Air compressor of weight-reduction type

An improved air compressor of the type including

• a main housing,
• a cylinder being fitted with a piston body having a piston head,
• an air storage unit communicating with the cylinder,
• a motor fitted with a small gear at an axle thereof, and
• a large gear mounted to the main housing via a bearing,
• wherein the main housing is joined with the cylinder, the motor and the large gear are mounted to the main housing such that the small gear engages with the large gear, the large gear is provided with a counterweight being fixed with a crankpin, the piston body is pivotally mounted to the crankpin, the motor drives the crankpin to swing in a circle, which allows the piston body to conduct reciprocating motion within the cylinder to compress air in the inner space of the cylinder and force the compressed air to flow into the air storage unit;
• wherein the improvement comprises:
• the bearing is formed integrally with the main housing, so that when the piston body conducts reciprocating motion within the cylinder at high frequencies, the bearing is firmly fixed on the main housing,
• the counterweight is mounted in a central opening of the large gear and flush with the large gear to reduce the distance between the main housing and the cylinder,
• the main housing is provided with a first portion for mounting the motor and a second portion for holding the bearing, and a crankshaft is fixed at one end to the counterweight and mounted at the other end to the bearing, so that the large gear is capable of driving the crankpin to swing in a circle around crankshaft so as to drive the piston body to conduct reciprocating motion within the cylinder,
• a cooling fan is provided at a rear end of the axle of the motor for dissipating the heat generated from the reciprocating motion of the piston body, the main housing defines at least one through hole for guiding the air flow, generated by the cooling fan, to flow through the main housing, and the main housing is formed with two lateral walls and a bottom wall to form a wind collecting hood, wherein the second portion is located within the wind collecting hood and held by multiple radial braces formed between the second portion and the wind collecting hood so as to facilitate the air flow, generated by the cooling fan, being introduced through the main housing for rapidly dissipating the heat generated from the reciprocating motion of the piston body within the cylinder, thereby increasing the operational security.