Disk apparatus having optical pickup

[0018] The present invention is made in view of the problem and circumstances mentioned above, and an object thereof is to provide a disk apparatus having an optical pickup where the demand for guiding the bearing by the guide shaft with high accuracy without any backlash is satisfied, the bearing can be molded of a synthetic resin integrally with the base without the use of a metal mold slide pin or even if a metal mold slide pin is used, by use of a short metal mold slide pin and a general-purpose split-cavity mold, and the area of contact between the bearing and the guide shaft can be reduced to reduce the load on the motor.

[0019] A disk apparatus having an optical pickup according to the present invention is such that in a disk apparatus having an optical pickup where a base formed of a synthetic resin molding on which an optical system that scans a disk being rotated is mounted has a bearing slidably supported by a guide shaft that is circular in cross section and an engagement portion guided by a guide rail disposed parallel to the guide shaft, and the guide shaft is inserted in a round hole having a cylindrical sliding surface for which a hole is provided in the bearing; instead of providing the round hole in the bearing, a concave portion having a shape that enables forming die extraction in a direction orthogonal to a direction of an axis line and a pressing piece pressing the guide shaft inserted in the concave portion to thereby prevent the guide shaft from coming out of an open part of the concave portion are provided on the bearing so as to be displaced in the direction of the axis line, and an inner surface of the concave portion and a surface of the pressing piece constitute a sliding surface for the guide shaft.

[0020] According to this structure, the concave portion of the bearing can be molded by use of, for example, a split-cavity mold without the use of a metal mold slide pin, and the guide shaft inserted in the concave portion is pressed by the pressing piece to be prevented from coming out of the concave portion. Moreover, since the inner surface of the concave portion and the surface of the pressing piece constitute the sliding surface for the guide shaft, the demand for guiding the bearing by the guide shaft with high accuracy without any backlash is satisfied, and the bearing can be molded of a synthetic resin integrally with the base without the use of a metal mold slide pin. In addition, since the guide shaft is in contact only with the sliding surface constituted by the inner surface of the concave portion and the surface of the pressing piece and the entire peripheral surface of the guide shaft is not in contact with the sliding surface, the area of contact is reduced accordingly to reduce the load on the motor.

[0021] According to the present invention, the following structure may be adopted: The concave portion has a bottom surface slidably sandwiching the guide shaft in a first radius direction in cooperation with the surface of the pressing piece and a pair of opposing surfaces provided so as to rise from both ends of the bottom surface and slidably sandwich the guide shaft in a second radius direction orthogonal to the first radius direction. According to this structure, since the guide shaft is in contact only with the four surfaces of the surface of the pressing piece and the bottom surface and the pair of opposing surfaces of the concave portion, the area of contact can be significantly reduced to reduce the load on the motor.

[0022] According to the present invention, the following structure may be adopted: The bearing includes a pair of front and rear bearing elements slidably supported by the guide shaft, and at least one of the bearing elements has the concave portion and the pressing piece. According to this structure, since the concave portion of one of the bearing elements can be molded by use of, for example, a split-cavity mold without the use of a metal mold slide pin, even if the sliding surface of the other bearing element is molded by use of a metal mold slide pin, a short metal mold slide pin can be used, so that the overall size of the molding machine for molding the base can be reduced accordingly and the number of necessary metal mold parts can be small. This reduces the cost of the metal mold and the cost for molding the base. Moreover, the metal mold slide pin hardly deforms or breaks, so that the cost required for replacing the metal mold slide pin is low.

Moreover, the elongate metal mold slide pin 70 readily deforms or breaks because of being long and further, the cost required for replacing the metal mold slide pin 70 is high.

The disk drive apparatus described in JP-A-2001-222823 has a similar problem as the conventional example because the optical pickup thereof has the structure where the bearing having round holes is slidably supported by the-main guide shaft and the engagement portion having upper and lower protruding pieces is slidably engaged with the sub guide shaft.

Moreover, the art described in JP-A-2003-77234 cannot be a solution to the above-mentioned problem because it merely provides a structure of the second bearing portion not required of very high accuracy.

Further, the mechanism described in JP-A-61-175712 cannot be a solution to the above-mentioned problem, either, because it has the structure where the cylindrical bearing in which the guide rod is slidably inserted is held by the U-shaped holders.