JPH07123345B2 - Movable magnet type linear DC motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable magnet type linear DC motor capable of improving thrust by reducing the weight of a moving element and lightening the load, and obtaining smooth thrust ripple characteristics. Regarding

[0002]

2. Description of the Related Art FIG. 4 shows a conventional multi-pole / multi-phase movable magnet type linear DC brushless motor 1-1, which will be described below. This movable magnet type linear DC brushless motor 1-1 is configured such that a coreless stator armature 2 is arranged on a linear motion guide rail (not shown), and a mover 3-1 moves linearly along the linear motion guide rail. ing.

A linear motion guide rail (not shown) is made of a magnetic material so as to also serve as a stator yoke on the fixed side. The linear motion guide rail surface is provided with an appropriate means.
A long plate-shaped printed wiring board 4 having a conductive printed wiring pattern (not shown) is arranged.

When a linear guide rail which is not made of a magnetic material is used, the printed wiring board 4 is arranged via a magnetic material plate. On the printed wiring board 4, air-core type armature coils 5 are arranged along the longitudinal direction of the mover 3-1 with approximately λ (where λ = T + T / 8, where T is one magnetic pole of the field magnet 6-1). The coreless stator armatures 2 having a coreless structure are formed by arranging them at equal intervals with adjacent pitches so as not to overlap each other.

Explaining the armature coil 5, the armature coil 5 in this example is formed by winding a large number of turns of a conductive wire so as to form a rectangular frame-shaped air-core type coil. It may be formed by a sheet coil or the like using a plating means or an etching means.

According to the air-core type armature coil group 5 as described above, the linear reciprocating 180-degree energization method with good efficiency and performance is extended in the direction orthogonal to the traveling direction of the moving element 3-1. The opening angle between the two effective conductor portions 5a and 5a that contribute to the generation of thrust is determined by the N pole, S in the traveling direction of the moving element 3-1 of the field magnet 6-1 to be described later.
The winding is formed so as to have an opening angle of one pole width T of the pole.

In the armature coil 5, the mover 3-
The two conductor portions 5b parallel to the moving direction of 1 are conductor portions that do not contribute much to the generation of thrust.

In the armature coil 5, the two conductor portions 5b that do not contribute much to the generation of the thrust and the length to the outside of the conductor portion 5b are slightly shorter than the width of the field magnet 6-1 in that direction. Form in length.

An armature coil 5 is provided on the printed wiring board 4.
A magnetic pole discriminating element 7 such as a Hall element for position detection for switching the energization of the armature coil 5 group according to the magnetic pole state of the group and the field magnet 6 is arranged, and the armature coil 5 and the magnetic pole discriminating element. Power is supplied to 7 and a conductive wiring pattern (not shown) for obtaining an output signal is formed.

As the magnetic pole discriminating element 7, a Hall I is used.
An appropriate magnetoelectric conversion element such as C, a Hall element, or a magnetoresistive element may be used.

In the magnetic pole discriminating element 7 group, a conductor portion 5a that contributes to the thrust generated by the armature coil 5 and a conductor portion 5b that is formed orthogonal to the conductor portion 5a and that does not contribute much to the thrust intersect. Field magnet 6 on the conductor extension
The magnetic poles of the N pole and the S pole of the field magnet 6-1 can be detected by arranging them on the surface of the printed wiring board 4 facing -1.

A driver in an energization control circuit (not shown) operates based on an output signal from the magnetic pole discriminating element 7 corresponding to the magnetic poles of the north pole and the south pole of the field magnet 6-1 to generate thrust in a predetermined direction. The armature coil group 5 is energized in an appropriate direction so as to be generated.

The mover 3-1 is a long plate magnet yoke.
The coreless stator armature 2 on the inner surface of the lower portion of
A field magnet 6-1 is provided on the surface opposite to and through a gap so as to move relative to the stator armature 2.

On the lower inner surface of the magnet yoke 8-1,
The magnetic poles of the N pole and the S pole, which are formed in the T width so that the magnetic poles adjacent to each other along the moving direction of the mover 3-1 have different poles, are set to P.
(P is an integer of 2 or more) The ten-pole field magnets 6-1 formed adjacently at equal intervals are fixed using an appropriate means such as an adhesive.

In the movable magnet type linear DC brushless motor 1-1 having the above structure, the moving element 3-
The thrust (torque) ripple obtained when 1 moves is obtained as shown in FIG.

