JP2003134790A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motor in which a copper loss due to a circulating current in armature windings and a viscous damping force can be eliminated even in the case that the right and left armature windings are connected in parallel. SOLUTION: The linear motor is provided with parallel stators 111, 112 in right and left which have a plurality of fixed permanent magnets 113, and a rotor 120 in which armature windings 123, 124 are wound around an armature core 129 having right and left teeth 125. In this motor, the number of teeth of one side out of the right and left teeth 125 of the core 129 is set at N (an odd number being a multiple of 3), the number of poles of the magnets 113 facing the number of teeth N is set at P (an even number not less than 2), and the moving direction positions of the magnets 113 provided on the right and left stators 111, 112 are mutually shifted by a degree of δ=((-P)×1/2+N)×P/N×180 in an electric angle. Also, the moving direction positions of the windings 123, 124 are shifted by M=(-P)×1/2+N slot, and the same phases of the right and left windings 123, 124 are mutually connected in parallel.

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 used in FA equipment such as semiconductor manufacturing equipment and which requires high speed and high accuracy positioning.

[0002]

2. Description of the Related Art Conventionally, linear motors used in FA equipment such as semiconductor manufacturing equipment and required to perform high-speed and high-precision positioning are as shown in FIGS. 8 is a front sectional view of a conventional linear motor, and FIG. 9 is a sectional view taken along the line AA of FIG. The linear motor is a moving coil type with 3 phases and 3/8 slots for each pole and phase.
The number of teeth is N = 9, and the number of magnetic poles P of permanent magnets facing the number of teeth N = 9 is P = 8. In the figure, 2
11 is a left side stator, 212 is a right side stator, 213 is a permanent magnet, 220 is a mover, 221 is a first mover mounting member, 222 is a second mover mounting member, 223 is a left armature winding, 224 is the right armature winding, 225 is the tooth,
226 is a yoke, 227 is a through hole, 228 is a bolt, 22
Reference numeral 9 is an armature core. The linear motor includes a plurality of permanent magnets 213, which are fixed to each other in the left and right parallel stators (the left side stator 211 and the left stator 211) which are fixed to the inside so that the permanent magnets 213 are alternately and sequentially made to have different polarities along the moving direction.
And a right side stator 212) is provided. Further, the left armature winding 223 and the right armature winding 224 are wound by concentrated winding on an armature core 229 having left and right teeth 225 on the surface facing the magnet row of the permanent magnet 213 via a magnetic gap. A movable element 220 is provided. Further, the stator is rigidly fixed by another stator mounting plate (not shown). In the mover, the teeth 225 and the yoke 226 are vertically sandwiched by the first mover attachment member 221 and the second mover attachment member 222, and the through hole 2
Tightened with bolts 228 passing through 27, they are rigidly fixed to each other. Then, the first mover mounting member 121
The upper surface of the movable element 2 is fixed to a load table (not shown).
20 is movable in the longitudinal direction by a guide (not shown). In such a configuration, since the linear motor has a structure in which the left side stator 211 and the right side stator 212 are arranged on the left and right side surfaces of the mover 220, the mover 22
The magnetic attraction force generated between 0 and the stators 211 and 212 is offset on the left and right. As a result, it is not necessary to consider the magnetic attraction force applied to the mover 220, and it is possible to reduce the weight of the table on which the mover 220 is mounted and extend the life of the guide that supports the table. Further, the two stators in which the permanent magnets 213 are arranged are shifted by a half pitch, and the cogging force (the basic cycle is the magnetic pole pitch λ) generated between the mover 220 and the stators 211 and 212 is offset on the left and right, There is no speed ripple due to the cogging force, and it is possible to achieve high accuracy in constant speed feed (for example, Japanese Patent Laid-Open No. 11-26223).
No. 6).

[0003]

However, in the prior art, it is necessary to connect the left and right armature windings in parallel in order to avoid a drive voltage shortage due to an increase in induced voltage proportional to the moving speed of the linear motor. The problem like this occurred. (1) When the mover is moved at a certain speed, when the left and right armature windings are connected in parallel, a phase difference occurs in the magnetic flux interlinking the left and right armature windings facing the two stators. ,
Circulating current flows in the left and right armature windings, causing copper loss,
As a result, the temperature rise of the armature core and the thermal deformation of the mover mounting portion have occurred. (2) Further, the circulating current generates a viscous braking force proportional to the speed of the mover. Therefore, when the moving speed of the mover is high, it is necessary to increase the current to overcome the large viscous braking force. Compared with the conventional method, a large amount of copper loss was caused by the increase in current. The present invention has been made to solve the above problems, and even when the left and right armature windings are connected in parallel, copper loss and viscous braking force due to circulating current in the armature windings can be eliminated. It is an object of the present invention to provide a linear motor that can be used.

