Kawasaki Jukogyo Kabushiki Kaisha

Ryo Iwata

Yasuhisa Okabe

Atsushi Ueshima

Nobumasa Taniguchi

Takeshi Moritomo

A crankcase for a multiple-cylinder four-cycle engine, including an upper crankcase and a lower crankcase which are joined to each other at a joint surface; a separating wall which is integrally cast with the upper crankcase and the lower crankcase to extend from the joint surface toward the opposite side of the joint surface and are configured to define crank chambers corresponding to adjacent cylinders; and a crank journal bearing hole which is formed on the separating wall and is configured to support a crankshaft. At least the separating wall formed in the upper crankcase has a thickness that increases from the joint surface of the crankcase to a region near a deepest portion of the crank journal bearing hole and decreases from the region near the deepest portion of the crank journal bearing hole toward the opposite side of the joint surface of the crankcase.

Crankcase, method of casting a crankcase, and a multiple-cylinder four-cycle engine comprising the crankcase

There is provided a vehicle frame structure for a motorcycle having an appealing appearance, which structure can be assembled lightweight and compact in size and at a reduced cost. The vehicle frame structure includes a head block () including a head tube (), a main frame () forked leftwards and rightwards from the head block () to form a pair of main frame half portions () extending rearwardly thereof, and swing arm brackets () extending downwardly from rear ends of the main frame half portions (). An inner frame portion () of the main frame () and the swing arm brackets () in their entirety or respective inner portions of the swing arm brackets () are integrally formed by an inner member () prepared from a metal casting, and at least an outer frame portion of the main frame () is formed by an outer member () prepared from a sheet metal.

Growing community of inventors

Akashi, Japan

Ryo Iwata