JPH07154956A - Polyphase and multipolar linear motor - Google Patents

Abstract

PURPOSE:To make the mutual interference characteristic of all current phases equal and to sufficiently reduce a propulsive-force ripple by a method wherein effective conductor parts at end parts of armature coil groups are set so as to be the same in number regarding their current phases. CONSTITUTION:A linear DC motor 1 is constituted of a stator 2 and of a mover 7 which is arranged so as to be movable in the length direction of the stator 2. The stator 2 is provided with a lower-part holder 3 and an upper-part holder 4 which are arranged in parallel so as to be separated from each other at the upper part and the lower part, and both holders 3, 4 are arranged so as to be of different polarities in positions in which field magnets 5, 6 in which different polarities are arranged alternately are faced with each other in their length direction. Thereby, a propulsive force is generated in a second magnetic- substance arrangement with reference to a first magnetic-substance arrangement. At this time, since effective conductors parts at end parts of armature coil groups are set so as to be the same in number regarding their current phases, a difference in a mutual intereference characteristic is reduced, and a propulsive- force ripple can be reduced sufficiently by a simple constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor,
In particular, a multi-phase multi-phase arrangement including a first magnetic body array in which different magnetic poles are alternately arranged along the moving direction and a second magnetic body array having a plurality of armature coil groups arranged along the moving direction Pole type linear motor.

[0002]

2. Description of the Related Art As an example of a linear motor, there is a multi-pole type linear DC motor shown in "Linear motor and its application" (ed. It can be used for precision positioning and driving of a precision feed stage in FPD manufacturing equipment, printed circuit board manufacturing equipment, and the like.

This multi-pole type linear DC motor has a first magnetic body array consisting of a group of permanent magnets in which different magnetic poles are alternately arranged along the moving direction, and a large number of armature coils arranged along the moving direction. And a second magnetic material array having the same. The armature coil of the second magnetic body array is controlled by a multi-phase current, and a thrust in one direction is generated by controlling the current while detecting the relative position of the magnetic pole and the coil.

In such a multi-pole / multi-phase type linear DC motor, when a coil crosses between different magnetic poles, a variation in thrust called a thrust ripple occurs. Therefore, it is necessary to smooth this. As a method for smoothing the thrust ripple, the above-mentioned document shows that a thrust correction coefficient corresponding to the coil position is obtained in advance, stored in the ROM of the current control unit, read during operation, and superposed on the coil current. ing.

However, in that configuration, in order to improve the correction accuracy, it is necessary to obtain data by actual measurement while changing the position of the coil, which involves complicated work. In addition, it is necessary to create correction data based on the data obtained by the measurement and store it in ROM. Furthermore, since it is necessary to control the reading of the correction data based on the position information, the control device becomes complicated. Moreover, it is impossible to completely correct the thrust fluctuation with the actual measurement data.

By the way, in the field of servo motors, as a structure for reducing the thrust ripple, a structure has been adopted in which the back electromotive force waveform caused by each current phase is approximated to a sine wave.
How to use "54-56: Akira Kawamura, Comprehensive Electronic Publishing). If the sinusoidal back electromotive force generated for each current phase is superimposed, the thrust ripples are canceled and reduced.

Therefore, the inventor of the present application considered applying this configuration to the field of linear motors. However, unlike a normal motor that has an endless structure in the direction of rotation,
In the case of a linear motor having both ends, it is not enough to bring the back electromotive force waveform of each current phase close to a sine wave. For example, when a multi-phase linear motor having three or more phases is simply constructed by continuously arranging a plurality of rectangular frame-shaped armature coils, it is assumed that one of the current phases is located at both ends of the armature. They cannot be located, and the mutual interference characteristics of all current phases cannot be made the same. If there is a difference in the mutual interference characteristics between the current phases, thrust ripple correction cannot be performed sufficiently.

An object of the present invention is to sufficiently reduce the thrust ripple with a simple structure.

