JPH07322597A - Linear d.c. brushless motor - Google Patents

Abstract

PURPOSE:To make possible smooth travel without any cogging torque by placing a position detecting element in a long housing groove extending in the direction of length of a yoke member placed on an armature, in an opposite position to a conductor section that contributes to generated thrust of a surface opposed to a field magnet and an opposite surface. CONSTITUTION:A position detecting element housing groove (DP) 12 is formed in the center of a stator yoke 3; the groove extends in the direction of length. DP 12 is widened at its opening end to form an engaging stepped area 13. The width of the engaging stepped area 13 is harmonized with that of a printed board(PB) 14. The long plate-shaped PB 14 is bonded to the underside of armature coils 6 with adhesive. PB 14 is made of a front-back through hole board. Both the terminals 15 of the armature coils 6 are led to the underside of PB 14, and there connected with the output terminals of a position detecting element 17, soldered to the underside of PB 14. The printed board 14 is buried in DP 12 using adhesive applied to the engaging stepped area 13 with the position detecting element 17 facing DP 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multipolar multiphase linear DC
It relates to a brushless motor.

In a multi-pole multi-phase linear DC brushless motor, each armature coil has an N pole of a field magnet,
In order to obtain a thrust in a predetermined direction corresponding to the S-pole, it is necessary to pass a current in a corresponding direction. In order to determine the current direction, each armature coil is provided with a position detecting element such as a hall element, a hall IC or a magnetoresistive element.

Unlike the case where the armature and the field magnet have an endless structure like a rotary motor, such a position detecting element is characterized in that either the armature or the field magnet is short. Above all, if the motor is arranged according to the same idea as the rotary motor, a linear DC brushless motor having a smooth thrust ripple characteristic cannot be obtained.

This is described in "Linear servomotor and system design" (Shiraki, Miyao, Sogo Denshi Publishing, Showa 6).
It has been announced in the material of the Linear Drive Study Group of the Institute of Electrical Engineers of Japan (issued in March 1st).

Regarding the arrangement of the position detecting element, it is a basic idea of the linear DC motor and the rotating motor that the position detecting element is arranged at a position facing the effective conductor portion that contributes to the thrust (torque) generated by the armature coil. Is.

However, disposing the position detecting element at a position facing the effective conductor portion that contributes to the thrust (torque) generated by the armature coil and at a position facing the field magnet makes it difficult to position the armature coil on the armature coil surface. In addition to arranging a printed circuit board and other troublesome means, the air gap between the field magnet and the armature coil must be formed longer by the thickness of the position detecting element, and the thrust force is correspondingly increased. There is a drawback in that (torque) is reduced.

Therefore, in the case of a rotary motor, because of the endless structure, an effective conductor that contributes to the generation of torque in the armature coil at a position in phase with the effective conductor portion that contributes to the generation of torque in the armature coil. It is arranged at a position that does not face the portion, for example, at an internal position of the armature coil. In the case of a rotary DC brushless motor, a linear DC
Unlike brushless motors, the armature side is always the stator and the field magnet is the rotor, whereas in the case of a linear DC brushless motor, the field magnet or Any of the armatures can be a mover and also a stator.

Further, in the case of a linear DC brushless motor, either the armature or the field magnet is short, so that the armature is arranged in accordance with the concept of the method for arranging the position detecting element of the rotary motor. If it is placed at a position that does not face the effective conductor part that contributes to the thrust generation of the armature coil at a position in phase with the effective conductor part that contributes to the thrust generation of the coil,
There is a drawback that the position sensing element does not detect the field magnet, and thrust is not generated depending on the armature coil equipped with the position sensing element. Further, as described above, in the case of the linear DC brushless motor, there is a drawback that the thrust ripple characteristic is deteriorated and smooth running cannot be performed.

Therefore, in the case of a linear DC brushless motor, other than the above-mentioned arrangement method of the position detecting element,
The conductor part that contributes to the thrust generation of the armature coil is arranged at a position where the extended armature coil does not exist, or the side opposite to the field magnet facing the effective conductor part that contributes to the thrust generation of the armature coil. A through hole is formed at the yoke position, and the position detecting element is housed in the through hole.