[0004]

In order to solve the above-mentioned problems, the present invention according to claim 1 is characterized in that a plurality of permanent magnets are fixed to the inside in parallel so as to be alternately different poles alternately along the moving direction. A linear motor having a stator and a mover in which armature windings are wound around an armature core having left and right teeth on a surface facing the magnet row of the permanent magnets via a magnetic gap. , Of the left and right teeth of the armature core, the number of teeth on one side is N (an odd number that is a multiple of 3),
The number of magnetic poles of the permanent magnet facing the number of teeth N is P
(Even number of 2 or more), the moving direction positions of the permanent magnets provided on the left and right stators are electrical angles with each other, and δ = ((− P) × 1/2 + N) × P / N × The armature windings, which are shifted by 180 degrees, are displaced from each other in the moving direction by M = (− P) × 1/2 + N slots. The same phase is connected in parallel. Further, according to the present invention of claim 2, in the linear motor according to claim 1, the core formed by stacking the electromagnetic steel plates punched into a substantially rectangular shape by providing concave and convex engaging portions on both side surfaces is sequentially moved. It is the one that is lined up and connected. Further, according to the present invention of claim 3, left and right parallel stators in which a plurality of permanent magnets are fixed to the inside so as to sequentially become different poles alternately along the moving direction, and a magnet array of the permanent magnets and magnetic In a linear motor including a mover formed by winding armature windings on an armature core having left and right teeth on surfaces facing each other with a gap, one of the left and right teeth of the armature core is When the number of teeth is N (even number that is a multiple of 3) and the number of magnetic poles of the permanent magnets facing the number N of teeth is P (even number of 2 or more), the stators provided on the left and right sides are provided. The positions of the permanent magnets in the moving direction are electrical angles with each other, and δ = (P × 3 / 2−N) × P / N
The positions of the armature windings on the left and right are shifted by 180 degrees, and the positions in the moving direction of the left and right armature windings are shifted by M = P × 3 / 2−N + P slots, and the same phases of the left and right armature windings are connected in parallel. It is a thing. The present invention according to claim 4 is. In the linear motor according to a third aspect of the present invention, a plurality of cores, which are formed by stacking the electromagnetic steel plates punched out in a substantially rectangular shape with concave and convex engaging portions on both side surfaces, are sequentially arranged and connected in the moving direction.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION 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, and corresponds to a cross-sectional view seen from the upper part of the linear motor taken along the line AA of FIG. This linear motor is a moving coil type linear motor in which the number of phases is 3 and the number of slots for each pole and phase is 3/8, and the number of teeth is N =
9, the number of teeth N = 9, and the number of magnetic poles of the permanent magnet P =
It is composed of 8. In the figure, 111 is a left stator, 112 is a right stator, 113 is a permanent magnet, 120 is a mover, 123 is a left armature winding, 124 is a right armature winding, 125 is teeth, 126 is a yoke, Reference numeral 127 is a through hole, and 129 is an armature core. In the present invention, a plurality of permanent magnets 113 are fixed to the inside in the left-right parallel stator fixed at an equal pitch λ along the moving direction, and to the surface facing the magnet row of the permanent magnets 113 via a magnetic gap. Armature winding 12
3, a structure provided with a mover 120 having an armature core 129 wound around it, a structure in which the stator is fixed by a stator mounting plate (not shown), and the mover is sandwiched and fixed by two mover mounting members. , Are basically the same as in the prior art. The present invention is different from the prior art in the following points. That is, of the teeth 125 on the left and right of the armature core 129, the number of teeth on one side is N
When the number of magnetic poles of the permanent magnet 113 facing the number of teeth N (an odd number that is a multiple of 3) is P (even number of 2 or more), the movement of the permanent magnet 113 provided on the left and right stators 111 and 112 is moved. The directional positions are electrical angles to each other, and δ = ((-
P) × 1/2 + N) × P / N × 180 degrees shifted,
Armature windings 123 wound to the left and right of the armature core 129,
The moving direction position of 124 is M = (− P) × 1/2 + N
The armature windings 123, 1 on the left and right are displaced by the slots.
The point is that 24 in-phase components are connected in parallel.

