JPH0479845B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) This invention relates to a pressure control device for a suspension bushing capable of injecting pressurized fluid, which is used at the connection between the upper end of a shock absorber attached to the front wheel side of a vehicle such as an automobile and the vehicle body. It is something. Prior Art As shown in FIGS. 1 and 2, a suspension bush 1 (hereinafter also referred to as "Atsupa Support") includes a link-shaped elastic member 2 and a supporting member fixed to the elastic member 2 in a manner surrounding the elastic member 2 from the outside. 3 and a connecting member 4 fixed to the inside of the elastic member 2. Inside the elastic member 2, four hollow parts 5 are arranged at equal intervals in the circumferential direction, and a hollow bag body 6 is housed in the hollow parts 5. The hollow bag body 6 has a cap 7,
It is connected to a hose 9 via a clamp 8,
This hose 9 communicates with a pressurized fluid source (not shown). A ball bearing 4a is attached to the connecting member 4, and the upper end of a piston rod 13 of the shock absorber is attached to this bearing 4a. When pressurized fluid is injected into the hollow bag 6 of this Atsupa support 1, the volume of the hollow bag 6 increases.
Therefore, the spring constant of the elastic member 2 increases and the height of the elastic member 2 increases, so the support member 3 rises and the vehicle height increases. Conversely, when the amount of pressurized fluid in the hollow bag body 6 is reduced, the spring constant of the upper support 1 becomes smaller and the vehicle height becomes lower. However, conventionally, the amount of pressurized fluid in the hollow bag 6 was adjusted while the vehicle was stopped, and it was impossible to adjust the amount while the vehicle was running. Purpose of the Invention This invention increases the height of the shock absorber on the front wheel side of the vehicle by increasing the height of the top support, thereby creating an anti-dive effect when braking the vehicle. The object of the present invention is to provide a pressure control device for the upper support of a shock absorber, which can improve the running stability of a vehicle by reducing changes in the posture of the shock absorber. Structure of the Invention In order to achieve the above object, the structure of the present invention is as follows. That is, the pressure control valve includes a pressure control valve having a first electromagnetic valve and a second electromagnetic valve, and a control circuit that includes a brake oil pressure sensor and controls the pressure control valve. The first solenoid valve has a first inlet in communication with the fluid reservoir, a second inlet in communication with the pump, and an outlet, and when energized puts the second inlet and the outlet in communication and when de-energized the first solenoid valve has a first inlet communicating with the fluid reservoir, a second inlet communicating with the pump, and an outlet. It has a function of communicating the first inlet and the outlet.
The second solenoid valve has an inlet that communicates with the outlet of the first solenoid valve and an outlet that communicates with the hollow bag of the upper support of the shock absorber, and when energized, the inlet and the outlet are communicated. , has the function of cutting off communication between the inlet and outlet by de-energizing. The control circuit includes a first monostable circuit that outputs a signal for a certain period of time to energize the first solenoid valve when the output signal of the brake oil sensor that detects that the brake oil pressure has exceeded a set value and outputs it is ON; A second monostable circuit that outputs an output signal for a certain period of time when the output signal of the brake oil pressure sensor is OFF, and the signal of this second monostable circuit and the signal of the first monostable circuit are inputted to energize the second solenoid valve. It has an exclusive OR circuit. Embodiments Next, the present invention will be described based on embodiments shown in the drawings. Note that the same components as in FIG. 1 are given the same reference numerals and their explanations are omitted. Third
The figure is a block diagram of one embodiment of this invention.
is Atsupa support, 10 is a pressure control valve, 14 is an oil pump, 15 is a fluid reservoir, 16 is a brake oil pressure switch (or brake oil pressure sensor), 2
0 is a control circuit. As shown in FIG. 4, the pressure control valve 10 consists of a first solenoid valve 11 and a second solenoid valve 12. The first solenoid valve 11 is a first solenoid valve that communicates with the oil pump 14.
a second inlet communicating with inlet P ₁ and fluid reservoir 15;
P ₂ and one outlet P ₃ . When the first solenoid valve 11 is energized, the second inlet P ₂ and the outlet P ₃ communicate with each other, and the communication between the first inlet P ₁ and the outlet P ₃ is cut off.
In addition, the first inlet _P1 and the outlet _P3 communicate with each other due to de-energization,
Communication between the second inlet P ₂ and the outlet P ₃ is cut off. On the other hand, the second solenoid valve 12 is connected to the outlet P ₃ of the first solenoid valve 11.
It has an inlet P ₄ that communicates with the hollow bag body 6 of the Atsupa support 1 and an outlet P ₅ that communicates with the hollow bag body 6 of the Atsupa support 1 via a hose 9. When the second solenoid valve 12 is energized, the inlet P ₄ and the outlet P ₅ communicate with each other, and when the second solenoid valve 12 is not energized, the inlet P 4 and the outlet P ₅ communicate with each other.
Communication with exit _P5 is cut off. Therefore, the first
The following truth table is obtained by combinations of energization and de-energization of the solenoid valve 11 and the second solenoid valve 12.

