JP2001008434A - Switched reluctance motor and load transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an SR linear motor which can make thrust ripples smaller by hardly lowering its average thrust by changing the shapes of poles on the primary side, on which field coils are wound and which usually becomes a stator. SOLUTION: An SR linear motor 11, which is driven with a three-phase alternating current, has two or more sets of three-pole units having primary-side poles 13a-13f wound with field coils 14. The poles 13b, 13d, and 13f, having rectangular cross sections and the poles 13a, 13c, and 13e having tapered front ends, are arranged alternately. Accordingly, the poles 13a-13f are formed, in such a way that the distances L1 and L2 between the center lines O1 and O3 of the facing sides of the front end faces of the poles 13a, 13b, 13d, and 13e which are positioned on both sides of the central pole 13c of the continuous five poles 13a-13e and the center lines O2 and O4 of the poles 13b and 13e positioned on the downstream side in the moving direction of a moving piece become different from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switched reluctance motor (hereinafter referred to as an SR motor) in which two or more sets of three poles are present as primary poles on which an exciting coil is wound. ) And a load transfer device including a switched reluctance linear motor (hereinafter, referred to as an SR linear motor) as a driving source.

[0002]

2. Description of the Related Art Conventionally, various linear motors corresponding to rotary machines have been known, and some of them have been implemented. Among the linear motors, a linear DC motor, a linear pulse motor, a linear induction motor and the like have been put to practical use. Among them, a linear induction motor is used for a relatively large device such as a pallet transfer device.

In a linear induction motor, end effec
Since there is a phenomenon called t), there is a problem that the thrust is reduced particularly in a high-speed region. As a result, there is a problem that the device becomes large in order to obtain a large thrust. In addition, the linear pulse motor has features such as open-loop control because the movable part moves in synchronization with the input pulse signal, and the displacement error does not accumulate. Magnetic poles and teeth (projections) provided at the pitch
It is necessary to narrow the distance between the two (to about 1 to 2 mm), and in a device such as a load transfer device that requires a large moving distance,
There is a problem that it takes time to process magnetic poles and teeth and wind a coil.

[0004]

SUMMARY OF THE INVENTION The applicant of the present application has studied an SR linear motor which has hardly been studied for practical use in the past, and developed an SR linear motor in which a conventional rotary SR motor is directly developed on a plane. Created. Then, the generated thrust was measured by applying a drive circuit system applied to a conventional rotary SR motor, for example, a one-phase excitation drive (unipolar circuit) and a two-phase excitation drive (bipolar circuit). As a result, it has been found that an average thrust several times higher than that of the conventional linear induction motor is obtained, and that the average thrust is larger in the one-phase excitation drive.

Further, the applicant of the present invention has proposed that an SR linear motor which uses a self-inductance and a mutual inductance as an operating principle and uses a bipolar sine-wave drive as a driving method is an SR linear motor in which a rotary SR motor is developed as it is on a plane. It was found that the thrust increased at the same current density as the motor, and there was no point where the generated thrust became zero.

[0006] Since the SR linear motor has a large thrust ripple in principle, there is a problem that it is difficult to smoothly drive and improve the positioning accuracy. The SR motor also has a similar problem. However, in the case of the SR motor, the torque corresponds to the thrust of the SR linear motor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to provide teeth (poles) on a primary side, usually a stator side, on which an exciting coil is wound. It is an object of the present invention to provide an SR motor capable of reducing torque or thrust ripple without substantially reducing average thrust by changing the shape. Another object of the present invention is to provide a load transfer device provided with an SR linear motor having a small thrust ripple as a driving source.

[0008]

In order to achieve the first object, according to the first aspect of the present invention, two sets of three poles are provided as primary poles on which an exciting coil is wound. The above-mentioned SR motor driven by a three-phase AC, wherein the poles have different shapes every other one and
Between the center position of the opposing sides of the tip surface of each of the two poles located on both sides of the center pole of the poles and the center line of the pole located downstream from the center position in the moving direction of the mover. The distances were different.

According to the second aspect of the present invention, in the first aspect of the present invention, the shape of the secondary tooth is such that the surfaces located on both sides in the direction of movement of the tooth are more perpendicular to the surface perpendicular to the tooth tip surface. It is formed in a shape bulging outward.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the two types of poles having different shapes have one pole formed in a rectangular cross section and the other pole formed in a rectangular cross section. The tip of one pole is formed in a chamfered shape.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the SR motor is a linear motor. In the invention according to claim 5,
The invention according to claim 4, wherein the primary side pole is 3
A plurality of units each having n pairs of poles (n is a natural number of 2 or more) are provided, and the interval between adjacent units is set to be the interval between adjacent poles equal to 2 times the pitch of the poles in the unit.
Assuming that there is a virtual pole and a coil between the units in the order of three phases, the arrangement of adjacent poles is arranged so as to be double or triple, and adjacent poles of adjacent units are different. The coil phases were set to repeat in the same order.

