JPH05276733A - Linear direct current motor - Google Patents

Abstract

PURPOSE:To obtain a smooth thrust ripple characteristic and to make the thrust larger by arranging and forming armature coils at equal intervals of a specified pitch respectively, and arranging and forming two sets of field magnets or more shifting their phases in the moving direction of a moving part by a specified distance respectively. CONSTITUTION:An armature 2 made by arranging armature coils 5 formed into the same width T as the pole width of field magnets 6 by a width pitch lambda(where lambda=T+T/8), and a stator having pole discriminating elements 7 are arranged at relatively moving positions to the field magnets 6. A moving part 3 has the field magnets 6 composed of 2 sets of field magnets 6A and 6B arranged with their phases shifted by a distance of pole width n(1+1/8)lambda (where n is an integer of 1 or larger, and lambda=T+T/8) in the moving direction of the moving part 3, on the inside bottom of a long platelike magnet yoke 8. The 2 sets of field magnets 6A and 6B are formed into a rectangular shape by arranging N- and S-magnetic poles of width T adjacent to each so that adjoining poles may be opposite poles to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear DC motor having an extremely smooth thrust ripple.

[0002]

2. Description of the Related Art FIG. 4 shows a movable magnet type linear DC brushless motor 1-1 as a conventional multi-pole / multi-phase type linear DC motor, which will be described below. In this movable magnet type linear DC brushless motor 1-1, an 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. Is configured.

A linear motion guide rail (not shown) is made of a magnetic material in order to serve also as a stationary yoke on the fixed side, and an appropriate means is provided on the linear motion guide rail surface. A long plate-shaped printed wiring board 4 on which a conductive printed wiring pattern is formed (not shown) is arranged.

In this case, when the linear guide rail 3 is not made of a magnetic material, the printed wiring board 4 is arranged after the magnetic material plate is interposed.

On the surface of the printed wiring board 4, a moving element 3-1 is provided.
Of the air-core type armature coils 5 along the longitudinal direction of λ (where λ = T + T / 8, where T is the field magnet 6-
The width of one magnetic pole is equal to one pitch, and the coreless stations of the coreless structure are arranged adjacent to each other so as not to overlap each other.
The armature 2 is formed.

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

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

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

In the armature coil 5, the length between the two conductor portions 5b that do not contribute to the generation of the thrust and the outside of the conductor portion 5b is slightly shorter than the width of the field magnet 6-1 in that direction. It is formed into a thing.

The printed wiring board 4 has an armature coil 5
The 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 to discriminate the magnetic pole of the armature coil 5. A power supply is supplied to the element 7 and a conductive wiring pattern (not shown) for obtaining an output signal is formed.

The magnetic pole discriminating element 7 is a hole I.
An appropriate magnetoelectric conversion element such as C, a hall element, a magnetoresistive element or the like may be used.

The magnetic pole discriminating element 7 group includes a conductor portion 5a which contributes to the thrust generated by the armature coil 5 and a conductor portion 5b which is formed orthogonal to the conductor portion 5a and does not contribute to thrust generation.
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 the field magnet 6-1 on the conductor extension line intersecting with and. I am able to do it.

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 N pole and the S pole of the field magnet 6-1 to operate thrust in a predetermined direction. So that the armature coil group 5 is energized in an appropriate direction.

The mover 3 which moves linearly relative to the armature 2 has a field magnet 6 on the inner surface of the lower portion of the elongated plate-shaped magnet yoke 8-1 which faces the armature 2 with a gap. -1 is provided to make relative movement.

On the inner surface of the lower portion of the magnet yoke 8-1,
P (P
Is an integer greater than or equal to 2) 10 formed by adjoining at equal intervals.
The pole field magnet 6-1 is fixed by using an appropriate means such as an adhesive.

[0016]

2. Description of the Related Art In the movable magnet type linear DC brushless motor 1-1 having the above structure, the thrust (torque) ripple obtained when the mover 3-1 moves is shown in FIG. Obtained as shown.

