JPH03186631A - Dynamic damper - Google Patents

Abstract

PURPOSE:To obtain a dynamic damper effect extending over the whole range of engine rotating speed, by filling a cavity provided in an elastic member with an electric rheology liquid, the viscosity of which changes according to the load voltage and thereby varying a spring constant of an elastic member. CONSTITUTION:A cavity 4 is provided in an elastic member 2, the cavity is filled up with an electric rheology fluid 7, the viscosity of which changes according to the load voltage, and voltage depending on the engine rotating speed is applied to an electrode 6. When the load voltage increase, the viscosity of the electric rheology fluid 7 is enlarged to increase a spring constant of the elastic member 2, so that the resonance frequency of a dynamic damper formed by a mass body 3 and the elastic member 2 is hightened. On the contrary, when the load voltage decreases, the reverse operation is caused. Thus, a dynamic damper effect can be obtained extending over the whole range of the engine rotating speed by applying the load voltage which changes in synchronization with the rotating speed of an engine to the electrodes 6, 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a dynamic damper for suppressing vibrations generated in accordance with, for example, the rotation of an engine over the entire range of rotational speed.

(Prior Art) FIG. 11 is a partial diagram showing an example of a conventional dynamic damper, and FIG. 12 is an explanatory diagram showing a vibration model of the dynamic damper.

In the figure, reference numeral 1 denotes a vibration damped body, 2 an elastic member such as rubber, and 3 a mass body having a predetermined mass that is connected to the vibration damped body 1 via the elastic member 2.

Further, in FIG. 12, K is the spring constant of the spring element of the elastic member 2, C is the damping element of the elastic member 2, and M is the mass of the mass body 3.

(Problem M to be Solved by the Invention) As shown in FIGS. 11 and 12, a conventional dynamic damper includes a mass body 3 having a mass M and an elastic member 2 having a spring constant and a damping element C. It has been stolen.

Figure 13 shows the characteristics when the frequency of the dynamic damper shown in Figure 11.12 is plotted on the abscissa and the displacement of the mass body 3 is plotted on the ordinate.Curve A shows the small damping element C. The curve B is the one when the damping element C is large.

It can be seen from this that in the conventional dynamic damper, even if the damping element C is changed, the height at the peak of the displacement of the mass changes, but the resonance frequency at the peak does not change much.

In conventional dynamic dampers, it is difficult to vary the mass M of the mass body 3 and the spring constant K of the elastic member 2, so the tuning frequency of the dynamic damper is limited to one. There has been a problem in that it is difficult to obtain a dynamic damper effect over the entire range of rotational speeds with respect to the vibrations that occur accordingly.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a dynamic damper in which a predetermined mass body is provided on a damped body via an elastic member, in which a cavity is formed in the elastic member. The cavity is filled with an electrorheological fluid whose viscosity changes depending on the load voltage, and an electrode capable of applying a voltage to the fluid is provided, and a voltage that changes depending on the excitation frequency is applied to the electrode. to configure a dynamic damper.

(Function) As described above, in the present invention, a cavity is provided in the elastic member, an electrorheological fluid whose viscosity changes depending on the applied voltage is filled in the cavity, and an electrode capable of applying a voltage to the fluid is provided. Since the viscosity of the electrorheological fluid changes depending on the excitation frequency, the ease with which the elastic member deforms is reduced. As a result of the change in the spring constant, the resonant frequency changes continuously, so a dynamic damper effect can be obtained over the entire range of excitation frequencies.

(Example) Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 10. In FIG. That is, in the figure, 1 is a damped body, 2 is an elastic member such as rubber, and 3 is a damped member.
is an X1 body having a predetermined mass and connected to the damped body l via the elastic member 2.

In this embodiment, a cavity 4 is provided in the elastic member 2, and the elastic member 2 is divided into upper and lower halves in FIGS. 1 and 2.

Further, as shown in Figs. 3 and 4, the ring made of electrical insulator is divided into two parts, each forming a semicircular arc-shaped interring 5.5, and each ink ring 5 has an electrode holding ring. A hole 5a is provided, and the interrings 5, 5 holding the electrode 6 through the hole 5a are inserted between the split surfaces of the elastic member 2, and the viscosity changes depending on the load voltage inside the cavity 4. The electrode 6 is filled with an electrorheological fluid 7, and a voltage that changes depending on the engine speed is applied to the electrode 6.

That is, 8 in FIG. 1 is a voltage generating device connected to the electrodes 6, 6, 9 is a controller connected to the voltage generating device 8, and IO is an engine rotation speed detecting device connected to the controller 9.

