JP7542479B2 - Torsional Damper - Google Patents

Description

The present invention relates to a torsional damper.

A torsional damper (hereafter referred to as TVD) is a product that is attached to the end of the crankshaft and has the function of reducing the torsional vibration of the crankshaft by the action of a rubber ring that fits between the hub and the vibration ring (mass). In some cases, TVDs also function as a crank pulley that transmits power to auxiliary equipment (alternator, air conditioner, water pump, etc.) via a belt.

Several TVDs have been proposed to reduce bending vibrations in addition to the torsional vibrations mentioned above.

For example, Patent Document 1 describes a crank damper for a vehicle, particularly a dual mode crank damper that can effectively prevent both torsional and bending resonant vibrations of the crankshaft, in which an elastic body is provided on the outer periphery of the crankshaft of the vehicle, a first mass body is provided on the elastic body, a support arm is protruding from the first mass body, and a second mass body is provided at the tip of the support arm that is distant from the mass body in the axial direction of the crankshaft. This crank damper can effectively prevent both torsional and bending resonant vibrations of the crankshaft by appropriately tuning the natural frequencies of the torsional damper and bending damper, and is described as being easy and inexpensive to manufacture because the torsional damper and bending damper are integrated into one structure.

Patent Document 2 also describes a damper-equipped crank pulley in which a rubber-like elastic damper material is arranged in layers between the rim of the crank pulley and a ring-shaped outer peripheral mass arranged on the outside of the rim, and the center of gravity of the outer peripheral mass is arranged outside the extension direction of the crankshaft from the center position of the damper material in the rotational axis direction. It is described that such a damper pulley can suppress both the torsional vibration of the crankshaft and the bending vibration of the crankshaft end, and can effectively suppress the noise generated by these vibrations.

Patent Document 3 also describes a damper device that includes: (a) a boss attached to a rotating shaft such as a crankshaft; a cylindrical portion with low rigidity and an axial width W1 located radially outside the boss; and a connecting portion connecting the boss and the cylindrical portion; (b) a torsional vibration/flexural vibration damper mass that is concentrically arranged radially outside the cylindrical portion of the hub and has a main portion with an axial width W2 and an overhang portion with an axial width W3; and (c) an elastic body provided between the cylindrical portion of the hub and the main portion of the torsional vibration/flexural vibration damper mass, and the overhang portion of the torsional vibration/flexural vibration damper mass is provided on one end side of the cylindrical portion away from the connecting portion between the cylindrical portion of the hub and the connecting portion. The damper device described above has the effect of damping torsional vibration and bending vibration, reducing the number of parts, and making the device inexpensive.

Utility Model Publication No. 63-170632 Japanese Utility Model Application Publication No. 2-84049 Japanese Patent Application Publication No. 10-159903

However, up until now, there has been no proposal for a torsional damper that can sufficiently reduce bending vibrations in the twisting direction (twisting vibration) and that has fewer component parts than a double-mass type.

The present invention aims to solve the above problems. In other words, the present invention aims to provide a torsional damper that can sufficiently reduce torsional vibration and twisting vibration, and has fewer components than the double mass type.

The present inventors have conducted extensive research and completed the present invention.
The present invention relates to the following (1) to (3).
(1) a hub fixed to a tip of a rotating shaft and having an outer circumferential surface on a circumference centered on the rotating shaft;
an annular vibration ring having an inner circumferential surface on a circumference centered on the rotation axis, the inner circumferential surface having a larger diameter than the outer circumferential surface of the hub;
a rubber ring disposed between the outer circumferential surface of the hub and the inner circumferential surface of the vibration ring;
Equipped with
A torsional damper comprising an overhang portion that is connected to the tip side of the vibration ring in a direction parallel to the rotation axis and further extends toward the tip.
(2) the overhang portion is cylindrical and has an inner circumferential surface on a circumference centered on the rotation axis,
The torsional damper described in (1) above, wherein the radius of the inner circumferential surface is equal to or smaller than the radius of the outer circumferential surface of the hub.
(3) The torsional damper according to (1) or (2) above, wherein a pulley groove is formed on an outer peripheral surface of the overhang portion.

The present invention provides a torsional damper that can reduce torsional and twisting vibrations and has fewer components than the double-mass type.

1 is a schematic cross-sectional view illustrating an embodiment of a torsional damper of the present invention. FIG. 1 is a schematic diagram showing the layout of an apparatus that is the premise of a simulation of an effect verification test (1). These are the results of the effectiveness verification test (1). FIG. 11 is a schematic cross-sectional view illustrating a torsional damper of a comparative example in an effect verification test (2). 1 shows the results of effectiveness verification test (2) (in the case of the present invention). 1 shows the results of effect verification test (2) (comparative example).

The present invention will now be described.
The present invention is a torsional damper comprising: a hub fixed to the tip of a rotating shaft and having an outer peripheral surface on a circumference centered on the rotating shaft; an annular vibrating ring having an inner peripheral surface on a circumference centered on the rotating shaft and having a larger diameter than the outer peripheral surface of the hub; and a rubber ring located between the outer peripheral surface of the hub and the inner peripheral surface of the vibrating ring, and comprising an overhang portion connected to the tip side of the vibrating ring in a direction parallel to the rotating shaft and extending further toward the tip.
Such a torsional damper will hereinafter be referred to as the "torsional damper of the present invention."

