Disc clamping unit and spindle motor having the same

1. A disc clamping unit, the disc clamping unit comprising:

a case including a lateral wall unit formed with a hollow hole, and a support unit extended to an inner side of a distal end of the lateral wall unit;

a clamper arranged inside the lateral wall unit and supported by the support unit for clamping an upper surface of the optical disc;

a cover plate covering the clamper; and

an elastic member interposed between the clamper and the cover plate to apply a pressure to the clamper to a direction facing the upper surface of the optical disc,

wherein the elastic member includes a coil spring, and

wherein an area contacting the cover plate in the elastic member includes a plurality of first uneven units, and an area contacting the clamper in the elastic unit includes a plurality of second uneven units.

2. The disc clamping unit of claim 1 , wherein the clamper includes a boss protruded from a center of an upper surface of the clamper, and the cover plate is formed with a through hole inserted by the boss.

3. The disc clamping unit of claim 1 , wherein a first distal end contacting the cover plate in the elastic member is formed with a first diameter, and a second distal end contacting the clamper in opposition to the first distal end is formed with a second diameter greater than the first diameter.

4. The disc clamping unit of claim 1 , wherein a slip layer generating a rotational slip is formed between the cover plate and the elastic member and between the clamper and the elastic member.

5. The disc clamping unit of claim 1 , wherein the clamper includes a flat clamp unit contacting the elastic member and the optical disc, and a lug unit formed inside the elastic member and convexly protruded to an upper surface.

6. The disc clamping unit of claim 1 , wherein the clamper is a non-magnetic material.

7. The disc clamping unit of claim 6 , wherein the clamper is formed with synthetic resin.

8. The disc clamping unit of claim 1 , wherein the elastic member includes any one of a metal coil spring and a synthetic resin coil spring.

9. The disc clamping unit of claim 1 , wherein the elastic member includes a leaf spring pressing the clamper to a direction facing the optical disc.

10. A spindle motor, the spindle motor comprising:

a bearing assembly including a bearing and a bearing housing accommodating the bearing;

a stator including a core coupled to the bearing housing and a coil wound on the core;

a rotation shaft rotatably inserted into the bearing;

a rotor including a yoke coupled to the rotation shaft and a magnet arranged opposite to the core;

a turn table coupled to the rotation shaft to contact the yoke;

a center cone inserted into the rotation shaft and formed with a non-magnetic material to reciprocate along the rotation shaft; and

a disc clamping unit including a non-magnetic material clamper arranged on an upper surface of the turn table to contact the center cone and an elastic member applying an elasticity force to the non-magnetic material clamper to apply a pressure to the non-magnetic material clamper to a direction facing an upper surface of the turn table,

wherein an area contacting the cover plate in the elastic member includes a plurality of first uneven units, and an area contacting the clamper in the elastic unit includes a plurality of second uneven units.

11. The spindle motor of claim 10 , wherein the clamper is accommodated into a case, and the case includes a lateral wall unit formed with a hollow hole and a support unit formed inwardly along an edge of the lateral wall unit.

12. The spindle motor of claim 10 , further comprising slip layers, each formed between the cover plate and the elastic member and between the clamper and the elastic member.

13. The spindle motor of claim 10 , wherein the elastic member includes a coil spring.

14. The spindle motor of claim 10 , wherein the clamper is formed with a synthetic resin.

15. The spindle motor of claim 10 , wherein the elastic member includes any one of a metal coil spring and a synthetic resin coil spring.

16. The spindle motor of claim 10 , wherein the elastic member includes a leaf spring pressing the clamper to a direction facing the optical disc.

17. The spindle motor of claim 10 , wherein the clamper includes a boss protruded from a center of an upper surface of the clamper, and the cover plate is formed with a through hole inserted by the boss.