JP2000166163A - Dc brushless motor equipped with oil leakage preventive structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC brushless motor which is of simple structure, and from which lubricant never leaks. SOLUTION: A DC brushless motor, where rotors 5, 9, and 16 are fixed to the shaft 4 born by a bearing housing 2 and a turn table (6, 8) is attached to the output end of that shaft 4, is equipped with an oil leakage preventive structure consisting of plural coaxial grooves in the vicinity of the center of the non-medium placement face of the turn table (6, 8) or in the vicinity of the center of the inner side face of the rotor case.

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 oil leakage of a DC brushless motor.

[0002]

2. Description of the Related Art Conventionally, there has been a problem that lubricating oil in a bearing housing rises along a shaft due to rotation and vibration of a motor and a temperature rise accompanying the rotation, and scatters around due to rotation of a rotor. For this reason, a method of applying a fluorine-based solvent having an oil-repellent effect in the middle of the shaft has been proposed. This will be described below with reference to the drawings.

FIG. 3 is a cross-sectional view of a main part showing a state in which a means such as applying a fluorine-based solvent having an oil-repellent effect to the middle of a conventional shaft has been taken. In the figure, 1 is a base, 2 is a bearing housing implanted on the base 1, 3
Is a bearing inserted into the inner periphery of the bearing housing 2 by press fitting or the like. Reference numeral 4 denotes a shaft supported by the bearing 3, reference numeral 5 denotes a rotor case fixed to the shaft 4, reference numeral 6 denotes a turntable attached to an output end of the shaft 4, and reference numeral 7 denotes a center of the rotor case 5 from the shaft 4. It is a fluorine-based solvent applied near the part.

[0004]

In the DC brushless motor constructed as described above, the lubricating oil crawling on the shaft with the rotation of the motor can be prevented to some extent by the fluorine-based solvent, but is incomplete. Was. The lubricating oil that has reached the rotor case 5 once is
Despite the fact that the fluorine-based solvent is applied, there is a drawback that the solvent is blown outward by centrifugal force and transmitted along the inner wall of the rotor case 5 and leaks to the outside.

The present invention has been made to solve the above-mentioned drawbacks and to provide a DC brushless motor having a simple structure in which lubricating oil does not leak out of the motor.

[0006]

According to the first aspect of the present invention, a rotor is fixedly mounted on a shaft supported by a bearing housing, and a turntable is mounted on an output end of the shaft. This can be achieved by providing a DC brushless motor having an oil leakage prevention structure including a plurality of concentric grooves. According to the invention of claim 2, the oil leakage prevention structure including the plurality of concentric grooves includes:
This can be achieved by providing the turntable near the center of the non-medium mounting surface. According to the third aspect of the present invention, the oil leakage prevention structure including the plurality of concentric grooves can be achieved by being provided near the center of the inner surface of the rotor case.

With this configuration, the lubricating oil that crawls on the shaft with the rotation of the motor is prevented from leaking to the outside because the plurality of concentric grooves become the lubricating oil pool.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a main part showing a first embodiment of the present invention. In the figure, 1 is a base, 2 is a bearing housing implanted on the base 1, 3
Is a bearing inserted into the inner periphery of the bearing housing 2 by press fitting or the like. Reference numeral 4 denotes a shaft supported by the bearing 3, and reference numeral 8 denotes a turntable attached to the output end of the shaft 4. The turntable 8 has a first annular groove 14 near the center of the non-medium mounting surface. There is provided an oil leakage prevention structure including a second annular groove 15 provided concentrically with the first annular groove 14. Reference numeral 9 denotes an inverted cup type rotor case fixed to the annular projections on the outer periphery of the plurality of annular grooves of the turntable 8 by press fitting or the like, and 10 is fixed to the inner periphery of the inverted cup type rotor case 9 by press fitting or bonding or the like. Ring magnet. 11 is a bottom plate fitted to the bottom of the bearing housing 2 by screwing or press fitting, 12 is a thrust bearing for regulating the shaft 4 in the axial direction, and 13 is a stator fixedly provided on the outer periphery of the bearing housing 2. Coil.

In the DC brushless motor constructed as described above, the motor is driven, and the lubricating oil in the bearing housing rises along the shaft with the rotation of the rotor, and the surrounding oil is centrifugally generated by the rotation of the turntable 8. The first annular groove 14 and the second annular groove 15 do not scatter. In the first embodiment, two of the first annular groove 14 and the second annular groove 15
Although two annular grooves are provided, the number of annular grooves may be appropriately determined by a designer. In addition, if the outer peripheral side wall of the annular groove is formed in a U-shaped or U-shaped groove, the lubricating oil that has risen along the shaft is U-shaped or U-shaped due to centrifugal force caused by the rotation of the turntable 8. Is securely held in the groove, and there is no danger of further scattering around.

FIG. 2 is a sectional view of a main part showing a second embodiment of the present invention. In the figure, reference numeral 16 denotes an inverted cup type rotor case, which is provided near a center portion of a surface (inner side surface) on the bearing housing side, and is provided concentrically with the first annular groove 17. An oil leakage prevention structure including the second annular groove 18 is provided.

In the DC brushless motor constructed as described above, even if the lubricating oil in the bearing housing rises along the shaft with the rotation of the rotor and tries to scatter around by the centrifugal force, the first embodiment is applied. As in the case of the embodiment, the first annular groove 17 and the second annular groove 18 hold and do not scatter. In this case as well, if the outer peripheral side wall of the annular groove is formed in a U-shaped or U-shaped groove, the lubricating oil that has risen along the shaft will be U-shaped or U-shaped due to the centrifugal force accompanying the rotation of the rotor case 16. It is securely held in the U-shaped groove, and there is no danger of further scattering around.

[0012]

As described above, according to the present invention, by providing a plurality of concentric circular grooves on the turntable 8 or the rotor case 16, the circular grooves serve as lubricating oil reservoirs and can be lubricated with a simple structure. It is possible to provide a DC brushless motor in which oil does not leak out of the motor.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a DC brushless motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a main part of a DC brushless motor according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a main part of a conventional DC brushless motor.

[Explanation of symbols]

 Reference Signs List 1 base 2 bearing housing 3 bearing 4 shaft 5, 9, 16 rotor case 6, 8 turntable 10 ring magnet 14, 17 first annular groove 15, 18 second annular groove

Claims (3)

[Claims] 1. A direct current brushless motor in which a rotor is fixed to a shaft supported by a bearing housing and a turntable is attached to an output end of the shaft, wherein an oil leakage prevention structure including a plurality of concentric grooves is provided. DC brushless motor characterized by the following. 2. The DC brushless motor according to claim 1, wherein the oil leakage prevention structure including the plurality of concentric grooves is provided near a center of the non-medium mounting surface of the turntable. 3. The DC brushless motor according to claim 1, wherein the oil leakage prevention structure including the plurality of concentric grooves is provided near the center of the inner surface of the rotor case.