JP2002034224A - Magnet-movable linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To narrow air gaps 14 for enhancing the thrust and efficiency of a motor by holding permanent magnets 22 on a magnet-holding body 24 by magnetic attractive force produced between the permanent magnets and a laminated stator core 18. SOLUTION: The magnet-movable linear motor 10 is formed, by movably placing the permanent magnets 22 is specified air gaps 14 in the laminated stator core 18 with excitation coils 20 wound thereon. The permanent magnets 22, having for example, substantially trapezoidal cross sections, are inserted into mounting holes formed in the magnet holding body 24 made of a nonmagnetic material and placed off the center of the air gaps. The permanent magnets 22 are held on the magnet-holding body 24 by magnetic attractive force produced between the laminated stator core 18 and the permanent magnets 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable magnet type linear motor, and more particularly to a movable magnet type linear motor in which, for example, a permanent magnet as a mover is held on a non-magnetic magnet holding member by magnetic attraction.

[0002]

2. Description of the Related Art A conventional magnet movable linear motor 1 (see Japanese Patent No. 2992265) is disclosed in, for example, FIGS.
As shown in the figure, the laminated stator core 2 has an inner yoke 3a on which electromagnetic steel sheets are laminated, an inner yoke 3a and a predetermined gap 4
The outer yoke 3b also includes an outer yoke 3b in which electromagnetic steel sheets are stacked, and the coil 5 is mounted inside the outer yoke 3b.

[0003] A permanent magnet 6 as a mover movably disposed in an air gap (air gap) 4 of the laminated stator core 2 is provided on a peripheral side surface of a hollow cylindrical magnet holder 7 having one open side. The magnets are fitted into magnet insertion holes 8 formed in a trapezoidal shape at intervals, and then a cylindrical magnet fixing ring 9 is attached to the hollow cylindrical magnet body 7 to fix and hold the permanent magnet 6. That is, each magnet insertion hole 8 formed in a trapezoidal shape
The upper side is formed longer than the lower side, and the permanent magnet 6 fitted in the magnet insertion hole 8 is formed in a substantially trapezoidal cross section.

[0004]

As a result, the air gap 4 in which the permanent magnet 6 is movably arranged, that is, the air gap is widened, and the thrust of the motor is reduced. When the metal cylindrical magnet fixing ring 9 is used, there is a problem that weight and loss (eddy current loss) increase, and it becomes difficult to improve the performance of the motor.

[0005] Therefore, a main object of the present invention is to provide a movable magnet type linear motor capable of securely holding a permanent magnet serving as a mover and improving the thrust and motor efficiency of the motor with a simple structure. .

[0006]

SUMMARY OF THE INVENTION The present invention provides a laminated stator core having a predetermined gap between an outer yoke and an inner yoke, an exciting coil mounted on the laminated stator core, and a movable member provided in the predetermined gap. In the movable magnet linear motor having the arranged permanent magnets, the permanent magnets are formed such that the outer side is longer than the inner side in the cross-sectional shape and are inserted into mounting holes provided in the magnet holding member located in the gap, and the laminated stator core is provided. And a magnet-moving linear motor characterized in that the magnet-moving linear motor is held by a magnet holding member by a magnetic attraction force generated between the two.

Another invention provides a laminated stator core having a predetermined gap between an outer yoke and an inner yoke, an exciting coil mounted on the laminated stator core, and movably disposed in the predetermined gap. In the magnet movable linear motor having the permanent magnet, the permanent magnet has a two-part configuration in which the outer side is longer than the inner side in the cross-sectional shape, and the two-part permanent part is formed in a mounting hole provided in the magnet holding member located in a predetermined gap. A magnet movable linear motor characterized in that magnets are opposed to each other with opposite polarities so that the magnet holding member is sandwiched by mutual magnetic attraction.

[0008]

Since the permanent magnet movably disposed in the gap of the laminated stator core is held by the magnet holding member by the magnetic attraction generated between the permanent magnet and the core, no separate fixing means is required.

