JP4802511B2 - Linear motor stator and linear motor - Google Patents

Description

  The present invention relates to a stator for a linear motor, and more particularly to a stator for a linear motor in which a plurality of permanent magnets are arranged on a metal plate, and a linear motor using this stator.

A stator in a conventional linear motor has a structure in which a plurality of permanent magnets are arranged in parallel with different magnetic poles alternately, and fixed on a metal flat plate with a predetermined interval. For fixing these permanent magnets to the metal flat plate, an adhesive is used, and the periphery of the bonded permanent magnet is molded with a mold resin (for example, see Patent Document 1).
Further, the conventional linear motor stator is sealed with resin in order to prevent the permanent magnets protruding on the surface of the metal flat plate from being damaged when the linear motor is assembled or used.

JP 2002-369490 A (page 2-3, FIG. 2)

Linear motors are used in high-precision positioning devices, and high flatness is required for linear motor stators. However, since the linear expansion coefficient of the metal plate, permanent magnet, and sealing resin that form the stator for the linear motor is different, the permanent magnet is fixed on the metal plate, and the permanent magnet on the metal plate is heated and cured. When the linear motor stator is returned from the curing temperature of the sealing resin to room temperature, warping occurs.
In addition, in order to reduce the size and weight of linear motors, the thickness of the metal plate on which permanent magnets are mounted and the sealing resin are becoming thinner, and in order to improve the productivity of linear motors, It is necessary to mount as many permanent magnets as possible, and the length of the moving direction of the metal plate mover used for the linear motor stator is getting longer, and the problem is that the linear motor stator warps more. was there.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a metal plate for mounting a permanent magnet and a metal plate for mounting a permanent magnet even when the sealing resin is thin. Even if the length of the mover in the moving direction is long, a linear motor stator that is small in warpage, excellent in flatness, and excellent in long-term reliability, and a linear motor using this stator are obtained. Is.

A stator for a linear motor according to the present invention includes a metal plate, a plurality of permanent magnets that are arranged in parallel and fixed on the same surface of the metal plate at intervals and with different magnetic poles alternately, and a permanent magnet And the resin for sealing is rubber-like in the operating temperature range, and the hardness (JIS) at 25 ° C. after the curing is completed is A−. 10
In addition to being in the range of A-80 , the resin does not contain 10% or more of a component such as a plasticizer that scatters at a high temperature .

  Further, the linear motor of the present invention is arranged to be reciprocally movable in the longitudinal direction of the stage, facing the stage, the linear motor stator mounted on the stage, and the linear motor stator. A mover is provided.

  According to this invention, the metal plate and the sealing resin are thin and thin, and even if the length is long, it is possible to obtain a stator for a linear motor that is small in warpage and undulation and excellent in flatness.

  Further, according to the present invention, since the resin does not contain 10% or more of a component that scatters at high temperature such as a plasticizer, the scattered matter scatters depending on the temperature during product operation, causing the resin to shrink or increase in hardness. It does not cause cracks.

Embodiment 1 FIG.
1A and 1B are a schematic cross-sectional view (a), a schematic top view (b), and a side cross-sectional view (c), respectively, of a linear motor stator according to Embodiment 1 of the present invention. The top schematic view (b) also shows a state where a part of the sealing resin is removed and the metal plate and the permanent magnet can be seen.
As shown in FIG. 1, a linear motor stator (abbreviated as “stator”) 1 includes a long metal plate 2, a permanent magnet 3 provided on the surface of the metal plate 2, and a sealing resin 4. Is formed.
A plurality of permanent magnets 3 are arranged in parallel along a direction substantially perpendicular to the longitudinal direction of the metal plate 2 so that the magnetic poles are alternately different, and are arranged on the metal plate 2 at a predetermined interval. Is provided. The sealing resin 4 is provided so as to cover the permanent magnet 3 and the surface of the metal plate 2 on which the permanent magnet 3 is provided.
And the stator 1 is used by connecting with a longitudinal direction as needed individually or in plurality.

Examples of the metal plate 2 used in the present embodiment include a steel plate from the viewpoint of workability and availability.
Further, examples of the permanent magnet 3 used in the present embodiment include neodymium magnets and ferrite magnets. However, the permanent magnets 3 are not particularly limited as long as they have a strong magnetic force.
The sealing resin 4 used in the present embodiment is a resin that is rubbery in the operating temperature range (for example, 0 ° C. to 150 ° C.) in which the linear motor is used.
Specific examples of the resin that is rubbery in the operating temperature range include epoxy resins, silicone resins, urethane resins, and thermoplastic elastomers. If it is not rubbery in the operating temperature range, the stress due to thermal strain after completion of curing increases and warpage increases. In other words, if the glass transition temperature is higher than 10 ° C., the stress due to thermal strain after completion of curing increases and warpage increases.

