JPH0544369B2 - - 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 a shaft are correlated with each other.

(Prior Art) Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 58-161617, this type of mounting device has been disposed on both the left and right sides of the power unit, with each mounting device being non-compressible. It has upper and lower chambers filled with fluid, the legs of the power unit are connected to the partition walls of the upper and lower chambers, and it has opposing mounts that elastically support the power unit with respect to the base, and includes an upper chamber of the left mount and a right mount. Also, the lower chamber of the left mount and the upper chamber of the right mount are communicated with each other through independent conduits.In response to bounce vibrations of the power unit, the upper and lower chambers of both mounts communicate with each other. Low bounce rigidity is obtained by the movement spring constant when the fluid moves, while roll rigidity is increased by preventing fluid movement between the upper and lower chambers in response to roll vibration of the power unit. something is known.

(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 these parts are connected to each other through a conduit, we found that due to the resonance phenomenon of the fluid within the conduit, the roll rigidity of the mounting device changes to It was found that the change occurs as shown by the curve 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. It reaches its minimum value at frequency fa.

) When the frequency increases beyond the above minimum value frequency fa, the inertial force of the fluid in the conduit increases, which is proportional to the square of the acceleration, making it difficult for the fluid to flow in the conduit, so the frequency increases relatively rapidly. Non-communicating spring constant (1+N)K when the fluid chamber is non-communicating at frequency fe
(N is the expansion/movement spring constant ratio of the elastic wall in the mount).

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

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

Therefore, in order to reduce the roll stiffness of the mounting device, it is necessary to reduce the spring constant in the adverse effect region where the roll frequency of the power unit is near the natural frequency fn.

As described above, an object of the present invention is to provide a mounting device in which the fluid chambers of both mounts on the sides of a power unit are communicated with each other through a conduit.
By controlling fluid movement in the conduit, the purpose is to reduce the spring constant in the adverse effect range of the roll frequency.

(Means for Solving the Problem) In order to achieve the above object, the solution of the present invention is to arrange mounts for elastically supporting the power unit on the base on both sides of the rotating shaft of the power unit. and each mount has a fluid chamber containing an incompressible fluid.

Further, a conduit is provided to communicate the fluid chambers of both mounts to allow movement of fluid and to correlate pressure changes in both fluid chambers.

Furthermore, a flow rate variable means is installed in the conduit to reduce the flow rate of the fluid flowing in the conduit in a frequency range where the roll stiffness of the power unit of the mounting device increases due to the resonance phenomenon that occurs when the fluid flows in the conduit. do.

(Function) With the above configuration, in the present invention, the roll frequency of the power unit is lower than the frequency corresponding to the non-communicating spring constant when the fluid chambers are not communicating, and the mounting is caused by the resonance phenomenon accompanying the fluid flow in the conduit. When the roll rigidity of the rolling device is low, the flow rate variable means is controlled so that the flow rate of the fluid in the conduit becomes large. Then, the fluid moves within the conduit without resistance as the roll vibrates, keeping the spring constant low.

On the other hand, in a frequency range where the roll vibration frequency is higher than the frequency corresponding to the non-communicating spring constant and the roll stiffness increases, the flow rate variable means is controlled so that the flow rate of the fluid in the conduit becomes small. Ru. As a result, the fluid movement within the conduit is damped by the flow resistance, so that the spring constant can be reduced in the adverse effect region near the natural frequency. Therefore, the roll rigidity of the mounting device can be lowered over the entire range of the roll frequency of the power unit.

(First Embodiment) Hereinafter, embodiments of the present invention will be described based on the drawings.

FIG. 1 shows the overall configuration of a first embodiment applied to mounting a vehicle reciprocating engine on a vehicle body, where 1 is a vehicle body as a base, and 2 is a vehicle body 1.
This is an engine as a power unit that is mounted and supported at the bottom of the engine room of the engine 2, and brackets 3, 3 extending in a substantially horizontal direction are integrally formed on both the left and right sides of the engine 2, which sandwich the rotating shaft, that is, the crankshaft 2a. Between the brackets 3, 3 and the vehicle body 1, that is, on both sides of the crankshaft 2a of the engine 2, there are paired mounts 4, 4 for elastically supporting the engine 2 with respect to the vehicle body 1. It is located.

