JPH0637138B2 - 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 a power unit such as an engine on a base such as a vehicle body of a vehicle. 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 mount for elastically supporting the power unit with respect to the base is provided, and the upper chamber of the left mount and the lower chamber of the right mount, and the lower chamber of the left mount and the right mount. The upper chamber is made to communicate with each other 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 of the mount, while the power unit is obtained. With respect to the roll vibration of (1), it is known that the fluid rigidity between the upper and lower chambers is not increased to increase the roll rigidity.

(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 provide a basic configuration of the latter prior art described above, that is, fluid chambers of mounts arranged on both sides of a shaft of a power unit. When various investigations were repeated on the structure in which the conduits are connected, the roll rigidity of the mounting device is shown by the broken line in Fig. 2 in accordance with the change in the frequency due to the torque fluctuation of the power unit due to the resonance development of the fluid in the conduit. 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.

Considering the above results, the roll rigidity can be reduced when the roll frequency of the power unit is in the low frequency range, but in the high frequency range, the roll rigidity is as high as when not in communication, so the roll rigidity is always kept low. You will not be able to.

The present invention has been made by the inventors of the present invention to solve such a problem, and its main purpose is to mount a fluid chamber of both mounts by a conduit as described above. In the device, the rigidity of a part of the wall of the fluid chamber in each mount is set to be partially low, and the deformation of the low-rigidity wall is controlled, so that the fluid chamber in the roll vibration mode in the high frequency region can be controlled. The volume change is absorbed by the low-rigidity wall, and at the same time, the volume change in the low frequency range is absorbed by the fluid movement between both mounts, and the spring characteristics of the power unit during roll are always kept soft regardless of the high or low frequency. To get it.

However, in that case, it is conceivable to use the electromagnetic force of the electromagnet as the actuation source of the means for controlling the deformation of the low-rigidity wall, but when a large vibration force acts on the fluid chamber of the mount, the electromagnetic force generated by the energization of the electromagnet causes With force, the operating force is small,
Therefore, the deformation control of the low-rigidity wall cannot be stably and reliably performed.

Therefore, an object of the present invention is to further utilize the negative pressure of the negative pressure source such as the intake negative pressure in the intake pipe of the engine or the fluid pressure generated by various pressure sources as the operation source, thereby reducing the wall of the low rigidity wall. It is to ensure that deformation control can be obtained with large power.

(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 deforms in accordance with a change in pressure in the fluid chamber, and elastic film deformation restraining means for selectively preventing deformation of the elastic film is provided.

The elastic film deformation restraint means is provided with a plunger member that can contact the elastic film and an actuator that pushes and pulls the plunger member by supplying and discharging the working fluid.

(Operation) With the above configuration, in the present invention, during roll vibration of the power unit, by operating the actuator so that the plunger member separates from the elastic film in the high frequency region where the fluid does not move in the conduit due to the increase in frequency, When the function of the elastic film deformation restraint means is stopped and the elastic film is allowed to deform, the volume change of the fluid chamber of each mount is absorbed by the deformation of the elastic film, and the low roll rigidity can be maintained.

In the low frequency range, when the actuator is actuated to bring the plunger member into contact with the elastic film to prevent its deformation, the volume change of the fluid chamber of each mount is caused by the fluid moving through the conduit. It will be absorbed and the roll rigidity can be kept low by using the communication effect area where the roll spring constant is minimized as it is.
The spring characteristic during rolling can be always softened.

Further, the actuator of the elastic film deformation restraint means is
The negative pressure of the negative pressure source, such as the negative pressure in the intake pipe of the engine, and the fluid pressure generated by various pressure sources are used to push and pull the plunger member. The plunger member can be reliably operated.

(Example) Hereinafter, the Example of this invention is described based on drawing.

