JPH07336928A - Motor - Google Patents

Abstract

PURPOSE:To provide a motor for driving the shaft of a capstan, which materializes stable tape transport at low cost. CONSTITUTION:This unit 31 is composed of a bearing housing 40, which has a cut opening at a part, a thrust bearing 43, which abuts slidably on the recess provided coaxially with a motor shaft 39 at the housing 40 and the end of the motor shaft and supports the thrust fee by magnetic attraction between the stator and the rotor, and a thrust bearing retaining member, which has a claw to engage with the groove 40b and besides fixes and retains the thrust bearing 43. Hereby, the thrust bearing can be constituted without providing a screw, etc., so an inexpensive motor can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor for driving a capstan shaft used in video / audio equipment such as a video tape recorder and an audio cassette tape recorder.

[0002]

2. Description of the Related Art As a conventional motor for driving a capstan shaft, there is, for example, a first conventional motor shown in FIG. FIG. 4 is a side sectional view of the first conventional example. In the figure, the motor 1 is configured such that a first flat surface portion 2 is opposed to the first flat surface portion 2 with a predetermined gap and an annular permanent magnet 3 magnetized with a plurality of predetermined poles. The stator winding 5 is provided on a stator flat plate 4 made of a magnetic material having an electric wiring portion. The permanent magnet 3 is fixed by abutting the second flat surface portion 7 of the permanent magnet 3 on the back yoke 6 made of a magnetic material.

On the other hand, a back yoke 6 is fixed to a rotary shaft of the motor 1, that is, an end portion 8a of the capstan shaft 8 via a boss 9 so as to rotate integrally with the permanent magnet 3. The capstan shaft 8 is a bearing 11 provided on an upper portion of a bearing housing 10 attached to the stator flat plate 4.
In addition, it is fitted in a bearing 12 provided in the lower part and rotatably supported. Further, the bearing housing 10 is provided with a cutout opening 10a in a part of its intermediate portion, and the capstan shaft 8 can come into contact with a tape (not shown) and the pinch roller 13 through the cutout opening 10a. It is done like this. Also, the end surface portion 9a of the boss 9
Is in contact with the bearing 12, and the bearing 12 receives the thrust load due to the attraction force of the magnetic force of the permanent magnet 3. The bearing 12 provided in the bearing housing 10 is generally formed of a ball bearing, while the bearing 11 is formed of a slide bearing such as a sintered oil-impregnated alloy.

However, since the motor 16 of the first conventional example constructed as described above supports the thrust load due to the attractive force of the magnetic force of the permanent magnet 3 by the bearing 12 which is a ball bearing, it becomes very expensive. Was becoming.

When the pinch roller 13 is pressed against the capstan shaft 8 with the tape sandwiched between them, the ball bearing 12
Is always subjected to a radial load, and the outer ring 12a of the ball bearing 12 is fixed to the bearing housing 10,
The inner ring 12b of the ball bearing 12 is the capstan shaft 8
It will rotate together with. At this time, the plurality of balls 12c in the ball bearing 12 whose phases are determined by a retainer (not shown) revolve around the inner ring 12b while rotating on their own axes.

However, a minute gap is formed between the ball 12c and the outer ring 12a and between the ball 12c and the inner ring 12b.
Since there is a so-called radial gap, when the ball 12c revolves, one ball 1 is generated in the inner ring 12b that is urged in one direction by the pressure force of the pinch roller 13.
The case of being supported by 2c and the case of being supported by two balls 12c are alternately repeated, and the inner ring 12b
The axis of will move and vibrate slightly. Therefore, the capstan shaft 8 that rotates integrally with the inner ring 12b
Since the center of rotation also moves and vibrates, it becomes difficult to achieve stable tape transfer, the wow and flutter increases during tape transfer, and the performance of the recording / playback device deteriorates. There was a problem.

In order to solve these problems, a second conventional motor as shown in FIG. 5 has been proposed. FIG. 5 is a side sectional view of the second conventional example, and the same components as those described in FIG. 4 are designated by the same reference numerals. In this figure, the motor 16 differs from the motor 1 of the first conventional example in that a bearing 20 is provided in a bearing housing 19 and a capstan shaft 18 is rotatably supported.
1. A thrust bearing 22 in which 1 is composed of a sliding bearing such as a sintered oil-impregnated alloy and newly supports the capstan shaft 18 in thrust.
Is provided on the upper part of the bearing housing 19. The thrust bearing 22 is formed of a thermoplastic resin material such as polyoxide methylene or polyamide by an injection molding method or the like, and a screw portion is formed on the outer peripheral portion thereof, and is screwed into the bearing housing 19. Further, as shown in FIG. 4, the shape of the tip portion 18 a of the capstan shaft 18 is a convex spherical surface, and the tip portion 18 a is the flat surface 22 of the thrust bearing 22.
It slidably contacts a and supports thrust.

