JPH0880027A - Linear motor - Google Patents

Abstract

PURPOSE: To prevent an adverse effect on field flux by a motor current component by dividing magnetic paths from a plurality of magnetic poles on the secondary side into blocks, reducing reluctance from each magnetic pole to each adjacent magnetic pole and increasing reluctance in the magnetic poles as viewing from both ends of each magnetic pole in the direction of the driving of a linear motor. CONSTITUTION: The primary side 161 is manufactured by laminating rolled magnetic steel sheets, and three-phase AC windings are wound in each slot. Magnetic circuits 30, in which no winding is contained, are mounted before and behind in the progressive direction of the slots, into which the windings on the primary side are installed, in the primary side 161. Field flux is excited effectively by a three-phase winding current by the magnetic circuits 30. The secondary side 162 represents one of split magnetic fluxes 1 obtained by dividing the magnetic path of a magnetic pole into nine magnetic paths, and a soft magnetic material is used as the quality of material. Magnetic insulating sections 2 as magnetic insulating means as the nonmagnetic sections of the magnetic path of the magnetic pole are set up among the split magnetic paths 1 as the magnetic sections of the magnetic path of the magnetic pole in a stratiform manner, and composed of a nonmagnetic material such as a resin layer, an air layer, etc.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improved linear motor which drives in a substantially linear manner.

[0002]

2. Description of the Related Art As conventional linear motors, there are several types of linear motors depending on their purposes. FIG.
Shows the basic configuration of a general linear motor. The linear motor is composed of a mover 61 and a stator 62. The mover 61 is movable in the direction of the arrow and is referred to as the primary side in this description. The stator 62 has a length corresponding to the moving stroke of the linear motor, and is referred to as the secondary side in this description. Of course, the mover and the stator may be either the primary side or the secondary side.

FIG. 16 is a sectional view of a conventional linear motor in the traveling direction.

The primary side 61 is formed by laminating electromagnetic steel plates, and each slot has three-phase AC windings U1, U2, V1,
V2, W1 and W2 are wound, and the winding diagram thereof is as shown in FIG. 17 when the number of windings is 1 turn. Usually, the number of windings is several tens of turns. The connection of each phase winding is a star winding, and in the case of an AC rotating machine, it corresponds to the windings 21, 22, and 23 represented by symbols as shown in FIG. 18, U1-U2,
It is each winding wire of V1-V2 and W1-W2. U, V, and W in the figure are terminals of each winding.

The secondary side 62 has a permanent magnet 19 and its magnetic path 2.
It is composed of 0 and. The magnetic poles on the secondary side 62 are arranged so that the N poles and S poles of the permanent magnets alternately face the primary side 61 as shown in the figure.

Next, the operation will be described.

The position of the secondary magnetic pole in the moving direction of the linear motor is defined as the X axis, and one of the magnetic pole boundary positions at which the secondary magnetic pole changes from the S pole to the N pole when moving in the positive direction of the X axis is X =
Defined as 0. The magnetic flux density B of the magnetic pole on the secondary side 62 is shown in FIG.
As shown in (a), it is assumed that the cycle is a sine wave with a magnetic pole pitch PP, that is, an electrical angle of 360 degrees and an amplitude B0, according to the X-axis position. On the other hand, the position RP on the primary side 61 is
The slider position when the winding of U1 is at the position of X = 0 is defined as RP = 0.

FIG. 19 (b) shows the three-phase windings for each phase.
Three-phase alternating current IU, IV, as shown in (c) and (d)
When IW is passed, thrust FF is generated in the plus direction of the X axis according to Fleming's left-hand rule.

[0009]

## EQU1 ## B = B0.SIN (X) IU = IA.SIN (RP) IV = IA.SIN (RP-120.degree.) IW = IA.SIN (RP-240.degree.) FF = B.I.L = [B0 / SIN (RP) / IA / SIN (RP) +
B0 ・ SIN (RP-120 °) ・ IA ・ SIN (RP
-120 °) + B0 ・ SIN (RP-240 °) ・ IA
・ SIN (RP-240 °)] ・ WT ・ 2 ・ WL = 3 ・ B0 ・ IA ・ WT ・ WL Where, the number of turns of each phase winding of WT, each winding of WL 1 /
It is a 2-turn effective winding length. The above equations are collectively referred to as equation (1).

The magnitude of thrust is as shown in equation (1),
As is well known in the theory of three-phase AC rotating machines, a thrust force FF proportional to the amplitude IA of the three-phase AC current can be obtained regardless of the X-axis position, and within the control range shown here, a good thrust FF can be obtained. Control characteristics can be obtained.

FIG. 20 shows a sectional view in the traveling direction of another conventional example. The primary side 61 is the same as in FIG. The secondary side 65 has a structure in which magnetic poles of salient pole structure made of a soft magnetic material are continuously arranged as shown in the figure. The operation of this linear motor is based on the three-phase windings U1, U2, V1, V on the primary side 61.
The force that magnetically attracts the salient pole central portion 24 of the secondary side 65 to the portion where the maximum value of the magnetomotive force created by 2, W1 and W2 is located is used as the thrust generated by the linear motor. Therefore, the thrust can be generated in any direction by shifting the phase of the three-phase current, and the position can be controlled. The magnitude of the thrust has a value related to the magnitude of the relative phase and the magnitude of the three-phase current.

