JPH04210759A - Capstan motor for recording/reproducing apparatus - Google Patents

Abstract

PURPOSE:To improve wow flutter value by making a plurality of elongated holes or holes in a rotor section with same pitch and securing to a shaft holding section with screws at an arbitrary angular position through the holes. CONSTITUTION:A rotor section 7 is provided with elongated holes 5 at three points with same pitch and fastened to a rotor fixing base 15 at a shaft holding section 24 by means of screws 6. When the fixing phase is shifted between the shaft holding section 24 and the rotor section 7, the screw is loosened and the phase between a shaft 15 and an FG magnet 3 can be shifted within the range of the elongated holes 5 at three points. Furthermore, since the elongated holes 5 are arranged at same pitch, the phase can be shifted by 120 deg. if the elongated holes or holes are provided at three points. The reason of providing a plurality of holes is to make possible to fasten the shaft holding section 24 and the rotor section through the screws 6 and to shift the fixing phase considerably and fine adjustment can be realized through the elongated holes. According to the constitution, the rotor section can be secured, through screws, at a position exhibiting best characteristic while measuring wow flutter characteristic.

Description

[Detailed description of the invention]

[00011

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capstan motor for a recording/reproducing apparatus, and more particularly to a capstan motor having a structure designed to reduce wow and flutter. [0002] [0002] In a recording/reproducing device, a capstan motor has two unit parts, a stator part and a rotor part.
It consists of parts such as a housing that holds the shaft, a bearing, and a preload member. The capstan motor of a conventional recording/reproducing device will be explained below. Figure 2 shows a conventional capstan motor, with (A) showing a cross-sectional view and (B) showing a bottom view. In (A), the rotor part 31 is
rotapos 26, back yoke 27, FG magnet 2
8. Composed of motor magnet 29, shaft 3
0 is fixed to the rotor post 26 by press fitting, shrink fitting, adhesive, etc. FG magnet 28 is back yoke 27
The motor magnet 29 is attached to the back yoke 27 by adhesive or the like. The stator section 38 is composed of a coil 32, a magnetic sensor 33, a circuit board 34, and a magnetic sensor 35 for FG.The coil 32 is bonded, the magnetic sensor 33 is soldered, and the magnetic sensor 35 is bonded with screws 36. Each is attached to a circuit board 34. Other parts include a housing 39, a bearing 40, a preload member 41, a spring 42, and a preload fixing member 43.
Further, the stator portion 38 is attached to the chassis 46 with screws 37. The shaft 30 is rotatably supported by lower and upper bearings 40, and a preload member 41, a spring 42, and a preload fixing member 43 apply an appropriate preload to the bearing 40. The operation of the capstan motor of the recording/reproducing apparatus configured as above will be explained below. The capstan motor is driven by detecting the phase of the magnetic flux of the motor magnet 29 with a magnetic sensor 33, while switching the timing of the current flowing through the coil 32, and by detecting the phase of the magnetic flux of the motor magnet 29.
8 magnetic flux (FG multiplied signal is detected by the FG magnetic sensor 35 and fed back to the control circuit to rotate the capstan motor at a constant speed, and has already been made into a film. [0003]

[Problems to be Solved by the Invention] However, in the above configuration, the shaft 30 as the rotor portion 31 is press-fitted into the rotor post 26, and the shaft 30 and the FG magnet 2
The relative angular position with respect to 8 is fixed. This causes the following inconvenience. One of the indicators of audio performance in a video tape recorder (VTR) is the wow and flutter value, which refers to deviations in audio output due to variations in tape speed. The mechanical influence of the capstan motor is a major factor that causes fluctuations in tape speed.
It is no exaggeration to say that in broadcast VTRs, where the wow and flutter value standards are extremely strict, the performance of the capstan motor determines the wow and flutter value. [0004] Two major factors that cause tap speed fluctuations are the eccentric component of the shaft of the capstan motor and the rotational unevenness of the capstan motor whose rotation is controlled by the FG multiplier signal, that is, the FG accuracy component. It occupies a large proportion. The eccentric component of the shaft includes accuracy such as roundness of 2 cylindrical degrees and other assembly accuracy with bearings and housings, and the eccentricity is limited to 1 micron (p-p). This 1 micron eccentric component alone considerably worsens the wow and flutter value. Furthermore, it is inevitable that there will be at least a slight amount of unevenness in the FG accuracy component. [0005] The total component of these two components causes a fluctuation in the tape speed, but depending on the relative angular position of the shaft and the FG magnet, this total component may be large due to the addition of both, or vice versa. may cancel each other out and be subtracted, resulting in a smaller total component. In a conventional capstan motor configuration in which the relative angular positions of the shaft and the FG magnet are randomly combined and both are firmly fixed, variations in the wow and flutter values due to the above-mentioned variations in the total component are an unavoidable problem. [0006] The present invention solves the above-mentioned problems, and provides a cap that allows the installation angle of the shaft (shaft holding part) and FG magnet (rotor part) to be adjusted arbitrarily, thereby improving the wow and flutter value. The purpose is to provide stun motors. [0007]

