JP3250273B2 - Thin cylindrical coreless motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin cylindrical coreless motor used for OA equipment or video equipment.

[0002]

2. Description of the Related Art In recent years, as small-sized cylindrical coreless motors have become smaller and thinner in OA equipment and video equipment, there has been a demand for small-sized, low-power-consumption and highly-reliable DC motors.

[0003] A conventional small DC motor will be described below. FIG. 4 shows a structural view of a conventional cylindrical coreless motor. Reference numeral 14 denotes a shaft, which takes out an output, and fixes three coil groups via 15 commutators to form a rotor. Reference numeral 9 denotes a bearing, which is press-fitted into a housing 10 and fixed to a frame 11 to rotatably support a rotor. Twelve cylindrical magnets are fixed to the housing 10 to form a magnetic circuit with the frame 11. A torque is generated by energizing the rotor through the brush assembly 13, and the torque is output through the shaft 14.

[0004]

However, in the above-described conventional configuration, the motor has been reduced in size, and high efficiency and high reliability have been demanded today. Insufficient thickness, insufficient lateral pressure resistance, and insufficient service life. In addition, the characteristics of the magnets are such that the magnets are too thin, resulting in insufficient torque, and the magnetic operating point is lowered to cause demagnetization in an environment.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a small, highly efficient and highly reliable thin cylindrical coreless motor.

In order to achieve this object, a thin cylindrical coreless motor according to the present invention comprises a rotor whose shaft does not pass through the inside of a cylindrical coil group, a cylindrical magnet located inside the cylindrical coil group, and a coil supporting the cylindrical magnet. Frame with the group sandwiched in the hollow and outside the cylindrical coil group
Is fixed to the frame at the section and sandwiches the shaft output section
Thin cylindrical coreless motor with bearings supported at two points
And a weight causing rotation unbalance at the output unit.
The weight is located between the two bearings
It is characterized by:

[0007]

With this configuration, the bearings can be arranged evenly with respect to the load at the time of output, and a sufficient space can be secured in the bearings, and the reliability in the side pressure resistance and the life can be secured.
In terms of characteristics, the magnetic characteristics can be improved by using a cylindrical magnet as compared to the conventional cylindrical magnet,
In particular, the problem of demagnetization of the magnet, which is a problem when the motor is downsized, is solved.

[0008]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a shaft as an output shaft, which is fixed to three coil groups via two commutators. Reference numeral 4 denotes a cylindrical magnet, which is arranged with a space inside the coil group 3. Reference numeral 5 denotes a frame which fixes the cylindrical magnet 4 so as to be arranged with a space inside the coil group 3 and forms a magnetic circuit with the cylindrical magnet 4. Reference numeral 6 denotes a bearing, which is fixed by a housing 7 so as to rotatably support the shaft 1 at two points sandwiching the output portion.

The operation of the thus constructed cylindrical coreless motor will be described with reference to FIG.

FIG. 2A is a sectional view of a frame assembly according to the present invention, and FIG. 2B is a sectional view of a conventional frame assembly. An extremely large magnet thickness Lm can be obtained by exposing the shaft structure and the bearing portion that do not penetrate the inside of the coil group to the outside of the magnet.

[0012]

(Equation 1)

As shown in (Equation 1), the magnet thickness L
When m increases, the operating point of the magnetic circuit increases, so that not only can the magnetic flux be improved, but also demagnetization due to a temperature change can be prevented. In addition, by forming the bearing portion at two points sandwiching the output portion, the load is equally applied to the two bearings, so that the burden on the side close to the output is not large as in the conventional case, and the bearing volume can be large. Reliability is improved.

