JP2004320959A - Linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a linear motor in which the size can be reduced without sacrifice of the effective stroke of a moving member and erroneous operation of a Hall sensor can be prevented. <P>SOLUTION: In the linear motor with the Hall sensor, end part of the surface of a permanent magnet 1 facing an armature is inclined by a specified angle, and a Hall sensor 5 is placed in leakage flux entering from the end part of the permanent magnet 1 such that the leakage flux is spread outward of a magnetic circuit formed between the permanent magnet and the armature. Since the Hall sensor 5 is disposed perpendicularly to the permanent magnet 1 and not disposed in the moving direction of a moving element, effective stroke is not sacrificed. Furthermore, the Hall sensor can be disposed without sacrifice of a magnetic air gap because leakage flux from the end part of the permanent magnet spreads outward. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a structure of a linear motor used for a feed mechanism of a machine tool or a positioning device of a semiconductor manufacturing apparatus and having a magnetic pole detection function using a Hall sensor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, linear motors that are used in a feed mechanism of a machine tool or a positioning device of a semiconductor manufacturing apparatus and have a magnetic pole detection function using a Hall sensor have been disclosed as first and second prior arts. Hereinafter, the prior art will be described with reference to FIGS. 3 and 4, respectively. In the drawing, the field constituting the stator of the linear motor is not shown, and only the armature constituting the mover is shown.
FIG. 4 is a side view of a linear motor armature showing the first prior art, and is a perspective view of the inside. Here, in FIG. 4 exemplifying an armature configured as a mover, 11 is an armature winding, 12 is a resin mold, 13 is an armature base, 14 is a Hall sensor, and 15 is a Hall sensor substrate. .
The armature has an air core portion and is composed of a plurality of coil groups, and includes an armature winding 11 formed in a flat plate shape, and an armature base 13 for attaching the armature to another device such as a table. The armature winding 11 is fixed with a resin mold 12 around the air core and the coil group. Further, a Hall sensor 14 for detecting a magnetic pole by a magnetic flux generated from a field constituting a stator (not shown) is mounted on a Hall sensor substrate 15 on a stroke end surface of the armature.
FIG. 5 is a side view of a linear motor armature showing a second prior art, and the inside is seen through.
The second prior art differs from the first prior art in that the Hall sensor 14 for detecting the magnetic pole is not provided outside the armature, but is provided in the air core portion of the armature winding 11 ( For example, see Patent Document 1).
[0003]
[Patent Document 1]
Real Registration No. 2596793 [0004]
[Problems to be solved by the invention]
However, the conventional method has the following problems.
(1) In the first prior art, since the Hall sensor unit projects in the stroke direction of the mover, the effective stroke is sacrificed by the projection of the Hall sensor. In other words, the length of the mover or the size of the motor in the stroke direction is limited. For example, it cannot be applied to the use of a linear motor mounted on a bonder or the like, and is not suitable for miniaturization.
(2) Further, as in the second prior art, a structure in which a Hall sensor is installed in an air core portion of an armature winding. Since the Hall sensor is disposed immediately adjacent to the armature winding, the Hall sensor flows through the armature winding. An AC magnetic field is generated by the current, and the Hall sensor malfunctions under the influence of the AC magnetic field.
[0005]
The present invention has been made to solve the above problems, and provides a linear motor that can be miniaturized without sacrificing an effective stroke of a mover and that can prevent a malfunction of a Hall sensor. The purpose is to:
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention according to claim 1 has a plurality of permanent magnets arranged alternately in a line so as to have different polarities, and a magnetic field and a magnetic gap. An armature having an armature winding composed of a plurality of coil groups disposed opposite to each other, and a Hall sensor having a magnetic pole detection function disposed on the armature, wherein one of the field and the armature is fixed. In the linear motor, the other end of the surface facing the armature of the permanent magnet is inclined by a predetermined angle, and the end of the permanent magnet The Hall sensor is installed in the leakage magnetic flux so as to spread the leakage magnetic flux incident from outside the magnetic circuit formed between the permanent magnet and the armature.
