JPH06106948A - Operation control device for road surface sensor - Google Patents

Abstract

PURPOSE:To switch a suspension characteristic always by the optimum timing against a delay of a control system total unit in a running total region by mounting a road surf ace sensor movably or angle-changeably to a car body, in control of switching the suspension characteristic by the road surface sensor. CONSTITUTION:Suspensions 5, 5' for variably controlling respective damping force are arranged in front and rear wheels 2, 3, and a sensor operating unit 60 is hung down to be mounted to the lower part of a fender apron before the front wheel in a front car body 1, to mount a road surf ace sensor 10 for detecting irregularity of a road surface to this sensor operating unit 60. Particularly at the time of intermediate and high speed the road surface sensor 10 itself is protruded to move to the front of a skirt by the sensor operating unit 60, to move a road surface detecting position to a position, in which the sensor shortest longitudinal distance is subtracted from a distance advanced by a car speed and a delay time of a control system total unit, and at least the timing of the front wheel 2 reaching the road surface detecting position always almost agrees with the timing of switching the damping force of the front wheel suspension 5 by containing the delay time of a control system.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a road surface sensor for detecting a road surface condition in a suspension control device provided on each wheel of a vehicle and switching suspension characteristics in accordance with the unevenness of the road surface.

[0002]

2. Description of the Related Art Generally, a suspension is provided between a vehicle body and an axle of each wheel of a vehicle having a spring and a shock absorber. The spring absorbs a shock from the road surface, and a continuous vibration of its bounce is received by the shock absorber. Is dampened by, and shocks are alleviated. For this reason, if the damping force of the shock absorber is large, the stability of the vehicle posture can be improved by suppressing the rolling of the vehicle body, etc., but it will react ruggedly to the unevenness of the road surface, resulting in a rugged riding comfort. On the contrary, if the damping force is small, the vibration input from the road surface is reduced and the ride comfort is soft. For this reason, in recent years, a damping force variable device has been added to the shock absorber to control the damping force of the suspension characteristics according to the road surface conditions on good and bad roads and the running conditions such as braking, starting, turning, etc. A semi-active suspension system has emerged that makes it possible to achieve both a comfortable ride and a comfortable ride.

Here, in the control for switching the suspension characteristics to the unevenness of the road surface, a road surface sensor such as an ultrasonic system for detecting the unevenness of the road surface is provided at the front part of the vehicle body. In this case, if the road surface sensor is kept fixed, the time when the wheel actually reaches the road surface detection position by the road surface sensor changes depending on the vehicle speed. In addition, the sensor system, control system, and actuator system have their own delay time. Considering the delay time of the entire control system, the road surface information detected by the road surface sensor is used to change the suspension characteristics when the vehicle speed exceeds a certain speed. There is no time to use it, and it will not be possible to make changes at optimal timing. So in the whole traveling area of the vehicle,
It is required to control the timing at which the wheels reach the road surface detection position and the timing at which the suspension characteristics are changed in consideration of the delay time of the entire control system so as to always coincide with each other.

Conventionally, as for the suspension characteristic switching control for the unevenness of the road surface, for example, Japanese Patent Laid-Open No. 3-182 has been proposed.
There is a prior art of Japanese Patent No. 825. Here, it is shown that a road surface unevenness sensor is provided below the front end of the vehicle body and the suspension characteristics are switched based on the sensor output.

[0005]

By the way, in the above-mentioned prior art, since the road surface unevenness sensor is fixedly provided on the vehicle body, the road surface which is always separated by a certain distance in front of the front wheels is detected. At high speeds, the suspension characteristics may not be switched at an optimal timing due to the delay time of the entire control system.

The present invention has been made in view of this point, and in the suspension characteristic switching control by the road surface sensor, the road surface sensor is mounted on the vehicle body so as to be movable or changeable in angle, and the delay of the entire control system is delayed over the entire traveling range. On the other hand, the purpose is to always switch the suspension characteristics at the optimum timing.

[0007]

In order to achieve the above object, the present invention provides a vehicle in which a suspension for switching control of a damping force is provided on a wheel, in a lower part of a fender apron in front of a front wheel of a vehicle body. A sensor actuating device that operates by an electric signal from the control unit is hung and attached, and a road surface sensor that detects unevenness of the road surface is projected to the front from the position of the shortest front and rear distance inside the skirt to detect the road surface. It is mounted so that the position can be sequentially moved forward.

