KR20000004066A - Semi active mount using mr fluid - Google Patents

Abstract

PURPOSE: A semi active mount using the MR fluid is provided to exactly control the damping force in a wide frequency area and to detect the relative motion with a vibrating object. CONSTITUTION: The mount contains:a body(10) consisting of an upper housing(12) and a lower housing(14); an elastic member(18) inserted and installed on the upper housing(12) of the body(10) to limit or form an upper chamber(16); and a bellows(22) installed in the lower housing(14) to limit or form a lower chamber(20).

Description

Semi-active mount using MR fluid

The present invention relates to a mount for attenuating vibration transmitted to a vehicle or a mechanical structure. More particularly, the present invention relates to a vibration transmitted from an excitation source using a controllable rheological fluid such as, but not limited to, a magneto-rheological fluid. The present invention relates to a semi-active mount using MR fluid that can effectively control and attenuate the current.

In general, mounts are used to support objects or excitation sources in which vibrations may occur in a vehicle or a mechanical structure. Such mounts should be able to reduce noise and vibration by minimizing the transfer force from the excitation source to the structure. In order to dampen the transmission force, theoretically, the mount's own rigidity must be small, but in order to stably support the excitation circle, the static supporting rigidity must be properly maintained. Accordingly, the most important issue in the design of the mount is to satisfy the mutually opposite dynamic and static stiffness.

By the way, the vibration isolator made of a polymer material such as rubber employed for the execution of these requirements has sufficient support stiffness in the low frequency band where vibration rarely occurs, but sufficiently attenuates such vibration in the high frequency band where vibration occurs. Or it does not meet all of the complex characteristics that can be blocked. Accordingly, there has been a problem in recent years that can not satisfy the conditions required in the automobile industry or other general machinery industry that requires improved ride comfort or precision driving.

On the other hand, in recent years, a mount using a controllable rheological fluid, that is, a magneto-rheological fluid or an electro-rheological fluid, whose viscosity or yield stress varies depending on a magnetic field or an electric field to satisfy the above-mentioned requirements. There is a trend of active research on.

Semi-active mounts using such controllable rheological fluids, such as MR or ER fluids, perform better than conventional mounts and mechanical systems that use other fluids or solids, and do not use many mechanical elements and only use magnetic or electric fields. Since only the solenoid coil or magnetic pole plate to be applied is installed, the entire mount can be simplified, lighter and smaller, and the cost is low and the possibility of failure is significantly reduced. In addition, it can generate a wide range of continuous damping force, low power consumption of several watts, and very fast reaction. Moreover, there is an advantage in that the energy transmitted from the excitation source can be dissipated at all times, thereby maintaining stability.

As an example of various types of mounts or mechanical devices using such controllable rheological fluids, MR fluid devices are disclosed in US Patent No. 5,398,917, filed Feb. 7, 1994, entitled RO Corporation. According to the MR fluid apparatus, the solenoid coil is wound around the MR fluid-filled housing, and the MR fluid device is configured in the form of an engine mount in which a baffle plate partitioning the interior of the housing into an upper compartment and a lower compartment is embedded. The baffle plate serves to switch the flow of the fluid to be in intimate contact with the solenoid coil to affect the properties of the fluid. The engine mount also includes an elastic element joined to the attachment chamber and the first chamber as the upper chamber. In addition, an elastic blade is joined to the lower surface of the housing at the lower portion of the engine mount to form a second chamber, which is a lower chamber. The orifice in the housing is configured with a solenoid coil to form a valve for controlling the flow of the MR fluid. When a current is supplied to the solenoid coil according to such a configuration, a magnetic field is generated by the coil and applied to the MR fluid, thereby damping vibration due to the variable damping force of the MR fluid.

However, such an engine mount accurately detects the actual vibration range of the excitation source, and fails to variably supply current to the solenoid coil so that accurate damping force control cannot be achieved and can be satisfactorily processed. The disadvantage is that the frequency band of the vibration present is limited. Also similar conventional embodiments are U.S. Pat. Although variously disclosed in the foregoing, these have also been found to have problems in common with the aforementioned US Pat. No. 5,398,917.

As a result, a mount using a conventional MR fluid or an ER fluid can only control a limited damping force in a relatively small frequency range, and in particular, cannot accurately measure the damping force due to vibration attenuation and thus cannot accurately control the damping force. This was there.

