Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2001-01-26
2002-12-24
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S216055
Reexamination Certificate
active
06498412
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fixing structure for a rotor, and, more particularly, to a rotor of a brushless motor that can be detached and assembled easily.
2. Description of the Related Art
FIGS. 1 and 2
illustrate a conventional brushless motor comprising a casing
90
with an axle seat
91
for mounting an axle tube
92
. Mounted around an outer periphery of the axle tube
92
are a circuit board
93
and a stator bobbin
94
. The axle tube
92
includes a bearing mounted to an inner periphery thereof for rotatably holding a shaft
96
of a rotor
95
. The shaft
96
includes an annular groove
97
for engaging with a C-clip
98
.
In assembly, the axle tube
92
is extended through the circuit board
93
and the stator bobbin
94
and then engaged with the axle seat
91
of the casing
90
, and the shaft
96
of the rotor
95
is extended through the bearing in the axle tube
92
and then retained in place by means of engaging the C-clip
98
into the annular groove
97
of the shaft
96
. Thus, the rotor
95
, circuit board
93
, and stator bobbin
94
together constitute a brushless motor.
However, as illustrated in
FIG. 2
, mounting of the C-clip
98
into the annular groove
98
of the distal portion of the shaft
96
, so that a side of the C-clip
98
presses against an end face of the bearing, is difficult because the distal portion of the shaft protrudes only slightly beyond the bearing in the axle tube
92
. It was found that about 20%~30% of the brushless motors cannot pass the quality test after assembly, and the rejected brushless motors must be detached and retested and/or have their elements replaced. The first step of detachment is to remove the C-clip
98
from the annular groove
97
of the shaft
96
, and the C-clip
98
is thus damaged and cannot be used. In conclusion, detachment and assembly for such a conventional brushless motor is difficult and troublesome, and a C-clip is damaged in each detaching procedure. In addition, the C-clip
98
securely engaged in the annular groove
97
of the shaft
96
rotates together with the shaft
96
and thus generates noise as the C-clip
98
and the bearing would have friction therebetween.
SUMMARY OF THE INVENTION
It is the primary object of the present invention to provide a fixing structure for a rotor to allow easy assembly and detachment and to reduce rotational noise of the rotor.
A brushless motor in accordance with the present invention comprises a casing including an axle seat with an axle hole, the axle hole having a flange provided therein. An axle tube is engaged on the axle seat and includes a bearing mounted therein for rotatably holding a shaft of a rotor. The shaft includes a distal end that extends beyond an end face of the bearing, the distal end including a neck to thereby define an annular groove. An engaging member is mounted in the axle hole of the axle seat and retained in place by the bearing or the axle tube. The engaging member includes a hole having an inner diameter smaller than a diameter of the shaft of the rotor. An inner peripheral wall defining the hole of the engaging member includes a plurality of notches to thereby allow forcible passage of a distal end of the shaft through the hole of the engaging member. The peripheral wall of the hole of the engaging member is located in the annular groove of the shaft after the distal end of the shaft is passed through the hole of the engaging member.
Other objects, specific advantages, and novel features of the invention will become more apparent from the following detailed description and preferable embodiments when taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 3483888 (1969-12-01), Wurzel
patent: 4682065 (1987-07-01), English et al.
patent: 4987331 (1991-01-01), Horng
patent: 5679997 (1997-10-01), Matsuzawa et al.
patent: 5982066 (1999-11-01), Marracino et al.
patent: 6000919 (1999-12-01), Hsieh
patent: 6023117 (2000-02-01), Chen
patent: 6040649 (2000-03-01), Horng
patent: 6246140 (2001-06-01), Horng
patent: 6353274 (2002-03-01), Ogawara et al.
patent: 6368039 (2002-04-01), Wolfe et al.
patent: 6400054 (2002-06-01), Horng
Bacon & Thomas
Cuevas Pedro J.
Ramirez Nestor
Sunonwealth Electric Machine Industry Co. Ltd.
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