JPH0450202B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a device for controlling the spring characteristics and damping characteristics of a suspension bushing in a shock absorber for a vehicle. (Prior Art) The suspension bushing described above is designed to improve the damping characteristics and/or Spring characteristics can be changed. However, after the shock absorber is supported on the vehicle body side, the damping characteristics of the bush are uniquely determined, and in order to change these characteristics, the elastic body must be replaced. The characteristics of the suspension bushings mentioned above are usually set to suit the most frequently used driving conditions, and therefore, for example, when a passenger car is driven by only one driver, the spring constant of the suspension bushings is tend to be too large, resulting in poor riding comfort. (Object of the Invention) An object of the present invention is to provide a characteristic control device that can change the characteristics of a suspension bushing to characteristics suitable for when a vehicle is driven by only one driver. (Structure of the Invention) In order to achieve the above object, the present invention is structured as follows. That is, a hollow bag is provided inside the elastic body constituting the suspension bushing, and the characteristics of the elastic body are changed by supplying or discharging pressure fluid into the bag. There is. The fluid pressure circuit of the hollow bag is provided with a pressure control valve that can selectively switch between supplying and discharging pressure fluid to the bag, or closing the circuit. The control circuit for electrically controlling this pressure control valve maintains the pressure control valve in the supply state when the vehicle is stopped and the driver is the only passenger, and when the vehicle starts. After the pressure control valve is held in the discharge state for a certain period of time, it is configured to issue a signal to keep the fluid pressure circuit closed. (Example) Examples of the present invention will be described below with reference to the drawings. In FIGS. 1 and 2 showing suspension bushes (also called upper supports or strut mounts) of the shock absorber, a metal support member 14 is fixed to the vehicle body (not shown) by bolts 13. It is something that A metal connecting member 22 is connected to this support member 14 through an elastic body 23 such as rubber, and a ball bearing 28 that supports the upper end of a piston rod (not shown) of the shock absorber is fixed to this connecting member 22. has been done. The above-mentioned elastic body 23 is bonded to the support member 14 and the connection member 22 by hot-flow bonding, and as is clear from FIG. 25 is formed. Inside these hollow parts 25, there is a hollow bag body 36 formed of a stretchable material such as rubber.
is included. Further, each of these hollow bags 36 has a cap 38, and each cap 38 protrudes to the outside of the support member 14, and the hose 26 is connected thereto. Pressure fluid such as oil is supplied to or discharged from each of the bags 36 through these hoses 26.
By controlling the supply and discharge of the pressure fluid, the spring characteristics and damping characteristics of the elastic body 23 can be changed. Next, the fluid pressure circuit 50 that controls the supply and discharge of pressure fluid to each of the hollow inner pouch bodies 36 will be explained with reference to FIG. 3. This fluid pressure circuit 50 includes a pump 51 that pumps pressure fluid (for example, oil), a reservoir tank 52, and a first solenoid valve 53 and a second solenoid valve 5.
The pressure control valve A is provided with a pressure control valve A having a Both electromagnetic valves 53 and 54 constituting this pressure control valve A are arranged in series in the fluid pressure circuit 50.
When the first electromagnetic valve 53 is not energized, the pressure fluid forms a return path from the hollow bag body 36 to the reservoir tank 52 as shown in the figure, and when energized, the pressure fluid forms an outgoing path from the pump 51 to the hollow bag body 36. It functions to configure. Further, the second solenoid valve 54 functions to close the fluid pressure circuit 50 in the illustrated non-energized state, and to open this circuit 50 when energized.
Therefore, depending on the combination of energization and de-energization of both electromagnetic valves 53 and 54, the pressure inside the hollow bag body 36 changes as shown in the following table.

