JP2000083364A - Movable core linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a movable core linear motor which can be made thin while reducing copper loss and improving efficiency. SOLUTION: Fixed section comprises a stator core frame 16 having substantially U-shaped cross-section defined by an outer part 16a, an inner part 16b and a bottom part 16c coupling them at one end parts thereof, permanent magnets 22, 24 secured to the opposite faces of the outer and inner parts 16a, 16b, and a coil 18 disposed in the inner space of the stator core frame 16. A movable section 14 comprises a tubular bottomed movable holding body 26 which penetrates the shaft part 28 and a movable core 30 fixed to the open end part of the holding body 26, wherein the movable core 30 is disposed in the gap between the permanent magnets 22, 24 of the stator core frame 16. According to the structure, to length of the wire used for the coil 18 can be shortened and since copper loss can be reduced, motor efficiency is improved. Furthermore, the motor can be made thin because the thickness of the coil can be decreased in the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable core type linear motor, and more particularly to a movable core type linear motor in which a movable core which can be displaced in the axial direction is disposed in a gap surrounded by permanent magnets.

[0002]

2. Description of the Related Art A conventional movable iron core type linear motor 1
As shown in FIG. 6 and FIG.
A stator 4 is formed by laminating a stator core 3 having a plurality of stator poles 2, a coil 5 is wound around each stator pole 2, and a permanent magnet 6 is provided on an end face of each stator pole 2. It is mounted and stored in a stator case (not shown). This permanent magnet 6
Is formed by joining two permanent magnet pieces 6a and 6b having magnetization vectors opposite to each other in the radial direction in the axial direction. On the other hand, a movable iron core 9 fixed to a shaft portion 8 is arranged in a gap 7 of the stator 4. The movable core 9 is formed by laminating circular high-permeability members parallel to a plane perpendicular to the axial direction, for example, magnetic steel plates, and is located in a space region surrounded by the permanent magnets 6.

In such a configuration, when a current is applied to the coil 5, a magnetic flux generated by the current in accordance with the direction of the current strengthens one 6a of the adjacent permanent magnets 6 and weakens the other one 6b. A force such that the movable core 9 moves on the side where the magnetic flux is strengthened acts, and the shaft portion 8 moves rightward or leftward as indicated by the arrow in the figure.

[0004]

However, in the movable iron core type linear motor having such a structure, the coil 5 is divided into a plurality of parts and arranged on each stator pole 2, so that the wire used for the coil becomes longer. However, there is a problem that the copper loss increases accordingly. Also, it is difficult to make the entire motor thinner due to the thickness of the coil occupying in the axial direction. Further, when the movable iron core is formed by laminating magnetic steel sheets, as shown in FIG. 8, since the permanent magnet 6 and the movable iron core 9 are close to each other, the permanent magnet 6 is moved by the flow of the loop-shaped magnetic flux. A radial force for attracting the iron core 9 acts, which is a factor that impairs the movable force.

[0005] Therefore, a main object of the present invention is to provide a movable iron core type linear motor which has a small copper loss, is efficient and can be made thin.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a plurality of fixing members which are formed of a magnetic member and have a substantially U-shaped cross section at an outer portion, an inner portion, and a bottom portion connecting one end of the outer portion and the inner portion. A core core, one coil wound so as to pass between an outer portion and an inner portion of each stator core frame, permanent magnets respectively fixed to opposing surfaces of the outer portion and the inner portion,
And a movable core supported by a movable holder that can be displaced in the axial direction and disposed in a gap surrounded by permanent magnets.
This is a movable core linear motor.

[0007]

Since one coil is wound around the inner space of a plurality of stator core frames formed into a substantially U-shaped cross section by the outer portion, the inner portion, and the bottom portion connecting one end of both portions. , The length of the wire used for the coil can be shortened,
Also, the axial thickness of the coil is reduced.

[0008]

According to the present invention, the length of the wire forming the coil is reduced, the copper loss can be reduced, and the efficiency of the motor is improved. Further, the thickness of the coil occupying in the axial direction is reduced, so that the motor can be reduced in thickness. 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 drawings.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A movable iron core type linear motor 10 according to this embodiment shown in FIGS. 1 to 3 comprises a fixed portion 12 and a movable portion 14 movable in the left and right directions shown by arrows with respect to the fixed portion 12. I do. The fixing portion 12 includes four stator core frames 16 formed in a substantially U shape, and an outer portion 1 of each stator core frame 16.
1 wound so as to pass between the inner portion 6a and the inner portion 16b
Coils 18 and their stator core frames 16
And a bottomed donut-shaped fixed case 20 made of a non-magnetic material such as stainless steel, which is disposed opposite to and stored at an interval of °.

