JPH07231467A - Vibrator for vibration generator for small radio call device - Google Patents

Abstract

PURPOSE:To ensure a sufficient strength against extraction and to obtain desired vibration without causing a crack or the like to a tightening section even when the vibrator is fixed to a small motor output shaft especially. CONSTITUTION:A mount hole 11 to which a drive shaft of a motor is inserted is formed to an eccentric position of the vibrator. Furthermore, a ratio H/R of a axial length of the mount hole 11 to a maximum radius R from the axial line till an outer circumference is selected to be 1.6 or over.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrator mounted on a vibration generator of a small wireless calling machine.

[0002]

2. Description of the Related Art In recent years, as a type of a paging type small-sized wireless interrogator, a type having a built-in vibration generator in which a vibrator made of a metal of high specific gravity is eccentrically fixed is becoming popular as a rotary shaft of a motor. In a device having such a built-in vibration generator, the vibration is generated by the vibrator instead of making a ringing sound, thereby making it known to others even when crowded or during a meeting, for example. There is an advantage that the reception can be confirmed without being blocked.

FIG. 3 shows an example of a conventional vibration generator to which this type of vibrator is attached. In FIG. 3, reference numeral 1 indicates a small motor connected to a signal generation circuit of a small radio, and a fan-shaped vibrator 3 is formed on a rotation shaft 2 of the motor 1 at an eccentric position thereof. The rotary shaft 2 is inserted into the attached mounting hole 4 and is fixed to the rotary shaft 2 by swaging at one point on the outer peripheral portion. Here, the conventional vibrator 3 is formed into the desired fan-shaped plate shape by powder metallurgy (dry press molding method) after appropriately mixing W powder, Ni powder, Cu powder, Fe powder, or the like. It is made of a so-called high specific gravity metal having a specific gravity of about 17 to 19 g / cm ³ . The vibrator 3 is fixed to the rotary shaft 2 with a desired pulling strength by caulking with a load of about 300 kgf at one point on the outer peripheral portion thereof. By the way, in the above-mentioned conventional vibration generator, the outer diameter of the casing of the motor ₁ is 6 to 12 mm, and as the vibrator 3, the length H ₁ of the mounting hole 4 in the axis C direction is 3 to 6 mm. What has a maximum radius R ₁ from the axis C to the outer circumference in the range of 2.5 to 5.5 mm is fixed to the rotary shaft 2 of the motor 1.

[0004]

By the way, in recent years, in such a vibration generator, there is an increasing demand for downsizing or thinning of the entire device. Therefore, if the vibration generator itself is to be made smaller or thinner, the casing of the motor 1 is required to be further reduced in diameter and the maximum radius R ₁ of the vibrator 3 must be reduced. However, for example, when the outer diameter of the casing of the motor 1 becomes 5 mmφ or less due to the downsizing of the motor 1, the maximum radius R ₁ of the vibrator 3 is unavoidably set to 2.5 mm or less, and as a result, the vibration of the vibrator 3 is increased. The thickness t of the tightened part is 0.
It becomes less than 5 mm, so like the conventional one,
When the vibrator 3 is to be caulked with a load of about 300 kgf, cracks are generated in the thin caulking portion, or local stress acts on the rotating shaft 2 during the caulking process. However, there is a problem that it is easily deformed.
Therefore, if you try to increase the wall thickness t of the crimped portion,
The amount of eccentricity of the vibrator becomes small and the total weight increases, but there is a problem that desired vibration cannot be obtained. The present invention has been made to effectively solve the problems of the above-described conventional vibrator, and even when the motor is downsized, cracks or the like are generated in the caulking portion when fixing to the rotary shaft. It is an object of the present invention to provide a vibrator for a vibration generator of a small-sized wireless interrogator, which is capable of ensuring a sufficient pull-out strength without causing a vibration and obtaining a desired vibration.

