JP2610129B2 - Method for setting drive force and action point of drive motor in head positioning device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for setting a driving force and a point of action of a driving motor in a head positioning device of a disk drive.

[Prior Art] FIGS. 3 and 4 show a conventional head positioning device described in Japanese Patent Application Laid-Open No. 58-211363, respectively.
FIG. 3 is a side view showing the disk plate together with the magnet except for the magnet, and FIG. 4 is a front view. In the figure, (1a) and (1b) are left and right permanent magnets that generate magnetic flux, (2a) and (2b) are upper permanent magnets provided on the left and right, (3a) and (3b) are lower permanent magnets,
(4a) and (4b) are left and right yokes provided adjacent to the left and right permanent magnets (1a) and (1b) respectively, (5a) and (5b) are upper yokes provided on the left and right, (6a) (6b) is the lower yoke, (7a) and (7b) are the center yoke, (8a) and (8b)
Is a coil for generating a driving force, and (1) to (8) constitute a driving motor. (9) is a carriage including a head, (10a) and (10b) are left and right support systems, (11) is a center support system, (12) is an actuator for a head objective lens, (13) is an optical disk plate, and (14). Is an optical disk board (1
The optical disk plate (13) rotates around the center of the motor (14). (15) is a rail, arrows A1 and A2 are moving directions of the head positioning device, arrow A1 is a forward direction toward the center of the optical disk plate (13), and arrow A2 is a backward direction.

The driving force for moving the carriage (9) will be described using, for example, the driving motor on the left side in FIG. The magnetic flux generated by the permanent magnets (1a), (2a) and (3a) interlinks with the coil (8a), and the center yoke (7a), the side yoke (not shown), the upper yoke (5a), and the lower yoke (6a), the magnetic path is configured to pass through the left yoke (4a) and return to the permanent magnet. The same applies to the drive motor on the right side of the carriage (9), and the drive force is generated at the portion where the coil and the magnetic flux link. The carriage (9) is supported (10
a), (10b) and (11) are smoothly supported in the movement direction (arrows A1 and A2 directions), and the coils (8a) and (8b)
The head can be positioned at a desired position on the disk plate (13) by linearly reciprocating on the rail (15) by the driving force generated in (1). In the case of an optical disk device, after positioning the head, a light beam is incident on the disk plate (13) from the actuator (12) to write or read information. Therefore, the movable part includes the carriage (9), the actuator (12), the left and right support systems (10a) and (10b), the coils (8a) and (8b), and the center yokes (7a) and (7b).
Becomes In order for the right and left driving forces to work efficiently, it is necessary to bring the point of application of the driving force on the center of gravity of the moving part in the moving direction.

[Problems to be Solved by the Invention] In the conventional head positioning device as described above, the drive motors are simply mounted at symmetrical positions on both sides of the carriage, and as a result, the resultant force of the center of gravity axis of the movable portion and both drive motors is obtained. It only discloses that the axes of action coincide. Therefore, when the center of gravity axis of the movable portion is shifted from the center of the carriage and becomes an asymmetric position due to the mounting of the head or the like,
It is necessary to correct the center of gravity of the movable part to a symmetrical position by adding an auxiliary mass to the carriage, or to adjust the driving force of the drive motors and to adjust the positional relationship between each drive motor and the carriage. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and in a real individual positioning device, a drive motor capable of reliably matching the center of gravity of the movable portion with the point of application of the driving force. It is an object of the present invention to obtain a method of setting the driving force and the action point of the motor.

[Means and Actions for Solving the Problems] In a method for setting a driving force and an action point of a driving motor in a head positioning apparatus according to the present invention, a driving motor including a coil and a magnet is provided on both sides of a carriage, and the driving motor extends along a moving direction. Intersections of the center of gravity of the movable part and the axis of action of the driving force of the drive motor with the plane perpendicular to the moving direction are defined as the center of gravity of the movable part and the point of action of the drive motor, respectively. An XY coordinate plane with the center of gravity as the origin is set, and each of the drive motors has a plurality of drive force generators, and these drive force generators change their drive forces independently to control the drive motors. The magnitude of the driving force and the position of the action point in the XY plane can be changed, and the driving force of one of the drive motors is K1, and the X and Y coordinates of the action point are P1x and P1. y, when the driving force of each of the other driving motors is K2, and the X and Y coordinates of the action point are P2x and P2y, the driving force and the action point of each of the above driving motors are set so that both of the following equations are satisfied. It is like that.

P1x · K1 + P2x · K2 = 0 P1y · K1 + P2y · K2 = 0 In this case, the driving forces of the driving force generating units, which are the constituent units of each driving motor, are mutually changed, so that the driving forces of the plurality of driving force generating units are combined. It is possible to adjust the magnitude of the driving force as the driving motor as the force and the position of the point of action. As a result, both formulas can be satisfied at the same time without taking any complicated means such as changing the positional relationship between the drive motor and the carriage with respect to the center of gravity of the movable portion arbitrarily determined. The axis of the combined action of the driving force of the motor and the axis of the center of gravity of the movable part completely match, and extremely smooth and efficient movement characteristics of the carriage can be obtained.

