JP2004072854A - Moving member for linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moving member for a linear motor capable of attaining desired precision by conducting reciprocating movement without any contact with a magnetic pole in which a coil forms a magnetic field in a movable range even if the coil is not regularly wound with a conductor in order. <P>SOLUTION: This moving member includes a cylindrical coil 1, an annular body 2 which is fixed so as to be brought into close contact with at least one end of the coil 1 and which uses an axis in common to the coil, a drive member 4 disposed at a position distant from the annular body 2 by a prescribed distance, and a jointing member 3 for jointing the annular body 2 with the drive member 4. A resin film layer 25 for retaining the coil 1 is provided on the inner periphery of the coil 1. The resin film layer 25 is constituted by forming a film formed made of, for example, polyimide resin into a cylindrical shape so as to meet the whole surface of the inner periphery of the coil 1, and is bonded to the inner periphery of the coil 1. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a linear motor mover particularly suitable for a linear motor used in a drive section of a linear compressor.
[0002]
[Prior art]
FIG. 3 shows a conventional linear motor. FIG. 4 is a sectional view of FIG. 3A part.
In FIG. 3, a cylindrical outer yoke 10 and an inner yoke 12 shorter than the outer yoke 10 are coaxially arranged, and one end of each is connected by a connecting yoke 20 made of the same material. In a gap between the outer yoke 10 and the inner yoke 12, a magnet 11 and a cylindrical coil 1 are disposed to face each other.
The magnet 11 is a permanent magnet divided into a plurality of pieces along the circumferential direction of the outer yoke 10, is disposed at an appropriate interval on the inner circumferential surface of the outer yoke 10, is attracted by a strong magnetic force, and is further bonded by an adhesive. Fixed. The coil 1 is incorporated in a support cylinder 15 described later and is integrated therewith, and is in a movable state without contacting the magnet 11 and the inner yoke 12.
[0003]
As shown in FIG. 4, the coil 1 is formed by winding a conductive wire 1A having a predetermined length around a bobbin, and is incorporated into a side portion of a support cylinder 15 formed of a non-magnetic metal or resin and integrally fixed with an adhesive or the like. Have been. When two or more sets of the coils 1 are used, the coils are incorporated and fixed integrally in a state where they are arranged in series in the axial direction on the side of the support tube 15.
[0004]
One end of the support cylinder 15 is connected to a cap 21 for closing the opening surface. The drive shaft 18 is inserted into a hole provided in the center of the cap 21 and fixed by welding. That is, the support cylinder 15 having the coil 1 built therein, the cap 21 and the drive shaft 18 are integrated to form a mover of the linear motor.
An end plate 10A is provided on the upper end surface of the outer yoke 10 in the drawing, and a drive shaft 18 is slidably inserted into a hole provided at the center thereof.
The support cylinder 15 is supported by the two coil springs 19 and 22 arranged on both sides of the cap 21 in a state of being always separated (floating) from the inner yoke 12 and the magnet 11.
[0005]
In the conventional linear motor configured as described above, for example, the cylinder 30 of the compressor to be driven is fixed to the end plate 10A of the outer yoke 10 by welding, and the drive shaft 18 is inserted into the cylinder 30 and attached as a piston. Used.
[0006]
[Problems to be solved by the invention]
By the way, the conventional techniques as described above have the following problems to be solved.
That is, as shown in FIG. 4, the coil 1 constituting the mover is formed by encapsulating a spirally wound conductor 1A with a resin and integrally molding it into a cylindrical shape. Not necessarily. For this reason, irregularities are formed on the outer peripheral surface of the resin covering the coil, and the shape is unstable. Therefore, the movable element may come into contact with the inner yoke 12 when reciprocating in the movable area.
As the conventional coil 1, there is also a coil 1 having a structure in which a conductor is wound around a bobbin having a flange, and the coil is covered with a resin so as to be integrated. However, the overall structure becomes large and heavy, and measures against eddy current are taken. There was a problem that it was necessary.
[0007]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a linear motor mover capable of performing a reciprocating motion without contacting a magnetic pole forming a magnetic field in a movable region and maintaining a desired accuracy.
[0008]
[Means for Solving the Problems]
The present invention employs the following configuration to achieve the above object.