[0005]

A vibrator for a vibration generator of a compact wireless interrogator according to the present invention has a mounting hole formed at an eccentric position into which a rotation shaft of a motor is inserted, and an axis line of the mounting hole. It is characterized in that it is molded to a dimension such that the ratio H / R of the directional length H to the maximum radius R from the axis to the outer circumference is 1.6 or more. Here, it is preferable that the vibrator is molded by an injection molding method.

[0006]

According to the vibrator for a vibration generator of a small radio caller having the above-mentioned structure, the axial length H with respect to the maximum radius R is significantly longer than that of the conventional vibrator. When fixing to the rotating shaft, it is possible to crimp at a plurality of positions in the axial direction. In addition to this, since the contact area between the motor rotating shaft and the vibrator after fixing is large, the frictional force generated between them becomes large, so it is possible to obtain a large pulling strength with a small crimping load. Become. Therefore, due to the synergistic effect of the large frictional force due to these contacts and the fact that they are crimped at multiple points, the crimping load per point for obtaining the desired drawing strength can be made significantly smaller than that of the conventional one. Since it becomes possible, even if the thickness of the crimped portion becomes thin, there is no possibility of cracks.

Further, at the time of caulking, the motor rotating shaft is prevented from being deformed in the direction orthogonal to the axial direction by the inner wall of the mounting hole of the vibrator, which is combined with the fact that the caulking load is small. The motor rotation shaft is not deformed. Furthermore, since the axial length H of the mounting hole is relatively long, it is possible to secure a large weight as a whole with a small maximum radius R, which is particularly used when downsizing and thinning the vibration generator. Is suitable.

The reason why the dimension ratio H / R is set to 1.6 or more will now be described. For example, in the case of a motor fixed to a small motor having an outer diameter of about 4 mmφ, the above-mentioned dimensions of the vibrator are If the ratio H / R is less than 1.6, the axial length H becomes about 2 mm,
It becomes difficult to crimp at multiple points. In addition, since a sufficient frictional force cannot be obtained between the motor rotation shaft and the vibrator, the caulking load becomes large in order to obtain a sufficient drawing strength. As a result, at one point, the vibrator must be fixed to the motor rotation shaft with a large caulking load, but on the other hand, the thickness of the caulking part becomes about 0.5 mm, so that the caulking part of the vibrator is ended up. In the present invention, cracking is likely to occur, the pulling strength is improved by increasing the contact frictional force described above, and the caulking load is thereby reduced, and further the caulking load at one point is reduced by caulking at a plurality of locations. This is because the synergistic effect cannot be obtained and it is inappropriate. When the above dimensional ratio is 1.6 or more, when this is molded by the conventional press molding method,
In particular, it is desirable to perform the injection molding method because cracks are likely to occur during molding in the thin portion and the dimensional accuracy is reduced particularly in the thin portion due to variations in the molding density.

[0009]

1 and 2 show an embodiment of a vibrator for a vibration generator of a small wireless calling machine according to the present invention. In these drawings, the vibrator 10 is made of a super-polymerized gold material having a specific gravity of about 17 to 19 g / cm ³ which is molded by an injection molding method, and a mounting hole into which the rotation shaft of the motor is inserted at an eccentric position thereof. 11 is formed. In this vibrator 10, the length H of the mounting hole 11 in the axis C direction and the maximum radius R from the axis C to the outer circumference are
And the ratio H / R is 1.6 or more.

Here, the injection molding method for molding the vibrator 10 will be described. First, a predetermined amount (about 40% by volume) of a binder is added to W powder, Ni powder, Cu powder, Fe powder or the like as appropriate. After mixing, add 100
It is preferable to mold the vibrator 10 by injection molding at an injection pressure of up to 2000 kgf / cm ² , debinding and sintering.

