JP2516889Y2 - Driving device for magnetic head - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head driving device.

[0002]

2. Description of the Related Art A video tape recorder (VTR) is a typical example of a magnetic recording / reproducing apparatus for recording / reproducing information signals by using a rotary magnetic head on a magnetic tape. It is well known that the current VTR has been greatly improved in image quality and functions due to the dramatic progress from the development to the present. The VTR is currently under development. On the other hand, a VTR that records and reproduces an information signal on a magnetic tape by using a rotating magnetic head is used for recording a television broadcast program or recording a video signal captured by a television camera. It is generally used for recording images, but paying attention to the fact that the magnetic tape in a VTR has a large storage capacity,
TR is, for example, a storage device in a digital information processing device,
Attempts have also been made to use it as one of the other components.

By the way, a VTR is used as a component in a digital information processing apparatus, for example, "an external auxiliary storage device of a computer" or "an image of computer graphics is sequentially recorded at the end of calculation and is continuously reproduced. When used in a "moving device for moving picture" or the like, an information signal may be recorded on a magnetic tape in a recording mode such that one recording trace ((1 track) to several tracks is a unit). Therefore, in order to use the VTR as a constituent member of a digital information processing apparatus, the information recording operation performed in units of, for example, one track to several tracks as described above is also highly stable and highly reliable. VT in which information signals are recorded and reproduced by using a rotary magnetic head on a magnetic tape. In R, when recording on a specific track on the magnetic tape or rewriting the recorded content recorded on a specific track on the magnetic tape, pre-roll is performed from the planned recording start position. Before rewinding the magnetic tape, the magnetic tape is fast-forwarded from the rewound position at the time of recording to pass the planned recording start position at a predetermined tape feeding speed, and then the predetermined number of tracks from the planned recording start position. The magnetic tape is stopped at the position where the recording should be performed by the control pulse and the rotational position control of the capstan motor, and the rotating magnetic head performs the recording on the stopped magnetic tape. It is well known that these two methods have been conventionally performed.

The above-mentioned method is a method which is carried out in the assembly recording / insert recording mode in the editing function of the VTR. In this method, the magnetic tape is wound every time recording is performed on the magnetic tape. Since it is necessary to repeat returning and feeding in the forward direction, it is not suitable in the case where frequent recording operations are performed because the mechanism of the tape running system and the magnetic tape are burdened. Since the position of the track on which recording is performed is determined by the relative movement between the traveling magnetic tape and the rotating magnetic head, it is difficult to set the position of the track with high accuracy. There are various problems such as not being able to shorten. In addition, the above-described method does not require the rewinding operation as required by the above-described method, and the recording operation is performed while the magnetic tape is stopped. The advantage is that it does not impose a heavy burden on the magnetic tape and the magnetic tape, and that it is easy to set the position of the track with high accuracy. However, when the recording operation performed by the rotary magnetic head is stopped, Since it is performed on the magnetic tape, the track pattern recorded and formed on the magnetic tape at that time corresponds to the rotation locus of the rotary magnetic head with respect to the magnetic tape running at a predetermined running speed. Since the track pattern to be recorded and formed will be different, a magnetic tape on which an information signal is recorded by this method is run at a predetermined running speed. The track do not accurately track the track by the rotary magnetic head, also that were recorded by the the method in case of reproducing while being,
It is difficult to record and use a track recorded and formed on a magnetic tape in a state where the track is formed on the same magnetic tape while being run at a predetermined running speed.

