Abstract: To accomplish conflicting goals of weight and noise reduction in a small motor, a plastic motor case with a flange is divided into two parts in the axial direction and an elastic body is mounted between the motor body and motor case so as to absorb vibration. A thin end bracket and motor housing can be used and not only for weight reduction but also for noise reduction can be realized.

Abstract: A blower of an automotive air conditioner has a lower casing a part of which is formed is a plastic housing for a motor and a porous member in the form of a flat plate disposed at a position where the plastic housing and an upper casing of the blower abut against each other. An air layer is defined between the flat-plate porous member and the lower casing to add a muffling function.

Abstract: A centrifugal fan with a noise suppressing arrangement includes a fan, a motor for rotating the fan and a scroll casing for accommodating the fan, the scroll casing is formed of a first scroll casing member covering the fan and a second scroll casing member forming the bottom part of the scroll casing, the second scroll casing member being provided with at the center thereof a cylindrical housing for holding the electric motor, and further includes a porous sound absorbing member having elasticity sandwiched and secured between the first scroll casing member and the second scroll casing member whereby the combination of the porous sound absorbing member and an air layer formed between the porous sound absorbing member and the inner bottom wall of the second scroll casing member suppresses noises caused by rotation of the fan.

Abstract: Cooling air is introduced through an opening in a wall portion of the motor housing radially opposing the commutator. A deflecting surface is provided for deflecting the cooling air entering the motor through the opening away from the commutator and toward the armature so as to prevent direct contact of dust and moisture in the cooling air with the commutator.

Abstract: An air induction system for an automotive air-conditioner has an air switching housing connected to the suction opening of a blower casing. The housing is provided with a fresh outdoor air induction opening formed in the top wall opposing the suction opening, and a recirculated indoor air induction opening formed in a side wall adjacent to the top wall. An air-switching door is provided for selectively opening and closing the outdoor air induction opening and the indoor air opening. The air-switching door is foldable substantially at its mid portion so that, when the door closes the indoor air induction opening, it is folded to provide a small effective area, while, when it closes the outdoor air induction opening, it is extended to provide a large effective area. The system further has auxiliary indoor air induction openings formed in other side walls and an accordion-type shutter for selectively closing and opening the auxiliary indoor air induction opening.

Abstract: Provided is a brushless-motor fan unit having a centrifugal fan and a scroll casing enclosing the centrifugal fan therein. The rotor of the brushless-motor is carried by the centrifugal fan. Further, the motor shaft carrying the centrifugal fan is supported at its front and rear ends by the scroll casing. With this construction, the motor housing can be eliminated so as to obtain a compact centrifugal type motor fan unit in a small thickness as a whole.

Abstract: A rotational speed control circuit for a D.C. motor includes a power transistor with its emitter-collector path connected in series with the D.C. motor and a power supply. A base current of the power transistor is controlled by an output of a differential amplifier which is supplied at its one of input terminals with a constant voltage and at the other input terminal with a voltage changing in accordance with a terminal voltage of the D.C. motor. Further the latter input terminal of the differential amplifier is given a variable bias potential by means of an adjustable mechanism. By this circuit configuration, the rotational speed of the D.C. motor can be continuously and proportionally adjusted over a wide range and once the rotational speed is set to predetermined value by the adjustable mechanism, a stable and constant speed control for the D.C. motor can be achieved.