JPS6240706A - Plastic magnet unit - Google Patents

Abstract

PURPOSE:To form a plastic magnet unit having durability against a heating cycle and a heat shock when a plastic magnet and a metal member are integrally molded by providing a structure that a thermal expansion is buffered to the integrally molded metal member. CONSTITUTION:A cylindrical plastic magnet 11 is integrally formed by outsert molding on the peripheral wall 13 of a bottomed cylindrical metal member 12. The wall 13 of the member 12 is formed with an irregular surface in a wavy shape, so-called 'pectinated shape', and rounded at all sharp corners. The magnet is obtained, for example, by mixing synthetic resin such as thermoplastic resin or thermosetting resin with ferromagnetic material such as ferrite. Thus, thermal expansion or shrinkage can be buffered, and since it can prevent the member 12 from separating, it cam impart extremely high heating cycle and heat shock durability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a plastic magnet device in which a plastic magnet is integrated with a metal member by molding.

[Technical background of the invention and its problems]

Conventionally, as shown in Fig. 2, the bottom surface of an annular plastic magnet 1 obtained by mixing a thermoplastic resin or a thermosetting resin with ferrite has a peripheral edge perpendicular to the bottom surface as shown in Fig. 3. A disk-shaped metal member 2 is embedded and provided integrally. In this case, in order to integrate the plastic magnet 1 and the metal member 2 by molding, the plastic magnet 1 is out-sert molded onto the metal member 2 by pressure molding or injection molding. However, since the plastic magnet 1 has a different coefficient of thermal expansion □ from the metal member 2 and is a brittle material, when obtaining a molded product in which the plastic magnet 1 and the metal member 2 are integrated, heat treatment is required. O1 has the drawback that distortion occurs at the interface between the plastic magnet 1' and the metal member 2 due to cycles and heat shock, causing damage to the plastic magnet 1. I#) ii] The present invention eliminates the above-mentioned drawbacks, and provides the integrally molded golden wing member with a structure that buffers thermal expansion. The purpose of the present invention is to provide a glass magnet 5 meter device that is resistant to heat cycles, heat shocks, and heat cycles.

[Summary of the invention]

The plastic magnet device of the present invention includes a cylindrical plastic magnet obtained by mixing a synthetic resin and a ferromagnetic material, and a bottomed cylindrical metal member having a comb-shaped peripheral wall portion embedded in the plastic magnet. It is equipped with the following.

[Embodiments of the invention]

An embodiment of the present invention will be described in detail below with reference to the drawings.

That is, as shown in FIG. 1, a bottomed cylindrical metal member 12
A cylindrical plastic magnet 1 is integrally formed on the peripheral wall portion 13 by outsert molding. The peripheral wall portion 13 of the metal member 12 is formed in a so-called comb-teeth shape with corrugated irregularities, and all sharp corners are rounded. The plastic magnet can be obtained by mixing a synthetic resin such as a thermoplastic resin or a thermosetting resin with a ferromagnetic material such as ferrite.

That is, in a plastic magnet device in which a plastic magnet 11 having a thermal expansion coefficient different from that of the metal member 12 and which is brittle and the metal member 12 are integrally molded, the contact surface of the plastic magnet 11 with the metal member 12 has a comb-teeth shape. The shape can buffer thermal expansion or contraction and prevent the metal member 12 from falling off, so it can provide extremely high heat cycle resistance and heat shock resistance. .

Table 1 shows the changes in appearance due to heat cycles (-30 to 100°C, 10 times) between the example shown in Fig. 1 and the comparative example shown in Fig. 2. It can be seen that the heat cycle resistance of the embodiment shown in FIG. 1 according to the invention is clearly improved.

Table 1 [Effects of the Invention] As described above, according to the present invention, it is possible to provide a plastic magnet device having extremely high heat cycle resistance and heat shock resistance.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing one embodiment of the present invention, and FIG.
The figure is a partially cutaway perspective view showing a conventional plastic magnet device, and FIG. 3 is a perspective view showing a conventional metal member. DESCRIPTION OF SYMBOLS 11... Plastic magnet, 12... Metal member, 13... Peripheral wall part. Figure 1 Figure 22 Figure 3

Claims (1)

[Claims] It is characterized by comprising a cylindrical plastic magnet obtained by mixing a synthetic resin and a ferromagnetic material, and a bottomed cylindrical metal member having a comb-shaped peripheral wall part embedded in the plastic magnet. Plastic magnet device.