JP2002051494A - Capstan motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capstan motor in which play in the thrust direction is adjusted with a bearing holder and a thrust cap. SOLUTION: This capstan motor is provided with a rotor 20, having a rotor yoke 16 in which a capstan shaft 19, is disposed upright at almost the central part, and a driving magnet 17 is installed in the outer periphery, a bearing holder 3 having bearings 14, 15 where a capstan shaft is inserted in upper and lower ends in the inside, and holding the capstan shaft rotatably and a stator 10 fixed to the bearing holder in which stator a coil 8 is wound around a core 7 having salient poles arranged at a prescribed gap from the driving magnet. A thrust cap 30 and a stop ring 24 are installed in the upper part of the bearing holder, screwing parts are installed in the bearing holder and the thrust cap and integral formation is obtained, and the gap adjustment of the rotor in the thrust direction is made by rotating the thrust cap.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capstan motor used for driving a magnetic tape or the like, and more particularly to a bearing holder structure used for a VTR capstan motor.

[0002]

2. Description of the Related Art For example, in a capstan motor of a VTR, bearings are fitted to upper and lower ends of an inner peripheral surface of a cylindrical bearing holder, and a capstan shaft of the motor is supported by these bearings. . FIG. 5 is a sectional view showing an example of the conventional capstan motor 1. As shown in FIG. FIG.
, The substrate 2 serving as a motor base has a hole 2
The bearing holder 3 is inserted into the hole 2a. Note that the above-described substrate 2 serving as a motor base
Is formed by superposing an iron plate 5 on a printed circuit board 4.
The bearing holder 3 is cylindrical and has flanges 3a, 3b on the central outer peripheral surface.
And the upper end surface of the flange portion 3a is in contact with the printed circuit board 4. A screw 6 is inserted into the flange 3a, and a tip 6a of the screw 6 penetrates a stator core 7 and a flange 3a, which will be described later, and is screwed into the printed circuit board 4 and the iron plate 5, so that the bearing holder 3 is formed. It is fixed to the iron plate 5.

[0003] A stator core 7 is arranged below the printed circuit board 4, and the stator core 7 is fixed to the iron plate 5 together with the flange 3a and the like as described above. Stator core 7
Is formed by laminating a plurality of magnetic plates, and has a plurality of salient poles on the outer periphery. A driving coil 8 is wound around each salient pole.
The stator 10 is configured by the stator core 7.

[0004] Reference numeral 11 denotes a Hall element for detecting a rotor position for determining a current flowing through the drive coil 8, 12 a magnet for frequency generation (hereinafter referred to as FG) on the rotor side, and 13 a magnet for the rotor.
An MR element for extracting a speed signal in cooperation with the FG magnet 12 described above.
Each of the R elements 13 is fixed to the printed circuit board 4 described above.

At the upper and lower ends of the inner peripheral surface of the bearing holder 3,
An upper bearing 14 and a lower bearing 15 made of a copper or iron-based sintered oil-impregnated bearing or the like serving as a radial bearing are mounted at predetermined intervals. The upper and lower bearings 14, 15
Are set wider in order to improve the rigidity of the capstan shaft 19 described later. In addition, it goes without saying that the above-mentioned capstan shaft 19 is inserted into the shaft holes of the upper and lower bearings 14 and 15.

On the other hand, inside the rotor yoke 16 whose outer peripheral portion is drawn, a ring-shaped drive magnet 17 which is multipolar magnetized corresponding to the outer peripheral portion of the stator core 7 is outsert molded or bonded and fixed on the outer periphery. The above-mentioned resin magnet is multi-polarized to form the FG magnet 12 described above. The aforementioned ring-shaped drive magnet 17 is
Needless to say, it faces the stator core 7 with a certain gap.

Further, a bush 18 is swaged substantially at the center of the rotor yoke 16 and a capstan shaft 19 is press-fitted at the center of the bush 18. A pulley 21 for external driving for loading, reel driving, and the like is attached to the outer periphery of the bush 18 below the center portion so as to center on the capstan shaft 19. A ring-shaped washer 22 made of resin is arranged between the bush 18 on which the capstan shaft 19 is press-fitted upright and the lower bearing 15 so that the lower end of the bush 18 directly contacts the lower bearing 15. Not configured. The ring-shaped drive magnet 17, the rotor yoke 16, the capstan shaft 1
9 and the like constitute the rotor 20.

