JPH0638284B2 - Rotating head device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a rotary head device for a VTR, and more particularly to a structure that is compact, compact, and has low cost and multi-function and high performance.

[Background of the Invention]

A conventional rotary head device for a VTR is disclosed in JP-A-53-55007.
Etc., there is no other structural example having a rotation actuating function in a structure having only a video head rotating function. An example of the structure of a motor that obtains a plurality of rotary powers from the same axis although the purpose is different is the structure described in Japanese Patent Publication No. 57-40574. This example is intended to drive the VTR capstan and the reel shaft simultaneously. The basic structure of the part that obtains the two powers is as follows. That is, on the same axis, the first rotation output shaft to which the first rotor is fixed and the second rotation output shaft to which the second rotor is fixed are provided.
The second rotor, which has a rotation output shaft of, is rotated by feeding power to the corresponding motor stator, and the second rotor electromagnetically coupled to this is also rotated. This is a strict configuration. Therefore, this structure is a configuration in which both the first and second rotary shaft outputs are obtained from the rotational force of the first motor rotor, and it is not possible to separately obtain each output and control is also difficult. In addition, since a unit consisting of one rotor and one rotating shaft is provided as a rotating unit and two units are provided as a unit rotating structure, in order to increase the concentricity of each rotating unit and the like, it is necessary to improve manufacturing accuracy. is necessary.

[Object of the Invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rotary head device having a small, lightweight and compact structure and having a plurality of functions capable of rotating the VTR mechanism in addition to rotating the video head.

[Outline of Invention]

In order to achieve the above object, in the rotary head device of the present invention, a DD motor for driving a video head is installed in a position above the bottom surface of the lower drum, and a second motor for coaxially rotating independently is provided. The feature is that the structure is such that the capstan shaft and reel shaft can be driven simultaneously under a compact, lightweight and compact device configuration. In particular, in the structure of the present invention, the central shaft is fixed directly or indirectly to the center of the bottom surface of the lower drum, the upper part is the housing rotating type video head rotating structure, and the lower part is the same rotating part for driving the capstan shaft and the like. With the engaging structure, it is easy to reduce the size, weight and size of the device, and it is also possible to easily realize high performance such as improvement of reduction of jitter, wow, flutter and vibration. In addition, the workability of assembling is improved and the cost can be reduced.

Example of Invention

The present invention will be described below based on examples. FIG. 1 is a first embodiment of the rotary head device of the present invention. The present embodiment is a so-called fixed shaft type middle drum rotating structure in which the central shaft is fixed and the second drum provided at the lower part of the upper drum is rotated. The central shaft 1 is fixed to the central portion of the bottom surface of the lower drum 3 by press fitting or the like. Then, the rotating portion including the drum 7 having the video head 8 mounted thereon is rotationally driven by the first flat driving motor incorporated inside the lower drum 3, and the second motor is flat like the first motor. It is concentrically provided around the center shaft 1 which is located on the lower surface of the bottom portion of the lower drum 3 by a motor and projects through the lower surface.
The upper drum 2 is indirectly fixed to the uppermost end of the central shaft 1 via a fixing disk 10. Video head mounted drum 7
Are fixed concentrically to the rotary structure 4. Rotating structure 4
Rolling bearings such as ball bearings are provided at two locations above and below the center of the bearing.
A and 5b are used and are rotatably engaged with the central shaft 1. A rotary-side yoke 15 of a flat-plane rotary transformer is fixed to the upper side of the drum 7 mounted on the outer periphery of the rotary structure 4 and the first motor is mounted to the lower side of the drum 7 mounted with the video head. Rotor (rotor magnet
18 and rotor yoke 19) are fixed. At the upper part, the fixed side yoke 14 of the rotary transformer is fixed to the fixed disk 10.
It is fixed to the underside of. On the other hand, the stator of the first motor is provided on the bottom surface of the lower drum 3 and faces the rotor. The stator comprises a coil 21, a stator yoke 22, a wiring board 25, a position sensor 40, a video head rotation position detection sensor (tack sensor) 41 and the like. The video head position detection signal source (tack signal source) 50 provided on the outer periphery of the lower end portion of the rotary structure is composed of a magnet having a small size, and is provided at the same axial height position as the tack sensor 41. The video head mounting drum 7 has a shape having an annular convex portion on the outer peripheral portion so that a dynamic balance correcting weight can be easily attached to the inner peripheral concave portion. The substrate 28 fixed to this is for connecting the terminal of the video head 8 and the terminal of the rotary transformer 15. A terminal of the rotary transformer 14 is connected to the upper surface of the upper drum 2 fixed to the upper surface of the fixed disk 10, and a substrate 29 for connecting to a video signal processing electronic circuit separately provided outside is fixed. 36
Is a connecting lead wire, 30 connector, to the electronic circuit. A shield case 20 made of a magnetic material is fixed to the inner surface of the drum on the outer circumference of the rotor of the first motor.
The leakage magnetic field of is absorbed here. The preload metal fitting 6 is for applying a preload between the bearings 5a and 5b to eliminate play between the bearings 5a and 5b. A first electric motor is controlled and fed from a driving electronic circuit to rotate a first rotating portion including a video head 8, and the head is slidably scanned on a video tape surface running on a side surface of a drum to record a video signal. ·Reproduce.