[0009]

A multi-phase multi-pole linear motor according to a first invention of the present application is driven by being controlled by an n-phase (n is an integer of 3 or more) phase current. The magnetic material array and the second magnetic material array are provided. In the first magnetic material arrangement, different magnetic poles are arranged alternately along the moving direction. The second magnetic body array has an effective conductor portion extending in a direction intersecting with the moving direction, and has an armature coil group having an integral multiple of n and including a plurality of armature coils arranged along the moving direction. ing. The effective conductor portions located at the ends of the armature coil group are set to have the same number with respect to the current phase.

The multi-phase multi-pole linear motor according to the second aspect of the present invention is driven by being controlled by an n-phase (n is an even number equal to or greater than 4) phase current, and has a first magnetic material array and a second magnetic body array. And a magnetic material array. In the first magnetic material arrangement, different magnetic poles are arranged alternately along the moving direction. The second magnetic body array has an effective conductor portion extending in a direction intersecting with the movement direction, and is an armature coil group of an integer multiple of n / 2, which includes a plurality of armature coils arranged along the movement direction. have. The effective conductor portions located at the ends of the armature coil group are set to have the same number with respect to the current phase.

[0011]

In the multi-phase multi-pole linear motor according to the present invention, an n-phase current is supplied to the armature coil of the armature coil group of the second magnetic body array. As a result, thrust is generated in the second magnetic body array with respect to the first magnetic body array. However, here, since the effective conductors located at the ends of the armature coil group are set to have the same number with respect to the current phases, the mutual interference characteristics of all the current phases become equal, and the mutual interference characteristics between the current phases are the same. The difference in interference characteristics can be reduced. As a result, it is possible to sufficiently reduce the thrust ripple with a simple configuration.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a multi-phase multi-pole linear DC motor 1 to which an embodiment of the present invention is applied is a stator 2 and a movable member arranged so as to be movable in the longitudinal direction of the stator 2. It is composed of a child 7. The stator 2 has a lower holder 3 and an upper holder 4 which are vertically spaced apart from each other and arranged in parallel. The holders 3 and 4 each have a field in which different poles are alternately arranged in the longitudinal direction. Magnetic magnets 5 and 6 are provided. The field magnets 5 and 6 are arranged so as to have different polarities at positions facing each other (see FIG. 3).

The mover 7 is formed in a U-shaped cross section, and is fitted into the upper and lower holders 4 so as to be movable in the length direction of the stator 2. In the mover 7, the portion of the stator 2 located between the field magnets 5 and 6 has a coil holding portion 8 as shown in FIG. A large number of coils 9 are attached to the coil holding portion 8, and the printed circuit board 1 is attached to the coils 9.
A current controlled by 0 is given. As shown in FIG. 3, a large number of coils 9 held by the coil holding unit 8 are arranged in three armature coil groups 15, 16, 17
Are configured. The coil holding portion 8 holds a further position detecting element 18. The position detection element 18 is composed of a Hall element, and detects the position of the mover 7 by generating a signal by the magnetic fields of the field magnets 5 and 6.

The coil 9 mounted on the moving element 7 is shown in FIGS.
The shape shown in FIG. 7 is obtained by winding a wire into a rectangular frame shape. Here, of the conductor portions formed on the four sides, a pair of long-length portions is the first effective conductor portion 11 and the second effective conductor portion 12.
And the pair of short sides is the first invalid conductor portion 13 and the second
It is the invalid conductor portion 14. The effective conductor portions 11 and 12 extend in parallel with each other, and the extending direction thereof is orthogonal to the moving direction (the horizontal direction in FIG. 3). Both effective conductor portions 11 and 12 are formed in a flat plate shape, and their extending planes are along the moving direction.

The ineffective conductor portions 13 and 14 are inclined by an angle θ with respect to the width direction (moving direction) of the effective conductor portions 11 and 12 when viewed in the direction of FIG. This inclination angle θ is
If the thickness d of 3, 14 and the width of the effective conductor portions 11, 12 are u, then θ = sin ⁻¹ (d / u). As a result, even when a large number of coils 9 are arranged in an overlapping manner as shown in FIG. 8, the conductor length x in which the magnetic flux of the field magnets 5 and 6 effectively acts is kept constant in the moving direction of the moving element 7. Be done.

