The loudspeaker includes a dome diaphragm that is made of a base material impregnated in a thermosetting resin; a cone diaphragm whose outer circumference side end portion is coupled with an outer circumference end portion of the dome diaphragm; and a voice coil having a bobbin whose one end is coupled to a back surface of the dome diaphragm, and whose outer curved surface is coupled with an inner circumference end portion of the cone diaphragm, wherein the dome diaphragm is provided with a plurality of cone-shaped projections that is formed by hardening the thermosetting resin, projecting from the back surface, and disposed in a circular pattern with a space between each other, the plurality of cone-shaped projections defining a coupling portion to which the one end of the bobbin is coupled.
1. A loudspeaker comprising:
a inversed dome-shaped diaphragm having a recess viewed from a front side, that is made of a base material impregnated in a thermosetting resin;
a cone diaphragm whose outer circumference side end portion is coupled with an outer circumference end portion of the dome diaphragm; and
a voice coil having a bobbin whose one end is coupled to a back surface of the dome diaphragm, and whose outer curved surface is coupled with an inner circumference end portion of the cone diaphragm, wherein
the dome diaphragm is provided with a plurality of cone-shaped projections that is formed by hardening the thermosetting resin, projecting from the back surface, and disposed in a circular pattern with a space between each other, the plurality of cone-shaped projections defining a coupling portion to which the one end of the bobbin is coupled,
a height of each of the plurality of cone-shaped projections provided for the dome diaphragm is set greater than a sum of maximum values of absolute values respectively of height tolerance of the dome diaphragm, height tolerance of the cone diaphragm, and height tolerance of the bobbin of the voice coil, and
a cone radius defining each cone-shaped projection is set greater than a maximum value of an absolute value of radius tolerance of the bobbin.
2. The loudspeaker according to claim 1 , further comprising:
an edge whose inner circumference end portion is coupled to the outer circumference end portion of the cone diaphragm;
a damper whose inner circumference end portion is coupled to the outer curved surface of the bobbin of the voice coil;
a frame to which the outer circumference end portion of the edge and the outer circumference end portion of the damper are coupled; and
a magnetic circuit to which the frame is coupled, the magnetic circuit having a magnetic gap in which a coil of the voice coil is provided.
3. The loudspeaker according to claim 2 , wherein
the dome diaphragm is further provided with an engagement flange along the outer circumference end portion, the engagement flange engaging with one of the outer circumference end portion of the cone diaphragm and an annular recess defined by a movable supporting portion of the edge.
4. The loudspeaker according to claim 1 , wherein
the cone diaphragm is further provided with a plurality of through holes in the vicinity of the inner circumference end portion of the cone diaphragm.
5. The loudspeaker according to claim 1 , wherein
the base material of the dome diaphragm contains one of woven fabric and nonwoven fabric made of fibers, and
the thermosetting resin contains an unsaturated polyester resin.