In order to achieve the second object, the invention according to claim 6 includes one fixed portion, and a plurality of movable portions that can be sequentially fed horizontally to the fixed portion. The SR linear motor according to claim 4 or 5 is built in at least one of the fixed part and the movable part as a drive part for a moving operation of the movable part.

The SR motor according to the present invention is driven by three-phase alternating current. For example, when a three-phase sine wave current is supplied to a coil wound on a primary pole, magnetic flux is generated through each pole and secondary teeth corresponding to each pole. The torque or thrust due to the magnetic flux changes depending on the positional relationship between the primary side and the secondary side, and the center of the two teeth on the secondary side and the center position of the opposing sides of the tip surfaces of the two poles on the primary side When they match, the torque or thrust is minimized. The center position of the opposing sides of the tip surface of each of the two poles located on both sides of the center pole of the five consecutive poles, and the center of the pole located downstream from the center position in the moving direction of the mover Since the distance from the line is different, a difference occurs between a position where current of the same phase is flowing and a position where the thrust corresponding to a different pole is minimum, and thrust ripple is reduced.

According to a second aspect of the present invention, in the first aspect of the present invention, the leakage of magnetic flux from the primary pole to the secondary teeth is reduced, and the minimum level of thrust is improved.
Torque ripple (thrust ripple in a linear motor) is further reduced.

According to the third aspect of the present invention, since the tip of one of the poles is chamfered, the operation of winding the coil around the pole becomes easier as compared with a configuration in which the width of the tip of the pole is widened. .

According to the fourth aspect of the present invention, the SR linear motor has the functions corresponding to the first to third aspects. According to the invention described in claim 5, in the invention described in claim 4, thrust ripple of each unit having n units of one set of three poles is reduced, and the thrust ripple between each unit is reduced. Since the arrangement is shifted from each other, the average thrust does not decrease and the thrust ripple decreases as a whole of the SR linear motor.

According to a sixth aspect of the present invention, there is provided a load transfer device according to the fourth or fifth aspect, wherein at least one of the fixed part and the movable part is used as a driving part for moving the movable part in and out. , The thrust ripple is reduced with little decrease in average thrust.

[0018]

(First Embodiment) A first embodiment of the present invention will be described below with reference to FIGS.

First, the structure of a fork device as a load transfer device will be described. As shown in FIGS. 3 and 4, the fork device 1 includes a fixed fork 2 as a fixed portion, and a middle fork 3 and an upper fork 4 as a plurality of movable portions that can be sequentially fed to the fixed fork 2. .

As shown in FIG. 3, a pair of rails 5 extending in the longitudinal direction are fixed to the bottom surface of the middle fork 3, and each rail 5 is fixed to a central portion in the longitudinal direction of the fixed fork 2. 6 movably supported along the longitudinal direction of the fixed fork 2. A pair of support rollers 7 is provided at each end of the fixed fork 2.
(Illustrated in FIG. 4). The middle fork 3 is movable in the longitudinal direction with respect to the fixed fork 2 while being supported by the linear guide block 6 and the support roller 7.

Similarly, a pair of rails 8 are fixed to the bottom surface of the upper fork 4, and the middle fork 3 is provided with a linear guide block 9 and a support roller 10.
The upper fork 4 is movable in the longitudinal direction with respect to the middle fork 3 while being supported by the linear guide block 9 and the support roller 10.

At the center of the fixed fork 2, a stator 12 as a primary side of an SR linear motor 11 as a drive source is fixed. As shown in FIG. 1, the stator 12 has 3n poles (n = 2 in this embodiment), and each of the poles 13a to 13a.
13f are formed at an equal pitch. That is, there are two sets of three poles. The coils 14 are all wound around the poles 13a to 13f in a concentrated manner in the same direction so that the self-inductance and the mutual inductance are used together as the operating principle of the SR linear motor 11. Coil 14
Are indicated by reference numerals in FIGS. 1, 5 and 6. FIG.

Each coil 14 is configured to have three phases, and the coils 14 corresponding to the poles 13a and 13d have a u phase,
The coil 14 corresponding to the poles 13b and 13e has a v-phase, pole 1
The w-phase current is supplied to the coil 14 corresponding to 3c and 13f via the three-phase inverter 15, respectively. The inverter 15 is controlled via a control device 16, and the control device 16 controls the inverter 15 so as to drive the SR linear motor 11 into a sine wave.

