JPS6359884B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power unit support device that elastically supports a power unit with respect to a vehicle body.

Conventional power unit support devices include those shown in FIGS. 1 to 4. That is, in the figure, 1a is the engine, 1b is the clutch, 1
c is a transmission, which constitutes the power unit 1. 2 is a front mounting device, 3 is a front suspension member, 4 is a rear mounting device, and 5 is a rear mount member.

The details of the front and rear mounting devices 2, 4 are as shown in FIG. 3, consisting of an elastic body 6 made of elastic rubber, an upper plate 7, and a lower plate 8, and the elastic body 6 is formed into a solid prismatic shape. has been done. The upper surface plate 7 and the lower surface plate 8 are vulcanized and attached to both end surfaces of the elastic body 6 in the axial direction, and the upper and lower surface plates 7 and 8 have projecting portions on the side opposite to the elastic body 6 side. Each bolt 9 is attached. Then, the top plate 7 is fixed to the power unit 1 via the bolts 9,
Further, a lower plate 8 is fixed to the vehicle body, and in this way, the power unit 1 is supported on the vehicle body by the plurality of mounting devices 2 and 4. The load-deflection characteristics of the mounting devices 2 and 4 are as shown in the graph of FIG. 4, which shows a tendency for the spring constant to increase as the load increases.

However, in the case of such a conventional power unit support device, the elasticity of the elastic body 6 directly provides the spring characteristics of the mount device, and the elasticity of the elastic body 6 is always constant regardless of the high or low rotational speed of the engine 1a. It could only exhibit spring characteristics.

However, when the vehicle is idling or in a driving state where the accelerator operation is relatively gentle, small-amplitude vibrations (small vibrations) are generated from the power unit 1, and when the accelerator operation is sudden, the vehicle suddenly accelerates. In this case, the power unit 1 generates large vibrations in the roll direction due to changes in the torque of the engine 1a, resulting in large amplitude vibrations (large vibrations) in the longitudinal direction of the vehicle. Therefore, the mounting devices 2 and 4
The ideal spring characteristics are soft when idling or in driving conditions where the accelerator is relatively gentle, in order to suppress the muffled noise in the cabin due to small vibrations, and when the accelerator is operated suddenly. When rapidly accelerating by doing this, it is preferable to use a hard material in order to reduce large vibrations in the longitudinal direction of the vehicle.

Therefore, in order to cope with the above-mentioned small vibration, the elastic body 8
If the elastic body 8 is made soft to lower its elasticity, it will not be possible to reduce large vibrations during sudden acceleration, and if the elastic body 8 is made hard to increase its elasticity in order to cope with large vibrations during sudden acceleration, this will be the opposite of the case described above. It becomes impossible to suppress the muffled sound inside the vehicle. Therefore, the conventional mounting devices 2 and 4 are configured so that small vibrations with small amplitudes and large vibrations with large amplitudes can be absorbed in moderation.

As a result, in reducing both large and small vibrations, there was a problem in that only a halfway vibration reduction effect could be obtained both at high speeds and at low speeds.

SUMMARY OF THE INVENTION In order to solve these problems, it is an object of the present invention to provide a power unit support device that can suppress both large and small vibrations.

In order to achieve such an object, a power unit support device according to the present invention includes: a mount device that is interposed between a power unit and a vehicle body and supports the power unit on the vehicle body; an elastic body capable of changing a spring constant, a vehicle speed detection means for detecting vehicle speed, an engine load change speed detection means for detecting a speed of load change of the engine of the power unit, a detection result of the vehicle speed detection means and an engine load. a vehicle state prediction means for predicting that the vehicle is in a running state that causes large vibrations based on the detection result of the change speed detection means; and a vehicle state prediction means that predicts that the vehicle is in a running state that causes large vibrations. and a spring constant control means for increasing the spring constant of the elastic body when the elastic body is pressed.

The present invention will be explained below based on the drawings.

