Pumps – Condition responsive control of pump drive motor – Responsive to pump or pump fluid temperature
Reexamination Certificate
2001-03-26
2002-12-03
Freay, Charles G. (Department: 3746)
Pumps
Condition responsive control of pump drive motor
Responsive to pump or pump fluid temperature
C417S044100, C417S368000, C417S369000, C417S423100, C417S423140
Reexamination Certificate
active
06488475
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an electric blower mainly used for an electric cleaner, and in particular, it aims at reducing the size of a main body of the electric cleaner to improve usability.
BACKGROUND OF THE INVENTION
As electric cleaners of the prior art, there are used mainly those of the un-circulated exhaust type shown in FIG.
24
and those of the circulated exhaust type shown in FIG.
25
. An outline of the electric cleaners of the prior art will be described hereinafter.
An electric cleaner
1
of the un-circulated exhaust type shown in
FIG. 24
has a hose
3
connected detachably to its main body
2
. Another end of the hose
3
is provided with an end pipe
5
having a control section
4
. An extension pipe
6
is attached to the end pipe
5
, and a head of the extension pipe
6
is connected with a suction nozzle
7
. In the cleaner's main body
2
, there is a dust chamber
8
formed in communication with the hose
3
. Also provided behind the dust chamber
8
are an electric blower
10
disposed in such a manner that a suction port
9
faces toward the dust chamber
8
, and a power supply unit
11
housing a cord for connection to commercial power supply, a battery, or the like.
FIG. 25
shows an electric cleaner of the circulated exhaust type. Like reference numerals are used to designate components like those of the un-circulated exhaust type. The circulated exhaust type further has the following structure in addition to the structure of the un-circulated exhaust type. A main body exhaust path
13
is formed from a discharge port
12
of an electric blower
10
to a connecting area of a cleaner's main body
2
for connection to a hose
3
. Further, there are a suction passage
14
representing an airflow pass in communication with a dust chamber
8
leading to a suction port
9
of the electric blower
10
, and an exhaust passage
15
for delivering exhaust flow of air expelled from the discharge port
12
at a rear side of the electric blower
10
via the main body exhaust path
13
to a front end of the hose
3
, formed respectively in the hose
3
, an extension pipe
6
, and a suction nozzle
7
. The passages are constructed so as to be independent with respect to each other, and also separated from the open air space.
The electric blower will be described now.
Most motor units for electric blowers used heretofore in the electric cleaners have been commutator motors, which are the type generally referred to as universal motors. Lately, inverter motors have been used for the purpose of achieving reduction in size and weight by increasing speed, easiness of controlling rotational speed, cutback in power consumption, suppressing temperature rises, and so on. However, an inverter motor has an increased number of power devices in its circuit, as compared to a commutator motor. For an inverter motor consisting of windings of three phases, for instance, six power devices are required. It is therefore necessary to cool the plurality of power devices efficiently.
A structure of the conventional electric blower will be described hereinafter.
As shown in
FIG. 26
, the electric blower
10
comprises a motor unit
16
and a fan unit
17
. A rotor
22
constructed of an armature core
19
, provided with an armature winding
18
and a commutator
20
mounted on a shaft
21
, is installed on an impeller-side bracket
25
and a motor-side bracket
26
in a freely rotatable manner with bearings
23
and
24
. The brackets
25
and
26
compose an enclosure of the motor unit
16
. A stator
29
provided with a field winding
28
on a field core
27
, and a holder
30
carrying a carbon brush (not shown in the figure) are secured to the bracket
26
.
The fan unit
17
comprises an impeller
31
attached to the shaft
21
of the motor unit
16
, an air guide
32
disposed around the impeller
31
to form an airflow path for leading a flow of the air delivered from the impeller
31
to an interior of the motor unit
16
while gradually recovering its pressure, and a casing
33
covering them. The fan unit
17
is mounted integrally to the bracket
25
. The bracket
25
is also provided with a cooling air discharge port
34
in a part thereof for discharging a portion of the airflow delivered from the impeller
31
, without passing through the interior of the motor unit
16
.
A circuit unit
35
for controlling electric power supplied to the electric blower
10
comprises a circuit board
38
housed in a circuit board enclosure
39
, and is connected with a power supply wire
36
connected to the power supply unit
11
, a signal wire
37
for transmitting an operating signal from the control section
4
, and so on. The circuit unit
35
is mounted on the bracket
25
of the electric blower
10
with a screw
40
. A radiating fin
42
for a power device
41
or a heat-generating component such as a triac is arranged in the circuit unit
35
in an airflow path between a cooling air inflow port
43
and a cooling air outflow port
44
in the circuit board enclosure
39
, where a flow of air expelled through the cooling air discharge port
34
of the fan unit
17
flows through.
When the electric cleaner
1
is operated, the electric blower
10
produces a suctioning force. Contaminated air containing dust is suctioned from an inlet port of the suction nozzle
7
, and reaches to the dust chamber
8
in the cleaner's main body
2
through the suction passage
14
in the suction nozzle
7
, the extension pipe
6
and the hose
3
. The air is then guided to the electric blower
10
, after the dust and the like are removed. At the same time, the power device
41
is cooled by the flow of discharge air expelled through the cooling air discharge port
34
.
As described, the conventional electric cleaner divides the flow of air that passes through the fan unit
17
into a flow of air to the motor unit
16
and another flow of air to cool the radiating fin
42
in order to cool the power device
41
, etc. efficiently with the radiating fin
42
of small size, regardless of whether it is the circulated exhaust type, or not. Thus, the structure needs to be such that the radiating fin
42
or the circuit unit
35
is placed downstream of the cooling air discharge port
34
of the fan unit
17
. It is also necessary to separate only the power device
41
portion from the circuit unit
35
, to further enhance the heat dissipation. They become a structural problem within the cleaner's main body
2
, making it difficult to reduce the size of the cleaner's main body
2
.
The following description pertains to an electric blower controlled by an inverter.
An electric blower
10
comprises an inverter motor
47
consisting of a motor unit
45
and an inverter circuit unit
46
, and a fan unit
48
, as shown in FIG.
27
. The electric blower
10
is held so that it is pressed against a retaining rib
53
on a partition
52
having a large number of through holes
51
and separating the electric blower
10
from a dust chamber
8
via a support rubber
50
placed on an outer periphery of a casing
49
.
A rotor
56
provided with a permanent magnet
54
and a shaft
55
is installed on an impeller-side bracket
59
and a motor-side bracket
60
in a freely rotatable manner with bearings
57
and
58
. The bracket
59
and the bracket
60
are connected to compose an enclosure of the motor unit
45
. A stator
63
constructed of a core
19
provided with a stator winding
62
in a plurality of slots formed in a manner to confront the permanent magnet
54
, is secured to the bracket
60
. The rotor
56
, the brackets
59
and
60
, and the stator
63
compose the motor unit
45
.
The inverter circuit unit
46
for controlling the inverter motor
47
is mounted on a circuit board
66
, which is connected with a power supply wire
64
in connection to the power supply unit
11
, a signal wire
65
for transmitting an operating signal and a rotating-speed control signal for the cleaner's main body
2
, and the like. It is disposed in the vicinity of t
Morishita Kazuhisa
Murata Yoshitaka
Nishimura Tsuyoshi
Tokuda Tsuyoshi
Yamaguchi Seiji
Freay Charles G.
Matsushita Electric - Industrial Co., Ltd.
Sayoc Emmanuel
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