JPH11103568A - Movable magnet type linear actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a movable magnet type linear actuator which can efficiently generate magnetic forces to increase thrust, reduce the total weight of permanent magnets for contributing to cost reduction and the savings of resources and, furthermore, obtain high acceleration by the weight reduction of a whole movable unit. SOLUTION: Magnetic forces are generated in permanent magnets 4 by magnetic interactions between fluxes, which are generated by the permanent magnets 4 and by the application of a predetermined current to a drive coil 3 and pass through an inner yoke 1 and an outer yoke 2, of which a magnetic circuit is composed. A movable unit composed of the permanent magnets 4, a permanent magnet holding member 5 and spacers 6 are moved by a thrust given by the magnetic forces. From the effects of gaps provided between the permanent magnets 4, the magnetic forces are increased, and furthermore, the total weight of the permanent magnets 4 can be reduced by a weight corresponding to the volumes of the gaps, so that the contribution to cost reduction and savings of resources can be achieved, and further, since the weight of the whole movable unit is reduced, high acceleration can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to OA equipment, control equipment, electronic equipment, machine tools, semiconductor and liquid crystal manufacturing related equipment,
The present invention relates to a magnet movable linear actuator that generates a linear driving force in medical equipment and the like.

[0002]

2. Description of the Related Art FIG. 20 shows a conventional magnet movable linear actuator. FIG. 20 shows a sectional view of a conventional magnet movable linear actuator, wherein 1 is an inner yoke, 2 is an outer yoke, 3 is a drive coil wound around the outer yoke 2, and 4 is shown in FIG. The permanent magnet 5 and the permanent magnet 5 which are magnetized in the different directions are constituted by a permanent magnet holding member constituting a movable part together with the permanent magnet 4.

The operation of the movable magnet type linear actuator constructed as described above will be described below.

[0004] The magnetic effect of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to generate a magnetic force. A force is generated, and this magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4 and the permanent magnet holding member 5 moves.

[0005]

However, in the above-mentioned conventional structure, the use of expensive rare earth magnets is increased along with the improvement of thrust, so that the cost of the motor itself is increased, which is one of the factors that hinder industrialization. Had become.
Further, the magnetic force generated in the permanent magnet 4 appears only near the magnetic pole boundary surface in the axial direction of the permanent magnet 4, and the magnetic force in other portions is very small, so that the magnetic force can be efficiently obtained. Did not.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems. In the movable magnet type linear actuator, a magnetic force is efficiently generated to increase the thrust, and the weight of the permanent magnet can be reduced. An object of the present invention is to provide a movable magnet type linear actuator which can contribute to cost reduction and resource saving, and can obtain a high acceleration because the entire movable portion is lightweight.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a cylindrical inner yoke having magnetism and a magnetic concentrically arranged with a predetermined gap formed between the inner yoke and the inner yoke. An outer yoke having, a drive coil wound around at least one of the inner yoke and the outer yoke,
A permanent magnet holding member disposed substantially concentrically in an air gap between the inner yoke and the outer yoke; and a multi-pole magnetized magnet which is held by the permanent magnet holding member and whose magnetization direction is substantially radial and axial. In the movable movable linear actuator comprising a cylindrical permanent magnet formed as described above, a plurality of portions of the permanent magnet that are magnetized in the same direction are provided with a predetermined gap in the axial direction. Is a movable magnet type linear actuator.

As described above, by using the permanent magnet divided in the axial direction, the magnetic force can be efficiently generated to increase the thrust, and the weight of the permanent magnet can be reduced, which contributes to cost reduction and resource saving. It is possible to achieve high acceleration because the entire movable part is lighter.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to solve the above-mentioned problems, the present invention is directed to a cylindrical inner yoke having magnetism, and a magnet having a predetermined gap formed with the inner yoke and arranged substantially concentrically. An outer yoke, a drive coil wound around at least one of the inner yoke and the outer yoke, and a permanent magnet holding member disposed substantially concentrically in an air gap between the inner yoke and the outer yoke, In the movable magnet linear actuator, which is a cylindrical permanent magnet that is held by the permanent magnet holding member and has a magnetization direction substantially radially and axially multipolarly magnetized, the permanent magnet is attached in the same direction. A movable magnet type linear actuator, wherein a plurality of magnetized portions are arranged with a predetermined gap formed in the axial direction. As described above, by using the permanent magnet divided in the axial direction, the magnetic force can be efficiently generated to increase the thrust, and the permanent magnet can be lightened, which contributes to cost reduction and resource saving. High acceleration can be obtained because the entire movable portion is light in weight.