[Table] On the other hand, in the control circuit 20 shown in Fig. 5, 21 is a brake judgment circuit, and a brake oil pressure switch 16 (even if it is a brake oil pressure sensor) is turned on when the oil pressure in the brake system increases and reaches a set value. It is mainly formed of a transistor _TR1 that outputs a Hi or Lo signal depending on whether it is ON or OFF. Reference numeral 22 denotes a solenoid valve driving circuit, which is composed of monostable multivibrators 22a and 22b (hereinafter referred to as monostable), exclusive logic circuit 22c (hereinafter referred to as EXOR), and amplifiers 22d and 22e.
The first monostable 22a is for outputting a Hi signal for a predetermined time upon the rise of the signal SA, and the signal from now on will be SB shown in FIG. Similarly,
The second monostable 22b outputs a Hi signal for a certain period of time in response to the fall of the signal SA, and becomes the SC shown in FIG. EXOR22c is the signal SB, SC from the first and second monostables 22a, 22b, respectively.
The output signal is SD shown in FIG. 6. First,
The second amplifiers 22d and 22e are the first and second amplifiers, respectively.
It is for amplifying the signals SB and SD in order to drive the solenoid valves 11 and 12, and consists of a normal current amplifier. The output signals SB' and SD' from the first amplifier 22d and the second amplifier 22e have the same timing as the signals SB and SD shown in FIG. Next, the operation of this embodiment will be explained. While the vehicle is running, when the driver depresses a brake pedal (not shown) and the hydraulic pressure of the brake system reaches a set value, the brake hydraulic pressure switch 16 is turned on. As a result, the brake determination circuit 21 outputs a Hi signal _SA1 shown in FIG.
This signal SA ₁ is the brake oil pressure switch 1.
6 is ON, that is, from t ₁ to t ₃ . Next, when the Hi signal SA ₁ is output, the first monostable 22a is activated by the rising portion of the signal SA ₁ to output the Hi signal SB ₁ . This signal SB ₁ is amplified by the first amplifier 22d to become SB ₁ ', and the signal SB 1 is supplied to the first solenoid valve 11 from time t _1.
Energized until t ₂ . On the other hand, in response to the Hi signal SB ₁ output from the first monostable 22a, signals are output from the EXOR 22c and the second amplifier 22e, and the second electromagnetic valve 12 is energized from time _t1 to time _t2 . Therefore, according to the truth table, each hollow bag 6 of the upper support 1 communicates with the oil pump 14, so oil is injected and the pressure of the bag 6 increases. As a result, the elastic member 2 of the upper support 1 increases its spring constant and expands in volume, pushing the support member 3 up against the connecting member 4. Therefore, the vehicle body 19 side is pushed up with respect to the piston rod 13, and the vehicle height becomes higher. When the driver weakens the force on the brake pedal, the hydraulic pressure in the brake system decreases, and when the brake hydraulic switch 16 turns OFF, the signal SA ₁ of the brake judgment circuit 21 falls, so the second monostable 2
2b is activated and outputs a Hi signal _SC1 . This signal reaches the second solenoid valve 12 via the EXOR 22c and the second amplifier 22e, so the inlet _P4 and outlet _P5 of the second solenoid valve 12 communicate with each other. On the other hand, since the first solenoid valve 11 is not energized at this time, the first solenoid valve 1
1, the first inlet _P1 and the outlet _P3 are in communication. Therefore, each hollow bag 6 communicates with the fluid reservoir 15, the oil in the hollow bag 6 flows to the fluid reservoir 15, the oil pressure in the hollow bag 6 decreases, and the vehicle body 19 lowers. Then, the second monostable 22b is automatically turned off after operating for a predetermined period of time, and the operation of the second solenoid valve 12 is released, so that the oil in the hollow bag body 6 is in a sealed state, and the oil in the Atsupa support 1 is closed. The upper part of the piston rod 13 at the position returns to its normal height and maintains this state. That is, brake oil pressure switch 1
6 is not activated, the vehicle height remains at the normal height. Effects As is clear from the above explanation, according to the present invention, when the brake oil pressure switch is activated by applying the brakes while the vehicle is running, the pressure inside the hollow bag inside the Atsupa support increases. At the same time, the elastic member expands and the height of the vehicle increases, creating an anti-dive effect and ensuring safe running of the vehicle.

