JPH052724A - Rotary head drum device - Google Patents

Abstract

PURPOSE:To prevent the abrasion of the contact terminal of a ground board, and reduce the torque loss at the time of the rotation of a rotary drum. CONSTITUTION:This device is equipped with a fixed drum 10 in which a shaft 11 is vertically stood and fixed, a bearing housing 20 supported through a pair of ball bearings and by the shaft 11 so as to be rotatable, a rotary drum 30 in which a head 32 is protruded on an outer peripheral face 30a, and which is screwed up and fixed to an upper flange 22 of the bearing housing 20 with a set screw 33, and motor 40 constituted of a rotor 41 screwed up and fixed to a lower flange 22 of the bearing housing 20 with a set screw 45, and a stater 46 fixed to the fixed drum 10, and faced with the rotor 41. Then, the base part of a ground plate 37 is screwed up and fixed to an upper face 31c of a bottom part 31 of the rotary drum 30 with the set screw 33. A contact terminal 37a is protruded at the lower face of the top end of the ground plate 37, and the contact terminal 37a is allowed to come in touch with a top face 11a of the shaft 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a helical scan type small rotary head drum device having a built-in motor.

[0002]

2. Description of the Related Art In a VTR (video tape recorder) as a magnetic recording / reproducing apparatus, a rotary drum having a head for recording / reproducing a video signal is arranged at a slight inclination from the tape running direction, and is rotated on the tape. A helical scan type rotary head drum device for recording in an oblique pattern is used. This will be described in detail with reference to FIGS. 4 and 5. Reference numeral 100 denotes a helical scan type rotary head drum device having a magnetic recording / reproducing capability of 8 mmV.
It is used for TR. The rotary head drum device 100 includes a rotary drum (upper drum) 110 having a head 111 protruding from an outer peripheral surface 110a, and the rotary drum 1
A fixed drum (lower drum) 120 that rotatably supports 10 through a pair of ball bearings (bearings) 122 and 123 fitted to a cylindrical fixed shaft 121 and a bearing housing 112, and the rotary drum 110. A motor 131 including a rotor 131 fixed to the upper surface side and a stator (substrate) 135 fixed to the upper end of the fixed shaft 121 and facing the rotor 131 with a predetermined clearance, and a head 111 rotating at the time of recording. A rotary transformer 140 composed of rotary rotors 141 and 142 on the rotor side fixed to the rotary drum 110 and on the stator side fixed to the fixed drum 120, which supplies a video signal to the rotary drum 110 and takes out a reproduced signal during reproduction. Has been done.

The rotary drum 110 is formed in a cylindrical shape having a bottom, and the pair of ball bearings 122, 12 are provided.
3. A substantially cylindrical bearing housing 11 fitted to the outer peripheral surface of
A pair of setscrews 113, 1 on the lower flange 112a of the second
The fixed shaft 121 by fastening and fixing via 13
It is rotatable with respect to. Further, the opening concave portion 1 formed on the lower surface side of the bottom portion 110b of the rotating drum 110.
10c is provided with a head screw 116 via a set screw 115.
Is fixed. The head 111 is fixed to the head base 116 with an adhesive or the like. The head base 116 is deformable downward by pressing a pairing adjusting push screw 117 so that pairing adjustment (head height adjustment) can be performed. The head 111 and the rotor-side rotary transformer 141 are connected via the elastically deformable U-shaped spring plate-shaped contactor 119 of the terminal plate 118 mounted around the lower flange 112a of the bearing housing 112. It is electrically connected.

The rotor 131 of the motor 130 is formed in a dish shape, and is fixed to the upper surface of the bottom portion 110b of the rotary drum 110 by a pair of set screws 133 and 133. An annular plate-shaped magnet 132 is mounted on the rotor 131.
Is fixed. In addition, the stator 1 of the motor 130
35 is fixed to an annular plate-shaped flange 137 fixed to the upper end of the fixed shaft 121 via a set screw 138.
The plural-phase coil portions 136 provided on the lower surface side of the stator 135 face the magnet 132 of the rotor 131 with a predetermined clearance. In FIG. 4, reference numeral 134 is a back yoke fitted and fixed in the upper end of the rotary drum 110, and 139 is a terminal plate, which is the set screw 138.
Is fixed to the center of the upper surface of the stator 135. A flexible board 150 for external connection of the stator 135 is attached to the terminal plate 139 via a guide protector 151.