In order to solve the above-mentioned problems in the prior art, an information signal which is conventionally recorded and formed on a magnetic tape running at a predetermined running speed corresponding to the rotation locus of a rotary magnetic head. The recording trace of the information signal similar to the recording trace of the above is recorded and formed by the rotation locus of the rotary magnetic head with respect to the magnetic tape in a state where the recording tape is stopped after intermittently moving by a predetermined distance in the tape running direction. A drive device for controlling the rotational locus of the rotary magnetic head during the intermittent recording operation based on the position signal of the rotary magnetic head generated corresponding to the absolute position of the rotary magnetic head with respect to the tape reference edge of the magnetic tape ( A VTR equipped with an actuator) has been proposed. As a driving device for the rotary magnetic head described above, for example, Japanese Patent Publication No. Drive by electric over transducer constituted by using the electrostrictive material as disclosed in 18686 JP Alternatively, for example, Japanese 63 over 258,
A drive device (voice ill motor) using an electro-mechanical conversion element of an electrodynamic type as disclosed in Japanese Patent Publication No. 21 and Japanese Patent Application Laid-Open No. 63-173217 has been proposed. Further, in the drive device (voice-oil motor) using the electrokinetic electromechanical conversion element, the displacement can be made larger than that in the drive device using the electromechanical conversion element configured by using the electrostrictive substance. No high voltage is required for driving. There are advantages such as easy control.

FIG. 5 is a diagram showing an example of the configuration of a driving device using an electro-mechanical conversion element of the electrokinetic type disclosed in the above-mentioned Japanese Patent Laid-Open No. 63-25821, and FIG. It is a figure which shows an example structure of the drive device by the electrokinetic conversion element of the electrokinetic type disclosed by Kaisho 63-173217. In the drive device using the electrodynamic mechanical conversion element illustrated in FIG. 5, the magnetic head H
The base of the leaf spring 1 to which is attached is fixed to the fixed portion 6 via the washer 7 by the screw 5, and the movable coil 2 fixed to the leaf spring 1 has a current When flowing, the magnetic head H is displaced by being displaced in the direction of the coil axis in the magnetic gap formed by the magnetic path 3 and the permanent magnet 4. FIG. 6 is a vertical cross-sectional view showing a state in which the driving device using the electrodynamic electromechanical conversion element having the configuration as shown in FIG. 5 is mounted on the rotary drum (upper drum) 33. 6, 30 is a fixed drum (lower drum), 31 and 32 are rotary transformers, 3
Reference numeral 4 is a rotary shaft, and 35 and 36 are bearings.

Further, in the driving device by the electro-mechanical conversion element of the electrokinetic type illustrated in FIGS. 7A to 7C, H is a magnetic head, 8 and 9 are non-magnetic leaf springs, 10
Is a coil bobbin, 11 is a coil, 12, 16 and 17 are magnetic path members, 13 and 14 are permanent magnets, and 15 is a pole piece. The coil bobbin 10 around which the coil 11 is wound.
Is supported by non-magnetic leaf springs 8 and 9 near both ends of the magnetic path member 12 so as to be displaced in the coil axial direction in a magnetic gap formed between the pole piece 15. . The above-mentioned non-magnetic plate spring 8 is an annular one in which a supporting portion 8a of the magnetic head H is projectingly provided in a part thereof, and the outer peripheral portion of the annular portion is the magnetic path member 12,
It is fixed to the magnetic path member by being sandwiched between 16, and the supporting portion 8a of the magnetic head H projects outward from the cutout portion 18 so that the magnetic head H can contact the magnetic tape. The above-mentioned non-magnetic plate spring 9 is of an annular shape, and is fixed to the magnetic path member by sandwiching the outer peripheral portion of the annular part between the magnetic path members 12 and 17. The annular non-magnetic plate spring 9 described above is provided with a large number of arcuate punched portions so as to reduce the mechanical impedance. In the driving device using the electro-mechanical conversion element of the electrokinetic type illustrated in FIG. 7, when a current is applied to the coil 11, in the magnetic gap formed between the magnetic path member 12 and the pole piece 15. The coil bobbin 10 is displaced in the direction of the coil axis to displace the magnetic head H.