Explaining further with reference to FIG. 5, the armature coil groups 5 form coreless stator armatures 2 arranged at equal intervals with a pitch of approximately λ (T + T / 8), and a field magnet 6-. If only 5 poles of 1 are taken up, the field magnet 6-1 is the coreless stator armature 2
In the range of λ, the thrust ripple curve 9-1 appears as a rough thrust ripple as shown in FIG.

Since the movable magnet type linear DC brushless motor 1-1 of this kind has a coreless structure and a multi-phase structure, it has a smoother thrust than that of the linear pulse motor or the iron core type linear DC motor. It is used in advanced precision measuring instruments and the like as it has ripple characteristics.

Here, a smoother thrust ripple characteristic is required for a movable magnet type linear DC motor used in a device requiring higher precision such as a semiconductor manufacturing device.

Therefore, the inventor of the present invention doubles the thrust ripple number and halves it as compared with the conventional one by only slightly changing the design of the movable magnet type linear DC brushless motor 1-1. It is configured so that the thrust 8 can be suppressed and the movement 8 can be run extremely smoothly.
A movable magnet type linear DC brushless motor 1-2 shown in FIG. 6 capable of improving the combined thrust characteristics.
Since it has already been proposed, this will be described below with reference to FIG.

In this movable magnet type linear DC brushless motor 1-2, the conductor portion 5 which contributes to thrust like the movable magnet type linear DC brushless motor 1-1.
The open angle width of a and 5a is set to one magnetic pole width T of the field magnet 6-1.
The armature coil 5 formed to have the same width as λ (where λ =
T + T / 8) The coreless stator armature 2 arranged at a width pitch and the magnetic pole discriminating element 7 arranged at the same condition position as the above condition are held on the fixed side, and are arranged at a position relatively moving with the field magnet 6 described later. The points are the same as those of the movable magnet type linear DC brushless motor 1-1 described above, and the difference is in the configuration of the mover 3-2 having the field magnet 6.

The mover 3-2 is the magnet yoke 8 described above.
−1, two sets of field magnets 6A and 6B are provided on the inner lower surface of a long plate-shaped magnet yoke 8-2 similar to (-1 + 1).
/ 8) It is arranged and formed with the phase shifted by a distance of λ width (where λ = T + T / 8) in the moving direction of the moving element 3-2.

The two sets of field magnets 6A and 6B have N poles and S poles of approximately T width so that adjacent magnetic poles have different poles.
It is a long plate having five poles formed by arranging poles adjacent to each other, and these poles are arranged at intervals of (1 + 1/8) λ as described above.

In this way, the field magnet 6 is divided into two sets of field magnets 6A and 6B, and the width of one magnetic pole of N pole and S pole of the field magnets 6-1 and 6 is formed to be T width. Therefore, when the width T of one magnetic pole of the N pole and the S pole in the moving direction of the movers 3-1 and 3-2 is set to 30 mm, as shown in FIG.
Movable magnet type linear DC brushless motor 1-1
7, the field magnet 6-1 has a length of 300 mm in the longitudinal direction as shown in FIG. 7, whereas the field magnet 6 in the case of the movable magnet type linear DC brushless motor 1-2 In this case, since the two field magnets 6A and 6B are arranged with the above condition separated by a width of (1 + 1/8) λ, only the width of (1 + 1/8) λ, that is, FIG. 35mm long 335 as shown in
mm.

The field magnets 6-1 and 6 are fixed to the magnet yokes 8-1 and 8-2, and the outer ends thereof are longer by + α than the field magnets 6-1 and 6-2. To form.

On the lower surface of the magnet yoke 8, a resin, an adhesive, copper, and the like are provided in the gap between the two sets of field magnets 6A and 6B.
A field magnet positioning member 11 made of a non-magnetic material such as aluminum is provided.

A mover 3 having a field magnet 6 composed of two sets of field magnets 6A and 6B as described above.
An exploded view of the coreless stator armature 2 including the magnetic pole discriminating element 7 group and the armature coil 5 group can be expressed as shown in FIG.

A 4-terminal Hall element is used as the magnetic pole discriminating element 7, and two power supply terminals and two output terminals are connected to a control circuit (not shown).

