JPH026934B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mounting device for a power unit, and in particular, a mounting device between a vehicle body and a power unit that can arbitrarily change spring characteristics and damping characteristics depending on the driving condition of the vehicle. The present invention relates to an interposed mounting device.

Conventionally, when installing a power unit in which an engine and a transmission are integrated into a vehicle body, it is necessary to support the power unit and suppress the transmission of vibration input from the engine and vibration input from the road surface during driving. Also, a structure is adopted in which a mounting device for damping or preventing vibration is interposed between the power unit and the vehicle body.

Therefore, such mounting devices generally have vibration damping characteristics for suppressing vibrations of 5 to 30 Hz due to input from the road surface during driving and input from the power unit during idling, and vibration damping characteristics for suppressing vibrations of 5 to 30 Hz due to input from the road surface during driving and input from the power unit during idling. Anti-vibration properties are required to prevent vibrations from inputs of 30 Hz or higher coming from the unit, but the conventional mounting structure in which insulator rubber is interposed between two mounting brackets does not provide this control. When a rubber material with good damping performance is used to produce a vibration effect, the spring constant becomes high in the high frequency range, and therefore the vibration transmission force increases, making it impossible to obtain a good vibration isolation effect. On the other hand, if a rubber material with a small spring constant is used in order to improve the vibration damping effect, the loss coefficient will be small and therefore the damping performance will deteriorate.

In particular, high damping and high spring characteristics are used to suppress vibration or movement of the power unit during engine shake or sudden torque fluctuations such as during sudden starts or sudden accelerations. On the other hand, when idling or driving at high speeds, it is desirable to have a mount function with low spring characteristics to reduce the transmission rate of vibration input from the power unit to the vehicle body. However, conventional mounting devices have not necessarily been able to meet this demand.

On the other hand, elastic supports with a structure that utilizes the elasticity of rubber and fluid flow resistance, so-called fluid-filled mounts, have been proposed. One chamber (liquid chamber) and the other chamber (liquid chamber) are separated by a fixed partition plate, and an orifice of an appropriate diameter and length is provided in the partition plate, and the liquid is allowed to flow through the orifice. A structure has been revealed in which a large loss coefficient can be exhibited in the low frequency range by flowing the gas from one chamber to the other.

However, in the case of such a structure,
In response to vibrations in the high frequency range, it becomes difficult for the liquid to flow through the orifice, and the liquid pressure inside the liquid chamber increases, which inevitably increases the dynamic spring constant.
This is not desirable as a mounting device for a power unit such as the one described above. Barefoot,
This is because if the amount of volume change during vibration is increased in an attempt to increase the loss coefficient in the low frequency range, the dynamic spring constant in the high frequency range will also increase at the same time.

The present invention has been made against this background, and its purpose is to improve the damping performance and spring constant, which are the basic performance, in the fluid-filled mounting device as described above. , so that it can be changed as appropriate depending on the driving condition of the vehicle, thereby making it possible to easily and effectively exhibit both the vibration damping characteristics in the low frequency range and the vibration damping characteristics in the high frequency range. The goal is to provide a structure that allows for

In order to achieve this object, the present invention provides an elastic body on one side of the partition member to form a pressure receiving chamber within the elastic body, and at least An equilibrium chamber is formed by an enclosure, a part of which is made of a flexible thin film, and the pressure receiving chamber and the equilibrium chamber are communicated with each other, while a predetermined incompressible fluid is sealed in the pressure receiving chamber and the equilibrium chamber.
In a mounting device interposed between a vehicle body and a power unit, (a) a state in which the passage cross-sectional area is large and a state in which the passage cross-sectional area is small are selected for communicating the pressure receiving chamber and the equilibrium chamber; (b) a third liquid chamber provided within the elastic body and communicated with the equilibrium chamber; and (c) the pressure receiving chamber due to the large passage cross-sectional area of the orifice mechanism. a first operating position that allows communication between the third liquid chamber and the equilibrium chamber and allows fluid flow between the third liquid chamber and the equilibrium chamber; and a state in which the passage cross-sectional area of the orifice mechanism is small. an actuating member that takes two positions; a second actuating position that communicates between the pressure receiving chamber and the equilibrium chamber by a chisel, and a second actuating position that prevents fluid flow between the third liquid chamber and the equilibrium chamber; (d) supporting means for holding the actuating member in one of the two actuating positions; and (e) energized by an external electrical input, the excitation causing the actuating member to electromagnetic means for activating and positioning the electromagnet in the other of the two operating positions against the holding action of the supporting means;
It was established.

