JPH01188737A - Vibration damper - Google Patents

Abstract

PURPOSE:To utilize sufficient vibration damping performance by detecting the pressure inside a primary chamber, applying a voltage to an electric rheological fluid inside an orifice according to the pressure variation state inside the primary chamber based on the detected data and controlling the applied voltage. CONSTITUTION:Based on the detected data of a pressure detector 14, a control means 17 is informed of the pressure variation state inside a primary chamber 4. According to the pressure variation state, a voltage is applied to the electric rheological fluid 13 inside the orifice 11 and said applied voltage is controlled. Based on the difference between the phases of both the supporting spring load of a resilient body 1 with respect to the relative displacement of a mounting member 3 and the extension spring load varying according to the pressure inside the primary chamber 4, the viscosity of the electric rheological fluid 13 flowing inside the orifice 11 is varied so that the load of the extension spring may be regulated quickly. As a result, forces generated inside a damper, including an internal force which varies inside the primary chamber 4 when the fluid moves between the primary chamber 4 and a secondary chamber 7 may be used effectively so that the sufficient vibration damping function operates.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a fluid-filled vibration damping device used in automobile engine mounting, etc., and in particular to a vibration damping device using an electrorheological fluid moving between two chambers through an orifice. This invention relates to a vibration damping device that exhibits vibration damping ability over a wide frequency range by changing viscosity.

(Prior Art) In recent years, more sophisticated vibration damping characteristics have been required for automobile engine mountings, etc., and in order to effectively damp vibrations in a wide frequency range, for example, fluid-filled vibration damping devices have been developed. It is used. In such a vibration damping device, large damping is promoted by the squeezing action of the fluid passing through the orifice due to the deformation of the elastic body when low-frequency, large-amplitude vibrations are input, such as shaking, while large damping is promoted when high-frequency, small-amplitude vibrations are input. Sometimes, vibrations are absorbed by an elastic body with a low spring constant to reduce noise such as muffled sounds. but,
The frequency characteristics of the device itself are constant, and sufficient vibration damping ability can be exhibited only within predetermined frequency ranges for large amplitude and small amplitude vibrations. To overcome this problem, it has been proposed to change the viscosity of the fluid to exhibit vibration damping ability over a wider frequency range.

As a conventional vibration damping device of this type, for example, Japanese Patent Application Laid-open No. 6
There is one described in Publication No. 0-104828. In this device, a pipe consisting of two plate electrodes is attached to an intermediate plate that defines a first chamber together with an elastic body, and when the mount is deformed by input vibration, the electrorheological fluid in the first chamber flows into this pipe. through which it flows into and out of a second chamber defined by the intermediate plate and the elastic chamber wall. In addition, a voltage is applied between the plate electrodes of the piping according to information such as the engine speed, and as the engine speed increases, the viscosity of the electrorheological fluid is lowered (and the damping force is reduced, reducing the damping force throughout the device). By changing the resonance characteristics of the sensor, it is possible to respond to input vibrations in a large amplitude range and a wide frequency range.

(Problem to be Solved by the Invention) However, in such conventional vibration damping devices, the voltage applied to the electrorheological fluid in the piping is controlled only according to external information such as engine speed. Due to this configuration, accurate voltage control, including changes in internal pressure caused by fluid passing through the piping, was not performed, and sufficient vibration damping ability could not be obtained due to the phase shift of the forces generated within the device. There was a problem.

That is, a supporting spring force corresponding to the deformation of the elastic body due to the relative displacement of both mounting members and an expansion spring force of the elastic body accompanied by a pressure change in the first chamber act within the device. The spring force varies out of phase with the supporting spring force due to the addition of a viscous damping force to the mass of electrorheological fluid passing through the pipe. Therefore, in the case of engine shake caused by excitation force from the vehicle body, when the support spring force and expansion spring force act on the engine as forces in the same phase, the force transmitted to the engine increases, and as forces in opposite phases. When it acts, the transmitted force becomes small. For this reason, with conventional vibration damping devices that do not adjust the applied voltage at any time by considering the phase of both spring forces, the transmission force with a large damping effect cannot be exerted at the optimal timing, and it is not possible to sufficiently It was not possible to obtain sufficient vibration damping ability.

