JPH0437763Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an electronically controlled suspension device that can reduce roll that occurs in a vehicle body during cornering.

[Technical background of the invention and its problems] For example, as shown in U.S. Pat. No. 3,124,368, fluid in a fluid cylinder provided between the vehicle body and the wheels is controlled based on the acceleration acting on the vehicle body. Accordingly, there are known devices configured to reduce changes in the posture of the vehicle body caused by the acceleration.
However, in the device shown in this US patent, since the fluid in the fluid cylinder is controlled by a complicated mechanism, the device is expensive and its adjustment is troublesome.

[Purpose of the invention] The present invention was made in view of the above points, and its purpose is to use a valve with a simple mechanism without using a complicated servo mechanism as in conventional devices, and to reduce acceleration. An object of the present invention is to provide an electronically controlled suspension device that can perform attitude control with an appropriate control amount based on the output of a sensor and in accordance with the actual lateral acceleration acting on the vehicle body.

[Summary of the invention] A fluid spring chamber interposed between the wheels and the vehicle body,
a fluid supply device that supplies fluid to the fluid spring chamber via a supply valve; a fluid discharge device that discharges fluid from the fluid spring chamber via a discharge valve; and a signal responsive to horizontal acceleration acting on the vehicle body. and a control time determining means for determining a valve control time according to the output of the acceleration sensor, and during the control time determined by the control time determining means, the fluid spring chamber on the outside of the rotation This electronically controlled suspension device is characterized by comprising a controller that outputs a control signal to open a supply valve of the fluid spring chamber and a discharge valve of the fluid spring chamber on the inner side of the rotation.

[Embodiment of the invention] An electronically controlled suspension device according to an embodiment of the invention will be described below with reference to the drawings.
In Figure 1, the air suspension unit
Since FS1, FS2, RS1, and RS2 each have almost the same structure, the air suspension unit will be explained below using the symbol S, unless the front and rear units are specifically explained. do.

That is, the air suspension unit S incorporates a strut-type shock absorber 1, and this shock absorber 1 is fitted into a cylinder attached to the front wheel or rear wheel side, and is slidably inserted into the cylinder. The cylinder is equipped with a piston, and the cylinder moves up and down relative to the piston rod 2 in response to the up and down movement of the wheels, thereby making it possible to effectively absorb shock.

Incidentally, an air spring chamber 3 which also serves as a vehicle height adjustment fluid chamber is disposed coaxially with the piston rod 2 in the upper part of the shock absorber 1, and a bellows 4 is formed in a part of this air spring chamber. Therefore, the passage 2a provided in the piston rod 2
By supplying and discharging air to and from the air spring chamber 3 through the piston rod, the piston rod can be moved up and down.

Further, the outer wall of the shock absorber 1 is provided with a spring receiver 5a facing upward, and the outer wall of the air spring chamber 3 is provided with a spring receiver 5b facing downward.
are formed, and a coil spring 6 is loaded between these spring receivers 5a and 5b.

