JPS59186711A - Suspension for automobile - Google Patents

Abstract

PURPOSE:To relieve the degree of pitching motion in times of starting and/or quick acceleration, by adjusting a suspension characteristic to come into being hard when accelerator opening goes beyond the specified one, while controlling it so as to stop the said adjustment when the acceleration goes down to below the specified value. CONSTITUTION:When an accelerator pedal is stepped on for more than the specified opening in time of car starting or the like, step motors 8 and solenoid valves 11 of each of suspension systems 3 and 4 for both front and rear wheels are driven by a controller 12 on the basis of the output of an accelerator opening sensor 13. With this constitution, interconnection between top and bottom oil chambers of each damper 10 of these suspension systems 3 and 4 is cut off, while space between an air chamber 7 and an accumulator 10 is also cut off whereby a suspension characteristic of these suspension systems 3 and 4 is made to come into a state of being hard. On the other hand, after completion of the starting or the like, when the opening of an accelerator goes down to below the specified value, the driving of each of step motors 8 and solenoid valves 11 is stopped at a specified time lag, thus the said suspension characteristic is brought back to a state of softness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automobile suspension, and more particularly to a suspension whose suspension characteristics are variably controlled according to driving conditions.

It is already known that the damping rate of the spring constant of the spring that makes up the suspension of an automobile, that is, the suspension characteristics of the suspension, changes depending on the driving condition. For example, according to Japanese Utility Model Application Publication No. 55-109008, in a car equipped with shock absorbers on the front and rear wheels, at high speeds the damping force of the rear shock absorber is lowered relative to the front wheel. An idea has been disclosed regarding a [vehicle suspension] characterized in that the steering characteristic is an understeer characteristic, and the damping force relationship at low speeds is reversed from that at high speeds, and is characterized by neutral steering characteristics or oversteer characteristics. This is intended to simultaneously provide straight-line stability at high speeds and turning maneuverability at low speeds.

However, in order to generally improve the drivability and ride comfort of a vehicle, it is not sufficient to simply change the suspension characteristics depending on the vehicle speed as in the above-mentioned idea.

For example, when starting or accelerating suddenly, the vehicle body pitches backwards and downwards due to the shift of the load acting on the front and rear wheels, but such body pitching causes discomfort to the occupants. It is important to prevent or reduce this effect by appropriately controlling the suspension characteristics in order to improve ride comfort when starting the vehicle.

A possible solution to this problem is to detect the acceleration of the vehicle and make the suspension characteristics harder when the acceleration exceeds a certain level, such as when starting or suddenly accelerating, to reduce pitching of the vehicle body. However, pitching of the vehicle body occurs in response to acceleration, so if the suspension characteristics are made harder while acceleration increases above a certain level, there will be a delay in control response, which will cause the most discomfort. When the vehicle body pitches from the normal posture to the backward tilted posture, the suspension characteristics have not yet been switched to bar 1-.

To deal with this, it is conceivable to detect the accelerator opening and, when the opening reaches a certain level, to control the frame characteristics so as to follow the heart. In other words, pitching when starting or sudden acceleration occurs after the accelerator pedal is depressed.
This occurs when acceleration increases with an increase in engine output, so if you control the accelerator opening accordingly, you can adjust the suspension characteristics in advance when acceleration increases, that is, when the vehicle pitches most violently. It is possible to leave it. However, in this case, when starting or accelerating is completed and the accelerator pedal is released, the suspension characteristics are first returned to the soft state, and then the vehicle body pitches from the backward leaning position to the normal position. It is only possible to cope with the pitching motion at the time of starting or completing acceleration.

The present invention addresses the above-mentioned problems, and provides a suspension that variably controls the suspension characteristics according to driving conditions. The purpose is to simultaneously alleviate both pitching movements in the opposite direction, thereby improving the ride comfort of the automobile in these cases.

That is, the present invention provides a single suspension device with variable suspension characteristics, an adjusting means for changing the suspension characteristics of the suspension device, a controller for operating the adjusting means, and an accelerator distance sensor for detecting the accelerator opening degree. and an acceleration sensor for detecting acceleration and mountain deflection of the automobile, and the controller receives output signals from the accelerator opening sensor and the acceleration sensor, detects that the accelerator opening has increased above a certain level, and detects the increase in the accelerator opening above a certain level. The adjustment means is configured to output a drive signal for hardening the suspension characteristics] and to stop outputting the drive signal when it detects that the acceleration has decreased below a certain level. do. According to such a configuration, the suspension characteristics of the suspension device are adjusted to the heart state before the vehicle body starts pitching motion when starting or suddenly accelerating, and the vehicle body returns to a substantially normal posture when starting or suddenly accelerating. This means that the suspension characteristics are maintained in a hard state until the end of the vehicle, and sudden pitching motion of the vehicle body in these cases is prevented.

Hereinafter, the present invention will be explained based on embodiments shown in the drawings.

