JPH04191113A - Damping force control device - Google Patents

Abstract

PURPOSE:To eliminate a detecting means at the side of rear wheels, and thereby reduce cost by controlling a front wheel side damping characteristics changing means with the vehicle behavior detected at the side of front wheels, computing the control time difference between each front and each rear wheel based on the detected vehicle speed, and thereby controlling a rear wheel side damping characteristics changing means so as to be delayed by the aforesaid time difference. CONSTITUTION:The output of the vehicle behavior detecting means (f) of front wheels composed of the vertical acceleration and load sensors of the front wheels is inputted into the front wheel control section 21 of a control means (g), and a control signal (k) is then outputted to the damping characteristics changing means (c) of a front wheel shock absorber (a), so that damping force characteristics are thereby changed. Meanwhile, the control time difference between each front and each rear wheel is operated by a time correcting section (h) based on the vehicle speed detected by a vehicle speed detecting means (e). And after the control signal (k) has been outputted from the front wheel control section (m), a control signal (n) is outputted to the damping characteristics changing means (d) of a rear wheel shock absorber (b) from a rear wheel control section (p) based on the control data of the front wheel control section (m), so that the damping characteristics of the rear wheels are thereby changed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a damping force control device for controlling the damping force characteristics of a shock absorber provided between sprung and unsprung parts of a vehicle.

(Prior Art) Conventionally, as a damping force control device, for example,
The one described in Japanese Patent No. 163011 is known.

This conventional damping force control device includes independent vehicle behavior detection means for each wheel, and independently performs damping force control for each wheel based on input signals from each vehicle behavior detection means. It was something.

(Problem to be Solved by the Invention) However, in the conventional damping force control device, it is necessary to provide a vehicle behavior detection means independently for each wheel, which increases the cost and requires installation. There was a problem in that it required more time and effort.

The present invention was made by focusing on such problems,
It is an object of the present invention to provide a damping force control device that can reduce costs and simplify manufacturing.

(Means for Solving the Problems) In the present invention, the control means includes a time correction unit that calculates the difference in passing time between the front wheels and the rear wheels based on the vehicle speed, and control data of the front wheel control unit that calculates the difference in time between the front wheels and the rear wheels. The above object is achieved by providing a rear wheel control section that outputs a control signal to the damping characteristic changing means on the rear wheel side based on the delayed signal.

That is, the damping force control device of the present invention independently controls the damping characteristics of the shock absorber A provided on the front wheel side and the shock absorber A provided on the rear wheel side, as shown in the diagram corresponding to the claims in FIG. Switchable damping characteristic changing means c, d, vehicle speed detecting means e for detecting vehicle speed, vehicle behavior detecting means f for detecting factors related to vehicle behavior on the front wheel side, and input signal 9 from the vehicle speed detecting means e. a time correction unit h that calculates a control time difference between the front wheels and the rear wheels based on the above, and a front wheel control unit that outputs a control signal k to the damping characteristic changing unit C on the front wheel side based on the input signal j from the vehicle behavior detection unit f. m, and a rear wheel control section p that outputs a control signal n to the damping characteristic changing means d on the rear wheel side based on the control data of the front wheel control section m delayed by the time difference obtained by the time correction section. A control means q was provided.

(Function) The function of the present invention will be explained. In addition, the symbols in the explanation are
This corresponds to Figure 1.

The vehicle behavior detection means f detects the state of factors related to vehicle behavior on the front wheel side, and the front wheel control section m outputs a control signal k based on the input signal j from the vehicle behavior detection means f. The damping characteristic changing means C of the buffer a is controlled to change to the optimum damping characteristic.

On the other hand, in the time correction section of the control means q, the vehicle speed detection means e
The control time difference between the front wheels and the rear wheels is determined based on the input signal 9 from the front wheel. In other words, since the rear wheels pass through almost the same location after the front wheels pass, the same control as that for the front wheels is applied.
This can be done for the rear wheels after a predetermined period of time, and this time difference is determined based on the vehicle speed. Furthermore, in the rear wheel control section p,
Based on the control data of the front wheel control section m delayed by the time difference obtained by the time correction section, a control signal n is output to the damping characteristic changing means d on the rear wheel side. Thereby, the damping characteristic changing means d on the rear wheel side is also controlled to the optimum damping characteristic.

In addition, in this case, the control time difference includes not only the passing time difference between the front wheels and the rear wheels, but also a response delay component from when the damping characteristic changing means d starts operating until the damping characteristic is actually changed. This can eliminate control delays.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the configuration of the embodiment will be explained.

FIG. 2 is an overall diagram showing a damping force control device according to an embodiment of the present invention. In the figure, 1 is a variable damping force type shock absorber, 2 is a pulse motor, and 3 is a vertical acceleration sensor (hereinafter referred to as a G sensor). ), 4 is a load sensor, 5 is a vehicle speed sensor, and 6 is a controller. Note that the shock absorber 1 and pulse motor 2 are provided for each wheel.

