Abstract: A gear pair includes a first gear and a second gear that are engaged and paired with each other, wherein the arithmetic average roughness Ra of the tooth surface of the first gear is less than 0.10, and the arithmetic average roughness Ra of the tooth surface of the second gear is equal to or greater than 0.15. An improvement of the transmission efficiency is achieved due to the improved composite roughness of the gear pair. Accordingly, both of the improvement of the transmission efficiency of the gears and an improvement of the pitting fatigue life are achieved at low cost.

Abstract: A gap adjustment member includes a main body and an outward protrusion. The main body portion has a diameter less than or equal to the diameter of a mounting hole. The outward protrusion protrudes outwardly on an outer perimeter surface of the main body portion, the number of the protrusions being less than or equal to the number of recessed grooves. A diameter of a circumscribing circle, which circumscribes the main body portion and passes a projecting end of the protrusion, and a crossing point, in which a line that passes the projecting end and a center of the main body portion intersects the outer perimeter surface of the main body portion, and which is a crossing point on the opposite side of the projecting end, is configured to be greater than the diameter of the mounting hole and less than or equal to the diameter of an annular groove.

Abstract: A transmission includes a fork mechanism in which a plurality of fork rods to which a plurality of shift forks are connected are each attached to a pedestal so as to be moveable in an axial direction. An assembly guide portion is disposed on the pedestal and a guide pin is erected on a clutch housing. As a result, even in cases where an input shaft and a main shaft, on which driving and driven gears and synchro devices are assembled, are assembled on the clutch housing in a state that the driving and driven gears are engaged and, thereafter the fork mechanism is assembled on this clutch housing, the assembly of the fork mechanism on the clutch housing can be easily performed.

Abstract: A cooling pipe for an internal combustion engine includes with a resin-made water outlet for forming a circulation path for circulating a coolant for cooling an engine body, and an attachment part for retaining a water temperature sensor for sensing the temperature of the coolant flowing through the water outlet, the attachment part being attached to the water outlet, a portion of the attachment part being in contact with the engine body, and the attachment part formed from a material whereby heat from the engine body is transmitted.

Abstract: A transmission device includes an output shaft, first and second input shafts, a first gear mechanism, a selective fixing device and a connecting and disconnecting device. The second input shaft is coaxially arranged on an outside periphery of the first input shaft. The first gear mechanism couples the first input shaft and the output shaft with a first gear ratio. The first gear mechanism includes an idle gear mounted on one of the first input shaft and the output shaft. The selective fixing device selectively fixes the idle gear to one of the first input shaft and the output shaft. The second gear mechanism couples the second input shaft and the output shaft with a second gear ratio. The connecting and disconnecting device selectively connects and disconnects the second input shaft to the rotating shaft.

Abstract: A gear pair includes a first gear and a second gear that are engaged and paired with each other, wherein the arithmetic average roughness Ra of the tooth surface of the first gear is less than 0.10, and the arithmetic average roughness Ra of the tooth surface of the second gear is equal to or greater than 0.15. An improvement of the transmission efficiency is achieved due to the improved composite roughness of the gear pair. Accordingly, both of the improvement of the transmission efficiency of the gears and an improvement of the pitting fatigue life are achieved at low cost.

Abstract: A mold apparatus for casting a cylinder block having a cast-in cylinder liner by installing the cylinder liner inside a cavity and pouring a melt into the cavity, the mold apparatus includes a first mold and a bore pin. The first mold defines a deck surface of the cylinder block. The bore pin is in the first mold so as to hold the cylinder liner inside the cavity when the mold is closed. The bore pin is configured to hold the cylinder liner interposed by a gap, and the gap is arranged so as to enable gas produced during the cast-molding to be discharged therethrough.

Abstract: A clutch device is configured to switch between a first clutch and a second clutch. The clutch device includes a fixed sleeve having a first male thread. The fixed sleeve is coaxially arranged around an exterior of a second input shaft. A first slider has a first internal female thread and a second external male thread. The first slider is arranged externally around the fixed sleeve. The second slider has a second internal female thread. The second slider is arranged around the exterior of the first slider to rotate and move in an axial direction. A first release bearing member is interposed between a member on the first clutch side and the second slider. A second release bearing member is interposed between a member on the side of the second clutch and the first slider. A first motor rotates the first slider. A second motor rotates the second slider.