Thus, 11 is a compressor. This compressor 11 compresses the atmospheric air sent from the air cleaner 12 and supplies it to the dryer 13 . The compressed air dried with silica gel or the like from the dryer 13 is transferred to the reserve tank 15 via the check valve 14 . It is stored in the high pressure side reserve tank 15a. This reserve tank 1
5 is provided with a low pressure side reserve tank 15b. A compressor 16 driven by a compressor relay 17 is provided between the reserve tanks 15a and 15b. Further, a pressure switch 18 is provided which is turned on when the pressure in the low pressure side reserve tank 15b becomes equal to or higher than atmospheric pressure.
When the pressure switch 18 is turned on, the compressor relay 17 is driven. As a result, the reserve tank 15b is always kept below atmospheric pressure. The route by which compressed air is supplied from the high-pressure side reserve tank 15a to the suspension unit S is indicated by a solid arrow. That is, the compressed air from the reserve tank 15a is passed through the air supply solenoid valve 19, the air supply flow rate control valve 20 consisting of a three-way valve, the check valve 21, the front right solenoid valve 22, and the front left solenoid valve 23. It is sent to the front right suspension unit FS2 and the front left suspension unit FS1. Similarly, the compressed air from the reserve tank 15a is supplied to an air supply solenoid valve 19, an air supply flow rate control valve 20 consisting of a three-way valve, and a check valve 2.
4. It is sent to the rear right suspension unit RS2 and the rear left suspension unit RS1 via the rear right solenoid valve 25 and the rear left solenoid valve 26. In addition, high pressure reserve tank 15a, air supply solenoid valve 1
9, air supply flow control valve 20, front right solenoid valve 22, front left solenoid valve 23, rear right solenoid valve 25,
The rear left solenoid valve 26 constitutes a fluid supply device. solenoid valve 22,
23, 25, and 26 each consist of a three-way valve, and when each solenoid valve is in the OFF state, fluid can be supplied to the fluid spring chamber 3, and the fluid spring chambers 3 of the left and right suspension units are communicated. Further, when each solenoid valve is in the ON state, fluid can be discharged from the fluid spring chamber 3, and the fluid spring chambers 3 of the left and right suspension units are disconnected from each other. In this way, the supply and discharge of fluid to each fluid spring chamber 3 is controlled by one valve. On the other hand, suspension unit S
The exhaust route from is indicated by a dashed arrow. That is, the exhaust from the suspension units FS1 and FS2 is routed through the solenoid valves 22 and 23, the exhaust flow rate control valve 27, the exhaust direction switching valve 28, and the residual pressure valve 29 to the low pressure side reserve tank 15b.
sent to. In addition, the suspension unit
Exhaust from FS1 and FS2 is solenoid valve 2
2, 23, the exhaust flow rate control valve 27, the exhaust direction switching valve 28, the dryer 13, the exhaust solenoid valve 30, and the air cleaner 12 to be released to the atmosphere. In addition, suspension unit RS1,
Exhaust from RS2 uses solenoid valves 25 and 26,
It is sent to the low pressure side reserve tank 15b via the exhaust flow rate control valve 27, exhaust direction switching valve 28, and residual pressure valve 29. Note that when the pressure in the reserve tank 15b is lower than the pressure in the air spring chamber 3, the residual pressure valve 29 is in an open state, and when the pressure in the reserve tank 15b is higher than the pressure in the air spring chamber 3, the residual pressure valve 29 is in a closed state. Become. Furthermore, the exhaust from the suspension units RS1 and RS2 is controlled by solenoid valves 25 and 26, an exhaust flow rate control valve 27, an exhaust direction switching valve 28, and a dryer 1.
3. Exhaust solenoid valve 30, air cleaner 1
2 to the atmosphere. Front right solenoid valve 22, front left solenoid valve 23, rear right solenoid valve 25,
A fluid discharge device is constituted by the rear left solenoid valve 26, the exhaust flow rate control valve 27, the exhaust direction switching valve 28, and the reserve tire 15b. Solenoid valve 22, 23, 25, 26
Each of the solenoid valves is composed of a three-way valve, and when each solenoid valve is in the OFF state, fluid can be supplied to the fluid spring chamber 3, and the fluid spring chambers 3 of the left and right suspension units are communicated with each other.
Further, when each solenoid valve is in the ON state, fluid can be discharged from the fluid spring chamber 3, and the fluid spring chambers 3 of the left and right suspension units are disconnected from each other. In this way, each solenoid valve controls the supply and discharge of fluid to each fluid spring chamber 3 by one valve.

Further, 31 is a vehicle height sensor, and this vehicle height sensor 3
Reference numeral 1 denotes a front vehicle height sensor 31F that is attached to the lower arm 32 of the front right suspension of the automobile to detect the front vehicle height of the automobile, and a front vehicle height sensor 31F that is attached to the lateral rod 33 of the rear left suspension of the automobile to detect the rear vehicle height of the automobile. The rear vehicle height sensor 31R detects the height of the vehicle, and detection signals are supplied from these vehicle height sensors 31F and 31R to a control unit 34 serving as a vehicle height adjustment control section.

Each sensor 31F, 31 in the vehicle height sensor 31
R is designed to detect the distance from the normal vehicle height level, the low vehicle height level, or the high vehicle height level, respectively.

Furthermore, the speedometer has a built-in vehicle speed sensor 35, which detects the vehicle speed and transmits the detection signal to the control unit 3.
4. The control unit 34 is composed of, for example, a microcomputer, and has a V +
A control time determining means is provided that determines the valve driving time by referring to a map memory that determines the valve driving time Tp with respect to αV'.

Further, a differential transformer type G sensor 36 is provided as a vehicle body posture sensor for detecting changes in the posture of the vehicle body. The configuration of this differential transformer type G sensor will be described later using FIG. 2.