FIG. 21 shows a sectional view in the traveling direction of an example of a linear motor driven by the principle of a stepping motor as another conventional example. The primary side 63 has four-phase windings A, B, C, and D. For example, the B-phase winding is wound around portions B1 and B2, and further wound in series around B3 and B4 in reverse winding. As shown, the magnetic flux induced in the B-phase winding passes through the B-phase winding, passes through the secondary side 64, and draws a loop.

The driving principle of the linear motor shown in FIG. 21 is, for example, when the primary side 63 is driven in the X direction, a current is supplied to the B phase as shown in the drawing, and a magnetic attraction force sequentially acts as the position moves. It energizes the winding.

[0014]

In the conventional example shown in FIG. 16, a large thrust force can be generated relatively efficiently, although it depends on the performance of the permanent magnet. However, for example, when a rare earth magnet or the like having good characteristics is used, the permanent magnet is expensive and the cost is high, and a member for fixing the permanent magnet is required, and an assembling cost is high.

Characteristically, since the permanent magnet is a constant field magnet, the drive speed is limited due to the voltage limitation of the linear motor which can be driven by the power supply voltage of the linear motor driving device. In other words, there is a problem that the drive speed is limited as in the high speed rotation limit of the permanent magnet type DC motor or the permanent magnet type synchronous motor. As a countermeasure against this, there is a method of reducing the number of windings and lowering the induced voltage. In this case, however, it is necessary to increase the drive current value in order to obtain the same thrust, and it is necessary to increase the drive current capacity of the drive device. Come on. That is, there is a trade-off relationship between the drive speed limit and the drive device capacity.

Another problem is that the permanent magnet is demagnetized when a large current is supplied to obtain a large instantaneous thrust.

The problems of the conventional example shown in FIG. 20 are that it is difficult to obtain a large thrust, and the thrust varies with the driving position, which tends to cause thrust ripple and drive noise. It can be considered that the reason why a large thrust cannot be obtained is that the position of the magnetic flux center of the magnetic pole easily changes depending on the magnitude and phase of the winding current because the entire magnetic pole on the secondary side is a non-directional magnetic material. it can. The cause of thrust ripple and driving noise is considered to be that the magnetic resistance on the secondary side when viewed from the primary side changes greatly because the shape of the magnetic pole on the secondary side and the slot on the primary side are discontinuous. be able to.

The problems of the conventional example shown in FIG. 21 are that it is difficult to obtain a large thrust force, the thrust force varies depending on the driving position, and a thrust ripple and a driving noise are easily generated. The energization duty is about 1 in the case of Fig. 21.
The driving efficiency is low as much as / 4, and the magnetic attraction force due to the increase and decrease of the magnetic flux excited by each phase winding is the source of this linear motor thrust. That is, the energy supply of the target thrust has the same phase, and the load on the power device of the drive device is large.

The present invention has been made to solve the above problems, and an object thereof is to make it difficult for the field magnetic flux to be adversely affected by the motor current component in the direction in which the secondary magnetic pole faces. Low thrust ripple, high peak torque,
It is to provide a linear motor that achieves a high power factor, high efficiency, and low price.

[0020]

In order to achieve the above object, the invention according to claim 1 comprises a secondary side and a primary side which is relatively movable in the longitudinal direction of the secondary side. In the linear motor described above, the primary side has a wound multiphase winding of two or more phases, and the secondary side has a plurality of magnetic poles.
The magnetic pole divides the magnetic path from each magnetic pole into a plurality of magnetic poles, reduces the magnetic resistance from each magnetic pole to the adjacent magnetic poles, and increases the magnetic resistance in the magnetic poles seen from both ends of each magnetic pole in the linear motor driving direction. And an insulating means.

According to a second aspect of the present invention, in a linear motor having a secondary side and a primary side that is relatively movable in the lengthwise direction of the secondary side, the primary side is wound. In addition, the secondary side has a plurality of magnetic poles, and each magnetic pole has a plurality of magnetic paths of the magnetic poles communicating between adjacent magnetic poles. The magnetic resistance between both ends of each magnetic pole in the linear motor drive direction is larger than the magnetic resistance of a magnetic path communicating between adjacent magnetic poles.

According to a third aspect of the present invention, in the linear motor according to the second aspect, a plurality of magnetic paths of the secondary magnetic poles are formed by removing a part of a magnetic steel plate to form a magnetic insulating portion in the magnetic poles. It is characterized in that the steel plates are arranged substantially parallel to the driving direction of the linear motor and are laminated in a direction perpendicular to the driving direction of the linear motor.

