JPH1169763A - Shaft-type linear motor and drive method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft-type linear motor which is provided with a barshaped stator, containing filed magnets and a mover provided with an armature coil, and can be efficiently driven with less fluctuation in thrust and with small mover width, and a drive method therefor. SOLUTION: This linear motor comprises a mover 2 provided with an armature coil 21 comprising coils Lu , Lv , Lw , a stator 1 provided with field magnets 11 a magnetic pole width of which is Pm and the north poles and south poles of which are arranged alternately. The width of each coil is set to Pm /3, and the coils are arranged, so that their center positions are shifted by Pm /3. Hall elements h1 , h2 , h3 are placed on the mover 2 in positions shifted by Pm /6 from the center positions of the respective coils. A constant current in a direction such as to generate electromagnetic force in a drive direction is passed through coils a period, from when the center positions of the coils advance by Pm /6 in the direction of drive from the upstream end in the drive direction in the direction of drive the magnetic poles to when the center positions further advance by 2Pm /3 in the drive direction, based on the polarity of the magnetic pole which each Hall element detects.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable stator which has a shaft-shaped stator having a field magnet extending in a fixed direction, and an armature coil fitted on the field magnet, and reciprocates along the stator. And a shaft type linear motor including

[0002]

2. Description of the Related Art Linear motors are used to linearly move articles in a wide range of fields such as OA equipment such as copiers, printers and image scanners, XY tables, FA equipment such as article transport devices, and optical equipment such as cameras. Used to move. Various types of linear motors have been proposed, and are applied to the above-described various devices according to the characteristics. For example, a shaft-type linear motor including a shaft-shaped stator having a field magnet and extending in a predetermined direction and a mover having an armature coil externally fitted to the field magnet is a shaft-shaped fixed motor. There is an advantage that the child can be used as a guide member of the mover as it is, and the structure can be simplified accordingly.

Japanese Patent Application Laid-Open No. Hei 7-181601 proposes a shaft type linear motor shown in FIG. This linear motor has N on the shaft member 910.
It has a field magnet 911 in which magnetic poles of S and S poles are alternately arranged in the longitudinal direction of the member 910 at the same pitch _Pn, and an armature coil 921 fitted to the field magnet 911. This linear motor has a field magnet 9
The 11 side is the stator 91 and the coil 921 side is the stator 91
, A so-called moving coil type linear motor that is a movable element 92 that reciprocates along the axis. Armature coil 9
21 comprises three coils Lu, Lv and Lw. These coils Lu, Lv and Lw are each 2P _n /
3 is a wide, are arranged offset to the center position of each coil by 2P _n / 3.

A current is applied to each coil according to the polarity of the magnetic pole of the field magnet 911 at a position facing the coil to generate a thrust and drive the mover 92. A Hall element h as a sensor for detecting the polarity, in other words, the direction of the magnetic field formed by the magnetic pole.
u, hv and hw are arranged. JP-A-7-181
No. 601, the coils Lu, Lv, and Lw of the linear motor shown in FIG. 27 are energized as shown in FIG. Driving in the direction is shown. This linear motor is driven by a so-called three-phase full-wave system.

[0005]

However, when the linear motor shown in FIG. 27 is driven by energizing each coil as shown in FIG. 28, there are the following problems. For example,
During the section shown in FIG. 28, the coil Lu is energized in one predetermined direction, and the mover 92 including the coil is
It moves from the position shown in FIG. 27A to the position shown in FIG. In the meantime, the coil Lu moves from the N pole to the S pole so as to straddle the magnetic pole, so that the leading end in the moving direction of the coil Lu (in this example, the left direction in the drawing) is located on the S pole and the rear end is located. Are located on the N pole, so that the coil Lu, which is energized in one direction, receives an electromagnetic force in opposite directions at its leading end and trailing end. Therefore, the electromagnetic force applied to the entire armature coil 921, that is, the thrust of the linear motor decreases, and the fluctuation of the thrust at each position in the longitudinal direction of the stator increases. That is, the linear motor shown in FIG.
Driving as shown in (1) results in poor driving efficiency from the viewpoint of generated thrust, and deteriorates driving accuracy from the viewpoint of thrust fluctuation.

[0006] Apart from such a problem, in the linear motor shown in FIG. 27, the width of the mover 92 in the longitudinal direction of the stator 91 is at least the coils Lu, Lv and Lv.
w fraction of the width, i.e., requires the width of the 2P _n min, it is impossible to reduce the armature to more the direction. In some cases, in addition to the width of these three coils, the mover 92
Is required to have a width corresponding to a bearing for smoothly moving along the stator 91.

Therefore, the present invention provides a rod-shaped stator having a field magnet in which N and S poles are alternately arranged;
A shaft type linear motor having an armature coil externally fitted to the stator and a mover reciprocally movable along the stator, wherein the shaft type linear motor has a small thrust fluctuation and can be efficiently driven. It is an object to provide a motor.

Another object of the present invention is to provide such a linear motor, in which a shaft-type linear motor in which the width of the mover in the longitudinal direction of the stator can be reduced to about 1/2 of the conventional size. Another object of the present invention is to provide a method of driving a shaft-type linear motor that can drive efficiently with small fluctuations in thrust.

[0009]

SUMMARY OF THE INVENTION The present invention for solving the above problem is, the field magnet where the magnetic poles of the S pole of the magnetic pole and the width P _m of the N pole width P _m are arranged alternately in a predetermined direction Having a rod-shaped stator extending in the predetermined direction, an armature coil externally fitted to the stator, and a movable element reciprocally movable along the stator. A shaft-type linear device comprising one or a plurality of coil groups each including a first, second and third coils satisfying the following conditions (A) and (B): Provide a motor.

[0010] Condition (A): the first coil, said stator longitudinal width of the second coil and the third coil is the same, the width P _c is P _c ≦ P _m / 3. Condition (B): The center position of the second coil in the longitudinal direction of the stator is defined as P _m / 3 + j · P _m (j is an integer, that is, j = 0, ± 1, ± 2, ± 3...)
The center position of the third coil in the stator longitudinal direction is 2P from the center position of the first coil in the stator longitudinal direction to the one direction in the stator longitudinal direction.
_{m / 3 + k · P m} (k is an integer. That is k = 0, ± 1,
± 2, ± 3 ...)

The field magnet of the stator has N poles and S poles arranged alternately in the longitudinal direction of the stator. Width in the stator longitudinal direction of the magnetic poles of the magnetic pole and the S pole of the N pole is P _m. The shape of the cross section perpendicular to the longitudinal direction of the stator may be typically a circular shape, but may be a polygonal shape such as a triangle, a quadrangle, a pentagon, or an oval shape.

The armature coil includes one or a plurality of coil groups each including the first, second and third coils satisfying the above two conditions (A) and (B). . When two or more such coil groups are provided, the three coils of each group may satisfy the above two conditions (A) and (B) in a state different from the three coils of the other group. For example, when the armature coil includes two such coil groups, one of the coil groups satisfies the condition (B) with j = 0,
k = 0, and the other set of coil groups satisfies the above condition (B) with j = 1 and k = 1. The parameters j and k in the above condition (B) of each set of coil groups are represented by (j, k) = (0, 0) or (j, k).
= (-1, -1), 3
The two coils have a center position of P _m /
As a result, the width of each set of coil groups in the direction can be reduced.

[0013] More than two sets of coil groups for armature coils
If provided, different sets of coil groups in the longitudinal direction of the stator
The positional relationship of each set is determined by the condition (A)
It is optional as long as (B) is satisfied. Preferred position
Will be described later. The shaft type linear motor according to the present invention
As a method of driving the motor, the present invention relates to the first coil and the second coil.
The coils of the second coil and the third coil are
The center position in the longitudinal direction of the stator of the
Mover in the longitudinal direction of the stator of the magnetic pole of the magnetic magnet
P from the upstream end in the driving direction_S(P_c/ 2 ≦ P_S≤P
_m/ 6) 2P from the position advanced in the driving direction_m/ 3
Until the position advanced in the driving direction, the coil faces
Depending on the polarity of the magnetic pole, the coil generates electromagnetic force in the drive direction.
Characterized by flowing a constant current in the direction of occurrence
The present invention provides a method for driving a linear motor. The coil
Width P_c= P_m/ 3, the above P_SIs P _m/ 6
You.

A first coil, the center positions of the coils of the second coil and the third coil is advanced from the upstream end in the moving element driving direction in the stator longitudinal direction of the magnetic poles of the field magnet to P _S driving direction The position or the position further advanced in the 2P _m / 3 driving direction can be detected by the magnetic pole detecting element if the magnetic pole detecting element is arranged at the following position, for example.

