Source: http://www.google.com/patents/US6741419?dq=7,403,220
Timestamp: 2016-05-01 05:15:40
Document Index: 786182563

Matched Legal Cases: ['art 6', 'art 6', 'art 17', 'art 17', 'art 18', 'art 19', 'art 18', 'art 19', 'art 19', 'art 18', 'art 18', 'art 18', 'art 19', 'art 18', 'art 17', 'art 17', 'art 18', 'art 19', 'art 21', 'art 17', 'art 18', 'art 18', 'art 18', 'art 18', 'art 19', 'art 21', 'art 17', 'art 18', 'art 19', 'art 21', 'art 17', 'art 18', 'art 19', 'art 19', 'art 18', 'art 21', 'art 18']

Patent US6741419 - Disk rotation driving apparatus in which a disk-like recording medium is ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsA base of an arm having a driving projection at its tip is rotatably supported on a turn table. The turn table is provided with a first guide part and a second guide part, an outer edge part of the base of the arm and a first guide part are in contact with each other at a contact point, and a projection...http://www.google.com/patents/US6741419?utm_source=gb-gplus-sharePatent US6741419 - Disk rotation driving apparatus in which a disk-like recording medium is centered on a turn tableAdvanced Patent SearchPublication numberUS6741419 B2Publication typeGrantApplication numberUS 10/217,077Publication dateMay 25, 2004Filing dateAug 12, 2002Priority dateAug 15, 2001Fee statusLapsedAlso published asCN1231910C, CN1402237A, DE60209838D1, DE60209838T2, EP1288938A1, EP1288938B1, US20030035244Publication number10217077, 217077, US 6741419 B2, US 6741419B2, US-B2-6741419, US6741419 B2, US6741419B2InventorsTomokuni WaukeOriginal AssigneeAlps Electric Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (5), Classifications (4), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetDisk rotation driving apparatus in which a disk-like recording medium is centered on a turn table
US 6741419 B2Abstract
A base of an arm having a driving projection at its tip is rotatably supported on a turn table. The turn table is provided with a first guide part and a second guide part, an outer edge part of the base of the arm and a first guide part are in contact with each other at a contact point, and a projection and a second guide part are in contact with each other at a contact point. While the arm rotates in a counterclockwise direction, the contact points are moved, and it is possible to prevent the center of the driving projection from largely deviating from a reference normal. Thus, even if a hub in which the position of the driving hole is shifted is mounted, the hub is not largely shifted in a rotation direction relative to a turn table.
What is claimed is: 1. A disk rotation driving apparatus comprising a turn table on which a hub provided on a disk, a center shaft projecting at a rotation center part of the turn table, a driving projection projecting from the turn table at a position separate from the center shaft, and a motor driving part for rotating and driving the turn table, wherein:
an arm including the driving projection at a tip and a rotatably supported base is provided on the turn table, the turn table is provided with a first guide part with which an outer edge part of the base of the arm comes in contact, and a second guide part which is positioned at an inner peripheral side relative to the first guide part and with which an inner edge part of the base of the arm comes in contact, and when a line connecting a center Od of the driving projection when the arm is at a predetermined rotation position and a center of the center shaft is made a reference normal R0, and an arc passing through the center Od of the driving projection and having a rotation center O of the arm as a center is denoted by D0, shapes of the first guide part and the outer edge part, and shapes of the second guide part and the inner edge part are determined so that when a moment in a direction in which the driving projection goes away from the center shaft is exerted on the arm, the center Od of the driving projection is moved to a side of the reference normal R0 rather than the arc D0. 2. A disk rotation driving apparatus as set forth in claim 1, wherein the shapes of the first guide part and the outer edge part, and the shapes of the second guide part and the inner edge part are such that when the moment in the direction in which the driving projection goes away from the center shaft is exerted on the arm, the rotation center O of the arm is moved toward an outer peripheral side of the reference normal R0.
