JPH11203750A - Ball base assembly of magnetic recording and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ball base assembly which does not change the height of a guide pole in spite of wear of gears. SOLUTION: Both slant faces of the thread ridges of internal threads 8a disposed at a ball base PB and both slant faces of the screw ridges of external threads 27a are brought into pressurized contact with each other so as to bring the front ends of respective pins 28, 29 pressurized at their base ends in a direction perpendicular to the flanks of the shaft of a guide pole into pressurized contact with each other by means of a spring plate 30 fixed to the ball base PB by a screw 31 in regions 5a, 5b at two points on the outside of the region formed with the external threads 27a formed on the outer peripheral surface of part of the shaft 5 of the guide pole GP. Even the slant faces of the screw ridges of both threads 8a, 27a wear, the shaft of the guide pole is not displaced in its axial direction and, therefore, the height of the guide pole does not change and the shaft of the guide pole is merely displaced in a direction orthogonal with the axial direction described above. The height control of the guide pole GP is thereby exactly executed and the operation to correct the bending of the recording traces of a magnetic tape T is eventually correctly executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetic recording / reproducing apparatus,
In particular, a magnetic coil wound around a part of the drum peripheral surface by a rotating magnetic head provided so that a rotational trajectory surface is formed at a predetermined position with respect to a fixed portion of the body of the magnetic recording / reproducing apparatus. Recording and playback operations are performed on the tape,
The first and second guide poles which are individually arranged on the running path between the winding start side and the winding end side of the magnetic tape to be wound around a part of the drum circumferential surface described above. The height of the recording trace at the position near the first guide pole obtained based on the reproduction signal from the magnetic tape, and the bending information of the recording trace at the position near the second guide pole. Information about the height of the guide pole so that the closed loop automatic control operation of adjusting the recording trace of the magnetic tape to the rotation locus of the rotating magnetic head is performed by changing the height control signal generated using The present invention relates to a magnetic recording / reproducing apparatus including a generating unit and a height control mechanism including a driving source and a power transmission mechanism provided on a fixed portion of a body of the magnetic recording / reproducing apparatus.

[0002]

2. Description of the Related Art A magnetic tape wound around a part of a peripheral surface of a drum is run at a predetermined running speed, and a specific recording trace pattern (track pattern) corresponding to the rotation locus of a rotary magnetic head is obtained. ) Is formed on a magnetic tape to perform a recording / reproducing operation, and is widely used as a video tape recorder (VTR) or a video cassette recorder (VCR). The above-mentioned track pattern has a specific format for each magnetic recording / reproducing method employed in the magnetic recording / reproducing apparatus, but is formed to operate according to the same magnetic recording / reproducing method. Even if the magnetic recording / reproducing device of the same standard exists, due to the variation due to the existence of the allowable manufacturing error, and other causes,
Generally, the track patterns formed on the magnetic tape corresponding to the rotation locus of the rotary magnetic head for each magnetic recording / reproducing device are different from each other.

[0003] For the above-mentioned reasons, the track pattern formed on the magnetic tape is different for each magnetic recording / reproducing device. Therefore, the recorded magnetic tape recorded by the magnetic recording / reproducing device is used for recording. When recording / reproducing is performed by a magnetic recording / reproducing apparatus other than the magnetic recording / reproducing apparatus (during compatible recording / reproducing operation), good reproducing operation may not be performed. In particular, when a track pattern is formed by recording traces having a narrow recording trace width (track width) for high-density recording, serious trouble may occur during the compatible recording / reproducing operation.

For example, in recent years, by recording three recording traces having a recording trace width of 19 μm on a magnetic tape T simultaneously in parallel, it has become possible to record and reproduce so-called high-vision image information. New form of VTR
(A so-called W-VHS VTR) has been proposed. In the above-described VTR of the new type, two adjacent recording marks among three recording marks formed in parallel on the magnetic tape T at the same time. Are used for recording / reproducing a video signal by two rotating magnetic heads having azimuth angles in opposite directions, and the remaining one recording trace is used for recording an acoustic signal by another rotating magnetic head. Used for reproduction,
The after-recording is also made possible by the rotary magnetic head for recording and reproducing the acoustic signal.

[0005] Incidentally, since the allowable value of the bending in one recording mark in the above-mentioned VTR is set to about 7 μm, for example, when after-recording is performed by the compatible recording / reproducing operation, the recorded magnetic tape is not recorded. A maximum of 1 between the recording trace and the rotation locus of the rotating magnetic head
A shift of about 4 μm may occur. So now,
Considering the case where the displacement of 14 μm occurs between the recording trace of the recorded magnetic tape and the rotation locus of the rotary magnetic head as described above, in the above case, the recording trace of the acoustic signal on the recorded magnetic tape is considered. The rotary magnetic head for recording and reproducing the audio signal to be subjected to the after-recording is shifted from the recording track for recording the audio signal on the recorded magnetic tape by 14 μm toward the recording track for recording the video signal adjacent thereto. In addition, a portion having a width of 14 μm in a recording trace for recording a video signal having a recording trace width of 19 μm is overwritten by an audio signal for after recording, and as a recording portion of an original video signal, Only the portion having a width of 5 μm is left, and the quality of the reproduced video signal is degraded.

In order to solve the above-mentioned problems, it is only necessary to match the rotation trajectory of the rotary magnetic head with the recording trace of the magnetic tape T. Conventionally, in the open loop control circuit or the closed loop control circuit, The rotating magnetic head is tracked to the recording trace of the magnetic head by being driven and displaced by a magnetic head driving device configured using an electro-mechanical conversion element (for example, a voice coil motor, a bimorph of an electrostrictive element) used as an actuator. Let them do it. For example, as disclosed in Japanese Utility Model Publication No. 63-34126 and Japanese Utility Model Application Publication No. Sho 61-158633, the rotating drum on which the rotating magnetic head is mounted and the lower drum are integrally tilted so that the rotating head becomes magnetic. The recording trace of the tape T can be tracked. For example, as disclosed in Japanese Patent Application Laid-Open No. 60-115043, the height of the guide pole is changed by the stacked piezoelectric elements.
For example, as disclosed in Japanese Utility Model Laid-Open Publication No. 61-153151, a gear is fixed to a shaft of a guide pole having a thread portion, and the gear is rotated by a motor to change the height of the guide pole. Various solutions have been proposed.