That is, the first to sixth magnetic pole detection elements are arranged at the next positions in at least one set of coil groups. P _s + p from the center position of the first coil in the longitudinal direction of the stator in any one of the directions.
₁ · P _m (p ₁ is an integer, that is, p ₁ = 0, ± 1, ±
2, ± 3, ... _{P c / 2 ≦ P S ≦} P m / 6. However, P _S is the same value as P _S in the above driving method. A) a first magnetic pole detection element capable of detecting the polarity of the magnetic pole of the field magnet on the mover at the shifted position; The field is located on the mover at a position shifted from the center position of the first coil in the longitudinal direction of the stator in a direction opposite to the one direction in the direction by P _S + p ₂ · P _m (p ₂ is an integer). A second magnetic pole detection element capable of detecting the polarity of the magnetic pole of the magnetic magnet is provided. The second
At a position shifted from the center position of the coil in the stator longitudinal direction in the one direction in the direction by P _S + q ₁ · P _m (q ₁ is an integer), the polarity of the magnetic pole of the field magnet is set on the mover. A third magnetic pole detection element capable of detection is provided. The field is positioned on the mover at a position shifted from the center position of the second coil in the longitudinal direction of the stator in a direction opposite to the one direction in the direction by P _S + q ₂ · P _m (q ₂ is an integer). A fourth magnetic pole detection element capable of detecting the polarity of the magnetic pole of the magnetic magnet is provided. P _s + r ₁ · P _m (r ₁ is an integer) from the center position of the third coil in the longitudinal direction of the stator to the one direction in the direction.
A fifth magnetic pole detection element capable of detecting the polarity of the magnetic pole of the field magnet is provided on the movable element at the shifted position. P from the center position of the third coil in the longitudinal direction of the stator in a direction opposite to the one direction in the direction.
_A sixth magnetic pole detection element capable of detecting the polarity of the magnetic pole of the field magnet is provided on the mover at a position shifted by _S + r ₂ · P _m (r ₂ is an integer). These magnetic pole detection elements include, for example, Hall elements.

The position energizing proceeding to P _S driving direction from the upstream end in the armature drive direction center position in the lengthwise direction of the stator of each coil in the stator longitudinal direction of the magnetic poles of the field magnet is started, and The position where the energization further advanced in the 2P _m / 3 drive direction from that position is stopped,
An example of which magnetic pole detection element is detected will be described later in an embodiment.

That is, such a magnetic pole detecting element is provided.
When the driving method includes detecting the magnetic pole detecting element,
Energizing each coil based on the polarity of the magnetic pole
It is. When energized as described above, the center position of the coil
P from the upstream end of the magnetic pole in the mover drive direction_S(P_c/
2 ≦ P_S≤P_m/ 6) Energization in the drive direction is started.
Position, the coil width P_cIs P_m/ 3 or less
So that all parts of the coil face the pole
And it does not straddle both the north and south poles.
No. In addition, the current is stopped, and 2P_m/ 3 drive direction
Position, that is, the center position of the coil is
P from the upstream end of the magnetic pole in the mover drive direction _S+ 2P_m
/ 3 (≦ P_m/ 6 + 2P_m/ 3 = 5P_m/ 6) Drive direction
All parts of the coil are
Is located at a position facing the magnetic pole. That is, energize the coil
When all parts of the coil are
And its coil is located on both the north and south poles.
When straddling the pole, the coil is not energized.
No. Therefore, the energized coil is
Generates an electromagnetic force in the driving direction, and in the direction opposite to the driving direction.
Does not generate electromagnetic force. With this, the conventional linear motor
The coil is energized while straddling both poles
And in some parts of the coil the direction opposite to the drive direction
Direction of the present invention,
When the motor is driven as described above, the electrical energy is
Conversion to move the mover in the drive direction efficiently
And a driving force in the direction opposite to the driving direction is generated.
So that thrust fluctuations can be suppressed
it can.

As described above, when the magnetic pole detecting element is provided to detect the energization start position and the energization stop position for each coil, P _S in the above driving method is set to P _S = P _m
With / 6, the number of magnetic pole detection elements to be arranged can be reduced. That is, the shaft type linear motor,
In each of the first coil, the second coil, and the third coil, the center position of the coil in the stator longitudinal direction is located upstream of the magnetic pole of the field magnet in the mover driving direction in the stator longitudinal direction. P from the end _m /
6 From the position advanced in the driving direction to the position further advanced in the 2P _m / 3 driving direction, the direction in which the coil generates an electromagnetic force in the driving direction is constant according to the polarity of the magnetic pole facing the coil. When the current is supplied and the current is driven, the magnetic pole detection element may be arranged at the next position.

That is, for at least one set of coil groups, the first, second, and third three magnetic pole detection elements may be provided at the following positions. P _m / 6 + p · P _m (p is an integer; that is, p = p) from the center position of the first coil in the stator longitudinal direction in one of the directions in the direction.
(0, ± 1, ± 2, ± 3...) A first magnetic pole detection element capable of detecting the polarity of the magnetic pole of the field magnet is provided on the movable element at a shifted position. In addition, the second
P _m / 6 + q · P _m (q is an integer; that is, q = 0, ± 1, ± 2, ± 3...) From the center position of the coil in the stator longitudinal direction in the one direction in the direction. A second magnetic pole detection element capable of detecting the polarity of the magnetic pole of the field magnet is provided on the mover. Further, _Pm / 6 from the center position of the third coil in the stator longitudinal direction to the one direction in the direction.
+ R · P _m (r is an integer, that is, r = 0, ± 1, ± 2,
A third magnetic pole detection element capable of detecting the polarity of the magnetic pole of the field magnet is provided on the mover at a position shifted by ± 3. The “one direction” of “any one direction in the stator longitudinal direction” in which these magnetic pole detection elements are arranged is the “one direction” of the “one direction in the stator longitudinal direction” in the above condition (B). May be in a different (opposite) direction.

The shaft type linear motor according to the present invention
Which preferably satisfies the above conditions (A) and (B)
As a shaft type linear motor with coil arrangement,
Amoter can be mentioned. That is, the width P_mN
Pole and width P_mS poles are alternately arranged in a predetermined direction.
A bar having a covered field magnet and extending in the predetermined direction
A stator having an armature coil fitted around the stator.
And a mover reciprocally movable along the stator.
The armature coil has the same width in the longitudinal direction of the stator.
And its width P _cIs P_c≤P_m/ 3, the stator
The center position in the longitudinal direction is P_m/ 3
Of the first, second and third coils
Characterized in that one or more sets of file groups are provided.
It is a shaft type linear motor.

An armature coil is a set of the three coils.
If there are multiple sets of coil groups
Two coils arranged next to each other in a set
Are center positions in the longitudinal direction of the stator.
_mIt is preferably shifted by / 3. This way,
The center position of all the coils of the armature coil is P _m
/ 3 shifted by 3
Reduce the width of the armature coil in the longitudinal direction of the stator.
Thus, the width of the mover can be reduced. In addition,
When driving by the moving method,
In order to detect the start position and the energization stop position, the coil
To detect the polarity of the magnetic pole at the position facing
When the detection element is provided, the first of any one of the sets,
For the second and third coils, the positional relationship as described above
The first, second and third three magnetic pole detecting elements
The energization start position and energization stop position of each coil of all sets
And the polarity of the magnetic pole at the position facing the coil
Can be detected.

An example of a preferable magnetic flux distribution in the longitudinal direction of the stator formed by the field magnet is a rectangular wave shape. Such a magnetic flux distribution is preferably a perfect rectangle. However, it is difficult to make the magnetic flux distribution a perfect rectangle, and even if it is attempted to make a rectangle, it actually becomes a rectangular wave. Therefore, such a magnetic flux distribution has a rectangular wave shape as close as possible to a perfect rectangle, in other words,
It is preferably a trapezoidal wave shape close to a rectangle. When the magnetic flux distribution has a rectangular waveform as described above, it is possible to suppress the thrust fluctuation of the linear motor.

Further, the total magnetic flux density B _C at each position within the width of the center P _m / 3 of each magnetic pole of the field magnet in the longitudinal direction of the stator, and each of the magnetic poles in the longitudinal direction of the stator. Ratio of magnetic flux density at position B to total B _A
A magnetic flux distribution such that _C / B _A is larger than 0.5 is also preferable. More preferably, the magnetic flux density ratio B _C / B _A is larger than 0.55. Furthermore, the magnetic flux density ratio B _C / B _A is preferably closer to 1. _A magnetic flux distribution in which the magnetic flux density ratio B _C / B _A is larger than 0.7 includes a salient pole-shaped magnetic flux distribution. It is easier to form the field magnet so that the magnetic flux distribution becomes salient poles than to form the field magnet so that the magnetic flux distribution becomes rectangular. Such a magnetic flux density ratio B _C /
When B _A is larger than about 0.7, fluctuation in thrust of the linear motor can be suppressed and high thrust can be generated.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view of an example of a shaft type linear motor according to the present invention, and a part thereof is shown in a cross section. The linear motor LM1 shown in FIG. 1 includes a rod-shaped stator 1 that extends linearly in a predetermined direction, and a movable element 2 that is fitted on the stator.