FIG. 1 shows an overall configuration of an embodiment applied to mounting a vehicle engine on a vehicle body, 1 is a vehicle body as a base, 2 is a power unit mounted and supported on the bottom of the engine room of the vehicle body 1. In the engine, brackets 3 and 3 extending substantially horizontally are integrally provided on both left and right side surfaces of the engine 2 such that the rotary shaft of the engine 2 is sandwiched between the brackets 3 and 3 and the vehicle body 1. Intermounting mounts 4 and 4 for elastically supporting the engine 2 with respect to the vehicle body 1 are arranged in the space, that is, on both sides of the crankshaft 2a of the engine 2.

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 an elastic wall 6 made of, for example, the lower surface opening of the case 5 is closed by an elastic film 7 made of thin rubber, and the case 5, the elastic wall 6 and the elastic film 7 are formed.
To form a closed fluid chamber 8.
A non-compressible fluid (liquid) is enclosed inside. Therefore, each elastic film 7 forms a part of the wall of the fluid chamber 8,
The fluid chamber 8 is provided so as to be deformed according to changes in the internal pressure.

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. A valve case 11 having a valve seat 11a therein is provided at an intermediate position of the conduit 10.
And the valve seat 11a fitted in the valve case 11.
An on-off valve 14 is provided which includes a valve body 12 that can be seated on and a spring 13 that urges the valve body 12 to close.

Further, 15 is a stopper plate that regulates upward deformation of each elastic film 7 by a predetermined amount or more, and the stopper plate 15 is provided in the fluid chamber 8 and a part thereof does not move the fluid. The permissible communication holes 16, 16, ... Are opened.

On the other hand, below the elastic film 7, a substantially cup-shaped support plate 1 having an outer edge portion fixed to the lower end of the case 5 of the mount 4.
7 is provided on the vehicle body. A support hole 17a is opened in the support plate 17, and the support hole 17a has a contact portion 19a capable of contacting the elastic film 7 at the upper end and a disc-shaped spring support portion 19b at an intermediate position. Plunger 19 formed
Is movably supported in the vertical direction, and the plunger 19 has a spring 1 abutting against the spring supporting portion 19b.
It is urged downward by 9c. When the plunger 19 is positioned at the lower limit value by the urging force of the spring 19c, the distance between the contact portion 19a and the elastic film 7 becomes equal to the distance between the stopper plate 15 and the elastic film 7. The elastic membrane 7 is allowed to deform, and the plunger 19
When the actuator 21 to be described later rises against the urging force of the spring 19c, the elastic film deformation restraining means 18 for pressing the elastic film 7 against the stopper plate 15 by its abutting portion 19a to prevent its deformation. It is configured.

The lower end of the plunger 19 is connected to the diaphragm 20 of the diaphragm actuator 21. Inside the actuator 21, a first negative pressure chamber 21 a and a second negative pressure chamber 21 that are vertically divided by a diaphragm 20 are provided.
b is formed, and the first and second negative pressure chambers 21a and 21b are formed.
Is connected to a vacuum pump 25 as a negative pressure source via negative pressure pipes 22 and 23 via an accumulator 24, respectively. An atmospheric communication pipe 26 that opens the second negative pressure chamber 21b to the atmosphere is branched and connected in the middle of the negative pressure pipe 23 that communicates with the second negative pressure chamber 21b. A first switching valve 27 for switching the introduction of a negative pressure to the second negative pressure chamber 21b or the opening of the atmosphere is provided at a branch portion with respect to 26.

On the other hand, the valve element 12 of the opening / closing valve 14 is connected to the diaphragm 28 of the diaphragm type actuator 29 via the rod 12a. The actuator 29 has a first negative pressure chamber 29a and a second negative pressure chamber 29b which are vertically divided by a diaphragm 28 therein, and the first negative pressure chamber 29a is connected to the negative pressure pipe 22. Second negative pressure chamber 2
9b is connected to the accumulator 24 via a negative pressure pipe 30. Further, an atmosphere communication pipe 31 communicating with the atmosphere communication pipe 26 is branched and connected in the middle of the negative pressure pipe 30, and the second negative pressure chamber 2 is provided at a branch portion of both the pipes 30 and 31.
A second switching valve 32 is provided for introducing a negative pressure to 9b or switching a function of the atmosphere.

