JPS5881242A - Damping force adjustable oil-pressure damper - Google Patents

Abstract

PURPOSE:To have possibility to change the damping force to a great extent, by furnishing a variable orifice in parallel with an expansion side and a compression side damping valve, by installing another expansion side and another compression side damping valve in series thereto, and by shortcircuiting the oil line connecting the two expansion side damping valves with the compression side damping valves selectively to the oil chamber using a selector valve. CONSTITUTION:At a piston 2 is parallelly installed a rotary valve 8 which constitutes No.1 expansion side and No.1 compression side damping valve 4, 5 and a variable orifice 13. A selector valve 16 and No.2 expansion side 17 and No.2 compression side 18 damping valve are arranged inside the piston nut 15 to be fitted on the piston 2. A selector valve 16 is to shortcircuit the oil line between No.1 damping valve 4, 5 and No.2 damping valves 17, 18 selectively to the oil chamber B by opening or closing a by-pass port 20. Thereby a comparatively low damping characteristic is obtained when the selector valve 16 and variable orifice 13 are open, and a comparatively high damping characteristic when the variable orifice 13 is closed. Further when the selector valve 16 is closed, a high damping characteristic is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber whose damping force can be freely adjusted.

The damping characteristics required for a vehicle vary widely depending on driving conditions.

For example, Japanese Unexamined Patent Publication No. 117486/1986 discloses a mechanism that can freely adjust such damping characteristics, which will be explained with reference to FIG.

A piston 2 is slidably housed inside the cylinder 1, and oil chambers A and B are defined above and below the piston 2.
A free piston 3 housed below defines a gas chamber C.

An overwhelming damping valve 4.5 is installed in parallel with the piston 2 on the expansion side, and when the piston rod 6 is in operation on the expansion side, the expansion side damping valve 4 is installed.
provides resistance to the hydraulic oil flowing from the contracting oil chamber A to the expanding oil chamber B, and on the other hand, during pressure side operation where the piston rod 6 enters, the overwhelming damping valve 5 provides resistance to the hydraulic oil flowing from the oil chambers B and A to the oil chamber A. and generate damping force respectively.

The gas chamber C partitioned off by the free piston 3 compensates for the inflow and outflow of oil corresponding to the intrusion volume of the piston rod 6 under overwhelming conditions.

\The piston rod 6 is provided with a rotary valve 8 between a small hole 9 at the tip of an operating rod 7 that passes through the piston rod 6, and a through hole 11 of a passage 10 that bypasses the piston part from the oil chamber A to the 8. This small hole 9
This forms a variable orifice that connects oil chambers A and B.

A rotary solenoid 13 provided at the protruding end of the operating rod 7
When the rod 7 is driven, the rotary valve 8 closes the through hole 11 and the through hole 11 is opened by the rotation of the rotary valve 8.

Therefore, when a soft reduction characteristic is desired, such as when driving in the city, by opening the rotary valve 8, the oil chambers A and B are connected through the passage 10, which has b orifices in addition to the expansion side and compression side damping valves 4 and 5. As a result, the flow resistance of hydraulic oil is reduced and the damping force is reduced.

On the other hand, when you want to obtain hard damping characteristics to ensure vehicle handling stability at high speeds, use the rotor/bow.

If you close Repulp 8, 1. - Relatively high damping force is generated only by the expansion side and compression side damping valves 4 and 5.

In this way, the damping force can be switched.
As shown in Fig. 2, by simply opening and closing the orifice of the rotary valve 8, the effectiveness of the orifice remains constant, even if the damping characteristics in the low piston speed range, where the A-refice flow rate occupies a large proportion, are greatly changed. In the medium and high speed range, the damping characteristics exist almost only in the rebound side and compression side damping valves 4.5, and there is a drawback in that very large changes cannot be obtained.

An object of the present invention is to provide a hydraulic shock absorber whose damping characteristics can be adjusted from a low piston speed range to a high speed range.