[0009]

According to the present invention, the permanent magnet disposed in the gap of the laminated stator core can be easily held on the magnet holding member by magnetic attraction. As a result, the air gap can be reduced, the thrust of the motor increases, and there is no eddy current loss, so that the motor efficiency improves.

The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the accompanying drawings.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a movable magnet type linear motor 10 according to the present invention shown in FIG. 1 is an outer yoke provided with a predetermined gap (air gap) 14 between the inner yoke 12 and the inner yoke 12. 16, an excitation coil 20 mounted on the laminated stator core 18, and a predetermined gap 14 of the laminated stator core 18.
And a permanent magnet 22 as a mover that is movably disposed on the movable member.

The laminated stator core 18 is formed, for example, by laminating electromagnetic steel sheets punched into a predetermined shape from an electromagnetic steel strip.
The stator is configured by being arranged in a ring shape.

The exciting coil 20 is formed in a ring shape, and is mounted inside the inner yoke 12 of each laminated stator core 18.

The permanent magnet 22 as a mover is made of a non-magnetic material and has a hollow cylindrical magnet holder 24 which is open on one side.
And the disk-shaped central portion 2 of the magnet holder 24
4a is fixed to the shaft 26 arranged on the central axis CC.

That is, as shown in FIG. 3, each permanent magnet 22 has a substantially trapezoidal cross section or a convex shape in cross section, while the permanent magnet 22
Are formed at intervals of 45 °. Then, the permanent magnets 22 are inserted into the respective mounting holes 28, and the permanent magnets 22 are magnetized by magnetic attraction generated between the inner yoke 12 and the outer yoke 16 constituting the laminated stator core 18 and the respective permanent magnets 22. It is fixedly held on a holding body 24.

In the embodiment shown in FIG. 1, the permanent magnet 22 is disposed at the center of the predetermined gap (air gap) 14, and is held by the magnet holder 24 by the difference between the upper and lower magnetic attractive forces.

In another embodiment shown in FIG.
The permanent magnet 22 is disposed closer to the inner yoke 12 than the center of the predetermined gap (air gap) 14, and is permanently attached to the magnet holder 24 by magnetic attraction generated between the inner yoke 12 and the permanent magnet 22. The magnet 22 is held.

FIGS. 4 and 5 show still another embodiment in which the permanent magnet 22 is held by the hollow cylindrical magnet holder 24. FIG.

In the embodiment shown in FIG.
Are divided into two parts, a permanent magnet piece 22a and a permanent magnet piece 22.
b and these permanent magnet pieces 22a and 22
b has a substantially trapezoidal cross section. And
For example, eight mounting holes 30 are formed in the hollow cylindrical magnet holder 24, and when a pair of permanent magnet pieces 22 a and 22 b are oppositely arranged from both inside and outside of each mounting hole 30 with opposite polarities, mutual magnetic attraction is achieved. The two permanent magnet pieces 22a and 22b are held in the mounting holes 30 by the force while holding the magnet holder 24 therebetween.

In the embodiment of FIG. 5, the permanent magnet 22 is divided into two parts, and is divided into a permanent magnet piece 22a and a permanent magnet piece 22b. Each of the permanent magnet pieces 22a and 22b has a substantially convex cross section. Is formed. Except for this point, the same parts as those in the embodiment of FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted.

In the embodiment of FIGS. 4 and 5,
Although not shown, eight stator cores are arranged annularly at intervals of 45 ° to form a stator.

The magnetic attraction force acting on each of the permanent magnets 22 is orthogonal to the direction in which these magnets reciprocate in the predetermined gap 14 formed in the laminated stator core 18. Does not fall out of the mounting hole 30 of the magnet holder 24 due to the reciprocating motion.

The cross-sectional shape of the permanent magnet 22 is not limited to the above-described embodiment.
Outer side (upper side) than inner side (lower side) in relation to 0
Should be formed long.

Next, the operation will be briefly described.

