Abstract: To provide a plastic optical fiber using amorphous fluorinated polymers whereby transmission loss and bending loss are low, no cracking takes place during stretching, and a wide range of molding conditions is acceptable.

Abstract: To provide a plastic optical fiber using amorphous fluorinated polymers whereby transmission loss and bending loss are low, no cracking takes place during stretching, and a wide range of molding conditions is acceptable.

Abstract: Disclosed is a document conveying apparatus including: a reading unit which read image information on a surface of a document; a driving-side discharge unit which conveys the document in a first direction in contact with the first surface, and discharges at least a part of the document; a driven-side discharge unit which receives transmission of a rotative force from the driving-side discharge unit, when being in contact with the driving-side discharge unit; a specific-direction conveying unit which conveys the document in an opposite direction to the first direction; a pressing force applying unit which applies a force in a third direction to the driven-side discharge unit so as to be in contact with the driving-side discharge unit; and a movement control unit which moves the driven-side discharge unit in an opposite direction to the third direction, when the document is in contact with the driven-side discharge unit.

Abstract: Disclosed is a document conveying apparatus including: a reading unit which read image information on a surface of a document; a driving-side discharge unit which conveys the document in a first direction in contact with the first surface, and discharges at least a part of the document; a driven-side discharge unit which receives transmission of a rotative force from the driving-side discharge unit, when being in contact with the driving-side discharge unit; a specific-direction conveying unit which conveys the document in an opposite direction to the first direction; a pressing force applying unit which applies a force in a third direction to the driven-side discharge unit so as to be in contact with the driving-side discharge unit; and a movement control unit which moves the driven-side discharge unit in an opposite direction to the third direction, when the document is in contact with the driven-side discharge unit.

Abstract: The present invention is directed to the provision of a servomotor driving apparatus that feeds energy stored in a power storage part connected with a DC link that connects a rectifier circuit with an inverter circuit so that the energy stored in the power storage part can be reduced. A motor driving apparatus (1) includes: a step-up type DC/DC converter circuit (11) for boosting voltage appearing at an output of the power storage part (C1) connected with a DC link; and a DC/AC conversion circuit (12, 14) for converting the boosted DC electric power into AC electric power and feeding it to an electric power source.

Abstract: While the motor drive amplifier is not operating, electromagnetic switch contacts are held closed for a predetermined period of time, three-phase power is rectified by a rectifier circuit and a smoothing capacitor is charged. Then, the smoothing capacitor is discharged through a discharging resistor and, when a predetermined voltage is reached, a contact is closed, with the result that a closed circuit is formed by the smoothing capacitor, a detection resistor, a motor coil, motor insulation resistance, and ground. A voltage generating across the detection resistor due to leakage current is detected and compared with a reference value. If the detected voltage exceeds the reference value, an insulation degradation signal is delivered.

Abstract: The present invention is directed to the provision of a servomotor driving apparatus that feeds energy stored in a power storage part connected with a DC link that connects a rectifier circuit with an inverter circuit so that the energy stored in the power storage part can be reduced. A motor driving apparatus (1) includes: a step-up type DC/DC converter circuit (11) for boosting voltage appearing at an output of the power storage part (C1) connected with a DC link; and a DC/AC conversion circuit (12, 14) for converting the boosted DC electric power into AC electric power and feeding it to an electric power source.

Abstract: While the motor drive amplifier is not operating, electromagnetic switch contacts are held closed for a predetermined period of time, three-phase power is rectified by a rectifier circuit and a smoothing capacitor is charged. Then, the smoothing capacitor is discharged through a discharging resistor and, when a predetermined voltage is reached, a contact is closed, with the result that a closed circuit is formed by the smoothing capacitor, a detection resistor, a motor coil, motor insulation resistance, and ground. A voltage generating across the detection resistor due to leakage current is detected and compared with a reference value. If the detected voltage exceeds the reference value, an insulation degradation signal is delivered.

