Receiver module having pressure equilibrium structure

1. A receiver module, comprising:

a casing including an upper casing having a sound insulation hole and a lower casing coupled to the upper casing and having a ventilation hole;

a receiver installed in an internal space defined by the casing and having a frame, a magnetic circuit, a voice coil, and a diaphragm; and

an air module disposed to surround a lower surface and an outer circumference of the receiver, fixed to an inner circumference of the casing, and provided to be mountable on the receiver such that an air path connecting the sound insulation hole and the ventilation hole is selectively provided between the outer circumference of the receiver and the inner circumference of the casing.

2. The receiver module of claim 1 , wherein the air module further defines a back volume for amplifying a sound through resonance at the outer circumference of the receiver.

3. The receiver module of claim 2 , wherein the air module includes a conduit formed in the back volume and having a communication hole communicating with outside apart from the back volume.

4. The receiver module of claim 1 , wherein the air module includes a circular metal part surrounding the receiver and an injection molded part from which the metal part is insert-injected and having the air path.

5. The receiver module of claim 1 , further comprising:

a microphone configured to cancel active noise,

wherein the microphone is located on a sound path including the air path so that ambient noise introduced through the ventilation hole through the air path is transferred to the microphone.

6. The receiver module of claim 1 , wherein the air path connects an upper space formed between the upper casing and the receiver and a lower space formed between the lower casing and the air module.

7. The receiver module of claim 1 , wherein the magnetic circuit is installed in the frame of the receiver, and wherein the magnetic circuit includes a cylindrical yoke coupled to the frame, a permanent magnet attached to the yoke, and a top plate attached to an upper portion of the permanent magnet.

8. The receiver module of claim 7 , wherein the air module is provided below the frame of the receiver and has a side wall formed to be spaced apart from a side wall of a yoke of the receiver, and wherein the air path is formed at a portion protruding outward from the side wall of the air module.