according to the first embodiment. FIG. 2A is a cross-sectional view of the mover and the inductor as viewed from the upper surface of the linear motor along the line AA in FIG. 1, and FIG. It is a side view of the needle | mover in).
In the figure, 1 is a linear motor, 2 is a mover, 3 is an armature core formed by laminating a large number of electromagnetic steel plates, 3a is a through hole provided in the armature core 3, 3b is a yoke part of the armature core, 3c Is a tooth portion of the armature core, 4 is a thin plate provided in a row at the tip of the tooth portion 3c, a permanent magnet having a rectangular cross section, and 5 is a three-phase armature winding wound around the outer periphery of the tooth portion 3c Wire, 6 is an armature mounting guide, 7 is an armature mounting plate, 8 is a mold resin, 9 is a stator, 10 is an inductor, 10a is an inductor tooth, 11 is an inductor support base, 12 is a fixing base, 13 Is a bolt. The armature core 3 provided with the permanent magnet 4 and the armature winding 5 is used as the mover 2, the inductor 10 is used as the stator 9, and the mover 2 and the stator 9 are connected by a linear guide (not shown). The supported configuration is basically the same as the prior art.
The configuration in which the present invention differs from the prior art is as follows.
That is, the inductor 10 is formed of a magnetic body in which electromagnetic steel plates are laminated, and the protruding inductor teeth 10a are formed at equal intervals for each predetermined pitch λ on a flat plate extending in the longitudinal direction. Consists of. The two rows of inductors 10 are supported by an inductor support base 11 having an L-shaped cross section with the inductor teeth 10 a inside, and two inductor support bases 11 are fixed by a fixing base 12. is doing.
On the other hand, the armature core 3 serving as the mover is disposed so as to face the gap between the two rows of inductors 10 so that the stacking direction of the armature core 3 is orthogonal to the pitch direction of the inductor teeth 10a. ing. The armature core 3 has nine tooth portions 3c formed on the side facing the inductor 10, and each tooth portion 3c is connected by a central yoke portion 3b. The yoke portion 3b is provided with a total of five through holes 3a at equal intervals, and bolts 13 having male screws are passed through the through holes 3a located on one side of the laminated armature cores 3 to The armature mounting guide 6 having a female screw is provided on the other side of the armature core 3 thus formed, and after the bolt 13 is screwed into the armature mounting guide 6, the armature core 3 and the armature mounting guide 6 are connected and fixed. ing.
The permanent magnet 4 provided at each tooth tip 3c of the armature core 3 is composed of a set of five permanent magnets having different polarities such as N pole, S pole, N pole, etc. Nine sets are arranged on the surface of the armature core 3 so as to face the tooth surfaces of the inductor teeth 10a toward the pitch direction of 10a and attached by adhesion.
Furthermore, as shown in FIG. 2, the armature winding 5 is arranged in the order of U, V, W, U, V, W,... The periphery of the child winding 5 is fixed by a mold resin 8 having excellent thermal conductivity, for example, stycast. As described above, the armature mounting plate 7 is attached to the upper portion of the armature core 3 including the permanent magnet 4 and the armature winding 5 via the armature mounting guide 6.
Next, the operation will be described.
When the armature core that constitutes the mover of the linear motor is linearly moved along the longitudinal direction of the inductor that constitutes the stator, the teeth of the armature core that face each other with a gap between the two rows of inductors With the configuration in which the permanent magnets are arranged side by side at the tip, a thrust acts in the moving direction of the mover, and an attractive force is generated in the direction of the gap perpendicular to the thrust direction. At this time, the linear motor travels at a predetermined acceleration with the suction forces in the two gaps acting in opposite directions to cancel each other.
[0006]
Next, a second embodiment will be described.
FIG. 3 shows a linear motor according to a second embodiment of the present invention, in which (a) is a cross-sectional view seen from the upper surface in a state where the armature mounting plate is removed, and is taken along line AA in FIG. And (b) is a side view of the mover.
