JPS59117933A - Hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To make each damping force at both extension and pressure sides adjustable at the same time in a separate manner, by rotating a rotary valve, while interconnecting or intercepting each of oil holes installed in a hollow piston rod and an oil passage set up in the rotary valve. CONSTITUTION:In the case where a hollow piston rod 2 is shifted in its extension direction, first a rotary valve 9 is rotated, then when each of oil holes 10 and 11 is interconnected to other oil holes 6 and 7, oil in an oil chamber 21 flows into an oil chamber 22 after passing through a damping valve 16 at the extension side and, what is more, flows into the oil chamber 22 via these oil holes 6 and 10 and a suction check valve 20 at the extension side, while the oil running past these oil holes 6 and 10 also flows into an oil reservoir chamber 23. In this case, the suction check valve 20 at the expansion side is opened to the full extent whereby damping force can be lowered down. At the pressure side, with oil passed through both sides of each of these oil holes 6, 10 and 7, 11, the damping force is made to be dropped to proper extent.

Description

[Detailed description of the invention] The present invention relates to a hydraulic shock absorber capable of adjusting damping force.

Hydraulic shock absorbers are installed between the vehicle body and the axle in order to absorb the natural vibrations generated by shocks received by the suspension springs while the vehicle is running, quickly dampen the vibrations, and improve riding comfort.

In addition, in order to damp vibrations as mentioned above, a damping valve is installed on the piston that divides the inside of the cylinder, which is sealed at both ends, into an oil chamber, and the piston rod to which this piston is attached is fitted with a damping valve. At the time of entry and exit, oil is caused to flow from one side of the oil chamber to the other through the damping valve while generating a predetermined flow resistance, thereby generating a desired damping force.

Furthermore, due to the difference in operating type, such hydraulic shock absorbers include single-effect damping valves that generate damping force only when the piston rod moves in or out, and dual-effect damping valves that generate damping force during both movements. There are types equipped with valves, and hydraulic shock absorbers with dual-acting damping valves have come to be widely used to improve running performance and stability when the vehicle turns at high speeds.

By the way, in recent years, hydraulic shock absorbers have been provided that allow occupants to arbitrarily adjust the damping force according to the load applied to the vehicle body. If the compression stroke is to be used, it is necessary to separately attach damping force variable means, such as externally operated rotary valves, to both the rebound damping valve and the compression damping valve.

As a result, the structure becomes complicated, the damping force adjustment operation becomes troublesome, and when the operation is performed while driving the vehicle, there arises a problem that the steering stability deteriorates.

Although this invention solves such conventional problems,
The purpose of this invention is to rotate two rotary valves by means of the external movement of the control rod, thereby making it possible to adjust the damping force on the extension side and the mounting force on the compression side separately and simultaneously.

Therefore, the present invention provides a cylinder whose both ends are sealed, a hollow piston rod which is inserted into and out of one sealed end of the cylinder and has a gas chamber and an oil reservoir formed therein, and the hollow piston. It has an oil hole in rice 1 and a second oil hole drilled at three places in the axial direction of the rod end, and an oil hole in fang 3 and an oil hole in fang 4 that communicate with these oil holes, and A cylindrical rotary valve with open ends that rotatably slides on the inner periphery of the end of the hollow piston rod, a control rod that operates the rotary valve from the outside of the hollow piston rod, and a control rod that closes the open lower end of the mouth valve. , a piston valve provided on the end side of the hollow rod, and having a compression side damping valve and an extension side suction check valve, and a hollow piston between the oil hole of Section 2-A-1 and the oil hole of fang 2. The piston is fitted onto the outer periphery of the rod and slidably contacts the inner circumferential surface of the cylinder, and has a damping valve on the extension side and a suction check valve on the compression side.

An embodiment of the present invention will be specifically described below with reference to the drawings.

Figure 1 shows an example of this in detail.
1) is a cylinder with both ends sealed, and a hollow piston rod (2) is inserted into the sealed end of this cylinder.

This hollow piston rod (2) is sealed with a sealing material (31K) at its sealed end, and is supported by a bearing (4) so as to be freely slidable in the axial direction. The upper end is sealed with a sealing material (5), and the lower end is opened downward. On the outer periphery of the lower end of this hollow piston rod (2), there are oil holes f6) at three locations in the axial direction. and '4-2 oil holes (7) are drilled.

A control rod (8) is inserted into the hollow piston rod (2) and supported in a liquid-tight manner by the sealing material (5), and is driven manually or by a motor as required. A cylindrical rotary valve (9) with both ends open is rotatably inscribed in the lower end of the control rod (8). ) and rice 4 oil hole ([1
1 is the oil hole (6) of the above mail 1 and the oil hole (7) of A-2.
), so that they can communicate with each other. +ta is an open oil hole provided at the upper end of the rotary valve (9).