The second motor provided on the lower surface of the lower drum 3 is also a magnet
18 ', stator coil 21', stator yoke 22 ', wiring board
The structure of the electromagnetic parts such as 25 'and sensors is almost the same as that of the first motor. The stator of the second motor is fixed to the lower drum 3 on the surface of the lowermost surface 200, and the rotor magnet 1
The magnetic pole surface of 8'is facing upward and is opposed to this. A pulley 60 is provided at the center lower end portion of the rotor yoke 19 'of the rotor of the second motor so that the belt 150 can transmit the power to other portions. Further, an annular recess is provided on the outer peripheral portion of the yoke 19 'so that a dynamic balancing weight can be attached thereto. 51 is a plain bearing boss. By supplying electric power from the drive electronic circuit through the lead wire 35 ', this second motor is rotated and rotational power is taken out independently of the first motor above and the other mechanism of the VTR is rotationally driven. According to the rotary head device having the structure of the present embodiment, (1) a VTR set having a small, lightweight and compact structure is provided because the video head rotating motor and the VTR driving motor for other units are provided on the central shaft fixed to the center of the lower drum. Can be configured. (2) Since the central axis is fixed, there is little vibration when the motor rotates. In addition, because one axis is used,
It is easy to assemble the second motor and the rotating parts with high accuracy. In particular, the first and second independent rotary motors can be easily arranged at extremely close positions. The rotation stability is also high. (3) Second
Since it is possible to reduce the number of parts and the number of assembling steps including the load system driven by the motor, it can be manufactured at low cost. (4) Since the second motor is provided on the lower surface of the lower drum in comparison with the case where the second motor is provided separately in the other portion, the mounting strength and accuracy can be extremely increased. This is particularly advantageous in the case of a thin chassis structure. (5) V
Since a plurality of motors required for TR can be housed in a small space in the same place, magnetic leakage due to these motors can be easily shielded and reduced. (6) Since the rotating parts are installed close to each other on the same axis sharing the fixed part, it is not necessary to replace or re-install the jig or replace the testing machine during the dynamic balance test work of each rotating part. Therefore, efficient work is possible. (7) When the load rotating body connected to the second motor is deceleratingly driven to rotate at a constant speed, the second motor rotates at a high speed, so that the frequency signal generator for speed control (FG) can have a low rate and high accuracy. Moreover, since the rotation inertia converted into the load rotating body axis can be greatly increased, the performance of the servo system can be improved and the rotation unevenness can be suppressed to a low level. Therefore, a high-performance VTR with low jitter and low wow and flutter can be realized. (8) Since the head rotating body is semi-closedly built in the space formed between the upper drum and the lower drum, noise during rotation can be masked and greatly reduced. Further, since the surface area of the rotating portion can be reduced, air friction can be reduced and noise (wind noise) and loss (wind loss) due to this can be reduced. (9) Since the shaft is fixed structure, there is no torsional vibration of the shaft, and uneven rotation due to this can be eliminated. (10) Since the rotating part driven by the first motor can be made small, lightweight, and low in inertia, the amount of dynamic imbalance of the rotating part can be reduced and the vibration due to this can be reduced. Also, the startup start-up time can be shortened. (11) Since the bearing is not directly connected to the lower drum, the vibration of the lower drum can be reduced to a low level. (12) The entire device can be made thin because the structure can shorten the distance between the axes, and
Since preload applied to the bearing during assembly can be reduced, bearing friction can be reduced and power consumption can be reduced. (13) Since the upper drum is a fixed structure, the disturbance factor of the upper drum given to the running tape is extremely small and small. Therefore, tape vibration can be reduced and wow, flutter, and jitter can be reduced and improved. (14) The upper drum is fixed, and the narrow video head mounting drum located below this is rotated to prevent lifting of the video tape, resulting in less head chip protrusion and good head touch even under low tape tension. And a stable high head output can be obtained. Further, it is possible to improve the damage of the tape surface and the wear of the head. Furthermore, since there are few restrictions on the shape, size, and material of the surface of the upper drum, the drum on which the video head is mounted, etc., these can be easily processed at low cost. (15) Since the upper side drum supporting member such as the coupler is not provided on the side surface of the drum at all, the tape winding angle can be easily expanded, and therefore the drum diameter can be reduced to achieve the downsizing. (16) Since the upper drum is fixed, a lead structure for regulating the tape running posture can be provided on the side surface of the upper drum or the like, or another structural piece can be attached. (17) Since the annular convex portion is provided on the outer peripheral portion of the video head mounting drum, the dynamic balancing work can be efficiently performed. The outer peripheral edge of this convex portion can be used as a place to hang the drive belt of the balance testing machine.
There are various advantages such as.

