Motor

Details Motor Motor

2002-03-07

2004-04-20

Ponomarenko, Nicholas (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Rotary

C310S090000

Reexamination Certificate

active

06724112

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a motor employing a ball bearing, more particularly relates it to a bearing structure of the motor, where unbalance load in a radial direction or thrust force in an axial direction is applied to the bearing.
BACKGROUND OF THE INVENTION
Recently, a motor of industrial-use is not only used for driving a conveyor and the like, but also used in variety of applications such as a robot or a pump, and the motors used in those machines work continuously for long hours. The market requires a ball bearing employed in those motors to have a longer service life because eccentric load in a radial direction or thrust force in an axial direction is applied to a motor shaft.
A motor with a ball bearing uses a wave washer in order to apply appropriate pre-load to the ball bearing, so that a longer service life of the ball bearing can be expected. A little space is provided between an outer ring of the ball bearing and a housing of the bearing to make the assembly a bit loose for pre-loading the ball bearing in the axial direction and for absorbing dimensional tolerance of the parts used in the motor.
A bearing structure of a conventional motor, which is employed for driving a conveyor, is described hereinafter with reference to FIG.
4
. In
FIG. 4
, rotor iron-core
17
is rigidly fit to motor shaft
16
, and stator iron-core
19
with coils is rigidly fit to frame
18
. Rear bracket
20
and front bracket
21
are mounted to an opening of frame
18
, and each of the brackets has a bearing housing at its center. Each of inner rings of rear ball bearing
22
and front ball bearing
23
is rigidly fit to motor shaft
16
, and an outer ring of rear ball bearing
22
is rigidly bonded to the bearing housing disposed at rear bracket
20
. An outer ring of front ball bearing
23
is not bonded. Wave washer
24
is inserted in front of bearing
23
, so that the ball bearing is pre-loaded by the spring pressure.
The structure discussed above, however, invites creep to the outer ring of the front ball bearing because the outer ring is simply left loose and pre-loaded by the wave washer. In particular, when unbalance load is applied in the radial direction, the outer ring becomes more subject to the creep, thereby reducing the service life of the bearing.
In the case of a servo-motor equipped with an optical encoder at its shaft, when the shaft moves in the axial direction against the pre-load by the wave washer, a rotary section and a stationary section of the encoder come into contact with each other, which may damage the encoder.
SUMMARY OF THE INVENTION
The present invention addresses the problems discussed above, and aims to provide a motor, of which ball bearing is prevented from creep at its outer ring, usable in variety of applications.
A motor of the present invention comprises the following elements:
a cup ring disposed before a front bracket; and
a holding plate disposed behind the front bracket.
The cup ring and the holding plate sandwich the front bracket, and the cup ring and the plate are screwed down to the front bracket so that the outer ring of the front ball bearing is tightly sandwiched and cannot move. As a result, this structure prevents the outer ring from incurring creep.


REFERENCES:
patent: 1635319 (1927-07-01), Grill
patent: 2345952 (1944-04-01), Smith
patent: 2819417 (1958-01-01), Glass
patent: 3447239 (1969-06-01), Slick
patent: 3944863 (1976-03-01), Apsit et al.
patent: 4629919 (1986-12-01), Merkle
patent: 5001377 (1991-03-01), Parkinson
patent: 6087746 (2000-07-01), Couvert et al.
patent: 6091173 (2000-07-01), Byrd
patent: 6297571 (2001-10-01), Knappenberger
patent: 3026835 (1982-02-01), None
patent: 3344249 (1985-04-01), None
patent: 19615889 (1997-10-01), None
patent: 0650058 (1995-04-01), None
European Search Report for EP 02 00 4392, dated Aug. 19, 2002.

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