(I3) is the +1 oil hole (6) and the fang 2 oil hole (7).
), this piston is inserted into the outer periphery of the hollow pin (2) between the hollow piston mouth (2).
2) It is fixed by a piston nut (1411) screwed into the outer periphery of the end. (15) is a communication hole drilled in the piston nut (141) in order to always communicate with the oil hole (7). In addition, the above piston/12)K has a rebound side chastity reduction valve (16) and a compression side suction check valve (
In is provided.

(18) is provided at the end of the piston nut (14),
It is a piston valve that closes the lower open end of the hollow piston rod 121: t6 and the rotary valve (9), and this piston valve (18) is provided with a compression side damping valve (field and offshore side suction check valve 1211). ra't
I'm here.

The piston (I3) has an oil chamber (21) inside the cylinder (1).
) and an oil chamber t221K, and the inside of the hollow piston nut (2) is divided into an oil reservoir chamber (231) and an air chamber (241) serving as a two-part gas chamber, and an oil chamber (241) at the interface between oil and air. The air chamber (24) is compressed and expanded to compensate for the volume of the hollow piston rod (2) entering the cylinder 11), and can be made into a gas chamber if necessary. can.

Next, the operation of the real sister example having such a configuration will be explained.

(a) When the hollow piston rod (2) moves in the direction of extension relative to the cylinder (1).

First, λ-3 and ME-4 (7) of the rotary valve (9).
)? +4y hole (+o+nn), hollow piston rod f21671-1 and fang 2 oil hole f61 (71
In the state where each VC is not connected, piste 1
Due to the upward movement of /(+31), the oil pressure in the oil chamber 121) increases, and the oil pressure in the oil chamber (221) tends to decrease to negative pressure. Therefore, the oil pressure balance between these two oil chambers 121) +22) is maintained. As a result, the oil in the oil chamber (21) flows into the oil chamber (22) through only the rebound damping valve 116). This oil flow”1. is throttled in the damping valve +te+K, creating a high flow resistance and a large vibration damping force.

On the other hand, in order to lower the damping force, the control rod (8) is operated to rotate the rotary valve]9), thereby opening each of the oil holes 110) to the oil hole (
61 (7), the oil in the oil chamber (21) passes through the expansion damping valve (16) and flows into the oil chamber 122.
1 In addition to the VTC inflow, oil hole (6) on fang l, oil hole 110 on tsu 3) and extension side suction check valve +20)
The oil that flows up to the oil chamber (22) through the oil hole +6+r+n+ and further passes through the oil hole +6+r+n+ flows into the rotary valve (
9) It also flows into the oil sump chamber (23) in the hollow bisto cylinder (2) through the open oil hole (12) provided in the upper part.

Note that the air in the air chamber (24) is compressed by the oil flowing into the oil reservoir chamber (23).

By the way, in this case, the other oil hole (7) (marked is also in communication state, but during the extension stroke, the above-mentioned extension side suction check valve + 2fl) opens immediately and widely, so that the inside of the hollow of the rotary valve (9) The oil introduced into
The oil chamber 1221 V is inserted through this extension side suction check valve 120) without passing through the oil hole (7)
C will flow in. As a result of (B), the oil in the oil chamber (23+) flows to the oil chamber (221) via the expansion side suction check valve other than the expansion side damping valve (6), so the damping force can be reduced.

Therefore, the oil in the oil chamber 1221 is removed from the piston valve (18).
Pass through the compression side damping valve decoration of the rotary valve C9)
The oil flows into the oil sump chamber (23) from inside the hollow. Therefore, a predetermined vibration damping force is generated by the compression side damping valve Q(]). On the other hand, when the piston 03) acts on the pressure side, the pressure side suction check valve 0η provided on the piston 6 immediately opens.
) to the original oil quickly, and immediately these two oil chambers f2
11 +22) pressure will be balanced. For this reason, the vibration damping force on the compression side is better if the vibration damping force on the extension side is larger.

1. On the other hand, in order to reduce the vibration damping force on the compression side,
By operating the control rod (8), 7 rotates the rotary valve (9), which causes oil hole 1
0) When the [marks are connected to the oil holes f6) and f7), the oil in the oil chamber (22) will flow through the pressure side damping valve (19).
) In addition to flowing into the oil reservoir chamber (23) through the pressure side suction check valve (17), the oil flows into the oil chamber (2()) and goes around the outer periphery of the hollow piston: Nororad 12. Pass through the oil hole f611101 above and enter the oil sump chamber (
23) Insert addition 4 inside. Furthermore, the oil in the oil chamber (221) passes through the oil hole f71fl to the rotary valve (9).
It flows into the oil reservoir chamber (231) through the hollow and the oil hole (12). Therefore, the damping force decreases by the amount that the oil passes through the oil hole (61 (101) and the oil hole (7) (marked). In addition, these oil holes 761!101 and oil hole f71
(The oil that has entered the oil reservoir chamber +231 through +11 compresses the air in the air chamber (24) and compensates for the amount of body that enters the cylinder (1) of the hollow piston rod (2). It works like this.