The first ineffective conductor portion 13 includes both effective conductor portions 11,
It is bent 90 degrees upward (toward the front of Fig. 4) with respect to 12,
The second invalid conductor portion 14 is bent downward (inward in FIG. 4) by 90 °. As a result, it is possible to stack a large number of one type of coil 9 as shown in FIG. Further, since each of the invalid conductor portions 13 and 14 is bent in the opposite direction, it is easy to bend even if the coil thickness is large in order to increase the number of turns. Therefore, the stress applied to the wire in the bending step is small, and the deterioration of the insulation and the dimensional accuracy are unlikely to occur.

As shown in FIGS. 5 to 7, the first effective conductor portion 11 and the second effective conductor portion 12 are provided so as to be displaced in the coil thickness direction by the thickness t of the effective conductor portion. As a result, one type of coil 9 can be overlapped as shown in FIG. 9 without tilting. Here, if the width of the effective conductor portion of the coil 9 is u and the interval between the effective conductor portions 11 is w, the width u of the effective conductor portion is set to have a relationship of approximately u = w / 3. Between the effective conductor portions 11 and 12 of the coil 9,
The coils are overlapped so that one of the effective conductor portions of the other coil is positioned.

In this embodiment, the effective conductor portions 11 and 12 of the 18 coils 9 are piled up as shown in FIG. 3 and housed in the coil holding portion 8 of the moving element 7. A 3-phase motor is assumed here, and a set of two U-phase, V-phase,
Three armature coil groups 15, 16 and 17 each including three coils corresponding to the W-phase current phase are used. The two adjacent coils 9 are connected in parallel as shown in FIG. 8 so that currents of the same phase are supplied. As a result, each coil pair has U-phase and V-phase.
Phase and W phase are set to be configured. Further, in this configuration, the first effective conductor portion 11 of the next coil 9 is overlapped on the upper surface of the second effective conductor portion 12 (see FIGS. 3 and 9).

The field magnet 5 provided on the stator 2
The length of the N pole / S pole pair of 6 is the magnetic pole cycle length L (Fig. 10)
Then, the width w of the coil 9 used here is set to w = L / 2, and the width u of the effective conductor portion is u = w / 3, so that it is approximately u = L / 6. Here, in order to reduce the thrust ripple, the width u of the effective conductor portion of the coil 9 is reduced.
Is preferably in the range of 0.30L ≦ u ≦ 0.36L. In this embodiment, two adjacent coils 9 and 9 are
By supplying currents of the same phase to the
The widths of 1 and 12 are set to be equivalently approximately L / 3.

When the coils 9 and 9 constructed in this way are inserted between the field magnets 5 and 6, it becomes as shown in FIG. However, in FIG. 10, for convenience of understanding,
Only one armature coil group is shown. In FIG. 10, focusing on the V phase, for example, the first effective conductor portion 11
When V is in the upward magnetic flux, the second effective conductor portion 12V
Are arranged so that they are in the downward magnetic flux.

Further, as shown in FIG. 3, a gap corresponding to the two coils 9 is provided between the three armature coil groups 15, 16 and 17. As a result, the U-phase and the W-phase are located at both ends of the armature coil group 15, and the V-phase and the U-phase are located at both ends of the armature coil group 16.
With respect to the armature coil group 17, the W phase and the V phase are located at both ends. That is, in this embodiment, the armature coil groups 15, 16 and 17 are configured so that the current phases at the ends are the same in number as a whole.

The above described embodiment operates as follows. Focusing on the V phase in FIG. 10, if a current flowing from the front side to the back side of the paper surface is applied to the first effective conductor portion 11V, the second effective conductor portion 12
A current flows from V to the front in the plane of the paper, and both generate thrusts f _v and f _v 'to the right. This makes the coil 9
Will be moved to the right in the figure by the force of f _v + f _v '= 2f _v .

