JPH0637133B2 - Power unit mounting device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting device for mounting an engine and a power unit to a base such as a vehicle body of a vehicle, and more particularly, to a rotary shaft of the power unit. The present invention relates to an improvement in which deformations of paired mounts arranged on both sides are associated with each other.

(Prior Art) Conventionally, as a mounting device of this type, as disclosed in, for example, Japanese Patent Application Laid-Open No. 58-161617, it is arranged on both left and right sides of a power unit with a rotating shaft interposed therebetween. With the enclosed upper and lower chambers,
A leg of the power unit is connected to the partition walls of the upper and lower chambers, and a pair of mounts that elastically support the power unit with respect to the base are provided, and an upper chamber of the left mount and a lower chamber of the right mount, and a lower chamber and a right mount of the left mount. The upper chambers are connected by independent conduits, and for the bounce vibration of the power unit, low bounce rigidity is obtained by the moving spring constant when the fluid moves between the upper and lower chambers communicating with each other on both mounts. With respect to roll vibration of the power unit, it is known that the roll rigidity is increased by not moving the fluid between the upper and lower chambers.

(Problems to be solved by the invention) However, in this conventional one, since the purpose is essentially to increase the roll rigidity, the high roll rigidity increases the transmissibility of the fluctuation torque of the power unit to the base, It is difficult to reduce vibration and noise.

On the other hand, as a conventional example other than the above, for example, US Pat.
As disclosed in Japanese Patent No. 705118, each of the mounts arranged on both sides of the rotation axis of the power unit as described above is configured to have one fluid chamber in which an incompressible fluid is enclosed, and It is known that a transient large torque fluctuation of a power unit is attenuated by an orifice by connecting a fluid chamber of a mount with a conduit having an orifice.

By the way, for the purpose of reducing the roll rigidity of the mounting device, the inventors of the present invention have a basic configuration of the latter prior art, that is, a fluid chamber of mounts arranged on both sides of a rotating shaft of a power unit. When various studies were repeated on the structure in which the pipes communicate with each other, the roll rigidity of the mounting device changed to a curve in Fig. 2 according to the change in the frequency due to the torque fluctuation of the power unit due to the resonance phenomenon of the fluid in the pipe. It was found that it changes as shown by. That is, the roll spring constant representing the roll rigidity is (I) in the low frequency range, almost equal to the static spring constant K when the fluid chamber is in communication because the fluid moves in the conduit, and decreases as the frequency increases. The minimum value is reached at the frequency fa.

(II) When the frequency increases beyond the above-mentioned minimum frequency fa, the fluid becomes difficult to flow in the conduit due to the increase of the inertial force of the fluid in the conduit that is proportional to the square of the acceleration. It becomes equal to the non-communication spring constant (1 + N) K (N is the expansion / movement spring constant ratio of the elastic wall in the mount) when the fluid chamber is not in communication at the frequency fe.

(III) It further increases beyond the above-mentioned frequency fe and reaches the maximum value at the natural frequency fn of the fluid in the conduit.

(IV) In a frequency range higher than the natural frequency fn, the frequency decreases as the frequency increases, and gradually approaches the non-communication spring constant (1 + N) K in the state where the fluid does not flow in the conduit.

In consideration of the above results, the roll rigidity can be reduced when the roll frequency of the power unit is at a low frequency, but in the high frequency range, the roll rigidity is as high as when not in communication, so keep the roll rigidity low at all times. Will not be possible.

The present invention has been made by the inventors of the present invention to solve such a problem, and an object of the present invention is to mount a mounting device in which fluid chambers of both mounts are connected by a conduit as described above. In, by setting the rigidity of a part of the wall of the fluid chamber in each mount lower than the elastic wall for supporting the power unit, the volume change of the fluid chamber in the high frequency range of the roll vibration mode is absorbed by the low-rigidity wall, At the same time, the volume change due to the static torque displacement is absorbed by the fluid movement between both mounts, so that the spring characteristic of the power unit during roll can always be kept soft.