A mover 17 as a secondary side of the SR linear motor 11 is fixed by bolts 18 in a groove 3a formed on the bottom surface of the middle fork 3 so as to extend over substantially the entire length in the longitudinal direction. . Protrusions 17a as teeth are formed on the mover 17 at an equal pitch, and the protrusions 17a are arranged so as to be able to face the poles 13a to 13f. When a current is supplied to each coil 14, the middle fork 3 is moved in the longitudinal direction.

The ratio of the number of the poles 13a to 13f of the stator 12 to the number of the protrusions 17a of the movable element 17 corresponding to the stator 12 is set to 3: 4. Poles 13a-13f
The projection 17a has substantially the same width.

Each of the poles 13a to 13f has a shape different from that of every other pole, and is formed on the opposite side of the tip end face of each of two poles located on both sides of the center pole of five consecutive poles. The distance between the center position and the center line of the pole located on the downstream side in the moving direction of the mover from the center position is different. In this embodiment, one pole 13b, 13d, 13f of two kinds of poles having different shapes is formed in a rectangular cross section, and the other poles 13a, 13c, 13e are formed in one pole, that is, a rectangular cross section. The pole tip is formed in a chamfered shape. Therefore, when looking at five consecutive poles, for example, regarding the poles 13a to 13e, the two poles 13a, 1 located on the left side in FIG.
The distance L1 between the center position O1 of the opposite side of the distal end face of the tip 3b and the center line O2 of the pole 13b located downstream of the center position in the moving direction of the mover is located on the right side in FIG. A distance L2 between the center position O3 of the opposing sides of the tip surfaces of the two poles 13d and 13e and the center line O4 of the pole 13e located on the downstream side in the moving direction of the mover from the center position.
And different.

The protrusion 17a of the mover 17 has a surface located on both sides in the moving direction of the protrusion 17a.
7a is formed in a shape swelling outward from a plane perpendicular to the front end face of 7a. In this embodiment, the projection 17a is formed in a tapered shape that becomes wider toward the base end.

One side of the fixed fork 2 in the width direction (FIG. 3)
A rack 19 is fixed in a groove formed on the upper surface of the right side of FIG. A rack 20 is fixed in a groove formed on the lower surface of the upper fork 4. On the middle fork 3, a rotating shaft 23 having pinions 21 and 22 respectively engaged with the racks 19 and 20 fixed to both ends is rotatably supported via a bearing 24. Pinions 21, 22
Are formed the same. Therefore, when the middle fork 3 moves, the racks 19 and 20 and the pinions 21 and 22 are moved.
, The upper fork 4 is moved by the same distance with respect to the middle fork 3.

At the center of the side surface (right side in FIG. 3) of the fixed fork 2, there is provided an origin sensor S1 for detecting that the movable element 17 is at the origin position, that is, that the middle and upper forks 3, 4 are at the reference position. I have. The origin sensor S1 detects a detected member (dog) 25 fixed to the bottom surface of the middle fork 3, and detects that the mover 17 is at the origin position. In this embodiment, a limit switch is used as the origin sensor S1.

On the bottom surface of the middle fork 3, a linear scale 26 is provided on one side (left side in FIG. 3) in the width direction along the longitudinal direction of the mover 17 so as to extend over the entire length of the mover 17. ing. The linear scale 26 has a configuration having a magnetized portion that is magnetized alternately with N poles and S poles at a predetermined pitch. At the center of the side surface (left side in FIG. 3) of the fixed fork 2, a magnetic sensor 27 for sequentially detecting each magnetized portion of the linear scale 26 is provided.

Further, the fixed fork 2 is provided with an abnormality detection sensor 28 for detecting an abnormality in which the middle fork 3 extends excessively beyond a predetermined extending position. The abnormality detection sensors 28 are provided at both ends in the longitudinal direction of the fixed fork 2, and are configured to detect a dog 29 fixed to the longitudinal center of the lower surface of the middle fork 3.

The output signals of the sensors S1, 27, and 28 are input to the control device 16, and the control device 16 outputs an acceleration / deceleration command and a stop command for the SR linear motor 11 based on those signals. Has become. Control device 1
6 is a magnetic sensor 27 according to the movement of the linear scale 26.
Is counted, and the moving distance of the mover 17 from the origin position is calculated.

Next, the operation of the fork device 1 configured as described above will be described. The fork device 1 is mounted on, for example, a stacker crane of an automatic warehouse. The control device 16 synchronously drives the SR linear motor 11 by sine wave driving from the state where it is confirmed that the mover 17 is at the origin position based on the output signal of the sensor S1. When the mover 17 is at the origin position, as shown in FIG. 1, the predetermined protrusion 17a is arranged in a state of facing the u-phase poles 13a and 13d. The control device 16 determines, based on the output signal of the sensor S1,
The position of the middle fork 3 is recognized, the deceleration position and the stop position are confirmed, a deceleration command is output at a predetermined deceleration position, and a stop command is output at the stop position.

