JPH0549203A - Miniature motor - Google Patents

Abstract

PURPOSE:To obtain a miniature motor, high in the yield of material and capable of improving productivity, by a method wherein an oil dispersion preventing washer is formed of plastics material so as to be a disc type while both end faces thereof are provided with concentrical grooves at asymmetrical positions respectively. CONSTITUTION:An oil dispersion preventing washer is provided with grooves 14a, 14b concentrically on both end faces thereof while the groove 14a of one end face is provided at the asymmetrical position of the groove 14b at the other end face. In this case, projections 15a, 15b and the grooves 14a, 14b, which are formed on both of the end faces, are formed so as to be opposed to each other and, therefore, it is effective that a sheet, consisting of a thermoplastic resin material and rolled so as to have the shape of a hoop, is pressed through a sequentially sending mold. In this case, elongations in directions along the surfaces of the sheet are balanced since the grooves 14a, 14b provided on both end faces are positioned asymmetrically whereby bending of a formed form can be avoided and internal resistance upon forming can be reduced. As a result, the product is pressed and punched from the sheet material and, therefore, the yield of the material is improved remarkably, the productivity of the same is also improved and a manufacturing cost can remarkably be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small motor used in, for example, audio equipment and precision equipment, and more particularly to a small motor having an improved oil splash prevention washer provided between a commutator and a bearing. It is a thing.

[0002]

2. Description of the Related Art FIG. 3 is a vertical cross-sectional view of a main part showing an example of a small motor provided with an oil splattering washer which is an object of the present invention. In FIG. 3, reference numeral 1 denotes a housing, which is formed of a metal material such as soft iron into a hollow cylindrical shape having a bottom, and has an inner peripheral surface to which a permanent magnet 2 formed in, for example, an arc segment shape is fixed. A rotor 5 composed of an armature 3 facing the permanent magnet 2 and a commutator 4 can be disposed in the housing 1. Next, 6 is an end plate,
It is made of an insulating material and is fitted into the opening of the housing 1.

Reference numeral 7 is a brush, the free end of which is the commutator 4
It is provided so as to be slidably engaged with and is provided on the end plate 6 together with the terminal 8 electrically connected to the brush 7. Reference numerals 9 and 10 denote bearings, which are fixed to the bottom portion of the housing 1 and the central portion of the end plate 6, respectively.
The shafts 11 and 12 constituting the above are rotatably supported. Then 1
3 is an oil splash prevention washer, which is provided between the commutator 4 and the bearing 10 so as to rotate integrally with the shaft 12.

With the above structure, current is supplied to the armature 3 from the terminal 8 via the brush 7 and the commutator 4 forming the rotor 5, so that it is fixed to the inner peripheral surface of the housing 1. The rotating force is applied to the armature 3 existing in the magnetic field formed by the permanent magnets 2, and the rotor 5
Can be rotated, and an external device (not shown) can be driven through the output side shaft 11. In this case, since the oil scattering prevention washer 13 is provided between the commutator 4 and the bearing 10, the lubricating oil flowing out from the bearing 10 is prevented from flowing into the outer periphery of the commutator 4, and the brush 7 and the commutator 4 are prevented. It is possible to ensure electrical continuity between the two and to prevent a short circuit accident due to abnormal wear in the slit (not shown) of the commutator 4.

A number of proposals have been made for the oil splash prevention washer 13 described above. For example, a disk-shaped flange portion is integrally provided on the outer periphery of a hollow cylindrical cylindrical portion. There are a number of concentric V-shaped grooves engraved on both the front and back sides (see Japanese Utility Model Publication No. 51-44094). There is also a disc-shaped oil draining member integrally formed with a narrow band groove on the surface facing the bearing (Actual Kaisho)
52-108516). All of these items store the oil scattered from the bearings in the premises, so that the commutator 4
(See FIG. 3) can be prevented.

[0006]

Since the oil splash prevention washers 13 in the conventional small-sized motors described above are made of injection molding means using materials such as polyacetal, the material yield is low and the cost is low. There is a problem that it is high. That is, the injection mold is
Since it is necessary to form it with high precision and strength so that it can withstand high-pressure injection pressure, the cost inevitably increases and
Injection molding machines are also expensive.

