Abstract: A device is provided with a PWM signal generating circuit, a gate driver and a transmission line connecting them. The transmission line transmits a PWM signal output from the PWM generator as an input signal for the gate driver. A noise suppression member is provided to at least a part of a periphery of the transmission line. The noise suppression member has a structure that magnetic powder is dispersed in a binder and has an imaginary part ?? of a complex magnetic permeability that is greater than or equal to 5 and smaller than or equal to 30 in a range of 500 MHz to 3 GHz. The noise suppression member has a thickness t greater than or equal to 20 ?m. The noise suppression member is disposed apart from a conducting wire of the transmission line by a distance greater than 0.05 mm or smaller than or equal to 5 mm.

Abstract: A device is provided with a PWM signal generating circuit, a gate driver and a transmission line connecting them. The transmission line transmits a PWM signal output from the PWM generator as an input signal for the gate driver. A noise suppression member is provided to at least a part of a periphery of the transmission line. The noise suppression member has a structure that magnetic powder is dispersed in a binder and has an imaginary part ?? of a complex magnetic permeability that is greater than or equal to 5 and smaller than or equal to 30 in a range of 500 MHz to 3 GHz. The noise suppression member has a thickness t greater than or equal to 20 ?m. The noise suppression member is disposed apart from a conducting wire of the transmission line by a distance greater than 0.05 mm or smaller than or equal to 5 mm.

Abstract: A communication device includes an antenna unit, a switch unit, a matching unit which is connected between the antenna and switch units, a communication unit which is connected to the switch unit, and a switch control unit. When the switch unit is in a conductive state, the matching unit matches a first impedance occurring if the antenna unit is seen from the matching unit and a second impedance occurring if the switch unit is seen from the matching unit. The switch control unit controls the switch unit so that the switch unit is set to the conductive state when the communication unit communicates via the antenna unit, and so that the switch unit is set to an interrupted state when the communication unit is to be protected from overvoltage. The switch control unit and switch unit are semiconductors formed under a first process rule and second process rule, respectively.

Abstract: A four-stroke engine for a working machine with a rod is provided, where a tool is attached to one end of the rod in a longitudinal direction and the four-stroke engine is fixed to the other end of the rod in use. The four-stroke engine includes: an oil circulation pathway; and a gas-liquid separating chamber configured to separate oil from blowby gas. The gas-liquid separating chamber includes: an inflow part into which the blowby gas is introduced from the oil circulation pathway; oil discharge parts configured to flow the oil separated from the blowby gas back to the oil circulation pathway; and a blowby gas discharge part configured to discharge the blowby gas not containing oil mist from the gas-liquid separating chamber and supplies the blowby gas to an intake passageway to a combustion chamber.

Abstract: A communication device includes an antenna unit, a switch unit, a matching unit which is connected between the antenna and switch units, a communication unit which is connected to the switch unit, and a switch control unit. When the switch unit is in a conductive state, the matching unit matches a first impedance occurring if the antenna unit is seen from the matching unit and a second impedance occurring if the switch unit is seen from the matching unit. The switch control unit controls the switch unit so that the switch unit is set to the conductive state when the communication unit communicates via the antenna unit, and so that the switch unit is set to an interrupted state when the communication unit is to be protected from overvoltage. The switch control unit and switch unit are semiconductors formed under a first process rule and second process rule, respectively.

Abstract: A communication apparatus includes: a communication antenna, a communication unit which can transmit and receive signals, a switch connected between the communication antenna and the communication unit and composed of a semiconductor switch, a switch control unit, and a high-voltage output means. The switch, when receiving a connection command signal causes the communication unit to be electrically connected with the communication antenna, and when not receiving the signal cuts them off. The switch control unit outputs the signal to the switch under prescribed conditions, and stops the signal when overvoltage applied to the communication unit is detected. The high-voltage output means, connected between the switch control unit and the switch, sets voltage of the signal received from the switch control unit to a voltage at which the communication unit in a transmitting mode would not be cut off from the communication antenna, and outputs the voltage to the switch.

Abstract: A lubrication apparatus for a four-stroke engine includes an oil tank, a supply passageway having an opening to supply oil mist from the oil tank to driving parts, the opening being provided in the oil tank. A partition is provided between the opening and a side wall of the oil tank, the partition being formed by partition plate members so as to divide an inside of the oil tank into an inner area and an outer area. The inner area includes the opening, and the outer area is defined between the inner area and the side wall. Oil can freely move between the inner area and the outer area, and the opening is placed in a position above a surface of the oil accumulated in the oil tank even when the four-stroke engine is tilted in every direction.

Abstract: A lubrication apparatus for a four-stroke engine that prevents lubrication failure from occurring around the crankshaft and reliably prevents oil from remaining in a valve operating chamber includes: an intake part positioned below the level of an oil A in an oil reservoir even if the oil reservoir is tilted and the level of the oil A changes; an oil feeding passageway that sucks up the oil A from the intake part and supplies the oil A to the crank chamber; and an direct passageway that allows communication between a valve operating chamber and a crank chamber when a negative pressure is created in the crank chamber. Open end parts of the oil feeding passageway and the direct passageway which are open in the crank chamber are provided to open as the piston moves from a position near the top dead center to the top dead center.

Abstract: A lubrication system for a portable four-stroke engine includes an opening end of the breather passage is disposed at substantially a center of a valve-operating chamber, and the valve-operating chamber is formed by attaching a valve-operating chamber cover. An inner cover is attached to an inner surface of the valve-operating chamber cover so as to be provided along and in contact with the inner surface of the valve-operating chamber cover. A suction passage is formed as a gap between the circumferential edge of the top plate portion and the inner cover. Three or more suction tubes that are in communication with the suction passage are provided in the inner cover, each of the suction tubes having an opening end. At least one of the opening ends of the suction tubes is provided lower than the opening end of the breather passage in an attitude of the engine during use.

