JPH057505U - Suspension - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to obtain a suspension having a structure capable of suppressing pitching particularly in a vibration mode. [Constitution] In the present invention, the control valve 5 is connected to the output side,
The vehicle speed sensor 10 and the steering angle sensor 1 are provided on the input side.
1, a vehicle height sensor 12 arranged on the front wheel side and a vehicle height sensor 12 arranged on the rear wheel side, and a road surface detecting means 13 are respectively connected to the control portion 9. The road surface detecting means 13 is provided when the vehicle travels straight ahead. Based on the signal from the vehicle height sensor 12 and the signal from the vehicle height sensor 12, unevenness on the road surface is detected, and at a time when the difference in vehicle height between the front wheel side and the rear wheel side reaches a predetermined value or more. Is characterized in that the position of the control valve 9 is set so that the difference in vehicle height is eliminated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

  The present invention relates to a suspension, and more particularly, to a suspension spring constant. It relates to a variable number structure.

[0002]

[Prior art]

  As is well known, in the case of automobile suspensions, the There is a structure that can change the damping force and spring constant of the Quabzobar.   That is, as a structure in which the spring constant is changed, for example, a shock absorber Two air chambers, large and small, are provided in the upper support part, and two air chambers of large and small are placed between these air chambers. A structure in which the flow passage area of this air passage is changed by connecting the passages (for example, For example, published on June 5, 1986, Grand Prix Publishing Co., Ltd. ), And the structure for changing the damping force is the shock absorber described above. If the flow path setting of the orifice provided on the piston of the Specifically, there is a structure (same as above) that opens and closes the orifice.

[0003]

[Problems to be solved by the device]

  By the way, in the above-mentioned suspension, for example, the wheel base is short. In the case of a bad vehicle, when the unevenness of the road surface is repeated, a wavy vibration mode, A so-called pitching moment may be generated to deteriorate the riding comfort.   That is, the above-mentioned phenomenon is caused by the spring constant and the bar around a certain position in FIG. The elastic center, which is the point where the reaction force and the moment balance, is affected by the road surface condition. It changes depending on the behavior of the vehicle body, and more specifically, shocks at the front and rear wheels when passing through unevenness on the road surface Due to the different reaction force against the absorber, the elastic center moves away from the center of gravity of the vehicle body. If it does, the vibration of the pitching mode, which swings in the front-back direction, is likely to occur, It will make the ground worse.   This pitching mode also occurs when starting or braking, but in this case It is a sudden vibration, and rather, it feels that the riding comfort is poor when the uneven surface described above is repeated. I often twist.

[0004]   Therefore, an object of the present invention is to solve the above-mentioned problems in the suspension for automobiles. , To obtain a suspension with a structure that can improve riding comfort It

[0005]

[Means for Solving the Problems]

  In order to achieve this purpose, the present invention provides a shock absorber that constitutes a suspension. A shovel and a control valve arranged in the hydraulic pressure supply line to the sover are used to In a suspension equipped with a structure that controls the spring constant of the shock absorber, The control valve is connected to the output side, and the input side has a vehicle speed sensor and steering angle sensor. The vehicle height sensor is composed of a stroke sensor for suspension on the front and rear wheels. Sensor and road surface detection means are respectively connected to the control unit, the control unit, When driving straight ahead, the signal from the road surface detection means and the signal from the vehicle height sensor are transmitted. Based on the number, the unevenness on the road surface is detected, and the difference in vehicle height between the front and rear wheels is set to a predetermined value. When the above is reached, the position of the control valve is adjusted according to the tendency of the difference in vehicle height. The feature is that it is set.

[0006]   Further, according to the present invention, the control unit controls whether the difference in vehicle height between the front wheel side and the rear wheel side is periodic or , If the time during which a difference of more than the specified value is generated continues for more than the specified time, It is characterized by setting the posture so that there is no difference between the two.

[0007]

[Action]

  According to the present invention, when the difference in vehicle height between the front and rear wheels reaches a predetermined value or more, Set the position of the control valve in the direction in which there is no difference, in other words, in the direction in which it is balanced. By continuously changing the spring constants of the shock absorbers on the front and rear wheels, The stroke change on the rear wheels is made constant.

[0008]

【Example】   Hereinafter, details of the embodiment of the present invention will be described with reference to FIGS.