Further, the dimension Lg of the gap of the permanent magnet satisfies 0 <Lg <Lc with respect to the axial dimension Lc of the drive coil.

Further, the permanent magnet is divided in a substantially circumferential direction. Further, at least one of the inner yoke and the outer yoke is divided in a substantially circumferential direction.

Further, at least one of the inner yoke and the outer yoke is made of a thin plate, and the laminating direction is substantially the circumferential direction.

Also, at least one of the inner yoke and the outer yoke is made of a thin plate, and the laminating direction is divided in the axial direction and substantially in the circumferential direction.

The thin plate forming at least one of the inner yoke and the outer yoke is a directional magnetic plate.

In addition, the permanent magnet divided in the axial direction is positioned by a spacer made of a non-magnetic and high-resistance member.

Further, the permanent magnet holding member is made of a non-magnetic and high-resistance member. Further, the permanent magnet holding member has a plurality of slits in the axial direction.

At least one end of the permanent magnet holding member has an L-shape.

Further, the permanent magnet holding member and the spacer for forming a gap between the permanent magnets are integrated.

Further, the movable magnet type linear actuator of the present invention is used for a compressor.

[0020]

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

(Embodiment 1) FIG. 1 is a sectional view of a movable magnet type linear actuator according to a first embodiment of the present invention. In FIG. 1, 1 is an inner yoke, 2 is an outer yoke, and 3 is an outer yoke. A drive coil wound around the yoke 2 is a permanent magnet holding member, 5 is a spacer, and 4 is a permanent magnet magnetized in the direction shown in FIG.

The operation of the movable magnet type linear actuator configured as described above will be described below.

The magnetic effect of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to be magnetic. A force is generated, and the magnetic force acts as a thrust to move the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6. Here, the permanent magnet 4 holds a predetermined gap by the spacer 6, and the relationship between the gap size Lg and the magnetic force F acting on the permanent magnet 4 has a distribution as shown in FIG. Assuming that the axial length of the drive coil 3 is Lc and the magnetic force when the gap size Lg is zero is F0, the gap size Lg is increased from zero and the magnetic force F increases as shown in FIG.
, The magnetic force F becomes the maximum value, and when the gap size Lg is further increased, the magnetic force F decreases, and almost becomes F = F0 when Lg = Lc. That is, if the gap size Lg satisfies 0 <Lg <Lc, the magnetic force increases. Further, since the permanent magnet corresponding to the volume of the space is light, it is possible to contribute to cost reduction and resource saving. Further, since the entire movable part is light, high acceleration can be obtained.

In the above description, the drive coil 3 is wound around the outer yoke 2, but the drive coil 3 may be wound around the inner yoke 1.

(Embodiment 2) FIG. 3 is a sectional view of a movable magnet type linear actuator according to a second embodiment of the present invention. In FIG. 3, reference numeral 1 denotes an inner yoke, 2 denotes an outer yoke, and 3 denotes an outer yoke. A drive coil wound around the yoke 2, a permanent magnet holding member 5, a spacer 6, and a permanent magnet 4 magnetized in the direction shown in FIG. The difference from FIG. 1 is that the permanent magnet 4 is divided substantially in the circumferential direction as shown in FIG.

The operation of the movable magnet type linear actuator configured as described above will be described below.

The magnetic action of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to have a magnetic effect. A force is generated, and the magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6 moves. At this time, the magnetized portion of the permanent magnet 4 in the same direction is divided in the axial direction to form a predetermined gap, thereby increasing the thrust and reducing the volume of the volume-integrated permanent magnet 4 so that the cost can be reduced. This can contribute to resource saving, and furthermore, the entire movable part is reduced in weight, so that a high acceleration can be obtained. Further, since the permanent magnet 4 is divided substantially in the circumferential direction, it can be easily magnetized and assembled.

