JPH08205466A - Eccentric weight for producing centrifugal force and fixing method therefor - Google Patents

Abstract

PURPOSE: To provide an eccentric weight for producing centrifugal force, and fixing method therefor, which can be fixed easily and rigidly to a rotary shaft merely through sintering by eliminating the central hole. CONSTITUTION: The eccentric weight for producing centrifugal force being fixed to the rotary shaft of a motor has an enlarged sectoral body 1 which is provided with a shaft fitting groove 2 opening oppositely to the center of gravity side and fitted with the rotary shaft in the radial direction. Reversely tapered 3a, 3a banks 3, 3 are extended from the opposite sides of the groove 2. When the eccentric weight is fixed to the rotary shaft, the rotary shaft is fitted in the groove 2 and the banks 3 on the opposite sides are deformed to warp the rotary shaft by means of a wedge-like jig J.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eccentric weight for generating a centrifugal force of a vibration motor used as a silent calling means of a radio calling device (product name pager) and a mobile phone, and a mounting method thereof.

[0002]

2. Description of the Related Art Conventionally, it is known that a fan-shaped eccentric weight having an enlarged cross section is attached to an output shaft of a small direct current motor to obtain vibration by utilizing centrifugal force during rotation. That is, as shown in FIG. 6, an eccentric weight W made of a fan-shaped copper-tungsten alloy whose radial cross section is ginkgo or expanded is attached to an output shaft S of a motor main body M through a central hole H. Each functional component mounted on a mobile device must be able to withstand a drop impact,
Since an impact of 100 gal or more is applied to the equipment, it is necessary to give sufficient consideration to the mounting strength of a high-density member such as an eccentric weight. It is known that an anaerobic adhesive is used as a means for attaching the eccentric weight, or one in which a thin portion on the side opposite to the center of gravity is crushed to partially dig into the shaft as shown in FIG.

[0003]

However, in the structure of the conventional eccentric weight as described above, it is necessary to form the size of the central hole H in accordance with the diameter of the shaft with any of the above means. It has to be processed,
There was a cost problem.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an eccentric weight for generating a centrifugal force and a method of mounting the eccentric weight, which can be easily and firmly mounted on a rotary shaft simply by eliminating the central hole and sintering. is there.

[0005]

The above-mentioned problem is solved by claim 1.
In the eccentric weight for generating centrifugal force attached to the rotating shaft of the motor as shown in FIG. 2, a shaft fitting groove is formed which is cut open to the side opposite to the center of gravity so that the rotating shaft can be fitted in the radial direction. This can be achieved by setting up banks with at least one reverse taper on both sides of the groove. More specifically, it can be achieved by providing an escape groove into which a jig is inserted in the base portion of the bank as in the second aspect of the invention.

In order to attach such an eccentric weight to the rotary shaft, a step of placing the centrifugal force generating eccentric weight on the mounting table with the shaft fitting groove facing upward, as in the invention described in claim 3, , A step of fitting a rotary shaft of a motor into the shaft fitting groove, and a step of pressing down a press die to deform at least a part of the reverse tapered bank so as to surround the rotary shaft. Can be achieved. Further, another problem of the attaching method can be achieved by further applying a step of applying an adhesive as shown in claim 4.

[0007]

According to the means for achieving the above object, the sintered body is simply sintered and does not require a central hole, which is advantageous in terms of cost and can be fitted to the rotary shaft in the radial direction. Therefore, the mounting becomes easy. The reverse taper bank can be easily deformed so as to surround the rotary shaft by a wedge jig, so that the mounting can be made firm. According to the means for achieving the above object, the wedge-shaped jig enters the escape groove, and the stroke adjustment of the jig becomes easy.

According to the mounting method of the third aspect, the rotating shaft can be fitted in the shaft fitting groove, and the jig can be firmly mounted by a simple method of pushing down the jig from above. According to the mounting method as set forth in claim 4, the adhesive is first dripped into the shaft fitting groove with a dispenser or the like, or the rotary shaft is fitted and then the drip coating is applied, whereby a step is added to more firmly mount the adhesive. You can do it.

