Abstract: A method and an apparatus accurately detect a rotor angle of a DC brushless motor by using a first-order difference of a detected value of a phase current. A periodic signal causing the total sum of output voltages in three control cycles to become zero is superposed over a drive voltage under current feedback control. The drive voltage is held at a constant level during the three control cycles. The phase difference between an actual value and an estimated value of a rotor angle is calculated, using the first-order differential current in each control cycle, and the estimated value of the rotor angle is calculated by follow-up computation of an observer, using the phase difference.

Abstract: A method of adjusting the temperature properties of piezoelectric devices and oscillation circuits which have a third-order function temperature property and the point of inflection of the third-order function temperature property outside the normal usage temperature range. The local maximum point or local minimum point temperature located in the normal temperature range is regarded as the peak temperature of the apparent second-order function temperature property, and the peak temperature is adjusted to the optimum value in the normal temperature range by rotating the temperature property around the point of inflection located outside the normal temperature range by adjusting the first-order coefficient.

Abstract: In a motor stator, teeth radially project from an annular stator core, and a plurality of slots formed between adjacent teeth are skewed. Phase windings alternately pass through slots having different skew directions, wherein the length of bridging portions, which do not contribute to generation of torque, is short and the length of the portions which are located in the slots, and which contribute to the generation of torque, is long. Further, the phase windings are bent at an obtuse angle at opposite ends of the bridging portions.

Abstract: A vibration gyro sensor is provided which is capable of generating time information and detecting an angular velocity. A driving signal for driving a tuning fork piezoelectric vibrating reed is generated based on an excitation signal generated by an oscillation circuit. An angular velocity signal is obtained based on a detection signal generated by a detection electrode of the tuning fork piezoelectric vibration reed. The excitation signal generated by the oscillation circuit is input to a divider such that a timer clock signal is generated.

Abstract: An inspection voltage imposer generates an inspection voltage by multiplying fundamental voltage string data in which a certain voltage output pattern where an average of output voltage levels in one period becomes 0 is set by data of a modulation signal whose value varies every period and impose the inspection voltage on a drive voltage of a motor. When the inspection voltage is imposed on the drive voltage of the motor, an angle detector detects the rotor angle of the motor based on the fundamental voltage string data, a variation of an inspection current and the data of the modulation signal in respective control cycles.

Abstract: A multiplexer of a transmission section generates a clock signal by multiplying a reference clock signal of a digital image signal by a predetermined number ‘K’. A parallel digital image signal is converted into a serial digital signal on the basis of the clock signal, and the serial digital signal is converted into an optical signal in an optical transmission section for transmitting. A demultiplexer extracts a reception clock signal from a serial digital reception signal which is converted into an electric signal in an optical reception section of a reception section, the serial digital reception signal is converted into a parallel signal and a signal corresponding to the parallel digital image signal on the basis of the reception clock signal, and a clock signal corresponding to the reference clock signal is recovered by multiplying the reception clock signal by ‘1/K’.

Abstract: A control apparatus for a brushless DC motor that rotatably drives the brushless DC motor including a rotor having a permanent magnet, and a stator having stator windings of a plurality of phases that generate a rotating magnetic field for rotating the rotor, by a current passage switching device constituted by a plurality of switching elements and performing successive commutation of current to the stator windings. The control apparatus includes: an angular error calculation device for calculating a sine value and a cosine value of an angular difference between an estimated rotation angle with respect to the rotation angle of the rotor and an actual rotation angle, based on a line voltage that is a difference between phase voltages of the plurality of phases on an input side of the stator winding and phase currents of the plurality of phases; and an observer for calculating the rotation angle of the rotor based on the sine value and the cosine value of the angular difference.

Abstract: A claw pole motor stator includes teeth for N phases (N being a natural number of 3 or more), for example, U-phase, V-phase, and W-phase teeth juxtaposed in an axial direction, return paths for interconnecting the U-phase, V-phase, and W-phase teeth, and (N?1) annular slots formed between the U-phase, V-phase, and W-phase teeth. A U-phase coil and one V-phase coil are housed in one annular slot, and another V-phase coil and a W-phase coil are housed in the other annular slot. In this way, only N sets of teeth and N?1 annular slots are provided for N phases, and thus it is possible to minimize the thickness in the axial direction of the stator compared with a conventional stator which requires 2N sets of teeth and N annular slots for N phases.

Abstract: A method of adjusting the temperature properties of piezoelectric devices and oscillation circuits which have a third-order function temperature property and the point of inflection of the third-order function temperature property outside the normal usage temperature range. The local maximum point or local minimum point temperature located in the normal temperature range is regarded as the peak temperature of the apparent second-order function temperature property, and the peak temperature is adjusted to the optimum value in the normal temperature range by rotating the temperature property around the point of inflection located outside the normal temperature range by adjusting the first-order coefficient.

Abstract: A motor controller implements alternately a feedback control for d axis current and a feedback control for q axis current using an estimate value of a rotor angle in different control cycles. Then, the motor controller calculates a sine reference value which corresponds to a sine value of an angle which is twice a phase difference between an actual value and an estimate value of a rotor angle and a cosine reference value which corresponds to a cosine value of the angle which is twice the phase difference based on variations of the d axis actual current and q axis actual current and levels of d axis voltage and q axis voltage in a control cycle in which feedback controls are implemented for d axis current and q axis current and detects a rotor angle using the sine reference value and the cosine reference value so calculated.