The present invention provides a variable orifice in parallel with the first expansion side and compression side damping valves, further provides a second expansion side and compression side damping valve in series with these, and an oil path between the first and second damping valves. is selectively short-circuited with the oil chamber by a switching valve, and when the switching valve and variable orifice are open, the first damping valve and the variable orifice in parallel have relatively low damping characteristics, and the variable orifice has a relatively low damping characteristic. When the switching valve is closed, a relatively high damping characteristic is obtained only by the first damping valve, and when the switching valve is closed, a high damping characteristic is obtained by the second damping valve in series with the first damping valve. .

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

In FIGS. 3 and 4, the piston 2 has a first extension side,
The pressure side damping valves 4 and 5 and the rotary valve 8 constituting the variable orifice 13 are arranged in parallel as in the conventional case.

However, in this embodiment, the expansion side overwhelming damping valves 4 and 5 are both flexible type valves 4A and 5A, which open and close ports 4B and 5B, respectively. Note that the seat portion of the outer port 5B is raised in an annular shape around the port opening, so that the inner port 4B is in communication with the oil chamber A even if there is a flap valve 5A.

(The interior of the piston nut 15 fitted into the piston 2 includes a switching valve 16, a second expansion side damping valve 1, and a compression side damping valve 1.
7.18 will be placed.

The switching valve 16 has a first damping valve 4.5 and a second damping valve 1.
7.18 is selectively short-circuited with the oil chamber B by opening and closing the bypass port 20,
It is attached to an operating rod 7 that passes through the piston rod 6.

Note that the oil passage 19 also communicates with a passage 1° of the variable orifice 13.

The bypass port 20 is connected to the cylindrical portion 22 of the piston nut 15.
The switching valve 1 is provided on the inner circumference of the cylindrical portion 22.
The valve portions 23 of No. 6 are in sliding contact.

As shown in FIG. 4, the switching valve 16 has two valve parts 23 formed by symmetrically cutting out a part of a cylinder body, and a valve part 2.
3, and a slit leg 26 (formed by cutting off both sides) of a hollow shaft 27 that is engaged with the tip of the operating rod 7 is inserted into a long hole 25 provided at the center of the support arm 24. The switching valve 16 is configured to rotate as the rod 7 rotates.

The rotary valve 8 is formed in the middle of the hollow shaft 27,
As shown in Fig. 5, the opening/closing relationship between the rotary valve 8 and the switching valve 16 is as follows: when in neutral mode, both are open; when rotating clockwise, the rotary valve 8 closes and the switching valve 16 opens; when rotating counterclockwise, both open and close. It is set to close.

Like the first damping valve 4.5, the second expansion-side overwhelming damping valve 17.18 is composed of leaf valves 17Δ and 18A that open and close ports 17B and 18B, and each of the damping valves 17. The inflow ports of the 18 ports 17B and 18B are formed so that oil inflow into each other is not obstructed by the leaf valves 18Δ and 17A.

Next, the effect will be explained.

At the neutral position of the operating rod 7, the rotary valve 8 opens the variable orifice 13, the switching valve 16 opens the bypass port 20, and the oil passage 19 communicates with the oil chamber B (see FIG. 5A).

Therefore, during pressure-side operation, the hydraulic oil in the oil chamber B passes through the oil passage 19 from the bypass port 20, which has much less resistance than the second pressure-side damping valve 18, and expands the first pressure-side damping valve 5. It flows into the chamber A, and a part of it passes through the variable orifice 13 and also flows into the oil chamber A. Similarly, during the rebound side operation, the hydraulic oil in the oil chamber A flows through the first rebound side damping valve 4 and the variable orifice 13 in a light manner. The oil flows into the passage 19 and further flows out from the bypass port 20 to the oil chamber B.

Therefore, the second capital reduction valve 17.18 does not work at all, and the damping force is generated mainly by the first expansion and compression damping valves 4.5 and the variable orifice 13, resulting in a relatively soft (normal) damping characteristic. can get.

Next, turn the operating rod 7 clockwise to close the rotary valve 8 while leaving the switching valve 16 open (see Figure 5B).
The hydraulic oil now flows only through the first damping valve 4.5.