According to a fourth aspect of the present invention, in the linear motor according to the second aspect, the secondary magnetic pole has a structure in which electromagnetic steel plates arranged in a direction perpendicular to the driving direction of the linear motor are laminated. And

According to a fifth aspect of the present invention, in a linear motor comprising a secondary side and a primary side that relatively moves in the longitudinal direction of the secondary side, the primary side is wound. In addition, the secondary side has a plurality of magnetic poles, and the magnetic poles have a magnetic resistance in the direction of the magnetic path to the adjacent magnetic poles. Is small, and the magnetic resistance in the magnetic poles as viewed from both ends of each magnetic pole in the linear motor driving direction is large and is composed of a member having magnetic directionality.

According to a sixth aspect of the present invention, in the linear motor according to the fifth aspect, the magnetically directional member has a structure in which a rod-shaped magnetic member and a non-magnetic member are bundled.

According to a seventh aspect of the present invention, in the linear motor according to the first to sixth aspects, a plurality of combinations of the primary side and the secondary side, or one of the primary side and the secondary side is provided. It is characterized by sharing the department.

According to an eighth aspect of the present invention, in the linear motor according to the first to seventh aspects, the primary side winding is provided on one or both of the front and rear of the traveling direction of the portion where the winding is provided. It is characterized in that a magnetic circuit for passing a magnetic flux excited by is provided.

[0028]

The magnetic flux generated inside the linear motor is easily generated along a plurality of magnetic paths on the secondary side, and the magnetic circuit structure has a large magnetic resistance in the other direction. It can be generated at a position almost synchronized with.

Therefore, even if a current component for generating thrust is passed to a position where the field magnetic flux exists, the field magnetic flux is not disturbed to a small extent, a current interlinking with the magnetic flux can be passed, and thrust can be efficiently obtained. You can

When a large energizing current is supplied to the primary side in order to obtain a particularly large thrust, the position of the field magnetic flux hardly changes and a large thrust can be obtained.

Regarding the thrust ripple depending on the location of the thrust, in terms of magnetic resistance and internal magnetic energy, in the linear motor according to the present invention, the change in the total magnetic resistance of each three-phase winding depending on the position X, The thrust ripple can be reduced because of the geometric structure that can reduce the change in internal magnetic energy depending on the position X of the linear motor.

[0032]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of the linear motor of this embodiment in the driving direction, in which magnetic poles are adjacent to each other in the driving direction. Each magnetic pole range is the range shown as S pole, N pole, S pole, N pole, S pole, N pole in FIG.

Similar to the conventional example shown in FIG. 16, the primary side 161 is formed by laminating electromagnetic steel sheets, and each slot is wound with a three-phase AC winding. The primary side 161 of FIG.
In comparison with the conventional example, the magnetic circuit 30 has no winding before and after the slot provided with the winding on the primary side in the traveling direction.
Is provided. The magnetic circuit 30 before and after the linear motor advancing direction effectively excites the field magnetic flux by the three-phase winding current. If there is no magnetic circuit before and after this traveling direction, a part of the field magnetic flux will be lost depending on the position on the primary side, and the thrust will be partially reduced by that amount. Also becomes.

Since the empty slot in which the winding is not provided is not used, it can be eliminated by covering it with a magnetic substance. Further, the magnetic circuit 30 may be provided either before or after the traveling direction, and the number of magnetic circuits 30 to be arranged may be appropriately adjusted. Although FIG. 1 shows an example in which there are one set of concentrated windings and three-phase windings in the length of the traveling direction, similar characteristics can be obtained even in multi-phase windings other than three-phase, such as two-phase, four-phase, and five-phase windings. You can get it. As for the winding method, an example of concentrated winding is described, but of course distributed winding is possible, and various winding deformations such as lap winding are possible.

The size of the primary side also has a structure in which a plurality of units shown in FIG. 1 are connected according to the size of the desired thrust,
It is also possible to connect each phase winding in series. In terms of magnetic characteristics, the primary side and the secondary side can be relatively skewed to reduce magnetic discontinuity. The overall structure is not limited to the structure in which the rectangular parallelepipeds face each other as shown in FIGS. 15 and 1.

The secondary side 162 is one of the divided magnetic paths 1 obtained by dividing the magnetic path of the magnetic pole into nine magnetic paths, and is made of a soft magnetic material. Further, a magnetic insulating portion 2 which is a non-magnetic portion of the magnetic pole magnetic path and serves as a magnetic insulating means is provided in layers between the divided magnetic paths 1 which are the magnetic portions of the magnetic pole magnetic path, and the magnetic layer such as a resin layer or an air layer is not formed. It is made of magnetic material. The length of the secondary side 162 is 4 in FIG.
Although only the length of the magnetic pole is shown, the length is required for the size of the driving stroke of the linear motor.

First, the field magnetic flux will be described.

In FIG. 1, when a current is applied to the primary winding at a position facing the boundary of the magnetic poles, a magnetic flux is excited in each magnetic pole, and the magnetic poles of S pole, N pole or reverse polarity as shown in the figure. Is generated. The primary side current component at a position facing the magnetic pole boundary between the magnetic poles will be referred to as a field current component.

When an electric current is passed through the primary winding at a position facing the center of the magnetic pole, the magnetomotive force due to this electric current acts in the direction interlinking with the magnetic insulating layer 2, and the magnetic resistance in this direction is large. The magnitude of the magnetic flux component excited by this current component is small. The primary side current component at a position facing the center position of the magnetic pole will be referred to as an armature current component.