The stator 1 smoothes the surface of a straight rod-shaped shaft member 10 having a circular cross section made of a machinable and magnetizable material (for example, Fe-Cr-Co-based metal, manganese aluminum (MnAl)). It was formed by processing and magnetized as follows. That is, the shaft member 10
The shaft member 10 is magnetized so as to have a rectangular magnetic flux distribution at an equal pitch as shown in FIG. 2 along the longitudinal direction (longitudinal direction of the stator 1). Thus, a field magnet 11 is formed in which the magnetic poles of the N pole and the S pole are alternately arranged with the same magnetic pole width (length in the longitudinal direction of the stator) along the longitudinal direction of the shaft member 10. Field magnet 11
The width P _m of each magnetic pole in the longitudinal direction of the stator, in other words, the magnetic pole pitch P _m is 30 mm in this example.

The mover 2 includes an armature coil 21 fitted externally to the stator 1, a hollow cylindrical coil support member 23 for supporting the armature coil 21 on the inner peripheral surface, and both ends of the support member 23 where the support member 23 is open. And a bearing 22 that is slidably fitted to the stator 1. The armature 2 can be moved by the bearing 22.
Can move smoothly along the stator 1. Note that the coil supporting member may be made of a ferromagnetic material and have the function of a yoke.

In this example, the armature coil 21 is a ring-shaped U-phase coil L _U , V-phase coil L _V and W-phase coil L _W.
And three coils. These coils are, in this example,
It is formed to a width of 1/3 of the pole pitch P _m respectively. The coils L _U , L _V, and L _W are arranged in the longitudinal direction of the stator 1 in this order, with their center positions shifted by P _m / 3.

With respect to these coils, the positional relationship between the coils and the magnetic poles of the field magnet 11 in the longitudinal direction of the stator is detected, and the positions and the polarities of the magnetic poles of the field magnet 11 to which each coil faces are detected. In order to energize the coil in accordance with
Hall elements h ₁ from the center of _U at a position shifted P _m / 6 on the right side in FIG. 1 is disposed. Similarly, the coil L _V
Is arranged Hall elements h ₂ to P _m / 6 position shifted to the right side in FIG. 1 from the center of which the Hall element h from the center of the coil L _W to a position shifted P _m / 6 on the right side in FIG. 1
₃ are located.

U, V and W in the linear motor LM1
Stator 1 of armature coil 21 composed of three phase coils
Longitudinal width is one pole width P _m of the field magnet 11, with respect to the armature coil width of a conventional shaft type linear motor shown in FIG. 27 2P _n (P _n is pole width), P _m =
_Pn is 1/2, and the mover can be made more compact than before. Even if the width of the bearing is added, the linear motor LM
The width of one mover can be almost half the width of the mover of the conventional linear motor.

When the movable element 2 of the linear motor LM1 described above is driven along the stator 1, the movable element 2 is driven based on the polarity of each magnetic pole of the field magnet 11 detected by the Hall elements h ₁ , h ₂ and h _3. , U, V, and W phases, the center position of each coil in the longitudinal direction of the stator 1 advances in the P _m / 6 drive direction from the upstream end of the magnetic pole of the field magnet 11 in the drive direction in that direction. From the center position to the position further advanced in the 2P _m / 3 drive direction,
In accordance with the polarity of the magnetic pole facing the coil, a constant current flows in a direction in which the coil generates an electromagnetic force in the driving direction.

First, the case where the mover 2 is driven leftward in FIG. 1 will be described. For example, when the U-phase coil L _U is over the magnetic poles of N-pole, the U-phase center position of the coil driving direction of the N pole (left) upstream end in (right end in the drawing) than P _m / between 6 advances to the driving direction position (see FIG. 3 (a)), to further position advanced to 2P _m / 3 drive direction (see FIG. 3 (C)), N of U-phase coil L _U faces
3A and FIG. 3C, the direction in which the electromagnetic force is generated in the driving direction (left direction) with respect to the magnetic poles of the poles. When viewed from the right side,
A constant current is applied to the stator 1 counterclockwise. In addition,
Hereinafter, this energizing direction is referred to as a “+” direction.

The center of this time, the center position of the U-phase coil L _U is in the position advanced to P _m / 6 driving direction from the drive direction (left direction) the upstream end of the N pole, the U-phase coil L _U It is detected by P _m / 6 driving direction upstream Hall elements h _1, which is arranged at a position shifted to the (rear) side from the position. Such position is a position at which the Hall elements h ₁ detects the switching of the magnetic poles to the N pole from the S pole. U-phase coil L _U
But further in advanced position in 2P _m / 3 driving direction is detected by the Hall element h ₃ disposed on the upstream side in the 2P _m / 3 driving directions from the Hall element h _1.
Such position is a position at which the Hall element h ₃ detects the switching of the magnetic poles to the N pole from the S pole. The polarity of the magnetic pole at a position U-phase coil L _U faces are detected by the Hall elements h _1.

[0033] A case where the V-phase coil L _V is over the magnetic poles of N-pole, likewise energizing the coil when driving to the left in FIG. The center position of the V-phase coil L _{V is at} a position advanced in the P _m / 6 driving direction from the upstream end in the driving direction (left direction) of the N pole and at a position further advanced in the 2 P _m / 3 driving direction from that position. it is detected by the Hall elements h ₁ which is disposed in a position shifted P _m with respect to the upstream position in the 2P _m / 3 driving directions from the Hall element h _2, and the Hall element h _2. In the case where the W-phase coil L _W is above the N magnetic poles, the coil is similarly energized when driven leftward in FIG. The center position of the W-phase coil L _W is in the advanced position to the further 2P _m / 3 driving directions from the advanced position and its position P _m / 6 driving direction from the upstream end in the driving direction (left direction) of the N-pole it is detected by the Hall element h ₂ disposed in a position shifted P _m with respect to the upstream position in the 2P _m / 3 driving directions from the Hall element h _3, and the Hall element h _3.

Further, in a case where the U-phase coil L _U is on the pole of the S pole, the same applies when driving to the left in FIG. From the U-phase coil L _U of the central position the driving direction of the S pole (left) position advanced to P _m / 6 driving direction from the upstream end (refer to FIG. 4 (A)), further 2P _m / 3 drive direction position advanced (FIG. 4 (C) see) until, the pole of the S pole U-phase coil L _U faces the direction which generates an electromagnetic force in the driving direction (left direction), i.e., FIG. 4 (B)
As shown in FIGS. 4 (A) and 4 (C), as shown in FIGS.
When viewed from the right side, a constant current is applied to the stator 1 clockwise. Hereinafter, this energizing direction is referred to as a “−” direction. The same applies to the case where the V-phase coil L _V and the W-phase coil L _W are above the magnetic pole of the S pole, and are driven leftward in FIG.

As described above, if the coils of each phase are energized, the polarity of the magnetic pole detected by each Hall element, the energization direction ("+" or "-") and the energization timing of each phase coil are as follows: When the mover 2 is driven in the left direction in FIG. 1, the operation is as shown in FIG. Here, for example, the U-phase coil L _U a "+" try try with sections and is energized in the direction "+" drive direction center position of the N-pole of the U-phase coil L _U which direction the current is started At the position (left direction) advanced from the upstream end in the P _m / 6 driving direction, since the width of the coil is P _m / 3, all parts of the coil are located at positions facing the N pole magnetic pole. Yes, it does not straddle both the N pole and the S pole. The position where the energization of the "+" direction is stopped, i.e. U-phase coil L _U further 2P _m
/ 3 The position advanced in the driving direction, more specifically, the coil L
The center position of _U is P _m / 6 + 2 from the upstream end of the N pole in the driving direction.
Even in position advanced to _{P m / 3 = 5P m /} 6 driving direction, at a position all parts of the coil L _U faces the magnetic poles of N-pole. Therefore, in the section and, thrust coil L _U occurs are all in Figure 1 left, thrust in FIG right does not occur. U-phase coil L _U is "-"
The same applies to the section where power is supplied in the direction.
The same applies to the V-phase coil L _V and the W-phase coil L _W. Therefore, the current supplied to the coils of each phase is not converted into a thrust for driving the mover 2 in the right direction, which is opposite to the left direction in which the mover 2 is to be driven. The conversion is efficient. For the same reason, when the mover 2 moves along the stator 1, there is almost no fluctuation in the thrust.

Therefore, the energization pattern shown in FIG.
For each of the coils of each phase, only when the coil of that phase is located at a position facing one magnetic pole, the coil of that phase is energized in the direction in which thrust is generated to the left in the figure, and the coil of that phase is turned on. No current is supplied while moving between magnetic poles of different polarities. When the coil is energized while moving between magnetic poles of different polarities, the coil portion at the portion facing the magnetic pole of one polarity and the coil portion at the portion facing the magnetic pole of the other polarity are different from each other. Since thrust is generated in the opposite direction, the thrust fluctuation increases.