In the above description, the drive coil 3 is wound around the outer yoke 2, but it is also possible to wind the drive coil 3 around the inner yoke 1.

(Embodiment 3) FIG. 5 is a sectional view of a movable magnet type linear actuator according to a third embodiment of the present invention. In FIG. 5, reference numeral 1 denotes an inner yoke, 2 denotes an outer yoke, and 3 denotes an outer yoke. A drive coil wound around the yoke 2, a permanent magnet holding member 5, a spacer 6, and a permanent magnet 4 magnetized in the direction shown in FIG. The difference from FIG. 1 is that the inner yoke 1 and the outer yoke 2 are divided substantially in the circumferential direction as shown in FIG. FIG. 6 shows only the inner yoke 1.

The operation of the movable magnet type linear actuator configured as described above will be described below.

The magnetic action of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to have a magnetic force. A force is generated, and the magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6 moves. At this time, the magnetized portion of the permanent magnet 4 in the same direction is divided in the axial direction to form a predetermined gap, thereby increasing the thrust and reducing the volume of the volume-integrated permanent magnet 4 so that the cost can be reduced. This can contribute to resource saving, and furthermore, the entire movable part is reduced in weight, so that a high acceleration can be obtained. Further, since the inner yoke 1 and the outer yoke 2 are divided in a substantially circumferential direction, eddy currents generated therein and heat generated by the eddy currents can be suppressed, and assembly can be easily performed.

In the above description, the drive coil 3 is wound around the outer yoke 2, but the drive coil 3 may be wound around the inner yoke 1.

(Embodiment 4) FIG. 7 is a sectional view of a movable magnet type linear actuator according to a fourth embodiment of the present invention. In FIG. 7, 1 is an inner yoke, 2 is an outer yoke, and 3 is an outer yoke. A drive coil wound around the yoke 2 is a permanent magnet holding member, 5 is a spacer, and 4 is a permanent magnet magnetized in the direction shown in FIG. The difference from FIG. 1 is that the inner yoke 1 and the outer yoke 2 are formed of thin plates, and the laminating direction is substantially the circumferential direction as shown in FIG.
FIG. 8 shows only the inner yoke 1.

The operation of the movable magnet type linear actuator configured as described above will be described below.

The magnetic action of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to have a magnetic effect. A force is generated, and the magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6 moves.
At this time, the magnetized portion of the permanent magnet 4 in the same direction is divided in the axial direction to form a predetermined gap, thereby increasing the thrust and reducing the volume of the volume-integrated permanent magnet 4 so that the cost can be reduced. This can contribute to resource saving, and furthermore, the entire movable part is reduced in weight, so that a high acceleration can be obtained. Also, by laminating the inner yoke 1 and the outer yoke 2 substantially in the circumferential direction,
The eddy current generated thereby and the heat generated by the eddy current can be suppressed.

In the above description, the drive coil 3 is wound around the outer yoke 2, but it is also possible to wind the drive coil 3 around the inner yoke 1. Further, the inner yoke 1 and the outer yoke 2 are stacked in a substantially circumferential direction as shown in FIG. 8, but the present invention can also be carried out by stacking as shown in FIG.

(Embodiment 5) FIG. 10 is a sectional view of a movable magnet type linear actuator according to a fifth embodiment of the present invention. In FIG. 10, reference numeral 1 denotes an inner yoke, 2 denotes an outer yoke, and 3 denotes an outer yoke. Drive coil wound around the yoke 2, 5
Is a permanent magnet holding member, 6 is a spacer, and 4 is a permanent magnet magnetized in the direction shown in FIG. The difference from FIG. 1 is that the inner yoke 1 and the outer yoke 2 are divided substantially in the circumferential direction as shown in FIG. 11 and are laminated in the axial direction. FIG. 11 shows only the inner yoke 1.

The operation of the movable magnet type linear actuator configured as described above will be described below.

The magnetic effect of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to be magnetically magnetized. A force is generated, and the magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6 moves. At this time, the portion magnetized in the same direction of the permanent magnet 4 is divided in the axial direction to form a predetermined gap, thereby increasing the thrust and reducing the volume of the volume-integrated permanent magnet 4 to reduce the cost. It is possible to contribute to cost reduction and resource saving, and furthermore, it is possible to obtain high acceleration since the entire movable part is lightened. Further, since the inner yoke 1 and the outer yoke 2 are divided substantially in the circumferential direction and stacked in the axial direction, eddy currents generated therein and heat generated by the eddy currents can be suppressed, and assembly is facilitated. be able to.