Abstract: A three cylinder engine includes a vibration alleviation unit for alleviating vibrations in a vehicle. The vibration alleviation unit is disposed at least one of upon the crankshaft and upon a part that operates in unison with the crankshaft. The three cylinder is supported by engine mounts that are positioned upon at least both ends of the engine in the direction of the crankshaft axis. Given that KV and KH represent spring constants of one of the engine mounts in the pitch and yaw directions of the crankshaft, MV and MH represent components of a primary couple that occurs in the three cylinder engine in the pitch and yaw directions, and MV0 represents the sum of MV and MH, then spring constants of the engine mounts are set such that KV >KH and the vibration alleviation unit is set so as to satisfy the condition 0 <MV/MV0 <0.5.

Abstract: An upper oil pan of an engine includes a flange with an oil pan abutment surface that is fixedly coupled to a flange formed on a cylinder block. The oil pan abutment surface comprises a flat portion that is substantially parallel to a cylinder block abutment surface of the cylinder block, a slanted portion that is slanted with respect to the flat portion, and a vertical wall portion connecting the flat portion and the slanted portion. The vertical wall portion is formed substantially perpendicular to the flat portion. The cylinder block and the upper oil pan are fixedly coupled together via an interposed liquid gasket. Thus, the seal structure in which the liquid gasket is adequately cured is provided, and sufficient sealing properties can be obtained with a small amount of material used.

Abstract: The fuel pump driving structure includes a camshaft and a pump cam member. The camshaft is rotatably supported at an end by a cylinder head. The pump cam member has a fitting hole into which the end of the camshaft is press fitted, and is operatively coupled to a high-pressure fuel pump. The pump cam member includes a pump cam section and a first contact section. The pump cam section has a first lift portion operating the high-pressure fuel pump, and a base circular portion that does not operate the high-pressure fuel pump. The first contact section is in a position offset from a position of the first lift portion with respect to a circumferential direction and contacting a portion of the camshaft in an axial direction at a position radially outward of an external circumferential surface of the one end of the camshaft.

Abstract: A transmission shift fork engages with a coupling sleeve of a synchronizer and shifting the coupling sleeve. The transmission shift fork includes a first part, second part, and at least one fin. The first part is arranged to movably mount the transmission shift fork in a shift fork movement direction. The second part includes a coupling sleeve facing surface, an outwardly facing surface, and a pair of shift-direction facing surfaces. The coupling sleeve facing surface includes at least one coupling sleeve engagement part arranged to engage with an engaging groove formed on an external circumferential surface of the coupling sleeve. The outwardly facing surface includes an oil catch disposed in a position with respect to the coupling sleeve engagement part such that the oil catch captures lubricating oil and supplies to the coupling sleeve engagement part. The fin projects from inside an oil receiving recess defined by the oil catch.

Abstract: The fuel pump driving structure includes a camshaft and a pump cam member. The camshaft is rotatably supported at an end by a cylinder head. The pump cam member has a fitting hole into which the end of the camshaft is press fitted, and is operatively coupled to a high-pressure fuel pump. The pump cam member includes a pump cam section and a first contact section. The pump cam section has a first lift portion operating the high-pressure fuel pump, and a base circular portion that does not operate the high-pressure fuel pump. The first contact section is in a position offset from a position of the first lift portion with respect to a circumferential direction and contacting a portion of the camshaft in an axial direction at a position radially outward of an external circumferential surface of the one end of the camshaft.

Abstract: A transmission device includes an output shaft, first and second input shafts, a first gear mechanism, a selective fixing device and a connecting and disconnecting device. The second input shaft is coaxially arranged on an outside periphery of the first input shaft. The first gear mechanism couples the first input shaft and the output shaft with a first gear ratio. The first gear mechanism includes an idle gear mounted on one of the first input shaft and the output shaft. The selective fixing device selectively fixes the idle gear to one of the first input shaft and the output shaft. The second gear mechanism couples the second input shaft and the output shaft with a second gear ratio. The connecting and disconnecting device selectively connects and disconnects the second input shaft to the rotating shaft.