The second embodiment differs from the first embodiment in that the armature core 3 of the mover is moved in the longitudinal direction of the first core block 31, the second core block 32, and the third core block 33. This is a point divided into three.
That is, each of the iron core blocks 31 to 33 has three teeth portions 3c, and the yoke portion 3b at the center of the iron core block is provided with two through holes 3a having the same shape, and bolts (not shown) are formed in the through holes 3a. The armature core 3 and the armature mounting guide (not shown) are fixed.
For each of the iron core blocks 31 to 33, the second iron core block 32 is (17/2 + 1/3) × λ and the third iron core block 33 is (17/2 + 1 /) with respect to the first iron core block 31. 3) x2λ is shifted. Expressing this in terms of electrical angle, the amount of deviation is (17/2 + 1/3) × 360 ° = 300 ° for the second core block 32 and (17/2 + 1/3) × 2 for the third core block 33. X360 ° = 240 °. Here, the armature winding 5 is wound around the tooth portion 3c of the first iron core block 31 in the order of the U phase, the V phase, and the W phase from the left side of the drawing, and the permanent magnet 4 has an N pole at the tooth tip 3c. The S pole, N pole, S pole, and N pole are attached in this order. Since the second iron core block 32 is displaced by 300 ° = 120 ° + 180 °, the armature winding 5 is wound in the order of the V phase, the W phase, and the U phase from the left side of the drawing. The poles, the S poles, the N poles, and the S poles are attached in this order. Since the third iron core block 33 is displaced by 240 °, the armature winding 5 is wound in the order of the W phase, the U phase, and the V phase from the left side of the page, and the permanent magnet 4 has an N pole, an S pole, an N pole, The S and N poles are attached in this order.
Next, the operation will be described.
In a linear motor, when an armature core disposed opposite to the inside of an inductor via a gap is linearly moved along the longitudinal direction of the inductor, a thrust is generated in the traveling direction of the armature core. In general, a cogging force tends to be generated at a longitudinal end portion of the armature core due to a magnetic unbalance, that is, a so-called end effect. However, in this case, since the first to third iron core blocks are configured to be out of phase by 300 degrees in electrical angle, each cogging force also has a phase shift of 300 degrees in electrical angle. As a result, the cogging force generated by the three core blocks is canceled by this phase shift, and the mover moves at a constant speed without causing a speed fluctuation in the moving direction.
[0007]
Next, a third embodiment will be described.
FIG. 4 is a linear motor showing a third embodiment of the present invention. FIG. 4A is a cross-sectional view as seen from the upper surface in a state where the armature mounting plate is removed, and is taken along line AA in FIG. And (b) is a side view of the mover.
The third embodiment is different from the first and second embodiments as follows.
In the armature core divided into three consisting of the first to third iron core blocks 31, 32, 33, the iron core is divided for each tooth portion formed in each iron core block and divided for each tooth portion. This is a point where the iron core is disposed obliquely toward the pitch direction of the inductor teeth.
Further, as shown in FIG. 4B, a permanent magnet provided at the tip of the tooth portion is attached obliquely so as to have the same angle as the inclination angle of the iron core. In addition, since the deviation | shift amount of the electrical angle between each iron core block is the same as the 2nd Example, description is abbreviate | omitted.
Next, the operation will be described.
In a linear motor, when the armature core is linearly moved along the longitudinal direction of the inductor, the armature core and the permanent magnet are displaced due to the displacement (inclination) of the armature core and the permanent magnet with respect to the pitch direction of the inductor teeth. The cogging force generated on the side is further reduced by the skew effect.
[0008]
Next, a fourth embodiment will be described.
FIG. 5 is a front sectional view of a linear motor viewed from the thrust direction according to the fourth embodiment of the present invention.