Therefore, according to the configuration of the present invention, the large cross-sectional area of the passage in the orifice mechanism that communicates the pressure-receiving chamber and the equilibrium chamber is controlled by the electromagnetic means actuated by external electrical input. By selectively operating the magnetization of the actuating member, the flow resistance based on the flow of incompressible fluid between the pressure receiving chamber and the equilibrium chamber in a state where the cross-sectional area of the other passage is small can be arbitrarily expressed. It became a matter of getting it. That is, by controlling the electromagnetic means according to the driving conditions of the vehicle, it is possible to achieve a mount function that can most effectively attenuate or isolate vibrations input in various driving conditions. It has become possible to exhibit both vibration damping properties in the low frequency range and vibration isolation properties in the high frequency range.

In addition, according to the mounting structure of the present invention, the incompressible fluid is trapped in the third liquid chamber provided in the elastic body by preventing the fluid from flowing into the equilibrium chamber, and this This contributes to an increase in the dynamic spring constant of the mounting as a whole, thereby providing a high dynamic spring constant with a low dynamic spring characteristic at the same frequency, for example at a frequency of 15 Hz.
It has become possible to realize a mounting function that can exhibit high attenuation characteristics.

Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail based on the drawings.

First, FIGS. 1 and 2 show an embodiment of the mounting device of the present invention. Reference numeral 2 denotes a mounting fitting, which has a mounting bolt 6 fixed to the engine side member, which is fixed so that the threaded portion thereof penetrates the center of the flat plate 4 and projects outward. There is. The mounting fitting 2 is fluid-tightly attached to an upper plate 10 provided at the end of a cylindrical rubber block 8 as an elastic body by caulking.

Further, the lower part of the rubber block 8 is fixed to one side of a partition plate 12 which is a partition member. Therefore, inside the rubber block 8, there is a pressure receiving chamber 14 defined by the plate 4 of the upper mounting bracket 2 and the lower partition plate 12.
It is formed approximately in the center. Also,
Inside the rubber block 8, as shown in FIGS. 1 and 2, there are two arc-shaped sub-liquid chambers (third liquid chamber) 16, 16 located outside the pressure-receiving chamber 14.
is provided. An outer restraint ring 18 and an inner restraint ring 20 are buried so as to be located on the outer circumferential surface of the rubber block 8 and the inner surface of the sub-liquid chamber 16, respectively, to prevent the rubber block 8 from deforming outward in the radial direction. bulge). Note that the upper plate 10, the partition plate 12, and the outer and inner restraint rings 18, 20 can be easily manufactured as an integral member by being vulcanized and bonded at the same time when the rubber block 8 is vulcanized and molded. be.

A stepped portion of the opening of a bottomed cylindrical protective cap 22 is caulked to the peripheral edge of the partition plate 12, and this caulking action causes a diaphragm 24 as a flexible thin film to open. The peripheral edge is pressed against the partition plate 12,
Therefore, between the partition plate 12 and the diaphragm 24,
A liquid-tight partitioned equilibrium chamber 26 of variable volume is formed. A mounting bolt 28 is disposed approximately in the center of the protective cap 22, and the threaded portion of the protective cap 22 is inserted through the mounting bolt 28 so as to protrude outward. It is adapted to be attached to a mounting member (not shown). In addition, the through hole 30 of the protective cap 22
is a through hole for allowing air to circulate inside and outside the protective cap 22.