Abstract: A clutch device is configured to switch between a first clutch and a second clutch. The clutch device includes a fixed sleeve having a first male thread. The fixed sleeve is coaxially arranged around an exterior of a second input shaft. A first slider has a first internal female thread and a second external male thread. The first slider is arranged externally around the fixed sleeve. The second slider has a second internal female thread. The second slider is arranged around the exterior of the first slider to rotate and move in an axial direction. A first release bearing member is interposed between a member on the first clutch side and the second slider. A second release bearing member is interposed between a member on the side of the second clutch and the first slider. A first motor rotates the first slider. A second motor rotates the second slider.

Abstract: A vapor-liquid separating structure for an engine includes an inlet section, a discharging section, a collecting section and a vapor-liquid separating section. The inlet section is configured and arranged to take in blow-by gas from inside a valve mechanism chamber. The discharging section is configured and arranged to discharge the blow-by gas taken in through the inlet section. The collecting section is configured and arranged to collect a majority of oil entered into the vapor-liquid separating structure through the inlet section. The vapor-liquid separating section is configured and arranged to execute a vapor-liquid separation treatment with respect to the blow-by gas while guiding the blow-by gas taken in through the inlet section to the discharging section without the blow-by gas passing through the collecting section.

Abstract: A three cylinder engine includes a vibration alleviation unit for alleviating vibrations in a vehicle. The vibration alleviation unit is disposed at least one of upon the crankshaft and upon a part that operates in unison with the crankshaft. The three cylinder is supported by engine mounts that are positioned upon at least both ends of the engine in the direction of the crankshaft axis. Given that KV and KH represent spring constants of one of the engine mounts in the pitch and yaw directions of the crankshaft, MV and MH represent components of a primary couple that occurs in the three cylinder engine in the pitch and yaw directions, and MV0 represents the sum of MV and MH, then spring constants of the engine mounts are set such that KV>KH and the vibration alleviation unit is set so as to satisfy the condition 0<MV/MV0<0.5.

Abstract: A fuel injector assembly includes a modular fuel injector unit and a cylinder head side member. The modular fuel injector unit includes a first fuel injector with a first seal, a second fuel injector with a second seal and a fuel distribution pipe coupled together as a single installable unit. The cylinder head side member includes a first insertion hole with a first fitting section and a second insertion hole with a second fitting section. The first and second insertion holes and the first and second seals of the first and second fuel injectors are arranged such that as the modular fuel injector unit is being mounted to the cylinder head side member, the first seal undergoes a maximum compressive deformation in the first fitting section at a time that does not coincide with a time that the second seal undergoes a maximum compressive deformation in the second fitting section.

Abstract: A cooling system for cooling an internal combustion engine includes a first portion, a second portion and a bypass valve. The first portion forms a first fluid chamber through which a cooling medium passes as it flows from the engine to a heater that utilizes heat generated by the internal combustion engine. The second portion forms a second fluid chamber through which the cooling medium passes as it flows from the heater to the engine. The second fluid chamber is arranged adjacent to the first fluid chamber. The bypass valve is arranged inside the first fluid chamber and the second fluid chamber to form a bypass flow passage connecting the first fluid chamber and the second fluid chamber. The bypass valve is configured and arranged to automatically close the bypass flow passage when a temperature of the cooling medium is equal to or higher than a first prescribed temperature.

Abstract: A transmission shift fork engages with a coupling sleeve of a synchronizer and shifting the coupling sleeve. The transmission shift fork includes a first part, second part, and at least one fin. The first part is arranged to movably mount the transmission shift fork in a shift fork movement direction. The second part includes a coupling sleeve facing surface, an outwardly facing surface, and a pair of shift-direction facing surfaces. The coupling sleeve facing surface includes at least one coupling sleeve engagement part arranged to engage with an engaging groove formed on an external circumferential surface of the coupling sleeve. The outwardly facing surface includes an oil catch disposed in a position with respect to the coupling sleeve engagement part such that the oil catch captures lubricating oil and supplies to the coupling sleeve engagement part. The fin projects from inside an oil receiving recess defined by the oil catch.