Abstract: A motor driving apparatus capable of predicting motor insulation deterioration at low costs. When a motor drive amplifier is not in operation, a relay contact K1 is turned on or closed to form a closed circuit of a motor housing grounded at G2, a motor coil, resistors R1, R2, the relay contact K1, diodes D4, D5, D6, an AC power source, and a ground point G1. A voltage of the AC power source to ground is applied to the closed circuit. When the insulation resistance of the motor is high, a small current flows through the closed circuit, so that potential difference across the resistor R1 is small. If the motor insulation is deteriorated, a leakage current increases. If potential difference across the resistor R1 exceeds a reference voltage determined by a Zener diode, an output signal is output from a comparator, a signal is output from a photocoupler, and the decrease in insulation resistance is indicated on an indicator of a control unit.

Abstract: A motor drive unit used in controlling an AC motor which drives the spindle or feed shaft of a machine tool is suitable for automatic assembly in which a plurality of electrical components are mounted and wired. In accordance with the motor drive unit of the invention, an upper frame (2) supporting a printed circuit board (1) having electrical circuitry which employs control semiconductors, and a lower frame (4) for mounting a heat radiating device (5), which mounts a rectifier or the like, as well as a power resistor (6), are constructed of synthetic resin. A power board (3) on which power circuit components are connected by soldering is sandwiched between the two frames (2), (4) and has the components on the heat radiating device (5) and the power resistor (6) mounted and connected thereto by screws. The two frames (2), (4) are fastened together by screws (25).

Abstract: A connecting terminal for connecting an electronic component to a printed circuit board includes a rectangular metal plate and a leg provided at each of four corners thereof. The approximate center of the metal plate is provided with a screw hole through which a screw is passed that is screwed into a terminal of a screw terminal-type electronic component. The legs of the connecting terminal, which are passed through pin holes provided in the printed circuit board, are soldered to an electrical circuit and thereby fixed to the circuit board. A screw which is screwed into the terminal of the screw terminal-type electronic component is passed through the screw hole of the connecting terminal. When the screw is tightened, the electronic component is secured to the printed circuit board.

Abstract: A switching regulator comprising a first diode inserted in series with and in a forward direction to a primary winding of the main power transformer, at least one subsidiary power transformer having a primary winding connected in parallel with the primary winding of the main power transformer, and a second diode inserted in series with and in a forward direction to a primary winding of the at least one subsidiary power transformer, which uses one switching control circuit and one switching means and applies chopped voltages to many transformers simultaneously, and generates many mutually insulated DC power sources, which can be small in size and have simple printed circuits.

Abstract: A position loop gain control method for deciding the gain of a digital-to-analog converter (301), which constitutes an orientation controller, in such a manner that the gain of a position loop assumes a set value K.sub.p, the position loop being part of a position control feedback system comprising a velocity control circuit (101c), a spindle motor (102), a position coder (104), an orientation controller (101e) and a changeover switch (101b), which method has steps of rotating the spindle motor at a predetermined velocity N.sub.b, measuring a deceleration time T.sub.f taken to achieve deceleration from the velocity N.sub.b down to a velocity of zero, and deciding a gain K.sub.DA of the digital-to-analog converter by using the set value K.sub.p, predetermined velocity Nb, deceleration time T.sub.f, and a distance D from a changeover point, at which there is a transition from velocity control to position control at a time when spindle orientation control is applied, to a prescribed orientation.

Abstract: A position control apparatus has a variable gain-type velocity amplifier (115) provided within a servo control circuit, and a low velocity sensing circuit (114) for sensing a predetermined low velocity of a motor (100) immediately before the motor is stopped. When the rotational velocity of the motor (100) drops to the predetermined low velocity immediately before stoppage during orientation control, the velocity amplifier is changed over in response to a signal from the gain of the low velocity sensing circuit (114), thereby raising servo loop gain.