However, since about two rotary magnetic heads can be mounted on a single magnetic head drive device having a small size, it is used, for example, for recording and reproducing acoustic signals by a so-called deep recording method. In addition, it is difficult to mount an audio head on the magnetic head drive device, and the magnetic head drive device is very expensive. Is difficult to use for consumer VTRs where
Further, the rotating head and the lower drum are integrally tilted as in the above-described solution, and the rotating head is moved by the magnetic tape T.
In the magnetic recording / reproducing apparatus which is capable of tracking the recording marks of the magnetic recording / reproducing apparatus, it is possible to perform the tilt correction satisfactorily, but it is difficult to perform the bending correction. The element is not practical because it can only obtain a displacement of a few microns with a driving voltage of several hundred volts, and it is not practical to provide a motor or a gear on a pole base that is moved at the time of loading operation. There was a problem that it was extremely difficult.

[0008] The applicant's company has proposed a magnetic recording / reproducing apparatus as disclosed in Japanese Patent Application Laid-Open No. 7-57351, ie, a magnetic recording / reproducing apparatus, which does not cause the above-mentioned problems in the conventional apparatus. Recording and recording on a magnetic tape wound around a part of the drum peripheral surface by a rotary magnetic head provided so that a rotational trajectory surface is formed at a predetermined position with respect to a fixed portion of the body of the reproducing apparatus. A reproducing operation is performed, and the magnetic tape to be wound around a part of the drum peripheral surface is separately provided on a traveling path between a winding start side and a winding end side around the drum peripheral surface. A screw provided on the shaft of the guide pole is screwed into a screw hole threaded on the pole base of the loading mechanism to be disposed, and the structure integrated with the lower flange of the guide pole is formed. The height of the guide pole can be changed when a rotational force is transmitted to a gear of the magnetic recording / reproducing apparatus from a driving source provided in a fixed portion of the magnetic recording / reproducing apparatus via a power transmission system using the gear. The first,
The height of the second guide pole is determined based on the reproduction signal from the magnetic tape. The information on the curvature of the recording trace at a position near the first guide pole and the information at the position near the second guide pole are obtained. A reference position sensor and a rotary encoder that generate information on the height of the guide pole and a body of the magnetic recording / reproducing device are configured to be able to be changed by a height control signal generated using the bending information of the recording trace. By a closed loop automatic control system including a drive source and a power transmission mechanism provided in the fixed portion, an operation is performed such that the recording trace of the magnetic tape is adjusted to the rotation locus of the rotating magnetic head. A magnetic recording / reproducing apparatus having the height control mechanism configured as described above, and other magnetic recording / reproducing apparatuses (for example, Japanese Patent Application No. 9-120152). It is proposed.

According to the magnetic recording / reproducing apparatus proposed by the present applicant company, even if the recording trace recorded on the recorded magnetic tape to be reproduced is curved, it can be detected based on the reproduced signal. By the automatic control operation of the closed loop performed using the bending information of the generated recording trace,
By changing the height of the guide poles individually arranged in the running path between the winding start side and the winding end side around the drum peripheral surface by the closed loop automatic control system, the recording trace is rotated by the rotating magnetic head. Since the track is matched, the recorded magnetic tape recorded by another magnetic recording / reproducing device can also be favorably reproduced.

In the above-mentioned proposed magnetic recording / reproducing apparatus, a guide pole is provided on a pole base of a loading mechanism which is individually arranged in a running path of a magnetic tape at a winding start side and a winding end side around a drum peripheral surface. The configuration example of FIG. 8 will be described below with reference to FIG. In FIG. 8, G
P is a guide pole, and SP is a tilt pole. The top view of the pole base PB shown in FIG. 8A illustrates the relationship between the guide pole GP, the inclined pole SP, and the magnetic tape T. FIG. FIG. 9 is a longitudinal sectional view taken along the line AA in FIG. 8A, and FIG. 8C is a longitudinal sectional view of a guide pole GP portion. Reference numeral 5 denotes a guide pole shaft, and the guide pole shaft 5 is inserted into a hole 6 formed in the pole base PB near the lowermost end thereof. The moving direction of the shaft 5 is guided.

A lower flange 7 having a gear 7g formed on a lower outer periphery thereof is fitted and fixed to the shaft 5 of the guide pole, and a gear 7g formed on the lower flange 7 is formed.
A screw 7a is formed on the outer peripheral surface of the boss. The above-described gear 7g is a driven gear that is rotated by meshing with a drive gear of a height control mechanism provided on a fixed portion side of a body of a magnetic recording and reproducing apparatus described later. Gear 7 described above
The screw 7a on the outer peripheral surface of the boss portion g is screwed into a female screw 8 provided on the pole base PB. The length of the female screw 8 is set to the screw 7a on the outer peripheral surface of the boss of the gear 7g.
When the guide pole GP 5 rotates, the guide pole GP is displaced in the direction of the center line of the shaft 5 when the guide pole GP 5 is rotated.

Reference numeral 11 denotes an upper flange. The upper flange 11 has a lower surface which is spaced from the upper surface of the lower flange 7 by a distance equal to the width of the magnetic tape. It is fixed to the shaft 5. A roller 12 is provided between the upper and lower flanges 7 and 11, and the roller 12 is rotatably inserted into the shaft 5 of the guide pole. A semicircular light shielding plate 13 used as a component of the position sensor is provided on the upper end surface of the protruding portion 11a of the upper flange 11.
However, the height of the guide pole GP is adjusted by a predetermined mounting phase so that the position detecting operation of the height position of the guide pole GP can be favorably performed, and is fixed by the screw 14.

In the above-mentioned magnetic recording / reproducing apparatus, the magnetic recording / reproducing apparatus is screwed to a pole base of a loading mechanism which is individually disposed in a running path of a magnetic tape on a drum peripheral surface at a winding start side and a winding end side. The height of the guide pole is changed by rotating the shaft of the guide pole in which the screw to be screwed is provided in the screw hole provided. However, there is always a gap between the female screw in the screw hole and the male screw screwed into it.
Therefore, the height of the guide pole cannot be controlled satisfactorily.

Therefore, in the magnetic recording / reproducing apparatus proposed previously,
(B) of FIG. 7 so that the male screw provided on the shaft of the guide pole and the female screw threaded on the pole base can be screwed together without any backlash to perform a rotating operation. As shown in FIG. 8, as shown in FIG. 8, the shaft of the guide pole is formed using an elastic body or a spring so that one of the slopes of the threads of the female screw 8a and the male screw 27a comes into contact with each other. Pressurization was applied in the length direction. That is, an elastic ring 10 (for example, a rubber ring) is press-fitted between the upper end 9 of the pole base PB and the lower surface of the gear 7g formed below the lower flange 7 in FIG. The gear 7g is constantly biased upward. Thereby, the screw 7a on the outer peripheral surface of the boss portion of the gear 7g formed on the lower flange 7 and the female screw 8 provided on the pole base PB are tightly screwed together without play. Thus, the gear 7g provided as a driven gear in the height control mechanism on the pole base side meshes with the drive gear of the height control mechanism provided on the fixed portion side of the body of the magnetic recording / reproducing apparatus. In addition to the drive rotation, the rotation is not caused by the external force applied as a disturbance.

