JPH0126886B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a shock absorber control device, and more particularly to a shock absorber control device that prevents a sudden nose-up when a vehicle starts or accelerates while running at low speed.

[Prior Art and Problems to be Solved by the Invention] Conventionally, various safety measures have been taken with respect to nose-up during starting and acceleration from the viewpoint of safety management in automobile operation.

For example, by setting the damping force of the shock absorber to be high in advance, in other words, by suppressing the movement of the suspension spring and reducing the degree of buffering,
There are ways to prevent sudden nose rise. However, as a result, the vibration of the vehicle body became intense, and ride comfort was ignored, causing discomfort to the occupants.

In order to solve this conflicting problem of nose up and ride comfort, a system was devised that uses a shock absorber with variable damping force and adjusts the damping force manually or automatically.
In automatic systems, it is troublesome to make adjustments one by one, and an adjustment error can have the opposite effect.In automatic systems, a vehicle speed signal from a vehicle speed sensor often used for automatic drive control is used, When the vehicle speed exceeds this level, the shock absorber's damping force is increased, and when it falls below that level, the shock absorber's damping force is immediately reduced. If the axle rotation is too slow, the pulse interval will be too long and accurate measurement will not be possible.Furthermore, it will take a long time to obtain a sufficient number of pulses to measure the vehicle speed. Velocity and acceleration detection was difficult or slow. Furthermore, when using a G sensor that digitally detects changes in gravity due to changes in speed in the open/closed state of a switch, it may be difficult to distinguish them from vibrations of the vehicle. Due to these problems, it is not easy to prevent nose-up during sudden starts and accelerations in all vehicle speed ranges of real vehicles, especially in low speed ranges, and the conditions under which this function can be demonstrated are limited. It was hot.

The present invention determines when the vehicle is running at low speed and predicts or estimates the tilt of the vehicle based on the opening/closing of the idling switch or the opening/closing state of the throttle valve. This also prevents the occurrence of problems, thereby realizing even greater vehicle running stability, safety, and driving comfort.

[Means for Solving the Problems] The gist of the present invention is to provide a driving state detecting means comprising either a throttle position sensor or an idling switch and a vehicle speed sensor; low speed determination means for determining whether the vehicle speed is less than a reference value; and when the low speed determination means determines that the vehicle speed is less than the vehicle speed reference value, the vehicle speed is determined based on a signal from the throttle position sensor or the idling switch. acceleration determination means for determining whether the vehicle is in a state of acceleration; and a shock provided on the vehicle to suppress vehicle nose up when the acceleration determination means determines that the vehicle is in a state of acceleration. A shock absorber control device includes: a control means for outputting a signal to an absorber;

[Function] In the low speed range, it is difficult for the vehicle speed sensor to accurately obtain measured values and its responsiveness is low, so its signal is unsuitable as a parameter for rapid control of the shock absorber. Therefore, if the vehicle speed sensor outputs a signal indicating that the vehicle speed is less than the predetermined vehicle speed reference value, the low speed determining means first determines this state. If this determination has been made, the acceleration determining means determines whether the vehicle speed is in an accelerated state based on a signal from the throttle position sensor or the idling switch that is not affected by the vehicle speed. Then, the control means outputs a signal to a shock absorber provided in the vehicle in order to suppress vehicle nose up during acceleration, based on the determination of the acceleration state by the acceleration determination means.

In particular, the signal from the throttle position sensor or idle switch is accurate because it captures the point in time before the vehicle accelerates, i.e., when the engine output begins to rise. A signal can be output to the shock absorber and sufficient responsiveness can be obtained.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the shock absorber control device of the present invention. Here 1
is a control device including a microcomputer, and a throttle position sensor 2, a stop switch 3, and a vehicle speed sensor 4 are connected to its input side via buffers 5, 6, and 7, respectively, and each axle and chassis are connected to its output side. Drive parts 8b, 9b, 10b, 1 such as solenoids or motors for adjusting the damping force of the shock absorber disposed between the
1b are drive circuits 8a, 9a, 10a, 11a, respectively.
connected via.

Here, the throttle position sensor 2
For example, a device is used that detects the opening degree of a throttle valve of a carburetor and converts it into an electric signal in conjunction with an accelerator pedal.