[0008]

According to the above structure, the road surface sensor is attached to the lower part of the fender apron in front of the front wheel of the vehicle body by the sensor actuating device, so that the road surface in front of the front wheel is always accurately detected. The suspension damping force is switched and controlled by. Then, for example, at medium and high speeds, the sensor actuating device causes the road surface sensor to move forward in the forward direction of the skirt, so that the road surface detection position is moved to a position obtained by subtracting the shortest sensor front-rear distance from the distance traveled by the vehicle speed and the delay time of the entire control system. It Therefore, at least the timing at which the front wheels reach the road surface detection position and the timing at which the damping force of the front wheel suspension can be switched, taking into account the delay time of the control system, will always be approximately the same, thus ensuring a stable vehicle attitude throughout the entire traveling range. Can be converted.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. An outline of a vehicle suspension control system will be described with reference to FIG. Reference numeral 1 denotes a vehicle body, and a suspension 5, between the axle 4 of the front wheels 2 and the rear wheels 3 and the vehicle body 1.
5'is installed respectively. Front wheel suspension 5
Is configured such that a spring 6 and a variable damping force type shock absorber 20 are provided in parallel between the vehicle body 1 and the axle 4, and an electric motor 7 is provided above the shock absorber 20 as an actuator for switching control of the damping force. To be done. The rear wheel suspension 5'has the same configuration, and the same parts are denoted by the same reference numerals with a dash and the description thereof is omitted.

In front of the front wheel 2 of the vehicle body 1, a road surface sensor 10 for detecting unevenness of the road surface is attached to a sensor operating device 60 so that the road surface detection position can be changed. Further, it has a vehicle speed sensor 13 for detecting a traveling state. The signals of the road surface sensor 10 and the vehicle speed sensor 13 are input to the control unit 14, and the output signals of the control unit 14 are used to output the motors 7 and 7'of the front and rear wheel suspensions 5 and 5 '.
And a sensor actuating device 60.

The control unit 14 selects the damping force switching signal according to the road surface information, and controls the output timing of the damping force switching signal and the road surface detection position with respect to the delay of the control system. That is, the vehicle speed is V, the delay time of the entire control system is Δt, the shortest front-rear distance between the sensor and the tire center is Lo, the sensor movement amount is ΔL, and the delay time adjusted when the road surface unevenness information is used for control is ΔT. Then, the following equation holds. (Lo + ΔL) / V = Δt + ΔT Therefore, when the vehicle speed V is a low speed equal to or lower than the set vehicle speed Vs (Lo / Δt), the delay time ΔT is set in the sensor fixed state of ΔL = 0.
Is determined by ΔT = Lo / V−Δt, and the damping force switching signal is output to the front and rear wheel suspensions 5 and 5 ′. Further, when the vehicle speed V is equal to or higher than the set vehicle speed Vs and the delay time cannot be calculated, the medium speed is ΔT = 0. And the sensor movement amount Δ
L is determined by ΔL = V · Δt−Lo, and a movement signal is output to the sensor operating device 60.

Referring to FIG. 2, a concrete configuration of the damping force type shock absorber 20 will be described. In the shock absorber 20, a rod 22 on the vehicle body 1 side has a piston 23 and is movably inserted into a cylinder 21 on the axle 4 side. The piston 23 divides the rod 22 into an upper chamber 24 and a lower chamber 25 and fills with oil O. To be done. The piston 23 is provided with an extension side main passage 26 and a main valve 26a, and a contraction side main passage 27 and a main valve 27a. When the rod is extended and the main valve 26a is opened, the oil O flows from the upper chamber 24 to the lower chamber 25 through the main passage 26. Conversely, when the rod is compressed and the main valve 27a is contracted, the other main valve 27a is opened. Open lower chamber 25
From the oil O flows into the upper chamber 24 via the main passage 27. Here, the orifice diameters of the main passages 26 and 27 are set to be small, so that a hard damping force is generated on the extension side and the contraction side.