3. A disk rotation driving apparatus as set forth in claim 1, wherein one of the outer edge part of the arm has a convex curve shape directed toward an outer peripheral direction and the first guide part has a convex curve shape directed toward an inner peripheral direction, and an angle between the first guide part and the second guide part is determined so that when the moment in the direction in which the driving projection goes away from the center shaft is exerted on the arm, a contact point A between the first guide part and the outer edge part is moved toward an outer peripheral side of the reference normal R0.
4. A disk rotation driving apparatus as set forth in claim 1, wherein the first guide part and the second guide part face each other such that an interval is gradually increased toward a downstream side in a rotation direction of the turn table.
5. A disk rotation driving apparatus as set forth in claim 1, wherein when the center shaft enters a center hole of the hub, and the driving projection enters a driving hole of the hub to rotate the turn table, a resistance torque generated by sliding between the first guide part and the outer edge part and sliding between the second guide part and the inner edge part is smaller than the moment given from the driving hole to the driving projection.
The present invention relates to a disk rotation driving apparatus in which a hub provided at the center of a disk-like recording medium, such as a floppy disk, is centered on a turn table.
When a disk is loaded, the center shaft 1 of the turn table is inserted into the center hole 5 of the hub, and almost concurrently with this, the disk is held by a magnetic head. At the point of time when the turn table starts to rotate in a clockwise direction (CW), the turn table rotates in the clockwise direction earlier than the hub because of the frictional resistance between the disk and the magnetic head, and at this time, the driving projection 4 enters the driving hole 6 of the hub. Thereafter, although the hub, together with the turn table, is rotated in the clockwise direction, since the hub receives the frictional resistance, the driving projection 4 receives a pressing force F1 in a tangential direction by a side edge 6 a of the driving hole 6.
The moment M1 in the counterclockwise direction is given to the arm 2 by this pressing force F1, and a force F2 toward the outside in a radius direction is given by this moment M1 from the driving projection 4 to an outer peripheral edge 6 b of the driving hole 6. The hub is pressed upward in the drawing by the force F2, so that two side edges 5 a and 5 b of the center hole 5 of the hub are pressed to the center shaft 1, and in this state, positioning between the turn table and the hub is performed.
For example, as shown in FIG. 7, it is assumed that the outer edge part 6 b of the driving hole 6 is shifted to a position denoted by symbol 6 b 1 toward the outer peripheral side relative to the center hole 5. At this time, since the arm 2 rotates with the shaft 3 as a fulcrum, a press contact point Pa between the driving projection 4 and the outer edge part 6 b of the driving hole 6 is moved on an arc locus Da with the shaft 3 as the center, and the press contact point is moved to Pb. As a result, a contact point between the driving projection 4 and the side edge 6 a of the driving hole 6 is shifted from Ta to Ta1 by a distance δ.
Thus, as compared with the normal positioning state, the hub is positioned on the turn table in a state where it is rotated in the counterclockwise direction by approximately δ. When the signal indicating the lead-in position is recorded on the disk with the index pulse as the reference, the lead-in position of this disk becomes different from the lead-in position of another disk, and the compatibility of the disks can not be kept.
The present invention solves the foregoing conventional problems, and has an object to provide a disk rotation driving apparatus in which even if there is a deviation in a relative position between a center hole of a hub and a driving hole, when a turn table and the hub are positioned, a shift of the hub in a rotation direction can be made minimum, or the shift can be eliminated.
According to the present invention, a disk rotation driving apparatus comprises a turn table on which a hub provided in a disk is placed, a center shaft projecting at a rotation center part of the turn table, a driving projection projecting from the turn table at a position separate from the center shaft, and a motor driving part for rotating and driving the turn table, and is characterized in that
an arm including the driving projection at a tip and a rotatably supported base is provided on the turn table,
the turn table is provided with a first guide part with which an outer edge part of the base of the arm comes in contact, and a second guide part which is positioned at an inner peripheral side relative to the first guide part and with which an inner edge part of the base of the arm comes in contact, and
when a line connecting a center Od of the driving projection when the arm is at a predetermined rotation position and a center of the center shaft is made a reference normal R0, and an arc passing through the center Od of the driving projection and having a rotation center O of the arm as a center is denoted by D0,
shapes of the first guide part and the outer edge part, and shapes of the second guide part and the inner edge part are determined so that when a moment in a direction in which the driving projection goes away from the center shaft is exerted on the arm, the center Od of the driving projection is moved to a side of the reference normal R0 rather than the arc D0.