Further, the vehicle speed sensor 4 generates a pulse signal with a frequency proportional to the rotational speed of the axle by repeating opening and closing of the reed switch using, for example, a fixed reed switch on the vehicle body side and magnets arranged at equal angular intervals on the axle side. There are also other methods that generate pulses in a coil combined with a rotating magnet, or devices that convert light pulses into electrical pulse signals by placing reflective markers on the axle at equal angular intervals. If it is also used for drive control, there is no need to install a special sensor.

With this configuration, the control device 1 receives signals from the throttle position sensor 2, stop switch 3, or vehicle speed sensor 4 via the input buffers 5, 6, and 7, performs calculations or judgments based on the signals, and uses the results as Therefore, the drive circuits 8a, 9a, 10
Shock absorber drive unit 8 via a, 11a
b, 9b, 10b, and 11b to adjust the damping force of the shock absorber to prevent sudden nose up and pitching.

FIG. 2 is a flowchart showing an embodiment of the processing operation path of the shock absorber control device of the embodiment described above.

Here, 101 represents a step for initializing the contents of the random access memory in which various registers, flags, and various variables of the microcomputer in the control device 1 are set.

102 represents a step for calculating the vehicle speed, and by executing a vehicle speed interrupt routine (not shown), for example, the i-th vehicle speed pulse from the vehicle speed sensor and the i-th vehicle speed pulse are calculated.
Vehicle speed data V proportional to the magnitude of the vehicle speed is calculated from the ratio of the vehicle travel distance corresponding to four pulses, which is the difference from the +4th vehicle speed pulse, and the number of clocks during that time.

Reference numeral 103 represents a step for calculating acceleration, and from the temporal change of the vehicle speed data V obtained in the speed calculation step 102, for example, the vehicle speed V _i calculated at the i-th to i+4th vehicle speed pulse and the i-th to i+1 to i+
Calculate acceleration data V which is proportional to the magnitude of acceleration from the difference in vehicle speed V _i+1 calculated using the fifth vehicle speed pulse and the ratio of the time difference between the i-th vehicle speed pulse and the i+1-th vehicle speed pulse. .

104 represents a step for determining the value of vehicle speed V;
The vehicle speed V obtained in step 102 is a predetermined reference value.
Determine whether or not V is greater than or equal to _N , and select “YES” (affirmative)
If so, the process advances to step 105, and if "NO" (negative), the process advances to step 106.

105 represents a step for determining the value of acceleration V〓, and it is determined whether the acceleration V〓 obtained in step 103 is greater than or equal to a predetermined reference value _V〓A , and if “YES”, the process proceeds to step 113. , if “NO”, step
Processing moves to 108.

106 indicates whether or not the opening degree of the throttle valve is greater than or equal to a predetermined reference value _θN , for example, 4 depending on the opening degree.
The throttle valve opening status is determined in 16 ways based on the signal from the throttle position sensor that emits a bit signal, and if YES, step 107 is performed.
If the answer is "NO", the process moves to step 108.

Reference numeral 107 represents a step for determining whether or not the brake stop switch is opened. If "YES", that is, the brake stop switch is opened, the process proceeds to step 113, and if "NO", that is, the brake stop switch is closed, the process proceeds to step 108.

108 represents a step for determining whether or not the shock absorber is in a high damping force state, for example, based on the value of a flag; if "YES", go to step 109; "NO"
If so, the process moves to step 112.

109 is the shock absorber's high damping force retention time
Represents a step of determining whether or not the counter is measuring TE using a flag indicating that the counter is measuring time.
If "YES", the process moves to step 111; if "NO", the process moves to step 110.

110 represents the step at which the counter starts counting time.

111 indicates whether the counter has timed the time TE or not.
For example, it indicates a step to check the flag and determine the progress of TE, and if "YES", the step is
If the answer is "NO", the process moves to step 116.

112 is the shock absorber drive circuit 8a, 9
By inputting signals from the control device 1 to a, 10a, 11a, the drive units 8b, 9b, 10b, 11
b represents a step in which the shock absorber is activated to change the damping force state to a low damping force state or to maintain the shock absorber in a low damping force state.

Similar to step 109, 113 represents a step for determining whether or not the counter is measuring the holding time TE using a flag; if "YES", go to step 114;
If "NO", the process moves to step 115.

114 represents a step in which the counter stops counting time.

115 resets the counter to its initial state.
This represents the step to prepare for starting TE timing.