According to the former method, the width of the field magnet must be increased up to the extended position of the position detecting element so that the position can be surely detected, resulting in a wide linear DC brushless motor and a space. However, according to the latter method, a cogging torque is generated by the through hole when the field magnet passes, so that the air-core type armature coil However, there is a drawback that the advantage of the linear DC brushless motor having a coreless structure that uses the above-mentioned is that the smooth running is possible is negated.

As a solution to the above-mentioned drawbacks, the applicant of the present invention has previously proposed a linear DC shown in FIG.
There is a brushless motor. This linear DC brushless motor has a printed circuit board 14 'on the stator yoke 3'.
A stator armature 7'formed by arranging a group of armature coils 6'on its surface is fixed on the stator yoke 3'and configured to move relative to the field magnet 8 through a gap. .

In the armature coil 6 ', a deformed winding is formed by indenting a portion where the conductor portion 6'a or 6'b contributing to the generated thrust and the conductor portion 6'c not contributing to the generated thrust intersect inside. . The position sensing element 17 is located on the surface of the printed circuit board 14 'where the effective conductor portion 6'a or 6'b that contributes to the generated thrust intersects with the conductor portion 6'c that does not contribute to the generated thrust and the conductor portion does not exist. To be installed.

According to such a linear DC brushless motor, it is possible to solve the above-mentioned problems, but the deterioration of thrust is accompanied only by the recessed portion of the armature coil 6 ', and the armature coil 6'having a deformed shape. Since it is difficult to wind, it is not possible to obtain a certain quality, and it is not very easy to dispose the position detecting element 17 in the recessed portion of the armature coil 6 ′. It still had problems.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cogging torque even if a position detecting element is housed at a yoke position on a surface opposite to a field magnet facing an effective conductor portion that contributes to thrust generated by an armature coil. Linear D that enables smooth running without generating noise
The challenge was to obtain a C brushless motor.

Another object is to prevent the thrust from being reduced even if the above is performed.

[0016]

SUMMARY OF THE INVENTION An object of the present invention is to provide a yoke member provided with an armature with a long groove-shaped position detecting element accommodating groove extending along the longitudinal direction thereof. The position detecting element is provided at a position facing the conductor portion that contributes to the thrust generated on the surface of the armature coil opposite to the surface facing the field magnet, and the position detecting element is housed in the groove. Can be achieved.

Another problem is that the position detecting element housing groove is
This can be achieved by forming the armature coil at the position of the yoke member facing the conductor portion that does not contribute to the thrust generated by the armature coil.

[0018]

According to the linear DC brushless motor of the present invention, the effective conductor portion 6 that contributes to the thrust generated by the armature coil 6 is used.
The position detecting element 17 is housed at the position 3 of the surface stator on the side opposite to the field magnet 8 that faces a or 6b (including the conductor portion that intersects the conductor portion 6c or 6d that does not contribute to the generated thrust). Even if it is provided, the position detecting element housing groove 1 is a long groove formed in the stator yoke 3 at such a position.
Since there are two, the position detecting element 17 can be accommodated and arranged in the accommodating groove 12, but the position detecting element accommodating groove 12 is a break for generating a cogging torque between both ends in the longitudinal direction of the stator yoke 3. Since there is no cogging torque, the shape is such that cogging torque is not generated, and therefore the stator armature 7 and the field magnet 8 relatively smoothly travel.

[0019]

Examples of the invention

First Embodiment FIG. 1 shows a linear DC brushless motor according to a first embodiment of the present invention. FIG. 4 is an exploded perspective view of the main part of FIG. 4, and FIG. 4 is a bottom perspective view of the armature.

A stud 2 is planted on a long plate-shaped base 1 to mount and fix a long plate-shaped stator yoke 3 on the stud 2. The stator yoke 3 is formed with a mountain-shaped guide rail projection 5 which engages with the roller 4 so that the roller 4 slides on both side surfaces so as to also serve as a linear guide.

An insulating layer (not shown) such as paint is formed on the upper surface of the stator yoke 3, and n is formed through this insulating layer.
(N is an integer of 2 or more) m air core type armature coils 6 are arranged side by side along the longitudinal direction of the stator yoke 3 so as not to overlap each other, and m (m is an integer of 2 or more) phases. The stator armature 7 having the coreless structure is formed and is moved relative to the field magnet 8 described later.