As described above, according to this embodiment, the rotor whose shaft does not pass through the inside of the cylindrical coil group, the columnar magnet positioned inside the cylindrical coil group, the cylindrical group magnet are supported and the coil group is sandwiched in the air. Frame, and fixed to the frame outside the cylindrical coil group.
By providing a bearing which is supported at two points sandwiching the output portion of the motor, the bearing portion can be arranged evenly with respect to the load at the time of output, a sufficient space can be secured, and reliability in the lateral pressure resistance and life can be secured. In terms of characteristics as well, the use of a cylindrical magnet as compared to the conventional cylindrical magnet improves the magnetic characteristics, and can provide a thin cylindrical coreless motor that solves the problem of demagnetization of the magnet, which is a problem particularly when the motor is made thinner. .

(Embodiment 2) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

In FIG. 3, reference numeral 1 denotes a shaft which is fixed to three coil groups via two commutators. Reference numeral 4 denotes a cylindrical magnet, which is arranged with a space inside the coil group 3. Reference numeral 5 denotes a frame which fixes the cylindrical magnet 4 so as to be arranged with a space inside the coil group 3 and forms a magnetic circuit with the cylindrical magnet 4. Reference numeral 6 denotes a bearing, which is fixed by a housing 7 so as to rotatably support the shaft 1 at two points sandwiching the output portion. The above is the same as the configuration in FIG. The difference from the configuration of FIG. 1 is that eight unbalanced weights are fixed to the output unit. As described above, by incorporating components for generating output in the output unit, it is possible to generate force more compactly and efficiently. In the second embodiment, what is fixed to the output shaft is the unbalanced weight 8, but it goes without saying that it may be a gear or a pulley.

[0017]

As described above, according to the present invention, the rotor in which the shaft does not penetrate the inside of the cylindrical coil group, the cylindrical magnet positioned inside the cylindrical coil group, and the cylindrical magnet are supported and the coil group is sandwiched in the air. And a bearing fixed to the frame outside the cylindrical coil group and supporting the shaft at two points sandwiching the output portion, so that the bearing portion can be arranged evenly with respect to the load at the time of output. In addition, a sufficient space can be secured, and reliability can be secured in terms of lateral pressure resistance and life. In terms of characteristics, compared to the conventional cylindrical magnet, the use of a cylindrical magnet can improve the magnetic characteristics, and can realize a thin cylindrical coreless motor that solves the problem of demagnetization of the magnet, which is a problem especially when downsizing the motor. .

[Brief description of the drawings]

FIG. 1 is a structural diagram of a thin cylindrical coreless motor according to a first embodiment of the present invention.

FIG. 2A is a sectional view of a frame assembly according to the first embodiment of the present invention; FIG. 2B is a sectional view of a conventional frame assembly;

FIG. 3 is a structural diagram of a thin cylindrical coreless motor according to a second embodiment of the present invention.

FIG. 4 is a structural diagram of a conventional thin cylindrical coreless motor.

[Explanation of symbols]

 1,14 shaft 2,15 commutator 3 coil group 4 cylindrical magnet 5,11 frame 6,9 bearing 7,10 housing 8 unbalanced weight 12 cylindrical magnet 13 brush assembly

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-218352 (JP, A) JP-A-56-117569 (JP, A) JP-A-4-183240 (JP, A) 93086 (JP, U) Hikaru 4-108377 (JP, U) Jiko 44-14571 (JP, Y1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 23/58 H02K 15 / 16

Claims (2)

(57) [Claims] 1. A rotor in which a shaft does not pass through the inside of a cylindrical coil group, a cylindrical magnet positioned inside the cylindrical coil group, and a frame supporting the cylindrical magnet and arranged so as to sandwich the coil group in a hollow state, A thin cylindrical coreless motor having a bearing fixed to the frame outside the cylindrical coil group and supported at two points sandwiching a shaft output portion.
A way that causes rotational unbalance at the output unit
The weight is located between the two bearings.
And a thin cylindrical coreless motor. 2. The two-point bearing is located at the end of the frame.
Is fixed to the housing and the unbalanced weight is
2. The thin cylindrical core according to claim 1, wherein said core is provided inside said housing.
Motor.