JPH0568371B2 - - 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 the left and right sides of the power unit with the rotating shaft interposed therebetween. 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. 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. While low bounce stiffness is achieved by a moving spring constant when moving, there is a known system that increases roll stiffness by preventing fluid movement between the upper and lower chambers in response to roll vibration of the power unit. It is being

(Problem to be solved by the invention) However, since this conventional system is essentially intended to increase roll rigidity, the high roll rigidity causes a large transmission rate of the power unit's fluctuating torque to the base. Therefore, 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 within the conduit, the roll rigidity of the mounting device increases due to the change in frequency associated with the torque fluctuation of the power unit. It was found that the change occurs as shown by the alpha ray 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. The minimum value is reached at a few fa.

When the frequency increases beyond the above minimum frequency fa, 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 in the pipe, so the vibration increases relatively rapidly. Non-communicating spring constant (1+N)K(N
is equal to 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.

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 present invention was made through intensive research by the inventors in an attempt to solve this problem, and its purpose is, as described above, to communicate the fluid chambers of both mounts with each other through a conduit. In the mounting device, by partially setting the stiffness of a part of the wall of the fluid chamber in each mount to be low, and by controlling the deformation of the low-stiffness wall, the fluid flow in the high frequency range of the roll vibration mode is Changes in the volume of the chamber are absorbed by the low-rigidity walls, and at the same time, changes in volume in the low frequency range are absorbed by fluid movement between both mounts, ensuring that the spring characteristics of the power unit when rolling are always maintained regardless of the high or low frequency. The goal is to keep it soft.

(Means for Solving the Problems) In order to achieve the above object, the solving means of the present invention provides for
In order to elastically support the power unit on the base, a pair of mounts filled with incompressible fluid are provided, and the fluid chambers of both mounts are communicated to allow movement of the fluid. Provide a conduit for correlating pressure changes. Furthermore, a portion of the wall of each of the fluid chambers is formed of an elastic membrane that deforms in response to changes in fluid chamber pressure, and an elastic membrane deformation restraining means is provided to selectively prevent deformation of the elastic membrane. It is something.

(Function) With the above configuration, in the present invention, when the power unit rolls, the function of the elastic membrane deformation restraint means is stopped in the high frequency range where the fluid does not move in the conduit due to an increase in vibration frequency, and the elastic membrane is deformed. If this is allowed, changes in the volume of the fluid chamber of each mount will be absorbed by the deformation of its elastic membrane, and low roll rigidity can be maintained.

In addition, in the low frequency range, if the elastic membrane deformation restraining means is used to prevent the deformation of the elastic membrane, changes in the volume of the fluid chamber of each mount will be absorbed by the fluid moving through the conduit. Therefore, it is possible to keep the roll rigidity 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.

(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 engine on a vehicle body, where 1 is the vehicle body as a base, and 2 is mounted and supported at the bottom of the engine room of the vehicle body 1. This is an engine serving as a power unit, and brackets 3, 3 extending substantially horizontally are integrally provided on both left and right side surfaces of the engine 2, sandwiching a rotating shaft, that is, a crankshaft 2a, and are connected to the vehicle body. 1, that is, on both sides of the crankshaft 2a of the engine 2, a pair of mounts 4, 4 for elastically supporting the engine 2 with respect to the vehicle body 1 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 a movable plate 7a and a thin rubber 7b bonded to the outer periphery of the movable plate 7a. 5, elastic wall 6 and elastic membrane 7
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 the conduit 10 is connected to the cases 5, 5 of the two mounts 4, 4, respectively,
This conduit 10 is configured to communicate the fluid chambers 8, 8 of both the mounts 4, 4 with each other to allow movement of fluid, and to correlate pressure changes in both the fluid chambers 8, 8.

Further, reference numeral 11 denotes a stopper plate that restricts upward deformation of each elastic membrane 7 by more than a predetermined amount. Communication holes 12, 12, . . . are opened to allow movement.