[Means for Solving the Problems] In order to achieve the above object, the capstan motor of the recording/reproducing device of the present invention has a plurality of elongated holes or six holes arranged at equal pitches in the rotor portion. It can be screwed and fixed to the shaft holder at any angular position via the . [0008]

[Operation] With the above structure, the capstan motor of the present invention allows the installation angle of the shaft holding part and the rotor part to be adjusted arbitrarily by loosening the screws, and by tightening the screws at the optimal angular position. Eccentric component and F
Wow and flutter can be reduced by shifting the phase of the G precision component to reduce the total component of both. [0009]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. [00101 Figure 1 shows the capstan motor of the present invention (
A) is a sectional view, and (B) is a bottom view thereof. (A)
The rotor section 7 is composed of a rotor post 1, a back yoke 2, an FG magnet 3, and a motor magnet 4. The motor magnet 4 is integrated with the back yoke 2 by outsert molding, caulking, etc.
installed on. [0011] The stator unit 14 is composed of a coil 8, a magnetic sensor 9, a circuit board 10, and a magnetic sensor 11 for FG. circuit board 10 respectively.
installed on. [0012] The shaft holding part 24 is composed of a rotor mounting base 16, a shaft 15, a housing 17, a bearing 18, a preload member 19, a spring 20, and a preload fixing member 21, and the bearing 18 is held at the upper and lower parts of the housing 17. The rotor is attached to one end of the shaft 16 by fixing the base 15 by shrink fitting, gluing, press fitting, screwing, etc.
At the other end of the shaft 16 there are lower and upper bearings 18, a preload member 19, a spring 20, a preload fixing member 21, and the upper and lower bearings 18 are given optimal preload by springs 20. [0013] As described above, the capstan motor of this embodiment includes the rotor section 7, the stator section 14, and the shaft holding section 24.
The stator part 14 is connected to the chassis 25 by screws 13, the shaft holding part 24 is connected to the chassis 25 by screws 23, and the rotor part 7 is connected to the rotor by a plurality of elongated holes 5 arranged at equal pitches. It is attached to the base 15 with screws 6. The reason why the hole is an elongated hole is so that the angle of attachment of the rotor portion 7 to the base 15 can be adjusted, so the elongated hole 15 may be a round hole with plenty of room. [00141] The operation of the capstan motor of this embodiment configured as above will be explained. The rotor part 7 has three elongated holes 5 arranged at equal pitches, and the rotor attachment of the shaft holding part 24 is fastened to the base 15 with screws 6, and the attachment of the shaft holding part 24 and the rotor part 7 is When shifting the phase, it is possible to loosen the screw 6 and shift the phase of the shaft 15 and the FG magnet 3 within the range of the three long holes 5. Also, since the long holes 5 are provided at equal pitches, it is possible to shift the phase between the shaft 15 and the FG magnet 3 within the range of the three long holes 5. If there are holes or holes in three locations, it is also possible to deviate the phase for 120° installation. The reason for providing a plurality of long and large parts is that the shaft holding part 24 and the rotor part 7 are connected by screws 6.
This is because they are fastened together, and because the mounting of both allows for a large phase shift, and the elongated hole allows for fine adjustment. [0015] Note that the gist of the present invention can be achieved even in a configuration in which the rotor post 1 of the rotor portion 7 and the shaft 15 are fastened laterally with screws (such as locking screws). in this case,
The installation phase of the rotor part 7 and shaft holding part 24 is 0°~
It can be adjusted in a range of 360 degrees, and the structure may be such that a thread is cut at the lower end of the shaft 15 and the rotor part 7 is fastened with a nut etc. As before, the rotor part 7 and the shaft holding part 24 are attached in phase. is adjustable in the range of 0° to 360°. [0016] In any case, while measuring the flatten characteristics, find the point where the characteristics are the best and fix the screws. [0017]

[Effects of the Invention] As is clear from the above explanation, in the capstan motor of the present invention, the phases of the attachment of the shaft holding part and the rotor part can be arbitrarily adjusted. With a configuration that allows the phase relationship to be shifted, the installation phase of the shaft and FG magnet is adjusted so that the total component of wow and flutter due to shaft eccentricity component and wow and flutter due to FG precision component is small, and the wow and flutter value is small. A capstan motor with less variation in characteristics can be provided, and its practical effects are high.

[Brief explanation of the drawing]

(Figure 11 (A) is a sectional view of Embodiment 1 of the capstan motor of the present invention (B) is a bottom view of the same)

[Figure 21 (A) is a sectional view of a conventional capstan motor (B) is a bottom view of the same [Explanation of symbols] 3 FG magnet 7 Rotor section 11 FG magnetic sensor 14 Stator section 15 Shaft 16 Rotor is mounted on base 18 Bearing

[Figure 1]

Claims (1)

[Claims] Claim 1: A rotor portion having an FG magnet, and an FG magnet.
The stator part has a magnetic sensor for FG that detects the magnetism of the magnet, a shaft rotatably supported by a bearing, and a rotor mounting base firmly fixed to the shaft, and the rotor part is mounted with screws. A capstan motor for a recording/playback device is fixed to the base, and the relative angular position of the two can be adjusted by loosening this screw.