For example, the shapes of the first guide part and the outer edge part, and the shapes of the second guide part and the inner edge part are such that when the moment in the direction in which the driving projection goes away from the center shaft is exerted on the arm, the rotation center O of the arm is moved toward an outer peripheral side of the reference normal R0.
Besides, the outer edge part of the arm has a convex curve shape directed toward an outer peripheral direction, or the first guide part has a convex curve shape directed toward an inner peripheral direction, and an angle between the first guide part and the second guide part is determined so that when the moment in the direction in which the driving projection goes away from the center shaft is exerted on the arm, a contact point A between the first guide part and the outer edge part is moved toward the outer peripheral side of the reference normal R0.
The present invention is contrived such that when the driving hole of the hub pushes the driving projection and the moment is exerted on the arm, the driving projection can be moved along the reference normal R0 to the utmost degree. Thus, even if there is a positional shift between the driving hole of the hub and the center hole, the hub and the turn table can make a relative positional shift in a rotation movement direction minimum.
FIG. 1 is a plan view showing a disk rotation driving apparatus of the invention, FIG. 2 is a sectional view along its center line, FIG. 3 is a sectional view along line III—III of FIG. 1, FIG. 4 is an enlarged view showing a support state of an arm, and FIG. 5 is an enlarged view showing a contact state between a base of the arm and a guide part and in which part of FIG. 4 is further enlarged.
As shown in FIG. 3, holes 13 a and 13 b are formed in the support disk 13 at positions separate from the center shaft 12, and holes 14 a and 14 b are also formed in the attachment disk 14 positioned thereon.
An arm 15 is provided in the turn table 11. This arm 15 is made of synthetic resin or the like, a driving projection 16 projecting upward is integrally formed at its tip, and a rotation reference part 17 is integrally formed at a base. The arm 15 is positioned under the support disk 13, the driving projection 16 extends upward through the hole 13 a of the support disk 13 and the hole 14 a of the attachment disk 14, and the driving projection 16 is projected upward from the surface of the attachment disk 14.
The rotation reference part 17 extends upward through the hole 13 b formed in the support disk 13, and is placed on the support disk 13 in the hole 14 b of the attachment disk 14. Thus, the hole 14 b of the attachment disk 14 is a support part for rotatably supporting the base of the arm 15.
As shown in FIG. 1, two inner surfaces of the hole 14 b of the attachment disk are a first guide part 18 and a second guide part 19. The first guide part 18 is positioned at an outer peripheral side and is formed to be linear, and the second guide part 19 is also formed to be linear. The second guide part 19 is formed at an inner peripheral side of the first guide part 18 to have a predetermined opening angle with respect to the first guide part 18. The first guide part 18 and the second guide part 19 are taper-shaped so that the opposed interval gradually becomes wide toward the downstream side of a rotation direction (CW) of the turn table.
The metal hub 30 is provided at the center of the flexible disk such as a floppy disk, and as shown in FIG. 1, a rectangular center hole 31 is bored in the center of the hub 30, and two positioning edges 31 a and 31 b are provided in the center hole 31. A driving hole 32 is bored at a position separate from the center hole 31 of the hub 30. A side edge 32 a of the driving hole 32 positioned at the downstream side in the rotation direction and an outer peripheral edge 32 b form a positioning part coming in contact with the driving projection 16.
FIG. 4 shows a state in which the hub 30 having the center hole 31 and the driving hole 32 adapted for a standard is positioned at the center shaft 12 and the driving projection 16. When the center of a cylindrical shape of the driving projection 16 in this state is denoted by Od0, a line connecting the center Oc of the center shaft 12 and the center Od0 of the driving projection 16 is made a reference normal R0. At this time, the first guide part 18 is parallel to the reference normal R0.
When the turn table 11 is further rotated in the clockwise direction, since the hub 30 receives the frictional resistance, the driving projection 16 is pressed to the side edge 32 a of the driving hole 32. In FIG. 4, a reaction force in the tangential direction of the disk, exerted on the center Od0 of the driving projection 16 from the side edge 32 a is expressed by a pressing force Fv.
