Zexel Gmbh

Dai Nippon Printing Co., Ltd.

Hiroshi Ohsawa

Shinichi Ohi

Kouji Ando

Kzuyoshi Horiuchi

Yoshihide Gunji

Fuhito Umegaki

Masachika Masuda

Hiromichi Suzuki

Koji Tomita

Kazuyuki Miyano

Atsushi Kurahashi

Masami Takemasa

Tatsuo Haraguchi

Kazuyoshi Horiuchi

Hideaki Matsuzaki

Toshiya Yamashita

Yoshimi Sakai

Nobuo Sasagake

Yoichi Noguchi

Tadashi Okamoto

Yasunori Tanaka

A semiconductor device includes, a lead frame having a die pad and a plurality of leads each disposed around the die pad, a semiconductor element rested on the die pad of the lead frame, and bonding wires for electrically interconnecting the lead of the lead frame and the semiconductor element. The lead frame, the semiconductor element, and the bonding wires are sealed with a sealing resin section. The sealing resin section includes a central region provided over and around the semiconductor device, and a marginal region provided in the periphery of the central region. Thickness of the central region is greater than that of the marginal region.

Semiconductor device and manufacturing method therefor

In order to protect a brushless motor, heat generated at a switching device, in response to an abnormality, activates a protection device. The protection device includes a connecting line communicating between a source supply line and the switching device. The protection device is provided near the switching device such that it can sense heat at the switching device with a high degree of sensitivity. Thus, when excessive heat is generated at the switching device, the protection device reaches a specific temperature, whereby the source supply line becomes cut off from the switching device, thereby immediately stopping the operation of the brushless motor.

Brushless motor

A pulse width of a drive pulse of a brushless motor is modulated in correspondence to a setting signal for setting the rotation rate. Switching control for the current supplied to exciting coils is implemented by using an output signal from Hall elements for detecting the position of the rotor and the drive pulse. Correction of the pulse width of the drive pulse is implemented to ensure that the average voltage is maintained at a constant level even when the source voltage fluctuates so that stable rotation can be maintained over the entire rotation rate range even when the source voltage supplied to the brushless motor fluctuates and so that the fuse can be prevented from melting and the motor can be prevented from becoming damaged, which may otherwise be caused by a fluctuating source voltage.

Drive control apparatus for brushless motor

An object of preventing a reduction in the output efficiency of a motor in the high speed rotation range and reducing the noise of the motor in the low speed rotation range is to be achieved. Since, if a signal that corresponds to the rotation rate has a value equal to or smaller than a specific value, the timing with which a switch performs switching is retarded relative to the timing used when the signal corresponding to the rotation rate has a value larger than the specific value, once the operation shifts to the low speed rotation range, the switching timing is retarded to shift from the setting that gives priority to efficiency, to the setting for achieving noise reduction as long as the switching timing is set in advance so that an optimal output efficiency is achieved in the high speed rotation range.

In order to prevent the performance of a motor from deteriorating due to a change in which the rotation rate of its rotor is to be increased suddenly, in a brushless motor in which a drive pulse whose pulse width is modulated in correspondence to a rotation rate setting signal input from the outside is formed and switching control is performed on the current supplied to the exciting coils by using output signals from the Hall elements that detect the position of the rotor and the drive pulse, the pulse width of the drive pulse is changed gradually and greatly until it reaches the pulse width that corresponds to the rotation rate setting signal when the upward change in the rotation rate of the rotor is to be large.

An EMI prevention circuit has a first ground pattern grounded to a car body and a second ground pattern connected to the first ground patter by way of an EMI condenser. A large-current ground line through which a large current flows is connected to the first ground pattern by way of an EMI condenser. A small-current ground line in which a small current flows is directly connected to the second ground pattern without using any EMI condenser in between. Because of this, even when a ground potential of the first ground pattern fluctuates by a noise due to driving a large-current load, since the second ground pattern is directly connected to a ground side of a car battery, the second ground pattern is maintained at a ground potential of the car battery and does not fluctuate. Also, when any high-frequency noise invades from a radio communication set and a portable telephone set, since the second ground pattern is connected to the first ground pattern by way of an EMI condenser, the high-frequency noise is discharged to the car body through the first ground pattern.

