JPS6336996B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a hydraulic shock absorber that automatically changes the damping characteristics of a suspension of a two-wheeled vehicle depending on its driving conditions.

(Prior Art and Problems to be Solved) It is preferable from the viewpoint of steering stability and ride comfort that the damping characteristics of the hydraulic shock absorber be appropriately changed depending on the speed of the vehicle, road surface conditions, etc. For this reason, the present applicant has developed a hydraulic shock absorber that allows the driver to select and change damping characteristics according to his/her preference, as disclosed in, for example, Japanese Utility Model Application No. 52-85096. However, this method only allows selection of several types of damping characteristics by manual dial operation, and therefore it is not possible to obtain ideal damping characteristics that immediately respond to driving conditions.

The relationship between vehicle speed and required damping force is shown in Figure 3.At low speeds, it is necessary to reduce the damping force with an emphasis on ride comfort, and as the speed increases, it is necessary to increase the damping force with an emphasis on maneuverability. Ideally, the damping force should be proportionally increased as shown in Figure 4 for the live load, and Figure 5 for the suspension spring displacement (determined by road surface conditions, etc.). It is true. However, as mentioned above, manually controlling the damping characteristics cannot respond to constantly changing operating conditions, and even if the optimal damping characteristics can be obtained under certain conditions, there are times when the damping characteristics completely go against the requirements. Cases also arise.

The present invention aims to solve these problems.

(Means for Solving the Problems) In the present invention, a vehicle speed sensor, a load sensor, and a suspension displacement sensor are provided as sensors for detecting the running state of the vehicle, and the output thereof is adjusted according to a calculation constant. An adder is provided to input the output of each sensor, and a reference value setting circuit that can input the damping force adjustment reference signal, a comparison calculation circuit to which the signal from the feedback circuit is input, and a comparison calculation circuit that inputs the adjustment reference signal to the comparison calculation circuit. A changeover switch is provided for selectively switching whether or not to input the output value of the adder in addition to the signal, and the driving amount is controlled based on the output of the comparison calculation circuit, and a signal corresponding to the driving amount is provided. An actuator attached to the feedback circuit is provided, and a hydraulic shock absorber having a damping valve whose set load is variably controlled via the actuator is provided.

(Function) Based on the above configuration, the change characteristic of the set load of the damping valve provided in the hydraulic shock absorber can be arbitrarily selected according to the operation of the changeover switch by the driver. In other words, the first case is when the selector switch is operated so that the output value of the adder is not input to the comparator circuit, and in this case, the remote control based on the driver's judgment is independent of the driving conditions of the vehicle. Therefore, characteristics (fixed characteristics that do not change automatically) are determined. The second case is when the changeover switch is operated so that the output value of the adder is applied to the comparator circuit, and in this case, the output value changes from moment to moment depending on the vehicle speed, loading capacity, and amount of vehicle body displacement. This provides a characteristic in which the set load of the damping valve is automatically controlled optimally in accordance with the required damping force characteristic.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

In FIG. 2, 1 is a cylinder, 2 is a piston rod, and 3 is a rotating rod rotatably inserted into the piston rod 2, which is connected to a motor 6 via a gear 4 and a pinion 5. A motor 6, which is preferably a step motor, a servo motor, or even a rotary solenoid, serves as a drive source for automatically changing the set load of a leaf valve 8, which is a variable damping valve attached to a piston 7, and is controlled by a control circuit to be described later. According to the input, the rotating rod 3 is rotated to move the sliding tube 9 up and down, and the pin 1
Spring 11 interposed between 0 and leaf valve 8
The damping characteristics are continuously changed by changing the compressive force of the damper.

In the control circuit shown in FIG. 1, 14 is a vehicle speed sensor that detects the vehicle running speed, 15 is a load sensor that detects the loaded weight, 16 is a displacement sensor that detects the amount of suspension displacement during cornering, etc., 17, 18, Reference numeral 19 denotes a gain adjuster for each sensor, which adjusts each proportional constant depending on the input value and the required attenuation characteristic. 20 is a low-pass filter that removes high frequency components of the displacement sensor 16; 21 is an adder; 22 is a reference value setting circuit that can set the damping force characteristics according to the driver's preference; this set value and the output of the adder 21 are The signal is sent to the comparison calculation circuit 23. If the motor 6 is a pulse motor, the rotating rod 3 will rotate by a predetermined angle based on the output pulse obtained by converting the output from the comparison calculation circuit 23 into a pulse. 24 is a feedback circuit, 25 is an automatic/manual changeover switch, and 26 is an amplifier.