As shown in FIG. 1, front wheels 1, 1 and rear wheels 2, 2 are provided with suspension devices 3, 3, 4.4, respectively, for suspending the vehicle body. These suspension devices 3, 3,
4.4 are all composed of a coil spring 5, a damper 6, and an air chamber 7, but the damper 6 has a J: shape structure described later, and the damping rate can be switched between two stages. A step motor 8 is provided as an actuator. Further, the air chamber 7 is connected to the accumulator 10 via a pipe 9, and a solenoid valve 1 is provided between the air chamber 7 and the accumulator 10 to disconnect communication between the two.
1 is installed. And each suspension device 3
, 3, 4.4 drive signal A for the step motor 8 and the solenoid valve 11.

The controllers 1 to 12 are provided with a controller 1 and a roller 12 that output signals B respectively, and the controllers 1 to 12 receive a signal 7 from an accelerator distance sensor 13 that detects the opening degree (depression level) of the accelerator pedal.
It is configured so that the acceleration signal from the acceleration sensor 14 that detects the acceleration of the automobile is inputted.

Here, the specific structure of the suspension device will be explained.

As shown in FIG. 2, a suspension device 3 whose upper end is fixed to the vehicle body via a claw side member 21 and an elastic body 22.
(/1.) indicates the upper case 23 forming the air chamber 7.
and a lower case 24 that can move up and down relative to the case 23. The lower end of the upper case 23 and the upper end of the lower case 24 are connected by a rolling diaphragm 25, and The interior of the cases 23 and 24 is partitioned by a seal member 26. Lower case 24
The piston rod 29 is further composed of an outer cylinder 27 and an inner cylinder 28, and a piston rod 29 is inserted into the inner cylinder 28 so as to be relatively slidable up and down, and is provided at the lower end of the screw rod 29. The interior of the inner cylinder 28 is partitioned into an upper oil chamber 31 and a lower oil chamber 32 by a main valve 30. Also,
The lower end of the inner cylinder 28 is provided with a cylinder 1 to a valve 33, and the space between the inner cylinder 28 and the outer cylinder 27 is a reservoir chamber 3/1. Here, the support mechanism that rotatably supports the wheel is attached to the outer cylinder 27 using the brackets 1 to 1.
27a is stepped. Also, the main valve 3
As shown in an enlarged view in FIG. 3, the extension side orifice 30b is configured to allow hydraulic oil to pass only from the upper oil chamber 31 to the lower oil chamber 32 side by the check valve 30a, and the check valve 30c. The contraction side orifice 3 allows hydraulic oil to pass only from the lower oil chamber 32 to the upper oil chamber 31 side.
These components constitute a damper 6 that quickly damps vibrations between the upper case 23 and the lower case 24, that is, the vehicle body side and the wheel side.

However, the tamper 6 (the above-mentioned piston rod 1'
29 is hollow, and the controller 1 to the roll rod 35 are rotatably inserted thereinto. This rod 35 is
It is rotated by the step motor 8 through a rotary key 36 engaged at the upper end, and a valve body 37 provided at the lower end of the control rod 35 and a valve body 37 provided at the lower end of the piston rods 1 and 2. An orifice valve 39 is constituted by the valve case 38 and the valve case 38 . That is, an upper oil chamber 31 formed in a cylindrical valve case 38 (not shown in FIG. 4)
A passage 38a that communicates between the lower oil chamber 32 and the lower oil chamber 32 is blocked by rotation of the valve body 37 fitted in the case 38, or communicated by an orifice 37a provided in the valve body 37. In addition to this, the upper oil chamber 31 and the lower oil chamber 32 are in communication only through the extension orifice 3Qb or the contraction orifice 30d connected to the main valve 30, and in addition to this, the orifice valve 39
The attenuation rate of the tamper 6 is switched to a state in which it is in communication with the orifice 37a, and the attenuation rate of the tamper 6 is switched to two levels, ie, a hard state and a soft state.

Further, as shown in FIG. 2, the upper case 23 and the lower case 24 are each provided with a spring receiver iJ4.0.41, and the coil spring 5 is mounted between them. , the air in the air chamber 7 constitutes the spring of the suspension device 3 (4).In that case, the air chamber 7 is connected to the accumulator 10 via the pipe 9 and the solenoid valve 11 as described above. Therefore, the solenoid valve 11
The amount of air acting as a spring is increased by 6J between the closed state and the closed state, thereby switching the spring constant of the spring into two stages, large and small, that is, a bar state and a soft state. It will be done.

On the other hand, the controller 12 has a comparator 40. to which the accelerator distance @C and acceleration signal 8D from the accelerator opening sensor 13 and the acceleration sensor 14 are inputted, respectively, as shown in FIG. ．． 41, an OR circuit 42 to which the outputs No. 3 E and F from these comparators 40 and 41 are input;
a transistor 43 which is fired by the output signal G of the circuit 42, and when the transistor 43 is fired the circuit Δ'.

B' is applied with force (the drive signals A and B shown in FIG. 1 are output), and the step motor 8 and electromagnetic suspension l'11 in J3 of the suspension devices 3 and 4 harden the damper and spring, respectively. It is configured to operate as follows.

Next, the operation of the above embodiment will be explained.

First, when the car starts or suddenly accelerates, if the accelerator pedal is depressed beyond a certain degree, the accelerator position sensor 1
3 to the comparator 40 of the controller 1 to the roller 12, the accelerator opening signal C of a certain level or higher is input to the comparator 40 and the OR circuit 42 in the controller 12.
The transistor 43 is turned on via the controller 1 to the roller 12, thereby outputting drive signals Δ and B to the step motor 8 and the electromagnetic valve 11 of the suspension devices 3 and 4. Therefore, in the suspension devices 3 and 4 for the front and rear wheels, the valve body 37 of the orifice valve 39 constituting the damper 6 is rotated by a certain angle from the state shown in FIG. The passage 38a that communicates the upper oil chamber 31 and the lower oil chamber 32 of 6 is shut off, and the electromagnetic valve 11 is closed, so that the air chamber 7 and the accumulator 10 forming the spring are shut off. As a result, the dampers and springs of the suspension devices 3 and 4 are both in a hard state.

However, this control is performed by a certain delay time t (usually 0.
This is done after a period of 1 to 0.5 seconds has elapsed, but at that point the engine output or acceleration has not increased sufficiently and the pitching of the vehicle body is still small. Then, when the engine output is TR and the acceleration suddenly rises, the vehicle body pitches from the normal position to the backward leaning position (section a in Figure 6), but at this point, the lease pension device 3.4 Since the suspension characteristics are already hard, this pitching motion is reliably alleviated. In this case, the comparator 41 to which the acceleration signal is input is inputted after the signal E from the comparator 40 is output.
F is output.

On the other hand, when the accelerator opening degree is released after the start or acceleration is completed, the output of the signal E from the comparator 40 is stopped when the accelerator opening degree falls below the constant value XO. At this time, the acceleration is still in a large state, and then as the acceleration decreases, the vehicle body pitches from the backward leaning position to the normal position (section (b)). Therefore, if the suspension characteristics of the suspension device 3.4 are returned to soft by stopping the output of the signal E depending on the accelerator opening, it is impossible to cope with the pitching motion in this case. However, in this case, even after the accelerator opening decreases below the constant value xO, until the acceleration decreases below the constant value YO, the comparator 41 inputting the acceleration signal
continues to be output, and the signal @F causes the drive signals △ and B to be output via the OR circuit /12 and transistors 1 to 43, and the suspension system maintains the suspension characteristics of 3 and 4 in the hard state. It is. As a result, the pitching movement of the vehicle body from a backward tilted position to a normal position when starting or completing acceleration is also alleviated.

As a result, the acceleration decreases below the above-mentioned constant value YO, the output of the signal @F from the comparator 41 is stopped, and the delay time Δt
After , the output of the drive signals A and B is stopped,
As a result, the suspension characteristics of the suspension devices 3 and 4 are returned to the state of soft 1~, but at this point, the vehicle body has already returned to its substantially normal posture.

In the above embodiments, the suspension characteristics are controlled for both the tamper and the spring, but the suspension characteristics of only one of them may be variably controlled. In addition, it is equipped with a sensor that detects other driving conditions such as a vehicle speed sensor, and also changes the configuration of controller 1 to roller (J) to adjust the suspension characteristics to driving conditions other than when starting or sudden acceleration. Corresponding variable control may be performed.

As described above, according to the present invention, the pitching motion of the vehicle body is alleviated when the vehicle starts or suddenly accelerates, and when the vehicle starts or suddenly accelerates.

This eliminates the discomfort caused by the pitching motion in these cases and improves the ride comfort of the vehicle.

[Brief explanation of the drawing]

Figures 1 to 6 show embodiments of the present invention. Figure 1 is a control system diagram, Figure 2 is a vertical cross-sectional view showing the specific configuration of the 4)-suspension device, and Figure 3 is its main components. FIG. 14 is an enlarged cross-sectional view, FIG. 5 is a circuit diagram showing the configuration of the controller, and FIG. 5 is a time chart showing the operation. 3.4... Suspension device, 8.11... Adjustment means (8... Step motor, 11... Solenoid valve),
12... Control roller, 13... Accelerator opening sensor, 14... Acceleration sensor Applicant Toyo Kogyo Co., Ltd. Figure 3 35 Figure 4

Claims (1)

[Claims] (1) A suspension device with variable suspension characteristics, an adjusting means for changing the suspension characteristics of the suspension device, an accelerator opening sensor for detecting the accelerator opening, an acceleration sensor for detecting the acceleration of the automobile, and the adjusting means. a controller for operating the suspension device, and the controller receives output signals from the accelerator opening sensor and the acceleration sensor, detects that the accelerator opening has increased beyond a certain level, and causes the adjustment means to adjust the suspension device. A suspension for an automobile, characterized in that the suspension is configured to output a drive signal for hardening suspension characteristics, and to stop outputting the drive signal upon detecting that acceleration has decreased below a certain level. .