Moreover, as for sealing resin 4 used by this Embodiment, it is desirable that the hardness (JIS) in 25 degreeC after completion of hardening is A-80 or less. If the hardness (JIS) is greater than A-80, the stress due to curing shrinkage at the time of curing or the stress due to thermal strain after the curing is increased, and warping is increased.
If the hardness (JIS) is smaller than A-10, the adhesive strength with the metal plate 2 or the permanent magnet 3 is low, and problems such as poor surface tackiness occur even when curing is completed.

  Moreover, it is desirable that the sealing resin 4 used in the present embodiment does not contain 10% or more of a component such as a plasticizer that scatters at a high temperature. If the scattering component is contained in the resin in an amount of 10% or more, the scattered matter is scattered depending on the temperature during the operation of the product, causing the resin to shrink or increase in hardness, thereby causing cracks.

In addition, the sealing resin 4 used in the present embodiment can be blended with an inorganic powder in order to reduce shrinkage and improve strength and elastic modulus.
Examples of inorganic powders include fused silica, crystalline silica, olivine, wollastonite, cordierite or forsterite, alumina, hydrated alumina, aluminum hydroxide, hollow glass beads, glass fibers, and oxidation. Magnesium, titanium oxide, calcium carbonate, magnesium carbonate, dolomite, talc, potassium titanate fiber, calcium hydroxide, magnesium hydroxide, antimony trioxide, anhydrous gypsum, barium sulfate, boron nitride, silicon carbide, aluminum fluoride, fluoride Examples of the powder include calcium, magnesium fluoride, and aluminum borate. The inorganic powders can be used alone or in any combination.

Next, the present invention will be described in more detail with reference to examples.
Example 1.
The members constituting the linear motor stator 1 include an S45C steel plate as the metal plate 2, a neodymium magnet {NEOREC42SH: manufactured by TDK Co., Ltd.} as the permanent magnet 3, a urethane resin {SU- 3600A / SU-3600B: Sanyu Rec Co., Ltd.} is used. Table 1 shows the dimensions of the metal plate 2 and the permanent magnet 3.

  The linear motor stator 1 is manufactured as follows. The 42 permanent magnets 3 are fixed to the metal plate 2 in parallel with the width direction of the metal plate 2 with an interval of 4 mm. At this time, the permanent magnets 3 at both ends are provided at a position 2 mm from each end in the longitudinal direction of the metal plate 2. Next, the metal plate 2 provided with the permanent magnet 3 is placed in a mold surrounding the metal plate 2, and the sealing resin 4 is placed in the mold up to a height of 0.5 mm from the upper surface of the permanent magnet 3. The urethane resin is injected and heated at 80 ° C. for a predetermined time to cure the urethane resin to obtain the linear motor stator 1.

  The obtained linear motor stator 1 was placed on a horizontal surface plate at 20 ° C., and the maximum gap between the surface plate surface and the lower surface of the metal plate 2 was measured to evaluate the flatness of the linear motor stator 1. The obtained maximum gap value is shown in Table 3 together with the glass transition temperature (Tg) and JIS-A hardness of the sealing resin 4 used in this example.

  A cylindrical resin lump was prepared, and the obtained resin lump was exposed to high temperature to evaluate the change in weight from the initial stage. FIG. 2 is a schematic cross-sectional view (a) and a schematic top view (b) of the obtained resin mass. Table 2 shows the dimensions of the resin mass obtained. The obtained weight change is shown in Table 3 together with the glass transition temperature (Tg) and JIS-A hardness of the sealing resin 4 used in this example.

  After the obtained linear motor stator 1 is exposed to high temperature, the heat cycle of + 100 ° C. to −20 ° C. is repeated 5 times, and the presence or absence of cracks or the like is determined for the glass transition temperature of the sealing resin 4 used in this example. The results are shown in Table 3 together with (Tg) and JIS-A hardness.

  A SUS 303 plate was bonded with resin, the tensile shear strength was measured, and the adhesive strength of the resin was evaluated. The obtained adhesive strength is shown in Table 3 together with the glass transition temperature (Tg) and JIS-A hardness of the sealing resin 4 used in this example.

Example 2.
As shown in Table 3, a linear motor stator 1 is obtained in the same manner as in Example 1 except that urethane resin {MU-102A / MU102B: Nippon Pernox Co., Ltd.} is used as the sealing resin 4. The planarity of the obtained linear motor stator 1 was evaluated in the same manner as in Example 1. The obtained value of the maximum gap is shown in Table 3 together with the glass transition temperature (Tg) and JIS hardness of the sealing resin 4 used in this example.

