JPH062959U - Drum motor - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the influence of magnetic noise generated by the stator core, drive magnet, etc. on the magnetic head. A shield plate for shielding magnetic noise between a lower portion of a rotary cylinder 1 to which a magnetic head 5 is fixed and an upper portion to which a rotor case 3 to which a drive magnet 2 is attached are fixed, for example, an inner peripheral surface. Fix 17

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a drum motor that prevents magnetic noise generated from a stator core, a drive magnet, or the like from affecting a magnetic head.

[0002]

[Prior art]

 A structure shown in FIG. 5 is known as a drum motor applied to a VTR or the like. A rotor case 3 attached with a drive magnet 2 is fixed to the upper part of a rotary cylinder 1 as an upper drum that is rotated by a rotary source by a screw 4, and a magnetic head 5 is fixed to the lower part of the rotary cylinder 1. . Further, a rotor 6A of a rotary transformer 6 is fixed to the lower portion of the rotary cylinder 1, and the rotor 6A and the magnetic head 5 are connected by a lead wire 7.

On the other hand, a stator 6B facing the rotor 6A of the rotary transformer 6 is fixed above the fixed cylinder 8 as a lower drum facing the rotary cylinder 1, and the fixed cylinder 8 is directly rotated by press fitting or the like. Not installed on the fixed shaft 10.

A stator core 11 is attached to a base plate 12 so as to face the drive magnet 2, and the base plate 12 is fixed to a support portion 14 fixed to a fixed shaft 10 by screws 13. A coil 15 is wound around the stay core 11. The rotary cylinder 1 is configured to be rotatable with respect to the fixed shaft 10 via a bearing 16.

[0005]

[Problems to be solved by the device]

 By the way, in the conventional drum motor, there is a problem that magnetic noise generated from the stator core, the drive magnet, and the like affects the magnetic head. Therefore, the recording / reproducing operation by the magnetic head cannot be performed normally.

The present invention has been made in consideration of the above problems, and an object of the present invention is to provide a drum motor capable of preventing the influence of magnetic noise on the magnetic head.

[0007]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a drum motor having a rotary cylinder having a rotor case having a drive magnet facing a stator core fixed to an upper part thereof and a magnetic head fixed to a lower part thereof. It is characterized in that a shield plate for blocking magnetic noise to the magnetic head is fixed in the middle between the upper part and the lower part.

[0008]

[Action]

 Since the shield plate is fixed between the lower part where the magnetic head of the rotating cylinder is fixed and the upper part where the drive magnet etc. are fixed, the magnetic noise generated at the upper part of the rotating cylinder is protected by the shield plate. Since it is cut off, the influence on the magnetic head is prevented.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a half sectional view showing an embodiment of a drum motor of the present invention. 1 is a rotary cylinder as an upper drum, 3 is a rotor case to which a drive magnet 2 is attached, It is fixed. 5 is a magnetic head fixed to the lower part of the rotary cylinder 1, 6 is a rotary transformer whose rotor 6A is fixed to the other lower part of the rotary cylinder 1, and 7 is a lead connecting the rotor 6A of the rotary transformer 6 and the magnetic head 5. It is a line. Reference numeral 8 denotes a fixed cylinder as a lower drum which is attached to the fixed shaft 10 by press fitting or the like, and a stator 6B facing the rotor 6A is fixed to the upper portion. A stator core 11 around which a coil 15 is wound is attached to a substrate 12, and the substrate 12 is fixed to a support portion 14 fixed to a fixed shaft 10 by a screw 13. Reference numeral 16 is a bearing that rotatably supports the rotary cylinder 1 with respect to the fixed shaft 10. The above configuration is the same as the conventional one.

Reference numeral 17 denotes a seal plate fixed to the inner peripheral surface of the rotary cylinder 1, which has a ring shape as shown in FIG. 2 or a cup shape as shown in FIG. 3 and is fixed by press-fitting, bonding or the like. There is. The shield plate 17 is fixed to the upper part of the rotary cylinder 1, and the magnetic noise generated from the drive magnet 2, the rotor case 3 to which the drive magnet 2 is attached, or the stator core 11 facing the drive magnet 2 is removed. The magnetic head 5 fixed to the lower part of 1 is blocked and acts so as not to affect.

Therefore, according to the present embodiment, the magnetic noise is blocked by the presence of the shield plate 17 fixed to the inner peripheral surface of the rotary cylinder 1, so that the influence on the magnetic head 5 is prevented. As a result, the recording and reproducing operations by the magnetic head 5 can be performed normally.

FIG. 4 shows another embodiment of the present invention, showing a tape drive system of the cylinder head 25 of the VTR and its peripheral portion. The magnetic tape 40 supplied from the supply reel 31 is guided to the cylinder head 25 via a back tension post 32, a full width erasing head 33, an impedance roller 34, a vertical guide, an inclined guide and the like. The magnetic tape 40 is wound around the cylinder head 25 obliquely within a predetermined angle range, passes through an inclined guide and a vertical guide, and further includes an impedance roller 35, a voice head 36 including a voice erasing head and a voice control head, a capstan 37, and It is adapted to be taken up by a take-up reel 39 via a pinch roller 38. The cylinder head 25 comprises a lower fixed cylinder 8 and an upper rotary cylinder 1, and the rotary cylinder 1 is rotationally driven by a drum motor as shown in FIG.

According to the present embodiment as described above, it is possible to prevent the influence of magnetic noise particularly on the voice head 36. Therefore, normal operation is performed during audio recording and reproduction.

The shield plate 17 used in the present embodiment can be fixed to the inner peripheral surface of the rotary cylinder 1 by a simple means such as press-fitting or adhesion without using any special means, which causes an increase in cost. Can achieve the purpose without.

[0015]

[Effect of device]

 As is clear from the above description, according to the present invention, the shield plate is provided between the lower portion of the rotary cylinder, to which the magnetic head is fixed, and the upper portion, to which the rotor case having the drive magnet facing the stator core is fixed. Since it is fixed, it is possible to prevent the influence of the magnetic noise generated in the upper part of the rotating cylinder on the magnetic head.

[Brief description of drawings]

FIG. 1 is a half sectional view showing an embodiment of a drum motor of the present invention.

FIG. 2 is a schematic view showing the shape of a shield plate used in the drum motor of this embodiment.

FIG. 3 is a schematic view showing another shape of the shield plate used in the drum motor of this embodiment.

FIG. 4 is a perspective view of a tape drive system according to another embodiment of the present invention.

FIG. 5 is a half sectional view showing a conventional drum motor.

[Explanation of symbols]

 1 rotating cylinder (upper drum) 2 drive magnet 3 rotor case 5 magnetic head 8 fixed cylinder (lower drum) 11 stator core 17 shield plate 36 voice head

Claims (1)

[Scope of utility model registration request] 1. A drum motor having a rotary cylinder, in which a rotor case having a drive magnet facing a stator core is fixed to the upper part and a magnetic head is fixed to the lower part, in an intermediate part between the upper part and the lower part of the rotary cylinder. A drum motor characterized in that a shield plate for blocking magnetic noise to the magnetic head is fixed to the.