On the upper surface of the field magnet 8, a long plate-shaped moving yoke 9 having a width wider than the width of the field magnet 8 is provided for closing the magnetic path of the field magnet 8. In order to make the field magnet 8 travel relative to the stator armature 7, studs 10 extending downward are planted on both side surfaces of the moving yoke 9, and the stud 10 is rolled. 4 is rotatably mounted, the roller 4 is rotatably engaged with the protrusion 5, and the roller 4, the stud 10, the moving yoke 9 and the field magnet 8 are moved. Child 11
Is moved relative to the stator armature 7 along the longitudinal direction of the stator yoke 3.

A position detecting element accommodating groove 12 extending in the longitudinal direction is formed in the center portion of the stator yoke 3.
The groove 12 further widens the open end to form an engaging step 13. The lateral width of the engagement step portion 13 is made to match the width of the printed circuit board 14 described later.

On the lower surface of the armature coil group 6, a long printed board 14 having a printed wiring pattern (not shown) is fixed by means of an adhesive or the like.

The printed circuit board 14 is a double-sided through-hole circuit board, and both terminals 15 of the armature coil 6 are guided to the lower surface of the printed circuit board 14 via solder 16 and soldered to the lower surface of the printed circuit board 14. The output terminal of the position detecting element 17 is electrically connected.

The position detecting element 17 is made to face the position detecting element housing groove 12, and the printed board 14 is embedded in the position detecting element housing groove 12 by the adhesive applied to the engagement step portion 13. In this case, the depth of the engaging stepped portion 13 is designed to be an optimum value so that the printed circuit board 14 surface and the stator yoke 3 surface become a uniform flat surface.

In order to form an efficient linear DC brushless motor, the air-core type armature coil 6 has an effective conductor portion 6a which contributes to the generated thrust extending in the direction perpendicular to the running direction of the field magnet 8. The open angle widths of 6 and 6b are matched with the width T of one magnetic pole of the field magnet 8 to form a rectangular frame shape, and contribute to the generated thrust extending in the direction perpendicular to the traveling direction of the field magnet 8. Length L of effective conductors 6a and 6b
And the length L of the field magnet 8 are the same as a rectangular frame.

The conductor portions 6c and 6d extending in the direction parallel to the traveling direction of the field magnet 8 are conductor portions that do not contribute to the generated thrust. Therefore, in a large-sized linear DC brushless motor, since it is formed at a low cost, the width is short so that the field magnet 8 is not opposed to the portion opposed to the width Lb of the conductor portions 6c and 6d that does not contribute to the generated thrust. The field magnet 8 is used. That is, the field magnet 8
Has a length extending in a direction perpendicular to the traveling direction of the field magnet 8 to a length width of (L-2Lb) = La.

However, the conductor portions at the intersections of the effective conductor portions 6a and 6b contributing to the thrust generated by the armature coil 6 and the conductor portions 6c and 6d not contributing to the thrust are small in area and volume, Since it contributes to the generated thrust, it cannot be ignored in a small linear DC brassless motor.

Therefore, in this embodiment, the armature coil 6
The length L of the effective conductors 6a and 6b, which contributes to the generated thrust extending in the direction perpendicular to the traveling direction of the field magnet 8, is matched with the length L of the field magnet 8.

In FIG. 1, reference numeral 18 is a printed circuit board disposed on the lower surface of the stator yoke 3, and 19 is an electric component for the energization control circuit disposed on the printed circuit board 18.

[0032]

Second Embodiment of the Invention FIG. 5 shows a linear DC brushless motor according to a second embodiment of the present invention. FIG. FIG. 8 is an exploded perspective view of the main part, and FIG. 8 is a bottom perspective view of the armature.

The description overlapping with that of the first embodiment will be made by referring to the above-mentioned item, and only the different points will be explained. In the linear DC brushless motor of this second embodiment, the armature coil 6 will be described.
The position detecting element accommodating groove 12 is formed at the position of the stator yoke 3 which faces the conductor portion 6c which does not contribute to the generated thrust.