Therefore, compared to the above-mentioned neutral state, the variable orifice 13
Since the entire flow amount flows to the first extension side, the overwhelming damping valve 4.5, the damping force increases relatively by that amount.

For example, in driving conditions where handling stability is important, such as when driving at a high speed, the damping force is increased especially in the low piston speed range to obtain a slightly stiffer damping characteristic.

On the other hand, when the switching valve 16 is closed together with the rotary valve 8 by counterclockwise rotation of the operating rod 7, the first damping valve 4.5
Communication between the dark oil passage 19 and the second damping valve 17, 18 and the oil chamber B is cut off (FIG. 5C).

As a result, during overwhelming operation, for example, the hydraulic oil in the oil chamber B first pushes the second pressure-side damping valve 18 wide and flows into the oil passage 19,
Furthermore, the first overwhelming damping valve 5 is pushed wider and the oil flows into the oil chamber A. In this way, by passing through the two damping valves 18, it encounters a large resistance and generates a high damping force.

At this time, by changing the set value of the damping force of the second overwhelming damping valve 18, the damping characteristics can be greatly changed during adjustment.

During the rebound-side operation, the hydraulic oil in the oil chamber A passes through the first rebound-side damping valve 4 and the second rebound-side damping valve 17, which are in series with each other, thereby obtaining a large damping force in the same manner as above. Yes, this prevents the shock absorber from bottoming out or collapsing when driving on rough roads, for example.

Figure 6 shows the relationship between these damping characteristics.In this way, the first and second damping valves, which have a large flow rate control width, are selectively connected in series, so unlike the conventional variable orifice, the piston When adjusting the damping force from low speed range to high speed range, it can be set very large.

FIG. 7 shows another embodiment of the present invention.
The difference from the diagram is that the first overwhelming damping valve 5' is a non-return valve, and the annular valve 30 is replaced by a cone spring 31.
The structure is such that the valve is biased in the valve closing direction.

Therefore, in this case, since the first compression damping valve 5' is easy to open, the damping force on the compression side when the switching valve 16 is opened is lower than that on the rebound side.

As described above, the present invention provides a soft damping characteristic due to the parallel circuit of the first damping valve and the variable orifice, a slightly hard damping characteristic due only to the first damping valve, and a soft damping characteristic due to the parallel circuit of the first damping valve and the variable orifice. Very hard damping characteristics can be freely selected through series connection, and the damping force adjustment from low piston speed range to high speed range can be greatly changed depending on the usage conditions of the vehicle, improving the ride comfort and handling of the vehicle. This has the effect of satisfying both conditions.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional device, and FIG. 12 is a diagram showing its damping characteristics. Fig. 3 is a sectional view of main parts showing an embodiment of the present invention, Fig. 4 is a sectional view taken along line tr of Fig. 3 showing a switching valve, and Figs. 5A and B.
, C are explanatory diagrams showing the opening/closing relationship of the rotary valve and the switching valve, FIG. 6 is a damping characteristic diagram of the present invention, and FIG. 7 is a sectional view of a main part of another embodiment. DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Piston, 4... First expansion side damping valve, 5... First compression side damping valve, 6... Piston rod, 7... Operating rod, 8 ... rotary valve, 15 ... piston nut, 16 ... switching valve, 17 ... second expansion side damping valve, 18 ... second pressure side damping valve, 19 ... oil path, 20...Bypassport. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 7

Claims (1)

[Claims] 1. The piston is connected to the cylinder, the combined piston is housed to form upper and lower oil chambers, and the piston is provided with first expansion side and compression side damping valves in parallel. , a variable orifice that short-circuits the upper and lower oil chambers is provided, and the piston is further provided with the above-mentioned first
A second expansion and compression side damping valve is arranged in series with the expansion and compression side damping valves, and a switching valve is provided to selectively short-circuit the oil passage between the first and second damping valves to the oil chamber. The damping force adjustable hydraulic slack IL 2 is characterized in that the switching valve is rotatably driven from the outside via an operating rod penetrating the piston rod in conjunction with the variable orifice. The damping force adjustable hydraulic 11I device described in Range No. 1.