[0009]
<Configuration 1>
A coil formed by covering a spirally wound conductive wire with a resin and molding it into a cylindrical shape, an annular body fixed to the end of the coil and having a common axis with the coil, and moving away from the coil Direction, a driving member disposed at a position separated from the annular body by a predetermined distance, a connecting member connecting the annular body and the driving member, and the driving member so that the coil can reciprocate in a movable region. What is claimed is: 1. A movable element for a linear motor, comprising: a movable shaft having a drive shaft for movably supporting, wherein a resin film layer for holding the coil is provided on an inner periphery of the coil.
[0010]
The coil, the annular body, the connecting member, and the driving member form a mover integrally with a common axis, and are driven by electromagnetic force to perform a predetermined reciprocating motion.
The coil is an electric coil, for example, has a cylindrical shape wound by a solenoid, and may have a circular or polygonal cross section. The coil may be single-layered or multi-layered.
The resin film layer stabilizes the shape of the coil, suppresses the generation of eddy currents, and promotes the weight and size of the coil.
[0011]
The annular body reinforces the coil and is attached to the driving member. The annular body may be in close contact with the entire end of the coil or may be in close contact with a part thereof. The material of the annular body is arbitrary, and a metal or a synthetic resin can be used. However, in the case of a metal, a nonmagnetic material such as stainless steel or aluminum is preferable because it is placed in a magnetic field. The cross-sectional shape of the annular body is preferably substantially the same as that of the coil. Since it comes into contact with the wall, it has an effect of preventing contact between the coil and the surrounding wall, thereby preventing a short circuit accident.
[0012]
The driving member is arranged at a position separated by a predetermined distance in a direction away from the coil, in order to arrange the driving member as far as possible from the magnetic field.
When the connecting member is cylindrical, a plurality of through holes are provided within a range that does not impair the mechanical strength, or when the connecting member is not cylindrical, by forming a plurality of rods, at the same time as suppressing the generation of eddy current, Lighter weight and easier heat dissipation.
[0013]
Eddy currents cause heat generation and energy loss, and others exert an electromagnetic force in a direction that hinders the movement of the coil. It is preferable to select the material and shape of the annular body and the connecting member so as to effectively suppress one or both of them.
The driving member is connected to a load by any means and transmits driving force to the outside.
[0014]
<Configuration 2>
2. The mover for a linear motor according to Configuration 1, wherein the resin film layer is made of a polyimide resin.
[0015]
The polyimide resin has good electrical insulation and heat resistance, is mechanically strong, and is formed to conform to the inner peripheral surface of the coil to hold the coil steadily.
[0016]
<Configuration 3>
2. The mover for a linear motor according to Configuration 1, wherein the annular body is made of metal and has a slit that cuts off electrical continuity in a circumferential direction.
[0017]
The annular body moves between magnetic poles constituted by magnets and yokes or very close to the magnetic poles. The slit prevents eddy currents generated in the circumferential direction of the annular body at that time, or increases the resistance to the eddy currents. The slit may be partially void, or an insulator may be interposed between the slits. A plurality of slits may be provided, and the shape and width of the slit are arbitrary.
[0018]
<Configuration 4>
In the linear motor mover according to Configuration 1, the driving member includes a board having a center on an extension of the axis of the coil, and an end fixed to the center of the board to drive the coil in the axial direction. A mover for a linear motor, comprising a drive shaft for transmitting a force to the outside.
[0019]
When the coil moves in the axial direction and outputs its driving force, it is preferable to fix one end of the drive shaft on an extension of the axis of the coil. The reason why the drive member is provided with a disk having a center on the extension of the axis of the coil is to fix the drive shaft at the center. If the cross-sectional shape of the coil is a perfect circle, the disk is preferably disk-shaped.
[0020]
<Configuration 5>
2. The linear motor movable element according to claim 1, wherein the driving member is supported by an elastic member to apply a return force to the axial reciprocation of the coil. Child.
[0021]
An elastic force is applied to the driving member, which is mechanically stronger than the other parts, by an elastic member. When a return force against the axial reciprocation of the coil is applied to the driving member by an elastic member such as a coil spring, the coil is resonated at a predetermined amplitude.
In addition, the drive member is supported from both sides by two elastic members having substantially the same dimensions, so that the drive member can be supported in a well-balanced manner.
One end of the elastic member may be fixed to the driving member, or may be merely in contact with the driving member. As the elastic member, a coil spring having a small spring constant is preferable, but a leaf spring of any shape may be used. Since the annular member and the driving member are connected by the rod-shaped connecting member to reduce the weight, the elastic member can be reduced in size and weight.
[0022]
<Configuration 6>
The movable body for a linear motor according to Configuration 1, wherein the annular body includes an annular portion fixed to an end surface of the coil, and a tubular portion extending in an inner surface direction of the end of the coil. Mover for linear motor.
