JPH083156Y2 - Small motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a small motor, and more particularly to a small motor capable of flattening the entire mechanism using the small motor.

(Prior Art) In various mechanisms using a small motor, such as a capstan drive mechanism of a tape recorder, a pulley is often fixed to a rotation shaft of the motor. Further, in recent years, flattening of various mechanisms is often required, and flattening of the motor peripheral portion including the pulley is required in addition to flattening of the motor itself.

FIG. 4 shows an example of a conventional small motor used for a capstan mechanism of a tape recorder. In FIG. 4, at the center of the bottom of a bottomed cylindrical stator case 3 with one end open, a cylindrical protrusion 3c opened by punching and drawing is formed outward, and the cylindrical protrusion 3c The metal bearing 2 is fitted and fixed on the inner peripheral side.
The open end side of the stator case 3 is closed by a side plate 12. In the center of the side plate 12, a closed cylindrical protrusion 12a is formed.
Are formed outward by drawing, and the thrust bearing washer 8 is dropped into the inner bottom portion of the cylindrical protruding portion 12a, and the metal bearing 7 is dropped from above, and the metal bearing 7 is It is fitted and fixed to the inner peripheral side of the cylindrical protruding portion 12a. The two bearings 2 and 7 rotatably support a rotary shaft 9. One end of the rotary shaft 9 abuts the thrust receiving washer 8 to support the load in the thrust direction. The other end of the rotating shaft 9 penetrates through the bearing 2 and projects to the outside of the stator case 3, and the pulley 1 is fixed to this projecting end. The pulley 1 is made of resin, for example, and is fixed to the rotary shaft 9 by press fitting or adhesion. The pulley 1 has a V-shaped circumferential groove on which a belt is hung. The driving force is transmitted to various mechanisms, such as a capstan mechanism of a tape recorder, via the belt. A rotor R having a rotor core 5 and a drive coil 6 is housed in the stator case 3, and a rotary shaft 9 penetrates and is fixed to the center of the rotor R. Furthermore, the rotating shaft 9
On both sides of the rotor core 5 with 10 and collar 13
Are fitted and fixed. The rotor core 5 has a plurality of salient poles, and a drive coil 6 is wound around each salient pole.
The outer peripheral surface of each salient pole faces the inner peripheral surface of the magnet 4 fixed to the inner peripheral surface of the stator case 3 with a predetermined gap. The magnet 4 has an appropriate number of magnetic poles in the circumferential direction. The tip of the brush 11 is in sliding contact with the outer peripheral surface of the commutator 10, and power is supplied to the drive coil 6 corresponding to the rotational position of the rotor through the brush 11 and the commutator 10. The bottom outer surface of the bottomed cylindrical stator case 3 is a flat surface, and this flat surface serves as a reference surface 3a that serves as a reference when mounting the motor on various mechanisms and devices. It is known that the device has a structure in which the device is directly attached to the reference surface 3a and that the device is attached to another device with the reference surface 3a as a reference. Since the principle of rotation of the motor configured as described above is well known, description thereof will be omitted.

Next, another example of the conventional small motor shown in FIG. 5 will be described. This conventional example is different from the conventional example shown in FIG.
A hole is simply formed without providing a cylindrical protrusion at the center of the bottom of the bottomed cylindrical stator case 3, and a metal bearing 2 with a collar is fixed by caulking or the like to support the rotating shaft 9. , The cylindrical projection 12b is provided on the inner surface side of the side plate 12 without providing the cylindrical projection outward in the center of the side plate 12, and the metal bearing 2 is fixedly fitted to the inner peripheral side of the cylindrical projection 12b. In addition to supporting the rotary shaft 9, the inner side surface of the side plate 12 itself serves as a thrust receiver to abut one end of the rotary shaft 9. Other configurations and the principle of rotation are the same as those in the example of FIG.

(Problems to be solved by the invention) In any of the conventional examples shown in FIG. 4 and FIG.
Various measures have been taken to flatten the entire motor including. In the example of FIG. 4, the protrusion amount a of the cylindrical protrusion 3c on the stator case 3 side from the reference surface 3a is reduced as much as possible, and in the example of FIG. 5, the protrusion amount b of the bearing 2 from the reference surface 3a is reduced. I try to reduce it as much as possible.