Further, as shown in FIGS. 4 and 5, a mounting plate 160 is provided on the inner peripheral side of the upper surface of the rotor 131 of the motor 130 via a set screw 162 screwed into the bottom portion 110b of the rotary drum 110. It is fastened and fixed. This mounting plate 1
The ground spring 1 is attached to the pin 161 which is planted in the 60 and stands up.
The base end side of 65 is wound and supported. The rod-shaped contact terminal 166 fixed to the tip 165a of the earth spring 165 is pressed against the groove 137a having a substantially U-shaped cross section formed on the outer peripheral surface of the flange 137, so that the charge accumulated on the rotating drum 110 side is discharged. The electric power is discharged to the fixed drum 120 side via the fixed shaft 121.

The fixed drum 120 is formed in a cylindrical shape having a bottom, and a tape lead 120a for guiding a magnetic tape (not shown) is formed on the outer peripheral surface thereof. The rotating transformer 142 on the stator side is adhered and fixed to the upper surface of the bottom portion 120b of the fixed drum 120. Further, a flexible substrate (not shown) for the rotary transformer signal line is fixed to the bottom surface of the bottom portion 120b of the fixed drum 120 via a plurality of pins 124 and a terminal plate 125. still,
The fixed shaft 121 is the bottom portion 120 of the fixed drum 120.
The hole 120c formed in the center of b is fixed by press fitting so as to stand vertically.

[0007]

However, in the grounding structure using the grounding spring 165 or the like of the conventional rotary head drum device 100, the contact terminal 1 fixed to the tip 165a of the grounding spring 165 rotating with the rotating drum 110.
66 is a flange 137 which is always fixed to the fixed shaft 121.
Since it slides in a state of pressure contact with the groove 137a of the flange 137, the groove 137a of the flange 137 and the earth spring 16
5, the relative speed of the contact terminal 166 of No. 5 becomes large, the contact terminal 166 is easily worn, and the rotary drum 110
There was a drawback that the loss torque increased when rotating.

Therefore, the present invention provides a rotary head drum device capable of preventing wear of the contact terminal of the ground member and reducing loss torque during rotation of the rotary drum.

[0009]

A fixed drum having a shaft vertically erected and fixed, a bearing housing rotatably supported by the shaft via a bearing, and an upper portion of the bearing housing with a head protruding from an outer peripheral surface. A rotary drum fixed to the bearing housing, a rotor fixed to the lower part of the bearing housing, and a motor fixed to the fixed drum and composed of a stator facing the rotor, and a base of the ground member on the upper surface of the rotary drum. It is fixed and the contact terminal provided on the tip side of this ground member is freely contactable with the top surface of the shaft.

[0010]

The contact terminal provided at the tip of the earth member comes into contact with the top surface, which is a portion where the relative movement of the shaft fixed to the fixed drum that rotatably supports the rotating drum via the bearing and the bearing housing is small. With this configuration, wear of the contact terminal of the ground member is prevented, and the loss torque is reduced when the rotary drum rotates.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a helical scan type rotary head drum device, which is used for an 8 mm VTR as a magnetic recording / reproducing device. The rotary head drum device 1 includes a fixed drum (lower drum) 10 in which a cylindrical fixed shaft 11 is vertically fixed by press fitting into a hole 10b formed in the center of a bottom portion 10a, and the fixed shaft 11 described above. A pair of ball bearings 28,
A cylindrical bearing housing 20 rotatably supported via 28, a rotary drum (upper drum) 30 fixed to an upper portion of the bearing housing 20 by protruding a head 32 from an outer peripheral surface 30a by a predetermined amount, and The rotor 41 fixed to the lower part of the bearing housing 20 and the fixed drum 10
Fixed to the magnet 43 of the rotor 41 and the back yoke 44, each having a predetermined clearance (each 0.3
a coreless motor 40 composed of a stator 46 facing each other and a head 32 rotating during recording.
From the transformers 51 and 52 on the rotor side mounted on the lower surface side of the bearing housing 20 and on the stator side mounted on the upper surface side of the bottom portion 10a of the fixed drum 10 for supplying a video signal to the reproduction unit and reproducing the reproduction signal during reproduction. And the rotary transformer 50.

The fixed drum 10 is formed in a cylindrical shape having a bottom, and a tape lead 10c for guiding a magnetic tape (not shown) is formed on the outer peripheral surface 10d thereof. The rotating transformer 52 on the stator side is bonded and fixed to the upper surface of the bottom portion 10a of the fixed drum 10. Further, on the bottom surface of the bottom portion 10a of the fixed drum 10, a flexible substrate (not shown) for external connection of the rotary transformer 52 on the stator side is attached via a plurality of pins and a terminal plate.

