JP2001129479A - Eccentric sash weight for vibration motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute the entire part of a sash weight so as to obtain necessary vibration energy with lightweightness and smaller electric power consumption and to provide the sash weight which is inexpensive in terms of material with easy fabricating and molding. SOLUTION: This sash weight is divided to a cylindrical shaft holding part 1 which has a bearing hole 1a to be inserted and held with a motor shaft 5 in its central part and an approximately half tubular sash weight body part 2 of an approximately sectorial shape of a thickness covering a part of the outer flank of a bearing part 1. The shaft holding part 1 is formed of a metallic material of a low specific gravity which is a highly tough metallic material and the sash weight body part 2 is formed of a metallic material of a high specific gravity. This sash weight body part 2 is joined and fixed integrally to a part of the outer flank of the shaft holding part 1.

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 a vibration motor for notifying an incoming call by silent vibration in, for example, a pager or a portable telephone.

[0002]

2. Description of the Related Art Generally, an eccentric weight F of a vibration motor M represented by a small-diameter cylindrical coreless motor as shown in FIG. 7 is made of a sintered alloy of a tungsten material having a high specific gravity.
The whole weight is formed so as to present an integral fan shape in which a bearing hole C for inserting and holding the motor shaft S of the vibration motor M is disposed at an eccentric position. The eccentric weight F is attached to the shaft tip side of the motor shaft S by crimping by deforming the bearing hole C by applying an external force from a thin side surface of the bearing hole C through which the motor shaft S is inserted.

[0003] The eccentric weight can be started with a small amount of power consumption because a very small vibration motor mounted on a pager or a mobile phone uses a dry battery or a secondary battery as a power source, and the required vibration amount is sufficiently large. To achieve this, it is desirable that the entire motor or the weight portion be made lightweight and compact.

However, in the above-described eccentric weight, the entire weight is made of an integral type tungsten alloy and is heavy in weight. Therefore, the entire weight is designed and configured so as to obtain a necessary amount of vibration by obtaining a starting torque with a small power consumption. Difficult to do. Also,
As a material, a high specific heavy metal such as a tungsten alloy is used for dimensional control of bearing holes after sintering, cracking in the crimping process,
There are problems such as improper fixing, quality control is extremely difficult in manufacturing, and the material itself is expensive, resulting in a high cost due to a decrease in yield.

As described above, since the entire weight is an integrated metal part of a small sintered alloy, cracks and the like due to external pressure of a thin portion are easily generated when the thin portion is caulked to a small-diameter motor shaft. It is difficult to form the hole diameter with high accuracy by sintering, and it is easy to cause detachment from the motor shaft.

In addition, in order to obtain a predetermined vibration amount,
Since the entire weight is formed so as to have a substantially fan-like shape that is largely eccentric from the mounting bearing hole and protrudes in the circumferential direction, there is also a limit in reducing the radial dimension around the motor shaft.

[0007]

SUMMARY OF THE INVENTION According to the present invention, the weight as a whole is made light so that the required amount of vibration (energy) can be sufficiently obtained with low power consumption. Provides an eccentric weight for a vibration motor that is inexpensive and has a shape that is easy to mold the high specific heavy metal of the weight main body, is inexpensive in manufacturing and material costs, is easy to assemble, and has a simple configuration. The purpose is to do.

It is another object of the present invention to provide an eccentric weight for a vibration motor which can be configured to sufficiently obtain necessary vibration energy even when the size of the weight around the motor shaft in the rotation radial direction is reduced. And

Further, the weight of the present invention can prevent the occurrence of cracks or the like due to external pressure (pressure) when caulking the motor shaft, and can form the bearing hole with high precision in the diameter of the bearing hole, and can be detached from the shaft. It is an object of the present invention to provide an eccentric weight for a vibration motor which can be configured so as to prevent occurrence of the like.

[0010]

According to a first aspect of the present invention, there is provided an eccentric weight for a vibration motor according to the first aspect of the present invention. The shaft holding part is formed of a material having a low specific gravity, and the weight main body is formed of a material having a high specific gravity. It is constituted by integrally joining and fixing a thick, substantially pipe-shaped weight main body to the outer surface of the shaft holding portion on the inner diameter side.

