Asmo Co., Ltd.

Hiroyuki Furukoshi

Satoshi Morizaki

Shinichi Naito

Yoshihiro Adachi

Toshihiro Uchida

Hiroshi Matsumoto

Tatsuya Suzuki

Takahiro Sumiya

Akio Oshiro

Teruhisa Matsushita

Kazutomo Kakegawa

Masao Nakada

A motor control apparatus for controlling an operation of an electric motor has an operational temperature estimator and an operation controller. The operational temperature estimator estimates an estimated temperature of the electric motor. The operation controller disables to start the operation of the electric motor while the estimated temperature is within a predetermined operation start disable range, and enables to continue the operation of the electric motor when the estimated temperature increases into the operation start disable range.

Motor control apparatus

An ultrasonic motor drive apparatus includes a transformer having a primary coil and a secondary coil which drives a piezoelectric body of an ultrasonic motor. One end and the other end of the primary coil are connected to the drains of MOSFETS. The gates of the MOSFETs are connected to receive switching signals to alternately turn on and off electrical currents which flow in the primary coil. The sources of the MOSFETs are connected to the ground through ferrite beads, respectively. The ferrite bead generates a counter electromotive voltage so that the surge voltage which develops on the drain of the MOSFET at the time of turning off of the MOSFET is suppressed and high frequency oscillations are suppressed.

Ultrasonic motor drive apparatus having surge and oscillation suppressing member

When a motor is driven by a signal transmitted due to a switch turned on, a count value is added. When the motor is stopped, the count value is subtracted. When the count value is an upper limit value, the motor is continuously driven until the switch is changed to an off state. Subsequently, until the count value comes to a lower limit value, the motor is maintained in a stopped state even if the switch of the motor is changed to an on state. For this reason, generation of heat in the motor can be prevented.

Driving circuit of a motor

An ultrasonic motor includes a rotor and a rotor accommodated in a housing. The stator includes a piezoelectric element and the housing is secured to a base by screws. The rotor contacts the stator. The piezoelectric element vibrates the stator to rotate the rotor. An insulation plate is located between the stator and the base. An insulation washer is located between the stator and each screw. A rotary shaft is rotatably supported by the housing. The rotary shaft is coupled to the rotor with an insulation collar in between. Therefore, the stator and the rotor are electrically insulated from the housing and the rotary shaft. This arrangement reduces electromagnetic noise, which interferes with other electric devices, such as radios.

Ultrasonic motor

A microcomputer outputs a driving frequency signal to an oscillator circuit and the oscillator circuit oscillates at a driving frequency designated by the microcomputer. A switching control circuit outputs switching signals to an A-phase amplifier circuit and to a B-phase amplifier circuit at a predetermined timing. The A-phase amplifier circuit and the B-phase amplifier circuit each convert a DC voltage supplied by a voltage control circuit to an AC voltage and supply the same to two piezoelectric bodies of an ultrasonic motor. Due to the AC voltage being supplied to each of the two piezoelectric bodies, the ultrasonic motor is driven. At the start time of driving the ultrasonic motor, by gradually increasing the voltage level of the DC voltage outputted from the voltage control circuit and also gradually increasing the voltage level of a driving voltage to be supplied to the piezoelectric body of the ultrasonic motor, a stator and a rotor of the ultrasonic motor are gradually separated from each other. Further, in a case in which the voltage has been increased to a predetermined voltage level, the driving frequency is gradually lowered to increase the number of revolutions of the motor, thereby making it possible to lessen the vibration of the ultrasonic motor at the start time of driving. As a result, the generation of an audible sound can be prevented.

Driving circuit of ultrasonic motor

A drive circuit for an ultrasonic motor and, more particularly, a drive circuit for an ultrasonic motor which supplies the ultrasonic motor with drive signals of a predetermined frequency and controls the frequency of the drive signals to drive the ultrasonic motor is disclosed. The disclosed drive circuit for an ultrasonic motor drives an ultrasonic motor without generating a remarkable audible sound, even when a detection signal exceeds a predetermined level within a very short time due to the generation of an audible sound in the ultrasonic motor.

Drive circuit for ultrasonic motor

A drive circuit for driving an ultrasonic motor which maintains frequencies of drive signals for the ultrasonic motor within a drive frequency band. Generation of audible sound is thereby prevented. Further, it is possible to drive an ultrasonic motor in which irregularity of a waveform of a detection signal does not occur in an audible sound generating band.

Drive circuit for an ultrasonic motor having noise cancellation metals

A windshield wiper assembly which effects relatively smooth wiping motions as a pair of wiper blades are moved independently of each other such that the wiper blades do not interfere with each other. One wiper blade moving in a direction of approaching an overlapping area is stopped when that wiper blade has preceded the other wiper blade moving in a direction of moving away from the overlapping area by a first predetermined value or more. Meanwhile, the wiper blade moving in the direction of moving away from the overlapping area is stopped when that wiper blade has preceded the wiper blade moving in the direction of approaching the overlapping area by a second predetermined value or more exceeding the first predetermined value.

Windshield wiper assembly and synchronous signal generating device for

A wiper controller comprises a power source, a wiper drive mechanism, a power storage device having one potential detecting point, a charge circuit connected between the storage device and the power source, for charging the storage device. A discharge circuit is provided in parallel with the storage device for discharging the storage device. A drive control device controls the wiper through the drive mechanism. Either the charge circuit or the discharge circuit includes a switch for disconnecting that circuit. The other circuit includes a resistor for determining a corresponding charge or discharge time and for respectively charging or discharging the storage device. The present wiper controller further includes a switch control device for controlling the switch. The drive control device allows the wiper to reciprocate, when the potential at the detecting point reaches a predetermined value. The switch control device sets the switch on for a predetermined period of time after one reciprocative action of the wiper is completed, so that the battery is charged (or discharged) to initialize the potential at the detecting point.

Wiper controller

A wiper controller comprises a power source, a wiper drive motor, a power switch, a wiper switch, a position detector for detecting the position of a wiper on the windshield of a vehicle, a drive control circuit for controlling the power supply to the motor, and a switch circuit for controlling the power supply to the drive control circuit. The drive control circuit is connected to the power source, and controls the power supply to the motor from the power source, based on the ON/OFF status of the power switch and wiper switch, and also based on information from the position detector. The drive control circuit causes the wiper to stop at a predetermined position on the windshield. The switch circuit allows power to be supplied to the drive control circuit when the power switch is switched on, and further allows the power to be supplied, for a predetermined period of time, after the power switch is switched off.

Growing community of inventors

Toyohashi, Japan

Hiroyuki Furukoshi