On the other hand, an upper structure of the upper bearing 14 is provided with the following structure for preventing oil from adhering to the capstan shaft 19 and preventing the rotor 20 from coming off. That is, on the upper part of the upper bearing 14, an oil leakage preventing washer 23 for preventing oil leakage, a resin stop ring 24 for preventing the rotor 20 from coming off, and a thrust cap 25 are attached to the outer periphery of the bearing holder 3 with an adhesive. It is fixed at.

The resin stop ring 24 constitutes a thrust bearing means which supports the capstan shaft 19 and the rotor 20 which are the rotating shafts in the thrust direction as described above and also serves to prevent detachment.

By controlling the energization of the driving coil 8 wound around the salient poles of the stator core 7 configured as described above,
A ring-shaped drive magnet 17 is urged, and a rotor yoke 16 to which the ring-shaped drive magnet 17 is fixed, a bush 18 caulked by the rotor yoke 16, and a capstan shaft 19 which is a rotary shaft press-fitted into the bush 18 are provided. It is driven to rotate.

[0011]

By the way, the rotor 20
The thrust cap 25 and the stop ring 24 are usually rotated by their own weight and are rotated in contact with each other. As described above, the resin-made ring-shaped washer 22 is disposed so that the bush 18 and the lower end of the lower bearing 15 do not come into direct contact with each other. A gap (play) G occurs in the thrust direction between the ring washer 22 and the ring washer 22.

In particular, in the case of a VTR deck mounted on a vehicle or the like, the rotor 20 moves up and down by the play in the thrust direction due to vibration and inclination. If the play of the rotor 20 in the thrust direction with respect to the stator core 7 is larger than an allowable range, the tape during recording and playback may be damaged,
The magnetic position relationship between the ring-shaped drive magnet 17 and the stator core 7 fluctuates or shifts, and the characteristics of the motor change, so that predetermined performance cannot be obtained. For this reason,
There is a problem that parts and assembling precision for minimizing backlash in the thrust direction must be increased, and the cost becomes extremely high. An object of the present invention is to provide a capstan motor in which a play is adjusted in a thrust direction by a bearing holder and a thrust cap in order to solve such a problem.

[0013]

According to the present invention, in order to achieve the above object, a capstan shaft 19 is provided substantially at the center.
The capstan shaft 19 is inserted through upper and lower ends of a rotor 20 having a rotor yoke 16 provided with a drive magnet 17 on the outer periphery thereof and a capstan shaft 19 rotatably. A bearing holder 3 provided with bearings 14 and 15 and a stator 10 in which a coil 8 is wound around a core 7 having salient poles arranged at a predetermined distance from the drive magnet 17 and attached to the bearing holder 3 are provided. In the provided capstan motor 1, a thrust cap 30 is provided above the bearing holder 3, and a stop ring 24 that supports the capstan shaft 19 and the rotor 20 in the thrust direction is provided above the thrust cap 30. The bearing holder 3 and the thrust cap 30 are provided with threaded portions, respectively, Formed to be in, the rotor 20
Adjustment of the gap in the thrust direction by the thrust cap 3
The present invention is to provide a capstan motor 1 which is driven by zero rotation.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a capstan motor according to the present invention will be described below with reference to FIGS. For convenience of description, the same components as those in the related art are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a sectional structural view of a preferred embodiment of a capstan motor according to the present invention, FIGS. 2 and 3 are perspective views of a main part of a thrust cap which is a main part of the present invention, and FIG.
It is a principal part perspective view of the same bearing holder.

The stator 10 is the same as the conventional example described above, and includes a stator core 7 and a driving coil 8. The center portion of the rotor yoke 16 constituting the rotor 20 is burred so as to be on the opposite side of the stator 10, and the capstan shaft 19 is press-fitted therein. The pulley 21 is mounted on the burring-processed protrusion 16 so that the capstan shaft 19 is located at the center.
a boss 32 protruding toward the stator 10 on the outer periphery of
Which is fixed to the rotor yoke 16 by ultrasonic caulking on the stator 10 side.

The upper and lower bearings 14 and 15 are made of a copper or iron-based sintered oil-impregnated material or the like which serves as a radial bearing as described above, and are provided above and below the inner peripheral portion of the bearing holder 3. The play in the thrust direction is unavoidable due to the assembly error, the weight of the rotor, and the like. However, as described above, if the play exceeds the allowable range, the performance of the motor is affected. For example,
(About 0.1 mm).

Therefore, in this embodiment, if the play in the thrust direction is larger than the allowable range, the desired performance of the motor cannot be obtained as described above, so that the gap (play) G is adjusted. This is the solution. That is, as a specific configuration, the capstan shaft 1
A male screw 3c is formed on the upper side of the bearing holder 3 through which the thrust cap 30 is inserted, and the male screw 3c is formed inside the thrust cap 30 so as to be screwed into the male screw 3c. A female screw portion 31 having a size corresponding to the portion 3c is formed, and both are screwed together.

That is, the male screw portion 3c is provided on the bearing holder 3, the female screw portion 31 is provided on the thrust cap 30, and the upper surface portion 30 of the thrust cap 30 is provided.
Assemble so that a contacts the lower surface of the stop ring 24. As described above, since the bearing holder 3, the thrust cap 30, and the stop ring 24 are assembled, when adjusting the gap, the bearing holder 3 is used.
The gap (play) in the thrust direction can be adjusted by rotating the thrust cap 30 screwed into the male screw portion 3c in a predetermined direction.

That is, when the gap (play) G between the lower end of the lower bearing 15 and the upper surface of the ring-shaped washer 22 is larger than the allowable range, the rotation of the thrust cap 30 is adjusted to be within the allowable range. I do. This adjustment may be performed, for example, by measuring the upper end of the capstan shaft 19 before the adjustment using a height gauge, and measuring the upper end of the capstan shaft 19 again after the adjustment. When the rotation adjustment by the thrust cap 30 is completed, an adhesive or the like is applied to the outer peripheral lower end of the thrust cap 30 and the side surface of the bearing holder 3 so that the thrust between the lower bearing 15 and the ring-shaped washer 22 in the thrust direction. The size of the gap (play) G does not change.

The shape of the thrust cap 30 may be any structure as long as it can be screwed into the male screw portion 3C of the bearing holder 3. For example, three legs 32 are provided at the lower end as shown in FIG. A similar gap (play) adjusting mechanism in the thrust direction can be obtained even in a structure in which the bent portion 33 is bent to form the bent portion 33 and the female screw portion 31 is provided in the bent portion 33.

[0022]

According to the capstan motor of the first aspect, a rotor having a rotor yoke in which a capstan shaft is erected substantially in the center and a drive magnet is provided in the outer periphery, and the capstan shaft is rotatable. A coil is wound around a bearing holder provided with bearings through which the capstan shaft is inserted at the upper and lower ends thereof, and a core having salient poles disposed at a predetermined distance from the drive magnet. , A capstan motor comprising a stator attached to the bearing holder,
A thrust cap is provided above the bearing holder, and a stop ring that supports the capstan shaft and the rotor in the thrust direction is provided above the thrust cap, and a screwing portion is provided on each of the bearing holder and the thrust cap. Since the gap adjustment in the thrust direction of the rotor is performed by the rotation of the thrust cap, even if there is a variation in the precision of parts, adjustment can be performed after assembly. Further, since the gap adjustment in the thrust direction of the rotor is performed by rotating the thrust cap in a predetermined direction, there is no backlash in the thrust direction, so that the rotor position does not change in the thrust direction. ,
Since there is no change in motor characteristics or damage to the tape,
High-precision tape running becomes possible.

[Brief description of the drawings]

FIG. 1 is a sectional structural view showing an embodiment of a capstan motor according to the present invention.

FIG. 2 is a perspective view of a main part of a thrust cap which is a main part of the present invention.

FIG. 3 is a perspective view of another main part of the thrust cap, which is a main part of the present invention.

FIG. 4 is a perspective view of a main part of a bearing holder which is a main part of the present invention.

FIG. 5 is a sectional structural view of a conventional capstan motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Capstan motor 3 Bearing holder 7 Core 8 Coil 10 Stator 14, 15 Bearing 16 Rotor yoke 17 Drive magnet 19 Capstan shaft 20 Rotor 24 Stop ring 30 Thrust cap

Claims (1)

[Claims] 1. A rotor having a rotor yoke in which a capstan shaft is provided upright at a substantially central portion and a drive magnet is provided at an outer peripheral portion, and said rotor is provided at upper and lower ends thereof to rotatably hold the capstan shaft. A bearing holder provided with a bearing through which a capstan shaft is inserted, and a stator having a coil wound around a core having salient poles arranged at a predetermined distance from the drive magnet and attached to the bearing holder. In the capstan motor, a thrust cap is provided above the bearing holder,
The capstan shaft and a stop ring for supporting the rotor in the thrust direction are provided on the upper portion of the thrust cap, and the bearing holder and the thrust cap are provided with respective threaded portions to be integrally formed. The gap adjustment in the thrust direction is performed by rotating the thrust cap.