Impact driving tool

A driving tool comprising:

• a main body housing forming an external appearance of the driving tool;
• a cylinder provided so as to freely rotate relative to the main body housing by a ball bearing and freely move forward and backward through a slide bearing;
• a rotation and driving transmitting unit which drives to rotate the cylinder in accordance with a rotating movement of a motor;
• a forward and backward driving converting unit which converts the rotating movement of the motor into a forward and backward movement in an extending direction of the cylinder by using a reciprocating mechanism;
• a piston cylinder which is driven to move forward and backward in the extending direction by the forward and backward driving converting unit;
• a striking member which moves forward and backward in the cylinder in accordance with the forward and backward movement of the piston cylinder;
• and
• an intermediate member which transmits an impact force by the striking member to a bit provided at an end of the cylinder from an inner part of the cylinder, wherein a diameter of the intermediate member is enlarged to increase a mass of the intermediate member,
• an outside diameter of the cylinder at a position where the intermediate member is internally provided is enlarged in accordance with an enlargement of the diameter of the intermediate member,
• a bearing thickness of the ball bearing is reduced correspondingly to a dimension of the enlarged outside diameter of the cylinder,
• and a washer is provided at a part where the ball bearing abuts on the cylinder in the forward and backward moving direction of the cylinder.