JPH06169538A - Miniature motor - Google Patents

Abstract

PURPOSE:To provide a miniature motor which can secure the fastening strengths of its magnets without using any bonding agent and on the other hand can reduce its magnetic leakage. CONSTITUTION:Fastening parts 10, 10 are formed by raising-up inwards the wall-thickness parts of a motor case 1 in a cutting way. Magnets 2, 2 are inserted respectively into the motor case 1 in the directions of arrows, and the one-side-end parts thereof are contacted respectively with the fastening parts 10, 10. Further, a nearly C-shaped presser bar spring 3 is so squeezed in between the other-side-end parts of the magnets 2, 2 that side-end parts 30, 30 of the opening part of the nearly C-shaped spring 3 and an opposite side part 31 thereto are contacted respectively with the other-side-end parts of the magnets 2, 2. The presser bar spring 3 squeezed therein so presses the magnets 2, 2 on the fastening parts 10, 10 respectively that the side-end parts 30, 30 and the opposite side part 31 thereto expand in the opposite directions to each other respectively. Thereby, the two magnets 2, 2 are so supported respectively on the inner peripheral surface of the motor case 1 in a fastening way that they are opposed to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a small motor,
Specifically, it relates to fixing a magnet arranged in the motor case.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, a fixing means for a magnet of a small motor is configured such that a side end portion of a magnet 2 is brought into contact with a magnet stopper 10 formed by cutting and raising a part of a motor case 1 inward. The U-shaped magnet holding spring 3 which is inserted into the magnet 2 and abuts against the other side ends of the inserted magnet 2 that are not in contact with the magnet stopper 10 and pushes the gap between them.
The magnet 2 is fixed by press-fitting A between both end portions so that the substantially U-shaped opening is on the insertion direction side. Alternatively, there is a method of directly fixing the magnet to the inner peripheral surface of the motor case with an adhesive without using the pressing spring 3A of the magnet.

[0003]

In the conventional press-fitting spring fixing method using the U-shaped presser spring 3A of the prior art, since it can be press-fitted and fixed, automatic assembly is possible. On the other hand, the spring constant cannot be made very high,
Since the presser spring 3A is substantially U-shaped, the pressing spring constant is not stable, and the point where the presser spring 3A comes into contact is one point at the tip. There was a problem that the magnet came off and the magnet cracked. Further, the latter fixing method using an adhesive has a problem that it takes time to solidify the adhesive and it is difficult to perform automatic assembly.

On the other hand, in the former method of fixing the press-fitting spring, since there is a hole after the cut and raised magnet stopper 10 is cut and raised, the cross-sectional area of the plate thickness portion of the motor case is reduced, and the effective magnetic flux of the magnet is reduced. Would result in a so-called magnetic leakage phenomenon, resulting in a decrease in motor starting torque and an increase in current.

The present invention has been made in view of the above points, and a small motor which can secure the fixing strength of a magnet without using an adhesive and can reduce magnetic leakage on the other hand. It is provided.

[0006]

According to a first aspect of the present invention, there is provided a compact motor in which two magnets are arranged on an inner peripheral surface of a motor case so as to face each other, and the two magnets contact one end of each of the magnets. An engaging portion that contacts is formed on the wall surface of the case, and a holding spring body that presses both magnets in the engaging portion direction is arranged between the opposite ends of both magnets.
The pressing spring body is formed in a substantially C-shape, and the substantially C-shaped opening is arranged so as to abut the side end surface of the magnet.

In the small motor according to the second aspect, two magnets are arranged on the inner peripheral surface of the motor case so as to face each other, and a pressing spring body portion disposed between both end portions of both magnets facing each other is provided. It is characterized in that it is formed in a substantially U-shape, and at least one end of both substantially U-shaped openings of the pressing spring body is connected.

[0008]

According to the structure of the small motor as described above, since the substantially C-shaped opening of the pressing spring body is in contact with the side end surface of the magnet, the contact portion of the pressing spring body with the magnet is increased. The holding force increases and the magnet does not easily come off even when shocked, and, on the other hand, the approximately U-shaped magnet is fixed and held only by the pressing spring body, so there is no opening for fixing the magnet in the motor case, and the magnetic flux There is no decrease.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is an exploded perspective view of an essential part of a small-sized motor according to the present invention, in which 1 is a motor case, 2 is a magnet, 3 is a holding spring body, and 10 is a locking portion.