Each of the mounts 4 includes a bottomed cylindrical case 5 that is fixed to the vehicle body 1 and has an open upper surface, and the upper opening of the case 5 is sealed, and is connected to each of the brackets 3 via connecting bolts 8. The case 5 includes an elastic wall 6 made of rubber or the like.
One sealed fluid chamber 7 in which an incompressible fluid (liquid) is sealed is formed.

Further, each end of a conduit 9 is connected to the cases 5, 5 of the mounts 4, 4, respectively, and this conduit 9 connects the fluid chambers 7, 7 of both the mounts 4, 4.
They are configured to communicate with each other to allow movement of fluid, and to correlate pressure changes in both fluid chambers 7, 7.

In addition, a conduit 9 that communicates both the mounts 4, 4 is provided.
At an intermediate position, there is a variable orifice 1 as a flow rate variable means for varying the flow rate of the fluid flowing inside the conduit 9.
0 is placed. As shown in enlarged detail in FIGS. 2 and 3, the variable orifice 10 has a cylindrical sealed case 11 that communicates with the conduit 9, and is rotatably and liquid-tightly fitted into the case 11, and is connected to the conduit 9. an open hole 12 having a hole diameter equivalent to the inner diameter of the open hole 1;
2, a cylindrical rotating body 14 in which orifice holes 13 having a diameter smaller than 2 are opened to intersect with each other;
The electric actuator 16 rotates to switch communication between the conduit 9 and the open hole 12 or the orifice hole 13.

Furthermore, a controller 17 for controlling the operation of the actuator 16 is connected to the actuator 16 of the variable orifice 10, and the controller 17 includes a rotation sensor 18 for detecting the rotation speed of the engine 2, and a rotation sensor 18 for detecting the rotation speed of the engine 2, and a rotation sensor 18 for detecting the rotation speed of the engine 2. an accelerator opening sensor 19 that detects negative intake pressure), a shift position sensor 20 that detects the shift position of the vehicle's transmission, a vehicle speed sensor 21 that detects the vehicle's running speed, and vibrations such as the roughness state of the engine 2. The vibration sensor 22 detects the
Each output from a clutch sensor 23 that detects the ON/OFF state is input, and these sensors 18 to
The controller 17 determines the operating state of the vehicle based on the detection signal of the variable orifice 10, and accordingly rotates the rotating body 14 of the variable orifice 10 to automatically establish communication between the open hole 12 or the orifice hole 13 and the conduit 9. A frequency range in which the roll rigidity of the mounting device relative to the engine 2 is increased due to a resonance phenomenon that occurs when the fluid flows in the conduit 9 by switching control;
In other words, in the frequency range above the frequency fe corresponding to the non-communicating spring constant (1+N)K when the fluid chambers 7, 7 of both mounts 4, 4 are in a non-communicating state, the rotating body 1
The orifice holes 13 of 4 are connected to the conduit 9 and are configured to reduce the flow rate of fluid flowing within the conduit 9.

Therefore, in the above embodiment, the controller 17 receives the detection signals from each of the sensors 18 to 23.
As a result, the lowest order component of the torque fluctuation of engine 2 (for example, the second order component in a 4-cycle 4-cylinder engine)
The roll vibration frequency is detected, and as shown by the solid line in FIG. When the frequency is lower than fe, the open hole 12 of the variable orifice 10 is communicated with the conduit 9, and when the frequency is higher than the frequency fe, the small diameter orifice hole 13 is communicated with the conduit 9. As a result, in the low frequency range lower than the frequency fe, the fluid moves within the conduit 9 without resistance, so the communication effect of lowering the roll spring constant is still obtained, while in the frequency range higher than the frequency fe. , the fluid movement within the conduit 9 is attenuated by the orifice resistance from the orifice hole 13, so the spring constant does not increase in the adverse effect region near the natural frequency fn as in the case of communication, and the spring constant becomes The non-communicating spring constant (1+N) decreases as it approaches K. Therefore, it is possible to reduce the overall roll stiffness, lower the transmission rate of roll vibration of the engine 2 to the vehicle body 1, and alleviate vibrations and noise in the vehicle body 1.

