JPH0568376B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mounting device for mounting a power unit such as an engine to a base such as a vehicle body. This invention relates to an improvement in which deformations of pairs of mounts placed on both sides of an axis are correlated with each other.

(Prior Art) Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 58-161617, mounting devices of this type have been disposed on both sides of the rotating shaft of a power unit, and each mounted with a compressible fluid. The power unit has an upper chamber and a lower chamber in which the power unit is enclosed, and the legs of the power unit are connected to the partition walls of the upper and lower chambers. The lower chamber, the lower chamber of the left mount, and the upper chamber of the right mount are connected by independent conduits, and in response to bounce vibrations of the power unit, fluid moves between the upper and lower chambers of both mounts, which communicate with each other. There is a known device that achieves low bounce stiffness by using a moving spring constant during the movement, while increasing roll stiffness against roll vibration of the power unit by preventing fluid movement between the upper and lower chambers. ing.

(Problem to be Solved by the Invention) However, since the purpose of this conventional device is essentially to increase the roll rigidity, the high roll rigidity increases the transmission rate of the fluctuating torque of the power unit to the base. , it is difficult to alleviate vibrations, noise, etc.

On the other hand, as a conventional example other than the above, for example, as disclosed in U.S. Pat. In addition to having a configuration having one sealed fluid chamber,
It is known that the fluid chambers of both mounts are communicated with each other through a conduit having an orifice so that transient large torque fluctuations of the power unit are attenuated by the orifice.

By the way, with the aim of reducing the roll rigidity of the mounting device, the present inventors have developed the basic configuration of the latter conventional technology, that is, the fluid chambers of the mount arranged on both sides of the rotation axis of the power unit. As a result of repeated studies on a configuration in which they are connected to each other through a conduit, it was found that due to the resonance phenomenon of the fluid in the conduit, the roll rigidity of the mounting device changes to It was found that the change occurs as shown by the broken line in the figure. In other words, the roll spring constant, which represents the roll stiffness, is approximately equal to the static spring constant K when the fluid chamber is in communication in the low frequency range due to the movement of fluid in the conduit, and decreases as the frequency increases, causing vibration. number a
reaches the minimum value.

When the frequency increases beyond the above minimum frequency a, the inertial force of the fluid in the pipe increases, which is proportional to the square of the acceleration, making it difficult for the fluid to flow through the pipe force, so the vibration increases relatively rapidly. Non-communicating spring constant (1+N)K when the fluid chamber is not communicating with the number e
(N is the expansion/movement spring constant ratio of the elastic wall in the mount).

Even after the frequency e is exceeded, it continues to increase and reaches its maximum value at the natural frequency n of the fluid in the conduit.

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

Considering the above results, when the roll frequency of the power unit is in the low frequency range, the roll stiffness can be reduced, but in the high frequency range, the roll stiffness becomes as high as when it is not connected, and therefore the roll stiffness is always reduced. It will not be possible to keep it low.

The main object of the present invention is to provide a mounting device in which the fluid chambers of both mounts are communicated with each other through a conduit, as described above, in which a part of the wall of the fluid chamber in each mount is made of an elastic membrane. In addition to controlling the deformation of the elastic membrane, by controlling the communication state of the fluid chambers of both mounts with the opening/closing member in the middle of the conduit, the opening/closing member is closed in the high frequency range of the roll vibration mode. In addition, the change in volume of the fluid chamber is absorbed by the elastic membrane by allowing deformation of the elastic membrane, and at the same time, in the low frequency range, the opening/closing member is opened and the deformation of the elastic membrane is restrained, so that the change in volume of the fluid chamber is absorbed between the two mounts. The purpose is to variably control the spring constant of the mount so that the spring characteristics during roll of the power unit can always be kept soft regardless of the high or low frequency by absorbing the fluid movement.

However, in that case, in order to reliably control the deformation of the elastic membrane and the opening/closing of the opening/closing member with a large amount of power, an actuator operated by fluid pressure from a pressure source such as a hydraulic pump or a vacuum pump is used. When starting the power unit, the pressure source such as the pump does not operate sufficiently, making it impossible to obtain sufficient operating pressure for the actuator.
In addition, when the power unit is stopped, the control system that controls the switching valves that switch between supplying or discharging fluid pressure to the actuator may stop operating at the same time as the power unit stops. This means that it is not possible to stably control the deformation of the elastic membrane and the opening/closing control of the opening/closing member when the system is stopped.

