JPH0865947A - Vibration generator and fixing method for vibrator - Google Patents

Abstract

PURPOSE: To provide a vibration generator which has high connecting strength of a rotary shaft to a vibrator and does not generate a deformation like breakage at the shaft. CONSTITUTION: The end area of a vibrator 12 has a thin part in which the radial thickness of a rotary shaft 11 is reduced. The thin part is so plastically deformed as to be pressure contact with the outer surface of the shaft 11 to fix the vibrator 12 to the shaft 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration generator and a vibrator fixing method used in a small communication device or the like.

[0002]

2. Description of the Related Art In recent years, a small communication device such as a small radio calling device called a pager or a portable small telephone has become widespread. As a method of calling the communication device, there are a method of calling using sound and a method of calling using vibration.

The latter vibration generator has a rotary shaft that is driven to rotate by a drive source such as a motor and a rotary bearing insertion hole at an eccentric position, and is fixedly held by the rotary shaft inserted into this hole. And a vibrator. In this vibration generator,
Vibration is generated by rotating the rotating shaft.

The above-mentioned vibration generator is disclosed in, for example, Japanese Utility Model Publication No. 4-13860, Japanese Patent Laid-Open No. 6-98496,
JP-A-6-30544 or JP-A-6-1933.
No. 6, for example. In the vibration generators disclosed in these prior arts, the rotary shaft and the vibrator are fixed as follows. That is, holes or grooves are formed in the vibrator in advance, and the rotary shaft is inserted into the holes or grooves of the vibrator. Then, in one method, the vibrator and the rotary shaft are fixed by performing pressure processing such as caulking on the part of the vibrator surrounding the hole or groove in the radial direction of the rotary shaft. In another method, the vibrator and the rotary shaft are fixed by a bonding method such as welding.

As a material for the vibrator of the vibration generator disclosed in the above-mentioned prior art, a tungsten-based sintered alloy, which is a high specific polymerization gold, is generally used for the purpose of obtaining a vibration generator having a small size and a large vibration amount. ing.

[0006]

The above-mentioned vibration generator has the following problems.

Japanese Utility Model Publication No. 4-13860, JP-A-6-
In the vibration generator disclosed in Japanese Patent Publication No. 98496, Japanese Patent Laid-Open No. 6-30544 or Japanese Utility Model Laid-Open No. 6-19336, a method of fixing a rotary shaft of a motor and a vibrator is to form a hole from the radial direction of the rotary shaft. Alternatively, pressure processing such as caulking is applied to the portion of the vibrator surrounding the groove. A schematic diagram of this fixing method is shown in FIGS. 8 and 9.

Referring to FIG. 8, a vibrator 1 has a hole 2 for inserting a rotary bearing at an eccentric position. The rotary shaft 3 that is driven to rotate by a drive source such as a motor has a hole 2 in the vibrator 1.
Is inserted into. As shown in FIG. 9, after inserting the rotary shaft 3 into the hole 2 of the vibrator 1, a large pressing force P is applied to the portion of the vibrator 1 surrounding the hole 2 in the radial direction of the rotary shaft. The pressed portion of the oscillator is plastically deformed, and thereby the oscillator 1 and the rotary shaft 3 are fixed. At this time, a large pressing force P also acts on the rotating shaft 3 in the radial direction, so that the rotating shaft 3 may be deformed such as broken. When the rotating shaft 3 is deformed such as broken, normal operation cannot be performed when the motor is rotating, and defects frequently occur.

In the fixing method as shown in FIG. 9, the larger the dimensional difference between the hole diameter of the hole 2 and the diameter of the rotary shaft 3, the larger the pressing force required for causing a large amount of plastic deformation during fixing. become. Therefore, the above-mentioned problem, that is, the risk that the rotary shaft 3 is deformed, such as broken, increases. In order to avoid this problem, the clearance between the rotary shaft 3 and the vibrator 1 must be reduced and maintained accurately. For example, if the diameter of the rotary shaft 3 is 1 mm, the dimensional difference between the diameter of the rotary shaft 3 and the hole diameter of the hole 2 of the vibrator 1 must be 0.04 mm or less. In order to satisfy this requirement, when forming the hole 2 in the vibrator 1,
Precise machining is required. This leads to an increase in manufacturing cost.

