JPH04146808A - Suspension alignment controller - Google Patents

Abstract

PURPOSE:To secure excellent riding quality covering broad running speed range of from low speed to high speed by providing the control section for coping with car speed to output operation control signals to a suspension rigidity controlling means so as to reduce the longitudinal direction rigidity of a suspension with the increase in car speed. CONSTITUTION:A suspension bushing 1 with rigidity control mechanism controls control valves 10a and 10b based on the information from the sensor 12 such as a brake sensor 12a and steering angle sensor 12b by means of a controller 11. The control valve 10a controls longitudinal direction rigidity, and the control valve 10b controls cross direction rigidity. The control section 11b of a controller 11 for coping with car speed performs controlling based on the information from a car speed sensor 12c so as to reduce the longitudinal direction rigidity of a suspension as the vehicle runs faster in a given high sped range and keep a small value of rigidity constant when the speed of vehicle reaches a given value of high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a suspension alignment control device suitable for use in an automobile suspension.

[Prior Art] Vehicles such as automobiles have been developed in which the rigidity of the suspension can be adjusted according to the driver's preference, for example.

Mechanisms for adjusting the rigidity of such suspensions include those that adjust the roll rigidity by changing the mounting points of the stabilizer, and those that adjust the rigidity of the suspension bushings that elastically attach the suspension to the vehicle body. There are some types that do.

[Problems to be Solved by the Invention] By the way, when adjusting the stiffness of a suspension, the problem is in which direction the stiffness should be adjusted.

The stiffness of the suspension includes, for example, the stiffness in the vertical direction with respect to the vehicle body (vertical stiffness), the stiffness in the longitudinal direction (front-rear stiffness), and the stiffness in the lateral direction (lateral stiffness).

In particular, the longitudinal stiffness affects the ride comfort, but the degree of this influence changes depending on the vehicle speed.For example, the greater the vehicle speed, the more likely the strength of the longitudinal stiffness to adversely affect the ride comfort.

However, at present, control corresponding to vehicle speed is not performed, and it is not possible to always ensure good ride comfort over a wide range of running speeds.

The present invention was devised in view of such problems, and
By adjusting the front and rear stiffness according to the vehicle speed, it can be used in a wide range of driving speeds from low to high speeds.

This ensures good ride comfort at all times. An object of the present invention is to provide a suspension alignment control device.

[Means for Solving the Problem] Therefore, the suspension alignment control device of the present invention includes a suspension stiffness adjustment means that can adjust the longitudinal stiffness of a suspension provided in a vehicle, and a control means that controls the suspension stiffness adjustment means. and a vehicle speed sensor for detecting the traveling speed of the vehicle, and the control means controls the suspension stiffness adjustment means to weaken the longitudinal stiffness of the suspension as the vehicle speed increases, based on information from the vehicle speed sensor. It is characterized by having a vehicle speed compatible control section that outputs an operation control signal.

[Function] In the suspension alignment control device of the present invention described above, the vehicle speed corresponding control section of the control means causes the suspension stiffness adjustment means to weaken the longitudinal stiffness of the suspension as the vehicle speed increases, based on information from the brake sensor. Outputs an operation control signal. This makes it difficult for the front and rear suspension stiffness to adversely affect ride comfort during high-speed driving.

[Embodiment] Below, a suspension alignment control device as an embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram showing its configuration, and FIG. 2(b) is a sectional view taken along the ■b-nb arrow in FIG. 2(a), and FIG. 2(C) is a sectional view taken along the Uc-11c arrow in FIG. 2(a). figure,
Figure 3 is a schematic diagram showing an example of how the suspension is installed when viewed from the longitudinal direction of the vehicle, Figure 4 is a schematic plan view showing an example of how the suspension is installed, and Figure 5 is a schematic diagram showing an example of how the suspension is installed in the vehicle. A detailed view shown in the longitudinal direction, FIG. 6 is a plan view of the main part showing an example of mounting on the suspension, FIG. 7 is a side view of the main part showing an example of mounting on the suspension, and FIG. 8 is the control operation. 9 is a graph showing the stiffness setting characteristics by the control, FIG. 10 is a time chart showing the control operation when an external force is applied, and FIG. 11 is a graph showing the control time characteristics of the control when the external force is applied. Graph shown, 1st
2.13 are all sectional views showing other suspension rigidity adjusting means, and the same reference numerals indicate similar members in each figure.