In the above description, the drive coil 3 is wound around the outer yoke 2, but it is also possible to wind the drive coil 3 around the inner yoke 1.

(Embodiment 6) FIG. 12 is a sectional view of a movable magnet type linear actuator according to a sixth embodiment of the present invention. In FIG. 12, 1 is an inner yoke, 2 is an outer yoke, and 3 is an outer yoke. Drive coil wound around the yoke 2, 5
Is a permanent magnet holding member, 6 is a spacer, and 4 is a permanent magnet magnetized in the direction shown in FIG. The difference from FIG. 1 is that the thin plates forming the inner yoke 1 and the outer yoke 2 are magnetic plates having directivity.

The operation of the movable magnet type linear actuator configured as described above will be described below.

The magnetic action of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to have a magnetic force. A force is generated, and the magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6 moves. At this time, the portion magnetized in the same direction of the permanent magnet 4 is divided in the axial direction to form a predetermined gap, thereby increasing the thrust and reducing the volume of the volume-integrated permanent magnet 4 to reduce the cost. It is possible to contribute to cost reduction and resource saving, and furthermore, it is possible to obtain high acceleration since the entire movable part is lightened. Further, since the inner yoke 1 and the outer yoke 2 are made of directional magnetic plates, the magnetic resistance in the yoke can be reduced, and the magnetic force can be increased.

In the above description, the drive coil 3 is wound around the outer yoke 2, but it is also possible to wind the drive coil 3 around the inner yoke 1.

(Embodiment 7) FIG. 13 is a sectional view of a movable magnet type linear actuator according to a seventh embodiment of the present invention. In FIG. 13, reference numeral 1 denotes an inner yoke, 2 denotes an outer yoke, and 3 denotes an outer yoke. Drive coil wound around the yoke 2, 5
Is a permanent magnet holding member, 6 is a spacer, and 4 is a permanent magnet magnetized in the direction shown in FIG. The difference from FIG. 1 is that the spacer 6 is a non-magnetic and high-resistance member.

The operation of the movable magnet type linear actuator configured as described above will be described below.

The magnetic effect of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to have a magnetic force. A force is generated, and the magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6 moves. At this time, the portion magnetized in the same direction of the permanent magnet 4 is divided in the axial direction to form a predetermined gap, thereby increasing the thrust and reducing the volume of the volume-integrated permanent magnet 4 to reduce the cost. It is possible to contribute to cost reduction and resource saving, and furthermore, it is possible to obtain high acceleration since the entire movable part is lightened. In addition, since the spacer 6 is made of a non-magnetic and high-resistance member, the eddy current generated therein and the heat generated by the eddy current can be suppressed, and further the demagnetization of the permanent magnet 4 due to the heat generated by the spacer 6 can be suppressed. .

In the above description, the drive coil 3 is wound around the outer yoke 2, but it is also possible to wind the drive coil 3 around the inner yoke 1.

(Embodiment 8) FIG. 14 is a sectional view of a movable magnet type linear actuator according to an eighth embodiment of the present invention. In FIG. 14, reference numeral 1 denotes an inner yoke, 2 denotes an outer yoke, and 3 denotes an outer yoke. Drive coil wound around the yoke 2, 5
Is a permanent magnet holding member, 6 is a spacer, and 4 is a permanent magnet magnetized in the direction shown in FIG. The difference from FIG. 1 is that the permanent magnet holding member 5 is a non-magnetic and high-resistance member.

The operation of the movable magnet type linear actuator configured as described above will be described below.

The magnetic effect of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to have a magnetic effect. A force is generated, and the magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6 moves. At this time, the portion magnetized in the same direction of the permanent magnet 4 is divided in the axial direction to form a predetermined gap, thereby increasing the thrust and reducing the volume of the volume-integrated permanent magnet 4 to reduce the cost. It is possible to contribute to cost reduction and resource saving, and furthermore, it is possible to obtain high acceleration since the entire movable part is lightened. In addition, since the permanent magnet holding member 5 is made of a non-magnetic and high-resistance member, eddy current generated therein and heat generated by the eddy current can be suppressed, and further, demagnetization of the permanent magnet 4 due to heat generation of the permanent magnet holding member 5. Can be suppressed.

