Belt transmission apparatus

A belt transmission apparatus, comprising:

• a rotating electric machine pulley of a rotating electric machine for transmitting starting power to an engine;
• an engine pulley for transmitting the starting power to said engine and also transmitting a rotation power of said engine to an accessory;
• an auxiliary pulley being driven to rotate by the power from said engine pulley thereby to drive said accessory;
• a belt wrapped around said rotating electric machine pulley, said engine pulley and said auxiliary pulley in succession;
• and
• a belt tension adjuster for urging said belt so as to set a tension of said belt in a plurality of stages, wherein:
• said tension adjuster acts to adjust the tension of the belt such that the belt tension is set to be greater when said engine is started by said rotating electric machine than when said accessory is driven to operate after said engine has been started;
• said engine comprises a vehicular engine;
• and
• the position of said tension adjuster is set by a signal from a central processing unit which processes information comprising, at least, an rpm of said engine, an engine starting signal, a vehicle speed, and the tension of said belt.

A belt transmission apparatus, comprising:

• an electric machine pulley rotatably connected to a rotating electric machine;
• an engine pulley rotatably connected to a crankshaft of said engine;
• an auxiliary pulley rotatably mounted to an accessory;
• a tension pulley rotatably connected to a pulley unit,
• an automatic belt tensioner connected to said pulley unit;
• a belt wrapped around said electric machine pulley, said engine pulley, said auxiliary pulley and said tension pulley;
• wherein:
• said belt transmits starting power from said rotating electric machine to said engine, and transmits rotation power of said engine to said accessory;
• said pulley unit is movably connected to said engine;
• said automatic belt tensioner urges the movement of said pulley unit based upon an operational condition of the engine, thereby setting a tension in said belt that is greater when said engine is started by said rotating electric machine than when said engine is running and said belt is transmitting rotation power to said accessory, and
• said automatic belt tensioner comprises:
• a first cylindrical housing with first and second axial end walls;
• a piston, which is axially movable within said cylindrical housing, comprising a planar disk portion having an outer diameter equivalent to an inner diameter of the cylindrical housing;
• a push rod, which is axially movable within said cylindrical housing and extends through one of said axial end walls to contact said pulley unit, comprising a planar disk portion having an outer diameter equivalent to an inner diameter of the cylindrical housing;
• a first elastically deformable spring arranged between said disk portion of said piston and said disk portion of said push rod;
• and
• a control unit that axially moves said piston.

An automatic belt tensioner for use in an engine belt transmission apparatus, comprising:

• a first cylindrical housing with first and second axial end walls;
• a piston, which is axially movable within said cylindrical housing, comprising a planar disk portion having an outer diameter equivalent to an inner diameter of the cylindrical housing;
• a push rod, which is axially movable within said cylindrical housing and extends through one of said axial end walls to contact a tensioner to tension a belt on the vehicular engine, comprising a planar disk portion having an outer diameter equivalent to an inner diameter of the cylindrical housing;
• a first elastically deformable spring arranged between said disk portion of said piston and said disk portion of said push rod;
• and
• a control unit that axially moves said piston.