EMI prevention circuit for a car-mounted electronic control unit

The present invention offers a simple structure that facilitates the mounting of bearings, that maintains lubricating oil at a sufficient level in the bearing portions and that maintains an optimal distance between a rotor and a case housing for preventing freezing, for preventing reduction of the capacity and for preventing noise. Bearing stoppers provided between the bearings of the brushless motor and the bearing holders, which hold the upper end edge of each bearing, are secured at a projection formed at the internal circumferential surface of each bearing holder. A felt, which comes in contact with the lower portion of each bearing stopper and also comes in contact with the bearing at one side is provided, with holes communicating with the felt formed at the lower surface of the bearing stopper. In addition, the lower limit of the distance h between the lower end of the rotor and the upper end surface of the case housing is set at 1.5 mm. This prevents water from forming a connection between the rotor and the case housing due to capillary action and surface tension. In addition, the upper limit of the distance h is set at or under 8 mm, which represents the critical point for the capacity and the noise. This ensures that the capacity is maintained at a satisfactory level and also prevents noise from increasing. Moreover, a washer group, which comprises at least one each of a resin washer, a rubber washer and a POM (polyoxymethylene) washer is provided between a sensor magnet that is secured to the lower end of the rotating shaft and the lower bearing.

Brushless motor having lubrication system for upper and lower bearings

In an R-C filter for preventing a noise signal from entering a power supply system through its output circuit, a circuit component acting as a resistive element for the filter is connected in series with the output circuit and a capacitive element is connected between one portion of the circuit component and ground to form an R-C type filter. A wiring member, a printed wiring foil, a through-hole member, a semiconductor device or other such circuit component can be used, as the circuit component acting as the resistive element for constituting the R-C type filter.

Power supply filter for preventing noise signal from entering power

For enabling discrimination of whether or not a blower motor is in a locked state to be conducted promptly and reliably irrespective of the motor speed, a blower system comprises a discrimination circuit for discriminating whether or not the blower motor is in a locked state based on change in the position of the rotor of the motor, and the discriminating time period between motor locking and output of a discrimination signal is determined to be shorter for a higher set rotational speed of the motor in response to the speed setting operation of a motor speed setting device.

Blower system for vehicle air-conditioners

A stepping motor control device for an automobile air-conditioning system has a key-off home-position setting unit of a stepping motor for driving an air-conditioning door in response to switching of a key switch of the automobile off. The key-off home-position setting unit, responsive to switch of the key switch off, drives the stepping motor so that the air-conditioning door comes to a full-close position or a full-open position, stores data indicative of the full-close or full-open positions, as a current position of the air-conditioning door in a memory, and thereby finishes a home-position setting of the stepping motor. The key-off home-position setting unit is supplied with power from a power source under control of a timer for a prescribed time within which a home-position setting can be finished. When the key switch is turned on, the key-on control unit judges whether or not a current position of the air-conditioning door given by the key-off home-position setting unit is stored in the memory, and starts a normal air-conditioning control without performing a home-position setting if the current position is stored.

Stepping motor control device for automobile air-conditioning system

A pulse motor control device comprises, as additional component parts, a power-off detecting circuit, and a turning-off circuit. The power-off detecting circuit detects, when a driving switch is turned off, a dropping of a voltage supplied to a driving circuit and outputs a power-off detection signal. The turning-off circuit includes diodes and a control resistor. The diodes are connected respectively to control terminals of all driving transistors of the driving circuit. When the control transistor is turned on in response to the power-off detection signal, voltages of control terminals of the driving transistors are dropped to the ground level through the diodes, thereby turning off the driving transistors.

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Konan, Japan

Hiroshi Ohsawa