Patent Application
20140223457
This application claims the benefit under 35 U.S.C. §119(a) of Korean Patent Application No. 10-2013-0013079, filed on Feb. 5, 2013, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes.
1. Field
The following description relates to a spindle unit for rotating an optical disc, a chucking structure for chucking the optical disc together with the spindle unit, and an optical disc drive including the chucking structure.
2. Description of Related Art
An optical disc drive typically includes a chucking structure for rotatably supporting and rotating a disc and an optical pickup unit for reading information from and/or writing information to the disc. The chucking structure may include a spindle unit on which the disc is mounted, and the spindle unit further includes a spindle motor for rotating the spindle unit and a clamper for fixing the disc onto the spindle unit.
The disc mounted on the spindle unit is chucked by the clamper. The chucking structure may be a magnetic chucking structure. In the magnetic chucking structure, a disc is disposed between the spindle unit and the clamper and chucked due to a magnetic attractive force acting between the spindle unit and the clamper. The clamper and the spindle unit may include a magnet and a yoke corresponding to the magnet, respectively. Alternatively, the clamper and the spindle may have a yoke and a magnet, respectively. However, because this conventional magnetic chucking structure causes noise when the spindle unit collides with the clamper for disc chucking, there have been long-felt needs for research to reduce chucking noise for quieter disc chucking operation. Furthermore, since a magnet is typically made of neodymium (Nd) which is an expensive rare-earth metal, the use of such an expensive metal may significantly increase manufacturing costs. Therefore, there is a need for a chucking structure configured to perform stable disc chucking and reduce the manufacturing costs.
In an aspect, there is provided a spindle unit comprising a spindle motor having a rotation shaft, a turntable that is coupled to the rotation shaft and supports a disc, and a sliding cone that is coupled to the turntable so as to elastically move up and down and is inserted into a hole formed at the disc. The sliding cone may include a bump protruding from a surface thereof, and the bump may have a concave portion recessed downward from a center thereof.
The concave portion may be aligned with the rotation shaft in a line.
The bump may have a diameter less than that of the surface of the sliding cone.
An extent to which the bump protrudes from the surface of the sliding cone may be 0.1 mm or more. The extent to which the bump protrudes from the surface of the sliding cone is 0.5 mm or more.
The turntable may further comprise at least one ball balancer which reduces vibrations.
The spindle unit may further comprise an elastic member interposed between the sliding cone and the turntable so as to elastically support the sliding cone.
In another aspect, there is provided a chucking structure comprising: a spindle unit comprising a spindle motor having a rotation shaft, a turntable that is coupled to the rotation shaft and supports a data storage device, and a sliding cone that is coupled to the turntable so as to elastically move up and down and is inserted into a hole formed at a disc, wherein the sliding cone includes a bump protruding from a surface thereof, and the bump has a concave portion recessed downward from a center thereof; and a clamper that is disposed to face the turntable and elastically support a surface of the data storage device. The clamper may comprise an insert protrusion configured to be inserted into the concave portion.
The concave portion may be aligned with the rotation shaft in a line.
The bump may have a diameter less than that of the top surface of the sliding cone.
The turntable may further comprise at least one ball balancer which reduces vibrations.
The spindle unit may further comprise an elastic member interposed between the sliding cone and the turntable so as to elastically support the sliding cone.
The spindle unit may further comprise a chucking spring for biasing the clamper toward the turntable.
In another respect, there is provided an optical disc drive comprising: a main frame; a tray which has an optical disc mounted thereon and is loaded/unloaded by sliding into/out of the main frame; a main base installed to move up and down with respect to the main frame in synchronization with loading/unloading of the tray; a spindle unit of mounted on the main base, the spindle unit comprising a spindle motor having a rotation shaft, a turntable that is coupled to the rotation shaft and supports the data storage device, and a sliding cone that is coupled to the turntable so as to elastically move up and down and is inserted into a hole formed at a disc, wherein the sliding cone includes a bump protruding from a surface thereof, and the bump has a concave portion recessed downward from a center thereof; an optical pickup unit mounted on the main base and corresponding to the optical disc, a cover covering an upper part of the main base, and a clamper that is disposed in the cover to face the turntable and elastically support a top surface of the optical disc and has an insert protrusion that is disposed at a center thereof and is inserted into the concave portion.
The spindle unit may further comprise an elastic member interposed between the sliding cone and the turntable so as to elastically support the sliding cone.
The tray may have first and second mounting surfaces on which discs having different sizes are mounted, respectively, and the second mounting surface may be recessed downward from the first mounting surface.
An extent to which the bump protrudes from the top surface of the sliding cone may be determined so that a distance between an edge of the bump and the bottom surface of the optical disc is 0.3 mm or more.
In another aspect, there is provided a disk apparatus comprising: a clamper comprising an insert protrusion on a surface of the clamper, and a rotational support on a surface of the clamper disposed to be concentric with the insert protrusion; and a chucking spring that is elastically movable up and down and is adapted to contact the rotational support.
