JPS63206954A - Support mechanism for rotary part of magnetic disk device - Google Patents

Abstract

PURPOSE:To obtain a magnetic disk device which excels in the information writing/reading reliability by using a specific rotary part support mechanism. CONSTITUTION:Two support points 22a are provided at the inner circumference of a sleeve 22 in order to support a ball bearing 24 pressed by a spring 26. A center angle theta formed by both points 22a against the load direction (arrow head F) of the spring 26 is set at about 60 deg.. Then a rotary support part 2 sets the relation of arm groups 3 so that the pressing direction (arrow head F) of the spring 26 is set rectangular to the seeking direction (arrow head S) of a magnetic head. Thus the oscillating motions of a rotor can be eliminated and therefore the stable and accurate revolutions of the rotor are secured. At the same time, the satisfactory resistance force is secured even to the external force applied in the direction rectangular to the pressing direction to the bearing 24. Then the high information writing/reading reliability is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a support mechanism for a rotating part such as a spindle motor in a magnetic disk device, a stepping motor for a positioning device, or a rotary magnetic head positioning device.

[Conventional technology]

In a magnetic disk device, a stepping motor and a magnetic head are used to drive a spindle motor that carries and rotates a magnetic disk, a magnetic head positioning device that moves and positions a magnetic head on a predetermined track of a magnetic disk, and a magnetic head. Among positioning devices, a support mechanism for a rotating portion of a rotary magnetic head positioning device that performs a positioning operation by rotational movement of an arm carrying a magnetic head has the following basic configuration.

That is, as shown in Fig. 1 (Fig. 1 is a drawing of an embodiment of the rotating part support mechanism of the present invention, the basic structure except for the detailed structure is the same as the conventional rotating part support mechanism. Therefore, ball bearings 23 and 24 are attached to the lower and upper ends of a shaft 28 whose end is fixed to the substrate 21, and these balls The bearing is fitted into and supported by the inner surface of the sleeve 22. One of the two ball bearings (the lower ball bearing 23 in FIG. 1) has its inner ring attached to the shaft 28,
The other ball bearing (in the case of FIG. 1, the upper ball bearing 24) has its inner ring fixed to the shaft 28, while its outer ring is fixed to the sleeve 22. By suppressing this from below with a spring 25, the play between the balls and the inner and outer races of these two ball bearings is eliminated, allowing precise and stable rotation of the sleeve 22. It has a structure that guarantees it.

Little one, the outer ring of the ball bearing 24 and the sleeper 22
There is a slight play between the ball bearing 24 and the sleeve 22, and the size of the play is such that when the environmental temperature in which the magnetic disk drive is used changes, the temperature expansion coefficient due to the difference in the materials of the ball bearing 24 and the sleeper 22 changes. The magnetic disk or magnetic head that is held by this rotational support mechanism and performs a rotational motion causes a whirling motion, which changes depending on the environmental temperature.

In order to prevent such whirling motion of the rotating part, the rotating part support mechanism of a conventional magnetic disk drive employs a detailed configuration as illustrated in FIG. 4. (Tokkai 1986-
1391 45 (60.7.23), patent application Sho 6O-i1
3503 (60-5, 27)) In other words, an annular groove having a center at a position offset by a distance δ from the central axis is provided on the inner surface of the sleeve 32, and the O-ring 3 is attached to the sleeve 32.
6 (shown with diagonal lines in Figure 4, and other parts are shown with diagonal lines omitted), and an acute angle α is formed on both sides of the eccentric shaft with respect to the direction of (reference mark F). Two protrusions 32a are provided at the position, and the ball bearing 34 is held at three points: the OIJ ring 36 (the contact point is reference numeral 36a) and these two protrusions 32a, and the pressing force of the O ring 36 is constantly maintained. By configuring it to be attached to the ball bearing 34, the above-mentioned whirling motion is prevented and stable rotational motion is always performed.