Therefore, it is a further object of the present invention to operate the elastic membrane deformation restraining means and the opening/closing member on the safe side where damping force is generated against vibrations of the engine etc. when the power unit is started or stopped. The objective is to suppress excessive vibration of the power unit.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention is arranged on both sides of the rotating shaft of the power unit as described above, and elastically supports the power unit with respect to the base. Supporting mounts are provided, each mount containing an incompressible fluid. In addition, a conduit is formed to communicate the fluid chambers of both mounts to allow movement of fluid and to correlate pressure changes in both fluid chambers, and a conduit forms a part of the wall of each of the fluid chambers to allow fluid movement. An elastic membrane that deforms depending on the temperature is provided. Further, the elastic membrane deformation restraining means for selectively preventing deformation of the elastic membrane, and an opening/closing member disposed in the middle of the conduit for switching the communication state of the fluid chambers of both the mounts, A spring constant variable means for varying a spring constant is provided, and an actuator is provided for operating the spring constant variable means by switching the communication state with a pressure source. and,
A control means is provided for operating the elastic membrane deformation restraining means of the spring constant variable means to a non-restricting position and the opening/closing member to a closed position when the power unit is started or stopped.

(Function) With the above configuration, in the present invention, when the power unit rolls, the communication between the actuator and the pressure source is cut off in the high frequency range where the fluid does not move in the conduit due to an increase in the vibration frequency.
When the function of the elastic membrane deformation restraining means of the spring constant variable means is stopped and the elastic membrane is allowed to deform, the volume change of the fluid chamber of each mount is absorbed by the deformation of the elastic membrane, and the mounting It is possible to maintain low roll stiffness of the device.

In addition, in the low frequency range, by introducing pressure oil into the hydraulic chamber of the actuator for the opening/closing member, the opening/closing member is opened to enable fluid movement in the conduit, and the hydraulic chamber of the actuator for the elastic membrane deformation restraint means is opened. By introducing pressure oil into the mount, the deformation of the elastic membrane is prevented by the elastic membrane deformation restraining means, and the change in volume of the fluid chamber of each mount is absorbed by the fluid moving through the conduit. This makes it possible to keep the roll stiffness low by making full use of the communication effect region where the roll spring constant is minimized, and thus the spring characteristics during roll can always be made soft.

Furthermore, when starting and stopping the power unit, the control means cuts off the communication between the pressure source and the actuator to hold the elastic membrane deformation restraining means in the unrestricted position so that the elastic membrane can deform freely. By holding the opening/closing member in the closed position and operating the actuator to cut off communication between the fluid chambers of both mounts, the rigidity of the mount increases and a damping force is generated against roll vibration, which increases the As a result, excessive vibration of the power unit can be effectively suppressed even if insufficient operating pressure occurs when the power unit is started or valve malfunction occurs when the power unit is stopped.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

Figure 1 shows the 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 an engine as a power unit mounted and supported at the bottom of the engine room of the vehicle body 1; Brackets 3, 3 extending substantially horizontally are integrally protruded, and between the brackets 3, 3 and the vehicle body 1, that is, on both sides of the crankshaft 2a of the engine 2, the engine 2 is positioned relative to the vehicle body 1. A pair of mounts 4, 4 for elastic support are arranged.

Each of the mounts 4 includes a cylindrical case 5 that is fixed to the vehicle body 1 and has an open upper and lower surface, and a rubber member that seals the upper opening of the case 5 and is connected to each of the brackets 3 via connecting bolts 9. The lower opening of the case 5 is sealed by an elastic membrane 7 made of thin rubber, and the case 5, the elastic wall 6, and the elastic membrane 7 form a sealed fluid chamber 8. is formed, and an incompressible fluid (liquid) is sealed within the fluid chamber 8. Therefore, each elastic membrane 7 forms a part of the wall of the fluid chamber 8, and is provided so as to be deformed according to changes in the internal pressure of the fluid chamber 8.

Further, each end of a conduit 10 is connected to the cases 5, 5 of the mounts 4, 4, respectively, and the fluid chambers 8, 8 of both the mounts 4, 4 are communicated with each other through this conduit 10. It is configured to allow movement and to correlate pressure changes in both fluid chambers 8,8.

Further, at an intermediate position of the conduit 10, an on-off valve 14 is provided as an on-off member for switching the communication state of the fluid chambers 8, 8 of the two mounts 4, 4. The on-off valve 14 includes a valve case 11 having a valve seat 11a therein, a valve body 12 that is fitted into the valve case 11 and can be seated on the valve seat 11a.
and a spring 13 that urges the valve body 12 to close.

Furthermore, 15 is a stopper plate that restricts upward deformation of each of the elastic membranes 7 by a predetermined amount or more. Communication holes 15a, 15a, . . . are opened to allow movement.