A damping force varying device 30 is provided inside the rod 22. This damping force varying device 30
A communication hole 31 is provided at the center of the rod 22 so that the lower end thereof communicates with the lower chamber 25, and the communication hole 31 extends toward the extension side sub passage 3.
2 and the sub-valve 32a, the contraction-side sub-passage 33 and the sub-valve 33a, and the sub-passage 34 that serves both functions, and communicates with the upper chamber 24. Further, a shutter 35 from the motor 7 is rotatably inserted into the communication hole 31 via a connecting rod 36, and three types of holes 38, 3 are formed on the circumference of the shutter 35.
9, 40 are provided by being displaced by a predetermined rotation angle.

Therefore, when the shutter 35 is rotated by a predetermined angle by the motor 7 and only the hole 38 communicates with the sub passage 32, the sub valve 32a is contracted when the rod 35 contracts by descending the rod.
Closes. When the rod rises and extends, the sub-valve 32a also opens, and the oil O in the upper chamber 24 also flows into the sub-passage 32 to increase the orifice diameter. This causes the extension side to be soft and the contraction side to be hard in the first mode in FIG. It becomes the damping force characteristic of. Next, when the other hole 39 is communicated with the sub passage 33 by the motor 7, in this case, the sub valve 33a is also opened to increase the orifice diameter only when the rod is contracted by the downward movement of the rod contrary to the above description. The damping force characteristic of the second mode in FIG. 3 is hard and soft on the contraction side. Further, the motor 7 causes the other hole 40 to move to the sub passage 3
In this case, since the oil O always flows through the sub passage 34 to increase the orifice diameter in this case, both the extension side and the contraction side have slightly soft third mode damping characteristics in FIG.
In this way, the motor 7 can obtain damping characteristics of three types of modes.

The mounting structure of the road surface sensor 10 will be described with reference to FIGS. 4 and 5. Monocoque body 1
In the front body 45, the left and right fender aprons 46 are formed by bending appropriately. The lower part of the fender apron 46 is connected to the side member 47, and the front part is connected to the cross member 48 and the radiator support 49. 50 are configured. And the fender apron 46, the radiator support 49, and the front fender 5
1, a bumper 52, a head lamp 53, a skirt 54, a hood 55, etc. are mounted, a front wheel 2 is housed in a wheel house 56, and an engine 57 and various parts are mounted inside an engine room 50. Here, the portion of the fender apron 46 immediately in front of the front wheel is located below the vertical portion 4 via the upper hood receiving portion 46a, the vertical portion 46b, and the horizontal portion 46c.
A part 58 such as a battery and an air cleaner is installed inside the horizontal portion 46c. Since the horizontal portion 46c and the vertical portion 46d are relatively long in the front-rear direction, the sensor actuating device 60 is attached using the space outside these portions.

The sensor actuator 60 includes a mounting plate 66 having an L-shaped cross section outside the vertical portion 46d of the fender apron 46.
Are fixed horizontally, and a bracket 61 is suspended in front of the mounting plate 66 and the radiator support 49. Further, the road surface sensor 10 is fixed to the tip of the long linear rail 62 so as to face right below so as to detect the unevenness of the road surface, and the rail 62 is attached to the bracket 61 via the roller 63. On the other hand, the motor 6 is attached to the rack 62a of the rail 62.
The pinion 65 of No. 4 meshes with each other, and a notch 54a is provided at a part of the skirt 54 where the pinion 65 coincides with the road surface sensor 10. In this way, the road surface sensor 10 is configured so as to be sequentially projected forward of the skirt 54 and horizontally moved by a motor drive from the shortest front and rear distance accommodated in the skirt 54.

Next, the operation of this embodiment will be described. First, at a low speed equal to or lower than the set vehicle speed Vs, the road surface sensor 10 is fixed to the position of the shortest front-back distance Lo retracted inside the skirt 54 by ΔL = 0 by the motor 64 of the sensor operating device 60 by a signal from the control unit 14. It As a result, the road surface sensor 10 always accurately detects the road surface immediately before the front wheel 2. Further, road surface information from the road surface sensor 10 is input to the control unit 14, a damping force characteristic suitable for unevenness is determined, and the damping force switching signal is used as the damping force switching signal for the motors 7 of the shock absorbers 20, 20 'of the front and rear wheel suspensions 5, 5'. , 7'at the same time.