However, as in the example of FIG. 4, the cylindrical protrusion 3c has a reference surface.
The protrusion itself from 3a and the protrusion of part of the bearing 2 from the reference surface 3a itself as in the example of FIG. 5 are factors that obstruct the flattening of the entire motor. That is, the fourth
In the example of the figure, when the dimension from the reference surface 3a to the end surface of the pulley 1 facing it is c and the dimension from the reference surface 3a to the axial center of the pulley 1 is La, these dimensions c and La are
This is because the protrusion amount a of the cylindrical protrusion 3c from the reference surface 3a is added, and the protrusion amount of the pulley 1 from the reference surface 3a increases. In the example of FIG. 5, the dimension from the reference surface 3a to the end surface of the pulley 1 facing the reference surface 3a is d, and the reference surface 3a
Let Lb be the dimension from the center of the pulley 1 in the axial direction,
This is because these dimensions d and Lb are dimensions obtained by adding the protrusion amount b of the cylindrical protrusion 3c from the reference surface 3a, and the protrusion amount of the pulley 1 from the reference surface 3a increases. Moreover, since the width of the belt to be hung on the pulley 1 is narrower than the width of the pulley 1, there is a problem that a large dead space is generated between the reference surface 3a and the belt.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and makes it possible to reduce the mounting height of the pulley with respect to the rotary shaft without reducing the physical size of the motor itself, and to include the motor. It is an object of the present invention to provide a small motor capable of flattening the entire mechanism.

(Means for Solving the Problems) The present invention provides a stator case, a rotor, a rotating shaft,
A small motor that has a bearing that is fixed to the stator case and supports the rotating shaft, and a pulley that is attached to the part of the rotating shaft that protrudes outside the stator case, and that uses the surface of the stator case facing the pulley as the reference surface. At the portion of the stator case that faces the pulley, a recessed portion that is recessed toward the rotor is provided over a wider area than the projection surface of the pulley, and the bearing is disposed in this recessed portion, so that the bearing is It is characterized in that it is arranged closer to the rotor than the reference plane.

(Function) The reference surface of the stator case is recessed toward the rotor over a wider area than the projection surface of the pulley to form a recessed portion, and the bearing is arranged in this recessed portion, so that the bearing is more than the reference surface. Since it is arranged on the rotor side, the pulley can be brought closer to the reference surface side.

(Embodiment) An embodiment of a small motor according to the present invention will be described below. Since the structure of the embodiment of the small motor according to the present invention is common in many parts with the structure of the conventional example shown in FIGS. 5 and 6, common parts are designated by common reference numerals. However, the characteristic components will be mainly described.

In FIG. 1, in a bottomed cylindrical stator case 3, a roller R having a rotor core 5, a drive coil 6 and the like similar to the conventional example shown in FIG. 5 is housed, and the rotor R is rotated. The shaft 9 is fixed, and the rotating shaft 9 is rotatably supported by the metal bearing 2 fixed to the stator case 3 and the metal bearing 7 fixed to the side plate 12. Also,
A pulley 1 is attached to a portion of the rotating shaft 9 protruding outside the stator case 3, and a plane of the stator case 3 facing the pulley 1 serves as a reference surface 3a.

The embodiment shown in FIG. 1 corresponds to the structure of the conventional example shown in FIG. 5, but the embodiment shown in FIG. 1 differs from the example shown in FIG. 5 in that it has a bottomed cylinder facing the pulley 1. The reference surface 3a of the stator case 3 is recessed toward the rotor over a wider area than the lateral projection surface of the pulley 1 to form the recessed portion 3e. This is the point arranged on the rotor side. The bearing 2 has the above-mentioned depression 3e.
It is fitted and fixed to a cylindrical portion 3f that is formed to project toward the rotor by punching and drawing in the center of the. The bottom surface of the depressed portion 3e is no longer provided as a reference surface for mounting the motor.

According to the embodiment of FIG. 1 configured as described above, the recessed portion 3e that is recessed toward the rotor is formed in the reference surface 3a of the stator case 3 over a wider range than the projection surface of the pulley 1 in the axial direction. Since the bearing 2 on the pulley 1 side is arranged closer to the rotor than the reference surface 3a, the pulley 1 can be arranged close to the depression 3e. Therefore, the dimension L from the reference surface 3a to the axial center of the pulley 1 can be reduced, and the entire mechanism including the motor can be flattened.

