JPH0429149Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a torsional damper that is attached to the crankshaft of an automobile engine to damp or prevent rotational vibrations.

[Conventional technology]

Conventionally, in order to prevent vibrations of the crankshaft of an automobile engine, for example, as known from Publication of Utility Model Publication No. 145991/1987, a ring-shaped inner cylindrical metal fitting with a rotating shaft attached to the center and a ring-shaped inner cylindrical metal fitting have been used. A torsional damper that includes a rubber elastic body fixed to the outer circumference and a mass fitting fixed to the outer circumference of the rubber elastic body is attached to a rotating shaft such as a crankshaft.

As is well known, such a torsional damper is designed to be tuned to a resonance frequency with respect to the rotation of the rotating shaft, thereby suppressing the torsion angle of the rotating shaft. Therefore, conventional torsional dampers are adjusted by changing the moment of inertia of the mass fitting and the spring constant of the rubber elastic body, but only one resonance frequency is determined by this.

However, in the crankshaft of an automobile engine, as shown by curve a in FIG. 3, it is common for a plurality of resonance phenomena with different order components to appear at, for example, 4000 rpm and 6000 rpm or higher, depending on the engine speed.

Therefore, even if a conventional torsional damper with a fixed resonance frequency is attached to the crankshaft, one of the multiple resonance phenomena that appear depending on the engine speed, as shown by curve b in Figure 3. , for example, can only damp the crankshaft torsional angle around 4000rpm, and conversely, in a four-cylinder engine like this example, the second-order component of the torsional resonance of the crankshaft causes sudden crankshafts in the engine speed range of 6000rpm or higher. An increase in the shaft torsion angle appeared.

[Problem that the invention attempts to solve]

In this way, with conventional torsional dampers, the crankshaft torsional angle rapidly increases due to torsional resonance of the crankshaft.If this torsional angle is large, there is a risk of damage to the crankshaft and torsional damper. There was a problem in that the engine performance specifications were limited.

In view of such conventional circumstances, the present invention is capable of suppressing the increase in crankshaft torsional angle with respect to multiple resonance phenomena that appear depending on the engine speed with a single torsional damper. It is an object of the present invention to provide a torsional damper that can reduce the engine speed and ensure a higher maximum engine speed.

[Means for solving problems]

The torsional damper of the present invention consists of a ring-shaped inner cylindrical metal fitting with a rotating shaft attached to the center, a ring-shaped rubber elastic body fixed to the outer periphery of the inner cylindrical metal fitting, and a ring-shaped mass fixed to the outer periphery of the rubber elastic body. One or rotating metal fitting formed on the rubber elastic body on a circumference concentric with the rotation axis, penetrating the rubber elastic body in a direction perpendicular to the rotation axis and electrically insulated from the inner cylinder metal fitting and the mass metal fitting. two or more fluid chambers that are axially symmetrical;
It has an electrorheological fluid sealed in the fluid chamber, and two electrode plates supported in the electrorheological fluid so as to face each other and be electrically insulated from each other.

The fluid chamber may be formed as one continuous groove that goes around the ring-shaped rubber elastic body, or may be formed as two or more separate grooves, but in the latter case, the fluid chamber may be formed as one continuous groove that goes around the ring-shaped rubber elastic body. It is necessary to balance the rotation by arranging them symmetrically with respect to the rotation axis.

The electrorheological fluid used in the present invention is a well-known one described in, for example, US Pat. No. 3,047,507, and by applying a voltage to two electrode plates immersed therein, the It is a fluid whose viscosity increases accordingly.

[Effect]

The electrorheological fluid sealed in the torsional damper of the present invention thickens by applying a voltage between the two electrode plates, increasing its rigidity to a state close to solidification. Therefore, by controlling the voltage according to the engine speed, it is possible to change the resonance frequency of the damper and reduce the peaks of multiple torsional resonances of the crankshaft. By applying a voltage that gradually increases in the high-speed rotation region, the electrorheological fluid between the inner cylinder fitting and the mass fitting is thickened to a solidified state, thereby increasing the frictional resistance or shearing force between the two. , the crankshaft torsion angle can be suppressed.

〔Example〕

Figures 1 and 2 show a specific example of the torsional damper of the present invention, which includes a ring-shaped inner cylindrical fitting 3 made of steel integrally formed with a flange 2 at the center of which a rotating shaft 1 is attached, and an inner cylindrical member 3. Fixed to the outer periphery of metal fitting 3
It includes a ring-shaped rubber elastic body 4 made of NBR and a ring-shaped mass fitting 5 made of steel fixed to the outer periphery of the rubber elastic body 4.