In the shock absorber 1, a damping characteristic changing means 7 such as an adjuster provided in the piston rod rotates to simultaneously switch the damping force ranges on the expansion side and the compression side into a low damping force range and a high damping force range. possible.

The pulse motor 2 has damping characteristic changing means 7 for the shock absorber 1.
The pulse motor 2 changes its position in multiple stages, thereby allowing the damping characteristic changing means 7 to change the damping force characteristic in multiple stages from a low damping force range to a high damping force range. It becomes.

The G sensor 3 is provided as a front wheel side vehicle behavior detection means, is installed on the vehicle body near the mounting position of the front wheel side shock absorber 1, and outputs an electric signal according to the vertical acceleration on the spring.

The load sensor 4 is also provided as a means for detecting vehicle behavior on the front wheel side, and is for measuring the unsprung and unsprung loads corresponding to the damping force of the shock absorber 1. The shock absorber 1 outputs an electric signal according to the input load from the shock absorber 1 to the vehicle body.

The vehicle speed sensor 5 is provided in the drive transmission system of the vehicle, detects the vehicle speed, and outputs an electrical signal corresponding to the vehicle speed.

The controller 6 constitutes a damping force control means, and the G sensor 3. Based on the input signals from the load sensor 4 and the vehicle speed sensor 5, a control signal is output to the pulse motor 2 in order to make the shock absorber 1 have optimal damping force characteristics.

That is, this controller 6 includes an interface circuit 61 that inputs signals from each sensor 3°4.5, and an A/D conversion circuit 6 that converts input analog signals into digital signals.
2. A CPU 64 that controls calculation 2 determination, etc., which will be described later, based on the numerical values stored in the memory circuit 63;
A drive circuit 65 is provided that outputs a control signal to the pulse motor 2 based on the control result of U64.

Next, the control contents of this controller 6 will be explained based on the flowchart shown in FIG.

In step 101, the front wheel side load value D (10 sign in the extension stroke, 1 sign in the compression stroke) input from the load sensor 4 and the sprung boat speed G of the front wheel are read, and the process proceeds to step 102.

In step 102, the spring progress level V is calculated from the sprung ship speed G.
An operation is performed to obtain O (10 sign for upward direction, 1 sign for downward direction), and the process proceeds to step 103.

In step 103, the vehicle speed ■ is read from the vehicle speed sensor 5, and in the subsequent step 104, the front wheels and the rear wheels are respectively passed based on this vehicle speed V and the distance between the front wheels and the rear wheels that is known in advance. The time difference Δd is calculated, and the process proceeds to step 105. In this case, the time required from when the controller 6 outputs the control signal to the pulse motor 2 until the necessary damping force is actually generated in the shock absorber 1 may be subtracted from the time difference T. .

In the following step 105, whether DXV,>O or not (
If a high damping force or a low damping force is required), the process proceeds to step 106, and if YES, the process proceeds to step 107.

In step 106, a control signal is output to set the damping characteristic changing means of the front wheel side shock absorber 1 to the low damping force range, and the process proceeds to step 108. On the other hand, in step 107, the damping characteristic changing means of the front wheel side shock absorber 1 is outputted. A control signal is output to set A to the high damping force range, and the process proceeds to step 108.

That is, in this embodiment, the sign of the front wheel side damping force value and the spring improvement degree V. The signs of match (DXv o > 0
) or not (oxvo <O), and - does not match (N
In case o), it is determined that the damping force generated by the shock absorber 1 is acting in the excitation direction against the vertical vibration of the vehicle body, and the damping force is controlled to the low damping force range, thereby improving the ride comfort of the vehicle. If both are secured and match (YES), it is determined that the damping force is acting in the damping direction against the vertical vibration of the vehicle body, and the damping force is controlled to the high damping force range, thereby reducing the fluctuation of the vehicle attitude. This is designed to ensure steering stability by suppressing the

In the subsequent step 108, the control signal data output to the damping characteristic changing means Y of the front wheel shock absorber 1 is stored in the memory circuit 63, and the process proceeds to step 109.

In step 109, the data of the control signal past by the time difference Δ is read from the memory circuit 63, and in the subsequent step 110, the control signal read from the memory circuit 63 is transferred to the damping characteristic changing means 7 of the rear wheel side shock absorber 1. Output to.

This completes one operation flow, and in the controller 6,
The above process is repeated.

Next, the operation of the embodiment will be explained.

(a) During front wheel side damping force control, the controller 6 determines the spring improvement level ■ obtained from the input signals from the G sensor 3 and load sensor 4 that detect vehicle behavior on the front wheel side. and the damping force value, and in order to form this damping characteristic, the drive circuit 65 outputs a control signal to each pulse motor 2, and the damping characteristic changing means A of the front wheel shock absorber 1 is activated. let

(b) During rear wheel side damping force control, the controller 6 uses past control signals of the control signals output to the front wheels, which are stored in the memory circuit 63, by the time difference Δd between the front wheels and the rear wheels, respectively. , this time, is output to the damping characteristic changing means 7 of the shock absorber 1 on the rear wheel side.

