JPH0345843Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an electronically controlled suspension device having a vehicle height adjustment function.

[Technical background of the invention and its problems] The idea was to create an electronically controlled suspension device that has a vehicle height adjustment function that adjusts the vehicle height by adjusting the fluid pressure in the fluid spring chambers of the suspension units installed on each left and right wheel. It is being In such devices, the vehicle height is averaged at predetermined time intervals (so-called vehicle height determination time), and the vehicle height is electronically controlled to lower or raise depending on whether the average vehicle height is higher or lower than the target vehicle height. controlled. Furthermore, by making the vehicle height determination time when the vehicle is stopped shorter than when the vehicle is running, the vehicle height can be quickly adjusted when a passenger gets on or off the vehicle when the vehicle is stopped. However, since the spring reaction force of the fluid spring chamber of such a device is small, operating the brake or accelerator while the vehicle is stopped and the vehicle height determination time is short will cause the vehicle height to change, resulting in frequent vehicle height adjustments. There are drawbacks. To prevent this, a stop logic is considered that prohibits vehicle height adjustment under certain conditions while the vehicle is stopped. In other words, while the stop logic is satisfied, vehicle height adjustment is prohibited even when the vehicle is stopped. Therefore, when the vehicle is stopped and the vehicle height holds true, it is necessary to quickly cancel the vehicle height and adjust the vehicle height when a passenger gets on or off the vehicle, which inevitably causes a change in vehicle height.

[Purpose of invention]

The present invention was devised in view of the above points, and its purpose is to establish a stop logic when stopping and prevent unnecessary vehicle height adjustments when stopped. To provide an electronically controlled suspension device which cancels stop logic and quickly adjusts the vehicle height when the vehicle height needs to be adjusted due to getting on and off the vehicle.

[Summary of the idea]

It has a vehicle height adjustment function that adjusts the vehicle height by adjusting the fluid pressure in the fluid spring chamber of the suspension unit provided on each left and right wheel, and establishes a stop logic that prohibits the vehicle height adjustment function when the vehicle is stopped. This is an electronically controlled suspension device that cancels the stop logic when the door is opened and quickly adjusts the vehicle height.

[Example of idea]

An embodiment of this invention will be described below with reference to the drawings. FIG. 2 is a schematic diagram of a car equipped with this device.

As shown in Fig. 2, 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 interposed, and rear air suspension units RS, RS1, and RS2 are installed between both left and right ends of the rear wheel BA side axle and the vehicle body B side member, 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 Figure 1, 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 slot-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 It has a piston that is slidably inserted into the cylinder, and the cylinder moves up and down with respect to the piston rod 2 in response to the up and down movement of the wheel, thereby exerting a damping function that corresponds to the position of the shutter in the shock absorber 1. , it is now able to absorb shots 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, a sub 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. , 6b is loaded with a coil spring 7.

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 auxiliary air spring chamber 5 can be brought into communication with each other to make the spring constant small (soft). The spring constant can be made large (hard) by putting the room 5 in a shielding state.

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. 1, 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 designed to be 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 the suspension unit S via an air supply solenoid valve 21.

Further, as shown in FIG. 1, a vehicle height sensor 22 is provided, and this vehicle height sensor 22 is attached to the 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 the vehicle body posture such as pitch, roll, and yaw on the car's springs. 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 the pneumatic drive mechanism 35 and the atmosphere can be selected, and this has the function of rotating the control rod 3 in the opposite direction to a predetermined position and shifting from the soft state to the hard state. . Further, 37 is a foot brake switch that detects depression of the foot brake, and 38 is a door switch that detects opening/closing of the door. Note that it is also possible to use an air cylinder type drive mechanism instead of the solenoid type drive mechanism 20. Furthermore, the symbol LF indicates the boundary between the engine room (to the 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 (to the right of the broken line LR). There is. Reference numeral 30 indicates a bump 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, this mode selection switch 31 can 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.