Furthermore, a recess is formed on the side of the partition plate 12 facing the equilibrium chamber 26, into which a core member 32 made of magnetic material is attached and fixed via a layer 34 of non-magnetic material. There is. Further, a coil 36 is arranged around the core member 32, and the core member 32 is excited by input to the coil 36 from an external power source. That is, such a coil 3
The electrical input to 6 is performed under the control of a control device 38, as shown in FIG. It receives signals from the opening sensor, shift lever position sensor, etc., uses the logic circuit to identify the running state of the vehicle, and based on this, a predetermined current (voltage) is turned on and off to the coil 36. It is becoming.

In addition, a core member 32 disposed on the partition plate 12
A cylindrical rubber sleeve 42 having an inwardly projecting wall surrounds the electromagnetic means consisting of a coil 36 and a coil 36, and a seat 44 fixed at its base is fitted into the fixing member. A valve plate (operating member) 46 made of a magnetic material such as iron is fixed to the opening of the rubber sleeve 42. Note that the seat 44 and the valve plate 46 can be vulcanized and bonded simultaneously when the rubber sleeve 42 is vulcanized and molded. Then, this rubber sleeve 42, the valve plate 46, and the partition plate 1
An intermediate chamber 48 surrounded by 2 is formed within the equilibrium chamber 26.

In the cross-sectional area of the passage that penetrates the partition plate 12 so as to open into the intermediate chamber 48,
A first orifice 50 having a small cross-sectional area and a second orifice 52 having a large cross-sectional area are further provided through the core member 32, and are formed in the intermediate chamber 48 and the rubber block 8. A passage 5 that connects the two sub-liquid chambers 16 to each other.
4 is provided to penetrate the partition plate 12.
On the other hand, a valve plate 46, which is fixed to a rubber sleeve 42 serving as a support member and held at a predetermined distance from the end face of the core member 32 where the first and second orifices 50, 52 are opened, has a At a position corresponding to the opening of the first orifice 50,
A large through hole 56 is formed so that when the valve plate 46 is magnetically attached by energizing the electromagnetic means comprising the core member 32 and the core member 36, the surface of the valve plate 46 allows a second The opening of the first orifice 52 is closed, while the opening of the first orifice 50 is not closed, so that the equilibrium chamber 26 and the pressure receiving chamber 14 are connected to each other through the through hole 56. Communication is established through one orifice 50.

Note that due to the magnetic attachment of the valve plate 46 to the core member 32, the intermediate chamber 48 is isolated from the equilibrium chamber 26 and the pressure receiving chamber 14, and communicates only with the sub-liquid chamber 16 formed within the rubber block 8. It becomes a sealed room.

In addition, the pressure receiving chamber 14, the sub-liquid chamber 16 as a third liquid chamber, the equilibrium chamber 26, and the intermediate chamber 48 contain water, polyalkylene glycol (for example, polyethylene glycol, etc.), silicone oil, and low molecular weight polymers, respectively. Predetermined incompressible fluids, such as 54 and further through the through holes 56, allowing free flow between the chambers.

Therefore, in the mounting device configured as described above, when the coil 36 is energized under the control of the control device 38 in accordance with the driving state of the vehicle, the core member 32 and the coil 36 are connected to each other by an electromagnet. Due to the excitation, the valve plate 46 held by the rubber sleeve 42 is attracted against the holding action of the rubber sleeve 42 and is magnetically attached. In this magnetic state, the second orifice 52 is connected to the valve plate 46.
However, the first orifice 50 is maintained in an open state due to the presence of the through hole 56. Therefore, the communication between the pressure receiving chamber 14 and the equilibrium chamber 26 is 50 and therefore the flow of incompressible fluid between those two chambers takes place only through the first orifice 50 and therefore
By appropriately setting the diameter (cross-sectional area) and length of 0, the incompressible fluid in the pressure receiving chamber 14 reaches the equilibrium chamber 26 through the first orifice 50 in response to the vibration input. The flow resistance caused during this process causes large viscous damping, and the springs of the rubber part 8 that restrain the incompressible fluid act in parallel, increasing the dynamic spring constant, although this is not sufficient. It will be done.