[Table] Next, control circuit B controls the energization and de-energization of current to both electromagnetic valves 53 and 54 of the pressure control valve A.
This will be explained with reference to FIG. First, this circuit B has four input terminals 56 to 59, of which three input terminals 56 to 58 are connected to the pressure sensor 6.
0 to 62 are connected, and the remaining input terminal 59 is connected to a vehicle speed sensor 63. Each pressure sensor 60 to 62 may be connected to a seat (not shown), for example.
This is a pressure-sensitive sensor that turns on when a passenger sits in the seat. However, the pressure sensor 60 is provided on the driver's seat, and the other pressure sensors 61, 6
2 is provided, for example, on the rear seat. It should be noted that these pressure sensors 60 to 62 are essentially used to detect the load of the vehicle, and therefore can be replaced with, for example, an internal pressure sensing sensor of a shock absorber. The continuous speed sensor 63 is normally turned on and off by a magnet provided on the output shaft of the vehicle at a frequency proportional to the rotation speed. The speed determination circuit 64 is an F/V converter for converting the pulse train signal from the vehicle speed sensor 63 into a voltage.
Converter 65 and setting device 66 for setting the reference voltage
and the voltage value from the F/V converter 65 is set by the setting device 66.
and a comparator 67 that outputs a high signal when the voltage exceeds the voltage value from . The signal from this comparator 67 will be expressed as SA hereinafter. Note that the reference voltage of the setting device 66 is set to a voltage equivalent to when the vehicle is stopped. The pressure determination circuits 68 to 70 are mainly composed of transistors TR ₁ to TR ₃ that output high and low signals depending on whether the pressure sensors 60 to 62 are turned on or off. Signals from each of these determination circuits 68 to 70 are hereinafter expressed as SB to SD. However, the signals SC and SD are input to an AND circuit 71, which will be described later, via inverters 72 and 73, respectively. The AND circuit 71 is for matching the above-mentioned signals SA to SD, and outputs a high signal when all of them are input as high signals. The signal from the AND circuit 71 will hereinafter be expressed as SE. The electromagnetic valve drive circuit 74 includes monostable multivibrators 75 and 76 (hereinafter abbreviated as "monostable"),
It is composed of an exclusive OR circuit 77 (hereinafter referred to as "EXOR") and amplifiers 78 and 79. The monostable 75 outputs a high signal for a certain period of time in response to the rise of the output signal SE from the AND circuit 71. This output signal is expressed as SF. The other monostable 76 outputs a high signal in response to the fall of the signal SE, and this output signal is represented by SG. In addition, the above EXOR77 has each monostable 75,
The exclusive OR of the respective signals SF and SG from 76 is calculated and outputted, and the output signal from this is expressed as SH. And the above amplifiers 78, 79
amplifies the above signals SF and SH, and the output signal is
The first solenoid valve 53 and the second solenoid valve 54 are driven by SF' and SH', respectively. In the above configuration, when the vehicle is stopped, the driver 1
Assuming that only the name of the passenger is on board, as is _clear from the time chart in _FIG . When it is determined that it is zero, a high signal SA ₁ is output. In addition, other pressure determination circuit 6
Signals from each transistor TR ₁ and TR ₃ of 9 and 70
For SC and SD, each pressure sensor 6
1 and 62 are off, a high signal is always output, so only the relationship between the speed determination circuit 64 and the pressure determination circuit 68 will be described here. Now, the signal SE of the AND circuit 71 is outputted as the high signal SE ₁ in FIG. 5 by the above-mentioned high signals SB ₁ and SA ₁ . This makes monostable 7
5 outputs a signal SF ₁ , which becomes an output signal SF ₁ ' through an amplifier 78 and energizes the first solenoid valve 53 . Also, due to the above signal SF ₁ , EXOR7
7 outputs a signal SH ₁ , which becomes the output signal SH ₁ ' of the amplifier 79 and energizes the second solenoid valve 54 .
By energizing both the electromagnetic valves 53 and 54, the internal pressure of the hollow bag body 36 increases, as is clear from the above table. The signal SF ₁ from the monostable 75 becomes a low signal after a certain period of time as shown in FIG. 5, and both the electromagnetic valves 53 and 54 become de-energized again. As a result, the internal pressure of the hollow bag body 36 is maintained at an increased level. Thereafter, when the vehicle starts, the signal _SE1 from the speed determination circuit 64 changes to a low signal.
As a result, the monostable 76 outputs a high signal SG ₁ , and the EXOR 77 outputs a high signal SH ₂ again. As a result, only the second solenoid valve 54 is energized by the signal SH ₂ ' outputted through the amplifier 79. By energizing the second solenoid valve 54 while the first solenoid valve 53 remains de-energized, the internal pressure of the hollow bag body 36 decreases, as is clear from the above table. Then, the high signal _SG1 of the monostable 76 becomes a low signal after a certain period of time, the second electromagnetic valve 54 is de-energized, and the internal pressure of the hollow bag body 36 is maintained at a low state. In this manner, when the vehicle is driven by only one driver, the internal pressure of the hollow bag body 36 is kept low, and the spring constant of the elastic body 23 of the suspension bushing is reduced to improve riding comfort. Although the case has been described in which there are four hollow bags 36 in this embodiment, this may be replaced with, for example, one communicating bag. It is also possible to use a computer as the control circuit B. (Effects of the Invention) As described above, the present invention can improve riding comfort by lowering the spring characteristics and damping characteristics of the suspension bush of the shock absorber when the vehicle is driven by only one driver.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of a suspension bushing in a shock absorber, FIG. 2 is a sectional view taken along the line -- in FIG. The figure is an electric circuit diagram mainly consisting of the control circuit, and FIG. 5 is a time chart showing the operating timing of the control circuit as it changes over time. 23...Elastic body, 36...Hollow bag body, 50...
Fluid pressure circuit, A... pressure control valve, B... control circuit.

Claims (1)

[Claims] 1. A suspension bush for a shock absorber that has a hollow bag inside the elastic body and is configured to change the characteristics of the elastic body by supplying or discharging pressure fluid to the inside of the bag, The fluid pressure circuit of the hollow bag is provided with a pressure control valve that can selectively switch between supplying and discharging pressure fluid to the bag, or closing the circuit, and a control for electrically controlling the pressure control valve is provided. The circuit maintains the pressure control valve in the supply state when the vehicle is stopped and only the driver is on board, and maintains the pressure control valve in the discharge state for a certain period of time when the vehicle starts. 1. A characteristic control device for a shock absorber suspension bushing, characterized in that it is configured to issue a signal for keeping a fluid pressure circuit closed.