The fourth embodiment is different from the first, second, and third embodiments in that the shape of the permanent magnet provided at the tip of the tooth portion of the armature core is tapered in the stacking direction of the armature core. The magnet fixing plate 14 is provided to prevent the magnet from peeling off so as to surround the permanent magnet 4 while being formed with a trapezoidal cross section.
Specifically, the magnet fixing plate 14 is made of a non-magnetic material whose central portion is cut out so as to be fitted to the tapered surface of the permanent magnet. Further, both upper and lower ends of the magnet fixing plate 14 are fixed to the armature mounting guide 6 with a countersunk screw 15. Since the operation is basically the same as that of the first embodiment, the description thereof is omitted.
Therefore, in the first embodiment, since the permanent magnets are arranged side by side at the tips of the tooth portions of the armature core facing the pitch direction of the inductor teeth via the gap between the two rows of inductors, the permanent magnet and the inductor. A large suction force generated between the teeth can be offset. As a result, the frictional resistance of the linear guide can be reduced without bending the table provided for fixing the mover and mounting the load. In addition, in order to avoid bending of the table, it is not particularly necessary to increase the strength of the table itself and reduce the weight, so that a predetermined acceleration can be obtained.
In the second embodiment, the armature core is divided into first to third core blocks, and each core block is configured to have a phase shift of 300 degrees in electrical angle. The cogging force generated by can be canceled out. Thereby, the speed fluctuation in the moving direction of the mover does not occur, and the mover can be moved at a constant speed.
Furthermore, in the third embodiment, the armature core is divided into the tooth portions with respect to the pitch direction of the inductor teeth, and the divided core and the permanent magnet are arranged obliquely. This can be further reduced by the skew effect. Moreover, the efficiency of the Lini motor can be improved by increasing the space factor of the winding by dividing the armature core for each tooth portion.
Furthermore, in the fourth embodiment, the permanent magnet provided at the tip of the armature tooth portion is formed in a trapezoidal cross-sectional shape having a taper in the stacking direction of the armature core, and the magnet is peeled off so as to surround the permanent magnet. Since the magnet fixing plate for prevention is provided, even if a large amount of heat is generated in the armature winding and the temperature rises, the permanent magnet is not peeled off from the tooth surface by the magnet fixing plate and is stable. And permanent magnets can be fixed.
In the above embodiment, the armature core including the armature winding and the permanent magnet is used as the mover and the inductor is used as the mover. However, the armature core is used as the stator and the inductor is used as the mover. Needless to say, the same effect can be exhibited.
Further, the permanent magnet at the tip of the armature tooth portion is not pasted on the surface, and a groove may be provided at the tip of the armature tooth portion, and the permanent magnet may be embedded therein, and the same effect can be obtained. it can.
[0009]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
(1) As shown in the first embodiment, the permanent magnets are arranged side by side at the tips of the teeth of the armature core in the pitch direction of the inductor teeth between the two rows of inductors and the gaps. A large suction force generated between the inductor teeth can be offset. As a result, the frictional resistance of the linear guide can be reduced without bending the table provided on the mover. Further, since it is not necessary to increase the weight in order to strengthen the table, a predetermined acceleration can be obtained by the thrust generated by the linear motor.
(2) As shown in the second embodiment, the phase difference between the divided first to third iron core blocks is changed by 300 degrees in terms of electrical angle, which is caused by the end effect of the mover. Cogging force can be offset. Thereby, the speed fluctuation in the moving direction of the mover does not occur, and the mover can be moved at a constant speed.
(3) As shown in the third embodiment, the armature iron core is divided into teeth for each tooth portion with respect to the pitch direction of the inductor teeth, and the divided core and the permanent magnet are arranged obliquely. Therefore, the cogging force can be further reduced by the skew effect. Further, by dividing the armature core for each tooth portion, it is possible to improve the efficiency of the Lini motor by increasing the winding space factor.
(4) As shown in the fourth embodiment, the shape of the permanent magnet is formed in a trapezoidal cross-sectional shape having a taper with respect to the stacking direction of the armature core, and the magnet fixing plate for preventing the magnet from peeling off is a permanent magnet. Even if the armature winding generates a large amount of heat and the temperature rises, the permanent magnet does not peel off from the tooth surface and can be fixed stably. .