From the state where the middle fork 3 and the upper fork 4 are arranged at the reference position, that is, the state where the mover 17 is arranged at the origin position, the coil 14 of the stator 12 of the SR linear motor 11 is sequentially driven by a sine wave. When a current is supplied, the amount of magnetic flux passing through the poles 13a to 13f and the corresponding protrusion 17a sequentially changes. Then, the suction force acting on the protrusion 17a of the mover 17 sequentially changes, and the middle fork 3 to which the mover 17 is fixed moves in a predetermined direction. In FIG. 1, the magnetic flux passing through the projection 17a located on the left side of the poles 13a to 13f and the pole corresponding to the projection 17a gives a thrust to the mover 17 in the right direction, and the projection located on the right side. The magnetic flux passing through the pole corresponding to the projection 17a and the projection 17a gives the mover 17 a thrust to the left. Therefore, if the poles 13a to 13f are sequentially excited so that the amount of magnetic flux that gives a thrust to the left increases, the mover 17 moves to the left, and the amount of magnetic flux that gives a thrust to the right increases. If the poles 13a to 13f are sequentially excited as described above,
7 moves rightward.

The rotation shaft 23 supported by the middle fork 3 moves integrally with the movement of the middle fork 3, and the pinion 21 meshing with the rack 19 rotates integrally with the rotation shaft 23. Then, the pinion 22 fixed to the rotating shaft 23 rotates integrally, and the rack 20 meshing with the pinion 22 is moved by the same amount as the movement amount of the middle fork 3 with respect to the fixed fork 2. Therefore, the upper fork 4 to which the rack 20 is fixed is moved relative to the middle fork 3 by the same amount, and the upper fork 4
Is moved twice as much as the middle fork 3.

Next, the operation when the shapes of the poles 13a to 13f are changed every other pole will be described. FIG. 5 is a partial schematic diagram in the case where the shape of the protrusion 17a of the mover is a general rectangular shape, and the shapes of the poles 13a to 13f of the stator 12 are changed every other. At a certain point in time when the current is supplied to the coil 14, as shown in FIG. 5, the magnetic flux mainly passes through the u-phase and the v-phase and the corresponding projections 17a. The amount of magnetic flux is substantially proportional to the amount of current supplied to the coil 14, and the amount of current varies sinusoidally. Therefore, the poles 13a and 13d to which the u-phase current is supplied and the poles 1 to which the v-phase current is supplied
The amount of magnetic flux with 3b and 13e also changes similarly.

The mover 17 having two poles 13a and 13b
Is minimized when the center position O1 of the opposing sides of the tip surfaces of the two poles 13a and 13b coincides with the center position O of the two protrusions 17a corresponding to the poles 13a and 13b. If the shapes of all the poles 13a to 13f are the same, the change in thrust on the mover 17 by the poles 13a and 13b is the same as the change in thrust on the mover 17 by the poles 13d and 13e. Therefore, the thrust acting on the mover 17 is the sum of the two.

However, the center position O1 of the opposing sides of the tip surfaces of the two poles 13a and 13b and the pole located downstream of the center position O1 in the moving direction of the mover 17 (the right side in FIG. 5). The distance L1 from the center line O2 of 13b is the center position O3 of the opposing sides of the tip surfaces of the two poles 13d and 13e.
And the center line O of the pole 13e located downstream of the center position O3 in the moving direction of the mover 17 (the right side in FIG. 5).
4 is different from L2. Therefore, the poles 13a, 13b
Is different from the position where the thrust on the mover 17 by the poles 13d and 13e is minimized. Similarly, the same applies to the state where the magnetic flux mainly passes through the v-phase and w-phase poles 13b, 13c, poles 13e, 13f and the corresponding projection 17a. Then, as shown in FIG. 2, the thrust F1 change due to the set of poles 13a to 13c and the thrust F2 change due to the set of poles 13d to 13f are shifted in the direction of the position of the mover 17,
The maximum value of the change in the total thrust F obtained by adding the two becomes small, and the minimum value becomes large. As a result, the thrust ripple is reduced without reducing the average thrust.

