JPH0415182A - Damping force adjustment damper - 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 damping force adjustment damper that can independently control rebound and overwhelming damping forces.

(Conventional technology) A rotary valve is placed through the piston rod, and this rotary valve is controlled by an external rotary solenoid to freely control the generated damping force according to operating conditions, etc. There is something that has been made possible.

(Problem to be solved by the invention) However, in this case, it is not possible to adjust the damping force on the rebound side and the compression side independently, and since the rotary solenoid is placed at the upper end of the piston rod, it is difficult to install the damper. There were problems with the length and the mounting space for the damper.

SUMMARY OF THE INVENTION An object of the present invention is to provide a damping force adjustment damper that can independently control the damping force on the rebound side and the compression side and also shorten the overall length.

(Means for Solving the Problems) The present invention has two oil chambers defined inside a cylinder above and below a freely sliding piston, an oil reservoir chamber formed outside the cylinder, and a lower oil chamber to an upper oil chamber. There is a check valve installed on the piston that allows only the flow of hydraulic oil into the oil chamber, and a check valve installed at the bottom of the cylinder that allows only flow of hydraulic oil, and an extension installed in the passage that communicates the upper and lower oil chambers. It includes a side pilot damping valve and a pressure side pilot damping valve interposed in a passage communicating the lower oil chamber and the oil reservoir chamber.

(Function) When the piston operates in the extension side, a rebound damping force is generated according to the resistance that the contracted hydraulic oil from the upper oil chamber receives when passing through the # side pilot damping valve. At this time,
Hydraulic oil from the oil reservoir chamber flows into the expanding lower oil chamber via a check valve.

When the piston operates on the pressure side, the hydraulic oil from the contracting lower oil chamber flows into the expanding upper oil chamber through the check valve, while the hydraulic oil corresponding to the piston rod intrusion volume flows into the pressure side pilot damping valve. It flows out into the oil sump room through
A compression damping force is generated depending on the resistance at this time.

Generally, the required damping force is lower on the compression side than on the rebound side, so the compression pilot damping valve opens at a lower pressure, and therefore the rebound pilot damping valve remains closed during compression operation, resulting in The damping force on the rebound side can be controlled independently of each other.

Note that the set pressures of the expansion-side and compression-side pilot damping valves can be freely adjusted by pilot pressures supplied from the outside.

(Example) As shown in FIG. 1, a cylinder 2 is arranged coaxially with an outer shell 1, and a piston rod 4
A piston 3 coupled to is slidably disposed. Upper and lower oil chambers 5 and 6 are defined inside the cylinder 2 by the piston 3, while an oil reservoir chamber 7 partially filled with gas is formed between the cylinder 2 and the outer shell 1.

The piston 3 is provided with a check valve 9 that allows hydraulic oil to flow from the lower oil chamber 6 to the upper oil chamber 5, and the bottom of the cylinder 2 is provided with a check valve 9 that allows hydraulic oil to flow from the oil reservoir chamber 7 to the lower oil chamber 6. A check valve 10 is provided to allow the inflow of. In addition, 15
is an orifice provided in parallel with the check valve 10.

A long passage 11 is formed that connects the upper oil chamber 5 to the lower oil chamber 6 via the outer periphery of the cylinder 2, and a rebound pilot damping valve 12 is interposed in this passage 11, thereby reducing the rebound damping force. On the other hand, a passage 13 is provided that connects the lower oil chamber 6 and the oil reservoir chamber 7, and a pressure side pilot damping valve 14 is interposed in this passage 13, thereby generating a compression side damping force. ing.

These expansion side and compression side pilot damping valves 12 , 14 have the same structure and are arranged on the outside of the lower part of the outer shell 1 .

Here, to explain the structure of one expansion side pilot damping valve 12, the plunger 1 responds to the pressure of the hydraulic oil passage 11.
6, a spool valve 17 driven by this plunger 16, a spring 18 that biases the spool valve 17 in the valve closing direction, and a pressure chamber 19 that biases these as well, and is introduced into the pressure chamber 19. The relief pressure when the spool valve 17 opens changes depending on the pilot pressure, that is, as the pilot pressure increases, the relief pressure increases and the generated damping force increases.

Therefore, by controlling the pressure supplied to one pressure chamber defined by a diaphragm or the like, the damping force generated by the expansion-side pilot damping valve 12 can be increased or decreased.

