JPS5940914A - Vehicle attitude control device - Google Patents

Abstract

PURPOSE:To enhance a drive feeling and the durability of a device, in a vehicle attitude control device for preventing a vehicle from rolling, by providing such an arrangement that the damping force and spring constant of a suspension system are maintained at high values for a predetermined time period after the condition of rolling is vanished. CONSTITUTION:Signals from steering angle sensors 21A, 21B and a vehicle speed sensor 22 are delivered to AND circuits 25A, 25B through comparators 24A, 24B, respectively. When the AND circuits 25A, 25B are turned on due to the relationship between the steering angle and the vehicle speed, an OR circuit 26 delivers a rolling discriminating signal to an OR circuit 28 so that a rotary solenoid and a solonid valve which are not shown are operated by means of a drive circuit 27 to control the attitude of the vehicle. Then, when the rolling is eliminated and the signal disappears, a hold circuit 29 issues pulses having a predetermined time width for a predetermined time period to maintain the OR circuit 28 and the drive circuit 27 in their operating conditions for holding the condition of the attitude control. With this arrangement, inertial swinging-back may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an attitude control device that suppresses rolling when a vehicle turns.

Conventionally, for example, in order to suppress rolling when a vehicle turns,
Japanese Utility Model Application Publication No. 56-42739 and Japanese Utility Model Application Publication No. 56-14710 are known to increase the damping force of a hydraulic shock absorber to prevent the vehicle body from tilting to the left or right when the steering wheel is operated at a predetermined vehicle speed or higher. -1- It has been proposed.

Incidentally, in this case, the damping force is increased only while the steering wheel is being turned, that is, when the vehicle is in a state where rolling may occur, and thereafter the damping force is immediately returned to its original low state.

However, even if this method prevents rolling when changing lanes, for example, it cannot prevent rolling back due to the inertia of the vehicle that occurs immediately after, and in this respect, the original anti-rolling function is not necessarily effective. There were aspects that could not be said to be fully demonstrated.

In addition, even when driving off-road, such as during slalom, the damping force returns to its original state every time the direction changes when meandering left and right, resulting in a poor feeling.Also, the control means frequently turns on and off, making durability difficult. There is also the problem of lowering it.

The present invention increases the damping force and spring constant of the suspension when it detects a rolling condition in which the vehicle posture changes and impairs steering stability, and also increases the damping force and spring constant of the suspension for a while after this driving condition ends. -2- It is an object of the present invention to provide a vehicle attitude control device that solves the above problem by maintaining the same control state.

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, 1A and IB indicate hydraulic shock absorbers for the front wheels, and 1C and 21D indicate hydraulic shock absorbers for the rear wheels.

Each hydraulic shock absorber 1A to 1D generates a damping force as described below.
By driving the low pressure solenoid 3, the spring constant of the air spring chamber 5 formed through the rubber sleeve 4 can be selectively controlled with the accumulator 7 by switching the spring constant of the air spring chamber 5 formed through the rubber sleeve 4. It can be changed by connecting to.

That is, when the left and right air spring chambers 5 are communicated with each other and the capacity of the accumulator 7 is added, the air spring constant is small and the nonlinearity of the spring load with respect to the shock absorber stroke is relatively weak. On the other hand, if the communication between the left and right air spring chambers 5 is cut off by the electromagnetic switching valve 6 and also separated from the accumulator 3-7, the effective capacity of the air spring chamber 5 changes greatly with respect to the shock absorber stroke, resulting in nonlinearity of the air spring constant. Since the spring can be strongly rolled, the spring constant can be rapidly increased for a small stroke.

As shown in FIG. 2, the hydraulic shock absorbers 1A to 1D have a piston 12 housed inside a double cylinder made up of an inner tube 10 and an outer tube 11, so that the upper oil chamber A,
A lower oil chamber B and an oil reservoir chamber C are partitioned.

The piston rod 13 is connected to the vehicle body side, and the outer tube 11 is connected to the wheel side.

Although not shown in the drawings, the piston 12 is equipped with expansion-side and compression-side damping valves, and during compression-side operation when the piston rod 13 enters, hydraulic oil is supplied from the lower oil chamber B to the expanding upper oil chamber A. The oil flows in through the pressure side damping valve, and at this time, a predetermined flow path resistance is applied to generate a pressure side damping force, and at the same time, surplus oil corresponding to the entering volume of the piston rod 13 is released to the outer oil reservoir chamber C. When the piston rod 13 is pulled out and operated on the extension side, hydraulic oil flows from the upper oil chamber A to the expanding lower oil chamber B via the extension side damping valve, and the damping force is exerted in the same manner as above. be.