Further, numeral 37 is an indicator for displaying oil pressure, and the display of this indicator 37 is controlled by the control unit 34. A steering sensor 38 detects the rotational speed of the steering wheel 39, that is, the steering speed, and its detection signal is sent to the control unit 34. Furthermore, 4
0 is an accelerator opening sensor (not shown) that detects the depression angle of an accelerator pedal of the engine, and its detection signal is sent to the control unit 34. Further, 41 is a compressor relay for driving the compressor 11, and this compressor relay 41 is controlled by a control signal from the control unit 34. Furthermore, 42 is a pressure switch that is turned on when the pressure in the reserve tank 15a falls below a predetermined value, and its output signal is output to the control unit 34. That is, when the pressure in the reserve tank 15a falls below a predetermined level, the pressure switch 34 is turned on, and the compressor relay 41 is operated under the control of the control unit 34. As a result, compressor 1
1 is driven, compressed air is sent into the reserve tank 15a, and the pressure inside the reserve tank 15a is increased to a predetermined value or higher. The opening and closing of the solenoid valves 19, 22, 23, 25, 26, 30 and the valves 20, 27, 28 are controlled by control signals from the control unit 34.

Next, the differential transformer type G sensor 36 of FIG. 1 will be explained with reference to FIG. In FIG. 2, 51 is the sensor body. This sensor body 5
1 is filled with buffer oil 52.
Springs 53a and 53b are attached to the protrusion 51a within the sensor body 51, and a core 54 is supported by a support member 55 and suspended from the lower ends of the springs 53a and 53b.
Further, 56 is a printed circuit board whose upper end is attached to the convex portion 51a and whose lower end is attached to the coil assembly 57. A primary coil 57a and a secondary coil 57b are wound around the coil assembly 57.

Note that FIG. 3 is a diagram showing an electrical equivalent circuit of the differential transformer type G sensor 36 shown in FIG. 2.
That is, the printed circuit board 56 includes an oscillator 61,
A drive circuit 62 and an AC/DC converter 63 are mounted, and when the core 54 is displaced in the longitudinal or lateral direction due to acceleration G in the longitudinal or lateral direction, the output voltage VG of the converter 63 changes according to the amount of displacement. Here, FIG. 4 shows an example of the output voltage VG of the G sensor 36. As shown in the figure, as the acceleration G increases, the voltage VG increases in proportion to it.

Next, the operation of an embodiment of the present invention configured as described above will be explained. In this embodiment, the handle 39
This is about the left roll when the vehicle is steered to the right.
First, in step S11, the output voltage V+ corresponds to the acceleration in the left and right direction output from the G sensor 36.
α・Time differential value V′ is the control unit 34
is read into. Then, the process proceeds to step S12, where the V+αV' map stored in the control unit 34 is referred to, and the valve drive time Tp is determined. Next, proceed to step S13 and control time T=Tp
−Tm is calculated. Here, Tm has an initial value of 0
is set to . The process then proceeds to step S14, where the content of the above T is determined. This step S14
If it is determined that "T>0" in step S15
Proceed to. In this step S15, the air supply solenoid valve 19, solenoid valve 22, and solenoid valve 25 are turned on for the above-mentioned control time T by a control signal from the control unit 34.
That is, the compressed air sent from the reserve tank 15a is supplied to the front left suspension unit FS1 via the air supply solenoid valve 19, the air supply flow control valve 20, the check valve 21, and the solenoid valve 23. At the same time, compressed air from the reserve tank 15a is sent to the rear left suspension unit RS1 via the air intake solenoid valve 19, air intake flow rate control valve 20, check valve 24, and solenoid valve 26. On the other hand, the compressed air discharged from the air spring chamber 3 of the suspension unit FS2 on the front right side is supplied to the solenoid valve 22 and the exhaust flow control valve 2.
7. It is discharged into the reserve tank 15b via the exhaust direction switching valve 28 and the residual pressure valve 29. Furthermore, the compressed air discharged from the air spring chamber 3 of the rear right suspension unit RS2 is discharged to the reserve tank 15b via the solenoid valve 25, exhaust flow control valve 27, exhaust direction switching valve 28, and residual pressure valve 29. . In this way,
The vehicle body can be kept level when the steering wheel is turned to the right. When the process in step S15 is completed, the process advances to step S16, where only the air supply solenoid valve 19 is closed. As a result, the state of attitude control in step S15 is maintained.
Then, the process advances to step S17, and the contents of the map memory are updated. In other words, Tp is set to Tm. Then, when the steering wheel is turned to the right,
Voltage V+α・differential value output from G sensor 36
Since V' is less than the predetermined value (ie, a in FIG. 6), the determination in step S18 is ``YES'' and the process proceeds to step S19. In this step S19, the solenoid valves 22 and 25 are turned off, and the fluid spring chamber 3 on the right side of the front wheel communicates with the fluid spring chamber 3 on the left side of the front wheel, and the fluid spring chamber 3 on the right side of the rear wheel and the fluid spring chamber 3 on the left side of the rear wheel communicate with each other. Communication is established with the fluid spring chamber 3, and posture control is released. In this way, V+
Since the valve release time is changed according to the magnitude of αV', fine-grained attitude control can be performed.