FIG. 2 is a diagram of a second embodiment of the rotary head device of the present invention, in which a plurality of (two) second motors are provided below the lower drum 3.
This is a configuration example in the case of. The mounting structure of the shaft 1, the upper and lower drum structures, the structure of the video head mounting drum 7, the first motor structure, etc. are all the same as in the first embodiment. By providing two second motor parts as in this embodiment, it is possible to obtain two or more rotational powers independent of this part. The rotor of the motor arranged on the lower side of the second motor has a shape protruding toward the tip of the shaft 1 in order to reduce the diameter of the pulley 60 '. The tip of the shaft 1 has a stepped shape, and the bearing is a slide bearing, and a slide bearing boss 51 'is engaged with this portion.

FIG. 3 is a diagram of a third embodiment of the device of the present invention, which is an example of a structure in which the bottom portion of the lower drum 3 for fixing the motor stator is divided into separate pieces (motor fixing pieces) 170. The stators of the first and second motors are fixed to the front and back surfaces of this motor fixing piece 170.
The central shaft 1 is fixed to the center of the main fixing piece 170 by press fitting or the like. According to the structure of this embodiment, the shaft 1, the first and second motor parts, the video head 8, the drum 7 for mounting the same, the rotary transformer, etc. are all preliminarily mounted on the fixed piece 170 and can be assembled on the fixed piece 170 to be assembled. Even the dynamic balance test and rotation performance test can be performed in this state before the lower drum 3 is assembled, and the accuracy of the motor, head, and other parts, performance check, correction, and replacement can be easily performed, and finally the lower drum 3
The state of being incorporated into can be finished in a highly adjusted state.

FIG. 4 is a diagram of a fourth embodiment of the device of the present invention, which is an example of a structure in which the stator yokes of the first and second motors are integrated. Wiring boards 25, 25 'of the stator coils 21, 21' of the first and second motors are provided on both front and back surfaces of the stator yoke 22. According to this structure, it is possible to realize a thinner structure. Similar to the case of the third embodiment, the stator yoke 22 can be used as a base for substantially full assembly. The improvement effect of the assembling and adjusting work is almost the same as that of the third embodiment.