[0015]

However, as described above, a preload is applied in the longitudinal direction of the shaft of the guide pole,
One of the slopes of the male screw provided on the shaft of the guide pole, the thread of the female screw 8 a screwed on the pole base, and the thread of the male screw 27 a of the shaft 5 of the guide pole contacted each other under high pressure. In the state,
If the contact portion has been worn for a long period of time, the guide pole G is used as a component of the position sensor.
Even if the semi-circular light shielding plate 13 provided on P has the same rotation phase, the height of the guide pole GP will be different, so that the height of the guide pole is accurately controlled. This causes a problem that the correction of the curvature of the recording mark on the magnetic tape cannot be performed well.

[0016]

SUMMARY OF THE INVENTION According to the present invention, there is provided a magnetic recording / reproducing apparatus in which a rotating magnetic head is provided such that a rotational trajectory surface is formed at a predetermined position with respect to a fixed portion of a body of a drum. The recording and reproducing operations are performed on the magnetic tape wound on a part of the surface, and the start and end ends of the magnetic tape to be wound on the part of the drum peripheral surface around the drum peripheral surface. The height of the first and second guide poles individually arranged on the traveling path of the recording track at the position close to the first guide pole obtained based on the reproduction signal from the magnetic tape. By changing the bending information and the bending information of the recording trace at a position near the second guide pole by a height control signal generated, the recording trace of the magnetic tape is recorded on the rotation locus of the rotary magnetic head. Close together Means for generating information on the height of the guide pole so that the automatic control operation of the loop is performed, a drive source provided on a fixed portion of the body of the magnetic recording / reproducing apparatus, and the drive source and the guide described above. A guide pole in a magnetic recording / reproducing apparatus having a height control mechanism including a power transmission mechanism in which a gear is used at least in part between a driven gear provided on a shaft of the pole , A pole base assembly in a magnetic recording / reproducing apparatus provided with means for applying a vertical preload to the side surface of the axis of the guide pole, and a body of the magnetic recording / reproducing apparatus A magnetic tape wound around a part of the drum peripheral surface by a rotating magnetic head provided so that a rotation locus surface is formed at a predetermined position with respect to the fixed portion of the drum. Record for,
A reproducing operation is performed, and the first and the first magnetic tapes to be wound around a part of the drum peripheral surface are individually disposed on a traveling path between a winding start side and a winding end side around the drum peripheral surface.
Among the second inclined pole and the first and second guide poles,
The height of the first and second guide poles is obtained based on a reproduction signal from a magnetic tape, and the information on the curvature of the recording trace at a position close to the first guide pole and the second guide The closed loop automatic control operation for adjusting the recording trace of the magnetic tape to the rotation trajectory of the rotating magnetic head is performed by changing the height according to the height control signal generated by using the bending information of the recording trace at a position close to the pole. Means for generating information on the height of the guide pole, a drive source provided on a fixed portion of the body of the magnetic recording / reproducing apparatus, and a driven source provided on the shaft of the drive source and the guide pole. A guide pole in a magnetic recording / reproducing apparatus having a height control mechanism configured to include a power transmission mechanism in which a gear is used at least in part between the gear and the gear. In the pole base assembly, a pressurizing means for applying a pressurization in a direction parallel to the running direction of the magnetic tape between the inclined pole and the guide pole and on the side surface of the axis of the guide pole is provided. Provided in a magnetic recording / reproducing apparatus.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of a pole base assembly in a magnetic recording / reproducing apparatus according to the present invention will be described below in detail with reference to the accompanying drawings. FIGS. 1 to 4 are perspective views showing a schematic configuration of a magnetic recording / reproducing apparatus provided with a pole base assembly in the magnetic recording / reproducing apparatus of the present invention. 1 to 4, DB is a drum base, and the drum base DB is fixed to a fixed portion of the body of the magnetic recording / reproducing apparatus. The drum base DB is also a component that functions as a fixing part of the body of the magnetic recording / reproducing apparatus. Dd is a lower drum fixed to the drum base DB, and Du is an upper drum. The upper drum Du and the lower drum Dd constitute a drum structure DA. Md is a drum drive motor provided with the rotor fixed to the upper drum Du. In the following description, it is assumed that the upper drum Du is a rotating drum.

1 is a substrate, and 2 is a drum structure DA.
The center axis 2 is fixed to the center of the lower drum Dd fixed to the drum base DB.
The upper drum Du is rotatably mounted on the center shaft 2 of the drum structure MA via a bearing. 3,4
Is a screw for fixing the stator of the drum motor Md to the substrate 1. H is a rotating magnetic head that rotates at a predetermined rotation speed in the gap G between the upper drum Du and the lower drum Dd. The rotating magnetic head H forms a rotation locus plane at a predetermined position with respect to a fixed portion of the body of the magnetic recording / reproducing apparatus. Needless to say, a required number of rotating magnetic heads H are used according to the magnetic recording / reproducing method applied to the magnetic recording / reproducing apparatus.

BC is a base catcher, and the base catcher BC is provided in the drum base DB. When the loading operation of the magnetic tape performed by the loading mechanism is completed, the magnetic tape is wound in a predetermined range on the outer peripheral surface of the upper drum Du and the lower drum Dd constituting the drum assembly DA. (FIGS. 2 and 4 show the state when the loading operation of the magnetic tape by the loading mechanism is completed, but the magnetic tape is not shown). The loading mechanism pulls out a magnetic tape housed in a tape cassette (not shown) at the time of the loading operation, and, when the loading operation is completed, the magnetic tape wound around a part of the drum peripheral surface. And a first pole base PB provided with a first guide pole GP and a slant pole (slant pole) SP, which are arranged on the traveling path on the winding start side around the drum peripheral surface in the first embodiment. I have.

The loading mechanism cooperates with the first guide pole during the loading operation to pull out the magnetic tape housed in the tape cassette and, when the loading operation is completed, A second guide pole provided in a state where the magnetic tape wound around a part of the drum peripheral surface is disposed on a traveling path on the end side of the drum peripheral surface and an inclined pole; Pole base PB. The first and second pole bases PB are fixed to, for example, a link constituting a loading mechanism, and are fixed by a guide rail (not shown) from the position of the tape cassette to the position of the drum structure DA. It is configured to be able to move along the moving path of the vehicle.