The energizing method for driving the mover 2 in the left direction in FIG. 1 has been described. However, when the mover 2 is driven rightward in FIG. Similarly, the coils of each phase are energized according to the polarity of the magnetic pole detected by the Hall element. At this time, similarly to when driving to the left, as the Hall element at a position shifted P _m / 6 on the upstream side in the driving direction from the center position of each phase coil is arranged, as shown in FIG. 6 , P behind the driving direction (right direction) from the center of the U-phase coil L _{U m} /
By placing a Hall element h ₄ to 6 shifted position may be energized to each phase coil in the same way as when driving in the left direction. However, in addition to the hall elements h ₁ , h ₂ and h ₃ , the hall element h ₄ is further required, which increases the cost.

[0038] Therefore, in this example, energizes in the same manner as the left direction by using the Hall element h ₃ in the position shifted one pole width P _m from the position of the Hall element h _4. Hall element h ₃
If reversing the polarity of the detection to the magnetic poles of the same polarity of magnetic poles detected by the Hall element h _4, it is possible to perform the same current as when leftward drive. However, when driving in the right direction, when the coil of each phase is on the N pole, the coil is energized in the “−” direction opposite to that when driving in the left direction. Energize in the "+" direction. FIG. 7 shows an energization pattern to each phase coil when the mover 2 is driven rightward in FIG. Even when driving in the right direction, similarly to driving in the left direction, driving can be performed efficiently and thrust fluctuation can be suppressed.

Power is supplied according to the power supply patterns shown in FIGS.
Figure shows an example of an energizing circuit for each phase coil that can perform
FIG. This circuit is a so-called three-phase full-wave drive circuit.
You. In this example, each phase coil L_U, L_VAnd L_WFrom FIG.
Star connection in the winding direction shown in
Jista Q₁~ Q₆A transistor circuit 41 having
Of the magnetic pole detected by the two Hall elements and the driving direction.
Logic circuit 4 that opens and closes the gate of each transistor
2 to energize each phase coil. Note that, in FIG.
The black circle next to the circle indicates the winding direction with respect to the stator 1.
You. Here, as shown in FIG.
When a black circle is drawn on the coil entrance side of the orientation,
Note that current flows through the coil in the “+” direction.
Then, as shown in FIG.
When a black circle is drawn on the exit side,
This indicates that a current flows through the coil. An example
For example, in each section shown in FIG. 5, in the direction shown in FIG.
A current flows through each coil. For example, in the section
Is the transistor Q₁And Q₆Is turned on and the coil L _U
And L_WCurrent is passed through the

The linear motor LM1 shown in FIG.
And the Hall element h₁, H_TwoAnd h _ThreeIs shown below
It may be arranged at a position. As shown in FIG.
Is the X axis direction, the right direction in the figure is the X axis positive direction, U phase
Coil L_UCenter in the stator longitudinal direction (X-axis direction)
Assuming that the position is the position of X = 0, in the example shown in FIG.
Element h₁Is X = P_m/ 6. hole
Element h₁Is apparent from the above description, the position of X
= -P_m/ 6 position. Also, X = P_m/ 6th place
± p · P_m(However, p = 1, 2, 3, ...)
The position may be shifted. If the parameter p is even and
X = P_m/ 6 position Hall element and X = P_m/ 6
± pP_mThe Hall element at the position detects the polarity of the same magnetic pole
I do. When the parameter p is an odd number, X = P_m/ 6th
Hall element and X = P_m/ 6 ± pP_mLocation Hall
X = P in order to detect the magnetic pole of the opposite polarity with the element_m/ 6
+ PP_mInverts the polarity of the magnetic pole detected by the Hall element at the position
If you do, X = P_mDetection of Hall element at / 6 position
The polarity is the same as the polarity of the magnetic pole. Similarly, X = −P_m/ 6
± p · P from position_m(However, p = 1, 2, 3, ...
・) The position may be shifted. Therefore, Hall element
Child h₁Is the U-phase coil L_U± P from center of _m/ 6 ± p
P_m(However, p = 0, 1, 2, 3, ...)
It should just be arranged. Hall element h_TwoAnd h_ThreeSame for
It is like. Hall element h_TwoIs the V-phase coil L_VCenter position of
± P from_m/ 6 ± qP_m(However, q = 0, 1, 2,
3,...). Hall element h_Three
Is the W-phase coil L_W± P from center of_m/ 6 ± rP_m
(Where r = 0, 1, 2, 3, ...)
do it. Note that the parameters p, q, and r increase.
And the Hall element needs to be arranged on the mover 2.
As a result, an extra mover width may be required.

FIG. 12 is a partially omitted schematic side view of another example of the shaft type linear motor according to the present invention. The linear motor LM2 in FIG. 12 is substantially the same as the linear motor LM1 in FIG. 1 except that the width of each phase coil of the armature coil and the arrangement position of the Hall element are different. In FIG. 12, a yoke and a bearing that constitute a mover and support an armature coil are not shown.

Armature coil 21 of linear motor LM2
Are ring-shaped U-phase coils L _U , V
It is composed of three coils, a phase coil L _V and a W-phase coil L _W. In the present example, these coils are each provided with a magnetic pole pitch P
It is formed to have a width of _Pc (< _Pm / 3) smaller than 1/3 of _m . The coils L _U , L _V, and L _W are arranged in the longitudinal direction of the stator 1 in this order, with their center positions shifted by P _m / 3.

For these coils, these coils
Detects the polarity of the magnetic pole of the field magnet 11 facing the
The coil is energized according to the detected magnetic pole polarity, etc.
In the longitudinal direction of the stator 1, the coil L_Uof
P from the center to the right in FIG. _m/ 6
Element h₁Is arranged. Similarly, coil L_Vof
P from the center to the right in FIG._m/ 6
Element h_TwoAre arranged, and the coil L_WCenter position of
To the right in FIG._mHall element shifted by / 6
h_ThreeIs arranged.

[0044] The mover 2 of the linear motor LM2, when driving along the stator 1, as in the case of driving the linear motor LM1, field magnet 11 for detecting the Hall elements h _1, h ₂ and h ₃ Based on the polarity of each magnetic pole of
The U, V and W phase coils are energized. At this time, for each coil, the center position of the coil in the longitudinal direction of the stator 1 is further increased by 2P _m / 2 from the position advanced in the P _m / 6 driving direction from the upstream end of the magnetic pole of the field magnet 11 in the driving direction. Until the position where the coil has advanced in the three driving directions, a constant current in a direction in which the coil generates an electromagnetic force in the driving direction flows according to the polarity of the magnetic pole facing the coil.

When power is supplied in this manner, the linear motor LM
1, each coil has an N pole and an S pole.
Electricity is supplied only when the poles are not straddled, so that thrust is generated only in the drive direction, and the thrust is more efficient and the thrust fluctuation is less. When the width _{Pc of} each coil is _Pc < _Pm / 3, as in the linear motor LM2 in FIG. 12, a Hall element for detecting the polarity of the magnetic pole of the field magnet 11 is provided as shown in FIG. And the coils may be energized as follows.

[0046] In the linear motor LM3 shown in FIG. 13, in the longitudinal direction of the stator 1, a coil L P from the central position on the right side in FIG. 12 of the _{U S (however, P c / 2 ≦ P S} <
P _m / 6) is arranged a Hall element h ₁ at a position shifted, the Hall element h ₁ 'in a position shifted P _S on the left side in FIG. 13 are arranged from the center of the coil L _U. Similarly, there is disposed a Hall element h ₂ from the center of the coil L _V to a position shifted P _S on the right side in FIG. 13, the coil L
Hall element h ₂ 'at a position shifted P _S on the left side in FIG. 13 are arranged from the center of the _V. Hall elements h from the center of the coil L _W to a position shifted P _S on the right side in FIG. 13
₃ is arranged, FIG from the center of the coil L _W 13
A hall element h ₃ ′ is arranged at a position shifted by P _S to the middle left side.

When the mover 2 of the linear motor LM3 is driven along the stator 1, the Hall elements h ₁ , h ₂ ,
Based on the polarities of the magnetic poles of the field magnet 11 detected by h ₃ , h ₁ ′, h ₂ ′, and h ₃ ′, each of the U, V, and W phase coils is applied to the stator 1 longitudinal direction of the coil. central position in is from advanced position to P _S driving direction from the upstream end in the driving direction of the magnetic poles of the field magnet 11,
Further, until the position advances in the 2P _m / 3 driving direction, a constant current in a direction in which the coil generates an electromagnetic force in the driving direction flows according to the polarity of the magnetic pole facing the coil.