[Brief explanation of the drawing]

1 to 6 show an embodiment of the present invention,
Figure 1 is a longitudinal sectional view of the upper support part of an automobile shock absorber (cross-sectional view taken along the - line in Figure 2);
Fig. 2 is a sectional view taken along the - line in Fig. 1, Fig. 3 is a block diagram of the present invention, Fig. 4 is an explanatory diagram of the pressure control valve, Fig. 5 is a control circuit diagram, and Fig. 6 is the same as Fig. 5. FIG. 3 is a diagram showing a timing chart of each element constituting the control circuit. DESCRIPTION OF SYMBOLS 1... Suspension bush (Atsupa support), 6... Hollow bag body, 10... Pressure control valve, 11... First solenoid valve,
12...Second solenoid valve, 14...Oil pump, 15...
Fluid reservoir, 16... Brake oil pressure switch (brake oil pressure sensor), 20... Control circuit, 24... First monostable circuit, 26... Second monostable circuit, 27... Exclusive OR circuit.

Claims (1)

[Scope of Claims] 1. A pressure control device for a suspension bushing of a shock absorber on the front wheel side of a vehicle, which comprises: a suspension bushing of a shock absorber having an elastic member having a hollow bag; a first electromagnetic valve; and a second electromagnetic valve. a pressure control valve having a pressure control valve; and a control circuit including a brake oil pressure sensor and controlling the pressure control valve, the first solenoid valve communicating with a first inlet communicating with a fluid reservoir and a pump supplying pressurized fluid. the second inlet and one outlet, the second solenoid valve has a function of communicating the second inlet and the outlet when energized, and communicating the first inlet and the outlet when not energized; has an inlet that communicates with the outlet of the first solenoid valve and an outlet that communicates with the hollow bag of the suspension bushing, and when energized, the inlet and the outlet communicate with each other, and when not energized, the inlet and the outlet communicate with each other. The control circuit has a first solenoid valve that outputs electricity for a certain period of time when the output signal of the brake oil pressure sensor that outputs when the brake oil pressure is higher than a set value is ON, and energizes the first solenoid valve. a monostable circuit; a second monostable circuit that outputs an output signal for a certain period of time when the output signal of the brake oil pressure sensor is OFF;
A pressure control device for a suspension bush of a front wheel side shock absorber, comprising an exclusive OR circuit inputting a signal from the second monostable circuit and a signal from the first monostable circuit to energize the second solenoid valve.