JPH0454847A - Rotor body - Google Patents

Abstract

PURPOSE:To prevent degradation of adhesion due to difference of thermal expansion coefficient of rotor body by employing a grooved yoke in the rotor body. CONSTITUTION:A magnet 2 having outer diameter of 16mm, inner diameter of 13mm and thickness of 5mm is inserted into a grooved 3 yoke 1 precoated with thermosetting epoxy resin and then it is subjected to curing for one hour at 150 deg.C to produce a rotor body. Dimensions of magnet are then measured for the rotor body at the time of insertion of magnet(prior to curing), after heating at l50 deg.C (expanded state), and after cooling. The measurements are shown on table 1 which shows that expansion of the rotor body is suppressed at the time of thermosetting and high adhesion is achieved. Consequently, a rotor body having higher adhesion can be obtained when compared with a conventional yoke having no groove, resulting in a highly reliable rotor.

Description

[Detailed description of the invention] [Industrial application field 1 The present invention relates to a rotor body for a motor.

[Prior art] Many of the rotor bodies for stepping motors currently produced are of the type in which permanent magnets are glued to yoke iron, aluminum, brass, etc. In this case, the strongest adhesive is used. It is common to use easily thermosetting epoxy or acrylic adhesives. When the rotor body is heated to 120-180℃ to harden the adhesive, the yoke and magnet expand, but in reality the thermal expansion coefficients of the magnet and yoke do not match, so when they expand due to heating, there is only a difference in the expansion coefficient. Stress will act between the magnet and the yoke, and when the adhesive hardens and cools and the magnet and yoke contract, that stress will become internal stress in the bond and cause a reduction in bond strength. Become. As a result, the magnet easily separates from the yoke and loses its function as a morph.

[Problem to be Solved by the Invention 1] The present invention is intended to solve such problems, and its purpose is to prevent a decrease in adhesive strength due to differences in thermal expansion coefficients and provide a rotor body with sufficient adhesive strength. It is in.

[Means to solve the problem]

The present invention is characterized in that a grooved yoke is used as a yoke for the rotor body.

The present invention will be described in detail below based on examples.

[Example 1j] A magnet with an outer diameter of 16 mm, an inner diameter of 13 mm, and a thickness of 5+++ m was inserted into the yoke shown in Fig. 1 (clearance with the Iiii1 stone 0.05 mm) coated with a thermosetting epoxy adhesive in advance, The rotor body according to the present invention was obtained by curing at 150° C. for 1 hour. For the rotor body, the dimensions of the magnet when the magnet was inserted (before thermosetting), the magnet dimension when heated to 150° C. (expanded state), and the magnet dimension when cooled were measured. Furthermore, the adhesive strength was measured by the method shown in FIG. For comparison, similar measurements were also performed on a conventional grooveless yoke (Fig. 2). Results first
Shown in the table.

It can be seen that strong adhesive strength can be obtained.

C Example 2] A magnet with an outer diameter of 14 mm, an inner diameter of 12 mm, and a thickness of 5 mm was coated with a thermosetting epoxy adhesive in advance in Figure 1 (1-a).
) The rotor body according to the present invention is attached to a yoke of the type shown in 15 (clearance with the magnet 0.05 mm).
I got 0 pieces. The rotor body undergoes heat shock (1 at -20°C).
After holding the adhesive for 1 hour and then placing it in a thermostat at 150"C for 10 cycles, the adhesive strength was tested. The results are shown in Table 2. For comparison, A similar test was also conducted on the rotor body manufactured by the method.

Table 2 Adhesive strength fkgl Present invention From Table 1 of the conventional method, the present invention shows that the expansion during heat curing is 40-
60 B 14 Table 2 shows that the adhesive strength of the present invention is higher than that of the conventional method, and there is less variation.

[Effects of the Invention J As described above, the present invention has made it possible to obtain a rotor unit with stronger adhesive strength than conventional grooveless yoke and to provide a highly reliable rotor.

[Brief explanation of drawings]

1(a) and 1(C) are views showing the rotor body according to the present invention, FIG. 1(b) is a cross-sectional view taken along line A-A' in FIG.
Figure (d) is a sectional view taken along line BB' in Figure 1 (c). 1...Yoke 2...Magnet 3...Groove Figure 2(a) shows the rotor body according to the conventional method, Figure 2(b) shows Figure 2(a) (7)C- C' sectional view. 2...Magnet Figure 3 shows a method of measuring adhesive strength, in which the magnet of the rotor body is supported on a support, and the adhesive strength is measured by applying force to the upper surface of the yoke until the magnet comes off.・Strength measuring device main body ・Pressure terminal ・Support ・Magnet ・Yoke and above Applicant: Seiko Epson Co., Ltd. Agent Patent attorney Kizobe Suzuki (1 other person) 1...Yoke (a) (C) Figure 1 (a) Figure 2

Claims (1)

[Claims] A rotor body obtained by bonding ring-shaped magnets to a yoke using a thermosetting adhesive is characterized by using a yoke with grooves to absorb internal stress generated during bonding as the yoke. rotor body.