JP4438372B2 - Moving magnet type linear actuator - Google Patents

Description

  The present invention relates to a linear actuator suitable for driving a linear motion mechanism, for example, used in various industrial machines such as an electrical component mounting apparatus, a semiconductor-related apparatus, or a machine tool. The present invention relates to a moving magnet type linear actuator having an armature as a stator.

Conventionally, a linear actuator that is used in various industrial machines such as an electrical component mounting apparatus, a semiconductor-related apparatus, or a machine tool, and suitable for driving the linear motion mechanism is shown in FIG. 3 is a movable magnet type linear actuator showing the prior art, in which (a) is a plan view thereof, (b) is a front sectional view taken along the line BB of (a), This corresponds to a view seen through from the arrow A in (b).
In FIG. 3, 1 is an armature, 2 is a stator base, 3 is a field permanent magnet, 4 is a field yoke, 6 is a linear guide rail, 7 is a sensor, 8 is a linear guide block, 9 is a linear scale section, 11 is a coil, 12 is a wiring board, and 13 is a stopper.
In the linear actuator, a field yoke 4 is provided on the back surface of the field permanent magnet 3, and the field yoke 4 serves both as a mover and a magnetic circuit. The armature 1 has a structure including a plurality of slotless coils 11, and is disposed on a stator base 2 made of a solid magnetic member via a mover and a magnetic gap so that the stator is It is composed. Parallel linear guide rails 6 are fixed on the stator base 2 on both sides of the armature 1, and linear guide blocks 8 that slide on the rails are arranged on the linear guide rail 6. It is fixed at the bottom of both ends. Further, a magnetic linear scale 9 constituting a linear encoder is disposed on the side surface of the mover, and a sensor 7 for detecting the linear scale 9 on the stator base 2 so as to face the linear scale 9. Is arranged. Then, a stopper 13 is provided between the ends of the two linear guide rails 6 to prevent the overrun of the mover.
This linear actuator has a magnetic circuit structure in which the magnetic flux of the field permanent magnet 3 is linked to the stator base 2. When the armature coil 11 is excited, the linear actuator is moved by the field and the armature. The mover is linearly moved by a magnetic field within a stroke which is the difference between the armature length and the mover length (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 9-266659 (Specification, page 5, FIG. 3)

However, in the prior art, since the stator base is composed of a solid magnetic member, the electric resistance of the member is small, so that when the mover having a field permanent magnet moves in the sliding direction, the stator The eddy current loss generated in the base has increased, and there have been problems such as deterioration in accuracy due to temperature rise of the stator base and reduction in actuator efficiency due to increase in viscous friction. This problem is particularly noticeable when high-frequency acceleration / deceleration operations are performed.
The present invention has been made to solve the above-described problems, and reduces eddy current loss on the stator base side caused by moving a field permanent magnet, which is a mover, and increases the temperature of the stator base. It is an object of the present invention to provide a movable magnet type linear actuator capable of preventing the accompanying accuracy deterioration and increase in viscous friction.

In order to solve the above-described problem, the invention of a movable magnet type linear actuator according to claim 1 includes a stator base, an armature fixed to the stator base and mounted with a plurality of coil groups, and the armature. A linear guide rail linearly arranged so as to sandwich both sides of the armature, and a field magnet disposed opposite to the armature via a magnetic gap and fixed on the field yoke A mover having a field made of a permanent magnet, a linear guide block provided so as to slide on the linear guide rail, and an optical linear scale disposed on a side surface of the field yoke; And an optical encoder that is disposed on the stator base side so as to face the linear scale and detects the linear scale, and the movable element with respect to the stator In the movable magnet type linear actuator that detects the position in the sliding direction by the optical encoder, the stator base has a thin plate-like electromagnetic wave in a direction perpendicular to the moving direction of the mover so as to face the armature. It is characterized in that a core made of laminated steel plates is embedded .
According to a second aspect of the present invention, in the movable magnet type linear actuator according to the first aspect, a refrigerant conduit or a forced liquid cooling jacket is embedded in the stator base.
According to a third aspect of the present invention, in the movable magnet type linear actuator according to the first or second aspect, the stator base material is made of aluminum or an aluminum alloy, titanium or a titanium alloy, or a nonmagnetic material of magnesium or a magnesium alloy. Any one of them is used.