According to a second aspect of the present invention, there is provided an eccentric weight for a vibration motor, which has a thick, substantially semi-pipe-like shape having a projecting portion extending from an end of a short and long shaft holding portion in a direction close to the motor housing. The weight main body is configured by joining and fixing integrally the end portion of the weight main body and the shaft holding portion.

In the eccentric weight for a vibration motor according to a third aspect of the present invention, the shaft holding portion is formed of stainless steel having a low specific gravity, and the main body of the weight is formed of a sintered alloy of a tungsten-based alloy having a high specific gravity. The weight main body is integrally fixed to the outer surface of the shaft holding portion made of a metal material having excellent toughness by a brazing portion.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an eccentric weight for a vibration motor according to the present invention; FIG.
As shown in the figure, the bearing comprises a cylindrical shaft holding portion 1 having a bearing hole 1a at the center portion thereof, and a weight-like, substantially semi-pipe-shaped weight body 2 covering a part of the outer surface of the bearing portion 1. . The bearing portion 1 and the weight main body 2 are formed separately from different materials, and the weight main body 2 is integrally joined to a part of the outer surface of the shaft holding portion 1 to form an eccentric weight.

As shown in FIG. 3, the bearing portion 1 is formed of a metal material having a low specific gravity such as stainless steel made of a metal material having excellent toughness since it is cylindrical and does not participate in the generation of vibration. In contrast, the weight body 2 is
As shown in FIG. 4, it is a substantially half-pipe wall-shaped, substantially fan-shaped portion, and is formed of a sintered alloy such as a tungsten-based alloy having a high specific gravity as a portion involved in the generation of vibration causing eccentricity.

The two parts 1 and 2 can be firmly joined and fixed by joining together a relative surface covering the outer side surface of the bearing part 1 with the brazing part 3. The entire weight is preferably covered with a plating film of electroless nickel plating, and together with corrosion resistance, the joining strength can be further increased and the joining portion can be concealed.

In the eccentric weight for a vibration motor configured as described above, the weight main body 2 is formed as a thick semi-pipe-shaped and substantially sector-shaped part involved in the generation of vibration, and is made of a sintered material such as a tungsten-based alloy having a high specific gravity. Since the shaft holding part 1 which is formed of a bonding metal and which is cylindrical and does not contribute to the generation of vibration is formed of a low specific gravity material such as stainless steel made of a metal material having excellent toughness, the weight as a whole is lightweight and material. In addition, it can be configured so that the required vibration amount can be obtained with low manufacturing cost and low power consumption.

The eccentric weight is preferably provided with a weight main body 2 having an overhang 2a extending from the end of the shaft holder 1 in the direction of approaching the motor housing 4, as shown in FIG. Since the weight main body 2 has the overhang portion 2a, even if the weight main body 2 is formed thin, a weight capable of generating necessary vibration energy can be secured, and the diameter of the eccentric weight around the motor shaft 5 can be secured. The size in the direction can be kept small, and the whole motor including the weight portion can be configured to have a small diameter.

As described above, the overhang portion 2a can generate necessary vibration energy as a whole weight even if a space portion is provided on the inner side of the motor housing 4 except for the joint portion with the shaft holding portion 1. Weight can be secured. Further, by providing the step portion 2b between the overhang portion 2a and the shaft holding portion 1, it is possible to form a relief portion for preventing the weight main body 2 from contacting the bearing portion 6 protruding from the motor housing 4.

The weight main body 2 is shifted in the direction shown in FIG. 6 so that the position of the joint portion with the shaft holding portion 1 is changed so that the weight main body 2 is connected to the overhang portion 2a on the motor housing 4 side. Even with the mounting structure having the overhang portion 2c on the opposite side, a weight capable of generating necessary vibration energy can be secured as the whole weight.