116 is the opposite to 112, by inputting a signal from the control device 1 to the shock absorber drive circuits 8a, 9a, 10a, 11a, the drive units 8b, 9b,
10b and 11b act to change the shock absorber to a high damping force state or to maintain it in a high damping force state.

Next, the processing operation will be explained with reference to the flowchart configured as described above.

The device of the embodiment is started by turning on the shock absorber control device.
In this case, in consideration of the effort required to turn on the switch, the switch of this device may be linked with the ignition key to start the device at the same time as the engine starts.

First, in step 101, the microcomputer in the control device 1 is initialized.

When the vehicle is idling and is not moving,
The vehicle speed sensor 4 does not emit a pulse signal and is in step mode.
The vehicle speed V and acceleration V〓 of 102 and 103 are not calculated,
Since the initial setting value 0 remains, and the opening degree θ of the throttle valve is usually less than the reference value θ _N , in this state, the process is performed in steps 102, 103, 104, 106, and The process returns to step 102 via steps 108 and 112, and the damping force of the shock absorber is kept low by the processing in step 112. The above route is repeated as long as this state continues.

If, by any chance, the opening degree θ of the throttle valve becomes greater than θ _N during idling, the process will be carried out in steps 102, 103, 104, 106, 107, 113,
The route returns to step 102 via steps 115 and 116, and the damping force of the shock absorber is increased by the processing in step 116, but in such a case, the problem of discomfort due to vibration occurs because the vehicle is not running. Never.

Next, when the vehicle starts running, the vehicle speed sensor 2 starts to transmit a pulse signal proportional to the rotation speed of the axle in conjunction with the rotation of the axle.

Here, when the vehicle starts slowly, the vehicle speed V and the throttle valve opening θ are their reference values V _N and θ _N , respectively.
In the state where the
Steps through 102, 103, 104, 106, 108 and 112
Change the route back to 102. Here, since the shock absorber is not yet in a high damping force state at step 108, the process moves directly to step 112 and the low damping force state is maintained.

Next, although the vehicle speed V is less than the reference value _VN , in order to perform rapid acceleration, the accelerator is strongly depressed and the opening degree θ of the throttle valve is made to be equal to or greater than the reference value _θN . 103, 104,
Step 102 via 106, 107, 113, 115, and 116
Change the route back. Step here
In step 115, the high damping force holding time counter is set to an initial value, and in step 116, the shock absorber changes from low damping force to high damping force, thereby preventing sudden nose up.

In such a low vehicle speed state where the vehicle speed V is below the reference value _VN , the vehicle speed sensor 4 cannot output a sufficient number of pulses at sufficiently short intervals. For this reason, it is not preferable in terms of accuracy and responsiveness to use the detected value of the vehicle speed sensor 4 or the acceleration obtained from that value as it is. Therefore, in that case, the acceleration is predicted based on the opening degree θ of the throttle valve. That is, when θ≧θN, it is predicted that the acceleration will be large enough to cause nose up, so the shock absorber is switched to a high damping force.

Next, when the vehicle speed reaches a high speed equal to or higher than the reference value V _N and continues to rapidly accelerate, the process proceeds to steps 102, 103, 104, 105, 113, 115 and 116.
The route then returns to step 102. Here, the acceleration is determined in step 105 based on the signal from the vehicle speed sensor 4, and then the process moves to step 116, and the high damping force state of the shock absorber continues through the process of step 116.

Next, in the state immediately after the vehicle speed is equal to or higher than the vehicle speed reference value _VN and the acceleration becomes less than _V〓A , the processing is performed in steps 102, 103, 104, 105, 108, 109
The route changes through steps 110, 111 and 116 and returns to step 102. Here, in step 110, a counter starts counting the high damping force holding time TE of the shock absorber. and retention time
Since TE has not elapsed yet, processing continues at step
The process moves from step 111 to step 116, and the shock absorber continues to maintain the high damping force. The high damping force continues until TE elapses, after which step 102
103, 104, 105, 108, 109, 111 and 112 to return to step 102.
Only by processing 112 can the shock absorber return to its low damping force state.