Next, the operation in the case where the shape of the projection 17a is formed in a tapered shape that becomes wider toward the base end will be described. FIG. 6 is a partial schematic diagram in the case where the shape of the protrusion 17a is changed and the shapes of the poles 13a to 13f of the stator 12 are formed in a general rectangular shape. In FIG. 6, for example, when the current supplied to the u-phase becomes weak and the current supplied to the v-phase becomes strong, the corresponding protrusion 1 from the pole 13 b of the v-phase.
The amount of magnetic flux going to 7a increases. At this time, the pole 13b
The shorter the distance until the magnetic flux coming out of the front end surface reaches the projection 17a, the greater the thrust. Since the width MTW of the tip surface of the projection 17a has an optimum value corresponding to the width STW of the poles 13a to 13f, the thrust decreases when the entire width of the projection 17a is increased. However, the width MTW of the tip end surface is not changed, and the surfaces located on both sides in the moving direction of the protrusion 17a are formed to have a shape bulging outward from a surface perpendicular to the front end surface of the protrusion 17a. The distance until the magnetic flux coming out of the distal end surface reaches the protrusion 17a is shortened, and the minimum value of the thrust increases. As a result, thrust ripple is reduced.

Each of the poles 13a to 13f is changed every other pole, and the protrusions 17a are formed in a tapered shape as shown in FIG. 1, and the poles 13a to 13f are all rectangular and the protrusions 17a are formed in a tapered shape. The case shown in FIG.
FIG. 7 shows the results of comparison of the average thrust using FEM (finite element method) for the cases where a to 13f and the protrusion 17a are rectangular.

In FIG. 7, a white circle shows a case where the shape is not changed, a black circle shows a case where the protruding portion 17a is formed in a tapered shape, and a white circle shows a tapered shape of every other end of the poles 13a to 13f. And a case where the projection 17a is formed in a tapered shape. Average thrust is 223 without shape change
When the ripple amount is 66.7% at 2N and the protrusion 17a is formed in a tapered shape, the average thrust is 2292N and the ripple amount is 6
When the shapes of both the pole and the projection 17a were changed to 3.8%, the average thrust was 2202N and the ripple amount was 43.9%.

As compared with the case without the shape change, the protrusion 17
When a was formed in a tapered shape, both the value of the thrust change at the valley and the value at the peak were large, and the rate of increase of the valley was larger. That is, the average value of the thrust was improved and the thrust ripple was reduced. When the shapes of both the poles and the protrusions 17a were changed, the value at the valley of the thrust change increased and the value at the peak decreased. Then, the average thrust was slightly reduced (almost 1%), but the thrust ripple was significantly reduced.

This embodiment has the following effects. (1) The shape of each of the poles 13a to 13f is different from every other, and the centers of the opposing sides of the tip surfaces of the two poles located on both sides of the center pole of five consecutive poles The distance between the center position and the center line of the pole located on the downstream side in the moving direction of the mover 17 from the center position is different. Therefore, a change in thrust by each unit of the three poles causes a shift in the position direction of the mover 17, so that the total thrust F obtained by adding the two can reduce the thrust ripple without substantially reducing the average thrust. .

(2) The two types of poles having different shapes are such that one pole 13b, 13d, 13f is formed in a rectangular cross section,
The other poles 13a, 13c, 13e are formed in a shape in which the tip of one pole is chamfered. Therefore, the operation of housing the coil 14 in the poles 13a to 13f becomes easier as compared with a configuration in which the width of the pole tip surface is increased.

(3) The shape of the protrusion 17a of the mover 17 is such that the surfaces located on both sides in the moving direction of the protrusion 17a
Since it is formed in a shape bulging outward from a surface perpendicular to the tip end surface of 7a, the thrust ripple can be reduced without reducing the average thrust.

(4) The number of the poles 13 a to 13 f of the stator 12 and the protrusion 1 of the movable element 17 corresponding to the stator 12
The ratio with respect to the number 7a is set to 3: 4, the number of poles of the stator 12 is 3n (n is a natural number), and the coils 14 of each pole are all wound in the same direction. Therefore, a configuration using both self-inductance and mutual inductance as an operating principle can be easily formed, and the poles 13a to 13f and the protrusion 17
The attraction force due to the magnetism acting between the movable element 17a and the magnetic field a efficiently acts as the thrust of the mover 17.

(5) Poles 13a to 13f and projection 17a
Are formed to have substantially the same width, so that the poles 13a to 13f
And the ratio of the number of the protrusions 17a to the number of the protrusions 17a is set to 3: 4. Acts efficiently as

(6) Since the driving method is bipolar sine wave driving, a general-purpose inverter can be used as the driving circuit, and the manufacturing cost is higher than that of the unipolar one-phase excitation driving which requires a dedicated driving circuit. Can be reduced.

(7) Since the SR linear motor 11 is used as a driving unit for the moving operation of the movable unit of the fork device 1, an induction linear motor of the same size or a rotary SR
The thrust is increased at the same current density as compared to an SR linear motor in which the motor is developed in a plane. Therefore, if the size of the linear motor is the same, a heavy load can be transferred, and if the thrust required for transferring the load is the same, the linear motor can be downsized.

