JPH0568354A - Small electric motor - Google Patents

Abstract

(57) [Summary] [Structure] A rubber seal member having a bearing oil seal and a bearing oil splash prevention structure is press-fitted onto the rotating shaft. Further, the rubber seal member has a stepped portion in the radial direction of the rubber seal member so as not to form an oil reservoir between the rotary shaft and the rubber seal member. Further, an oil stopper and a rubber seal member retaining groove are formed on the rotary shaft. [Effect] The bearing oil splattering preventive unit can be constructed only by assembling the rubber seal member, and the processing man-hours and the component cost are about 1/2 or less as compared with those which are composed of two or more components.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small electric motor, and more particularly to a small electric motor having a bearing oil seal structure which is highly reliable and economical.

[0002]

2. Description of the Related Art As described in Japanese Utility Model Laid-Open No. 62-98459, a structure for preventing the bearing oil of a small electric motor from flowing out to the commutator surface is provided between the lower end surface of the oil-impregnated bearing and the peripheral portion of the insertion hole of the end bracket. An oil seal member, and an oil stop groove formed between the lower end surface of the oil-impregnated bearing and the commutator is formed,
The commutator is provided with a recess facing the lower end surface of the oil-impregnated bearing, and the oil residue member is installed in the recess.

[0003]

However, the above-mentioned prior art lacks consideration for the temperature rise of the bearing because the surroundings of the bearing are close to a closed state. Further, the oil seal member and the oil adsorbing member constitute a bearing oil splash prevention portion. However, the oil adsorbing member is left on the wall of the mold and the bearing oil that has permeated into the oil adsorbing material is subjected to centrifugal force. It lacks consideration for the swelling of the commi-mold material due to clogging of the comi-bar surface, clogging of the comi-bar, and penetration of the comi-mold. Further, since the bearing oil splash prevention section is composed of two members, the productivity and the cost of parts are relatively high.

The present invention aims to overcome these problems.

[0005]

In order to achieve the above object, according to the present invention, a commutator is arranged in the rotor in the vicinity of the oil-impregnated bearing or in the vertical posture downstream of the oil-impregnated bearing. In the small electric motor having the above, a bearing oil seal and a rubber seal member having a bearing oil splash prevention structure are press-fitted to the rotary shaft. Further, the rubber seal member has a stepped portion in the radial direction of the rubber seal member so as not to form an oil reservoir between the rotary shaft and the rubber seal member. Further, an oil stopper and a rubber seal member retaining groove are formed on the rotary shaft.

[0006]

According to the construction of the present invention, the rubber seal member is press-fitted and fixed in the groove formed in the rotary shaft to seal the bearing oil outflow to the downstream side. A small ring-shaped projection smaller than the outer diameter of the rotary shaft is formed at the press-fitting portion of the rubber seal member to the rotary shaft, and more reliable sealing is ensured by press-fitting the entire circumference. In order to further improve the sealing property of the rubber seal member, a stepped portion is formed in the radial direction of the rubber seal member so that an oil pool is not formed between the rotary shaft and the rubber seal member for a long period of time. However, an oil reservoir is formed on the rubber seal member. Further, the oil accumulated in the rubber seal member tends to be scattered in the circumferential direction by the rotation, but a return is formed in the rubber seal member to prevent the scattering. As described above, the oil flowing out from the bearing is surely sealed by the rubber scraper, clogging between the commutator bars,
Problems such as swelling due to oil absorption of the comma mold material are eliminated.

Further, since the bearing oil scattering prevention structure is formed only by the rubber scraper, the number of parts can be reduced to reduce the number of processing steps and the cost of parts, which is advantageous for cost reduction.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3. FIG. 1 is a cross-sectional view of a small electric motor according to an embodiment of the present invention, in which a rotor 9 is disposed inside, a yoke 1 having an end bracket 4 attached to an upper end opening, and a yoke at the center of the end bracket 4. 1, an oil-impregnated bearing 5 mounted at a position coaxial with the oil-impregnated bearing 5, and an oil-impregnated member 6 arranged in contact with the outer peripheral surface of the oil-impregnated bearing 5 to replenish the oil-impregnated bearing 5 with oil; Has a commutator 7 arranged at a position close to or to the downstream side and a rotating shaft 3 constituting a rotor 9 supported by the oil-impregnated bearing 5, and the rotating shaft 3 has a bearing oil seal and a bearing oil splash. The rubber seal member 8 having the prevention structure is press-fitted and held. The oil entrance side entrance diameter of the rubber seal member is made larger than the bearing support portion outer diameter of the end bracket 4 which supports the oil-impregnated bearing 5, and FIG.
As shown in FIG. 4, the rubber seal member 8 forms a small annular ring-shaped projection having a diameter smaller than the groove outer diameter of the rotary shaft 3 on the press-fitted inner diameter surface side with the rotary shaft 3 to maintain airtightness during press fitting. . Further, the rubber seal member 8 is provided with a stepped portion 1 so as to form an oil sump portion.
1 is formed. Further, FIG. 3 shows a sectional view of a main part of the rubber seal member assembly. The rotating shaft 3 is provided with an oil stopper and a rubber seal member retaining groove.

[0009]

Since the present invention is constructed as described above, it brings about the following effects.

The bearing oil splattering preventive portion can be constructed only by assembling a rubber seal member, and the number of processing steps and the cost of the parts are about 1/2 or less as compared with the case where the number of parts is two or more. In addition, the seal structure can prevent the bearing oil from flowing out to the downstream side, can prevent the clogging due to the bearing oil outflow between the commutator bars, and the swelling deformation due to the absorption of the bearing oil in the commi-molded material. Problems such as sound generation can be prevented and reliability can be improved.

[Brief description of drawings]

FIG. 1 is a side vertical sectional view of an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a rubber sealing material.

FIG. 3 is a cross-sectional view of a main part of a rubber seal member assembly.

FIG. 4 is a vertical cross-sectional view of a rubber sealing material of another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Yoke, 2 ... Stator, 3 ... Rotating shaft, 4 ... End bracket, 5 ... Oil-impregnated bearing, 6 ... Oil-impregnated member, 7 ... Commutator, 8
... rubber seal member, 9 ... rotor, 10 ... small annular projection, 11 ... stepped portion, 12 ... return portion, 13 ... groove portion.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinori Fukasaku 2520 Takaba, Katsuta City, Ibaraki Prefecture Hitachi Ltd. Automotive Equipment Division

Claims (4)

[Claims] 1. A yoke in which a rotor is arranged and an end bracket is attached to an upper end opening, an oil-impregnated bearing which is attached to a center of the end bracket at a position coaxial with the yoke, and the oil-impregnated bearing of the oil-impregnated bearing. An oil-impregnated member arranged in contact with the outer peripheral surface to replenish the oil-impregnated bearing with oil, a commutator arranged in the rotor in a position close to the oil-impregnated bearing, and a rotor supported by the oil-impregnated bearing. A small-sized electric motor having a rotary shaft constituting the above, and a rubber seal member having both a bearing oil seal and a bearing oil splash prevention structure is press-fitted to the rotary shaft. 2. The small electric motor according to claim 1, wherein an oil stopper and a rubber seal member retaining groove are formed on the rotary shaft. 3. The rubber seal member is provided with a stepped portion in the radial direction of the rubber seal member so that an oil sump portion is not formed between the rotary shaft and the rubber seal member, and the stepped recess is formed by an oil step. The small electric motor according to claim 1, wherein the small electric motor forms a reservoir. 4. The small electric motor according to claim 1, wherein the rubber seal member is arranged on the upstream side in the axial direction when the small electric motor is used.