FIG. 5 is a fifth embodiment of the device of the present invention, which is an example of the structure in which the second motor is divided into two parts, that is, the upper and lower ends of the fixed shaft 1. According to this structure, the rotational driving force can be obtained from the upper portion. The stator yoke 22d 'may be fixed to the upper surface of the upper drum 2, or the upper surface of the upper drum may be made of a magnetic material and used as it is as the stator yoke.

FIG. 6 is a sixth embodiment of the device of the present invention, in which the upper drum 2
Is not fixed to the tip of the shaft 1 but fixed to the lower drum 3 by a coupler 210 provided on the side surface. In this structure, since the mass of the tip of the shaft 1 is extremely small, the natural frequency of the shaft 1 can be increased and the resonance with respect to rotational disturbance can be reduced and relaxed.

FIG. 7 shows a structural example in which a fluid dynamic bearing is used for the bearing portion. Multiple V-shaped shallow grooves (group) on the surface of shaft 1
190, and apply a lubricant such as grease to the housing boss 195
It is a structure filled between and. When the rotary structure 4 is driven by the first motor (counterclockwise in this case when viewed from above), the lubricant flows into the group 190 at a high speed to generate fluid dynamic pressure, and the housing boss 195 is radiused from the surface of the shaft 1. Push up in the direction. If a group such as a spiral shape is also provided on the surface of the thrust bearing piece 185 in the direction of concentrating the centers thereof, a fluid dynamic pressure similar to the above causes a force to push up the housing boss 195 also in the thrust direction generated here. . In this way, the rotary structure 4 is supported on the shaft 1 in a non-contact state.
By using the bearing of this structure, it is possible to eliminate contact rolling vibration of balls such as that in a ball bearing, so that a low vibration device can be realized. As a motor structure for reducing the friction of the thrust portion, a radial gap type motor is suitable for the first motor.
The bearing of the second motor uses a slide bearing. A small-diameter ball 65 is used in the thrust portion to reduce the thrust friction in this portion as well.

FIG. 8 is a diagram of a seventh embodiment of the apparatus of the present invention, in which a video head 8 is mounted on the lower surface of the upper drum 2 and is fixed to a rotary structure 4 which is rotationally engaged around a shaft 1 to rotate the whole. The so-called upper drum rotating type structure. The shaft 1 is fixed to the center of the bottom surface of the lower drum 3 as in the case of each of the above embodiments. A fixed disk 10 is fixed to the upper end of the shaft 1, and a fixed yoke 14 of the rotary transformer, its terminal connection board 29, and an electromagnetic field shield conductive plate 85 are fixed. On the surface of the substrate 29, an IC 80 of a video signal processing electronic circuit such as an amplifier and an electronic component 81 are fixedly connected. The structures of the first and second motor parts are the same as those in the above-mentioned respective embodiments. According to this structure, it is possible to realize an upper drum rotary type device having an improved S / N ratio of a video signal.

FIG. 9 is a view of an eighth embodiment of the device of the present invention, which is an upper drum rotating type structure using a fluid dynamic bearing. Thrust bearing piece
185 is provided in contact with the tip of the shaft 1. The rotary transformers 14 and 15 have a cylindrical shape and are provided on the inner peripheral portion of the first motor. In the second motor, a thrust piece 45 is provided on the bearing portion to receive the thrust load. According to this structure, the vibration can be reduced, and even when the video head 8 is replaced, the work can be efficiently and easily performed without removing the rotary transformers 14 and 15 regardless of this.

FIG. 10 is a ninth embodiment of the device of the present invention, in which the shaft 1'of the second motor provided below the lower drum 3 is separated from the upper first motor shaft 1 to form a rotary structure. It is an example of the structure. A slide bearing boss 51b and a bearing 5 are provided below the lower drum 3.
c is fitted and the rotary shaft 1'is inserted therein. A second motor rotor in which a pulley 60 is integrated is fixed to the tip of the rotary shaft 1 ', so that it can rotate integrally.