(Second Embodiment) Next, a second embodiment will be described with reference to FIG. In this embodiment, in order to increase the thrust of the SR linear motor 11, the number of units of one set of three poles is increased (three times in this embodiment) as compared with the above embodiment, and the stator as a primary side is different. 12 poles are 3
This embodiment is greatly different from the above-described embodiment in that it is constituted by a plurality of units 30 each having two sets of pole units. The same portions are denoted by the same reference numerals and description thereof will be omitted.

Each unit 30 is formed in the same configuration as one stator 12 of the above embodiment. Each unit 3
0 is set so that the interval (pitch) Pn between the adjacent poles 13f and 13a is twice the pitch P of the poles in the unit 30 and the interval between adjacent poles 13f of the adjacent unit 30 is set to 0. And the shape of the pole 13a is different. That is, all three units 30 are arranged in the same direction. Moreover, each pole 13a-13
The order of the three phases in which the coil 14 of the f
Assuming that a virtual pole and the coil 14 exist between them, the phases of the coil 14 of all the poles 13a to 13f are set to be repeated in the same order. Which poles are u phase, v phase, w
Which of the phases is determined when each unit 30 is assembled at a predetermined position and the wiring of the coil 14 is finally connected, so that the structure of each unit 30 is the same.

In the configuration of this embodiment, the thrust ripple is reduced for each of the units 30 with little effect on the average thrust by the same operation as in the above embodiment. When the units 30 are simply arranged such that the interval Pn between the adjacent poles 13f and 13a is the same as the pitch P of the poles in the unit 30, three units 30 each serving as the thrust of the entire SR linear motor 11 are provided. Is obtained, the maximum value and the minimum value of each unit 30 overlap each other. However, in the configuration of this embodiment, the poles 13a to 13a corresponding to the u-phase, v-phase, and w-phase are provided for each unit 30.
Since the position of f is different, the peak and the valley of the thrust of each unit 30 are shifted, and the thrust ripple is reduced.

The distance Pn between the adjacent poles 13f and 13a between the adjacent units 30 is equal to that of the unit 3.
In the case where the pitch is twice the pitch P of the poles within 0 (embodiment), the case where 18 poles are arranged at the same pitch P
When two consecutive stators are used (reference), the end of the unit 30 is shortened and the adjacent poles 1 between the units 30 are removed.
In the case where the pitch P between the electrode 3f and the pole 13a is the same as the pitch P of the pole in the unit 30 and the interval between the units 30 is smaller than one pitch of the pole (comparative example), the FE
The average thrust and the thrust ripple were compared for the model using 300 kg using M (finite element method). As a result, in the embodiment, the average thrust is 6200 N and the thrust pull is 45.0.
%, The standard thrust is 6180N and thrust pull is 4
In the comparative example, the average thrust was 6180 N and the thrust pull was 48.3%. That is, even if the stator as the primary side is divided, the thrust characteristics hardly change, but it is confirmed that the thrust ripple is reduced in the embodiment.

This embodiment has the following effects in addition to the effects similar to (2) to (7) of the first embodiment. (8) In order to increase the thrust of the SR linear motor 11, the poles 13a to 13f are lengthened to increase the number of turns of the coil 14 of each pole, that is, the thickness of the SR linear motor 11 is increased, or Need to increase the number of poles. If the thickness of the SR linear motor 11 is restricted, the number of poles will be increased. In this case, if all the poles are provided in one unit, the overall length of the unit becomes long, and machining and assembly of the stator 12 becomes difficult.
However, in this embodiment, since the short units 30 are combined, processing, assembling, and accuracy control are facilitated.

(9) A primary-side pole is constituted by a plurality of units 30 each including n sets of three poles (n is a natural number of 2 or more), and the interval between adjacent units 30 is set to be adjacent to the primary side. Arrangement is made such that the interval Pn between the matching poles 13f and 13a is twice as large as the pitch P of the poles in the unit 30 and the shapes of the adjacent poles of the adjacent units 30 are different. Assuming that a virtual pole and coil 14 exist between them, the phases of the coils of all poles were set to be repeated in the same order. Therefore, the thrust ripple can be reduced without lowering the average thrust.

(10) When the SR linear motors 11 of various thrusts are manufactured in a series, for example, when the number of units of a set of three poles is two, four, or six,
One mold can be used in common, and the production cost can be reduced as compared to preparing individual molds.