[0023] Each current phase U phase, V phase, the thrust f _u obtained by W-phase, f _v, f _w is FIG 10 (b), (c) ,
The solid line is shown in (d). Here, when the position of the effective conductor portion of the coil is near the center of a single magnetic pole,
Since the magnetic flux density passing through the effective conductors is uniform, 10 ideally (b), the waveform of (c), the thrust in (d) of as indicated by the dotted line f _u, f _v, f _w It should have a trapezoidal shape, but since there is a roundness in the magnetic field distribution of the field magnets 5 and 6, the actual waveform is almost a sine wave as shown in the figure. Therefore, the thrust force f of the motor 1 as a whole, which is the combined thrust force of each current phase f _u , f _v , and f _w , is shown in FIG.
As shown by the solid line, the value is almost constant with the thrust ripple removed.

Furthermore, in this embodiment, the armature coil groups 15, 16 and 17 are configured so that the current phases located at the ends are the same in number as a whole, so that the mutual interference characteristics of all the current phases are reduced. Therefore, the mutual interference characteristic difference between the current phases is reduced. As a result, the occurrence of thrust ripple is further reduced. As a result of the experiment, the gain difference of the mutual interference characteristics of the U phase, V phase, and W phase is 1 when the armature is configured by continuously arranging the U phase, V phase, and W phase coils as in the conventional case.
16.3 dB at a current of 10 kHz and 1 at a current of 10 kHz
Although it was 1.3 dB, in this embodiment, it is 1 kHz.
The current was 4.5 dB, and the current at 10 kHz was 5.0 dB. That is, in the experimental device according to this example,
The difference in the mutual interference characteristics of each phase was almost eliminated, and the thrust ripple was reduced.

[Other Embodiments] (a) As shown in FIG. 11, three armature coil groups 1
The gap of 5, 16 and 17 may be four coils. The armature coil group 15 is U phase, V phase, W phase from the left, the armature coil group 16 is W phase, U phase, V phase from the left, and the armature coil group 17 is from the left. V phase, W phase, U
Are in phase.

The experimental result of this configuration shows that 1 kH
The gain difference was 1.8 dB at the current of z, and the gain difference was 1.5 dB at the current of 10 kHz, and the thrust ripple could be almost removed. (B) Three coil groups 19, 20, 21 shown in FIG.
May be used to implement the present invention.

Here, the armature coil group 19 is composed of a pair of adjacent coils to which currents of the same phase are supplied.
W for phase and V phase coils and one coil
It is composed of a phase coil. Armature coil group 2
0 is composed of a V-phase and W-phase coil composed of a pair of adjacent coils to which currents of the same phase are supplied, and a U-phase coil composed of one coil. The armature coil group 21 includes a W-phase and U-phase coil composed of a pair of adjacent coils to which currents of the same phase are supplied, and a V-phase coil composed of one coil. It consists of Further, there is a gap of three coils between each armature coil group.

In this embodiment, the total length of the armature can be shortened. (C) Three coil groups 22, 23, 24 shown in FIG.
May be used to implement the present invention. Here, the armature coil group 22 includes a V-phase coil composed of a pair of adjacent coils to which currents of the same phase are supplied, and U-phase and W-phase coils composed of individual coils. It consists of and. The armature coil group 23 is composed of a W-phase coil composed of a pair of adjacent coils to which currents of the same phase are supplied, and V-phase and U-phase coils composed of individual coils. Has been done. The armature coil groups 24 are adjacent to each other and are supplied with currents of the same phase.
It is composed of a U-phase coil composed of a pair of coils and W-phase and V-phase coils composed of individual coils. Further, there is a gap of four coils between each armature coil group. (D) Three coil groups 25, 26, 27 shown in FIG.
May be used to implement the present invention.