In a state where the loading operation of the magnetic tape by the loading mechanism (not shown) is completed, the upper drum D constituting the above-mentioned drum structure DA is completed.
u and a guide pole G for winding a magnetic tape around a predetermined range on the peripheral surface of the lower drum Dd.
P and the first and second pole bases PB provided with the pair of inclined poles SP are separate base catchers BC whose tip portions are provided corresponding to the respective pole bases PB. Combine with Thereby, the first and second pole bases PB at the time of completion of the loading operation of the magnetic tape by the loading mechanism are predetermined with respect to the fixed portion of the body of the magnetic recording / reproducing apparatus in all of the left-right direction and the up-down direction. It is set in a state where it exists at a spatial position having the specified positional relationship.

As described above, the loading mechanism has the pole base P provided with the guide pole GP and the inclined pole SP paired with the guide pole GP.
1 to 4 show one of the two pole bases, that is, a part of the drum peripheral surface when the loading operation is completed. Only the pole base PB on which the second guide pole and the inclined pole are provided, which are arranged in the running path on the end side of the drum peripheral surface of the wound magnetic tape, is shown. The pole base PB on which the first guide pole and the pair of inclined poles are provided is not shown. This is because the pole base PB on which the first guide pole and the pair of inclined poles are provided is not shown in the drawing because it exists on the side opposite to the drum structure DA in the drawing.

In the magnetic recording / reproducing apparatus shown in each of the drawings, a control mechanism for controlling the height of the first guide pole and a control mechanism for controlling the height of the second guide pole are used. The same structure as the mechanism is used. Therefore, in the following description of the present specification, in the state where the loading operation of the magnetic tape by the loading mechanism is completed, the traveling path on the end side of the winding of the drum peripheral surface of the magnetic tape wound around a part of the drum peripheral surface A pole base PB provided with a second guide pole placed at a predetermined position in the inside and a tilt pole paired with the second guide pole, and a mechanism for controlling the height of the second guide pole Is often described simply using terms such as the guide pole GP without distinction between the first guide pole and the second guide pole.

In the magnetic recording / reproducing apparatus shown in FIGS. 1 to 4, GP is a guide pole and SP is a tilt pole.
The guide pole GP provided on the pole base PB shown in FIGS. 1 and 2 together with the inclined pole SP is shown in FIGS. 5A and 5B, and in FIGS. 3 and 4. Inclined pole SP on pole base PB shown in
The guide pole GP provided together with is shown in FIGS. 5A and 6A are top views of the pole base PB, and FIGS. 5B and 6B are AA in FIGS. 5A and 6A. It is a longitudinal cross-sectional view of a line position.

Reference numeral 5 denotes a guide pole shaft. The guide pole shaft 5 is inserted into a hole 6 formed in the pole base PB near the lowermost end thereof. The moving direction of the guide pole shaft 5 is guided. The guide pole shaft 5
, A lower flange 7 having a gear 7g formed on a lower outer periphery is fitted and fixed. 27a is a male screw formed on the outer peripheral surface of a part of the shaft 5 of the guide pole. The gear 7g described above is a driven gear that is rotated by meshing with a drive gear 22 (FIGS. 1 to 4) of a height control mechanism provided on a fixed portion side of a body of a magnetic recording / reproducing apparatus described later. is there.

The male screw 27a formed on a part of the outer peripheral surface of the shaft 5 of the guide pole is provided with a pole base P
B is screwed into a female screw 8a provided in B. The length of the female screw 8a is set to be longer than the length of the male screw 27a formed on a part of the outer peripheral surface of the shaft 5 of the guide pole. The pole GP will be displaced in the direction of the center line of its shaft 5.

Reference numerals 5a and 5b in the drawing denote regions outside the region where the male screw 27a is formed on the outer peripheral surface of a part of the guide pole shaft 5, and the regions 5a and 5b include the pins 28 and 29 are crimped. That is, screw 3
Spring plate 3 fixed to pole base PB by 1
Due to 0, the distal ends of the pins 28, 29 whose base ends are pressed in a direction perpendicular to the side surface of the shaft 5 of the guide pole are pressed against the regions 5a, 5b. PP in the figure is the overall reference number of the pressurizing mechanism composed of the pins 28 and 29, the spring plate 30, the screw 31, and the like.

In the guide pole GP, 11 is an upper flange, and the upper flange 11 is arranged such that the lower surface thereof is spaced from the upper surface of the lower flange 7 by a distance equal to the width of the magnetic tape. The guide pole is fixed to the shaft 5. A roller 12 is provided between the upper and lower flanges 7 and 11, and the roller 12 is rotatably inserted into the shaft 5 of the guide pole. Projection 11a of upper flange 11
A semicircular light shielding plate 13 used as a constituent member of a position sensor PS described later is provided on an upper end surface of the guide pole GP in advance so that the position detection operation of the height position of the guide pole GP can be favorably performed. It is adjusted to have a predetermined mounting phase and fixed by screws 14. 24
Is a photo interrupter in the position sensor PS cooperating with the above-mentioned light shielding plate 13.

In FIGS. 1 to 4, Mg is a motor, and RE is a rotary encoder. As the rotary encoder RE, a rotary encoder having an appropriate configuration from among known various rotary encoders having a function of generating and outputting a pulse having information on the rotation direction of the rotation axis of the motor Mg and information on the rotation amount is provided. Is selected and used. The rotary encoder RE shown in each of the above-described drawings is shown as being constituted by a light-shielding blade 16 and a photo-interrupter 17 attached to the rotating shaft 15 of the motor Mg.

A gear 18 is fixed to the shaft 15 of the motor Mg in addition to the light-shielding blade plate 16 of the rotary encoder RE, and a gear 19 in a power transmission system is meshed with the gear 18. ing. Reference numeral 21 denotes a rotation shaft of the gear 19. The rotating shaft 21 has a gear 2
0 is fixed, and the gear 20 is meshed with the gear 22 fixed to the rotating shaft 23. The gear 22 is a drive gear of a height control mechanism provided on the fixed portion side of the body of the magnetic recording / reproducing apparatus.

The operation of the loading mechanism (not shown) causes the pole base PB to move along the predetermined moving path from the position of the magnetic tape cassette to the position of the drum structure DA, and the loading operation of the magnetic tape by the loading mechanism is performed. In the completed state, when the tip of the pole base PB is positioned by engaging with the base catcher BC provided corresponding to the pole base PB, the pole base PB is placed on the pole base side. A gear 7g provided as a driven gear in the height control mechanism is meshed with a drive gear 22 of the height control mechanism provided on the fixed portion side of the body of the magnetic recording / reproducing apparatus.