FIGS. 5 to 7 are diagrams showing an embodiment of the present invention.

First, to explain the structure, numeral 10 in FIG. 5 is a vehicle body side bracket, and this vehicle body side bracket 10
The box body has one of six sides open, and is fixed to a vehicle body side member such as the front suspension member 3 with the opening facing the power unit side. 1
Reference numeral 1 designates a power unit side bracket, which is formed from a long and thin plate, and has one longitudinal side facing into the opening of the vehicle body side bracket 10, and the other side facing the power unit side such as the engine bracket 1d. Fix it.

Further, reference numerals 12 and 13 in the figure are elastic bodies formed in a hollow disk shape of elastic rubber or the like, and the upper elastic body 12 is connected to the upper surface piece 10 of the vehicle body side bracket 10.
a and the power unit side bracket 11, and a lower elastic body 13 is interposed between the power unit side bracket 11 and the lower surface piece 10b of the vehicle body side bracket 10. The upper surface of the upper elastic body 12 is attached to the lower surface of the upper piece 10a, and the lower surface of the elastic body 12 is attached to the power unit side bracket 11.
The upper surface of the lower elastic body 13 is attached to the lower surface of the power unit side bracket 11.
The lower surfaces of 3 are vulcanized and adhered to the upper surface of the lower surface piece 10b, respectively. Furthermore, the upper surface piece 10a and the faceless piece 1
The two fluid chambers 14 and 15 formed in the upper and lower elastic bodies 12 and 13 are communicated with each other through communication passages 16 that penetrate through the upper and lower elastic bodies 12 and 13, respectively, and these fluid chambers 1
4 and 15 are filled with hydraulic fluid.

In the communication passage 16, an electromagnetic switching valve 17, which is a control means operated by a control signal, is provided. This electromagnetic switching valve 17 is a 2-port 2-position switching valve, and is normally connected to the communication path 16 by a spring 17a.
When a control signal is input, the solenoid 17b is energized and closes the communication path 16. The control signal for the electromagnetic switching valve 17 is outputted by a control circuit 20 using a microprocessor.

A signal related to the vehicle speed and a signal related to the engine condition are input to the control circuit 20. Based on these signals, the control circuit 20 predicts whether or not large vibration will occur in the power unit. When it is predicted that vibration will occur, a signal is output, and the electromagnetic switching valve 17 is operated to close the communication passage 16, thereby increasing the spring constant of the mount devices 2 and 4. As the vehicle speed detection means, the vehicle speed sensor 21 or an engine rotation speed detection sensor (not shown) can be used. These sensors output signals related to vehicle speed.

In addition, as an engine load change speed detection means,
An accelerator operation sensor 22 for measuring the accelerator depression speed, a throttle operation sensor (not shown) for measuring the opening/closing speed of the throttle valve, and a suction negative pressure sensor (not shown) for measuring the rate of change in the suction negative pressure. Pressure sensors can be used, and these sensors output signals related to the rate of change in engine load, and such engine 1a control signals indicate what load state the engine 1a is currently in. Detect. In addition,
23 and 24 shown in FIG. 6 are pulse counters.

In the control circuit 20, a vehicle speed signal as a signal related to the vehicle speed and an accelerator depression speed signal (referred to as a throttle speed in the following explanation) as a signal related to the engine condition are generated according to the graph shown in FIG. 8, for example. It is predicted that large vibrations will occur in the vehicle when the vehicle is within the region A indicated by the slope in the figure, and a drive current as a signal as a result of this determination is output to the electromagnetic switching valve 17. This drive current excites the solenoid 17b, switches its position, and closes the communication path 16.

Next, the reason why two signals, a signal related to vehicle speed and a signal related to engine load change rate, are used as spring constant control signals in the present invention will be explained.

Large vibrations occur when the power unit generates large vibrations in the roll direction due to changes in engine torque caused by sudden engine load changes, such as sudden throttle changes, when the vehicle is running, and this is transmitted to the vehicle body via the engine mount device. , which occurs as a result of the vehicle vibrating in the longitudinal direction.

Incidentally, changes in engine torque are proportional to engine load change speeds, such as throttle speed, and as the speed increases, torque changes become smaller. A signal related to the load change rate is used as a control signal for the spring constant.

As a specific example of a flowchart of the control circuit 20, a configuration as shown in FIG. 7 can be adopted. In the figure, V indicates the digital value of the vehicle speed signal (Km/h), and S indicates the digital value of the throttle speed (deg/sec). Note that steps for reading data, steps for reading flag data indicating whether the solenoid 17b is already "ON" or "OFF", etc. are omitted.

When the vehicle starts, it is first determined in step 1 whether the solenoid 17b of the electromagnetic switching valve 17 is in the "ON" state (energized state), and if the solenoid 17b is not "ON", the process proceeds to step 2. , here it is determined whether the vehicle speed is 3 km/h or more. In step 2, the vehicle speed is 3.
If it is determined that the vehicle speed is 18 km/h or more, the process proceeds to step 3, where it is further determined whether the vehicle speed is 18 km/h or more, and if the value is 18 km/h or more, the process proceeds to step 4, where the vehicle speed is determined by the following formula. Decide whether you are satisfied or not.

V≧16logS+6 When it is determined in step 4 that the vehicle speed does not satisfy the above equation, the process proceeds to step 5, where a drive current is output to turn on the solenoid 17b, and this drive current is used to turn the electromagnetic switching valve 17 on. It is activated to control closing of the communication path 16.

When the solenoid 17b is turned on in step 5, the time elapsed since the solenoid 17b was turned on is integrated in step 6, and the process proceeds to step 7, where it is determined whether one second has elapsed from the integrated value. In step 7, if it is determined that one second has elapsed from the integrated value, the process proceeds to step 8, where the drive current that has been output up to that point is cut off and the solenoid 17b is turned OFF. And step 9
Then, the timer value accumulated in step 6 is "cleared". In addition, step 7
If it is determined that the integrated value is less than 1 second, the solenoid 17b is kept "ON".

In step 1, when it is determined that the solenoid 17b is already in the "ON" state,
This process skips to step 6, and thereafter the process proceeds through the same order of steps as described above. In step 2, when it is determined that the vehicle speed is 3 km/h or less, there is no possibility that the large vibration will occur, and this process ends. Also, step 3
, when the vehicle speed is below 18km/h,
Look at what value the throttle speed is at,
If the digital value is 30deg/sec or more, skip to step 5, and if the digital value is 30deg/sec or more,
When it is 30 deg/sec or less, it can be determined that there is no risk of large vibrations occurring outside the area A shown in FIG. 8, so this process ends.

Furthermore, in step 4, the vehicle speed is expressed as V
When the value satisfies ≧16logS+6, there is no risk of large vibrations occurring, and this process ends.

After this process, the control circuit 20 sends out a drive current as an output signal.

Next, the effect will be explained.

When the vehicle speed is idling or in a driving state where the accelerator operation is relatively gentle, large vibrations do not occur, and the value determined by the vehicle speed and accelerator speed at this time falls within the area shown in Figure 8. A
Since the drive current is not output from the control circuit 20, the electromagnetic switching valve 17 remains open, and the two fluid chambers 14 and 15 are communicated with each other via the communication path 16. ing. here,
When a load is applied to the power unit side bracket 11, the hydraulic fluid moves between the two fluid chambers 14 and 15, so the vertical spring constant of the mounting devices 2 and 4 is maintained at a relatively small value. . Therefore, it is possible to reduce the roll vibration of the power unit during idling and the transmission of this roll vibration to the vehicle body, and it is also possible to suppress the noise inside the vehicle interior due to engine vibration during driving to a low level.

On the other hand, sudden accelerator operation (S≧
30deg/sec), the value determined by the vehicle speed, which is a signal related to the vehicle speed, and the accelerator speed, which is a signal related to the engine condition, shifts to within region A in Fig. 8, so this state The control circuit 20 predicts that large vibrations will occur in the power unit at a certain time, and sends a drive current as an output signal to the electromagnetic switching valve 17. As a result, before large vibrations occur in the power unit due to engine torque fluctuations, etc., the solenoid 17b is energized, the electromagnetic switching valve 17 is activated, the communication passage 16 is closed, and the two fluid chambers 14 and 15 are closed. Cut off communication.
As a result, the spring constant of the mount devices 2 and 4 increases and they become rigid, so that large vibrations of the power unit in the roll direction can be suppressed.
Therefore, the longitudinal vibration of the vehicle, which is a large vibration of the vehicle, caused by the vibration of the power unit can be significantly reduced.

In addition, in the embodiment described above, the electromagnetic switching valve 1
7 is shown, but it is not necessary to completely shut off the communication path 16, and when the solenoid 17b is excited, the communication path 1
6 may be restricted to substantially increase the spring constant of the mounting devices 2 and 4, and it is clear that the configuration of the electromagnetic switching valve 17 can be appropriately selected to accommodate this. The explanation is omitted.

As explained above, according to this invention,
It predicts that large vibrations will occur in the vehicle based on signals related to vehicle speed and engine load change rate, and automatically increases the spring constant of the mounting device, thereby quickly reducing large vibrations. can do. Therefore, when idling or in a driving state where the accelerator operation is relatively gentle, the spring constant of the mount device can be lowered to effectively absorb vibrations at this time, and it also prevents sudden accelerator operation while driving. If this is done, the spring constant of the mounting device can be increased to effectively absorb large vibrations of the power unit in the roll direction.
Therefore, it is possible to significantly reduce vehicle longitudinal vibration, which is a large vibration caused by the vibration of the power unit during sudden acceleration, etc., and it is also possible to suppress the transmission of vibrations that occur during idling or steady driving. It is possible to suppress muffled sounds in the vehicle interior.

Furthermore, since it is predicted whether or not the vehicle is in a state where large vibrations occur, it has the effect that large vibrations can be quickly reduced.

[Brief explanation of drawings]

Fig. 1 is a front view showing a conventional power unit support device, Fig. 2 is a side view of Fig. 1, Fig. 3 is a front view center vertical cross-sectional view of a conventional mount device, and Fig. 4 is Fig. 3 load-deflection characteristic diagram of the mounting device,
FIG. 5 is a partially cross-sectional explanatory diagram showing one embodiment of the present invention, FIG. 6 is a block diagram showing the main parts of FIG. 5,
FIG. 7 is a flowchart showing a specific example of a control circuit that is a component of the present invention, and FIG. 8 is a graph showing the relationship between vehicle speed and accelerator speed, showing the region where vehicle longitudinal vibration occurs. . 2, 4...Mount device, 10...Vehicle side bracket, 11...Power side bracket, 12,1
3...Elastic body, 14, 15...Fluid chamber, 16...
Communication path, 17... Solenoid switching valve (control means), 17
a...Spring, 17b...Solenoid, 20
... Control circuit, 21 ... Vehicle speed sensor, 22 ... Accelerator operation sensor.

Claims (1)

[Scope of Claims] 1. A mount device interposed between a power unit and a vehicle body to support the power unit on the vehicle body; an elastic body provided in the mount device and capable of changing a spring constant; and a vehicle speed detection device. a vehicle speed detecting means for detecting a change in load of the engine of the power unit; an engine load change speed detecting means for detecting a speed of change in load of the engine of the power unit; based on a detection result of the vehicle speed detecting means and a detection result of the engine load change speed detecting means; A vehicle state prediction means for predicting that the vehicle is in a running state that causes large vibrations, and a spring constant of the elastic body when the vehicle state prediction means predicts that the vehicle is in a running state that causes large vibrations. A power unit support device comprising: a spring constant control means for increasing the spring constant;