Earphone structure

An earphone structure, comprising:

• a speaker, comprising a casing, a sound producing vibrating diaphragm, and a sound outlet, wherein the sound producing vibrating diaphragm is provided inside the casing, the sound outlet is provided on a surface of the casing, wherein the sound producing vibrating diaphragm is used to convert an electrical signal to a sound which is output through the sound outlet;
• a pipe, wherein the pipe has one end provided at a side of the speaker having the sound outlet, and the other end extending along a direction away from the sound outlet, such that the sound output from the sound outlet is transmitted to an outside space;
• and
• a fixing portion provided in the casing, wherein the fixing portion is integrally molded with the pipe, such that the pipe is fixed to the speaker through the fixing portion,
• wherein areas of cross sections of the pipe in a radial direction are increasing successively in a direction away from the sound outlet,
• wherein each of the cross sections of the pipe in the radial direction comprises:
• a first arc-shape portion;
• a second arc-shape portion, having a radius of curvature smaller than that of the first arc-shape portion, wherein a first end of the second arc-shape portion is connected to a first end of the first arc-shape portion;
• a third arc-shape portion, having a radius of curvature equal to that of the first arc-shape portion, wherein a first end of the third arc-shape portion is connected to a second end of the second arc-shape portion;
• and
• a fourth arc-shape portion, having a radius of curvature equal to that of the second arc-shape portion, wherein a first end of the fourth arc-shape portion is connected to a second end of the third arc-shape portion, and a second end of the fourth arc-shape portion is connected to a second end of the first arc-shape portion.