By the pressing force Fv in the tangential direction, a moment Ma with the rotation reference part 17 as the rotation center and in the counterclockwise direction is exerted on the arm 15. By this moment Ma, the driving projection 16 gives an outward pressing force Fh in the radial direction to the outer peripheral edge 32 b of the driving hole 32. The outer peripheral edge 32 b of the driving hole 32 is pressed outward in the radial direction by the pressing force Fh, so that the two positioning edges 31 a and 31 b of the center hole 31 of the hub 30 are pressed to the center shaft 12, and the turn table 11 and the hub 30 are positioned.
Although the hub 30 is manufactured by press molding or the like, there is a definite tolerance in the molding size of the hub for each floppy disk, and as a result, there is fluctuation in the relative position between the center hole 31 and the driving hole 32, and there is also fluctuation in the size of the driving hole 32. FIG. 4 shows a case where the position of the outer peripheral edge 32 b of the driving hole 32 is shifted to the outer peripheral side, and is formed at a position 32 b 1. At this time, by the moment Ma, the arm 15 is slightly rotated in the counterclockwise direction until the driving projection 16 strikes against the outer edge part at the position 32 b 1.
Since this embodiment is structured such that the contact points between the rotation reference part 17 of the arm 15 and the first guide part 18 and between that and the second guide part 19 are changed in accordance with the rotation position of the arm 15, when the arm 15 is rotated in the counterclockwise direction, contact point T1 between the side edge 32 a of the driving hole 32 and the driving projection 16 is not extremely moved in the counterclockwise direction.
As described above, when the arm 15 is rotated in the counterclockwise direction, the contact point A between the outer edge part 21 of the rotation reference part 17 of the arm 15 and the first guide part 18 is moved along the first guide part 18 parallel to the reference normal R0 toward the outer peripheral direction of the disk, and the rotation center O of the arm 15 is also moved along the first guide part 18 toward the outer peripheral direction of the disk. Thus, when the arm 15 is rotated in the counterclockwise direction, as shown in FIG. 4, the center of the driving projection 16 does not deviate from the reference normal R0 largely as indicated by Od0 to Od1, and is moved toward the outer peripheral direction.
Thus, in FIG. 4, when the center of the driving projection 16 at the time when the arm 15 is in the state of the solid line is denoted by Od0, and an arc passing through the center Od0 of the driving projection 16 with the rotation center O0 of the arm 15 at this instant as the center is denoted by D0, when the arm 15 is rotated in the counterclockwise direction from this state, the center Od of the driving projection 16 is moved at least outside of the arc DO and toward the outer peripheral direction along the reference normal R0.
Accordingly, as shown in FIG. 4, even if the outer peripheral edge 32 b of the driving hole 32 is formed at the position 32 b 1 because of the tolerance of parts or the like, and as a result, the arm 15 is rotated in the counterclockwise direction from a regular position, the center of the driving projection 16 does not deviate largely from the reference normal R0. That is, even if the press contact point between the driving projection 16 and the outer peripheral edge 32 b is changed from P1 to P2, the press contact point P2 does not deviate largely from the reference normal R0, and accordingly, the contact point T1 between the side edge 32 a of the driving hole 32 and the driving projection 16 does not shift largely, and the positions of the hub 30 and the turn table 11 do not shift largely in the rotation direction.
Besides, when the directions of the first guide part 18 and the second guide part 19, and the radius of curvature of the arc of the outer edge part 21 are suitably set, it is also possible that when the arm 15 is rotated, the center Od of the driving projection 16 can also be always moved on the reference normal R0.
In the driving apparatus of the floppy disk or the like, at the timing of the index pulse obtained from the pulse generator provided in the motor driving part, the signal indicating the lead-in position is written in the disk. In the disk rotation driving apparatus, even if the relative position between the center hole 31 of the hub 30 and the outer peripheral edge 32 b of the driving hole 32 is changed, since the position shift of the hub 30 in the rotation direction with respect to the turn table 11 is small, or the position shift can be almost eliminated, even when the hub 30 with any size is loaded, it becomes possible to always write the signal to the disk at an approximate position or the same position, and the compatibility of the disk can be secured.