FIG. 9 is a diagram for explaining a manner of detecting a reference position (a reference height position of the guide pole GP) by the position sensor PS constituted by the light shielding plate 13 and the photo interrupter 24. , 25 is a light emitting element, and 26 is a light receiving element. In the illustrated example, the light emitting element 25 is used.
The position sensor PS is configured to generate a position signal when the light-shielding plate 13 enters and exits in the optical path from the light-receiving element 26 to the light-receiving element 26. A reflection type in which light reflected by the light shielding plate 13 is received by a light receiving element to generate a position signal may be used. Instead of an optical position sensor, for example, a position sensor constituted by a permanent magnet and a magnetic detection element (for example, a Hall element) may be used.

Light shielding plate 1 in position sensor PS described above
3 is attached to the upper end surface of the protrusion 11a of the upper flange 11 in the guide pole GP as described above.
When attaching the upper flange 11 of the upper flange 11 of the light shielding plate 13 to the upper end surface, the guide surface of the guide pole GP (the upper surface of the lower flange 7 of the guide pole, the lower surface of the upper flange 11 of the guide pole, the lower surface of the guide pole) When the magnetic recording / reproducing apparatus is in a state where the roller surface is at a predetermined regular height for ensuring recording / reproducing compatibility, the light-shielding plate 13 of the position sensor PS is rotated by the reference rotation. The position, that is, the moment when the light from the light emitting element 25 is received by the light receiving element 26 when the light goes out of the optical path between the light emitting element 25 and the light receiving element 26 disposed in the photointerrupter 24 so as to face each other. The light shielding plate 13 of the position sensor PS is attached to the upper end surface of the protruding portion 11a of the upper flange 11 by the screw 14 so that the position (see FIG. 9A) is reached.

By the way, the guide pole GP to which the light shielding plate 13 of the position sensor PS is attached is, as described above, a drive of the power transmission system in the height control mechanism provided on the fixed portion side of the body of the magnetic recording / reproducing apparatus. When the driven gear 7g in the height control mechanism provided on the loading pole side meshed with the gear 22 is driven and rotated,
Because it is configured to be able to move up and down,
The guide pole GP has a driven gear 7g and a driving gear 2
2 and the guide pole GP
Rotates when some rotational force is applied to
The guide pole GP may move upward and downward.

Then, the guide surface of the guide pole GP is
The light shielding plate 13 of the position sensor PS is set to a reference rotation position in correspondence with a state where the magnetic recording / reproducing apparatus is at a predetermined regular height position for ensuring recording / reproducing compatibility. After being attached to the guide pole GP, it is necessary to prevent the guide pole GP from rotating even if an external force acting as a disturbance is applied to the guide pole GP. The male screw 27a on a part of the outer peripheral surface of the shaft 5 and the female screw 8a provided on the pole base PB are perpendicular to the direction of the axis of the shaft 5 of the guide pole as illustrated in FIG. 7g, which is provided as a driven gear in the height control mechanism on the pole base side, is pressed in the direction of In addition to rotated I drive gear 22 meshes with a height control mechanism provided on the fixed portion side,
It does not rotate even when an external force is applied as a disturbance.

In the magnetic recording / reproducing apparatus shown in FIGS. 1 to 4, when the loading operation of the magnetic tape by the loading mechanism is completed, the magnetic tape wound around a part of the drum peripheral surface is wound around the drum peripheral surface. A first guide pole disposed at a predetermined position in a starting traveling path, and a traveling path on a ending end side of a drum peripheral surface of a magnetic tape wound around a part of the drum peripheral surface; The height of the lower flange 7 of each of the second guide poles disposed at predetermined inside positions is predetermined for the magnetic recording apparatus in order to ensure compatibility of the recording / reproducing operation. In the state where the magnetic recording / reproducing apparatus is in the reproducing mode, the height of the lower flange 7 of the first guide pole is added to the reproducing signal from the magnetic tape. The height is changed by a height control mechanism based on a height control signal generated using the bending information of the recording trace at a position near the first guide pole obtained as described above. The height of the lower flange 7 is controlled by a height control signal generated by using the bending information of the recording trace at a position near the second guide pole obtained based on the reproduction signal from the magnetic tape. By performing a control operation such that the recording trace of the magnetic tape matches the rotation trajectory of the rotary magnetic head by changing the mechanism, a good reproduction operation can be realized.

That is, the normal recording mark bend appearing on the recording mark of the recorded magnetic tape to be reproduced in the magnetic recording / reproducing apparatus is U-shaped or S-shaped, and the S-shaped bend of the recording mark is a drum. The height of the lower flange of the first guide pole, which is disposed at a predetermined position in the traveling path on the side of the winding start side of the drum around the magnetic tape wound on a part of the circumferential surface ( (Road position of magnetic tape)
And the height of the lower flange 7 of the second guide pole in a state where the magnetic tape wound around a part of the drum peripheral surface is disposed at a predetermined position in the traveling path on the trailing end side of the drum peripheral surface.
(The position of the running path of the magnetic tape) in opposite directions, that is, when one is raised, the other is lower, and so on. The first guide pole is disposed in the running path of the magnetic tape on the winding start side of the drum so as to perform such correction. And the height of the lower flange 7 between the magnetic tape and the second guide pole arranged in the running path on the end side of the winding of the drum peripheral surface,
By controlling with a control mechanism of a height to which a control signal obtained based on the information of the recording trace is given, a good reproduction signal free from the influence of the curvature of the recording trace can be easily obtained.

The envelope state of the reproduced frequency modulation wave signal obtained from the magnetic recording / reproducing apparatus in the reproducing mode is wavy corresponding to the U-shaped or S-shaped bent of the recording trace. Then, after detecting the reproduced frequency modulated wave signal by the amplitude detector, for example, a signal portion near the head of the envelope signal corresponding to each one recording trace sequentially output from the amplitude detector, Sampling is performed at a time position at which a signal portion near the end and an intermediate signal portion can be extracted, and sampling is performed from a signal portion near the head in the envelope signal corresponding to each of the above-described sequential recording traces. The height of the lower flange 7 of the first guide pole disposed in the traveling path on the drum start side on the drum peripheral surface is changed based on the detected signal and the signal extracted from the intermediate signal portion. And generates a height control signal having a magnitude and a direction to supply the control signal to the motor Mg of the height control mechanism of the lower flange 7 of the first guide pole.