When power is supplied in this manner, the linear motor LM
1, each coil has an N pole and an S pole.
Electricity is supplied only when the poles are not straddled, so that thrust is generated only in the drive direction, and the thrust is more efficient and the thrust fluctuation is less. The mover is shown in FIG.
When driving in the middle left, position advanced by P _S from the upstream end center of the U-phase coil L _U is in the driving direction of one magnetic pole, P _S upstream in the driving direction from the center of the coil (rear) can be detected by the Hall elements h ₁ disposed further advanced to 2P _m / 3 driving direction position is detected by the Hall element h ₃ disposed 2P _m / 3 behind the driving direction from the hall elements h ₁ be able to. V
Position advanced P _S from the upstream end in the driving direction of the center one of the magnetic pole phase coil L _V the Hall element h ₂ arranged in P _S rear side in the driving direction from the center of the coil
Can be detected by further proceeds to 2P _m / 3 driving direction position, 2P _m / 3 in the driving direction from the Hall element h ₂
It can be detected by the Hall elements h ₁ which is disposed on the rear side of the position and the P _m shift positions. The position where the center of the W-phase coil L _W is advanced by P _S from the upstream end in the driving direction of one magnetic pole is the Hall element h ₃ arranged on the rear side of P _{S in the} driving direction (left direction) from the center position of the coil. The position further advanced in the 2P _m / 3 driving direction can be detected by h ₂ arranged at a position shifted by P _{m from} the position behind 2P _m / 3 in the driving direction from the Hall element h _3. it can.

In the case of driving in the right direction in FIG. 13, the two positions, that is, the position where the energization is started and the position where the energization is stopped, of the phase coils are determined by the Hall elements h ₁ , h ₂ and h _3.
And the Hall elements h ₁ ′, h ₂ ′ arranged at positions symmetrical with respect to the center position of each phase coil, respectively.
And h ₃ ′, it can be detected in the same way as when driving in the left direction. Note that in the case of driving in the right direction in FIG. 13, the two respective positions of each phase coil can not be detected by the Hall elements h _1, h ₂ and h _3.

In the linear motor LM1 shown in FIG. 1, the three phase coils constituting the armature coil are arranged such that their center positions are shifted by P _m / 3 in the longitudinal direction of the stator. The coil of ± n · P _m (n = 1, 2, 3,.
・ ・) It may be shifted. It should be noted that, of the coils shown in FIG.
When the coils are shifted from the position shown in FIG.

[0051] For example, as shown in FIG. 14, a V-phase coil of the linear motor LM1 shown in FIG. 1 may be shifted one pole width P _m. The linear motor LM4 shown in FIG. 14 is substantially the same as the linear motor LM1 of FIG. The linear motor LM4 is a linear motor LM.
The U-phase coil and W-phase coil in 1 may be viewed as shifted P _m respectively. Components having substantially the same functions as those of the linear motor shown in FIG. 1 are denoted by the same reference numerals as those in FIG.

Armature coil 21 of linear motor LM4
Are ring-shaped U-phase coils L _U , V
It is composed of three coils, a phase coil L _V and a W-phase coil L _W. In the present example, these coils are each provided with a magnetic pole pitch P
It is formed with a width of 1/3 of _m . The coils L _U , L _W, and L _V are arranged such that their center positions are shifted by 2P _m / 3 in the longitudinal direction of the stator 1 in this order.

For these coils, as in the case of the linear motor LM1 in FIG.
Hall elements h ₁ from the center of the coil L _U at positions shifted P _m / 6 on the right side in FIG. 14 are arranged. Similarly,
There is disposed a Hall element h ₂ from the center of the coil L _V to a position shifted P _m / 6 on the right side in FIG. 14, the coil L
_W Hall element h ₃ at a position shifted P _m / 6 on the right side in FIG. 14 are arranged from the center of the.

This linear motor LM4 is also a linear motor
Driving the mover 2 along the stator 1 in the same manner as LM1
can do. That is, the Hall element h₁, H_TwoPassing
H _ThreeTo the polarity of each magnetic pole of the field magnet 11
Based on the U, V and W phase coils, respectively.
The center position of the coil in the longitudinal direction of the stator 1 is
From the upstream end of the magnetic pole of the gnet 11 in the mover driving direction.
R_m/ 6P from the position advanced in the / 6 drive direction_m/
(3) Until the position where the coil has advanced in the drive direction,
Depending on the polarity of the magnetic pole, the coil
A constant current in the direction in which Energize like this
As a result, like the linear motor LM1, the linear motor L
M4 drives efficiently and suppresses thrust fluctuation
be able to.

Move the linear motor LM4 leftward in FIG.
When driving, the detection magnetic pole of each Hall element and the phase coil
Fig. 15 shows the relationship between the power supply direction and power supply timing.
Show. The leftward movement of the linear motor LM4 shown in FIG.
The electric pattern is the leftward direction of the linear motor LM1 shown in FIG.
The V-phase coil is set to P _m
The polarities of the opposing magnetic poles have been reversed due to the displacement.
It is assumed that the direction of energization to the V-phase coil is reversed.
Can also.

The linear motor LM1 and the like shown in FIG. 1 described above have only one set of three armature coil groups of U-phase, V-phase and W-phase coils. May be provided in plural sets. FIG.
FIG. 7 shows a shaft type linear motor LM5 according to the present invention having an armature coil including three coil groups.

The stator 1 has a field magnet 11 similar to that shown in FIG. 1, and the shaft member 10 on which the field magnet 11 is formed is further provided with position detection, speed detection, position control, An encoder chart 31 forming a part of an encoder for speed control or the like is formed. The encoder chart 31 is of a magnetic type in this example, and the field magnets 11 are arranged such that N poles and S poles are alternately arranged at equal pitches in the longitudinal direction of the shaft member 10.
It is magnetized by being superimposed on it. The magnetic poles of the N pole and the S pole of the encoder chart 31 are arranged at a pitch of 100 μm in this example.

The mover 20 includes an armature coil 210 fitted externally to the stator 1, a hollow cylindrical coil support member 230 supporting the armature coil 210 on its inner peripheral surface, and a bearing 2.
Two. On the mover 2, a magnetic sensor 32 (a sensor composed of a magnetoresistive element called an MR element) is provided at a position facing the encoder chart 31.
Are supported and arranged on the inner peripheral surface of the armature coil 210, and the chart 3 and the sensor 32 provide the encoder 3. In the present example, the magnetic encoder chart 31 is formed so as to be superimposed on the field magnet 11. Is also good. Also in this case, the magnetic sensor 32 is arranged on the mover 2 so as to face the chart 31. The encoder may be an optical encoder instead of the magnetic encoder. The optical encoder chart is, for example, the stator 1 or the stator 1
It may be formed on a member arranged in parallel with. When the encoder chart is of an optical type, the sensor (for example, a sensor including a light emitting element and a light receiving element) is arranged on the mover 2 so as to face the encoder chart.

In this embodiment, the armature coils 210 are U, V
And three coil groups with three coils of W phase as one set
The first set of coil groups, the second set of coil groups,
Are arranged in the longitudinal direction of the stator in the order of the coil groups.
You. The first group of coils is a coil L_U1, L_V1And L_W1Or
And are arranged in this order in the longitudinal direction of the stator. No.
The two coil groups are coil L_U2, L_V2And L_W2From
In this order, they are arranged in the longitudinal direction of the stator. Third group
Coil group is L_U3, L_V3And L_W3And in this order
The stator is arranged in the longitudinal direction. Any carp of any pair
Are also externally fitted to the stator 1. In this example,
Pitch P_mIs formed to have a width of 1/3 of the width. Any pair
The center position of each coil is also P_mOffset by 3
Is placed. Also, two adjacent coils of different sets,
That is, the coil L_W1And coil L_U2, And coil L_W2When
Coil L_U3In this example, the center position is P_m/ 3
It is arranged. Therefore, these nine carp
All have a center position P _mDisplaced by / 3
Have been.

[0060] To drive the linear motor LM5 similar to the above, in the longitudinal direction of the stator 1, arranged Hall elements h ₁ from the center of the coil L _U1 at a position shifted P _m / 6 on the right side in FIG. 16 Have been. Similarly, there is disposed a Hall element h ₂ at a position shifted P _m / 6 on the right side in FIG. 16 from the center of the coil L _V1, P _m / 6 shifted from the center of the coil L _W1 in the right side in FIG. 16 Hall elements h ₃ are arranged in positions.

When the mover 20 of the linear motor LM5 is driven along the stator 1, the Hall elements h ₁ , h ₂
Based on the polarity of each magnetic pole of the field magnet 11 detected by h ₃ and h _3, the center position of each coil in each set and each phase coil in the longitudinal direction of the stator 1 is determined by the movable element driving of the magnetic pole of the field magnet 11. P from the upstream end in the direction _m /
6 From the position advanced in the driving direction to the position further advanced in the 2P _m / 3 driving direction, the direction in which the coil generates an electromagnetic force in the driving direction is constant according to the polarity of the magnetic pole facing the coil. Apply current.

