JPH1118329A - Permanent magnet type motor - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Since the winding work can be made very easy, cost reduction can be expected, and the coil end can be shortened and the coil shape is not complicated. Improvement and low loss due to the optimum coil shape and improvement of coil positioning accuracy. SOLUTION: A movable member in which a stator in which a coil is wound around an armature core 1 and a multiple of two field permanent magnets 6 on the outer peripheral surface of a yoke are fixed so that adjacent magnetic poles are magnetized to different polarities from each other. In the permanent magnet type motor having an electromagnetic configuration with the armature, the armature core 1 of the stator has a movable portion formed only by the back yoke 4 having no teeth 2 and a portion formed with the teeth 2 and the slot. The coils, which are alternately arranged in the moving direction of the armature and are formed by the armature windings of the stator, are composed of a coil 3 wound around the teeth 2 and an air-core coil 5 arranged on the back yoke 4. It is characterized by that.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet type servo motor or linear motor for the semiconductor industry or FA equipment, or a torque ripple or a thrust ripple which requires high accuracy, high speed and high response. Related to permanent magnet servo motors and linear motors for direct drive.

[0002]

2. Description of the Related Art A conventional general permanent magnet type synchronous motor is constructed by using a permanent magnet for a rotor and burying a winding in a slot provided in an armature core of a stator. However, with the use of permanent magnets with high energy products in recent years,
Although high torque can be realized, iron loss and cogging force are problems. Therefore, in order to solve these problems, an armature winding of a stator having both a winding in a slot and a winding in a gap portion is disclosed in, for example,
No. 3,154,051. Hereinafter, this prior art will be described with reference to the drawings. FIG. 12 is a front sectional view of a main part in this conventional example, and FIG. 13 is a diagram showing a winding form of a coil in the conventional example. This conventional example is a three-phase six-pole motor, and the number of slots q per phase and each pole is q = 1.
It is. Therefore, the armature core 27 has the numbers # 1 to # 18.
Up to 18 slots 29 are provided at equal intervals. The lower coil sides 22, 25 are buried in the slots 29, while the upper coil sides 23, 26 are located in the gap between the armature and the rotor.

The winding procedure is such that the lower coil side 25 of the coil is buried in the slot 29 of the slot number # 1, the coil jump t = 3, and the upper coil side 26 is located in the gap of the center line of the slot number # 4. Be placed. Also, slot number #
The upper coil side 23 of the coil
However, the current flowing therethrough is arranged in the same direction as the lower coil side 25, and the lower coil side 22 forming a pair with this is buried in the slot 29 of slot number # 16 where the coil jump t = 3. According to the above rule, the other two-phase windings are electrically connected to each other by 2/3 as shown in FIG.
They are similarly arranged with a phase difference of π. The rotor is
A mechanical gap is provided from the upper coil sides 23 and 26 provided in the gap portion, and six field permanent magnets 28 are arranged on the outer peripheral surface of the rotor core 20 at equal intervals and magnetized by magnets arranged next to each other. The directions are opposite.

[0004] A conventional general permanent magnet linear motor uses a field permanent magnet for a mover and winds an armature core of a stator. For example, in the case of a three-phase linear motor, a multiple of 3 (3 × i, i is a natural number) coils are arranged within the limited length of the stator, and the required stroke determined accordingly. The mover length capable of obtaining the above stroke has been determined. Hereinafter, a conventional example of a permanent magnet linear motor will be described with reference to the drawings. FIG. 14A is a front sectional view of a main part showing a conventional example,
FIG. 14B is a top view of the stator, and FIG. 15 is a diagram illustrating a winding form of the coil. This conventional example is a case where the number of coils q of each pole and each phase is q = 1/4. The mover 30 is fixed to a table and a guide (not shown) and is supported so as to freely move in the moving direction. The mover comprises a mover yoke 31 and a field permanent magnet 32 attached thereto. The field permanent magnets 32 have a width equal to the pole pitch λp, and a total of four field permanent magnets 32 are arranged.

Next, the stator will be described. Stator 3
Reference numeral 3 denotes a configuration in which an armature winding including an air-core coil 35 is provided on a stator yoke 34. Six air core coils 35 are arranged in all. The details are, as shown in the winding configuration diagram of FIG. 15, two U-phase, V-phase, and W-phase air-core coils. The number of turns of each air-core coil is N turns, and the length occupied by the air-core coil is λc.

[0006]

However, the conventional permanent magnet synchronous motor has the following problems. The upper coil side is disposed in the gap portion, and is integrated with the lower coil side embedded in the slot. For this reason, the coil end interferes with other coils, and it is difficult to arrange the upper coil sides in the gap portion easily and at equal intervals. The upper coil side and the lower coil side are integral coils, but the cross-sectional shape of the lower coil side embedded in the slot and the cross-sectional shape of the upper coil side of the gap may be significantly different.
The winding operation while positioning is quite complicated. If the upper coil side is misaligned in the gap due to the problem, problems such as torque ripple and rotational ripple occur. In order to make the winding operation as easy as possible for the purpose of solving the problem as much as possible, if the coil end portion is made long, the copper loss increases and the efficiency deteriorates. Since the coil end is oblique between the upper coil side and the lower coil side, compared to the coil configured by concentrated winding,
The coil end portion is long, which is also a factor that increases copper loss. The above is also a problem when a linear motor is used.

The conventional permanent magnet type linear motor has the following problems. When the length of the stator is short, the ratio of the pole pitch to the stroke is large. Therefore, the length of the rotor greatly changes only by increasing or decreasing the number of poles of the mover by one. Therefore, in order to obtain the required stroke, there has been a problem that the length of the mover is reduced and the thrust is insufficient. further,
If the current was increased in order to obtain thrust with a small mover, heat generation increased due to copper loss in the stator, and thermal deformation adversely affected positioning accuracy. An object of the present invention is to reduce the cost because the winding work can be greatly facilitated in view of the above-described problems of the related art, and can shorten the coil end, and the shape of the coil is not complicated. Therefore, it is possible to realize a low loss due to an improvement in the space factor and an optimum coil shape, a high-precision positioning due to an improvement in coil positioning accuracy, and a reduction in cogging torque.

Another object of the present invention is to provide a linear motor in which the length of the stator and the length of the mover can be freely selected according to the stroke, so that the length of the mover can be optimized. It is to solve problems such as shortage and heat generation due to copper loss.

[0009]

In order to solve the above problems, the present invention provides a stator having a coil wound around an armature core, and a multiple of two field permanent magnets adjacent to a yoke outer peripheral surface. In a permanent magnet type motor having an electromagnetic configuration with a mover whose magnetic poles are fixed so as to be magnetized to different polarities, an armature core of the stator has a portion having teeth and slots, and a back having no teeth. The portions formed only by the yokes are alternately arranged in the moving direction of the mover, and the coils formed by the armature windings of the stator are arranged on the back yoke with the coils concentratedly wound around the teeth. It is composed of the air core coil. The circumferential width of the air-core coil on the back yoke is widened to 1.2 to 1.6 times the pole pitch. Also, the radial width of the air-core coil on the back yoke is set to 0.2 to 0.2 of the pole pitch.
It is configured to be spread 6 times. Further, the center spacing of the teeth is configured such that the electrical angle is 90 degrees and the electrical angle is 30 degrees alternately.

Further, the present invention provides a stator having an armature winding and a movable element having a plurality of field permanent magnets fixed on a movable element yoke such that adjacent magnetic poles are magnetized to different polarities. In the permanent magnet linear motor with the electromagnetic configuration of
The armature winding is composed of an integral number of coils of m phases, a part of the integral number of coils of m phases is provided in the stator, and the remaining coils are provided in places other than the stator. I do.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front sectional view of a main part according to a first embodiment of the present invention. FIG. 2 is a diagram showing a winding configuration based on the star connection. The first embodiment is a three-phase, 14-pole, 12-slot motor in which the number of slots in each pole and each phase is q = 2/7. First, the stator will be described. The armature core 1 of the stator is formed by stacking silicon steel plates, and six teeth 2 (tl to t6) are formed at equal intervals. On both sides of the teeth tl to t6, twelve slots for burying the slot winding coil 3 are formed. The tooth pitch is 60 degrees in mechanical angle (7 × 60 = 420 degrees in electrical angle). Between the teeth, a cylindrical back yoke 4 (bl to b6) having no irregularities is formed on the inner peripheral surface of the armature core 1 with a slot therebetween. The center pitch of the back yoke 4 is also 60 degrees mechanical angle (7 × 60 = 420 degrees electrical angle),
The center of the teeth and the center of the back yoke have a mechanical angle of 30 degrees (electrical angle of 210 degrees).