The center Od0 of the driving projection 16 is in the state where it is indicated by the solid line in FIG. 4, the rotation center of the arm 15 at that instant is denoted by O0, and the distances between the center Od0 and the rotation center O0 on the rectangular coordinates are respectively denoted by W0 and L0. When a pressing force given from the side edge 32 a of the driving hole 32 to the center Od0 of the driving projection 16 is denoted by Fv, when frictional coefficient is denoted by μ0, a frictional reaction force exerted on the contact point T1 between the side edge 32 a of the driving hole 32 and the driving projection 16 is μ0�Fv. Besides, a pressing force given from the center Od0 of the driving projection 16 to the outer peripheral edge 32 b of the driving hole 32 is denoted by Fh, and a frictional resistance torque between the rotation reference part 17 of the base of the arm 15, and the first guide part 18 and the second guide part 19 is denoted by r.
At this time, if an inequality of the following numerical expression 1 is established, the positioning edges 31 a and 31 b of the center hole 31 can be pressed to the center shaft 12 by the pressing force Fh, and the hub 30 can be positioned on the turn table 11. Here, Rd denotes a radius of the cylindrical shape of the driving projection 16.
W 0 �Fh>μ 0 �Fv(Wo+Rd)+r [Numerical expression 1]
Incidentally, as shown in FIGS. 4 and 5, when a pressing reaction force exerted on the contact point A between the outer edge part 21 of the rotation reference part 17 of the base end part of the arm 15 and the first guide part 18 is denoted by fv, its frictional force is denoted by μ�fv, a pressing reaction force exerted on the contact point B between the projection 22 of the inner peripheral edge and the second guide part 19 is denoted by fh, its frictional force is denoted by μ�fh (μ denotes a coefficient of static friction), distances of the contact point A and the contact point B on the rectangular coordinates are respectively denoted by x and y, and an inclination angle of the second guide part 19 with respect to a perpendicular line of the first guide part 18 is denoted by α, the frictional resistance torque r is expressed by the following numerical expression 2.
r=y�μ�fh�cos α−x�fh�cos α+x�μ�fv+y�fv [Numerical expression 2]
Even in such shapes, when the arm 15 is rotated in the counterclockwise direction, the contact point between the outer edge part 21A and the first guide part 18A can be moved along the reference normal R0 toward the outer peripheral direction as indicated by A0, A11 and A12, and accordingly, the rotation center of the arm can also be moved along the reference normal R0 as shown in FIG. 5. Thus, even if the position of the outer peripheral edge 32 b of the driving hole 32 of the hub 30 is shifted, when the hub is positioned, a large position shift between the turn table 11 and the hub 30 in the rotation direction can be prevented.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5126900 *Nov 5, 1990Jun 30, 1992Sony CorporationDisk gripping deviceUS5151836 *Mar 21, 1991Sep 29, 1992Alps Electric Co., Ltd.Disk chucking deviceUS5701217Jul 31, 1996Dec 23, 1997Seiko Epson CorporationDisk chucking mechanism and drive pin structure having chucking lever movable in two degrees of freedomUS6208487Sep 1, 1999Mar 27, 2001Alps Electric Co., Ltd.Floppy disc drive chucking deviceEP1061512A2May 30, 2000Dec 20, 2000Alps Electric Co., Ltd.FDD chucking device* Cited by examinerClassifications U.S. Classification360/99.05International ClassificationG11B17/028Cooperative ClassificationG11B17/0282European ClassificationG11B17/028DLegal EventsDateCodeEventDescriptionAug 12, 2002ASAssignmentOwner name: ALPS ELECTRIC CO., LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:WAUKE, TOMOKUNI;REEL/FRAME:013191/0045Effective date: 20020729Oct 15, 2007FPAYFee paymentYear of fee payment: 4Jan 9, 2012REMIMaintenance fee reminder mailedMay 25, 2012LAPSLapse for failure to pay maintenance feesRotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services