Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2001-06-29
2003-01-28
Freay, Charles G. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
C417S423140
Reexamination Certificate
active
06511303
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates especially to a blower suitable in the application for cooling office automation equipment.
2. Description of the Prior Art
Conventionally, the double row bearing device employed in the blower for cooling the office automation equipment includes a pair of ball bearings
102
and
103
fit on a shaft
101
of the motor as shown in FIG.
8
.
Inner rings
102
a
,
103
a
of each ball bearing
102
,
103
are loose fit to the shaft
101
, and outer rings
102
b
,
103
b
are also loose fit within the sleeve
104
being the bearing housing.
A compressed coil spring
106
for applying pre-load to both ball bearings is interposed between the outer surface of the inner ring
102
a
of the left ball bearing
102
disposed adjacent the yoke
105
and the front face plate
105
a
of the yoke
105
integrally connected to the front face plate
108
a
of the impeller
108
. A stop ring
107
for retaining the ball bearing
103
is provided around the right end of the shaft
101
and secured thereto.
However, in the case of the pre-loading means as shown in
FIG. 9
, the clearance defined between the yoke
105
and the ball bearing
102
is very narrow, making it difficult to incorporate the compressed spring
106
into the clearance. Further, the necessity of incorporation of the spring into the clearance upon assembling the blower will make the assembling operation complicated. The level of the pre-loading force depends exclusively upon the distance between the yoke
105
and the bearing
102
. Setting such distance is difficult and therefore, applying suitable amount of pre-loading force is difficult.
The sleeve
104
has at both ends thereof larger inner diameter portions
104
a
,
104
b
for accommodating the outer rings of the ball bearings. Each of the larger inner diameter portions includes a shoulder respectively to which the outer ring of the ball bearing will be abutted. When the larger inner diameter portions
104
a
,
104
b
are more or less eccentrically formed with respect to the sleeve, the rotational movement of the shaft is also effected eccentrically, and generates vibrations or noise and therefore a precise machining on the larger inner diameter portion is required.
As it can be seen from the above, the blower employing the double row bearing device of the prior art requires a pair of ball bearings including an inner and an outer ring. A complicated operation for inserting the pre-loading spring is required. This involves a high cost for manufacturing the bearing device.
The bigger the diameter of the motor shaft is, the higher is the rigidity of the shaft, and thus the rotational run out is reduced and a quiet motor with high durability can be obtained. However, the diameter of the shaft of the bearing device of the prior art is smaller than that of the sleeve by twice the sum of the thickness of the inner and outer rings of the ball bearings fit around the shaft. Therefore, it is difficult to provide durability, prevent rotational run out, and reduce generation of vibrations or noise.
Accordingly, the object of the present invention is to provide a blower including a bearing structure wherein the number of components is reduced, assembly is easy, manufacturing cost is reduced, and the diameter of the shaft is increased being good at its durability, further eliminating rotational run out and providing superior quietness.
SUMMARY OF THE INVENTION
These and other objects are achieved by a blower in accordance with the first aspect of the present invention having an impeller adapted to be rotated upon energizing the blower comprising;
a bearing device for supporting a rotational center portion of the impeller, the bearing device including;
a sleeve,
a stepped shaft including a larger diameter portion and a reduced diameter portion provided at one end thereof,
the first inner raceway groove formed at an appropriate position around the outer peripheral surface of the larger diameter portion,
the first outer raceway groove formed on an inner peripheral surface of the sleeve so as to correspond with the first inner raceway groove,
balls of the first row interposed between the first and second grooves,
an inner ring slidably fit over the reduced diameter portion,
the second inner raceway groove formed around an outer peripheral surface of the inner ring,
the second outer raceway groove formed on the inner peripheral surface of the sleeve so as to correspond with the second inner raceway groove,
balls of the second row interposed between the second inner and outer grooves,
a stop ring provided around the inner periphery of the distal end of the reduced diameter portion, and
a pre-loading spring interposed between the stop ring and an end surface of the inner ring to provide a suitable amount of pre-loading force to the inner ring.
The blower in accordance with the second aspect of the present invention comprising;
a frame including a base connected through stays to the frame so as to be positioned at the central portion of the frame,
a cylindrical bearing holder formed integrally with the base to extend therefrom forwardly,
a stator including an iron core and a coil and mounted on the exterior of the cylindrical bearing holder,
an impeller including a front face plate, a flange formed over the outer periphery of the front face plate, and suitable numbers of blades provided on the outer periphery of the flange,
a yoke including a front face plate to which the front face plate of the impeller is secured, a flange formed over the outer periphery of the front face plate, a magnet mounted on the flange, and
a bearing device for supporting the central portion of the yoke through a shaft of the bearing device to which the central portion of the yoke is fit and secured thereto, the bearing device including;
a sleeve,
a stepped shaft including a larger diameter portion and a reduced diameter portion provided at one end thereof,
the first inner raceway groove formed at an appropriate position around the outer peripheral surface of the larger diameter portion,
the first outer raceway groove formed on an inner peripheral surface of the sleeve so as to correspond with the first inner raceway groove,
balls of the first row interposed between the first and second grooves,
an inner ring slidably fit over the reduced diameter portion,
the second inner raceway groove formed around an outer peripheral surface of the inner ring,
the second outer raceway groove formed on the inner peripheral surface of the sleeve so as to correspond with the second inner raceway groove,
balls of the second row interposed between the third and fourth grooves,
a stop ring provided around the inner periphery of the distal end of the reduced diameter portion, and
a pre-loading spring interposed between the stop ring and an end surface of the inner ring to provide a suitable amount of pre-loading force to the inner ring.
The blower in accordance with the third aspect of the present invention comprising;
a frame including a base connected through stays to the frame so as to be positioned at the central portion of the frame,
a cylindrical bearing holder formed integrally with the base to extend therefrom forwardly,
a stator including an iron core and a coil and mounted on the exterior of the cylindrical bearing holder,
an impeller including a front face plate, a flange formed over the outer periphery of the front face plate, and suitable numbers of blades provided on the outer periphery of the flange,
a yoke including a front face plate to which the front face plate of the impeller is secured, a flange formed over the outer periphery of the front face plate, a magnet mounted on the flange, and
a bearing device for supporting the central portion of the yoke through a sleeve of the bearing apparatus to which the central portion of the yoke is fit and secured thereto, the bearing device including;
a sleeve, a stepped shaft including a larger diameter portion and a reduced diameter portion provided at one end thereof,
the first inner raceway groove f
Belena John F
Freay Charles G.
Gopstein Israel
Minebea Kabushiki-Kaisha
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