(Objective of the invention) Therefore, the present invention directly detects the pressure change in the first chamber,
By controlling the applied voltage in consideration of the phase of the force generated within the device, the purpose is to effectively utilize the force generated within the device to exhibit sufficient vibration damping ability.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a first chamber which is interposed between an engine-side mounting member and a support-side mounting member, and defines a first chamber therein. an orifice provided in at least one of both mounting members, and a second chamber whose volume can be changed freely communicating with the first chamber via the orifice, and the elastic body a fluid moving means capable of moving fluid through an orifice between the first chamber and the second chamber in response to deformation of the first chamber and the second chamber;
an electrorheological fluid whose viscosity can change from liquid to almost solid depending on the applied voltage; a pressure detection means for detecting the pressure in the first chamber; A control means is provided for applying a voltage to the electrorheological fluid in the orifice according to a pressure change state in the first chamber and controlling the applied voltage.

(Function) In the present invention, the control means grasps the pressure change state in the first chamber based on the detection information of the pressure detection means, and applies voltage to the electrorheological fluid in the orifice according to the pressure change state. and the applied voltage is controlled.

Therefore, the viscosity of the electrorheological fluid flowing through the orifice is based on the phase difference between the supporting spring force of the elastic body, which corresponds to the relative displacement between the mounting members, and the expansion spring force, which varies depending on the pressure in the first chamber. is changed to quickly adjust the expansion spring force. As a result, the forces generated within the device, including internal pressure changes in the first chamber caused by the fluid moving between the first chamber and the second chamber, are effectively utilized;
Sufficient vibration damping ability is demonstrated.

(Example) Hereinafter, the present invention will be explained based on the drawings.

1 to 5 are diagrams showing one embodiment of a vibration damping device according to the present invention, and are examples in which the present invention is applied to an engine mounting device for an automobile.

In FIG. 1, 1 is a cylindrical elastic body, and the elastic body 1 is interposed between a mounting member 2 on the engine side and a mounting member 3 on the support side, and defines a first chamber 4 inside. are doing. first chamber 4
A partition plate 5 and a diaphragm 6 are attached to the upper side in the figure, and the partition plate 5 and diaphragm 6 are attached to the mounting member 2, and define a second chamber 7 whose volume can be freely changed by elastic deformation of the diaphragm 6. has been completed. Further, an outer cylinder electrode 8 and an inner cylinder electrode 9 are provided in the center of the partition plate 5, and the outer cylinder electrode 8 and the inner cylinder electrode 9 form an annular orifice 11. room 4
and the second chamber 7 are communicated with each other. These partition plates 5
, the diaphragm 6 and the orifice 11 open the first chamber 4 and the orifice 11 in accordance with the deformation of the elastic body l due to the excitation force from the engine (not shown) or the excitation force from the vehicle body which is the support body. a fluid moving means 12 capable of moving a fluid (described in detail later) between the two chambers 7;
The fluid moving means 12 is configured to damp input vibrations by the throttling action of the fluid passing through the orifice 11.

The first chamber 4 and the second chamber 7 are filled with an electrorheological fluid 13. The electrorheological fluid 13 includes a predetermined amount of particles (such as silica gel) contained in an insulating oil such as silicone oil, and the arrangement of the contained particles changes depending on the strength of the electric field based on the applied voltage. When this particle arrangement becomes extremely uniform, the state transitions to something almost solid. That is, the viscosity of the electrorheological fluid 13 changes continuously depending on the magnitude of the applied voltage, from the fluid viscosity of insulating oil to the almost solid state, and the viscosity changes continuously from the voltage application to the viscosity change. It is characterized by an extremely short reaction time (several milliseconds). Then, the viscosity of the electrorheological fluid 13 passing through the orifice 11 changes according to the voltage applied between the outer tube electrode 8 and the inner tube electrode 9 due to the operation of the fluid moving means 12, so that flow resistance such as viscous resistance increases or decreases. By changing the optimum resonance point, it is possible to exhibit vibration damping performance with different frequency characteristics, and it is possible to suppress idle vibrations with different vibration frequencies depending on the load condition or engine shake caused by excitation force from the vehicle body. It is designed to attenuate.

