JPS6213727B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating magnetic head device, and particularly to a device in which a rotating magnetic head support supporting a magnetic head at both ends is swingably (see-saw) provided in a drum. It is an object of the present invention to provide a rotating magnetic head device which is capable of stably holding a magnetic head support in an equilibrium state, and which allows swinging motion of the support by electromagnetic driving means with low power consumption.

Currently, as one type of rotating magnetic head device equipped with a so-called automatic tracking function, a rotating magnetic head support having magnetic heads at both diametrically upper ends is installed in the drum so that it can see-saw, and a control signal is supplied to the drum. There is a rotary magnetic head device in which the support body is oscillated by an electromagnetic driving means that is activated by the rotation of the magnetic head. In this device, in order to form a video track with good linearity, the device must be kept stable in a plane perpendicular to the rotation axis during recording (playback), and when swinging, it must be kept stable in a plane perpendicular to the rotation axis. In order to reduce the power consumption of the drive means, it is necessary to swing with a small force.

Here, a spring member is generally used as a mechanism to swingably support the magnetic head support, but using a member with a large spring constant is convenient for the above-mentioned reasons, but it is This results in the disadvantage that the required force is large, power consumption increases, and tracking accuracy is adversely affected in some cases. Conversely, using a spring member with a small spring constant is advantageous in the above points, but
This causes a disadvantage that the track pattern may be bent.

The present invention satisfies both of the above conditions, and one embodiment thereof will be described below with reference to the drawings.

FIG. 1 is a plan view showing an embodiment of a rotating magnetic head device according to the present invention, with the upper rotating drum omitted;
Figures 2 and 3 are the - lines and - lines in Figure 1, respectively.
4 is a perspective view showing the upper rotating drum assembly in FIGS. 1 to 3 upside down, and FIG. 5 is an exploded perspective view of the upper rotating drum assembly in FIG. 4. It is.

In each figure, a rotating magnetic head device 1 consists of a lower stationary drum 2 and an upper rotating drum assembly 3, around which a magnetic tape 4 runs. The rotating shaft 5 is rotatably supported by bearings 6a and 6b, and a base plate 7 is fitted and fixed thereto. As shown in FIGS. 4 and 5, the rotating drum assembly 3 includes a rotating drum main body 8, a rotating yoke 9, and a leaf spring member 10, and the rotating drum main body 8 is fitted to the rotating shaft 5. It is screwed to the base plate 7. The rotating transformer 11 is
It consists of a fixed winding mounting part 12 fixed to the fixed drum 2 and a rotating winding mounting part 13 fixed to the base plate 7 and rotating integrally therewith.

The rotating yoke 9 is supported on the lower surface side of the rotating drum main body 8 by a leaf spring member 10, with a center hole 9a loosely fitted onto the rotating shaft 5. As a result, the rotating yoke 9 rotates integrally with the rotating drum main body 8, and oscillates about an axis orthogonal to the rotating shaft 5 with elastic deformation of the leaf spring member 10 due to the action of the electric drive mechanism 17, which will be described later. Do a see-saw movement.

Further, the rotating yoke 9 has yoke portions 9b and 9c formed at both upper end sides in the diametrical direction.
Permanent magnet pieces 14a and 14b are fixed inside b and 9c. Further, the magnetic heads 15a, 15b are fixed to brackets 16a, 16b, respectively, and each bracket is attached to each yoke portion 9b, 16b of the rotating yoke 9, respectively.
It is fixed to the top side of 9c with screws.

The electromagnetic drive mechanism 17 includes the yoke portions 9b and 9c.
The drive coil 1 is placed in a magnetic field of opposite polarity formed within the drive coil 1.
8 is inserted into the structure. Drive coil 18
is the coil winding frame 19 fixed to the fixed drum 2.
It is wrapped around.

Next, the structure and operation of the rotating yoke support section, which constitutes the main part of the present invention, will be explained with particular reference to FIGS. 4 and 5.