As shown in FIG. 1, this suspension alignment control device includes a suspension bushing 1 with a stiffness adjustment mechanism as a suspension stiffness adjustment means, and a control means for controlling the suspension stiffness adjustment means (suspension bushing) 1. a controller 11,
A steering angle sensor 12b as a steering state sensor that can determine whether the vehicle is traveling straight or turning, a vehicle speed sensor 12c that can detect the running speed of the vehicle, and a vehicle speed sensor 12c that detects longitudinal acceleration acting on the vehicle. It is equipped with a longitudinal acceleration sensor 12d.

A suspension bushing with a rigidity adjustment mechanism 1 is provided at a portion where the suspension of an automobile is attached to the vehicle body.For example, the suspension bushing 1 is operated by a hydraulic control system 10 and can be controlled by hydraulic pressure to adjust the rigidity of the suspension from two directions. Possible examples include those shown in FIGS. 2(a) to 2(c). Note that this suspension bushing with a rigidity adjustment mechanism will also be referred to as a rigidity adjustment actuator l.

As shown in the figure, this suspension bushing 1 includes a case 2 attached to the vehicle body side, a shaft 3 attached to the suspension side, a rubber body 4 as an elastic support member that elastically supports this shaft 3 within the case 2, It has 6.

Of these, the rubber body 4 is located in the first direction [second direction] inside the case 2.
In the middle part in the vertical direction in Figure (a), both ends are fixed to the inner wall of the case 2, and spaces 7a and 7b as first oil chambers are formed on both sides of the rubber body 4. ing. Thereby, the rubber body 4 elastically supports the shaft 3 therein in the first direction.

Further, the rubber body 6 has both ends fixed to the inner wall of the case 5 in the second direction [in the middle of the left-right direction in FIG. Spaces 8a and 8b serving as second oil chambers are formed on both sides of the rubber body 6. Thereby, the rubber body 6 elastically supports the shaft 3 therein in the second direction.

Then, depending on the oil pressure supplied to the oil chambers 7a and 7b,
The support rigidity in the first direction changes, and the support rigidity in the second direction changes depending on the hydraulic pressure supplied into the oil chambers 8a, 8b.

Note that reference numeral 9 is a reinforcing material built into each of the rubber bodies 4 and 6, and this reinforcing material 9 ensures that the rubber bodies 4 and 6 have a certain tension (rigidity). Also, 20a-2
0d indicates each oil chamber 7a, 7b.

This is a supply/discharge port for hydraulic pressure to 8a and 8b.

These first and second oil chambers 7a, 71), 8
a, 8b have these oil chambers 7a, 7b.

A hydraulic control system 10 that controls the internal hydraulic pressure of the oil chambers 8a and 8b is connected to these oil chambers 7a and 7b.

8a, 8b and the hydraulic control system 10 constitute a rigidity adjustment mechanism IA that adjusts suspension rigidity.

In this example, the first direction [vertical direction C in Fig. 2 (a) is the longitudinal direction of the vehicle body, and the second direction [Fig.
a) It is installed so that the lateral direction inside is in the lateral direction of the vehicle body.

The hydraulic control system 10 is configured as shown in the upper part of FIG. 1, and in FIG.
Control valves connected to a to 20d; 11 a controller that outputs control signals to the control valves 10a and 10b; 1;
2 is a sensor group such as a vehicle speed sensor 12c connected to the controller 11; 13 is an orifice; 14 is an oil pump;
15° 18 is an accumulator, 16 is a relief valve,
17 is a one-way valve, and 19 is an oil reservoir.

Among the control valves 10a and 10b, the control valve 10a is a longitudinal rigidity control valve, and has oil chambers 7a and 7 arranged in parallel in the longitudinal direction of the vehicle body so as to adjust the longitudinal rigidity.
connected to b. Further, the control valve 10b is a lateral rigidity control valve, and is connected to oil chambers 8a and 8b arranged side by side in the lateral direction of the vehicle body so as to be able to adjust the lateral rigidity.

These control valves 10a and 10b are connected to the oil chamber 7.
an open state where the insides of a, 7b, 8a, 8b communicate with the accumulator 18 side, and oil chambers 7a, 7b.

A closed state in which the supply/discharge ports 20a, 20b, 20c, 20 of 8a, 8b are closed, and supply/discharge ports 2Qa, 20b.

The oil pressure chambers 20c and 20 are configured to be in a drain state in which the oil pressure in the oil chambers 7a, 7b, 8a, and 8b is discharged.

