JP2000324733A - Motor magnet retaining structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor magnet retaining structure which can protect magnets from damages. SOLUTION: U-shaped springs 40 are provided between a pair of magnets 20. Since the fixed parts 41 of the springs 40 are covered with synthetic resin 42 with relatively soft elasticity and heat-resistance performance. Therefore, the magnets 20 are brought into contact with the springs 40 with the synthetic resin 40 therebetween. Furthermore, the bias forces of the springs 40 are applied to the center parts 21 of the pair of magnets 20. As a result, even if the spring constant of the spring 40 is large, the bias forces applied to the magnets 20 are relaxed by the synthetic resin. Therefore, the magnets 20 with not break or crack from impact at assembling and from aging, so that the magnets 20 can be protected from damages. Furthermore, the magnets 20 can be retained surely with a simple construction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet holding structure for a motor.

[0002]

2. Description of the Related Art As a structure for holding a magnet in a motor, a U-shaped spring 110 is provided on the inner peripheral surface of a yoke 100 as shown in FIG.
There is a structure in which the magnet 120 is fixed between the magnets 20.

[0005] As shown in FIG. 5B, there is also a structure in which a spring 111 formed by bending a fixing portion of a U-shaped spring is disposed between a pair of magnets 120 to fix the magnets 120.

[0004]

However, in a structure in which U-shaped springs 110 and 111 are arranged and fixed between a pair of magnets 120, the magnet 120 and the spring 11
Since the magnets 120 and 111 are in direct contact with each other, the magnet 120 is not easily stabilized. In addition, the magnet 120 may be cracked or chipped due to impact or aging during assembly.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a motor magnet holding structure capable of preventing damage to a magnet.

[0006]

According to the first aspect of the present invention, there is provided a magnet holding structure for a motor for holding a plurality of magnets on an inner peripheral surface of a cylindrical yoke. An urging means for holding the magnet on the inner peripheral surface of the yoke is provided, and a buffer means is interposed between the urging means and the magnet.

Therefore, according to the first aspect of the present invention,
The urging force of the urging means applied to the magnet is reduced by the buffer means. In the invention described in claim 2, in the magnet holding structure of the motor for holding a plurality of magnets on the inner peripheral surface of the cylindrical yoke, there is provided a biasing means for holding the magnet on the inner peripheral surface of the yoke, At least a portion of the urging means that comes into contact with the magnet was covered with a synthetic resin.

Therefore, according to the second aspect of the present invention,
The urging force of the urging means applied to the magnet is reduced by the synthetic resin. According to a third aspect of the present invention, in the magnet holding structure of the second aspect, the synthetic resin is nylon or epoxy.

Therefore, according to the third aspect of the present invention,
Nylon or epoxy alleviates the urging force of the urging means applied to the magnet. According to a fourth aspect of the present invention, in the motor magnet holding structure according to any one of the first to third aspects, the biasing unit biases a central portion of the magnet.

Therefore, according to the invention described in claim 4,
Damage to the magnet is prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the motor 1 includes a yoke 10, a pair of magnets 20, and a rotor 30.

The yoke 10 is made of a metal and has a substantially cylindrical shape. The pair of magnets 20 are formed in a curved shape along the inner peripheral surface of the yoke 10, and are disposed on the inner peripheral surface of the yoke 10. The rotor 30 is disposed between the pair of magnets 20.

A U-shaped spring 40 is disposed between the pair of magnets 20 as urging means.
The fixing portion 41 of the spring 40 has a relatively soft elasticity and is covered with a synthetic resin 42 (for example, nylon, acrylic, polyester, epoxy or the like) as a heat-resistant buffer. For this reason, magnet 2
0 contacts the spring 40 via the synthetic resin 42. In addition, the urging force of the spring 40 is applied to the central portions 21 of the pair of magnets 20. As a result, even if the spring constant of the spring 40 is large, the magnet 2
The biasing force applied to zero is reduced. Therefore, the magnet 20 does not break or chip due to an impact or aging during assembly. Therefore, damage to the magnet 20 can be prevented. Moreover, the magnet 20 can be securely held with a simple configuration.

Further, the fixing portion 41 of the spring 40 covered with the synthetic resin 42 is elastically deformed by the urging force of the spring 40. Therefore, the contact area between the magnet 20 and the spring 40 increases. As a result, the magnet 20 can be securely fixed.

The present embodiment can be embodied with the following modifications. -The part of the magnet 20 which contacts the spring 40 may be covered with the synthetic resin 42.

The entire spring 40 may be covered with a synthetic resin 42 having relatively soft elasticity and heat resistance. A configuration may be adopted in which a synthetic resin 42 having relatively soft elasticity and heat resistance is interposed between the magnet 20 and the spring 40.

As shown in FIG. 3, the above-described embodiment may be applied to a spring in which a fixing portion 41 of a U-shaped spring 40 is formed by bending. In addition, the above embodiment may be applied to a structure in which the pair of magnets 20 is held by a leaf spring 50 shown in FIG. That is, the side surface 51 of the leaf spring 50 may be covered with the synthetic resin 42. Even with such a configuration, it is possible to obtain the same effect as the above-described embodiment.

Further, technical ideas other than the claims grasped from the above embodiment will be described below together with their effects. [1] In the magnet holding structure for a motor according to any one of claims 1 to 4, the urging means may be a U-shaped magnet.
A magnet holding structure for a motor, which is a spring formed in the shape of a letter.

With this configuration, the magnet can be securely held with a simple configuration. [2] The magnet holding structure for a motor according to any one of claims 1 to 4, wherein the urging means is a leaf spring.

Even with this configuration, the magnet can be securely held with a simple configuration.

[0021]

Since the present invention is configured as described above, it has the following effects. According to the invention described in any one of claims 1 to 4, damage to the magnet can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a relationship between a magnet and a spring.

FIG. 2 is a longitudinal sectional view taken along line AA of FIG.

FIG. 3 is a longitudinal sectional view taken along line AA of FIG. 1 showing another embodiment.

FIG. 4 is a perspective view showing a leaf spring according to another embodiment.

FIG. 5 is a perspective view showing a conventional relationship between a magnet and a spring.

[Explanation of symbols]

1 ... motor, 20 ... magnet, 21 ... central part, 40 ...
Spring as urging means, 42... Synthetic resin as buffer means.

Claims (4)

[Claims] 1. A magnet holding structure for a motor for holding a plurality of magnets on the inner peripheral surface of a cylindrical yoke, comprising: urging means for holding the magnets on the inner peripheral surface of the yoke; The magnet holding structure of the motor with buffer means interposed between the magnet and the magnet. 2. A magnet holding structure for a motor for holding a plurality of magnets on an inner peripheral surface of a cylindrical yoke, comprising: a biasing means for holding a magnet on an inner peripheral surface of a yoke; A magnet holding structure for a motor in which a portion of an urging means to be abutted is covered with a synthetic resin. 3. The magnet holding structure for a motor according to claim 2, wherein the synthetic resin is nylon or epoxy. 4. A magnet holding structure for a motor according to claim 1, wherein said urging means urges a central portion of the magnet.