On the other hand, in a low vehicle speed state below the reference value V _N ,
The throttle valve opening θ changes to less than θ _N from a state of rapid acceleration, such as when the throttle valve opening is above its reference value θ _N and the brake is not depressed and the stop switch is released. In the state immediately after, or even in the state immediately after the stop switch is closed, the process continues in step 102.
Path or step returning to step 102 via steps 103, 104, 106, 108, 109, 110, 111 and 116
102, 103, 104, 106, 107, 108, 109, 110, 111
The high damping force of the shock absorber is maintained while the high damping force holding time TE is being counted by returning to step 102 through steps 116 and 116, and then steps 102, 103, 104,
A route returning to step 102 via steps 106, 108, 109, 111 and 112 or steps 102, 103, 104,
Steps through 106, 107, 108, 109, 111 and 112
Step by moving the route back to 102
The shock absorber returns to the low damping force state for the first time in process 112.

The above processing operation will be explained with reference to FIG.

The upper graph in FIG. 3 represents changes in acceleration, with the vertical axis representing acceleration V〓 and the horizontal axis representing time. The lower graph in FIG. 3 shows the time in which the shock absorber is in a high damping force state in a band shape over time.

Here, time T1 is the time when the acceleration V〓 indicated in the determination at step 105 transitions from less than the reference value _V〓A to more than _V〓A , and from this point on, the shock absorber enters the high damping force state H1.

Time T2 is the point in time when the acceleration V〓 transitions from the reference value V〓 _A or more to less than V〓 _A. Since the high damping force holding time TE of the shock absorber starts from this point, the shock absorber does not immediately enter the low damping force state but continues to maintain the high damping force state H2. Then, at T2 + TE, when TE has elapsed from T2, the damping force returns to the low damping force state.

However, as mentioned above, the vehicle speed V decreases before TE elapses.
If the acceleration V〓 reaches the standard value _V〓A again while the acceleration V〓 reaches the standard value _V〓A again, the processing of the control device in FIG.
, and then returns to step 102. Here, in step 114, the TE timing that has already started is stopped, and the high damping force state of the shock absorber is extended. Then, when the acceleration V〓 becomes less than the reference value V〓 _A , the process proceeds to steps 102, 103, 104,
The route changes through steps 105, 108, 109, 110, 111 and 116 and returns to step 102. put it here,
The counter starts counting again at step 110.
From this point until after the TE has elapsed, the process proceeds along a route that returns to step 102 via steps 102, 103, 104, 105, 108, 109, 111 and 112. Here, by going through the process of step 112, the shock absorber returns to the low damping force state.

To explain this with reference to FIG. 3, time T3 is the point in time when the acceleration V〓 transitions from less than the reference value _V〓A to a state equal to or higher than the reference value _V〓A . From this point on, the shock absorber enters the high damping force state H3. Time T4 is acceleration V〓
This is the point in time when the voltage transitions from the reference value V〓 _A or more to the state below V〓 _A. From this point on, the counter starts counting time in the same manner as described above, and the high damping force state H4 continues. However, if the acceleration V〓 transitions from less than the reference value V〓 _A to more than V〓 _A at time T5 before the TE elapses, the TE timing will be stopped at that point and the TE will be returned to its initial state. Even when T4+TE (not shown) is reached, the shock absorber remains in the high damping force state H5 or H6. Then, at time T6 when the acceleration V〓 transitions from the reference value V〓 _or more to the state less than _V〓A , the measurement of the holding time TE of the high damping force state H6 is started again from the beginning. and the point in time
At T6+TE, the shock absorber returns to low damping force. In the end, the high damping force state of the shock absorber continues to be maintained from time T3 to time T6+TE. And time T6+TE
If the acceleration V〓 again exceeds the reference value V〓 _A before the elapse of time, the high damping force state of the shock absorber will be further extended, and if the same situation repeats, the high damping force state will continue to be maintained for a long time. become.

Similar to the process based on the determination of the acceleration V〓 described above, even when the vehicle speed V is less than the reference value _VN , the determinations in steps 106 and 107 are both "YES".
The counter starts measuring the high damping force holding time TE of the shock absorber after the transition from the state where one of them is "NO" to the state where one of them is "NO". When the throttle valve opening θ transitions to the reference value θ _N or more while the stop switch is open, or when the stop switch transitions to the open state while the throttle valve opening θ exceeds θ _N. Time points T2, T4, and T6 correspond to the time points when the opening degree θ of the throttle valve transitions to less than the reference value θ _N or the time points when the stop switch transitions to the closed state, and the same processing and effects are applied. to do. However, a vehicle can only be accelerated when the driver depresses the throttle pedal and opens the throttle valve, which increases the output torque of the engine rotation and further transmits the rotational driving force to the wheels. Therefore, at the time T1 when the opening degree θ of the throttle valve transitions to a state equal to or greater than the reference value θN,
T3 and T5 are actually predictions and predictions made before the vehicle accelerates.
This is the estimated timing, and is immediately before the timing at which nose-up occurs. Therefore, if the opening degree θ of the throttle valve is used, the response is better than that of the vehicle speed sensor, so nose-up can be prevented.