[0023]
A tubular portion was provided on the annular portion in order to make the annular portion closely adhere to the end face of the coil and firmly fix it. The tubular portion is disposed at the winding core portion at the end of the coil, and enhances the adhesion when the annular portion is fixed to the coil.
The tubular portion has a length sufficiently shorter in the axial direction than the entire length of the coil in the axial direction. The tubular portion enhances the adhesion when the annular portion is fixed to the coil, but the shorter the tubular portion, the lighter the weight. Further, it is necessary that the length of the cylindrical portion does not collide with the inner yoke constituting the magnetic pole when the coil reciprocates in the axial direction. Therefore, the length is set to be sufficiently short in the axial direction. Specifically, 20% or less of the entire length of the coil is preferable.
[0024]
<Structure 7> In the mover for a linear motor according to Structure 1, the coil includes a first coil and a second coil which have a common axis and are spaced apart in the axial direction. A mover for a linear motor.
[0025]
Two or more coils may be provided in series for one linear motor mover.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of a mover for a linear motor according to the present invention in a state where it is arranged between magnetic poles of the linear motor. 2A and 2B show an annular body used in the embodiment of the present invention. FIG. 2A is a plan view, FIG. 2B is a longitudinal sectional view along AA in FIG. 2A, and FIG. It is a top view showing other examples.
In FIG. 1, a coil 1 is formed into a cylindrical shape by covering a spirally wound conductor with, for example, epoxy resin. A resin film layer 25 is provided on the inner periphery of the coil 1. The resin film layer 25 is formed by molding a film made of, for example, a polyimide resin into a cylindrical shape so as to match the entire inner peripheral surface of the coil 1, and is adhered to the inner peripheral surface of the coil 1 with an adhesive.
[0027]
The annular body 2 is disposed so as to be in close contact with one end of the coil 1 and the resin film layer 25, and is fixed by an adhesive.
As shown in FIG. 2B, a cylindrical portion 2A is provided on one surface of the annular body 2 so as to protrude in the axial direction. The cylindrical portion 2 </ b> A has an outer diameter to which the ends of the coil 1 and the resin film layer 25 can be fitted, and when the coil 1 and the resin film layer 25 are arranged on the annular body 2, the end of the coil 1. Has a role of fitting and holding. Further, the cylindrical portion 2A needs to be long enough not to collide with the inner yoke constituting the magnetic pole when the coil 1 reciprocates in the axial direction. The annular body 2 may be in close contact with the entire end of the coil 1 and the resin film layer 25 or may be in close contact with the entire end.
[0028]
The annular body 2 is formed of a metal or a synthetic resin, but is preferably made of a non-magnetic material because it is placed in a magnetic field. When the annular body 2 is made of a non-magnetic metal such as stainless steel or aluminum, a slit 2B in which one peripheral portion is completely cut as shown in FIG. As shown in the drawing, a structure having a slit 2C partially cut away is provided so that electrical continuity in the circumferential direction is interrupted and generation of eddy current is suppressed.
[0029]
A driving member 4 is provided on the outer surface of the annular body 2 via a cylindrical connecting member 3.
The annular body 2, the connecting member 3, and the driving member 4 are fixed to each other by a well-known method such as welding or fastening bolts and nuts.
The connecting member 3 has a cylindrical shape along the periphery of the annular body 2 and has through holes of an arbitrary size at several places around the periphery within a range that does not impair the mechanical strength in order to reduce the number of components. Is configured. Alternatively, the connecting member 3 may be configured so that a plurality of rod-like bodies are erected along the circumference of the annular body 2. As described above, it is preferable that the connecting member 3 is configured to be reduced in weight at the same time as the generation of the eddy current and to be easily dissipated.
[0030]
The driving member 4 is constituted by a board 4A having a center on an extension of the axis of the coil 1. At the center of the board 4A, a drive shaft 5 for transmitting the drive force in the axial direction of the coil to the outside is provided. One end of the drive shaft 5 is inserted through the board 4A of the drive member 4 and the annular body 2, and is fixed to the board 4A by welding.
The driving member 4 is formed of a metal or a synthetic resin, but is preferably made of a non-magnetic material such as stainless steel or aluminum because it is placed near a magnetic field.
The coil 1, the annular body 2, the connecting member 3, the driving member 4, and the driving shaft 5 are integrated to form a mover, which is incorporated between magnetic poles forming a magnetic field described below and driven by an electromagnetic force to perform a predetermined motion. do.