Next, the operation of the field when the field current component and the armature current component are superimposed and flowing will be described.

First, assuming that the field current component has already flowed and the field magnetic flux exists in each magnetic pole, and assuming that the armature current component is then increased from zero, as described above, Since the magnetic resistance is large in the direction in which the magnetomotive force due to the armature current component works and the magnetic flux is less likely to be generated, the field magnetic flux is not significantly affected by the armature current component.
At this time, the thrust of the linear motor is generated due to the relationship between the armature current component and the field magnetic flux interlinking with the armature current component.

Next, the thrust generated by the linear motor will be described using mathematical expressions.

The basic concept of the thrust generated by the linear motor, the injected electric energy, the internal energy of the linear motor, etc. is as follows.

[0045]

[Equation 2] [ΔX injected electric energy during minute displacement EIN] − [internal loss ECS] = [generated thrust FF] × [minute displacement ΔX] + [ΔX change in internal energy when slightly displaced ΔEST] (2) Now, in order to simplify the explanation, it is assumed that [internal loss ECS], that is, copper loss, iron loss, etc., is zero. [ΔX change in internal energy when minute displacement ΔEST] is important in the case of a device structure or control system in which the internal energy changes greatly, but now the internal energy does not change much. Let us consider the case and assume that this term is zero. Under such a precondition, the equation (2) is as follows.

[0046]

## EQU00003 ## [.DELTA.X injected electric energy EIN during minute displacement] = [generated thrust FF] .times. [Minute displacement amount ΔX]. It becomes an expression.

[0047]

EIN = [voltage VG induced in winding] × [current value IX applied to winding] × ΔTM = WT × ΔFL / ΔTM × IX × ΔTM (4) where WT Is the number of turns of the winding wound around this electric machine, ΔFL is the change in magnetic flux of this winding when ΔX is slightly displaced, ΔTM is the time when ΔX is slightly displaced, and IX is energized to this winding. Current value.

On the other hand, the following relational expression holds for the mechanical output of this electric machine.

[0049]

[Equation 5] EIN = [Force FF generated in the displacement direction] × [Small displacement ΔX] (5) From the equations (4) and (5), the relational expression of the generated force FF is as follows. You can ask.

[Equation 6] EIN = WT × ΔFL / ΔTM × IX × ΔTM
= FF × ΔX, FF = WT × ΔFL / ΔX × IX (6) In summary, the mechanical output FF of the electric machine is the number of turns WT of the winding and the current value IX flowing through the winding. Small displacement △
The amount of change in the magnetic flux that is linked to the winding when moving X
It can be expressed as the product of FL / ΔX.

Further, since the relational expressions of the equations (4), (5) and (6) use only a simple and clear relational expression that the injected energy is the product of the induced voltage and the current, for example, the winding When there are multiple sets such as the three-phase windings in Fig. 1, the analysis method for each winding is to apply Equation 6 to the relationship between each winding current and the interlinkage magnetic flux, and add up the respective thrusts. You can ask for it.

Further, the current I flowing in one winding is
When X is decomposed into two currents of IX = IX1 + IX2, it is possible to apply equation (6) to IX1 and IX2, respectively, and add the results. That is, specifically, the result is the same even if one-phase current is considered by vector decomposition into a field current component and an armature current component, and each is calculated by the equation (6) and then added.

Further, in the equation (6), as a specific condition, it is assumed that the slot and the tooth portion have a uniform magnetic flux density B, and the length of the portion interlinking with the magnetic flux of one turn of the conducting conductor is the length. Considering the case of L,

## EQU7 ## Since ΔFL = B × L × ΔX, FF = WT × ΔFL / ΔX × IX = WT × B × L × IX (7), which is completely the same as Fleming's left-hand rule. It can be transformed into the same formula. That is, it can be said that the formula (6) is a general formula that holds even when the distribution of the magnetic flux is not uniform.

In the above description, the thrust FF has been shown to be calculated from the correlation between each phase current and the magnetic flux linking the current. However, the thrust FF is calculated between the winding and the magnetic flux through which each phase current flows. Power does not work. In particular, when each phase winding is surrounded by magnetic material as shown in Fig. 1, the force is on the primary side 1
It can also be observed as an attractive force acting between magnetic lines of force existing between 61 and the secondary side 162.

Further, as described above, the equations (6) and (7)
The condition that is satisfied is that [ΔX internal energy change ΔEST when slightly displaced] is small and can be ignored.

Next, in order to describe the characteristics of the linear motor in the present embodiment, a control method including an example of the controller will be described.

FIG. 2 shows an example of a linear motor control device in this embodiment.

In FIG. 2, the control device has a primary side 161.
The relative position between the secondary side 162 and the
The position detector 163 that outputs S, the position detection circuit 55 that detects the position signal RP from the detection signal DS, and the detection signal D
A speed detection circuit 56 for detecting the speed signal SD from S and a speed error signal ES by subtracting the speed signal SD from the speed command SI
And a speed control unit 57 that creates a thrust command SA by performing PID compensation or the like on the speed error signal ES.
And have.

