In-ear earphone

1. An in-ear earphone comprising:

a shell comprising a base and a cover connected to the base, the cover having a substantially half spherical inner surface, a first engaging portion being formed in the shell; and

a sound output device comprising a sound tunnel, a second engaging portion and a speaker, the sound tunnel comprising an opening end at one end and a containing portion at another end, the containing portion being received in the shell, the opening end being exposed to an outside of the shell, the speaker being accommodated in the containing portion and disposed coaxially with the sound tunnel, the second engaging portion being received in the shell and covering the containing portion of the sound tunnel, the speaker being disposed between the sound tunnel and the second engaging portion, the containing portion having a curved outer surface, the curved outer surface of the containing portion being movably engaged with the half spherical inner surface of the cover and the second engaging portion being movably engaged with the first engaging portion such that an angle between the shell and the sound output device is adjustable by the curved outer surface of the containing portion moving relative to the half spherical inner surface of the cover and the second engaging portion moving relative to the first engaging portion, whereby the sound tunnel is suitably plugged into individual user's ear canals.

2. The in-ear earphone of claim 1 , wherein the base also has a substantially half spherical inner surface and the half spherical inner surfaces of the base and the cover are combined to form a ball shaped cell in the shell, the ball shaped cell functioning as the first engaging portion.

3. The in-ear earphone of claim 1 , wherein a plurality of protrusions are formed on an outer wall of the containing portion and movably engaged with the half spherical inner surface of the cover.

4. The in-ear earphone of claim 1 , wherein the second engaging portion has a half spherical surface movably engaged with the base of the shell.

5. The in-ear earphone of claim 4 , wherein at least a stopping device is formed on the base, at least a positioning hole is formed on the second engaging portion, the at least a stopping device is inserted into the at least a positioning hole and the angular adjustment between the shell and the sound output device is limited between the at least a stopping device and the at least a positioning hole.

6. The in-ear earphone of claim 1 , wherein the sound tunnel has an opening end and a containing portion, the opening end being exposed to an outside of the shell, the containing portion begin configured for accommodating the speaker.

7. The in-ear earphone of claim 6 , wherein the second engaging portion has a tube shape, an end of the second engaging portion being engaged to the containing portion of the sound tunnel, another end of the second engaging portion having the cell for combining with the first engaging portion.

8. The in-ear earphone of claim 7 , wherein a plurality of protrusions are formed in the cell for blocking an angular adjustment between the sound output device and the shell.

9. The in-ear earphone of claim 1 , wherein the sound tunnel is made of polyoxymethylene (POM), and the second engaging portion is made of acrylonitrile butadiene styrene (ABS).

10. The in-ear earphone of claim 1 , wherein a grid cover is disposed inside the opening end of the sound tunnel of the sound output device for preventing dust from entering the sound tunnel.

11. The in-ear earphone of claim 1 , wherein the outside of the sound tunnel is wrapped around by a cushion, the cushion being made of an elastic material and suitable for being plugged into user's ear canals.

12. An in-ear earphone comprising:

a shell having a first engaging portion formed in the shell; and

a sound output device comprising a sound tunnel, a second engaging portion and a speaker, the sound tunnel comprising an opening end at one end and a containing portion at another end, the speaker being accommodated in the containing portion and disposed coaxially with the sound tunnel, the second engaging portion being connected with the containing portion and having a curved inner surface, the speaker being disposed between the sound tunnel and the second engaging portion, the first engaging portion being received in the second engaging portion and having a ball shaped outer surface, the curved inner surface of the second engaging portion being movably engaged with the ball shaped outer surface of the first engaging portion such that an angle between the shell and the sound output device is adjustable by the curved inner surface of the second engaging portion moving relative to the ball shaped outer surface of the first engaging portion whereby the sound tunnel is suitably plugged into individual user's ear canals, wherein the first engaging portion is monolithically formed to be extended from the shell, and a wire groove is disposed through the first engaging portion and the shell.