JPH02293212A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To improve the ride comfortableness for a suspension device for a twin car including an ACS-mounted car and a passive suspension mounted car by setting a pitch center of the front wheel of the ACS mounted car lower than that of the passive suspension mounted car. CONSTITUTION:A ground height h1 of a pitch center C of a front wheel 2F of an ACS mounted car 1 is set lower than the ground height of the roll center of the front wheel of a passive suspension mounted car, unillustrated. An upper arm 4 is disposed with an oscillation shaft inclined back and down with a relatively sharp inclination, and a lower arm 5 is disposed almost horizontal, while the pitch center C is set lower than a horizontal line l3 through a wheel center O of the front wheel 2F. In this constitution, shock at the time of running on a road protrusion can be reduced, and the ride comfortableness can be im proved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a suspension device for a vehicle, and particularly to a vehicle having a twin vehicle equipped with an ACS and a passive suspension.

(Prior Art) Conventionally, as a suspension device for a vehicle, a fluid cylinder is disposed between a vehicle body and each wheel, and the fluid cylinder is Active control suspension systems (ACS systems) are known that independently control the supply and discharge of fluid for each wheel to vary the suspension characteristics of a vehicle in accordance with driving conditions. This ACS
Vehicles equipped with the device, that is, ACS-equipped vehicles, have their weight supported only by the fluid pressure in the fluid cylinders, and the vehicle height is variable for each wheel, making it possible to prevent rolling and pitching of the vehicle body.

On the other hand, normal suspension devices, whether strut type or double wishbone type, are equipped with a shock absorber and a spring member, both of which damp vehicle body vibrations. A vehicle equipped with this suspension device is called a passive suspension equipped vehicle in contrast to the above-mentioned ACS equipped vehicle.

(Problem to be Solved by the Invention) Incidentally, when braking a vehicle, nose dive occurs due to inertia force. It is desirable to set the momentary center of movement of the front wheels relative to the vehicle body at a higher position behind the front wheels. However, if the pitch center of the front wheels is set too high, when the front wheels go over road bumps,
While the direction of the load acting on the front wheels is rearward and upward, the front wheels are displaced forward and upward around the pitch center, and a large shock is generated due to the gap between the direction of displacement of the front wheels and the direction of the load. , the ride quality becomes worse.

For this reason, in conventional vehicles, it is common to set the pitch center of the front wheels at a slightly higher position than the wheel center of the front wheels. The current situation is that this is not enough to alleviate the shock.

The present invention has been made in view of the above, and its purpose is to focus on the fact that nose dive of the vehicle body can be prevented by controlling the supply and discharge of fluid to the fluid cylinder, especially in the case of vehicles equipped with ACS. The pitch center of the front wheels of this ACS-equipped vehicle is appropriately set to effectively alleviate the shock caused when the vehicle runs over a road bump, thereby improving riding comfort.

(Means for solving the problem) In order to achieve the above object, the invention of claim (1):
A suspension device equipped with an ACS equipped vehicle that can change suspension characteristics by controlling the supply and discharge of fluid in a fluid cylinder arranged between a vehicle body and each wheel as a twin vehicle, and a shock absorber and a spring member. The pitch center of the front wheels of the ACS equipped vehicle is set at a lower position than that of the passive suspension equipped vehicle. Here, twin vehicles refer to vehicles of the same type that have almost the same basic dimensions and framework layout, and are given the same name, and are also referred to as parent-child vehicles.

In addition, the invention described in claim (a) provides a vehicle equipped with an ACS device capable of changing suspension characteristics by controlling the supply and discharge of fluid in a fluid cylinder disposed between a vehicle body and each wheel. The pitch center of the vehicle is set at a position lower than the horizontal line passing through the wheel center of the front wheels.

(Function) With the above configuration, in the case of a twin vehicle equipped with ACS, nose dive during braking can be prevented by controlling the supply and discharge of fluid in the fluid cylinder, and Since the pitch center of the front wheels is set at a lower position than that of a vehicle equipped with passive access, the front wheels are displaced rearward and upward in the same direction as the load when passing over a road bump, effectively suppressing shock.

