JPH036486Y2 - - Google Patents

Description

[Detailed explanation of the idea]

This invention relates to an electronically controlled suspension device that adjusts the vehicle height by adjusting the amount of fluid in a fluid spring chamber. For vehicles equipped with a type of suspension, such as a trailing arm (including semi-trailing arm) or a leading arm, in which the longitudinal position of the wheel relative to the vehicle body changes when the wheel moves up and down, all wheels can be adjusted by pressing the foot brake. When the vehicle is locked, the distance between the front and rear wheels does not change due to friction between each wheel and the road surface, resulting in a problem that the suspension is locked and the vehicle height cannot be adjusted. In particular, in a hydraulic vehicle height adjustment device that adjusts the vehicle height by adjusting the amount of fluid in a fluid spring chamber provided for each suspension unit, when the vehicle height is adjusted by stepping on the foot brake, the suspension changes. Even though the vehicle is locked, the pressure in the fluid spring chamber increases, and when the foot brake is released, the vehicle height suddenly rises, causing discomfort to the occupants. This idea was made in view of the above points,
The purpose of this system is to adjust the vehicle height by adjusting the amount of fluid in the fluid spring chamber provided in each suspension unit. An object of the present invention is to provide an electronically controlled suspension device that prohibits the following. An embodiment of this invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a car equipped with this device. As shown in Fig. 1, front air suspension units FS, FS1, and FS2 are installed between the left and right ends of the front wheel FA side axle and the vehicle body B side member, respectively.
are installed, and rear air suspension units RS, RS1, and RS2 are installed between the left and right ends of the rear BA side wheels and the vehicle body B side members, respectively.
is interposed. These air suspension units FS1,
Since FS2, RS1, and RS2 each have almost the same structure, air suspension units will be referred to by reference numerals as shown in Fig. 2, unless the front and rear suspension units are explained separately. S
The explanation will be made using the following figure, and only the parts necessary for vehicle height control will be illustrated and explained. That is, these air suspension units S incorporate a strut type damping force switching type shock absorber 1, and this shock absorber 1 has a cylinder attached to the front wheel FA side or the rear wheel BA side, and this The cylinder is equipped with a piston that is slidably inserted into the cylinder, and the cylinder moves up and down with respect to the piston rod 2 in accordance with the up and down movement of the wheel, thereby creating a shock absorber 1.
It has a damping function depending on the position of the shutter inside, allowing it to absorb shock effectively. Incidentally, a main air spring chamber 3 which also serves as a vehicle height adjustment fluid chamber is disposed coaxially with the piston rod 2 at the top of the shock absorber 1.
Since a part of the main air spring chamber 3 is formed by a bellows 4, the piston rod 2 can be moved up and down by supplying and discharging air to the main air spring chamber 3. Further, an auxiliary air spring chamber 5 is disposed coaxially with the piston rod 2 directly above the main air spring chamber 3. Further, the outer wall of the shock absorber 1 is provided with a spring receiver 6a facing upward, and the outer wall of the auxiliary air spring chamber 5 is provided with a spring receiver 6b facing downward. A coil spring 7 is loaded between 6a and 6b. Further, these air spring chambers 3 and 5 are connected to each other via a communication passage 9 bored in a control rod 8 which is rotatably inserted into the piston rod 2. An on-off valve 10 constituting a spring constant switching mechanism is interposed therein. This on-off valve 10 is connected to the auxiliary air spring chamber 5 and the communication passage 9.
The main air spring chamber 3 is configured to include a first valve portion 10a that cuts off communication between the main air spring chamber 3 and the communication passage 9, and a second valve portion 10b that cuts off communication between the main air spring chamber 3 and the communication passage 9. Therefore, when the on-off valve 10 is in the open mode,
The main air spring chamber 3 and the sub-chamber air spring chamber 5 can be brought into communication to make the spring constant small (soft), and when the on-off valve 10 is in the close mode, the main air spring chamber 3 and the sub-chamber By cutting off the air spring chamber 5, the spring constant can be increased (hardened). That is, by rotating the control rod 8, the on-off valve 10 can be opened and closed.
By opening and closing, the spring chamber capacity can be changed. By changing this spring chamber capacity, the spring constant of the suspension can be changed. Further, the lower end of the control rod 8 is provided with a control valve 8a that can change the orifice area of the piston 1a of the shock absorber 1. This control valve 8a is operated by the piston 1a when the on-off valve 10 is in the open mode by the control rod 8.