The first and second switching valves 27 and 32 are
The controller 33 is connected. The controller 3
3 is a rotation sensor 34 for detecting the rotation speed of the engine 2.
An accelerator opening sensor 35 for detecting an accelerator opening (intake negative pressure) of the engine 2, a shift position sensor 36 for detecting a shift position of a transmission mounted on the vehicle, and a vehicle speed sensor for detecting a traveling speed of the vehicle. 37, a vibration sensor 38 for detecting vibration of the engine 2 such as a roughness state, and a clutch sensor 39 for detecting ON / OFF states of the clutch of the vehicle are input, and these sensors 34 to
Based on the detection signal of 39, the controller 33 applies the negative pressure from the vacuum pump 25 to the actuators 21, 21, 2.
Introduced into the second negative pressure chamber 21b, 21b, 29b of 9 or by switching control the first and second switching valves 27, 32 so as to open the negative pressure chamber 21b, 21b, 29b to the atmosphere, It is configured to operate the plunger 19 and the on-off valve 14.

Incidentally, 40 is a check valve provided in the negative pressure pipe 22, and 41 is a check valve.
Is a filter provided with the atmosphere communicating pipe 26 at the atmosphere opening port.

Therefore, in the above-described embodiment, the driving state of the vehicle is determined based on the output signals of the sensors 34 to 39 input to the controller 33, and the engine 2 rolls in a state where a large torque is not input to the engine 2. When the roll is vibrating, the vibration frequency during the roll vibration is determined. Then, as shown in FIG. 2, the roll frequency corresponds to the static spring constant K when both mounts 4 and 4 are in communication.
In the frequency range higher than fo, the controller 33 causes
The second switching valve 32 is switch-controlled so that the second negative pressure chamber 29b of the actuator 29 is opened to the atmosphere, and the actuator 29 is kept in the operating state, whereby the on-off valve 14 is opened. At the same time, each actuator 2
The first switching valve 27 is switched and controlled so that the first second negative pressure chamber 21b and the vacuum pump 25 communicate with each other, and negative pressure is introduced into the first and second negative pressure chambers 21a and 21b of the actuator 21. As a result, each actuator 21 is kept in the non-actuated state, and the plunger 19 is biased and held at the lower end position slightly apart from the elastic film 7 by the spring force of the spring 19c, so that the elastic film 7 is freely deformed. It will be ready. Therefore, due to the roll vibration, the fluid does not move through the conduit 10 between the fluid chambers 8, and each elastic film 7 is deformed to absorb the volume change of the fluid chamber 8. As a result, the fluid chambers 8, 8 of both mounts 4, 4
Despite being connected by a conduit, 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 regardless of changes in the vibration frequency. .

On the other hand, in the low frequency range where the roll frequency is equal to or lower than the frequency fo, the controller 33 causes each actuator 21
Of the second negative pressure chamber 21b is connected to the atmosphere communication pipe 26 so that the first switching valve 27 is switched and the second negative pressure chamber 21b is opened to the atmosphere. Then, the plunger 19 moves upward against the biasing force of the spring 19c due to the pressure difference between the negative pressure introduced into the first negative pressure chamber 21a and the atmospheric pressure in the second negative pressure chamber 21b, and this plunger 19 Rises, the elastic film 7 is pressed against the stopper plate 15 and its deformation is prevented. Therefore, the fluid in the fluid chambers 8 and 8 moves through the conduit 10 in accordance with the roll vibration of the engine 2, and the change in the volume of the fluid chamber 8 is absorbed by the fluid movement. The roll rigidity can be kept extremely low by effectively utilizing the maximum effect range in the frequency characteristics of the mount rigidity of the roll mode shown. Therefore, from the reduction of the roll vibration frequency, the roll rigidity is reduced over a high range to reduce the transfer rate of the roll vibration of the engine 2 to the vehicle body 1, and the vibration and noise of the vehicle body 1 can be reduced.