The disk apparatus may further comprise a lubricating member disposed on a surface of the chucking spring and facing the clamper.
Centers of the insert protrusion, the rotational support, and the lubricating members may be arranged in a line.
Other features and aspects will be apparent from the following detailed description, the drawings, and the claims.
Throughout the drawings and the detailed description, unless otherwise described, the same drawing reference numerals will be understood to refer to the same elements, features, and structures. The relative size and depiction of these elements may be exaggerated for clarity, illustration, and convenience.
The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. Accordingly, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be suggested to those of ordinary skill in the art. Also, descriptions of well-known functions and constructions may be omitted for increased clarity and conciseness.
The features described herein may be embodied in different forms, and are not to be construed as being limited to the examples described herein. Rather, the examples described herein have been provided so that this disclosure will be thorough and complete, and will convey the full scope of the disclosure to one of ordinary skill in the art.
In this example, a main base 140 is provided to the main frame 110 and moves up and down with respect to the main frame 110. The main base 140 includes a spindle unit 170 for mounting and rotating an optical disc 1 and an optical pickup unit 150 for irradiating light on the optical disc 150 and for recording information on and/or reproducing the recorded information from the optical disc 1.
For example, the cover 130 includes a clamper 132 that is used in constructing a chucking unit for chucking the optical disc 1 together with the spindle unit 170.
The tray 120 is loaded on and unloaded from the main frame 110. The tray 120 is loaded by sliding into the main frame 110. The tray 120 is unloaded from the main frame 110 by sliding out of the main frame 110 so that the optical disc 1 having a center hole 1a can be retrieved from or mounted on the tray 120. The tray 120 includes an open window 124 for providing a space where the optical pickup unit 150 operates. The tray 120 may also include a first mounting surface 121 and a second mounting surface 122 for mounting two types of discs having different sizes. For example, the first and second mounting surfaces 121 and 122 may be provided for a disc having a diameter of 12 cm and a disc having a diameter of 8 cm, respectively. The first mounting surface 121 may be recessed in a top surface 123 of the tray 120, and the second mounting surface 122 may be recessed in the first mounting surface 121
[Structure Facilitating Moving Up and Down the Main Base 140]
A structure facilitating the moving up and down of the main base 140 will now be briefly described.
Referring to
When the tray 120 having the optical disc 1 mounted thereon starts to be loaded, the main slider 165 remains unmoved until the main base 140 starts moving from a lowered position. As the loading process continues, the tray driving gear 164 becomes separated from the first rack gear provided on the tray 120. At the same time, the first cam trajectory slightly moves the main slider 165 up from the lowered position so that the second rack gear disposed on the main slider 165 is connected with the main gear 163. The tray 120 stops at a loading end position, so that the spindle unit 170 of the main base 140 is aligned with the center hole 1a of the optical disc 1. In this example, when the driving motor continues to rotate, the tray 120 remains stationary and only the main slider 165 slides in the transverse direction. Then, the main base 140 rotates around the rotational axis 146 due to the second cam trajectory in the main slider 165 so that the spindle unit 170 ascends, thereby placing the optical disc 1 on the spindle unit 170. After the ascending operation of the spindle unit 170 is completed, the optical disc 1 is chucked by the spindle unit 170 and the clamper 132.
When the tray 120 is unloaded, a reverse operation of the above operation is performed. More specifically, as the main slider 165 slides in an opposite direction by the driving motor, the main base 140 rotatably moves downward, and the optical disc 1 is unchucked so that it rests on the tray 120. In this case, the tray 120 remains unmoved. When a descending operation of the main base 140 is almost completed, the tray 120 is slightly unloaded by the main slider 165 so as to connect the tray driving gear 164 to the first rack gear provided on the tray 120 and to disconnect the second rack gear on the main slider 165 from the main gear 163. The driving motor continues to rotate until the tray 120 slides out of the main frame 110 and therefore unloading of the tray 120 is completed.
[Chucking Structure]
An example of a structure for chucking the optical disc 1 will now be described in detail.
Referring to
Referring to
The sliding cone 174 may be coupled to the turntable 172 so as to elastically move up and down. The sliding cone 174 includes a hook type guide rod 174a extending down toward the turntable 172 and having a protrusion 174b at its front end. The turntable 172 includes a stopper 172c by which the protrusion 174b of the hook type guide rod 174a is hooked. An elastic member 175 elastically biases the sliding cone 174 upward, i.e., toward the clamper 132. For example, the elastic member 175 may be a compression coil spring interposed between the sliding cone 174 and the turntable 172. The sliding cone 174 includes a top surface 174c disposed opposite the clamper 132 and an oblique outer circumferential surface 174d flaring outward from the top surface 174c and extending obliquely downward. A bump 174e protrudes upward at the top surface 174c of the sliding cone 174, and has a concave portion 174f aligned with the rotation shaft 171a of the spindle motor 171 and recessed downward. For example, the bump 174e protrudes upward at a center of the top surface 174c and the concave portion 174f is concentric with the rotation shaft 171a. The insert protrusion 132c of the clamper 132 described above is fitted into the concave portion 174f during a chucking operation.