By increasing the orifice area and reducing the damping force,
When the on-off valve 10 is in the closed mode, the orifice area of the piston 1a is reduced to increase the damping force. Thus, the vehicle height adjustment of the automobile is carried out by the configuration shown in FIG. That is, as shown in FIG. 2, compressed air for adjusting the vehicle height is transmitted from a compressor 11 as a compressed air generating device to a dryer 12,
Each suspension unit is It is now supplied to S. The compressor 11 compresses the air sent from the air cleaner 18 and supplies the compressed air to the dryer 12. The compressed air dried by silica gel or the like in the dryer 12 is shown by the solid line arrows in FIG. Like, suspension unit S
supplied to Furthermore, when compressed air is exhausted from the suspension unit S, the exhaust solenoid valve 1 is
Via 9, the compressed air is released to the atmosphere. Note that the dryer 12 includes a reserve tank 20.
A portion of the compressed air is supplied from this reserve tank 20 to each suspension unit S via an air supply solenoid valve 21. Further, as shown in FIG. 2, a vehicle height sensor 22 is provided, and this vehicle height sensor 22 is attached to a lower arm 23 of the front right suspension of the vehicle to detect the front vehicle height of the vehicle. The vehicle height sensor 22F includes a height sensor 22F and a rear vehicle height sensor 22R that is attached to the lateral rod 24 of the rear left suspension of the vehicle and detects the rear vehicle height of the vehicle.
A front vehicle height detection signal and a rear vehicle height detection signal are supplied from 2F and 22R to a control unit 25 serving as a vehicle height adjustment control section. Each sensor 22F, 22 in the vehicle height sensor 22
R is the Hall IC element and one of the magnets connected to the wheel FA.
and the other side is attached to the vehicle body B side to detect the distance from the normal vehicle height level and the low vehicle height or high vehicle height level, respectively. Note that the vehicle height sensor may be of any other type, for example, one using a phototransistor. Furthermore, the speedometer 26 has a built-in vehicle speed sensor 27, which detects the vehicle speed and sends a detection signal to the control unit 2.
Mechanical speedometers use a reed switch type vehicle speed sensor, and electronic speedometers use a transistor-based open collector output type sensor. Further, an acceleration sensor 28 is provided as a vehicle body posture sensor that detects changes in the posture of the vehicle body.
This acceleration sensor 28 is designed to detect changes in pitch, roll, and yaw of the vehicle body posture on the automobile spring. For example, when there is no acceleration, the weight is in a hanging state, and the light from the light emitting diode is directed toward the shielding plate. The structure is such that the absence of acceleration can be detected by blocking the light from reaching the photodiode. When acceleration acts in the front and back, left and right, or up and down directions, the weight tilts or moves, and the acceleration state of the vehicle body is detected. A steering sensor 32 detects the rotational speed of the steering wheel 33, that is, the steering speed.
4 is an accelerator sensor (not shown) that detects the operating speed of the accelerator pedal of the engine; 35 is a pneumatic drive mechanism that is connected to the reserve tank 20 via a three-way switching valve 36 and rotates the control rod 8; The direction switching valve 36 is located at a position where the pneumatic drive mechanism 35 and the reserve tank 20 are communicated with each other by a signal from the control unit 25;
Either one of the positions communicating between the pneumatic drive mechanism 35 and the atmosphere can be selected, and this has the function of rotating the control rod 8 in the opposite direction to a predetermined position and shifting from the soft state to the hard state. . Note that an air cylinder type drive mechanism may be used instead of the solenoid type drive mechanism 20. Furthermore, the symbol LF indicates the boundary between the engine room (left of the broken line LF) and the passenger compartment (between the broken lines LF and LR), and LR indicates the border between the passenger compartment and the trunk room (between the broken lines LF and LR).
(to the right of LR). Also code 3
0 indicates a pump stopper for preventing damage to the wall surface of the main air spring chamber 3 due to the relative rise of the cylinder of the shock absorber 1 on rough roads or the like. Reference numeral 31 is a mode selection switch serving as a high vehicle height selection switch. By the way, as shown in the table, this mode selection switch 31 is used to switch between an auto mode in which the vehicle height is automatically controlled to a normal vehicle height or a low vehicle height, and a high mode in which the vehicle height is controlled to a high vehicle height. I can do it. For example, as shown in the table below, if the mode selection switch 31 is set to auto mode and the vehicle speed continues to be 90 km/h or higher for 10 seconds or more during acceleration, the vehicle height will automatically become low. controlled by.

[Table] Next, the operation of this invention configured as described above will be explained. The control unit 25 shown in FIG. 2 performs the processing shown in the flowchart of FIG. First, in step S1, it is determined whether the manual switch, that is, the mode selection switch 31, is turned on, that is, switched. If the determination in step S1 is ``YES'', the process proceeds to step S2, where the vehicle speed sensor 2
Based on the signal output from 7, it is determined whether the vehicle speed is 3 km/h or less. This step S2 is for determining whether the vehicle speed is determined to be 3 km/h or less. If the determination in step S2 is ``YES'', the process advances to step S3. In this step S3, it is determined whether or not the foot brake has been depressed. This step S
If ``YES'' is determined in step 3, step S
Proceed to step 4 and the setting of the target vehicle height is put on hold. That is, even if the mode selection switch 31 is switched, when the vehicle is stopped and the foot brake is depressed, the setting of the target vehicle height is suspended and vehicle height adjustment is prohibited. By the way, after the mode selection switch 31 is switched, the determination in step S1 is ``NO'' and the process proceeds to step S5. In step S5, it is determined whether the setting of the target vehicle height is pending. If the process in step S4 is being performed as described above, the determination in step S5 is ``YES'' and the process proceeds to step S2. Below, step S2 or S3
If the determination is "NO" in step S6, the target vehicle height is set. This step S6
The process is set to auto mode when high mode was selected last time, and to high mode when auto mode was selected last time. That is, each time the mode selection switch 31 is operated, the high mode and auto mode are alternately set. In other words, even if the mode selection switch 31 is changed, the target vehicle height will be changed when the car is stopped and the foot brake is depressed. Even when the vehicle is stopped, the target vehicle height is set when the foot brake is no longer depressed. Thereafter, the vehicle height is adjusted to reach this target vehicle height. Next, the operation of another embodiment of this invention will be explained. Control unit 2 shown in Figure 2
5, the processing shown in the flowchart of FIG. 4 is performed. First, in step S1, it is determined whether the manual switch, that is, the mode selection switch 31, is turned on, that is, switched. If the determination in step S11 is ``YES'', the process proceeds to step S12, where it is determined based on the signal output from the vehicle speed sensor 27 whether the vehicle speed is 3 km/h or less. In this step S12, it is determined whether the vehicle speed is 3 km/h or less, but the meaning of this step is to determine whether the vehicle is stopped. If the determination in step S12 is ``YES'', the process advances to step S13. In this step S13, it is determined whether or not the brake has been depressed. This step S13
If the determination is ``YES'' in the step, the process ends. That is, when the car is stopped and the foot brake is depressed, the target vehicle height is not set even if the mode selection switch 31 is switched. On the other hand, if the determination in step S2 or S3 is "NO", the process proceeds to step S14, where the target vehicle height is set. That is, when the high mode was selected last time, the auto mode is set, and when the auto mode was selected last time, the high mode is set. In other words, mode selection switch 3
Each time 1 is switched, high mode and auto mode are set alternately. That is, in this embodiment, when the vehicle is stopped and the foot brake is depressed, the target vehicle height is not set and vehicle height adjustment is prohibited.
On the other hand, after the target vehicle height is set in step S14, the vehicle height is adjusted. As detailed above, according to this invention, the suspension is of a type in which when the wheel moves up and down, the position of the wheel in the longitudinal direction relative to the vehicle body is displaced, and the amount of fluid in the fluid spring chamber provided for each suspension unit is provided. In a hydraulic vehicle height adjustment device that adjusts the vehicle height by adjusting the target vehicle height, when the car is stopped and the foot brake is depressed, vehicle height adjustment based on the target vehicle height is prohibited, so the vehicle height adjustment device that adjusts the vehicle height based on the target vehicle height is prohibited. When released, it is possible to prevent the vehicle height from rising suddenly and causing discomfort to the occupants.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a car equipped with this device, Fig. 2 is an overall configuration diagram of this device, Fig. 3 is a flowchart for explaining the operation of one embodiment, and Fig. 4 is a diagram of another embodiment. This is a flowchart for explaining the operation of an example. 11...Compressor, 25...Control unit, 27...Vehicle speed sensor, 31...Mode selection switch.

Claims (1)

[Scope of utility model registration request] The hydraulic type is equipped with a type of suspension that changes the longitudinal position of the wheel relative to the vehicle body when the wheel goes up and down, and the vehicle height can be adjusted by adjusting the amount of fluid in the fluid spring chamber provided for each suspension. The vehicle height adjustment device includes a switch means for switching the target vehicle height, a vehicle height adjustment means for adjusting the vehicle height based on the target vehicle height given by the switch means, and a vehicle height adjustment means for adjusting the vehicle height based on the target vehicle height given by the switch means, and when the vehicle speed is lower than the set vehicle speed and the foot brake is depressed. An electronically controlled suspension device comprising: means for prohibiting vehicle height adjustment based on the target vehicle height given by the switch means.