Therefore, if the control valves 10a and 10b are open, the oil driven by the oil pump 14 will flow to the valve 1.
6.17, the pressure is appropriately regulated and stored in the accumulator 18, and it is passed from the control valve 10a or fob to the supply/discharge port 20a.
, 20b or through the supply/discharge ports 20c, 20d, the oil chambers 7a, 7 of the actuator (suspension bushing) 1
b or 8a, 8b. The control valve 10a or 10b is connected to each oil chamber 7a, 7b or 8a.

When the inside of 8b reaches a predetermined pressure, it is closed, thereby keeping the pressure inside each oil chamber 7a, 7b or 8a, 8b constant at a predetermined level. Further, when the control valve 10a or 10b is set to the drain state, the oil chamber 7
The oil in a, 7b or 8a, 8b is drained and the oil chamber 7
a, 7b or 8a.

The pressure inside 8b is reduced.

The controller 11 controls the control valves 10a and 10b to one of the above states, and the controller 11 controls the control valve 10a based on information from various sensors (sensor group) 12 to adjust the suspension. The front and rear stiffness is adjusted by a vehicle speed corresponding control section 11b that controls the control valve 10a in accordance with the vehicle speed when traveling straight, based on information from the steering angle sensor 12b and the vehicle speed sensor 12c, and a vehicle speed corresponding control section 11b that controls the control valve 10a in accordance with the vehicle speed when traveling straight ahead. A control unit 11 for applying longitudinal acceleration temporarily adjusts the longitudinal stiffness of the suspension when the vehicle receives longitudinal acceleration due to road reaction force or the like while driving straight, based on information from the acceleration sensor 12d.
c is provided.

Although not shown, the controller 11 also includes control valves 10a and 10b depending on the braking state, for example.
A control section is also provided to control the front and rear rigidity.

The vehicle speed corresponding control section 11b controls the longitudinal stiffness of the suspension based on information from the vehicle speed sensor 12c so as to obtain the characteristics shown in FIG. 9. In other words, the front and rear stiffness of the suspension corresponding to the detected vehicle speed V is set, and the front and rear stiffness control valve 10 is set so that this stiffness is obtained.
A control signal is sent to a.

Therefore, up to a certain high speed vehicle speed, the longitudinal stiffness of the suspension is set so that it becomes smaller as the vehicle speed increases, and when the vehicle speed reaches a certain high speed, the stiffness is set to a constant small value.

Further, when the vehicle receives longitudinal acceleration as shown in FIG.
Adjust it high (hard) as shown in figure (b). This is because at high speeds, the longitudinal stiffness of the suspension is reduced by the vehicle speed corresponding control unit 11b, so when the vehicle receives longitudinal acceleration due to a protrusion on the negative surface, the influence of this input longitudinal acceleration remains on the suspension for a long time. This adversely affects ride comfort and handling feeling. For this reason, when the vehicle receives longitudinal acceleration, the longitudinal rigidity of the suspension is temporarily increased to improve its convergence.

However, these vehicle speed corresponding controls and longitudinal acceleration addition control are set to be performed only when the vehicle is traveling straight, based on information from the steering angle sensor 12b. This is to suppress changes in compliance as much as possible when turning, so that no discomfort occurs during steering.

Therefore, when the vehicle turns, the longitudinal stiffness of the suspension is maintained at a constant value of a certain degree. After the turn is completed, the above-mentioned vehicle speed corresponding control and longitudinal acceleration addition control are performed.

The above-mentioned suspension bushing with a rigidity adjustment mechanism is
It can be installed on various types of suspensions, but for example, when installing on a strut type suspension,
As shown in FIGS. 3 and 4, the shaft 3 can be installed vertically between the inner ends of the front and rear lower arms 24 and the vehicle body 26. Here, the installation direction of the actuator 1 is as follows.

As mentioned above, the shaft 3 is installed vertically. Direction] is installed facing the width direction of the vehicle.

In addition, in the figure, 21 is a wheel and 22 is a strut.

27 is a rubber bushing that rotatably supports the inner end of the strut 22 around the longitudinal axis of the vehicle, and 25 is a joining joint that connects the bushing 27 and the shaft 3 of the actuator 1.

Further, in detail, as shown in FIGS. 5 to 7.

configured. In the figure, the same reference numerals as those in FIGS. 3 and 4 indicate the same parts, 21a is a knuckle, 23 is a joint between the knuckle 21a and the outer end of the lower arm 24, and 28 is a spring.

