JPH0637132B2 - 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 pair of mounts that elastically support the power unit with respect to the base are provided, and an upper chamber of the left mount and a lower chamber of the right mount, and a lower chamber and a right mount of the left mount. The upper chambers are connected by independent conduits, and for the bounce vibration of the power unit, low bounce rigidity is obtained by the moving spring constant when the fluid moves between the upper and lower chambers communicating with each other on both mounts. With respect to roll vibration of the power unit, it is known that the roll rigidity is increased by not moving the fluid between the upper and lower chambers.

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

On the other hand, as a conventional example other than the above, for example, US Pat.
As disclosed in Japanese Patent No. 705118, each of the mounts arranged on both sides of the rotating shaft 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 the fluid chambers of both mounts are connected by a conduit having an orifice so that transient large torque fluctuations of the power unit are damped by the orifice.

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

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

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

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

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

On the other hand, when the roll rigidity in the low frequency range is low,
When a large transient torque is generated, there is a risk that the power unit will excessively move with a large amplitude and interfere with other members.To prevent this, increase the spring constant according to the operating conditions of the power unit. Is desired.

The present invention has been made in view of the above points, and an object of the present invention is, as described above, in a mounting apparatus in which fluid chambers of both mounts on the side of a power unit communicate with each other by a conduit. By controlling the movement, the spring constant is reduced in the reverse effect region of the roll frequency and the excessive movement of the power unit is prevented when a transient large torque is generated.

(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, the operating state detecting means for detecting the operating state of the power unit, and the communication between the two fluid chambers arranged in the path of the conduit are opened and closed according to the operating state of the power unit detected by the operating state detecting means. An on-off valve is provided.

(Operation) With the above configuration, in the present invention, the operating state of the power unit is detected by the operating state detecting means, and the open / close valve is opened / closed according to the operating state of the power unit. That is, when the roll frequency of the power unit is lower than the frequency corresponding to the non-communication spring constant during non-communication with the fluid chamber, when the on-off valve is opened, the fluid moves in the conduit due to the roll vibration, The spring constant is kept low.

On the other hand, when the roll frequency is equal to or higher than the frequency corresponding to the non-communication spring constant, when the on-off valve is closed, communication between the fluid chambers of both mounts is cut off, and fluid movement in the conduit is blocked. Therefore, the spring constant is maintained at the above-mentioned non-communication spring constant, so that the spring constant is reduced in the inverse effect region near the natural frequency fn.

Further, if the on-off valve is closed when the torque generated by the power unit detected by the operating state detection means is equal to or greater than the set value, the fluid constant in the conduit prevents the spring constant from being greater than the static spring constant when communicating with the fluid chamber. Is switched to a large non-communication spring constant, and excessive movement of the power unit due to an increase in roll rigidity is prevented.

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

FIG. 1 shows an overall configuration of a first embodiment applied when mounting a vehicle reciprocating engine on a vehicle body.
Is a vehicle body as a base, 2 is an engine as a power unit mounted and supported on the bottom of the engine room of the vehicle body 1, and the rotation shaft of the engine 2, that is, the left and right side surfaces sandwiching the crankshaft 2a are substantially Horizontally extending brackets 3, 3 are integrally provided so as to project, and the brackets 3, 3 and the vehicle body 1
, That is, on both sides of the crankshaft 2a of the engine 2, sandwiching mounts 4 and 4 for elastically supporting the engine 2 with respect to the vehicle body 1.

Each of the mounts 4 is fixed to the vehicle body 1 and has a cylindrical bottomed case 5 having an open upper surface, and an upper opening opening of the case 5 is hermetically sealed, and is connected to each bracket 3 via a connecting bolt 8. An elastic wall 6 made of rubber or the like is provided, and a sealed fluid chamber 7 in which an incompressible fluid (liquid) is enclosed is formed in the case 5 by the elastic wall 6.

Also, the ends of the conduit 9 are connected to the cases 5 and 5 of the mounts 4 and 4, respectively, and the conduit 9 allows
The fluid chambers 7, 7 of the mounts 4, 4 are communicated with each other to allow movement of the fluid, and pressure changes in the fluid chambers 7, 7 are associated with each other.

An electromagnetic opening / closing valve 10 for switching between opening and closing the fluid communication between the fluid chambers 7 of the mounts 4 and 4 is provided at an intermediate position in the path of the conduit 9 that communicates the mounts 4 and 4. ing. The electromagnetic on-off valve 10 is connected to the conduit 9 and has a valve case 11 having a valve seat 11a therein, a valve body 12 fitted in the valve case 11 and seatable on the valve seat 11a, and the valve body 11. A spring (not shown) for urging the valve 12 to open is provided with an electromagnet 13 for attracting the valve body 12 in the valve closing direction against the urging force of the spring.
It is open when power is off but closed when power is on.
Further, although the above description has been made on the type in which the valve body 12 is biased to open by a spring (not shown), the spring for biasing the valve body 12 to close and the valve opening direction against the biasing force of the spring. The electromagnet 13 that is attracted to the electromagnet 13 is closed and is closed when the electromagnet 13 is not energized, but may be of a type that opens when energized. The positional relationship of the valve body 12 with respect to the valve seat 11a is such that the valve body 12 in the valve closed state is mounted on both mounts 4 and 4 when the engine 2 is rolled in the clockwise direction in the figure due to the torque reaction force when the vehicle is moving forward. It is set so as to be urged closely to the valve seat 11a due to the difference in fluid pressure.