The coils of the armature winding have teeth tl to t
6 and an air-core coil 5 disposed on the surfaces of the back yokes bl to b6, which are connected in series as shown in FIG. As shown in FIG. 2, the length of the coil end is very short as compared with the prior art because the coil jump is as small as # 1 to # 2 and there is no jump from the gap to the slot. As shown in FIG. 1, the rotor has one ring-shaped permanent magnet 6 magnetized in the radial direction at regular intervals of 14 poles. According to the configuration described above, the coil disposed in the gap portion and the slot portion as in the related art is integrated, whereas in the present embodiment, the coil side of the gap portion is eliminated, so that the coil is extremely wound. The wire work is simplified and the cost can be reduced. In addition, since the coil end is shortened by adopting the concentrated winding coil, the armature core can be enlarged. Therefore, the motor constant is improved. Further, since the arrangement of coils in which gaps are not aligned due to the complexity of the winding operation as in the prior art is eliminated, problems such as torque ripple and rotary ripple can be solved.

Next, a second embodiment will be described with reference to the drawings. FIG. 3 is a front sectional view of a main part according to a second embodiment of the present invention. The second embodiment has a three-phase 1
The number of slots per pole and phase is q
= 2/7. The rotor is the same as that shown in the first embodiment. Hereinafter, the stator will be described. The configuration is almost the same as that of the first embodiment, but is characterized in that the circumferential width of the tip of the teeth 2 and the circumferential width of the air-core coil 5 are changed. In the first embodiment, since the width of the air-core coil 5 is substantially equal to the slot pitch, the circumferential width of the air-core coil is 1.15 times the pole pitch λ. In the second embodiment, this is expanded to 1.4 times the pole pitch. In addition, the width of the tip of the tooth is reduced correspondingly by widening the air-core coil. Hereinafter, the reason for increasing the circumferential width of the air-core coil will be described.

FIG. 4 shows the winding coefficient of the air-core coil with respect to the circumferential width W / pole pitch λ of the air-core coil. Here, α indicates the ratio of the portion occupied by the windings of the air-core coil, and therefore, the circumferential width of the air-core portion is represented by αW. α is 0.6 to 0.8 in consideration of the ease of the winding operation. Second
In the embodiment, since α = 0.7, W / λ = 1.
If the circumferential width of the air-core coil is increased to be 4, the winding coefficient of the air-core coil can be maximized. Further, since the winding coefficient of the coil wound around the teeth is determined by the teeth pitch, even if the air-core coil is expanded, it is constant without any influence. Therefore, by increasing the air-core coil, the winding coefficient of the armature winding is improved, and a higher torque can be realized. Next, a third embodiment will be described with reference to the drawings. FIG. 5 is a front sectional view of a main part according to a third embodiment of the present invention.

In the third embodiment, as in the first and second embodiments, a three-phase, 14-pole, 12-slot motor is used, and the number of slots in each pole is q = 2/7. Rotor is first or second
This is the same as that shown in the embodiment. Hereinafter, the stator will be described. The configuration is almost the same as that of the first embodiment, except that the radial width H of the air-core coil 5 is 0.35 times the pole pitch in the first embodiment. Hereinafter, the reason will be described. Even if the number of turns is increased by increasing the radial width of the air-core coil, the magnetic resistance increases,
The number of interlinkage magnetic fluxes cannot be increased. Also, increasing the number of turns increases the copper loss. FIG. 6 shows the relationship of the motor constant with respect to the radial width H of the air-core coil / (the outer radius r of the permanent magnet × the pole pitch λ). The motor constant is expressed as torque / (copper loss) ^0.5 , which indicates the efficiency.
Lm is the magnet thickness. From this result, H / (r ·
Even if λ) is equal to or greater than 0.6, the flux linkage hardly increases, so that the copper loss is increased and the efficiency is reduced. Therefore, in the third embodiment, since the magnet thickness has a relationship of Lm / (r · λ) = 0.4, the maximum motor constant is set to H / (r · λ) = 0.35. , The motor constant has been improved.