Abstract: A speed detecting apparatus having a detector (101) for generating two sine-wave signals (PA, PB) which are .pi./2 out of phase with each other and have a frequency proportional to the speed of rotation of a motor so that actual-speed voltages (V.sub.L, V.sub.H) can be produced which are proportional to the speed of rotation of the motor. The speed detecting apparatus includes a quadrupling circuit and a frequency-to-voltage converter 107. Also included is a first speed generator for generating the actual-speed voltage (V.sub.H) in a high-speed range and a second speed generator which includes a four-phase rectangular signal generating circuit (106), a differentiating circuit (109), and a synchronous rectifier circuit (110) for producing the actual-speed voltage (V.sub.L) in a low-speed range. The voltages generated by the first and second speed generators are selectively issued as an output depending on whether the motor rotates at a high speed or a low speed.

Abstract: Disclosed is an induction motor drive apparatus which produces three-phase current commands using a speed error (ER) between a speed command and an actual speed (n) for driving an induction motor (10) on the basis of the current commands. The induction motor drive apparatus receives the speed error (ER) and the actual speed (n) as input signals and generates, through digital processing, a first phase sinusoidal signal and a second phase sinusoidal signal shifted by 2.pi./3 from the first phase sinusoidal signal. The first and second sinusoidal signals are used for generating a phase current (i.sub.w) in a first and second phase currents (i.sub.u, i.sub.v) which are in turn used to generate a third phase current (i.sub.w) such that the first, second and third phase current commands will have a sum equal to zero.

Abstract: During operation of a machine tool, a motor 14 driving a spindle 17 holding a tool 18 is operated at a commanded speed by a speed control system in accordance with a speed command signal VCMD with the feedback of an actual speed signal TSA. As a stopping command ORCM is issued for stopping the spindle, the spindle is decelerated to a predetermined speed in response to a reference signal output from a constant voltage generating circuit 33. After the deceleration of the spindle to the predetermined speed, as the rotational position of the spindle comes into a region within 180.degree. from a predetermined position, a position offset signal PS', which smoothly crosses the zero level at the position at which the spindle is to be stopped, and which is generated from two signals e.sub.1 and e.sub.2 from a resolver connected to the spindle.

Abstract: A speed control circuit and position control circuit are connected to a spindle drive motor in a machine tool or the like in order to drive the spindle at a predetermined speed and stop the spindle at a predetermined angular position. When an orientation command is issued while the spindle is being rotated at the predetermined speed by a speed control loop, a speed command signal from a speed command circuit is interrupted, the speed reduced to zero, and an initially set voltage is then employed as a speed command to rotate the spindle by a predetermined amount. Next, a integral value of the actual spindle speed is employed as the speed command to further rotate the spindle by a predetermined amount. When this has been accomplished, a constant bias voltage of a low level replaces the speed command, thereby to rotate the spindle still further by a predetermined amount until a specified portion of the spindle approaches extremely close to the predetermined angular position.

Abstract: A control circuit for driving an induction motor wherein an AC voltage is converted into a direct current by a rectifying circuit and the direct current is converted into a signal having a variable voltage and frequency by a transistor inverter connected in parallel with a smoothing capacitor, and a regenerative circuit is connected in parallel with the inverter, and a circuit is provided for comparing the terminal voltage V.sub.C of the smoothing capacitor and a reference voltage V.sub.r when braking is to take place is disclosed. When condition V.sub.C .gtoreq.V.sub.r exists, the transistor inverter is disabled but the regenerative circuit is allowed to operate; when the condition V.sub.C <V.sub.r exists, the transistor inverter is operated in the regenerative braking mode.

Abstract: A system for stopping a spindle, which is provided in a machine tool, in such a manner that a specified point on the spindle is stopped at a predetermined rotational position. The system includes device for detecting the direction of spindle rotation. When the spindle arrives at a region where it is to be controlled in order to stop at the predetermined rotational position, a position deviation signal is applied as the input signal of a speed control loop for controlling the rotation of the spindle. This signal turns the specified point on the spindle to the predetermined rotational position, in the same direction in which the spindle is rotating, on the basis of the direction signal from the detecting means. That is, the specified point on the spindle is rotated to the predetermined rotational position in a direction which is the same as the direction of rotation during tool operation.