By the way, in the electromechanical conversion element constructed by using the electrostrictive substance described in the above-mentioned patent publication, the amount of warp of the electrostrictive substance shows a hysteresis characteristic, and the state of the warp of the electrostrictive substance is temperature. Changes due to the change in the cantilever type, the locus of displacement of the magnetic head becomes an arc because it is a cantilever type, and in the case of a cantilever of finite length, the contact state between the magnetic head and the magnetic tape becomes poor, etc. There are various problems. Also, in the drive device using the electro-mechanical conversion element of the electrodynamic type shown in FIG. 5 described above, since the leaf spring 1 to which the magnetic head H is attached is of a cantilever type, the locus of displacement of the magnetic head is In the case of a cantilever with a finite length, it becomes a problem that the contact state between the magnetic head and the magnetic tape becomes poor, and it is good because leakage magnetic flux from the magnetic circuit appears near the magnetic head. However, in the drive device using the electro-mechanical conversion element of the electrodynamic type shown in FIG. 7, the vicinity of both ends of the coil bobbin 10 is a non-magnetic plate spring 8, Since it is supported by 9, the magnetic head H can be displaced in parallel with the coil axis. However, the above-mentioned non-magnetic plate springs 8 and 9 are provided on the outer circumference of the coil bobbin 10 and the magnetic path members 12 and 16. , 1 Be made with complicated shape of the spring is required so as to have a sufficiently low compliance narrow portion between the inner circumference of.

However, since the spring having a complicated shape as described above vibrates in many vibration modes, the coil bobbin tends to move in a direction inclined with respect to the coil axis, and in addition, it vibrates in many vibration modes. It is difficult to use for actuators (driving devices) used for positioning servos that require good response up to high frequencies. Further, a part of the non-magnetic plate spring 8 is extended to support the magnetic head H.
However, since the displacement of the coil bobbin 10 causes the supporting portion 8a of the magnetic head H to be excited, the magnetic head H may vibrate. Therefore, as a magnetic head driving device which does not have the problems in the above-mentioned conventional magnetic head driving device, the present applicant's company previously described in Japanese Patent Application No. 2-254934, FIG.
As shown in (c), the yoke 19 and the yoke 19
One end of the coil bobbin 24 which is driven and displaced in the central axis direction of the coil 23 in the magnetic gap 22 formed between the permanent magnet 20 and the magnetic path member including the pole piece 21 provided in the inner space of The mounting portion 25 of the magnetic head H, which projects outward from the coil bobbin 24, is integrally formed with 24a, and the support shaft 26 integrally formed with the coil bobbin 24 is formed at the center of the coil bobbin 24 at its outer end. The portion 26a is provided so as to project from the other end portion 24b of the coil bobbin 24, and the one end portion 27a of the first support member 27 is fixed to the outer end portion 26a of the support shaft 26 and the first support portion The other end portion 27b of the member 27 is fixed to a first fixing portion provided at a position beyond the inner wall surface position of the yoke described above, and one end portion 24 of the coil bobbin 24 described above is further fixed. The second fixing portion 29 provided in the portion of the position beyond the inner wall surface position of the second yoke 19 and the other end 28b and the support member 28 having one end 28a on the side is fixed
A magnetic head driving device has been proposed in which the magnetic head H is fixed to the front end portion of the magnetic head mounting portion 25 which is fixed to the yoke 19 and projects from the cutout portion 41 of the yoke 19 to the outside of the yoke 19.

[0010]

In the proposed magnetic head drive device as illustrated in FIG. 8, the support member 2 that individually supports the coil bobbin 24 near both ends thereof is provided.
Since 7, 28 having a simple shape and a sufficiently long shape is used, it is also possible to displace the magnetic head H in parallel with the coil axis with a large amplitude, which is preferable in the frequency band used. Even if the magnetic head H is driven with a large amplitude displacement, the contact state between the magnetic tape and the magnetic head H does not deteriorate, but it does not protrude from the coil bobbin 24. With respect to the magnetic head H fixed to the tip of the mounting portion 25 of the magnetic head H fixed to the one end 24a of the coil bobbin 24 in such a manner, leakage from the magnetic circuit through the notch 41 of the yoke 19 The problem was that the magnetic flux had an adverse effect.