Next, the operation of an embodiment of the present invention constructed as described above will be explained with reference to the flowchart of FIG. The process shown in the flowchart of FIG. 3 is carried out by the control unit 25, and first, in step S1, it is determined whether or not the vehicle has stopped. This is because a signal from the vehicle height sensor 27 detects that the vehicle speed is 3 km/h or less. If the result of step S1 is ``YES'', the process proceeds to step S2, where it is determined whether the vehicle has just stopped. In other words, the vehicle speed is 3km/h
It is determined whether it has just become below. If the determination in step S2 is ``YES'', the process advances to step S3 and vehicle height adjustment is prohibited for 6 seconds. The process then proceeds to step S4, where the vehicle height data output from the vehicle height sensor 27 after the lapse of six seconds is compared with the immediately preceding vehicle height data. And step S
Proceeding to step 5, it is determined whether the two are equal. If the determination in step S5 is ``YES'', the process proceeds to step 6, where the stop logic is established. Vehicle height adjustment is prohibited for 6 seconds after the vehicle stops due to the processing in step S3, but once this stop logic is established, vehicle height adjustment is prohibited thereafter until the stop logic is canceled.

By the way, if "NO" is selected in step S2,
In other words, even if it is determined that the car is stopped, if the foot brake is depressed (the foot brake switch 37 is on), or if the vehicle speed pulse is sent from the vehicle speed sensor 27 to the control unit 2.
5 or the accelerator sensor 34
If the accelerator operation speed detected by the above is equal to or higher than the predetermined value, a ``YES'' determination is made in steps S7 to S9, and the process returns to step S3.

On the other hand, if the answer in step S5 is "NO", then after the process in step S6 is completed, the answer is "NO" in step S9.
If it is determined “NO” in step S10
Proceed to. In this step S10, it is determined whether or not the stop logic is being established. If it is determined "YES" in this step S10, the process proceeds to step S11.
If the determination is ``YES'' in step S14, the process advances to step S15 and the stop logic is canceled.
In other words, the prohibition of vehicle height adjustment is lifted and vehicle height adjustment is quickly performed. In other words, the above step S11
In step S12, the vehicle height signals output from the vehicle height sensors 22F and 22R are determined to be less than or equal to LL. When the vehicle starts running in step S13, that is, it is determined that the vehicle speed is 3 km/h or more based on the signal from the vehicle speed sensor 27, or it is detected that the door is opened by the door switch 38 in step S14, the stop logic is canceled in step S15. . In other words, when it is detected that the door has opened and it is determined that an occupant is getting in and out of the vehicle, the stop logic is canceled and the vehicle height is adjusted.

Next, the operation of another embodiment of the present invention constructed as described above will be explained with reference to the flowchart of FIG. The process in the flowchart of FIG. 4 is carried out by the control unit 25, and first, in step S21, it is determined whether or not the vehicle has stopped. This is because a signal from the vehicle speed sensor 27 detects that the vehicle speed is 3 km/h or less. "YES" in this step S21
If it is determined that this is the case, the process proceeds to step S22, where it is determined whether or not the vehicle has just stopped. In other words, it is determined whether or not the vehicle speed has just fallen below 3 km/h.
If the determination in step S22 is ``YES'', the process advances to step S23 and vehicle height adjustment is prohibited for 6 seconds. The process then proceeds to step S24, where the vehicle height data outputted from the vehicle height sensor 27 after the lapse of six seconds is compared with the immediately preceding vehicle height data.
Then, the process proceeds to step S25, where it is determined whether or not the two are equal. If the determination in step S25 is ``YES'', the process proceeds to step 26, where the stop logic is established. Vehicle height adjustment is prohibited for 6 seconds after the vehicle stops due to the processing in step S23, but once this stop logic is established, vehicle height adjustment is prohibited thereafter until the stop logic is canceled.

