JPH058166Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides suspension control when the cycle between maximum vehicle height values that are equal to or greater than the threshold selected by the mode selection switch in vertical fluctuations in vehicle height is within a set time. The present invention relates to a vehicle suspension device whose characteristics are switched to a hard state.

[Technical background of the invention and its problems]

2. Description of the Related Art An electronically controlled suspension device has been proposed that improves riding comfort by electronically controlling the damping force of the shock absorber and the spring constant of the air spring in each suspension unit of an automobile. It is desirable to use such an electronically controlled suspension device to automatically set the suspension to a hard state while the vehicle is traveling on a rough road, thereby reducing vertical movement of the vehicle height and improving ride comfort.

[Purpose of invention]

The present invention has been developed in view of the above points, and its purpose is to reduce the period between maximum vehicle height values that are equal to or greater than the threshold selected by the mode selection switch in vertical fluctuations of vehicle height within a set time. An object of the present invention is to provide a suspension device for a vehicle in which suspension characteristics are switched to a hard state.

[Summary of the idea]

A mode selection switch is provided that can set multiple vehicle height thresholds for determining the pitching state of the vehicle height, and the vehicle height sensor outputs a vehicle height that is higher than or equal to the threshold selected by the mode selection switch during vertical fluctuations in vehicle height. If the cycle between certain maximum vehicle height values is within a set time width, the suspension characteristics are switched to a hard state. In this way, the conditions for switching the suspension characteristics to the hard state can be arbitrarily switched.

[Example of idea]

Embodiments of the present invention will be described in detail below with reference to the drawings.

Fig. 1 shows the entire suspension device according to an embodiment of the present invention, where SFR is a suspension unit for the right front wheel of an automobile, SFL is a suspension unit for the left front wheel, and SRR is a suspension unit for the right rear wheel. Unit, SRL indicates the suspension unit for the left rear wheel. Each of these suspension units SFR, SFL, SRR,
Since each SRL has the same structure,
The structure of only the suspension unit SRL is shown here. The suspension unit SRL is composed of a main air spring chamber 11, a sub air spring chamber 12, a shock absorber 13, and a coil spring (not shown) used as an auxiliary spring. 14 is a pneumatic switching device (actuator) for switching the damping force of the shock absorber 13 between hard and soft. The switching device 14 rotates the control rod 131 around its axis to open the passage 13 formed in the piston 132 of the shock absorber 13.
Open and close 3. This controls the passage area that communicates the two chambers in the shock absorber 13 divided by the piston 132, and switches the damping force of the shock absorber 13 between hard and soft. In addition,
Reference numeral 144 denotes a passage formed in the piston 132, which constantly communicates the two chambers in the shock absorber 13 that are partitioned by the piston 132. 15 is a bellows defining the main air spring chamber. Note that the switching device 14 controls the passage 135 that communicates the main air spring chamber 11 and the sub air spring chamber 12 to communicate or disconnect, thereby switching between hard and soft air springs. In addition, the switching device 1
4 is controlled by a controller 36 equipped with a microcomputer.

Reference numeral 16 denotes an air cleaner, and the atmosphere sent from the air cleaner 16 is sent to the dryer 18 via a solenoid valve 17 for shutting off outside air.
The air dried by this dryer 18 is compressed by a compressor 19 and checked by a check valve 20.
The water is stored in the reserve tank 21 via. This compressor 19 is driven by electric power generated by a generator driven by an engine (not shown). In addition, 191 is a relay for the compressor, and this relay 191 is connected to the controller 36.
controlled by

The reserve tank 21 is connected to each suspension unit via an air supply pipe 23 in which air supply solenoid valves 221 to 224 are installed.
It is connected to the main and auxiliary air spring chambers 11 and 12 of SRL to FL. The main and auxiliary air spring chambers 11 and 12 of the suspension units SRL and RR are interconnected by a communication pipe 25 in which a communication solenoid valve 241 is installed, and the main and auxiliary air spring chambers of the suspension units SFL and SFR are 11 and 12 are connected to each other by a communication pipe 26 in which a communication solenoid valve 242 is interposed. The compressed air in the main and sub air spring chambers 11 and 12 of each suspension unit SRL to SFL is supplied to exhaust pipes 28, check valves 29, dryers 18, and solenoid valves 271 to 274, respectively, which are installed with exhaust solenoid valves 271 to 274, respectively. It is discharged via the valve 17 and the air cleaner 16.

