Honda Motor Co., Ltd.

Toru Gunji

Hiroyuki Kawakubo

Hiromi Sumi

Hiroyuki Sugiura

Takaaki Tsukui

Hayato Maehara

Shinji Saito

Hiroshi Nakagome

Toshihisa Nagashii

Hisao Otsuka

In a variable valve timing mechanism, a valve-lifting cam member is fitted, slidably in the circumferential direction, onto a camshaft that is driven to rotate in synchronization with a crankshaft of a four-stroke cycle internal combustion engine. An eccentric collar is set between a driving collar fixed on the camshaft and the valve-lifting cam member. A driving projection is formed in the driving collar and engages with one of sandwiching portions of the eccentric collar. A driven protrusion is formed in the valve-lifting cam member and engages with another one of the sandwiching portions of the eccentric collar. A linkage mechanism includes the eccentric collar, the drive, and the driven protrusions. The variable valve timing mechanism adjusts the timing of opening and closing of the valve while the rotational phase of the valve-lifting cam member is cyclically varied relative to the camshaft by the eccentricity of the eccentric collar.

Variable valve timing mechanism

In an engine for a motorcycle, a main shaft is supported rotatably by first and second support walls of a lower case which constitutes a part of a crank case. The center distance between the crank shaft and the main shaft is to be shortened while attaining a reduction in the number of parts and the number of assembling steps. A first bearing hole is formed in a first support wall for fitting therein and holding a first bearing which is mounted on one end of the main shaft. A second bearing hole is formed in a second support wall which permits the main shaft to be inserted therein from an opposite end side of the main shaft until one end of the main shaft is fitted in the first bearing. A second bearing is fitted and held in the second bearing hole so as to be fitted on the main shaft from the opposite end side of the main shaft after fitting of one end of the main shaft into the first bearing.

Engine for motorcycle

In an engine wherein an upper end portion of a casing of an oil strainer disposed within an oil pan is supported on a crank case side and a suction port is formed in a lower end of the casing whose lower portion is formed in a funnel shape, the oil strainer is supported firmly while preventing an increase in weight and size of the engine and an increase in the number of parts. A plurality of vertically long plate-like strainer support portions are integrally formed on a lower side face of a casing of an oil strainer for abutting against and for being supported by the bottom of an oil pan.

Oil strainer support structure in engine

A powertrain assembly having an improved engine configuration includes an engine and a transmission incorporated in a crankcase of the engine. The engine also comprises an oil pump and a water pump. The transmission is a cartridge-type shift drum transmission, which can be attached to or detached from a transmission attachment face which is a side face of the crankcase. The oil pump and the transmission attachment face are arranged in substantially non-overlapping relation in the side view of the engine. The water pump shaft is substantially coaxial with the oil pump shaft, and the water pump is positioned below a drive sprocket on the transmission countershaft so as to be overlapping while eliminating interference between them, allowing a close arrangement of components.

Powertrain assembly including modular transmission

The invention relates to a speed change gear drive for a transmission that can miniaturize an engine by improving the layout of parts. In particular, the invention relates to a speed change gear drive in which a change spindle is supported by a transmission case and a shift drum supported by the transmission case so that the shift drum can be rotated is driven by the turning of a change arm fixed to the change spindle, a shift fork the position of which is changed by the rotation of the shift drum and a shift fork rod that supports this shift fork are provided, and the change spindle and the shift fork rod are overlapped when the body of an engine is viewed from the side.

Speed change gear drive for transmission

By blocking off a partial passage opening in a lubricating oil supply passage of a transmission gear mechanism by attaching a transmission holder, an operation to block off the passage opening is omitted. Supply of lubricating oil to a main shaft and a counter shaft of a transmission gear mechanism is carried out using branched passages from a main gallery, and the branched passage constitutes a lubricating oil supply passage to the main shaft while the branched passage constitutes a lubricating oil supply passage to the counter shaft. A partial passage opening of the branched passage is then blocked up at the time of attaching a transmission holder to the transmission case, and in this way a lubricating oil supply passage to the counter shaft is formed.

Lubrication system for a transmission gear mechanism

To advance the pivotally supporting point of a swing arm on a vehicle body frame, the distance in the forward and backward direction between a crankshaft and a countershaft of a transmission is decreased as much as possible thereby making the length of the swing arm great and sufficiently absorb upward and downward oscillation of a rear wheel to achieve stabilization of the vehicle body. A countershaft is disposed below a main shaft of the transmission while a shift drum is disposed rearwardly of the main shaft, and a driving sprocket wheel for driving a rear wheel is provided on the countershaft. An internal combustion engine is disposed on the vehicle body frame such that a rear portion of a transmission is positioned above a pivotally supporting point of a swing arm. By the configuration, the pivotally supporting point of the swing arm can be advanced with respect to the internal combustion engine, and also the movable range of a rear portion of the swing arm is increased and the variation of the posture of the vehicle body can be reduced.