Next, various modified embodiments of the small motor according to the present invention will be described.

The embodiment shown in FIG. 2 has a corresponding relationship with the structure of the conventional example shown in FIG. 6, but the embodiment shown in FIG. 2 differs from the example shown in FIG. 6 in the case of the embodiment shown in FIG. Similarly, by forming a depression 3e on the reference surface 3a of the bottomed cylindrical stator case 3 facing the pulley 1 over a range wider than the axial projection surface of the pulley 1, a depression 3e is formed. 1
That is, the bearing 2 on the side is arranged closer to the rotor than the reference surface 3a. Then, the metal bearing 2 with a collar is fitted in a hole formed in the center of the recess 3e, and the outer end of the metal bearing 2 is caulked to the edge of the hole to fix the metal bearing 2. are doing. Also in the case of this embodiment, the pulley 1 can be arranged close to the depression 3e,
The dimension L from the reference surface 3a to the axial center of the pulley 1 can be reduced, and the entire mechanism including the motor can be flattened.

Here, the depth of the depression 3e in the embodiment shown in FIGS. 1 and 2 will be examined with reference to FIG. The minimum permissible range of the gap 1 between the reference surface 3a of the stator case 3 that is the motor mounting surface and the rubber belt 15 that is hung on the pulley 1 is smaller than that of the belt 15 in a small flat mechanism such as that found in a headphone tape recorder. It is about 0.5 mm considering run-out, and it is not desirable to make it smaller than this. The rubber belt of the small flat mechanism is generally 1 mm square, and it is sufficient that the axial dimension l'of the flange portion of the pulley 1 is about 0.3 mm on one side of the belt 15. Therefore, the thickness dimension (axial dimension) W of the pulley 1 in this case is the dimension obtained by combining the diagonal dimension of the 1 mm square belt 15 and the dimension of the flange portion of the pulley 1 × 2, that is, W = 1.4. It becomes + 0.3 × 2 = 2 (mm). The gap between the motor reference surface 3a and the pulley 1 is (l-
1 '), and the appropriate size of this (l-1') and the depth of the depression 3e is in the range of 0.5 mm to 0.8 mm. Therefore, the depth dimension of the depression 3e is x, l = 0.5 (m
m) and l '= 0.3 (mm), 0.8 ≧ (0.5−0.3) + x ≧ 0.5 0.6 ≧ x ≧ 0.3, and the depth dimension x of the recess 3e is approximately 0.3 mm to 0.6 mm.
It means that the range of is appropriate.

(Effects of the Invention) According to the present invention, in a small motor having a pulley attached to a portion of the rotary shaft protruding outside the stator case and having a surface of the stator case facing the pulley as a reference surface, the stator case is In the portion facing the pulley, a recessed portion that is recessed toward the rotor is provided over a wider area than the projection surface of the pulley, and a bearing is disposed in this recessed portion so that the bearing is located closer to the rotor than the reference surface. Since it is arranged, the pulley can be arranged close to the reference surface side, and the entire mechanism including the motor can be flattened.

[Brief description of drawings]

1 is a front sectional view showing an embodiment of a small motor according to the present invention, FIG. 2 is a front sectional view showing another embodiment of a small motor according to the present invention, and FIG. 3 is a reference in each of the above embodiments. FIG. 4 is a front sectional view showing an example of a conventional small motor, and FIG. 5 is a front sectional view showing another example of a conventional small motor. It is a figure. 1 …… Pulley, 2,7 …… Bearing, 3 …… Stator case, 3
a: reference plane, 5: rotor, 9: rotating shaft, R: rotor.

Claims (1)

[Scope of utility model registration request] 1. A stator case, a rotor housed in the stator case, a rotary shaft fixed to the rotor, a bearing fixed to the stator case to support the rotary shaft, and a stator of the rotary shaft. A small motor having a pulley attached to a portion protruding out of the case, wherein the surface of the stator case facing the pulley is a reference surface, and the stator case has a portion facing the pulley, It has a recessed portion that is recessed toward the rotor over a wider area than the projection surface of the pulley, and by disposing a bearing in the recessed portion, the bearing is disposed closer to the rotor than the reference surface. A characteristic small motor.