Since the suspension alignment control device as an embodiment of the present invention is configured as described above, the suspension bushing 1 with a rigidity adjustment mechanism is controlled by the controller 11 to control the brake sensor 12a and the steering angle sensor 1.
Control valves 10a and 10b are controlled based on information from sensors 12 such as 2b.

That is, as shown in FIG. 8, control is started in conjunction with turning on the ignition, etc. First, each control parameter etc. is set to an initial value (step S1), and the vehicle speed sensor 12 is
The information (data) from the sensors 12 such as the steering angle sensor 12b and the steering angle sensor 12b is read (step S2).

Then, in step S3, it is determined whether the steering angle θ is approximately 0 based on information from the steering angle sensor 12b.

When the steering angle θ is not approximately O, that is, when the vehicle is turning, the longitudinal stiffness of the suspension and suspension is set to a constant value with a certain degree of magnitude, but when the steering angle θ is approximately O,
In other words, when driving straight, the front and rear stiffness of the suspension is controlled.

That is, in step S4, based on the information from the vehicle speed sensor lja, as shown in FIG. 9, longitudinal stiffness values corresponding to the vehicle speed ■ are determined. Then, in the following step S5, it is determined whether the magnitude of the longitudinal acceleration applied to the vehicle body (1 longitudinal G+) is larger than the threshold value G□, based on the information from the longitudinal acceleration sensor 12d. As this threshold value G1,
An appropriate value is set that can be a boundary value at which the longitudinal acceleration applied to the vehicle body due to uplift force received from unevenness of the road surface, etc. affects ride comfort.

When driving on a flat road surface, G1 around 1 is the normal threshold G
Since it does not become larger than 1, the process proceeds to step S6, and a drive command is issued to the drive section of the control valve log of the actuator 1 so that the longitudinal stiffness determined in step S4 is obtained.

That is, in order to obtain the set stiffness, an operation control signal corresponding to the set stiffness is sent from the controller 11 to the control valve 10a, and the longitudinal stiffness is adjusted by this oil pressure adjustment.

As a result, the longitudinal stiffness of the suspension decreases as the vehicle speed increases until a certain high vehicle speed is reached, and then takes a small constant value once the vehicle speed reaches a certain high speed.

Therefore, even if the vehicle speed increases, a soft and comfortable ride can be ensured.

In addition, when receiving force such as thrusting up from unevenness of the road surface, etc., if this is greater than a certain level, the threshold value G1 is around 1 G1.
becomes larger than □, and from step S5 to step S7
11, the control time Ts is first set according to the magnitude of the longitudinal acceleration detected by the longitudinal acceleration sensor 12d.

Then, in step S8, the control time Ts is changed to the previously calculated T.
It is determined whether Ts is larger than Ts', and if Ts is larger than Ts', in step S9, Ts is newly set to Ts'.
If Ts can be larger than Ts', then Ts'
In either case, the process proceeds to step SIO without updating. Through the control from step S8 to step S10, a control time Ts' corresponding to the maximum value of the longitudinal acceleration applied to the vehicle body is determined.

In step S10, it is determined whether or not the timer value T has started counting. If the timer T has not started counting, it is started in step sll.

Then, in step S12, it is determined whether or not the timer value T is larger than the above-mentioned control time Ts'. Between 1 and 2, adjust the rigidity to be high (that is, hard).

As a result, as shown in FIG. 10(a), when longitudinal acceleration is applied, the stiffness of the suspension increases for a set time Ts' from the stage when longitudinal acceleration exceeds a predetermined value, as shown in FIG. 10(b). Only the bar is adjusted below.

Therefore, the influence of longitudinal acceleration quickly converges, and the adverse effects of external forces on ride comfort and steering feeling are suppressed.

In addition to the above-mentioned control, the controller 11 also performs suspension rigidity adjustment including lateral rigidity, such as adjustment according to the braking state, for example.

Note that during a turn, the longitudinal stiffness of the suspension may be fixed to the magnitude at the start of the turn.

Further, the ff1f attitude of the suspension bush 1 is not limited to that of the above-described embodiment, and for example, it may be installed with the first direction facing the vehicle width direction and the second direction facing the vehicle length direction.

Further, the present suspension alignment control device may be one that can control the stiffness in one direction, and can be sufficiently applied using other types of suspension stiffness control means, and can also be applied to other types of suspensions.