Abstract: To provide a power transmission device that can increase the range of speed variation between an engine and a power output shaft and effectively achieve reduction in size and cost of the device arrangement. The speed reduction ratios from an engine 1 to first output shaft 4c, 5c of first and second power distributors 4, 5 are different from each other. A speed change unit 10 is provided between the first output shaft 4c of the first power distributor 4 and a power output shaft 11 linked with driving wheels 2, 2 of the vehicle, and rotation transmission therebetween is achieved at a plurality of stages of speed reduction ratio. The rotation transmission from the first output shaft 5c of the second power distributor 5 to the power output shaft 11 is achieved via gears 20, 15b or rotation transmission mechanisms 15, 14 of a speed change unit 10 at a plurality of stages of speed reduction ratio.

Abstract: The present invention provides a power transmitting apparatus that uses a small configuration to efficiently carry out various forms of propulsions such as a speed change propulsion and even an EV propulsion (electric propulsion) including a series type EV propulsion. The power transmitting apparatus includes a clutch 8 that connects and disconnects rotation transmissions between an output shaft 1a of an engine 1 and an input shaft 4r of one 4 of two power distributors 4 and 5 to which a rotational drive force is transmitted by the engine 1, a clutch 9 that connects and disconnects rotation transmissions between one of two output shafts 5c, 5c of the power distributor 5 and a power output shaft 12, and rotation regulating means 10 and 11 that properly inhibit rotation of the input shaft 4r of the power distributor 4 and rotation of the output shaft 5c of the power distributor 5.

Abstract: An angle detector 25 detects a rotor angle &thgr; of a DC brushless motor 1 using a current value Iu_s detected by a U-phase current sensor 23 and a current value Iw_s detected by a W-phase current sensor 24 when high-frequency voltages vu, vv, vw for detecting a rotor angle are applied by a high-frequency adding unit 21. The high-frequency adding unit 21 determines the high-frequency voltages vu, vv, vw so that the direction of rotation of the motor 1 and the direction of a revolving magnetic field generated by the high-frequency voltages vu, vv, vw will be opposite to each other. A three-phase/dq converter 26 converts the current values Iw_s, Iu_s into a detected d-axis current Id_s and a detected q-axis current Iq_s using the rotor angle &thgr; detected by the angle detector 25.

Abstract: An angle detector 25 sets a q-axis command current to a first magnetic pole detecting current Iq_p1 and a second magnetic pole detecting current Iq13p2, and performs a magnetic pole detecting process to calculate a first magnetic pole reference value A1 and a second magnetic pole reference value A2 (t2-t3, t4 -t5), and detect the orientation of the magnetic poles of a rotor 2 of a motor 1 based on the sign of the difference &Dgr;A (=A1-A2) between the first magnetic pole reference value Al and the second magnetic pole reference value A2.

Abstract: An oscillation circuit is provided with a positive feedback oscillation loop constructed by an amplifier, a SAW resonator with a prescribed resonance frequency, a phase-shifting circuit which outputs the phase of an input signal as an output signal with a prescribed shift and a tank circuit composed of an inductance element and a capacitive element, and an NTC thermistor with negative temperature characteristics is connected in parallel to the tank circuit. Moreover, a capacitive element with a capacity-temperature characteristic for correcting the quadratic frequency-temperature characteristic of the SAW resonator is used in the oscillation circuit as the oscillation element of the tank circuit.

Abstract: An oscillation circuit is provided including a differential amplifier having plural output terminals that provide output signals having different phases from each other, a SAW resonator, and a phase shift circuit, wherein the differential amplifier, SAW resonator, and phase shift circuit forming a positive feedback oscillation loop and a switch circuit being provided for selecting one of the output terminals of the differential amplifier to complete the positive feedback oscillation loop. The switch circuit selects one of the signals SQ1 and SQ2 and transmits it to the phase shift circuit. The phase shift circuit transmits output signals that result from a predetermined phase shift of input signals to the SAW resonator.

Abstract: By supplying a control voltage that corresponds to the phase difference between an output signal of a temperature-compensated crystal oscillator (TCXO 1) and a signal obtained by dividing an output signal of a voltage-controlled SAW oscillator (VCSO 4) using the SAW resonator to the VCSO 4, the frequency of the output signal of the VCSO 4 is controlled so as to be constant over a wide temperature range.

Abstract: A method of adjusting the temperature properties of piezoelectric devices and oscillation circuits which have a third-order function temperature property and the point of inflection of the third-order function temperature property outside the normal usage temperature range. The local maximum point or local minimum point temperature located in the normal temperature range is regarded as the peak temperature of the apparent second-order function temperature property, and the peak temperature is adjusted to the optimum value in the normal temperature range by rotating the temperature property around the point of inflection located outside the normal temperature range by adjusting the first-order coefficient.

Abstract: An inspection voltage imposer generates an inspection voltage by multiplying fundamental voltage string data in which a certain voltage output pattern where an average of output voltage levels in one period becomes 0 is set by data of a modulation signal whose value varies every period and impose the inspection voltage on a drive voltage of a motor. When the inspection voltage is imposed on the drive voltage of the motor, an angle detector detects the rotor angle of the motor based on the fundamental voltage string data, a variation of an inspection current and the data of the modulation signal in respective control cycles.

Abstract: A motor controller implements alternately a feedback control for d axis current and a feedback control for q axis current using an estimate value of a rotor angle in different control cycles. Then, the motor controller calculates a sine reference value which corresponds to a sine value of an angle which is twice a phase difference between an actual value and an estimate value of a rotor angle and a cosine reference value which corresponds to a cosine value of the angle which is twice the phase difference based on variations of the d axis actual current and q axis actual current and levels of d axis voltage and q axis voltage in a control cycle in which feedback controls are implemented for d axis current and q axis current and detects a rotor angle using the sine reference value and the cosine reference value so calculated.