Further, in the invention described in claim (2), the ACS equipped vehicle is
Although it does not necessarily constitute a twin vehicle with a vehicle equipped with a passive suspension, since the pitch center of the front wheels is set at a lower position than the horizontal line passing through the wheel center of the front wheels, Similarly, by controlling the supply and discharge of the fluid in the fluid cylinder, it is possible to effectively suppress shock when the vehicle runs over a road bump while preventing nose dive.

(Example) Embodiments of the present invention will be described below based on the drawings.

Figures 1 and 2 show an ACS-equipped vehicle equipped with an ACS device that can change suspension characteristics, and Figures 3 and 4 show a passive suspension-equipped vehicle equipped with a normal double wishbone suspension device. show. These two types of vehicles are mutually called twin vehicles.

In Figures 1 and 2, 1 is the vehicle body, 2F is the front wheel,
2R is a rear wheel, and each wheel 2F, 2R is rotatably supported by a wheel support member 3, respectively. The upper and lower parts of the wheel support member 3 are connected to a strength member (such as a frame) of the vehicle body 1 via an upper arm 4 or a lower arm 5, respectively.

A fluid cylinder 6 is arranged between the vehicle body 1 and each wheel 2F, 2R, and each fluid cylinder 6 is
A hydraulic chamber 6C is defined by a piston 6b fitted into the cylinder body 6a.

The upper end of the piston rod 6d connected to the piston 6b is connected to the vehicle body 1, while the cylinder main body 6a
is connected to a member (lower arm 5 or wheel support member 3) on the wheels 2F, 2R side.

Gas springs 8 are connected to each of the hydraulic pressure chambers 6C via communication passages 7. Each gas spring 8 is divided into a gas chamber 8b and a hydraulic chamber 8c by a diaphragm 8a,
The hydraulic chamber 8C communicates with the hydraulic chamber 6C of the fluid cylinder 6.

Further, 11 is a hydraulic pump, and 12 is a flow control valve interposed in a hydraulic passage 13 that communicates the hydraulic pump 11 and each fluid cylinder 6. It has the function of supplying and discharging fluid (oil) and adjusting the flow rate. 14 is a main pressure sensor that detects the discharge pressure of the hydraulic pump 11, 15 is a cylinder pressure sensor that detects the hydraulic pressure in the hydraulic chamber 6c of each fluid cylinder 6, and 16 is the vehicle height of the corresponding wheels 2F, 2H ( 17 is a vertical acceleration sensor that detects the vertical acceleration of the vehicle body (spring mass acceleration of wheels 2F and 2R), and the detection signals of these sensors 14 to 17 are sent to each internal CPU. etc., is input to the controller 19 having the following. The controller 19 determines the operating state based on this input signal, and changes the flow rate control valves 12 according to the result of the determination to variably control the suspension characteristics.

On the other hand, in the case of the passive suspension equipped vehicle shown in FIGS. 3 and 4, shock absorbers 21 are provided between the vehicle body 1 and each wheel 2F, 2R to damp the vertical vibration of each wheel 2F, 2H. The upper end of the shock absorber 21 is connected to the vehicle body 1, and the lower end is connected to a member (lower arm 5 or wheel support member 3) on the wheels 2F, 2R side. Further, a coil spring 22 as a spring member is arranged on the outer periphery of the shock absorber 21.

Here, in the case of the example, the suspension system of the ACS-equipped vehicle is based on a double wishbone type suspension similar to the suspension system of the passive suspension-equipped vehicle, and in the case of this type of suspension system, the pitch of the front wheels is The center C is the swing axis of the upper arm 4 (
For details, see the extension)! Swing wheel 9 of Q1 and lower arm 5
This is the intersection with 2.