As shown in FIGS. 1 and 2, upper and lower flanges 21 and 22 are integrally formed on the upper and lower portions of the bearing housing 20 so as to project therefrom. The upper flange 21 has a pair of substantially fan-shaped projecting portions, and female screw holes 23 for fastening and fixing the rotary drum 30 are formed at the centers of the respective projecting portions. The outer peripheral surface 20 a above the upper flange 21 is attached to the upper drum 21 by the rotary drum 30.
It is a centering reference plane that determines the radial position when mounting. A pair of insertion holes 24, 24 are formed in the upper flange 21 so as to sandwich the female screw holes 23. The lower flange 22 is formed in a disk shape so as to integrally project, and a pair of female screw holes 25, 25 for fastening and fixing the rotor 41 are formed at positions 90 ° apart from the positions of the female screw holes 23. There is. An outer peripheral surface 22a of the lower flange 22 serves as a centering reference surface that determines a radial position of the rotor 41 when the rotor 41 is mounted on the lower flange 22. Also, this lower flange 22
3 through holes 26 are formed between the pair of female screw holes 25, 25, respectively, and each notch 27 is formed on the lower side thereof.
Has been formed. A compression coil spring 29 is interposed between the pair of ball bearings 28, 28 fitted in the bearing housing 20, and the pair of ball bearings 28, 28 is loose relative to the fixed shaft 11. There is no such thing.

The rotary drum 30 is formed in a cylindrical shape having a bottom, and the upper flange of the bearing housing 20 is fitted with respective setscrews 33 screwed into the female screw holes 23 of the upper flange 21. It is fastened and fixed to 21. The base portion of the head base 35 is fixed to the opening recess 31b formed on the lower surface 31a side of the bottom portion 31 of the rotating upper drum 30 via the set screw 34. The head 32 is fixed to the tip end side of the upper surface of the head base 35 with an adhesive or the like. The tip side of the head base 35 is deformable downward by pressing a tip 36a of a push screw (pair rig adjusting screw) 36 that is screwed into a female screw hole 31d formed in the bottom portion 31 so that pairing adjustment (head The height can be adjusted. Further, the base portion of a substantially rectangular earth plate (earth member) 37 is fastened and fixed to the upper surface 31c of the bottom portion 31 of the rotary drum 30 by the one set screw 33. The earth plate 37 is the top surface 11 of the fixed shaft 11.
A hemispherical contact terminal 37a is integrally projectingly formed at the center of the lower surface of the tip of the contact terminal 37a. This contact terminal 3
7a is constantly urged by the elastic force of the earth plate 37 so as to make point contact with the top surface 11a.

The rotor 41 of the motor 40 comprises a dish-shaped rotor case 42, an annular plate-shaped McNet 43 fixed to the upper surface of the rotor case 42, and a disk-shaped back yoke 44. It is fastened and fixed to each female screw hole 25 of the lower flange 22 of the bearing housing 20 via a set screw 45. As shown in FIGS. 2 and 3, a mounting hole 42a through which the upper flange 21 of the bearing housing 20 is inserted is formed in the center of the rotor case 42, and an annular recess 42b is formed on the bottom surface thereof. is there.
The peripheral surface 42c of the recess 42b is the bearing housing 20.
The lower flange 22 is a reference surface fitted to the centering reference surface 22a, and, as shown in FIG. 3, a pair of lower surfaces 42d, 42d protruding inwardly are mounting surfaces. A hole portion 42d 'through which the shank portion of each set screw 45 is inserted is formed on each mounting surface 42d. Each of the mounting surfaces 42d is a surface that comes into contact with the upper surface of the lower flange 22, and is 50 degrees from the lower surface of the other recess 42b.
There is a height difference of about μm.

The back yoke 44 of the rotor 41 is provided with a pair of back yoke supports 49, 49 provided 180 ° apart on the outer peripheral surface 20b between the upper and lower flanges 21, 22 of the bearing housing 20. Bearing housing 20 so that the gap does not change with reference to 20b.
Installed on. The back yoke 44 is made of a damping material having a three-layer structure in which resin is sandwiched between metal plates. Also,
The back yoke support 49 is made of polyester elastomer resin, rubber or the like having a high vibration damping effect.