In the structure of the above example, a sub-liquid chamber 16 is further provided within the rubber portion 8.
When the valve plate 46 is magnetized as described above, the sub-liquid chamber 16 is connected to the rubber sleeve 42.
The interior of the sub-liquid chamber 16 is in communication only with the closed space surrounded by the valve plate 46 and the partition plate 12, and is cut off from the other liquid chambers 14 and 26. The incompressible fluid is
Since the fluid in the intermediate chamber 48 is confined together with the fluid, and since this fluid is incompressible, the constraint condition of the rubber portion 8 forming the secondary liquid chamber 16 and the rubber sleeve holding the valve plate 46. 42 (spring) acts as a spring, and the rubber part 8 is connected in parallel with the spring acting as a support.
Therefore, a high dynamic spring constant can be realized.

On the other hand, when the power to the coil 36 is cut off by the control device 38, the valve plate 46, which was magnetically attached to the core member 32, returns to its original state (returns to its original state) due to the restoring force (elasticity) of the rubber sleeve 42. 1), thereby causing the valve plate 46 of the second orifice 52 to
From the point where the blockage due to
The equilibrium chamber 26 and the first orifice 50 are in an open state in which they are also communicated by the second orifice 52, and the auxiliary liquid chamber 16 is also communicated with the valve plate 46 through the intermediate chamber 48. It is in an open state where it is communicated with the pressure receiving chamber 14 and the equilibrium chamber 26 through the hole 56 and the first and second orifices 50 and 52.

In such a released state, the incompressible fluid in the pressure receiving chamber 14 and the sub-liquid chamber 16 smoothly follows the change in the rubber block 8 when vibration is input from the outside, and is hardly involved as a spring. Therefore, the constraint of the diaphragm 24 that forms the equilibrium chamber 26 only plays a role as a spring. In other words, due to the increased cross-sectional area of the orifice, the fluid can move smoothly between each chamber, and there is almost no attenuation at the orifice. Since almost no spring is generated, the original spring of the rubber of the rubber block 8 becomes the main component, and soft spring characteristics are realized, thereby achieving low dynamic spring and low damping characteristics.

As described above, the damping performance of the mounting device having such a structure is determined by the core member 32 and the coil 36.
In other words, communication between the pressure receiving chamber 14 and the equilibrium chamber 26 is established by controlling the cross-sectional area of the orifice through the operation of an electromagnetic means constituted by the first orifice 5.
0 only, or first and second orifices 50,
By doing this at step 52, control becomes possible. By appropriately reducing the cross-sectional area of the orifice, damping can be increased, and the spring constant of the pressure receiving chamber 14 can be adjusted by decreasing the cross-sectional area of the orifice.
By restricting the flow of liquid between the auxiliary liquid chamber 16 and the equilibrium chamber 26, and by keeping the liquid in the sub-liquid chamber 16 confined within the liquid chamber, it is effectively increased. High dynamic spring characteristics can be exhibited.

As described above, the dynamic spring and damping characteristics of the mounting device can be controlled by the operating state of the electromagnetic means consisting of the core member 32 and the coil 36, which is controlled by the external control device 38. The spring constant and damping force of the mounting device can be changed arbitrarily depending on the driving conditions of the vehicle, such as when the vehicle is idling or driving at high speeds, when there is a sudden change in torque, when the vehicle is idling, or when driving at high speed. This enabled us to take the most suitable vibration countermeasures.

FIG. 3 shows another embodiment of the mounting device according to the present invention, which is structurally similar to the embodiment described above, so similar parts have the same structure. The reference numerals are given and explanations are omitted, and only the different parts will be described below.

First, in the mounting device shown in Fig. 3,
The rubber block 8 has a structure in which it is vulcanized and bonded directly to the plate 4 of the mounting fitting 2, while a lower plate 58 is vulcanized and bonded to the end of the rubber block 8 on the partition member side. Therefore, unlike the previous example, the rubber block 8 is not directly vulcanized and bonded to the partition member. This is based on the consensus on the method of forming the pressure receiving chamber 14 and the sub-liquid chamber 16 formed within the rubber block 8. In the previous example, the pressure receiving chamber 14 and the sub-liquid chamber were formed from the engine mounting bracket 2 side of the rubber block 8. 16 in a vulcanization mold into which a pin or member to be formed is inserted, the rubber block 8 is
has a structure that is vulcanized and molded,
In this embodiment, the rubber block 8 is vulcanized in a vulcanization mold while the pins or members for forming the pressure receiving chamber 14 and the sub-liquid chamber 16 are inserted from the partition member installation side. This is becoming more and more common. For this reason, the lower plate 58 fixed to the rubber block 8 is formed with corresponding openings 60 and 62 of a size corresponding to the pressure receiving chamber 14 and the sub-liquid chamber 16.