The rotating yoke 9 has arm portions 9d and 9e, and the lower surface side of the central portion (the attachment portion of the leaf spring member 10) is a concave surface portion 9f.

An arc-shaped stepped protrusion 8 is provided on the lower surface side of the rotating drum 8.
a and 8b are formed, and the inner parts thereof are stepped surfaces (receiving surfaces) 8 _a-1 and 8 _b-1 .

The leaf spring member 10 includes an inner circumferential annular portion 10a, an outer circumferential annular portion 10b, and a connecting arm portion 1 that connects both annular portions.
It is a flat member consisting of 0c and 10d. Both the annular parts 10a and 10b are arranged concentrically, and the connecting arms 10c and 10d are aligned on one diameter. Attachment holes 10e, 10f, 10g are provided at both ends of the connecting portions 10c, 10d in each of the annular portions 10a, 10b.
10h is formed.

As shown in FIGS. 6 and 7, the leaf spring member 10 has screws 20a and 20b inserted into the holes 10.
f, screw hole 9g of rotating yoke 9 through 10g,
9h, and the screws 21a and 21b are connected to the hole 10.
e and 10h, and are screwed into the screw holes 8 _a-2 and 8 _b-2 of the circular stepped protrusions 8 a and 8 b. That is, the rotating yoke 9 has the connecting arms 10c,
10d is positioned in a plane orthogonal to the rotating shaft 5, and is supported by the connecting arms 10c and 10d so as to be able to swing with this torsional deformation. Further, the leaf spring member 10 is in a state in which the inner circumferential annular portion 10a is in contact with the concave surface portion 9f of the rotating yoke 9, that is, each arcuate portion 1 of the outer circumferential annular portion 10b
0 _b-1 and 10 _b-2 are screws 21 as shown in Figure 7.
The attachment portions a and 21b are forcibly elastically deformed downward and are in pressure contact with the arm portions 9d and 9e.

Therefore, when the electromagnetic drive mechanism 17 is in a non-operating state, the rotating yoke 9 rotates each arm 9d, 9e.
The plate spring member 10 is in an equilibrium state in which the elastic forces stored in the arcuate portions 10 _b-1 and 10 _b-2 act on the plate spring member 10 (see FIGS. 9A and 9B). Here, if the spring constants of the circular arc portions 10 _b-1 and 10 _b-2 of the leaf spring member 10 are respectively k, then the rotating yoke 9 has a spring constant (k
An equilibrium state is reached with the spring +k) acting. Note that the torsion spring force of the connecting arms 10c and 10d also acts on the rotating yoke 9, and this torsional spring force also acts in the same way when the rotating yoke 9 performs a swinging operation as described later. In the following explanation, for convenience of explanation, the action of the torsion spring force of the connecting arms 10c and 10d will be ignored.

When the electromagnetic drive mechanism 17 is activated by the input control current, the rotating yoke ₁₁ swings as shown in FIGS.
The elastic forces acting on the arms 9d and 9e of the rotating yoke 9 of 0 _b-2 change as shown in FIGS. 9A and 9B.
Here, the clockwise rotation of the rotary yoke 9 is positive, the counterclockwise rotation is negative, and the circular arc portion 10 _b of the leaf spring member 10 is
The direction of the elastic force of ₁ is positive, and another circular arc part 10 _b-2
The direction of the repulsive force is negative.

When the rotating yoke 9 rotates clockwise from the above equilibrium state (Fig. 8A), the arc portion 10 _b-1 further deforms in the direction of elastic deformation, and the arc portion 10 _b-2 deforms in the direction of return. do. The elastic force of the circular arc portion 10 _b-1 increases linearly as shown by graph line _-1 in FIG. 9A. Looking at another circular arc portion 10b _-2 , when the rotary yoke 9 is tilted at a predetermined angle α (corresponding to the displacement δ of the magnetic head), it is received by the stepped surfaces 8a _-1 and 8b _-1 , Thereafter, it moves away from the yoke arm 9e, and the repulsive force of the circular arc portion 10b _-2 with respect to the yoke arm 9e changes as shown by graph line _-1 in FIG. 9B.

When the rotating yoke 9 rotates counterclockwise from the above-mentioned equilibrium state (Fig. 8B), the arcuate portion 10 _b-2 deforms further in the direction of elastic deformation, contrary to the above case, and this elasticity deforms. The repulsive force increases linearly as shown by graph line _-2 in FIG. 9B. Arc part 10 _b- on the opposite side
₁ , the rotating yoke 9 is rotated at a predetermined angle −α
When it is tilted (corresponding to the displacement -δ of the magnetic head), it is caught by the stepped surfaces 8 _a-1 and 8 _b-1 ,
After that, move away from the yoke arm portion 9d and move away from this arcuate portion 10.
The elastic force of _b-1 against the yoke arm 9d is shown in Figure 9A.
Changes as shown by middle graph line _-2 .

Here, the plate spring member 10 when the rotating yoke swings.
The yoke arm portions 9d of the arc portions 10 _b-1 and 10 _b-2 ,
The total elastic force acting on 9e is as shown by the nonlinear graph line in FIG. In other words, the graph line has a steeper slope between the angles α and -α than other parts.

Furthermore, when the rotating yoke 9 is further swung from a certain oscillating position, the force that causes it to return to its original oscillating position is as follows:
It is expressed as a graph line obtained by differentiating the graph line in FIG. That is, the restoring force between angles α and −α is twice the restoring force at other angular positions.

Here, the following can be understood from the graph lines in FIGS. 9A and B and FIG. 10.

When the rotating yoke 9 is in the swinging position of angle α to −α, both arcuate portions 10 _b-1 and 10 _b-2 are acting, and in this range the spring constant is (k+
k)=2k, and as shown by the graph line in FIG. 10, twice the restoring force is applied compared to the swing position outside the above angle range. Therefore, when the electromagnetic drive mechanism 17 is inactive, the rotating yoke 9 is stably held at the equilibrium position shown in FIG. The magnetic heads 15a and 15b rotate in a plane of rotation perpendicular to the rotation axis 5, and the magnetic heads 15a and 15b form tracks with excellent linearity on the magnetic tape.

When the rotating yoke 9 swings beyond the above angle range, only one circular arc portion acts, and the elastic force acting on the rotating yoke 9 is approximately 1/2 of that when both circular arc portions act. . That is, the resistance to the swinging of the rotating yoke 9 is small, and therefore the force generated by the electromagnetic drive mechanism 17 is also small. Therefore, the electromagnetic drive mechanism 17 can be made compact, and the current consumption of the electromagnetic drive mechanism 17 can be reduced. Therefore, the swinging control of the rotating yoke can be performed with high accuracy.

Note that the above-mentioned swing angles α and −α are the rotational yoke 9
It is determined by the dimension X between the arm parts 9d, 9e and the stepped surfaces 8a _-1 , _8b-1 of the circular stepped protrusions 8a, 8b (which generally corresponds to the step dimension of the concave surface part 9f). , which is actually an extremely small value.

Therefore, during recording and normal reproduction, the rotating magnetic head device 1 operates with the electromagnetic drive mechanism 17 inactive, and the rotating yoke 9 is operated by the action of the arcuate portions 10 _b-1 and 10 _b-2. The magnetic head 15 rotates while being stably held in the equilibrium position shown in FIG.
a and 15b scan the magnetic tape 4 with good linearity.

Further, in the case of special playback such as still image playback, slow playback, or double speed playback, the electromagnetic drive mechanism 17 is operated by a control signal to swing the rotary yoke 9 beyond the angle α to -α. The rotating yoke 9 is swung with a relatively small force. As a result, the magnetic heads 15a and 15b scan the video track, and special reproduction is performed satisfactorily.

FIGS. 11 to 13 show other embodiments of the rotary yoke support portion, which is an essential part of the present invention. In each figure, the same components as those shown in FIGS. 1 to 8 are denoted by the same reference numerals, and the explanation thereof will be omitted.

The rotating yoke support portion in FIG.
A is formed as a flat surface without forming the concave surface portion 9f, and the plate spring member 10 is formed with each arcuate portion 10 _b-1 , 1
0 _b-2 through spacers 25a and 25b, the arcuate portions 10 _b-1 and 10 _b-2 are forcibly curved and attached to the spacer 25a and 25b.

The leaf spring member 10A in FIG.
U-shaped bent portions 10 _b- 3 and 10 _b-4 are formed in each of the circular arc portions 10 _b-1 and 10 _b-2 of 0b. 13th
The plate spring member 10B in the figure has each arc portion 10 _b-1 , 1
Embossed portions 10 _b-5 and 10 _b-6 are formed on 0 _b-2 .

The plate spring members 10A and 10B are provided with 10 b-3 and 10 _b-3 at the bent portions of the flat arm portion of the rotating yoke 9A shown in FIG.
10 _b-4 or embossed portions 10 _b-5 and 10 _b-6 are pressed against each other, and the arc portions 10 _b-1 and 10 _b-2 are mounted in a curved state.

FIG. 11 to FIG. 13 Middle plate spring members 10, 10
The restoring action of A and 10B on the rotating yoke 9 is as follows:
This is the same as in the previous embodiment, and the explanation thereof will be omitted.

In addition, as the leaf spring members 10, 10A, 10B, arcuate portions 10 _b-1 , 10 _b-2 of the outer circumferential annular portion 10B are used.
It is also possible to configure the arc part 10 b-1 or 1 separately from other parts, and furthermore, when the rotating yoke swings, the arc part 10 _b-1 or 1
Instead of the stepped surfaces 8 _a-1 and 8 _b-1 , a circular arc portion 10 is screwed onto the rotating drum main body 8 as a member that serves to interrupt the action of the yoke arm of 0 _b- 2.
Appropriate adjustment screws to accommodate _b-1 and 10 _b-2 can also be applied.

Further, in the above embodiment, the leaf spring member 10
(10A, 10B) are their arc parts 10 _b-1 , 10 _b-2
is installed in a forcibly curved state in advance, and the circular arc portion follows the swinging movement of the rotating yoke up to a certain angle range by elastic recovery of the circular arc portion.

Furthermore, although the drum in the above embodiment has a structure consisting of a lower fixed drum and an upper rotating drum, the rotating magnetic head device of the present invention is not limited to this drum structure; for example, the upper and lower drums It can also be applied to a guide drum having a double structure in which a drum is fixed and a rotating drum is arranged between them.

As described above, the rotating magnetic head device according to the present invention includes a magnetic head support having magnetic heads at both ends thereof, which is rotatable within a drum and swingable by an electromagnetic drive means operated by the supply of a control signal. In the apparatus, left and right elastic members are provided that act on the left side and the right side with respect to the swing center of the magnetic head support, and when the magnetic head support swings by a predetermined angle or more, one of the elastic members By having a configuration in which the action on the magnetic head support is blocked, it is possible to stably hold the magnetic head support in an equilibrium position with both elastic members acting on it, and therefore it is possible to use a special magnetic head support fixing method. It is possible to form a track with good linearity without applying any conversion means, and furthermore, the resistance to the swinging of the magnetic head support during special playback is relatively small, and therefore the The electromagnetic drive mechanism can be constructed in a compact size, its power consumption can be reduced, and rocking motion can be performed accurately.Furthermore, by using leaf spring members that have been elastically deformed in advance as the left and right elastic members, magnetic The configuration is such that the leaf spring member, which elastically returns to its original position in response to the swinging of the head support, is received in the direction of displacement and blocks the action of the leaf spring member on the magnetic head support, which simplifies the configuration. Further, by integrally forming the leaf spring member with the spring portion that swingably supports the magnetic head support, the spring mechanism can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of a rotating magnetic head device according to the present invention, with the upper rotating drum omitted;
Figures 2 and 3 are the - lines and - lines in Figure 1, respectively.
4 is a perspective view showing the upper rotating drum assembly in FIGS. 1 to 3 upside down, and FIG. 5 is an exploded perspective view of the upper rotating drum assembly in FIG. 4. , FIG. 6 is a plan view of the rotating yoke support part in FIGS. 4 and 5, FIG. 7 is a side view of the rotating yoke support part when the rotating yoke is in an initial equilibrium state, and FIGS. B is a diagram showing the state of the rotary yoke support part when the rotary yoke swings, and FIG. 9A
and B are diagrams showing the state in which each circular arc portion of the leaf spring member is biased with elastic force against the rotary yoke as the rotary yoke swings, and FIG. 10 shows the leaf spring member when the rotary yoke is rocking. 11 is a diagram showing the resiliency applied to the rotating yoke due to the action of both arcuate portions of the rotating yoke, and the changing state of the restoring force of the rotating yoke. FIG. FIG. 12 is a perspective view showing another embodiment of the leaf spring member that can be applied to the rotating yoke support portion, and FIGS. 13A and 13B are each a further embodiment of the leaf spring member. FIG. 3 is a perspective view and a side view of an example. DESCRIPTION OF SYMBOLS 1...Rotating magnetic head device, 2...Lower fixed drum, 3...Upper rotating drum assembly, 4...
Magnetic tape, 5... Rotating shaft, 7... Base plate, 8... Rotating drum body, 8 _a-1 , 8 _b-1 ... Stepped surface (receiving surface), 9, 9A... Rotating yoke,
9b, 9c...Yoke part, 9d, 9e...Arm part,
9f... Concave surface portion, 10, 10A, 10B... Leaf spring member, 10a... Inner circumferential annular portion, 10b... Outer circumferential annular portion, 10 _b-1 , 10 _b-2 ... Arc portion, 10 _{b -
3} , 10 _b-4 ... bending part, 10 _b-5 , 10 _b-6 ... embossed part, 15a, 15b ... magnetic head, 17
...Electromagnetic drive mechanism, 18...Drive coil, 19...
...Coil winding frame, 25a, 25b...Spacer.

Claims (1)

[Scope of Claims] 1. Magnetic head supports, each having magnetic heads mounted at positions 180 degrees symmetrical with respect to the center of rotation, are coupled to the rotating drum so that they can rotate integrally with the rotating drum. In addition, by means of a swinging support provided near the perpendicular bisector of the straight line connecting the magnetic heads, during rotation, the plane containing each magnetic head and the plane orthogonal to the extension direction of the rotation axis are formed. The magnetic head support is swingably supported so that its angle can be changed, and when a driving force is applied to the magnetic head support by an electromagnetic drive mechanism operated by a control signal, the magnetic head support In a rotating magnetic head device in which a magnetic head rotates integrally with a rotating drum and is capable of swinging around its swinging support, the rotation center of the magnetic head support is left and right elastic members that respectively act on the left and right portions to bring the magnetic head support into an equilibrium position; A rotating magnetic head device comprising means for blocking the action of one of the elastic members on the magnetic head support. 2. The left and right elastic members are left and right leaf spring members that have been elastically deformed in advance, and the blocking means is configured to operate the left and right leaf spring members within the drum according to the swinging direction of the magnetic head support. Claim 1, characterized in that it is a leaf spring member receiving portion that receives one of the leaf spring members in the direction of displacement of the leaf spring member and blocks the action of the leaf spring member on the magnetic head support. Rotating magnetic head device as described in . 3. The rotating magnetic head device according to claim 2, wherein the left and right leaf spring members are integrally formed with a spring portion that swingably supports the magnetic head support.