By the way, in the above step S22,
Even if it is determined that the vehicle is stopped, the foot brake is depressed (the foot brake switch 37 is on), or the vehicle speed pulse is input from the vehicle speed sensor 27 to the control unit 25. or when the accelerator operation speed detected by the accelerator sensor 34 exceeds a predetermined value, steps S27 to S
In step S29, the determination is ``YES'' and the process returns to step S23.

On the other hand, if "NO" is selected in step S25,
After the processing in step S26 is completed, if the determination in step S29 is "NO", the process proceeds to step S30. In this step S30, it is determined whether or not the stop logic is being established. This step S
If ``YES'' is determined in step S30, and ``YES'' is determined in steps S31 to S33, the vehicle height calculation start time is delayed by 6 seconds in step S34, and then the process advances to step S35, where the stop logic is canceled. The processing in step S34 above means that the start of vehicle height adjustment is delayed by 6 seconds. In other words, the vehicle height signals output from the vehicle height sensors 22F and 22R in step S31 are H.
or the vehicle height signals outputted from the vehicle height sensors 22F and 22R in step S32 are determined to be less than or equal to LL.
3, when the door switch 38 detects that the door is open, the stop logic is canceled in step S35 after the process in step S34.

On the other hand, in step S36, the answer is "YES", that is, the vehicle speed is 3 km/h due to the signal from the vehicle speed sensor 27.
If it is determined that the vehicle height is greater than or equal to h (driving start), the vehicle height calculation start time is delayed by 12 seconds in step S37, and then the process proceeds to step S35. In other words, the processing in step S37 above means that the start of vehicle height adjustment is delayed by 12 seconds. in this way,
The delay time is extended to 12 seconds when the stop logic is canceled after the car starts running. This prevents the vehicle height from being frequently adjusted in response to changes in vehicle height, although the vehicle height tends to change after the vehicle starts traveling.

Furthermore, since the opening of the door is delayed by only 6 seconds, which is shorter than when the vehicle starts traveling, the vehicle height adjustment can be started earlier than when the stop logic is canceled after the vehicle has started traveling. Also, the meaning of delaying in this way is that after the stop logic is released, the average vehicle height is immediately calculated using the vehicle height average time according to the predetermined vehicle speed. All past vehicle height data detected while the stop logic is activated is returned to the normal position. (While the stop logic is activated, the vehicle height is always higher or lower than normal.)
However, this is to prevent vehicle height adjustment from being started due to this.

[Effect of idea]

As described in detail above, the present invention has a vehicle height adjustment function that adjusts the vehicle height by adjusting the fluid pressure in the fluid spring chamber of the suspension unit provided on each left and right wheel. In the electronically controlled suspension system, which has a stop logic that prohibits the adjustment function, the stop logic is canceled when the door opens, so the vehicle height can be adjusted quickly when the door opens and a passenger gets on and off. It is possible to provide an electronically controlled suspension device that allows adjustments to be made.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an electronically controlled suspension device according to an embodiment of the present invention, Fig. 2 is a diagram showing the mounting position of the suspension, and Fig. 3 is a flowchart showing the operation of an embodiment of the present invention. , FIG. 4 is a flowchart showing the operation of another embodiment of the present invention. 22F, 22R...Vehicle height sensor, 25...Control unit, 27...Vehicle speed sensor, 34...
...Accelerator sensor, 37...Foot brake switch, 38...Door switch.

Claims (1)

[Scope of utility model registration request] It has a vehicle height adjustment function that adjusts the vehicle height by adjusting the fluid pressure in the fluid spring chambers of the suspension units installed on each side, and establishes a stop logic that prohibits the vehicle height adjustment function when the vehicle is stopped. The electronically controlled suspension device is characterized by comprising door opening/closing detection means for detecting opening/closing of the door, and means for canceling the stop logic when the door opening/closing detection means detects that the door is opened. electronically controlled suspension device.