Each stator core frame 16 is made of a magnetic material such as low silicon steel, and has an arcuate outer portion 16a, an arcuate inner portion 16b, and an outer portion connecting one end of both portions 16a and 16b. Bottom portion 16c integral with 16a
And an arc-shaped permanent magnet 22 and an inner portion 16 fixed to the inner surface of the other end of the outer portion 16a.
arc-shaped permanent magnet 24 fixed to the outer surface of the other end of b
including. The permanent magnets 22 and 24 are composed of a pair of permanent magnet pieces 22a and 22 having magnetization vectors that are radially opposite to each other.
b and 24a, 24b are all fixed in the outer part 16a and the inner part 16b in the axial direction. The outer portion 16a and the inner portion 16b are formed by stacking magnetic steel plates parallel to a radial surface passing from the central axis to the center of each portion. The coil 18 is wound around an annular bobbin 26 having a U-shaped cross section, and is disposed so as to occupy the bottom space of each stator core frame 16.

The movable portion 14 which is displaced in the axial direction has a bottomed cylindrical movable holding member 28, a cylindrical fixed member projecting from the bottom of the movable holding member 28 and accommodating and holding the stator core frame 16. A cylindrical movable iron core 3 fixed to a shaft portion 30 penetrating the inside of the case 20 and an open end of the movable holding member 28
2 inclusive. The movable iron core 32 is formed by laminating a plurality of ring-shaped magnetic steel plates or the like in the axial direction, and has a thickness of a pair of permanent magnet pieces 22a and 22b constituting the permanent magnet 22, as shown in FIG. The dimension is shorter than the sum of the lengths.

In this configuration, when a current is applied to the coil 18, the magnetic flux generated by the current in accordance with the direction of the current strengthens the adjacent ones 22a and 24a of the adjacent permanent magnets 22 and 24 and the remaining ones In order to weaken the magnetic fluxes 22b and 24b, a force such that the movable iron core 32 moves to the side where the magnetic flux is strengthened acts, and the movable portion 14 moves rightward or leftward.

The movable iron core 32 is disposed in a gap between the two permanent magnets 22 and 24, as shown in FIG. 4. The movable iron core 32 is made of a magnetic steel plate 34 having a high magnetic permeability in the axial direction. When the non-magnetic plates 36 having a low thickness are alternately laminated, the movable iron core 32 is attached to the permanent magnets 22 and 24.
The flow of the magnetic flux attracted to the inside of the movable iron core 32 is completely blocked by the non-magnetic plate 36, and the magnetic flux passes through in the direction of the opposing permanent magnet. As a result, the magnetic flux of the permanent magnets 22 and 24 with respect to the movable iron core 32 is reduced, the radial force is reduced, and the loss of power is also reduced, so that the movable portion 14 moves smoothly. In addition, a holding mechanism such as a bearing is also facilitated. For example, as shown in FIG. 8, when the movable iron core is compared with a configuration in which only a magnetic steel sheet is laminated, the radial force is about half.

In the above-described embodiment, the outer portion 16a and the inner portion 1 of each stator core frame 16 are formed.
Although 6b is formed in an arc shape, the same effect can be obtained by forming it in a flat shape as shown in FIG. In this case, the permanent magnets 22 and 24 are also formed in a flat shape, and the shapes of the movable holding body 28 and the movable iron core 32 are also changed to rectangular shapes.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a schematic configuration of a movable iron core type linear motor according to an embodiment of the present invention.

FIG. 2 is an illustrative view showing a cross section of a main part of the embodiment shown in FIG. 1;

FIG. 3 is an illustrative view showing a cross section of a main part corresponding to AA of the embodiment shown in FIG. 2;

FIG. 4 is an illustrative view showing an enlarged main part in FIG. 2;

FIG. 5 is an illustrative view of another embodiment corresponding to FIG. 3;

FIG. 6 is a plan view of a main part of a conventional movable core linear motor.

FIG. 7 is an illustrative view showing a relevant part in FIG. 6;

FIG. 8 is an illustrative view for comparison with the embodiment in FIG. 4;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Movable iron core linear motor 12 ... Fixed part 14 ... Movable part 16 ... Stator iron frame 16a ... Outer part 16b ... Inner part 16c ... Bottom part 18 ... Coil 20 ... Fixed cases 22,24 ... Permanent magnet 28 ... Movable holding Body 30… Shaft part 32… Movable iron core 34… Magnetic steel plate 36… Non-magnetic plate

Claims (4)

[Claims] 1. A plurality of stator core frames formed of a magnetic member and formed in an approximately U-shaped cross section at an outer portion, an inner portion, and a bottom portion connecting the outer portion and one end of the inner portion. One coil wound so as to pass between the outer portion and the inner portion of the stator core frame, permanent magnets respectively fixed to opposing surfaces of the outer portion and the inner portion, and axial displacement A movable iron type linear motor, comprising a movable iron core supported by a movable movable holder and disposed in a gap surrounded by the permanent magnet. 2. The movable iron core type linear motor according to claim 1, wherein said movable iron core includes a magnetic member laminated in an axial direction. 3. A movable iron core type linear motor according to claim 1, wherein said movable iron core includes a non-magnetic member partially in an axial direction. 4. The movable core linear motor according to claim 3, wherein said movable core is formed by laminating a magnetic member and a non-magnetic member in an axial direction.