Abstract: A four-stroke engine includes a cylinder block, a cylinder head mounted on the cylinder block, multiple cooling fins formed on the cylinder block and the cylinder head, a combustion chamber and an intake port and exhaust port formed in the cylinder head and in communication with the combustion chamber. A cooling jacket is formed in the cylinder head only between a virtual object generated by the intake port or exhaust port being rotated about a cylinder axis. A mating surface of the cylinder head on the cylinder block.

Abstract: There is provided a wired circuit board assembly that prevents breakage of the flexing portion of a wired circuit board supported by a support frame. In a wired circuit board support sheet, a plurality of wired circuit boards include a base insulating layer, a conductor pattern, and a cover insulating layer which are formed on a support board are supported by a support frame in such a manner that they are arranged and aligned in mutually spaced relation. Each of the wired circuit boards has a flexing portion formed by removing the support board to obtain a flexing property. In addition, second connecting portions are provided in spanning relation between the flexing portion and the vertical frame parts of the support frame.

Abstract: A wired circuit board prevents a sealing resin filled in an electronic component mounting portion from overflowing and spreading to a different area other than the electronic component mounting portion. An electronic component placing area is provided in the electronic component mounting portion for the electronic component to be placed and terminals are located within the electronic component placing area and formed to extend continuously with the conductive wires. Also, a groove extending around the electronic component mounting portion to intersect with the conductive wires is formed in the insulating cover layer. Further, protrusions protruding in a direction of the conductive wires being extended in the groove are formed at an intersecting portion thereof with the conductive wires. This can reduce a tendency of the overly filled sealing resin to flow over the groove, thus preventing the spread of the sealing resin from the groove to the outside thereof.

Abstract: A clutch failure detector is provided for detecting failure of an automatic clutch system. The clutch failure detector can include a current value detector and a determination device. Upon turning ON a main switch, an operation to disengage and engage a clutch can be performed by a clutch actuator, and a totalized value of current supplied to a clutch actuator can be calculated for a specific period of time while the clutch is in the process of engaging in the operation to disengage and engage the clutch. The totalized value can be compared with a preset threshold, and if a difference between the totalized value and the threshold is equal to or greater than a given value, it is determined that an automatic clutch system has a failure.

Abstract: A wired-circuit-board assembly sheet is provided having removable portions that are easily removable without any generation of metal powder. The wired-circuit-board assembly sheet comprises a plurality of suspension boards with circuits, distinguishing marks for distinguishing defectiveness of the suspension boards with circuits, and a supporting sheet for supporting the suspension boards with circuits and the distinguishing marks, wherein openings are formed in the supporting sheet, and removable portions which are to be removed when the suspension boards with circuits are judged defective are located in the openings and also supported by the supporting sheet via joint portions formed of resin.

Abstract: A lubrication system for an engine includes an oil tank, a crankshaft, a crankcase for housing the crankshaft. An oil sump formed at a bottom of the crankcase collecting lubricant for circulated moving parts to be lubricated, and an oil pump for returning the lubricant collected in the oil sump to the oil tank are also provided. The oil sump and an oil suction port are provided, respectively, on one side and the another side of a normal plane including an axis of the crankshaft.

Abstract: The present invention provides a bearing system that can reduce the relative velocity between a bearing member and a rotation shaft and a rotating member to decrease a load on the bearing member although the rotation shaft and the rotating member rotate in opposite directions with the bearing member therebetween. A bearing system of the present invention includes a case and a rotation shaft supported by the case. A rotating member is disposed coaxially outside the rotation shaft and rotates in the direction opposite to that of the rotation shaft. A housing is interposed between the rotation shaft and the rotating member and is fixed to the case. A bearing member that rotatably supports the rotating member is interposed between the housing and the rotating member.

Abstract: A wired circuit board prevents a sealing resin filled in an electronic component mounting portion from overflowing and spreading to a different area other than the electronic component mounting portion. An electronic component placing area is provided in the electronic component mounting portion for the electronic component to be placed and terminals are located within the electronic component placing area and formed to extend continuously with the conductive wires. Also, a groove extending around the electronic component mounting portion to intersect with the conductive wires is formed in the insulating cover layer. Further, protrusions protruding in a direction of the conductive wires being extended in the groove are formed at an intersecting portion thereof with the conductive wires. This can reduce a tendency of the overly filled sealing resin to flow over the groove, thus preventing the spread of the sealing resin from the groove to the outside thereof.

Abstract: There is provided a wired circuit board assembly which allows effective prevention of the breakage of the flexing portion of a wired circuit board supported by a support frame. In a wired circuit board support sheet (1), a plurality of wired circuit boards (2) each composed of a base insulating layer (5), a conductor pattern (6), and a cover insulating layer (7) which are formed on a support board (4) are supported by a support frame (3) in such a manner that they are arranged and aligned in mutually spaced relation. Each of the wired circuit board (2) has a flexing portion (20) formed by removing the support board (4) to obtain a flexing property. In addition, second connecting portions (19) are provided in spanning relation between the flexing portion (20) and the vertical frame parts (16) of the support frame (3). The arrangement allows effective prevention of the breakage of the flexing portion (20) of each of the wired circuit boards (2) supported by the support frame (3).