Further, based on the signal sampled from the signal portion near the end and the signal extracted from the intermediate signal portion in the envelope signal corresponding to each of the recording traces in sequence, the drum peripheral surface is determined. A height control signal having a magnitude and a direction for changing the height of the lower flange 7 of the second guide pole arranged in the traveling path on the end side of the winding is generated, and the control signal is generated. The second guide pole is supplied to the motor Mg of the height control mechanism of the lower flange 7 of the guide pole. The magnitude of the signal sampled from the intermediate signal portion in the envelope signal corresponding to the reproduced frequency-modulated wave signal reproduced from one recording trace depends on the height of the first and second guide poles. Even if the height is changed, it does not change significantly. The information on the change in height can be easily obtained by comparing successive sample values on the time axis at the same position in the reproduced frequency modulated wave signal reproduced from each recording trace and the corresponding envelope signal. Is obtained. The height control signal can be generated by a control device including a microprocessor.

The different heights for changing the height of the lower flange 7 of the first and second guide poles to which the drive signal corresponding to the height control signal generated as described above is supplied. The motor Mg in the control mechanism of the above (1) is controlled by the drive signal corresponding to the height control signal having the magnitude and direction individually supplied to the signal in the forward (or reverse) direction in accordance with the signal. Rotate by the appropriate amount. The rotational force of the motor Mg is transmitted to the drive gear 22 via the gears 18, 19, 20 fixed to the rotary shaft 15, and transmitted to the driven gear 7g meshed with the drive gear 22. , The driven gear 7g rotates in the forward (or reverse) direction, whereby the guide pole G
P is displaced in the direction of the center line of the guide pole shaft 5, and the position of the lower flange 7 fixed to the guide pole shaft 5 is displaced upward and downward in accordance with the amount of rotation of the driven gear 7g. Will do.

In the magnetic recording / reproducing apparatus described above,
Shield plate 1 of position sensor PS obtained from position sensor PS
A signal corresponding to the reference rotation position of No. 3 and a pulse output from the rotary encoder RE and having information on the rotation direction and the amount of rotation of the rotation shaft 15 of the motor Mg are supplied to the control device, and the control described above is performed. First and second depending on the device
A control signal for the height of the guide pole can be generated, whereby the motor Mg of the height control device can be driven. Therefore, the lower flange 7 fixed to the shaft 1 of the first and second guide poles can be generated. (The height of the guide surface of the guide pole GP) can be easily set with high accuracy.

That is, the height of the guide surface of the guide pole GP fixed to the shaft 5 of the guide pole (the height of the lower flange 7) is at the reference rotation position of the light shielding plate 13 of the position sensor PS. Of the position sensor PS corresponding to the above-mentioned reference height and the amount of rotation of the light-shielding plate 13 from the reference rotation position. Thus, the reference height position of the guide surface of the guide pole GP can be determined from the output signal from the position sensor PS, and the amount of change in the height (time) from the reference height position of the guide surface of the guide pole GP. The movement amount) can be known from the number of output pulses of the rotary encoder RE. The height of the lower flange 7 fixed to the shaft 5 of the first and second guide poles (the height of the guide surface of the guide pole GP) is output when the height is at the reference height position. The counter is preset to a predetermined value by the output signal of the position sensor PS, and counts the number of pulses output from the rotary encoder RE provided on the motor Mg used to rotate the guide pole GP. It can be detected by counting.

When the magnetic recording / reproducing apparatus is manufactured, the height of the guide pole GP is set to a standard height (predetermined) in order to ensure compatibility between the magnetic recording / reproducing apparatuses during the recording / reproducing operation. (Regular height), but the guide pole shaft 5
The operation of setting the reference height position of the guide surface of the guide pole GP, in which the height of the guide surface of the guide pole GP can be changed by the rotation of, can be performed as follows, for example. That is, when setting the height of the guide pole GP, the magnetic recording / reproducing apparatus uses a standard tape (recorded magnetic tape in which there is no bend in the recorded trace).
Is mounted, and the motor Mg in the height control mechanism of the guide pole GP on the winding start side of the magnetic tape around the drum peripheral surface is
Rotate forward or reverse until a signal corresponding to the reference rotation position of the light shielding plate 13 is output from the position sensor PS, and the position of the guide pole GP in the height control mechanism on the winding start side of the magnetic tape around the drum peripheral surface. By the time when the signal corresponding to the reference rotation position of the light shielding plate 13 is output from the sensor PS,
The number of output pulses from the rotary encoder RE counted by the counter is preset to a predetermined value (for example, zero). The same applies to the height control mechanism of the guide pole GP at the end of winding the magnetic tape around the drum peripheral surface.

Next, the standard tape is run, and after the running state is stabilized, the reproduced frequency-modulated wave signal is detected by the envelope detection circuit. Sampling is sampled at a time position such that a signal portion near the head, a signal portion near the end, and a signal portion in the middle can be extracted from the envelope signal corresponding to each successive recording trace output from the envelope detection circuit and corresponding to each recording trace. And analog-to-digital conversion of the sample value is given to the CPU. The CPU detects the above-mentioned envelope signal and uses the motor Mg in the height control mechanism of the guide pole GP on the winding start side of the magnetic tape around the drum peripheral surface to control the guide pole on the winding start side of the magnetic tape around the drum peripheral surface. The height of the GP is changed over its variable range, and the envelope value that changes with the change in the height of the guide pole GP (counter value of the counter) is calculated and written to the memory. From the envelope signal obtained over the variable range of the height, a counter value indicating the state of the highest flatness is written to an external nonvolatile memory.

The same applies to the mechanism for controlling the height of the guide pole GP at the end of winding the magnetic tape around the drum peripheral surface. The counter value written in the external non-volatile memory as described above is determined by the magnetic recording / reproducing apparatus by the standard height of the guide pole GP (the regular height determined in advance for ensuring the compatibility of the recording / reproducing operation). Height).
Therefore, at the time of the recording operation of the magnetic recording / reproducing apparatus, if the height position of each guide pole GP is set corresponding to the counter value written in the external nonvolatile memory,
The height position of each guide pole GP is set to a predetermined regular height for ensuring compatibility of the recording / reproducing operation. Then, when the loading operation of the magnetic recording / reproducing apparatus is completed, each guide pole G
If the height position of P is always in the above-mentioned regular height state, the compatibility between the magnetic recording / reproducing devices can be kept good.

As described above, the guide pole GP in the state set at the reference height position is driven by the operation of the pressurizing mechanism PP to apply the guide pole GP even when an external force causing disturbance is applied. The guide pole GP of the conventional example described above with reference to FIG.
Also in the above, pressurizing is applied in the longitudinal direction of the shaft 5,
As exemplified in FIG. 7B, the pole base PB
Of the thread of the female screw 8a provided on the
The male thread 27a formed on the P shaft 5 was pressed against the thread slope.