In the motor 16 of the second conventional example having such a structure, since the thrust load due to the attraction of the magnetic force of the permanent magnet 3 is supported by the newly provided thrust bearing 22, a ball bearing is used as a radial bearing. Since it is not necessary to use an expensive one such as the above, and a very inexpensive sliding bearing such as an oil-containing sintered alloy can be applied, the cost of the motor is significantly reduced.

[0009]

In the conventional motor configured as described above, the screw portion for screwing into the bearing housing 19 has to rely on machining such as cutting, resulting in cost increase. In addition, the screw portion of the outer peripheral portion of the thrust bearing 22 and the screw portion of the bearing housing 19 must be engaged with each other, and the mounting work is troublesome. Furthermore, the rotation of the screw portion causes the permanent magnet 3 and the stator to rotate. There is also a problem that the distance between the winding 5 and the winding must be adjusted.

In view of the above problems, the present invention provides an inexpensive motor for driving a capstan shaft, which realizes stable tape transfer without using an expensive bearing such as a ball bearing.

[0011]

In order to achieve the above object, the motor of the present invention comprises a motor shaft, a fixed magnetized rotor that is fixedly attached to the motor shaft and integrally rotates, and a rotor thereof. A stator flat plate facing each other, a stator including multiple stator windings applied on the stator flat plate on a concentric circle centering on the rotor to apply a rotating force to the rotor by energization, and a motor shaft. A bearing housing that has a radial bearing that is rotatably supported and that has a notched opening in a part;
A groove portion provided concentrically with the motor shaft in the bearing housing, and a thrust bearing slidably in contact with the end of the motor shaft and supporting thrust force due to a magnetic attraction force acting between the stator and the rotor. A thrust bearing holding member having a claw portion that fits in the groove portion and fixedly holding the thrust bearing.

[0012]

According to the above construction, the thrust bearing can be constructed with a simple construction, the need for adjusting the height of the rotor is eliminated, and the need for screwing the housing portion and the thrust bearing is eliminated. Therefore, the motor can be constructed at low cost.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the motor of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of a motor in one embodiment of the present invention, and FIG. 2 is an enlarged view of a main part of a thrust bearing portion in one embodiment of the present invention. In FIG. 1, the motor 31 includes an annular permanent magnet 33 magnetized with a plurality of predetermined poles on a first flat surface portion 32, and the first flat surface portion 32 facing each other with a predetermined gap. In addition, it has a stator winding 35 of a plurality of phases formed on a stator flat plate 34 made of a magnetic material having an electric wiring portion. Further, the permanent magnet 33 has a back yoke 36 made of a magnetic material and a second magnet of the permanent magnet 33.
The flat portion 37 is abutted and fixed.

On the other hand, the back yoke 3 is attached to the rotary shaft of the motor, that is, the end portion 38a of the capstan shaft 38 via the boss 39.
6 is fixed and configured to rotate integrally with the permanent magnet 33. The capstan shaft 38 is the stator flat plate 3
4, a bearing 41 provided on a bearing housing 40 attached to the bearing 4 and rotatably bearing the capstan shaft 38 and a bearing 42 are formed of a sliding bearing such as a sintered oil-impregnated alloy.
Thrust bearing 4 for thrust-supporting the capstan shaft 38
3 is provided on the top of the bearing housing 40. Further, the bearing housing 40 is provided with a cutout opening 40a in a part of its intermediate portion, and the capstan shaft 38 can abut the tape (not shown) and the pinch roller 44 through the cutout opening 40a. It is done like this.

Here, as shown in FIG. 2, the thrust bearing 4
3 is formed of a thermoplastic resin material such as polyoxide methylene or polyamide by an injection molding method or the like, and a claw portion 43a is formed on the outer peripheral portion thereof. Further, a groove portion 40b provided concentrically with the capstan shaft 38 is fitted on the outer peripheral portion of the bearing housing 40. Further, as shown in FIG. 1, the shape of the tip end portion 38a of the capstan shaft 38 is a convex spherical surface, and the tip end portion 38a slidably contacts the flat surface 43b of the thrust bearing 43 to support the thrust.

Next, the operation and action of the motor having the above structure will be described. The position of the permanent magnet 33 is detected by using a position detecting element (not shown) such as a Hall element, and when the stator winding 35 of each phase is sequentially energized according to the position, the permanent magnet 33 is generated according to Fleming's law. Receives rotational force. As a result, the capstan shaft 38 integrally formed with the permanent magnet 33 rotates. The pinch roller 4 is sandwiched between the rotating capstan shaft 38 and the tape.
When 4 is crimped, capstan shaft 38 and pinch roller 4
4 cooperate to transport the tape at a constant speed.

