Fluid reaction surfaces (i.e. – impellers) – Having lubricating – sealing – packing or specific bearing...
Reexamination Certificate
2001-08-09
2003-05-20
Look, Edward K. (Department: 3745)
Fluid reaction surfaces (i.e., impellers)
Having lubricating, sealing, packing or specific bearing...
C416S104000, C416S205000, C415S229000
Reexamination Certificate
active
06565319
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fan, and more particularly to a fan having stable pre-loading device.
2. Description of the Prior Art
As shown in FIG.
1
(
a
), the conventional fan
10
includes a stator
20
, at least one bearing
30
, a rotor
50
, a shaft
60
and a spring
70
. The rotor
50
further includes a blade structure
55
. Besides, the shaft
60
couples the rotor
50
to the bearing
30
. As such, the shaft
60
enables the blade structure
55
of the rotor
50
to rotate. The shaft
60
passes through and compresses the spring
70
, and then is coupled to the bearing
30
. As such, the spring
70
applies a downward force, generally called pre-loading force, on the bearing
30
.
Referring to FIG.
1
(
a
) and FIG.
1
(
b
), the bearing
30
is positioned in the bottom of the stator
20
. In addition, the bearing
30
is composed of an inner ring
31
, a plurality of balls
32
and an outer ring
33
. The balls
32
couple the outer ring
33
to the outer periphery of the inner ring
31
. During the inner ring
31
rotates respective to the outer ring
33
, the balls
32
touch the inner ring
31
as well as the outer ring
33
and thus form the first contact
35
and the second contact
36
, respectively. However, the prior art suffers from the problem that the pre-loading force is unstable. For example, the contacts may shift and the pre-loading force fails to be kept constant. The problem and the reason are described in detail as follows. The blade structure
55
may move vertically or horizontally due to some reasons, such as the flow disturbs the blade structure
55
. In this case, the spring
70
maybe sometimes compressed and sometimes relaxed. As such, the spring
70
fails to apply constant pre-loading force on the bearing
30
, and the first contact
35
and the second contact
36
do not stay at the same positions. As a result, the fan suffers form shake, noise and abrasion.
Besides, prior art fails to adjust the pre-loading force according to the requirement of the user since the spring
70
has been formed previously and thus has no adjustable elastic coefficient.
Accordingly, there has been a strongly felt need for a novel fan having stable pre-loading to solve the above-mentioned problem. Besides, it is desired that the applied pre-loading force is adjustable.
SUMMARY OF THE INVENTION
The present invention discloses a fan having stable pre-loading device. Besides, according to the present invention, the pre-loading applied on the bearing of the fan is adjustable. The present fan includes a stator, at least one bearing, a rotor, a shaft, at least one elastic device and a rigid spacer. As shown in the enlarged portion, the stator includes a receptacle having a first thread formed on the inner periphery.
The bearing is positioned in the bottom of the receptacle. In addition, the bearing is composed of an inner ring, a plurality of balls and an outer ring. The balls couple the inner ring to the outer ring. During the inner ring rotates respective to the outer ring, the balls contact the inner ring and the outer ring, respectively.
The rotor further includes a blade structure. The shaft further includes a first terminal and a second terminal. Among these, the first terminal is coupled to the rotor. Therefore, the shaft enables the blade structure of the rotor to rotate. The elastic device (i.e. a spring) is taper and thus including one terminal having major diameter and another terminal having minor diameter. The thinner terminal, having minor diameter, is coupled to the inner ring of the bearing. The rigid spacer formed in the upper section of the receptacle is positioned on the spring and coupled to the terminal having major diameter. The second thread is formed on the outer periphery of the rigid spacer. As such, the second thread and the first thread couple the rigid spacer to the upper section of the receptacle. Besides, the second terminal passes through the central opening of the rigid spacer as well as the elastic device and then is coupled to the inner ring of the bearing. In this manner, the rigid spacer compresses the elastic device.
As described above, the blade structure does not affect the elastic device since the blade structure is separated form the elastic device. The elastic device compressed by the rigid spacer applies pre-loading force on the elastic device. If the distance between the rigid spacer and the bearing is kept constant, the pre-loading force applied on the elastic device is stable since the deformed length of the elastic device is also kept constant. As such, the first contact and the second contact of the bearing are maintained on the same position and do not move with the rotation of the blade structure. That is, the prior problems (i.e. shake, noise or abrasion) caused by the contacts moving with the vibration of the blade structure are effectively improved. Further, in the present invention, the distance between the rigid spacer and bearing is alterable and thus the pre-loading force according to the requirement of user is adjustable.
REFERENCES:
patent: 2953417 (1960-09-01), Horberg
patent: 3329845 (1967-07-01), Lear
patent: 3746472 (1973-07-01), Rupp
patent: 3816782 (1974-06-01), Dow et al.
patent: 4164690 (1979-08-01), Muller et al.
patent: 4203704 (1980-05-01), Saint-Amand
patent: 4621977 (1986-11-01), Markwardt
patent: 4719352 (1988-01-01), Miyatake et al.
patent: 4958945 (1990-09-01), Nakanishi
patent: 5997183 (1999-12-01), Horng
Birch & Stewart Kolasch & Birch, LLP
Delta Electronics , Inc.
Look Edward K.
McAleenan James M.
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