(Means for Solving the Problem) In order to achieve the above object, a solution means of the present invention is to provide an incompressible fluid for elastically supporting a power unit on a base on both sides of a rotation shaft of a power unit. A pair of mounts in which the above are enclosed are disposed, and fluid conduits of the both mounts are communicated with each other to allow movement of fluid and to provide a conduit for associating a pressure change in both fluid chambers.

Further, a part of the wall of each of the fluid chambers is formed of an elastic film that is deformed in accordance with a change in the fluid chamber pressure when the power unit has a predetermined roll frequency or higher.

(Operation) With the above configuration, in the present invention, when the roll frequency of the power unit is equal to or higher than the predetermined value, the volume change of the fluid chamber of each mount is absorbed by the deformation of the elastic film. Therefore, low roll rigidity can be maintained even in a high frequency range where fluid does not move in the conduit due to an increase in roll frequency, and roll vibration can be reduced in a wide range of frequency ranges.

Also, when a large static torque is applied to the power unit, the volume change of the fluid chamber of each mount is absorbed by the fluid moving through the conduit, and the elastic membrane is kept in the same state as when there is no load. The rigidity can be kept low, so that the spring characteristics at the time of rolling can be always softened.

First Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an overall configuration of a first embodiment applied when mounting a vehicle engine on a vehicle body, 1 is a vehicle body as a base, and 2 is a power unit mounted and supported on the bottom of the engine room of the vehicle body 1. Engine as
Brackets 3, 3 extending in a substantially horizontal direction are integrally projectingly provided on both left and right side surfaces of the rotation axis of the engine 2, that is, the crankshaft 2a, and between the brackets 3, 3 and the vehicle body 1, that is, the engine 2 Paired mounts 4 and 4 for elastically supporting the engine 2 with respect to the vehicle body 1 are arranged on both sides of the crankshaft 2a.

Each of the mounts 4 is fixed to the vehicle body 1 and has a cylindrical case 5 whose upper and lower surfaces are open, and a rubber which seals the upper opening of the case 5 and is connected to the brackets 3 through connecting bolts 9. And the elastic wall 6 made of, for example, the lower surface opening of the case 5 is sealed by an elastic film 7 made of rubber or the like having a thickness smaller than that of the elastic wall 6.
A closed fluid chamber 8 is formed by the elastic film 7 and an incompressible fluid (liquid) is enclosed in the fluid chamber 8.
Therefore, each elastic film 7 forms a part of the wall of the fluid chamber 8 and is provided so as to be deformed according to the change in the internal pressure of the fluid chamber 8 when the roll frequency of the engine 2 is equal to or higher than a predetermined value. There is.

In addition, the conduits 10 are provided in the cases 5 and 5 of the mounts 4 and 4, respectively.
Are connected to each other, and the conduit 10 connects the fluid chambers 8 and 8 of the mounts 4 and 4 with each other to allow the movement of the fluid and associate the pressure change of the fluid chambers 8 and 8. Is configured.

Reference numerals 11 and 12 denote stopper plates for restricting the vertical deformation of the elastic films 7 by a predetermined amount or more. The upper stopper plate 11 is provided in the fluid chamber 8 and a part of the stopper plate 11 does not move fluid. Allowable communication holes 13, 13, ...
On the other hand, a closed air chamber 14 is formed between the lower stopper plate 12 and the elastic film 7 while being opened. Further, reference numeral 15 is an orifice arranged at an intermediate position of the conduit 10.

