JPS6020618B2 - Air spring type shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air spring type shock absorber.

Conventional suspension systems (shock absorbers) for two-wheeled and four-wheeled vehicles
When using air springs, it is effective to obtain a good ride feeling due to the low spring constant against a relatively small acting load from below the spring, but it is effective when using air springs due to the relatively small acting load from below the spring. There is a certain position where the spring reaction force is insufficient against the Taikido from above.

In other words, this is not a problem during normal driving, but during circuit driving, sharp curves, sudden braking, etc., the large sprung mass acts directly on the suspension system as inertial force, and when driving on rough roads, the unsprung reaction force becomes extremely large. As a result, the vehicle body sank significantly and the running stability deteriorated.

In this case, it is possible to compensate to some extent by increasing the compression side damping force of the shock absorber, but this also causes the disadvantage that the riding feeling during normal driving is reduced (harder).

In order to solve these problems, the present invention shuts off a part of the air chamber depending on the sprung mass acceleration (inertia force) and piston displacement amount (compression amount) when a large input causes a compression action. We provide an air spring type shock absorber that increases the spring reaction force by reducing the effective volume, prevents the vehicle body from sinking too much, stabilizes the supporting force, and provides driving stability and a comfortable riding feeling. The purpose is to

0 Examples of the present invention will be described below based on the accompanying drawings.

In FIG. 1, 1 indicates a simple air spring type shock absorber body, and this shock absorber body 1 is as follows:
A piston 4 connected to a piston rod 3 is slidably installed inside an inner cylinder 2 connected to the sprung upper side (vehicle body side) 5, and the piston rod 3 is connected to the unsprung lower side (axle side) b. There is.

A piston 4 housed in the inner cylinder 2 has a sardine oil chamber 5.
a, 5b, and the piston 4 has oil chambers 5a, 5b.
An orifice 6 is formed into which the hole b is inserted.

A gas pressure chamber 8 is formed above the oil chamber 5a, into which air is injected at a predetermined pressure from an air inlet 7 provided at the upper end of the inner cylinder 2. 1 is a disc-shaped float plate 1 with a lotus hole 9 formed in the center.
0 is slidably installed inside.

The plate 10' is constantly pressed against a stopper ring 12 attached to the inner wall of the inner cylinder 2 by a spring 11 interposed between its upper end and the upper wall of the inner cylinder 2. An oil drain passage 13 is provided on one side of the plate 10.
The oil drain passage 13 is connected to the sub-pressure chamber 16 formed by the outer cylinder 15 on the outside through a through hole 14 formed in the side wall of the inner cylinder 2. .

Further, a through hole 17 is formed in the upper side wall of the inner cylinder 2 to communicate the gas pressure chamber 8 and the sub-pressure chamber 16. When the inner cylinder 2 sinks, the plate 10 relatively floats due to its inertia and is closed.

It should be noted that when the through hole 17 is closed, the oil draining through hole 14 is also closed at the same time, so that the auxiliary pressure chamber 16 is completely shut off. Next, the effect will be explained. First, when an impact force is applied to the shock absorber body 1 from the lower side b of the spring under normal running conditions of the wheel, the piston 4 moves through the piston rod 3 with a stroke S corresponding to the load.
At the same time, the hydraulic oil in the oil chamber 5a is compressed and flows out from the orifice 6 into the expanding oil chamber 5b, and at this time, the space volume is reduced by the volume corresponding to the amount of entry of the piston rod 3. The gas in the auxiliary pressure chamber 16, which is conveyed through the gas pressure chamber 8 and the through hole 17, is also compressed, and the impact force from the lower part of the spring b is converted into a compression reaction force in both chambers 8 and 16 as a spring reaction force. Absorb.

In this case, since the plate 10 does not move upward, the gas pressure chamber 8 and the auxiliary pressure chamber 16 are in a state of close communication. Note that the impact may damage the oil drain passage 13 and the through hole 1.
4 or through the through hole 17 into the auxiliary pressure chamber 16, the plate 10 does not move.
The oil is returned to the oil chamber 5a via the passage 13.

On the other hand, when a sudden impact force is applied to the shock absorber body 1 from the sprung mass a during circuit driving or sharp curve driving, the inner cylinder 2 and the external cylinder 15 integrated therewith are moved toward the unsprung mass b side by the impact force. At the same time, the plate 10 floats relatively upward into the inner cylinder 2 against the elastic force of the spring 11 due to its compression acceleration (inertia force).

As a result, the through hole 17 and the selection hole 14 that connect the secondary pressure chamber 16 and the gas pressure chamber 8 of the outer cylinder cylinder 15 are closed by the side wall of the plate 10, and the secondary pressure chamber 16 and the gas pressure chamber 8 are connected to each other. Lotus access is blocked.

Therefore, the effective volume of the gas pressure chamber is reduced by the sub-pressure chamber 16 formed in the outer cylinder 15 compared to the effective pressure chamber volume on the lower side b of the spring, and therefore, at this time. The compression reaction force opposing the relatively compressed piston 4, ie, the air spring reaction force, is larger on the upper side of the zero spring.

As a result, a predetermined spring reaction force is generated against a large sprung load, thereby absorbing the impact. The relationship between this spring reaction force is shown in Figure 2.

The characteristics shown by the solid line are caused by the action of the two pressure chambers 8 and 16,
5, and the dotted line indicates the case where only one pressure chamber 8 absorbs the load. Next, another embodiment will be explained based on FIG. , 8b, and the lower pressure chamber 8b is connected to the passage 13 of the plate 10 and the through hole 1.
It communicates with the auxiliary pressure chamber 16 via 4.

The gas pressure chamber 8b has an air inlet 7a and an auxiliary pressure chamber 1.
6 is injected with air at a predetermined pressure each time through an air injection port Tb. Therefore, when an impact from under the spring is input during normal running, the space volume is reduced by the amount of entry volume of the piston rod 3, so the gas pressure chambers 8a, 8b
At the same time, the gas in the auxiliary pressure chamber IS is also compressed, and the impact force is absorbed as zero spring reaction force.

In this case, the plate 10' rises to a position where the internal pressure of the gas pressure chamber 8a and the combined force of the spring 11 are balanced against the internal pressures of the gas pressure chamber 8b and the auxiliary pressure chamber 16, but in the range of normal running, the plate 10' Since the amount is small, the gas pressure chamber 3b and the auxiliary pressure chamber 16 maintain a flat state, thereby maintaining a soft riding feeling. On the other hand, when a sudden and large impact force is applied to the shock absorber body 1 from a or b when making a sharp curve or driving on a rough road, the piston stroke (S) becomes large and the plate 10 eventually moves into the through hole 14.
cut off.

For this reason, the effective volume of the gas pressure chamber is reduced by the amount of the sub-pressure chamber 16, thereby increasing the air spring reaction force to counter the large load. Figure 4 shows this relationship.
This shows that the spring reaction force increases after the stroke Sb.

Note that the one-dot chain line represents the characteristics when the pressure of the gas enclosed in the gas pressure chambers 8a, 8b is changed.
Moreover, if the plate 10 is brought into contact with the upper part of the inner cylinder 2 after closing the lotus passage hole 14, only the gas pressure chamber 8b will be left after that, and an even stronger spring reaction force will be obtained. As shown, there are three levels of spring characteristics.

As described above, the present invention has a spring reaction force with a low spring constant against a normal load from the lower side of the spring, and a large load from the lower side of the spring such as when driving on a rough road or a large load from the upper side of the spring. The spring reaction force can be automatically increased in response to input, which prevents the vehicle body from sinking too much even when there is a large input, and stabilizes the supporting force. This has the effect of exerting a strong spring reaction force and thus providing a comfortable riding feeling.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view showing the first embodiment of the present invention, Fig. 2 is its operating characteristic diagram, Fig. 3 is a longitudinal sectional front view of the second embodiment, and Figs. 4 and 5 are the same. FIG. 1...Air spring type shock absorber body, 2...
Inner cylinder, 3... Piston rod, 4... Piston, 5
a, 5b... Oil chamber, 6... Orifice, 7... Air inlet, 8... Gas pressure chamber, 9... Lotus through hole, 10
...Plate, 11...Spring, 12...Stopper ring, 13...Oil drain passage, 14...Lotus through hole,
15...Outer cylinder, 16...Sub-pressure chamber, 17.
...Through hole, a...Spring upper side, b...Spring lower side. Figure 1 Figure 2 Figure 4 Figure 3 Figure 5

Claims (1)

[Scope of Claims] 1. A piston connected to the axle side is slidably installed in an inner cylinder connected to the vehicle body side, and a gas pressure chamber is formed in the upper part of the oil chamber defined by the piston. , forming an auxiliary pressure chamber outside the gas pressure chamber, communicating the gas pressure chamber and the auxiliary pressure chamber through a through hole formed in the side wall of the inner cylinder, and sliding a plate on the inner cylinder; 1. An air spring type shock absorber, characterized in that the air spring type shock absorber is configured to be freely installed inside the cylinder and to close the through hole by displacing a plate relative to the inner cylinder. 2. Claim 1, wherein the plate is always biased toward the unsprung side via a spring.
Air spring type shock absorber as described in . 3. The air spring type shock absorber according to claim 1 or 2, wherein the gas pressure chamber is comprised of two pressure chambers vertically separated by a plate.