JPH07242115A - Stabilizer device for vehicle - Google Patents

Abstract

PURPOSE:To ensure an accurate fail-safe function against a trouble in a hydraulic system while switching a stabilizer to an active state at turning time and to a free state at straight advance running time. CONSTITUTION:A cylinder A for supporting an end part of a stabilizer bar and a means B for detecting a steering angle of a vehicle are provided, also to provide a valve means C for switching a circuit, in accordance with this detecting signal, to a free state of the cylinder extensible/contractible, active state in a positive direction of operating in an extension side and an active state in a reverse direction of operating in a contraction side, and to provide a means D for detecting a supply pressure to the cylinder and a fail-safe means E for fixing the valve means to the free state when abnormality of this supply pressure of the means D is decided. A fail-safe means E', waiting the steering angle of the vehicle reset to a straight advancing condition to fix the valve means C in a free condition during active operation of the cylinder A when decided abnormality of the supply pressure, is preferably provided. An alarm means F, operated when decided abnormality of the supply pressure, is additionally provided in the fail-safe means E, E'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle stabilizer device.

[0002]

2. Description of the Related Art A stabilizer device is often adopted as a means for supplementing the roll rigidity of a suspension spring with a bar material of spring steel in order to suppress rolling of a vehicle body and improve running stability (Japanese Utility Model Publication No. 63-104105). , Actual Kaisho 63-15580
No. 8, Japanese Utility Model Publication No. 2-121409, etc.).

Of these, for the purpose of positively reducing the roll of the vehicle body, as shown in FIG. 7, both ends of the stabilizer bar 51 are supported by a frame through single rod type cylinders 52, 53. 53 to hydraulic piping 6
It has been proposed that the connection is made with 5, 66, 67 and the operation of the cylinders 52, 53 is controlled by using the direction switching valve 68 (Japanese Utility Model Laid-Open No. 63-82613).

When the direction switching valve 68 is switched to, for example, the parallel active position P ₃ , the hydraulic pressure from the pump 69 flows to the cylinder 53 on one side and the chamber 6 on the rod side thereof.
4, the piston rod 59 is actuated to the contraction side, so that the chamber 63 on the head side contracts while allowing the hydraulic pressure to escape, and the hydraulic pressure flows to the cylinder 52 on the opposite side to enter the chamber 61 on the head side. Since the rod 58 is actuated to the extension side, the rod-side chamber 62 transfers the hydraulic pressure to the reservoir 70.
Shrink while escaping.

As described above, by switching the direction switching valve 68 to the active position P ₁ which crosses the parallel active position P ₃ in accordance with the turning direction of the vehicle, the cylinder 52 or 53 on one side operates to the extension side. Accordingly, the cylinder 53 or 52 on the opposite side operates toward the contraction side, so that the stabilizer bar 51 can be twisted to generate a moment opposite to the roll of the vehicle body.

In addition to the parallel and cross active positions P ₃ and P ₁ , the directional control valve 68 has hydraulic circuits 65 and 66 on the cylinders 52 and 53 side at their neutral positions.
Since the lock position P ₂ for shutting off is provided, the active stabilizer function and the normal stabilizer function can be selectively exerted.

[0007]

By the way, in this conventional example, since there is no free position for switching the hydraulic pressures of the cylinders 52 and 53 to the free state, the suspension spring has a high roll rigidity. There was a problem that the function of the stabilizer could not be canceled in order to obtain a soft riding comfort when driving straight ahead.

The present invention has been made in consideration of the above problems, and the stabilizer is switched to an active state during turning, and is switched to a free state in which a cylinder absorbs the torsion torque of the stabilizer during straight traveling, and the hydraulic system is operated. An object of the present invention is to provide a stabilizer device having an appropriate fail-safe function against a failure (failure, etc.).

[0009]

In the first invention, FIG.
As shown in (a), a cylinder A that supports the end of the stabilizer bar and a means B that detects the steering angle of the vehicle are provided, and the cylinder is in a freely stretchable free state in accordance with the detection signal and the cylinder extends. Means for detecting the supply pressure to the cylinder and an abnormality thereof are provided, which is provided with a valve means C for switching the circuit between a positive-direction active state that operates on the side and a reverse-direction active state that also operates on the contracted side. A fail-safe means E is provided for fixing the valve means to the free state where the cylinder can freely expand and contract.

