JPH04189615A - Car floor height adjusting device - Google Patents

Abstract

PURPOSE:To prevent the malfunction in adjusting car floor height without enlarging equipment or making procedure complex by changing calculation time for determining an average car floor height for a clopped car to the specified short time and changing the calculation time to the specified time longer than the time for a stopped car, when the car is running. CONSTITUTION:An actuator a varies the stroke between a car body and each wheel by charging and discharging fluid. On the other hand, a means B detects the stroke between the car body and each wheel at each wheel position, and a means C averages the values detected by the means B in changeable calculation time. A means D controls the actuator A when the values calculated by the means C are out of the range of objective car height. In such a device, a means E judges whether the car is stopping or running. If the means E judges that the car is stopping, the aforementioned calculation time is changed to a short time, in which the change of car height can be sensed, by a means F. In addition, if, the means E judges that the car is running, the aforementioned calculation time is changed to the longer time than the time for a stopped car by a means G.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vehicle height adjustment device, and in particular, an actuator such as a hydraulic cylinder whose stroke can be changed by supplying fluid is disposed at each wheel position. Related to vehicle height adjustment device.

[Conventional technology]

Conventionally, this type of vehicle height adjustment device is known, for example, as disclosed in Japanese Patent Application Laid-Open No. 62-283011, which was previously proposed by the present applicant.

In this conventional device, the actuator part is a suspension device in which a fluid chamber capable of supplying and discharging fluid is arranged at each wheel position, a vehicle height detecting means for detecting the vehicle height, and an average value of the detected vehicle height values, for example, a moving average. It has a vehicle height average value calculating means that calculates by processing, determines the height of the calculated vehicle height average value, and supplies and discharges fluid to and from the fluid supply source according to the determination result, while the vehicle body It has a vehicle body attitude change detection means for detecting or estimating a change in attitude, and it is determined whether or not the attitude change is large based on the detection value of this detection means, and when it is determined that the attitude change is large, the vehicle height is It is shown whether the configuration is such that control is prohibited. This prevents a malfunction in which when the posture changes significantly during a roll, nose dive, or scut, the vehicle height is adjusted incorrectly due to a misunderstanding that the vehicle height has changed.

[Invention or problem to be solved]

However, in the configuration shown in the conventional example described above, while the calculation time (i.e., control sensitivity) for calculating the average vehicle height value is constant regardless of whether the vehicle is stopped or running,
Since it is essential to detect or estimate posture changes when turning and accelerating/decelerating, a longitudinal acceleration sensor and a lateral acceleration sensor, or sensors capable of estimating these posture changes, are required, and the equipment is large and large. As it takes shape,
This has the disadvantage that the processing procedure becomes complicated.

The present invention was made in view of this situation,
Vehicle body changes such as roll, dive, and scut occur while the vehicle is running, and vehicle height changes due to changes in load due to passengers getting on and off or loading and unloading cargo occur while the vehicle is stopped. By focusing on the fact that it is possible to accurately determine whether vehicle height adjustment is truly necessary by changing the control sensitivity depending on the The purpose of this is to prevent malfunctions in vehicle height adjustment caused by changes in posture.

[Means to solve the problem]

In order to achieve the above object, the present invention, as shown in FIG. 1, includes an actuator that can change the stroke between the vehicle body and each wheel by supplying and discharging fluid, and detects the stroke between the vehicle body and the wheels at each wheel position. a vehicle height detecting means; an average vehicle height calculating means for averaging the detected values of the vehicle height detecting means within a changeable calculation time; and when the calculated value of the average vehicle height calculating means is outside the target vehicle height range. and actuator control means for controlling the actuator,
A stop/running determining means for determining whether the vehicle is stopped or running, and when the stopping/running determining means determines that the vehicle is stopped, the calculation time is changed to a short value that allows sensing changes in vehicle height due to changes in load. and a running calculation time changing means for changing the calculation time to a value longer than when the vehicle is stopped when the stop/running determining means determines that the vehicle is running.

[Effect]

When the vehicle is determined to be at a stop by the stop/running determining means, the vehicle stop calculation time changing means changes the calculation time for calculating the average vehicle height to a short predetermined value, and when it is determined that the vehicle is traveling, The running calculation time changing means changes the calculation time to a longer predetermined value. As a result, when the vehicle height changes due to passengers getting on and off or loading and unloading luggage when the vehicle is stopped, the stroke detected by the vehicle height detection means is averaged in a short calculation time by the average vehicle height calculation means, so that the calculated average The vehicle height value quickly reflects such changes in vehicle height, and the control sensitivity when the vehicle is stopped increases. On the other hand, even if rolls, dives, scuts, etc. occur during driving, they are averaged over a long calculation time by the average vehicle height calculation means, so the average vehicle height value is calculated including rollback, and is almost smooth. This causes the control sensitivity to become dull when driving. Therefore, when the vehicle is stopped, vehicle height control quickly responds to changes in load, and while the vehicle is running, it barely responds to changes in attitude, and unnecessary vehicle height adjustments are not made.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on FIGS. 2 to 4. This embodiment is applied to a one-box car equipped with a full hydropneumatic suspension that does not have an auxiliary spring such as a metal spring and receives the load by the force generated by a fluid pressure cylinder.

In Figure 2, 2FL to 2RR are the front left to rear right wheels,
Reference numeral 4 indicates a wheel side member, 6 indicates a vehicle body side member, and 8 indicates a control type suspension as a vehicle height adjustment device.

This controlled suspension 8 includes a hydraulic pump 10 and an oil tank 12, which serve as a hydraulic power source as a fluid pressure source, and an accumulator 14, which is disposed on the load side of the hydraulic power source. Check valve 16. Hydraulic source side oil passage opening/closing part 18 and front wheel side and rear wheel side oil passage opening/closing parts 20F.

2OR, suspension characteristic variable parts 22FL to 22RR installed for each wheel 2FL to 2RR, hydraulic cylinders 24FL to 24RR as actuators, vehicle height sensors 26FL to 26RR for vehicle height detection, and pressure sensors for pressure detection. 2F FL to 2F RR, acceleration sensor 28, vehicle speed sensor 29. The controller 30 is also provided.

Of these, the hydraulic pump 10 is configured as a tandem type pump that rotates using the vehicle engine as a driving source and discharges hydraulic pressure to the power steering device and the hydraulic suspension 8. The suction side of this hydraulic pump 10 is connected to the oil tank 12 by a pipe 31, and the discharge side thereof is connected to a pipe 32. The load side of this piping 32 is communicated with an accumulator 14 for absorbing pulsation, and is also connected via a check valve 16 to an oil passage opening/closing section 18 on the oil pressure source side.

This oil passage opening/closing part 18 is an electromagnetically operated two-boat switching valve 3.
4, a relief valve 36 with a predetermined relief pressure, and a divider 38 that distributes the oil passage between the front and rear wheels. It communicates with the relief valve 36 and the hydraulic source side ports of the flow divider 38.

The switching valve 34 has a normally open structure that takes a communicating position when the control signal S1 supplied to the electromagnetic solenoid is off, and takes a blocking position when the control signal S1 is on.

Tank-side boats of the switching valve 34 and the IJ-F valve 36 are connected to the oil tank 12 by a pipe 40. A filter 42 of a filtration layer is inserted in the middle of the pipe 40. The two boats on the load side of the flow divider 38 are provided with piping 32F.

32R are connected to each other, and these pipes 32F and 32R are connected to the front wheel side and rear wheel side oil passage opening/closing parts 20F and 2OR, respectively.

The front wheel side oil passage opening/closing section 20F is equipped with a flow divider 42F whose input port is connected to the piping 32F at a position on the oil pressure source side, and flow restriction type check valves 44PL and 44FR1 electromagnetically operated type are installed on the load side of the flow divider 42F. 2 boat switching valve 46
It is equipped with FL, 46FR, 48F (communication valves), and relief valves 50PL and 50FR. To explain this in detail, the two load-side boats of the flow divider 42F are connected to one ends of the pipes 32FL and 32FR corresponding to the front left and front right wheel sides, respectively. Among these, the other end of the front left wheel side piping 32FL communicates with one boat of another switching valve 48F and the high pressure side boat of the relief valve 50FL via a check valve 44FL and a switching valve 46FL. This leads to the suspension characteristic variable section 22PL on the side. Front right wheel side piping 32
Similarly, the other end of FR is connected to the check valve 44FR and the switching valve 46FR.
It communicates with the other boat of another switching valve 48F and the high pressure side boat of the relief valve 50FH, and also reaches the front left wheel side suspension characteristic variable section 22PR.

The switching valves 46FL and 46BPR inserted in series in each of the pipes 32FL and 32FR take the cutoff position based on the built-in check valve when the control signal S2 supplied to the electromagnetic solenoid is off, and the control signal S2 It has a normally closed structure that assumes a communicating position when the is on. Also,
A switching valve 48 inserted between the pipes 32FL and 32FR
F also has a normally closed structure in which it assumes a shutoff position by a built-in check valve when the control signal S3 supplied to the electromagnetic solenoid is off, and assumes a communicating position when the control signal S3 is on.

Furthermore, the rear wheel side oil passage opening/closing part 2OR also includes a flow divider 42R2 that divides hydraulic oil to the rear left and rear right wheels, flow restriction type check valves 44RL, 44RR, and electromagnetically operated two-boat switching valves 46RL, 46RR, 48R ( communication valve) and relief valves 50RL and 50RR, and piping 32RL and 32
It is connected identically to the front wheel side via RR. here,
Each of the relief valves 50FL to 50RR is set at a predetermined relief pressure higher than the normal pressure range in order to prevent an abnormal pressure rise on the load side, and the low pressure side boat is connected to the tank 12 by a pipe 52. ing.

Each of the suspension characteristic variable parts 22FL to 22RR includes a free piston-type first and second accumulator 54, 56 as a gas spring, a two-boat electromagnetic switching valve 58 for varying a spring constant, and a variable accumulator for generating a damping force. It is equipped with an aperture 60. The first accumulator 54 is directly connected to the pipe 32FL, and the second accumulator 54 is directly connected to the pipe 32FL.
6 is connected via a switching valve 58, and the piping 32
A variable aperture 60FL is inserted in series with FL. The switching valve 58 is opened using the motor 58A as an actuator.

The closed position is switched, and the motor 58A is rotated by the drive signal S4. The variable throttle 60 is also energized by the rotation of the motor 60A to adjust whether the flow path is wide or narrow, and a drive signal S5 is supplied to the motor 60A.

Furthermore, each of the hydraulic cylinders 24FL to 24RR has a second
As shown in the figure, it is constructed as a single-acting type, and only a pressure chamber separated by a piston 24b is formed in its cylinder tube 24a. Piping 32FL (~3
2RR) is connected.

And in the front wheel side hydraulic cylinders 24FL and 24PR,
The cylinder tube 24a is attached to the wheel side member 4, the end of the piston rod 24c is attached to the vehicle body side member 6, and on the contrary, the rear wheel side hydraulic cylinders 24RL, 2
In the 4RR, the cylinder tube 24a is attached to the vehicle body side member 6, and the end of the piston rod 24c is attached to the wheel side member 4.

In addition, in FIG. 2, vehicle height sensors 26FL to 26RR
is composed of a potentiometer, etc., and generates a vehicle height signal HF L ”H with a voltage value corresponding to the relative distance (stroke).
RR is output to the controller 30. Pressure sensor 27F
L~27RR are front wheel side and rear wheel side oil passage opening/closing parts 20F, 2
In the OR, each of the pipes 32FL to 32RR is connected to the load side position, and the pressure at the connection position is transferred to the hydraulic cylinder 24FL.
It is detected as an internal pressure of ~24RR, and a pressure signal P PL'' P RR having a voltage value corresponding to that pressure is output to the controller 30.

Further, the acceleration sensor 28 is installed at a predetermined position on the vehicle body,
A signal G corresponding to the acceleration in the lateral (vehicle width) direction and longitudinal direction acting on the vehicle body is output to the controller 30. The vehicle speed sensor 29 detects, for example, the rotational speed of the output shaft of the transmission, and outputs a signal (2) corresponding to the vehicle speed to the controller 30.

As shown in FIG. 3, the controller 30 inputs a vehicle height detection signal HFL%H+tR and a pressure detection signal PFL~P.
A gain adjuster 70 that multiplies the RR and acceleration detection signal G by the gain, an A/D converter 72 that digitizes the output of the gain adjuster 70, an interface circuit 74 that inputs the input vehicle speed detection signal V, /D converter 72
and a microcomputer (CP, U) 7 that takes in the output signal of the interface circuit 74 and performs predetermined processing.
6, and a drive circuit 78 that drives each solenoid and motor according to a control signal output from the computer 76. Further, the controller 30 includes a mechanism for keeping the power on for a predetermined period of time even after the ignition switch is turned off.

The microcomputer 76 inputs a vehicle speed signal V, an acceleration signal G, and a vehicle height signal HF L ''=H* * +
and the pressure signal P PL””-P ILR, and the fourth
As shown in the figure, the vehicle height is controlled according to the driving condition, and the spring constant is adjusted accordingly.

The damping force is also controlled based on a program not shown.

Next, the operation of this embodiment will be explained.

First, flowchart 1 in FIG. 4, which is executed by the controller 30, will be explained. The process shown in FIG. 4 is continued from the time the power is turned on and started until the power is turned off.

In step (3) in FIG. 4, the microcomputer 76 of the controller 30 reads the detection signal V of the vehicle speed sensor 29 via the interface circuit 74, and temporarily stores the value as a vehicle speed value.

Next, the process moves to step ■, where the preset vehicle speed ■ determines that the vehicle is almost stopped. (for example, 5 km/h),
It is determined whether the vehicle speed is the vehicle speed V obtained in step (2) or whether V≧Vo.

If the determination in step (2) is YES, it is assumed that the vehicle is traveling, and the process moves to step (2), where the calculation time T for calculating the average vehicle height value, which will be described later, is set to T=T.

Set to . The value of this calculation time T is set to a long predetermined time in consideration of preventing malfunctions due to changes in behavior such as roll, dive, and scut during running. On the other hand, if the determination in step (2) is No, the vehicle is at a stop or is in a very similar driving state (hereinafter referred to as "stopped"), so the process in step (2) is performed. In step ■, calculation time T=T.

is set to The value of this calculation time T is set to a short predetermined value (<T,) that increases the sensitivity of vehicle height adjustment while the vehicle is stopped and can quickly respond to changes in load.

After completing steps ■ and ■ above, step
Proceed to process ①. The processing of steps (■) to (■) is performed for each of the four wheels, and in step (2), the microcomputer 76 uses the vehicle height sensors 28FL to 26RR of each wheel.
The detection signal H (: HFL to HRR) is read and the value is stored as a vehicle height value (instantaneous value). In step (2), the following integral calculation is performed to calculate the vehicle height average value HA for each wheel. That is, the integral range of this definite integral is from a certain time t to t+
up to T, and varies depending on the upper limit T or the processing in step (2) or (2). Next, step■, then step■,■
It is determined whether or not the processing has been completed for the four wheels. If NO, those processes are repeated. If YES, the process moves to step ■. Since the start of the average value calculation in step ■, the specified It is determined whether or not time T has elapsed.

In this step ■, if the judgment is NO, step ■～
The process of step (2) is repeated, and if the determination is YES, the process proceeds to step (2) and subsequent steps.

In step (2), the microcomputer 76 calculates the vehicle height deviation IHA-H,l for each wheel using the average value HA obtained in step (2). Here, H8 is the target vehicle height value.

Further, the process proceeds to step [phase], and it is determined whether or not 1HA-H,l≧ΔH for at least one wheel among the vehicle height deviations IHA-H,l for the four wheels determined in step (2). Here, ΔH is an allowable deviation from the target vehicle height value Hs, and Hs±ΔH forms the target vehicle height range. If the judgment in this step [phase] is YES, the vehicle height value for at least one wheel deviates from the target vehicle height range, and it is assumed that it is necessary to perform vehicle height adjustment, so perform the vehicle height adjustment process in step Return to step (2). On the other hand, if the determination is No, return to step (2).

In step (3), the microcomputer 76 performs processing for raising or lowering the vehicle height, for example, in Japanese Patent Laid-Open No. 63-15
This is done using the method shown in No. 4413 (so-called 3-axle vehicle height control). At this time, when increasing the vehicle height, the control signal S
1, one of the previous and subsequent control signals S3 is turned on, and each control signal S2 is turned on. This results in
The communication valve 48F when the unload valve 34 is in the closed state 2 or before or after
(48R) is open, each switching valve 46FL (~46RR)
is in an open state, and the hydraulic oil discharged from the pump 10 flows into each hydraulic cylinder 24FL to 24RR, raising the vehicle height. On the other hand, when lowering the vehicle height, the control signal S1 is turned off, one of the front and rear control signals S is turned on, and each control signal S is turned on. As a result, the unloading valve 34 is in the open state 2 or the communication valve 48 is in the open state 2.
F (48R) is open, each switching valve 46FL (~46RR)
) is opened, and the hydraulic oil in the hydraulic cylinders 24FL to 24RR flows out into the tank 12, lowering the vehicle height. Here, a communication command to either the front or rear communication valve 48F (48R) is issued depending on whether the vehicle is running at a high speed or at a constant speed, for example, based on the magnitude of the vehicle speed value V. Further, the controller 30
Detected values P6 of pressure sensors 27FL to 27RR. ．． ~ Po
The average cylinder pressure is calculated based on the cylinder pressure, the load is estimated from this cylinder pressure, and the target vehicle height range is raised or lowered depending on the magnitude of the estimated value.

Here, the vehicle height sensors 26FL to 26RR and the processing in steps ①, ②, and ① in Fig. 4 constitute a vehicle height detection means, the processing in steps ② to ③ in Fig. 4 constitute an average vehicle height calculation means, and Steps ■ to ■ in Figure 4 and drive circuit 78. Switching valve 34.4
6FL to 46RR and communication valves 48F and 48R constitute actuator control means. In addition, the vehicle speed sensor 29 and the processing in steps (2) and (2) in FIG. 4 constitute a stop/running determination means, and the processing in step (4) in FIG. It also corresponds to means for changing the calculation time when the vehicle is stopped.

In this embodiment, since the above-mentioned process is repeated, the time required to calculate the average vehicle height when the vehicle is stopped is shortened, and the control sensitivity is increased. Therefore, when the load changes due to passengers getting on and off the vehicle or loading and unloading luggage, the vehicle height value also changes accordingly, but the average vehicle height value after the change is calculated in a short time. If this average vehicle height value or even one wheel deviates from the target vehicle height range, a three-axis vehicle height adjustment with improved static stability of force is performed to bring the vehicle height value within the target range. In other words, the responsiveness of vehicle height adjustment when the vehicle is stopped is maintained well.

On the other hand, when the vehicle is running, the average vehicle height calculation time is changed to a longer value and the control sensitivity is lowered.

For this reason, if roll, nose dive, or scut occurs due to turning, acceleration and deceleration while driving, the vehicle height value at each wheel position will also change, but such attitude changes are usually accompanied by shaking back. By lengthening the calculation time of the average vehicle height value, most of the series of vehicle height changes are averaged for each wheel.

As a result, the calculated average vehicle height value is almost the same as the original vehicle height value, that is, the value within the target vehicle height range, and no vehicle height adjustment is performed.In other words, the roll that occurs when turning or accelerating/decelerating , dive, and scut are almost never misunderstood as changes in vehicle height.

Similarly, when passengers and luggage move inside the vehicle while the vehicle is running, the average vehicle height value is calculated for each wheel through long-term averaging calculations. Therefore, even if such movement occurs, if the original load and the load after movement are balanced within the calculation time (for example, if the left and right people are placed in the wrong place in the rear seats), the calculated vehicle height average value remains almost unchanged from its original value, and no vehicle height adjustment is performed. However, if the person in the front passenger seat moves to the rear seat, for example, the average value of the vehicle heights on the front left side and the rear left side may deviate from the target vehicle height range, and in such a case, Vehicle height is adjusted as necessary to maintain a constant vehicle height.

In this way, while driving, the responsiveness of the vehicle height adjustment is actively lowered, and unnecessary vehicle height adjustments are not made, so there is no unnecessary discomfort for the occupants, and the hydraulic cylinder,
Deterioration in the durability of the switching valve is also prevented. On the other hand, for example, an existing vehicle speed sensor can be used in conjunction with the configuration to determine whether the vehicle is stopped or running.
This has the advantage that the configuration is simplified, and the processing program is also simplified because it is only necessary to change the calculation time for averaging, which is one element of control sensitivity, depending on the determination.

By the way, in this embodiment, when the ignition switch is in the on state, the controller 30 inputs the detection signal G of the acceleration sensor 28 based on a predetermined program, and when a predetermined roll condition, acceleration, or deceleration condition is satisfied, , the electromagnetic switching valve 58 and the variable throttle 60 are controlled in the direction of increasing the gas spring constant and increasing the damping force, thereby suppressing posture changes during driving.

Furthermore, when these conditions are not met, control is performed to reduce the gas splash constant and damping force to reduce vibration transmission from the road surface.

Note that the vehicle height detection means of the present invention is not limited to the structure in which a vehicle height sensor is provided in each wheel as described above;
For example, a vehicle height sensor may be provided for each of three arbitrary wheels, and the vehicle height value of the remaining one wheel may be determined by calculation.

Furthermore, the vehicle height adjustment device according to the present invention is not limited to one that performs three-axis vehicle height control as described above (for example, the communication valves 48F and 48R are omitted, and the vehicle height adjustment device is configured to perform four-axis control independently for each wheel. It can also be applied to

Furthermore, the working fluid in the present invention is not necessarily limited to the working oil as described above, and a gas such as air may also be used. Further, the actuator applied to the present invention may have an air chamber formed of an elastic body at each wheel position as described in, for example, Japanese Patent Laid-Open No. 63-154413, and may be configured to supply and discharge air from the air chamber. On the other hand, the controller is not necessarily limited to one using a microcomputer, and may be configured using analog electronic circuits such as comparators and integrators.

〔Effect of the invention〕

As explained above, the present invention determines whether the vehicle is stopped or running, changes the calculation time for calculating the average vehicle height to a predetermined short value when the vehicle is stopped, and changes the calculation time to a predetermined short value when the vehicle is running, which is longer than when the vehicle is stopped. Since the control definition is changed to the value when the vehicle is stopped and when the vehicle is running, it can be switched by simple processing and configuration.As a result, while the configuration and processing are simple, changes in vehicle height due to changes in vehicle load can be quickly detected when the vehicle is stopped. The responsiveness of high adjustments is maintained well, and when driving, it is possible to accurately eliminate malfunctions such as mistaking posture changes such as rolls and dives as changes in vehicle height, which can cause unnecessary anxiety to passengers. Moreover, it is possible to prevent a decrease in the durability of the actuator and the like due to unnecessary vehicle height adjustment.

[Brief explanation of the drawing]

FIG. 1 is a claim correspondence diagram, FIGS. 2 to 4 are diagrams showing one embodiment of the present invention, FIG. 2 is a block diagram showing the overall configuration, FIG. 3 is a block diagram of the controller, and FIG. 4
The figure is a schematic flowchart showing an example of a processing procedure regarding vehicle height adjustment by the controller. In the figure, 4... wheel side member, 6... vehicle body side member, 8...
・・Controlled suspension, 24FL~24RR...
Hydraulic cylinder, 26FL~26RR...Vehicle height sensor,
29...Vehicle speed sensor, 30-...Controller, 34
．． 46FL ~ 46RR...Switching valve, 48F, 48R・
...Communication valve, 76...Microcomputer.

Claims (1)

[Claims] (1) an actuator that can change the stroke between the vehicle body and each wheel by supplying and discharging fluid; and a vehicle height detection means that detects the stroke between the vehicle body and the wheels at each wheel position;
average vehicle height calculation means for averaging the detection values of the vehicle height detection means within a changeable calculation time; and control of the actuator when the calculation value of the average vehicle height calculation means is outside the target vehicle height range. stop/running determination means for determining whether the vehicle is stopped or running;
When the stop/running determination means determines that the vehicle is stopped, a stop calculation time changing means changes the calculation time to a short value that allows the vehicle height change due to a load change to be detected; When it is determined that the vehicle is running, the calculation time is
1. A vehicle height adjustment device comprising: means for changing a calculation time during driving to a value longer than when the vehicle is stopped.