A piping 31 in which a solenoid valve 30 for selecting an air supply side flow path is interposed is arranged in parallel with the above-mentioned air supply piping 23 . Further, the exhaust pipe 28 is provided with a pipe 33 in which an exhaust side flow path selection solenoid valve 32 is interposed.
are installed in parallel. Further, a hard/soft switching solenoid valve 34 is interposed between the air supply pipe 23 and the switching device 14, and the hard/soft switching solenoid valve 34 is controlled to open and close by a signal from a controller 36. Ru.

In addition, solenoid valves 17, 221 to 22
4,271 to 274, 30, and 34 are normally closed valves, and solenoid valves 241 and 242 are normally open valves. Further, the pressure inside the reserve tank 21 is detected by a pressure sensor 35. A detection signal from this pressure sensor 35 is supplied to a controller 36. 37 is the rear wheel suspension unit
This is a pressure sensor that detects the internal pressure of the main and auxiliary air spring chambers 11 and 12 of the SRL and SRR. The detection signal of this pressure sensor 37 is supplied to the controller 36.

38F is a front vehicle height sensor that is installed between the lower arm 39 on the front right side of the automobile suspension and the vehicle body to detect the vehicle height at the front of the automobile, and 38R is a lateral rod 40 on the rear left side of the automobile suspension. This is a rear vehicle height sensor that is installed between the vehicle and the vehicle body and detects the vehicle height at the rear of the vehicle. These vehicle height sensors 38F, 38R
The vehicle height detection signal output from the controller 36
is supplied to Both vehicle height sensors 38F and 38R have Hall IC elements and magnets, one of which is attached to the wheel and the other to the vehicle body, as shown in Figure 3.
It detects nine levels of vehicle height from EH to EL. 41 is a vehicle speed sensor that detects the vehicle speed; 42 is a steering sensor that detects the steering angle of the steering wheel 43; detection signals detected from these sensors 41 and 42 are supplied to the controller 36. 44 is an acceleration sensor that detects acceleration in the longitudinal, lateral, and vertical directions acting on the vehicle body; When the light from the light emitting diode is blocked and does not reach the photodiode, it is detected that there is no acceleration, and when the weight tilts or moves, it is detected that acceleration is acting on the vehicle body. A type of sensor is used.

45 is a vehicle height selection switch that sets the vehicle height to high vehicle height (HIGH), low vehicle height (LOW), or vehicle height adjustment (AUTO), and 46 is a vehicle height selection switch that selects to perform attitude control to reduce vehicle roll. This is an attitude control selection switch. These switches 45, 46
The signal is input to the controller 36. 47 is an oil pressure sensor that detects the oil pressure of lubricating oil for the engine, 48 is a brake sensor that detects the amount of depression of the brake, 49 is an accelerator opening sensor that detects the accelerator opening of the engine, and 50 is the engine rotation speed. Engine speed detection sensor to detect,
51 is an engine switch such as an ignition switch for starting the engine; 52 is a gear position detection sensor that detects the gear position of the transmission; 53
is a mode selection switch for selecting a mode of suspension characteristics. And these switches 4
The output signals of sensors 5, 46, 51 and 53 and the detection signals of these sensors 47, 48, 49, 50 and 52 are supplied to the controller 36. and,
The controller 36 selects the target vehicle height set by the vehicle height selection switch 45, the vehicle height sensor 38F,
The vehicle height is adjusted by comparing the vehicle height detected by 38R and controlling each solenoid valve in a direction in which the vehicle height matches the target vehicle height.