Further, in this injection molding, a thermoplastic resin is heated in a heating cylinder to be fluidized, and this is pushed by a plunger into a mold by an injection ram. Therefore, a sprue or a runner for obtaining a molded product is obtained. , There are many surplus parts such as gates, resulting in a low material yield. Further, after the resin material is injected into the mold, the plunger cannot be retracted until the resin material is solidified, so that the number of shots per unit time is limited and the production speed is low.
Therefore, there is a problem that the manufacturing cost per molded product increases.

An object of the present invention is to solve the above problems existing in the prior art, and to provide a small motor having a high material yield and an improved oil splattering washer so as to improve the productivity. And

[0009]

In order to achieve the above object, according to the present invention, a housing formed in a hollow cylindrical shape with a bottom and having a permanent magnet fixed to the inner peripheral surface thereof, an armature and a commutator. An end plate having a rotor fitted with an opening of the housing and a brush slidably contacting the commutator and a terminal electrically connected to the brush. The rotor is rotatably supported via bearings provided on the housing and the end plate, and an oil splash prevention washer is provided between the commutator and the bearing of the end plate so as to rotate integrally with the rotor. For small motors, the technical measure is to form the oil splash prevention washers in the shape of a disk with a plastic material and to provide concentric grooves on both end surfaces at non-corresponding positions. It was.

[0010]

With the above construction, the yield of the oil splattering washer can be greatly improved and the productivity can also be greatly improved.

[0011]

1 is an end view showing an example of an oil splash prevention washer according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line A--A in FIG. In FIGS. 1 and 2, 14a and 14b
Is a groove and is provided concentrically on both end surfaces of the oil splash prevention washer 13, and a groove 14a on one end surface and a groove 14b on the other end surface are provided in non-corresponding positions. That is, the convex portions 15a and 15b formed on both end surfaces and the grooves 14b and 14a are formed so as to correspond to each other.

In order to form the above oil scattering washer 13, it is effective to use a sheet made of a thermoplastic resin material wound in a hoop shape and press the sheet through a progressive die. In this case, if the groove 14a or 14b shown in FIGS. 1 and 2 is provided only on one end surface, the molded product will be curved due to the elongation in the direction along the sheet surface during molding, but in the present embodiment, Since the grooves 14a and 14b provided on both end surfaces are in the non-corresponding positions, the expansion in the direction along the surface of the sheet is balanced and the bending of the molded product can be avoided. Further, since the grooves 14a and 14b are provided at the non-corresponding positions, the internal resistance at the time of molding is reduced.

In the present embodiment, the groove 1 provided on both end surfaces
The case where each of 4a and 14b is one has been described,
It may be a plurality of two or more. Also, the grooves 14a, 14b
It is needless to say that the cross-sectional shape of is not limited to a rectangular shape, but may be a triangular shape, a semicircular shape, or any other shape.

[0014]

The present invention has the following effects because it has the structure and operation as described above. (1) Since a sheet-shaped thermoplastic resin material can be press-forward-processed to form an oil splattering washer, the die cost can be significantly reduced compared to the conventional injection molding means, and the production equipment cost can be reduced. Can also be significantly reduced.

(2) Since the sheet-shaped material is processed and punched, the material yield is significantly improved and the surplus material is significantly reduced. (3) The productivity is significantly improved as compared with the conventional injection molded product.

(4) As a result of the above, the manufacturing cost of the oil scattering prevention washer is significantly reduced.

[Brief description of drawings]

FIG. 1 is an end view showing an example of an oil splash prevention washer in an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a longitudinal sectional view of an essential part showing an example of a small-sized motor provided with an oil splash prevention washer which is an object of the present invention.

[Explanation of symbols]

 13 Oil splash prevention washers 14a, 14b Grooves

Claims (1)

[Claims] 1. A housing formed into a hollow cylinder having a bottom and having a permanent magnet fixed to an inner peripheral surface thereof, a rotor including an armature and a commutator, and a housing fitted into an opening of the housing. The end plate is provided with a brush slidably contacting the commutator and a terminal electrically connected to the brush, and the rotor is mounted on the housing and a bearing provided on the end plate. In a small motor that is rotatably supported and has an oil splash prevention washer that rotates integrally with the rotor between the commutator and the bearing of the end plate. A small motor characterized by being formed and having concentric grooves on both ends thereof at non-corresponding positions.