Example 3.
As shown in Table 3, the linear resin stator 1 was obtained in the same manner as in Example 1 except that an epoxy resin {XM-2437 / HY-690: Nippon Pernox Co., Ltd.} was used as the sealing resin 4. obtain. The planarity of the obtained linear motor stator 1 was evaluated in the same manner as in Example 1. The obtained maximum gap value is shown in Table 3 together with the glass transition temperature (Tg) and hardness of the sealing resin 4 used in this example.

Example 4
A linear motor stator 1 is obtained in the same manner as in Example 1 except that urethane resin {UF-110A / UF-110B: Sanyu Rec Co., Ltd.} is used as the sealing resin 4 as shown in Table 3. . The planarity of the obtained linear motor stator 1 was evaluated in the same manner as in Example 1. The obtained maximum gap value is shown in Table 3 together with the glass transition temperature (Tg) and hardness of the sealing resin 4 used in this example.

Example 5.
A linear motor stator 1 is obtained in the same manner as in Example 1 except that the urethane resin {SU-3001A / SU-3001B: Sanyu Rec Co., Ltd.} is used as the sealing resin 5 as shown in Table 3. . The planarity of the obtained linear motor stator 1 was evaluated in the same manner as in Example 1. The obtained maximum gap value is shown in Table 3 together with the glass transition temperature (Tg) and hardness of the sealing resin 4 used in this example.

Example 6
As shown in Table 3, a linear motor stator was used in the same manner as in Example 1 except that urethane resin {XN-2248 / XY-2233-1: Nippon Pernox Co., Ltd.} was used as sealing resin 5. Get one. The planarity of the obtained linear motor stator 1 was evaluated in the same manner as in Example 1. The obtained maximum gap value is shown in Table 3 together with the glass transition temperature (Tg) and hardness of the sealing resin 4 used in this example.

Comparative Example 1.
Example except that urethane resin {SU-1000A / SU-1000B: Sanyu Rec Co., Ltd.} having a hardness of JIS A-80 or higher and not rubbery as shown in Table 3 was used as the sealing resin 6. 1 to obtain a linear motor stator 1. The planarity of the obtained linear motor stator 1 was evaluated in the same manner as in Example 1. The obtained maximum gap value is shown in Table 3 together with the glass transition temperature (Tg) and hardness of the sealing resin 4 used in this example.

Comparative Example 2
Example 1 except that a urethane epoxy resin {XNR5002 / XNH5002: Nagase ChemteX Corp.} that has a hardness of JIS A-80 or higher and is not rubbery in the operating temperature range as shown in Table 3 was used as the sealing resin 7. In the same manner as described above, the linear motor stator 1 is obtained. The planarity of the obtained linear motor stator 1 was evaluated in the same manner as in Example 1. The obtained maximum gap value is shown in Table 3 together with the glass transition temperature (Tg) and hardness of the sealing resin 4 used in this example.

  As shown in the examples of Table 3, when a sealing resin that is rubbery in the operating temperature range is used, the metal plate and the sealing resin are thin, and even if they are thin and long, warping and undulation are small. A stator for a linear motor having excellent flatness can be obtained. When these linear motor stators are used, a thin and long linear motor can be realized.

  The stator for a linear motor according to the present invention is suitable for use in a linear motor including a stator in which a plurality of permanent magnets are arranged on a metal plate.

It is a cross-sectional schematic diagram (a), a top schematic diagram (b), and a side cross-sectional view (c) of the stator for a linear motor according to Embodiment 1 of the present invention. It is the cross-sectional schematic diagram (a) and upper surface schematic diagram (b) of the resin lump used by weight change evaluation by high temperature exposure of resin in Embodiment 1 of this invention.

Explanation of symbols

  1 Stator for linear motor, 2 Metal plate, 3 Permanent magnet, 4 Sealing resin

Claims (2)

Provided with a metal plate, a plurality of permanent magnets arranged in parallel and spaced apart on the same surface of the metal plate so that the magnetic poles are alternately different, and a resin for sealing the permanent magnet The stator for a linear motor, wherein the resin to be sealed is rubbery in the operating temperature range, and the hardness (JIS) at 25 ° C. after completion of curing is within the range of A-10 to A-80. In addition, the linear motor stator is characterized in that the resin does not contain 10% or more of a component such as a plasticizer that scatters at a high temperature . A stage, a stator for a linear motor according to claim 1 placed on the stage, a mover facing the linear motor stator and reciprocally movable in a longitudinal direction of the stage; A linear motor comprising

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