Next, it will be explained in more detail, including its effect. First, the case of setting the damping force by manual operation will be described. The switch 25 is turned off and the output of the reference value setting circuit 22 is set to a desired setting value by operating a dial or the like. When the motor 6 drives the rotary rod 3 according to this set value, the compression force (set load) of the spring 11 on the leaf valve 8 changes. For example, if the compression force increases, the leaf valve 8
The flow path resistance increases, and the damping force increases. Therefore, when driving at high speeds, carrying high loads, or even cornering frequently, the output of the reference value setting circuit 22 is increased to predict this in advance and set the characteristic curve of the damping force relative to the piston speed to a third value. Shift from the figure to the upper part of FIG. Conversely, at low speeds or in poor road conditions, the damping characteristic curve is shifted downward to provide a soft and comfortable ride. In addition, motor 6
Since the amount of rotation of the motor 6 is input to the comparison calculation circuit 23 via the feedback circuit 24 as a signal corresponding to the amount of drive, the drive of the motor 6 is appropriately corrected.

Next, a case will be described in which the damping force is automatically controlled. When the changeover switch 25 is turned on, the signals from the vehicle speed sensor 14, load sensor 15, and displacement sensor 16 are transferred to each gain adjuster 17, 1.
8 and 19, the adder 21
These signals are added and subtracted as a determination signal of the overall operating state at that time, and then provided to the comparison arithmetic circuit 23. The output value from this adder 21 is added to or subtracted from the set value of the reference value setting circuit 22 (in this case, set to the output value that guarantees the minimum damping force characteristic), and the optimum damping characteristic corresponding to the driving situation is determined. obtained in real time. Therefore, the damping force characteristics shown in Figures 3 to 5 are automatically obtained. For example, when driving with a standard value suitable for a paved road, when suddenly driving on a rough road. Even in the past, damping characteristics suitable for driving on rough roads are automatically obtained, allowing continued comfortable driving.
Similarly, do you suddenly need to increase your speed?
Even if the vehicle encounters a sharp curve, each sensor can detect this change and increase the damping force to prevent the vehicle from falling over. It goes without saying that the present invention can also be applied to structures and characteristics of damping valves other than those disclosed in this embodiment.

(Effects of the Invention) As described above, the present invention provides a vehicle speed sensor, a load capacity sensor, and a suspension displacement sensor as sensors for detecting the running state of a vehicle, and each sensor whose output is adjusted according to a calculation constant. An adder is provided to input the output of the sensor, and a reference value setting circuit to which a damping force adjustment reference value signal can be input, and a comparison calculation circuit to which the signal from the feedback circuit is input are provided. The output value of the device can be selectively inputted via a changeover switch, and an actuator is provided whose drive amount is controlled based on the output of the comparator circuit, and the damping force is variably controlled via this actuator. Equipped with a hydraulic shock absorber with a damping valve, it is possible to automatically provide the optimal damping force characteristics at each moment in response to the ever-changing driving conditions of the vehicle. This not only improves handling stability, but also improves ride comfort. In addition, the damping force characteristics can be changed arbitrarily even while driving based on the driver's judgment as necessary, so for example when the driver predicts a change in driving conditions, It is possible to switch to the optimal damping force characteristic in advance even before the sensor that detects the condition actually detects the condition.
Another effect is that the practicality as a shock absorbing device is significantly improved.

The control system of the present invention is configured to open-loop control the spring set load of the shock absorber damping valve based on the vehicle speed, load capacity, and set values determined by the driver's will, and the set load is applied to this. Since a function is provided to correct and control the actuator driving amount by feedback control, the circuit configuration is simple and the damping force characteristics can be controlled with good response and accuracy.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention: Fig. 1 is a block diagram of the control circuit, Fig. 2 is a partially cutaway front view of the hydraulic shock absorber, and Fig. 3 shows changes in vehicle speed and required damping accordingly. Figure 4 is an explanatory diagram showing the load and the corresponding required damping characteristics. Figure 5 is an explanatory diagram showing the displacement (settlement amount) of the spring and the required damping characteristics corresponding to it. be. 3...Rotating rod, 6...Motor, 8...Leaf valve (damping valve), 14...Vehicle speed sensor, 15
...Loading capacity sensor, 16...Displacement sensor, 21...
. . . Adder, 22 . . . Reference value setting circuit, 23 . . . Comparison calculation circuit.

Claims (1)

[Claims] 1. A vehicle speed sensor, a load sensor, and a suspension displacement sensor are provided as sensors for detecting the running state of the vehicle, and an adder is provided to input the output of each sensor whose output is adjusted according to a calculation constant. A reference value setting circuit into which a damping force adjustment reference signal can be input; a comparison calculation circuit into which a signal from the feedback circuit is input; and whether the output value of the adder is input to the comparison calculation circuit in addition to the adjustment reference signal. and an actuator whose drive amount is controlled based on the output of the comparison arithmetic circuit, and an output signal corresponding to the drive amount of the actuator is provided to the feedback circuit. A damping force adjustable hydraulic shock absorber comprising a hydraulic shock absorber having a damping valve in which the set load of a damping force generating valve spring is variably controlled via the actuator.