In FIG. 1 or FIG. 2, when an alternating current is applied to the exciting coil 20 mounted on the laminated stator core 18, a magnetic flux generated in the magnetic circuit by the current in accordance with the direction of the current causes a gap (air gap). 14 acts on the permanent magnets 22 arranged on the side of the magnet 14 and the permanent magnets 22
Moves and is displaced rightward or leftward. That is,
The permanent magnet 22 reciprocates in synchronization with the frequency of the alternating current.

Accordingly, the movement of the permanent magnet 22 is transmitted to the shaft 26 located on the center axis CC through the hollow cylindrical magnet holder 24, and the shaft 26 reciprocates as an output shaft. If a piston that moves in a cylinder of the compressor is connected to the shaft 26, a linear compressor that compresses refrigerant or the like is realized.

As described above, in the present invention, the permanent magnets, which are arranged in the gaps of the laminated stator cores and serve as movers, are formed in a substantially trapezoidal or convex shape in cross section and provided on the hollow cylindrical magnet holder. Since it is inserted into the mounting hole and held by the magnet holder, for example, by a magnetic attraction force generated between the inner yoke, the air gap, that is, an air gap can be reduced and additional means for fixing is required. As a result, the thrust and efficiency of the motor are improved.

The permanent magnet is divided into two parts having a substantially trapezoidal shape or a convex shape in cross section, and the permanent magnets having the two-part structure are arranged opposite to each other with opposite polarities in mounting holes provided in the magnet holder, so that mutual magnets can be formed. Since the magnet holder is sandwiched and held by the attractive force, the same effect as in the previous embodiment can be obtained in this case as well.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing a schematic configuration of a movable magnet type linear motor according to an embodiment of the present invention;

FIG. 2 is an illustrative view of another embodiment corresponding to FIG. 1;

FIG. 3 is an illustrative view showing a partial cross section showing a holding state of a permanent magnet in FIGS. 1 and 2;

FIG. 4 is an illustrative view of another embodiment corresponding to FIG. 3;

FIG. 5 is an illustrative view of still another embodiment corresponding to FIG. 4;

FIG. 6 is an illustrative view showing a cross section of a main part of a movable magnet type linear motor showing a conventional example.

FIG. 7 is a sectional view of a main part including a hollow cylindrical magnet holder in FIG. 6;

[Description of Signs] 10 ... Magnet movable linear motor 12 ... Inner yoke 14 ... Void (air gap) 16 ... Outer yoke 18 ... Laminated stator core 20 ... Exciting coil 22 ... Permanent magnet 24 ... Hollow cylindrical magnet holder 26 ... Shafts 28, 30 ... Mounting holes

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsuji Ueda 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. F-term (reference) 5H633 BB08 GG02 GG04 GG09 HH03 HH22 JA10

Claims (3)

[Claims] 1. A laminated stator core having a predetermined gap between an outer yoke and an inner yoke, an exciting coil mounted on the laminated stator core, and a permanent magnet movably disposed in the predetermined gap. In the magnet movable linear motor, the permanent magnet has an outer side longer than an inner side in a cross-sectional shape, and is inserted into a mounting hole provided in a magnet holding member located in the predetermined gap, and between the permanent magnet and the laminated stator core. A magnet-movable linear motor, wherein said magnet-moving linear motor is held by said magnet holding member by a magnetic attractive force generated in said magnet-holding member. 2. The magnet movable linear motor according to claim 1, wherein said permanent magnet is held by said magnet holding member by magnetic attraction generated between said inner yoke and said outer yoke. 3. A laminated stator core having a predetermined gap between an outer yoke and an inner yoke, an exciting coil mounted on the laminated stator core, and a permanent magnet movably disposed in the predetermined gap. In the magnet movable linear motor, the permanent magnet has a two-part structure in which an outer side is longer than an inner side in a sectional shape, and the permanent magnet having the two-part structure is provided in a mounting hole provided in a magnet holding member located in the predetermined gap. Characterized in that the magnet holding members are sandwiched by mutual magnetic attraction by opposing the magnets in opposite polarities.