To reduce centrifugal stress in a high speed rotation so as to provide sufficient high speed rotation when speed increase is carried out by a single level by forming an impeller casing of a material which is low in specific gravity and high in allowable stress.
In a fluid coupling, a rotational speed of a driving shaft 3 is increased by means of a speed increasing gear unit constructed of a large gear 2 and a small gear 4. An output shaft 5 is arranged adjacently to the driving shaft 3 and coaxially with the driving shaft 3. An impeller 6 is connected to the driving shaft 3, while a runner 7 is connected to the output shaft 5. In the impeller 6, an impeller casing 8 is fixed. The impeller casing 8 is made of a material, which is low in specific gravity and high in allowable stress, such as titanium alloy. In this way, centrifugal stress in a high speed rotation time can be lowered. Therefore, breakage due to stress can be prevented even if the fluid coupling unit is rotated at a high speed. As a result, no installation of a speed increase gear unit on the output side is required, and a casing dimension can be reduced.
SUGIYAMA KAZUHIKO
HATTORI KAZUO
OTSUKA MICHIO
OGATA TAIYO
