JP2002034226A - Magnet-movable linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the thrust of a motor and reduce eddy-current loss for the enhancement of motor efficiency by reducing air gaps. SOLUTION: The magnet-movable linear motor 10 is formed, by movable placing permanent magnets 22 at prescribed air gaps 14 in a laminated stator core 18, with excitation coils 20 wound thereon. Sides 30a of a pair of nonmagnetic metal plates 30 and 30 having substantially L-shaped cross sections are bonded to each of the rectangular parallelepiped permanent magnets 22, and the permanent magnets 22 are respectively fit into a plurality of mounting holes 28, formed in a closed-end cylindrical magnet holding body 24 made of plastic. By securing other sides 30b of the nonmagnetic metal plates 30 on the magnet holding body 24 with screws at positions which is displaced from the air gaps 14 in the magnetic circuit, the permanent magnets 22 are held stably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art In a conventional magnet movable linear motor 1, as shown in FIGS. 7 and 8, for example, a laminated stator core 2 has an inner yoke 3a on which electromagnetic steel sheets are laminated, and a predetermined gap between the inner yoke 3a and the inner yoke 3a. The outer yoke 3b includes an outer yoke 3b formed by laminating electromagnetic steel sheets arranged with the coil 4, 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 permanent magnets 6 are fitted into the magnet insertion holes 8 perforated in a trapezoidal shape at intervals, and then the permanent magnets 6 are fixedly held by attaching the cylindrical magnet fixing ring 9 to the hollow cylindrical magnet holder 7. That is, the upper side of each of the magnet insertion holes 8 formed in a trapezoidal shape is formed longer than the lower side, and the permanent magnets 6 fitted into the magnet insertion holes 8 are formed in a trapezoidal shape.

[0004]

As a result, the gap for movably disposing the permanent magnet, that is, the air gap of the magnetic circuit formed in the laminated stator core is widened, and as a result, the magnetic flux acting on the permanent magnet is reduced. Since it becomes weak, the thrust of the motor decreases. When a metal cylindrical magnet fixing ring is used, its weight and loss (eddy current loss) increase,
It becomes difficult to improve the performance of the motor.

SUMMARY OF THE INVENTION Accordingly, a main object of the present invention is to provide a magnet capable of securely holding a permanent magnet serving as a mover with a simple structure, reducing the air gap, increasing the thrust of the motor and improving the motor efficiency. Provide a movable linear motor.

[0006]

SUMMARY OF THE INVENTION The present invention relates to 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 a movable magnet linear motor having permanent magnets arranged, the permanent magnets are inserted into a plurality of mounting holes provided in a magnet holding material, and are separated from the air gap of the magnetic circuit by a pair of nonmagnetic metal plates. A movable magnet type linear motor characterized by being held by a holding member.

[0007]

The permanent magnet movably disposed in the gap of the laminated stator core is inserted into each of a plurality of mounting holes provided in the magnet holding member and is separated from the air gap of the magnetic circuit by a pair of non-magnetic metal plates. Because it was held in the magnet holding material with
The air gap can be reduced and the eddy current loss can be reduced.

[0008]

According to the present invention, since the air gap can be reduced, the thrust of the motor increases. Further, since a pair of non-magnetic metal plates are used to fix the permanent magnet, the motor efficiency is improved with almost no eddy current loss as compared with the case of using a heavy metal cylinder or the like.

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.

[0010]

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

The laminated stator core 18 is formed, for example, by laminating electromagnetic steel sheets punched and formed into a predetermined shape from an electromagnetic steel strip. In this embodiment, eight laminated stator cores 18 are formed at 45 °. The stator is arranged in a ring at intervals of.

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, for example, a synthetic resin and has a bottomed cylindrical magnet holder 24, one of which is open.
And the disk center 2 of the magnet holder 24
4a is fixed to the shaft 26 arranged on the central axis CC.

That is, as shown in FIGS. 2 to 4, each permanent magnet 22 is formed, for example, in the shape of a rectangular parallelepiped, while the permanent magnet 22 is inserted and held on the peripheral side surface of the cylindrical magnet holder 24 having a bottom. Eight mounting holes 28 are annularly arranged at 45 ° intervals. The mounting hole 28 has concave steps 28a, 28a formed on both sides of the opening. In addition, one side 30a, 3 of the pair of non-magnetic metal plates 30,
0a is fixed in advance to both sides of the permanent magnet 22 with an adhesive, and in this state, each permanent magnet 22 is connected to the concave step portion 28a,
When the nonmagnetic metal plate 3 is inserted into the mounting hole 28 having the
The other sides 30b, 30b are engaged with and engaged with the concave steps 28a, 28a. Then, using the screws 32, 32, the other side 3
Ob and 30b are fixed by screwing to the concave steps 28a and 28a.

That is, the permanent magnet 22 to which the pair of substantially L-shaped non-magnetic metal plates 30, 30 are adhered is inserted into each mounting hole 28, and the non-magnetic metal plate is located at a position outside the air gap 14 of the magnetic circuit. The plate 30 is screwed to the magnet holder 24 with screws 32.

FIG. 5 shows another embodiment of the present invention in which the permanent magnet 22 is fixedly held on the bottomed cylindrical magnet holder 24.