Further, the partition member is composed of a plate 64 that is brought into contact with the opening 60 of the lower plate 58 from below so as to close it, and a core member 66, and a peripheral edge of the core member 66. but,
The protective cap 22 is held liquid-tight by caulking the lower plate 58, and the attachment of the plate 64 and the core member 66 forms the pressure receiving chamber 14 within the rubber block 8, while the pressure-receiving chamber 14 is connected to the diaphragm 24. An equilibrium chamber 26 is formed between them. Further, a first orifice 50 with a small cross-sectional area and a second orifice 52 with a large cross-sectional area are respectively provided through the plate 64 and the core member 66, and further communicate the sub-liquid chamber 16 with the equilibrium chamber 26. In order to achieve this, the core member 66 is provided with a passage 54 having a large cross-sectional area that does not adversely affect the flow of fluid within the sub-liquid chamber 16.
is formed. Further, the coil 36 is inserted and disposed within the core member 66 so as to be located outside the first and second orifices 50 and 52.

The valve plate 46, which is magnetically attracted to the electromagnetic means constituted by the core member 66 and the coil 36, is held liquid-tight at its peripheral edge by an annular rubber 68. The outer peripheral edge of the diaphragm 24 is held in pressure contact with the core member 66 together with the peripheral edge of the diaphragm 24 by the caulking action of the protective cap 22 . As a result, the core member 66 and the valve plate 4
6, the valve plate 46 is held by the annular rubber 68, and the intermediate chamber 48 is formed between the valve plate 46, the annular rubber 68, and the core member 66. The pressure receiving chamber 14 and the sub-liquid chamber 16 are connected to the first and second orifices 50 and 5 via the intermediate chamber 48.
2. At the passage 54 and through hole 56, the equilibrium chamber 26
The structure is such that it communicates with the

Therefore, even in a mounting device having such a structure, the valve plate 46 can be connected to the core by controlling the energization of the coil 36 by the control device 38 according to the driving state of the vehicle detected by the sensor 40. The valve plate 46 is magnetically attached to or separated from the member 66, and due to the magnetic behavior of the valve plate 46, the flow of liquid only through the first orifice 50 and the flow inside the sub-liquid chamber 16 are caused as in the previous embodiment. It is possible to appropriately achieve large viscous damping due to liquid confinement, high spring constant, etc.

Although two embodiments of the present invention have been described in detail above, the present invention is not to be construed as being limited only to these illustrative embodiments, and the present invention is not intended to be interpreted as being limited to these illustrative embodiments. Various changes, modifications, improvements, etc. can be made to the invention.

For example, in the previous example, the sub-liquid chambers 16 were constructed from narrow circular arc portions having a predetermined length that were provided symmetrically within the rubber block 8, but these two sub-liquid chambers 16 could be integrated. Therefore, the pressure receiving chamber 14
There is no problem even if the inner restraining ring 20 is formed inside the rubber block 8 so as to surround the periphery of the pressure receiving chamber 14.Instead of providing the inner restraining ring 20 on the side of the sub-liquid chamber 16, it may be arranged on the inner surface of the rubber block 8 on the side of the pressure receiving chamber 14. It is also possible to set

Further, as shown in FIGS. 4 and 5, a guide pin 70 is erected on the core member 32 to guide the valve plate 46 which is magnetically attached to the electromagnetic means consisting of the core member 32 and the coil 36. It is also possible to magnetically attach and detach the valve plate 46 to and from the core member 32 under the guidance of the guide pin 70. Furthermore, even when the rubber sleeve 42 is provided with the above-mentioned curved In addition to the shape, there is no problem even if it is a straight cylindrical shape as shown in FIG.

