JPH10271787A - Structure for preventing rattling noise of miniature motor in thrust direction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mass-producible structure for preventing rattling noise of a miniature motor in the thrust direction without increasing the weight or the size of the motor itself. SOLUTION: Rattling noise is prevented in the thrust direction for a miniature motor M comprising a rotor 6 having a winding 5 and a stator having at least a set of field permanent magnets 1. Each of the at least a set of field permanent magnets 1 comprises a first permanent magnet 1a and a second permanent magnet 1b stronger than the first permanent magnet 1a. The second permanent magnet 1b is arranged contiguously to the first permanent magnet 1 in the axial direction and the second permanent magnets 1b are formed in the same direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for preventing abnormal noise in a small motor, and more particularly to a structure for preventing noise in a small motor for use in a thrust direction in a small motor for in-vehicle use. .

[0002]

2. Description of the Related Art A rotor or the like may play in the thrust direction in a motor due to external vibrations or the like, which may cause abnormal noise. In order to eliminate the generation of the abnormal noise, the height center 11a of the permanent magnet 11 disposed on the motor M1 and the height center 13a of the core 13 are shifted as shown in FIG. There is a technique in which a thrust in the small motor M1 in the thrust direction is eliminated by generating a magnetic force in B to hold down the armature, that is, by a so-called magnetic force, so as to eliminate noise caused by the play.

[0003] Alternatively, as disclosed in Japanese Utility Model Laid-Open Publication No. 5-48574, a weak magnet having a relatively weak magnetic force and a strong magnet having a relatively strong magnetic force are provided as permanent magnets. The weak magnet and the strong magnet are arranged adjacent to each other in the direction of the rotation axis of the motor, and the other opposing magnetic poles are arranged adjacent to each other in the reverse order to the above arrangement order. There has been proposed a technique for suppressing noise generated between a rotating shaft and a bearing by being attracted.

[0004]

However, FIG.
Small motor M1 requiring preload by magnetic force indicated by
In order to obtain the same output as that of the small motor M2 having the same shape and not requiring the preload by the magnetic force shown in FIG. 4B, in order to secure the amount of magnetic flux of the permanent magnet required for rotation of the motor, Permanent magnet 11 disposed on small motor M2
It is necessary to dispose a larger permanent magnet 11 than that, which causes a problem that the weight of the motor itself increases and the physical size in the thrust direction also increases.

Further, the motor M1 which requires preloading by magnetic force shown in FIG. 4 (a) and the motor M2 which does not need preloading by magnetic force shown in FIG. However, since the sizes of the permanent magnets 11 are different, it is necessary to create a plurality of types of mounting jigs for the permanent magnets 11 in the mounting process,
When the permanent magnet mounting position is changed, it is necessary to temporarily stop the operation of the equipment. As a result, the automation line becomes expensive, the efficiency in mass production decreases,
There was a problem that the manufacturing cost was high.

The technique disclosed in Japanese Utility Model Laid-Open No. 5-48574 is a technique for preventing abnormal noise generated between a rotating shaft and a bearing, and is a subject of the present invention. It is not possible to cope with abnormal noise generated due to backlash in the thrust direction due to external force.

SUMMARY OF THE INVENTION It is an object of the present invention to prevent abnormal noise caused by rattling in a thrust direction in a small motor without increasing the weight and size of the motor itself, and in the thrust direction of a small motor capable of mass production. An object of the present invention is to provide a rattling noise prevention structure.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a structure for preventing rattle noise in a thrust direction in a small motor, comprising a rotor having a winding and a stator having at least one set of field permanent magnets. In the motor, each of the at least one pair of field permanent magnets is configured such that a first permanent magnet and a second permanent magnet having a stronger magnetic force than the first permanent magnet are axially adjacent to each other, Each of the second permanent magnets is formed at a position in the same direction.

It is preferable that the second permanent magnet is provided so as to be located on the side opposite to the output shaft of the small motor.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure for preventing rattle noise in the thrust direction of a small motor M according to the present invention comprises a rotor 6 having a winding 5,
And a stator having a set of field permanent magnets 1. Each set of field permanent magnets 1 is a first permanent magnet 1
a and a second permanent magnet 1b having a stronger magnetic force than the first permanent magnet 1a are arranged adjacent to each other in the axial direction.
Each second permanent magnet 1b is formed at the same direction position.

With the above configuration, a magnetic force is generated in the thrust direction of the rotating shaft 4 constituting the rotor 6, and the rotor 6 is held down and held in a certain direction by the magnetic force. In this way, it is possible to prevent the small motor M from rattling in the thrust direction, and it is possible to prevent abnormal noise caused by the rattling.

[0012]

An embodiment of the present invention will be described below with reference to the drawings. The members, arrangements, and the like described below do not limit the present invention, and can be variously modified within the scope of the present invention.

FIGS. 1 and 2 show a specific embodiment of the present invention. FIG. 1 is an explanatory sectional view of a small motor having a thrust direction rattle preventing structure of this embodiment, and FIG. 2 is a permanent magnet. FIG.

The small motor M according to the present embodiment includes a permanent magnet 1, a housing 2, a core 3, and a rotating shaft 4 as main components.

