JPH01202147A - Linear motor - Google Patents

Abstract

PURPOSE:To make an apparatus non-contact and noiseless by causing a magnetic body wound by a superconducting coil and a magnet to face each other as bearing means moving a movable element while maintaining a constant gap from a stator forming a linear motor. CONSTITUTION:A slit member 16 having slits at a constant pitch is provided on the top face of a plate member 15 in the longitudinal direction perpendicular to the surface of this sheet of paper. In the manner of facing said slit member 16, a permanent magnet 7 and a pair of magnetic cores 6a, 6b provided with three groups of magnetic poles having pole teeth are formed into an integral body and thereafter provided with a three-phase armature winding 12 to form a movable element 10. On both sides of said plate member 15, an electromagnet 2 obtained by winding a superconducting ceramic coil 1 round a magnetic body 2 is provided via a magnetic shielding plate 3. On both sides of said movable element 10, a magnet 4 is provided via said magnetic shielding plate 5 in the manner of corresponding to said electromagnet 2. When power is applied to the coil 1, the movable element 10 levitates by a powerful magnetic force. Thus, an apparatus is suitable for printer and the like, because it is made noncontact and noiseless and its long life is accomplished.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to linear motors used in printers and plotters used, for example, to print out information from a computer.

2. Description of the Related Art In recent years, the number of printers and plotters used to print out information from computers that use linear motors for linear motion has increased.

An example of the basic configuration of a linear motor will be explained with reference to FIG.

This linear motor is composed of a stator 9 and a movable element 10 that is movable in the longitudinal direction of the stator 9 while opposing the stator 9 with a fixed gap by supporting means such as ball bearings. It is a three-phase linear motor. The stator 9 is made up of a plate member (guiding support member) 15 that guides and supports the mover 10 made of a magnetic material such as pure iron, and a magnetic member such as permalloy disposed on the plate member 15.
and a slit member 16 having a plurality of slits at a constant pitch in the longitudinal direction.
6 is attached to form the magnetic pole teeth.

The movable element 10 includes a pair of magnetic cores 6 a * 6 b and a permanent magnet 7 , which are provided with three groups of magnetic poles each having a concavo-convex portion (magnetic pole teeth), facing the slit member 16 of the stator 9 . It is formed by integrating the three-phase armature winding 12.

Further, the movable element 10 is provided with a non-contact position detection block 11 in which three reflective optical sensors are built in, and when the movable element 10 moves on the stator 9, the slit member 16 Three-phase position signals are output based on changes in the amount of reflected light depending on the presence or absence of slits, and the power supply to the three-phase armature windings is controlled without contact using these position signals. In the linear motor having magnetic pole teeth as described above, in order to enable the mover 10 to move on the stator 9 while maintaining a constant gap, a plurality of pole bearings are used, as shown in FIG. As shown, since ball bearings run on the pole bearing travel portions 17 on both sides of the slit member 16 on the plate member 15, it is usually necessary to perform wear-resistant treatment such as hard chrome plating.

Conventionally, the entire surface of the plate member 15 is plated with hard chrome, and then the slit member 16 is bonded. Therefore, in order to prevent the motor characteristics from being impaired by the magnetic resistance of the plate member 15 and the slit member 16, the plating thickness is several microns.
m or less.

This will be explained in more detail with reference to FIG. 4, which shows a cross section of a conventional example.

Hard chrome plating 18 is applied to the entire surface of the plate member 15 with a uniform thickness, and the slit member 16 is bonded with a single adhesive.

Problems to be Solved by the Invention However, in such a configuration, the magnetic path of the lines of magnetic force generated from the permanent magnet 7 and the armature winding 12 forms a loop as shown by the arrow in the figure. , the magnetic resistance in the magnetic path increases, resulting in a disadvantage that the driving force of the motor decreases.

On the other hand, if the plating thickness is too thin, the mechanical life of the ball bearing 20 as a running surface will be shortened due to the inability to perform surface treatment to ensure good adhesion between the hard chrome plating and the plate member 15. .

It also has the disadvantage of being noisy when running.

The present invention solves these problems by extending the life of the running surface and reducing noise during running.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention includes a magnetic body around which a superconducting coil is wound as a bearing means, and a magnet facing the magnetic body with a fixed gap therebetween. be.