When the power supply of the control circuit is closed and the movable magnet type linear DC brushless motor 1 is in an operable state, the magnetic poles for detecting the N pole and S pole of the field magnets 6A and 6B are detected. Based on the output from the discriminating element 7, the armature coil 5 facing the field magnets 6A and 6B is energized in a predetermined direction to obtain thrust in the predetermined direction, and the mover 3 is not shown. It runs in a predetermined direction under the control of signals from the encoder and control circuit.

In the case of the movable magnet type linear DC brushless motor 1-2, the two sets of five-pole field magnets 6A and 6B are approximately (1 + 1/8) λ width (where λ = T + T /
Since the field magnet 6 arranged and formed with the phase shifted by the distance of 8) in the moving direction of the moving element 3 is used, the thrust (torque) ripple obtained when the moving element 3-2 moves is shown in FIG. It is obtained as shown in.

This will be further explained with reference to FIG. 10. Now, the armature coil groups 5 are arranged at equal intervals of λ (T + T / 8) pitch to form the coreless stator armature 2, and the five-pole field is formed. When the magnetic magnets 6A, 6B respectively move relative to the coreless stator armature 2, the thrust ripple curves 9A, 9B obtained by the 5-pole field magnets 6A, 6B in the range of λ are shown in FIG.
, The phase is shifted by (1 + 1/8) λ from each other. According to the two thrust ripple curves 9A and 9B, twice the number of ripples can be obtained as compared with the thrust ripple curve 9-1 shown in FIG. 5 obtained by the moving magnet type linear DC brushless motor 1-1 before the conventional method. Therefore, the thrust ripple curve obtained by combining the two thrust ripple curves 9A and 9B has a smooth thrust ripple characteristic of 1/2 as compared with the conventional thrust ripple curve 9-1 shown in FIG. A movable magnet type linear DC brushless motor 1-2 having thrust ripple characteristics can be obtained.

Further, as compared with the thrust ripple curve 9-1 shown in FIG. 5 obtained by the conventional movable magnet type linear DC brushless motor 1-1, the number of ripples is doubled, so that two thrust ripple curves 9A, As shown in FIG. 10, the combined thrust curve 10 in which 9B is combined also has a high thrust level, so that the movable magnet type linear DC brushless motor 1-2 capable of obtaining a larger thrust can be obtained.

The movable magnet type linear DC brushless motor 1-2 improved as described above is very useful.

[0033]

However, if the type of the field magnet 6 is changed for the purpose of further improving the performance of the movable magnet type linear DC brushless motor 1-2, depending on the type, In addition to the weight of the field magnet 6, it is necessary to use a thick and heavy magnet yoke 8-2 in order to sufficiently close the magnetic path of the field magnet 6, resulting in a movable magnet type having a large load burden. There is a defect that the linear DC brushless motor 1-2 is used.

The magnet yoke 8-2 is substantially (1 + 1) more than the magnet yoke 8-1 for the above reason.
/ 8) Since the magnet yoke has to be formed to have a long width of λ, the weight of the magnet yoke 8 is heavy.
2 has to be used, and it has a drawback that it becomes a movable magnet type linear DC brushless motor 1-2 that has an even larger load burden.

[0035]

SUMMARY OF THE INVENTION An object of the present invention is to reduce the load on the moving element 3-2 of the linear DC brushless motor 1-2 without sacrificing the characteristics of the movable magnet type linear DC brushless motor 1-2 described above. And to facilitate positioning of the two magnets 6A and 6B to obtain a movable magnet type linear DC brushless motor with better performance.

[0036]

The object of the present invention is as follows.
Each coreless stator armature is λ (where λ = T +
T / 8. T is a group of armature coils formed at equal intervals of the width of one magnetic pole of the field magnet, and the magnet yoke of the mover is formed separately, and the magnetic poles adjacent to each divided magnet yoke have different poles. A split magnet is formed by providing a field magnet having P magnetic poles of N and S poles (P is an integer of 2 or more) magnetized so that the width T is equal to Indicates that the field magnets are (1
+1/8) A distance of λ width is arranged and formed with the phase shifted in the moving direction of the moving element, and it is made of a material having a specific gravity lower than that of the split magnet yoke of the split moving element, and two or more split moving elements are connected to form an integral body. This can be achieved by providing a split moving element positioning member that allows the movable element to move in the space between the field magnets.