When the pressure applied from the radial direction of the rotary shaft 3 is constant, the caulking strength due to plastic deformation is greatly influenced by the dimensional difference between the diameter of the rotary shaft 3 and the hole diameter of the hole 2. The larger the dimensional difference, the sharper the caulking strength and the lower the fixing strength.

Japanese Unexamined Patent Publication No. 6-98496 also discloses a device in which a vibrator and a rotary shaft are fixed by welding. When welding is used as the fixing method, there are problems that the bonding strength varies greatly due to dirt on the bonding interface and the manufacturing cost rises.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is to have a high bonding strength between a rotary shaft and a vibrator and to prevent the rotary shaft from being broken. An object of the present invention is to provide a vibration generator that does not cause deformation.

Another object of the present invention is to provide a vibration generator having a low manufacturing cost.

Still another object of the present invention is to fix a vibrator that can firmly bond the rotary shaft and the vibrator with a relatively small pressure without causing fatal damage to the rotary shaft. Is to provide a method.

[0015]

A vibration generator according to the present invention has a rotary shaft which is rotationally driven by a drive source and a rotary bearing insertion hole at an eccentric position.
A vibrator fixedly held by the rotary shaft inserted in the hole is provided. The oscillator includes a central region that surrounds the hole and is located at the center when viewed in the axial direction of the rotation shaft, and end regions located at both ends. The end region has a thin portion in which the radial thickness of the rotating shaft is smaller than that of the central region. The vibrator is fixed to the rotating shaft by plastically deforming the thin portion so as to be pressed against the outer surface of the rotating shaft.

In the above-mentioned vibration generator, the rotary shaft and the vibrator are fixed by plastically deforming the thin portion. Since a large amount of pressure is not required to plastically deform the thin portion, there is little risk of deformation such as bending of the rotating shaft. Since the plastic deformation amount of the thin portion can be increased even with a smaller pressure, the joint strength between the rotary shaft and the vibrator can be increased.

In one embodiment, the thin-walled portion is a tubular body extending so as to surround the entire circumference of the hole. This cylindrical body is preferably plastically deformed so as to come into pressure contact with the outer surface of the rotary shaft at a plurality of positions that are equiangularly located on the same circumference.

In another embodiment, the thin portion is formed by forming a groove on the end face of the vibrator and at a position close to the hole. This groove is preferably formed at a plurality of positions equiangularly located on the same circumference.

In still another embodiment, the thin wall portion is a wall extending from the end face of the vibrator in the axial direction of the rotary shaft.
This wall is preferably formed at a plurality of positions equiangularly located on the same circumference.

In the method of fixing the vibrator of the vibration generator according to the present invention, first, the diameter of the rotary shaft is larger than that of the other area on the end face portion of the vibrator located at the end in the axial direction of the rotary shaft. A thin portion having a reduced thickness in the direction is formed. Next, the pressing die is moved along the axial direction of the rotating shaft to press the thin portion, whereby the thin portion is plastically deformed so as to be pressed against the outer surface of the rotating shaft.

In a preferred embodiment, the pressurizing mold plastically deforms the thin portion at a plurality of positions equiangularly located on the same circumference. Further, in one embodiment, the thin portion is a cylindrical body that extends so as to surround the entire circumference of the hole, and the pressurizing mold is
The entire circumference of the cylinder is plastically deformed so as to reduce its diameter.

In the fixing method described above, the thin portion is plastically deformed by moving the pressing die along the axial direction of the rotating shaft to press the thin portion. A large pressing force is not required to plastically deform the thin portion, and since the moving direction of the mold is along the axial direction of the rotating shaft, a large pressing force is not applied to the rotating shaft. Therefore, compared with the conventional fixing method that applies a pressing force from the radial direction of the rotating shaft,
The possibility that the rotary shaft will be deformed during the fixing work is small, and the yield is greatly improved.

Particularly, if the thin-walled portion is plastically deformed at a plurality of positions that are equiangularly located on the same circumference, a balanced force is applied to the rotary shaft, so that the rotary shaft is prevented from being deformed. be able to. The same applies to the case where the thin-walled portion is formed into a tubular body and plastically deformed so that the entire circumference of the tubular body is reduced.