Here, the detection of the energization start position and the energization stop position to the first set of phase coils and the energization depend on the positional relationship between the phase coils and the Hall elements in the linear motor LM1. Since the positional relationship between each coil of the first set and each Hall element in LM5 is the same as that of motor LM1, it can be performed. The positional relationship between the second set of each phase coil and each Hall element in the linear motor LM5 is as described with reference to FIG. since the Hall elements can be seen to those staggered P _m, the detection of the energization start position and the energization stopping position to the second set of phase coils is performed by these Hall elements. Similarly, detection of the energization start position and energization stop position for the third set of coils in the linear motor LM5 can be performed by these Hall elements. FIG. 17 shows an energization pattern for each coil when the linear motor LM5 is driven, for example, to the left in FIG. When the power is supplied in this manner, the linear motor LM5 can be driven efficiently and with little fluctuation in thrust, similarly to the linear motor LM1. Since the linear motor LM5 has three sets of coil groups including three coils, the linear motor LM1
, The generated thrust can be increased.

The energization to each coil in the energization pattern shown in FIG. 17 is performed for each coil group of each group.
Even if the energizing circuit shown in FIG. In this case, three sets of energizing circuits (driving circuits) are required. However, a single energizing circuit can be formed as follows. In the linear motor LM5, since the nine coils are arranged in the above-described positional relationship, the U-phase coils of each set, that is, the coils L _U1 , L _U2 , and L _U3 each have a center position P in the longitudinal direction of the stator. It is shifted by _m . V of each set
The same applies to the phase coil and the W-phase coil. Thereby, as shown in FIG. 17, the energization start position, the energization stop position, and the energization direction are the same for the coils L _U1 and L _U3, and for the coil L _U2 , the energization start position, The energization stop position is the same and only the energization direction is reversed. The same applies to the V-phase coil and the W-phase coil of each set. Therefore, if each set of U-phase coils, each set of V-phase coils and W-phase coils are connected in parallel in the winding direction shown in FIG. 18 and star-connected, only one energizing circuit shown in FIG. 17 can be energized in the energization pattern shown in FIG. The winding direction of each coil shown in FIG. 18 is, for example, the winding direction of the coil L _U2 (L _V2 , L _W2 ) for reversing the energization direction for each set of U-phase (V-phase, W-phase) coils. _Is reversed from the other coils L _U1 and L _U3 (L _V1 and L _V3 , L _W1 and L _W3 ).

Here, an example will be described in which the encoder provided on the linear motor LM5 is used to drive the motor under PLL control (phase synchronization control). FIG. 19 shows a schematic block diagram of an example of such a linear motor operation control circuit together with the coils of each phase. In FIG. 19, the term "U-phase coil" refers to three coils L _U1 , L _U2 , and L _U3 connected in parallel as shown in FIG. Similarly, a V-phase coil refers to three coils L _V1 , L _V2 , and L _V3 connected in parallel, and a W-phase coil refers to three coils L _W1 , connected in parallel.
L _W2 and L _W3 .

The operation control circuit shown in FIG. 19 has a computer 61 for outputting a reference clock signal having a frequency corresponding to the target speed of the linear motor mover 20. Control circuit) 6
2 is input. The PLL control circuit unit 62 further includes:
A signal indicating the actual moving speed of the mover 20 is fed back from the encoder 3. The encoder 3 includes the encoder chart 31 and the magnetic sensor 32 described above. In the PLL control circuit section 62, a signal corresponding to the phase difference between the reference clock signal from the computer 61 and the moving speed signal from the encoder 3 is output to the compensation circuit section 63. In the compensating circuit 63, lead / lag compensation of the transmission system is performed, and a signal corresponding to the phase difference between the compensated reference clock signal and the moving speed signal is input to the energization control circuit 64.

The energization control circuit section 64 generates a current corresponding to a signal corresponding to the phase difference between the reference clock signal and the moving speed signal, and determines the current based on the polarity of the magnetic pole of each coil detected by the Hall element. Power is supplied in the above-described power supply pattern. As a result, a current that matches the phases of the reference clock signal corresponding to the target speed and the signal corresponding to the actual moving speed of the mover 20 flows through the coils of each phase. At the desired speed.

FIG. 20 shows an example of such an operation control circuit. The operation control circuit of FIG. 20 is a motor drive IC including the above-described PLL control circuit unit 62 and compensation circuit unit 63.
(LB1823) (manufactured by Sanyo Electric Co., Ltd.). The motor drive IC also performs the function of the logic circuit 42 shown in FIG. Note that if an encoder is provided in the linear motor LM1 or the like in FIG.
The operation can be controlled by the L control method.

In the above example, in order to facilitate understanding,
The magnetic field formed by the field magnet 11 was a perfect rectangle shown in FIG. 2 along the longitudinal direction of the stator. With such a magnetic flux distribution, according to the energization method described above,
As described above, there is almost no change in thrust. However,
Actually, the polarity of the magnetic pole cannot be changed steeply like the rectangular wave shown in FIG. 2; in fact, the polarity of the magnetic pole changes gradually, and the magnetic flux distribution along the longitudinal direction of the stator has a rectangular wave shape. In other words, a trapezoidal wave shape results. Therefore,
The thrust generated by the linear motor fluctuates due to the change in the magnetic flux density. In the conventional linear motor shown in FIG. 27 as well, when the magnetic flux distribution has a trapezoidal wave shape, a thrust variation similarly occurs due to a change in the magnetic flux density.

The magnetic flux distribution in the longitudinal direction of the stator formed on the field magnet of the linear motor according to the present invention may be rectangular. When the linear motor according to the present invention is driven by the above-described driving method, there is no coil portion that generates a thrust in a direction opposite to the driving direction as in a conventional linear motor. it can. For example, as the magnetic flux distribution in the longitudinal direction of the stator formed by the field magnet has a rectangular wave shape closer to a rectangular shape as shown in FIG.

To increase the thrust generated by the linear motor, the magnetic flux density of the magnetic field formed by the field magnet may be increased. For example, the magnetic flux distribution in the stator longitudinal direction of the magnetic field formed by the field magnet, when a rectangular wave as shown in FIG. 21, may be increased magnetic flux density B _max of the upper base portion. When magnetizing the shaft member so that the field magnet has the above-described magnetic flux distribution along the stator longitudinal direction, for example, the following is performed. That is, as shown in FIG. 22, coils L ₁ , L ₂ , L ₃ , L ₄ ,... Wound at equal intervals in the opposite direction are arranged in the longitudinal direction of the magnetizable shaft member 10. The coils adjacent to each of these coils are energized and magnetized so that currents in opposite directions flow. In the case of magnetizing in this manner, the maximum magnetic flux density to be magnetized is increased by increasing the magnitude of the current flowing through each coil. The maximum value of the magnetized magnetic flux density depends on the ratio between the diameter of the shaft member and the magnetized pitch and the shape of the magnetized magnetic flux distribution.

However, in the case of energizing and magnetizing as shown in FIG. 22, when energizing current is increased to increase the maximum magnetic flux density to be magnetized, as shown in FIG. In the magnetic flux distribution in the above, the shape is separated from the rectangle in the order of M-shape → trapezoidal wave → sine wave → triangle wave → salient pole in order of the smallest magnetic flux density. If the magnetic flux distribution in the longitudinal direction of the stator is, for example, sinusoidal, the generated thrust increases in a certain section, but the thrust fluctuation also increases as a whole.

When the above-described linear motor LM1 of FIG. 1 is driven by the above-described energizing method,
The center P of the magnetic pole of the field magnet in the longitudinal direction of the stator.
The magnetic field having a width of _m / 3 acts on the coil that is always energized, and always contributes to the generation of thrust. Therefore, as shown in FIG. 24, the linear motor LM1 has been described above even if the magnetic field is present only in the central P _m / 3 width portion and the magnetic field in other portions is zero. When driving by the energization method, there is no change in thrust.

Also in this case, it is not possible to magnetize the magnetic flux distribution so as to be a perfect rectangle as shown in FIG. But,
If the shape is close to the magnetic flux distribution shown in FIG. 24, the thrust fluctuation can be reduced accordingly. In other words, the total magnetic flux density B _C at each position within the width of the center P _m / 3 in the stator longitudinal direction of each magnetic pole, and the magnetic flux density at each position in the stator longitudinal direction of one of the magnetic poles B _C / B with the total B _A
The larger the _A is, and the smaller the variation ΔB _b of the magnetic flux density in the width of 2P _m / 3 in the longitudinal direction of the stator of the magnetic pole is, the smaller the thrust variation can be. As shown in FIG. 25, assuming that the stator longitudinal direction is the x direction, the magnetic flux density at each position in the stator longitudinal direction is B (x), and the x direction position of the end of the magnetic pole is x = 0, Center of magnetic pole P _m /
The total magnetic flux density B _C at each position within the width 3 and the total magnetic flux density B _A at each position of one magnetic pole can be expressed as follows. Further, the variation ΔB _{b of the} magnetic flux density can be expressed as follows.

