Honda Motor Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha

Hiroyuki Kawakubo

Toru Gunji

Hiromi Sumi

Yuichi Tawarada

Tetsuya Nakayasu

Atsushi Ogasawara

Hiroshi Nakagome

Satoru Narita

Toshio Shimada

Toshihisa Nagashii

Kazuyuki Nakai

Eiko Shiozaki

Shinichi Nakano

Tadashi Kato

Atsushi Sawa

Hisao Otsuka

Tadashi Katoh

Nobuyuki Oya

Tatsuya Hirata

Hiroshi Wakoh

A transmission structure of a power unit for a vehicle includes a clutch mechanism that is provided between a crankshaft and a main shaft, and is installed at the end of the main shaft outside a crankcase. The transmission includes a shift drum for driving shift forks for selectively establishing any of plural speeds. Both ends in an axial direction of the shift drum are rotatably supported by the crankcase. In the transmission structure, a sealed structure dedicated to the shift drum is not required, the number of parts is reduced and the assembly time is reduced. The shift drum, arranged in the maximum outside diameter of the clutch mechanism when viewed in a plane perpendicular to the axis of the main shaft, is assembled in the crankcase from the side of the clutch mechanism.

Vehicular power unit with improved transmission structure

A vehicular power unit including a drive-side transmission sprocket wheel provided on an end of an output shaft that protrudes from one side of a crankcase, an endless transmission belt for transmitting power to a driving wheel wound the sprocket wheel. The endless transmission belt transmits power from the crankshaft to a transmission housed in the crankcase. A water pump is arranged on the same side of the crankcase in a position between the crankshaft and the output shaft. Further, the water pump is disposed inside the drive-side transmission sprocket wheel in a direction along the axis of an output shaft. This configuration enables the vehicular power unit to be formed in a compact size in a direction along an axis of a crankshaft.

Vehicular power unit

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 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.

Threaded fastener for an internal combustion engine, and internal combustion engine incorporating same

A cylinder block of a multicylinder engine, having a cylinder main body in which multiple cylinder bores are provided in parallel in an axial direction of a crankshaft, and a crankcase having plural journal walls. The crankcase is integrally provided with the cylinder main body, in which a communication hole extending in parallel to the axial line of the crankshaft is provided in the cylinder main body and the crankcase while at least a part of which is opened in the inner peripheral surface of the cylinder bore. This permits the cylinder block to be downsized, increases freedom of positional setting of the communication hole, and reduces ventilation resistance of air flow through the communication hole. A cut-processed member is expanded further outward from a piston slide surface and is formed along a radial direction of cylinder bores, in inner surfaces of the cylinder bores in at least portions closer to a piston at an open edge of a communication hole.

Cylinder block for multicylinder engine

A piston cooling structure for a multicylinder engine having oil jets for ejecting oil toward pistons. The oil jets are mounted in each of a plurality of journal walls except one journal wall. The piston cooling structure is able to supply oil to a cylinder head in a position closer to a central region along the axis of the crankshaft while avoiding a complex oil passage shape. An oil passage for guiding oil to a cylinder head is defined in the one of the journal walls without an oil jet, and this one journal wall is disposed between a pair of adjacent cylinder bores. Oil jets are mounted in each of the other journal walls. A crankshaft of the engine is rotatably supported by the journal walls.

Piston cooling device for multicylinder engine

To suitably keep the weight balance of an engine while reducing a radial dimension of the engine. A crank shaft and a transmission shaft are supported in casings and are disposed to be substantially parallel to each other. A rear balancer and a front balancer are disposed with the crank shaft placed therebetween. An AC generator is disposed at an end portion of the crank shaft on the left side with respect to a plane passing through a center of gravity of an engine and being perpendicular to the crank shaft. A clutch is disposed at an end portion of the transmission shaft on the right side with respect to the plane. The clutch is separated from the plane at a distance smaller than that between the AC generator and the plane, so that the weight balance of the engine is suitably maintained by disposing the rear balancer and the front balancer on the clutch side.

Growing community of inventors

Saitama, Japan

Hiroyuki Kawakubo