In the conventional method in which a pressing force is applied and fixed by moving the pressurizing die from the radial direction of the rotary shaft, a force is applied from a specific direction to the rotary shaft, so that the rotary shaft is rotated. The shaft is easily deformed. In order to prevent such deformation, the diameter of the rotary shaft is conventionally 1
In the case of about mm, the clearance between the rotary shaft diameter and the vibrator mounting hole diameter had to be 0.04 mm or less. Therefore, it is necessary to suppress the variation in the mounting hole diameter of the vibrator in the axial direction within the clearance range.

When the material of the vibrator is a sintered body such as a tungsten-based sintered alloy and its sintering shrinkage is large, it is difficult to maintain the above-mentioned clearance. That is, if the mounting hole is used as it is as a sintered material, the inner diameter may vary due to sintering deformation or the like, and the clearance may partially exceed the upper limit. On the contrary,
Negative clearance may occur in part of the inner diameter. When the variation exceeds the upper limit of the clearance, the vibrator is discarded as a defective product. On the other hand, in the case of a mounting hole that causes a negative clearance, it is necessary to perform additional processing.

As described above, the conventional fixing method has various problems. On the other hand, according to the method of the present invention, when the diameter of the rotating shaft is about 1 mm, even if the upper limit of the clearance is increased to about 0.06 mm, the shaft is not deformed after being fixed under pressure, and high welding is achieved. A strong product is obtained. Therefore, even if a sintered body is used as the vibrator and the mounting hole is used as it is as a sintered material, the mounting hole of the vibrator is not defective, and no additional processing is required. Also in this respect, the manufacturing cost can be significantly reduced by the method of the present invention.

Further, in the method of the present invention, since the thin portion is plastically deformed, high joint strength can be maintained even if the dimensional difference between the diameter of the rotating shaft and the diameter of the mounting hole becomes large. You can This joining strength is further improved by plastically deforming the thin wall portion at a plurality of locations that are equiangular on the same circumference.

Compared with welding by welding as disclosed in Japanese Patent Laid-Open No. 6-98496, the present invention does not have a factor for deteriorating the stability of the welding strength such as dirt on the welding surface or variations in welding conditions. Therefore, stable bonding strength can be obtained, and the manufacturing cost can be significantly reduced. Regarding the material of the vibrator, a tungsten-based sintered alloy, which is a high-specific heavy alloy, is generally used for the purpose of obtaining a vibration generator that is small and has a large vibration amount. However, similar effects can be obtained if the material is plastically deformable, such as brass.

The fixing structure and the fixing method according to the present invention can be applied to other than the pager. For example,
It can also be used when joining a rotating object such as a pendulum to a rotating shaft.

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS.

The vibrator 12 has a hole 13 for inserting a rotary bearing at an eccentric position. A rotary shaft 11 that is driven to rotate by a motor 10 as a drive source has a hole 1 of a vibrator 12.
It is inserted in 3. FIG. 2 shows a state before the oscillator 12 and the rotary shaft 11 are fixed, and FIGS. 1 and 3 show a state after the both are fixed.

As shown in the figure, the vibrator 12 includes a central region that surrounds the hole 13 and is located at the center when viewed in the axial direction of the rotating shaft 11, and end regions located at both ends. The end region has a thin portion in which the radial thickness of the rotating shaft 11 is smaller than that of the central region. In this embodiment, the thin portion has cylindrical bodies 14 and 15 extending so as to surround the entire circumference of the hole 13.
Is. In order to form the cylinders 14 and 15, grooves 16 and 17 are formed on both end surfaces of the vibrator 12.

As the material of the vibrator 12, for example, a tungsten-based sintered alloy is adopted. As shown in FIGS. 1 and 3, the cylindrical body 14 that is a thin portion is
By being plastically deformed so as to come into pressure contact with the outer surface of
The vibrator 12 is fixed to the rotating shaft 11.

With reference to FIG. 2, the plastic deformation of the cylinders 14 and 15 is performed as follows. Two molds 18a are used for plastically deforming the one cylinder 14. In addition, two molds 18b are used to plastically deform the other cylinder 15. The pair of molds 18a has a rotary shaft 1
They are placed equiangularly on the same circumference around 1. Similarly, the pair of molds 18b is also placed so as to be equiangularly located on the same circumference around the rotation axis 11. Each mold 1
The tips of 8a and 18b are tapered. Further, the thickness of each mold is made larger than the width a of the grooves 16 and 17 formed on the end surface of the vibrator 12.