FIG. 11 is a diagram of a tenth embodiment of the apparatus of the present invention, in which the lower drum 3
Bearings 5a and 5b are provided at the center of the shaft 1, and the shaft 1 is rotatably inserted and engaged with the bearings. First motor and video head mounted drum 7 or upper drum 2 driven by the first motor
(All omitted in the figure) etc. are fixed to the shaft. Lower drum 3
The structure of the second motor, the shaft 1 ', and the rotor portion fixed to the shaft, which are provided below, is similar to that of the ninth embodiment (FIG. 10).

FIG. 12 is a diagram of an eleventh embodiment of the device of the present invention. In addition to the video head 8 and a rotating part which is fixed by the first motor, a concentric subordinate rotating part electromagnetically coupled to the video head 8 is also provided. It is a structural example which rotates together. In the figure, 118 is a multi-pole eddy current force generating magnet, 119 is a yoke, 120, 121.
Is a shield case, and 9 is a second rotating drum. When the rotor 4, the video head 8, the video head mounting drum 7 and other rotating parts are rotated by the first motor, the overcurrent force generating magnet 118 fixed to the tip of the rotating structure 4 also rotates integrally.
An eddy current is generated on the lower surface of the second rotary drum 9 facing the magnetic pole surface, and an eddy current force is generated there by interaction with the magnetic flux. Therefore, the eddy current force generating magnet 118 of the 22nd rotary drum rotates in the same direction as the magnet 118 with a constant slip. Shield cases 120 and 121 are magnets 118
This is to prevent magnetic field leakage. The upper drum 2 is fixed to the tip of a shaft 1 fixed to the bottom surface of the lower drum 3.
The second motor and pulley 60 are provided below the bottom surface of the lower drum 3. According to the structure of this embodiment, the upper drum 2
Since a second rotating drum 9 that rotates at a low speed is provided below the tape, when the tape runs on the surface of these drums,
Since a smooth running force without torque ripple can be given to the tape even on the surface of the rotating drum 9, the driving force and the tape tension of the tape running system can be reduced, and at the same time, the tape vibration can be greatly reduced for smooth running. realizable.
In addition, even with thin tape or the like, smooth normal running can be achieved by eliminating sticking to the drum surface.

FIG. 13 is a diagram of a twelfth embodiment of the present invention, and this structure is an example of a structure in which a third motor is provided as a drive source of the second rotary drum 9 unlike the eleventh embodiment (FIG. 12). 218 is a rotor magnet, 219 is the same yoke, 221 is a stator coil, 222 is the same yoke, and 220 is a shield case. On the lower surface of the upper drum 2, a motor stator (stator coil 221, stator yoke 2
22, the wiring board 34, etc.) are fixed, and the rotor (rotor magnet 218, stator yoke 219, etc.) is fixed on the upper surface of the second rotary drum 9 facing the same. Power is supplied to the coil to apply a driving force to the magnet 218 to rotate the second rotary drum 9. According to the structure of this embodiment, the speed of the second rotary drum 9 can be kept constant regardless of the load torque, and this speed can be freely selected and varied according to the running conditions and the like. Therefore, the tape running performance can be further improved as compared with the case of the eleventh embodiment. In addition, it can handle various tapes running without problems.
Since the load on the first motor for rotating the video head is also reduced, the vibration and unevenness of rotation of the motor can be suppressed to a low level, resulting in low jitter,
You can easily achieve high performance with low wow and flutter.

FIG. 14 is a diagram showing an example of a load drive system using the rotary head device of the present invention, (a) is a side view, and (b) is a schematic plan view. This configuration is an example in which the capstan shaft 70 is used as the first load for deceleration driving. The pulleys 60 and 61 are connected by a belt 150. The pulley 61 has a capstan shaft 70 fixed to the center thereof and a second pulley 62 fixed to the back side thereof. A second belt 150 'is hung here and further connected to another second load. Pulley 61 vs. pulley 60
The diameter of is equal to or larger than several times, and 60 is rotated at several times the number of rotations of the pulley 61. According to such a capstan shaft load drive system, the rotational speed of the drive motor (second motor) can be increased, so that the speed control signal generating FG can be at a low rate. Therefore, the accuracy of the FG signal can be made high. Also, as the apparent rotation inertia of the capstan shaft, the inertia of the second motor rotor is also increased to the value corresponding to the reduction ratio and added to the inertia of the pulley 61, so that the rotation inertia of the capstan shaft is apparent. The value is extremely large. Therefore, both the improvement of the FG accuracy and the increase of the inertia can significantly improve the servo controllability of the capstan shaft rotation.