[Brief description of the drawings]
1A and 1B are linear motors showing a first embodiment of the present invention, in which FIG. 1A is a perspective view showing the overall configuration, and FIG. 1B is a front sectional view as seen from the thrust direction.
2A is a linear motor according to a first embodiment, and FIG. 2A is a cross-sectional view of a mover and an inductor as viewed from the upper surface of the linear motor along the line AA in FIG. 1, and FIG. It is a side view of the needle | mover in a).
FIGS. 3A and 3B show a linear motor according to a second embodiment of the present invention, in which FIG. 3A is a cross-sectional view as seen from the top surface with the armature mounting plate removed, and FIG. 3B is a side view of the mover. is there.
FIGS. 4A and 4B are linear motors showing a third embodiment of the present invention, wherein FIG. 4A is a cross-sectional view seen from the top surface with the armature mounting plate removed, and FIG. 4B is a side view of the mover. is there.
FIG. 5 is a front sectional view of a linear motor as viewed from the thrust direction according to a fourth embodiment of the present invention.
FIG. 6 is a perspective view of a conventional three-phase linear inductor type synchronous motor.
7A and 7B are diagrams showing the arrangement of permanent magnets and stators of a mover in a three-phase linear inductor type motor, wherein FIG. 7A is a magnetization pattern diagram of each phase permanent magnet, and FIG. It is a top view of the stator with respect to (a).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Linear motor 2 Movable element 3 Armature core 31 1st core block 32 2nd core block 33 3rd core block 3a Through-hole 3b yoke part 3c teeth part 4 permanent magnet 5 armature winding 6 armature attachment Guide 7 Armature mounting plate 8 Mold resin 9 Stator 10 Inductor 10a Inductor teeth 11 Inductor support base 12 Fixing base 13 Bolt 14 Magnet fixing plate 15 Countersunk screw

Claims (4)

An armature core formed by laminating a large number of electromagnetic steel sheets through which magnetic flux passes, a three-phase armature winding wound around an outer periphery of a tooth portion along the stacking direction of the armature core, and the armature core A thin plate-like permanent magnet provided at the tip of the tooth portion; and an inductor that is disposed opposite to the permanent magnet via a gap and has inductor teeth made of a magnetic material, the armature core or the inductor In a linear motor arranged such that either one of the mover is a mover and the other is a stator, the armature core and the inductor are relatively driven.
Said inductor teeth, is provided with equally spaced every pitch λ is formed in a projecting shape on a flat plate extending toward the longitudinal direction of travel of said movable element,
The armature core is provided so that the stacking direction of the electromagnetic steel sheet is orthogonal to the pitch direction of the inductor teeth, the iron core is divided for each tooth portion of the armature core, and the inductor It is arranged diagonally along the pitch direction,
A plurality of permanent magnets provided at the tips of the teeth are arranged side by side so as to face the tooth surfaces of the inductor teeth so that the polarities are alternately different, and are inclined so as to be in the same arrangement direction as the teeth. A linear motor characterized by being arranged side by side. The armature core is composed of a plurality of core blocks divided into 3 × M pieces (M is an integer) in the longitudinal direction in which the mover moves, and each of the divided core blocks is electrically angled. The linear motor according to claim 1, wherein the linear motor is shifted by 60 × N degrees (N is an integer). 2. The linear motor according to claim 1, wherein the inductors are arranged in two rows so as to sandwich the armature core therebetween along the longitudinal direction of the inductor teeth. A cross-sectional shape of the permanent magnet is a trapezoidal cross-sectional shape having a taper with respect to the stacking direction of the armature core, and a magnet fixing plate for preventing the permanent magnet from peeling off so as to surround the permanent magnet. The linear motor according to claim 1 provided around a magnet.

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