Explaining further with reference to FIG. 5, the armature coil groups 5 are now arranged at equal intervals of λ (T + T / 8) pitch to form the armature 2 and the field magnet 6 is formed.
Assuming that only the five poles of -1 are taken, when the field magnet 6-1 moves relative to the armature 2, the thrust ripple curve 9-1 in the range of λ above shows the thrust ripple as shown in FIG. Appears as a rough thing.

Since the movable magnet type linear DC brushless motor 1-1 of this kind has a coreless structure and a multi-phase structure, it can be used as a linear pulse motor or an iron core type linear DC motor. It is used in high-precision measuring instruments, etc., as it has extremely smooth thrust ripple characteristics in comparison.

Here, a smoother thrust ripple characteristic is required for a linear DC motor used in an apparatus requiring higher precision such as a semiconductor manufacturing apparatus.

[0020]

SUMMARY OF THE INVENTION According to the present invention, a thrust ripple is compared with a conventional one by only making a slight design change to a linear DC motor such as the movable magnet type linear DC brushless motor 1-1 described above. By doubling the number, it is a subject to suppress the thrust ripple to ½ and to make the moving element run extremely smoothly, and to improve the combined thrust characteristics.

[0021]

The object of the present invention is to form the armature coils constituting the armature at regular intervals of λ pitch, and to form the field magnets in two or more sets. The field magnets of more than one set are n (1+
This can be achieved by arranging and forming the magnetic pole width of 1/8) (where λ = T + T / 8) with the phase shifted in the moving direction of the moving element.

[0022]

Operation of the invention Two sets of five-pole field magnets 6A and 6B
Is approximately (1 + 1/8) λ magnetic pole 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 moves is shown in FIG. 5 pole magnetic field magnet 6
When A and 6B move relative to the armature 2, the thrust ripple curves 9A and 9B obtained by the five-pole field magnets 6A and 6B in the range of λ are (1 + 1/8) λ Deviation, and not only a very smooth thrust ripple characteristic is obtained, but also a combined thrust curve 1 in which two thrust ripple curves 9A and 9B are combined.
Since 0 is a high thrust level, it is a movable magnet type linear DC brushless motor 1 that can obtain a larger thrust.

[0023]

1 is a schematic exploded perspective view of a movable magnet type linear DC brushless motor 1 of the present invention, and FIG. 2 is a field magnet 6 and armature of the linear DC brushless motor 1. In the development view with the armature 2 consisting of 5 coils,
FIG. 3 is an explanatory view of a thrust ripple curve and a combined thrust curve obtained by the present invention, omitting the description of the common parts described with reference to FIGS. I will explain. Also, common points will be described using the same reference numerals.

In the movable magnet type linear DC brushless motor 1 of the present invention, like the linear DC brushless motor 1-1, the open angle width of the conductor portions 5a and 5a contributing to the thrust is set to the field magnet 6-1. The armature coil 5 formed with the same T width as the one magnetic pole width T is arranged at a λ (where λ = T + T / 8) width pitch, and the magnetic pole discrimination arranged at the same condition position as the above condition. The stator having the element 7 is arranged at a position that moves relative to the field magnet 6 described later, as in the movable magnet type linear DC brushless motor 1-1 described above. This is in the configuration of the mover 3 having the magnet 6.

The mover 3 is the magnet yoke 8-1.
Two sets of field magnets 6A and 6B are formed on the inner lower surface of a similar long plate-shaped magnet yoke 8 in a substantially n (1 + 1/8) λ range.
(N is an integer greater than or equal to 1. In this embodiment, n = 1 is selected) The magnetic pole width is arranged and formed by shifting the phase in the moving direction of the moving element 3 by a distance of λ = T + T / 8. A field magnet 6 is provided.

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 formed as a five-pole elongated plate formed by arranging magnetic poles adjacent to each other.

Between the two pairs of field magnets 6A and 6B, between the magnet yokes 8 is a field magnet positioning member 1 made of a non-magnetic material such as resin, adhesive, copper or aluminum.
1 is provided.

A development view of the mover 3 having the field magnet 6 composed of the two sets of field magnets 6A and 6B as described above, and the armature 2 including the magnetic pole discriminating element 7 group and the armature coil 5 group. Can be represented as shown in FIG.

As the magnetic pole discriminating element 7, a 4-terminal hole is used.
2 power supply terminals and 2 output terminals are connected to a control circuit (not shown).