According to the first aspect of the present invention, the moving direction of the mover is in the recess having the same length as the entire length of the coil disposed on the stator base and the same width as the width of the field permanent magnet 3. The core made by laminating thin electromagnetic steel sheets in a direction perpendicular to the armature is embedded so as to face the armature, so that the electric resistance of the stator portion increases and the field permanent magnet that is the mover is fixed. It is possible to reduce the eddy current loss caused by moving on the child and interlinking of the magnetic field flux, and the effect of reducing the iron loss at high speed can be improved.
In addition, according to the second aspect of the present invention, a forced cooling structure such as liquid cooling can be used for the heat generating portion gathered at one place on the stator side, and the cooling performance of the actuator can be improved.
According to the invention described in claim 3, since the member such as aluminum is used for the stator base, the actuator can be reduced in weight as compared with the prior art.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a movable magnet type linear actuator showing a first embodiment of the present invention, in which (a) is a plan view thereof, (b) is a front sectional view taken along line BB of (a), a) corresponds to a view seen through from the arrow A in (b). Note that the description of the same constituent elements of the present invention as those of the prior art will be omitted, and only different points will be described.
In FIG. 1, 10 is a core.
The features of the present invention are as follows.
That is, the stator of the linear actuator is provided so as to face the armature 1, the stator base 2, the armature 1 fixed to the stator base 2 and mounted with a plurality of coil groups 11, and the stator. It is embedded in the recess 2A provided so as to have the same length as the entire length of the coil disposed on the base 2 and the width of the field permanent magnet 3, and is perpendicular to the moving direction of the mover. And a linear guide rail 6 linearly arranged so as to sandwich both sides of the armature 1, and the mover is the armature 1. Field permanent magnets which are arranged opposite to each other via a magnetic gap and are fixed on a flat field yoke 4 and have a plurality of magnetic poles alternately different from N poles, S poles, etc. 3 field and slide on the linear guide rail 6 A point having a linear guide block 8 provided to so that.
A linear scale 9 constituting an optical encoder is disposed on the side surface of the field yoke 4, and a sensor 7 for detecting the linear scale 9 is arranged on the stator base 2 side so as to face the linear scale 9. It is installed.
The material of the stator base 2 is basically a magnetic material such as iron, but aluminum or an aluminum alloy is preferable in order to reduce the weight, and other materials such as titanium or a titanium alloy, magnesium or a magnesium alloy, etc. Any of non-magnetic materials may be used.
In such a configuration, the present linear actuator has a smaller number of field magnetic poles than the number of magnetic poles of the magnetomotive force generated in the armature, and the difference becomes a stroke on the movable side of the linear actuator, and performs linear movement.
Therefore, the movable magnet type linear actuator according to the present embodiment is provided in the concave portion 2A having a length equivalent to the entire length of the coil arranged on the stator base 2 and a dimension equivalent to the width dimension of the field permanent magnet 3. Since the core 10 formed by laminating thin electromagnetic steel plates in a direction perpendicular to the moving direction of the mover is embedded so as to face the armature 1, the electric resistance of the stator portion increases, and the mover It is possible to reduce the eddy current loss due to the field permanent magnet moving on the stator and interlinking of the field magnetic flux, and the effect of reducing the iron loss at high speed can be increased. As a result, it is possible to solve problems such as accuracy deterioration due to temperature rise of the stator base 2 and reduction in actuator efficiency due to increase in viscous friction.
In addition, since a lighter member such as aluminum can be used for the stator base, the actuator can be lighter than the prior art.

Next, a second embodiment of the present invention will be described.
FIG. 2 is a movable magnet type linear actuator showing a second embodiment of the present invention, in which (a) is a plan view thereof, (b) is a front sectional view taken along line BB of (a), a) corresponds to a view seen through from the arrow A in (b).
In FIG. 2, 5 is a refrigerant conduit.
The second embodiment is different from the first embodiment as follows.
In other words, the refrigerant base 5 is embedded in the stator base 2.
In the second embodiment, since the refrigerant conduit 5 is embedded in the stator base 2, the heat generating part concentrated in one place of the stator can be efficiently obtained by forcing cooling through the refrigerant conduit. It becomes possible to cool, and the cooling performance of the actuator can be improved.
It is also possible to purchase a refrigerant conduit and to have a structure in which a forced liquid cooling jacket is embedded in the stator base 2.

BRIEF DESCRIPTION OF THE DRAWINGS It is a movable magnet type | mold linear actuator which shows 1st Example of this invention, Comprising: (a) is the top view, (b) is a front sectional view in alignment with the BB line of (a), (a) is This corresponds to the view seen through from the arrow A in (b). It is a movable magnet type linear actuator which shows 2nd Example of this invention, Comprising: (a) is the top view, (b) is a front sectional view which follows the BB line of (a), (a) is This corresponds to the view seen through from the arrow A in (b). It is a movable magnet type linear actuator showing a prior art, wherein (a) is a plan view thereof, (b) is a front sectional view taken along line BB of (a), and (a) is an arrow of (b). This corresponds to a view seen through from the view A.

DESCRIPTION OF SYMBOLS 1 Armature 2 Stator base 2A Recess 3 Field permanent magnet 4 Field yoke 5 Cooling conduit 6 Linear guide rail 7 Sensor (linear scale detection part)
8 Linear guide block 9 Linear scale part 10 Core 11 Coil 12 Connection board 13 Stopper

Claims (3)

A stator having a stator base, an armature fixed to the stator base and mounted with a plurality of coil groups, and linear guide rails arranged in a straight line so as to sandwich both sides of the armature When,
A linear guide block that is disposed so as to face the armature through a magnetic air gap, and that is configured to slide on the linear guide rail, and a field composed of a field permanent magnet fixed on a field yoke. And a mover having
An optical linear scale disposed on a side surface of the field yoke, and an optical sensor facing the linear scale and disposed on the stator base side and detecting the linear scale. An encoder,
In the movable magnet type linear actuator that detects the position of the mover in the sliding direction with respect to the stator by the optical encoder,
A movable magnet characterized in that a core formed by laminating thin electromagnetic steel sheets in a direction perpendicular to the moving direction of the mover is embedded in the stator base so as to face the armature. Linear actuator.   2. The movable magnet type linear actuator according to claim 1, wherein a refrigerant conduit or a forced liquid cooling jacket is embedded in the stator base.   3. The movable magnet type linear actuator according to claim 1, wherein the stator base material is made of aluminum or an aluminum alloy, titanium or a titanium alloy, or a nonmagnetic material of magnesium or a magnesium alloy. .

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