FIG. 5 is a characteristic diagram showing the relationship between the viscosity of the electrorheological fluid 7 and the load voltage. That is, it can be seen that as the load voltage increases, the viscosity of the electrorheological fluid 7 increases. In this case, the cavity 4 in the elastic member 2
is less likely to collapse, and the spring constant is also increased. Therefore, in this case, the resonance frequency of the dynamic damper composed of the mass body 3 and the elastic member 2 becomes high.

Furthermore, when the load voltage decreases and the viscosity of the electrorheological fluid 7 decreases, the cavity 4 within the elastic member 2 becomes more likely to collapse, and the spring constant also decreases.

Therefore, in this case, the resonant frequency becomes low.

As shown in Figure 5, the electrorheological fluid is
Since the viscosity changes continuously with respect to the load voltage,
The spring constant of the elastic member 2 also changes continuously with respect to the load voltage, as shown in FIG.

Therefore, the resonant frequency of the dynamic damper also changes continuously with respect to the load voltage, as shown in FIG.

That is, according to the present invention, in order to solve the vibration problem that occurs depending on the engine speed, a dynamic damper effect can be achieved over the entire engine speed range by applying a load voltage that changes in synchronization with the engine speed to the electrode 6.6. Obtainable.

Note that the ink ring 5 used in this example has the function of reliably holding the electrode 6 and protecting the elastic member 2.

Further, FIG. 8 is an explanatory diagram of the dynamic damper of the present invention in a state in which the electrodes 6 are not shown, and FIG. 9 is an explanatory diagram of the dynamic damper as a vibration model. In the figure, M is the mass of mass body 3, K1
is the spring constant of part ■, and K2 is I.

C1 is the spring constant of part 2, C1 is a variable damping element of part 2, and C2 is a damping element of parts I and II.

That is, the dynamic damper of the present invention has ■.

It can be expressed by a vibration system in which part ■ and part ■ are connected in series. When C,=O, the spring constant becomes a series spring with a spring constant of 1, and the spring constant becomes the smallest.As shown in Fig. 10, the resonance frequency at the peak of the displacement of the mass also changes according to the curve is the lowest as shown in .

When C+=■, the spring constant is determined by 2, and the resonance frequency at the peak of the displacement of the mass is the highest, as shown by curve H in FIG.

When CI is an intermediate value between 0 and 0, the curves E, F, and G in FIG. 10 are obtained. Therefore, the respective peaks of each of these curves DH are d and e.

If indicated by r, g, h, the curve connecting these peaks is d-e
-fgh indicates a continuous change in resonance frequency due to the dynamic damper of the present invention.

(Effects of the Invention) As described above, in the present invention, the cavity 4 is provided in the elastic member 2.
The cavity 4 is filled with an electrorheological fluid 7 whose viscosity changes depending on the load voltage, and an electrode 6 that can apply a voltage to the fluid 7 is provided, and the electrode 6 has a viscosity that changes depending on the engine speed. Since a voltage is applied, the viscosity of the electrorheological fluid 7 changes in accordance with the engine speed, which changes the ease with which the elastic member 2 deforms, and its spring constant changes. As a result, since the resonant frequency changes continuously, according to the present invention, it is possible to obtain a dynamic damper effect over the entire rotation speed range.

[Brief explanation of drawings]

Fig. 1 is a partial sectional view showing a part of the dynamic damper of the present invention, Fig. 2 is a perspective view showing its appearance, Fig. 3 is a perspective view of its interring, and Fig. 4 is the same as Fig. 3. IV-rV sectional view, Figures 5 to 7 are various characteristic diagrams, Figures 8 and 9 are explanatory diagrams of the damper of the present invention, Figure 10 is characteristic diagrams of the damper of the present invention, Figures 11 and 12 The figure is an explanatory diagram of a conventional damper.
FIG. 3 is a characteristic diagram of a conventional damper. 1... Vibration controlled body 2... Elastic member 3...
Mass body 4...Cavity 5...Ink ring 6...Electrode 7...Electrorheological fluid 8...Voltage generator 9...Controller 10
...Engine speed detection device Fig. 1 Fig. 2 Fig. 3 Fig. 5 (I/Geri 7ge) Fig. 4 Fig. 5 Fig. 6 v4 Load voltage Fig. 7 Load voltage Fig. 8 Fig. 9

Claims (1)

[Claims] 1. In a dynamic damper in which a predetermined mass body is provided on the damped body via an elastic member, a cavity is provided in the elastic member, and the cavity is filled with an electrorheological fluid whose viscosity changes depending on the load voltage. A dynamic damper characterized in that an electrode capable of applying a voltage to the fluid is provided, and a voltage that changes depending on the excitation frequency is applied to the electrode.