| 摘要 |
PURPOSE:To improve rigidity of a diaphragm, to enlarge a piston area and to reduce a cost by retaining an approximately truncated conical shape paper and by making it into a light-weighed flat diaphragm of a canape construction with a flat surface member anchored on its forward. CONSTITUTION:Plural grooves 23a V-shaped in the diameter direction are provided along a bus 19 of an approximately truncated conical shape paper, and V-shaped grooves 21a such as a coaxial circle 20a orthogonal with respect to the groove 23a, etc., are provided. A flat part 25a, etc., are formed between both V-shaped grooves, and by anchoring a circular thin plate 27 on the front surface of a transmission member 18 consisting of the flat part 25a and an approximately truncated conical shape side wall 26, a flat diaphragm is formed. The flat diaphragm has a two-layer construction with ribs, so called a canape construction, and its rigidity is improved. Thus a piston area can be enlarged and a cost can be substantially reduced. |