In other words, when reducing the damping force by communicating the oil holes (6) and (10) and communicating the oil holes (7+ and (11)), on the extension side, one of the oil holes (6) and t+0
By letting oil pass through 1, the damping force is reduced, and on the pressure side, the oil hole (6) and aO) and the oil hole (7)
By passing oil through both (11) and (11), the damping force is reduced. In this case, the oil hole r10) provided in the rotary valve 19)
By arbitrarily selecting the magnitude of the damping force (old), the magnitude of the damping force on the extension side and the compression side can be arbitrarily selected.

Figure 2 (α) (b) shows a cross-sectional view of the structure of a rotary valve 19) that changes only the damping force on the compression side without changing the damping force on the rebound side by rotating the rotary valve (9). It is something. In the same figure, (10α) (10b) and (11α) (11b) are oil holes located at two opposite locations on the upper and lower sides of the rotary valve (9).
) (1ob) has a larger opening diameter than the oil hole (11α) despite the same l/fi.

Such oil hole (10α) (to&)' (nα) (i
In the rotary valve (9) with li, by rotating it, the oil holes (10α) (11α) are connected to the oil holes 161 (71) of the hollow piston rod, respectively.
In the case where the oil holes (10h) (11b) are connected to the oil holes (61 (71K) respectively), during the pressure stroke,
The flow rate of oil flowing through the oil hole (7) via the oil hole (11α) (11h) is different. For this reason, the above rotary valve (9)
By rotating, the damping force on the rebound side does not change, but the damping force on the compression side can be changed.

Also, the above oil hole (10α) (10h) (11α) (]
, 1h) by arbitrarily selecting the thickness and number of
It is also possible to adjust the damping force only on the extension side or on both the extension and compression sides at the same time. In addition, in order to obtain the same effect, the hollow piston rod (2) 6 is provided with a plurality of oil holes with different opening diameters, and the rotary valve (9) K is provided with one oil hole at the top and bottom of the rotary valve (9). 9), each oil hole provided therein selectively communicates with each of the plurality of ft1+ holes of the hollow piston rod (2).
It is also possible to

As explained in detail above, according to the present invention, the rotary valve rotatably fitted in the hollow piston rod is rotated by external operation, and the oil hole provided in the hollow piston rod and the oil hole provided in the rotary valve are By communicating or disconnecting the passage, oil can flow in parallel to the damping valve between the oil chambers separated by the piston and between these chambers and the oil reservoir chamber in the hollow piston rod. By doing so, the vibration damping force can be adjusted arbitrarily according to the magnitude of the load on the vehicle, and even in models with dual-effect valves for damping force, it is possible to adjust the vibration damping force on both the rebound and compression sides. The advantage is that damping force adjustment can be carried out individually and simultaneously by only intermediate manipulation of the control rod.

[Brief explanation of the drawing]

Oh 1 Figure 1. Fig. 2 (α) is a longitudinal cross-sectional view showing an embodiment of a hydraulic shock absorber according to the present invention. Fig. 2 (α) is a sectional view taken along line A-A of Fig. 1 showing an embodiment of a rotary valve. Fig. 2 (h) is a longitudinal sectional view showing an embodiment of a hydraulic shock absorber according to the present invention. Similarly, it is a sectional view taken along the line B-B. (1)...Cylinder, (2)...Hollow piston rod, (61(7)...Oil hole i81...Control rod, (9)...Rotary valve, (10) Old 1
Fl, 21... Oil hole, (13)... Piston, (1
G)... Rebound side damping valve, (17)... Compression side suction check valve, cl &... Piston valve, (19
)...Compression side damping valve, +2 (li...Rebound side suction check valve, +211 +221...Oil chamber, (2
3)...Oil storage room, example...gas room.

Claims (1)

[Claims] +] l A cylinder sealed at both ends, a hollow piston rod inserted into and out of one sealed end of the cylinder and having a gas chamber and an oil reservoir chamber inside, and this hollow piston. It has an oil hole in the fang 1 and an oil hole in the tooth 2 that are bored in two places in the axial direction of the rod end, and an oil hole in the fang 3 and an oil hole in the rice 4 that communicate with each of these oil holes, respectively. and a cylindrical rotary valve with open ends that rotatably slides on the inner periphery of the end of the hollow piston rod, a control rod that rotates the rotary valve from outside the hollow piston rod, and a control rod that closes the open lower end of the rotary valve. and a piston valve provided on the end side of the hollow rod and having a compression side damping valve and an extension 1 suction check valve, and a piston valve on the outer periphery of the hollow piston rod between the oil hole 'A-1' and the second oil hole. A hydraulic shock absorber comprising: a piston attached to the cylinder, the piston being in sliding contact with the inner circumferential surface of the cylinder, and having an extension side damping valve and a compression side suction check valve. The hydraulic shock absorber according to claim 1, wherein a plurality of oil holes (+21+1) and oil holes (2) are provided in the hollow piston rod. f31+3. Claim 1, wherein a plurality of oil holes and a plurality of oil holes of fangs 4 are provided in the piston valve.
Hydraulic shock absorbers as described in Section. (4) The hydraulic shock absorber according to claim 1, wherein the control rod is driven by a motor.