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

In the case of the movable magnet type linear DC brushless motor 1, two sets of 5-pole field magnets 6A and 6B are used.
Is approximately (1 + 1/8) λ magnetic pole 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 moves is shown in FIG. Is obtained as.

Explaining further with reference to FIG. 3, now, the armature coil groups 5 are arranged at equal intervals of λ (T + T / 8) pitch to form the armature 2 and form a 5-pole field magnet. When each of 6A and 6B moves relative to the armature 2, a 5-pole field magnet 6A,
6B, thrust ripple curves 9A,
9B, the phases are (1 + 1/8) λ deviated from each other.

According to the two thrust ripple curves 9A and 9B, the conventional movable magnet type linear DC brushless motor is used.
2 is obtained because the double ripple number is obtained as compared with the thrust ripple curve 9-1 shown in FIG.
The thrust ripple curve composed of the two thrust ripple curves 9A and 9B has an extremely smooth thrust ripple characteristic that is 1/2 as smooth as the thrust ripple curve 9-1 shown in FIG. The magnet type linear DC brushless motor 1 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 are obtained. As shown in FIG. 3, the combined thrust curve 10 in which 9A and 9B are combined also has a high thrust level, so that the movable magnet type linear DC brushless motor 1 capable of obtaining a larger thrust can be obtained.

[0035]

Other Embodiments In the above embodiment, an example using two sets of five-pole field magnets 6A and 6B is shown, but each field magnet may be formed of three or more poles.
Further, if it is arranged so as to obtain the effect of the present invention, it may be formed by using three or more sets of field magnets, and the armature side is the moving element and the field magnet side is the stator. It goes without saying that the movable armature type linear DC motor may be formed. Furthermore, the present invention is naturally applied to not only linear DC brushless motors but also linear DC motors of the type that uses a brush and a commutator for rectification.

[0036]

According to the linear DC motor of the present invention, two or more sets of field magnets are formed by slightly arranging N and S poles adjacent to each other. The magnetic magnets are arranged and formed by shifting the phase in the moving direction of the moving element of the moving element by a distance of n (1 + 1/8) λ (n is an integer of 1 or more) magnetic pole width (where λ = T + T / 8). Only by doing so, the thrust ripple characteristic can be made extremely smooth and the thrust characteristic can be improved compared to the conventional one.

[Brief description of drawings]

FIG. 1 is a schematic exploded perspective view of a multipole / multiphase movable magnet type linear DC brushless motor according to an embodiment of the present invention.

FIG. 2 is a development view of two sets of field magnets and an armature including an armature coil group of the same linear DC brushless motor.

FIG. 3 is an explanatory diagram of a thrust ripple curve and a combined thrust curve obtained by the linear DC brushless motor.

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

FIG. 5 is an explanatory diagram of a thrust ripple curve obtained by the linear DC brushless motor.

[Explanation of symbols]

1,1-1 Movable magnet type linear DC brushless motor 2 Coreless stator Armature 3 Moving element 4 Printed wiring board 5 Armature coil 5a Conductor part 5b that contributes to thrust generation 5b Conductor part that does not contribute to thrust generation 6 , 6A, 6B, 6-1 Field magnet 7 Magnetic pole discrimination element 8, 8-1 Magnet yoke 9A, 9B, 9-1 Thrust ripple curve 10 Combined thrust curve 11 Field magnet positioning member

Claims (1)

[Claims] 1. An N pole magnetized with a width equal to T width so that adjacent magnetic poles along the traveling direction of the mover have different poles.
A field magnet having a P (P is an integer of 2 or more) pole having an S pole, and armatures formed by arranging armature coils at equal intervals so as to move relative to the field magnet, In a linear DC motor having one of the armature and the field magnet as a mover and the other as a stator, the armature coils constituting the armature are each λ (where λ = T + T / 8). ) The magnetic field magnets are formed at equal intervals, and the field magnets are formed in two or more sets, and each of the two or more sets of field magnets is n (1 + 1/8) λ.
(N is an integer of 1 or more) A linear DC motor characterized in that it is arranged and formed by shifting the phase of the moving element in the moving direction of the moving element by the distance of the magnetic pole width.