JPH08177980A - Torsional damper and its manufacture - Google Patents

Abstract

PURPOSE: To improve accuracy in the outer peripheral surface of a damper mass simply for preventing a belt from slipping by forming a portion of the damper mass including the outer peripheral surface around which the belt for transmitting the power is wrapped, out of a synthetic resin material. CONSTITUTION: A cylindrical damper mass 6 having the outer peripheral surface wrapped around by a power transmitting belt is mounted on the radially outer side of a cylindrical part 2 of a pulley body 10 through a sleeve 4 and elastic body 5 to be positioned concentrically with the cylindrical part 2. The damper mass 6 has a groove part 6A and mountain part 6B on the outer peripheral surface and the part including the outer peripheral surface of the damper mass 6 is formed of synthetic resin material. Then, the outer peripheral surface having the high accuracy dimension is obtained by a few processes and the belt is accurately fitted in the high accuracy groove part and mounting part to prevent the slip. Thus, the outer peripheral surface is shaped with high accuracy to reduce cost without needing any machining.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torsional damper mounted on a rotary shaft such as a crankshaft of an automobile engine so as to absorb vibrations in the torsional direction of the rotary shaft, and a method for manufacturing the same.

[0002]

2. Description of the Related Art This type of torsional damper comprises a boss attached to a rotary shaft, a cylindrical cylindrical portion located radially outside the boss, and a connecting portion connecting the cylindrical portion and the boss. It is known that a damper mass, which has a cylindrical shape with a sleeve and an elastic body and is wound around the outer peripheral surface of a cylindrical portion of a cylindrical portion of a pulley main body, around which a power transmission belt is wound is attached so as to be concentric with the cylindrical portion. ing.
The entire body except the elastic body is made of a metallic material such as cast iron. The elastic body adhered to the sleeve and the damper mass was pressed into the cylindrical portion.

[0003]

In order to prevent the power transmission belt wound around the outer peripheral surface of the metallic damper mass from slipping, high precision is required for the dimensions of the groove portion and the mountain portion on the outer peripheral surface. As a result, the number of machining steps required for machining the groove and the peak increases, resulting in an increase in cost.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a torsional damper in which the accuracy of the outer peripheral surface of the damper mass is easily improved and a belt slip is prevented, and a manufacturing method thereof.

[0005]

In order to achieve the above-mentioned object, the present invention is one in which a portion including an outer peripheral surface around which a power transmission belt of a damper mass is wound is formed of a synthetic resin material.

[0006]

Since the outer peripheral surface of the damper mass is formed of a synthetic resin material, it is possible to easily realize a highly accurate outer peripheral surface shape without the need for machining and to reduce the cost.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

In the first embodiment shown in FIG. 1, a boss 1 attached to a rotating shaft (not shown), a cylindrical cylindrical portion 2 located radially outside the boss 1, a cylindrical portion 2 and the boss 1. A power transmission belt (not shown) having a cylindrical outer peripheral surface with a sleeve 4 and an elastic body 5 on the outer side in the radial direction of the cylindrical portion 2 of the pulley body 10 including a connecting portion 3 for connecting the
A damper mass 6 around which is wound is attached so as to be concentric with the cylindrical portion 2. The outer peripheral surface of the damper mass 6 has a groove portion 6A and a mountain portion 6B, and a portion including the outer peripheral surface of the damper mass 6 is formed of a synthetic resin material.

In the second embodiment shown in FIG. 2, the outer peripheral surface of the damper mass 6 is made of a synthetic resin material in the same manner as in the first embodiment. There are many.

The embodiment shown in FIG. 3 shows that the shape of the pulley body 10 is changed and the shapes of the groove portion 6A and the peak portion 6B of the damper mass 6 are changed, and the portion including the outer peripheral surface of the damper mass 6 is made of synthetic resin. It is made of material.

In the fourth embodiment shown in FIG. 4, the portion including the outer peripheral surface of the damper mass 6 is formed of a synthetic resin material, and the synthetic resin material portion occupies about half of the damper mass 6. This is the same as the embodiment of FIG. 2, but differs in that the cylindrical portion 2 and the connecting portion 3 are also made of a synthetic resin material. Further, in the fourth embodiment, since the cylindrical portion 2 and the connecting portion 3 are integrally molded with the synthetic resin material, the metal sleeve 4 which is conventionally required is not necessary.

The fifth embodiment shown in FIG. 5 has substantially the same construction as the third embodiment, but the cylindrical portion 2 and the connecting portion 3 are integrally molded with a synthetic resin material. Also in this embodiment. The metal sleeve 4 becomes unnecessary.

In the fourth and fifth embodiments, the sleeve 4 is not required, and the cost can be reduced accordingly. Further, the work of press-fitting the sleeve 4 into the cylindrical portion 2 is also unnecessary. Further, since the cylindrical portion 2 and the connecting portion 3 are integrally molded with a synthetic resin material, the weight of the entire body is reduced. When the weight of the whole is large, when it is attached to the crankshaft of the engine, it rotates at high speed together with the crankshaft, so it is desirable to reduce the weight in terms of energy and reactivity. In addition, the rotary shaft such as the crankshaft,
Usually, not only the vibration in the torsional direction but also the vibration in the bending direction (the direction perpendicular to the axis) can be generated at the same time. Therefore, by mounting such a damper on such a rotating shaft, the weight of the rotating portion is greatly increased. Therefore, the deflection of the rotary shaft in the direction perpendicular to the axis is increased, and therefore, in the rotary shaft and the engine, the vibration caused by the vibration in the bending direction of the rotary shaft,
Although there was a problem that the noise was significantly increased, the problem is solved by reducing the weight.

FIG. 6 shows an example of a method of molding the synthetic resin material portion of the fifth embodiment shown in FIG. 5, in which a boss 1, an elastic body 5 and a damper mass 6 are set in a molding die 20. A cavity 2 for molding the cylindrical portion 2 and the connecting portion 3 formed in the molding die 20 and a cavity 2 for molding a part including the outer peripheral surface of the damper mass 6.
A synthetic resin material is injected into each of the two. Cavity 21,
A synthetic resin material is injected into the inside 22, and after the synthetic resin material is cooled and solidified, the molding die 20 is opened to open the cylindrical portion 2, the elastic body 5, the connecting portion 3 and the boss 1, the damper mass 6 and the outer peripheral surface thereof. Take out the product that is integrated with the parts that compose the. In FIG. 6, reference numerals 23 and 24 denote gates, and the molding die 20 is composed of an upper die and a lower die. The elastic body 5 and the damper mass 6 may be vulcanized and bonded in advance, and the integrated body may be set in the molding die 20. Alternatively, the elastic body 5 and the elastic body 5 may be bonded to each other without being bonded. The elastic body 5 may be adhered to the damper mass 6 at the time of molding the synthetic resin material by subjecting one surface to an adhesive treatment with, for example, an epoxy adhesive. Furthermore,
The surface of the elastic body 5 that contacts the synthetic resin material may be preliminarily subjected to the same adhesion treatment as described above. When the synthetic resin material is cooled and solidified in the cavities 21 and 22, each of the boss 1, the elastic body 5, and the damper mass 6 and the synthetic resin material are fixed to each other. By forming a ridge or a protrusion on the surface of the boss 1 that comes into contact with the synthetic resin material, the boss 1 and the connecting portion 3 formed of the synthetic resin material are more firmly fixed to each other. .

In each of the embodiments shown in FIGS. 1 to 3, a molding die 20 in which the cavity 21 and the gate 23 are not present and only the gate 24 and the cavity 22 are formed is used. Then, a part including the outer peripheral surface of the damper mass 6 may be molded in the cavity 22. That is, first, the damper mass 6 and the cylindrical portion 2 are vulcanized and adhered to both surfaces of the elastic body 5 (only one of the damper mass 6 and the cylindrical portion 2 may be vulcanized and adhered), or both surfaces of the elastic body 5 (vulcanized and adhered). Adhesive treatment may be applied to one side that does not adhere to sulfur. Next, the pulley body 1
0, the elastic body 5, and the damper mass 6 are set at predetermined positions in the molding die 20. Then, a synthetic resin material is injected from the gate 24 into the cavity 22 to mold a portion including the outer peripheral surface of the damper mass 6 (a portion including the groove portion 6A and the mountain portion 6B in FIGS. 1 to 3), and after cooling and solidification, the whole body is formed. Take out the integrated one. The molding of the part including the outer peripheral surface and the step of integrating the whole are performed simultaneously.