Furthermore, the same processing and effect can be obtained not only when the acceleration conditions or the throttle valve opening and stop switch conditions operate separately, but also when they are combined.

In this embodiment, an idling switch may be used in place of the throttle position sensor 2 to achieve the same purpose. The idling switch is a switch that detects whether the engine is idling or not, and is built into the accelerator pedal. When the engine is idling, the switch is closed. In this case, step 106 or 206 for determining whether the opening degree θ of the throttle valve is equal to or greater than the reference value θ _N corresponds to determining whether the idling switch is open or not. Of course, the responsiveness is the same as in the case of the opening degree θ of the throttle valve.

As a result, by providing the high damping force holding time TE, in addition to being able to prevent the sudden nose-up which is the object of the present invention, when setting the high damping force only at accelerations above a certain level, It is possible to prevent pitting that can suddenly occur when the damping force changes from high damping force to low damping force.

Even if the holding time TE is 0, rapid nose-up can be prevented, but in order to further prevent the pitching described above, an appropriate time can be set, and generally several seconds is appropriate.

Another effect is that the damping force of the shock absorber is adjusted according to the calculated acceleration in regions where the vehicle speed is high, but in regions where the vehicle speed is slow, either the opening/closing of the idling switch or the opening of the throttle valve and the stop switch are adjusted. By adjusting the damping force depending on the opening/closing state of the vehicle, it compensates for the drawbacks of vehicle speed sensors that are difficult to detect or have a delay in detecting vehicle speed from a stopped state to a low vehicle speed range, and completely eliminates nose-up and pitching at low speeds. It is preventable.

The reference value V _N of the vehicle speed V changes depending on the performance of the vehicle speed sensor, but generally it is converted to the actual vehicle speed.
A value of 10km or less will be adopted.

In addition, the reference value V〓 _A of the acceleration V〓 is set in consideration of safety,
It is preferable to set it to about 0.15G in terms of actual deceleration.

As a more basic embodiment of the present invention, when the retention time TE is set to 0, processing according to the flowchart shown in FIG. 4 may be used.

In this flowchart, if the vehicle speed V is greater than or equal to the reference value V _N and the acceleration V is less than the reference value V _A , or if the vehicle speed V is less than V _N and the throttle valve opening θ is
is less than the reference value θ _N or the stop switch is closed, step 208 is executed and the shock absorber is in a low damping force state.

On the other hand, when the vehicle speed V is greater than or equal to V _N and the acceleration V〓 is V〓 _A
If the vehicle speed V is less than _VN , the throttle valve opening θ is more than _θN , and the stop switch is open, step 209 will be executed, and the shock absorber will have high damping. It becomes a power state. In this case, as in the previous embodiment, an idling switch can be used instead of the throttle position sensor.

However, in this embodiment, if next the vehicle speed V is equal to or higher than the reference value V _N and the acceleration V〓 transitions from the reference value V〓 _A or higher to less than V〓 _A , or when the vehicle speed V
The throttle valve opening θ is less than θ _N , the throttle valve opening θ is greater than the reference value θ _N , and the stop switch is open, and the throttle valve opening θ is less than θ _N or the stop switch is closed. If the
208 and returns to the low damping force state.

In each of the above embodiments, the control device 1 corresponds to the low speed determination means, the acceleration determination means, and the control means, the processing in steps 104 and 204 corresponds to the processing as the low speed determination means, and the processing in steps 106 and 206 corresponds to the acceleration determination means. This corresponds to the processing as a determining means, and the processing in steps 116 and 209 corresponds to the processing as a control means.

FIG. 5 shows a sectional view of an embodiment of a shock absorber applicable to the present invention.