[0009]   FIG. 1 is a block diagram showing an overall configuration of a suspension according to an embodiment of the present invention. It

[0010]   That is, the suspension 1 according to the present embodiment is the same on both the front wheel side and the rear wheel side. Of the same structure, the starting point is the constant displacement pump 2 driven by a motor. The hydraulic circuit is equipped with a hydraulic circuit that includes, for example, the check valve 3 and the accumulator. The oil of the constant displacement hydraulic pump 2 is supplied to the input side through the mullet 4 The control valve 5, the gas spring 6 connected to the output side of the control valve 5, and this gas A shock absorber 7 of a parallel construction connected to the spring 6 is arranged.   The control valve 5 described above is composed of a solenoid valve capable of switching between two positions and three positions. The normal position is set to a state in which the input-side oil passage and the output-side oil passage are shut off. A pressure signal to the oil return path and the gas spring 6 is generated by the drive signal from the control unit. You can set the additional route.   The gas spring 6 described above is provided between the control valve 5 and the shock absorber 7. They are arranged in a series relationship with these members in the oil passage, and the central part The gas chamber 6A and the pressure set by the control valve 5 at both ends. The oil chambers 6B and 6C are divided into three chambers.

[0011]   On the other hand, the shock absorber 7 is, for example, an automatic leveling machine controlled by hydraulic pressure. It is configured to have a function and is set by the pressure setting by the control valve 5. The position of the lower arm and the spring constant are changed.   In the figure, reference numeral 8 indicates a damping valve.

[0012]   The control unit 9 provided for driving the control valve 5 described above has a configuration shown in FIG. The configuration is shown in.   In other words, the control unit 9 does not show its details, but mainly uses the microcomputer. The vehicle speed sensor 10, the steering angle sensor 11, and the vehicle height sensor are provided on the input side. 12 and the road surface detection means 13 are connected to each other, and control is provided on the output side. The drive part of the valve 5 is connected.   Among these sensors, the vehicle height sensor 12 is the front and rear wheel suspension in the present embodiment. The stroke sensor installed in the shock absorber 7 Further, in the case of the present embodiment, the road surface detecting means 13 detects beforehand the unevenness of the road surface. It is composed of a sonar having a function as a preview sensor.

Then, in the above-described control unit 9, when the vehicle height is adjusted by changing the loaded weight, and information about the vehicle speed, the steering angle, the vehicle heights at the front and rear wheels, and the condition of the road surface is input, The spring constant of the gas spring 6 is set based on the map provided in the storage unit of the main body. That is, as the specific method of the spring constant setting described above, the front wheel side of the vehicle height (F _S) and the rear wheel side of the vehicle height absolute value a predetermined value of the difference between the (R _S), in this embodiment, for example, , Only when the difference between the strokes is 20mm or more, which is the driver's anxiety, when the difference is periodic, and in other words, when the difference is periodic, in other words, not at the time of starting or braking, but at the expressway. Only in the case where the seam is continuous, determine the direction in which the difference occurs, that is, the magnitude relationship of the vehicle height values of the front wheel side and the rear wheel side, and change the spring constant of the shock absorber according to this result. It has become. That is, in the present embodiment, when the difference between the vehicle heights of the front wheel side and the rear wheel side described above is obtained by subtracting the vehicle height of the rear wheel side from the front wheel side, and the absolute value of the above-mentioned difference is a predetermined value or more It is discriminated whether the tendency of the difference is in the positive direction or the negative direction.For example, when the tendency of the difference is positive, in other words, the stroke change on the front wheel side is larger than that on the rear wheel side. When the vehicle height is large or the vertical acceleration is large, the pressure is lower than the pressure at the vehicle height adjustment so that the spring constant of the gas spring 6 on the rear wheel side can be set to be small as shown in the map of FIG. As a value, the tendency for the stroke change on the rear wheel side to increase following the front wheel side is set so that the spring reaction force on the rear wheel side is reduced and the stroke change on the front and rear wheels is made constant. To do. When such a spring constant is reduced, the natural frequency on the vehicle body side can also be reduced, so that discomfort with respect to the riding comfort can be reduced.

[0014]   In addition, when the above-described tendency of the stroke difference is negative, in other words, the stroke on the front wheel side is When the change in the stroke is not large compared to the rear wheel side, contrary to the above case, the front wheel side In order that the spring constant of the gas spring 6 can be set to a large value, As the value is higher than the pressure during high adjustment, the amount of displacement on the rear wheel side is reduced and uncomfortable shaking Try to suppress. And, this adjustment of the spring constant continuously changes the vehicle height during running. To be run continuously by inputting into and continuously tracking the difference from that value Become.

[0015]   The setting of the spring constant on each wheel side was explained on the rear wheel side. Instead, as shown in the flow chart described later, the front wheel side is tilted in the opposite direction to the rear wheel side. The spring constant may be set in the opposite direction.   Therefore, by setting the spring constant of the gas spring 6 in the control unit 9 as described above, In the spring 6, the volume is changed by the supply pressure from the control valve 5, Change the spring constant at the change of the rope (P ・ V = K) to change the spring constant on the shock absorber 7 side. The net constant is set to a value different from that when adjusting the vehicle height, and the stroke changes at the front and rear wheels of the vehicle body are controlled. Standardized, for example, a bouncing that moves the pitching mode in parallel to the Z axis for both the front and rear wheels. It is possible to prevent the ride comfort from being deteriorated by changing the vibration mode to the ng mode. It will be.