Further, by changing the number of turns of the coil of the drive motor, the number of magnetic fluxes interlinking with the coil changes, and the magnitude of the driving force of the drive motor can be changed. It is definitely done.

Also, by changing the air gap magnetic flux density of the magnetic circuit of the drive motor, it is possible to change the magnitude of the driving force of the drive motor, and if this air gap magnetic flux density is changed for each driving force generating unit, The position of the point of application of the driving force of the driving motor can be changed, and the setting for satisfying the above equation is reliably performed.

[Embodiment] FIGS. 1 and 2 show a method of setting a driving force and a point of action of a driving motor in a head positioning apparatus according to an embodiment of the present invention. FIG. FIG. 2 is a front view showing the plate together. In the figure, (1) to (15) show the same or corresponding parts as those of the conventional apparatus, and (16) shows the position where the center of gravity of the moving part in the moving direction intersects a plane perpendicular to the moving direction. And is referred to as the center of gravity. P1 and P2 are points of application of the driving force of the left coil (8a) and the right coil (8b) toward the carriage (9), respectively. That is, in FIG. 2, the intersections between the axes of action of the driving forces of the two coils (8a) and (8b), which are in the direction perpendicular to the plane of the paper, and the plane perpendicular thereto (the plane of the figure) are defined as the action points P1, P2. I do. This point of action (P1),
The driving forces in (P2) are K1 and K2, respectively.

FIG. 5 is an enlarged perspective view showing a driving force generating portion of a driving motor on the left side of FIG. 2 as an example. In the figure, (B1) to (B3) are magnetic fluxes generated by the permanent magnets (1a) to (3a) constituting the driving force generating unit, linked to the coil (8a), and entering the center yoke (7a). is there. When the magnetic fluxes (B1) to (B3) interlink with the current flowing through the coil (8a), a force is generated in the moving direction Z (or -Z) according to Fleming's law.

(K11) to (K13) are driving forces generated by the magnetic fluxes (B1) to (B3), and the magnitude of the driving force generated is determined by, for example, the number of interlinking magnetic fluxes. In FIG. 5, assuming that the magnetic flux density is uniform, each permanent magnet (1
The operating points (P11) to (P13) where the driving forces (K11) to (K13) act in a) to (3a) are the magnetic fluxes (B1) to (B3), respectively.
Occurs near the center of the surface of the interlinking coil. The driving force of the illustrated drive motor becomes these resultant forces (K1).

Next, the position of the action point (P1) where the resultant force (K1) acts will be described. Now, with the action point (P1) as the origin, the X axis,
Take the Y axis as shown. X from action point (P11)-(P13)
Draw the perpendiculars to the axis and the Y axis, and cross each point (P11
X) to (P13X) and (P11Y) to (P13Y), the following equations (1) and (2) hold. Since the coordinate value has the action point (P1) as the origin, the action points (P11X) and (P13Y) are negative values.

P11X / K11 + P12X / K12 + P13X / K13 = 0 (1) P11Y / K11 + P12Y / K12 + P13Y / K13 = 0 (2) The point where the above equations (1) and (2) hold is the position of the action point (P1). This is the point of application of the resultant force (K1).

Therefore, by changing the strength of the permanent magnets (1a), (2a), and (3a) independently, the magnetic flux density of each magnetic circuit is changed, and the point of action can be freely moved up, down, left, and right. be able to. For example, when the strength of the upper permanent magnet (2a) is increased with respect to the lower permanent magnet (3a), the action point (P1) can be moved upward.

Also, without changing the types of the magnets (1a), (2a), and (3a), the magnets (1a), (2a), (3a) and the center yoke (7a)
May be changed.

Next, the positional relationship between the driving forces on both sides and the center of gravity of the movable part will be described. First, the center of gravity axis will be described with reference to FIG. FIG. 6 is an explanatory diagram showing the relationship between the driving force on both sides and the position of the center of gravity of the movable part. The position of the center of gravity of the movable part on the XY plane is defined as G (X, Y). Since the movable part moves along the Z axis, the position viewed from the XY plane does not change, but the center of gravity moves parallel to the Z axis when viewed from the YZ plane. The locus of the center of gravity is called a center of gravity axis. In this embodiment, since the movement is parallel to the Z axis, there is no problem if the point of application of the force is shifted in the Z direction, and the positional relationship between the position of the center of gravity and the point of application of the driving force viewed from the XY plane is considered.

If the point of action of the force obtained by combining the driving forces of the left and right drive motors and the center of gravity position G (X, Y) match, the distance between the position of the center of gravity and the combined point of action becomes zero, so that no moment is generated. No vibration occurs.

Next, conditions for setting the above-mentioned moment to zero will be described. Now, the center of gravity G (X, Y) is set as the origin of the XY coordinates, and the points where the action points (P1) and (P2) intersect with the X-axis and the Y-axis drawn down perpendicularly are P1x, P1y, P2x, and P2y, respectively. I do. Here, P1x and P1y are negative values.