Here, the injection pressure is 100 to 2000.
was a kgf / cm ^2, when the injection pressure is less than 100 kgf / cm ^2, is unsuitable to unfilled portion of so-called short shot to the molded article occurs, is the injection pressure in the opposite 2,000 kgf / When it exceeds cm ² , when the molded product is projected from the mold, the friction between the mold and the mold becomes too large, and the molded product is damaged or deformed, which is inconvenient. In this way, the normal press molding pressure (2500-250)
4000kgf / cm ²⁾ than low 100~2000kgf / cm ²
By molding at an injection pressure in the range, cracks do not occur and the vibrator 10 can be obtained with high dimensional accuracy.

In the vibrator 10 for the vibration generator having the above-described structure, the rotary shaft of the motor is inserted into the mounting hole 11 and is fixed to the motor rotary shaft by caulking at the outer peripheral portion at a plurality of positions in the axial direction. And is used as a vibration generator. Therefore, such a vibrator 10
According to this, since the length H in the axial direction with respect to the maximum radius R is significantly larger than that of the conventional one, it can be fixed to the motor rotating shaft by caulking at a plurality of positions in the axial direction. In addition, since the contact area between the motor rotating shaft after fixing and the inner wall of the mounting hole 11 of the vibrator 10 is large, the frictional force generated between them becomes large, and as a result, a large pulling strength due to a small crimping load. Can be obtained. Therefore, due to the synergistic effect of large frictional force at the time of fixing and caulking at a plurality of points, it is possible to significantly reduce the caulking load per point for obtaining the desired drawing strength. Even if the thickness of the tightened portion is reduced, there is no risk of cracks in the crimped portion of the vibrator 10.

Further, when the vibrator 10 is fixed to the motor rotation shaft by caulking, the motor rotation shaft inserted into the mounting hole 11 of the vibrator 10 is orthogonal to the axial direction by the inner wall of the mounting hole 11. Since the deformation in the rotating direction is suppressed, there is no possibility of deformation of the motor rotating shaft in combination with the small caulking load. In addition, mounting hole 1
Since the axial length H of 1 is relatively longer than the conventional one as compared with the maximum radius R, a large maximum weight can be secured for the vibrator 10 with a small maximum radius R, so that the vibration is reduced. It is possible to reduce the size and thickness of the generator. Further, by molding the vibrator 10 by an injection molding method, it is possible to obtain the vibrator 10 without generation of cracks and with high dimensional accuracy.

[0014]

As described above, the vibrator for a vibration generator of a compact wireless interrogator according to the present invention has a mounting hole into which an axis of rotation of a motor is inserted and which is formed at an eccentric position. Since the ratio H / R of the axial length H and the maximum radius R from the axis to the outer circumference is 1.6 or more, caulking at multiple points causes cracks and the like in the caulking portion. The vibration generator can be fixed to the motor rotating shaft without any damage, sufficient pull-out strength can be secured, and desired vibration can be obtained. Therefore, the vibration generator can be downsized and thinned. .
Further, if the above-mentioned vibrator is molded by injection molding, the vibrator can be obtained with high dimensional accuracy without causing cracks during manufacturing.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a vibrator for a vibration generator of a compact wireless interrogator according to the present invention.

FIG. 2 is a front view showing the vibrator of FIG.

FIG. 3 is a vertical cross-sectional view showing a state in which a conventional vibrator is attached to a motor.

[Explanation of symbols]

 1 Motor 2 Motor rotating shaft 10 Oscillator 11 Mounting hole H Length of mounting hole in axial direction R Maximum radius

Claims (2)

[Claims] 1. A vibrator for a vibration generator of a small wireless interrogator, which is eccentrically fixed to a rotating shaft of a motor by swaging, wherein the rotating shaft of the motor is inserted at an eccentric position of the vibrator. The mounting hole is formed, and the mounting hole is formed to have a ratio H / R that is 1.6 or more between the axial length H of the mounting hole and the maximum radius R from the axis to the outer circumference. A vibrator for a vibration generator of a small wireless caller. 2. The vibrator for a vibration generator of a compact wireless interrogator according to claim 1, wherein the vibrator is molded by an injection molding method.