[0016]   Further, when there is a difference in vehicle height between the front and rear wheels, it is necessary to adjust the spring constant. As described above, the determination of the occurrence time, which is the criterion for determining whether the And a method of determining by the number of times of the presence or absence of a difference equal to or more than a predetermined value of, for example, As shown in FIG. 5, the time exceeding the absolute value of the above-mentioned difference continues for a predetermined time or more. In some cases, it may be determined whether or not

[0017]   Since the present embodiment has the above-mentioned configuration, the operation of the control unit 9 will now be described. The operation will be described below with reference to the flowchart shown in FIG. It

[0018]   That is, for example, when pitching occurs in the road surface condition, Since the vehicle height on each rear wheel will be different, the difference in vehicle height will be determined and the difference will be eliminated. When it is determined that the occurrence of the difference is not sudden when the logarithmic value reaches a predetermined value or more. In this case, the posture of the control valve 5 can be set by determining the tendency of the difference. Specifically, when the tendency of the difference is positive as described above, the rear wheel side The position of the control valve 5 is set so as to reduce the spring constant, and the difference tends to occur. If is negative, set the control valve 5 in the direction of increasing the spring constant on the rear wheel side. Set.

[0019]   In this case, adjust the spring constant on the front wheel side instead of on the rear wheel side. Of course, it is possible, and in this case, the process of the step shown by the broken line in FIG. 6 is executed. It

[0020]   Therefore, the spring constants of the shock absorbers 7 at the front and rear wheels are continuously adjusted. Therefore, as shown in Fig. 7 (A), shocks from the road surface where continuous unevenness is repeated The spring constant of the shock absorber between the front and rear wheels against the vibration input to the absorber By correcting the variation of the elastic center position shown in FIG. 8, the pitch of FIG. 7 (B) can be corrected. As shown in the change in the Vibration of the car body in pitching mode due to continuous suspension, front and rear wheels are both parallel to the Z axis It can be changed to the bouncing mode, which is the mode in which it is operated.

[0021]

[Effect of device]

  As described above, according to the present invention, the stroke change of the shock absorber on the front and rear wheels is performed. Is continuously tracked, and the vehicle height obtained by changing the stroke is above a specified value. If there is a difference, the shock absorber using the control valve is oriented to balance this vehicle height. Changing the spring constant on the side of the driver makes the vibration mode on the vehicle side uncomfortable. It is possible to improve the riding comfort by setting it in a non-readable mode.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating an overall configuration of a suspension according to an embodiment of the present invention.

FIG. 2 is a block diagram for explaining a control unit of the control valve in the configuration shown in FIG.

FIG. 3 is a diagram for explaining characteristics of a control unit shown in FIG.

FIG. 4 is a diagram for explaining another characteristic of the control unit shown in FIG.

FIG. 5 is a diagram for explaining another characteristic of the control unit shown in FIG.

FIG. 6 is a flowchart for explaining the operation of the control unit shown in FIG.

FIG. 7 is a model diagram for explaining the action of the suspension shown in FIG.

FIG. 8 is a model diagram for explaining the relationship between the vibration mode of the vehicle body and the spring constant of the suspension.

[Explanation of symbols]

1 suspension 5 control valves 6 gas springs 6A gas chamber 6B, 6C Oil chambers located at both ends of the gas chamber 7 Shock absorber 9 control unit 10 vehicle speed sensor 11 Rudder angle sensor 12 Vehicle height sensor 13 Road surface detection means

Claims (2)

[Scope of utility model registration request] 1. A suspension having a structure for controlling a spring constant of a shock absorber by using a shock absorber which constitutes the suspension and a control valve arranged in a hydraulic pressure supply passage for the shock absorber. The control valve is connected to the output side, and the input side is connected to a vehicle speed sensor, a steering angle sensor, a vehicle height sensor composed of front and rear wheel side suspension stroke sensors, and a road surface detecting means, respectively. When the vehicle is traveling straight ahead, the control unit detects unevenness on the road surface based on the signal from the road surface detection means and the signal from the vehicle height sensor, and detects front and rear wheels. When the difference in vehicle height from the wheel side reaches a predetermined value or more, the position of the control valve is set according to the tendency of the difference in vehicle height. Tosu Suspension. 2. The suspension according to claim 1, wherein
The control unit controls the control valve when the vehicle height difference between the front wheel side and the rear wheel side is cyclic or the difference between the vehicle height and the rear wheel side continues for a predetermined time or more. A suspension that sets the posture so that there is no difference.