FIG. 9 is a diagram for explaining the mode of generation of leakage magnetic flux from the magnetic circuit. In FIG. 9A, 37 is a yoke, 38 is a permanent magnet, and FIG. 9B is 37. , 40 is a yoke, 38 is a permanent magnet, and 39 is a pone piece. As shown in FIG. 9A, the conventional magnetic head drive device as shown in FIG. 5 is constructed as shown in FIG. 6 in which the magnetic path is opened. When used by being mounted on the rotary drum 33 as shown in FIG. 9, a large amount of leakage flux such as the leakage flux from the magnetic circuit shown in FIG. Will be given. On the other hand, like the magnetic path illustrated in FIG.
When a closed magnetic circuit is formed through an air gap,
Although a large amount of leakage magnetic flux such as the leakage magnetic flux from the magnetic circuit shown in FIG. 9A is not generated, some leakage magnetic flux is generated from the void portion to the outside. Therefore, also in the conventional and already proposed magnetic head driving devices having the magnetic path configurations as illustrated in FIGS. 7 and 8, the leakage magnetic flux from the magnetic circuit holds the magnetic head. Since a relatively large amount reaches the portion of the magnetic head H from the portion of the space provided for penetrating, the problem has been that the recording / reproducing operation is adversely affected.

[0012]

According to the present invention, a magnetic path member having a central hole is provided in the hollow portion of a hollow yoke having an opening at one end and a central hole at the bottom of the other end. In such a manner that the center hole of the magnetic path member communicates with each other, and the magnetic path member is disposed and fixed so as to be configured between the outer peripheral surface of the magnetic path member and the inner peripheral surface of the hollow portion of the yoke, In addition, the support shaft having one end of the coil bobbin that is driven and displaced in the direction of the central axis of the coil in the magnetic space described above is fixedly inserted into the central holes of the above-mentioned respective components, and Means for generating a magnetic flux interlinking with the coil wound around the coil bobbin in the magnetic air gap, and separate support portions on both ends of the support shaft projecting to the outside of the yoke. Attach one end of the member At the same time, each of the other ends of the support member is fixed to a fixing portion provided at a position beyond the inner peripheral surface position of the hollow portion of the yoke, and the center provided at the bottom portion of the yoke. A drive unit for a magnetic head in which a holder for a magnetic head is fixed to an end of a support shaft protruding from the hole to the outside of the yoke, and an opening is provided at one end, and a central hole is provided at the bottom of the other end. In the hollow portion of the hollow yoke having a permanent magnet having a center hole and a center pole having a center hole, the center hole of each of the above-mentioned constituent parts communicates with each other, and the permanent magnet and the center pole described above. A magnetic gap portion is arranged and fixed between the outer peripheral surfaces of both of them and the inner peripheral surface of the hollow portion of the yoke, and in the magnetic gap portion in the central axis direction of the coil. Coil bob that is driven and displaced A support shaft having one end fixed thereto is pierced through the center hole of each of the above-mentioned constituent parts in a loosely fitted state, and the support shaft has its both ends projecting to the outside of the yoke. One end of the support member is attached, and the other end of each of the support members is fixed to a fixing portion provided at a position beyond the inner peripheral surface position of the hollow portion of the yoke, and further described above. Provided is a magnetic head driving device in which a holder for a magnetic head is fixed to an end portion of a support shaft projecting to the outside of the yoke from a central hole provided in a bottom portion of the yoke.

[0013]