On the other hand, a substantially cup-shaped support plate 14 whose outer edge is fixed to the lower end of the case 5 of the mount 4 is disposed below the elastic membrane 7. A support hole 17 is opened in the support plate 14, and a push rod 16 having an abutment portion 16a at an upper end capable of abutting against the movable plate 7a of the elastic membrane 7 is provided in the support hole 17.
is fitted and supported so as to be movable in the vertical direction, and when the push rod 16 is at the lower end position, the distance between the contact portion 16a and the elastic membrane 7 is equal to the distance between the stopper plate 11 and the elastic membrane 7. It is set to be equivalent to

Further, an electromagnet 18 is attached to the support plate 14, and the electromagnet 18 attracts the push rod 16 and moves it upward when energized.
When the push rod 16 is de-energized, the push rod 16 moves downward to allow deformation of the elastic membrane 7, while the electromagnet 18 is energized to move the push rod 16 upward and its contact portion 16a pushes the elastic membrane 7 against the stopper plate. An elastic membrane deformation prevention means 19 is configured to prevent the deformation of the elastic membrane 7 by pressing against the elastic membrane 11, and thereby selectively prevent the deformation of the elastic membrane 7.

Furthermore, although not shown, a controller is connected to each of the electromagnets 18, and the outputs of various sensor groups for detecting the operating state of the engine 2 are input to the controller. Accordingly, energization to each electromagnet 18 is controlled.

Next, the operation of the above embodiment will be explained.
When the frequency of roll vibration of the engine 2 is higher than the frequency ₀ corresponding to the static spring constant K when both mounts 4 and 4 are connected as shown in Fig. 2, each electromagnet is controlled by the controller. 18
is maintained in a non-energized state, and the push rod 16 of the engine 2 is held at the lower end position slightly away from the elastic membrane 7, so that the elastic membrane 7 is in a state where it 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, , even though the fluid chambers 8, 8 of both mounts 4, 4 are communicated by a conduit, the roll spring constant of the mounting device is K + ΔK, which is the static spring constant K plus the membrane rigidity ΔK of the elastic membrane 7. Therefore, it remains low regardless of changes in vibration frequency.

On the other hand, in a low frequency range where the roll frequency is below the frequency ₀ , the controller energizes the electromagnet 18 and moves the push rod 16 upward.
As the push rod 16 rises, the elastic membrane 7 is pressed against the stopper plate 11 and its deformation is prevented. Therefore, the fluid in both fluid chambers 8, 8 moves through the conduit 10 with the roll vibration of the engine 2, and the change in volume of the fluid chamber 8 is absorbed by the fluid movement, and the α line in FIG. It is possible to keep the roll stiffness extremely low by effectively utilizing the maximum effect range in the frequency characteristics of the mount stiffness in the roll mode shown in FIG. 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. .

Furthermore, when each electromagnet 18 is in a non-energized state, a large static torque is applied to the mounting device due to the torque reaction force of the engine 2, and the volume of each fluid chamber 8 changes, as when the vehicle accelerates in a low gear. , the fluid in both fluid chambers 8, 8 moves through the conduit 10, and due to the fluid movement, the change in volume of the fluid chamber 8 is absorbed, and the elastic membrane 7 is kept in the same state as when no load is applied. . Therefore, when the fluid chambers 8, 8 of both mounts 4, 4 are not connected through the conduit 10, when the same static torque is applied, the elastic membrane 7
While the roll rigidity increases when the roller contacts the stopper plate 11, the roll rigidity can be kept low due to the neutral state of the elastic membrane 7, thereby reducing the vehicle body vibration, noise, etc. even during static torque displacement. be able to.

Furthermore, when the torque fluctuates greatly during sudden acceleration/deceleration or gear changes of the vehicle, each elastic membrane 7 deforms due to the temporal movement delay of the fluid in the conduit 10 during the transient period until the torque reaches a steady state. do,
Contact portion 1 of the push rod 16 at the lowering end position
6a, the fluid flows through the conduit 10 and moves between the two fluid chambers 8, 8, increasing the roll rigidity, damping and regulating excessive movement of the engine 2, and reducing vibrations and shocks. It can be relaxed.
In this case, if an orifice (not shown) is disposed in the middle of the conduit 10, when the torque fluctuates greatly during rapid acceleration/deceleration of the vehicle or when changing gears, the torque becomes a steady state.
After each elastic membrane 7 deforms and comes into contact with the contact portion 16a of the push rod 16, the fluid flows through the conduit 10 with a sufficient time delay. Since the engine 2 moves between the two fluid chambers 8, 8, the roll rigidity can be increased, and excessive movement of the engine 2 can be attenuated and regulated to alleviate vibrations and shocks.

