JPH11117996A - Damper and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve environment of a manufacturing field for a damper and to reduce a manufacturing cost. SOLUTION: A collar 24 made of rigid resin is fitted in the outer peripheral part of a hub 16 fixed on a shaft 14 and a collar 30 made of rigid resin is fitted in the inner peripheral part of a ring 26 being a mass body. An elastic body 32 made of soft resin to intercouple the collars 24 and 30 is thermally fused to the collars 24 and 30. As noted above, shear deformation in a twist direction is effected and the elastic body 32 to absorb vibration of the shaft 14 is securely adhered to the hub 16 and the ring 26 through thermal fusion without using a adhesive. Thereby, environment of a manufacturing field is not polluted by toluene. Further, since there is no need for management of the thickness of an adhesive and a drying process, a manufacturing cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damper fixed to a motor shaft and absorbing vibration.

[0002]

2. Description of the Related Art As shown in FIG. 7, a damper 50 for absorbing vibration is attached to a shaft of a stepping motor arranged in a paper feeding section of a copying machine. The damper 50 includes a brass hub 54 fixed to a shaft 52, a vibration ring 56 as a mass body, and a hub 5.
4 and a rubber elastic body 58 connecting the vibration ring 56. The vibration of the shaft 52 is absorbed by the shearing resistance in the torsion direction of the elastic body 58 due to the relative displacement between the hub 54 and the vibration ring 56.

In the current damper 50, an adhesive (containing toluene) is applied to the outer peripheral surface of the hub 54 and the inner peripheral surface of the vibrating ring 56 and dried to use the residual heat generated when the elastic body 58 is formed. The hub 54 and the vibrating ring 56
In this case, a manufacturing method of bonding the elastic member 58 to the elastic member 58 is adopted.

[0004] However, toluene contained in the adhesive pollutes the environment of the manufacturing site. In addition, in order to stabilize the adhesive strength, it is necessary to control the thickness of the adhesive, and furthermore, the drying step of the adhesive is also an indispensable condition.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the environment of a manufacturing site and reduce manufacturing costs in view of the above fact.

[0006]

According to the first aspect of the present invention, a first hard resin portion is fitted to an outer peripheral portion of a hub fixed to a shaft, and a second hard resin portion is fitted to an inner peripheral portion of a ring as a mass body. The hard resin part is fitted. An elastic body made of a soft resin connecting the first hard resin portion and the second hard resin portion is thermally fused to the first hard resin portion and the second hard resin portion.

[0007] As described above, since the elastic body that undergoes shear deformation in the torsion direction and absorbs vibration of the shaft is fixed between the hub and the ring by heat fusion without using an adhesive, toluene or the like is used. Therefore, the environment of the manufacturing site is not polluted. In addition, since there is no need to control the thickness of the adhesive and to perform a drying step, the manufacturing cost can be reduced.

According to the second aspect of the present invention, the outer peripheral surface of the hub is knurled, so that the pull-out strength of the first hard resin portion and the displacement strength in the rotational direction are improved. Further, by applying a pressure to wind the first hard resin portion, the inner peripheral wall of the first hard resin portion bites into the knurled portion, and the pull-out strength and the displacement strength are further improved.

According to a third aspect of the present invention, in a separate step, the first hard resin portion is fitted to the outer peripheral portion of the hub, and the second hard resin portion is fitted to the inner peripheral portion of the ring. Next, the hub and the ring are inserted into a mold so that they are concentric, and a soft resin material is injected into a ring-shaped cavity formed by the first hard resin portion and the second hard resin portion.

As described above, by using insert molding, an elastic body made of a soft resin connecting the ring and the hub can be easily molded without polluting the environment of the manufacturing site. In addition, the injection pressure of the soft resin
Since the hard resin portion is pressed against the hub, if the outer peripheral surface of the hub is knurled, the pullout strength and the displacement strength are improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, a damper 10 according to the present embodiment includes a hub 16 fixed to a shaft 14 of a stepping motor 12. The hub 16 is made of brass and is formed in a cylindrical shape, and a screw hole 20 is formed on a side surface of the hub 16 at a position corresponding to the D-cut portion 18 formed on the shaft 14. Also, a screw hole 22 is formed in the flat surface of the D-cut portion 18 as well,
Screws (not shown) are screwed into the screw holes 20 and 22, and the hub 1
6 is fixed to the shaft 14.

The outer peripheral surface of the hub 16 is knurled (ex. Iris knurl) with knurls having sharp triangular teeth. A cylindrical hard resin (ex.polypropylene) collar 24 is press-fitted into the outer peripheral surface by ultrasonic waves or while the hub 16 is heated. Further, a rib 24A is formed on the outer peripheral portion of the collar 24 along the circumferential direction, and is devised so that an elastic body 26 described later is easily fixed.