The permanent magnet having the central hole and the center pole having the central hole are assembled in the hollow portion of the hollow yoke having the central hole at the bottom so that the central holes of the above-mentioned respective constituent parts communicate with each other. The coil bobbin is driven and displaced in a magnetic gap formed between the outer peripheral surfaces of both the permanent magnet and the center pole and the inner peripheral surface of the hollow portion of the yoke. The support shaft to which one end of the coil bobbin that is driven and displaced in the central axis direction of the coil is fixed,
Through the center hole of each component described above in a loosely fitted state,
One end of each individual support member is attached to the both ends of the above-mentioned support shaft projecting to the outside of the above-mentioned yoke, and each other end of the above-mentioned support member is attached to the hollow portion of the above-mentioned yoke. It is fixed to a fixed part provided at a position beyond the inner peripheral surface position. The holder of the magnetic head is fixed to the end of the support shaft projecting to the outside of the yoke from the central hole provided in the bottom of the yoke, and the magnetic head is fixed to the tip of the holder of the magnetic head. Since the magnetic head is attached to the magnetic head holder provided on the side opposite to the open end of the magnetic path, no leakage magnetic flux is applied to the magnetic head.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a magnetic head driving device according to the present invention;
1 and 2 are vertical cross-sectional views of different embodiments of the magnetic head driving device of the present invention, FIG. 3 is an exploded perspective view of the magnetic head driving device shown in FIG. 1, and FIG. 4 is a magnetic device of the present invention. FIG. 6 is a partial vertical cross-sectional side view showing a state in which a head driving device is incorporated in a rotary drum. FIG. 1 is a vertical sectional view of different embodiments of the magnetic head driving device of the present invention.
2 and FIG. 3 showing the exploded perspective view, 41 is a hollow yoke whose one end is open, and 42 shown in FIGS. 1 and 2 is a hollow portion of the yoke 41. A central hole 41a is formed in the center of the bottom portion of the other end of the yoke 41. A magnetic path member having a central hole formed therein is fixed to the hollow portion 42 of the yoke 41 so that the central hole and the central hole 41a at the bottom of the yoke 41 communicate with each other. A magnetic gap is formed between the inner peripheral surface of the hollow portion 42 of the yoke 41 and the outer peripheral surface of the magnetic path member. A yoke 41 used to configure the magnetic gap portion so that a magnetic field for interlinking magnetic flux with a coil movably provided therein is generated in the magnetic gap portion. A magnetomotive force portion is provided at an appropriate portion in the magnetic circuit including the magnetic path member.
As the magnetomotive force portion, for example, a permanent magnet is used, or a magnetic path portion excited by an exciting coil is formed.

In the embodiment of the magnetic head driving device shown in FIGS. 1 to 3, it is assumed that the permanent magnet 43 is used as the magnetomotive force portion (in the implementation of the present invention, the magnetic Of course, the circuit may be configured as an outer magnet type). 1 and 2, in the hollow portion 42 of the yoke 41, a permanent magnet 4 having a central hole 43a is formed as a magnetic path member having a central hole.
3 and a center pole 4 having a center hole 44a
4 are fixed so that the central holes 43a, 44a and the central hole 41a at the bottom of the yoke 41 communicate with each other, and are used as the magnetic path member and the inner peripheral surface of the hollow portion 42 of the yoke 41. A magnetic gap is formed between the permanent magnet 43 and the outer peripheral surface of the center pole 44. Center hole 41a of the yoke 41 described above
And the center hole 43a of the permanent magnet 43 and the center pole 4
The support shaft 46 of the coil bobbin 45, around which the coil 45c is wound, can pass through the center hole 44a of the No. 4 in a loosely fitted state. The support shaft 46 of the coil bobbin 45 described above is After fitting in the hole formed in the one end portion 45a, the flange portion 46b of the one end portion 45a and the one end portion 45a of the coil bobbin 45 are fixed to each other by means such as adhesion. As described above, the support shaft 46 with the coil bobbin 45 fixed thereto has the center hole 44a of the center pole 44 and the center hole 43 of the permanent magnet 43 as described above.
a and the center hole 41a of the yoke 41 are penetrated.

In the magnetic head drive device shown in FIG. 1, the central hole 4 formed in the bottom of the yoke 41.
At one end of the support shaft 46 protruding from 1a, the support member 5
0 is fitted into a fitting hole 50b provided near one end thereof, and then a holder 49 of the magnetic head to which the magnetic head H is fixed is fitted, and then the holder 49 of the magnetic head. The support shaft 46 and the support shaft 46 are fixed to each other by screwing a screw 47 into a screw hole provided in the holder 49 of the magnetic head and a screw hole 46a provided in the support shaft 46. The other end of the member 50 is connected to the yoke 4
1, a screw hole 58 provided in the protrusion 41b at the bottom,
59 are screw holes 56, 57 formed in the support member 50.
After aligning, the plate 51 is placed on the
4, 55 are placed so as to match the screw holes 56, 57 formed in the support member 50, and the screws 52, 53 are screwed into the screw holes, whereby the bottom portion of the yoke 41 is secured. It is fixed to the protrusion 41b. Further, the other end of the support shaft 46 uses a fitting hole 60b provided near one end of the support member 60 as a screw hole, and a screw 48 is provided at the other end of the support shaft 46. By screwing into the hole, the other end of the support shaft 46 and one end of the support member 60 are fixed. Further, at the other end of the support member 60 described above, screw holes 66, 67 formed in the support member 60 are aligned with screw holes (not shown) provided in the projection 41c of the bottom of the yoke 41. Later, the plate 61
By making the screw holes 64 and 65 of the screw holes match the screw holes 66 and 67 formed in the support member 60, and screwing the screws 62 and 63 into the screw holes. It is fixed to the protrusion 41c on the bottom of the yoke 41.