The printed board 14 is fixed to the surface opposite to the field magnet 8 facing the conductor portion 6c which does not contribute to the thrust generated by the armature coil group 6 facing the housing groove 12, and the lower surface of the printed board 14 is fixed. The position detecting element 17 is arranged at a position that meets the above conditions.

In this way, when the position detecting element housing groove 12 is formed at the position of the stator yoke 3 facing the conductor portion 6c which does not contribute to the thrust generated by the armature coil 6, the conductor portion 6c originally has Since the conductor portion hardly contributes to the generated thrust, the field magnet 8 is formed by the housing groove 12 at the position of the stator yoke 3 facing the conductor portion 6c.
Even if the space between the storage groove 12 and the storage groove 12 is increased by the length of the storage groove 12, there is an advantage that the thrust of the linear DC brushless motor is hardly affected.

[0036]

According to the present invention, in order to improve the thrust ripple characteristic, position detection is performed at the stator yoke position facing the most ideal conductor portion that contributes to the thrust generated by the armature coil. Even if the element is housed, the cogging torque is not generated by this, so that a linear DC brushless motor having an extremely smooth thrust ripple characteristic can be obtained.

Of course, as in the prior art, the width of the linear DC brushless motor is widened or the air gap between the field magnet and the stator yoke is formed long by arranging the position detecting element. It is possible to eliminate the drawback that the thrust is lowered.

Further, if the lead wire is passed through the groove for accommodating the position detecting element, the processing of the lead wire becomes extremely easy and the structure thereof can be simplified.

In the above embodiment, the movable field magnet type linear DC brushless motor having the field magnet side as the mover and the armature side as the stator is shown. However, the field magnet side is used as the stator, It goes without saying that a movable armature-type brushless DC brushless motor having the armature side as a moving element may be used.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a linear DC brushless motor according to a first embodiment of the present invention, as seen from the traveling direction of a moving element.

2 and 3 are exploded perspective views of a main part of FIG. 1.

FIG. 4 is a bottom perspective view of the armature.

FIG. 5 is a vertical cross-sectional view showing a linear DC brushless motor according to a second embodiment of the present invention, as viewed from the traveling direction of a moving element.

6 and 7 are exploded perspective views of the main part of FIG. 5.

FIG. 8 is a bottom perspective view of the armature.

FIG. 9 is an exploded perspective view of a main part of a conventional linear DC brushless motor.

[Explanation of symbols]

1 base 2 stud 3,3 'stator yoke 4 roller 5 guide rail projection 6,6' armature coil 6a, 6'a, 6b, 6'b effective conductor portion 6c that contributes to thrust , 6'c, 6d Conductor that does not contribute to the generated thrust 7, 7'Steater armature 8 Field magnet 9 Moving yoke 10 Stud 11 Mover 12 Position detection element storage groove 13 Engagement step 14 Print Substrate 15 Terminal 16 Solder 17 Position detection element 18 Printed circuit board 19 Electrical components for energization control circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masazumi Morishita 2-3-13, Azuchi-cho, Chuo-ku, Osaka-shi, Osaka, Osaka International Building Minolta Camera Co., Ltd. (72) Makoto Izawa Azuchi, Chuo-ku, Osaka-shi, Osaka 2-13-3 Machi, Osaka International Building Minolta Camera Co., Ltd.

Claims (2)

[Claims] 1. N is so arranged that adjacent magnetic poles have different polarities.
Relative travel of a field magnet having P (P is an integer of 2 or more) magnetic poles and S poles and an armature having one or more air-core armature coils through the field magnet and a gap. In the linear DC brushless motor, the armatures are arranged so as to oppose each other, and the position detection element is provided at a position opposed to the effective conductor portion that contributes to the thrust generated by the armature coil on the armature side. The yoke member is provided with a long groove-shaped position detecting element accommodating groove extending along the longitudinal direction of the yoke member, and the accommodating groove is provided with a thrust generated on a surface of the armature coil opposite to the surface facing the field magnet. A linear DC brushless motor characterized in that the position detecting element is provided at a position opposed to a contributing conductor portion, and the position detecting element is housed in the housing groove. 2. The linear DC brushless motor according to claim 1, wherein the position detecting element accommodating groove is formed at a position of a yoke member facing a conductor portion that does not contribute to the thrust generated by the armature coil. -Ta.