JPS59186710A - Suspension for automobile - Google Patents

Abstract

PURPOSE:To reduce the rolling of a car body in time of turning a car around as well as to make improvements in steerage, by adjusting a suspension device so as to cause both suspension characteristics of a front wheel at the same side as the turning direction of the car and a rear wheel situated at least on a diagonal line to this front wheel to be made harder than others. CONSTITUTION:When an automobile is steered so as to turn it around to the right, for example, at more than a fixed speed, a roll signal E being more than a fixed level and a right steering signal F are inputted into a controller 16 from a roll sensor 17 and a steering direction sensor 18. On the other hand, step motors 122-124 of suspension systems 6-8 for a right front wheel 2 and both rear wheels 3 and 4 are all driven by the controller 16. With this constitution, interconnection between top and bottom oil chambers of each damper 10 in these suspension systems 6-8 is cut off, while space between an air chamber 1 and an accumulator 14 is as well cut off, thus suspension characteristics in these suspension systems 6-8 are relatively hardened and the occurrence of rolling in a car body is checked.

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 spring constant of a spring and the damping rate of a damper, that is, the suspension characteristics of a suspension that constitute an automobile suspension, can be changed in accordance with driving conditions. 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 shock absorber on the rear wheel side is lowered relative to the front wheel side. Relating to a "vehicle suspension" characterized in that the steering characteristic is an understeer characteristic at low speeds, and the damping force relationship at low speeds is opposite to that at high speeds, so that the steering characteristics are neutral steering characteristics or oversteer characteristics.
A new idea has been disclosed. This is intended to simultaneously provide straight-line stability at high speeds and turning maneuverability at low speeds. However, in order to improve the overall maneuverability and riding comfort of an automobile, it is insufficient to simply change the suspension characteristics depending on the vehicle speed as in the above-mentioned invention. Particularly at the same time, when cornering maneuverability is improved by making the suspension characteristics of the front wheels relatively soft and making the steering characteristics tend to oversteer or weakly understeer, the car body turns to the opposite side of the turning direction. There is a problem in that the rolling of the vehicle increases, causing discomfort to the staff members, and if the suspension characteristics of both the front and rear wheels are made stiffer to prevent this, there is also the problem that turning maneuverability worsens. It is important to solve these problems by appropriately controlling the suspension characteristics in order to improve the maneuverability and ride comfort of automobiles. The present invention has focused on the above points, and aims to simultaneously improve maneuverability and ride comfort during turns in a suspension whose suspension characteristics are variably controlled according to driving conditions. The present invention provides suspension means for suspending a vehicle body on front wheels and rear wheels, adjustment means for changing the suspension characteristics of the suspension means, a turning sensor for detecting the turning direction of the vehicle, and a controller for operating the adjustment means. The controller receives the output signal from the turning sensor and suspends the front wheel on the same side as the turning direction and at least the rear wheel on the diagonal line of the front wheel of the two rear wheels. It is characterized in that it is configured to output a drive signal to the adjustment means so as to make the characteristics relatively hard compared to others. According to such a configuration, when turning, J'3 The rolling of the vehicle body is reduced, and the angesteering tendency of the steering characteristics is weakened, and good turning maneuverability is obtained, thereby achieving the above objects.The present invention will be described below based on embodiments shown in the drawings. As shown in Fig. 1, suspension devices 5' and 6 for suspending the vehicle body are mounted on the left and right front wheels 1.2 and the left and right rear wheels 3.4.
, 7.8, respectively. Each of these suspension devices 5 to 8 includes a coil spring 9, a damper 10,
It consists of an air chamber 11, a damper 10 (as described later, the damping rate can be switched in two stages, and a step motor 12 is provided as an actuator for the switching. Chamber 11 is pipe 13
An electromagnetic valve 15 is installed between the air chamber 11 and the accumulator 14 to disconnect the two from each other. A controller 16 is provided that outputs drive signals A, B, C, and D to the step motor 12 and electromagnetic valve 15 in each suspension device 5 to 8, respectively. For example, an acceleration detection type roll sensor 17 that detects lateral G and a steering direction sensor 18 that detects, for example, the rotation direction of a steering wheel are configured to receive a roll signal E and a steering direction signal @F, respectively. . Here, the specific structure of the suspension device will be explained. As shown in FIG.
2, the suspension device 5 (6, 7, 8) is movable up and down relative to the upper case 23 that forms the air chamber 11. The lower end of the upper case 23 and the upper end of the lower case 24 are connected to a rolling tie A7.
Both cases 2 are connected by a flamm 25.
3.24 is partitioned off by a seal member 26. The lower case 24 further includes an outer cylinder 27 and an inner cylinder 28, and a piston loft 29 inside the inner cylinder 28.
is inserted therethrough so as to be relatively vertically slidable, and the interior of the inner cylinder 28 is partitioned into an upper oil chamber 31 and a lower oil chamber 32 by a main rev 30 provided at the lower end of the piston rod 29. In addition, a bottom valve 3 is provided at the lower end of the inner cylinder 28.
3, and the space between the inner cylinder 28 and the outer cylinder 27 is a reservoir chamber 34. Here, the outer cylinder 27 is equipped with several supports (brackets 27 a h<