[0074]

(Equation 1)

[0075]

(Equation 2)

[0076]

(Equation 3)

However,

[0078]

(Equation 4)

When the magnetic flux distribution is a perfect sine wave,
Magnetic flux density ratio B_C/ B_AIs 0.5, as shown in FIG.
In the case of magnetic flux distribution, the above magnetic flux density ratio B_C/ B_AIs 1
You. FIG. 26 shows a magnetic flux distribution close to the magnetic flux distribution of FIG.
The salient pole-shaped magnetic flux distribution shown in FIG. For example,
The diameter of the shaft member to be magnetized is 16 mm, and the magnetization pitch is
When making the distribution of the magnetic flux a salient pole,
Is the magnetic flux density ratio B _C/ B_ASo that exceeds 0.7
It can be magnetized. At this time, the thrust fluctuation is about one digit%
It is suppressed every time. Magnetic flux distribution trapezoidal on the same shaft member
When magnetizing so that the magnetic flux density ratio B_C/
B_AIs about 0.4 or less, and the thrust fluctuation at this time is 1
It is about 5%. Figure shows the magnetic flux distribution in the longitudinal direction of the stator.
Magnetizing to form a salient pole as shown in FIG.
As shown in FIG.
Wear. Moreover, if the magnetic flux distribution is made salient, the magnetic flux distribution
The maximum magnetic flux compared to the case of a rectangular wave shape close to a rectangle
The density can be increased and the generated thrust can be increased.
You.

Therefore, when the magnetic flux distribution is formed as a salient pole as shown in FIG.
The generated thrust can be increased. Moreover, it is easier to magnetize the magnetic flux distribution so as to be a salient pole than in the case where the magnetic flux distribution is magnetized so as to have a rectangular wave shape close to a rectangle. When the magnetic flux distribution is magnetized in a trapezoidal wave shape close to a rectangle, a magnetizing yoke must be provided to manage many parameters and magnetize.

[0081]

According to the present invention, there is provided a rod-shaped stator having a field magnet in which N poles and S poles are alternately arranged, and an armature coil externally fitted to the stator. The present invention provides a shaft-type linear motor including a movable element that can reciprocate along the arm, and that can reduce thrust fluctuation and can be driven efficiently.

According to the present invention, there is provided such a linear motor, wherein the width of the mover in the longitudinal direction of the stator is substantially equal to the conventional width.
It is possible to provide a shaft type linear motor that can be reduced to about / 2. Further, according to the present invention, it is possible to provide a driving method for a shaft type linear motor which is a driving method for such a linear motor, which has a small thrust fluctuation and can be driven efficiently.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional schematic side view of an example of a shaft type linear motor according to the present invention.

FIG. 2 is a diagram showing an example of a magnetic flux distribution formed by a field magnet of the linear motor shown in FIG.

FIGS. 3A and 3C show a state in which the U-phase coil of the linear motor shown in FIG. 1 is moving on the N pole to the left in the figure, and FIGS. (D) shows the direction of current supply to the U-phase coil at this time.

FIGS. 4A and 4C show how the U-phase coil of the linear motor shown in FIG. 1 moves on the S pole to the left in the figure. (D) shows the direction of current supply to the U-phase coil at this time.

FIG. 5 is a diagram showing the relationship between the detected magnetic pole polarity of each Hall element and the energizing timing and energizing direction to each phase coil when the mover of the linear motor in FIG. 1 is driven leftward in FIG. It is.

FIG. 6 is a diagram showing another example of the arrangement position of the Hall element in the linear motor shown in FIG. 1;

FIG. 7 is a diagram showing the relationship between the detected magnetic pole polarity of each Hall element and the energizing timing and energizing direction to each phase coil when the mover of the linear motor in FIG. 1 is driven rightward in FIG. It is.

8 is a diagram showing an example of an energizing circuit that can energize each phase coil in the energizing patterns shown in FIGS. 5 and 7. FIG.

FIGS. 9A and 9B are diagrams for explaining a difference in a coil winding direction.

FIG. 10 is a diagram showing a direction of energization to each coil in each section shown in FIG. 5;

11 is a diagram showing still another example of the arrangement position of the Hall element in the linear motor shown in FIG.

FIG. 12 is a partially omitted sectional view showing another example of the shaft type linear motor according to the present invention.

13 is a diagram showing another example of the arrangement position of the Hall element in the linear motor shown in FIG.

FIG. 14 is a schematic partial cross-sectional side view showing still another example of the shaft type linear motor according to the present invention.

FIG. 15 is a diagram showing the relationship between the detected magnetic pole polarity of each Hall element and the energization timing and energization direction to each phase coil when the mover of the linear motor in FIG. 14 is driven in the left direction in FIG. It is.

FIG. 16 is a partial cross-sectional schematic side view showing still another example of the shaft type linear motor according to the present invention.

17 is a diagram showing the relationship between the detected magnetic pole polarity of each Hall element and the energizing timing and energizing direction to each phase coil when the mover of the linear motor in FIG. 16 is driven leftward in FIG. It is.

FIG. 18 is a diagram illustrating an example of a connection state of each coil of the linear motor in FIG. 16;

FIG. 19 is a schematic block diagram of an example of an operation control circuit of the linear motor in FIG. 16;

20 is an example of an operation control circuit of the linear motor in FIG.

FIG. 21 is a diagram showing another example of the magnetic flux distribution formed by the field magnet.

FIG. 22 is a diagram showing a state when magnetizing a shaft member.

FIG. 23 is a diagram showing still another example of the magnetic flux distribution formed by the field magnet.

FIG. 24 is a diagram showing an example of an ideal magnetic flux distribution formed by a field magnet.

FIG. 25 is a diagram showing still another example of the magnetic flux distribution formed by the field magnet.

FIG. 26 is a diagram showing still another example of the magnetic flux distribution formed by the field magnet.

27A and 27B are schematic side views of an example of a conventional shaft type linear motor.

FIG. 28 is a diagram showing the relationship between the detected magnetic pole polarity of each Hall element and the energization timing and energization direction to each phase coil when the mover of the linear motor in FIG. 27 is driven leftward in FIG. It is.

[Explanation of symbols]

LM1, LM2, LM3, LM4, LM5 linear motor 1 stator 11 field magnet 2 armature 21, 210 armature coils _{L U, L V, L W} , L U1, L V1, L W1, L U2, L V2 , L
_{W2, L U3, L V3,} L W3 coil 22 bearing 23, 230 coil support member 3 Encoder 31 The encoder chart 32 encoder sensor _{h 1, h 2, h 3} , h 1 ', h 2', h 3 ' Hall element (Magnetic pole detection element)

Claims (17)