Next, a fourth embodiment will be described with reference to the drawings. FIG. 7 is a front sectional view of a main part according to a fourth embodiment of the present invention. In the fourth embodiment, similarly to the first, second, and third embodiments, a three-phase, 14-pole, 12-slot motor is used, and the number of slots for each pole and each phase is q = 2/7. The rotor is the same as that shown in the first embodiment. Hereinafter, the stator will be described. Although the configuration is almost the same as that of the first embodiment,
The tooth pitch is changed from the first embodiment. First
In the embodiment, the tooth pitch is 60 degrees mechanical angle, but in the fourth embodiment, the teeth pitch is 60 degrees mechanical angle.
0/7 degree, mechanical angle 60-30 / 7 degree, mechanical angle 60 thirty
/ 7 degrees,... Alternately with teeth tl, t2,
.., T6 are arranged. As a result, the order of generation of the cogging torque can be doubled, so that the cogging torque can be reduced. Hereinafter, the generation principle of the cogging torque will be described.

The relationship between the cogging torque generated by one tooth and the permanent magnet 7 of the rotor and the rotation angle of the rotor is as follows.
It is generated with an electrical angle of 180 degrees as one cycle. The waveform function f _t (θe) at this time is represented by the following equation.

[0018]

(Equation 1)

Here, t is the tooth number, θe is the rotation angle (electrical angle) of the rotor, k is the harmonic order (natural number) of the cogging torque waveform, ak is the cogging torque component of order k,
The lambda _t illustrates a position of the tooth center by an electrical angle. The cogging torque generated in the rotor can be obtained by adding the above formula for all teeth.

[0020]

(Equation 2)

## EQU1 ## Here, a comparison is made between the first embodiment and the third embodiment. In the first and third embodiments, which differ in the parameters of the above equation is an electric angle lambda _t teeth t center. Since t has six teeth, there are 1 to 6. Therefore, showing the mechanical angle and the electrical angle of the lambda _t of the first and third embodiments shown in Table 1. ()
Inside is the electrical angle.

[0022]

[Table 1] By substituting the numerical values in parentheses in the table into the cogging torque equation, the order of occurrence of the cogging torque can be obtained. The result is that the first embodiment

[0023]

(Equation 3)

Thus, the lowest order is the sixth order. But,
The third embodiment is

[0025]

(Equation 4)

Thus, the minimum order is doubled to be 12th.
Therefore, the order of the cogging torque can be doubled by employing the third embodiment. In general, if the order of the cogging torque is large, the amplitude of the cogging torque is also small, which means that the cogging torque is greatly reduced. In addition, by changing the tooth pitch, the phase shift between the flux linkage of the U-phase coils tl and t4, which are concentratedly wound around the teeth tl and t4, and that of the air-core coil on the back yokes bl and b4, respectively. Although different from the first embodiment, the combined flux linkage is balanced in three phases, and there is no problem at all. Although the embodiment of the permanent magnet type motor has been described so far, it can be configured as a permanent magnet type linear motor as follows.

FIG. 8 is a front sectional view of a main part of a fifth embodiment of the present invention. The present embodiment is a three-phase motor in which the number of slots for each pole and each phase is q = 2/7. The mover 10 is arranged such that the 14 permanent magnets 12 have polarities different from the poles adjacent to each other. The stator 13 has a stator core 14 on which silicon steel sheets are laminated and nine teeth 17 and nine non-uneven back yokes 15 formed therebetween are formed at equal intervals, and the stator core is concentrated on the teeth 17 on the stator core. The wound slot wound coil 18 and the air-core coil 18 on the back yoke 15 are arranged. Therefore, the total number of poles created by the armature winding is 21 poles.
With the configuration described above, the winding operation can be easily configured without disposing the winding in the gap portion, and the copper end can be reduced by shortening the coil end. Furthermore, the presence of the back yoke, which is a part without teeth, increases the average electromagnetic gap. Therefore, the attraction force of the mover unique to the linear motor is greatly reduced, and the life of the support mechanism is improved.