For example, a suspension stiffness control means as shown in FIG. 12.13 may be used.

That is, as shown in FIG. 12.13, the suspension side shaft 43.
53 is elastically supported via elastic members 44.54, and oil chambers 45a and 53 are provided on both sides of the elastic members 44.54, respectively.
45b, 53a, and 53b are provided, and by adjusting the hydraulic pressure in the oil chamber, the rigidity in each direction (all horizontal directions in the drawing) can be adjusted. If the direction in which the rigidity can be adjusted in this manner is installed in the longitudinal direction of the vehicle body, the present device can be applied.

Furthermore, the control performed by the control means (controller) 11 may include various types of control in addition to the above-mentioned vehicle speed corresponding control, longitudinal acceleration control, and braking control.

[Effects of the Invention] As described in detail above, the suspension alignment control device of the present invention includes a suspension stiffness adjustment means that can adjust the longitudinal stiffness of a suspension provided in a vehicle, and a suspension stiffness adjustment means that controls the suspension stiffness adjustment means. and a vehicle speed sensor for detecting the traveling speed of the vehicle, and the control means adjusts the suspension stiffness so that the longitudinal stiffness of the suspension becomes weaker as the vehicle speed increases, based on information from the vehicle speed sensor. With a simple configuration that includes a vehicle speed responsive control unit that sends eight actuation control signals, the front and rear stiffness is adjusted in response to vehicle speed, ensuring a consistently good ride over a wide range of travel speeds from low to high speeds. This has the advantage of ensuring that

[Brief explanation of the drawing]

1 to 13 show a suspension alignment control device as an embodiment of the present invention, FIG. 1 is a block diagram showing its configuration, and FIG. Cross-sectional view as seen from Figure 2 (b
) is a sectional view taken along the line ■b-nb in Fig. 2(a), and Fig. 2(c
) is a cross-sectional view taken along the Elc-Uc arrow in Fig. 2(a), Fig. 3 is a schematic diagram showing an example of how it is installed on the suspension, looking in the longitudinal direction of the vehicle, and Fig. 4 shows an example of how it is installed on the suspension. A schematic plan view, Fig. 5 is a detailed view showing an example of mounting on the suspension when viewed from the longitudinal direction of the vehicle, Fig. 6 is a plan view of main parts showing an example of mounting on the suspension, and Fig. 7 is on the suspension. Fig. 8 is a flowchart showing its control operation, Fig. 9 is a graph showing the stiffness setting characteristics by the control, and Fig. 10 is a time chart showing the control operation when external force is applied. , Fig. 11 is a graph showing the control time characteristics of the control when external force is applied.
Each of the figures is a sectional view showing other suspension rigidity adjusting means. 1- (suspension bushing with rigidity adjustment mechanism or rigidity adjustment actuator), LA-rigidity adjustment mechanism, 2
- case, 3 - shaft, 4, 6 - rubber body as elastic support member, 5 - inner case, 7a. 7b--space as a first oil chamber, 8a, 8b-space as a second oil chamber, 9-reinforcing material, 10--hydraulic control system,
10a - front and rear rigidity control valve, 10b - lateral rigidity control valve, 11 - controller, 1lb - vehicle speed corresponding control section,
11c-control unit when adding longitudinal acceleration, 12-sensor group, 1
2 b - steering angle sensor, 12cm - vehicle speed sensor, 12
d - Longitudinal acceleration sensor, 13 - Orifice, 14 - Oil pump, 15° 18 - Accumulator, 16 - Relief valve, 17 - One-way valve, 19 - Oil reservoir, 20 a to 20 d - Supply/discharge port, 21 -wheels, 2
1a--knuckle, 22--strut, 23--joint, 24-lower arm, 25-joint joint,
26-body, 27-button, 28-spring, 42
．． 52-1-case, 44.54--elastic member, 45a
, 45b, 53a, 53b - one oil chamber.

Claims (1)

[Claims] A suspension stiffness adjusting means capable of adjusting the longitudinal stiffness of a suspension provided on the vehicle, a control means controlling the suspension stiffness adjusting means, and a vehicle speed sensor detecting the running speed of the vehicle, the control means , further comprising a vehicle speed corresponding control section that outputs an operation control signal to the suspension stiffness adjusting means so as to weaken the longitudinal stiffness of the suspension as the vehicle speed increases, based on information from the vehicle speed sensor.
Suspension alignment control device.