That is, as shown in FIGS. 5 and 6, the permanent magnet 22 movably disposed in the predetermined gap 14 of the laminated stator core 18 is formed to have a substantially trapezoidal cross section, while a bottom made of plastic is provided. On the peripheral side surface of the cylindrical magnet holder 24, eight mounting holes 28 for fitting the permanent magnets 22 having a substantially trapezoidal cross section are annularly arranged at intervals of 45 °. That is, the permanent magnet 22 is formed such that the outer side (for example, upper side) is longer than the inner side (for example, lower side) in the cross-sectional shape.

Then, a pair of flat non-magnetic metal plates 30,
The permanent magnet 22 is fixed to one end 30a of the magnet 30 by screws 32, 32 at a position outside the air gap 14 of the magnetic circuit, and the other end 30b is fixed to the magnet holder 24 by a screw 32. The plate-like non-magnetic plates 30, 30 and the magnet holder 24 are sandwiched and fixed.

Further, as an embodiment in which the outer side (upper side) of the permanent magnet 22 is formed longer than the inner side (lower side) in the cross-sectional shape, the permanent magnet 22 may be formed in a convex shape in addition to the substantially trapezoidal cross section. In this case, the mounting hole 28 formed in the magnet holder 24 is a stepped hole as shown in FIG. 4 so as to accommodate a permanent magnet having a substantially convex cross section.

In this embodiment, each permanent magnet 22 is stably fixed and held in a mounting hole 28 provided in a bottomed cylindrical magnet holder 24 by using a pair of flat non-magnetic metal plates 30.30. For this reason, the periphery of the mounting hole 28 of the magnet holder 24 has a substantially regular octagonal shape.

As the non-magnetic metal plate 30, for example, a stainless steel plate (SUS304) or a titanium alloy plate is used.

Next, the operation of the movable magnet type linear motor 10 having the above configuration will be briefly described.

In FIG. 1, when an alternating current is applied to the exciting coil 20 mounted on the laminated stator core 18, the magnetic flux generated in the magnetic circuit of the laminated stator core 18 by the current in accordance with the direction of the current causes a gap ( Acting on the permanent magnet 22 disposed in the air gap (14), the permanent magnet 22 moves to the side where the magnetic flux is strengthened, and is displaced rightward or leftward.

Accordingly, the movement of the permanent magnet 22 is transmitted to the shaft 26 located at the center axis CC along the hollow cylindrical magnet holder 24, and the shaft 26 reciprocates as an output shaft. A linear compressor can be realized by connecting a piston that moves in a cylinder of a compressor to the shaft 26, for example.

As described above, in the present invention, the permanent magnets, which are arranged in the predetermined gaps of the laminated stator core and serve as the mover, are formed by bonding a non-magnetic metal plate in advance, for example. Since the bonded permanent magnet is fitted into a mounting hole provided in the magnet holder, and a non-magnetic metal plate is fixed to the magnet holder by a screw at a position outside the air gap of the magnetic circuit. Air gap) can be reduced, and the thrust of the motor increases. Also,
Since the eddy current loss can be reduced, the motor efficiency can be increased.

[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 showing a main part of FIG. 1;

FIG. 3 is an exploded perspective view showing a relationship between a permanent magnet and a non-magnetic metal plate holding the permanent magnet in FIG. 2;

FIG. 4 is an illustrative view showing a cross section of a main part of the movable magnet linear motor having the permanent magnet holding state of FIG. 2;

FIG. 5 is an illustrative view showing main parts of another embodiment corresponding to FIG. 2;

6 is an illustrative view showing a cross section of a main part of a movable magnet linear motor having the permanent magnet holding state of FIG. 5;

FIG. 7 is an illustrative view showing a cross section of a main part of a conventional magnet movable linear motor.

8 is an illustrative view showing a holding state of a permanent magnet in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Magnet movable linear motor 12 ... Inner yoke 14 ... Air gap (air gap) 16 ... Outer yoke 18 ... Laminated stator core 20 ... Excitation coil 22 ... Permanent magnet 24 ... Bottomed cylindrical magnet holder 28 ... Mounting hole 30 ... non-magnetic metal plate 32 ... screw

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Tetsuji Ueda 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5H633 BB08 GG02 GG09 GG17 HH03 HH06 HH07 HH13 HH22 JB06

Claims (7)

[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 is inserted into each of a plurality of mounting holes provided in the magnet holding material and held by the magnet holding material at a position separated from the air gap of the magnetic circuit by a pair of non-magnetic metal plates. A movable magnet type linear motor, characterized in that: 2. The magnet movable linear motor according to claim 1, wherein said permanent magnet has a cross-sectional shape in which a length of an inner side and an outer side is set such that said non-magnetic metal plate side becomes longer. 3. The magnet according to claim 1, wherein said pair of non-magnetic metal plates have an L-shaped cross section, and one side is adhered to both side surfaces of said permanent magnet, and each other side is fixed to said magnet holding member. Magnet movable linear motor. 4. The magnet movable linear motor according to claim 2, wherein said pair of non-magnetic metal plates are flat and one end is locked to said permanent magnet and the other end is fixed to said magnet holding member. 5. A method according to claim 1, wherein said pair of non-magnetic metal plates are fixed to said magnet holding member with screws or an adhesive.
A movable magnet linear motor according to any one of the above. 6. The movable magnet linear motor according to claim 1, wherein said non-magnetic metal plate includes a stainless steel plate or a titanium alloy plate. 7. The movable magnet linear motor according to claim 1, wherein said magnet holding member is made of a synthetic resin and includes a bottomed cylindrical body having one open side.