JPS6011747Y2 - coreless motor - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a coreless motor.

The applicant for this utility model registration proposed a coreless motor as shown in Figure 1, and filed a patent application (Japanese Patent Application No. 49-98676) dated August 27, 1920.

That is, FIG. 1 is a longitudinal sectional view of the aforementioned coreless motor, in which a cup-shaped yoke 1 is formed by drawing or the like, an opening 1b is formed in the center of the bottom 1a, and the cup-shaped yoke 1 and the cylindrical shape are formed. The magnet 2 and the bearing 3at3b are made of synthetic resin 4.
They are simultaneously molded and integrated.

A cutaway perspective view of the stator S formed in this way is shown in the second figure.
As shown in the figure.

Next, the rotor R, in which the commutator segments 6.7 are provided on the substrate 5, and the shaft 8 and the cylindrical coil 9 are provided, is inserted into the stator S as shown.

At this time, the shaft 8 is rotatably supported by the bearings 3a and 3b, and a gap g is formed between the inner circumference of the cup-shaped yoke 1 and the outer circumference of the cylindrical coil 9.

Next, a cover body 13 with a brush 10 and terminals 11 and 12 is installed.
is mounted on the cup-shaped yoke 1, and the commutator segment 6.7
The brush 10 is brought into contact with.

In the coreless motor configured in this way, the cup-shaped yoke 1 is made into a cup shape by drawing or the like, and the cylindrical magnet 1 is
The gap g between the cup-shaped yoke 1 and the cylindrical magnet 2 is determined by the accuracy of the molding die, making it easy to achieve gap accuracy, and the assembly process is only a simultaneous molding process. This reduces the number of man-hours and parts, resulting in lower costs.

By the way, the cylindrical magnet 2 of the coreless motor having such a configuration is made of a radially anisotropic ferrite magnet, and since the amount of shrinkage after firing differs depending on the direction, cracks may occur. many.

If there is a crack in the cylindrical magnet 2, the crack may grow or break due to resin pressure when the cup-shaped yoke 1 and the cylindrical magnet 2 are simultaneously molded with resin, resulting in a high defect rate.

Furthermore, if a temperature cycle or impact is applied after assembly, the cylindrical magnet 2 may crack and hit the rotating cylindrical coil 9.

Therefore, an object of this invention is to provide a coreless motor that has good assembly accuracy, requires fewer assembly steps, and can prevent damage to the cylindrical magnet.

FIG. 3 is a cutaway perspective view of essential parts of an embodiment of the coreless motor of this invention.

In this embodiment, when the cup-shaped yoke 1 and the cylindrical magnet 2 are simultaneously molded with the synthetic resin 4, the synthetic resin 4 also covers the upper end surface of the ferrite cylindrical magnet 2, and the flange portion 4a
form.

That is, the synthetic resin 4 includes a holding cylinder part 14 that penetrates the center of the magnet 2 and holds the bearings 3a and 3b at both ends, flange parts 4a and 4b that support both end surfaces of the magnet 2, and the magnet 2. A fixing member including a connecting portion 15 connected to the opening 1b of the stator yoke 1 is configured.

Therefore, the synthetic resin 4 and its flange portion 4a are
It has both the function of positioning and holding the cup-shaped yoke 1 and the cylindrical magnet 2, and the function of preventing damage to the ferrite-made cylindrical magnet 2.

Further, after molding, the cylindrical magnet 2 is held down by the synthetic resin 4 from the top and bottom surfaces, so that the impact resistance is increased.

Furthermore, the contraction of the synthetic resin 4 after molding further strengthens the bond between the cylindrical magnet 2 and the cup-shaped yoke 1, which has the effect of preventing the cylindrical magnet 2 from swinging in the radial direction and from being pulled out.

Further, since the impact caused by the collision of the mold against the cylindrical magnet 2 during molding is reduced, chipping of the surface of the cylindrical magnet 2 is eliminated.

Incidentally, since the overall view of this coreless motor is the same as that shown in FIG. 1, illustration thereof is omitted.

As described above, the coreless motor of this invention includes a cup-shaped stator yoke with an opening at the bottom, a ferrite cylindrical magnet inserted into the center of the stator yoke, and a center portion of the magnet. a holding cylinder part that penetrates and holds the bearings at both ends; a flange part that supports both end surfaces of the magnet;
and a fixing member in which a connecting portion connecting the magnet to the opening of the stator yoke is integrally formed with resin by simultaneous molding, and a fixing member disposed between an inner periphery of the stator yoke and an outer periphery of the ferrite cylindrical magnet. By integrally forming the magnet and yoke with resin, the positional accuracy and gap accuracy of the magnet and stator yoke can be improved, and the center of the bearing and the center of the gap can be placed coaxially with high accuracy, making assembly easier. Less man-hours and lower costs,
In addition, the magnet is held in the radial and axial directions by the holding cylinder and flange, so it will not tilt or fall out due to vibration shock or temperature cycles, and the flange and holding cylinder surround the magnet. This has the effect of preventing the growth of cracks and damage to the magnet and reducing the product defect rate.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an example of a coreless motor that is the basis of this invention, Fig. 2 is a cutaway perspective view of its stator, and Fig. 3 is a cutaway perspective view of the main parts of an embodiment of the coreless motor of this invention. be. 1... Stator yoke, 2... Cylindrical magnet, 3a, 3b... Bearing, 4... Synthetic resin, 4a, 4b...・Flange part, 9...
...Cylindrical coil, 14...Holding cylinder part, 15...
・Connection part, R...Mountain-Yu.

Claims (1)

[Scope of utility model registration request] A cup-shaped stator yoke having an opening at the bottom, a ferrite cylindrical magnet inserted into the center of the stator yoke, and a holding cylindrical portion penetrating the center of the magnet and holding bearings at both ends; a fixing member in which a flange portion supporting both end surfaces of the magnet and a connecting portion connecting the magnet to the opening of the stator yoke are integrally formed by simultaneous molding of resin, an inner periphery of the stator yoke and the ferrite cylinder; A coreless motor equipped with a rotor coil arranged between the outer periphery of a shaped magnet.