In the above embodiment, the number of slots q per pole and phase
Although 2/7 is shown, it goes without saying that the present invention can be applied to other slot combinations. Further, although the permanent magnet is shown as a ring-shaped radial anisotropy, a polar anisotropic or segment-shaped isotropic or anisotropic one may be used. Further, in the permanent magnet type linear motor, it is natural that still another embodiment is possible by adopting the technical configuration as shown in the first to fourth embodiments. Next, regarding the permanent magnet linear motor, FIG.
(A) is a front sectional view of a main part in a sixth embodiment of the present invention,
FIG. 9B shows a top view of the stator. FIG.
0 is a diagram showing the winding form.

In the sixth embodiment, the number of coils of each pole and each phase q = 1
/ 4. First, the mover will be described. The mover 10 is fixed to a table and a guide (not shown),
It is supported to move freely in the direction of movement. The mover has a mover yoke 11 and a field permanent magnet 12 attached to the mover yoke 11. The field permanent magnets 12 have a width equal to the pole pitch λp, and a total of four field permanent magnets 12 are arranged. next,
The stator will be described. The stator 13 includes the air-core coil 1
9 is provided on the stator yoke 14. Five air core coils are arranged in all. As shown in the winding configuration diagram of FIG.
There are two phase air core coils and two W phase air core coils, and one V phase air core coil. The number of turns of each air-core coil is the same N turns. Although the number of V-phase armature windings is smaller than that of the other phases by N turns, the N-turn armature windings are housed in the driver as air-core coils. Therefore, the three-phase winding resistances are all equal.

The features of the present invention will be described below in comparison with the conventional example. If the number of air-core coils on the stator is K, the length λc occupied by one coil is λc = Ls / K. The pole pitch λp is as follows: λp = m · q · λc = 3λc / 4 = 3Ls / 4K. The mover length Lm is represented by Lm = P · λp = 3PLs / 4K. Therefore, the stroke L is represented by L = Ls-Lm = (1-3P / 4K) Ls. Based on the above equations, the results of comparison between the conventional example and the sixth embodiment are shown in the table.

Table. Comparison between the conventional example and the sixth embodiment (stator length Ls is constant)

[0032]

[Table 2] According to this result, the stroke is 40% of the stator length (0.4%).
× Ls) When required, the sixth embodiment is more advantageous than the conventional example because the mover length can be increased. Assuming that the thrust constant is proportional to the length of the mover, the thrust constant of the sixth embodiment is larger by about 16%. Therefore, the copper loss generated in the motor part is reduced to {1- (1 / 1.16) ² } × 100 {approximately 26}.
%.

Although the above embodiment has been described by limiting the number of coils for each pole and phase, it is needless to say that the present invention can be applied to other combinations. Further, as a seventh embodiment,
In the sixth embodiment, the coil taken out of the stator is housed in the driver. However, as shown in FIG. 12, the coil can be used as a heater for those requiring heat.

[0034]

The following effects can be expected by adopting the structure described above. In the prior art, the winding of the gap portion and the slot portion constitute one coil, so that the coil shape is complicated and the winding operation is difficult. According to the present invention, since the coil is a concentrated winding coil in which the coil side of the gap portion is eliminated, the winding operation is facilitated and the cost can be reduced. In addition, the highly accurate placement of the coil has been facilitated,
Thrust ripple can be reduced. All of the coils are concentrated winding coils. Therefore, the coil end is shortened, so that the stacking thickness can be increased and the motor constant can be improved. The presence of the back yoke increases the electromagnetic gap, thereby reducing the attraction characteristic of the linear motor. Due to the back yoke portion, the inductance is smaller and the electric response is very good as compared with a permanent magnet field motor in which windings are embedded only in general teeth. Further, since all of the armature cores are not armature cores with teeth having a high magnetic flux density, iron loss at high speed is very small. Therefore, very low-efficiency ones for high rotation speed and high speed applications can be realized. By setting the radial width and the circumferential width of the air-core coil as described in the claims, the motor constant can be improved.