Motorcycle

To miniaturize an engine, to concentrate heavy masses and to reduce friction loss of a balancer. An engine crankcase structure in which a crankcase is vertically partitioned into an upper case and a lower case, each journal supporter is formed in the upper case and in the lower case so that the rotational axis of a crankshaft is located on a partition face of the crankcase in parallel with a direction of the width of the body. The crankshaft is supported so that the crankshaft can be rotated. An oil filter is directly attached to the lower case. An oil cooler and a secondary balancer are arranged in the front of the lower case.

Engine crankcase structure

The cartridge type transmission is a transmission configured to be detachable and attachable from/to the crankcase, the main shaft is arranged on the cut surface BF of the crankcase, and the change spindle and the shift fork shaft are pivotally supported in the upper crankcase, which is positioned on the upper side of the cut surface BF. The counter shaft is pivotally supported in the lower crankcase, which is positioned on the lower side of the cut surface BF.

Engine having a cartridge type transmission

A gear position detecting system includes structure which facilitates mounting of the system, and minimizes direct contact of other objects with the system. The outer circumferential surface of a shift drum, turned by operation of a change pedal, is provided with lead grooves. Shift forks, engaged with the lead grooves, are moved in the left-right direction by turning of the shift drum, whereby shift gears are changed over, and a speed change desired by the rider is performed. A detection pin of a neutral safety switch, which is one of gear position sensors, is pushed in by a detection cam of a cam surface provided at the outer circumferential surface of the shift drum in the speed change operation position, whereby a neutral position is detected.

Gear position detection system for a transmission

To facilitate attachment/detachment work of an oil filter in a vehicle engine without increasing an outer dimension thereof, and to provide a uniform a supply of engine oil into an engine body. An oil filter is attached onto a front portion of the engine body so as to be detachable in a vehicle body width direction from a side face of the engine body. An exhaust pipe on a side on which an oil filter is attached is displaced to a center side in the vehicle body width direction so as not to overlap the oil filter when viewed from a front of the engine body.

Vehicle engine

A multi-cylinder internal combustion engine draws oil from an oil reservoir with an oil pump, and supplies oil to individual areas of the engine, after passing the oil through an oil filter and an oil cooler. A filter case containing an element of the oil filter is mounted to a side surface of the engine to facilitate the removal and replacement of the case. The oil cooler and a balancer are each respectively mounted to a front central portion of the internal combustion engine to enable oil cooling by an air-cooling effect of a running airflow, and to balance weight in the left-right direction of the internal combustion engine. Oil discharged from the oil cooler is introduced to a substantially central portion of the main gallery, to achieve uniformity of oil pressure supplied to individual bearing portions and uniformity of cooling of the individual bearing portions.

Multi-cylinder internal combustion engine and vehicle incorporating same

A cylinder head, for an internal combustion engine, enhances engine efficiency while ensuring favorable coolant flow. The cylinder head includes a main casting bodyhaving a hollow water jacket formed therein, to allow coolant flow therethrough. The main casting bodyincludes a plurality of cylindrical plug hole wallswhich have plug holesformed therein inside a head-side water jacket. The cylinder head also includes partitions, formed inside the head-side water jacket, and these partitions connect the plug hole wallstogether form a dividing wall, which divides the water jacket into an exhaust port section and an intake port section. Coolant entering the water jacket is divided into two substreams, which flow initially in substantially opposite directions, and which are reunited after flowing around opposite ends of the dividing wall.

Cylinder head for an internal combustion engine

A threaded fastener is configured to reduce stress experienced at a female threaded portion of a hole formed in an engine block, when the threaded fastener is inserted therein, and when an axial load is applied thereto. In a particular application, a crankshaft is supported between a top supporting wall of a crankcase and a bottom supporting wall of a main cap. The inventive bolt includes a hollowed-out male threaded portion, which fits into a hole in the top supporting wall. The male threaded portion includes an elastically deformable low-rigidity portion, in which a cylindrical hole is concentrically formed. The maximum allowable stress of the top supporting wall is less than that of the bolt, due to material considerations. The low-rigidity portion is placed overlapping the female threaded portion in the axial direction, and since it is elastically deformable, it helps alleviate the stress experienced by the female threaded portion.

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Saitama, Japan

Toru Gunji