[0037]

Operation of the invention Two sets of five-pole field magnets 6A and 6B
Since the field magnet 6 is arranged and formed by shifting the phase in the moving direction of the moving element 3 by a distance of approximately (1 + 1/8) λ width (where λ = T + T / 8), the moving element 3 is Fig. 1 shows the thrust (torque) ripple obtained when moving.
5 field magnets 6A, 6
When each of B moves relative to the coreless stator armature 2, the five-pole field magnet 6 in the range of λ is
Thrust ripple curve 9 obtained by A and 6B respectively
Like A and 9B, the phases are substantially (1 + 1/8) λ deviated from each other, and not only a very smooth thrust ripple characteristic is obtained, but also the combined thrust curve 10 in which the two thrust ripple curves 9A and 9B are combined has a high thrust. Since the level becomes the level, the movable magnet type linear DC brushless motor 1 can obtain a larger thrust.

Further, in the moving element 3, the two divided moving elements 3A and 3B are arranged apart from each other, and since the magnet yoke and the field magnet are not present in the separated portions,
The weight of the moving element 3 can be reduced, and the moving magnet type linear DC brushless motor 1 with a small load burden is obtained.

[0039]

1 is a perspective view showing a main part of a movable magnet type linear DC brushless motor 1 according to an embodiment of the present invention, and FIG. 2 is a main part of a moving element 3 of the movable magnet type linear DC brushless motor 1. 3 is a side view of the mover 3 shown in FIG. 2. FIG.

The movable magnet type linear DC brushless motor 1 of the present invention differs from the conventional movable magnet type linear DC brushless motors 1-1 and 1-2 only in the moving element 3.

The movable magnet type linear DC brushless motor 1 of the present invention has the same length as the moving element 3 in the moving direction like the moving element 3-2 of the conventional moving magnet type linear DC brushless motor 1-2. Will be things.

However, the magnet yoke 8 of the moving element 3 of the movable magnet type linear DC brushless motor 1 (composed of divided magnet yokes 8A and 8B).
Is a moving element 8 of the movable magnet type linear DC brushless motor 1-1 as a whole as shown in FIGS.
-1 can be configured to have the same length as the length of the magnet yoke 8-1. That is, compared to the magnet yoke 8-2 used for the mover 3-2 of the movable magnet type linear DC brushless motor 1-2, the above condition: (1 + 1/8)
Since the magnet yoke 8 can be shortened by the length of the λ width, the weight of the magnet yoke 8 becomes lighter, and the weight of the mover 3 can be reduced, so that the movable magnet type linear DC brushless motor 1 with a reduced load can be configured.

This is because the movable magnet type linear DC brushless motor 1 of the present invention uses two sets of field magnets 6A and 6B as in the conventional movable magnet type linear DC brushless motor 1-2. Despite the above, the magnet yoke 8-1 of the conventional movable magnet type linear DC brushless motor 1-1 is divided into two at the center position in the longitudinal direction to form two divided magnet yokes 8A. , 8B,
The two split magnet yokes 8A and 8B have the above conditions;
The magnet yoke 8 of the movable magnet type linear DC brushless motor 1-2 is displaced by the length of (1 + 1/8) λ in the longitudinal direction of the mover 3 and is thus arranged.
This is because the length in the longitudinal direction can be made shorter than 2.

That is, the two split magnet yokes 8
The length when A and 8B are connected in the longitudinal direction of the moving element 3 can be formed to have the same length as the magnet yoke 8-1 of the movable magnet type linear DC brushless motor 1-1.

Each of the two split magnet yokes 8A and 8B formed as described above has an end portion of the split magnet yokes 8A and 8B located adjacent to each other.
The field magnets 6A, 6B are attached to the surfaces of the split magnet yokes 8A, 8B facing the coreless stator armature 2 with the ends of the field magnets 6A, 6B aligned, and the two split movers 3A, 3B are fixed. Form.

In order to improve the thrust force and the thrust ripple characteristic, it is necessary to form the two movers 3A and 3B into a mover 3 which moves integrally and integrally. It is necessary to position and arrange the magnets 6A and 6B in the longitudinal direction of the moving element 3 by the width of the above condition: (1 + 1/8) λ.

In order to position the two field magnets 6A and 6B in the longitudinal direction of the moving element 3 with a distance of the above condition: (1 + 1/8) λ, the two dividing moving elements 3A and 3B should be separated from each other. Must be correctly positioned and integrated.