In the left side stator 111 and the right side stator 112 of this embodiment, the number of teeth is N = 9 and the number of teeth is N.
= 9, under the condition of the number of magnetic poles P of the permanent magnet facing P = 8,
This means that the permanent magnet 113 of the right stator 112 is displaced from the permanent magnet 113 of the left stator 111 by the following electrical angle. δ = ((− P) × 1/2 + N) × P / N × 180 degrees = (− 8 × 1/2 + 9) × 8/9 × 180 degrees = 800 degrees At this time, the electrical angle of 800 degrees is 800 degrees− 360 degrees x 2
= 80 degrees, it is 80/180 x λ =
It becomes 4/9 × λ.

Next, the method of connecting the armature windings will be described with reference to FIGS.
It will be described based on. FIG. 2 is a coil connection diagram at each slot position of the left and right armature windings according to the first embodiment,
FIG. 3 is a connection diagram of the left and right armature windings connected in parallel for each phase in the first embodiment. Here, the numbers 1 to 10 in FIG. 2 are slot numbers,
The angle below the slot number represents the electrical angle at each slot position when the electrical angle at a certain slot position is 0 degree. Then, in the right armature winding 124, the U phase is U
R, XR terminals, V phase VR, YR terminals, W phase WR, Z
It has an R terminal, and in the left armature winding 123,
The U phase has UL and XL terminals, the V phase has YL and VL terminals, and the W phase has WL and ZL terminals. These terminals are UR and UL, XR and XL, VR and VL, YR in FIG.
And YL, WR and WL, ZR and ZL are connected, and the right armature winding 124 and the left armature winding 123 are connected in parallel for each phase. As shown in the figure, the right armature winding 124 is displaced from the left armature winding 123 by M slots M = (− P) × 1/2 + N = −8 × 1/2 + 9 = 5. There is. If this is expressed in electrical angle, M × P / N × 180 degrees = 5 × 8/9 × 180 degrees = 800
That is, 800 degrees−2 × 360 degrees = 80 degrees.

Next, the principle of thrust generation will be described. The U-phase of the left armature winding 123 is composed of three coils, which are connected in series at electrical angle intervals of 160 degrees. Therefore, when the mover 120 is moved relative to the left stator 111, magnetic fluxes are linked to the three coils and an induced voltage is generated. Similarly, an induced voltage having a phase difference of 120 ° and 240 ° with respect to the U phase is also generated in the V-phase and W-phase coils arranged at 120 ° and 240 ° with respect to the U-phase. Therefore, thrust is generated in the left armature winding 123 by applying a predetermined current according to the induced voltage.
On the other hand, the right armature winding 124 is
It is shifted by 5 slots. If there is no displacement between the left side stator 111 and the right side stator 112, if the mover 120 is moved relative to the right side stator 112, an induced voltage delayed by an electrical angle of 80 degrees with respect to the left side armature winding 123 is generated. . However, the right side stator 112 is the left side stator 11
Since the electrical angle δ is shifted by 80 ° with respect to 1, the induced voltage generated in the right armature winding 124 has no phase difference. Therefore, as shown in FIG. 3, the left armature winding 123
Even if the right armature winding 124 and the right armature winding 124 are connected in parallel, no circulating current is generated there.

Next, the effect of reducing the cogging force is shown in FIG.
It will be described based on. 4A and 4B are explanatory views of the effect of reducing the cogging waveform. FIG. 4A is a cogging force waveform according to the first embodiment, and FIG. 4B is a cogging force due to a linear motor having a conventional structure in which two stators are not displaced. It is a waveform. Figure 4
According to the conventional example of (b), the respective cogging forces generated between the left and right stators and the mover are in phase with the magnetic pole pitch λ (electrical angle 180 degrees) as a basic period. Therefore, a large cogging force is generated by adding the left and right sides.
On the other hand, according to the present embodiment of FIG. 4A, the cogging force generated between the left and right stators and the mover has a phase difference of 80 electrical degrees, so the combined cogging force is significantly reduced. Has been done.

As described above, since the first embodiment has the above structure, even when the left and right armature windings are connected in parallel,
It is possible to provide a linear motor capable of eliminating the copper loss and the viscous braking force due to the circulating current that have been conventionally generated, because the circulating current is not generated. Further, the cogging force (the basic period is the magnetic pole pitch λ (electrical angle 180 degrees)) generated between the left and right stators and the mover is offset by the deviation of δ = 80 degrees, and the combined cogging force is significantly reduced. be able to.

