Pumps – Condition responsive control of pump drive motor – By control of electric or magnetic drive motor
Reexamination Certificate
2002-04-09
2004-04-13
Yu, Justine R. (Department: 3746)
Pumps
Condition responsive control of pump drive motor
By control of electric or magnetic drive motor
C417S231000, C417S423700, C417S423140, C417S423800, C417S352000
Reexamination Certificate
active
06719534
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application is related to Japanese Patent Applications No. 2001-112252 filed on Apr. 11, 2001, No. 2001-178969 filed on Jun. 13, 2001, and No. 2002-28455 filed on Feb. 5, 2002, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a vehicle blower unit used in an installation space narrow in a vertical direction. More particularly, the present invention relates to a structure of a flat-type blower unit for a seat air conditioner, for introducing conditioned air in an air conditioning unit to a surface of a seat cushion.
2. Description of the Related Art
A blower unit
500
for blowing air toward a seat, shown in
FIG. 21
, has a brushless motor
501
for rotating a centrifugal fan, and a motor drive circuit
502
for controlling a rotational speed of the brushless motor
501
according to an input signal from an external microcomputer (not shown).
The brushless motor
501
is constructed by a stator
504
having three-phase armature windings
503
, an outer rotor
506
having a plurality of permanent magnets
505
, a rotary shaft
507
which rotates integrally with the outer rotor
506
and has a fan boss portion of a centrifugal fan screwed on its outer periphery, and the like. The motor drive circuit
502
has a circuit board
513
on which a plurality of MOS-FETs (switching device)
511
for sequentially passing a current through the three-phase armature windings
503
and electric parts
512
such as a smoothing capacitor are mounted. The circuit board
513
is covered by a drive circuit cover
514
. Further, the drive circuit cover
514
is provided with a radiating heat sink
515
for radiating the heat of the plurality of MOS-FETs
511
into a unit case. The plurality of MOS-FETs
511
is forcibly cooled by cool air generated by the rotation of the centrifugal fan, at a downstream air side of the centrifugal fan.
However, in the above-described blower unit
500
, the radiating heat sink
515
for radiating the heat generated by the plurality of MOS-FETs
511
into air is mounted to be exposed into the unit case, to be cooled by an air flow generated by the rotation of the centrifugal fan. Accordingly, the air flow in the unit case is disturbed, so that a high pressure loss causes, and an air-blowing amount is reduced. Further, since the radiating heat sink
515
is disposed to protrude into the unit case, a pressure pulsation is caused, and therefore, whiz noise may be caused. In addition, because the radiating heat sink
515
is used in the blower unit
500
, the number of the components is increased in the blower unit
500
, and cost of the blower unit
500
is increased.
SUMMARY OF THE INVENTION
In view of the foregoing problems, it is an object of the present invention to provide a vehicle blower unit in which a motor drive circuit is disposed to contact a motor attachment bracket so that the number of component parts can be reduced by using the motor attachment bracket as a radiating heat sink.
It is an another object of the present invention to provide a vehicle blower unit capable of realizing a low noise level by a cooling system using natural convection.
It is a further another object of the present invention to provide a vehicle blower unit capable of improving EMC and taking measures against EMI by covering the motor drive circuit with the motor attachment bracket.
It is a further another object of the present invention to provide a vehicle blower unit having a centrifugal fan, which can effectively reduce a noise level.
According to the present invention, in a vehicle blower unit having a fan and a motor for rotating the fan, a motor drive circuit for controlling a rotation speed of the motor has a heat-generating member which generates heat when being operated, a motor attachment bracket is disposed for attaching the motor to a unit case, and the motor drive circuit is disposed to contact the motor attachment bracket. Accordingly, by making the motor drive circuit abut against the motor attachment bracket, it is possible to use the motor attachment bracket as a radiating heat sink for radiating heat generated by the heat-generating member into air. Because an additional radiating heat sink is unnecessary and the motor attachment bracket can be used as the radiating heat sink for radiating heat to air, it is possible to reduce the number of component parts and the assemble steps. Therefore, it is possible to realize cost reduction and to improve mounting performance, in the vehicle blower unit.
Preferably, the motor attachment bracket is disposed to cover the motor drive circuit. Therefore, it is also possible to use the motor attachment bracket as a drive circuit cover for covering the motor drive circuit. Thereby, an additional drive circuit cover is unnecessary, so it is possible to reduce the number of component parts and the assembling steps. Further, noises radiated from the motor drive circuit can be effectively reduced by the motor attachment bracket used as the drive circuit cover.
Further, the motor attachment bracket is made of a metal material having a thermal conductivity higher than a predetermined conductivity. Therefore, by covering the motor drive circuit with the motor attachment bracket made of a metal material, it is possible to reduce radiant noises (to take measures against EMI). Further, by providing the motor drive circuit with an anti-EMI LC filter for preventing radio wave interference and an electric noise, it is possible to effectively suppressing the radio wave interference and the electric noise. That is, it is possible comparatively easily to improve EMC and to take measures against EMI.
Preferably, the motor attachment bracket is disposed outside the unit case along an outer wall surface of the unit case, to protrude radial outside from the motor. Therefore, a noise level can be reduced while the motor attachment bracket can be cooled outside the unit case using natural convection. Further, the unit case, the motor drive circuit and the motor attachment bracket are disposed to have a dimension smaller than a predetermined valve in a vertical direction. Therefore, the dimension of the blower unit in the vertical direction can be effectively reduced, and the blower unit can be readily mounted in a narrow space between a seat cushion of a vehicle seat and a floor of the vehicle. In this case, the blower unit can be effectively used for a vehicle seat.
Preferably, the heat-generating member includes a plurality of switching devices for passing a current through polyphase armature windings in sequence. By passing the current through the polyphase armature windings in sequence, a rotating magnetic field is generated in the motor. Further, by controlling the rotating magnetic field in accordance with the relative rotational position and the rotational speed of a rotor, a permanent magnet disposed on the rotor is attracted by the rotating magnetic field to generate a torque. The motor drive circuit is electrically connected to one of a computer for sending a digital signal for controlling the rotational speed of the motor to the motor drive circuit, and a variable resistor for sending an analog signal for controlling the rotational speed of the fan motor to the motor drive circuit.
Preferably, the fan is a centrifugal fan having a plurality of blades around an axial direction of the centrifugal fan, the centrifugal fan is disposed such that air sucked in the axial direction is blown toward a radial outside, the unit case includes a scroll casing for accommodating the centrifugal fan, the scroll casing has a nose portion from which a scroll shape of the scroll casing starts, the centrifugal fan has a fan height (H) in the axial direction, and a ratio (H/D) of the fan height to a fan diameter (D) of the centrifugal fan is equal to or lower than 0.5. In addition, the centrifugal fan is disposed in the scroll casing to have a dimension between the centrifugal fan and the nose portion of the scroll casin
Denso Corporation
Harness Dickey & Pierce PLC
Sayoc Emmanuel
Yu Justine R.
LandOfFree
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