Also in the conventional guide pole GP shown in FIG. 8, the slope of the thread of the female screw 8a provided on the pole base PB and the slope of the thread of the male screw 27a formed on the shaft 5 of the guide pole GP are crimped. Therefore, the shaft 5 can be prevented from rotating even when an external force acting as a disturbance is applied. However, as described above, the shaft 5 has the slope of the screw thread of the female screw 8a facing and crimped. If the slope of the thread of the external thread 27a is worn by the long-term use of the magnetic recording / reproducing apparatus, the shaft 5 is displaced in the longitudinal direction of the shaft.

As described above, the height of the guide pole GP depends on the rotational phase of the shaft 5 (semicircular light-shielding plate 13).
Of the guide pole GP even if the shaft 5 is displaced in the longitudinal direction due to the abrasion of the thread slope described above, as long as the rotation phase of the shaft 5 does not change. No change occurs in the height value of. Therefore, in the conventional guide pole GP illustrated in FIG. 8, the height control of the guide pole GP cannot be accurately performed with the long-term use of the magnetic recording / reproducing apparatus, and the standard guide pole GP at the time of the recording operation is used. Since the height changes, a standard track pattern cannot be recorded and formed on the magnetic tape.

However, in the pole base assembly in the magnetic recording / reproducing apparatus of the present invention, the regions 5a and 5b outside the region where the male screw 27a is formed on a part of the outer peripheral surface of the shaft 5 of the guide pole are provided. A spring plate 30 fixed to the pole base PB by a screw 31 presses the distal ends of the pins 28 and 29 whose base ends are pressed in a direction perpendicular to the side surface of the guide pole shaft 5. Therefore, the slope of the thread of the internal thread 8a provided on the pole base PB and the shaft 5 of the guide pole GP
As shown in FIG. 7 (a), the slope of the thread of the external thread 27a is a state in which both slopes of the thread of one screw are in contact with both slopes of the other thread. Are in a state of being pressed against each other.

For this purpose, the magnetic recording / reproducing apparatus has been used for a long time, and the slope of the thread of the female screw 8a provided on the pole base PB and the slope of the thread of the male thread 27a formed on the shaft 5 of the guide pole GP have been changed. Since the two slopes of each thread are similarly worn, even if the above-mentioned wear occurs,
Since the shaft 5 of the guide pole GP does not displace in the axial direction thereof, the height of the guide pole GP does not change, and the shaft 5 of the guide pole GP displaces in a direction orthogonal to the above-mentioned axial direction. Only. Therefore, the pole base assembly in the magnetic recording and reproducing apparatus of the present invention is:
Since the standard height set on the guide pole GP does not change even after long-term use, a standard track pattern is always recorded in a recording operation in which the height of the guide pole GP is set to the standard height. It can be formed.

The magnetic recording / reproducing apparatus illustrated in FIGS. 1 and 2 is a magnetic recording / reproducing apparatus constructed using the pole base assembly shown in FIG.
The magnetic recording / reproducing device illustrated in FIG. 4 is a magnetic recording / reproducing device configured using the pole base assembly illustrated in FIG. In the pole base assembly shown in FIG. 5 used in the magnetic recording / reproducing apparatus shown in FIGS. 1 and 2, a rotation shaft 23 of a drive gear 22 provided on a fixed portion side of the apparatus and a pole base assembly Pins 28 and 29 are provided near the intersection of the surface of the guide pole GP including the shaft 5 and the side surface of the standing portion of the pole base far from the rotation shaft 23 of the drive gear 22. A hole through which the screw 31 is inserted and a screw hole into which the screw 31 is screwed are provided, and the pressurizing mechanism PP is configured by the pins 28 and 29, the spring plate 30, the screw 31, and the like.

In the magnetic recording / reproducing apparatus shown in FIGS. 1 and 2 in which the pole base assembly having the structure shown in FIG. 5 is used, the operation of the pressurizing mechanism PP
In order that the two slopes of the thread of the female screw 8a provided on the pole base PB and the two slopes of the thread of the male screw 27a formed on the shaft 5 of the guide pole GP wear in a state of being in contact with each other. Although the height of the guide pole GP does not change due to the wear, the shaft 5 of the guide pole GP, which is pressurized by the pins 28 and 29 whose base ends are pressed by the screws 31, is As the wear of the screws 28 and 29 progresses, the screws 28 and 29 move toward the rotation shaft 23 of the drive gear 22 provided on the fixed portion side of the device.

As described above, the change in the standing position of the guide pole GP does not change the height of the guide pole GP.
Due to a change in the standing position of P, the winding angle of the magnetic tape T running around each part of the inclined pole SP and the guide pole GP in the direction in which the winding angle of the magnetic tape T with respect to the inclined pole SP is reduced. Thus, there is a problem that the running state of the magnetic tape may be hindered.

In the magnetic recording / reproducing apparatus illustrated in FIGS. 3 and 4 configured using the pole base assembly shown in FIG. 6, the magnetic recording / reproducing apparatus is provided on the pole base PB by the operation of the pressurizing mechanism PP. Male screw 27a formed on both slopes of the thread of female screw 8a and shaft 5 of guide pole GP.
The direction of change of the standing position of the guide pole GP, which is displaced by the abrasion of the two slopes of the thread while contacting each other, is determined by the inclination pole SP and the guide pole GP.
Is parallel to the running direction of the magnetic tape T running between the inclined pole SP and the inclined pole SP even if the standing position of the guide pole GP is changed due to the above-described cause. Since the winding angle of T does not change, the magnetic recording / reproducing apparatus shown in FIGS. 3 and 4 does not cause a problem that may occur in the magnetic recording / reproducing apparatus shown in FIGS. .

The control operation of the height of the guide pole GP in the pole base assembly shown in FIGS. 5 and 6 is performed within one rotation of the shaft 5 of the guide pole GP. The required amount of change in the height of the guide pole GP does not pose any problem because it is usually very small. If the pitch between the female screw 8a and the male screw 27a is increased, one of the shafts 5 of the guide pole GP is formed.
It goes without saying that the amount of change in the height of the guide pole GP performed within the rotation can be increased.