The embodiment is not limited to the above, and may be embodied as follows, for example. The shapes of the poles 13a, 13c and 13e which are not rectangular in cross section are not limited to the tapered shape, and the end faces of two poles located on both sides of the center pole of five consecutive poles are opposed to each other. Any shape may be used as long as the distance between the center position of the side and the center line of the pole located downstream of the center position in the moving direction of the mover is different. For example, as shown in FIG. 9A, the tip of the pole 13c is formed in a narrow rectangular shape, or as shown in FIG. 9B, the tip of the pole 13c is formed in a tapered shape that becomes wider toward the tip. May be. If there is room in the width of the poles 13a to 13f, the shape of the pole whose shape is to be changed may be rectangular and narrow.

As shown in FIG. 9 (c), without changing the outer shape of the pole 13c, holes 31 extending in the direction perpendicular to the moving direction of the mover (perpendicular to the plane of FIG. 9) are formed on both sides of the tip. It may be formed. By forming the hole 31 so that the thickness of the pole located outside the hole 31 is reduced, the portion outside the hole 31 is immediately magnetically saturated. As a result, the operation is the same as that when the width of the tip end surface of the pole 13c is reduced.

The protrusion 17a of the mover 17 may have a rectangular cross section, and the poles 13a to 13f of the stator 12 may be changed every other pole. The shape of the protrusion 17a of the mover 17 may be such that the surfaces located on both sides in the movement direction of the protrusion 17a are formed so as to bulge outward from a surface perpendicular to the tip end surface of the protrusion 17a.
It is not limited to a tapered shape. However, the processing is simplified in the case of forming in a tapered shape.

The number of poles of the stator 12 is not limited to six,
Nine or more multiples of three may be used. That is, the stator 12
May be 3n (n is a natural number of 2 or more).
In this case, a general-purpose three-phase inverter can be easily used as the drive circuit.

The poles having different shapes may be odd-numbered poles instead of odd-numbered poles. If the total number of poles is an even number, the direction is 1 even if the odd number is a different shape.
If the angle is changed by 80 degrees, the even-numbered shape will be different. However, if the total number of poles is odd, even if the direction is changed by 180 degrees, the even-numbered shape will not be different.

The interval Pn between the adjacent poles 13f and 13a between the adjacent units 30 may be set to three pitches of the poles. Also in this case, the thrust ripple can be reduced. In the second embodiment, three sets of three poles may be used instead of two sets of three poles as the unit 30. In this case, the same effect as in the case of two sets can be obtained.

The present invention is not limited to the SR linear motor 11, but may be applied to a rotary SR motor. For example, as shown in FIG. 10, six poles 34a to 34f are provided at equal intervals inside a cylindrical stator 33 of the SR motor 32, and the tip of every other pole 34a, 34c, 34e is tapered. Tapered,
The other poles 34b, 34d, 34f are formed in a rectangular cross section. The teeth 35a of the mover (rotor) 35 are formed in a tapered shape. Also in this case, the torque ripple is reduced for the same reason as in the case of the SR linear motor 11.

The widths of the poles 13a to 13f and the protrusions 17a do not necessarily have to be substantially the same.
The pitch of each of the projections 13f and the projections 17a may be the same and may have different widths.

A plurality of small teeth may be formed at the poles 13a to 13f and the tip of the projection 17a. The fork device 1 is not limited to the three-stage type, but may be a two-stage type or a four-stage type.

The SR linear motor 11 may be disposed between all the movable forks, and the driving mechanism of the movable fork by the pinion and the rack may be eliminated. In this case, dust generation due to the engagement between the rack and the pinion is eliminated, and the device is suitable for use in a clean room or the like.

The present invention may be applied to a fork device 1 in which the middle fork 3 and the upper fork 4 can reciprocate to one side without reciprocating from the origin position to the left and right sides with respect to the fixed fork 2. In this case, the stator 12 is arranged not to the center of the fixed fork 2 but to one side.

Instead of mounting the fork device 1 on a stacker crane, it may be mounted on a self-propelled carrier.
Further, the fork device 1 may be used as a stationary transfer device.

The SR linear motor 11 is not limited to the fork device 1 and may be applied as a drive source for machine tools, industrial machines and other moving mechanisms. The primary side of the SR linear motor 11 may be a mover and the secondary side may be a stator. In this configuration,
By disposing the stator along the rail that guides the moving body and attaching the mover to the moving body, the moving body can be moved for a long distance by the SR linear motor.

The technical ideas (inventions) other than those described in the claims which can be grasped from the embodiment will be described below together with their effects. (1) In the invention described in claim 4 or claim 5,
The driving method is sine wave driving. In this case, a general-purpose inverter can be used as the drive circuit, and the manufacturing cost can be reduced.

(2) The load transfer device according to claim 6 is
The stator of the SR linear motor is provided on the fixed part, the mover is provided on the movable part facing the fixed part, and the other movable parts are moved in and out by a drive mechanism using a combination of a pinion and a rack. In this case, routing of the wiring to the load transfer device is simplified.

[0072]

As described in detail above, claims 1 to 5 are provided.
According to the invention described in the above, the simple configuration of changing the shape of the teeth (poles) on the primary side on which the excitation coil is wound, usually on the side serving as the stator, and without substantially reducing the average thrust, Alternatively, thrust ripple can be reduced.

According to the second aspect of the present invention, the leakage of magnetic flux from the primary side pole to the secondary side teeth is reduced, the minimum level of thrust is improved, and the torque ripple (thrust ripple in a linear motor) is further improved. Reduced.

According to the third aspect of the present invention, since the tip of one of the poles is chamfered, the operation of accommodating the coil in the pole becomes easier as compared with a configuration in which the width of the tip of the pole is widened. . According to the fourth aspect of the invention, the SR linear motor has the effects corresponding to the first to third aspects.

According to the fifth aspect of the present invention, when manufacturing an SR linear motor having a large thrust, processing of the pole on the primary side,
It is easy to assemble, and the thrust ripple can be reduced without reducing the average thrust.

According to the invention, heavy loads can be transferred if the linear motors have the same size, and the linear motor can be downsized if the thrust required for transferring the loads is the same. Moreover, since the thrust ripple is small, it is possible to smoothly drive and improve the positioning accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic side view of an SR linear motor according to a first embodiment.

FIG. 2 is a graph showing the relationship between the position of the mover and the thrust.

FIG. 3 is a sectional view of a fork device.

FIG. 4 is a schematic perspective view of a fork device.

FIG. 5 is a schematic diagram for explaining the operation when the stator side has a different shape.

FIG. 6 is a schematic diagram for explaining the operation when the teeth of the mover have different shapes.

FIG. 7 is a graph showing the relationship between the position of the mover and the thrust.

8A is a schematic side view of an SR linear motor according to a second embodiment, and FIG. 8B is a partially enlarged view thereof.

FIG. 9 is a schematic view showing the shape of a pole according to another embodiment.

FIG. 10 is a schematic diagram of a rotary SR motor according to another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fork apparatus as a load transfer apparatus, 2 ... Fixed fork as a fixed part, 3 ... Middle fork as a movable part, 4 ... Upper fork, 11 ... SR linear motor as SR motor, 12 ... As primary side Stator,
13a-13f, 34a-34f ... poles, 14 ... coils,
17: mover as secondary side, 17a: protrusion as tooth, 30: unit, 32: SR motor, P: pitch.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Taiji Otachi 2-1-1 Toyota-cho, Kariya-shi, Aichi F-term in Toyota Industries Corporation (reference) 3F333 AA02 AB13 AE03 BA14 FA32 5H619 AA01 AA05 BB01 BB24 PP01 PP02 PP05 5H641 BB06 BB19 GG02 GG04 GG08 GG11 GG12 GG24 GG26 GG28 HH08 HH10 HH14 JA04 JA09

Claims (6)

[Claims] 1. A switched reluctance motor driven by three-phase alternating current, wherein two or more sets of three poles are present as primary poles on which an exciting coil is wound, wherein the shape of the poles is And the center of opposing sides of the tip face of each of the two poles located on both sides of the center pole of the five consecutive poles, and A switched reluctance motor formed to have a different distance from a center line of a pole located on the downstream side in the moving direction. 2. The secondary tooth shape according to claim 1, wherein the surfaces located on both sides in the direction of movement of the tooth are formed so as to bulge outward from a surface perpendicular to the tooth tip surface. Switched reluctance motor. 3. The two types of poles having different shapes, one of the poles is formed in a rectangular cross section, and the other pole is formed in a shape in which the tip of one of the poles is chamfered. A switched reluctance motor according to claim 2. 4. The switched reluctance motor according to claim 1, wherein the switched reluctance motor is a linear motor. 5. A method according to claim 1, wherein the primary side pole is a unit of three poles and the unit is n.
Each unit (n is a natural number of 2 or more) is constituted by a plurality of units, and the interval between adjacent units is set so that the interval between adjacent poles is twice or three times the pitch of the poles in the unit. The arrangement of adjacent poles of adjacent units is different, and the order of the three phases is repeated in the same order, assuming that there are virtual poles and coils between the units. The switched reluctance motor according to claim 4, wherein the motor is set to be driven. 6. A fixed portion and a plurality of movable portions which can be sequentially and horizontally extended with respect to the fixed portion, and at least one of the fixed portion and the movable portion has a drive for moving the movable portion in and out. A load transfer device incorporating the switched reluctance linear motor according to claim 4 or 5 as a part.