Accordingly, the present invention has been made to solve the above-described problems, the object of the present invention is to control the accurate damping force in a wide range of frequencies, and also using an MR fluid that can detect the relative motion with the vibration object To provide an active mount.

It is still another object of the present invention to provide a semi-active mount using an MR fluid capable of detecting a relative motion with an excitation source which is a vibration generating object and changing an amplification ratio arbitrarily or in accordance with a vibration state.

The objects as described above are achieved by the present invention, in accordance with an aspect of the present invention, to form an upper housing forming an upper chamber filled with MR fluid and a lower chamber in communication with the upper chamber and filled with MR fluid. A main body having a lower housing, a circular plate partitioning the upper chamber and the lower chamber so as to communicate with the MR fluid, an annular coil for applying a magnetic field to the MR fluid in the main body, displacements of the upper and lower ends of the main body, A magnetic generating device capable of adjusting the intensity of the magnetic field applied to the annular coil according to the speed signal, and between the upper and upper circles of the main body and / or between the lower part of the main body and the support on which the main body is mounted and generating the magnetic Characterized by consisting of an active element connected to the device and deformed by a magnetic field applied therefrom to damp vibrations Semi-active mounts using MR fluid are provided.

According to another aspect of the present invention, a body having an upper housing forming an upper chamber filled with MR fluid and a lower housing communicating with the upper chamber and forming a lower chamber filled with MR fluid, and the upper chamber and the lower chamber. A circular plate partitioning the chamber so that the MR fluid can communicate therewith, an annular coil for applying a magnetic field to the MR fluid in the main body, a magnet protruding from the upper end of the main body to directly apply induced electromotive force to the annular coil; MR is installed in the lower portion of the excitation source fixed to the upper end of the main body having an induction coil surrounding the magnet and made of an induction electromotive force generating device for generating induction electromotive force by the relative movement between the magnet and the induction coil Semi-active mounts with fluids are provided.

1 is a block diagram showing a first embodiment of a semi-active mount using an MR fluid according to the present invention.

Figure 2 is a block diagram showing a second embodiment of a semi-active mount using the MR fluid according to the present invention.

Figure 3 is a schematic diagram showing the electromotive force generation principle of the induction electromotive generator of Figure 2;

Figure 4 is a block diagram showing a third embodiment of the mount according to the present invention.

♣ Explanation of symbols for the main parts of the drawing ♣

10: main body 12: upper housing

14: lower housing 16: upper chamber

18: elastic member 20: lower chamber

22: bellows 24: round plate

26: spacer 28: magnetic field applying region

30: annular coil 32: fixing piece

34: support member 36: active element

38: magnetic generator 44: induction electromotive force generator

46: induction coil 50: amplification device

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing a first embodiment of a semi-active mount using an MR fluid according to the present invention.

As shown in FIG. 1, the mount according to the invention basically comprises a body 10 consisting of an upper housing 12 and a lower housing 14. The upper housing 12 of the main body 10 is inserted with an elastic member 18 defining or forming the upper chamber 16 in which the MR fluid is filled, and the lower housing 20 in the lower housing 14. The bellows 22 defining or forming it is implied. Of course, the elastic member 18 of the upper housing 12 has an expansion stiffness to support not only the vertical static load and the horizontal load of the excitation circle but also the dynamic load of the excitation circle, and also of the lower housing 14 The bellows 22 preferably has some expansion stiffness to variably store the MR fluid flowing from the upper chamber 20.

On the other hand, actually partitioning the inside of the main body 10 into the upper chamber 16 and the lower chamber 20 is a circular plate 24 provided between the upper housing 12 and the lower housing 14, the circular plate ( 24 are spaced apart from each other by spacers 26 provided between them and respective housings 12 and 14.

In addition, the joints of the respective housings 12 and 14 are provided with a magnetic field applying region 28 in which a magnetic field is applied to the MR fluid in the respective housings. Thus, in order to apply an actual magnetic field to the MR fluid, An annular coil 30 is installed in a solaid manner in a space between the housings 12 and 14 and around the circular plate 24.

Reference numeral 32 is a fixing piece to be inserted into the fixing hole of the excitation circle, 34 is actually a supporting member for reinforcing the elastic rubber.