As a feature of the present invention, the front wheel 2F of the ACS equipped vehicle
The ground clearance h1 of the pitch center C of the vehicle is set lower than the ground clearance h2 of the roll center C of the front wheel 2F of the passive suspension equipped vehicle. In other words, for vehicles equipped with passive suspension,
The swinging wheel 9l of the upper arm 4 is tilted rearward and downward, and the swinging axis 2 of the lower arm 5 is tilted rearward and upward.
It is located at a higher position than the horizontal line 93 passing through the wheel center O of F. On the other hand, in the case of an ACS-equipped vehicle, the swing axis 91 of the upper arm 4 is provided with a relatively steep inclination and is inclined rearward and downward, and the extension line 92 of the lower arm 5
is provided substantially horizontally, so that the pitch center C of the front wheel 2F is aligned with the horizontal line 93 passing through the wheel center O of the front wheel 2F.
It is located at a lower position.

Therefore, in the above embodiment, the AC of the twin cars is
In the case of the S-equipped vehicle, the pitch center C of the front wheel 2F is set lower than the horizontal line 93 passing through the wheel center O of the front wheel 2F, unlike the case of a passive suspension equipped vehicle, so that the front wheel 2F can overcome the road bump. At this time, the front wheel 2F is momentarily displaced rearward and upward in the same direction as the impact load acting direction, centering on the wheel center O, so that the shock can be effectively absorbed and alleviated, and the riding comfort can be improved.

Here, if the ground clearance h1 of the pitch center C of the front wheel 2F is low, the load acting upward on the wheel center O of the front wheel 2F during braking becomes large, and there is a strong tendency to increase nose dive. In the case of a vehicle equipped with ACS, one controller controls the supply and discharge of fluid to each fluid cylinder 6 for each wheel 2F and 2R, almost unaffected by the magnitude of the upward load acting on the wheel center O of the front wheel 2F. By controlling and adjusting the vehicle height, the vehicle body 1 can be kept substantially horizontal and nose dive can be prevented.

It should be noted that the present invention is not limited to the above embodiments, but includes various other modifications.

For example, in the above embodiment, a case has been described in which the suspension devices of the ACS-equipped vehicle and the passive suspension-equipped vehicle as twin vehicles are both of the double wishbone type. It can also be applied when using a suspension device. In addition, the suspension device for the front wheels and the suspension device for the rear wheels, or the suspension device for the ACS equipped vehicle and the suspension device for the passive suspension equipped vehicle are not limited to the case where the same type is used as in the example, but are different. You may also use a model.

In short, the pitch center of the front wheel 2F of the ACS-equipped twin vehicle should be set at a lower position than that of the passive suspension-equipped vehicle.

(Effects of the Invention) As described above, according to the vehicle suspension device of the present invention, especially in the case of a vehicle equipped with ACS, the ACS device prevents nose dive during braking, while the front wheels are loaded with load when passing over a road bump. Since the shock can be effectively alleviated by displacing backward and upward in the same direction as the direction of travel, the riding comfort can be improved.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic diagram showing the overall configuration of an ACS-equipped vehicle, FIG. Figure 3 is a diagram equivalent to Figure 1 for a vehicle equipped with passive suspension.
FIG. 4 is also a diagram corresponding to FIG. 2. DESCRIPTION OF SYMBOLS 1... Vehicle body, 2F... Front wheel, 2R... Rear wheel, 6... Fluid cylinder, 21... Shock absorber, 22... Coil spring (spring member), C... Pitch center , O...Wheel center. Figure 2 Figure 4

Claims (2)

[Claims] (1) As a twin vehicle, it is equipped with an ACS equipped vehicle whose suspension characteristics can be changed by controlling the supply and discharge of fluid in a fluid cylinder disposed between the vehicle body and each wheel, a shock absorber, and a spring member. AC
A vehicle suspension device characterized in that the pitch center of the front wheels of an S-equipped vehicle is set at a lower position than that of a passive suspension-equipped vehicle. (2) In vehicles equipped with an ACS device that can change suspension characteristics by controlling the supply and discharge of fluid in fluid cylinders located between the vehicle body and each wheel, the pitch center of the front wheels is the wheel center of the front wheels. A vehicle suspension device characterized by being set at a position lower than a horizontal line passing through the vehicle.