Further, since the length of the stator can be adjusted as a permanent magnet type linear motor, an optimum mover length according to the stroke can be obtained. Therefore, the mover length can be optimized, the thrust constant can be improved, and the copper loss can be reduced. Further, by arranging the coil outside the stator outside the motor or using the coil as a heater, it is possible to realize an efficient coil with little heat generation without wasting the coil.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a main part according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a winding configuration by star connection according to the first embodiment of the present invention;

FIG. 3 is a front sectional view of a main part according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a winding coefficient of an air-core coil according to a second embodiment of the present invention.

FIG. 5 is a front sectional view of a main part according to a third embodiment of the present invention.

FIG. 6 is a diagram showing motor constants of an air-core coil according to a third embodiment of the present invention.

FIG. 7 is a front sectional view of a main part according to a fourth embodiment of the present invention.

FIG. 8 is a front sectional view of a main part according to a fifth embodiment of the present invention.

FIG. 9A is a front sectional view of a main part according to a sixth embodiment of the present invention, and FIG. 9B is a top view of a stator according to the sixth embodiment of the present invention.

FIG. 10 is a diagram showing a winding configuration according to a sixth embodiment of the present invention.

FIG. 11 is a diagram showing a winding configuration according to a seventh embodiment of the present invention.

FIG. 12 is a front sectional view of a main part of a conventional example of a permanent magnet type synchronous motor.

FIG. 13 is a diagram showing a winding form in a conventional example.

14 (a) is a front sectional view of a main part of a conventional permanent magnet type linear motor, and FIG. 14 (b) is a top view of a stator.

FIG. 15 is a diagram showing a winding form in a conventional example.

[Explanation of symbols]

 Reference Signs List 1 armature core 2 teeth 3 slot wound coil 4 back yoke 5 air core coil 6 permanent magnet (rotor) 10 mover 11 mover yoke 12 permanent magnet 13 stator 14 stator yoke (core) 15 back yoke 16 air core coil 17 Teeth 18 Slot wound coil 19 Air-core coil 20 Rotor core 22, 25 Lower coil side 23, 26 Upper coil side 27 Armature core 28 Field permanent magnet 29 Slot 30 Mover 31 Mover yoke 32 Permanent magnet 33 Stator 34 Fixed Child yoke 35 air core coil

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yukio Tsutsui 2-1, Kurosaki Shiroishi, Yawata Nishi-ku, Kitakyushu-shi, Fukuoka Prefecture Inside Yaskawa Electric Corporation

Claims (6)

[Claims] 1. A mover in which a stator having a coil wound around an armature core and a multiple of two field permanent magnets on the outer peripheral surface of a yoke are fixed such that adjacent magnetic poles are magnetized to different polarities. In the permanent magnet type motor having the electromagnetic configuration, the armature core of the stator has a portion formed with teeth and a slot, and a portion formed only with the back yoke having no teeth in the moving direction of the mover. The permanent magnet type, wherein the coils formed by the armature windings of the stator are alternately arranged, and the coils are formed of a coil wound around the teeth and an air-core coil arranged on the back yoke. motor. 2. The permanent magnet type motor according to claim 1, wherein the circumferential width of the air-core coil on the back yoke is increased to 1.2 to 1.6 times the pole pitch. 3. The permanent magnet motor according to claim 1, wherein the radial width of the air-core coil on the back yoke is set to be 0.2 to 0.6 times the pole pitch. 4. The apparatus according to claim 1, wherein the teeth are arranged such that the center spacing of the teeth is changed so that an electrical angle of 90 degrees and an electrical angle of 30 degrees alternate. A permanent magnet type motor as described. 5. An electromagnetic configuration of a stator provided with an armature winding and a mover having a plurality of field permanent magnets fixed on a mover yoke such that adjacent magnetic poles are magnetized to different polarities. , The armature winding is composed of an integral number of coils of m, where m is the number of phases, a part of the integral number of coils of m phases is provided on the stator, and the remaining coils are provided. Is a permanent magnet linear motor characterized by being provided at a place other than the stator. 6. The permanent magnet linear motor according to claim 5, wherein a coil provided in a place other than the stator is used as a heater.