In particular, the active element 36 is mounted on the stationary piece 32 which is fixed to the mount according to the invention, more particularly to the excitation source, such as the engine of an automobile. The active element 36 may be inserted between the upper and upper circles of the main body 10 or between the lower portion of the main body 10 and the support on which the main body 10 is mounted, or both. In particular, the active element 36 is preferably formed of a magneto-strictive material because the magnetostrictive material has a wide frequency band, a large displacement amount, and a strong opposing force against compression force. .

In addition, the mount according to the present invention is associated with a magnetic generating device 38 capable of applying a magnetic field to the MR fluid and / or active element 36 as well as adjusting the strength of the magnetic field. The magnetic generating device 38 preferably includes a control unit including a central processing unit (CPU) for controlling the strength of the magnetic field and an amplifier (AMP) capable of amplifying the magnetic field to a predetermined size.

On the other hand, as shown in the dashed line in the figure, the magnetic generating device 38 is connected to the detection sensors that can measure whether the vibration in the excitation circle or mount and the magnitude of the vibration and transmit the signal, the detection One of the sensors, the sensor 40 is installed between the upper housing 12 and the excitation circle (not shown) to detect the relative speed and displacement between the excitation circle and the top of the mount and transmit it to the magnetic generating device 38. The other sensor 42 is installed between the lower housing 14 and a frame (not shown) to which the mount is fixed, and detects relative speeds and displacements between them and transmits the signal to the magnetic generating device. Of course, the actual installation position of each sensor 40, 42 can be appropriately set as needed as long as it can accurately detect the displacement and speed of the top and bottom of the mount as described above.

The operation of the mount according to the first embodiment of the present invention made as described above is as follows.

Basically, as the current is applied to the annular coil 30, a magnetic field is induced around the annular coil 30, and the magnetic field induced by the current is the MR between the upper housing 12 and the lower housing 14. Fluid, that is, MR fluid in the magnetic field applying region 28 indicated by the dotted line. At this time, the magnetic field from the annular coil 30 passes through the MR fluid in the upper portion of the circular plate 24, the circular plate 24, and the MR fluid in the lower portion of the circular plate 23. It will form a line of magnetic force. Accordingly, the waste magnetic force line flows through the MR fluid flowing up and down along the circumference of the circular plate 23, and the viscosity of the MR fluid changes as the magnetic field is applied to the MR fluid, thereby changing the vibration damping force.

At this time, the displacement and the relative speed of the top and bottom of the mount is sensed by the sensing sensors 40 and 42 disposed at the top and bottom of the mount, respectively, and the respective signals are transmitted to the magnetic generating device 38. Then, the magnetic generating device 38 processes the signal to generate a predetermined current or amplifies the current to supply the annular coil 30 so that the current value applied to the annular coil 30 is varied. In this way, if the intensity of the magnetic field induced in the annular coil 30 is varied, the viscosity of the MR fluid is also varied according to the strength of the magnetic field, so that vibration from the excitation source can be appropriately attenuated.

In particular, at the same time a magnetic field from the magnetic generating device 38 is applied to the active element 36 inserted between the excitation circle with the main body 10 and / or between the main body 10 and the support. When a magnetic field is applied to the active element 36 as described above, vibration can be attenuated while expanding or contracting due to its own characteristic, that is, magnetic deformation.

Accordingly, the vibration generated from the excitation source can be controlled both by the variable action of the viscosity of the MR fluid according to the variation of the magnetic field applied by the annular coil 30 and by the magnetostriction of the active element 36. It can be attenuated effectively. In particular, since the control force of the high frequency band is provided by the active element 36 in the above-described dustproof control, it is possible to attenuate the vibration of a wider frequency band. Of course, when the active element 36 is provided on the upper and lower parts of the main body 10, the vibration can be more efficiently and complexly attenuated.

Figure 2 shows a second embodiment of a semi-active mount using an MR fluid according to the present invention.

As shown in FIG. 2, the mount according to the second embodiment of the present invention includes the basic components as in the first embodiment described above. The same reference numerals used for the mount will be used.