A chucking operation performed by the above-described chucking structure will now be described with reference to
Still referring to
In the optical disc drive including the chucking structure, a magnet and a yoke are not required to form the sliding cone 174 unlike in a conventional magnetic clamping structure. As a result, the structure of the spindle unit 170 may be simplified, and manufacturing costs may be reduced.
Furthermore, contrary to the conventional magnetic clamping structure, wherein the spindle motor 171 has to include a thrust magnet (not shown) that reduces or counterbalances an axial force which is caused by a lifting force occurring during high-speed rotation of the spindle motor 171 and is exerted on a rotor (not shown) of the spindle motor 171 for the purpose of moving the rotor toward the turntable 172, this example may reduce or counterbalance the lifting force even without having a thrust magnet because the chucking spring 134 presses the turntable 172 in a direction that is opposite to a direction of the lifting force. Thus, the chucking structure, not requiring a thrust magnet, lowers manufacturing costs. Although the above example describes a chucking structure without having a thrust magnet, a thrust magnet may be added to the chucking structure in another example.
In addition to the benefit of reducing manufacturing costs, this example may prevent impact noise caused by a collision of the sliding cone 174 against the clamper 132 for chucking because a chucking force of this example is generated by the chucking spring 134 that smoothly presses the clamper 132 on the spindle 143, not by magnetic force. In other words, because the optical disc 1 and the turntable 172 spontaneously push up the clamper 132 as the spindle unit 170 ascends, impact noise does not occur. In addition, because the chucking spring 134 elastically biases the clamper 132 toward the turntable 172, the clamper 132 applies an appropriate pressure to the optical disc 1 to firmly fix the optical disc on the turntable 172. That is, when the clamper 132 applies a load to the turntable 172 in a direction from top to bottom of the spindle unit 170 to chuck the optical disc 1 on the turntable 172, the clamper 132 presses the optical disc 1, and at the same time, the sliding cone 174 is inserted into the center hole 1a due to appropriate elasticity provided by the elastic member 175 and keeps a concentric arrangement between the optical disc 1 and the spindle motor 171. Thus, the optical disc 1 may be stably rotated during high-speed rotation without vibration.
In the spindle unit 170, the sliding cone 174 includes the bump 174e having the concave portion 174f at a center thereof. Referring to
To solve the above problems, a diameter of the oblique outer circumferential surface 174d may be made sufficiently small. However, the insert protrusion 132c of the clamper 132c may still be misaligned with the concave portion 174f of the sliding cone 174 when the spindle unit 170 ascends because the center hole 1a of the optical disc 1 has a large range of variations in position during a chucking operation.
Accordingly, as an embodiment of the present invention, the sliding cone 174 includes the bump 174e projecting upward on the top surface 174c thereof and the concave portion 174f formed at the center of the bump 174e. In this case, even if the sliding cone 174 is pushed down for the above-described reasons, the insert protrusion 132c may remain inserted into the concave portion 174f due to a sufficient depth of the concave portion 174f, thereby allowing a stable chucking operation.
The bump 174e may have a diameter D1 less than a diameter D2 of the top surface 174c of the sliding cone 174. Because the second mounting surface 122 for the optical disc 1 having a diameter of 8 cm is recessed downward from the first mounting surface 121, a distance between the optical disc 1 that is 8 cm in diameter and the sliding cone 174 is less than a distance between the optical disc 1 that is 12 cm in diameter and the sliding cone 174. Therefore, when the spindle unit 170 ascends during loading of the tray 120, an edge 174g of the top surface 174c of the sliding cone 174 may interfere with a bottom surface of the tray 120 or of the optical disc 1 mounted on the second mounting surface 122 if the entire top surface 174c of the sliding cone 174 protrudes upward. The interference may damage the sliding cone 174 and the optical disc 1. Furthermore, the interference with the sliding cone 174 may cause the optical disc 1 to detach from the second mounting surface 122, thereby resulting in a chucking failure. Referring to
For example, the extent to which the bump 174e protrudes from the top surface 174c of the sliding cone 174 may be 0.1 mm or more. Alternatively, the extent may be about 0.5 mm or more in order to stably chuck a 1.5 t disc. For example, a minimum distance between an edge of the bump 174e and the bottom surface of the optical disc 1 may be determined as about 0.3 mm or more.
While this disclosure includes specific examples, it will be apparent to one of ordinary skill in the art that various changes in form and details may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only, and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if the described techniques are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined in a different manner and/or replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure is defined not by the detailed description, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2013-0013079 | Feb 2013 | KR | national |