The housing 2 of this embodiment is formed in a hollow cylindrical body, and a rotor 6 is disposed inside the housing 2. The rotor 6 includes the core 3, the rotating shaft 4, the winding 5
And is composed of

Further, a permanent magnet 1 for a magnetic field is disposed on the inner side wall of the housing 2 to constitute a stator.
As shown in FIGS. 1 and 2, the permanent magnet 1 of the present embodiment includes a first permanent magnet 1 a formed of a normal material and the first permanent magnet 1 a.
Second permanent magnet 1 having a higher magnetic flux density than the permanent magnet 1a of FIG.
b, and are arranged adjacent to each other as shown in FIG. In this example, the first permanent magnet 1a
And the second permanent magnet 1b are formed in the same size.

The permanent magnet 1 is previously provided with a first permanent magnet 1a.
And the second permanent magnet 1b may be integrally formed. Alternatively, the first permanent magnet 1a and the second permanent magnet 1b formed separately are arranged adjacent to each other by a method of bonding with an adhesive or a method of mechanically fixing the permanent magnet 1 to form the permanent magnet 1. You may.

Next, a structure for preventing the backlash noise in the small motor M using the permanent magnet 1 will be described. The small motor M is provided with a set of magnetic poles for creating a field, and the magnetic poles are formed by disposing the permanent magnet 1 in the housing 2.

As shown in FIG. 1, in each magnetic pole, the permanent magnet 1 is set so that the first permanent magnet 1a is on the right side of the drawing and the second permanent magnet 1b is on the left side of the drawing. Deploy. That is, the small motor M of the present example is configured such that the second permanent magnet 1b having a high magnetic flux density is located on the side opposite to the output shaft of the small motor M.

At this time, at each magnetic pole,
The center 1 c of the permanent magnet 1 is disposed in alignment with the center 7 of the core 3. The center 1c of the permanent magnet 1 is a position where the length of the permanent magnet 1 is bisected in the direction of the rotation axis 4. In this example, the first permanent magnet 1a and the second permanent magnet 1b are separated from each other. Since they are formed in the same size, the boundary between the first permanent magnet 1a and the second permanent magnet 1b is the center 1c of the permanent magnet 1.

By arranging the permanent magnet 1 as described above, a magnetic force in the thrust direction is generated in the direction of arrow A in FIG. 1, and the rotor 6 is drawn in the direction of arrow A by this magnetic force. Then, the rotor 6 and the rotary shaft 4 are pressed and held on the housing 2 on the side opposite to the output shaft.

With the above configuration, even when an external force such as vibration from the outside is transmitted to the small motor M, the rotor 6 does not rattle in the thrust direction, and noise generated due to rattling can be prevented.

The permanent magnet 1 used in the small motor M of the present embodiment is different from the permanent magnet used in the small motor which does not have a special structure for preventing abnormal noise as in the present embodiment. Therefore, since it can be configured without changing the size and arrangement position, in the same line as other small motors, multiple types of jigs can be created for mounting permanent magnets, Manufacturing can be performed without temporarily stopping the operation of the equipment due to a change in the mounting position, and efficient production can be achieved.

FIG. 3 is an explanatory diagram showing a second embodiment of the present invention. In the above-described embodiment, an example is shown in which the first permanent magnet 1a and the second permanent magnet 1b are formed to have the same size. However, in this example, the first permanent magnet 1a and the second permanent magnet 1a 1b is formed to have a different size. By adjusting the balance between the sizes of the two magnets as described above, it is also possible to adjust the force for attracting the rotor 6 and the rotating shaft 4 without changing the overall scale.

Also in this embodiment, as shown in FIG. 3, the permanent magnet 1 has the second permanent magnet 1b arranged in the same direction, the center 1c of the permanent magnet 1 and the center of the core 3. 7 are arranged so as to coincide with each other.

In the above embodiment, an example is shown in which the second permanent magnet 1b constituting the permanent magnet 1 in the magnetic pole is disposed on the side opposite to the output shaft. However, the present invention is not limited to this. 1b may be arranged on the output shaft side, and the rotor 6 may be held by being attracted to the output shaft side.

Although one set of permanent magnets 1 is used in this embodiment, a small motor having one or more sets, for example, two sets of permanent magnets can be applied.

[0028]

As described above, the small motor of the present invention
A first permanent magnet having a normal output, and a field permanent magnet composed of a second permanent magnet having a higher magnetic flux density than the first permanent magnet are provided. By generating a magnetic force, the rotor and the rotating shaft are attracted and held in a certain direction, so that even when an external force such as vibration from the outside is transmitted, the rotating shaft in the rotating shaft thrust direction can be used in a small motor. The occurrence of rattling can be prevented, and abnormal noise due to the rattling can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a small motor according to the present invention.

FIG. 2 is a perspective view of a field magnet according to the present invention.

FIG. 3 is an explanatory view showing another embodiment of the present invention.

FIGS. 4A and 4B are explanatory diagrams showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Permanent magnet 1a 1st permanent magnet 1b 2nd permanent magnet 1c Center of permanent magnet 2 Housing 3 Core 4 Rotation axis 5 Winding 6 Rotor 7 Center of core M Small motor

Claims (2)

[Claims] 1. A small motor comprising: a rotor having a winding; and a stator having at least one set of field permanent magnets, wherein each of the at least one set of field permanent magnets is a first permanent magnet. And a second permanent magnet having a stronger magnetic force than the first permanent magnet is arranged adjacent to the axial direction, and the second permanent magnets are formed in the same direction. Thrust direction rattle noise prevention structure for small motors. 2. The structure of claim 1, wherein the second permanent magnet is disposed so as to be located on a side opposite to the output shaft of the small motor.