In this ring-shaped rubber elastic body 4, two grooves that are to become fluid chambers 6 penetrate through the rubber elastic body 4 in a direction perpendicular to the rotation axis, and are arranged on a circumference concentric with the rotation axis 1 and symmetrical to the rotation axis 1. It is formed in A part of the rubber elastic body 4 is left in the form of a thin film for electrical insulation on the surface of the inner cylindrical fitting 3 that closes the inner circumferential side of this groove, and the outer circumferential side of the groove is covered with the peripheral wall of the mass fitting 5. Electrode supports 7b made of Teflon or the like are buried in the portions that are closed to form the fluid chambers 6, respectively, for the purpose of electrical insulation and sealing. This electrode support 7b and the electrode support 7 embedded in a part of the rubber elastic body 4 left on the inner cylindrical metal fitting 3 side
One electrode plate 8b and one electrode plate 8a are fixed to each electrode plate a, facing each other. The electrode plates 8a and 8b are made of metal such as iron, steel, or aluminum. A lead wire 11 is connected to the electrode plates 8a, 8b, extends from the electrode support 7b through the metal fitting 5, and is connected to a power source (not shown) through a slip ring 12 provided on the rotating shaft 1.

Inside the fluid chamber 6, an electrorheological fluid 10, which is a mixture of an organic solvent, pulverized silica gel, a nonionic surfactant, and water, is sealed.

Furthermore, since the rubber elastic body 4 is in contact with the electrorheological fluid,
In addition to NBR, oil-resistant rubbers such as hydrogenated NBR, ACM, CHC, and FKM are preferred, and rubbers with a thin resin film such as nylon bonded to the surface may also be used. A thin insulating film 9 made of Teflon or the like is also formed on the groove wall constituting the fluid chamber 6 of the mass fitting 5.

Further, the electrode supports 7a and 7b are preferably made of an organic solvent-resistant material having a volume resistivity of 10 ¹⁵ Ωcm or more, such as Teflon or electrically insulating rubber.

The torsional damper of the present invention explained in the above embodiment shown in FIGS. 1 and 2 is attached to the crankshaft of an automobile engine, and the torsion angle of the crankshaft according to the engine speed is measured. The results are shown in FIG. 3. It is shown in curve c. As can be seen from Fig. 3, among the sharp increases in the crankshaft torsion angle at two locations due to the original resonance of the crankshaft shown by curve a, the engine speed is
Around 4000rpm, by adjusting the moment of inertia of the mass fittings, it is reduced in the same way as a conventional torsional damper (curve b), and the engine speed
The crankshaft torsion angle due to secondary resonance above 6000 rpm can be significantly suppressed as shown in curve c by gradually applying a maximum voltage of 20 KV to the electrorheological fluid, increasing the engine speed to approximately 6500 rpm. Now I can do it.

[Effect of idea]

According to the present invention, by applying a voltage to the electrorheological fluid inside the torsional damper, the electrorheological fluid is thickened to a solidified state, and the frictional resistance or shear force between the inner cylinder fitting and the mass fitting is reduced. Since it can be increased arbitrarily, one torsional damper can attenuate all of the plurality of resonance phenomena that appear depending on the engine speed.

As a result, it is possible to reduce the sudden increase in crankshaft torsion angle in the high rotation speed range, which was a particular problem with conventional torsional dampers, to a level that does not pose a problem. It becomes possible to guarantee a higher level of guarantee, and it becomes possible to significantly improve the acceleration performance of automobiles.

[Brief explanation of the drawing]

1 and 2 show the torsional damper of the present invention, FIG. 1 is a sectional view taken along the - line in FIG. 2, and FIG. 2 is a plan view seen from the side opposite to the rotation axis. FIG. 2 is a partially cut away view of the fluid chamber at the side most opposite to the rotation axis. Figure 3 is a graph showing the relationship between engine speed and crankshaft torsion angle, where curve a represents the original torsion angle of the crankshaft without a torsional damper installed, and curve b represents the original torsion angle of the crankshaft with a conventional torsional damper installed. The curve c represents the crankshaft torsion angle when the torsional damper of the present invention is installed. DESCRIPTION OF SYMBOLS 1... Rotating shaft, 3... Inner cylinder fitting, 4... Rubber elastic body, 5... Mass fitting, 6... Fluid chamber, 7a, 7
b... Electrode support, 8a, 8b... Electrode plate, 9...
...Insulating film, 10...Electrorheological fluid.

Claims (1)

[Scope of utility model registration request] The rubber elastic body comprises a ring-shaped inner cylindrical metal fitting in which a rotating shaft is attached at the center, a ring-shaped rubber elastic body fixed to the outer periphery of the inner cylindrical metal fitting, and a ring-shaped mass fitting fixed to the outer periphery of the rubber elastic body. One or more symmetrical rings formed on the body on a circumference concentric with the rotation axis, penetrating the rubber elastic body in a direction perpendicular to the rotation axis and electrically insulated from the inner cylindrical fitting and the mass fitting. A torsional damper comprising: a fluid chamber; an electrorheological fluid sealed in the fluid chamber; and two electrode plates supported in the electrorheological fluid and opposed to each other and electrically insulated from each other.