In addition, at the time of bounce vibration due to unbalance in the engine 2, vehicle running vibration, etc., the volume change of the fluid chamber 8 in each mount 4 is caused by the deformation of each elastic membrane 7, as in the case of the roll vibration mode. Absorbed. Therefore, it is possible to keep the bounce rigidity of the mounting device low and reduce the transmission rate of engine bounce vibration to the vehicle body 1.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention, in which
In the configuration of the embodiment, an electromagnetic on-off valve 20 is provided at an intermediate position of a conduit 10 that communicates both mounts 4,4. The electromagnetic on-off valve 20 includes a valve case 21 that is connected to the conduit 10 and has a valve seat 21a inside, a valve body 22 that is fitted into the valve case 21 and can be seated on the valve seat 21a, and the valve body 22
It includes a spring (not shown) that biases the valve to open, and an electromagnet 23 that attracts the valve body 22 in the valve closing direction against the biasing force of the spring. In the above, a type was described in which a spring (not shown) biases the valve body 22 to open. It may also be of a type that includes an electromagnet 23 that attracts in the direction of the valve. The positional relationship of the valve body 22 with respect to the valve seat 21a is such that when the engine 2 rolls in the clockwise direction due to the torque reaction force when the vehicle moves forward, the valve body 22 in the closed state is connected to both the mounts 4, 4. The valve seat 21a is set to be urged into close contact with the valve seat 21a due to the difference in fluid pressure between the valve seats 21a and 21a. The rest of the structure is the same as that of the first embodiment.

Therefore, in this embodiment, the electromagnetic on-off valve 20
When the electromagnetic on-off valve 20 is opened, the same effect as in the first embodiment can be achieved.On the other hand, when the electromagnetic on-off valve 20 is closed, there is no movement of fluid through the conduit 10 between the mounts 4, 4. Therefore, when a large static torque is applied, when the electromagnet 18 is not energized, it comes into contact with the stopper plate 11 or the contact portion 16a of the push rod 16 at the lower end position, and when the electromagnet 18 is energized, it is Since the elastic membrane 7 forms a fixed wall due to the restraint by the push rod 16, the roll rigidity is increased. Therefore, there is an advantage that the above two types of spring characteristics can be selected by switching the electromagnetic on-off valve 20 to open and close depending on the operating condition of the vehicle, and desired characteristics can be obtained.

Further, the electromagnetic on-off valve 20 is set so that the closing force of the valve body 22 increases due to the torque reaction force generated when the vehicle moves forward, which occurs frequently, so the current supplied to the electromagnet 23 when the valve is closed is small. In addition, there is an advantage that the electromagnet 23 can be made small and have low attraction ability.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention, in which the fluid chamber 8 of each mount 4 is separated into a main chamber 24 and a sub-chamber 25 having an elastic membrane 7 as a wall. , 25 to restrict deformation of the elastic membrane 7.

That is, in this embodiment, the fluid chamber 8 of each mount 4 has an elastic wall 6 connected to the engine 2, and an upper main chamber 24 connected to the conduit 10.
, a lower auxiliary chamber 25 having the elastic membrane 7 as a wall, and a communication passage 26 that communicates both chambers 24 and 25. An electromagnetic on-off valve 27 for selectively opening and closing the communication passage 26 is disposed at an intermediate position of the communication passage 26, and this on-off valve 27 selectively prevents deformation of the elastic membrane 7 of the auxiliary chamber 25. is configured to do so.

In addition, 28 is a stopper plate that restricts downward deformation of the elastic membrane 7 disposed in the auxiliary chamber 25 by a predetermined amount or more, and between the stopper plate 28 and the elastic membrane 7 there is communication with the outside air. An air chamber 29 is formed. Further, the control system for the on-off valve 27 is constructed in the same manner as in the first embodiment.

