Motor device

Details Motor device Motor device

2003-02-21

2004-10-05

Footland, Lenard A. (Department: 3682)

Bearings

Rotary bearing

Fluid bearing

C384S420000, C384S121000

Reexamination Certificate

active

06799891

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a motor device with an oil-impregnated bearing which can be used for a magnetic recording and reproducing apparatus and the like.
BACKGROUND OF THE INVENTION
A motor device with an oil-impregnated bearing has been used for a capstan motor of a video tape recorder and the like (see Japanese Unexamined Patent Application Laid-Open No. 8-163806).
FIG. 9
shows a conventional motor device.
Reference numeral
1
denotes a housing that holds an oil-impregnated bearing
2
and a thrust bearing plate
3
. Reference numeral
4
denotes a stator printed circuit board mounted to the housing
1
, to which an end
7
of a wire of a coil
6
wound around a stator core
5
is connected. Reference numeral
8
denotes a rotor plate that holds a main magnet
9
and that has a shaft
10
attached to its center, the shaft being inserted into and supported by the oil-impregnated bearing
2
. Reference numeral
11
denotes a stopper member pressed into the shaft
10
so as to prevent the shaft
10
from slipping out of the oil-impregnated bearing
2
. The stopper member
11
slides on the thrust bearing plate
3
.
The rotor plate
8
, including the stopper member
11
, is rotated to smoothly slide the shaft
10
and the oil-impregnated bearing
2
. At this time, as shown in
FIG. 10
, because of oil dripped between the shaft
10
and the oil-impregnated bearing
2
and a pumping phenomenon caused by the sliding of the oil-impregnated bearing
2
and the shaft
10
, oil
12
oozes out from the oil-impregnated bearing
2
to lubricate between the shaft
10
and the oil-impregnated bearing
2
. This allows the bearing to function favorably while being lubricated.
However, with the above conventional configuration, while the shaft
10
and the oil-impregnated bearing
2
are sliding smoothly, the oil
12
oozes out through the stopper member
11
as shown in FIG.
11
. As the stopper member
11
rotates at high speed as shown in
FIG. 12
, leaking oil
12
a
is scattered toward the surroundings owing to centrifugal force as showing FIG.
13
. The scattered oil
12
a
sticks to a magnetic recording tape (not shown) in a magnetic recording and reproducing apparatus. This hinders the tape from running stably.
Further, if a large amount of oil is dripped between the shaft
10
and the oil-impregnated bearing
2
, it may be scattered. On the other hand, the amount of oil is insufficient, the lifetime of the bearing is shortened. Accordingly, the amount of oil must be controlled. This currently affects operability during manufacturing.
Furthermore, when the oil
12
a
is scattered, the amount of oil
12
otherwise contained in the oil-impregnated bearing
2
decreases. This significantly shortens the lifetime of the bearing.
DISCLOSURE OF THE INVENTION
The present invention solves these conventional problems. It is an object of the present invention to provide a motor device that allows manufacturing operations to be favorably performed, that is reliable and has a long lifetime, and that has a bearing enabling a tape to run stably over a long time if a magnetic recording and reproducing apparatus employs this motor device.
To accomplish this object, a motor device according to the present invention comprises a housing that holds a bearing, a shaft inserted into and supported by the bearing, oil that lubricates between the shaft and the bearing, a thrust bearing plate pressed into and fixed to the housing, and a stopper member pressed into the shaft so as to prevent the shaft from slipping out of the bearing, the stopper member sliding on the thrust bearing plate. The motor device characterizes at least any one of the following points.
(1) A cylindrical side wall integrated with the housing is located at an end side of the housing that is closer to the thrust bearing plate so as to surround an outer periphery of the stopper member, and an end surface of the side wall is higher than a top surface of the outermost periphery of the stopper member.
(2) A groove is formed around the shaft in a surface of the stopper member which is opposite the thrust bearing plate.
With this configuration, while the shaft and the oil-impregnated bearing are sliding smoothly, oil is prevented from oozing out through the stopper member and then scattering. In other words, oil can be prevented from scattering, even if the amount of oil dripped between the shaft and the oil-impregnated bearing during manufacturing is not strictly controlled so that a slightly excessive amount of oil is dripped. Consequently, such a motor device can be realized that allows manufacturing operations to be favorably performed, that is reliable and has a long lifetime, and that has a bearing enabling a tape to run stably over a long time if a magnetic recording and reproducing apparatus employs this motor device.
A motor device according to the present invention comprises a housing that holds a bearing, a shaft inserted into and supported by the bearing, oil that lubricates between the shaft and the bearing, a thrust bearing plate pressed into and fixed to the housing, and a stopper member pressed into the shaft so as to prevent the shaft from slipping out of the bearing, the stopper member sliding on the thrust bearing plate. The motor device is characterized in that a cylindrical side wall integrated with the housing is located on an end side of the housing that is closer to the thrust bearing plate, so as to surround an outer periphery of the stopper member, and an end surface of the side wall is set to be higher than a top surface of the outermost periphery of the stopper member.
Further, a motor device according to the present invention comprises a housing that holds a bearing, a shaft inserted into and supported by the bearing, oil that lubricates between the shaft and the bearing, a thrust bearing plate pressed into and fixed to the housing, and a stopper member pressed into the shaft, the stopper member sliding on the thrust bearing plate. The motor device is characterized in that a groove is formed around the shaft in a surface of the stopper member opposite the thrust bearing plate.
Furthermore, the motor device according to the present invention is characterized in that a cylindrical side wall integrated with the housing is located on an end side of the housing that is closer to the thrust bearing plate, so as to surround an outer periphery of the stopper member, and an end surface of the side wall is set to be higher than a top surface of the outermost periphery of the stopper member, and in that a groove is formed around the shaft in a surface of the stopper member that is opposite the thrust bearing plate.
Moreover, the motor device according to the present invention is characterized in that a cylindrical side wall is provided on an end side of the housing that is closer to the thrust bearing plate, so as to surround an outer periphery of the stopper member, and an end surface of the side wall is set to be higher than a top surface of the outermost periphery of the stopper member.
Further, the motor device according to the present invention is characterized in that a cylindrical side wall is located on an end side of the housing that is closer to the thrust bearing plate, so as to surround an outer periphery of the stopper member, and an end surface of the side wall is set to be higher than a top surface of the outermost periphery of the stopper member, and in that a groove is formed around the shaft in a surface of the stopper member that is opposite the thrust bearing plate.
Furthermore, the motor device according to the present invention is characterized in that an oil repellent film is formed on the end surface of the side wall. Moreover, the motor device according to the present invention is characterized in that an oil repellent film is formed on the surface of the stopper member that is opposite the thrust bearing plate, at a position peripherally outward of the groove.


REFERENCES:
patent: 5112141 (1992-05-01), Asada et al.
patent: 5806987 (1998-09-01), Nose et al.

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