On the other hand, a pressure detector (pressure detection means) 14 is provided in the first chamber 4 to detect the pressure PA in the chamber, and the pressure detector 14 is connected to a control circuit 15, Changes in the pressure PA according to the relative displacement amount and the flow direction and velocity of the electrorheological fluid 13 in the orifice 11 are provided to the control circuit 15 as detection information. The control circuit 15 consists of a microcomputer, etc.
Based on the detection information of the pressure detector 14, the time differential value pa of the pressure pa and the pressure change state (details will be described later) such as the amount of pressure change from the initial pressure are identified, and the pressure change state caused by the electrorheological fluid 13 passing through the orifice 11 is identified. First chamber 4
The support spring force F and expansion spring force F2 of the elastic body 1 shown in FIG.
Output to 6. The power supply circuit 16 outputs a constant DC reference voltage v8 (for example, V=OV) to the outer cylinder electrode 8, and outputs a reference voltage v8 (for example, V=OV) to the inner cylinder electrode 9 from the same value as the reference voltage v8 in accordance with the control signal Sc. It is designed to output a DC voltage V'' that changes to a predetermined value higher than the voltage vN, and the control signal Sc prompts a change in the DC voltage V to open the orifice ll.
The voltage applied to the electrorheological fluid 13 passing therethrough is controlled. That is, the control circuit 15
And the power supply circuit 16 applies a voltage to the electrorheological fluid 13 in the orifice 11 according to the pressure change state of the first chamber 4 based on the detection information of the pressure detector 14, and a control means for controlling the applied voltage. It consists of 17.

Note that FIG. 2 is a model of the schematic configuration of this embodiment, and this embodiment has a main vibration system in which the mass M of the engine and the spring constant of the elastic body 1 are 1, and the extended spring constant of the elastic body 1. Kz, electrorheological fluid 13 in orifice 11
, and a sub-vibration system having a damping device that exerts a mass m and an orifice damping force f. In this case, if the mass m and spring constant of the secondary vibration system are set to 2 to suppress the resonance amplitude of the main vibration system, the resonance curves a, b, and C in Figure 3 are shown depending on the magnitude of the damping coefficient of the damping device. It is well known that the electrorheological fluid 13 exhibits such frequency characteristics, and when no voltage is applied to the electrorheological fluid 13 and is not controlled, the electrorheological fluid 13 exhibits the characteristics of the resonance curve C (optimal resonance curve).

Next, the effect will be explained.

Now, when relatively low-frequency vibrations (idling vibration, engine shake, etc.) are applied to one or both of the mounting members 2.3 from the engine or the vehicle body side, the elastic body 1 is elastically deformed by the excitation force, and the first The pressure p in chamber 4 of
As a changes, the transmission force (vibration damping force) between the mounting members 2 and 3 changes.

In this case, due to the phase delay characteristic of forced vibration, the electrorheological fluid 1 in the orifice 11, which is the mass m in FIG.
3 is less than the resonant frequency, the excitation displacement Xo (second
(corresponding to
It moves almost in reverse phase (180° delay). Therefore, the pressure PA in the first chamber 4 changes based on the elastic deformation of the elastic body 1, and also changes due to the movement of the electrorheological fluid 13 in the orifice 11. In each of these states, the pressure P in the first chamber 4 is determined by the pressure detector 14.
A is constantly detected, and the pressure detector 14 is detected by the control circuit 15.
The pressure change state in the first chamber 4 is identified based on the detected information of the supporting spring force Fl and the expansion spring force F! acting in the device. and its phase difference etc. can be grasped.

Specifically, the control means 17 repeats the process shown in FIG. 4 at predetermined intervals. First, the pressure detector 14
The pressure PA in the first chamber 4 which is the detection information of the control circuit 15
When the pressure P is input, the time derivative Pa is calculated, and then the pressure pa is multiplied by the time derivative I) A,
The CK value (=PaX coins) is calculated. Then, CH.E.
It is determined whether the CK value is larger than a preset negative predetermined value X, and a control signal Sc based on the determination result is output to the power supply circuit 16. Then, the DC voltage V outputted from the power supply circuit 16 to the inner cylinder electrode 9 increases to a predetermined voltage (when CHECK value>X) or decreases to the same value as the reference voltage ■8 (when CHECK value When X)
Then, the applied voltage applied to the electrorheological fluid 13 in the orifice 11 is set to 0N10FF.

