Abstract: A pressure-compensated cutter assembly for a tunnel boring machine includes a shaft a cutter ring assembly rotatably mounted on the shaft, and first and second end retainers non-rotatably attached to the shaft. Rotary seal groups, immersed in lubricant, provide a moving seal between the rotating cutter ring assembly and the end retainers. A movable piston member is exposed to ambient pressures, and contacts the lubricant, such that increasing ambient pressure will increase the lubricant pressure, thereby keeping the pressure differential across the seal small. In one embodiment, the piston is a floating retainer portion. In another embodiment, the piston is an annular piston, and in another embodiment, the piston is a plurality of smaller pistons disposed in the first retainer.

Abstract: A pressure-compensated cutter assembly for a tunnel boring machine includes a shaft a cutter ring assembly rotatably mounted on the shaft, and first and second end retainers non-rotatably attached to the shaft. Rotary seal groups, immersed in lubricant, provide a moving seal between the rotating cutter ring assembly and the end retainers. A movable piston member is exposed to ambient pressures, and contacts the lubricant, such that increasing ambient pressure will increase the lubricant pressure, thereby keeping the pressure differential across the seal small. In one embodiment, the piston is a floating retainer portion. In another embodiment, the piston is an annular piston, and in another embodiment, the piston is a plurality of smaller pistons disposed in the first retainer.

Abstract: A tunnel excavating machine of high-speed construction capable of completely stopping invasion of water and allowing covering members to be assembled easily is provided. This tunnel excavating machine comprises: a cylindrical excavating machine main portion 1 provided with a cutter head 4 and fit to an external periphery of an existing segment S through a tail seal 23; a cylindrical excavating machine auxiliary portion 2 fit to the inside of the excavating machine main portion 1 movably in the back and forth directions and provided with an erector 25 for assembling the segments; a plurality of main propulsion jacks 22 disposed between the main portion 1 and the auxiliary portion 2; and a plurality of auxiliary propulsion jacks 22 mounted on the auxiliary portion 2 and capable of being retracted with respect to the segment S.

Abstract: A motor control system designed to monitor a failure in a multi-phase dc motor is provided. The motor control system includes an inverter which controls an operation of the motor, a failure detecting circuit which monitors the voltage appearing at one of terminals of armature windings of the motor every active time when a PWM signal is at an active level to turn on switching elements of the inverter and determines occurrence of the failure based on the monitored voltage, and a switching operation prohibiting circuit which prohibits one of the switching elements connected to the one of the terminals of the windings of the motor from being turned on, thereby avoiding additional damages of the motor control system.

Abstract: It is an object of the present invention to provide a tunnel excavating machine of high-speed construction type and an excavation method which is capable of stopping invasion of water completely and allows covering members to be assembled easily.

Abstract: A semiconductor device mount structure includes a heat dissipating member, a circuit board, a semiconductor device and a leaf spring member. The heat dissipating member has a mounting surface. The circuit board is opposed to the mounting surface of the heat dissipating member. The semiconductor device is mounted to the mounting surface of the heat dissipating member. The semiconductor device is electrically connected to the circuit board. The leaf spring member is arranged between the semiconductor device and the circuit board in such a manner that the leaf spring member biases the semiconductor device against the mounting surface of the heat dissipating member. The leaf spring member has a heat insulating material integrated on one side thereof which faces the circuit board.

Abstract: A semiconductor device mount structure includes a heat dissipating member, a circuit board, a semiconductor device and a leaf spring member. The heat dissipating member has a mounting surface. The circuit board is opposed to the mounting surface of the heat dissipating member. The semiconductor device is mounted to the mounting surface of the heat dissipating member. The semiconductor device is electrically connected to the circuit board. The leaf spring member is arranged between the semiconductor device and the circuit board in such a manner that the leaf spring member biases the semiconductor device against the mounting surface of the heat dissipating member. The leaf spring member has a heat insulating material integrated on one side thereof which faces the circuit board.

Abstract: A load control system includes a driving circuit for electrically controlling a blower motor, and a control circuit for generating a control signal for the motor. The driving circuit is directly connected to an electrical power source, and the control signal from the control circuit is input into the driving circuit through a signal input line. The control signal from the control circuit is a duty signal in which a duty ratio becomes 100% when the signal input line is ground short-circuited. In the load control system, a comparison circuit determines a ground short-circuited state of the signal input line when the duty ratio is increased to a value proximate to 100%, and the motor is automatically stopped based on output from the comparison circuit when the signal input line is ground short-circuited. Thus, the load control system can prevent full-load operation of the motor due to the ground short-circuit of the signal input line, even the driving circuit is directly connected to the electrical power source.

Abstract: A load drive control apparatus includes a drive control circuit for driving and controlling a load in response to a given drive condition. A power supply circuit operates for feeding drive electric power to the drive control circuit. The feed of the drive electric power to the drive control circuit by the power supply circuit is controlled in response to a control signal for drive and control of the load to implement a change between a normal mode of operation and a stand-by mode of operation in which consumed electric power is reduced.

Abstract: A magnetic detection device including a biasing magnet for generating a bias magnetic field directed to an object of detection having a magnetic material; a magnetoresistance effective element disposed at an inclination of about 45.degree. to the direction of the bias magnetic field to provide a change in resistance caused by the bias magnetic field in accordance with movement of the object of detection, so as to detect a change in state of the bias magnetic field via the change in resistance of the magnetoresistance effective element; and the biasing magnet having a hollow portion containing a holder for holding the magnetoresistance effective element in a position between a surface of the biasing magnet and the object of detection and close to the surface of the biasing element.