[Claims] And wherein 1, further comprising a field magnet in which the magnetic poles of the S pole are arranged alternately in a predetermined width P _m of the N pole of the magnetic pole and the width P _m, rod-like stator extending in the predetermined direction, An armature coil externally fitted to the stator, and a mover reciprocally movable along the stator, wherein the armature coil satisfies the following conditions (A) and (B): A shaft type linear motor comprising one or more sets of coils each including one, two, and three coils. (A) The first coil, the second coil, and the third coil have the same width in the longitudinal direction of the stator, and the width P _c is P
_c ≦ P _m / 3. (B) The center position of the second coil in the longitudinal direction of the stator is P _m / 3 + j · from the center position of the first coil in the longitudinal direction of the stator in any one direction in the longitudinal direction of the stator. P _m (j is an integer), and the center position of the third coil in the stator longitudinal direction is different from the center position of the first coil in the stator longitudinal direction in the stator longitudinal direction. in one _{direction, 2P m / 3 + k ·} P m (k is an integer) shifted in position. 2. In at least one set of coils,
P _m / 6 + p · P from the center position of the first coil in the longitudinal direction of the stator in any one direction in the direction.
_a first magnetic pole detection element, which is disposed on the mover at a position shifted by _m (p is an integer), and is capable of detecting the polarity of a magnetic pole of the field magnet; and a length of the stator of the second coil. P _m / 6 + q · P from the center position in the direction to the one direction in the direction.
_a second magnetic pole detection element, which is disposed on the mover at a position shifted by _m (q is an integer) and is capable of detecting the polarity of the magnetic pole of the field magnet; and the length of the stator of the third coil. P _m / 6 + r · P from the center position in the direction to the one direction in the direction.
The shaft type linear device according to claim 1, further comprising: a third magnetic pole detecting element disposed on the mover at a position shifted by _m (r is an integer) and capable of detecting the polarity of the magnetic pole of the field magnet. motor. 3. In at least one set of coils,
Center position of the first coil in the stator longitudinal direction
From any one of the directions P_S+ P₁・ P_m
(P ₁Is an integer. P_c/ 2 ≦ P_S≤P_m/ 6) Offset position
The magnetic field of the field magnet, which is arranged on the mover,
First magnetic pole detection element capable of detecting the polarity of a pole
And a center position of the first coil in the stator longitudinal direction.
From P in the direction opposite to the one direction in this direction._S+ P_Two
・ P_m(P_Two(Integer) placed on the mover at a shifted position
The detected polarity of the magnetic pole of the field magnet is detected.
And a center position of the second coil in the longitudinal direction of the stator.
From the direction P_S+ Q₁・ P_m(Q
₁Is an integer).
The polarity of the magnetic pole of the field magnet can be detected.
A third magnetic pole detecting element, and a center position of the second coil in the stator longitudinal direction.
From P in the direction opposite to the one direction in this direction._S+ Q_Two
・ P_m(Q_Two(Integer) placed on the mover at a shifted position
The detected polarity of the magnetic pole of the field magnet is detected.
A fourth magnetic pole detection element, and a center position of the third coil in the stator longitudinal direction.
From the direction P_S+ R₁・ P_m(R
₁Is an integer).
The polarity of the magnetic pole of the field magnet can be detected.
A fifth magnetic pole detection element, and a center position of the third coil in the stator longitudinal direction.
From P in the direction opposite to the one direction in this direction._S+ R_Two
・ P_m(R_Two(Integer) placed on the mover at a shifted position
The detected polarity of the magnetic pole of the field magnet is detected.
And a sixth magnetic pole detection element capable of:
Shaft type linear motor. 4. A shaft type linear motor according to claim 2, wherein said magnetic pole detecting element is a Hall element. 5. A magnetic flux distribution in a longitudinal direction of the stator formed by the field magnet has a rectangular wave shape.
5. The shaft type linear motor according to any one of items 1 to 4. 6. A total B _C of the magnetic flux density at each position in the width of the central P _m / 3 in the lengthwise direction of the stator magnetic poles of the field magnet, each of the stator longitudinal direction of the pole Ratio of the magnetic flux density at the position to the total B _A , B _C / B
5. The shaft type linear motor according to claim 1, wherein _A is larger than 0.5. 7. The method for driving a shaft-type linear motor according to claim 1, wherein the fixed coil is fixed to each of the first coil, the second coil, and the third coil. The center position of the magnetic pole of the field magnet is P _m /
6 From the position advanced in the drive direction to the position further advanced in the 2P _m / 3 drive direction, the direction in which the coil generates an electromagnetic force in the drive direction is constant according to the polarity of the magnetic pole facing the coil. A method of driving a shaft type linear motor, characterized by flowing an electric current. 8. The method of driving a shaft-type linear motor according to claim 1, wherein the fixing of the coils to the first coil, the second coil, and the third coil, respectively. The center position in the armature longitudinal direction is P from the upstream end of the magnetic pole of the field magnet in the mover driving direction in the stator longitudinal direction.
From _{S (P c / 2 ≦ P} S ≦ P m / 6) proceeds in the driving direction position, further until position advanced to 2P _m / 3 drive direction, depending on the polarity of the magnetic poles that coil is opposed, A method of driving a shaft type linear motor, characterized in that a constant current in a direction in which the coil generates an electromagnetic force in a driving direction flows. 9. have field magnet where the magnetic pole of the S pole are arranged alternately in a predetermined width P _m of the N pole of the magnetic pole and the width P _m, and the rod-shaped stator extending in the predetermined direction, An armature coil externally fitted to the stator; and a mover reciprocally movable along the stator. The armature coil includes first, second and third coils. One or more sets of coil groups are provided,
Said first, second and third coils, said stator longitudinal width are the same, a width P _c is P _c ≦ P _m / 3, the stator longitudinal center position P _m A shaft type linear motor, wherein the shaft type linear motor is arranged at a position shifted by / 3. 10. The armature coil includes a plurality of coil groups each including the first, second, and third coils as a set, and each of the armature coils is disposed at a position adjacent to each other in each adjacent set. The center position of the two coils in the stator longitudinal direction is
10. The shaft type linear motor according to claim 9, wherein each of them is shifted by _Pm / 3. 11. With respect to at least one set of coil groups, P _m / 6 + p · P from a center position of the first coil in the longitudinal direction of the stator in one direction in the direction.
_a first magnetic pole detection element disposed on the mover at a position shifted by _m (p is an integer) and capable of detecting the polarity of the magnetic pole of the field magnet; The field magnet of the field magnet, which is arranged on the mover at a position shifted from the center position of the second coil in the stator longitudinal direction in the one direction in the direction by P _m / 6 + q · P _m (q is an integer). A second magnetic pole detecting element capable of detecting the polarity of a magnetic pole; and _Pm / 6 + r in one direction from the center position of the third coil in the one set of coil groups in the longitudinal direction of the stator. 11. A third magnetic pole detecting element, which is disposed on the mover at a position shifted by P _m (r is an integer) and is capable of detecting the polarity of the magnetic pole of the field magnet. Shaft type Near motor. 12. At least one set of coil groups
And the center of the first coil in the stator longitudinal direction.
P from the position in any one of the directions_S+ P₁・
P_m(P ₁Is an integer. P_c/ 2 ≦ P_S≤P_m/ 6) shifted
The field magnet arranged on the mover at a position
Magnetic pole detecting element capable of detecting the polarity of the magnetic pole of the first magnetic pole
And a center position of the first coil in the stator longitudinal direction.
From P in the direction opposite to the one direction in this direction._S+ P_Two
・ P_m(P_Two(Integer) placed on the mover at a shifted position
The detected polarity of the magnetic pole of the field magnet is detected.
And a center position of the second coil in the longitudinal direction of the stator.
From the direction P_S+ Q₁・ P_m(Q
₁Is an integer).
The polarity of the magnetic pole of the field magnet can be detected.
A third magnetic pole detecting element, and a center position of the second coil in the stator longitudinal direction.
From P in the direction opposite to the one direction in this direction._S+ Q_Two
・ P_m(Q_Two(Integer) placed on the mover at a shifted position
The detected polarity of the magnetic pole of the field magnet is detected.
A fourth magnetic pole detection element, and a center position of the third coil in the stator longitudinal direction.
From the direction P_S+ R₁・ P_m(R
₁Is an integer).
The polarity of the magnetic pole of the field magnet can be detected.
A fifth magnetic pole detection element, and a center position of the third coil in the stator longitudinal direction.
From P in the direction opposite to the one direction in this direction._S+ R_Two
・ P_m(R_Two(Integer) placed on the mover at a shifted position
The detected polarity of the magnetic pole of the field magnet is detected.
And a sixth magnetic pole detection element capable of:
10. The shaft type linear motor according to 10. 13. A shaft type linear motor according to claim 11, wherein said magnetic pole detecting element is a Hall element. 14. The shaft-type linear motor according to claim 9, wherein a magnetic flux distribution in the longitudinal direction of the stator formed by the field magnet has a rectangular wave shape. 15. A total magnetic flux density B _C at each position within a width of the center P _m / 3 of each magnetic pole of the field magnet in the stator longitudinal direction, and each of the magnetic poles in the stator longitudinal direction. Ratio of the magnetic flux density at the position to the total B _A , B _C /
14. The shaft type linear motor according to claim 9, wherein B _A is larger than 0.5. 16. The method of driving a shaft type linear motor according to claim 9, wherein each of the first coil, the second coil, and the third coil in each of the coil groups of each set is provided. , the center position in the lengthwise direction of the stator of the coil respectively, from position advanced to P _m / 6 driving direction from the upstream end in the moving element driving direction in the stator longitudinal direction of the magnetic poles of the field magnet, further 2P _m / 3 To the position advanced in the driving direction,
A driving method for a shaft type linear motor, characterized in that a constant current in a direction in which the coil generates an electromagnetic force flows in a driving direction according to the polarity of a magnetic pole facing the coil. 17. The driving method for a shaft type linear motor according to claim 9, wherein the fixed coil is fixed to each of the first coil, the second coil, and the third coil. The center position in the stator longitudinal direction is P from the upstream end of the magnetic pole of the field magnet in the mover driving direction in the stator longitudinal direction.
From _{S (P c / 2 ≦ P} S ≦ P m / 6) proceeds in the driving direction position, further until position advanced to 2P _m / 3 drive direction, depending on the polarity of the magnetic poles that coil is opposed, A method of driving a shaft type linear motor, characterized in that a constant current in a direction in which the coil generates an electromagnetic force in a driving direction flows.