According to a second aspect of the present invention, in the linear motor according to the first aspect, the Hall sensor is provided in a direction perpendicular to the permanent magnet.
According to a third aspect of the present invention, in the linear motor according to the first or second aspect, an armature base for mounting a table for conveying an object to the armature is provided, and the Hall sensor is mounted on the armature. It is provided inside the base.
By the above means, the end of the surface of the permanent magnet facing the armature is processed so as to be inclined by a predetermined angle, and when the Hall sensor is installed in a direction perpendicular to the flat permanent magnet, Since the armature winding is also installed perpendicularly, the influence of the AC magnetic field generated from the energized armature winding can be reduced. Therefore, the Hall sensor can be installed without sacrificing the effective stroke, and malfunction of the Hall sensor can be prevented.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a side view of a linear motor showing a first embodiment of the present invention, and FIG. 2 is a front sectional view of the linear motor taken along line AA in FIG. 1, showing a Hall sensor mounting portion. is there.
In the figure, 1 is a permanent magnet, 2A is an outer yoke, 2B is an inner yoke, 2C is a fixed yoke plate, 3 is an armature winding, 4 is an armature mounting block, 5 is a Hall sensor, 6 is a Hall sensor board, Reference numeral 7 denotes a resin mold.
The features of the present invention are as follows.
The linear motor is of a moving coil type constituted by an armature forming a mover and a field arranged via the armature and a magnetic gap, and one field is a side surface as shown in FIG. The shape of the yoke as seen from is the shape of the sun. More specifically, the field includes two flat outer yokes 2A, an inner yoke 2B arranged between the outer yokes 2A, and a yoke fixing plate 2C connecting both ends of the outer yokes 2A and the inner yokes 2B. It is composed of a field yoke and a plurality of flat permanent magnets 1 arranged linearly on the outer yoke 2A so as to alternately have different polarities.
The other armature is composed of an armature winding 3 composed of a plurality of coil groups having an air core, and an armature mounting block 4 provided on both sides of the armature winding 3. It is formed in the shape of. The armature has a structure in which the inner yoke 2B penetrates the air core portion of the armature winding 3 and the outer upper and lower ends of the armature winding 3 are sandwiched by the outer yoke 2A. The armature winding 3 and the armature mounting block 4 are fixed with a resin mold 7.
It should be noted that the end of the surface of the permanent magnet 1 facing the armature is inclined by a predetermined angle, and the leakage magnetic flux incident from the end of the permanent magnet 1 is transmitted to the permanent magnet and the electric motor. The point is that the Hall sensor 5 is installed on the Hall sensor substrate 6 provided at the end of the armature mounting block 7 in which the leakage magnetic flux is spread so as to spread outside the magnetic circuit formed between the Hall sensor 5 and the armature. Here, the Hall sensor 5 is provided in a direction perpendicular to the permanent magnet 1.
Note that the armature, which is a mover, is supported by a linear guide or the like including a slider and a guide rail, not shown.
[0008]
Next, the operation will be described.
In a linear motor, a predetermined current corresponding to the electrical relative position of the armature and the field is caused to flow through the armature winding to act on the magnetic field created by the permanent magnet to generate thrust on the armature. It will move in the traveling direction. At this time, the leakage magnetic flux incident from the magnet end is formed between the permanent magnet and the armature by the permanent magnet and the Hall sensor having the end of the surface facing the armature inclined at a predetermined angle. Spread outside of the magnetic circuit.
[0009]
As described above, in the linear motor according to the first embodiment of the present invention, the end of the surface of the permanent magnet 1 facing the armature is inclined by a predetermined angle, and the leakage magnetic flux incident from the end of the permanent magnet 1 is reduced. A Hall sensor 5 is installed in the leakage magnetic flux so as to extend outside a magnetic circuit formed between the permanent magnet and the armature, and the Hall sensor 5 is disposed in a direction perpendicular to the permanent magnet 1. Since the Hall sensor is not provided in the moving direction of the mover, the effective stroke is not sacrificed. Further, since the leakage magnetic flux from the end of the permanent magnet spreads outward, the Hall sensor can be installed without sacrificing the magnetic air gap.