In this case, the output timing of the damping force switching signal is the delay time ΔT obtained by subtracting the delay time Δt of the entire control system from the time Lo / V at which the front wheels 2 reach the road surface detection position (Lo) according to the vehicle speed V. Then, the adjustment is performed as shown in FIG. Therefore, when the vehicle speed V is low and the front wheels 2 reach the road surface detection position of the road surface sensor 10 relatively late, the damping force switching signal is output late with a correspondingly long delay time ΔT. Therefore, the damping force varying device 30 of the front wheel suspension 5 switches to an appropriate damping force at an optimum timing at which the front wheels 2 reach at least the road surface detection position.

Therefore, as shown in FIG. 7, when the road surface sensor 10 detects the convex portion A, the damping force switching signal of the second mode of FIG. 3 is output to the motors 7 and 7 ', and the damping force of the front wheel suspension 5 is varied. The device 30 switches to that characteristic. Therefore, when the front wheel 2 actually travels on the convex portion A and moves upward, the damping force varying device 30 has a soft damping action on the contracting side and a hard damping action on the extending side. Next, when the rear wheel 3 travels on the convex portion A, the rear wheel suspension 5'has already been switched to the same characteristic, so that the rear wheel suspension 5'is similarly damped and the upward movement of the vehicle body 1 is suppressed.

On the other hand, when the road surface sensor 10 detects the recess B, the damping force switching signal of the first mode in FIG. 3 is output to the motors 7 and 7 ', and the front wheel 2 and the rear wheel 3 actually detect the recess B. When running and moving downward, the front and rear wheel suspensions 5,
In the damping force varying device 30 of 5 ′, the extension side is softly damped on the extension side and the compression side is hard on the damping side, and the downward movement of the vehicle body 1 is suppressed. In this way, the vehicle body 1 of the vehicle is reliably controlled so as to maintain a posture in which there is little vertical movement with respect to the uneven portions A and B of the road surface.

Next, when the vehicle speed is not lower than the set vehicle speed Vs and the delay time cannot be calculated, the control unit 14 fixes the delay time ΔT as ΔT = 0. In this case, the sensor movement amount ΔL is calculated as shown in FIG. 6B by subtracting the shortest sensor front-rear distance Lo from the distance V · Δt that travels according to the vehicle speed V and the delay time Δt of the entire control system. , The movement signal is transmitted to the motor 64 of the sensor actuator 60.
Output to. Therefore, the rail 62 is moved by the pinion 65 of the motor 64 and the rack 62a so that the road surface sensor 10 itself sequentially protrudes horizontally in front of the skirt 54, and the road surface detection position is moved forward of the front wheel 2 by the sensor movement amount ΔL. Become.

In this way, when the front wheels 2 reach the road surface detection position quickly due to the increase of the vehicle speed V, the road surface sensor 10 itself is moved correspondingly to control the road surface detection position to move away from the front of the vehicle body. The delay time Δt of the entire control system is always secured. Therefore, after the delay of the control system, the damping force switching signal corresponding to the road surface information is transmitted to the shock absorbers 20 and 2 of the front and rear wheel suspensions 5 and 5'as described above.
Even if output to 0'motor 7,7 ', at least front wheel 2
The damping force varying device 30 of the front wheel suspension 5 switches to an appropriate damping force at an optimum timing that substantially coincides with when the vehicle reaches the road surface detection position. Therefore, even at medium and high speeds, when the front wheels 2 and the rear wheels 3 reach the uneven portions A and B on the road surface, the front and rear wheel suspensions 5 and 5'attenuate, and the vehicle posture is reliably and stably controlled.

Referring to FIG. 8, as a second embodiment of the present invention, a case where the sensor moves and the angle changes will be described. In this embodiment, in the sensor actuator 60,
The road surface sensor 10 is attached to the tip of the rail 62 so as to change the angle forward with the pin 70 as a fulcrum. Another motor 71 is installed at the tip of the rail 62, and this motor 71 is connected to the road surface sensor 10 via a link 72. Therefore, in this case, the sensor operating device 6
A movement signal is output to the zero motor 64 to move the road surface sensor 10 forward by a predetermined amount, and an angle signal is output to the other motor 71 under the condition that the vehicle speed is higher. Therefore, the angle of the road surface sensor 10 is changed by the motor 71 and the link 72 so that the road surface sensor 10 gradually tilts forward from a state of being directly downward. As a result, at high speeds, the road surface detection position can be moved further forward while suppressing the protrusion of the road surface sensor 10, and the suspension characteristics can be switched at the optimum timing.