[0009]

1 is a perspective view showing the features of an eccentric weight for generating centrifugal force according to the present invention. The fan-shaped main body 1 which is widened as a whole is made of a copper-tungsten alloy having a density of 15 to 18.4, and a shaft fitting groove 2 having a width approximately equal to the diameter of the rotating shaft is formed in the center from the side opposite to the center of gravity. On both sides of the shaft fitting groove 2, banks 3, 3 having reverse tapered shapes 3a, 3a are provided, and escape grooves 4, 4 are provided at the bases of the banks 3, 3. The height of the banks 3 and 3 is preferably such that the rotary shaft slightly protrudes when the rotary shaft is fitted. The eccentric weight for generating centrifugal force thus formed has the rotary shaft S fitted therein as shown in FIG. 2, and then is surrounded by the wedge-shaped jigs J on both sides of the rotary shaft S as shown by imaginary lines. It can be attached by transforming it to wrap it.

Now, a method of attaching the centrifugal force generating eccentric weight to the rotary shaft of the motor will be described in detail with reference to FIG. 3, and a mounting table D having a shape corresponding to the center of gravity of the eccentric weight will be described. The eccentric weight main body 1 is placed, and the shaft fitting groove 2 is pressed by the positioning guides G from both sides so as to face upward. After that, the rotary shaft S of the motor is fitted into the shaft fitting groove, the wedge-shaped jig J is pushed down, and the banks on both sides are deformed so as to enclose the surroundings of the rotary shaft to complete the process.

In order to keep the strength higher, it is advisable to drop the anaerobic adhesive with a dispenser before or after the rotation shaft of the motor is inserted. In addition, it is not necessary that the banks on both sides entirely enclose the rotary shaft, and only a part thereof may be used. Further, the banks on both sides may be inversely tapered as shown in FIG. In the configuration of the eccentric weight in the above embodiment, the shaft fitting groove 2 is directed upward by the positioning guide of the jig, but the guide groove 5 is provided as shown in FIG. 5, and the guide groove 5 is placed on the mounting table DD. The projection DD1 may be adjusted. In this way, setting is simple and automation can be facilitated. Of course, in this case, it is desirable that the guide groove has a minimum size that serves as a guide.

[0012]

As described above, the eccentric weight for generating centrifugal force according to the present invention eliminates the central hole and allows the rotary shaft of the motor to be fitted in the radial direction. Fitting is possible. Further, according to the above-described mounting method, it is possible to mount the rotating shaft S very easily and firmly.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of an eccentric weight for generating centrifugal force of the present invention.

FIG. 2 is an explanatory view showing a state where the eccentric weight of the present invention is attached to a rotary shaft.

FIG. 3 is an explanatory diagram of a method of attaching the eccentric weight.

FIG. 4 is a plan view of another embodiment of the eccentric weight of the present invention.

FIG. 5 is an explanatory diagram of a third embodiment of the same eccentric weight and its mounting method.

FIG. 6 is a perspective view showing a configuration of an eccentric weight in a conventional vibration motor.

FIG. 7 is a perspective view showing the configuration of another eccentric weight in the conventional vibration motor.

[Explanation of symbols]

 1 Eccentric weight body 2 Shaft fitting groove 3 Bank 3a Reverse taper shape 4 Escape groove 5 Guide groove

Claims (4)

[Claims] 1. An eccentric weight for generating a centrifugal force, which is attached to a rotating shaft of a motor, is provided with a shaft fitting groove which is cut open on the side opposite to the center of gravity so that the rotating shaft can be fitted in a radial direction. An eccentric weight for generating centrifugal force, in which at least one of both sides has a reverse taper and a bank is raised. 2. The eccentric weight for generating a centrifugal force according to claim 1, wherein an escape groove into which a jig is inserted is provided at the base of the bank. 3. A method of attaching an eccentric weight for generating centrifugal force, which is attached to a rotating shaft of a motor, comprising the step of placing the eccentric weight for generating centrifugal force on a mounting table with a shaft fitting groove facing upward. Eccentricity for centrifugal force generation, which includes a step of fitting a rotary shaft into the shaft fitting groove, and a step of pressing down a press mold to deform at least a part of the reverse tapered bank so as to surround the rotary shaft. How to attach the weight. 4. The method of mounting the eccentric weight for generating centrifugal force according to claim 3, further comprising a step of applying an adhesive.