On the other hand, a ring 26 as a mass body is disposed on the outer peripheral portion of the hub 16. On the upper surface of the ring 26,
A plurality of mounting holes 28 are formed along the circumferential direction. A connecting leg 32 hanging from a collar 30 made of a hard resin and having a ring shape is inserted into the mounting hole 28.
When the connecting leg 32 is inserted into the mounting hole 28, the distal end is thermally caulked, and the collar 30 and the ring 26 are integrated (see FIG. 5).

Further, as shown in FIG.
The cross section is L-shaped, and the vertical portion 30A is the ring 2
6 is in contact with the inner peripheral wall. This vertical 30A and ring 2
The horizontal portion 30 </ b> B is in close contact with the upper surface of the ring 26 so as to surround the inner peripheral corner of the ring 6. The annular groove 30C formed in the horizontal portion 30B prevents the collar 30 from being distorted due to heat.

Further, between the collar 24 and the collar 30, a ring-shaped elastic body 3 made of soft resin (ex. TPE) is provided.
2 is heat-sealed. An annular concave portion 32A is formed on the upper and lower surfaces of the elastic body 32.
By changing the size of A, the spring constant can be adjusted.

Next, a method of manufacturing the damper according to the present embodiment will be described. First, as shown in FIG.
The hub 16 fitted with 4 and the ring 26 fitted with the collar 30 are manufactured in separate processes.

Next, as shown in FIG. 4, the hub 16 and the ring 26 are inserted into the mold 36 so as to be concentric. A concave portion for holding the hub 16 and the ring 26 is formed on the cavity surface of the mold 36. With the hub 16 and the ring 26 inserted, the collar 2
A cavity 38 in which the elastic body 32 (see FIG. 5) is formed is formed between the collar 4 and the collar 30.

A soft resin material is injected from the gate 40 into the cavity 38. At the injection pressure at this time, the color 24
Is pressed against the hub 16, the inner peripheral wall of the collar 24 bites into the knurled portion, and the pull-out strength and displacement strength of the collar 24 are improved. This is shown in FIG.
When the collar 24 is peeled from the hub 16, the collar 24
It can also be seen from the fact that the shape of the knurl is transferred to the inner peripheral surface of.

As described above, by using the insert molding, the elastic body 32 is fixed to the ring 26 and the hub 16 by heat fusion, so that the environment of the manufacturing site is not polluted by toluene or the like. In addition, since there is no need to control the thickness of the adhesive and to perform a drying step, the manufacturing cost can be reduced.

The material of the ring 26 is not limited as long as it has a predetermined mass. The hub 16 does not need to be made of brass, and may be formed of a hard resin material.

[0021]

According to the present invention, the elastic member is fixed between the hub and the ring by heat fusion without using an adhesive. Therefore, the environment of the production site is not polluted by toluene or the like, and the thickness control and drying process of the adhesive are not required, so that the production cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a relationship between a damper according to the present embodiment and a motor shaft.

FIG. 2 is an exploded perspective view before an elastic body is thermally fused to the damper according to the embodiment.

FIG. 3 is a perspective view showing a positional relationship between a hub and a ring of the damper according to the present embodiment.

FIG. 4 is a cross-sectional view showing a state where a hub and a ring of the damper according to the present embodiment are inserted into a mold.

FIG. 5 is a sectional view of a damper according to the embodiment.

FIG. 6 is a perspective view showing an inner peripheral surface of a collar of the damper according to the embodiment.

FIG. 7 is a sectional view showing a conventional damper.

[Explanation of symbols]

 16 Hub 24 Collar (first hard resin portion) 26 Ring 30 Collar (second hard resin portion) 32 Elastic body

Claims (3)

[Claims] 1. A damper fixed to a shaft of a motor and absorbing vibration, a hub fixed to the shaft, a first hard resin portion fitted to an outer peripheral portion of the hub, and a ring as a mass body. A second hard resin portion fitted to an inner peripheral portion of the ring, and a first hard resin portion and a second hard resin portion thermally fused to the first hard resin portion and the second hard resin portion. And an elastic body made of a soft resin connecting the elastic members. 2. The outer peripheral surface of the hub is knurled,
The damper according to claim 1, wherein a pressure for winding the first hard resin portion is applied. 3. A method of manufacturing a damper fixed to a shaft of a motor and absorbing vibration, wherein a step of fitting a first hard resin portion to an outer peripheral portion of a hub fixed to the shaft; A step of fitting a second hard resin portion to an inner peripheral portion, and inserting the hub and the ring into a mold such that the hub and the ring are concentric;
Injecting a soft resin material into a ring-shaped cavity formed by the first hard resin portion and the second hard resin portion;
A method for manufacturing a damper, comprising: