JPH02293209A - Suspension device for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 control fluid supply and discharge (supply and discharge) for each wheel independently to vary the suspension characteristics of a vehicle in accordance with driving conditions. This ACS
Vehicles equipped with this system, 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, so posture control is performed to prevent vehicle body rolling, pitching, etc. be able to.

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) By the way, when mounting a fluid cylinder on the vehicle body in the above-mentioned ACS equipped vehicle, a mount rubber is used in the same way as when attaching a shock absorber etc. to the vehicle body in a passive suspension equipped vehicle. How to set the hardness of the mount rubber is an important issue in achieving both riding comfort and posture control.

The present invention has been made in view of the above, and its purpose is to appropriately adjust the hardness of the mount rubber of the ACS-equipped vehicle, especially in a twin vehicle that has an ACS-equipped vehicle and a passive suspension-equipped vehicle. By setting this, it is possible to effectively achieve both riding comfort and posture control.

(Means for solving the problem) In order to achieve the above object, the invention described in 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 hardness of the mount rubber of the ACS equipped vehicle is set differently from that of the passive suspension equipped vehicle.

Here, as a more specific aspect of setting the hardness of the mount rubber, the invention described in claim (2) provides an ASC
Set the hardness of the mount rubber of the equipped vehicle to be harder than that of the vehicle equipped with passive suspension. Further, in the invention described in claim (3), the hardness of the mount rubber of the ASC-equipped vehicle is set to be softer than that of the passive suspension-equipped vehicle. Incidentally, twin cars 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 called parent-child cars.

(Function) With the above configuration, in a car equipped with ASC, if the hardness of the mount rubber is set to be hard, the vertical displacement of the mount rubber will be reduced, so the fluid can flow to the fluid cylinder without being affected by this vertical displacement. It is possible to reliably control the attitude of the vehicle body by supplying and discharging the air in a predetermined manner.

Moreover, since vibrations on the wheel side can be absorbed by controlling the supply and discharge of fluid to the fluid cylinder, the riding comfort can be improved regardless of the hardness of the mount rubber.

On the other hand, in a vehicle equipped with ACS, if the hardness of the mount rubber is set to be soft, high-frequency vibrations on the wheel side where the vibration absorption effect cannot be obtained by controlling the supply and discharge of fluid to the fluid cylinder are absorbed by the mount rubber. Therefore, the riding comfort can be improved. Furthermore, changes in the vehicle body posture due to the vertical displacement of the mount rubber can be prevented by controlling the posture by controlling the supply and discharge of fluid to and from the fluid cylinder.

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

FIG. 2 shows an ACS-equipped vehicle equipped with an ACS device that can change suspension characteristics, and FIG. 4 shows a passive suspension-equipped vehicle equipped with a normal strut type suspension device. These two types of vehicles are mutually called twin vehicles.

In FIG. 2, 1 is a vehicle body, 2F is a front wheel, and 2R is a rear wheel. Fluid cylinders 3 are arranged between the vehicle body 1 and the front wheel 2I' and between the vehicle body 1 and the rear wheel 2R. ing. Each fluid cylinder 3 has a hydraulic chamber 3c defined by a piston 3b fitted into a cylinder body 3a.

The upper end of the piston rod 3d connected to the piston 3b is connected to the vehicle body 1, and the cylinder body 3a is connected to each wheel 2.
It is connected to F and 2R.

A gas spring 5 is connected to the hydraulic pressure chamber 3c of each of the fluid cylinders 3 through a communication path 4. Each gas spring 5 is divided into a gas chamber 5f and a hydraulic chamber 5g by a diaphragm 5e, and the hydraulic chamber 5g communicates with the hydraulic chamber 3C of the fluid cylinder 3.

Further, 8 is a hydraulic bomb, and 9 is a flow control valve interposed in a hydraulic passage 10 that communicates the hydraulic bomb 8 and each fluid cylinder 3. It has the function of supplying and discharging fluid (oil) and adjusting the flow rate.

Furthermore, 12 is a main pressure sensor that detects the oil discharge pressure of the hydraulic pump 8 (more specifically, the pressure of oil stored in accumulators 22a and 22b, which will be described later), and 13 is a main pressure sensor for each fluid cylinder 3.
a cylinder pressure sensor 14 for detecting the hydraulic pressure in the hydraulic pressure chamber 3C;
is the corresponding wheel 2F. The vehicle height sensor 15 detects the vehicle height (cylinder stroke amount) of 2R, and the vehicle height sensor 15 detects the vehicle vertical acceleration (
Wheel 2F. 2R (spring mass acceleration)), and detection signals from these sensors 12 to 15 are each input to a controller 19 having an internal CPU, etc., and are used for variable control of suspension characteristics.

Next, a hydraulic circuit for controlling supply and discharge of fluid to the fluid cylinder 3 is shown in FIG. In the figure, a hydraulic bomb 8 is a variable displacement swash plate piston pump, and a hydraulic bomb 21 for a power steering device is driven by a drive source 20.
are connected in two series. The hydraulic passage 10 connected to the hydraulic pump 8 includes three accumulators 22a, 22.
a, 22a are connected in the same place, and
At the connection point, the hydraulic passage 10 is branched into a front wheel side passage LOP and a rear wheel side passage 10R. Furthermore, the front wheel side passage 10F has a left front wheel side passage 10FL and a right front wheel side passage 10PR.
Each passage 10PL, 10PR has a hydraulic pressure chamber 3c of a corresponding wheel fluid cylinder 3FL, 3FR.
are being communicated. On the other hand, one accumulator 22b is connected to the rear wheel side passage 10R, and
On the downstream side, left rear wheel side passage 10RL and right rear wheel side passage 10
RR, and each passage 10RL, IORR has a corresponding wheel fluid cylinder 3RL. The hydraulic pressure chambers 3C of 3RR are communicated with each other.

Each of the above fluid cylinders 3PL. 3FR. 3RL,
Gas springs 5PL, 5PR connected to 3RR,
5RL. Each of the 5RRs is specifically provided with a plurality of pieces (four pieces in the figure), and these gas springs 5a, 5b
．． 5c and 5d are hydraulic pressure chambers 3C of the corresponding fluid cylinders 3;
are connected in parallel to each other via a communication path 4. Further, each of the gas springs 5a to 5d is provided with an orifice 25 interposed in the branching part of the communication path 4, and the damping action of each orifice 25 and the buffering action of the gas sealed in the gas chamber 5r are It has come to demonstrate both. A damping force switching valve 26 for adjusting the passage area of the communication path 4 is interposed in the communication path 4 between the first gas spring 5a and the second gas spring 5b. , has two positions: an open position where the communicating passage 4 is opened, and a constricted position where the passage area is significantly narrowed.

Further, an unload valve 27 and a flow rate control well 28 are connected to the hydraulic passage 10 on the upstream side of the accumulator 22a. The unload valve 27 transfers the pressure oil discharged from the hydraulic bomb 8 to the swash plate operating cylinder 8a of the hydraulic bomb 8.
It has an introduction position where the oil is introduced to reduce the oil discharge amount of the hydraulic bomb 8, and a discharge position where the pressure oil in the cylinder 8a is discharged, and the oil discharge pressure of the hydraulic pump 8 is set to a predetermined upper limit oil discharge pressure ( It is designed to switch from the discharge position to the introduction position when the discharge pressure exceeds 160±10kgf/cI#), and maintain this state until it falls below a predetermined lower limit discharge pressure (120±10kgf/cshi). to keep the oil discharge pressure of the hydraulic bomb 8 within a predetermined range (120 to 160 kgf/cj
) has the function of holding and controlling.

The flow rate control valve 28 has an introduction position where pressure oil from the hydraulic pump 8 is introduced into the swash plate operating cylinder 8a of the hydraulic bomb 8 via the unload valve 27, and an introduction position where the pressure oil in the cylinder 8a is unloaded. and a discharge position for discharging from the valve 27 to the reserve tank 29, and when the oil discharge pressure of the hydraulic bomb 8 is maintained within a predetermined range by the unload valve 27, the throttle 30 arrangement part of the hydraulic pressure passage 10 It has a function of keeping the differential pressure between the upstream and downstream sides constant and controlling the discharge amount of the hydraulic pump 8 to keep it constant. Therefore, each fluid cylinder 3
The oil is supplied to the oil stored in the accumulators 22a and 22b (
This oil pressure is called main pressure).

On the other hand, on the downstream side of the accumulator 22a of the hydraulic passage 10, there are four flow control valves 9, 9, . . . corresponding to the four wheels of the vehicle.
is provided. Hereinafter, since the configuration of the parts corresponding to each wheel is the same, only the left front wheel side will be explained, and the explanation of the others will be omitted. That is, the flow rate control valve 9 is connected to a first switching valve 35 provided in the left front wheel side passage 10PL of the hydraulic pressure passage 10 and a low pressure line 36 that discharges oil from the left front wheel side passage 10PL to the reserve tank 29. and a second switching valve 37 provided therein. Each of the switching valves 35 and 37 has two positions, an open position and a closed position, and incorporates a differential pressure valve that maintains the hydraulic pressure at a predetermined value in the open position.

Further, a pilot pressure responsive check valve 38 is interposed in the left front wheel side passage 10PL between the first switching valve 35 and the fluid cylinder 3. The check valve 38 receives the hydraulic pressure (that is, main pressure) in the hydraulic pressure passage 10 upstream of the proportional flow control valve 9 (first switching valve 35) as a pilot pressure through a pilot line 39, and this pilot pressure reaches 40 kgf. /cd or less. In other words, the main pressure is 40 kg f
/cd or more, it is possible to supply pressure oil to the fluid cylinder 3 and to discharge the oil in the fluid cylinder 3.

In addition, in FIG. 3, 41 is the accumulator 2 of the hydraulic pressure passage 10.
This is a fail-safe valve installed in the communication path 42 that communicates the downstream side of the accumulator 2a and the low-pressure line 36, and is switched to the open position in the event of a control failure, returning the oil stored in the accumulators 22a and 22b to the reserve tank 29, and maintaining the high-pressure state. It has a function to release the .

Further, reference numeral 43 denotes a throttle provided in the pilot line 39, which has a function of delaying the closing of the check valve 38 when the fail-safe valve 41 is opened. 44 is the hydraulic pressure chamber 3C of each fluid cylinder 3 PL, 3PR on the front wheel side.
This is a relief valve that opens when the oil pressure of the hydraulic pressure chamber 3C increases abnormally and returns the oil in the hydraulic pressure chamber 3C to the low pressure line 36. A return accumulator 45 is connected to the low pressure line 36 and performs a pressure accumulating action when oil is discharged from the fluid cylinder 3.

Next, the assembly structure etc. of the fluid cylinder 3 and the gas spring 5 will be explained as follows.
and gas spring 5PR will be explained as an example.

That is, in FIG. 1, the lower part of the cylinder body 3a of the fluid cylinder 3PH is connected to the wheel (front wheel) 2PR via a wheel support 51, while the upper end of the piston rod 3d is connected to the vehicle body 1 via a mount rubber 52. has been done. Mount rubber 5 of piston rod 3d
2. Between the mounting part and the cylinder body 3a, from the top,
A support member 53 that supports the gas spring 5FR at its upper end, and a bump stopper 54 that restricts the bump of the wheel 2PR are provided. The above bump stopper 54
When the cylinder body 3a of the fluid cylinder 3FR rises with the bump of the wheel 2PR, the bump stopper 54 (; is, Cylinder body 3a
A cover 55 that covers the upper part of is integrally formed.

Further, a communication passage 4 communicating with a hydraulic pressure chamber 3c (see FIG. 2) in the fluid cylinder is formed in the piston rod 3d, and the communication passage 4 is connected to a branch communication passage formed in the support member 53. It communicates with the hydraulic pressure chamber 5g of the gas spring 5PR through 4a, and the above-mentioned throttle 43 is connected to the branch communication path 4a.
is provided.

A plurality of gas springs 5a to 5d as gas springs 5FR
(see FIG. 4) are each supported by a support member 53 on the vehicle body side of the outer periphery of the fluid cylinder 3FR.

On the other hand, in the case of a vehicle equipped with passive suspension as shown in Fig. 4, the vehicle body 1
A strut 61 is installed between the and each wheel 2F, 2R.
is installed. As shown in detail in FIG. 5, the strut 61 is connected to the wheel 2F. It consists of a shock absorber 62 having a function of damping vertical vibration of 2H, and a coil spring 63 as a spring member disposed on the upper outer periphery of the shock absorber 62. The lower part of the cylinder body 62a of the shock absorber 62 is connected to the wheels 2F and 2R via a wheel support (not shown).
The upper end of the piston port 62b of the shock absorber 62 is connected to the vehicle body 1 via a mount rubber 64. The upper end of the coil spring 63 is connected to an upper spring seat 65 attached to the piston rod 62b.
In addition, the lower ends are supported by lower spring seats 66 attached to the cylinder body 62a. In the case of this strut type suspension device, the vehicle weight is supported by the hydraulic pressure (hydraulic pressure) within the cylinder body 62a of the shock absorber 62 and the spring reaction force of the coil spring 63. In FIG. 5, reference numeral 67 is a bump stopper that comes into contact with the upper end surface of the cylinder body 62a to restrict the bump of the wheel when the wheel bumps.
A bellows-shaped cover 68 that covers the top of the bottom absorber 62 is integrally formed on the bottom.

As a feature of the present invention, the mount rubber 52 (see Fig. 1) in the suspension device of an ACS equipped vehicle is
The hardness (specifically, the hardness of the rubber pushers 52a and 64a) is set to be different from that of the mount rubber 64 (see FIG. 5) in the suspension system of a vehicle equipped with a passive suspension.

That is, as a first aspect, the hardness of the mount rubber 52 of the ACS equipped vehicle is set to be harder than that of the mount rubber 64 of the passive suspension equipped vehicle. Further, as a second aspect, the hardness of the mount rubber 52 of the ACS equipped vehicle is set to be softer than that of the mount rubber 64 of the passive suspension equipped vehicle. Figure 6 is a load-deflection diagram of such a mount rubber. In the figure, line A is the load-deflection curve of mount rubber 64 for a vehicle equipped with passive suspension, and line B is a curve for the rigid mount of a vehicle equipped with ACS. Rubber
Line C shows the load-deflection curve of the soft mount rubber 52 of the ACS-equipped vehicle.

Next, to explain the operation and effect of the above embodiment, in the ASC equipped vehicle of the twin vehicles, the hardness of the mount rubber 52 is higher than the normal hardness, that is, that of the mount rubber 64 of the passive suspension equipped vehicle. If it is set hard, the vertical displacement of the mount rubber 52 is small even when a load is applied from the wheels 2F, 2R side. For this reason,
In the ACS device, when controlling the attitude of the vehicle body 1 by controlling the supply and discharge of fluid to the fluid cylinder 3, the attitude control is reliably performed as specified without being affected by the vertical displacement of the mount rubber 52. be able to.

In addition, vibrations in the low frequency range on the wheels 2F and 2R sides can be absorbed by controlling the supply and discharge of fluid to the fluid cylinder 3, so the riding comfort can be improved despite the increased hardness of the mount rubber 52. can do.

On the other hand, in vehicles equipped with ACS, the mount rubber 52
If the hardness of the mount rubber 52 is set to be softer than normal hardness, the mount rubber 52 absorbs vibrations in the high frequency region of the wheels 2F and 2R, where the vibration absorption effect by controlling the supply and discharge of fluid to the fluid cylinder 3 cannot be obtained. Since it can be absorbed by Moreover,
Changes in the vehicle body posture due to the vertical displacement of the mount rubber 52 can be prevented by posture control by the ACS device.

Here, whether the hardness of the mount rubber 52 of the ACS-equipped vehicle is set to be hard or soft depends on whether the attitude control by the ACS device is performed in the low frequency region of wheel vibration or the riding comfort in the high frequency region of wheel vibration. This will be decided depending on whether or not you place importance on it.

In short, the present invention provides mount rubber 5 for ACS equipped vehicles.
What is necessary is to set the hardness of No. 2 to be different from the hardness of the mount rubber 64 of a vehicle equipped with a passive suspension.

(Effects of the Invention) As described above, according to the vehicle suspension device of the present invention, by setting the hardness of the mount rubber of the ACS equipped vehicle to be different from that of the passive suspension equipped vehicle,
It is possible to effectively achieve both riding comfort and posture control.

As one aspect of this, if the hardness of the mount rubber of an ACS-equipped vehicle is set to be harder than that of a passive suspension-equipped vehicle, the attitude control by the ACS device can be performed as specified without being affected by the vertical displacement of the mount rubber. This can be done reliably, and moreover, the ACS device can absorb vibrations on the wheel side and maintain good riding comfort.

In addition, as another aspect, if the hardness of the mount rubber of an ACS-equipped vehicle is set to be softer than that of a passive suspension-equipped vehicle, the mount rubber absorbs high-frequency vibrations on the wheel side to improve ride comfort. Moreover, the ACS device can prevent changes in the vehicle body posture due to vertical displacement of the mount rubber.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a partially cutaway front view of a suspension device (ACS device) of an ACS-equipped vehicle, and FIG. 2 shows a schematic configuration of the ACS-equipped vehicle. Schematic diagram, Figure 3 is a hydraulic circuit diagram of the ACS device, Figure 4 is a schematic diagram showing the general configuration of a vehicle equipped with a passive suspension, and Figure 5 is a longitudinal side view showing the structure of the upper part of the strut of the strut type suspension device. It is. FIG. 6 is a load-deflection diagram of the mount rubber. 1... Vehicle body, 2F... Front wheel, 2R... Rear wheel, 3 (3PL. 3PR. 3RL, 3RR)
...Fluid cylinder, 52...Mount rubber for vehicles equipped with ACS 62...Shock absorber, 63...Spring member, 64...Mount rubber bamboo for vehicles equipped with passive suspension 1J Fig. 64a Fig.

Claims (3)

[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 hardness of the mount rubber of an S-equipped vehicle is set differently from that of a passive suspension-equipped vehicle. (2) The suspension device for a vehicle according to claim (1), wherein the hardness of the mount rubber of the ACS equipped vehicle is set to be harder than that of the passive suspension equipped vehicle. (3) The suspension device for a vehicle according to claim (1), wherein the hardness of the mount rubber of the ACS-equipped vehicle is set to be softer than that of the passive suspension-equipped vehicle.