【The invention's effect】

As is apparent from the above description, the pole base assembly in the magnetic recording / reproducing apparatus of the present invention is provided outside the region where the external thread is formed on the outer peripheral surface of a part of the shaft of the guide pole. In two areas,
A spring plate fixed to the pole base with screws,
Slope of the thread of the internal thread provided on the pole base, such that the base end is pressed against each tip of each pin that is pressed in a direction perpendicular to the side surface of the shaft of the guide pole, The slope of the thread of the external thread formed on the shaft of the guide pole is in a state of being crimped to each other while both slopes of the thread of one screw are in contact with both slopes of the other thread. Therefore, even if the magnetic recording / reproducing apparatus is used for a long time and the slope of the thread of the internal thread provided on the pole base and the slope of the external thread formed on the shaft of the guide pole are worn, Is not displaced in its axial direction, so that the height of the guide pole does not change, and the shaft of the guide pole only displaces in a direction perpendicular to its axial direction, thus , The use of pole base assembly in the magnetic recording and reproducing apparatus of the present invention always done accurately the height control of the guide pole GP, will be also performed correctly bend correcting operation of the recording track of the magnetic tape. Also, both slopes of the thread of the internal thread provided on the pole base,
The inclination direction of the guide pole and the change direction of the guide pole standing position, which is displaced as both the slopes of the thread of the external thread formed on the shaft of the guide pole are worn while being in contact with each other, are determined by the inclination pole and the guide pole. By making the running direction of the magnetic tape parallel to the running direction, even if the standing position of the guide pole changes due to the wear of the screw, the winding angle of the magnetic tape with respect to the inclined pole is changed. Since there is no change, the running state of the magnetic tape can be stabilized.

[Brief description of the drawings]

FIG. 1 is a perspective view of a part of a magnetic recording and reproducing apparatus during a loading operation.

FIG. 2 shows a state in which a loading operation is completed.
FIG. 2 is a perspective view of a part of the magnetic recording / reproducing apparatus shown in FIG.

FIG. 3 is a perspective view of a part of the magnetic recording / reproducing apparatus during a loading operation.

FIG. 4 shows a state where the loading operation is completed.
FIG. 2 is a perspective view of a part of the magnetic recording / reproducing apparatus shown in FIG.

FIG. 5 is a view showing a pole base assembly.

FIG. 6 is a view showing a pole base assembly.

FIG. 7 is a diagram for explaining a threaded engagement state for explaining a problem.

FIG. 8 is a diagram for explaining a conventional example of a guide pole provided on a pole base.

FIG. 9 is a diagram for explaining the operation of the position sensor.

[Explanation of symbols]

DB: drum base, Dd: lower drum, Du: upper drum, H: rotary magnetic head, BC: base catcher,
DA: drum structure, PB: pole base, Md: drum drive] motor, Mg: motor, GP: guide pole, S
P: inclined pole, T: magnetic tape, RE: rotary encoder, PS: position sensor, PP: pressurizing mechanism, 5: shaft of guide pole, 7, lower flange, 7g: driven gear, 8a: female screw, 18, 19, 20, 46 ... gears,
10: elastic body, 11: upper flange, 12: roller, 13
, A light-shielding plate, 15 a rotating shaft of a motor Mg, 16 a light-shielding blade plate forming a part of the rotary encoder RE, 2
4: photo interrupter, 22: drive gear, 27a: male screw,

Claims (5)

[Claims] 1. A magnetic recording / reproducing apparatus, which is wound around a part of a drum peripheral surface by a rotary magnetic head provided so that a rotational trajectory surface is formed at a predetermined position with respect to a fixed portion of a body of a magnetic recording / reproducing apparatus. The recording and reproducing operations for the magnetic tape are performed, and the magnetic tape to be wound around a part of the drum peripheral surface is individually moved along the running path between the winding start side and the winding end side around the drum peripheral surface. The height of the disposed first and second guide poles is determined by the information on the curvature of the recording trace at a position close to the first guide pole obtained based on the reproduction signal from the magnetic tape and the second A closed loop automatic control operation for adjusting the recording trace of the magnetic tape to the rotation locus of the rotating magnetic head by changing the height control signal generated by using the bending information of the recording trace at a position near the guide pole of the rotating magnetic head. Do Means for generating information on the height of the guide pole, a drive source provided on a fixed portion of the body of the magnetic recording / reproducing apparatus, and a drive source provided on the shaft of the drive source and the guide pole described above. A pole base set provided with a guide pole in a magnetic recording / reproducing apparatus having a height control mechanism including a power transmission mechanism in which a gear is used at least in part between the driven gear and a driven gear; A pole base assembly in a magnetic recording / reproducing apparatus which is three-dimensional and includes means for applying a precompressed pressure in a direction perpendicular to the side surface of the axis of the guide pole. 2. A magnetic recording / reproducing apparatus, which is wound around a part of a drum peripheral surface by a rotary magnetic head provided so that a rotational trajectory surface is formed at a predetermined position with respect to a fixed portion of a body of a magnetic recording / reproducing apparatus. The recording and reproducing operations for the magnetic tape are performed, and the magnetic tape to be wound around a part of the drum peripheral surface is individually moved along the running path between the winding start side and the winding end side around the drum peripheral surface. The height of the first and second guide poles among the first and second inclined poles and the first and second guide poles arranged is obtained based on a reproduction signal from a magnetic tape. In addition, it is changed by a height control signal generated using the recording information bending information at a position near the first guide pole and the recording information bending information at a position near the second guide pole. The rotation of the rotary magnetic head described above Means for generating information regarding the height of the guide pole so that a closed loop automatic control operation for aligning the recording trace of the magnetic tape with the rolling locus is performed, and a drive source provided on a fixed portion of the body of the magnetic recording / reproducing apparatus And a height control mechanism including a power transmission mechanism in which a gear is used at least in part between the drive source and a driven gear provided on the shaft of the guide pole. A pole base assembly provided with a guide pole in the magnetic recording / reproducing apparatus, wherein the side face is parallel to the running direction of the magnetic tape between the inclined pole and the guide pole, and the axis of the guide pole. A pole base assembly in a magnetic recording / reproducing apparatus, further comprising means for applying a vertical preload. 3. A movable member capable of vertically abutting against side surfaces of both ends of a screw portion on a shaft of a guide pole, and a member pressing each of the movable members in a side direction of the screw portion. 3. The pole base assembly in the magnetic recording / reproducing apparatus according to claim 1, wherein a vertical pressurization is applied to the side surface of the axis of the guide pole. 4. A pole base assembly in a magnetic recording / reproducing apparatus according to claim 3, wherein a leaf spring is used as a member for pressing the movable member in the side direction of the screw portion. 5. A vertical pressurization is applied to side surfaces of both ends of a threaded portion of a shaft of the guide pole corresponding to a range where the magnetic tape is wound on a peripheral surface of the guide pole. A pole base assembly in the magnetic recording / reproducing apparatus according to any one of claims 1 to 4.