The armature coil group 25 includes U-phase and W-phase from the left.
It is composed of a phase and a V phase, and the W phase is opposite to the other phases. The armature coil group 26 includes a W phase, V from the left.
It is composed of a phase and a U phase, and the W phase and the U phase are opposite phases. Further, the armature coil group 27 includes V phase from the left,
It is composed of U and W phases, and the U phase is the opposite phase. A gap corresponding to the width of the effective conductor portion of the coil is provided between each armature coil group 25, 26, 27.

In this embodiment, each armature coil group 25,
The number of effective conductor portions located at both ends of 26 and 27 is the same for each current phase, and mutual interference characteristics are improved as in the above-described embodiments. (E) The present invention may be implemented using three or more units of the armature coil group described above. For example, in the case of three phases, 6, 9, 12 ... Armature coil groups may be used. (F) The present invention can be similarly applied to a multi-phase multi-pole linear motor having four or more phases. In this case, an armature coil group having an integral multiple of the number of phases may be used. (G) For an even-phase multi-pole linear motor having four or more phases, an effective conductor located at the end of the armature coil group is used by using an armature coil group that is an integral multiple of 1/2 of the number of phases. The parts can be set to have the same number with respect to the current phase. Therefore, the present invention can also be implemented with this configuration.

In FIG. 15, as one embodiment of this case, 2
4 shows a four-phase multi-pole linear motor having individual armature coil groups 28, 29.

[0032]

In the multi-phase multi-pole type linear motor according to the present invention, the effective conductor portions located at the ends of the armature coil group are set to have the same number with respect to the current phase, so that all current phases are The mutual interference characteristics can be made equal, and the difference in mutual interference characteristics between the current phases can be reduced. As a result,
With a simple structure, it is possible to sufficiently reduce the thrust ripple.

[Brief description of drawings]

FIG. 1 is a schematic perspective partial view of a linear motor according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a partial sectional view taken along the line III-III in FIG.

FIG. 4 is a plan view of an armature coil.

FIG. 5 is a side view thereof.

FIG. 6 is a bottom view thereof.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a plan view of an armature coil group configured by using the coils of FIGS. 4 to 7.

9 is a sectional view taken along line IX-IX in FIG.

FIG. 10 is an explanatory diagram showing a relationship between a field magnet and an effective conductor portion of a coil and a thrust change.

FIG. 11 is a view corresponding to FIG. 3 of another embodiment.

FIG. 12 is a view corresponding to FIG. 3 of still another embodiment.

FIG. 13 is a diagram corresponding to FIG. 3 of still another embodiment.

FIG. 14 is a view corresponding to FIG. 3 of still another embodiment.

FIG. 15 is a view corresponding to FIG. 3 of still another embodiment.

[Explanation of symbols]

 1 multi-phase multi-pole type linear direct current motor 2 stator 5,6 field magnet 7 mover 9 coil 11,12 effective conductor part 15,16,17 armature coil group

Claims (2)

[Claims] 1. A multi-phase multi-pole type linear motor driven by being controlled by an n-phase (n is an integer of 3 or more) phase current, wherein different magnetic poles are alternately arranged along a moving direction. A body array, and an armature coil group having an integral multiple of n, which has an effective conductor portion extending in a direction intersecting with the moving direction and is composed of a plurality of armature coils arranged along the moving direction, A multi-phase multi-pole type linear motor comprising: a second magnetic body array in which the effective conductor portions located at the ends of the armature coil group are set to have the same number with respect to the current phase. 2. A multi-phase multi-pole type linear motor driven by being controlled by an n-phase (n is an even number of 4 or more) phase current, wherein different magnetic poles are alternately arranged along a moving direction. A body array, and an armature coil group having an effective multiple of n / 2 and having an effective conductor portion extending in a direction intersecting the moving direction and including a plurality of armature coils arranged in the moving direction. A second magnetic body array in which the effective conductor portions located at the end portions of the armature coil group are set to have the same number with respect to the current phase, and a multi-phase multi-pole type linear motor.