Next, a second embodiment of the present invention will be described. FIG. 5 shows a linear motor according to a second embodiment of the present invention, which corresponds to a sectional view of the linear motor taken along the line AA of FIG. 8 as seen from above. FIG. 6 is a coil connection diagram of the left armature winding 123 and the right armature winding 124. Figure 7
FIG. 8 is a diagram showing a cogging force waveform in the second embodiment. Note that this linear motor is a moving coil type linear motor having three phases and 2/5 slots for each pole and each phase. That is, the number of teeth is N = 12, and the number of teeth is N = 1.
The number of magnetic poles of the permanent magnet facing 2 is P = 10. The difference between the second embodiment and the first embodiment is as follows. That is, of the left and right teeth 125 of the armature core 129, the number of teeth on one side is N (even number that is a multiple of 3), and the number of magnetic poles of the permanent magnet 113 facing the number N of teeth is P (even number of 2 or more). Then, the left and right stators 11
The positions in the moving direction of the permanent magnets 113 provided in Nos. 1 and 112 are electrical angles with each other, and δ = (P × 3 / 2−N) × P / N ×
The armature windings 123 and 12 on the left and right are shifted by 180 degrees
4 is shifted in the moving direction position by M = P × 3 / 2−N + P slots, and the same phase of the left and right armature windings 123 and 124 is connected in parallel. In this embodiment, the permanent magnet 11 of the left stator 111 is
3 and the shift amount δ of the permanent magnet 113 of the right stator 112, and the shift slot amount M of the left armature winding 123 and the right armature winding 124, under the conditions of N = 12 and P = 10, Is calculated as δ = (P × 3 / 2−N) × P / N × 180 degrees = (10 × 3 / 2-12) × 10/12 × 180 degrees = 450 degrees = 450 degrees−360 degrees = 90 degrees M = P × 3 / 2−N = 10 × 3 / 2-12 = 3 For the permanent magnet 113 of the left stator 111, the permanent magnet 113 of the right stator 112 is 90/180 × λ = 1/2.
It is offset by × λ. In addition, the left armature winding 123 and the right armature winding 124 are 3 × 10/12 × 180 = 9.
It is offset by 0 degrees.

As described above, the second embodiment has the above-mentioned structure. Therefore, as in the first embodiment, the phases of the induced voltages in the left armature winding 123 and the right armature winding 124 are the same and the phases are parallel to each other. Even if they are connected, no circulating current will occur. Further, since the permanent magnet 113 of the right stator 112 is displaced from the permanent magnet 113 of the left stator 111 by an electrical angle δ = 90 degrees, it occurs between the left and right stators and the mover as shown in FIG. It is possible to eliminate the synthesis of cogging force.
It is possible to further reduce the cogging force compared with δ = 80 degrees in the first embodiment.

In the above embodiments, the moving coil type linear motor has been described, but it may be configured as a moving magnet type linear motor, and the same effect as that of the moving coil type of the present invention can be obtained. Therefore, it goes without saying that it can be easily implemented as a category of design change. The armature core has been described as an example of a core punched from a magnetic steel plate into a structure in which a plurality of teeth and yokes are integrated. A plurality of cores, which are provided with joint portions and are laminated, may be sequentially arranged and connected in the moving direction. In addition, when the number of teeth N = 9, P = 8, and when the number of teeth N = 12, P = 10. However, the number of teeth N = 9.
In case of, P = 10, and in case of number of teeth N = 12, P
The same effect can be obtained by setting = 14.

[0014]

As described above, the present invention has the following effects. According to the first embodiment, of the left and right teeth of the armature core, the number of teeth on one side is N
When the number of magnetic poles of the permanent magnets facing the number of teeth N (an odd number that is a multiple of 3) is P (even number of 2 or more), the moving direction positions of the permanent magnets provided on the left and right stators are electrically different from each other. At a corner, δ = ((− P) × 1/2 + N) × P / N × 1
The position in the moving direction of the armature windings wound on the left and right of the armature core is shifted by 80 degrees, and M = (− P) × 1/2 + N
Since they are shifted by the slots and the same phases of the left and right armature windings are connected in parallel, no circulating current is generated even if the left and right armature windings are connected in parallel. Therefore, copper loss and viscous braking force due to the circulating current do not occur. Further, the cogging force having a fundamental cycle of 180 electrical degrees is canceled by δ = 80 degrees, and the cogging force can be reduced.