Abstract: A lubrication system for a four cycle engine that lubricates the valve mechanism with the oil mist of the concentration, lowered by the liquefying means. The lubrication system has an oil feeding passage for connecting an oil reservoir with the crank chamber and sending the oil retained in liquid form in the oil reservoir to the crank chamber under a negative pressure of the crank chamber, a communication passage for connecting the crank chamber with the oil reservoir and sending oil mist generated in the crank chamber to the oil reservoir when under a positive pressure of the crank chamber, liquefying means in the oil reservoir for liquefying the oil mist sent from the communication passage to the oil reservoir to decrease the concentration of the oil mist, and a supply passage for supplying the oil mist from the oil reservoir to the valve operating chamber through the liquefying means.

Abstract: A lubrication apparatus for a four-stroke engine includes: an oil tank; a supply passageway having an opening to supply oil mist from the oil tank to driving parts, the opening being formed in the oil tank; and a partition provided between the opening and a side wall of the oil tank, the partition being formed by partition plate members to divide an inside of the oil tank into an inner area and an outer area, the inner area including the opening, and the outer area being defined between the inner area and the side wall. Oil can freely move between the inner area and the outer area, and the opening is placed in a position above a surface of the oil accumulated in the oil tank even when the four-stroke engine is tilted in every direction.

Abstract: A four-stroke engine for a working machine with a rod is provided, where a tool is attached to one end of the rod in a longitudinal direction and the four-stroke engine is fixed to the other end of the rod in use. The four-stroke engine includes: an oil circulation pathway; and a gas-liquid separating chamber configured to separate oil from blowby gas. The gas-liquid separating chamber includes: an inflow part into which the blowby gas is introduced from the oil circulation pathway; oil discharge parts configured to flow the oil separated from the blowby gas back to the oil circulation pathway; and a blowby gas discharge part configured to discharge the blowby gas not containing oil mist from the gas-liquid separating chamber and supplies the blowby gas to an intake passageway to a combustion chamber.

Abstract: A lubrication apparatus for a four-stroke engine (1) is provided that prevents lubrication failure from occurring around the crankshaft and reliably prevents oil from remaining in a valve operating chamber (30). The lubrication apparatus for the four-stroke engine (1) includes: an intake part (55) positioned below the level of an oil A in an oil reservoir (7) even if the oil reservoir (7) is tilted and the level of the oil A changes; an oil feeding passageway (54) that sucks up the oil A from the intake part (55) and supplies the oil A to the crank chamber (5a); and an direct passageway (47) that allows communication between a valve operating chamber (30) and a crank chamber (5a) when a negative pressure is created in the crank chamber (5a). Open end parts (47a, 54a) of the oil feeding passageway (54) and the direct passageway (47) which are open in the crank chamber (5a) are provided to open as the piston (13) moves from a position near the top dead center to the top dead center.

Abstract: A lubrication system for a portable four-stroke engine includes an opening end of the breather passage is disposed at substantially a center of a valve-operating chamber, and the valve-operating chamber is formed by attaching a valve-operating chamber cover. An inner cover is attached to an inner surface of the valve-operating chamber cover so as to be provided along and in contact with the inner surface of the valve-operating chamber cover. A suction passage is formed as a gap between the circumferential edge of the top plate portion and the inner cover. Three or more suction tubes that are in communication with the suction passage are provided in the inner cover, each of the suction tubes having an opening end. At least one of the opening ends of the suction tubes is provided lower than the opening end of the breather passage in an attitude of the engine during use.

Abstract: A lubrication system for a four cycle engine lubricates the valve mechanism with the oil mist of the concentration lowered by the liquefying means. The lubrication system has an oil feeding passage for connecting an oil reservoir and the crank chamber and sending the oil retained in liquid form in the oil reservoir to the crank chamber under a negative pressure of the crank chamber, a communication passage for connecting the crank chamber and the oil reservoir and sending oil mist generated in the crank chamber to the oil reservoir when under a positive pressure of the crank chamber, liquefying means in the oil reservoir for liquefying the oil mist sent from the communication passage to the oil reservoir to decrease the concentration of the oil mist, and a supply passage for supplying the oil mist from the oil reservoir to the valve operating chamber through the liquefying means.

Abstract: A centrifugal compressor for use in turbo-refrigerators, for example, has a motor casing frame section in which a drive motor is accomodated and a gear casing frame section in which a multiplying gear mechanism is accomodated. The multiplying gear mechanism is connected at its input side with the drive motor and at its output side with an impeller. The mechanism has a first shaft including a rotor shaft of the drive motor and a gear shaft carrying a multiplying gear and separably connected directly with the rotor shaft, a second shaft mounting the impeller and having a pinion meshing with the speed multiplying gear, and bearings mounted on bearing casing frame sections for supporting the first and second shafts at their opposed ends, respectively. The motor casing frame section, gear casing frame section and bearing casing frame section are integrally formed as a unitary body.

Abstract: A centrifugal compressor for use in turbo-refrigerators, for example, has a motor casing frame section in which a drive motor is accomodated and a gear casing frame section in which a multiplying gear mechanism is accomodated. The multiplying gear mechanism is connected at its input side with the drive motor and at its output side with an impeller. The mechanism has a first shaft including a rotor shaft of the drive motor and a gear shaft carrying a multiplying gear and separably connected directly with the rotor shaft, a second shaft mounting the impeller and having a pinion meshing with the speed multiplying gear, and bearings mounted on bearing casing frame sections for supporting the first and second shafts at their opposed ends, respectively. The motor casing frame section, gear casing frame section and bearing casing frame section are integrally formed as a unitary body.