Referring to FIG. 9, as a third embodiment of the present invention, a case where the sensor movement and the angle change are simultaneously controlled will be described. In this embodiment, in the sensor actuating device 60, a rail 73 having the road surface sensor 10 is formed in a curved shape and guided so as to be capable of circular arc movement. So in this case,
When a control signal is output and driven to the motor 64 of the sensor operating device 60 at medium and high speeds, the rail 73 is circularly moved, the road surface sensor 10 is controlled to gradually move forward and the forward tilt angle is also increased. It is possible to effectively move the road surface detection position forward by the displacement.

Although the semi-active suspension device has been described as the embodiment of the present invention, the present invention can be applied to the active suspension device and the vehicle behavior characteristic changing means.

[0026]

As described above, according to the present invention,
In the control where the road surface sensor is installed on the vehicle body and the characteristics of the suspension are switched according to the unevenness of the road surface, the road surface sensor is mounted on the lower part of the fender apron in front of the front wheel of the front body by a sensor operating device, so the front of the front wheel is always installed. The road surface can be accurately detected, and the sensor actuating device can be easily assembled. Particularly at medium and high speeds, the sensor actuator moves the road surface sensor forward and backward or changes the angle, and the road surface detection position is controlled to move to the front of the vehicle based on the distance traveled by the vehicle speed and the delay time of the entire control system. It is possible to switch the suspension characteristics at the optimum timing at all times with respect to the system delay, and it is possible to reliably stabilize the vehicle attitude throughout the traveling range.

In the method of moving the road surface sensor of the first embodiment in the horizontal direction, the accuracy of road surface detection is high. In the method of changing the angle of the road surface sensor according to the second embodiment, it is possible to reduce the movement of the road surface sensor and further adapt to a high speed range.
In the method of simultaneously controlling the movement and the angle change of the road surface sensor of the third embodiment, the road surface detection position can be changed efficiently.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an operation control device for a road surface sensor according to the present invention.

FIG. 2 is a cross-sectional view showing a variable damping force type shock absorber.

FIG. 3 is a diagram showing a damping force characteristic of a suspension.

FIG. 4 is a cross-sectional view showing a mounting state and a configuration of a sensor operating device.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is a diagram showing an adjustment state of a delay time and a sensor movement amount.

FIG. 7 is a schematic view showing a concavo-convex state of a road surface.

FIG. 8 is a side view of essential parts showing a second embodiment of the sensor operating device.

FIG. 9 is a side view of essential parts showing a third embodiment of the sensor actuating device.

[Explanation of symbols]

 1 vehicle body 2 front wheel 3 rear wheel 5,5 'suspension 10 road surface sensor 14 control unit 45 front body 46 fender apron 54 skirt 60 sensor actuating device

Claims (3)

[Claims] 1. In a vehicle having suspensions for controlling damping force switching on wheels, a sensor actuating device actuated by an electric signal from a control unit is hung under a fender apron in front of a front wheel of a front body of a vehicle body. The road surface sensor that detects the unevenness of the road surface is attached to this sensor operating device so that it can be projected forward from the position of the shortest front-back distance inside the skirt, and the road surface detection position can be sequentially moved forward. A characteristic road surface sensor operation control device. 2. The sensor actuating device sets a road surface detection position at a position in front of the vehicle body, in which the delay time of the control system is set to zero, especially at middle and high speeds, and the shortest sensor front-back distance is subtracted from the distance traveled by the vehicle speed and the delay time of the entire control system. 2. The operation control device for the road surface sensor according to claim 1, wherein the operation control is performed so as to move the vehicle. 3. The sensor actuating device has a relatively long rail attached to a lower portion of a front apron via a bracket so as to move back and forth linearly or in an arc shape, and a motor driven by an electric signal is connected to the rail. The road surface sensor is fixed or attached to the tip of the rail so as to be fixed or capable of changing the forward inclination angle.
An operation control device for the road surface sensor described.