Further, the control device has a field current command circuit 59 which inputs the speed signal SD and the position signal RP and outputs the field current commands SFIU, SFIV, SFIW of the three phases U, V, W. Have

Now, letting SF be the amplitude of the field current command,
The three-phase field current component is

## EQU8 ## SFIU = SF.SIN (RP-90.degree.) SFIV = SF.SIN (RP-90.degree.-120.degree.) SFIW = SF.SIN (RP-90.degree.-240.degree.) Note that the above equations are collectively referred to as equation (8).

The amplitude SF of the field current command is a value in which the field magnetic flux of each magnetic pole is physically close to the saturation magnetic flux density in the speed range of the constant thrust region, that is, in the range of the speed signal SD from zero to the constant speed VLC. The maximum value SFMX is such that the maximum amplitude value SFMX of the field current command is obtained when the speed is equal to or higher than the constant speed VLC.
To a value that decreases in inverse proportion to the speed SD. In a usual design, the induced voltage of each winding is often designed to be the maximum voltage that can be driven by the control device at a constant speed VLC. At a constant speed VLC or higher, the induced voltage in each winding is proportional to the product of the magnitude SF of the field magnetic flux and the speed SD. Therefore, at a constant speed VLC or higher, the induced voltage in each winding has a substantially constant value. It is the maximum voltage that can be driven by the controller. The unit of the position signal RP is represented by the electrical angle of the linear motor, and the winding position of the U1 with respect to the secondary magnetic pole is U1 at the position of RP = 0, assuming that the winding position moves in the plus direction of the position signal RP in FIG. Is located at the boundary of the magnetic pole where the secondary magnetic pole changes from the N pole to the S pole.

The armature current command circuit 58 receives the three-phase armature current commands SAIU and SAIV with the current amplitude command SA and the position signal RP which are proportional to the thrust command value when the speed is less than the constant speed VLC. , SAIW are output.

[0062]

## EQU9 ## SAIU = SA.SIN (RP) SAIV = SA.SIN (RP-120.degree.) SAIW = SA.SIN (RP-240.degree.) The above formulas are collectively defined as formula (9). Adder 72,
Reference numerals 73 and 74 respectively add a three-phase field current command and a three-phase armature current command to generate a three-phase current command SIU, SIV, SI.
W is output to the current control circuit 60.

[0063]

## EQU10 ## SIU = SFIU + SAIU SIV = SFIV + SAIV SIW = SFIW + SAIW The above equations are summarized as equation (10). Formula (10)
As another calculation method, the field current component and the armature current component are represented as respective vectors, the two vectors are vector-added to obtain a combined vector, and three-phase distribution is performed based on the amplitude and phase of the combined vector. Phase current command SIU, SI
Even if V and SIW are obtained, the result will be the same value.

Further, the current control circuit 60 amplifies the power and drives the drive current IU, to each three-phase winding U, V, W of the linear motor.
Flow IV and IW. Let us consider the specific magnetic flux distribution at this time, the current value of each phase, and the generated thrust.

The magnetic pole position on the secondary side 162 is represented as the X-axis as shown in FIG. 1, and from the S pole to the N side in the positive direction of the X-axis.
Let X = 0 be a boundary point that changes to a pole. Also, the detector 1
The primary side position RP detected by 63 is RP = 0 when the winding U1 is at the position X = 0. Further, for simplification of description, it is assumed that the magnetic flux distribution generated in the linear motor is a sine wave distribution, and when RP = 360 degrees, the magnetic flux distribution is as shown in FIG. To be precise, in the model of FIG. 1, the magnetic path on the secondary side 162 is missing at both ends of the primary side 161 on the X axis, and the magnetic flux distribution as shown in FIG. The method of compensating for the disturbance will be described later, and will be described assuming that the magnetic flux distribution is as shown in FIG. Actually, the primary side 161
When a plurality of MP sets of three-phase AC windings are arranged in series in the X-axis direction, the error in the output thrust of the linear motor due to the disturbance of the magnetic flux at both ends of the primary side 161 is relatively small as 1 / MP. Become. In addition, three or more sets of three-phase AC windings are connected in series in the X-axis direction on the primary side 161.
It can also be seen that the AC winding portion of the set is cut off and expressed on the primary side 161 in FIG. Formulas (8), (9), (1
The currents of the respective phases shown in (0) are (b), (c), and
It becomes like (d).

When such an operation is performed, the field current components SFIU, SFIV, SFIW expressed by the equation (8) are
In the linear motor of FIG. 1, the magnetic motor on the secondary side 162 is always operated so as to generate the field magnetic flux shown in FIG. The armature current component SAIU, SA represented by formula (9)
IV and SAIW flow so as to intersect with this magnetic flux at right angles. Since the magnetic resistance in the direction of the magnetomotive force on which the armature current component acts is large, the influence of the armature current component on the field magnetic flux is small as already described.

The thrust FF generated at this time will be described. Considering that the distribution of the field magnetic flux is also a sinusoidal distribution on the primary side 161, the formula (7) will be considered.

First, when the equation (7) is applied to each three-phase winding for the thrust force FFF of the field current component, the following equation is obtained.