A passage 15 that communicates the upper and lower oil chambers A and B, bypassing the piston 12, is formed inside the piston rod 13, and a switching valve 16 is interposed in the middle of this passage 15.

The switching valve 16 is connected to an operating rod 17 that passes through the piston rod 13 in the axial direction, and opens and closes the passage 15 by rotating the operating rod 17.

1. This operating rod 17. The aforementioned rotary solenoid 3
The damping force is relatively increased when the passage 15 is closed compared to when it is open.

By the way, the lateral acceleration that causes the vehicle body to roll when the vehicle turns is determined by predetermined conditions, such as when the steering angle is small but the vehicle speed is high, or when the vehicle speed is low but the steering angle is large.

Therefore, a control circuit 20 for operating the rotary solenoid 3 and the electromagnetic switching valve 6 is constructed as shown in FIG.

Sensors 21A and 21B detect the steering angle of the front wheels, and the sensor 21A detects a large steering angle and the sensor 21B turns ON when the steering angle is small. 22 is a vehicle speed sensor that outputs a signal according to the vehicle speed, and this output is sent to comparators 24A and 2.
Enter in 4B.

The comparators 24A and 24B are input with voltages V, V2 corresponding to low and high vehicle speeds, respectively, as comparison reference values, and when the vehicle speed signal exceeds this reference value, the respective outputs turn ON (high). level).

AND circuits 25A and 25B have outputs of steering angle sensors 21A and 21B on one side and comparators 24A and 24 on the other side, respectively.
The output of B is input, and when both of them are ON, the output is turned ON, and the OR circuit 26 outputs a rolling determination signal when any one of the outputs of the AND circuit 25A25B is turned ON.

The rolling judgment signal is directly input to one input terminal of the OR circuit 28, and at the same time is also input to a hold circuit 29 consisting of a constant multivibrator or the like, and the hold circuit 29 triggers the fall of the rolling judgment signal. and then OR the pulse with a predetermined time width.
The other input terminal of circuit 28 is supplied.

The time width of the output pulse of the hold circuit 29 is set to the time necessary to prevent the vehicle from shaking back immediately after turning, for example, 2 to 3 seconds.

Then, the output of the OR circuit 28 is determined when either input is ON.
(High level), an ON signal is sent to the drive circuit 27 during that time, and the drive circuit 27 energizes the rotary solenoid 3 and the electromagnetic switching valve 6 to switch them.

Next, the operation will be explained with reference to FIG.

When the vehicle turns, if the steering angle of the steering wheel is small, the vehicle speed at that time must be quite high, and even if the steering angle is large, the vehicle body will not roll if the vehicle speed is small.

Therefore, in such a case, the AND circuit 25-7
- Since neither of the inputs A and 25B are turned ON, the AND circuits 25Δ and 25B remain OFF, and the OR circuit 26 does not output a rolling determination signal to the drive circuit 27.

In this state, the rotary solenoid 3 is not excited and the damping force is not switched; that is, the switching valve 16 opens the passage 15, and a low damping force is generated with emphasis on ride comfort.

Further, the air spring electromagnetic switching valve 6 is also located at the position shown in FIG. 1, and allows the air spring chambers 5 of the left and right hydraulic shock absorbers 1A and 1B and 1G and 1D to communicate with each other and with the air accumulator 7.

This reduces the spring constant and maintains a soft ride.

On the other hand, when the lateral acceleration exceeds a certain value, that is, when one of the AND circuits 25A and 25B is turned on, the OR circuit 26 outputs a rolling determination signal.

In other words, even when only the comparator 24A is ON in the low vehicle speed range, when the steering angle is large and the output of the sensor 21A is ON, or when the steering angle is small enough that only the sensor 21B is ON. Comparator 24A when the vehicle speed is in the high speed range.
, 24B is ON, the AND circuit 25A
25B is turned ON.

As a result, based on the rolling determination signal from the OR circuit 26, the drive circuit 27 energizes the rotary solenoid 3 and the electromagnetic switching valve 6 via the OR circuit 28.

Then, the switching valves 16 of the hydraulic shock absorbers 1A to 1D switch to the passage 15.
is closed, the damping force is switched to a higher value, and communication between the air spring chambers 5 is cut off to increase the spring constant.

As a result, the hydraulic shock absorbers 1A to 1D prevent the vehicle body from tilting to the left or right (although the shock absorbers on the outside of the rotation actually contribute to preventing the vehicle from sinking), improving running stability when turning. This is to ensure that

According to this embodiment, when the lateral acceleration falls below a certain value and the rolling determination signal disappears, the hold circuit 29 simultaneously outputs a pulse having a time width of, for example, 2 to 3 seconds. OR circuit 28
Since the signal continues to be inputted to the drive circuit 27 through the above, the drive circuit 27 continues to operate the rotary solenoid 3 and the electromagnetic switching valve 6 as it is. This prevents the inertia energy of the vehicle body from causing the vehicle to swing back immediately after the turn is completed.
It effectively prevents it.

Figure 4 is a time chart showing such an operating state, and when the rolling judgment signal is input again after a short period of time, the high damping force and spring constant are maintained by the function of the hold circuit 29. .

Therefore, under driving conditions in which rolling occurs repeatedly, steering stability can be reliably improved by maintaining a stiff suspension.

Next, the embodiment shown in FIG. 5 will be described. In this embodiment, rolling is determined from the steering angle θ and the square of the vehicle speed v2.

The output of the steering angle sensor 31 is amplified by an amplifier 32 and input to one terminal of a multiplier 33 (θ).

-10- Also, the output of the vehicle speed sensor 34 consisting of a crank angle sensor etc. is converted into an analog voltage according to the frequency by the F-V converter 35, amplified by amplifiers 36 and 37, and multiplied by a multiplier 38. (v2) The signal is further amplified by the amplifier 39 and inputted to the terminal of the multiplier 33. The multiplier 33 multiplies these to obtain θ·v2, the comparator 40 compares the calculation results, and outputs a rolling determination signal to the hold circuit 29 and drive circuit 27 when the result is greater than a predetermined value.

Further, in the embodiment shown in FIG. 6, rolling is determined from the relationship between the steering angular velocity θ and the vehicle speed.

Therefore, the output of the steering angle sensor 31 is differentiated (θ) by the differentiating circuit 44, and this is amplified by the amplifier 41 (aθ).
. Then, the output of the vehicle speed sensor 34 is frequency-voltage converted by the F-V converter 35 and amplified by the amplifier 42 (bv
).

The outputs of these double width transducers 41 and 42 are input to the differential amplifier 43, and the subtraction of the two, that is, (aθ-bv) is obtained.

-11- Generally, for a constant lateral acceleration, as the vehicle speed V increases, the steering angular velocity θ tends to decrease. Therefore, when the lateral acceleration exceeds a certain value, a[theta]-hv exceeds a predetermined value and rolling occurs, so a rolling determination signal is output in such a case, as described above.

In the above embodiment, both the hydraulic shock absorber and the air spring are controlled according to the rolling determination signal, but either the hydraulic shock absorber or the air spring may be controlled.

As described above, the present invention maintains the attitude correction control for a short time even after the rolling state in which the vehicle attitude changes is released, so that the inertial energy of the vehicle body prevents the vehicle from rolling back. It can reliably prevent this and improve maneuverability.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of the present invention, Fig. 2 is a sectional view of a hydraulic shock absorber, Fig. 3 is a block diagram of a control circuit, Fig. 4 is a flow chart of control operation, Fig. 5, 12-6 Each figure is a block diagram of a control circuit according to another embodiment. 1A to 1D...Hydraulic shock absorber, 3...Rotary nozzle, 5...Air spring chamber, 6...Solenoid switching valve, 7...
・Accumulator, 10.11...Tube, 12
...Piston, 13...Piston rod, 15...
-Passage, 16...Switching valve, 20...Control circuit, 21
A, 21B... Steering angle sensor, 22... Vehicle speed sensor, 24A, 24B... Comparator, 25A, 25B...
AND circuit, 26.28...OR circuit, 29...Hold circuit. Patent applicant: Toyo Kogyo Co., Ltd. Kayaba Kogyo Co., Ltd. -13- Commissioner of the Patent Office Kazuo Wakasugi 1. Display of the case 1982 Patent Application No. 151307 2, Name of the invention Vehicle attitude control device 3, Person making the amendment Relationship to the case Patent applicant address 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Name (313)
) Toyo Kogyo Co., Ltd. (and 1 other person) 4, Agent address: 5, 3rd floor, 8-10 Pill, Ginza, 8-10-8, Ginza, Chuo-ku, Tokyo 104, Date of amendment order: Voluntary 6, Subject of amendment: 7. On the 17th to 18th lines of the first page of the specification of the contents of the amendment, the words "Japanese Utility Model Application Publication No. 56-42739 and Japanese Utility Model Application Publication No. 56-14710" have been replaced with "Japanese Utility Model Application Publication No. 56-42739 and Japanese Utility Model Application Publication No. 56-14710". Jitsukai 1976
-147107 Publication”.

Claims (1)

[Claims] Vehicle attitude comprising: means for detecting a rolling condition of the vehicle; and control means for increasing at least one of a damping force and a spring constant of a suspension so as to correct the vehicle attitude while detecting the rolling condition. What is claimed is: 1. A vehicle attitude control device comprising: a holding means for holding the control means for a predetermined period of time after the rolling state disappears;