Next, in the magnetic head driving device shown in FIG. 2, the magnetic head H is fixed to one end of the support shaft 46 projecting from the central hole 41a formed in the bottom of the yoke 41. After fitting the holding member 49 of the magnetic head, the fitting hole 50b provided near one end of the supporting member 50 is fitted, and then the holding member 49 of the magnetic head is provided. The holder 49 of the magnetic head, the support shaft 46, and the support member 50 are fixed to each other by screwing the screw 47 into the screw hole and the screw hole 46a provided in the support shaft 46, and the support described above is also provided. Member 50
After the screw holes 56 and 57 formed in the supporting member 50 are aligned with the screw holes 58 and 59 provided in the protrusion 41b of the bottom portion of the yoke 41, the other end of the plate body 5 is placed thereon.
1, the screw holes 54 and 55 of which are the support members 50 described above.
The screw holes 52 and 53 are screwed into the screw holes so that they are fitted to the screw holes 56 and 57 that are formed in the base plate, and are fixed to the protrusion 41b of the bottom portion of the yoke 41. The other end of the support shaft 46 uses a fitting hole 60b provided near one end of the support member 60 as a screw hole, and a screw 48 is screwed into a screw hole provided at the other end of the support shaft 46. By inserting, one end of the support member 60 is fixed to the other end of the support shaft 46. Further, the other end of the support member 60 described above is inserted into a screw hole (not shown) provided in the protrusion 41c of the bottom portion of the yoke 41.
After aligning the screw holes 66, 67 drilled in the plate member 61, the screw holes 64, 65 of the plate member 61 are aligned with the screw holes 66, 67 drilled in the support member 60. In this way, the screws 62 and 63 are screwed into the screw holes so as to be fixed to the protrusion 41c at the bottom of the yoke 41.

FIG. 4 shows a state in which the magnetic head driving device of the present invention constructed as described above is mounted on the rotary drum 33. As you can clearly see from Fig. 4,
Since the magnetic head H attached to the magnetic head driving device of the present invention is located far away from the leakage magnetic flux generating portion in the magnetic circuit of the magnetic head driving device,
The magnetic head H attached to the magnetic head driving device is not adversely affected by the leakage magnetic flux in the magnetic circuit in the magnetic head driving device.

[0019]

As is apparent from the above detailed description, in the magnetic head driving device of the present invention, a hollow yoke having a central hole at the bottom is provided with a permanent magnet having a central hole. A center pole having a center hole is arranged and fixed so that the center holes of the above-mentioned respective constituent parts communicate with each other, and the outer peripheral surfaces of both the permanent magnet and the center pole and the hollow portion of the yoke described above. The support shaft to which one end of the coil bobbin that is driven and displaced in the central axis direction of the coil is fixed so that the coil bobbin is driven and displaced in the magnetic gap formed between the inner peripheral surface of the One end of each individual support member is attached to each of the end portions of the support shaft that protrude outside the yoke, while allowing the support shaft to penetrate through the center hole of each component in a loosely fit state.
The other end of each of the supporting members is fixed to a fixing portion provided at a position beyond the inner peripheral surface position of the hollow portion of the yoke, and the yoke is inserted from the central hole provided at the bottom of the yoke. Since the holder of the magnetic head is fixed to the end of the support shaft projecting to the outside of the magnetic head and the magnetic head is fixed to the tip of the holder of the magnetic head, the magnetic head is opposite to the open end of the magnetic path. Since the magnetic head is attached to the holder of the magnetic head provided on the side, the magnetic flux is not given to the magnetic head. Therefore, in the magnetic head drive device of the present invention, the above-mentioned conventional example and the already proposed magnetic All the problems that have been a problem in the head drive device can be solved well.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a magnetic head driving device according to the present invention.

