JPS6278784A - Head feeding device for magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To reduce the cost of a heat feeding device and also to improve the position accuracy of a magnetic head by supporting a shaft rotatably on at end distant from a position where the shaft interlocks an engaging member provided to a head holding member. CONSTITUTION:In case a shift dr is produced between the rotary center axes of a male screw part 17 and a coupling part 8a of a shaft 8, the shaft 8 is revolved by the revolving power of a motor 5. Thus the axis centers 23 and 24 of the part 17 and the part 8a are turned with angle changes round the points H and G against the rotary center axis B-B of the shaft 8 respectively since a head holding member 2 is controlled by guide shafts 3 and 16 so as to be moved toward an arrow D only. In other words, the shaft 8 has the revolv ing actions centering on the axis B-B with minute angle changes against a bearing member 22 and the member 2. As a result, a magnetic head 1 is moved toward D only with no vertical movement and with high position accuracy.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention is directed to recording still image information, etc. on a rotating magnetic sheet so as to form a plurality of concentric recording tracks, and/or recording on the recording tracks. The present invention relates to a head feeding device used in a magnetic recording and reproducing device that reproduces recorded information.

(Background of the Invention) In recent years, several compact magnetic recording devices and reproducing devices that use rotating magnetic sheets and have high recording density have been proposed and are already known.

As a head feeding device used in such a magnetic recording/reproducing device, for example, the one shown in FIG. 3 is known. In the conventional example shown in FIG. 3, the magnetic head 1 is fixed at a predetermined position on a head holding member 2, and the head holding member 2 is guided along a guide shaft 3 formed in the shape of a round bar.
The head 1 is set to be movable toward the rotation center of the magnetic sheet 4 rotated by a magnetic sheet rotation drive motor 30. On the other hand, the rotational driving force from the driving motor 5 is transmitted to the shaft 8 via driving force transmitting means (for example, gears 6 and 7 for rotation ratio conversion). This shaft 8
is rotatably supported at both ends by bearings 9 and 10, and has a male threaded portion 11. Furthermore, an engaging member 12 such as a female screw, a ball, or a needle that is screwed together with the male threaded portion 11 is provided at a corresponding position of the head holding member 2, and the male screw portion 11 and the engaging member 12 that are screwed together with each other are provided at corresponding positions on the head holding member 2. functions as a conversion means for converting rotational motion from the motor 5 into linear motion, and by moving the head holding member 2 integrally m in the direction of the arrow mark, the magnetic head 1 fixed to the head holding member 2 is magnetically moved. Move toward the center of rotation of the seat 4.

(Problems to be Solved by the Invention) However, in the conventional example shown in FIG.
If the axial centers of the second fitting portions 8b and the axial centers of the male threaded portion 11 are eccentric to each other, there is a space between the rotation center of the male threaded portion 11 and the axial center of the fiber threaded portion 11 itself. The following problems occurred because the male threaded portion 11 could rotate eccentrically due to the misalignment.

That is, due to the eccentric rotation of the fiber threaded portion 11, the engagement member 11 and the head holding member 2 are slightly displaced around the round bar-shaped guide shaft 3.

Therefore, the magnetic head 1 fixed to the head holding member 2 is similarly displaced in the vertical direction, making it difficult to maintain the position setting for contacting the magnetic head 1 with the magnetic sheet 4 with high precision (7, 7, signal There was a problem in that it affected recording and playback.

In addition, since there is usually a slight fitting gap between the guide shaft 3 and the head holding member 2, the magnetic head 1 and the head supporting it are rotated due to the eccentric state of the male threaded portion 11. The holding member 2 is also slightly displaced in the direction of arrow C parallel to the magnetic sheet 4. This displacement is caused by the magnetic head 1 during recording and reproduction on the magnetic sheet 4.
This causes a change in the azimuth angle of the magnetic sheet 4, which is undesirable for obtaining a reproduced signal with little azimuth loss.

Furthermore, when the shaft centers of the first fitting part 8a and the second fitting part 8b of the shaft 8 rotate in an eccentric state, a moment M1. M2 occurs. There is a problem in that the S vibration force generated by this moment acts in a direction that increases the rotational load on the shaft 8, thereby increasing the load on the motor 3.

Therefore, when processing the shaft 8, the "Ib"
! The alignment precision of the axial centers of the A fitting portion 8a, the second fitting portion 8b, and the male screw portion 11 is increased to minimize the eccentricity of the shaft 8, and the first ti! I! It is also possible to set the machining degree high so that the fitting gap between the fitting part 8a and the second fitting part 8b is small <K, but both of these involve an increase in the manufacturing cost of the shaft 8, and furthermore, this Therefore, it is extremely difficult to reduce the influence of the above-mentioned problems to almost zero.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and is capable of moving the head with a small driving torque at low cost, and realizing the contact relationship of the magnetic head with the magnetic sheet with high positional accuracy. An object of the present invention is to provide a highly reliable head feeding device for a magnetic recording/reproducing device.

In order to achieve this object, the present invention provides a movable structure that guides and moves a magnetic head fixed at a predetermined position of a head holding member in the direction of the rotation center of a magnetic sheet, and a magnetic head that transmits driving force to a shaft. A magnetic recording/reproducing device comprising a drive transmission mechanism that converts rotational motion of a shaft into linear motion using a threaded portion and an engagement member provided on a head holding member screwed into the threaded portion and transmits driving force to the head holding member. In the head feeding device for an apparatus, the shaft is rotatably supported only at one end remote from a position where the shaft is screwed into engagement with an engaging member provided on a head holding member.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a plan view showing one embodiment of the present invention.

First, the configuration will be described. Reference numeral 1 denotes a magnetic head, and the magnetic head 1 is fixed at a predetermined position on a head holding member 2. One end 14 of the head holding member 2 is fitted into a first guide shaft 3 in the shape of a round bar, and the head holding member 2 is guided so as to be movable in a straight line in the radial direction (in the direction indicated by the arrow) toward the rotation center of the magnetic sheet rotation drive Tanabata 30. ing. Further, on the other end side of the head holding member 2, there is a full
5 is provided, and a round bar-shaped second guide shaft 16 is fitted into @15.
The rotation of the head holding member 2 about the first guide shaft 3 is regulated by the intervention of IvJ, which regulates the vertical movement of the magnetic head 1 fixed to the head holding member 2, thereby controlling the magnetic force on the magnetic sheet 4. The height of the head 1 in the contact direction is kept almost constant. 5 is a driving pin, and the motor 5
The rotational driving force from is transmitted to the shaft 8 via the gears 6 and 7.

A male threaded portion 17 provided on the shaft 8 is screwed into a threaded engagement member 18 attached to the head holding member 2 to convert rotational motion of the shaft 8 into linear motion. shi(r
The rotation of the foot 8 causes the head holding member 2 to move in the direction D indicated by the arrow.
Drive in the direction of. The shaft 8 also has a screw engagement member 18.
An inner ring 22b of a ball bearing 22, which is a bearing member, is fitted at a fitting portion 8a at one end remote from the outer ring 22a of the bearing member 22, and an outer ring 22a of the bearing member 22 is held by a bearing holding member 9 fixed to a mounting board 31. A tension spring 21 is installed between the bottle 19 implanted at one end of the head holding member 2 and the substrate 20, and the engagement gap between the male threaded portion 17 and the screw engaging member 18 is connected to the head holding member 2. The fitting gap of the first guide shaft 3 and the fitting gap of the bearing portion consisting of the bearing member 22 in the head feeding direction (direction indicated by the arrow) are removed or biased to be minimized.

Next, FIG.
The present invention will be described in detail with reference to FIG. 2(B), which schematically shows the operation of FIG. 2(A).

Rotational driving force from motor 5 is transmitted to shaft 8 via gears 6 and 7. Here, as shown in FIG. 2(B), the rotation shaft 24 centered on the rotation center G of the bearing member 22 and the rotation shaft 23 centered on the rotation center H of the male threaded portion 17 are eccentric to each other. I will explain this assuming that there is a case.

That is, as shown in FIG. 2(A), between the fitting part 8a of the shaft 8 and the bearing member 22, or when the bearing member is composed of a ball bearing as in this embodiment, Since there is normally a small fitting gap between the outer ring 22a and the inner ring 22b, the shaft 8 can rotate by a small angle in the direction of the arrow E about the center point G. Similarly, since there is a slight engagement gap between the male threaded portion 17 and the screw engagement member 18, it is possible to rotate by a minute angle in the direction of the arrow F about the center point H.

In particular, since there are fewer screw threads in which the male threaded portion 17 and the screw engagement member 18 engage, this rotation becomes easier (for example, about one thread).

Here, when the shaft 8 is rotated by the rotational force from the motor 5 when there is a deviation of dr between the respective rotational center axes of the male threaded portion 17 of the shaft 8 and the fitting portion 8a,
Since the head holding member 2 is restricted by the guide shafts 3 and 16 so that it can move only in the direction indicated by the arrow, the axial center 23 of the threaded portion 17 and the axial center 24 of the fitting portion 8a are respectively aligned with the shift 8 With respect to B-13, which is the center axis of rotation, the robot rotates while changing the angle around 11 points and 0 point, respectively. That is, the shaft 8 performs a rotational movement about the B-[3 axis while rotating at a minute angle with respect to the bearing member 22 (in this embodiment, the outer ring 22a) and the head holding member 2. Therefore, the magnetic head 1 fixed to the head holding member 2 moves only in the direction of the arrow without vertical movement. Central axis B-13 of shaft 8
and the rotation center shaft 24 in the bearing member 22 (outer ring 22a).
The maximum possible range of the deviation angle θ with respect to θ is shown by the following equation (1).

・-1 2θ=2s+n (dr/bruise 1) -(1)(1
) As is clear from the equation ( ), the value of θ has the largest value when the magnetic head, where the distance 11,1 between point G and point H is the shortest, is at the position of the innermost recording track. However, it is usually very easy to set the value of dr/a1 sufficiently small in this type of device, for example, dr/L1 = 0.005 (T for 11-20 mm).
dr-0, 1111111), 2θ has a sufficiently small value of 0.573°.

On the other hand, the error δy in the amount of movement of the head holding member 2 in the direction of the arrow is expressed by the following equation (2).

δy≦11(1-CO82θ)...(2)(2)
As is clear from the equation, if the value of the angle 2θ can be set sufficiently small, the influence of the head feed on the positional accuracy can be almost ignored. Further, the distance between the axial centers of the tooth widths 6 and 7 changes due to the rotation of the shaft 8 with a small deviation angle with respect to the rotation center axis B-8, but the maximum value of this change δZ
The value of wax is expressed using the distance U, 2 from the center point G to one end of the gear 7, as δ7-max-2-412-sinθ-(3), and further using the deviation dr and the distance 11. , δZI
llax −2dr−Q, 2/Q, 1 − (4).

As is clear from the above equations (3) and (4), the distance 11
111! Since G,1 is sufficiently larger than the value of the deviation dr, and the distance 11 is set larger than the distance 11111 m2, the value of the displacement amount δZ max does not pose a problem. In other words, even if the shaft 8 has a misalignment d'' in its axial center, the head holding member 2 will not be displaced in any direction other than the direction indicated by the arrow, making it possible to feed the head with high positional accuracy.The present invention In the device according to the embodiment, as described above, since it is possible to turn J by a minute angle in the directions of arrows E and F at points G and H, No moment is generated around the axis of direction.

Furthermore, even if there is a deviation dr of the shaft center of the shaft 8, the rotation of the shaft 8 is set smoothly without generating any frictional force.

In the above embodiment, the cross-sectional shape of the guide shaft 3 is a round bar shape, but the cross-sectional shape of the guide shaft 3 is square, for example, to prevent the head holding member 2 from rotating around the first guide shaft 3. By configuring the guide shaft 1 as
It is also possible to omit 6.

Further, in order to set a small fitting gap between the groove 15 of the head holding member 2 and the guide shaft 16, a plate spring is provided on the head holding member 2, and the plate spring and a part of the groove 15 are connected to the second guide shaft 16. It may be configured to sandwich the .

Further, although a ball bearing 22 is incorporated as a bearing member to pivotally support the shirt 18, the structure is not limited to ball bearings, and any suitable bearing member may be used.

(Effects of the Invention) As described above, according to the present invention, in a head feeding device of a magnetic recording/reproducing device using a rotating magnetic sheet, in which the rotation of a feed screw member is used for track switching of a magnetic head, a feed screw member is provided. It is possible to minimize the positioning error of the magnetic head due to the deviation of the axial center of the member, and it is also possible to almost eliminate the frictional force generated due to the deviation of the axial center during rotation of the feed screw member. Therefore, it is possible to achieve highly accurate positioning of the magnetic head without requiring high accuracy in shaft machining of the feed screw member, and the motor that is the driving force source for the feed screw member can also be a motor with a small output. Since you can use
Not only can the manufacturing cost of the head feeding device be lowered, but
The overall magnetic recording/reproducing device can be miniaturized and can be incorporated into devices such as electronic still cameras that require compact, high-density recording.

[Brief explanation of drawings]

FIG. 1 is a plan view showing one embodiment of the present invention, and FIG. 2 (A
) is a sectional view taken along line A-A in Figure 1, and Figure 2 (B) is a cross-sectional view taken along line A-A in Figure 1.
FIG. 3 is a plan view showing a conventional example. 1: Magnetic head 2: Head holding member 3.16: Guide shaft 4: Magnetic sheet 5: Motor 6.7: Gear 8: Shaft 9.10: Bearing 11.12.17.18: Threaded part 14.15: Groove 19: Bin 20: Substrate 21: Tension spring 22: Ball bearing

Claims (1)

[Claims] Recording is performed by moving a magnetic head in the radial direction of a rotating magnetic sheet to form a plurality of concentric recording tracks, and/or recording signals are reproduced from the rotating magnetic sheet recorded as described above. A magnetic recording/reproducing device comprising: a magnetic head holding member that holds the magnetic head in a predetermined position; a guide member that regulates the moving direction of the magnetic head holding member in the radial direction; and a feeder that is threadedly engaged with the magnetic head holding member. a screw member, a rotational drive means for rotationally driving the feed screw member, and a feed screw fitted to the feed screw member such that the magnetic head holding member can be moved in the radial direction by rotation of the feed screw member. a bearing member that rotatably supports the member, and the bearing member is configured such that when the feed screw member rotates, the feed screw member allows slight movement in a direction other than the direction parallel to the axial direction of the feed screw member. A head feeding device for a magnetic recording/reproducing device, characterized in that it is configured to support a feed screw member.