Here, the shock absorber consists of an upper movable part 50 and a lower movable part 51, and the upper movable part 5
0 is fixed to the upper mount 52 at its upper end by welding or the like, while the lower movable part 51 is similarly fixed to the lower mount 53 at its lower end. The upper movable part 50 and the lower movable part 51 reciprocate in opposite vertical directions in response to changes in the load applied between the upper mount part 52 and the lower mount part 53 due to vibrations generated by the vehicle, thereby absorbing the shock. perform an action.

The upper movable part 50 includes a dust cover 54 and an upper lid 56 that covers the upper opening of the dust cover 54 and is fixed to the upper mount 52.
are fixed by welding etc. A flow control valve drive unit 60 is disposed in a recess 59 provided at the upper end of the piston rod 58, and a connecting rod 62 is slidably inserted in a central vertical hole 61 of the piston rod 58. A piston portion 63 is attached to the lower end of the piston rod 58. The flow control valve drive unit 60 is the drive unit 8b, 9b, 10 in FIG.
b or 11b, a ring-shaped core 66 fixed to the connecting rod 62 by an outer stepped portion 64 of the connecting rod 62 and a screw 65, and a piston rod 5.
8 is fixed to the inner peripheral surface of the recess 59 by welding or the like,
In addition, there is a non-magnetic and insulating ring-shaped coil guide 67 that allows the ring-shaped core 66 to slide in the vertical direction, and a ring-shaped coil guide 67 that is embedded in the coil guide 67 and hermetically sealed in the dust cover 54. A coil 68 is attached and electrically connected to the drive circuit 8a, 9a, 10a or 11a shown in FIG. 1, and a spring is inserted between the lower surface of the core 66 and the bottom surface of the recess 59 of the piston rod 58. 69, and a non-magnetic stopper 70 that limits the downward movement of the core 66.

Further, a valve body 72 that is slidable on the inner circumferential surface of the piston 71 is integrally formed at the lower part of the connecting rod 62. Further, an oil port 73 is penetrated through the longitudinal center portion of the connecting rod 62, and the oil port 73 is connected to a third oil chamber 74 formed by the upper cover 56, the coil guide 67, the core 66, etc., and the lower movable portion. 51 and the first oil chamber 75 .
Further, the communication hole 76 communicates the oil port 73 and the fourth oil chamber 77. Further, the piston portion 63 slides in the cylinder 55 of the lower movable portion 51 in the vertical direction. The piston 71 is provided with an oil passage hole 87 that communicates between the first oil chamber 75 and the valve chamber 78 of the lower movable part 51 and an oil passage hole 80 that communicates between the second oil chamber 79 and the valve chamber 78. . Further, a spring 81 is inserted into the valve chamber 78, and the spring 81 presses the valve body 72 downward when the flow rate control valve drive unit 60 is not energized, that is, in the normal state, and connects the oil passage hole 87 and the valve chamber. 78 in communication. Further, the valve body 72 is provided with a communication hole 82 that connects the valve chamber 78 and the first oil chamber 75 to each other.

On the other hand, the lower movable part 51 includes a cylinder 55 whose upper part is inserted into the dust cover 54, and a cylinder 55 whose upper part is inserted into the dust cover 54.
a lower lid 57 that covers the lower end opening of the cylinder 55 and is fixed to the lower mount 53; a rod guide 84 that has a piston rod guide hole 83 in the center and is fixed to the inner peripheral surface of the upper end of the cylinder 55; , and a free piston 85 inserted into the lower inner peripheral surface of the cylinder 55.

Then, the inner circumferential surface of the cylinder 55 and the piston portion 6
A first oil chamber 75 is formed by the lower surface of the cylinder 55 and the upper surface of the free piston 85, and the inner peripheral surface of the cylinder 55, the upper surface of the piston portion 63, and the piston rod 58
A second oil chamber 79 is formed by the outer circumferential surface of the rod guide 84 and the lower surface of the rod guide 84, and the lower cover 57 and the cylinder 55
A high pressure gas chamber 86 is formed by the inner peripheral surface of the free piston 85 and the lower surface of the free piston 85 .

The operation of the shock absorber constructed as described above will be explained below.

In normal running conditions, the spring 81 in the valve chamber 78 continues to press the valve body 72 of the connecting rod 62 downward, and the piston part 63 is maintained in the state shown in the figure, so that the valve chamber 78 and the first oil chamber 75 are maintained in communication with each other through the oil passage hole 87.
Therefore, the first oil chamber 75 and the second oil chamber 79
are maintained in communication with each other through the oil passage hole 87, the valve chamber 78, and the oil passage hole 80.