According to the second embodiment, of the left and right teeth of the armature core, the number of teeth on one side is N (even number that is a multiple of 3), and the number of magnetic poles of the permanent magnet facing the number N of teeth is set. When P (even number of 2 or more), the moving direction positions of the permanent magnets provided on the left and right stators are electric angles with respect to each other,
δ = (P × 3 / 2−N) × P / N × 180 ° shifted, and the moving direction positions of the left and right armature windings are M = P × 3 /
2-N + P slots are shifted and the left and right armature windings of the same phase are connected in parallel. Therefore, as in the first embodiment,
Circulating current can be eliminated. Further, since the cogging force having a basic cycle of 180 electrical degrees is δ = 90 degrees, the cogging force can be further reduced as compared with the cogging force in the first embodiment.

[Brief description of drawings]

FIG. 1 is a linear motor showing a first embodiment of the present invention and corresponds to a cross-sectional view seen from the upper portion of the linear motor taken along the line AA of FIG.

FIG. 2 is a coil connection diagram at each slot position of the left and right armature windings according to the first embodiment of the present invention.

FIG. 3 is a connection diagram of left and right armature windings connected in parallel for each phase in the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of a cogging waveform reduction effect,
(A) is a cogging force waveform according to the first embodiment, and (b) is a cogging force waveform due to a linear motor having a conventional structure in which two stators are not displaced.

FIG. 5 is a linear motor showing a second embodiment of the present invention, and corresponds to a cross-sectional view of the linear motor taken along the line AA of FIG. 8 as seen from above.

FIG. 6 is a coil connection diagram of a left armature winding 123 and a right armature winding 124 according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a cogging force waveform in the second embodiment of the present invention.

FIG. 8 is a front sectional view of a conventional linear motor.

9 is a cross-sectional view of the linear motor taken along the line AA of FIG. 8 seen from above.

[Explanation of symbols]

111 Left stator (stator) 112 Right stator (stator) 113 permanent magnet 120 mover 121 First Mover Attachment Member 122 Second Mover Attachment Member 123 Left armature winding (armature winding) 124 Right armature winding (armature winding) 125 teeth 126 Yoke 127 through hole 128 volts 129 Armature core

Claims (4)

[Claims] 1. A left-right parallel stator in which a plurality of permanent magnets are fixed inside so as to alternately and sequentially become different poles along the moving direction, and a permanent magnet array and a magnet row of the permanent magnets face each other via a magnetic gap. In a linear motor including a mover in which armature windings are wound around an armature core having left and right teeth on its surface, the number of teeth on one side of the left and right teeth of the armature core is N. When the number of magnetic poles of the permanent magnet facing the number of teeth N is P (even number of 2 or more) (moving direction of the permanent magnet provided on the left and right stators) The positions are shifted in electrical angle from each other by δ = ((− P) × 1/2 + N) × P / N × 180 degrees, and the moving direction position of the armature winding wound to the left and right of the armature core is expressed by M = (-P) x 1/2 + N slots are shifted, and the left and right electric machines are A linear motor characterized in that the same phases of the child windings are connected in parallel. 2. The armature core is formed by stacking a plurality of cores, which are laminated in order by providing concave and convex engaging portions on both side surfaces of an electromagnetic steel plate punched out in a substantially rectangular shape, in sequence in the moving direction. The linear motor according to claim 1, wherein: 3. A left-right parallel stator in which a plurality of permanent magnets are fixed inside so as to sequentially have different poles alternately along the movement direction, and a magnet row of the permanent magnets, which face each other via a magnetic gap. In a linear motor including a mover in which armature windings are wound around an armature core having left and right teeth on its surface, the number of teeth on one side of the left and right teeth of the armature core is N. (Even number that is a multiple of 3), the number of teeth N
The number of magnetic poles of the permanent magnet facing P is P (even number of 2 or more)
In this case, the moving direction positions of the permanent magnets provided on the left and right stators are displaced from each other by δ = (P × 3 / 2−N) × P / N × 180 degrees in terms of electrical angle. A linear molinear motor characterized in that the moving direction positions of the armature windings are shifted by M = P × 3 / 2−N + P slots, and the same phases of the left and right armature windings are connected in parallel. 4. The armature core is formed by connecting a plurality of cores, which are formed by stacking an electromagnetic steel plate punched out in a substantially rectangular shape with concave and convex engaging portions on both side surfaces, sequentially in the moving direction. The linear motor according to claim 3, wherein: