JPH04219616A - Magnetic head rocking device - Google Patents

Abstract

PURPOSE:To suppress the shifting angle of a magnetic head generated attending on the rocking of the magnetic head in a magnetic head rocking device used at the magnetic recording and reproducing device and to offer a small-sized and a thin-shaped the magnetic head rocking device having an excellent characteristic. CONSTITUTION:First and second magnetic heads 1, 2 are adhered to a magnetic head predestal 3 and a bimorph element 7 is divided with two grooves 12, 13 and bimorph beams 20, 22 at both sides and a bimorph beam 21 being shorter in the central part than them are formed and then the magnetic head predestal 3 and the bimorph beams 20, 21, 22 are connected with elastic connecting members 4, 5, 6. An electrode 11 formed on the bimorph element 7 is longer in the central part, so the amplitudes of the bimorph beams 20, 21, 22 are approximately the same and the magnetic head predestal 3 is moved nearly in parallel.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head swinging device for swinging a magnetic head of a magnetic recording/reproducing device.

0002

[Prior Art] In recent years, recording and reproducing devices using magnetic recording have been widely used in VTRs, etc., and due to the trend of increasing signal volume due to digitization, head drum devices are rotating more than three times as much as conventional ones. Faster rotation speeds, shorter wavelength recording, narrower tracks, and weaker magnetic tapes are becoming thinner. Under such circumstances, a mechanical issue requires a good head touch in which the magnetic head can correctly trace the recorded track and efficiently extract short-wavelength recording signals.

Conventionally, this type of device has had the following structure. FIG. 15 is a schematic perspective view showing a first conventional example of a head swinging device. In FIG. 15, 1 is a first magnetic head, 2 is a second magnetic head, and 35 is a first magnetic head.
A magnetic head base 8 is used to glue and fix the magnetic head 1 and the second magnetic head 2, and 8 is a fixing base on which the swinging means 36 made of bimorph is sandwiched between a presser holder 9 and a screw 10 and fixed in a cantilever shape. , 14 connects the fixing base 8 to the main body (not shown)
This is a fixing screw hole for fixing to.

The operating principle of the swinging means 36 made of bimorph is well known, and as shown in FIG.
Thin film electrodes 11, 17, 18,
19 are formed and laminated, and when a voltage is applied to opposite electrodes of each piezoelectric element 16, 19 with a common central electrode, the swinging means 36 bends due to the expansion and contraction of the piezoelectric elements 16, 19. Taking these into consideration, Figure 15
The operation will be explained using a schematic side view of the bimorph 36 in the applied state in FIG. 17.

In FIG. 15, when a voltage is applied to a bimorph 36 serving as a swinging means, the bimorph 36 curves into an arc shape and lifts the first and second magnetic heads 1 and 2. At this time, the contact position of the magnetic tape 52 running along the drum outer periphery 48 moves from the horizontal position. Since the first and second magnetic heads 1 and 2 extend in the tangential direction of the tip of the swinging means 36, an angle, that is, a tilt angle occurs in the contact with the magnetic tape 52.

FIG. 18 is a schematic perspective view showing a second conventional example disclosed in Japanese Patent Application Laid-Open No. 53-36209. Figure 18
, 38 and 39 are rocking means 3 made of bimorphs.
First and second electrodes 40 and 41 separated in the longitudinal and lateral direction on the front and back sides of 6 are jumper wires that apply a reverse voltage to the first and second front and back electrodes. In this configuration,
The central electrode is grounded, and forward and reverse voltages are applied to the front and back sides of the element. FIG. 19 is a side view of the state in which this voltage is applied. At the first electrode 38 part, the first and second magnetic heads 1
, 2, while the second electrode 39 acts in a direction to lower the first and second magnetic heads 1, 2, and the contact angle with the magnetic tape 52 is compared to that of the first embodiment. and become more relaxed.

FIG. 20 is a schematic perspective view showing a third conventional example having two swinging means disclosed in Japanese Patent Laid-Open No. 55-92088. In FIG. 20, 42 is a magnetic head base having a thin elastic member adhered to two bimorph elements 43 and 44 arranged in parallel, and 45 is a spacer for arranging the bimorph elements in parallel.

The operation of the third conventional example will be explained using FIG. 21. When a voltage is applied to the two bimorph elements 43 and 44, the bimorph elements 43 and 44 deform into an arc shape as shown in FIG. The magnetic head base 42 and bimorph elements 43 and 44 are connected by elastic members 45 and 46,
The bending of the bimorph elements 43, 44 that have moved in parallel is absorbed by the elastic members 46, 45, and the magnetic head 1,
2 in parallel.

[0009]

[Problems to be Solved by the Invention] However, in the above conventional configuration, although the first conventional example can be configured with one bimorph element, when the amplitude is increased, there is an angular deviation between the magnetic head and the magnetic tape. occurs, the contact between the magnetic tape and the magnetic head becomes poor, and the signal cannot be sufficiently extracted.Also, in the second conventional example, the tip of the bimorph returns the swing angle, which improves the contact. Furthermore, in the third conventional example, it is necessary to stack two bimorph elements at a distance, which requires space and makes it difficult to make the device smaller and thinner. Ta.

The present invention solves the above-mentioned various conventional problems, and is capable of reducing the size and thickness of a magnetic recording and reproducing device, which has a small swing angle due to the amplitude of the magnetic tape and the magnetic head, and has a good head touch. The purpose is to provide equipment.

[0011]

Means for Solving the Problems In order to achieve this object, a magnetic head swinging device of the present invention has a magnetic head base for holding a magnetic head, a plurality of beams, and the magnetic head base and A rocking means for rocking the magnetic head base in the width direction of the magnetic head via a plurality of connecting means elastically coupled to the plurality of beams, and a fixing device in which the rocking means has a cantilever shape. and means for making the height of at least one beam of the swinging means in the swinging direction different from the height of the other beams in the swinging direction at a position where the distance from the fixing means is the same. . Furthermore, at least one of the plurality of connecting means does not overlap in the longitudinal direction of the side beam.

0012

[Operation] With the above-described structure, the present invention changes the height of the tip of a plurality of beams in the swinging direction of at least one beam of the swinging means during swinging, and the height of the other beams in the swinging direction. The tilting angle of the magnetic head bases connected via the connecting member is controlled by the change.

[0013]

[Embodiment] An embodiment of the present invention will be explained based on the drawings.

FIG. 1 is a perspective view showing a first embodiment of the present invention. In FIG. 1, 1 is a first magnetic head, 2 is a second magnetic head, 3 is a magnetic head base for adhesively fixing the first and second magnetic heads 1 and 2, and 7 is a bimorph serving as a swinging means. 11 are electrodes formed on the front, center, and back surfaces of the bimorph element 7, 12 and 13 are two grooves formed in the longitudinal direction of the bimorph element 7, and 20, 21, and 22 are the grooves 1.
Bimorph beam divided by 2 and 13 into multiple beams,
4, 6, and 5 are bonded connecting members that elastically connect the tips of the bimorph beams 20, 21, and 22 to the magnetic head base 3; 8, the bimorph element 7 is cantilevered by a holding plate 9 and a set screw 10; The fixing base 14 is a hole for fixing the fixing base 8 to the main body with screws.

In FIG. 1, the electrode 11 formed on the bimorph element 7 spreads from the holding plate 9 side and is long on the central bimorph beam 21, and short on the left and right bimorph beams 20, 22. Furthermore, the left and right bimorph beams 20, 22
is longer than the central bimorph beam 21, while the center of the magnetic head base 3 protrudes and the left and right sides are recessed.

FIG. 2 is a schematic perspective view of the magnetic head swinging device attached to a rotating drum. 47 is a rotating drum, 48 is a magnetic tape running surface of the rotating drum 47, 50
49 is a fixing screw for fixing the magnetic head swinging device to the rotating drum 47; 51 is a first hole drilled on the magnetic tape running surface 48 of the rotating drum 47;
This is a window for protruding the second magnetic heads 1 and 2. In the head drum device configured in this manner, the first and second magnetic heads 1 and 2 are oscillated in a direction substantially perpendicular to the mounting surface of the magnetic head oscillation device.

The operation of the first embodiment of the present invention is shown in FIGS. 1 and 3.
, 4 and 5. FIG. 3 is a side steady-state diagram of FIG. 1. In a steady state where no voltage is applied to the bimorph element 7, the bimorph element 7 extends horizontally, and the first and second magnetic heads 1 and 2 move toward the magnetic tape running surface 4.
The magnetic tape 52 running along the magnetic tape 8 is substantially perpendicular to the magnetic tape 52 . When a voltage is applied to the bimorph element 7, a characteristic of the bimorph element 7 is that it deforms into an arc shape. FIG. 4 shows the state in which it is deformed upward. The bimorph element 7 and the bimorph beam 21 on which the electrode 11 is formed are deformed into an arc shape, but the bimorph beams 20 and 22, which have a portion where the electrode 11 is not formed, have a straight portion touching the portion deformed into an arc shape. It is extending. For this purpose, the bimorph beam 21
and the bimorph beams 20 and 22 generate a relative height difference in the height direction of the bending direction. By selecting these lengths, the amplitudes near the bonding portion of the connecting member 6 of the bimorph beam 21 and near the bonding surfaces of the connecting members 4 and 5 of the bimorph beams 20 and 22 can be set to be approximately the same. On the other hand, there are length differences in the longitudinal direction of the bimorph beams, and one horizontal plane having three points at their tips can be configured. On the other hand, since the magnetic head base 3 is connected by connecting members 4, 5, 6 having the same length (distance) and having a substantially uniform spring constant at the flattened portion, these connecting members 4, 5, 6 As a result, the magnetic head base 3 moves in the horizontal direction.

FIG. 5 is a schematic side view of the bimorph when it is deformed in the opposite direction to that shown in FIG. Similarly to FIG. 4, a height difference occurs between the bimorph beams 20, 22 and the bimorph beam 21 in the deflection direction, and the heights are approximately the same at the tips, and the magnetic head base 3 moves approximately in parallel. .

In order to reduce deformation in the width direction, the length difference between the left and right bimorph beams 20, 22 and the center bimorph beam 21 is made equal, and the lengths of the bridge portions of the connecting members 4, 5, 6 are made equal. ing. In addition, in order to prevent twisting in the bending direction, the left and right grooves 12 and 13 are made symmetrical, and the left and right grooves 12 and 13 are bent in the same manner to eliminate the influence of the relative height deviation between the bimorph beams 20 and 22 and the bimorph beam 21. It extends to the electrode part. On the other hand, the reason why the left and right bimorph beams 20 and 22 are longer is to support the magnetic head base 3 as close as possible to the first and second magnetic heads 1 and 2 and to increase torsional rigidity.

FIG. 6 is a schematic perspective view showing a second embodiment of the present invention. In FIG. 6, 53 and 54 are electrodes formed on the left and right bimorph beams 20 and 22, and 55 is an electrode formed on the center bimorph beam 21.
It is configured on the center and back sides, and the electrodes are connected on each layer.

As shown in FIG. 6, the relative positions in the longitudinal direction of the bimorph element 7 of the electrodes 53, 54 and the electrode 55, which have approximately equal lengths in the longitudinal direction of the bimorph element 7, are the same as those of the bimorph beams 20, 22 and the bimorph beam 21. It is shifted by the length of . On the other hand, as in the first embodiment, the spring constants of the bimorph beam 21 and the bimorph beams 20, 22 and the connecting member 4,
The length, thickness, and width of the connecting member 5 and the connecting member 6 are approximately the same so that their spring constants are approximately the same. When a voltage is applied to such a magnetic head rocking device, it is normally horizontal, but as shown in FIG.
0 and 22 are deformed into an arc shape, but at this time, since the bimorph beam 21 constitutes the electrode 55 from the vicinity of the holding plate, it deforms into an arc shape from the root, but the bimorph beams 20 and 22 are deformed into an arc shape from the base. Since the positions of the electrodes 53 and 54 are separated from the holding plate by the length, this part remains horizontal, and the part where the electrodes 53 and 54 are formed is moved horizontally in parallel to the bimorph beam 21. make the same transformation. As a result, the bimorph beam 21 and the bimorph beam 20
, 22 have the same tilt angle and the same height in the vicinity of the bonding position of the connecting members. The connecting members 4, 5, and 6 undergo substantially the same deformation, and the magnetic head base 3 moves in parallel.

FIG. 8 shows a state in which the bimorph element 7 is swung in the opposite direction to that shown in FIG. 7, but the deformation is similar to that shown in FIG. 7, and the magnetic head base 3 is also moving in parallel.

FIG. 9 is a perspective view showing a third embodiment of the present invention, which differs from the first embodiment shown in FIG. 1 in that the left and right bimorph beams 25 and 26 and the center bimorph beam 27 are separate. It is made up of the body. Similar to the first embodiment,
The left and right bimorph beams 25, 26 are long, and the electrodes 28,
30 is shorter than electrode 29. Since the electrodes 28, 29, and 30 are constructed as separate bodies, the wire rod 23,
Connected by 24. Since the end face of the groove is a separate member, stress concentration can be prevented. The operation is the same as in the first embodiment.

FIG. 10 is a perspective view showing a fourth embodiment of the present invention. In FIG. 10, 31 and 32 are left and right bimorph beams, 27 is a center bimorph beam, and 33 and 34 are electrodes provided on the front, center, and back surfaces of the left and right bimorph beams 31 and 32, respectively.

In FIG. 10, left and right bimorphs 31,
32 and the central bimorph beam 27 are made of different materials and have different lengths, and the short central bimorph beam 27 is configured to be deformed to a large extent. Left and right bimorph beams 31, 32
are made of the same material and have the same shape. The bimorph beam 27 and the bimorph beams 31 and 32 are deformed in different arcs because the elongation of the bimorphs with respect to the voltage is different. However, as shown in the first embodiment, the heights of the bimorph beam 27 and the bimorph beams 31, 32 can be made substantially the same in the vicinity of the bonding positions of the connecting members 4, 5, and 6. Therefore, in order to uniformly deform the connecting members 4, 5, and 6, the magnetic head base 3 can be moved approximately in parallel, and the first and second
The magnetic heads 1, 2 and the magnetic tape 52 can be brought into contact without changing the tilt angle. This state is shown in FIG. 11 in an upwardly swung state and in FIG. 12 in a downwardly swung state. It is moving almost parallel.

In FIG. 1, the connecting members 4 and 5 bonded to the left and right bimorph beams 20 and 22 are placed at the same distance from the fixed base 8, and the elastic connecting members 4 and 5 are shown in FIG. They overlap in the side view. However, the connecting member 6 bonded to the central bimorph beam 21 is installed on the fixed base 8 side. At this time, bimorph beam 2
0 and 22 and the magnetic head base 3 overlap on the sides. If this overlap does not exist, the section modulus of only the connecting members 4, 5, and 6 will be very small, and this row will bend or break when subjected to force P, as shown in FIG. In order to prevent this, as shown in the side view of FIG.
22 to share the force and increase the strength.

[0027]

As described above, the present invention has a magnetic head base for holding a magnetic head, a plurality of beams, and a plurality of connecting means for elastically coupling the magnetic head base and the plurality of beams. a swinging means for swinging the magnetic head base in the width direction of the magnetic head via the swinging means; a fixing means for making the swinging means into a cantilever shape;
and means for varying the height of at least one of the plurality of beams in the swinging direction at positions at equal distances from the fixing means, the magnetic head can be moved horizontally in a planar configuration; It is possible to construct a magnetic head rocking device that is small and thin and has a sufficient amount of deflection.
Its practical effects are enormous.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing a magnetic head swinging device in a first embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a state of attachment to a head drum in the first embodiment.

FIG. 3 is a schematic side view showing the no-load state of the first embodiment.

FIG. 4 is a schematic side view of the first embodiment when a bimorph voltage is applied.

FIG. 5 is a schematic side view of the first embodiment when a bimorph voltage is applied.

FIG. 6 is a schematic perspective view showing a magnetic head swinging device in a second embodiment of the present invention.

FIG. 7 is a schematic side view for explaining the operation of the second embodiment.

FIG. 8 is a schematic side view for explaining the operation of the second embodiment.

FIG. 9 is a schematic perspective view showing a magnetic head swinging device according to a third embodiment of the present invention.

FIG. 10 is a schematic perspective view showing a magnetic head swinging device in a fourth embodiment of the present invention.

FIG. 11 is a schematic side view for explaining the operation of the fourth embodiment.

FIG. 12 is a schematic side view for explaining the operation of the fourth embodiment.

13 is a side view for explaining the operation of the first embodiment shown in FIG. 1. FIG.

14 is a schematic side view for explaining the operation of the first embodiment shown in FIG. 1. FIG.

FIG. 15 is a schematic perspective view showing a magnetic head swinging device in a first conventional example.

FIG. 16 is a schematic side view for explaining the operation of the bimorph element.

FIG. 17 is a side view for explaining the operation of the first conventional example.

FIG. 18 is a schematic perspective view showing a magnetic head swinging device in a second conventional example.

FIG. 19 is a schematic side view for explaining the operation of the second conventional example.

FIG. 20 is a schematic perspective view showing a magnetic head swinging device in a third conventional example.

FIG. 21 is a schematic side view for explaining the operation of the third conventional example.

[Explanation of symbols]

1 First magnetic head 2 Second magnetic head 3 Magnetic head base 4 Left connecting member 5 Right connecting member 6 Center connecting member 7 Bimorph element 8 Fixing base 11 Electrode 12 Groove provided in the bimorph element 13 Bimorph Groove 20 provided in the element Left bimorph beam 21 Center bimorph beam 22 Right bimorph beam

Claims (2)

[Claims] 1. A magnetic head base that holds a magnetic head, and a plurality of connecting means that have a plurality of beams and elastically connect the magnetic head base and the plurality of beams. It consists of a rocking means for rocking the base in the thickness direction of the magneto-magnetic head, and a fixing means for making the rocking means into a cantilever shape. A magnetic head swinging device comprising means for making the height of at least one beam in the swinging direction different from the height of the other beams in the swinging direction. 2. A magnetic head base that holds a magnetic head, and a plurality of connecting means that have a plurality of beams and elastically connect the magnetic head base and the plurality of beams. It consists of a rocking means for rocking the base in the thickness direction of the magnetic head, and a fixing means for making the rocking means into a cantilever shape, and at least one of the plurality of connecting means has a longitudinal side beam. A magnetic head rocking device that does not overlap in direction.