As shown in FIG. 2, normally the set load (relief set pressure) of the rebound side pilot damping valve 12 is set 6 relatively larger than the set load of the compression side pilot damping valve 14, The generated damping force is increased to prevent deterioration of ride comfort.

Note that 21 is an accumulator that absorbs the high pressure in the upper oil chamber 5 when the pressure is higher than a set value.

The system is constructed as described above, and its operation will be explained next.

When the piston 3 moves upward during expansion-side operation, the hydraulic oil in the contracted upper oil chamber 5 flows from the passage 11 to the lower oil chamber 6 via the expansion-side pilot damping valve 12. A damping force corresponding to the resistance of the pilot damping valve 12 is generated.

Note that the hydraulic oil corresponding to the volume of the withdrawal of the piston rod 4 flows into the lower oil chamber 6 via the check valve 10.

This rebound damping force can be adjusted by the pilot pressure Pt introduced into the pressure chamber 19 of the rebound pilot damping valve 12, and the larger the pilot pressure is, the more the spool valve 1
The hydraulic oil pressure for opening valve 7, that is, the damping force increases.

Next, during pressure-side operation when the piston 3 moves downward, the hydraulic oil from the contracting lower oil chamber 6 flows into the expanding upper oil chamber 5 via the check valve 9, and the volume of the piston rod 4 penetrates into the expanding upper oil chamber 5. Corresponding hydraulic oil flows out from the passage 13 communicating with the lower oil chamber 6 to the oil reservoir chamber 7 via the pressure side pilot damping valve 14. At this time, the pressure side pilot damping valve 14
Compression damping force is generated depending on the resistance.

Then, the pilot pressure P of the pressure side pilot damping valve 14
By controlling c, the generated damping force can be adjusted as desired.

In addition, because some of the hydraulic oil in the lower oil chamber 6 flows to the oil reservoir chamber 7 via the orifice 11, and because the set pressure of the pilot damping valve 14 on the compression side is relatively higher than that on the expansion side. As shown in FIG. 2, the generated damping force characteristics are relatively lower on the compression side than on the rebound side.

In this way, the damping force generated on the expansion side and the compression side can be independently controlled, and optimal damping force characteristics corresponding to the requirements can be provided.

In addition, since the rebound and compression side pilot damping valves 12 and 14 are provided protruding from the lower side surface of the outer shell 1, there is no need to increase the length in the damper axial direction, and there are great advantages in terms of installation space. .

Next, FIG. 3 shows an example of stabilizing the running attitude of the vehicle by independently controlling the damping forces of the left and right dampers 30 and 31 on the expansion side and the compression side.

The pilot damping valves 12a12b, 14a, 14b of each damper 30.31 include air supply valves 31a to 31d and exhaust valve 3.
2a to B2b control the pilot pressure to be supplied. The operation of these intake valves and exhaust valves is controlled by a controller 33, into which a signal from a sensor 34 that detects the operating state is input, and the left and right dampers 30 are operated to suppress rolling and pitching, for example. .31 damping force is controlled.

In addition, 35 is an air pressure source, and the pilot pressure increases when the air supply valves 31a to 31d are opened, and decreases when the exhaust valves 32a to 32b are opened.

In addition, if only to prevent rolling, the left and right dampers 30 and 31 operate on the expansion side and the other on the compression side when rolling, so the pilot pressure passages on the left and right expansion side and compression side are communicated with each other, and these are connected. Control may be performed using two intake valves and two exhaust valves.

(Effects of the Invention) As described above, according to the present invention, the damping force on the rebound side and the compression side can be controlled to the optimum state independently of each other, and also,
Since the damping valve can be attached to the side, the overall length of the damper can be shortened.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is a damping force characteristic diagram, and FIG. 3 is a circuit explanatory diagram of an applied example. 1... Outer shell, 2... Cylinder, 3... Piston, 4... Piston rod, 5, 6... Oil chamber, 7
...Oil sump chamber, 9,10...Check valve, 11.13
...Passage, 12.14...Pilot damping valve. Diagram

Claims (1)

[Claims] 1. There are two oil chambers defined above and below the piston that can freely slide inside the cylinder, an oil reservoir chamber formed on the outside of the cylinder, and only allow hydraulic oil to flow from the lower oil chamber to the upper oil chamber. A check valve installed on the piston that allows hydraulic oil to flow from the oil reservoir chamber to the lower oil chamber; A damping force adjustment damper comprising an interposed expansion side pilot damping valve and a pressure side pilot damping valve interposed in a passage communicating between a lower oil chamber and an oil reservoir chamber.