Therefore, in the case of this embodiment, the on-off valve 27 is opened when the roll vibration of the engine 2 is in a high frequency range of frequency ₀ or more as shown in FIG. In this state, the main chamber 24 and the auxiliary chamber 25 of each fluid chamber 8 communicate with each other, so that each elastic membrane 7 deforms due to the roll vibration of the engine 2 and absorbs the volume change of the fluid chamber 8. Therefore, the roll spring constant of the mounting device is K+ΔK, which is the static spring constant K plus the membrane rigidity ΔK of the elastic membrane 7, and is kept low. On the other hand, the on-off valve 27 is closed in a low frequency range where the vibration frequency is ₀ or less. In this state, pressure changes are not transmitted to the elastic membrane 7, and the fluid in both main chambers 24, 24 moves through the conduit 10, and the volume change in the fluid chamber 8 is absorbed by the fluid movement, so that the roll mode is activated. Roll stiffness can be kept low by effectively utilizing the maximum effect range of the frequency characteristics of mount stiffness. Therefore, in this embodiment as well, the same effects as in the first embodiment can be achieved.

Furthermore, if the air chamber 29 is provided with an orifice for communication with the outside air and an orifice with a movable plate, not only can the same effects as in the above embodiments be obtained, but also the orifice can prevent bounce vibrations of the engine 2. A damping effect can be obtained.

(Fourth Embodiment) FIG. 5 shows a fourth embodiment of the present invention.
In the configuration of the embodiment, the elastic membrane 7 is directly attracted by electromagnetic force to prevent its deformation.

That is, in this embodiment, a ferromagnetic material 30 such as iron is integrally attached to the center of the elastic membrane 7. Further, an electromagnet 32 that attracts the ferromagnetic material 30 of the elastic film 7 is provided at the center of the support plate 31 on the lower side of the elastic film 7. When the electromagnet 32 is energized, the ferromagnetic material 30 is attracted to the electromagnet 32. 30 to prevent its deformation. The rest of the structure is the same as that of the first embodiment.

Therefore, in the case of this embodiment, in the high frequency range of the roll vibration frequency of the engine 2, deformation of the elastic membrane 7 is allowed by cutting off the current to the electromagnet 32, so that the roll spring constant of the mounting device is low. It is maintained. On the other hand, in the low frequency range of the roll vibration, the ferromagnetic material 30 of the elastic membrane 7 is
is attracted to the electromagnet 32 and its movement is restricted, so the roll rigidity is kept low due to fluid movement between the two fluid chambers 8, 8, and therefore the roll rigidity of the mounting device is always maintained regardless of the high or low frequency. Can be kept low.

(Effects of the Invention) As described above, according to the present invention, fluid-filled mounts are arranged on both sides of the rotation axis 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 By forming a part of the elastic membrane with an elastic membrane and selectively preventing the deformation of the elastic membrane, the deformation of the elastic membrane prevents the change in volume of each fluid chamber in the high frequency range during roll vibration of the power unit. At the same time, the volume change in the low frequency range can be absorbed by the fluid movement between the two fluid chambers to maintain low roll rigidity, thereby improving the spring characteristics of the power unit when it rolls. Regardless of the high or low frequency, it is always kept soft and reduces the transmission rate of roll vibration to the base, which can alleviate the vibration and noise of the base.In particular, when applied to vehicles, the vibration and noise level of the vehicle body can be reduced. can be effectively reduced.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic explanatory diagram showing the overall configuration of the first embodiment, and FIG. 2 is an explanatory diagram showing the vibration frequency characteristics of the roll rigidity. FIG. 3, FIG. 4, and FIG. 5 are views corresponding to FIG. 1 showing a second embodiment, a third embodiment, and a fourth embodiment of the present invention, respectively. DESCRIPTION OF SYMBOLS 1... Vehicle body, 2... Engine, 2a... Crankshaft, 4... Mount, 6... Elastic wall, 7... Elastic membrane, 8... Fluid chamber, 11... Stopper plate, 16... Push rod , 16a... Contact portion, 18, 23, 32... Electromagnet, 19... Elastic membrane deformation prevention means, 20, 27... Electromagnetic shut-off valve, 2
4...Main chamber, 25...Sub-chamber, 30...Ferromagnetic material.

Claims (1)

[Claims] 1 Equipped with mounts arranged on both sides of the power unit across the rotational axis to elastically support the power unit with respect to the base, and each mount is filled with incompressible fluid, while the fluid in both mounts is A conduit that communicates the chambers to allow movement of fluid and correlates pressure changes in both fluid chambers, and an elastic membrane that forms part of the wall of each of the fluid chambers and deforms in response to changes in fluid chamber pressure. 1. A power unit mounting device comprising: and elastic membrane deformation restraining means for selectively preventing deformation of the elastic membrane.