P1x · K1 + P2x · K2 = 0 (3) P1y · K1 + P2y · K2 = 0 (4) The action point (P
1), the positions of (P2) and the magnitudes of the driving forces (K1) and (K2) may be determined.

In this embodiment, the coil (8
a) The three driving forces generated in the driving force generators arranged on the three surfaces of (8b) are independently changed, whereby the driving point of the driving motor as well as the magnitude of the driving force of the driving motor can be freely set. Because it was configured to be able to change, as in the past, without changing the mounting position of the carriage and the drive motor, and without taking additional complicated means such as changing the position of the center of gravity by adding an auxiliary mass, The above (3) and (4) can be reliably established.

In the above embodiment, the driving force of the driving motor is adjusted by changing the air gap magnetic flux density. However, the coil (8) is adjusted so as to satisfy the equations (3) and (4).
The number of turns of a) and (8b) may be changed to change the number of magnetic fluxes interlinking with the coil.

Means for changing each of the numbers of magnetic fluxes (B1) to (B3) include, for example, permanent magnets (1a), (1b), (2
By changing the type and thickness of a), (2b), (3a), and (3b), the magnitude of the magnetic flux density can be changed.

[Effects of the Invention] As described above, according to the present invention, each drive motor has a plurality of drive force generation units, and each of the drive force generation units is configured to independently change its drive force. Since the magnitude of the driving force of each drive motor and the position of the action point in the XY plane are set, it is possible to perform both drive operations without changing the positional relationship between the drive motor and the carriage. The axis of the combined action of the driving force of the motor and the axis of the center of gravity of the movable part can be completely matched,
Extremely smooth and efficient movement characteristics of the carriage can be obtained.

Also, by changing the number of turns of the coil of the drive motor, the number of magnetic fluxes interlinking with the coil changes, and the magnitude of the drive force of the drive motor can be changed. Can be more reliably matched.

Also, by changing the air gap magnetic flux density of the magnetic circuit of the drive motor, the magnitude of the driving force of the drive motor can be changed, and by further changing this air gap magnetic flux density for each driving force generating unit, The position of the point of application of the driving force of the drive motor can be changed, and the combined action axis and the center of gravity axis can be more reliably matched.

[Brief description of the drawings]

1 and 2 are diagrams for explaining a method of setting a driving force of a driving motor and an operation point in a head positioning device according to an embodiment of the present invention. FIG. FIG. 2 is a side view showing the disk plate and the movable part when positioning the magnet, FIG. 2 is a front view showing the magnet together,
3 and 4 each show a conventional head positioning device. FIG. 3 is a side view showing a disk plate and a movable portion when positioning the head with respect to the disk plate.
FIG. 5 is a front view also showing a magnet, FIG. 5 is an explanatory view showing an enlarged portion of a driving force generating portion on one side according to an embodiment of the present invention, and FIG. It is explanatory drawing which shows the force and the center-of-gravity positional relationship of a movable part. (1a), (1b), (2a), (2b), (3a), (3b) ...
Magnet, (8a), (8b) ... coil, (9) ... carriage, (16) ... center of gravity position. In the drawings, the same reference numerals indicate the same or corresponding parts.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor: Manabu Ogura, 8-1-1, Tsukaguchi-Honmachi, Amagasaki City Mitsubishi Electric Corporation Applied Equipment Research Laboratory (56) References JP-A-58-211363 (JP, A) Sho 61-39846 (JP, A) Shokai 62-165772 (JP, U)

Claims (3)

(57) [Claims] 1. A method for setting a driving force and a point of action of a driving motor in a head positioning device for moving a carriage by providing a driving motor with coils and magnets on both sides of the carriage, wherein a center of gravity of the movable portion along the moving direction is provided. The intersection of the axis of action of the drive force of the drive motor and the plane perpendicular to the moving direction is defined as the center of gravity of the movable part and the point of action of the drive motor, respectively, and the center of gravity of the movable part is defined as the origin on the perpendicular plane. Each of the drive motors has a plurality of drive force generating units, and the drive force of each of the drive motors is changed independently by changing the drive force of each of the drive force generators. And the position of the action point in the XY plane can be changed, the driving force of one of the drive motors is K1, and the X and Y coordinates of the action point are P1x and P1y. Each driving force of the other drive motor K2, · P2x the X coordinate · Y coordinate of the point P2y
Wherein the driving force and the operating point of each of the driving motors are set so that both of the following equations are satisfied. A method for setting the driving force and the operating point of the driving motor in the head positioning device . P1x ・ K1 ＋ P2x ・ K2 = 0 P1y ・ K1 + P2y ・ K2 = 0 2. The head positioning device according to claim 1, wherein the magnitude of the driving force of the driving motor is changed by changing the number of turns of the coil. How to set the action point. 3. The method according to claim 1, wherein the magnitude of the driving force of the drive motor or the position of the point of action is changed by changing the air gap magnetic flux density of the magnetic circuit of the drive motor. 3. A method for setting a driving force and an action point of a driving motor in the head positioning device according to claim 2.