From the state shown in FIG. 2, each die 18a, 18
b is moved along the axial direction of the rotating shaft 11. That is, by moving the pair of molds 18a in the directions indicated by the arrows F1 and F2 and moving the pair of molds 18b in the directions indicated by the arrows F3 and F4 to press the tips of the cylinders 14 and 15. , The cylindrical bodies 14 and 15 are plastically deformed so as to come into pressure contact with the outer surface of the rotating shaft 11. Thus, finally, as shown in FIG. 3, the vibrator 12 and the rotary shaft 11 are firmly contacted and fixed by the plastically deformed pressure contact portion C.

According to the fixing structure and the fixing method as described above, the vibrator 12 and the rotary shaft 11 can be firmly bonded and fixed without causing fatal damage to the rotary shaft 11. Since the cylinders 14 and 15 are thin, it is not necessary to apply a large pressure to plastically deform the cylinders. Further, the pressing dies 18a and 18b both move along the axial direction of the rotary shaft 11, and do not apply a large pressure force to the rotary shaft 11 in the radial direction. Moreover, the pair of molds 18a,
Since all of 18b are equiangularly arranged on the same circumference surrounding the rotary shaft 11, the forces acting on the rotary shaft 11 cancel each other out. Also in this respect, damage to the rotary shaft is prevented as much as possible. In addition, since the thin cylinders 14 and 15 can generate a large amount of plastic deformation by a small pressing force, the vibrator 12 and the rotary shaft 1 can be made.
It is possible to increase the bonding strength with the No. 1 element.

The inventor of the present application conducted a comparative experiment on the joint pull-out strength. When the rotating shaft of the motor and the vibrator were fixed according to the fixing structure and fixing method disclosed in Japanese Utility Model Publication No. 4-13860, the relationship between the joint pull-out strength and the clearance was examined. When the clearance between the hole of the vibrator and the rotary shaft was 0.04 mm, the bond pull-out strength was 15 kgf. However, when the clearance was 0.06 mm, the joint pull-out strength was 5 kgf, and it was confirmed that the joint pull-out strength was significantly reduced as the dimensional difference increased. Further, when the fixing work was performed according to the structure and method disclosed in Japanese Utility Model Publication No. 4-13860, the rotation shaft was deformed.

According to the joining structure and joining method shown in FIGS. 1 to 3, the vibrator and the rotary shaft were joined and fixed, and the relationship between the joint pull-out strength and the clearance was also examined. In this case, the joint pull-out strength is 20 kgf both when the clearance is 0.04 mm and when the clearance is 0.06 mm.
Did not change. In addition, no deformation was found on the rotating shaft.

The joint pull-out strength test was carried out by the method shown in FIG. The rotary shaft 11 and the hole 21 of the wall surface 20 are aligned, and a force indicated by G is applied to the rotary shaft 11.
The pull-out strength of the rotary shaft 11 in this case was measured.

The embodiments shown in FIGS. 1 to 3 are merely examples of the present invention. Various modifications and variations are possible.
For example, in the embodiment shown in FIGS.
Was plastically deformed at two positions that are equiangularly located on the same circumference, but may be plastically deformed so that the entire circumferences of the cylinders 14 and 15 are reduced in diameter. In this case, as a mold for plastically deforming the cylinders 14 and 15, one mold having a central hole and a tapered opening end can be used instead of the two molds.

In the embodiment shown in FIGS. 1 to 3, the vibrator 1
Both of the cylinders 14 and 15 located at both ends of 2 were plastically deformed. However, only one cylinder may be plastically deformed. The method in that case is shown in FIG. In order to plastically deform one cylinder 14 as shown in FIG.
A pair of molds 18 is used. Since it is not necessary to plastically deform the other cylinder 15, the other end surface of the vibrator 12 is
A pressing plate 19 for supporting the pressing force from the mold 18 is arranged. In the case of this embodiment, since the other cylinder 15 is not plastically deformed, it is not necessary to provide this cylinder 15.

In the above-described embodiments, the thin wall portion is a cylindrical body extending so as to surround the entire circumference of the hole. Another example of forming such a cylinder is shown in FIG. The groove 3 surrounding the rotary shaft 31 is provided on the end face of the vibrator 32 which receives the rotary shaft 31.
3 is formed. By forming the groove 33, a thin cylindrical body 34 is formed. As another example, it may be possible to form the groove 33. In this case, the cylindrical body 34 may be formed so as to extend in the axial direction of the rotating shaft 31 from the end surface of the vibrator 32.

In the embodiment shown in FIG. 7, the thin portions 45 and 46 are formed by forming two grooves 43 and 44 on the end face of the vibrator 42 which receives the rotary shaft 41.
Desirably, the grooves 43 and 44 are provided so as to be equiangularly located on the same circumference surrounding the rotary shaft 41. Although two grooves are provided in the illustrated embodiment, three grooves or four grooves may be provided.

As another embodiment, the thin portion may be formed by providing a plurality of walls extending from the end surface of the vibrator in the axial direction of the rotary shaft. Even in this case,
The walls are preferably equiangularly located on the same circumference.

As described above, according to the present invention, the thin portion is plastically deformed so as to be pressed against the outer surface of the rotary shaft to fix the vibrator to the rotary shaft. The rotary shaft and the vibrator can be firmly joined to each other without causing such deformation.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view of an embodiment of the present invention before joining and fixing.

FIG. 3 is a cross-sectional view of one embodiment of the present invention after joining and fixing.

FIG. 4 is a cross-sectional view showing another example of a fixing method.

FIG. 5 is a diagram showing a method for investigating the bond pull-out strength.

FIG. 6 is a side view showing another embodiment of the present invention.

FIG. 7 is a side view showing still another embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a state before fixing of a conventional bonded structure of a vibrator and a rotary shaft.

FIG. 9 is a cross-sectional view showing a conventional joining structure after joining.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 motor 11 rotating shaft 12 vibrator 13 hole 14 and 15 cylindrical body 16 and 17 groove 18a and 18b mold

Claims (10)

[Claims] 1. A rotary shaft, which is driven to rotate by a drive source, and a vibrator which has an opening for inserting the rotary bearing at an eccentric position and which is fixedly held by the rotary shaft inserted into the hole. In the vibration generating device, the vibrator includes a central region that surrounds the hole and is located at the center when viewed in the axial direction of the rotating shaft, and end regions located at both ends, and the end region is Compared to the central region, the rotary shaft has a thin portion in which a radial thickness of the rotary shaft is reduced, and the thin wall portion is plastically deformed so as to be in pressure contact with an outer surface of the rotary shaft, so that the rotary shaft A vibration generator, wherein the vibrator is fixed. 2. The vibration generator according to claim 1, wherein the thin portion is a cylindrical body extending so as to surround the entire circumference of the hole. 3. The vibration generator according to claim 2, wherein the cylindrical body is plastically deformed at a plurality of positions that are equiangularly located on the same circumference so as to come into pressure contact with the outer surface of the rotating shaft. . 4. The vibration generator according to claim 1, wherein the thin portion is formed by forming a groove at a position on the end face of the vibrator and close to the hole. 5. The vibration generator according to claim 4, wherein the groove is formed at a plurality of positions that are equiangularly located on the same circumference. 6. The thin portion is a wall extending from the end face of the vibrator so as to project in the axial direction of the rotating shaft.
The vibration generator described in 1. 7. The vibration generator according to claim 6, wherein the walls are formed at a plurality of positions that are equiangularly located on the same circumference. 8. A method for fixing a vibrator having a hole for inserting a rotary bearing at an eccentric position to a rotary shaft, the vibrator being located at an end of the rotary shaft when viewed in the axial direction. A thin-walled portion having a smaller radial thickness of the rotary shaft than the other region is formed on the end face portion, and the pressing die is moved along the axial direction of the rotary shaft to press the thin-walled portion. The method of fixing a vibrator of a vibration generator, wherein the thin portion is plastically deformed so as to be pressed against the outer surface of the rotating shaft. 9. The pressurizing die plastically deforms the thin portion at a plurality of positions which are equiangularly located on the same circumference.
A method for fixing a vibrator of a vibration generator according to claim 8. 10. The thin portion is a tubular body extending so as to surround the entire circumference of the hole, and the pressing die plastically deforms so as to reduce the entire circumference of the tubular body. Item 9. A method for fixing a vibrator of a vibration generator according to Item 8.