Further, the air gap distance between the permanent magnet 33 and the stator flat plate 34 is mechanically determined by the groove portion 40b of the bearing housing 40 and the claw portion 43a of the thrust bearing 43, and it is not necessary to adjust the air gap distance.

FIG. 3 is an enlarged view of another main part of the thrust bearing portion according to the embodiment of the present invention. As shown in FIG. 3, the thrust bearing portion may be composed of two parts, the thrust bearing 43 and the thrust bearing holding member 44. At this time, when the thrust bearing 43 is formed, the compression sinter molding method can be applied, so that a thermosetting resin such as polyimide having excellent heat resistance and abrasion resistance can be used as the thrust bearing material. Furthermore, even if it is a thermosetting resin that is more expensive than a thermoplastic resin,
Since the thrust bearing 43 can be made small,
The cost increase can be suppressed. Further, although the thrust bearing holding member 44 having the claw portion is inferior in heat resistance and wear resistance to the thermosetting resin, the injection molding method can be applied, and even if the shape is complicated, the shape can be easily changed. A thermoplastic resin such as polyoxide methylene, polyamide, or polyethylene that can be formed can be used. Therefore, the desired function of the thrust bearing can be achieved easily and rationally.

The thrust bearing 43 is compression-fired using a thermosetting resin such as polyimide, or a composite resin material in which a solid lubricant such as graphite, molybdenum disulfide or ethylene tetrafluoride is mixed with the resin material. It may be formed by a binding molding method or the like.

[0020]

As is apparent from the above description, according to the motor of the present invention, the motor shaft, the fixed magnetized rotor which is fixedly attached to the motor shaft and integrally rotates, and the rotor. A stator flat plate facing each other, and a stator including a stator winding of a plurality of phases, which is provided on the stator flat plate on a concentric circle of the center of the rotor and applies a rotational force to the rotor by energization,
A bearing housing that has a radial bearing that rotatably supports the motor shaft and has a notched opening in part, a groove portion that is concentric with the motor shaft in the bearing housing, and slides on the end portion of the motor shaft. A thrust bearing holding member that has a thrust bearing that movably abuts and supports a thrust force due to a magnetic attraction force that acts between the stator and the rotor, and a claw portion that fits into the groove portion, and that firmly holds the thrust bearing. Since the thrust bearing holding member is provided with, the thrust bearing can be configured without providing a screw portion by simply fitting the claw portion of the thrust bearing holding member into the groove portion provided concentrically with the bearing housing. It is possible to provide various motors.

[Brief description of drawings]

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

FIG. 2 is an enlarged view of a main part of a thrust bearing portion according to an embodiment of the present invention.

FIG. 3 is an enlarged view of another main part of the thrust bearing portion according to the embodiment of the present invention.

FIG. 4 is a side sectional view of a first conventional motor.

FIG. 5 is a side sectional view of a second conventional motor.

[Explanation of symbols]

 33 permanent magnet 34 stator plate 35 stator winding 38 motor shaft 40 bearing housing 40b groove 41, 42 radial bearing 43 thrust bearing 44 thrust bearing holding member

Claims (2)

[Claims] 1. A motor shaft, a fixed magnetized rotor that is fixed to the motor shaft and integrally rotates, a stator flat plate facing the rotor, and the rotor center on the stator flat plate. Of the stator, which includes a plurality of phases of stator windings that are applied to the concentric circles to apply a rotating force to the rotor by energization, and a radial bearing that rotatably supports the motor shaft. A bearing housing having a notch opening, a groove portion provided concentrically with the motor shaft in the bearing housing, and slidably abutting on an end portion of the motor shaft and acting between the stator and the rotor. A motor comprising: a thrust bearing that supports a thrust force due to a magnetic attraction force; and a thrust bearing holding member that has a claw portion that fits into the groove portion and that firmly holds the thrust bearing. 2. A motor shaft, a fixed magnetized rotor that is fixed to the motor shaft and integrally rotates, a stator flat plate facing the rotor, and the rotor center on the stator flat plate. Of the stator, which includes a plurality of phases of stator windings that are applied to the concentric circles to apply a rotating force to the rotor by energization, and a radial bearing that rotatably supports the motor shaft. A bearing housing having a notch opening, a groove portion provided concentrically with the motor shaft in the bearing housing, and slidably abutting on an end portion of the motor shaft and acting between the stator and the rotor. A thrust bearing made of a thermosetting resin that supports the thrust force of the magnetic attraction force, and a thrust bearing holding member made of a thermoplastic resin that has a claw portion that fits in the groove portion and that holds the thrust bearing firmly. Be prepared Characteristic motor.