In the sixth embodiment shown in FIG. 7, the cylindrical portion 2 and the connecting portion 3 are molded with a synthetic resin material, and the groove portion 2A and the ridge portion 2B are formed on a part of the outer peripheral surface of the cylindrical portion 2 to form a damper. The belt 6 is formed in cooperation with the groove portion 6A and the mountain portion 6B of the mass 6.

In any of the embodiments described above,
The damper mass 6 needs to be heavy in order to exert the function of the dynamic damper. Therefore,
The synthetic resin material portion of the damper mass 6 includes the groove portion 6A and the mountain portion 6
Only the surface portion of B or the vicinity thereof. Further, by forming fine irregularities on the outer peripheral surface of the damper mass 6 made of a synthetic resin material, the belt slip can be further prevented. The unevenness can be easily formed by processing the surface of the molding die 20.
It is possible to make the outer peripheral surface of the sparse.

[0018]

As described above, according to the present invention, since the portion including the outer peripheral surface around which the power transmission belt of the damper mass is wound is formed of the synthetic resin material, the number of man-hours is high and the dimension is high. The shape of the outer peripheral surface is obtained, and the belt is accurately fitted in such highly accurate grooves and ridges, and slip is prevented. Further, since the outer peripheral surface of the damper mass is formed by injection molding means instead of machining as in the conventional case, manufacturing is facilitated and cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment.

FIG. 2 is a sectional view showing a second embodiment.

FIG. 3 is a sectional view showing a third embodiment.

FIG. 4 is a sectional view showing a fourth embodiment.

FIG. 5 is a sectional view showing a fifth embodiment.

FIG. 6 is a cross-sectional view showing an example of means for molding a resin portion of a torsional damper according to a fifth embodiment.

FIG. 7 is a sectional view showing a sixth embodiment.

[Explanation of symbols]

 1 Boss 2 Cylindrical part 3 Connection part 5 Elastic body 6 Damper mass 10 Pulley body 20 Mold

Claims (4)

[Claims] 1. A radius of the cylindrical portion of the pulley main body, which comprises a boss attached to the rotary shaft, a cylindrical cylindrical portion located outside of the boss in the radial direction, and a connecting portion connecting the cylindrical portion and the boss. In a torsional damper in which a damper mass, which is cylindrical and has a power transmission belt wound around the outer peripheral surface through an elastic body, is installed so as to be concentric with the cylindrical portion, the power transmission belt of the damper mass is wound. A torsion damper characterized in that a portion including an outer peripheral surface to be hung is formed of a synthetic resin material. 2. The torsion damper according to claim 1, wherein the damper mass made of a synthetic resin material has irregularities formed on the outer peripheral surface. 3. The torsion damper according to claim 1, wherein the cylindrical portion and the connecting portion are integrally molded of a synthetic resin material. 4. The radius of the cylindrical portion of the pulley body, which comprises a boss attached to the rotating shaft, a cylindrical cylindrical portion located radially outside of the boss, and a connecting portion connecting the cylindrical portion and the boss. In the method of manufacturing a torsion damper in which a damper mass, which is cylindrical through an elastic body on the outer side in the direction and on which the power transmission belt is wound, is attached so as to be concentric with the cylindrical portion, The process of vulcanizing and bonding the cylindrical part to both sides of the elastic body, the step of setting the pulley body, the elastic body and the damper mass in the injection mold, and the injection of the synthetic resin material into the mold. A step of molding a portion including the outer peripheral surface of the damper mass, and a step of integrating the pulley main body, the elastic body, the damper mass and the portion including the outer peripheral surface thereof after the synthetic resin material is cooled and solidified. Method for producing a torsional damper, characterized by comprising al.