First, the torsional damper of the present invention will be described with reference to FIG.
FIG. 1 is a schematic diagram (schematic cross-sectional view) of a cross section obtained when an embodiment of a torsional damper of the present invention is cut along a rotation axis.

The torsional damper 1 of the embodiment illustrated in FIG. 1 can be attached to the tip of the crankshaft of an engine of a vehicle or the like. The torsional damper 1 has the function of absorbing the torsional resonance and twisting resonance of the crankshaft and suppressing engine vibration and noise. In addition, it may also function as a drive pulley (crank pulley) that transmits power from the rotation of the crankshaft to an auxiliary device via a belt.

The torsional damper 1 has a hub 3, a vibration ring 5, and a rubber ring 7.

<Hub>
The hub 3 has a boss portion 31 , a stay portion 33 and a rim portion 35 .
The boss portion 31 is provided at the radial center of the hub 3. The boss portion 31 is fixed to the tip of a crankshaft (rotary shaft), and the hub 3 is driven to rotate about a rotation axis X.
The stay portion 33 extends radially from the boss portion 31 .
The rim portion 35 is provided on the outer periphery of the stay portion 33. The rim portion 35 is cylindrical, and the vibration ring 5 is connected to the outer periphery of the rim portion 35 via the rubber ring 7.
The outer peripheral surface of the rim portion 35 exists on a circumference with the rotation axis X as the center.

The boss portion 31, the stay portion 33, and the rim portion 35 can each be formed using a metallic material such as cast iron as a raw material. In addition, it is particularly preferable that the boss portion 31, the stay portion 33, and the rim portion 35 each be made of flake graphite cast iron, spheroidal graphite cast iron, hot-rolled steel plate for automobile structures, or the like.

<Vibration ring>
The vibration ring 5 is disposed radially outside the hub 3. The inner peripheral surface of the vibration ring 5 has a larger diameter than the outer peripheral surface of the hub 3. This inner peripheral surface exists on a circumference centered on the crankshaft (rotation axis X).
Further, a pulley groove 51 for a belt to be wound around is provided on the outer circumferential surface of the vibration ring 5. The pulley groove 51 functions as a pulley for transmitting power.
The torsional damper of the present invention preferably has a pulley groove on the outer circumferential surface of the vibrating ring, as in the embodiment shown in FIG.

The vibration ring 5 can be formed using a metallic material such as cast iron as a raw material.
Moreover, the vibration ring 5 is preferably made of flake graphite cast iron, because flake graphite cast iron has excellent vibration absorbing ability and excellent wear resistance.

<Overhanging part>
The torsional damper 1 includes an overhang portion 8 on the tip side (left side in FIG. 1 ) of the vibration ring 5 in a direction parallel to the rotation axis X.
The overhang portion 8 is connected to the tip side of the vibration ring 5, and extends from this tip side further in the tip direction (to the left in FIG. 1).
Torsional vibration and twisting vibration can be sufficiently reduced by providing such an overhang portion 8. In addition, since the overhang portion 8 can be molded integrally with the vibration ring 5, the number of components does not increase.
The overhang portion 8 is connected to the vibration ring 5, but in the direction parallel to the rotation axis X, the portion that is present further toward the tip side than the tip of the rubber ring 7 is defined as the overhang portion 8.

The overhang portion 8 is preferably cylindrical, as in the embodiment illustrated in FIG.
Furthermore, it is preferable that the inner circumferential surface 80 of the overhang portion 8 exists on a circumference centered on the rotation axis X, and that the radius ( _Y1 ) of the inner circumferential surface is equal to or smaller than the radius ( _Y2 ) of the outer circumferential surface of the hub 3. In other words, it is preferable that _Y1 ≦ _Y2 .
In this case, torsional vibration and prying vibration can be further reduced.
In addition, when the radius ( _Y1 ) and the radius ( _Y2 ) are specified multiple times depending on the measurement position, these values are both assumed to mean average values. The same applies to the radius of the outer peripheral surface of the overhang portion 8 and the radius of the inner peripheral surface of the vibration ring 5, which will be described later.

As shown in FIG. 1, the overhang portion 8 preferably has a pulley groove 81 on its outer circumferential surface.
The inventors have discovered that by placing a belt on the pulley groove 81 of the overhang portion 8, the rotation of the crankshaft can be transmitted to the auxiliary device via the belt, thereby making it possible to further reduce twisting vibration.

The outer peripheral surface of the overhang portion 8 on which the pulley groove 81 is formed exists on a circumference centered on the rotation axis X, and the radius of the circumference is preferably smaller than the radius of the inner peripheral surface of the vibration ring 5 .
In this case, torsional vibration and prying vibration can be further reduced.

The overhang portion 8 can be molded integrally with the vibration ring 5. Therefore, the overhang portion 8 can be formed using the same material as the vibration ring 5.

