Air supply system for a vehicle

1. An air supply system for vehicles comprising:

a motor part adapted to rotate a rotary shaft mounted at a center thereof, said motor part having an outer periphery;

a motor housing that is comprised of an inner cylinder and an outer cylinder and adapted to receive the motor part vertically inserted and mounted in the inner cylinder and having an air flow channel vertically formed between the inner cylinder and the outer cylinder on the outer periphery of the motor part;

an inlet duct coupled to an upper end of the motor housing for guiding air introduced through an inlet thereof to the air flow channel of the motor housing;

an impeller coupled to a lower end of the rotary shaft for compressing the air while rotating together with the rotary shaft;

an outlet duct having opened upper and lower ends and coupled to the lower end of the motor housing for compressing the air passing through the air flow channel of the motor housing by the impeller and discharging the compressed air to an outlet thereof and the upper end and the lower end of the outlet duct being opened; and

an end plate coupled to the lower end of the outlet duct in such a way as to seal the opened lower end of the outlet duct,

wherein the outlet duct comprises:

an impeller receiving portion formed on an inner lower end thereof for rotatably receiving the impeller therein and communicating with the air flow channel;

a diffuser passageway adapted for converting kinetic energy of the air blown through the impeller into pressure, and

volute for collecting air compressed while passing through the diffuser passageway and sending the collected air toward the outlet,

wherein an inner surface of a receiving wall portion forming the impeller receiving portion is curved along an outer surface of blades of the impeller,

wherein the diffuser passageway comprises:

a first passageway which is formed between a radially extended wall portion extending from an end of the receiving wall portion in a radial direction and the end plate; and

a second passageway formed between an upwardly bent wall portion extending from an end of the radially extended wall portion in an axial upward direction of the rotary shaft and an outer wall portion of the outlet duct,

wherein the volute is communicatingly formed on the upper portion of the second passageway and has a diameter gradually narrowed toward the outlet, and an inner wall portion of the volute is formed separately from the receiving wall portion with a space therebetween, and

wherein the outlet duct further comprises a guide for guiding the air through the air flow channel of the motor housing toward the air inlet of the impeller, the guide being formed separately from the impeller receiving portion and the volute and mounted between the motor housing and the impeller receiving portion, wherein one side of the guide is coupled to the end of the outer cylinder and the other side is coupled to the impeller receiving portion inside the outlet duct so that the guide covers the space between the inner wall portion of the volute and the receiving wall portion.

2. The air supply system according to claim 1 , wherein the second passageway of the diffuser passageway is formed at an angle of 90° in the upward direction from an end portion of the first passageway.

3. The air supply system according to claim 1 , wherein the inner peripheral surface of the guide is formed in a concave curvature ranging from the upper end thereof to an inflection point and in a convex curvature ranging from the inflection point to the lower end thereof.

4. The air supply system according to claim 1 , wherein the second passageway of the diffuser passageway extends toward the guide.

5. The air supply system according to claim 1 , wherein the second passageway of the diffuser passageway extends toward the air inlet of the impeller.

6. The air supply system according to claim 1 , wherein the second passageway of the diffuser passageway is formed inclinedly at an end portion of the first passageway.

7. The air supply system according to claim 1 , further comprising a bearing holder coupled to the upper end of the motor housing inside the inlet duct and having a bearing mounted on the inner peripheral surface thereof for rotatably supporting the upper end of the rotary shaft.

8. The air supply system according to claim 1 , wherein the end plate has a bearing mounted on the inner peripheral surface thereof for rotatably supporting the lower end of the rotary shaft.