That is, assuming that the expansion spring force F2 of the elastic body 1 has a waveform on the time history as shown in FIG. , the CHECK value becomes positive and the applied voltage is turned ON, and control is performed so that the damping force fc in the orifice ll increases and the expansion spring force F2 decreases, while after the mounting member 2.3 approaches the closest In section B, where they begin to separate from each other and the expansion spring force F2 decreases, the CHECK value becomes negative, the applied voltage is turned off, the damping force fC is reduced, and the expansion spring force F2 is controlled to increase. Then,
In section C, where the mounting members 2.3 are separated from each other from the initial position and the expansion spring force F2 increases in the opposite direction, the applied voltage is O.
N, and further, the applied voltage is turned off in section D where the expansion spring force F2 decreases.

During this time, the support spring force F1 fluctuates based on the amount of relative displacement of the mounting member 2.3 from the initial position.
, and the extended spring force F2 become forces in the same phase, the applied voltage is turned on, and when both spring forces become forces in the opposite phase, the applied voltage is turned off. Therefore, the vibration damping force F, which is the resultant force of the support spring force F and the expansion spring force F8, is optimally controlled in real time by changing the resonance characteristics based on the adjustment of the expansion spring force F, and sufficient vibration damping ability is exhibited. Ru. Note that the A-D section shown in Figure 5 is CHEC
The predetermined value Tight real-time damping force control is encouraged. Incidentally, the resonance curve d in FIG. 3 shows the operating state of this embodiment, and as is clear from the figure, the vibration in this embodiment is significantly greater than that of the resonance curve C (optimum resonance curve when not operating). It can be seen that the transmission rate is reduced and vibrations such as idle vibration and engine shake can be effectively damped.

In this embodiment, the second chamber 7 is provided on the mounting member 2 side, but the present invention is not limited to this, and may be provided on the mounting member 3 side or the remounting member 2.3 side. Needless to say.

(Effects) According to the present invention, the pressure in the first chamber is detected by the pressure detection means, and the electric rheostat in the orifice is controlled by the control means in accordance with the state of pressure change in the first chamber based on the detection information of the pressure detection means. Since a voltage is applied to the logical fluid and the applied voltage is controlled, the support spring force of the elastic body corresponding to the relative displacement between the mounting members and the expansion spring force that changes depending on the pressure inside the first chamber are combined. The viscosity of the electrorheological fluid flowing through the orifice can be changed based on the phase difference. As a result, the forces generated within the device, including changes in the internal pressure of the first chamber caused by the fluid moving between the first chamber and the second chamber, are effectively used, and sufficient vibration damping ability is achieved. It can be demonstrated.

[Brief explanation of the drawing]

1 to 5 are diagrams showing an embodiment of a vibration damping device according to the present invention, and FIG. 1 is a front sectional view of the vibration damping device;
FIG. 2 is a physical model diagram thereof, FIG. 3 is a graph showing its frequency characteristics, FIG. 4 is a flowchart showing its control algorithm, and FIG. 5 is a graph showing its control timing. 1...Elastic body, 2...Mounting member on the engine side, 3...Mounting member on the support body side, 4...First chamber, 7. ... Second chamber, 11 ... Orifice, 12 ... Fluid moving means, 13 ... Electrorheological fluid, 14 ...
...Pressure detector (pressure detection means), 17... Control means.

Claims (1)

[Claims] an elastic body interposed between the engine-side mounting member and the support-side mounting member and defining a first chamber therein; and an orifice provided in at least one of both mounting members; It has a second chamber whose volume can be changed freely and communicates with the first chamber, and the fluid is moved between the first chamber and the second chamber through the orifice according to the deformation of the elastic body due to the relative displacement of both mounting members. an electrorheological fluid that is sealed in a first chamber and a second chamber and whose viscosity can change from liquid to almost solid depending on an applied voltage; and detecting the pressure in the first chamber. and a control means for applying a voltage to the electrorheological fluid in the orifice and controlling the applied voltage according to the pressure change state in the first chamber based on the detection information of the pressure detection means. A vibration damping device characterized by comprising: