JPS6296126A - Ground clearance adjuster for automobile - Google Patents

Abstract

PURPOSE:To prevent the ground clearance adjustment from being improperly made by providing a means which detects an abnormal condition in a ground clearance adjustment control by a ground clearance control means, thereby suspending the ground clearance adjustment control based on a signal from the above said abnormal condition detecting means. CONSTITUTION:This device is provided with an abnormal condition detecting means 106, by which a judgement is made upon receiving of output signals from a ground clearance control means 105 and a ground clearance sensor 102 as to whether a ground clearance adjustment control by the ground clearance control means is in order or not. An actuating signal is outputted to solenoid valves 18b, 37b and 44b of levelling valves and solenoid valves 71b and 72b of anti-rolling valves so as to suspend the ground clearance adjustment control as an abnormal condition is detected by the abnormal detecting means 106. This constitution can prevent the running performance from being impaired by an improper ground clearance adjustment which will be made when the abnormal condition happens to a height adjuster.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vehicle height adjustment device for an automobile, which is disposed between an axle and a vehicle body and variably controls the vehicle height relative to the axle.

(Prior Art) The body of an automobile is supported by axles (wheels) via a suspension device, and this suspension device
The vehicle includes a spring unit that softens wheel vibrations during driving and transmits the vibrations to the vehicle body, and a damper unit that dampens the vibrations caused by the spring units.

Make it into the cylinder of this damper unit! Various vehicle height adjustment devices have been proposed in the past that adjust the vehicle height by supplying and discharging lI fluid. - To give an example, there is a vehicle height adjustment device disclosed in Japanese Patent Application Laid-Open No. 56-82616, which lowers the vehicle height when the vehicle speed exceeds a predetermined value, and lowers the vehicle height when the vehicle speed exceeds a predetermined value. The objective is to improve running stability during high-speed driving, prevent belly-rubbing during low-speed driving on rough roads, and improve ride comfort by increasing the speed of the vehicle.

Vehicle height adjustment control in such devices is performed by electrically controlling the operation of pumps and valves for supplying working fluid, but if an abnormality occurs in this control system or device, the control will not continue as it is. It is not advisable to continue. This abnormality occurs when the vehicle height cannot be raised even by supplying working fluid from the pump because the vehicle weight is too large. When discharging electricity separately, when control wiring and connectors become disconnected, disconnected, short-circuited, etc., when sensors malfunction, etc. There is a problem in that even if the vehicle height is adjusted, the vehicle height cannot be adjusted correctly, and as a result, the running performance, stability, etc. of the vehicle may be impaired.

For this reason, for example, JP-A-58-49506
The issue discloses a device that detects an abnormality in a vehicle height adjustment device and, when an abnormality is detected, displays the occurrence of the abnormality so that the driver can take prompt action.

(Object of the Invention) In view of problems caused by an abnormality in a vehicle height adjustment device, the present invention provides an automobile that can stop vehicle height adjustment when an abnormality is detected, and prevent vehicle height adjustment control from being performed even if the abnormality remains. The purpose of this invention is to provide a vehicle height adjustment device.

(Structure of the Invention) The vehicle height adjustment device of the present invention includes a vehicle height adjustment device that can adjust the vehicle height by supplying and discharging a working fluid between the vehicle body and the axle. The vehicle height can be variably controlled by controlling exhaust, and when the vehicle height control means performs variable control of the vehicle height, the abnormality detection means detects whether or not there is an abnormality in the variable control. In addition, the present invention is characterized in that when an abnormality is detected, the variable control of the vehicle height is stopped by the control stop means.

(Embodiments) Hereinafter, preferred embodiments of the vehicle height adjustment device of the present invention will be described with reference to the drawings.

The vehicle height adjustment device of the Kino 1M example uses hydraulic oil as the hydraulic fluid, and as shown in FIG. Become.

First, the cylinder unit 2 is disposed between a vehicle body 4 and a width shaft 6 attached to a wheel 5, and a cylinder 7
, a piston 8 that is fitted into the piston 8 so as to be able to move forward and backward, and a piston rod 9 that is connected to the piston 8, the lower end of the cylinder 7 is attached to the bearing casing 6a of the axle 6, and the upper end of the piston rod 9 is attached to the vehicle body 4 via a bracket 4a.

The piston rod 9 is penetrated in its axial direction and has a diameter nIj.
A passage (not shown) is formed, and a piping connection part 10 is provided at the upper end thereof, and connects a cylinder liquid chamber 11 surrounded by the cylinder 7 and piston 8 to the hydraulic pressure adjustment means 3.

Next, the hydraulic pressure adjustment means 3 will be explained.

Main path 1 to which oil tank 12 and hydraulic pump 13 are connected
4, intermediate passages 16 and 17 are branched via a dividing valve 15. The diverting valve 15 is provided with a function of equally diverting the hydraulic oil to the intermediate passages 16 and 17 even if the pressure or load fluctuates. Note that this main road 14 has a branch road 14a,
It communicates with the oil tank 12 via the unload valve 72, and when the oil does not need to be supplied to the branch valve 15 side, the oil is returned to the oil tank 12 through the branch 114a of the oil discharged from the hydraulic pump 13.

A leveling valve 18 is connected to the intermediate passage 16, and communication passages 20 and 21 are branched off via a dividing valve 19.

The leveling valve 18 is a two-bottom, two-position type switching solenoid valve, and includes a spring 18a and a solenoid 18b, and is normally in a lower position to block the intermediate passage 16. The flow dividing valve 19 is constructed in the same manner as the flow dividing valve 15 described above.

The communication passage 20 is connected to the cylinder liquid chamber 11 of the right front wheel portion via a flow rate control valve 22 that adjusts the flow rate to the hydraulic pressure source side, and is connected to an air spring 23 in the middle thereof.

Although not shown, the air spring 23 is divided into an air chamber and a liquid chamber by a diaphragm, and the liquid chamber is connected to the communication path 20. A pair of check valves 26.
A damping force generating valve 80 consisting of 27 is provided.

Communication path 2 between the air spring 23 and the cylinder liquid chamber 11
A detour passage 25 that detours around the check valves 26 and 27 is formed in the detour passage 25, and the detour passage 25 includes a pilot-type two-port throttle switching valve 24a.

24b are connected in series. The damping force control valve 24 is controlled by the damping force generating valve 80 by making the passage area of the bypass passage 25 variable.
The damping force is variably controlled as a result of adjusting the liquid environment passing through the damping force.

The throttle switching valve 24a is normally located at the left side position and is connected to the communication path 2.
0 is gently throttled, and when pilot pressure is applied, the communication path 20 is shut off at the right position. Further, the throttle switching valve 24b normally throttles the communication passage 20 gently at the left position, and tightly throttles the communication passage 20 at the right position when pilot pressure is applied. Therefore, the cylinder liquid chamber 11 due to the air spring 23
The pressure buffering effect within is maximum in the soft state when the damping force control valve 24 is operated and both the throttle switching valves 24a and 24b are placed in the left position, followed by the hard state in which only the throttle switching valve 24b is placed in the right position. , Throttle switching valve:: 4
It is lowest in the very hard state with a on the right side.

The communication passage 21 is connected to a damping force generating valve 81 consisting of a flow rate control valve 28, an air spring 29, and a pair of check valves 32 and 33, and is also connected to the damping force generating valve 81 via a detour passage 31.
Damping force control valves 30 (throttle switching valves 30a, 30b
) is connected to communicate with the cylinder fluid chamber provided in the left front wheel. Note that the configurations of these valves and air springs are the same as those in communication 't820.

Further, the communication passages 20J and 21 are communicated with each other by a communication passage 70, and an anti-roll valve 71 is disposed in the communication passage 70. The anti-roll valve 71 is a 2-point, 2-point type switching solenoid valve that is normally pressed by a spring 71a to close this communication passage 70, and when adjusting the vehicle height, the solenoid 71 is pressed.
When the vehicle height is adjusted, the oil pressures in the communication passages 20 and 21 are made equal, and the oil pressures in the cylinder liquid chambers provided at the left and right front wheels are made equal. The communication passage is closed, so the anti-roll valve 71 remains closed even when the vehicle is turning (rolling), preventing the heavy body from tilting excessively due to turning, thereby improving driving stability. It is designed to increase the

The intermediate passage 17 is branched into a communication passage 35 and a communication passage 36 via a diversion valve 34.

The communication path 35 includes a leveling valve 37 (including a spring 37a and a solenoid 37b), a flow control valve 38, and an air spring 39.
, a damping force generating valve 82 consisting of a pair of check valves 42 and 43 is connected, and a damping force control valve/IO (throttle switching valve 40a) is connected in parallel with the damping force generating valve 82 via a bypass passage 41.
, 40b) are connected to communicate with the cylinder liquid chamber provided in the right rear wheel section.The communication passage 36 is connected to a leveling valve 44 (with a spring 44a and a solenoid 44b), a flow control valve 45, and an air flow control valve 45. A damping force generating valve 83 consisting of a spring 46 and a pair of check valves 49 and 50 is connected, and a damping force control valve I valve 47 (throttle switching valve 47 a , 47b) are connected,
It communicates with the cylinder liquid chamber provided in the left rear wheel. In addition,
The configuration of these valves and air springs is the same as that provided in the intermediate passage 16 and the communication passage 20, 21.

With the above configuration, the vehicle height of the left and right front wheels can be adjusted by the leveling valve 18, the vehicle height of the right rear wheel can be adjusted by the leveling valve 37, and the vehicle height of the left rear wheel can be adjusted by the leveling valve J3 and the leveling valve 44.

Furthermore, if the vehicle height is adjusted independently on the four wheel levers, depending on the unevenness of the ground, the vehicle body will be supported by three wheels and the remaining wheel will be floating, making it difficult to adjust the vehicle height correctly. However, by adjusting the vehicle height of the four wheels using the three leveling valves in this way, the left and right front wheels will be adjusted so that the average vehicle height is the target vehicle height, and the vehicle body will be supported at three points. Since the vehicle height is adjusted, you can adjust the vehicle height correctly.

51 is the liquid chamber of the air spring 23 and the throttle switching valve 24a.

30a, 40a, and 47a, and a drain passage 53 is connected via a pilot valve 52 on the way.
is branched.

The pilot valve 52 is a 3-point/3-position type switching solenoid valve, and has springs 52a, 52b and a solenoid 5 at both ends.
2c and 52d, normally block the pilot passage 51 at the neutral position, communicate the passage 51 at the upper position, and connect the damping force control valve side of the passage 51 at the lower IQ position. It is configured to be connected to the drain passage 53.

54 is a liquid chamber of the air spring 29 and a throttle switching valve 24b.

30b, 40b, and 47b, and is connected to the drain passage 53 via a pilot valve 55 on the way.
is branched. The pilot valve 55 (spring 55a,
55b and solenoid 55C955d) are constructed similarly to the pilot valve 52 described above.

Note that the solenoid 18b of the leveling valve.

The supply of electricity to 37b and 44b is controlled by vehicle height control means (described later) that includes a vehicle height sensor and the like.

The pilot valve solenoids 52c and 52cj.

55c, 55d is controlled by automatic or manual damping force control means, and the damping force control valves 24, 30, 4
0.47 is activated to select a predetermined damping characteristic.

Next, the control system by the vehicle height control means will be explained with reference to the block diagram of FIG.

The vehicle height control means 105 includes a vehicle height selection switch 101, a vehicle height sensor 102, a vehicle speed sensor 103, and a steering angle sensor 10.
A signal from 4 is input. The vehicle height selection switch 101 is configured so that either the 'AUT O' button or the =Hi'l button is selected, and a signal based on this selection and the vehicle height, vehicle speed and steering angle sensor 102 are transmitted.
．． When the vehicle height, vehicle speed, and steering angle signals of each wheel are input from 103 and 104, the vehicle height control means 105 controls each leveling valve 18, 37.4 of the vehicle height adjustment device 3 shown in FIG.
4 to each solenoid F nearer 8b, 37.
b, 44b, and further adjusts the vehicle height, and when the vehicle height adjustment is not required without J3, an activation signal is sent to open the unload valve 72, and when the vehicle is in a roll (turning) state, an activation signal is sent to the solenoid of the anti-roll valve 71. Communication path 7o to 71b
Sends an activation signal to close the Detection of whether or not the vehicle is in the roll state is performed by detecting whether the vehicle is in the roll region shown in FIG. 3 from the relationship between the vehicle speed and the steering angle detected by the vehicle speed sensor 102 and the steering angle sensor 104. Table 1 shows an example of vehicle height adjustment based on the relationship between the selection of the selection switch 101 and the driving condition (vehicle speed).

In addition, in Table 1, when driving at high speed in the 'AUTO' state, the front wheels are set to LOW and the rear wheels are set to NORM.
It may be set to AL to increase running stability.

Further, this device receives an output signal from the vehicle height control means 105 and an output signal from the vehicle height sensor 102, and detects whether there is any abnormality in the variable control of the vehicle height by the vehicle height control means 105. Abnormality detection means 106 is provided, and when an abnormality in the variable vehicle height control is detected by this abnormality detection means 106, the solenoids 18b, 37b, 44b of each leveling valve 18, 37.44 are activated from the abnormality detector m106.
, an activation signal is output to the solenoid 71bll13 of the anti-roll valve 71 and the solenoid 72b of the unload valve 72 to stop the vehicle height adjustment control.

The control contents of such vehicle height control means 105 will be explained with reference to the flowchart shown in FIG.

This control starting from step S1 detects the mode of the vehicle height selection switch in step S2, and detects the mode of the vehicle height selection switch in step S2.
In the UT○'' mode, the process proceeds to step S3, where it is determined whether the vehicle speed is greater than a predetermined value α (for example, 60&/H). When the vehicle speed is less than the predetermined value α, the process proceeds to step S4, where “N” is set as the target vehicle height. ○RMAL'' position is set, and when the vehicle speed is equal to or higher than the predetermined value α, the process advances to step S5 and the target vehicle height is set to the ``L○W°'' position.On the other hand, when the vehicle height selection switch mode is set to ``Hi'' If so, it is determined in step S6 whether the vehicle speed is greater than the target value α, and if the vehicle speed is greater than α, the process proceeds to step $7 and the target vehicle height is set as ''.
NORMAL" position is set, and if the vehicle speed is smaller than α, proceed to step S8 and set the target vehicle height" l-110
The H"' position is set. Next, in step S9, the target vehicle height and the actual vehicle height are compared, and a control signal is outputted to set the vehicle height to the target vehicle height (step 510).
.

The above operation completes this flow, and this flow is repeated thereafter.

Next, the abnormality detection means 10 according to the flowchart of FIG.
6 will be explained below.

This flow starts from step S20, and step S21
Detects whether a signal to raise the vehicle height is being output, that is, whether the vehicle height is being adjusted to be higher. If this signal is being output, the process proceeds to step 823, where the signal from the vehicle height sensor is detected. Based on the signal, it is detected whether the actual vehicle height has increased. If the vehicle height has actually increased, it means that there is no abnormality in the vehicle height adjustment operation, and the flow proceeds to step S27 to end this flow. However, if the vehicle height has not increased, it means that there is no abnormality in the vehicle height adjustment operation. This means that there is, so step S25. Proceeding to S26, a signal is output to open the unload valve 72 and close the leveling valve 18°37.44, thereby canceling the vehicle height adjustment.

On the other hand, if the vehicle height increase signal is not output, it is detected in step 822 whether or not a vehicle height decrease signal is output. If this signal is also not output, the vehicle height has not been adjusted, so step 822 is performed. Proceed to S27 and end this flow. When the vehicle height lowering signal is output,
In step 824, it is detected whether or not the actual vehicle height has decreased. If the actual vehicle height has decreased, it is normal, so the process proceeds to step S27 and ends this flow. If the actual vehicle height is not lowered, there is some abnormality, and the process proceeds to steps 825 and 826, where the vehicle height adjustment is canceled in the same manner as described above.

With the above steps, this flow is completed, and thereafter this flow is repeated to continue detecting the presence or absence of an abnormality.

Note that the embodiments of the present invention are not limited to the above-mentioned scope.
For example, the cylinder unit may be upside down from that of the above embodiment, and the upper end of the cylinder may be attached to the vehicle body, and the lower end of the piston rod may be supported.

Further, regarding the oil pressure adjustment means, the leveling valve and the cylinder liquid chamber may be directly connected, instead of via the damping force generating valve and the damping force control valve as in the above embodiment.

(Effects of the Invention) As explained above, according to the present invention, the vehicle height can be adjusted by controlling the supply and discharge of working fluid to the vehicle height adjustment means disposed between the vehicle body and the axle. In addition, as soon as an abnormality in the vehicle height adjustment is detected, the vehicle height adjustment is stopped, so even if an abnormality occurs in the vehicle height adjustment device, the vehicle height will not be adjusted incorrectly. This can prevent the drivability and running performance of the vehicle from being impaired.

[Brief explanation of drawings]

Figure 1 is a hydraulic circuit diagram of the vehicle height adjustment device of the present invention, Figure 2 is a block diagram showing the control means of the vehicle height adjustment device of the present invention, and Figure 3 is a graph used to determine the roll state. FIG. 4 is a flowchart showing the control contents by the vehicle height control means applied to the vehicle height adjustment device of the present invention, and FIG. 5 shows the control contents by the abnormality detection means applied to the vehicle height adjustment device of the present invention. It is a flowchart. 2...Cylinder unit 6...Axle 11...Cylinder liquid chamber 20.21...Communication path 24.30...
・Damping force control valves 26.27, 32.33...Check valve 71...Anti-roll valve 72...Unload valve No. 2 Fig. 3 Fig. 4 UWI Fig. 5

Claims (1)

[Scope of Claims] Vehicle height adjustment means disposed between the vehicle body and the axle to support the vehicle body relative to the axle, and capable of variably controlling the vehicle height relative to the axle by supplying and discharging working fluid from the outside; a vehicle height control means for variably controlling the vehicle height by controlling the supply and discharge of the working fluid to the vehicle height adjustment means; an abnormality detection means for detecting an abnormality in the variable control of the vehicle height by the vehicle height control means; Vehicle height adjusting means for an automobile, comprising control canceling means for stopping variable control of vehicle height by the vehicle height controlling means when an abnormality is detected by the abnormality detecting means.