[0010]
(Second embodiment)
Next, a second embodiment of the present invention will be described.
FIG. 3 is a sectional view of a linear motor showing a second embodiment of the present invention. The linear motor is of a magnetic flux penetrating type in which fields are arranged on both sides of the armature, and is a moving coil type as in the first embodiment. The description of the components of the second embodiment which are the same as those of the prior art and the first embodiment will be omitted.
In FIG. 3, 8 is a permanent magnet, 9 is a yoke, and 10 is a Hall sensor.
The second embodiment is different from the prior art and the first embodiment in that the armature winding 11 is formed in a plate shape in which the armature is composed of a plurality of coil groups, and another device such as a table for transporting an object. And the armature base 13 for attaching the armature to the armature, and the hall sensor 10 is provided inside the armature base 13.
Since the second embodiment of the present invention is configured as described above, the magnetic air gap between the armature and the field is not sacrificed, and the linear motor can be reduced in size.
[0011]
In the above embodiments, the linear motor having the structure in which the stator is the field and the mover is the armature has been described. However, the structure may be such that the stator is the armature and the mover is the field.
In addition, although the shape of the armature is a mouth shape, it goes without saying that the present invention is also applicable to a concave shape or a structure in which permanent magnets are simply arranged on one side.
[0012]
【The invention's effect】
As described above, the present invention has the following effects.
(1) The end of the surface of the permanent magnet facing the armature is inclined by a predetermined angle, and leakage magnetic flux incident from the end of the permanent magnet is formed between the permanent magnet and the armature. A Hall sensor is installed in the leakage magnetic flux so as to extend outside the magnetic circuit, and the Hall sensor is provided in a direction perpendicular to the permanent magnet, so that the Hall sensor is not installed in the moving direction of the mover. Therefore, the effective stroke is not sacrificed. Further, since the leakage magnetic flux from the end of the permanent magnet spreads outward, the Hall sensor can be installed without sacrificing the magnetic air gap.
(2) Since the Hall sensor is installed perpendicular to the armature winding, the effect of the AC magnetic field generated by the current flowing through the armature winding can be reduced, and malfunction of the Hall sensor can be prevented.
(3) Since the Hall sensor is provided inside the armature base, the magnetic air gap between the armature and the magnetic field is not sacrificed, and the linear motor can be reduced in size.
[Brief description of the drawings]
FIG. 1 is a side view of a linear motor according to a first embodiment of the present invention.
FIG. 2 is a front sectional view of the linear motor taken along the line AA in FIG. 1, showing a Hall sensor mounting portion.
FIG. 3 is a sectional view of a linear motor showing a second embodiment of the present invention.
FIG. 4 is a side view of a linear motor armature showing a first related art.
FIG. 5 is a side view of a linear motor armature showing a second related art.
[Explanation of symbols]
1, 8 permanent magnet 2A outer yoke 2B inner yoke 2C yoke fixed plate 3, 11 armature winding 4 armature mounting block 5, 10 hall sensor 6 hall sensor board 7 12 resin mold 9 yoke 13 armature base

Claims (3)

An electric machine having a field in which a plurality of permanent magnets are alternately arranged linearly so as to have different polarities, and an armature winding composed of a plurality of coil groups and opposed to the field with a magnetic gap therebetween. Armature and a Hall sensor having a magnetic pole detection function disposed on the armature, wherein one of the field and the armature runs as a stator and the other moves relative to a mover. At
The end of the surface of the permanent magnet facing the armature is inclined by a predetermined angle,
The Hall sensor is provided in the leakage magnetic flux so that a leakage magnetic flux incident from an end of the permanent magnet is spread outside a magnetic circuit formed between the permanent magnet and the armature. Linear motor. The linear motor according to claim 1, wherein the Hall sensor is provided in a direction perpendicular to the permanent magnet. 3. The linear motor according to claim 1, wherein an armature base for mounting a table for transporting an object to the armature is provided, and the Hall sensor is provided inside the armature base.

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