In the second aspect of the invention, as shown in FIG. 1 (b), a cylinder A for supporting the end of the stabilizer bar and a means B for detecting the steering angle of the vehicle are provided, and the cylinder of the cylinder is detected according to the detection signal. Detects the supply pressure to the cylinder by providing valve means C that switches the circuit between a free state in which expansion and contraction is possible, a positive direction active state in which the cylinder operates on the extension side, and a reverse direction active state in which the cylinder also operates in the contraction side. Means D
When the abnormality is judged, fail-safe means E'is provided to wait for the steering angle of the vehicle to return to the straight traveling state during the active operation of the cylinder and to fix the valve means to the free state where the cylinder can freely expand and contract.

In the third invention, as shown in FIGS. 1 (a) and 1 (b), the fail-safe means E and E'are provided with an alarm means F which is activated when the supply pressure is judged to be abnormal.

[0012]

According to the first aspect of the invention, since the valve means switches the circuit in accordance with the steering angle of the vehicle, the cylinder is free to expand and contract when going straight and absorbs the twist of the stabilizer bar, while it goes forward or backward when turning. It becomes possible to operate and actively reduce the roll angle of the vehicle body. When some kind of failure occurs in the pressure system, it is judged from the supply pressure to the cylinder and the valve means is fixed to the free state of the cylinder, so that the circuit can be kept at a low pressure even during turning, and the pressure loss may expand. The cylinder can be prevented from abnormally active operation.

According to the second aspect of the invention, the control operation of the cylinder can be ensured as in the first aspect of the invention, and even if the abnormality of the supply pressure is judged during the turning of the vehicle, the cylinder is operated until the vehicle returns to the straight traveling state. Is not fixed in a free state, the roll angle of the vehicle does not suddenly change during turning, and a smooth transition to a straight traveling state is possible.

According to the third aspect of the present invention, since the stabilizer does not work actively by the alarm of supply pressure abnormality, the driver can cope with this and safely drive the vehicle. .

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 2, 20a is a front axle of a vehicle, and 20b is also a rear axle, to which stabilizer bars 21a and 21b respectively have a pair of left and right brackets 22a and 22b with a central portion thereof serving as a torsion bar.
It is attached via. Stabilizer bars 21a, 2
Both ends of 1b are extended along the side rails 23 of the frame, and bushes 24a and 24b are provided at their tips. One side rail 23 has support rods 25a, 2
5b is attached at its upper end via rubbers 26a, 26b, and one-rod type hydraulic cylinders 10a, 10b are pin-connected on the opposite side rail 23 on the head side so as to be horizontally placed along the longitudinal direction of the vehicle.

The stabilizer bars 21a and 21b are provided with bushes 24a and 24b at one end side thereof and support rods 25a and 25b.
The lower ends of the adjusting rods 27a and 27b are pin-coupled to the lower ends of the adjusting rods 27a and 27b by bushes 24a and 24b on the other end side, and bells for converting linear motion into rotational motion between the adjusting rods 27a and 27b and the hydraulic cylinders 10a and 10b. Cranks 28a, 2
8b is provided. The bell cranks 28a and 28b are attached to the side rails 23 at the middle portion of the L shape so as to be freely rotatable in the vertical direction via the shafts, and the bushes 29a and
It is connected to the piston rods of the hydraulic cylinders 10a and 10b via 29b and to the upper ends of the adjusting rods 27a and 27b on the other end side via bushes 30a and 30b. 31a
Is a leaf spring that supports the front axle 20a, and 31b is a leaf spring that supports the rear axle 20b.

Both chambers of the cylinders 10a and 10b have directional control valves 40a and 40b and a pressure control valve 41 as shown in FIG.
Pipes are connected to the pump 42 side and the reservoir 43 side via a and 41b. Accumulators 44a and 44b for accumulating the oil discharged from the pump 42 are provided, and the pressure control valve 41
a and 41b are solenoids SOLe and SOLf for supplying pressures from the accumulators 44a and 44b to the cylinders 10a and 10b.
Adjust according to the excitation force of. Pressure control valves 41a, 41b
Pilot pressure is introduced from the downstream side of the cylinder and is connected to the tank port to the reservoir 43 side in order to mitigate the excessive pressure generated in the cylinders 10a and 10b due to the influence of disturbance or the like. Solenoid SO for direction switching valves 40a and 40b
By controlling the on / off control of the power supply to La, SOLb, SOLc, and SOLd, the circuits on the cylinder side are set to the free state in which the cylinders 10a and 10b can freely expand and contract, and the active state in which the cylinders 10a and 10b are activated in the forward and reverse directions. Is selectively switched.