The shaft holder 1 is preferably provided with a stainless steel member made of a metal material having excellent toughness. As a result, not only can the weight of the eccentric weight be reduced and it can be made inexpensive, it can also prevent cracks and the like from occurring when caulking to the motor shaft, and the precision of the diameter of the bearing hole can be improved by machining. It can be prevented from being formed and coming off.

[0021]

As described above, according to the eccentric weight for a vibration motor according to the first aspect of the present invention, a cylindrical shaft holding portion provided with a bearing hole for inserting and holding a motor shaft at the center thereof, It is divided into a thick, approximately pipe-shaped, approximately fan-shaped weight body that covers a part of the outer surface, and the shaft holding part is formed of a metal material having a low specific gravity, and the weight body is formed of an alloy material having a high specific gravity. By forming the weight body portion and integrally fixing the weight body portion to the outer surface of the shaft holding portion, a lightweight and inexpensive device that can obtain necessary and sufficient vibration energy with low power consumption can be obtained.

Further, according to the eccentric weight for a vibration motor according to the second aspect of the present invention, the weight main body having a projecting portion extending from the end of the shaft holding portion in the direction close to the motor housing is defined as the shaft holding portion. By being integrally joined, it is possible to obtain a necessary amount of vibration even if the radial dimension around the motor shaft is kept small.

According to the eccentric weight for a vibration motor according to claim 3 of the present invention, the shaft holding portion is formed of a stainless steel having a low specific gravity, which is a metal material having excellent toughness, and a main body of the weight is formed of a tungsten having a high specific gravity. By using a sintered alloy of the base alloy, the weight body can be firmly joined and fixed to a part of the outer surface of the shaft holding part by brazing, and the weight of the entire weight can be reduced to reduce the manufacturing cost. Not only can it be constructed in a simple manner, but also when it is crimped to the motor shaft, it can prevent cracking problems etc. peculiar to sintered alloys with low toughness and high specific gravity, and can precisely machine the hole diameter of the bearing hole by machining. Can be formed,
It can be configured so as to prevent detachment from the motor shaft or the like.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a configuration of an eccentric weight for a vibration motor according to the present invention.

FIG. 2 is a front view showing a configuration of an eccentric weight for a vibration motor according to the present invention.

FIG. 3 is a front view showing a shaft holding portion constituting the eccentric weight for the vibration motor of FIG. 1;

FIG. 4 is a front view showing a weight body constituting the eccentric weight for the vibration motor of FIG. 1;

FIG. 5 is a side view partially showing a vibration motor including the eccentric weight for the vibration motor of FIG. 1;

FIG. 6 is a side view partially showing a vibration motor including an eccentric weight for a vibration motor having another shape.

FIG. 7 is a perspective view showing a vibration motor including an eccentric weight for a vibration motor according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Axis holding part 1a Bearing hole 2 Weight body part 2a Overhang part 3 Brazing part 4 Motor housing 5 Motor shaft 6 Bearing part

Claims (3)

[Claims] 1. A cylindrical shaft holding portion provided with a bearing hole at the center thereof for inserting and holding a motor shaft, and a thick semi-pipe-shaped weight body portion covering a part of an outer surface of the shaft holding portion. The shaft holding part is formed of a material having a low specific gravity, the weight body is formed of a material having a high specific gravity, and the thick, substantially semi-pipe-shaped weight body is formed on the outer surface of the shaft holding part on the inner diameter side. An eccentric weight for a vibration motor, wherein the eccentric weight is integrally joined and fixed to the body. 2. A thick, substantially pipe-shaped weight body having a projecting portion extending in the direction of approach to the motor housing from an end of the short and long shaft holding portion. The eccentric weight for a vibration motor according to claim 1, wherein the eccentric weight is integrally joined and fixed. 3. The shaft holding portion is formed of stainless steel having a low specific gravity, the weight body is formed of a tungsten-based sintered alloy having a high specific gravity, and the weight body is formed of a metal material having excellent toughness. 3. The eccentric weight for a vibration motor according to claim 1, wherein the eccentric weight is integrally fixed to an outer surface of the holding portion by a brazing portion.