[Effects of the invention] As detailed above, according to the invention, it is possible to use valves with simple opening and closing functions as supply valves and discharge valves without using complicated servo mechanisms as in the conventional device. To provide an electronically controlled suspension device that controls the supply and discharge of fluid in a fluid spring chamber at appropriate timing according to the situation of increase in lateral acceleration and up to the supply and discharge amount corresponding to the maximum lateral acceleration. I can do it.

In other words, when a vehicle shifts from driving straight to turning, in normal driving the steering wheel is turned and held in that state, but the lateral acceleration acting on the vehicle body gradually increases. It may increase rapidly. Furthermore, if the turning radius suddenly becomes smaller or the vehicle speed suddenly increases during a turn, the lateral acceleration acting on the vehicle body may suddenly increase.

In the present invention, even after the control is executed once during a turn, if the lateral acceleration acting on the vehicle body increases, additional control of the valve control time T is executed to correspond to the increase. Therefore, when the vehicle shifts from straight-ahead running to turning direction and the lateral acceleration gradually increases, the amount of fluid supplied and discharged increases step by step as the lateral acceleration increases, eventually reaching the maximum lateral acceleration. Since the amount of supply and displacement increases to match the amount of supply and displacement, the control becomes extremely smooth and the amount of roll of the vehicle body can be sufficiently reduced without causing any discomfort to the occupants. In addition, when the steering wheel is suddenly turned while driving straight and the lateral acceleration suddenly increases, the supply and displacement amount increases as quickly as possible to match the maximum lateral acceleration, so there is no control delay and the vehicle rolls. can be sufficiently reduced. Additionally, if the vehicle is turning while maintaining a certain steering angle, the control will be executed for a control time commensurate with the lateral acceleration at that time, but if the steering wheel is turned further from the turning state, the lateral acceleration increases. When this happens, additional control is executed with an additional supply/discharge amount commensurate with the increase.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an electronically controlled suspension device according to the present invention, Fig. 2 is a sectional view of a differential transformer type G sensor, and Fig. 3 is a diagram showing an electrical equivalent circuit of the differential transformer type G sensor. , FIG. 4 is a diagram showing the output voltage of the differential transformer type G sensor, FIG. 5 is a flowchart showing the operation of an embodiment of the present invention, and FIG. 6 is a diagram showing a V+αV' map. 15a, 15b... Reserve tank, 19...
Air supply solenoid valve, 20... Air supply flow rate control valve, 22, 23, 25, 26... Solenoid valve, 27... Exhaust flow rate control valve, 28... Exhaust direction switching valve, 29... Residual pressure valve, 30... …
Exhaust solenoid valve, 34...control unit, 36...differential transformer type G sensor.

Claims (1)

[Scope of utility model registration request] a fluid spring chamber interposed between the wheel and the vehicle body;
a fluid supply device that supplies fluid to the fluid spring chamber via a supply valve; a fluid discharge device that discharges fluid from the fluid spring chamber via a discharge valve; and a signal responsive to horizontal acceleration acting on the vehicle body. and a control time determining means for determining a valve control time T according to the output of the acceleration sensor, and during the valve control time T determined by the control time determining means, the above a controller that outputs a control signal to open a supply valve of a fluid spring chamber and a discharge valve of the fluid spring chamber on the inner side of the swing; The control time determining means includes means for determining the control time Tp by referring to the control time map according to the output of the acceleration sensor, and a map memory for storing the previously determined and already executed control time Tm. The present invention is characterized in that when the time obtained by subtracting the control time Tm stored in the map memory from the control time Tp obtained by referring to the time map is a positive value, the subtracted time is determined as the valve control time T. Electronically controlled suspension device.