The conventional rotating part support mechanism described above is effective in maintaining stable rotation of the rotating body by eliminating the play between the ball bearing and the sleeve that supports it, but the pressing force caused by the O-ring is There is a problem in that it does not necessarily have sufficient resistance when an external force is applied in a direction perpendicular to the direction (reference numeral F in FIG. 4). That is, in FIG. 4, the protrusion 32a generally has a considerable width, and its center is set to form an acute angle α with the center line CL.
The contact point between the ball bearing 34 and the protrusion 32a is the end point P of the center line CLWD of the protrusion 32a, and therefore the central angle β is smaller than α. central angle β
When the value of is small, the resistance force against external force (force due to external vibration, etc.) applied in the direction perpendicular to the direction of arrow F is small. Therefore, if external vibration is transmitted during positioning operation of the magnetic head, positioning error will be reduced. This causes an error in writing or reading information. Furthermore, depending on the machining accuracy of the protruding portion 32a, there is a problem that the left and right center angles may not be equal, or may vary from product to product, resulting in unstable quality.

[Problem that the invention seeks to solve]

The problem to be solved by the present invention, in other words, the purpose of the present invention is to eliminate the drawbacks of the rotating part support mechanism of the conventional magnetic disk device as described above, and to eliminate the whirling motion of the rotating body to stabilize it. In addition to ensuring accurate rotation, it also has sufficient resistance against external forces applied in a direction perpendicular to the direction in which pressure is applied to the ball bearing, making it possible to write and read information with high reliability. An object of the present invention is to provide a rotating part support mechanism for a magnetic disk device.

[Means for solving problems]

A rotating part support mechanism for a magnetic disk device according to the present invention includes a shaft whose end is fixed to a substrate, two ball bearings whose inner rings are fixed to the upper and lower ends of the shaft, and the two ball bearings. a sleeve whose inner peripheral surface is supported by an outer ring of the sleeve, the outer ring of one of the two ball bearings is fixed to the inner peripheral surface of the sleeve, and the other ball bearing is fixed to the inner peripheral surface of the sleeve. The outer ring of the ball bearing has a play space between it and the inner peripheral surface of the sleeve, and is pressed upward by a compression spring. The sleeve has two bearing support points on its inner peripheral surface, and the bearing support points are symmetrical with respect to the pressing direction of the spring member and at the center thereof. The corners are 60'',
The pressing direction of the spring member is set perpendicular to the direction of positioning movement of the magnetic head.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 3 is an exploded perspective view showing the configuration of an embodiment of a rotary magnetic head positioning device to which the present invention is applied, and FIG.
FIG. 2 is a cross-sectional view taken along line X-X in FIG.

Referring to FIG. 3, arm #3, which has a magnetic head 8 mounted on its tip, is attached to a rotating support section 2 (details will be described later).
The coil 4 attached to the rear part of the coil 4 cooperates with the magnetic circuit 5 disposed corresponding to the coil 4 to provide rotational motion, and the magnetic head 8 performs a positioning operation (seek) in the direction of arrow S. is configured to perform an action).

The arm group 3 is fixed by inserting an internal hole provided at the rear of each arm into the sleeve of the rotary support section 2 and fixing the arm group 3 by a fixing ring 6 and a presser plate 7.

As shown in FIG. 2, the rotation support section 2 has ball bearings 23 and 24 mounted on the lower and upper ends of a shaft 28 whose end is fixed to a base plate 21. The bearings 23 and 24 support the sleeve 22 by fitting it on the outside thereof. The inner rings of the ball bearings 23 and 24 are both fixed to the shaft 28, and the outer ring of the ball bearing 23 is also fixed to the inner periphery of the sleeve 22. There is a slight play between the compression spring (spring) 2 from below.
It is pressed by 5. Therefore, this spring 2
5 eliminates the play between the inner and outer rings of the ball bearings 23 and 24 and the balls, so the sleeper 22 can perform precise and stable rotational movement around the fixed shaft 28. Can be done.

As mentioned above, the vertical play between the ball bearings 23 and 24 is removed by the force of the spring 25, but the horizontal play between the ball bearing 24 and the sleeve 22 is removed by the compression spring 26. remove.

That is, a hole into which a spring 26 is inserted is provided on the side surface of a portion of the sleeve 22 that corresponds to the ball bearing 24, and the spring 26 is inserted into this hole and blocked on the outside by a stop plate 27, thereby locking the ball into place. bearing 24
The outer ring of is pressed horizontally. The stop plate 27 is fixed to the sleeve 22 by a known fixing means such as screws or adhesive.

FIG. 2 is a sectional view taken along the line XX in FIG. 1, showing details of the relationship between the sleeper 22, the ball bearing 24, and the spring 26.

As shown in FIG. 2, two support points 22a are provided on the inner periphery of the sleeve 22 to support the ball bearing 24 pressed by the spring 26. The central angle θ formed by these support points 22a with respect to the spring loading direction (arrow F) is set to approximately 60°. Therefore, the ball bearing 26 is connected to the spring 2
It is supported by three points: 6 and two supporting points 22a, and always maintains a constant posture. Therefore, there is no wobbling movement in the rotational movement of the sleeper 22, and accurate and stable rotational movement can be performed. On the other hand, when receiving an external force in a direction perpendicular to the arrow F, a resistance force against this is generated at the support point 22a and the force is received. According to the calculation,
Since it can withstand up to three times the pressing force of the spring 26, it can sufficiently resist external forces.

The rotation support part 2 configured as described above has a spring 26
The pressing direction (arrow F) is the theta direction of the magnetic head (
The relationship between the arm group 3 and the arm group 3 is set so that it is perpendicular to the arrow S) in FIG. By assembling a magnetic disk drive to satisfy these conditions, even if the environmental temperature changes and the inclination of the shaft 28 changes due to the difference in expansion coefficient between the ball bearing 24 and the sleeper 22,
It does not affect the positioning of the magnetic head 8, and therefore reliability in writing and reading information can be maintained. In addition, even when an external force such as vibration acts in the theta direction, a large drag force acts against it as described above, so the vibration etc. is not transmitted to the positioned magnetic head, thereby ensuring stability of positioning. can do.

The above embodiment is an example in which the present invention is applied to a rotary magnetic head positioning device for a magnetic disk drive. 3
The illustrated embodiment uses a voice coil motor with a coil and a magnetic circuit as the drive source of the positioning device, but the same applies to other models that use a stepping motor instead of the voice coil motor.

The embodiments described above also use compression springs as spring members to press the ball bearings in the horizontal direction;
It is obvious from the above description that there is no problem even if the rigid O-ring illustrated in FIG. 4 is used.

〔Effect of the invention〕

As explained in detail above, by using the rotating part support mechanism of the magnetic disk drive of the present invention, precise and stable rotational movement without whirling movement can be achieved, and the magnetic head can be moved even when the environmental temperature changes. This has the effect of providing a rotating part support mechanism that can perform stable positioning operations because it has no effect on the positioning operation and has a large resistance to external forces such as vibrations. By adopting the rotating part support mechanism of the invention,
This has the effect of providing a magnetic disk device with excellent reliability in writing and reading information.

[Brief explanation of the drawing]

Fig. 1 is a Y-Y sectional view showing details of the rotation support part in Fig. 3, Fig. 2 is a XX sectional view in Fig. 1, and Fig. 3 is an application of the present invention to a rotary magnetic head positioning device. FIG. 4 is an exploded perspective view showing the configuration of the ninth embodiment, and FIG. 4 is a sectional view showing an example of a conventional rotating part support mechanism. In the figure, 2... Rotation support part, 3... Arm group,
4... Coil, 5... Magnetic circuit, 6.
...Fixing ring, 7...Press plate, 8...
...Magnetic head, 21...Substrate, 22...
...Sleep, 23,24...Ball bearing, 25.26...Spring, 27...
...Stopping plate, 28...Shaft.
,,,s...:゛) Agent: Patent Attorney Susumu Uchihara', 4. i' 1st
Times\J Z Figure

Claims (1)

[Scope of Claims] A shaft whose end is fixed to a substrate, two ball bearings whose inner ends are bonded to the upper and lower ends of the shaft, and whose inner circumference is defined by the outer rings of the two ball bearings. a sleeve whose surface is supported, an outer ring of one of the two ball bearings is fixed to the inner peripheral surface of the sleeve, and an outer ring of the other ball bearing is fixed to the inner peripheral surface of the sleeve. In a rotating part support mechanism of a magnetic disk drive which has a play between a surface and is pressed upward by a compression spring, a spring member that presses an outer ring of a ball bearing having the play in a horizontal direction from a side surface is provided. The sleeve has two bearing support points on its inner circumferential surface, and the bearing support points are symmetrical with respect to the pressing direction of the spring member and have a central angle of 60°, A rotating part support mechanism for a magnetic disk drive, wherein the pressing direction is perpendicular to the direction of positioning movement of the magnetic head.