Effect: With the above configuration, a constant gap can be maintained between the stator and the movable element using the magnetic material wrapped around the superconducting coil as a bearing means and the repulsive force of the magnet, making the running of the linear motor noiseless. be able to.

Example FIG. 1 shows an embodiment of the present invention.

In addition, a magnetic body 2 around which a superconducting ceramic coil 1 is wound as a bearing device, a shielding plate 3 made of superconducting ceramics that shields the magnetic flux emitted from the magnetic body 2, a magnet 4 facing the magnetic body 2, and a shielding plate that shields the magnetic flux emitted from the magnet 4. The structure is the same as the conventional structure except for the shielding plate 5 made of superconducting ceramics, and the explanation thereof will be omitted. In FIG. 1, a superconducting ceramic coil 1 wound around a magnetic material 2 is used to form a closed loop so that a persistent current flows, and has the function of making the magnetic material 2 a strong magnet.

The shielding plate 3 is made of a superconducting ceramic plate, and shields the magnetic flux emitted from the magnetic body 2, thereby protecting the guide support member 15 from magnetic flux noise.

The shielding plate is also made of a superconducting ceramic plate and shields the magnetic flux emitted from the magnet 4 and protects the movable element 10 from magnetic flux noise. Therefore, the quality of the linear motor can be improved.

At this time, if the upper surface of the magnetic body 2 is the north pole, the lower surface of the magnet 4 is the north pole.

Further, the relationship between the gap T between the stator 9 and the movable element 10 and the gap t between the magnetic body 2 and the magnet 4 of the bearing section is set to be Tit.

In addition, as another embodiment, for example, when the upper surface of the magnetic body 2 and the lower surface of the magnet 4 have an inclination as shown in FIG. 2, further stability and near motor running can be realized.

The following superconducting materials are used in the linear motor.

As a material exhibiting superconductivity at 90%, for example, YBa2C
u307-δ can be used. During production, first the raw material powder is crushed and mixed. It is baked at 900°C in air for S hours and then pulverized, and the process is repeated three times to improve uniformity.

The powder is compacted and sintered by heating in air or oxygen for 5 hours at 930 DEG to 950 DEG C. and cooled in a furnace.

5rYBa2C is a material that exhibits superconductivity near room temperature.
u307-δ is known. (Ihara et al., JAPAN
ESE JOURNAL OF APPLIED
PHYSIC8), Vol, 26°No, 8. Au
Gust, 1987. When manufacturing PP, 167,
First, the raw material powder is crushed and mixed. It is 920″C1
After firing in air for 5 hours, the mixture is crushed and repeated three times.

The powder is compacted, sintered by heating at 1000° C. in air for 5 hours, and cooled in a furnace. The sintered body thus produced exhibits superconductivity even at 338K (65°C).

Effects of the Invention As is clear from the above description, the present invention provides the following effects.

(1) Since the repulsive force of a non-contact magnet is used as a bearing means, a noiseless and high quality near motor can be obtained.

(2) Since the repulsive force of a non-contact magnet is used as a bearing means, there is no wear due to running (a long-life linear motor can be obtained).

(3) By using a superconducting ceramic plate for magnetic shielding, it is possible to obtain a near motor with excellent quality and no magnetic noise to the mover and stator.

As a result of (1) to (3) above, the quality of the linear motor can be improved and its life can be significantly extended.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a linear motor showing a first embodiment of the present invention, FIG. 2 is a sectional view of a linear motor according to another embodiment of the invention, and FIG. 3 is a diagram of a conventional linear motor. Fourth
The figure is a sectional view of a conventional linear motor. 1...Superconducting ceramic coil, 2...
...Magnetic material, 3,5...Magnetic shielding plate, 4...
...Magnet, 15...Plate member, 16.
...Slit member. Name of agent: Patent attorney Toshio Nakao and 1 other person 1--Isso Shodenhana, Kusumi Kuskoi 12-1 Magnetic material 3.5-*tAtJk Figure 1
4-11 Macnet Figure 2 Figure 3

Claims (1)

[Claims] A stator made of a magnetic material having a plurality of slits at a constant pitch in the longitudinal direction, and a movable element having a group of magnetic pole teeth and a plurality of armature windings facing the magnetic pole teeth of the stator with a constant gap. a magnetic body wound with a superconducting coil as a bearing means that maintains a constant gap between the movable element and the stator and allows the movable element to move along the stator; A linear motor equipped with magnets facing each other with a gap between them.