[0069]

[Expression 11] FFF = B · I · L = [B0 · SIN (RP) · SF · SIN (RP−90 °) + B0 · SIN (RP−120 °) · SF · SIN (RP-90 ° −120 °) ) + B0.SIN (RP-240.degree.). SF.SIN (RP-90.degree.-240.degree.)]. WT.2.WL = 0 .. (11) Therefore, the field current component does not generate thrust.

Next, when the equation (7) is applied to each three-phase winding for the thrust FFA of the armature current component, the following equation is obtained.

[0071]

[Formula 12] FFA = B · I · L = [B0 · SIN (RP) · SA · SIN (RP) + B0 · SIN (RP-120 °) / SA · SIN (RP-120 °) + B0 · SIN (RP -240 °) ・ SA ・ SIN (RP-240 °)] ・ WT ・ 2 ・ WL = 3 ・ B0 ・ IA ・ WT ・ WL ・ ・ (12) As a result, it is optional by variably controlling B0 and IA. It is possible to generate thrust of. For example, if the control shown in FIG. 2 is performed, good speed control is realized. In principle, there is no thrust ripple. As for the peak thrust, since the formula (12) is satisfied in the range where the armature current component does not disturb the field magnetic flux significantly, the magnetic insulation design of the secondary side 162 is performed so that the field flux is less likely to be disturbed by the armature current component. If designed, a large peak thrust can be obtained practically. Further, it is understood that the formula (12) has the same form as the formula (1) and the thrust is generated by the same principle. The functionally different point is that in this embodiment, the field current component can be freely controlled by the formula (1
2) B0 can be controlled.

To be precise, it is necessary to add the thrust of the linear motor to the component of which [ΔX internal energy change ΔEST when slightly displaced] is a mechanical output. Compared with the present embodiment of FIG. 1, the conventional example of FIG. 21 is a linear motor of a type in which [internal energy change ΔEST when ΔX is slightly displaced] is large, and this component cannot be ignored.

FIG. 4 shows another embodiment according to the present invention.

The primary side 261 corresponds to 161 in FIG. 1, but the front and rear of the traveling direction are described by a chain double-dashed line and omitted. Actually, a plurality of units separated by a two-dot chain line shown in FIG. 4 are connected, and further a magnetic circuit before and after the traveling direction as shown in FIG. 1 is added.

The secondary side 262 includes the divided magnetic path 3 and the magnetic insulating portion 4.
In comparison with FIG. 1, the part of the secondary side facing the primary side is partially magnetically connected.

The secondary side 262 is concretely constructed by removing the outer shape of the electromagnetic steel sheet having the shape shown in FIG. The structure is such that the layers are stacked in a direction perpendicular to each other, that is, the structure is stacked from the front side to the back side of the paper in FIG.

In terms of manufacturing problems, the effect of this structure is that when the secondary side 162 of FIG. 1 is a stack of electromagnetic steel plates having the shape of FIG. 1, a plurality of electromagnetic steel plates are formed by pressing. It becomes difficult to assemble because it is divided into parts,
In the case of the shape shown in FIG. 4, a part of them are connected and can be handled as one sheet metal, and the sheet metals can be simply laminated so that the assembly is easy.

Further, magnetically, although there is a drawback that leakage magnetic flux is generated in the rotating direction on the magnetic pole surface on the secondary side 262, the magnetic flux density on the magnetic pole surface is averaged and the ripple of the linear motor thrust is reduced. effective.

FIG. 5 shows a linear motor of the present invention which is designed so that the magnetic resistance at the boundary between adjacent magnetic poles is increased so that the position of the magnetic flux of the magnetic poles is less likely to change. 261 is the primary side, 3
Reference numeral 62 is a secondary side combined by the divided magnetic path 5 and the magnetic insulating portion 6. A recess is formed at the boundary of the magnetic pole on the secondary side 362 to make the magnetic resistance at the boundary of the magnetic pole have a larger value, thereby preventing the magnetic flux of each magnetic pole from being deviated by the armature current component.

In the linear motors of FIGS. 1, 4 and 5, it is also possible to partially provide a connecting portion in each magnetic path within the range in which the leakage magnetic flux does not cause a problem for the purpose of reinforcing the secondary side.

FIG. 6 shows another embodiment according to the present invention.
1 is simplified to provide a magnetic insulating portion 8 at the center of the magnetic pole on the secondary side 462 to reduce the disturbance due to the armature current component of each magnetic pole field flux. Reference numeral 7 is a divided magnetic path.

FIG. 7 shows an example in which the secondary side 562 is connected to only a part of each of the divided magnetic paths 7 shown in FIG. 6. The leakage flux at the connecting portion is not preferable, but the amount thereof is the whole. Since it is only a part of the above, it does not pose a big problem in practical use. Reference numeral 9 is a divided magnetic path, and 10 is a magnetic insulating portion.
Similar to the linear motor of FIG. 4, if the secondary side 562 has a laminated structure of electromagnetic steel plates, it is easy to manufacture.