Further, the attitude control function is performed by the controller 36.
This is done by sensing the change in attitude of the vehicle body and its direction with each sensor, and controlling each solenoid valve to offset the change in attitude.

In addition, when performing the above-mentioned vehicle height adjustment, by closing the intake side flow path selection solenoid valve 30 and the exhaust side flow path selection solenoid valve 32,
The vehicle height changes slowly, thereby reducing the discomfort felt by passengers when adjusting the vehicle height. When performing the attitude control described above, by opening the solenoid valve 30 for selecting the air supply side flow path and the solenoid valve 32 for selecting the exhaust side flow path, it is possible to sufficiently cope with sudden changes in attitude.

Next, the operation of an embodiment of the present invention configured as described above will be explained. engine switch 5
When 1 is turned on, the process of the flowchart in FIG. 2 is started. First, as an initial setting, a control signal is output to the switching device 14 to rotate the control rod 131, thereby softening the damping force of the shock absorber 13.
Next, the operation signal of the mode selection switch 53 is read into the controller 36 (step S ₂ ).

By the way, the mode selection switch 53 can be set to one of the first to third modes. When the mode selection switch 53 is set to the first mode (step _S3 ), the vehicle height thresholds are set to NH as the reference vehicle height A and NL as the reference vehicle height B, as described later (step _S4) . ). Therefore, as will be described later, even when the vehicle height pitches as shown in curves 1 to 3 in FIG. 3, the suspension is made hard. Also, set the mode selection switch 53 to the second
When the mode is set (step S ₅ ), the vehicle height thresholds are set to H as the reference vehicle height A and L as the reference vehicle height B (step S ₅ ), as will be described later. Therefore, even when the vehicle height pitches as shown in curves 1 and 2 in FIG. 3, the suspension is made hard as will be described later. On the other hand, when the vehicle height pitches as shown in 3, the suspension is softened as will be described later. Furthermore, when the mode selection switch 53 is set to the third mode (step _S5 ), the vehicle height thresholds are set to EH as the reference vehicle height A and EL as the reference vehicle height B (step S5). _S7 ). For this reason,
When the vehicle height is pitched as shown by curve 1 in FIG. 3, the suspension is made hard as will be described later. On the other hand, when the vehicle height pitches as shown in 2 and 3, the suspension is softened as described later.

Next, proceed to step _S8 to check the vehicle height sensor 38.
The vehicle height H detected by F, 38R is the controller 3.
6. Then, it is determined whether the vehicle height H is equal to the reference vehicle height A (step _S9 ). now,
If we consider that the vehicle height is changing as shown by curve 3 in FIG. 3, the vehicle height H becomes equal to the reference vehicle height A at time _t1 . In this case, select "YES" in step _S9 .
If it is determined that this is the case, the program proceeds to step _S10 , where it is determined whether or not a memory vehicle height Hm, which will be described later, is smaller than a reference vehicle height A. Here, this memory vehicle height stores the previously detected vehicle height Hm, and as shown in FIG. 3, at time _t1 , the vehicle height is the reference vehicle height A.
The vehicle height Hm is a value smaller than the reference vehicle height A. Therefore, the determination in step _S10 is ``YES'' and the process proceeds to step <sub>S11</sub> . In this step <sub>S11</sub> ,
Timer 1 is started. This timer 1 detects the cycle from when the vehicle height exceeds the reference vehicle height A until it returns to the reference vehicle height B. Next, timer 2, which will be described later, is stopped (step S <sub>12</sub> ). This timer 2 detects the period from when the vehicle height falls below the reference vehicle height B until it returns to the reference vehicle height A. Then, it is determined whether the count value of timer 2 is greater than or equal to <sub>T1</sub> and less than or equal to <sub>T2</sub> . In this case, since the timer 2 has not started the timing operation, the determination is "NO" and the process proceeds to step <sub>S14</sub> , where it is determined based on the cycle whether the hard condition has continued for the set time. If not present, the suspension characteristics will be softened (step
<sub>S15</sub> ). Then, the vehicle height detected by the vehicle height sensors 38F and 38R is stored in the memory vehicle height as the vehicle height Hm. Thereafter, the process returns to step <sub>S2</sub> above. Thereafter, the vehicle height H is detected again in step <sub>S8</sub> . Then, from time t <sub>1</sub> to time t <sub>2</sub> , the determination in step S <sub>9</sub> is "NO", the determination in step S <sub>17</sub> is "NO", and the process returns to step S <sub>2</sub> . During this time, the timer 1 continues to measure time. Then, at time <sub>t2</sub> , the vehicle height H becomes equal to the reference vehicle height A again. Therefore, the determination in step <sub>S9</sub> is ``YES'', but the determination in step _S10 is ``NO'', and the process proceeds to step _S14 and subsequent steps.

Then, at time _t3 , the vehicle height H becomes equal to the reference vehicle height B. Therefore, the determination in step _S9 is "NO", the determination in step _S17 is "NO", and the process proceeds to step _S18 . Proceeding to step _S18 , it is determined whether a memory vehicle height Hm, which will be described later, is greater than a reference vehicle height B. Here, since the reference vehicle height B is smaller than the vehicle height Hm at time _t3 , that is, the vehicle height is decreasing at time _t3 , the determination is ``YES'' and the process proceeds to step <sub>S19</sub> .
Then, in step <sub>S19</sub> , timer 1 is stopped. Next, timer 2 is started (step S <sub>20</sub> ). Then, the count value of timer 1 is T <sub>1</sub>
With the above, it is determined whether or not T <sub>2</sub> or less (step S <sub>21</sub> ).
If ``YES'' is determined in this step _S21 , the suspension characteristics are made hard (step _S22 ). Thereafter, the process advances to step _S16 and the subsequent processing is continued.

The above is set to mode 1 by the mode selection switch 53.
Although the case where mode 2 is selected has been described, the same operation is performed when mode 2 is selected. In the case of mode 1, curves 1 to 3 in Fig. 3 represent the reference vehicle height A.
Because it is larger and smaller than the standard vehicle height B, timer 1
In both cases, the timing operation is not performed. Therefore, the suspension characteristics are softened. In addition, in the case of mode 2, since only curves 1 and 2 in FIG. 3 are greater than the reference vehicle height A and smaller than the reference vehicle height B, timers 1 and 2 both perform timing operations. Therefore, the suspension characteristics are made hard. In addition, in the case of mode 3, only curve 1 in Fig. 3 is larger than the reference vehicle height A and smaller than the reference vehicle height B, so
Timers 1 and 2 both perform timekeeping operations. Therefore, the suspension characteristics are made hard.

In other words, it is possible to increase the frequency of setting the suspension characteristics to hard in the order of modes 3, 2, and 1.

[Effect of idea]

As detailed above, according to the present invention, if the period between the maximum vehicle height values that are equal to or greater than the threshold value selected by the mode selection switch during vertical fluctuation of the vehicle height is within the set time, the suspension characteristics are set to the hard state. Therefore, it is possible to provide a vehicle suspension device in which the suspension characteristics can be freely selected depending on the road surface condition.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a vehicle suspension device according to the present invention, FIGS. 2A and 2B are flowcharts showing the operation, and FIG. 3 is a diagram showing changes in vehicle height. 11... Main air spring chamber, 14... Switching device,
36...Controller, 38F, 38R...Vehicle height sensor, 53...Mode selection switch.

Claims (1)

[Scope of utility model registration request] A vehicle height sensor that detects vehicle height, a switching means that switches suspension characteristics between a hard state or a soft state, and a mode selection switch that can set multiple vehicle height thresholds for determining a pitching state of the vehicle height. If the period between the maximum vehicle height values that are equal to or greater than the threshold value selected by the mode selection switch in the vertical fluctuation of the vehicle height output from the vehicle height sensor is within the set time width, the suspension characteristics are changed by the switching means. A suspension device for a vehicle, comprising a control means for switching the suspension to a hard state.