Inhaler

1 . An inhaler comprising:

a housing having one surface, an other surface opposite to the one surface, and a plurality of side surfaces connecting the one surface and the other surface;

a mouthpiece which is disposed on the one surface of the housing;

a reservoir which is disposed inside the housing and stores an inhalable composition;

a nozzle which extends from the reservoir towards the mouthpiece;

a needle valve which is movably disposed inside the nozzle;

a piston which has one surface coupled to the needle valve, and vertically reciprocates in a first direction from the other surface to the one surface of the housing or a second direction from the one surface of the housing to the other surface of the housing; and

a spring which is provided below the piston in a preloaded state,

wherein, when a suction force is not applied to the mouthpiece, the needle valve is maintained in a first state in which the nozzle is closed,

wherein, when the suction force is applied through the mouthpiece, the needle valve is switched into a second state in which the nozzle is opened,

wherein, when the suction force is not applied to the mouthpiece, the spring pushes the piston up in the first direction to maintain the first state, and

wherein, when the suction force is applied through the mouthpiece, the piston overcomes preload of the spring and moves in the second direction to switch into the second state.

2 . The inhaler of claim 1 ,

wherein the first state is defined as a state in which the needle valve comes into contact with the nozzle, and

wherein the second state is defined as a state in which the needle valve does not come into contact with the nozzle.

3 . The inhaler of claim 1 , further comprising:

a passage which is formed inside the housing and extends from one side of the mouthpiece to a bottom portion of the piston,

wherein the passage transfers the suction force applied to the mouthpiece to the piston.

4 . The inhaler of claim 3 , further comprising:

a negative pressure forming portion which forms a space between the piston and the passage,

wherein the negative pressure forming portion induces the piston to move in the second direction by generating a negative pressure by the suction force.

5 . The inhaler of claim 1 ,

wherein the nozzle comprises:

a first nozzle portion adjacent to the mouthpiece; and

a second nozzle portion adjacent to the reservoir, and

wherein the first nozzle portion is formed to have a diameter smaller than a diameter of the second nozzle portion.

6 . The inhaler of claim 5 ,

wherein the needle valve comprises:

a first valve portion which is formed on a front end and vertically reciprocates in the first direction from the other surface to the one surface of the housing or the second direction from the one surface of the housing to the other surface of the housing through the first nozzle portion and the second nozzle portion; and

a second valve portion which is formed on a lower portion of the first valve portion,

wherein the first valve portion is formed to have a diameter smaller than a diameter of the second valve portion.

7 . The inhaler of claim 6 , wherein the first valve portion is formed to have the diameter smaller than the diameter of the first nozzle portion.

8 . The inhaler of claim 6 ,

wherein the first valve portion does not come into contact with the nozzle in the first state or the second state, and

wherein the second valve portion comes into contact with the nozzle in the first state and does not come into contact with the nozzle in the second state.

9 . The inhaler of claim 6 ,

wherein the nozzle further comprises a sealing member provided in the second nozzle portion, and

wherein the second valve portion comes into contact with the sealing member in the first state, and does not come into contact with the sealing member by moving in the second direction in the second state.

10 . The inhaler of claim 9 , wherein a first gap formed between the first valve portion and the first nozzle portion is smaller than a second gap formed between the first valve portion and the sealing member.

11 . The inhaler of claim 10 ,

wherein the first gap is formed in the first state or the second state, and

wherein the second gap is formed in the second state.

12 . The inhaler of claim 10 ,

wherein the second gap allows movement of the inhalable composition discharged from the reservoir, and

wherein the first gap allows the movement of the inhalable composition to the mouthpiece by controlling a particle size of the inhalable composition passing through the second gap.

13 . The inhaler of claim 10 , wherein the first gap is formed to be 0.015 mm to 0.03 mm.