Furthermore, the first and second orifices 50, 52
As shown in FIGS. 6 and 7, the formation of the communication path 72 is limited to only forming a communication path 72 with a large cross-sectional area passing through the partition plate 12 and the core member 32, and the communication path 72 is formed in the valve plate 46. A plurality of first through holes 74 having a small cross-sectional area corresponding to the first orifice 50 are provided at opposing positions, while the total cross-sectional area closed by the end face of the core member 32 is large due to magnetic attachment. By providing the second through hole 76, when the valve plate 46 is magnetically attached,
While the first orifice is formed in the first through hole 74, when the valve plate 46 is released from magnetization, the incompressible fluid freely flows through the plurality of second through holes 76. It is also possible to tighten it so that large viscous damping does not occur.

Further, as shown in FIGS. 8 and 9, a communication path 7 passing through the partition plate 12 and the core member 32
2, the through hole 7 provided in the valve plate 46
8 is eccentrically provided, the valve plate 46 comes into contact with the core member 32 due to magnetic attraction, so that the cross-sectional area of the passage becomes smaller in the overlapping portion of the communication passage 72 and the through hole 78, and the One orifice will be formed. Furthermore, when the valve plate 46 having the through hole 78 is not magnetized, the communication passage 72 and the through hole 78 function as a second orifice, and the incompressible fluid between the pressure receiving chamber 14 and the equilibrium chamber 26 is free. distribution is allowed.

Furthermore, in FIG. 10, the core member 3
A groove 80 with a predetermined cross-sectional area is formed on the end surface of the side where the second valve plate 46 comes into contact, and through this groove 80, when the valve plate 46 is magnetized, it connects with the communication path 72 on the partition member side. The through hole 78 on the valve plate 46 side is communicated with a small passage cross-sectional area, thereby forming a first orifice, while a large cross-sectional area is formed when the valve plate 46 is not magnetized. Even a structure in which the area communication path 72 and the through hole 78 serve as a second orifice can be adopted in the present invention.

Furthermore, since a metal valve plate 46 made of a magnetic material is magnetically attached to the electromagnet means consisting of the core member 32 and the coil 36, contact between metals can be eliminated and the orifice can be sealed. In order to enhance the effect, at least one of the opening surfaces of the valve plate 46 and the core member 32 may be made of a rubber polymer material, etc., as long as it does not adversely affect the magnetization operation of the valve plate 46. A buffer material may be provided,
An example is shown in FIG. That is, in FIG. 11, when the rubber sleeve 42 is vulcanized, a rubber layer 82 is formed as a cushioning material layer with a predetermined thickness on the side of the valve plate 46 facing the core member 32.

In addition, in the structure of the above example, when the electromagnetic means is energized (ON), the valve plate 4 which is the operating member
6 is designed to be magnetically attached to the core member 32, but it is also possible to operate the valve plate 46 to be separated from the core member 32 by energizing the coil 36. . This can be done, for example, by using the valve plate 46 as a permanent magnet, while energizing the core member 32 to give it the opposite polarity.

As described above, the present invention can be implemented in various forms, and furthermore, there are various forms other than those exemplified above, and although it is not necessary to exemplify them one by one here, the various embodiments are described below. As long as it does not depart from the spirit of the present invention,
It goes without saying that all of these are included within the scope of the present invention.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing one embodiment of the mounting device according to the present invention, FIG. 2 is a cross-sectional view taken from the side shown in FIG. 1, and FIG. This is a sectional view corresponding to FIG.
The figure is a sectional view of a main part showing another example of the structure of the peripheral part of the partition plate and the valve plate, FIG. 5 is a bottom view of the part shown in FIG. 4, and FIGS. 6 and 8 are respectively shown in FIG. FIG.
7 and 9 are bottom views of FIGS. 6 and 8, respectively, and FIGS. 10 and 11 are sectional views of main parts showing still other different examples in the portion of FIG. 4, respectively. . 2: Mounting bracket, 8: Rubber block, 12: Partition plate, 14: Pressure receiving chamber, 16: Sub-liquid chamber (third liquid chamber), 18: Outer restraint ring, 20: Inner restraint ring, 22: Protective cap, 24 : Diaphragm, 26: Equilibrium chamber, 32: Core member, 36: Coil, 38: Control device, 40: Sensor, 42: Rubber sleeve (supporting means), 46: Valve plate (actuating member), 48: Intermediate chamber, 50 :First orifice,
52: Second orifice, 54: Passage, 56: Through hole, 64: Plate, 66: Core member, 68: Annular rubber, 70: Guide pin, 72: Communication path, 82:
rubber layer.