An unload valve 46 switches the pump 42 to a no-load operation, and a check valve 47 is provided between the pump 42 and the accumulators 44a and 44b to prevent a reverse flow of hydraulic pressure. The unload valve 46 is closed when the solenoid SOLg is energized, and when the energization is turned off, the discharge oil of the pump 42 is reversed without pressure loss.
Escape to 3. Further, a hydraulic pressure cut valve 48 that opens the hydraulic pressure on the accumulators 44a and 44b side to the reverser 43 as necessary, and a pressure sensor and switch 49 that detects the pressure in the accumulators 44a and 44b and operates at the upper and lower limit values thereof. Is provided. The hydraulic cut valve 48 is closed when the solenoid SOLh is energized, and when the energization is turned off, the hydraulic pressure on the accumulators 44a, 44b side is released to the reverser 43. 50 is a relief valve that regulates the maximum discharge pressure of the pump 42, and 51 to 53 are oil filters.

Pressure control valves 41a and 41b and direction switching valve 4
0a, 40b, unload valve 46 and hydraulic cut valve 4
A controller 55 controls 8 and a rudder angle sensor 56 for detecting the rudder angle of the front wheels as a detection means necessary for the control.
In addition to the vehicle speed sensor 57 that detects the traveling speed and the load sensors 58a and 58b that detect the load on each axle, the free state and the active state of the front and rear stabilizers are selectively instructed separately based on human operation. An active mode switch 59 is provided for this purpose. Also,
A mode indicator 60 that displays the operating state of the active mode switch 59 in the cab, a pressure indicator 61 that displays the detection value (pressure value) of the pressure sensor & switch 49, and an alarm buzzer that operates when a hydraulic system failure described later occurs. 62 and a warning lamp 63, the controller 55 outputs respective operation signals to them.

The main control of the controller 55 is represented by functional blocks, as shown in FIG.
7 and lateral G calculation means 65 for calculating lateral acceleration from the detection signals of the steering angle sensor 56, tire cornering power correction means 66 for correcting the calculated value of lateral acceleration from the detection signals of the load sensors 58a and 58b, and the front side. Control pressure determining means 6 for determining the control pressure from the lateral acceleration on the rear side.
7a and 67b, and these determined pressures when the active mode switch 59 is turned on.
0b, 41b, and valve mechanism driving means 68a, 68b for converting and outputting the control signal.

FIG. 5 is a flow chart for explaining the control contents of the controller 55, which is repeatedly executed at a predetermined control cycle. The front axle load, the rear axle load, the vehicle speed, and the front wheel steering angle are read from the detection signals of the respective sensors, and the lateral acceleration α and the control pressure for the calculated value are calculated based on these signals (1.01 to 1.06). Solenoid SOL of unload valve 46 when active mode switch is off
g is turned off, the solenoid SOLh of the hydraulic cutoff valve 48 is turned off until the pressure sensor & switch 49 is turned on at the lower limit value, the solenoids SOLa to SOLc of the direction switching valves 40a and 40b are turned off, and the solenoids SOL of the pressure control valves 41a and 41b are turned off.
e, SOLf is turned off (1.07 to 1.13, 1.07 '
~ 1.13 '). As a result, the pump 42 is switched to the no-load operation, and the hydraulic pressure on the accumulators 44a and 44b side is maintained at the lower limit value. At the same time, since the directional control valves 40a, 40b connect both chambers of the cylinders 10a, 10b to the reservoir 43, the cylinders 10a, 10b can freely expand and contract to absorb the twist of the stabilizer bars 21a, 21b.

When the active mode switch 59 is turned on, the solenoid SOLh of the hydraulic cut valve 48 is turned on and the solenoid SOLg of the unload valve 46 is turned on / off (1.14, 1.15, 1, 14 ', 1. 1
5 '). In other words, when the pressure sensor & switch 49 is turned on at the upper limit value, the unload valve 46 turns off the solenoid SOLg to turn the hydraulic pressure on the accumulators 44a, 44b side into the reservoir 4.
When the pressure sensor & switch 49 is turned on at the lower limit value while being opened to 3, the discharge oil of the pump 42 is accumulated in the accumulators 44a, 44b by turning off the solenoid SOLg.

The reference value ± g ₀ for judging the straight traveling state and the turning state of the vehicle is compared with the calculated value of the lateral acceleration α, and according to the judgment, when the lateral acceleration α is + g ₀ or more, the directional control valve 40a, 40b for parallel communication position,-
-g _{0 for the} communication position that crosses when g ₀ or less
To on-off energization of the solenoid SOLa~SOLd to switch to open Pojisshon at _{~ + g 0 (1.16~1.22,1.16'~1.22 ')} . At the same time, the solenoids SOL of the pressure control valves 41a and 41b are
The operation of the cylinders 10a and 10b is controlled by changing the amount of electricity supplied to e and SOLf according to the calculated value of the control pressure (1.23, 1.24, 1.23 ', 1.24').