FIG. 8 shows another embodiment according to the present invention.
Reference numeral 14 denotes a U-shaped electromagnetic steel plate as shown in FIG. 11. The electromagnetic steel plates 14 having slightly different sizes are stacked in a direction perpendicular to the driving direction of the linear motor to form a secondary side 662.
Is composed. When the magnetic steel sheet 14 is a magnetic steel sheet magnetically oriented in the direction of the arrow shown in FIG. 11, it means that the split magnetic path is constituted only by the magnetic steel sheet magnetically oriented. The magnetic resistance between the adjacent magnetic poles is small, and the magnetic resistance inside the magnetic poles as viewed from between both ends of each magnetic pole in the linear motor driving direction is large by only laminating the magnetic poles with each other. It is possible to obtain the characteristics according to the purpose.

In addition, in the linear motor of FIG.
By sandwiching the magnetic insulating plate having a large magnetic resistance of the shape shown in FIG. 11 between the laminated electromagnetic steel plates having the shape of 1, the magnetic resistance between both ends of each magnetic pole is made larger, and the characteristics of the linear motor are improved. I can do things. The magnetic insulating plate having a large magnetic resistance may be replaced by an air gap, and it is preferable that the linear motor characteristic has a larger magnetic resistance. When sandwiching the magnetic insulating plate having a large magnetic resistance, it is not always necessary that the magnetic steel plates are magnetically oriented electromagnetic steel plates.

Further, in the linear motor of FIG. 8, when the magnetic flux of the magnetic poles is apt to change in its traveling direction, eddy current flows in the electrical steel sheet and eddy current loss occurs, so as shown in FIG. Therefore, it is also effective to make a slit in the magnetic steel sheet.

FIG. 10 shows another embodiment according to the present invention in which the secondary side 762 has a high relative magnetic permeability in the direction of the arrow and a low relative magnetic permeability in the other direction.

Further, an example of a concrete material of the divided magnetic paths 12 and 13 has a shape as shown in FIG. 12, and has a structure in which a rod-shaped electromagnetic member 15 is bound by a non-magnetic member 16 such as resin. Has become.

In addition to the form of the linear motor as described above, it is also possible to combine a plurality of sets of the primary side and the secondary side, or to share a part of the primary side or the secondary side.

FIG. 13 shows an example in which two sets of the linear motors shown in FIG. 1 are combined. Since the yoke part of the secondary side 862 is shared, two sets of the linear motors shown in FIG. 1 are arranged in parallel. It has been miniaturized. Reference numeral 17 is a divided magnetic path, and 18 is a magnetic insulating portion. Further, since the magnetic attraction force exerted on the secondary side 862 is received from both opposite directions, there is an effect that it is canceled and only a thrust force only in the driving direction is produced.

Thus, by combining a plurality of linear motors, it is possible to reduce the size and cancel the magnetic attraction force by sharing some members.

In FIG. 14, the linear motor shown in FIG. 4, which is an embodiment of the present invention, is combined back to back on the primary side 261 and the winding method is U-phase winding from U1 to U.
2, U3 to U4, V-phase winding is V1 to V2, V3 to V4, W-phase winding is W1 to W2, W3 to W4 to shorten coil end and simplify winding. / Realization of simplification. In addition, the secondary side 26
There is also an effect that the suction force applied to the direction 2 other than the traveling direction is canceled by the two sets of linear motors. Similarly, a plurality of linear motors according to the present invention are combined to share some members,
You can obtain the effect of canceling unnecessary power.

Although various embodiments according to the present invention have been described above, various modifications can be made on both the primary side and the secondary side, and are included in the present invention.

For example, there are various methods for the number of winding phases, the number of magnetic poles, the winding method, etc., and the selection can be made according to the needs.

Further, in order to reduce the ripple of the thrust of the linear motor, one or both of the primary side and the secondary side are skewed, or a technique used in a usual electric motor such as slightly changing the pitch between magnetic poles is applied. Of course, it is possible to do it.

Also, an example in which the primary side and the secondary side face each other on a flat surface has been described, but a curved surface shape, a cylindrical shape, a polygonal shape or the like can be deformed.

Further, it is possible to further reduce the ripple of thrust by skewing the primary side and the secondary side relatively.

In the present embodiment, the case where the secondary side is fixed and the primary side is movable has been described, but it is a relative movement, and either one may be fixed.

Regarding the stroke, it is also possible that the secondary side is short and the primary side has a length corresponding to the stroke of the linear motor.

In particular, when wiring to the movable side is difficult and it is desired to make the movable side extremely lightweight, a method in which the primary side is held long by the length of the stroke and fixed and the secondary side is shortened to make the movable side is possible. It is valid. However, in this case, since the primary side, which has a complicated configuration, is lengthened, it is disadvantageous in terms of cost.

Although the present invention refers to a linear motor as the driving direction, it is possible to drive not only in a straight line but also in a curved line, and to drive in an arc shape.

[0101]

According to the present invention, in a permanent magnet type linear motor, an expensive permanent magnet is not required, which reduces cost, a member for fixing the permanent magnet is required, assembly is not required, cost is reduced, and field control is performed. Since the field weakening control can be performed freely, high-speed control can be realized without increasing the capacity of the driving device, reducing the total system cost, and there is no demagnetization phenomenon of the permanent magnet, resulting in high reliability. .

In the so-called salient pole type reluctance type linear motor of the present invention, the driving efficiency is good,
A large peak thrust can be output, and in terms of driving principle, thrust ripple and noise are small, driving characteristics are good, and high-speed driving is easy.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a linear motor having a magnetic resistance directionality according to the present invention.

FIG. 2 is a configuration diagram showing a linear motor driving device in the present embodiment.

FIG. 3 is a diagram showing an operation time chart of the linear motor in the present embodiment.

FIG. 4 is a diagram showing another embodiment of the linear motor according to the present invention.

FIG. 5 is a diagram showing another embodiment of the linear motor according to the present invention.

FIG. 6 is a diagram showing another embodiment of the linear motor according to the present invention.

FIG. 7 is a diagram showing another embodiment of the linear motor according to the present invention.

FIG. 8 is a diagram showing another embodiment of the linear motor according to the present invention.

9 is a diagram showing the shapes of constituent members of the linear motor shown in FIG.

FIG. 10 is a diagram showing another embodiment of the linear motor according to the present invention.

11 is a diagram showing the shapes of constituent members of the linear motor shown in FIG.

FIG. 12 is a diagram showing the shapes of constituent members of the linear motor shown in FIG.

FIG. 13 is a diagram showing an example in which two sets of linear motors are combined in this embodiment.

FIG. 14 is a diagram showing an example in which two sets of linear motors in this embodiment are combined.

FIG. 15 is a diagram showing an example of a general appearance of a linear motor.

FIG. 16 is a diagram showing a conventional linear motor.

17 is a winding diagram of the linear motor shown in FIG.

18 is a diagram modeling a winding of the linear motor shown in FIG.

19 is a diagram showing an operation time chart of the linear motor shown in FIG.

FIG. 20 is a diagram showing another conventional linear motor.

FIG. 21 is a diagram showing another conventional linear motor.

[Explanation of symbols]

1,3,5,7,9,12,13,17 Split magnetic path 2,4,6,8,10,18 Magnetic insulating part 14 Electromagnetic steel sheet 15 Electromagnetic member 16 Non-magnetic member 61,161,261 Primary side 62, 162, 262, 362, 462, 562, 66
2, 762, 8622 Secondary side U1, U2 U-phase winding V1, V2 V-phase winding W1, W2 W-phase winding X Driving direction

Claims (8)

[Claims] 1. A linear motor comprising a secondary side and a primary side that relatively moves in the lengthwise direction of the secondary side, wherein the primary side is a multi-phase winding having two or more phases. A phase winding, the secondary side has a plurality of magnetic poles, and the magnetic pole divides a magnetic path from each of the magnetic poles into a plurality of magnetic poles, and the magnetic resistance from each magnetic pole to an adjacent magnetic pole is small. And a magnetic insulating means for increasing the magnetic resistance in the magnetic poles as seen from both ends of each magnetic pole in the linear motor driving direction. 2. A linear motor composed of a secondary side and a primary side that relatively moves in the lengthwise direction of the secondary side, wherein the primary side is a multi-phase winding having two or more phases. A phase winding, the secondary side has a plurality of magnetic poles, and each magnetic pole is divided into a plurality of magnetic paths of magnetic poles communicating between adjacent magnetic poles. A linear motor characterized in that a magnetic resistance between both ends of each magnetic pole is larger than a magnetic resistance of a magnetic path communicating between adjacent magnetic poles. 3. The linear motor according to claim 2, wherein a plurality of magnetic paths of the secondary magnetic poles are formed by removing a part of a magnetic steel plate to form a magnetic insulating portion in the magnetic pole, and driving the magnetic steel plate to drive the linear motor. A linear motor having a structure in which the linear motors are arranged substantially parallel to each other and stacked in a direction perpendicular to the driving direction of the linear motor. 4. The linear motor according to claim 2, wherein the secondary magnetic pole has a structure in which electromagnetic steel sheets arranged in a direction perpendicular to the driving direction of the linear motor are laminated. 5. A linear motor comprising a secondary side and a primary side that relatively moves in the lengthwise direction of the secondary side, wherein the primary side is a multi-phase winding having two or more phases. A phase winding is provided, the secondary side has a plurality of magnetic poles, and the magnetic poles have a small magnetic resistance in the direction of the magnetic path to the adjacent magnetic poles, and a linear motor drive The linear motor is characterized in that the magnetic resistance in the magnetic poles as seen from both ends of each magnetic pole in the direction is composed of a member having a large magnetic directional property. 6. The linear motor according to claim 5, wherein the magnetically directional member has a structure in which a rod-shaped magnetic member and a non-magnetic member are bundled together. 7. The linear motor according to claim 1, wherein a plurality of combinations of the primary side and the secondary side or a part of the primary side or the secondary side is shared. A linear motor characterized by that. 8. The linear motor according to claim 1, wherein the primary side has a magnetic flux excited by the primary winding on one or both of front and rear of a traveling direction of a portion where the winding is provided. A linear motor characterized by having a magnetic circuit for passing through.