Claims (1)

[Scope of Claims] 1. An elastic body is provided on one side of the partition member to form a pressure receiving chamber within the elastic body, and an enclosure at least partially made of a flexible thin film is provided on the other side of the partition member. The pressure receiving chamber and the equilibrium chamber are interposed between the vehicle body and the power unit, and the pressure receiving chamber and the equilibrium chamber are filled with a predetermined incompressible fluid. In the mounting device, an orifice mechanism that connects the pressure receiving chamber and the equilibrium chamber and allows selection of a state with a large passage cross-sectional area and a state with a small passage cross-sectional area, the orifice mechanism being provided in the elastic body, A third liquid chamber communicated with the equilibrium chamber, and a large passage cross-sectional area of the orifice mechanism allow communication between the pressure receiving chamber and the equilibrium chamber, and also allow communication between the third liquid chamber and the equilibrium chamber. The pressure receiving chamber and the equilibrium chamber are communicated only by a first operating position that allows fluid flow between the chambers and a state in which the cross-sectional area of the passage of the orifice mechanism is small;
an actuation member that takes two positions, a second actuation position that prevents fluid flow between the third liquid chamber and the equilibrium chamber; and a actuation member that takes the actuation member in one of the two actuation positions. a support means for holding the actuating member in either of the two actuating positions against the retaining action of the support means; A mounting device for a power unit, characterized in that it is provided with electromagnetic means for positioning the power unit at one position and the other. 2. The mounting device according to claim 1, wherein the electromagnetic means includes a core member provided on the side of the equilibrium chamber of the partition member and a coil arranged around the core member. 3. The supporting means is a cylindrical member made of an elastic material and disposed around the electromagnetic means, and the actuating member is attached to an opening of the cylindrical member, and the actuating member is disposed around the electromagnetic means. Claim 1: An intermediate chamber surrounded by the member, the cylindrical member, and the partition member is formed, and a through hole communicating the intermediate chamber and the equilibrium chamber is formed in the actuating member. The mounting device according to item 1 or 2. 4. The support means is an annular member made of an elastic material that is attached to and extends along the periphery of the actuating member, and the outer periphery of the annular member is sealed to the partition member. Accordingly, an intermediate chamber surrounded by the operating member, the annular member, and the partition member is formed in the equilibrium chamber, and a through hole communicating the intermediate chamber and the equilibrium chamber is formed in the operating member. A mounting device according to claim 1 or 2. 5. The mounting device according to claim 3 or 4, wherein the third liquid chamber is communicated with the intermediate chamber and further communicated with the equilibrium chamber via the intermediate chamber. 6. The orifice mechanism is composed of a first orifice with a small passage cross-sectional area and a second orifice with a large passage cross-sectional area, which are separately provided in the partition member, and which The mounting device according to any one of claims 1 to 5, wherein the mounting device is configured so that only the second orifice is opened and closed. 7. While the partition member has a communication passage corresponding to a state where the cross-sectional area of the passage of the orifice mechanism is large, the entrance portion of the communication passage is narrowed by contact with the actuation member, and the passage of the orifice mechanism is narrowed. The mounting device according to any one of claims 1 to 5, wherein a state in which the cross-sectional area is small is formed. 8. The mounting device according to any one of claims 2 to 7, wherein a cushioning material layer having a predetermined thickness is formed on at least one of the facing surfaces of the core member and the operating member. .