The stator 46 of the motor 40 is composed of a disk-shaped stator substrate 47 and a plurality of layers of coil portions 48 and the like provided on the lower surface of the stator substrate 47. It is adhered and fixed to the step portion 10e formed in the middle of the inner peripheral surface of the peripheral wall portion of the fixed drum 10 with an adhesive. The multi-phase coil portion 48 of the stator 45 is connected to the magnet 4 of the rotor 41.
No. 2 has a predetermined clearance (about 0.3 mm) and faces each other.

The rotor side rotary transformer 51 is adhered and fixed to the lower surface of the lower flange 22 of the bearing housing 20 with an adhesive or the like, and is fixed to the upper surface of the bottom portion 10a of the fixed drum 10 on the stator side. It faces the rotary transformer 52 with a predetermined gap (for example, 25 μm). In addition, the wiring (not shown) of the rotary drain 51 on the rotor side is provided on the bottom portion 31 of the rotary drum 30 through the notches 27 and the insertion holes 26 of the lower flange 22 of the bearing housing 20 and the insertion holes 24 of the upper flange 21. Upper surface 31
A head 32 that is connected to a relay board (not shown) and can record and reproduce on a head base 35 via this relay board.
It is connected to the.

According to the rotary head drum device 1 of the above embodiment, the fixed shaft 11 vertically erected and fixed to the fixed drum 10 is provided.
The bearing housing 20 is rotatably supported by a pair of ball bearings 28, 28 on the bearing housing 2.
No. 0 is fixed to the upper flange 21 of the rotary drum 30, and the lower flange 22 is fixed to the rotor 4 of the motor 40.
1 is fastened and fixed so that the head 32 is projected to the outer peripheral surface 30a of the rotary drum 30 by a predetermined amount.
Is fastened and fixed to the lower surface side of the head base 35 via a head base 35, and the head side of the head base 35 is freely deformable by pressing with a tip 36a of a push screw 36 screwed from the upper surface 31c side of the bottom portion 31 of the rotary drum 30. Because it is configured, push screw 3
Unlike the conventional case, other members such as the rotor of the motor do not come above 6 and the pairing adjustment can be easily performed in the completed state of the rotary head drum device 1.

Thus, the rotor 41 of the motor 40 is
Since the rotor case 42 and the like are fastened and fixed to the lower flange 22 of the bearing housing 20 by the set screw 45 and cannot be directly attached to the rotary drum 30 side, when the rotor 41 of the motor 40 is fastened and fixed, the rotary drum 30 is not bent. It does not occur and the pairing is not misaligned.

Further, since the outer peripheral portion 47a of the stator substrate 47 of the stator 46 of the motor 40 is fixed to the step portion 10e of the fixed drum 10 with an adhesive or the like, the rigidity of the stator 46 is increased and the rotor 41 of the motor 40 is fixed. The vibration of the stator 46 due to the rotation can be damped. Further, the back yoke 44 that rotates together with the rotor case 42 is formed of a vibration damping material in which a resin plate is sandwiched between steel plates, and the back yoke support 49 that supports the back yoke 44 is made of a material having a high vibration damping property such as polyester elastomer. Since it is formed of, the vibration of the back yoke 44 can be damped. As a result, when the motor 40 is rotated, vibrations of the stator 46 and the back yoke 44 can be suppressed as compared with the conventional one, and electromagnetic noise of the motor 40 due to these vibrations can be reliably suppressed.

Further, considering the procedure for assembling the rotary head drum device 1, at the stage before mounting the rotary drum 30,
Since the motor 40 can rotate, the balance can be adjusted in a state where the motor 40 is incorporated in the bearing housing 20. Next, after the rotary drum 30 is attached (after the drum is completed), the bottom portion of the rotary drum 30 is installed. By adding a weight or the like on the upper surface 31c of 31, the dynamic balance adjustment in the final completed state can be performed, and the rotary head drum device 1 with high accuracy can be provided.

By adopting such a structure of the bearing housing 20 and the motor 40, as shown in FIG. 2, when the motor 40 or the like is assembled, the rotor 41 of the rotor 41 does not hit the upper flange 21 of the bearing housing 20. It can be attached to the lower flange 22 through the case 42, and the upper flange 21 and the magnet 43 can be attached.
Can be made large. Further, when the rotor case 42 of the rotor 41 is mounted on the lower flange 22 of the bearing housing 20, the outer peripheral surface 22 of the lower flange 22 is attached.
Since the concave portion 42b formed on the lower surface side of the rotor case 42 is fitted into the rotor case 42 by using a as the centering reference surface, the rotor case 42 can be assembled at low cost and with high accuracy.