On the other hand, below the elastic membrane 7, a substantially cup-shaped support plate 16 whose outer edge is fixed to the lower end of the case 5 of the mount 4 is disposed on the vehicle body. A support hole 16a is opened in the support plate 16, and the support hole 16a has an abutment part 17a at the upper end that can come into contact with the elastic membrane 7, and a disk-shaped spring support part 17b at an intermediate position. A formed plunger 17 is fitted and supported so as to be movable in the vertical direction, and the plunger 17 is biased in the downward direction by a spring 17c brought into contact with the spring support portion 17b. When the plunger 17 is positioned at the lower end position by the biasing force of the spring 17c, the distance between the contact portion 17a and the elastic membrane 7 becomes equal to the distance between the stopper plate 15 and the elastic membrane 7. Allowing the deformation of the elastic membrane 7, the plunger 17
When the elastic membrane 7 is lifted up against the urging force of
An elastic membrane deformation restraining means 18 is configured to press against and prevent the deformation. Then,
The opening/closing valve 14 and the elastic membrane deformation restraint means 18 constitute a spring constant variable means 19 for varying the spring constant of the mount 4.

The lower end of the plunger 17 is connected to a diaphragm 20 of a diaphragm actuator 21. Inside the actuator 21,
An atmospheric pressure chamber 21a and a hydraulic chamber 21b are formed by a diaphragm 20, which are divided into upper and lower parts.
3 to a hydraulic pump 24 as a pressure source. Further, a communication pipe 25 that connects the hydraulic chamber 21b to a tank 41 opened to the atmosphere is branched and connected in the middle of the hydraulic pipe 22 that communicates with the hydraulic pressure chamber 21b, and a branch part between the hydraulic pipe 22 and the communication pipe 25. A first switching valve 26 for switching the supply or discharge of hydraulic pressure to the hydraulic chamber 21b is disposed, and the first switching valve 26 controls the hydraulic pressure chambers 21b, 21 of the actuators 21, 21.
The elastic membrane deformation restraining means 18 is actuated by switching the communication state between the hydraulic pump 24 and the hydraulic pump 24.

On the other hand, the valve body 12 of the on-off valve 14 is connected to the rod 1.
Diaphragm actuator 28 via 2a
diaphragm 27. The actuator 28 has an atmospheric pressure chamber 28a and a hydraulic chamber 2 divided into upper and lower parts by a diaphragm 27.
8b, and the atmospheric pressure chamber 28a is connected to the hydraulic pipe 3.
0, and the hydraulic chamber 28b is connected to the accumulator 23 via a hydraulic piping 29.
Further, the communication pipe 2 is located in the middle of the hydraulic piping 29.
A communication pipe 30 communicating with the hydraulic chamber 28b is branch-connected, and a second pipe 30 is connected to the branch part of both the pipes 29 and 30 for switching the supply or discharge of pressure oil to the hydraulic chamber 28b.
A switching valve 31 is provided, and the hydraulic chamber 2 of the actuator 28 is controlled by the second switching valve 31.
The on-off valve 14 is opened and closed by switching the communication state between the hydraulic pump 8b and the hydraulic pump 24.

The first and second switching valves 26, 31
A controller 32 is connected to. The controller 32 includes a rotation sensor 33 that detects the rotation speed of the engine 2 and an accelerator opening sensor 3 that detects the accelerator opening (intake negative pressure) of the engine 2.
4, a shift position sensor 35 that detects the shift position of a transmission equipped on the vehicle, a vehicle speed sensor 36 that detects the running speed of the vehicle, a vibration sensor 37 that detects vibrations such as the roughness state of the engine 2, and a vehicle The outputs from a clutch sensor 38 that detects the ON/OFF state of the clutch are inputted, and the controller 32 determines the driving state of the vehicle based on the detection signals of these sensors 33 to 38, and adjusts the speed according to the driving state. The pressure oil from the hydraulic pump 24 is supplied to the hydraulic chambers 21b of the actuators 21, 21, 28,
21b, 28b, or the hydraulic chamber 21
b, 21b, 28b to the atmosphere through the tank 41, the first and second switching valves 26,
By switching control of 31, plunger 17
and is configured to operate the on-off valve 14.

Therefore, the biasing force of the spring 13 of the on-off valve 14 and the spring 17c of each elastic membrane deformation restraint means 18 causes the plunger 17 of the elastic membrane deformation restraint means 18 to be pressed against the elastic membrane 7 when the engine 2 is started or stopped. On the other hand, a control means is configured to operate the on-off valve 14 to the unrestricted position and to the closed position, respectively.