The mount according to the second embodiment is provided with an induction electromotive force generator 44. In more detail, the induction electromotive force generating device 44 includes a magnet 46 protruding from the upper end of the main body 10 of the mount, and an induction coil 48 installed in an excitation circle, which is an object mounted on the mount. Include. In this case, the magnet 46 is formed in a rod shape, and the induction coil 48 is wound in a winding shape to surround the magnet 46. Therefore, as the principle is disclosed in FIG. 3, the induction electromotive force generator 44 causes the magnet 46 to reciprocate in the induction coil 48 when the vibration is generated in the excitation source, or conversely, the induction coil 48 becomes the magnet. Reciprocating relative to (46) to generate an electromotive force proportional to their relative motion. On the other hand, the induction electromotive force generator 44 is connected to the annular coil 30 by a connecting means such as a wire (not shown) to directly apply the electromotive force generated in the induction electromotive force generator 44 to the annular coil 30 can do.

As a result, the mount according to the second embodiment of the present application directly uses the inductive electromotive force generating device 44 in which electromotive force is generated at the same time when vibration is generated without requiring a separate magnetic field generating device as in the first embodiment. It is configured to apply to).

Looking at the operation of the mount according to the second embodiment of the present invention made as described above are as follows.

When vibration occurs in the excitation source fixed to the mount, the magnet 48 fixed to the mount reciprocates with respect to the induction coil 46 fixed to the excitation circle, or the induction coil 46 with respect to the magnet 48. This reciprocation causes relative movement between each other. As such, when relative motion is made between the induction coil 46 and the magnet 48, an induced electromotive force e is generated, and an induction current i flows through the induction coil 46.

The induced electromotive force (e) generated in this way is directly supplied to the annular coil 30, and the viscosity of the MR fluid is changed as the induced electromotive force supplied to the annular coil is applied to the MR fluid to control the damping force. . Of course, the intensity of the induced electromotive force is proportional to the relative motion between the induction coil 46 and the magnet 48, so that the magnitude of the electromotive force applied to the annular coil 30 varies in proportion to the magnitude of the vibration generated every time in the excitation circle. At the same time, the electromotive force applied to the MR fluid is also variable so that the variable force of the MR fluid can be controlled to effectively damp the vibration.

The generation of electromotive force in the induction electromotive force generator 44 is caused by the change of the magnetic flux passing through the induction coil 46, the magnitude of the induced electromotive force is directly proportional to the rate of change of the magnetic flux per unit time, It is directly proportional to the number of turns. Accordingly, the number of turns can be appropriately set as needed to properly drive the MR fluid in the mount, so that a predetermined induced electromotive force can be provided.

However, the mount according to the second embodiment may be very effective when the vibration generated in the excitation source is relatively weak or the damping force required in the mount is small, but the vibration generated in the excitation source is relatively large or the If the mount requires a large damping force, this may not be appropriate. Of course, it is also possible to increase the number of windings of the induction coil to increase the damping force of the mount, but the range is not desirable because of the limited design of the mount.

Accordingly, when the induced electromotive force generated therefrom in the mount provided with the induction electromotive force generating device is limited, a means for increasing the intensity of the electromotive force applied to the annular coil is required. Such an embodiment is a third embodiment of the present invention. 4 is shown.

According to FIG. 4, an amplifying device 50 is connected to the induced electromotive force generating device 44, which is also connected to the annular coil 30. Accordingly, the induced electromotive force generated in the induced electromotive force generating device 44 by the vibration of the excitation circle is transmitted to the amplifying device 50, and the amplifying device 50 amplifies the induced electromotive force to a predetermined size and annular coil it. Is applied to (30). On the other hand, the amplifier 50 may simply include only a power amplifier that serves to amplify the induced electromotive force generated from the induction electromotive force generator 44.

However, the amplifier 50 may include the control unit described in the first embodiment in addition to the power amplifier to process the induced electromotive force received from the induction electromotive force generator 44 so that the power amplifier generates a predetermined induced electromotive force. The electromotive force can be applied to the annular coil. In this case, the induced electromotive force generating device merely serves as a sensor for detecting the magnitude of vibration of the excitation source. In this case, the practical use of the mount can be greatly improved by replacing the induction electromotive force generator coupled to the mount, which eventually serves as a sensor necessary for controlling the damping force of the mount.