Therefore, when compressive force is applied to the shock absorber due to pitching of the vehicle, the first oil chamber 7
5 receives a pressing force from the piston part 63, and the oil in the first oil chamber 75 flows into the second oil chamber 79 through the oil passage hole 87, the valve chamber 78, and the oil passage hole 80, while the shock absorber When a tensile force is applied to the piston part 63, the second oil chamber 79 receives a pressing force from the piston part 63, and the oil in the second oil chamber 79 flows through the oil passage hole 80 and the valve chamber 78.
and the first oil chamber 75 via the oil passage hole 87.
flow inside. Therefore, the shock absorber is in a low damping force state.

On the other hand, when the acceleration of the vehicle exceeds a predetermined level, the coil 68 of the flow control valve drive unit 60 is
A current is supplied to generate a magnetic force, the core 66 receives this magnetic force, the core 66 and the connecting rod 62 move upward, and the valve body 72 closes the oil passage hole 87. Therefore, the oil passage hole 87 and the valve chamber 78
Since the flow path between the first oil chamber 75 and the second oil chamber 79 is blocked, compared to the communication hole 87,
Only the passage 82 having a small area communicates, the flow of oil decreases, and the pressure in the first oil chamber 75 increases rapidly. This state is maintained until the current supply to the coil 68 is cut off, and during this time the first
The pressure in the oil chamber 75 is maintained at a high level value.
In other words, the damping force of the shock absorber is higher than that under normal driving conditions as described above.

Thereafter, when the current supply to the coil 68 is stopped, the magnetic force disappears, and the core 66 and the connecting rod 62 move downward with respect to the piston rod 58, returning to the original state as shown in FIG. Therefore, the shock absorber returns to the low damping force state.

In addition to the above configuration, the oil passage hole 87 is
The rest position of the valve body 72 can be adjusted by adjusting the vertical sliding of the valve body 72 by the amount of current supplied to the coil 68 or the amount of rotation of the motor to match the number of oil passage holes. By setting several levels, it becomes possible to divide the damping force of the shock absorber into several levels and select the damping force. Furthermore, the throttle position sensor or stop switch may also be provided with stages, and the rest position of the valve body 72 may be set in accordance with the stages when the vehicle speed is low.

Although it is effective to control only the front and rear wheels of the four shock absorbers, it is more effective to control the four shock absorbers at the same time.

[Effects of the Invention] As explained above, according to the shock absorber control device of the present invention, at low vehicle speeds, acceleration can be accurately predicted and estimated using the throttle position sensor or idling switch before acceleration occurs, and the acceleration The damping force of the shock absorber can be selected according to the Therefore, when the vehicle is running at low speeds, the acceleration state can be detected easily and with good response, so the damping force can be controlled accurately even at low speeds, preventing the vehicle's nose from rising rapidly in the low speed range, and helping the driver. The system maintains the field of view and maintains the direction of the optical axis of the headlight at night, contributing to the safety of the occupants.

[Brief explanation of drawings]

FIG. 1 shows the configuration of an embodiment of the shock absorber control device according to the present invention, FIG. 2 is a flowchart explaining its processing operation, FIG. 3 is a graph showing the shock absorber operation timing by this device, and FIG.
The figure is a flowchart explaining other processing operations of the present apparatus, and FIG. 5 is a longitudinal sectional view of one embodiment of a shock absorber combined with the present apparatus. DESCRIPTION OF SYMBOLS 1... Control device, 2... Throttle position sensor, 3... Stop switch, 4... Vehicle speed sensor, 8a, 9a, 10a, 11a,... Drive circuit, 8b, 9b, 10b, 11b,... Drive Department,
60...Flow control valve drive unit, 72...Valve body.

Claims (1)

[Scope of Claims] 1. A driving state detection means comprising either a throttle position sensor or an idling switch and a vehicle speed sensor, and a low speed sensor for determining whether a vehicle speed signal from the vehicle speed sensor is less than a predetermined vehicle speed reference value. determining means; when the low speed determining means determines that the vehicle speed is less than the vehicle speed reference value, determining whether the vehicle is in a state of acceleration based on a signal from the throttle position sensor or the idling switch; and a control means for outputting a signal to a shock absorber provided on the vehicle to suppress vehicle nose up when the acceleration determining means determines that the vehicle is being accelerated. Shock absorber control device.