The lateral acceleration α of the cylinders 10a and 10b is +
When g ₀ or more, the directional control valves 40a, 40 are provided in the rod side chamber.
The supply pressure is received from the pressure control valves 41a and 41b through b, and the piston rod contracts while releasing the hydraulic pressure from the head side chamber to the reservoir 43. When the lateral acceleration α is −g ₀ or less, the head side chamber receives the supply pressure, and the piston rod extends while releasing the hydraulic pressure in the rod side chamber. −g ₀ to + g ₀
In the case of the head side chamber and the rod side chamber,
Since the piston rod is opened to the reservoir 43 through 40b, the piston rod can freely expand and contract.

When the vehicle goes straight (lateral acceleration α is -g ₀ to + g ₀
Range is the same as when the active mode switch 59 is off.
a and 10b are freely expandable and contractible, and stabilizer bars 21a and 21a
Since the twist of b is absorbed, the function of the stabilizer is canceled and a soft riding comfort of the vehicle is obtained. When the vehicle turns due to a lane change or the like, the cylinders 10a and 10b respectively act on the extension side with respect to the lateral acceleration α of −g ₀ or less and on the contraction side with respect to the lateral acceleration α of + g ₀ or more. Stabilizer bar 21
a, 21b can be generated.

In this case, the supply pressure to the cylinders 10a and 10b is not constant and is controlled by the controller 55 according to the lateral acceleration α accompanying the turning of the vehicle, so that a natural active characteristic proportional to the vehicle speed state can be obtained. In addition, when the vehicle shifts to the straight traveling state, the cylinders 10a and 10b can be appropriately returned to the neutral position. Also, the lateral acceleration α
Since the axle load is added to the vehicle speed and the steering angle in the calculation processing of 1, the roll angle of the vehicle body can be reduced to the target value even if the load amount changes.

By the way, in order to ensure safe active operation of the cylinders 10a and 10b, the controller 55 stores a fail-safe function for a failure (failure or the like) of the hydraulic system. FIG. 6 is a flow chart for explaining the control contents. When the active sw 59 is on, the detection value (pressure value) of the pressure sensor & switch 49 is compared with the upper limit value and the lower limit value of the accumulators 44a, 44b, and this is the upper limit value. When the value is out of the normal range of the lower limit value, that is, higher than the upper limit value or lower than the lower limit value, the abnormality of the hydraulic system is determined (2.01 to 2.03). After checking the straight traveling state of the vehicle with the detection value of the steering angle sensor 56 at the time of abnormality determination, the solenoid SOLh of the hydraulic cut valve 48 and the solenoid SOLg of the unload valve 46 are turned off, and the solenoid SOLa of the direction switching valves 40a and 40b. ..- SOLd are both turned off, and the alarm buzzer 62 and the warning lamp 63 in the cab are operated (2.04 to 2.09).

Since the cylinders 10a and 10b are freely expanded and contracted and the hydraulic circuit is kept at a low pressure, even if the hydraulic pressure is lost, the amount of leakage can be minimized. Also,
Rather than performing active operation when the oil pressure is abnormally high,
By fixing the cylinders 10a and 10b in a free state, the safety of the vehicle can be ensured. Moreover, the alarm buzzer 6
2 and the warning lamp 63 are activated to notify the abnormality of the hydraulic system, the driver can handle the situation and safely turn the vehicle even if the stabilizer does not work actively.

When the cylinders 10a and 10b are turned, the roll angle of the vehicle body may change abruptly if the active state is switched to the free state due to a hydraulic system failure. In this example, however, the fail-safe state is confirmed after confirming the straight running state of the vehicle. Since the processing is performed, the stability of the vehicle body is not significantly impaired during turning. At that time, the lower limit value and the upper limit value of the accumulators 44a and 44b are set to the reference values for the abnormality determination until the vehicle shifts to the straight traveling state.
The cylinders 10a and 10b are activated by the accumulated pressure of a and 44b. The operation of the alarm buzzer 63 and the warning lamp 64 may be stopped by turning off the active mode switch 59.