Therefore, in the above-described embodiment, since the wall of the fluid chamber 8 in each mount 4 is partially formed by the elastic film 7 having low rigidity, the crankshaft 2 accompanying the operation of the engine 2
When the volume of each fluid chamber 8 changes due to the roll vibration around a, the fluid does not move through the conduit 10 between the fluid chambers 8 and 8, and instead each elastic membrane 7 is deformed and the fluid chamber is deformed. It comes to absorb the volume change of 8. As a result, the second
As shown by the solid line in the figure, despite the fact that the fluid chambers 8, 8 of both mounts 4, 4 are connected by the conduit 10,
The roll spring constant of the mounting device becomes K + ΔK, which is the static spring constant K plus the film rigidity ΔK of the elastic film 7, and is kept low irrespective of the change in the vibration frequency. By reducing the transfer rate of roll vibration to the vehicle body 1, it is possible to reduce the level of vehicle body vibration and muffled sound in the vehicle compartment when the engine 2 is idling or at low speed.

In addition, the fluid chambers 8 and 8 of the left and right mounts 4 and 4 are connected to the conduit 10.
When the volume of each fluid chamber 8 changes due to the large static torque T ₀ applied to the mounting device by the torque reaction force of the engine 2 such as when accelerating in the low gear of the vehicle, both fluid chambers are communicated with each other. 8 and 8 fluids are conduits 10
The elastic film 7 is kept in the same state as when there is no load, because the volume change of the fluid chamber 8 is absorbed by the movement of the fluid. Therefore, when the fluid chambers 8, 8 of both mounts 4, 4 are not communicated with each other by the conduit 10, the elastic film 7 causes the stopper plate 1 to move when the same static torque T ₀ is applied.
While the roll rigidity increases as shown in FIG. 3A by hitting Nos. 1 and 12, the roll rigidity can be kept low as shown in FIG. 3B by the neutral state of the elastic film 7, so that the static torque displacement is reduced. Even at times, it is possible to reduce the vehicle body vibration and noise.

Further, when the torque largely changes during a sudden acceleration / deceleration of the vehicle or during a gear shift, each elastic film 7 is deformed due to a delay in the temporal movement of the fluid in the conduit 10 during a transition until the torque reaches a steady state. Then, the stopper plates 11 and 12
After contact with the fluid, the fluid flows in the conduit 10 and the fluid chambers 8, 8
Since it moves between the rolls, the roll rigidity can be increased, and excessive movement of the engine 2 can be damped and regulated to reduce vibrations and shocks. At that time, since the orifice 15 is arranged in the middle of the conduit 10, the delay of movement of the fluid can be promoted and the above effect can be more remarkably obtained.

In addition, the volume change of the fluid chamber 8 in each mount 4 is absorbed by the deformation of each elastic film 7 during the vertical vibration due to the unbalance in the engine 2 or the traveling vibration of the vehicle, as in the roll vibration mode. It Therefore, it is possible to keep the bounce rigidity of the mounting device low and reduce the transmissibility of the bounce vibration of the engine to the vehicle body 1.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention, in which an opening / closing valve 16 is provided in place of the orifice 15 in the first embodiment.

That is, in this embodiment, the electromagnetic opening / closing valve 16 is arranged at an intermediate position of the conduit 10 that connects the mounts 4 and 4. The electromagnetic on-off valve 16 is connected to the conduit 10, has a valve case 17 having a valve seat 17a therein, a valve body 18 fitted into the valve case 17 and seatable on the valve seat 17a, and the valve. A spring (not shown) for urging the body 18 to open the valve and an electromagnet 19 for attracting the valve body 18 in the valve closing direction against the urging force of the spring are provided. In the above description, a spring (not shown) is used to urge the valve body 18 to open, but a spring that urges the valve body 18 to close and a valve opening direction against the urging force of the spring are used. It may be of a type including an electromagnet 19 for attracting to. The positional relationship of the valve element 18 with respect to the valve seat 17a is determined by the engine 2 due to the torque reaction force when the vehicle moves forward.
In the figure, when the roll is rotated in the clockwise direction, the valve body 18 in the valve closed state has the valve seat 1
It is set so as to be closely contacted with 7a. Others are the same as in the first embodiment.