<Rubber ring>
The rubber ring 7 is inserted into the gap between the outer peripheral surface of the hub 3 and the inner peripheral surface of the vibration ring 5. The rubber ring 7 serves to reduce torsional vibration and twisting vibration of the crankshaft that occur while the vehicle is running, thereby preventing damage, and also serves to reduce noise and vibration caused by the engine.
The rubber ring is present in a radially compressed state between the outer circumferential surface of the hub and the inner circumferential surface of the vibration ring.

The rubber ring 7 can be obtained by vulcanizing a rubber composition containing ethylene-propylene-diene terpolymer (EPDM) as the main component, and preferably also carbon black and process oil, into a cylindrical shape, for example, by a conventionally known method. Specifically, for example, the rubber composition preferably contains 10 to 60 parts by mass of EPDM and 40 to 130 parts by mass of carbon black per 100 parts by mass of EPDM.

In the torsional damper of the present invention, the natural frequency in the torsional direction can be set to a predetermined value mainly by adjusting the total mass of the vibration ring and the overhanging portion and the shear spring constant of the rubber ring, while the natural frequency in the twisting direction can be set to a predetermined value mainly by adjusting the mass of the overhanging portion and the spring constant of the rubber ring when twisted.
By matching the natural frequency in the torsional direction and the natural frequency in the twisting direction with the torsional resonance frequency and the twisting resonance frequency of the crankshaft, the torsional resonance and the twisting resonance can be effectively suppressed.

<Verification of the Effects of the Present Invention (1)>
In the configuration (layout) of each part as shown in FIG. 2, a simulation was performed to obtain vibrations generated in the crankshaft bearing when the torsional damper shown in FIG. 1 was attached to the tip of the crankshaft of an engine and the engine was rotated.

Here, three types of torsional dampers were assumed to have a shape similar to that specifically illustrated in FIG. 1, with a natural frequency of 415 Hz when deformed in the torsional direction, and natural frequencies of 406 Hz, 490 Hz, or 674 Hz when deformed in the prying direction.
Then, the relationship between the vibration frequency of the crankshaft bearing and the acceleration of the vibration was obtained by simulation.

The results of such a simulation are shown in Figure 3. In Figure 3, the light areas (close to white) indicate that the acceleration of the vibration of the crankshaft bearing is high, and twisting vibration is occurring. Note that the top three in Figure 3 show the simulation results of twisting vibration in pitching (motion about an axis perpendicular to the rotation axis and perpendicular to the paper surface), and the bottom three show the simulation results of twisting vibration in yaw (motion about an axis perpendicular to the rotation axis and parallel to the paper surface).
It was confirmed from FIG. 3 that the torsional damper according to the present invention suppresses vibration in the twisting direction.

<Verification of the Effects of the Present Invention (2)>
As the torsional damper, a torsional damper having a shape similar to that specifically illustrated in FIG. 1 (corresponding to the torsional damper of the present invention) and, as a comparison object, a torsional damper shown in FIG. 4 (not corresponding to the torsional damper of the present invention) were assumed, and simulations were performed on these under the same conditions.
The torsional damper shown in Figure 4 has an overhang portion 9 of a similar shape and at approximately the same position as the torsional damper shown in Figure 1. However, unlike the torsional damper shown in Figure 1, the overhang portion 9 is connected to the rim portion 35 of the vibrating ring 3 and is made of the same material as the vibrating ring 3.

The measurement results of the torsional damper shown in Fig. 1 are shown in Fig. 5. Also, the measurement results of the torsional damper shown in Fig. 4 are shown in Fig. 6.
5 and 6, it was confirmed that the torsional damper according to the present invention suppresses vibration in the twisting direction (pitching) more effectively than the torsional damper of the comparative example.

1. Torsional damper (torsional damper of the present invention)
10 Torsional damper (comparative example)
REFERENCE SIGNS 3: hub 31: boss portion 33: stay portion 35: rim portion 5: vibration ring 51: pulley groove 7: rubber ring 8: overhang portion 80: inner peripheral surface of overhang portion 81: pulley groove 9: overhang portion (comparative example)
90 Inner surface of overhang portion (Comparative example)
91 Pulley groove (Comparative example)
X rotation axis

Claims (2)

a hub fixed to a tip of a rotating shaft and having an outer circumferential surface on a circumference centered on the rotating shaft;
an annular vibration ring having an inner circumferential surface on a circumference centered on the rotation axis, the inner circumferential surface having a larger diameter than the outer circumferential surface of the hub;
a rubber ring disposed between the outer circumferential surface of the hub and the inner circumferential surface of the vibration ring;
Equipped with
an overhang portion that is connected to a tip side of the vibration ring in a direction parallel to the rotation axis and further extends toward the tip ,
A torsional damper , wherein the overhang portion is cylindrical and has an inner circumferential surface on a circumference centered on the rotation axis, and the radius of the inner circumferential surface is equal to or less than the radius of the outer circumferential surface of the hub. 2. The torsional damper according to claim 1 , wherein a pulley groove is formed on an outer peripheral surface of the overhang portion.

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