Further, the electromagnet 13 of the on-off valve 10 has the electromagnet 13
A controller 14 for controlling energization to the engine is connected to the controller 14. A rotation sensor 15 for detecting the number of revolutions of the engine 2 and an accelerator opening sensor 16 for detecting an accelerator opening (intake negative pressure) of the vehicle are connected to the controller 14. A shift position sensor 17 for detecting the shift position of the transmission of the vehicle, a vehicle speed sensor 18 for detecting the traveling speed of the vehicle, and the engine 2
A vibration sensor 19 for detecting a vibration such as a roughness state of
Each output from the clutch sensor 20 for detecting the ON / OFF state of the clutch of the vehicle is input. Each of these sensors 15 to 20 constitutes an operating condition detecting means for detecting the operating condition of the engine 2.
The controller 14 determines the operating state of the vehicle based on the detection signals of 5 to 20, and automatically controls the opening / closing valve 10 accordingly.

Therefore, in the above embodiment, each sensor 15-2
When the controller 14 receives the detection signal of 0, the lowest order component of the torque fluctuation of the engine 2 (for example, 4 cycles 4
In the cylinder engine, the roll frequency of the secondary component) is detected, and as shown by the solid line in FIG. 2, when the frequency makes both fluid chambers 7, 7 non-communication state, the non-communication spring constant (1+
N) On-off valve 1 when frequency f corresponding to K is lower than
0 is opened, and the on-off valve 10 is closed when the frequency is equal to or higher than fe. As a result, the roll spring constant becomes lower in the low frequency range lower than the frequency fe, and the communication effect is obtained as it is, while in the frequency range higher than the frequency fe, the reverse of the natural frequency fn near The spring constant no longer increases in the effect area, and the spring constant is the non-communication spring constant (1 + N) K
Kept in. Therefore, it is possible to reduce the roll rigidity as a whole, reduce the transmission rate of the roll vibration of the engine 2 to the vehicle body 1, and reduce the vibration and noise in the vehicle body 1.

Further, the engine speed detected by the sensors 15 to 20, the accelerator opening (intake negative pressure), the shift position of the transmission,
The generated torque of the engine 2 is detected based on the vehicle speed, the vibration state of the engine 2 such as roughness, and the ON / OFF state of the clutch. When the generated torque is equal to or more than a set value, the on-off valve 1
0 is closed. By the closing operation of the opening / closing valve 10, the roll spring constant increases from the communicating static spring constant K at the time of communication to the non-communicating spring constant (1 + N) K as shown in FIG. 3 to increase the roll rigidity. Excessive movement of the engine 2 when a large transient torque is generated can be restricted to reduce interference with other members, transient vibration, and shock.

Further, the on-off valve 10 is set so that the closing force of the valve body 12 is increased by the torque reaction force at the time of vehicle forward, which frequently occurs, so that the supply current to the electromagnet 13 at the time of valve closing can be small. The electromagnet 13 can be made small with a low suction ability.

The on-off valve 10 in the above-described embodiment can be opened and closed by manual operation by a vehicle occupant.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention. In the first embodiment, the opening / closing valve 10 is provided on the vehicle body 1 side, while the engine 2
It is provided on the side.

That is, in this embodiment, the oil passage 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. An on-off valve 19 arranged at an intermediate position of the conduit 9 is attached to the engine 2 side. Others are the same as in the first embodiment. Therefore, also in this embodiment, it is possible to obtain the same effects as those of the first embodiment.

(Effects of the Invention) As described above, according to the present invention, the fluid sealing mounts for elastically supporting the power unit on the base are arranged on both sides of the rotating shaft of the power unit, and the fluid chambers of the both mounts are formed by the conduits. A roll spring that communicates with the conduit and that is provided with an on-off valve that opens and closes according to the operating state of the power unit, increases the roll vibration of the power unit in the inverse effect region near the natural frequency of the fluid in the conduit. The constant can be suppressed by closing the on-off valve to keep the roll rigidity low, and the transfer rate of roll vibration from the power unit to the base can be reduced to reduce vibration and noise on the base. You can When a large transient torque is generated, the roll spring constant is increased by closing the opening / closing valve to restrict excessive movement of the power unit, prevent interference with other members of the power unit, and reduce transient vibration and shock. It is possible to exert a useful effect especially when applied to a vehicle.

[Brief description of drawings]

1 to 3 show a first embodiment of the present invention. FIG. 1 is a schematic explanatory view showing the entire structure, FIG. 2 is an explanatory view showing vibration frequency characteristics of roll rigidity, and FIG. FIG. 6 is an explanatory diagram showing characteristics of roll rigidity change when the on-off valve is opened and closed. FIG. 4 is a view corresponding to FIG. 1 showing the second embodiment. 1 ... Body, 2 ... Engine, 2a ... Crankshaft, 4
...... Mount, 7 ...... fluid chamber, 9 ...... conduit, 10 ...... open / close valve, 14 ...... controller.

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. A conduit for communicating the fluid chambers of the fluid chambers with each other to allow movement of the fluid and associating a pressure change between the fluid chambers, an operating state detecting means for detecting an operating state of the power unit, and a conduit arranged in the conduit. A mounting device for a power unit, comprising: an opening / closing valve that opens and closes the communication between the two fluid chambers in accordance with the operating state of the power unit detected by the operating state detecting means.