Also, based on the engine speed detected by sensors 18 to 23, accelerator opening (intake negative pressure), transmission shift position, vehicle speed, vibration state such as roughness of engine 2, and ON/OFF state of the clutch. The generated torque of the engine 2 is detected, and when the generated torque is equal to or greater than a set value, the orifice hole 13 of the variable orifice 10 is communicated with the conduit 9 in the same manner as described above. By communicating the orifice hole 13 with the conduit 9, orifice resistance is generated and fluid movement is attenuated, and the roll damping coefficient is increased compared to the value at the time of communication, and as a result, when a large transient torque is generated, Excessive motion of the engine 2 can be restricted to alleviate interference with other members, transient vibrations, and shocks.

Note that the open hole 1 in the variable orifice 10
2 or the orifice hole 13 to the conduit 9 can also be performed by manual operation by a vehicle occupant.

(Second Embodiment) FIG. 5 shows a second embodiment of the present invention.
In the embodiment, the switching of the fluid flow rate in the conduit 9 is controlled from the outside of the conduit 9 by the variable orifice 10, but when the roll frequency of the engine 2 is in the adverse effect range, the vibration amplitude is changed accordingly. By focusing on the fact that the amplitude increases, this change in amplitude is used to automatically switch the fluid flow rate.

That is, in this embodiment, a movable orifice 24 as a flow rate variable means is disposed in the middle of a conduit 9 that communicates the fluid chambers 7, 7 of both mounts 4, 4. The movable orifice 24 has a sealed case 26 forming a valve chamber 25 communicating with the conduit 9, and is loosely fitted into the valve chamber 25 and has an orifice hole 27 of a predetermined diameter opened therein. ，
It consists of a movable plate 28 that moves due to the difference in fluid pressure between the four fluid chambers 7, 7. The case 26 is formed with stopper parts 29, 29 that restrict the reciprocating movement of the movable plate 28 by a set range ±δ with respect to its rest position. When the movable range of the movable plate 28 by the stoppers 29, 29 is smaller than ±δ, the movable plate 28 is moved together with the fluid, but when the amplitude of the fluid exceeds the movable range ±δ of the movable plate 28, the stopper portion 29 , 29 restricts the movement of the movable plate 28, and causes fluid to flow through the orifice hole 27 of the movable plate 28 whose movement is restricted, thereby generating orifice resistance of the fluid and damping roll vibration. and,
As shown in FIGS. 6a and 6b, the movable range |δ| of the movable plate 28 is determined by the opposite effect range (natural frequency fn In order to reduce the spring constant near the natural frequency fn, the spring constant is set to an optimal value that is smaller than the amplitude of the fluid in the conduit 9, which reaches its maximum at the natural frequency fn, and larger than the amplitude of the fluid in the extremely low frequency region. ing.

Therefore, in this embodiment, when the engine 2 rolls vibrates, the frequency of the fluid in the conduit 9 is low, and the amplitude of the fluid in the movable plate 28 in the movable orifice 24 is low.
When the movable plate 28 is in the communication effect range smaller than the movable range ±δ, the movable plate 28
Since it moves freely without being restricted by the movement, orifice resistance to fluid movement does not occur, and it is possible to obtain the same low roll rigidity as when the conduit 9 is open.

On the other hand, in an adverse effect region where the frequency of the fluid increases and its amplitude increases beyond the movable range ±δ of the movable plate 28, the movable range ±δ of the movable plate 28 is exceeded.
The above movement is regulated by the stoppers 29, 29, and the fluid in the conduit 9 flows through the orifice hole 27 of the movable plate 28 whose movement is regulated, so orifice resistance occurs in the movement of the fluid. This orifice resistance can attenuate the fluid resonance phenomenon and reduce roll rigidity.

Furthermore, when the engine 2 generates a large transient torque, the fluid in the conduit 9 moves by a large amount, so the movable plate 28 moves as in the above case.
Due to the restriction of movement by the stopper parts 29, 29, orifice resistance is generated, and therefore, excessive movement of the engine 2 can be prevented by increasing roll damping.

In this case, the movable plate 28 automatically moves to the stopper portion 2 in response to an increase in the vibration amplitude of the fluid in the conduit 9.
9 and 29, there is an advantage that automatic switching of roll damping can be performed with a simpler structure than in the first embodiment.

In the above embodiment, the movable plate 28 of the movable orifice 24 is loosely fitted into the case 26, but as shown in FIG. It may be movably supported by a holding rubber 30 having a shape. Further, in the above embodiment, a movable orifice 2 is provided in the middle of the conduit 9.
However, as shown in FIG. 8, a movable orifice 24'' may be provided at the connection portion of the conduit 9 to one of the mounts 4. In either case, the same effect as in the above embodiment is obtained. It can be effective.

(Third Embodiment) FIG. 9 shows a third embodiment of the present invention, which is similar to the first embodiment described above.
In the embodiment, the variable orifice 10 was provided on the vehicle body 1 side, whereas it was provided on the engine 2 side.

That is, in this embodiment, an oil passage 8'a is formed through the connecting bolt 8' connected to the elastic wall 6 of each mount 4, and each end of the conduit 9 is connected to the oil passage 8'a. A variable orifice 10 disposed at an intermediate position of the conduit 9 is attached to the engine 2 side. The rest of the structure is the same as that of the first embodiment. Therefore, this embodiment can also achieve the same effects as the first embodiment.

(Effects of the Invention) As explained above, according to the present invention, fluid-filled mounts having one fluid chamber and elastically supporting the power unit on the base are arranged on both sides of the rotating shaft of the power unit, The fluid chambers of both mounts are communicated with each other by a conduit, and in the frequency range where the roll stiffness of the power unit increases due to the resonance phenomenon that occurs when the fluid flows in the conduit, the flow rate of the fluid flowing in the conduit is reduced. By providing the variable means, when the power unit rolls vibrates, the roll spring constant, which increases in the adverse effect region near the natural frequency of the fluid in the conduit, is suppressed by the damping resistance provided by the flow rate variable means, and the overall roll stiffness is reduced. It is possible to maintain a low level of vibration, reduce the transmission rate of roll vibration from the power unit to the base, and reduce vibration and noise at the base, which is particularly useful when applied to vehicles. It is something that can be done.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, and FIG. 1 is a schematic explanatory diagram showing the overall configuration;
FIG. 2 is an enlarged sectional view of the variable orifice, FIG. 3 is a sectional view taken along the line -- in FIG. 2, and FIG. 4 is an explanatory diagram showing the vibration frequency characteristics of roll rigidity. 5 to 8 show the second embodiment, FIG. 5 is an enlarged sectional view of the movable orifice, and FIG. 6 is a characteristic diagram for setting the optimum value of the movable range of the movable plate in the movable orifice. 7 and 8 are views corresponding to FIG. 5, respectively, showing a modification of the movable orifice.
FIG. 9 is a diagram corresponding to FIG. 1 showing the third embodiment. 1... Vehicle body,... Engine, 2a... Crankshaft, 4... Mount, 7... Fluid chamber, 9... Conduit, 10... Variable orifice, 12... Open hole,
13... Orifice hole, 14... Rotating body, 17...
... Controller, 24, 24', 24'' ... Movable orifice, 27 ... Orifice hole, 28 ... Movable plate, 29 ... Stopper section.

Claims (1)

[Claims] 1. Mounts arranged on both sides of the rotation axis of the power unit to elastically support the power unit with respect to the base, each mount having one mount in which an incompressible fluid is sealed. A fluid chamber is provided, and a conduit is provided for communicating the fluid chambers of both the mounts to allow movement of fluid and to correlate pressure changes in both fluid chambers, and a conduit disposed in the conduit to allow fluid movement within the conduit. 1. A mounting device for a power unit, comprising: a flow rate variable means for reducing the flow rate of fluid flowing in a conduit in a frequency range where roll rigidity increases due to a resonance phenomenon that sometimes occurs.