Therefore, in the movable magnet type linear DC brushless motor 1, the split magnet yoke 8 is used.
The width between the A and 8B is (1 + 1/8) in the longitudinal direction.
This positioning member 1 uses a convex split mover positioning member 13 having a positioning projection 12 having a width of λ formed at the lower end.
The positioning protrusion 12 of 3 is divided into the magnet yokes 8A and 8
It is fitted between B, and both flanges 14 of the positioning member 13 are engaged with the upper surfaces of the split magnet yokes 8A and 8B and fixed by an appropriate means such as adhesive fixing, screw fixing, etc. The movers 3 and 3B are connected and integrated,
A field magnet 6 is provided at the connecting portion of the split moving element that moves together.
Configures a mover 3 that does not exist.

Since one of the objects of the present invention is to reduce the weight of the moving element 3 and to reduce the load on the movable magnet type linear DC brushless motor 1, the above-mentioned split moving element positioning member 13 is used. The positioning projection 12 is formed to have a thickness of about the thickness of the split magnet yokes 8A and 8B, and the material is lighter than the material forming the split magnet yokes 8A and 8B. It is convenient to use a material that is hard to close magnetically, for example, a non-magnetic material such as an aluminum material, a copper material, or a resin material.

[0050]

According to the movable magnet type linear DC motor of the present invention, the weight of the moving element can be reduced, and the thrust force and the thrust ripple characteristic can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a movable magnet type linear DC brushless motor as an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a main part of a mover of the movable magnet type linear DC brushless motor.

3 is a side view of the mover of FIG. 2. FIG.

FIG. 4 is a schematic exploded perspective view of a first conventional example of a multi-pole multi-phase movable magnet type linear DC brushless motor.

FIG. 5 is an explanatory diagram of a thrust ripple curve obtained by a first conventional example of a movable magnet type linear DC brushless motor.

FIG. 6 is a perspective view showing a main part of a second conventional example of a movable magnet type linear DC brushless motor.

FIG. 7 is an explanatory diagram of a field magnet used in a first conventional example of a movable magnet type linear DC brushless motor.

FIG. 8 is an explanatory diagram of a field magnet used in a second conventional example of a movable magnet type linear DC brushless motor.

FIG. 9 is a development view of two sets of field magnets and a coreless stator armature including an armature coil group of a second conventional example of a movable magnet type linear DC brushless motor.

FIG. 10 is an explanatory diagram of a thrust ripple curve and a combined thrust curve obtained by a second conventional example of a movable magnet type linear DC brushless motor.

[Explanation of symbols]

1,1-1,1-2 Movable magnet type linear DC brushless motor 2 Coreless stator armature 3,3-1,3-2 Moving element 3A, 3B Split moving element 4 Printed wiring board 5 Armature coil 5a Generation of thrust Conductor part 5b that does not contribute to the generation of thrust 6,6A, 6B, 6-1 Field magnet 7 Magnetic pole discrimination element 8, 8-1, 8-2 Magnet yoke 8A, 8B Split magnet yoke 9A, 9B , 9-1 Thrust ripple curve 10 Combined thrust curve 11 Field magnet positioning member 12 Positioning protrusion 13 Split mover positioning member 14 Tsuba

Claims (1)

[Claims] 1. A stator provided with a stator armature along the traveling direction of a mover, and an N pole arranged adjacent to a magnet yoke surface facing the stator armature have different polarities.
A movable magnet type linear DC motor having a field magnet formed by providing P magnetic poles of S and S poles (P is an integer of 2 or more), and having a mover that moves relative to the stator armature, Each stator armature is approximately λ
(Where λ = T + T / 8: T is the width of one magnetic pole of the field magnet), the armature coil group is arranged substantially at equal intervals, and the magnet yoke of the mover is formed separately. A field magnet having P magnetic poles of N and S poles (P is an integer of 2 or more) magnetized so that the magnetic poles adjacent to each of the divided magnet yokes have different polarities. A split mover is formed, and the field magnets of the split mover are shifted in phase in the moving direction of the mover from the field magnets of the other split movers by a distance of approximately (1 + 1/8) λ. The split mover positioning member, which is arranged and formed, is made of a material having a specific gravity smaller than that of the split magnet yoke of the split mover, and which connects two or more split movers and allows them to move integrally, between the field magnets. while A movable magnet type linear direct current motor characterized by being provided in a gap.