Therefore, when the rear wheels pass through the same place after the front wheels have passed, the shock absorber 1 on the rear wheel side is controlled to the optimum damping force range.

As explained above, in the damping force control device of this embodiment, in controlling the damping characteristics of the rear wheel side shock absorber 1, focusing on the fact that the rear wheels trace the same place that the front wheels passed, Since the same signal as the control signal output to the front wheel is output to the rear wheel side after being delayed by the passing time difference Δt between the front and rear wheels, the vehicle behavior of the rear wheel side, such as the G sensor 3 and load sensor 4, is It has the feature that the detection means can be omitted to reduce costs and the time and effort required to install these sensors, and it also requires calculations, judgments, etc. to find the optimal damping characteristics of the shock absorber 1 on the rear wheel side. The control system can be simplified by omitting the control circuit, which is also advantageous in that costs can be reduced.

Although the embodiment of the present invention has been described in detail with reference to the drawings above, the specific configuration is not limited to this embodiment. For example, in the embodiment, the control signal output to the rear wheels is simply output to the front wheels. I tried to delay it by T due to the difference in passing time with the rear wheel, but
As mentioned above, at this time, the time difference may be determined by taking into account the time from when the control signal is output to when the control characteristics are actually changed. The effect that the control response delay in 1 can be eliminated is obtained.

In addition, in the embodiment, the control signal output to the front wheel shock absorber 1 was used as the control data for the front wheel control unit that delayed by the time difference. A signal may also be used. In this case, the rear wheel control section calculates the optimum damping characteristic for the rear wheel based on the signals obtained with a time difference in this way, and outputs a control signal based on the result. Such control is effective, for example, when the control contents are different between the front wheels and the rear wheels.
In this case as well, an effect can be obtained in that the sensor on the rear wheel side can be omitted.

In addition, in the embodiment, as a vehicle behavior detection means for detecting factors related to vehicle behavior, a vehicle behavior detection means that detects the input load to the vehicle body and the speed of the ship on a spring has been shown, but for example, it is possible to detect the condition of the road surface using sound waves, light, etc. It also includes means for detecting things related to vehicle behavior that are not the actual behavior of the vehicle, such as sensors that detect the behavior of the vehicle.

Furthermore, in the embodiment, an example was shown in which the optimal damping characteristic is determined by calculation, but a data map may also be indexed.

Further, in the embodiment, a vehicle speed sensor provided in the drive system is shown as the vehicle speed detecting means, but the vehicle speed detecting means may be constituted by an acceleration detecting means for detecting the acceleration of the vehicle and a calculation means for calculating the speed from the acceleration. Good too.

(Effects of the Invention) As described above, in the damping force control device of the present invention, the control means includes a time correction section that calculates a passing time difference between the front wheels and the rear wheels based on the vehicle speed, and control data for the front wheel control section. The means includes a rear wheel control section that outputs a control signal to the damping characteristic changing means on the rear wheel side based on a signal delayed by the time difference between the front wheels and the rear wheels, so that factors related to vehicle behavior on the rear wheel side can be considered. This eliminates the need for a means of detection, which has the effect of reducing costs and installation effort.In addition, since control is based on the vehicle behavior of the front wheels, the rear wheels It is possible to eliminate the control delay that occurs when control is performed after detecting vehicle behavior.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is an overall view showing an embodiment of the damping force control device of the present invention, and FIG. 3 is a flowchart showing the operation flow of the controller. a... (front wheel side) shock absorber b... (rear wheel side) shock absorber C... (front wheel side) damping characteristic changing means d... (rear wheel side) damping characteristic changing means e...Vehicle speed detection means f...Vehicle behavior detection means 9...Input signal h...Time correction section j...Input signal k...Control signal m...Front wheel control section n...・Control signal p...Rear wheel control section q...Control means

Claims (1)

[Scope of Claims] 1) damping characteristic changing means capable of independently switching the damping characteristics of shock absorbers provided on each front wheel side and rear wheel side, vehicle speed detecting means for detecting vehicle speed, and front wheel side a time correction section that calculates a control time difference between the front wheels and the rear wheels based on the input signal from the vehicle speed detection means, based on the input signal from the vehicle behavior detection means; a front wheel control section that outputs a control signal to the front wheel side damping characteristic changing means based on the control data of the front wheel control section delayed by the time difference obtained by the time correction section, and a front wheel side damping characteristic changing means that outputs a control signal to the front wheel side damping characteristic changing means A damping force control device comprising: a control means having a rear wheel control section that outputs a control signal.