In the above description, the drive coil 3 is wound around the outer yoke 2, but it is also possible to wind the drive coil 3 around the inner yoke 1.

(Embodiment 9) FIG. 15 is a sectional view of a movable magnet type linear actuator according to a ninth embodiment of the present invention. In FIG. 15, reference numeral 1 denotes an inner yoke, 2 denotes an outer yoke, and 3 denotes an outer yoke. Drive coil wound around the yoke 2, 5
Is a permanent magnet holding member, 6 is a spacer, and 4 is a permanent magnet magnetized in the direction shown in FIG. The difference from FIG. 1 is that the permanent magnet holding member 5 is provided with a slit as shown in FIG.

The operation of the movable magnet type linear actuator configured as described above will be described below.

The magnetic action of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to have a magnetic effect. A force is generated, and the magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6 moves. At this time, the portion magnetized in the same direction of the permanent magnet 4 is divided in the axial direction to form a predetermined gap, thereby increasing the thrust and reducing the volume of the volume-integrated permanent magnet 4 to reduce the cost. It is possible to contribute to cost reduction and resource saving, and furthermore, it is possible to obtain high acceleration since the entire movable part is lightened. Further, by providing the slit in the permanent magnet holding member 5, it is possible to suppress the eddy current generated therein and the heat generated by the eddy current,
Further, demagnetization of the permanent magnet 4 due to heat generation of the permanent magnet holding member 5 can be suppressed.

In the above description, the drive coil 3 is wound around the outer yoke 2, but it is also possible to wind the drive coil 3 around the inner yoke 1.

(Embodiment 10) FIG. 17 is a sectional view of a movable magnet type linear actuator according to a tenth embodiment of the present invention. In FIG. 17, 1 is an inner yoke, 2 is an outer yoke, and 3 is an outer yoke. The drive coil wound around the yoke 2, 5 is a permanent magnet holding member, 6 is a spacer, 4 is FIG.
It is a permanent magnet magnetized in the direction indicated therein. The difference from FIG. 1 is that the end of the permanent magnet holding member 5 is L-shaped as shown in FIG.

The operation of the movable magnet type linear actuator configured as described above will be described below.

The magnetic action of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to have a magnetic effect. A force is generated, and the magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6 moves. At this time, the portion magnetized in the same direction of the permanent magnet 4 is divided in the axial direction to form a predetermined gap, thereby increasing the thrust and reducing the volume of the volume-integrated permanent magnet 4 to reduce the cost. It is possible to contribute to cost reduction and resource saving, and furthermore, it is possible to obtain high acceleration since the entire movable part is lightened. In addition, since the end of the permanent magnet holding member 5 is L-shaped, the positioning of the permanent magnet 4 can be facilitated.

In the above description, the drive coil 3 is wound around the outer yoke 2, but it is also possible to wind the drive coil 3 around the inner yoke 1.

(Embodiment 11) FIG. 19 is a sectional view of a movable magnet type linear actuator according to an eleventh embodiment of the present invention. In FIG. 17, reference numeral 1 denotes an inner yoke, 2 denotes an outer yoke, and 3 denotes an outer yoke. The drive coil wound around the yoke 2, 5 is a permanent magnet holding member, 6 is a spacer, 4 is FIG.
It is a permanent magnet magnetized in the direction indicated therein. 3 in that the permanent magnet holding member 5 and the spacer 6 are integrated.

The operation of the thus configured magnetic movable linear actuator will be described below.