FIG. 15 is a diagram showing an example of a load drive system using the rotary head device of the present invention, (a) is a side sectional view, and (b) is a plan view. This configuration is an example of a structure in which two load shafts 90 and 90 'are simultaneously driven by two second motors provided below the lower drum 3. The load shafts 90 and 90 'may be reel shafts or the like.
According to this structure, the high-performance rotation characteristics of the load shafts 90 and 90 'can be obtained in a more compact form including the load shaft, as in the embodiment shown in FIG.

In the above-mentioned embodiments, flat motors are used as the first and second motors, but other cylindrical motors or iron core motors having lots may be used. In addition, place 1 (pulley etc.) where power is taken out from the second motor rotor.
Although one motor is provided, two or more structures may be used. Further, in addition to the motor rotor, a roller having no driving force may be separately provided in the same axis. Further, as the rotational power transmission method, a pulley, a belt, a gear, a roller, or other means or structure may be used. Furthermore the first
The outer diameter of the video head mounted drum driven by the motor may be smaller than that of the upper drum or the lower drum, and the running tape surface may not slide.

〔The invention's effect〕

According to the present invention, since the video head rotating motor and the rotating structure as well as the motor and mechanism for operating the other part of the VTR can be provided in a small size on the video head rotating center line of the drum, a VTR set having a small, lightweight and compact structure. Can be realized.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a rotary head device of the present invention, FIG. 2 is a sectional view showing a second embodiment, and FIG.
FIG. 4 is a sectional view showing a fourth embodiment, FIG. 5 is a sectional view showing a fifth embodiment, FIG. 6 is a sectional view showing a sixth embodiment, and FIG. FIG. 8 is a sectional view showing the seventh embodiment, FIG. 9 is a sectional view showing the eighth embodiment, and FIG. 10 is a ninth embodiment. 11 is a sectional view showing the tenth embodiment, FIG. 12 is a sectional view showing the eleventh embodiment, and FIG. 13 is a sectional view showing the twelfth embodiment. (a) and (b) are sectional views and plan views showing an example of a load driving method using the rotary head device of the present invention, and FIGS. 15 (a) and (b) are other examples of the load driving method. FIG. 4 is a cross-sectional view and a main part plan view showing 1 …… Center axis, 2 …… Upper drum 3 …… Lower drum, 4 …… Rotating structure 5a, 5b, 5c, 5d, 5e, 5f, 5g… Bearing 7 …… Video head mounted drum 8 …… Video Heads, 14, 15 ... Rotating transformers 18, 18 ', 18c, 18d ... Rotor magnets 21, 21', 21c, 21d ... Stator coils 22, 22 ', 22c, 22d ... Stator yoke 25, 25 ', 25c, 25d ... wiring board 60, 60' ... pulley 150, 150 '... transmission belt

Claims (1)

[Claims] 1. A rotary having a rotary member having a head and a rotary transformer in an intermediate portion between fixed upper and lower drums, and the rotary member being driven to rotate around a fixed central axis by a head rotating motor having a built-in drum. In the head device, the rotary transformer is arranged on the upper drum side with respect to the rotary member, and its fixed side yoke is fixed on the upper drum side, and the head rotation motor is arranged on the lower member with respect to the rotary member. The magnet magnetic pole surface of the rotor on the drum side faces the bottom surface direction of the lower drum, and the fixed central axis has a portion projecting to the outside of the lower drum, and the projecting portion has a coaxial shape. A rotary head device comprising a second motor that can be driven independently of the head rotation motor and that has a power transmission means and a rotating portion that can rotate around the fixed central axis.