[0030]

In summary, according to the first aspect of the present invention, the cylinder supporting the end portion of the stabilizer bar and the means for detecting the steering angle of the vehicle are provided, and the cylinder can freely expand and contract according to the detection signal. State, a positive direction active state in which the cylinder operates on the extension side, and a valve means for switching the circuit between an active state in the reverse direction in which the cylinder side also operates on the contraction side, and means for detecting the supply pressure to the cylinder, and Since fail-safe means is provided to fix the valve means to the free state where the cylinder can freely expand and contract when an abnormality is judged, the function of the stabilizer is canceled when the vehicle goes straight to obtain a good riding comfort, and the stabilizer is active when turning. It is possible to reduce the roll angle of the vehicle body by operating the switch. Also, if any failure occurs in the pressure system,
Since the cylinder is fixed in the free state, the circuit can be kept at a low pressure even during turning, so that it is possible to prevent the loss of pressure from expanding and the cylinder from abnormally active operation.

The control operation of the cylinder can be secured as in the first aspect of the invention, and even if the supply pressure is abnormal during the turning of the vehicle, the cylinder is not fixed in the free state until the vehicle returns to the straight traveling state. There is no sudden change in the roll angle of the vehicle during turning, and it is possible to smoothly shift to the straight traveling state.

According to the second aspect of the invention, the cylinder for supporting the end portion of the stabilizer bar and the means for detecting the steering angle of the vehicle are provided, and the cylinder is free to expand and contract according to the detection signal and the cylinder. Is equipped with valve means for switching the circuit between a positive active state in which the cylinder operates on the extension side and an active state in the reverse direction that also operates on the contraction side, and means for detecting the supply pressure to the cylinder and the abnormality thereof are determined. During the active operation of the cylinder, the fail-safe means is provided to wait for the steering angle of the vehicle to return to the straight running state and to fix the valve means to the free state where the cylinder can freely expand and contract.
The control operation of the cylinder can be ensured as in the first aspect of the invention, and even if the supply pressure is abnormal during the turning of the vehicle, the cylinder is not fixed in the free state until the vehicle returns to the straight traveling state. There is no sudden change in the corner, and you can safely and smoothly transition to the straight-ahead state.

According to the third invention, in the first or second invention, the fail-safe means is provided with an alarm means which is activated when the supply pressure is judged to be abnormal. Since the notification is given, the driver can cope with this and also have the advantage that the vehicle can be safely driven.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention.

FIG. 2 is a mechanical configuration diagram showing an embodiment of the present invention.

FIG. 3 is a hydraulic circuit diagram of the cylinder.

FIG. 4 is a block diagram which also constitutes a main part of the controller.

FIG. 5 is a flowchart for explaining the control contents of the controller.

FIG. 6 is a flowchart for explaining the control contents of the controller.

FIG. 7 is a schematic configuration diagram illustrating a conventional technique.

[Explanation of symbols]

 10a, 10b Hydraulic cylinder 20a Front axle 20b Rear axle 21a, 21b Stabilizer bar 40a, 40b Directional switching valve 41a, 41b Pressure control valve 42 Pump 43 Reservoir 44a, 44b Accumulator 46 Unload valve 47 Check valve 48 Hydraulic cut valve 49 Pressure sensor & Switch 55 Controller 56 Steering angle sensor 57 Vehicle speed sensor 58a, 58b Axle load sensor 59 Active mode switch 62 Alarm buzzer 63 Warning lamp

Claims (3)

[Claims] 1. A cylinder for supporting an end portion of a stabilizer bar, and means for detecting a steering angle of a vehicle are provided, and the cylinder is freely extended and contracted according to the detection signal, and the cylinder is operated to extend. A valve means is provided for switching the circuit between an active state in the forward direction and an active state in the reverse direction, which also operates on the contraction side. The means for detecting the supply pressure to the cylinder and the valve means for expanding and contracting the cylinder when the abnormality is judged. A stabilizer device for a vehicle, comprising: a fail-safe means for fixing in a free and free state. 2. A cylinder for supporting an end portion of a stabilizer bar and means for detecting a steering angle of a vehicle are provided, and the cylinder is in a freely extended / retracted free state in accordance with the detection signal, and the cylinder is operated on the extension side. It is equipped with valve means for switching the circuit between a positive-direction active state and a reverse-direction active state that also operates on the contraction side, means for detecting the supply pressure to the cylinder, and when the abnormality is judged, during active operation of the cylinder A stabilizer for a vehicle, comprising: a fail-safe means for fixing the valve means to a free state in which the cylinder can freely expand and contract after waiting for the steering angle of the vehicle to return to the straight traveling state. 3. The stabilizer device according to claim 1, wherein the fail-safe means includes an alarm means which is activated when the supply pressure is determined to be abnormal.