The magnetic action of the magnetic flux generated by the permanent magnet 4 flowing through the inner yoke 1 and the outer yoke 2 constituting the magnetic circuit and the magnetic flux generated by applying a predetermined current to the drive coil 3 causes the permanent magnet 4 to have a magnetic effect. A force is generated, and the magnetic force becomes a thrust, so that the movable portion including the permanent magnet 4, the permanent magnet holding member 5, and the spacer 6 moves. At this time, the portion magnetized in the same direction is divided in the axial direction to form a predetermined gap, thereby increasing the thrust and reducing the volume of the volume-integrated permanent magnet 4 to reduce the cost. It is possible to contribute to cost reduction and resource saving, and furthermore, it is possible to obtain high acceleration since the entire movable part is lightened. In addition, since the permanent magnet holding member 5 and the spacer 6 are integrated,
The number of parts can be reduced, and the positioning of the permanent magnet 4 can be further facilitated.

In the above description, the drive coil 3 is wound around the outer yoke 2, but it is also possible to wind the drive coil 3 around the inner yoke 1.

[0065]

As is apparent from the above embodiment, according to the first and second aspects of the present invention, the cylindrical magnet whose magnetization direction is substantially radial and axially multipolar magnetized. Among the permanent magnets, a plurality of portions magnetized in the same direction are provided so as to form a predetermined gap in the axial direction, and the dimension Lg of the gap is 0% with respect to the axial dimension Lc of the drive coil. <L
By satisfying g <Lc, the thrust is increased, and the volume-integrated permanent magnet in the air gap becomes lighter, which contributes to cost reduction and resource saving. Further, since the entire movable part is lightened, high acceleration is achieved. Obtainable.

According to the third aspect of the present invention, since the cylindrical permanent magnet is divided in the substantially circumferential direction, the above-described effects can be obtained, and the magnetizing and permanent magnet of the permanent magnet can be obtained. Easy to assemble.

According to the fourth aspect of the invention, at least one of the yokes is divided in a substantially circumferential direction, so that the above-described effects can be obtained.
Eddy current generated in the yoke and heat generated by the eddy current can be suppressed, and assembly can be further facilitated.

According to the fifth aspect of the present invention, at least one of the yokes is made of a thin plate, and the laminating direction is substantially the circumferential direction. The generated eddy current and heat generated by the eddy current can be suppressed.

According to the invention described in claim 6, at least one of the yokes is made of a thin plate, and the laminating direction is divided in the axial direction and substantially in the circumferential direction. The effect can be obtained, the eddy current generated in the yoke and the heat generated by the eddy current can be suppressed, and the assembly can be further facilitated.

According to the seventh aspect of the present invention, at least one of the yokes is made of a thin plate, and the thin plate has directionality, so that the above-described effects can be obtained, and the magnetic resistance of the yoke can be improved. , The thrust is further improved, and a high acceleration can be obtained.

According to the eighth aspect of the present invention, the permanent magnet is positioned by the spacer made of a non-magnetic and high-resistance member, so that the effects described above can be obtained, and the eddy current generated in the spacer can be reduced. Heat generation due to eddy current can be suppressed, demagnetization of the permanent magnet due to heat generation of the spacer can be suppressed, and positioning of the permanent magnet can be facilitated.

According to the ninth aspect of the present invention, the effect as described above can be obtained by making the permanent magnet holding member a non-magnetic and high resistance member, and the eddy current generated in the permanent magnet holding member can be obtained. Thus, heat generation due to eddy current can be suppressed, and demagnetization of the permanent magnet due to heat generation can be suppressed.

According to the tenth aspect of the present invention,
Since the permanent magnet holding member has a plurality of slits in the axial direction, the above-described effects can be obtained, and eddy current generated in the permanent magnet holding member and heat generation due to the eddy current can be suppressed. Demagnetization of the permanent magnet can be suppressed.

According to the eleventh aspect of the present invention,
Since at least one end of the permanent magnet holding member has an L-shape, the above-described effects can be obtained, and the positioning of the permanent magnet can be easily performed.

According to the twelfth aspect of the present invention,
By integrating the permanent magnet holding member and the spacer, the effects described above can be obtained, and the number of components can be reduced and the positioning of the permanent magnet can be easily performed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a movable magnet type linear actuator according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a gap size Lg of a permanent magnet and a magnetic force F acting on the permanent magnet.

FIG. 3 is a sectional view showing a movable magnet type linear actuator according to a second embodiment of the present invention;

FIG. 4 is a bird's-eye view of a permanent magnet according to a second embodiment of the present invention.

FIG. 5 is a sectional view showing a movable magnet type linear actuator according to a third embodiment of the present invention.

