Variable pitch sheave assembly for fan drive system

A fan drive arrangement for operatively connecting a drive shaft to a fan mounted on a rotatable fan shaft, the fan generating an air flow through a radiator to cool the temperature thereof, comprising:

• first and second fan pulleys interconnected to the fan shaft, each fan pulley having a groove therein for receiving a corresponding fan belt;
• first and second drive pulleys interconnected to the drive shaft, each drive pulley having a groove therein for receiving a corresponding drive belt;
• a variable pitch sheave assembly movable between a first high speed position and a second low speed position, the variable pitch sheave including:
• a rotatable sheave shaft having first and second opposite ends;
• a first outer member fixed to the first end of the sheave shaft;
• a second outer member fixed to the second end of the sheave shaft;
• an intermediate member fixed to the sheave shaft between the first and the second ends thereof;
• a first slidable member slidable along the sheave shaft between the first outer member and the intermediate member;
• the first slidable member and the first outer member defining a first drive groove therebetween and the first slidable member and the intermediate member defining a first fan groove therebetween;
• a second slidable member slidable along the sheave shaft between the intermediate member and the second outer member;
• the second slidable member and the second outer member defining a second drive groove therebetween and the second slidable member and the intermediate member defining a second fan groove therebetween;
• a first drive belt seated in the groove in the first drive pulley and the first drive groove to translate rotation of the first drive pulley to the variable pitch sheave assembly;
• a second drive belt seated in the groove in the second drive pulley and the second drive groove to translate rotation of the second drive pulley to the variable pitch sheave assembly;
• a first fan belt seated in the first fan groove and the groove in the first fan pulley to translate rotation of the variable pitch sheave assembly to the first fan pulley;
• a second fan belt seated in the second fan groove and the groove in the second fan pulley to translate rotation of the variable pitch sheave assembly to the second fan pulley;
• an actuator operatively connected to the variable pitch sheave assembly for moving the variable pitch sheave assembly between the high speed position and the low speed position;
• and
• a controller operatively connected to the actuator and monitoring the temperature of the radiator, the controller controlling operation of the actuator in response to the temperature of the radiator.

A fan drive arrangement for operatively connecting a drive shaft to a fan mounted on a rotatable fan shaft, the fan generating an air flow through a radiator having coolant thereon to cool the temperature thereof;

• comprising:
• first and second fan pulleys interconnected to the fan shaft, each fan pulley having a groove therein for receiving a corresponding fan belt;
• first and second drive pulleys interconnected to the drive shaft, each drive pulley having a groove therein for receiving a corresponding drive belt;
• a variable pitch sheave assembly movable between a first high speed position and a second low speed position, the variable pitch sheave including:
• first and second drive belt grooves, the drive belt grooves having a first depth with the variable pitch sheave assembly in the high speed position and a second depth with the variable pitch sheave assembly in the low speed position;
• and
• first and second fan belt grooves, the fan belt grooves having a first depth with the variable pitch sheave assembly in the high speed position and a second depth with the variable pitch sheave assembly in the low speed position;
• first and second drive belts seated in corresponding drive belt grooves in the variable pitch sheave assembly and in corresponding grooves in the drive pulleys to translate rotation of the drive pulleys to the variable pitch sheave assembly;
• and
• first and second fan belts seated in corresponding fan belt grooves in the variable pitch sheave assembly and in corresponding grooves in the fan pulleys to translate rotation of the variable pitch sheave assembly to the fan pulleys;
• an actuator operatively connected to the variable pitch sheave assembly for moving the variable pitch sheave assembly between the high speed position and the low speed position;
• and
• a controller operatively connected to the actuator and monitoring the temperature of the coolant, the controller controlling operation of the actuator in response to the temperature of the coolant.