FIG. 2 is a longitudinal sectional view of a magnetic head driving device of the present invention.

FIG. 3 is an exploded perspective view of a drive unit for the magnetic head shown in FIG.

FIG. 4 is a partial vertical cross-sectional view showing a state in which the magnetic head driving device of the present invention is incorporated in a rotary drum.

FIG. 5 is a vertical cross-sectional view of a conventional example of a magnetic head driving device.

FIG. 6 is a vertical cross-sectional side view showing a state in which a conventional magnetic head driving device is incorporated in a rotary drum.

FIG. 7 is a vertical cross-sectional view of a conventional example of a magnetic head driving device.

FIG. 8 is a vertical cross-sectional view of a proposed magnetic head driving device.

FIG. 9 is an explanatory diagram showing a state of leakage magnetic flux from a magnetic circuit.

[Explanation of symbols]

41 ... Hollow yoke whose one end is open, 42 ... Hollow part in the yoke 41, 41a ... Central hole at the center of the bottom of the yoke 41, 43 ... Permanent magnet, 43a ... Central hole of permanent magnet, 44 ... Center Pole, 44a ... Center pole center hole, 45 ... Coil bobbin, 45c ... Coil, 4
6 ... Support shaft, 46b ... Collar part, 49 ... Magnetic head holder, 50, 60 ... Support member, H ... Magnetic head,

Front page continuation (72) Inventor Katsuyuki Suto 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Japan Victor Company of Japan, Ltd. (72) Inventor Shigeru Kawase 3-12 Moriya-cho, Kanagawa-ku, Yokohama, Japan In-house (56) References JP 63-25821 (JP, A) JP 63-152014 (JP, A) JP 2-333720 (JP, A) JP 2-15411 (JP, A) ) JP-A-59-160822 (JP, A)

Claims (2)

(57) [Scope of utility model registration request] 1. A hollow yoke having an opening at one end and a center hole at the bottom at the other end,
In the magnetic path member having a central hole, a magnetic gap portion is formed so that the central hole communicates with each other, and between the outer peripheral surface of the magnetic path member and the inner peripheral surface of the hollow portion of the yoke. The support shaft having the one end of the coil bobbin that is driven and displaced in the direction of the central axis of the coil in the magnetic gap is fixed in the central hole of each of the above-mentioned components. And a means for causing a magnetic flux interlinking with the coil wound around the coil bobbin to be generated in the magnetic gap, and protruding to the outside of the yoke in the support shaft. One end of each individual support member is attached to each of the two ends, and each of the other ends of the above-mentioned support members is provided at a position beyond the inner peripheral surface position of the hollow portion of the above-mentioned yoke. It sticks to the fixed part Further, the the driving apparatus of a magnetic head formed by fixing the holding member of the magnetic head from the bottom center hole provided in the end of the support shaft protruding outside the yoke the yoke. 2. A hollow portion of a hollow yoke having an opening at one end and a center hole at the bottom of the other end,
The permanent magnet having the central hole and the center pole having the central hole are arranged so that the central holes of the respective constituent parts described above communicate with each other, and the outer peripheral surface of either one or both of the permanent magnet and the center pole described above. A magnetic air gap is arranged and fixed so as to be formed between the outer peripheral surface and the inner peripheral surface of the hollow portion of the yoke, and is driven and displaced in the central axis direction of the coil in the magnetic air gap. A support shaft to which one end of a coil bobbin is fixed is penetrated in the center hole of each of the above-mentioned components in a loosely fitted state, and the support shaft has its both ends projecting to the outside of the yoke. While mounting one end of each individual support member, each other end of the support member is fixed to a fixed portion provided at a position beyond the inner peripheral surface position of the hollow portion of the yoke,
Further, the magnetic head driving device in which a holder of the magnetic head is fixed to an end of a support shaft projecting to the outside of the yoke from a central hole provided in the bottom of the yoke.