Abstract: A wired circuit board can control characteristic impedance at connection points between wires of a suspension board with circuit and terminal portions of the wired circuit board connected thereto with a simple structure, to improve signal transmission efficiency even for fine pitch wiring or for high frequency signals. The wired circuit board includes a relay flexible wiring circuit board formed by a first wired circuit board including a first metal substrate, a first insulating base layer, a first conductor layer and a first insulating cover layer which is substantially identical in layer structure with the suspension board with circuit and a second wired circuit board connected with the first wired circuit board for connecting with a control circuit board. Since the suspension board with circuit and the first wired circuit board are rendered substantially identical in layer structure, both characteristic impedances at these connection points can be matched.

Abstract: A lubrication device for a dry-sump, four-stroke engine includes a crankcase having a divider wall interposed between a crank chamber and a separate adjoining chamber. A crankshaft is housed in the crank chamber and is driven by reciprocating movement of pistons. A crank web faces the divider wall, which has a through hole for connecting the crank chamber with the separate chamber, and is opened by the crank web when the piston moves from a top dead center position toward a bottom dead center position, and is closed when the piston moves from the bottom dead center toward the top dead center position. A return hole connects the crank chamber and the separate chamber, for returning lubricant oil that flowed through the through hole into the separate chamber from the crank chamber, back to the crank chamber by utilizing pressure fluctuations within the crank chamber.

Abstract: A balancer structure for an engine includes a first balancer shaft, a second balancer shaft, a crankshaft having a crank gear and balancer gears on the first and second balancer shafts provided parallel to the crankshaft and driven for rotation by the crank gear. The first balancer shaft is provided on one side of a normal plane including an axis of the crankshaft, and the second balancer shaft is provided on another side. On the second balancer shaft is provided a counter gear for transmitting a rotation of the crankshaft to a main shaft of a transmission mechanism.

Abstract: A balancer apparatus of an engine includes a crank case, a crankshaft supported by the crank case and including a crank web having a pin connecting portion connected with a crank pin and a counter weight portion, a balancer shaft arranged in parallel with the crankshaft and rotated in cooperation with the crankshaft and a balance weight provided on the balancer shaft and rotated integrally with the balancer shaft. The balancer shaft is installed at a position of overlapping the crank web when viewed from an axial direction of the crankshaft.

Abstract: A balancer apparatus of an engine includes a crank case, a crankshaft supported by the crank case and including a crank web having a pin connecting portion connected with a crank pin and a counter weight portion, a balancer shaft arranged in parallel with the crankshaft and rotated in cooperation with the crankshaft and a balance weight provided on the balancer shaft and rotated integrally with the balancer shaft. The balancer shaft is installed at a position of overlapping the crank web when viewed from an axial direction of the crankshaft.

Abstract: A lubrication device for a dry-sump, four-stroke engine includes a crankcase having a divider wall, a crank chamber and a separate adjoining chamber with the divider wall interposed in between the crank chamber and separate chamber. A crankshaft is housed in the crank chamber and is driven by the reciprocating movement of the pistons. A crank web faces the divider wall, and the divider wall has a through hole for connecting the crank chamber with the separate chamber, and is opened by the crank web when the piston moves from a top dead center position toward a bottom dead center position, and is closed by the crank web when the piston moves from the bottom dead center toward the top dead center position. A return hole connects the crank chamber and the separate chamber, for returning lubricant oil that flowed by way of the through hole into the separate chamber from the crank chamber, back to the crank chamber by utilizing pressure fluctuations within the crank chamber.

Abstract: A lubrication system for an engine includes an oil tank, a crankshaft, a crankcase for housing the crankshaft. An oil sump formed at a bottom of the crankcase collecting lubricant for circulated moving parts to be lubricated, and an oil pump for returning the lubricant collected in the oil sump to the oil tank are also provided. The oil sump and an oil suction port are provided, respectively, on one side and the another side of a normal plane including an axis of the crankshaft.

Abstract: A four-stroke engine includes a cylinder block, a cylinder head mounted on the cylinder block, multiple cooling fins formed on the cylinder block and the cylinder head, a combustion chamber and an intake port and exhaust port formed in the cylinder head and in communication with the combustion chamber. A cooling jacket is formed in the cylinder head only between a virtual object generated by the intake port or exhaust port being rotated about a cylinder axis. A mating surface of the cylinder head on the cylinder block.

Abstract: A balancer structure for an engine includes a first balancer shaft, a second balancer shaft, a crankshaft having a crank gear and balancer gears on the first and second balancer shafts provided parallel to the crankshaft and driven for rotation by the crank gear. The first balancer shaft is provided on one side of a normal plane including an axis of the crankshaft, and the second balancer shaft is provided on another side. On the second balancer shaft is provided a counter gear for transmitting a rotation of the crankshaft to a main shaft of a transmission mechanism.

Abstract: A wired circuit board that can control characteristic impedance at connection points between wires of a suspension board with circuit and terminal portions of the wired circuit board connected thereto with a simple structure, to improve signal transmission efficiency even for fine pitch wiring or for high frequency signal. To provide this wired circuit board, a relay flexible wiring circuit board 1 is formed by a first wired circuit board 14 comprising a first metal substrate 16, a first insulating base layer 17, a first conductor layer 18 and a first insulating cover layer 19 which is substantially identical in layer structure with the suspension board with circuit 3 and a second wired circuit board 15 connected with the first wired circuit board 14 for connecting with a control circuit board 4.

Abstract: When a digitally compressed and encoded video data stream contains line data, a line data detection circuit in a DVD decoder detects the presence of that line data, and informs a CPU of it using an interrupt signal. When the CPU receives the line data from a data register in the DVD decoder, it converts it into character information and writes the information in an image memory, or converts the line data into an on-screen display command for controlling the OSD function of the DVD decoder and issues that command.