In this small motor, locking portions 10 and 10 are formed by cutting and raising the wall surface of the motor case 1 inward. Two magnets 2 and 2 are inserted into the motor case 1 in the direction of the arrows in the locking portions 10 and 10 so that one side ends of the magnets 2 and 2 come into contact with each other. The pressing spring body 3 is formed in a substantially C-shape, and the substantially C-shaped opening side end portions 30 and 30 and the opposite side portion 31 are the other side end portions of the magnets 2 and 2. It is press-fitted between the side end portions of the inserted magnets 2, 2 so as to abut. The press-fitting spring body 3 is press-fitted,
The substantially C-shaped opening side end portions 30, 30 and the opposite side portion 31
And magnets 2 and 2 are pressed toward the locking portion 10 so as to spread, and the two magnets 2 and 2 are arranged and fixed and held on the inner peripheral surface of the motor case 1 so as to face each other. Is.

FIG. 2 shows a state in which the assembled motor case stator shown in FIG. 1 is used in a small-sized motor M.
A rotor having a coil 12 wound around it is arranged to receive the magnetic flux of a magnet. As shown in FIG. 2B, the pressing spring body 3 is press-fitted between the magnets 2 and 2. In the figure, 4 is a brush section.

FIG. 3 shows an embodiment of the small motor according to the present invention. The pressing spring body 3a is connected to the pressing spring body portions 3c and 3c each having a substantially U shape by connecting one end portion of an opening of the pressing spring body portion 3c so as to be curved along the inner peripheral surface of the motor case 1 and the other end. Curved end portions 3d and 3d formed by being curved along the inner peripheral surface of the motor case 1 from the end portions of
Has been extended. This pressing spring body 3a is mounted in the motor case 1, and the magnets 2 and 2 are attached to both pressing spring body portions 3
The two magnets 2 and 2 are arranged so as to oppose each other on the inner peripheral surface of the motor case 1 by press-fitting so that the side end surfaces abut between c and 3c. As shown in FIG. 4A, the connecting portion 3b and the curved end portions 3d and 3d of the pressing spring body 3a are arranged and positioned at the bottom of the bottomed motor case 1, and have a substantially U-shape. The pressing spring body portions 3c and 3c will surely contact the side end portions of the magnets 2 and 2.

[0014]

Since the small motor of the present invention is constructed as described above, it is formed in a substantially C-shape and both ends of the opening abut on the side ends of the magnet, thus stabilizing the spring constant. It is possible to obtain sufficient holding strength with the pressing spring body,
The number of parts to be pressed into contact is increased and the magnet does not come off due to impact, etc., and it is possible to prevent the magnet from cracking.At the time of automatic assembly, it can be pressed in without checking the vertical direction of the presser spring body. Since the pressing spring body portion having a substantially U shape is connected,
The presser spring can be integrated to stabilize the spring constant, and the number of parts that come into pressure contact with the magnet increases, so the presser spring can provide sufficient holding strength, and the magnet will not come off due to impact, etc., and the magnet can be prevented from cracking. Since both ends of the magnet are fixed with springs, the cut-and-raised locking parts provided in the motor case are not required, and the reduction of magnetic flux due to magnetic leakage can be prevented, improving the starting torque and increasing the current. It can be prevented. Further, since no adhesive is used, automation is easy.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of essential parts of an embodiment of the present invention.

2 shows a small motor of the embodiment of FIG.
(A) is a longitudinal sectional view and (b) is an AA sectional view.

FIG. 3 is an exploded perspective view of essential parts of another embodiment of the present invention.

FIG. 4 shows a small motor of the embodiment of FIG.
(A) is a longitudinal sectional view and (b) is a BB sectional view.

FIG. 5 is an exploded perspective view of a main part of a conventional example.

[Explanation of symbols]

 1 Motor Case 2 Magnet 3 Presser Spring Body 3a Presser Spring Body 3b Connection Part 3c Presser Spring Body Part 3d Curved End

Claims (2)

[Claims] 1. An inner peripheral surface of a motor case is provided with two magnets so as to be opposed to each other, and a locking portion is formed on a wall surface of the motor case so as to abut against both opposite ends of one of the magnets. In a small motor in which a pressing spring body that presses a magnet in the direction of the locking portion is disposed between opposite ends of both magnets, the pressing spring body is formed in a substantially C-shape, and the substantially C-shape is formed. A small motor characterized in that the opening is arranged so as to contact the side end surface of the magnet. 2. A motor case is provided with two magnets on an inner peripheral surface thereof so as to face each other, and a pressing spring body portion disposed between both end portions of both magnets facing each other is formed in a substantially U shape. A small motor, characterized in that at least one end of both substantially U-shaped openings of the pressing spring body is connected.