Furthermore, the rotary transformer 51 on the rotor side
Wirings (not shown) extending from the notches 27 formed in the lower flange 22 of the bearing housing 20 and the insertion holes 26 and the insertion holes 2 formed in the upper flange 21 are provided.
4 can be easily routed to the upper surface 31c side of the bottom portion 31 of the rotary drum 30. In addition, the rotary transformer 51
A relay board (not shown) for connecting the head 32 to the head 32 via the wiring is an upper surface 31 of the bottom 31 of the rotary drum 30.
Since it can be disposed on the c side and does not need to be lifted up and mounted by a guide protector unlike the conventional case, the overall height of the rotary head drum device 1 can be suppressed to a lower value, and the overall thickness of the device can be reduced. Further reduction in size and weight can be achieved.

Further, as described above, since other members such as a guide protector do not come to the upper surface 31c of the bottom portion 31 of the rotary drum 30 and the top surface 11a of the fixed shaft 11 unlike the conventional case, the ground plate 37 of the ground plate 37 is not provided. Connect the contact terminal 37a to the fixed shaft 1
It is possible to make a point contact with the center of the top surface 11a of No. 1. This ground plate 37 is used for the bearing housing 2 of the rotary drum 30.
One set screw 3 fastened and fixed to the upper flange 21 of No. 0
3 allows easy attachment to the upper surface 31c of the bottom 31 of the rotary drum 30 at low cost. This rotating drum 30
Although the shaft 11 for rotating the shaft is of a fixed type, the ground plate 37 is provided at the center of the top surface 11a of the fixed shaft 11 where the relative speed of the contact portion is small, as in the case of the rotary type. The contact terminal 37a can be point-contacted. Therefore, when the rotary drum 30 rotates at high speed, the contact terminals 37a of the ground plate 37 are worn and the ground plate 3
The torque loss of the rotary drum 30 due to the contact of 7 can be suppressed as much as possible. Thereby, the earth plate 37
As a result, the electric charge that tends to stay on the rotary drum 30 side can be surely discharged to the fixed drum 10 side via the fixed shaft 11, and the electric charge is not accumulated on the rotary drum 30 and the head 32. Etc. will not occur.

According to the above-mentioned embodiment, the rotary drum is formed in a cylindrical shape with a bottom, but the rotary drum is formed in a substantially dish shape, a disk shape, or the like to further reduce the overall thickness of the rotary head drum device. You can

[0028]

As described above, according to the rotary head drum device of the present invention, the shaft fixed to the fixed drum that rotatably supports the rotary drum through the bearing and the bearing housing has a small relative motion. Since the contact terminal provided on the tip of the earth member is configured to be freely contactable with a certain top surface,
It is possible to prevent wear of the contact terminal of the earth member and reduce loss torque when the rotary drum rotates.

[Brief description of drawings]

FIG. 1 is a sectional view of a rotary head drum device showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a relationship between a rotor and a bearing housing of a motor used in the rotary head drum device.

FIG. 3 is a perspective view of the rotor seen from the back side.

FIG. 4 is a cross-sectional view of a conventional rotary head drum device.

FIG. 5 is a plan view of a rotary drum of the conventional rotary head drum device.

[Explanation of symbols]

1 ... Rotary head drum device, 10 ... Fixed drum, 11 ...
Shaft, 20 ... Bearing housing, 28 ... Ball bearing, 30 ... Rotating drum, 30a ... Outer peripheral surface, 32 ...
Head, 37 ... Ground plate (ground member), 37a ... Contact terminal, 40 ... Motor, 41 ... Rotor, 46 ... Stator.

Claims (1)

Claim: What is claimed is: 1. A fixed drum having a shaft vertically erected and fixed,
A bearing housing rotatably supported on the shaft via bearings, a rotating drum fixed to the upper portion of the bearing housing with a head protruding from the outer peripheral surface, a rotor fixed to the lower portion of the bearing housing, and A motor comprising a stator fixed to a fixed drum and facing the rotor, a base of an earth member is fixed to an upper surface of the rotary drum, and a contact terminal provided on a tip side of the earth member is connected to a top of the shaft. A rotary head drum device characterized by being able to contact the surface freely.