[0031]
FIG. 1 shows how the magnetic poles and the mover are mounted.
In FIG. 1, a cylindrical outer yoke 10 and an inner yoke 12 shorter than the outer yoke 10 are coaxially arranged and connected at one end by a connecting yoke 20 made of the same material. In the gap between the outer yoke 10 and the inner yoke 12, the magnet 11 and the coil 1 are disposed to face each other.
The magnet 11 is divided into a plurality of parts, and is arranged on the inner peripheral surface of the outer yoke 10 at appropriate intervals and is attracted by a strong magnetic force. The coil 1 is disposed in a gap 9 formed by a magnet 11 and an inner yoke 12 that form a magnetic field, and is movable without contacting each other.
[0032]
The mover having the above configuration is supported by the coil springs 19 and 22 disposed on both surfaces of the annular body 2 and the driving member 4 in a state of being always separated (floating) from the magnet 11 and the inner yoke 12. Positioning is also performed by appropriately balancing the clamping force between the two coil springs 19 and 22. It is preferable that the coil springs 19 and 22 have the same dimensions as each other, because the clamping pressure can be easily balanced. The two coil springs 19 and 22 apply a restoring force to the axial reciprocation of the coil 1 and resonate the coil 1 with a predetermined amplitude. One end of each of the coil springs 19 and 22 may be fixed to the annular body 2 and the driving member 4 or may simply be in contact with each other.
In the linear motor mover configured as described above, for example, the cylinder 30 of the compressor to be driven is fixed to the end plate 10A of the outer yoke by welding, and the drive shaft 5 is inserted into the cylinder 30 and attached as a piston. Used.
[0033]
【The invention's effect】
As described above, according to the present invention, since the resin film layer is provided on the inner periphery of the coil, even if the coil is not wound in an orderly manner, the coil contacts the magnetic pole forming the magnetic field in the movable region. The desired accuracy can be maintained without reciprocating motion. Further, the weight and size can be reduced with sufficient strength, and the generation of eddy current can be minimized.
[Brief description of the drawings]
FIG. 1 is a partially cutaway longitudinal sectional view showing one embodiment of a linear motor mover according to the present invention.
FIGS. 2A and 2B show a coil used in an embodiment of the present invention and an annular body fixed to one end of the coil, where FIG. 2A is a plan view and FIG. 2B is along AA in FIG. FIG. 6C is a longitudinal sectional view, and FIG. 7C is a plan view showing another example of the annular body.
FIG. 3 is a longitudinal sectional view showing a conventional mover for a linear motor.
FIG. 4 is a longitudinal sectional view specifically showing the portion of FIG. 2A.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 coil 2 annular body 3 connecting member 4 drive member 5 drive shaft 9 gap 10 outer yoke 11 magnet 12 inner yokes 19, 22 coil spring 25 resin film layer

Claims (7)

A coil formed by covering a spirally wound conductor with a resin and molding it into a cylindrical shape,
An annular body fixed to an end of the coil and having a common axis with the coil;
A driving member disposed in a direction away from the coil and at a predetermined distance from the annular body;
A connecting member that connects the annular body and the driving member;
A linear motor mover comprising: a drive shaft that movably supports the drive member so that the coil can reciprocate in a movable region.
A mover for a linear motor, wherein a resin film layer holding the coil is provided on an inner periphery of the coil. The mover for a linear motor according to claim 1,
A mover for a linear motor, wherein the resin film layer is made of a polyimide resin. The mover for a linear motor according to claim 1,
The movable body for a linear motor, wherein the annular body is formed of a metal and has a slit for cutting off electrical continuity in a circumferential direction. The mover for a linear motor according to claim 1,
The drive member includes a board having a center on an extension of the axis of the coil, and a drive shaft having one end fixed to the center of the board and transmitting an axial drive force of the coil to the outside. A mover for a linear motor, characterized in that: The mover for a linear motor according to claim 1,
The movable member for a linear motor, wherein the driving member is supported by an elastic member to apply a return force to the axial reciprocation of the coil. The mover for a linear motor according to claim 1,
The movable body for a linear motor, wherein the annular body includes an annular portion fixed to an end surface of the coil and a tubular portion extending in a direction toward an inner surface of an end of the coil. The mover for a linear motor according to claim 1,
The movable element for a linear motor, wherein the coil is composed of a first coil and a second coil which are arranged so as to have a common axis and to be separated from each other in the axial direction.

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