Engine water pump structure

An engine comprising:

• a crank case;
• a crank shaft rotatably mounted in said crank case;
• a driven member interacting with said crank shaft to rotate in response to rotation of said crankshaft;
• a first engaging member connected to said driven member to rotate therewith;
• a water pump body attached to said engine;
• a water pump shaft having a first end and a second end, said water pump shaft being directly and rotatably attached to said water pump body;
• a water pump impeller included proximate said first end;
• and
• a second engaging member included proximate said second end, said second engaging member being engaged by said first engaging member to cause said water pump shaft and said water pump impeller to rotate in response to rotation of said first engaging member, wherein said second engaging member is a notch formed in said second end of said water pump shaft, and wherein said first engaging member is a protruding member adapted to mate within said notch.

A method of forming a water pump shaft of a water pump comprising the steps of:

• providing a die with a cylindrical opening of a first diameter formed therein;
• a punch having a circular groove formed in an end thereof with a protruding cylindrical portion inside the circular groove, the cylindrical protruding portion having a second diameter;
• and a hollow shaft with a third outer diameter approximately equal to the first diameter and a fourth inner diameter approximately equal to the second diameter;
• inserting one end of the hollow shaft into the circular opening of the die;
• inserting the cylindrical protruding portion into the hollow shaft until the hollow shaft seats into the circular groove;
• moving the punch toward the die;
• inserting the cylindrical protruding portion into the circular opening;
• and
• bending the hollow shaft in a radial direction at a point where the hollow shaft enters the die.

A water pump for an engine comprising:

• a water pump body having an approximately cylindrical support section of a first diameter and a first length, wherein said first length is longer than said first diameter;
• a water pump shaft having a first end, a second end, and a second diameter, said second diameter being approximately equal to said first diameter, said water pump shaft lying within said cylindrical support section to be directly and rotatably attached to said water pump body;
• a water pump impeller included proximate said first end;
• and
• a notch formed in said second end of said water pump shaft for engaging with a protruding member adapted to mate within said notch for causing said water pump shaft and said water pump impeller to rotate relative to said water pump body.