Accordingly, when vibration is generated in the excitation source, electromotive force is generated by the relative movement of the induction coil generator and the magnet, and the induced electromotive force is supplied to the amplifying device 50. The electromotive force supplied to the amplifying apparatus 50 is amplified to a predetermined size by a power amplifier, and the amplified electromotive force is applied to the annular coil 30.

Since the viscosity of the MR fluid is changed by the electromotive force applied to the annular coil it is possible to damp the vibration. Of course, the amplification device 50 amplifies the induced electromotive force in proportion to the magnitude of the vibration generated every time in the excitation source, so that the magnitude of the electromotive force applied to the annular coil 30 is varied and is applied to the MR fluid. The electromotive force is also variable so that the variable force of the MR fluid can be controlled to damp vibration. Of course, when the control unit is included in the amplification device 50, the power amplifier can generate a predetermined electromotive force by processing and interpreting the electromotive force signal received from the induction electromotive force generator, thereby effectively controlling the damping force.

On the other hand, in order to implement a preferred embodiment of the present application as described above MR fluid is selected as the controllable fluid included in the mount, but other controllable fluid ER fluid may be used in the same manner, as described above When the fluid is filled in the mount, it is understood that the annular spring for applying the magnetic field to the MR fluid only needs to be replaced by the electrode plate for applying the electric field to the ER fluid.

As described in detail above, according to the semi-active mount using the MR fluid according to the present invention, in the low frequency region or the resonance point, the vibration can be attenuated using the damping force of the MR fluid, and the stiffness and the attenuation of the active element are reduced in the high frequency region. Vibration can be attenuated to control both low frequency and high frequency vibrations.

In addition, by using electromagnetic induction phenomenon, the electromotive force is generated by the relative movement between the mount and the excitation source, and the damping force of the MR fluid can be controlled by using the electromotive force as the magnetic field generating source, so that a separate magnetic field generating means can be omitted. This can be improved.

In addition, it is possible to control the damping force of the mount by detecting and amplifying the relative motion between the mount and the excitation circle by using electromagnetic induction phenomenon. Can be controlled.

Claims (6)

A main body 10 having an upper housing 12 forming an upper chamber 16 filled with MR fluid and a lower housing 14 communicating with the upper chamber and forming a lower chamber 20 filled with MR fluid. A circular plate 24 partitioning the upper chamber 16 and the lower chamber 20 in such a manner as to allow the MR fluid to communicate therewith; an annular coil 30 for applying a magnetic field to the MR fluid in the main body 10; A magnetic generating device 38 capable of adjusting the intensity of the magnetic field applied to the annular coil according to the displacement and velocity signals of the upper and lower ends of the main body 10, between the upper part of the main body 10 and the excitation circle; Or an active element 36 inserted between a lower portion of the main body 10 and a support on which the main body 10 is mounted, connected to the magnetic generating device 38, and deformed by a magnetic field applied therefrom to attenuate vibration. Semi-active horse using MR fluid, characterized in that consisting of Unt. The semi-active mount according to claim 1, wherein the active element (36) is formed of a magnetostrictive material. A main body 10 having an upper housing 12 forming an upper chamber 16 filled with MR fluid and a lower housing 14 communicating with the upper chamber and forming a lower chamber 20 filled with MR fluid. A circular plate 24 partitioning the upper chamber 16 and the lower chamber 20 in such a manner as to allow the MR fluid to communicate therewith; an annular coil 30 for applying a magnetic field to the MR fluid in the main body 10; Induction to surround the magnet 46 is installed in the lower portion of the magnet 46 protruding from the upper end of the main body 10 and the excitation circle fixed to the upper end of the main body 10 to directly apply the induced electromotive force to the annular coil Semi-active mount having an MR fluid comprising a coil 48 and made of an induced electromotive force generator 44 for generating induced electromotive force by relative movement between a magnet and an induction coil. The semi-active mount according to claim 3, wherein the induction electromotive force generator (44) is a relative speed detection sensor capable of detecting the relative speed between the excitation source and the mount. The method of claim 4, further comprising amplifying device 50 for amplifying the induced electromotive force generated from the induced electromotive force generating device 44 to the annular coil 30, characterized in that the semi-active using MR fluid Mount. The method according to any one of claims 3 to 5, wherein the amplifying device 50 is configured to change the amplification ratio according to the vibration state of the source having the current or voltage generated from the induction electromotive force generating device 44. Semi-active mount using MR fluid.