Vibrator
A vibrator has a cup-shaped casing, a substrate provided to close an upper end opening of the casing, a magnetic circuit assembly provided in the casing, a first suspension and a second suspension that support the magnetic circuit assembly from above and below, and a voice coil secured to the substrate and inserted into a magnetic gap in the magnetic circuit assembly. The first suspension has an inner fixed portion that is secured to the substrate and that has a radially inner ring-shaped portion and a pair of extensions extending radially outward from mutually diametrically opposing positions on the ring-shaped portion. The first suspension further has a pair of leaf spring portions arcuately extending from the respective extensions through an angle of about 270 ° in symmetry to each other around the axis of the voice coil. Further, the first suspension has outer fixed portions disposed at the distal end portions of the leaf spring portions and secured to the upper end surface of a weight of the magnetic circuit assembly.
1. A vibrator comprising:
a casing having a bottom wall and a tubular side wall extending from said bottom wall;
a substrate provided to close an opening of said tubular side wall opposite said bottom wall;
a magnetic circuit assembly provided in said casing, said magnetic circuit assembly having a yoke with a bottom wall portion facing the bottom wall of said casing and a tubular peripheral wall portion extending from said bottom wall portion, said magnetic circuit assembly further having a magnet and a top plate that are successively stacked on the bottom wall portion of said yoke, wherein a magnetic gap is formed between an inner peripheral surface of the peripheral wall portion of said yoke and an outer peripheral surface of said top plate;
a voice coil secured to said substrate and inserted into said magnetic gap in concentric relation to the peripheral wall portion of said yoke;
a first suspension connected between said substrate and said magnetic circuit assembly; and
a second suspension connected between said magnetic circuit assembly and the bottom wall of said casing;
wherein said first suspension has at least one spring portion arcuately extending around said voice coil, said spring portion having an inner end and an outer end in a radial direction with respect to an axis of the peripheral wall portion of said yoke, said inner end being secured to said substrate, and said outer end being secured to said magnetic circuit assembly.
2. A vibrator according to claim 1 , wherein said first suspension has an inner fixed portion that is secured to said substrate, and has two said spring portions, said two spring portions being connected at said inner ends to mutually diametrically opposing positions on said inner fixed portion and extending in symmetry to each other around said axis.
3. A vibrator according to claim 2 , wherein said two spring portions each extend through an angle of at least 180° around said axis from said inner end to said outer end.
4. A vibrator according to claim 3 , wherein said two spring portions each extend through an angle of about 270° with respect to said axis from said inner end to said outer end.
5. A vibrator according to claim 1 , wherein said magnetic circuit assembly has a tubular weight secured to an outer peripheral surface of the peripheral wall portion of said yoke, and the outer end of said spring portion is secured to an end surface of said weight.
6. A vibrator according to claim 2 , further comprising:
a mounting member insert-molded together with the inner fixed portion of said first suspension and secured to said substrate coaxially with said axis;
wherein said voice coil is connected to said substrate through said mounting member.