FIG. 6 is a bird's-eye view of an inner yoke according to a third embodiment of the present invention.

FIG. 7 is a sectional view showing a movable magnet type linear actuator according to a fourth embodiment of the present invention.

FIG. 8 is a top view of an inner yoke according to a fourth embodiment of the present invention.

FIG. 9 is a top view of an inner yoke according to a fourth embodiment of the present invention.

FIG. 10 is a sectional view showing a movable magnet type linear actuator according to a fifth embodiment of the present invention.

FIG. 11 is a bird's-eye view of an inner yoke according to a fifth embodiment of the present invention.

FIG. 12 is a sectional view showing a movable magnet type linear actuator according to a sixth embodiment of the present invention.

FIG. 13 is a sectional view showing a movable magnet type linear actuator according to a seventh embodiment of the present invention.

FIG. 14 is a sectional view showing a movable magnet type linear actuator according to an eighth embodiment of the present invention.

FIG. 15 is a sectional view showing a movable magnet type linear actuator according to a ninth embodiment of the present invention.

FIG. 16 is a bird's-eye view of a permanent magnet holding member according to a ninth embodiment of the present invention.

FIG. 17 is a sectional view showing a movable magnet type linear actuator according to a tenth embodiment of the present invention.

FIG. 18 is a bird's-eye view of a permanent magnet holding member according to a tenth embodiment of the present invention.

FIG. 19 is a sectional view showing a movable magnet type linear actuator according to an eleventh embodiment of the present invention.

FIG. 20 is a sectional view showing a conventional magnet movable linear actuator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner yoke 2 Outer yoke 3 Drive coil 4 Permanent magnet 5 Permanent magnet holding member 6 Spacer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Takinami 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (13)

[Claims] 1. A cylindrical inner yoke having magnetism, an outer yoke having magnetism formed in a substantially concentric manner by forming a predetermined gap with the inner yoke, and at least one of the inner yoke and the outer yoke. A drive coil wound around one of them,
A permanent magnet holding member disposed substantially concentrically in an air gap between the inner yoke and the outer yoke; and a multi-pole magnetized magnet which is held by the permanent magnet holding member and whose magnetization direction is substantially radial and axial. In the magnet movable linear actuator made of a cylindrical permanent magnet formed as described above, a plurality of portions of the permanent magnet that are magnetized in the same direction are provided with a predetermined gap in the axial direction. A movable magnet type linear actuator. 2. The movable magnet type linear actuator according to claim 1, wherein the dimension Lg of the gap of the permanent magnet satisfies 0 <Lg <Lc with respect to the axial dimension Lc of the drive coil. 3. The linear actuator according to claim 1, wherein the cylindrical permanent magnet is divided in a substantially circumferential direction. 4. The magnet movable linear actuator according to claim 1, wherein at least one of the inner yoke and the outer yoke is divided in a substantially circumferential direction. 5. The movable magnet type linear actuator according to claim 1, wherein at least one of the inner yoke and the outer yoke is formed of a thin plate, and a laminating direction thereof is substantially a circumferential direction. 6. The apparatus according to claim 1, wherein at least one of the inner yoke and the outer yoke is formed of a thin plate, and the laminating direction is divided in the axial direction and substantially in the circumferential direction. Magnet movable linear actuator. 7. A thin plate constituting at least one of the inner yoke and the outer yoke is a directional magnetic plate.
The movable magnet type linear actuator as described in the above. 8. The movable magnet linear actuator according to claim 1, wherein the permanent magnet divided in the axial direction is positioned by a spacer made of a non-magnetic and high-resistance member. 9. A movable magnet type linear actuator according to claim 1, wherein the permanent magnet holding member is made of a non-magnetic and high-resistance member. 10. The magnet movable linear actuator according to claim 1, wherein the permanent magnet holding member has a plurality of slits in an axial direction. 11. The movable magnet linear actuator according to claim 1, wherein at least one end of the permanent magnet holding member has an L-shape. 12. The movable magnet linear actuator according to claim 3, wherein the permanent magnet holding member and a spacer for forming a gap between the permanent magnets are integrated. 13. The compressor according to claim 1, wherein a movable magnet type linear actuator is used.