Note that 39 is a check valve disposed in the hydraulic piping 22, and 40 is a motor for operating the hydraulic pump 24.

Therefore, in the above embodiment, the controller 3
The operating state of the vehicle is determined based on the output signals of the sensors 33 to 38 input to the engine 2, and when the engine 2 is experiencing roll vibration without a large torque being input to the engine 2, the roll vibration is detected. The frequency at is determined. As shown in Figure 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 o, the controller 32
As a result, the second switching valve 31 is controlled to shut off the hydraulic chamber 28b of the actuator 28 and the hydraulic pump 24, and the actuator 28 is kept in a non-operating state.
is closed. At the same time, the first switching valve 26 is controlled to communicate the hydraulic chamber 21b of each actuator 21 with the tank 41, and the hydraulic chamber 21b is opened to the atmosphere.
Each actuator 21 is kept in an inoperative state, and the plunger 17 of the elastic membrane deformation restraint means 18 is
The spring force 7c biases and holds the elastic membrane 7 at a lower end position slightly away from the elastic membrane 7, so that the elastic membrane 7 can be freely deformed. Therefore, roll vibration does not cause fluid movement through the conduit 10 between the fluid chambers 8, 8, but instead each elastic membrane 7 deforms to absorb the volume change of the fluid chamber 8, and As a result, the roll spring constant of the mounting device is K+, which is the static spring constant K plus the membrane stiffness ΔK of the elastic membrane 7.
ΔK remains low regardless of changes in vibration frequency.

On the other hand, in a low frequency range where the roll vibration frequency is below the frequency o, the controller 32 controls the hydraulic chamber 21b of each actuator 21 and the hydraulic pump 2.
The first switching valve 26 is controlled to switch so that the first switching valve 26 communicates with the hydraulic pump 24 in the hydraulic chamber 21b.
Pressure oil is introduced from the air pressure chamber 21a, and as a result, each actuator 21 is activated, and the plunger 17 of the elastic membrane deformation restraining means 18 is moved to the pressure between the atmospheric pressure in the atmospheric pressure chamber 21a and the hydraulic pressure introduced into the hydraulic chamber 21b. Due to the difference, the plunger 17 moves upward against the biasing force of the spring 17c, and as the plunger 17 rises, the elastic membrane 7 is pressed against the stopper plate 15 and its deformation is prevented. Therefore, with the roll vibration of the engine 2, the fluid in both fluid chambers 8, 8 moves through the conduit 10, and the change in volume of the fluid chamber 8 is absorbed by this fluid movement, as indicated by the broken line in FIG. By effectively utilizing the maximum effect range of the frequency characteristics of the mount stiffness in the roll mode shown in FIG. 2, the roll stiffness can be kept extremely low. Therefore, it is possible to reduce the roll rigidity from the low range to the high range of the roll vibration frequency, thereby reducing the transmission rate of the roll vibration of the engine 2 to the vehicle body 1, and reducing vibrations, noise, etc. of the vehicle body 1. .

On the other hand, when a large torque is applied to the engine 2, the controller 32 controls the second switching valve 31 so that the hydraulic chamber 28b of the actuator 28 is opened to the atmosphere via the tank 41.
is controlled to switch, and the on-off valve 14 is closed by the biasing force of the spring 13. At this time, regardless of the level of the roll vibration frequency, there is no movement of fluid through the conduit 10 between the mounts 4, 4, so when the elastic membrane 7 is in a state where it can be freely deformed, the stopper plate 15 or the lowering end position When the elastic membrane 7 is in contact with the plunger 17 located at the lower position or when the deformation of the elastic membrane 7 is prevented by the raised plunger 17, the elastic membrane 7 comes to form a fixed wall due to the restraint by the plunger 17. Therefore, roll rigidity can be kept high.

In this case, the elastic membrane deformation restraining means 18 and the on-off valve 14 are connected to the first and second switching valves 2, respectively.
Hydraulic chambers 21b, 2 in the actuators 21, 28 are drivingly connected to diaphragm type actuators 21, 28 controlled by the actuators 6, 31.
8b, the elastic membrane deformation restraining means 18 and the on-off valve 14 operate stably and reliably with a large force. The operation of allowing or preventing the deformation of the valve 7 and the opening and closing operation of the on-off valve 14 can be reliably performed.

In addition, when the hydraulic pump 24 is not operating sufficiently, such as when starting the engine 2, the actuator 2
1, 21, 28, or when the operation of the first and second switching valves 26, 31 becomes defective, such as when the engine 2 is stopped, the associated operation Due to the decrease in pressure, each plunger 17 is held at a lower end position slightly away from the elastic membrane 7 by the biasing force of the spring 17c, that is, a position where the elastic membrane 7 is not restrained, and the on-off valve 14 is held at the closed position by the biasing force of the spring 13. The spring constant of each mount 4 of the engine 2 is equal to the static spring constant K of the mounting device.
It is increased by adding membrane stiffness ΔK to K + ΔK. As a result, this increase in spring constant generates a damping force against roll vibrations, and excessive vibrations of the engine 2 can be suppressed. In addition, communication ports 15a, 15a, . . . are formed in the stopper plate 11 of the elastic membrane 7 disposed in the fluid chamber 8, so that when fluid passes through the communication ports 15a, 15a, . The damping resistance provides a damping effect against the vibrations of the engine 2, and therefore the damping effect against the vibrations of the engine 2 can be produced even more effectively.

In the above embodiment, the hydraulic pump 24 that supplies pressure oil is used as the pressure source, but the vacuum pump is used to control the introduction or release of negative pressure to each actuator using a switching valve. Furthermore, air may be used as the working fluid of the actuator, and in either case, the same operation and effect as in the above embodiment can be achieved.

In addition, a pressure sensor detects when the engine 2 is started or stopped, and a controller controls each actuator based on the detection signal of the sensor to set the elastic membrane deformation restraining means to the non-restricted position of the elastic membrane, and to set the opening/closing valve to the position where the elastic membrane is not restrained. may be held in the closed position.

(Effects of the Invention) As described above, according to the present invention, fluid-filled mounts are arranged on both sides of the rotating shaft of the power unit, and the fluid chambers of the mounts are communicated with each other through conduits, and the walls of each fluid chamber are A part of the mount is formed of an elastic membrane, and deformation of the elastic membrane of each mount is selectively prevented by actuating an elastic membrane deformation restraining means by an actuator that receives fluid pressure from a pressure source. In addition, in a mounting device in which the communication state of the fluid chambers of both mounts is switched by an opening/closing member provided in the middle of the conduit, when the actuating pressure of the actuator becomes other than a predetermined value, the elastic membrane deformation restraining means is activated. By operating the elastic membrane in the unrestricted position and the opening/closing member in the closed position, the elastic membrane can be restrained and the opening/closing member can be opened/closed stably with a large force from the pressure fluid, while the power unit can be operated stably. By keeping the spring characteristics soft during roll regardless of the high or low frequency, the transmission rate of roll vibration to the base can be reduced, and the vibration and noise of the base can be alleviated, and they can be controlled reliably. In particular, when applied to vehicles, vibrations and noise levels on the vehicle body side can be effectively reduced. In addition, when starting the engine when the operating pressure of the accumulator is insufficient or when the engine is stopped when the operation of the switching valve, etc. that controls the supply of fluid pressure to the accumulator is malfunctioning, the elastic membrane deformation restraining means and the opening/closing member are Since the roll vibration is maintained on the safe side, that is, on the side where a vibration damping effect can be obtained by increasing the mount rigidity, excessive vibration that occurs when starting or stopping the engine can be suppressed.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic explanatory diagram showing the overall configuration, and FIG. 2 is an explanatory diagram showing the vibration frequency characteristics of the roll rigidity. DESCRIPTION OF SYMBOLS 1... Vehicle body, 2... Engine, 2a... Crankshaft, 4... Mount, 7... Elastic membrane, 8... Fluid chamber, 10... Conduit, 14... Open/close valve, 19...
Spring constant variable means, 17...Plunger, 18...
...Elastic membrane deformation restraint means, 21... Actuator, 21a... Atmospheric pressure chamber, 21b... Hydraulic chamber, 2
4... Hydraulic pump, 28... Actuator, 2
8a...atmospheric pressure chamber, 28b...hydraulic chamber.

Claims (1)

[Claims] 1. Mounts are arranged on both sides of the power unit to sandwich the rotating shaft and elastically support the power unit to the base, each mount is filled with an incompressible fluid and the fluid chambers of both the mounts are communicated with each other. a conduit for allowing movement of fluid and relating pressure changes in both fluid chambers; and an elastic membrane forming a part of the wall of each of the fluid chambers and deforming in response to changes in pressure in the fluid chambers. On the other hand, the elastic membrane deformation restraining means for selectively preventing deformation of the elastic membrane, and an opening/closing member arranged in the middle of the conduit and switching the communication state of the fluid chambers of both the mounts, an actuator which is provided with a spring constant variable means that makes the constant variable, and which actuates the spring constant variable means by switching the state of communication with a pressure source; 1. A mounting device comprising: a control means for operating the membrane deformation restraint means in a non-restraint position and the opening/closing member in a closed position.