Therefore, in this embodiment, when the electromagnetic opening / closing valve 16 is opened, the roll rigidity for a roll having a small amplitude under the static torque T ₀ load is always low as shown in FIG. 3B, as in the first embodiment. However, when the opening / closing valve 16 is closed and fluid movement between the mounts 4 and 4 is restricted, when a large static torque T ₀ is applied, the elastic film 7 of each mount 4 contacts the stopper plate 11 (12). As a result, a fixed wall is formed to increase the roll rigidity as shown in FIG. 3A.
Therefore, the above-mentioned two types of spring characteristics can be selected by opening / closing the open / close valve 16 according to the operating state of the vehicle.
There is an advantage that desired characteristics can be obtained.

Further, since the on-off valve 16 is set so that the closing force of the valve body 18 is increased by the torque reaction force when the vehicle travels frequently, which is generated frequently, the supply current to the electromagnet 19 when the valve is closed can be small. There is an advantage that the electromagnet 19 can be made small with a low suction ability.

In each of the above embodiments, each mount 4 is provided with the air chamber 14 that is hermetically sealed, but an opening may be formed in the lower stopper plate 12 so that the air chamber 14 communicates with the atmosphere. The same effect as the example can be obtained.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention. In the second embodiment, the on-off valve 16 is provided on the vehicle body 1 side, while the engine 2
It is provided on the side.

That is, in this embodiment, the oil passage 9'a is formed through the connecting bolt 9'connected to the elastic wall 6 of each mount 4, and each end of the conduit 10 is connected to the oil passage 9'a. An on-off valve 16 arranged at an intermediate position of the conduit 10 is attached to the engine 2 side. Others are the same as those in the second embodiment. Therefore, also in this embodiment, the same operational effects as those of the second embodiment can be obtained.

(Effects of the Invention) As described above, according to the present invention, the fluid-sealed mounts are arranged on both sides of the rotating shaft of the power unit, the fluid chambers of the mounts are connected by the conduits, and the wall of each fluid chamber is connected. By forming a part of the elastic film that deforms at a roll frequency of the power unit above a predetermined value, the volume change of each fluid chamber due to the roll vibration of the power unit is absorbed by the deformation of the elastic film to lower the roll rigidity. The volume change due to the static torque displacement of the fluid chamber can be absorbed by the fluid movement between the two fluid chambers to maintain the low roll rigidity. Therefore, the spring characteristics are always kept soft over a wide frequency range when the power unit is rolled. The transfer rate of the roll vibration to the base can be reduced, and the vibration and noise of the base can be mitigated. Especially when applied to a vehicle, the vibration and noise level of the vehicle body side can be reduced. Can be effectively reduced.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a schematic explanatory view showing the overall configuration of the first embodiment, FIG. 2 is an explanatory view showing vibration frequency characteristics of the roll rigidity, and FIG. 3 is the same. It is explanatory drawing which shows the characteristic of roll rigidity change at the time of static torque displacement. FIG. 4 is a view corresponding to FIG. 1 showing the second embodiment. FIG. 5 is a view corresponding to FIG. 1 showing the third embodiment. 1 ... Body, 2 ... Engine, 2a ... Crankshaft, 4
...... Mount, 7 ... Elastic membrane, 8 ... Fluid chamber, 10 ...
Conduit, 11, 12 ... Stopper plate, 14 ... Air chamber, 15 ... Orifice, 16 ... Open / close valve.

Claims (1)

[Claims] 1. A mount which is arranged on both sides of a rotation shaft of a power unit and elastically supports the power unit with respect to a base, and each mount has an incompressible fluid sealed therein. The fluid chambers are connected to each other to allow the movement of fluid and form a part of the wall of each fluid chamber with a conduit for associating the pressure change of both fluid chambers. A mounting device for a power unit, comprising: an elastic film that deforms according to a change in pressure in the fluid chamber.