Chucking device, brushless motor, disk drive apparatus and method for manufacturing the chucking device

A chucking device for removably holding a disk with a central opening, comprising:

• a shaft coaxially arranged with a specified central axis;
• a turntable fixed to the shaft, the turntable including a disk support surface arranged to support the disk;
• a cone arranged axially above the turntable, the cone including a sliding portion arranged to make vertical sliding movement with respect to the shaft and a disk holding portion having an annular disk holding surface inclined radially outwards and axially downwards;
• an annular yoke arranged above the sliding portion of the cone and fixed to the shaft;
• and
• a clamp magnet fixed to the yoke through an adhesive agent;
• wherein the yoke includes an upper surface having an annular recess defined in a concentric relationship with the central axis, at least a part of the adhesive agent being applied on a region of the upper surface existing radially inwards of the recess;
• the recess includes a radial outer wall parallel to the central axis or inclined radially outwards and axially upwards, and a radial inner wall inclined radially inwards and axially upwards;
• and
• the angle between the radial outer wall and a lower surface of the clamp magnet is greater than the angle between the radial inner wall and the lower surface of the clamp magnet.

A method for manufacturing a chucking device arranged to removably hold a disk with a central opening, comprising the steps of:

• fitting a turntable to a shaft having a central axis from above to thereby fix the turntable to the shaft, the turntable including a disk support surface arranged to support the disk;
• fitting a cone to the shaft from above to thereby arrange the cone in such a way that the cone is axially slidable with respect to the shaft, the cone including an annular disk holding surface inclined radially outwards and downwards;
• fitting an annular yoke to the shaft from above to thereby fix the yoke to the shaft, the yoke including an upper surface having an annular recess defined thereon;
• applying an adhesive agent on a region of the upper surface of the yoke existing radially inwards of the annular recess;
• and
• fixing a clamp magnet to the upper surface of the yoke through the adhesive agent;
• wherein the recess includes a radial outer wall parallel to the central axis or inclined radially outwards and axially upwards and a radial inner wall inclined radially inwards and axially upwards;
• and
• the angle between the radial outer wall and the central axis is smaller than the angle between the radial inner wall and the central axis.

A method for manufacturing a chucking device arranged to removably hold a disk with a central opening, comprising the steps of:

• fitting a turntable to a shaft having a central axis from above to thereby fix the turntable to the shaft, the turntable including a disk support surface arranged to support the disk;
• fitting a cone to the shaft from above to thereby arrange the cone in such a way that the cone is axially slidable with respect to the shaft, the cone including an annular disk holding surface inclined radially outwards and axially downwards;
• fitting an annular yoke to the shaft from above to thereby fix the yoke to the shaft, the yoke including an upper surface having an annular recess defined thereon;
• applying an adhesive agent on a region of the upper surface of the yoke existing radially inwards of the annular recess;
• and
• fixing a clamp magnet to the upper surface of the yoke through the adhesive agent;
• wherein the recess includes a radial outer wall parallel to the central axis or inclined radially outwards and axially upwards and a radial inner wall inclined radially inwards and axially upwards;
• and
• the angle between the radial outer wall and a lower surface of the clamp magnet is greater than the angle between the radial inner wall and the lower surface of the clamp magnet.

A method for manufacturing a chucking device arranged to removably hold a disk with a central opening, comprising the steps of:

• applying an adhesive agent on a region of an upper surface of an annular yoke existing radially inwards of an annular recess defined on the upper surface of the yoke;
• fixing a clamp magnet to the upper surface of the yoke through the adhesive agent;
• fitting a turntable to a shaft having a central axis from above to thereby fix the turntable to the shaft, the turntable including a disk support surface arranged to support the disk;
• fitting a cone to the shaft from above to thereby arrange the cone in such a way that the cone can make vertical sliding movement with respect to the shaft, the cone including an annular disk holding surface inclined radially outwards and axially downwards;
• and
• fitting the yoke to the shaft from above to thereby fix the yoke to the shaft;
• wherein the recess includes a radial outer wall parallel to the central axis or inclined radially outwards and axially upwards and a radial inner wall inclined radially inwards and axially upwards;
• and
• the angle between the radial outer wall and the central axis is smaller than the angle between the radial inner wall and the central axis.

A method for manufacturing a chucking device arranged to removably hold a disk with a central opening, comprising the steps of:

• applying an adhesive agent on a region of an upper surface of an annular yoke existing radially inwards of an annular recess defined on the upper surface of the yoke;
• fixing a clamp magnet to the upper surface of the yoke through the adhesive agent;
• fitting a turntable to a shaft having a central axis from above to thereby fix the turntable to the shaft, the turntable including a disk support surface arranged to support the disk;
• fitting a cone to the shaft from above to thereby arrange the cone in such a way that the cone can make vertical sliding movement with respect to the shaft, the cone including an annular disk holding surface inclined radially outwards and axially downwards;
• and
• fitting the yoke to the shaft from above to thereby fix the yoke to the shaft;
• wherein the recess includes a radial outer wall parallel to the central axis or inclined radially outwards and axially upwards and a radial inner wall inclined radially inwards and axially upwards;
• and
• the angle between the radial outer wall and a lower surface of the clamp magnet is greater than the angle between the radial inner wall and the lower surface of the clamp magnet.