On the other hand, when a large torque is applied to the engine 2, the controller 33 causes the actuator 29 to operate.
The second negative pressure chamber 29b and the vacuum pump 25 are communicated with each other, the second switching valve 32 is switched and controlled, and the spring 13
The on-off valve 14 is closed by the urging force of. At this time, each mount 4, regardless of the roll vibration frequency
Since there is no movement of fluid through the conduit 10 between the four, when the elastic membrane 7 is freely deformable, by contact with the stopper plate 15 or the plunger 19 at the lower end position, or by the raised plunger 19. When the elastic film 7 is prevented from being deformed, each elastic film 7 forms a fixed wall by the restraint by the plunger 19, so that the roll rigidity can be kept high.

In this case, the elastic film deformation restraint means 18 and the opening / closing valve 14 are drivingly connected to the diaphragm type actuators 21 and 29 controlled by the first and second switching valves 27 and 32, respectively.
Since the negative pressure chambers 21b and 29b are actuated by introducing a negative pressure or opening the atmosphere, the elastic membrane deformation restraint means 18 and the on-off valve 14 are stably actuated with a large force. Therefore, the operation of allowing or preventing the deformation of the elastic film 7 and the opening / closing operation of the opening / closing valve 14 can be reliably performed.

Although the vacuum pump 25 is used as the negative pressure source in the above-described embodiment, the vehicle is usually provided with a portion or a device where a negative pressure is generated, such as an intake negative pressure in the intake pipe of the engine. If it is directly used as a negative pressure source, there is an advantage that the device can be simplified and the cost can be reduced.

Although the negative pressure type actuator 21 is used in the above embodiment, the plunger 19 may be driven by using an actuator that operates by introducing a fluid pressure from a pressure source such as an air pump or a hydraulic pump. The same effects as those of the above 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 and preventing the deformation of the elastic film by the plunger member driven by the actuator of the elastic film deformation restraining means,
While restraining the elastic membrane stably and reliably, during roll vibration of the power unit, the volume rigidity of each fluid chamber in the high frequency range is absorbed by the deformation of the elastic membrane to lower the roll rigidity and reduce the low frequency range. The volume change of the power unit can be absorbed by the fluid movement between the two fluid chambers to keep the low roll rigidity. Therefore, the spring characteristic of the power unit during roll is always kept soft regardless of the frequency level, and it can be used as the base of the roll vibration. It is possible to reduce the transmissibility of the base, reduce the vibration and noise of the base, and reliably control the vibration, and to effectively reduce the vibration and noise level on the vehicle body side especially when applied to the vehicle. You can

[Brief description of drawings]

The drawings show the embodiments of the present invention. FIG. 1 is a schematic explanatory view showing the entire structure, and FIG. 2 is an explanatory view showing vibration frequency characteristics of the roll rigidity. 1 ... Body, 2 ... Engine, 2a ... Crankshaft, 4
...... Mount, 7 ... Elastic membrane, 8 ... Fluid chamber, 10 ...
Conduit, 18 ... Elastic membrane deformation restraint means, 19 ... Plunger, 21 ... Actuator, 21a ... First negative pressure chamber,
21b ... second negative pressure chamber, 25 ... vacuum pump.

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. And a conduit for communicating the fluid chambers with each other to allow the movement of the fluid and associating the pressure change between the two fluid chambers with a part of the wall of each fluid chamber, which is deformed according to the change in the fluid chamber pressure. An elastic film and elastic film deformation restraint means for selectively preventing deformation of the elastic membrane, wherein the elastic membrane deformation restraint means includes a plunger member capable of contacting the elastic film and a pusher for pushing the plunger member. A mounting device for a power unit, comprising: an actuator that draws by supplying and discharging a working fluid.