[I'm being pulled. The main valve 30 also has a check valve 30a that connects an upper oil chamber 31 to a lower oil chamber 3, as shown in an enlarged view in FIG.
The extension side orifice 30b is configured to allow hydraulic oil to pass only to the 2 side, and the contraction side orifice 3Qd is configured to allow hydraulic oil to pass only from the lower oil chamber 32 to the upper oil chamber 31 side by the check valve 30G. is provided. These constitute a damper 10 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 screws 1 to 2 in the damper 10
9 is hollow, and a control rod 35 is rotatably inserted into the hollow portion. This rod 35 is rotated by the step motor 12 via a rotation key 36 engaged at its upper end, and is connected to a valve body 37 provided at the lower end of the control rod 35 and screws 1 to 29. A by the valve case 38 provided at the lower end.
A refit valve 39 is configured. That is, as shown in FIG. 4, a passage 38a that communicates the lower oil chamber 31 and the lower oil chamber 32 formed in the cylindrical valve case 38 is connected to the case 3.
The communication is interrupted by the rotation of the valve body 37 fitted in the valve body 8, or communicated with the audience chair 37a provided on the valve body 37. As a result, the lower oil chamber 31 and the lower oil chamber 32 are in communication only through the extension side orifice 301 leading to the main valve 30 or the contraction side orifice 30'd, and in addition to this, the orifice valve 39
The attenuation rate of the tamper 10 is also switched to a state in which it is communicated through the orifice 37a, and the damping rate of the tamper 10 is switched to two levels, ie, a hard state (hard suspension characteristics) and a soft state (soft suspension characteristics). Further, as shown in FIG. 2, the upper case 23 and the lower case 24 are each provided with a spring holder (4.0.41), and the coil spring 9 is mounted between these, so that the coil spring 9 and the air in the air chamber 11 constitute the springs of the suspension device 5 (6, 7, 8). Since j& is supplied to the A=V combulator 14 through the solenoid valve 15, the amount of air acting as a spring is increased or decreased between the closed state and the heard state of the solenoid valve 15, and this causes the spring constant of the spring to vary in size. In other words, the controller 16 is configured as shown in FIG. The devices include a comparator 51 to which the roll signal E from the roll sensor 17 is input, and a signal Q from the steering direction sensor 18.
A comparator 52 receives a right steering signal F(R) indicating rightward steering of F, and a comparator 53 receives a left steering signal F(L) indicating leftward steering. has. A signal E' is output from the comparator 51 when the magnitude of rolling of the vehicle body indicated by the roll signal E is above a certain level, and a signal E' is output from the comparator 51 when the amount of rightward steering indicated by the right steering signal F(R) is above a certain level. The signal F(
R)' is input to the AND circuit 5/I for right turn,
Furthermore, the signal E' outputted from the comparator 51 and the signal @F<L)' outputted from the comparator 53 when the leftward steering amount indicated by the left steering signal F (L) is above a certain level. is input to the AND circuit 55 for left turn. The output signal G of the AND circuit 54 for turning to the right turns on the transistor 56, and as a result, the circuits B', C', and D' become conductive except for the circuit A' which is prevented from being conductive by the tie auto 57. (That is, the drive signals B, C, and D shown in FIG. valves 152, 15
3, avoid operating 154. Similarly, AND for left turn
The output signal 1 of the circuit 55 turns on the transistor 58, so that the circuits ', C', and D' conduct, except for the circuit B', which is prevented from conducting by the diode 59 (as shown in FIG. (driving words A, C, D are output),
Suspension device 5 for left front wheel 1 and left and right rear wheels 3.4
, 7, 84 step motors 12+, 123, 1
2a and solenoid valves 15+, 153, and 154. Next, the operation of the above embodiment will be explained. First, when the vehicle is traveling straight or making a very gentle turn, the signals E and F from the roll sensor 17 and the steering direction sensor 18 are constant and below Hertz, so the controller 1
6 does not output the drive signal ~D. 3. That is, the circuits A' to D' shown in FIG. There is no C. Therefore, in each of the suspension devices 5 to 8, the valve body 37 of the orifice valve 39 constituting the tamper 10 is in the state shown in FIG. are communicated by the passage 38a and the orifice 37a, and when the electromagnetic valve 15 is opened, the air chamber 11 constituting the spring is communicated with the accumulator 14.In other words, each of the lease pension devices 5 to 8 is free from tampering. Therefore, the vehicle is in a comfortable riding state.Now suppose that the driver steers the vehicle to turn to the right with more than a certain level of sharpness. At this time, the roll sensor 17 and the steering direction sensor υ18 are constant, and the roll signal E and the right steering signal F(R) which are equal to or higher than PEL are detected by the controller 16.
As a result, signals E' and F(R)' are outputted from the comparators 51 and 52 in the controller 16, and accordingly, the right turn AND circuit 54 ignites the transistors 1 to 56. The message @G is output. Therefore,
From the controller 16 to the right front wheel 2 and the left and right rear wheels 3.4
The step motors 122, 123, 124 and the solenoid valves 152°, 1 in the suspension devices 6, 7.8
Drive signal @B for 53,154. C and D are output. Accordingly, in the suspension system fif6, 7.8, the valve body 37 of the orifice valve 39 constituting the damper 1o rotates by a certain angle from the state shown in FIG. The passage 38a communicating with the oil chamber 32 is cut off, and the air chamber 11 and the accumulator 14 are cut off, so that the suspension devices 6, 7 of the right front wheel 2 and the left and right rear wheels 3.4 are cut off.
．． At 8, the aH tamper and spring are switched to the hard state. In addition, when steering to the left, signals E' and F (L)' are output from the comparator 51.53 of the controller 16, and the signals E' and F (L)' are outputted from the transistor 58 through the AND circuit 55 for left turning.
is ignited, the left front wheel 1 and the left and right rear wheels 3.
Step motors 12+, 123, 124 and solenoid valves 15+, 153 in suspension device 5.7.8 of 4
, 154, drive signals A, C, and D are output. In this way, when turning, the suspension devices of the front wheels on the same side as the turning direction and the left and right rear wheels are stiffened, and as a result, rolling characteristics and steering characteristics as shown in FIGS. 6 and 7 are obtained. In other words, as shown in Figure 6, the roll angle of the vehicle body relative to lateral G during turning becomes smaller as the suspension characteristics change from soft across the entire width to hard across the entire width, and as the number of hard wheels increases. In this example, the roll angle is smaller than when only the left and right rear wheels are made hard, and rolling characteristics similar to those obtained when all wheels are made hard are obtained. In addition, the steering characteristics (the ratio of the steering wheel angle θ to the steering wheel angle θ0 during extremely low-speed turning when the lateral G is increased under Affi turning radius and constant diameter conditions) are determined only for the left and right rear wheels, as shown in Figure 7. When is set to hard, the antasteer tendency is weakened the most and turning maneuverability is improved, but in the case of the above embodiment, turning maneuverability close to this can be obtained. In the above embodiment, when turning, the suspension characteristics of the front wheel on the same side as the turning direction and the left and right rear wheels are stiffened, but only the front wheel on the same side as the turning direction and the rear wheels on the diagonal line of this front wheel are A similar effect can be obtained if the material is hardened. Further, in the above embodiment, the suspension characteristics are controlled for both the damper and the spring, but it is also possible to control the suspension characteristics of only one of them (and furthermore, the suspension characteristics of only one of the dampers and the springs are controlled). For example, the controller 16 may be equipped with a vehicle speed sensor, etc., and other components may be added to the controller 16, so that in addition to the control during turning as described above, the suspension characteristics may be controlled in accordance with the vehicle speed, etc. when traveling straight. According to the present invention, it is possible to reduce the rolling of the vehicle body when turning a car, weaken the unsteer tendency, and improve turning maneuverability.Thereby, when turning J' This means that you can get excellent ride comfort and maneuverability at the same time.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a control system diagram, FIG. 2 is a vertical cross-sectional view showing the specific configuration of the suspension device, FIG. 3 is an enlarged vertical cross-sectional view of the main part, and FIG. 5 is a circuit diagram showing the configuration of the controller, FIG. 6 is a graph showing rolling characteristics according to the embodiment, and FIG. 7 is a graph showing steering characteristics. 1.2... Front wheel, 3.4... Rear wheel, 5-8... Suspension means (suspension device), 12.15... Adjustment means (12... Step motor, 15... solenoid valve)
, 16...Controller, 17.18...Turning sensor (17...Roll sensor, 18...Steering direction sensor) Applicant Toyo Kogyo Co., Ltd. Figure 3 Figure 4

Claims (1)

[Claims] (1) Suspension means for suspending the vehicle body on the front wheels and the rear wheels, respectively;
An adjusting means for changing the suspension characteristics of the suspension means, a turning sensor for detecting the turning direction of the vehicle, and a controller 1-0- for operating the adjusting means, and the controller 1-0-
receives the output signal from the turning sensor, and makes the suspension characteristics of the front wheel on the same side as the turning direction and at least the rear wheel on the diagonal line of the front wheel of the two rear wheels relatively stiffer than the others. A suspension for an automobile, characterized in that the suspension is configured to output a drive signal to the adjustment means.