JPS5831496B2 - Shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shock absorber that is capable of automatically changing its compression damping characteristics in accordance with the loaded weight of a vehicle.

Shock absorbers used in vehicles, including motorcycles and four-wheelers, but especially vehicles with large body load fluctuations such as light vans and trucks, have the characteristic that the damping force changes depending on the load loading situation. things are required.

For this reason, shock absorbers such as those shown in FIGS. 1 to 3 have been considered in the past.

To explain this, in the figure, 1 is an outer cylinder, 2 is an inner cylinder, 3 is a base valve, 4 is a piston, and 5 is a piston rod.The piston 4 connects the inside of the inner cylinder 2 to an upper chamber 6 and a lower chamber. Divide into 7 sections.

As shown in FIGS. 2 and 3, the piston 4 is
The port 8 is provided with a port 8 through which oil in the lower chamber 7 flows toward the upper chamber 6 during the contraction side stroke of the shock absorber.
A constant orifice 9 and a compression damping valve 10 are installed in the piston rod 5, and a passage 11 is provided in the piston rod 5 to allow oil in the upper chamber 6 to flow toward the lower chamber 7 during the expansion stroke. In addition, an extension side damping valve 12 having a cutout orifice (not shown) is provided in the middle of this passage 11.
is interposed.

The sleeve 14 installed in the lower part of the piston 4 hits the position detection spring 15 arranged in the lower part of the inner cylinder 2 because the piston 4 strokes toward the upper part of the inner cylinder 2 when the loaded weight of the vehicle is small. The lower end position shown in FIG. 2 is held by the elasticity of the spring 16 and the side road 17 is opened.
5, it is pushed up against the spring 16 and closes the above-mentioned side passage 17 while maintaining the upper end position as shown in FIG.

As a result, as is clear from FIG.
m / sec or less), the oil in the lower chamber γ is passed through the constant orifice 9 formed in the piston 4 and the constant orifice 19 formed by the groove 18 formed in the inner wall of the inner cylinder 2, and also in the region where the speed of the piston 4 is high ( 0.3 m/sec or more), the compression side damping valve 10 provided on the piston 4 is pushed open to allow oil to flow into the upper chamber 6, and at the same time oil corresponding to the volume of the piston rod 5 entering into the inner cylinder 2 is is pushed out from the lower chamber 7 through the base valve 3 provided at the lower end of the inner cylinder 2 to the chamber 20 (see Figure 1) between the outer and outer cylinders 2.1, and at this time, the constant orifices 9, 19 and the damping valve mainly on the compression side 10 and the base valve 3 to provide resistance to the flow of oil to generate a desired relatively low damping force, and conversely, in the rebound stroke of the shock absorber, the speed of the piston 4 is in a relatively low range (for example, 0.1 m / sec), the oil in the upper chamber 6 flows from the constant orifices 9, 19 to the lower chamber 7, and in the region where the speed of the piston 4 is high (for example, 0.3 m/sec or more), the piston rod 5 The expansion side damping valve 12 is pushed open from the passage 11 provided in the port 13 and the side passage 1 while resisting the elasticity of the spring 210.
The constant orifices 9, 19 and the damping valve 12 provide resistance to the flow of the oil, producing a desired damping force higher than that during the previous contraction stroke. let

On the other hand, when the loaded weight of the vehicle increases and the initial position of the piston 4 moves relatively downward, as shown in FIG.
At the same time, the piston 4 comes to a position where the position detection spring 15 does not exist, and the sleeve 14 is pushed up by the position detection spring 15 to close the above-mentioned side passage 17.

As a result, the constant orifice in the compression side and expansion side strokes of the shock absorber is
Since the constant orifice 9 provided in Since the oil flows into the lower chamber 7 through only the port 13 without passing through the side passage 17, the port area on the back side of the damping valve 12 is reduced at this time, and the damping force characteristics generated in the extension stroke are relatively high. It will be done.

In this way, the damping characteristics can be changed relative to when the car is empty and when the car is loaded, but unlike the conventional system mentioned above, in the contraction side stroke when the car is empty and when the car is loaded,
In the case where the desired compression side damping characteristic is obtained by simply changing the area of the constant orifice, for example, the required damping characteristic C when the car is loaded and the required damping characteristic d when the car is empty, as shown by the solid line in Fig. is given, the set load at the beginning of opening of the base valve 3 and the compression side damping valve 10 is determined according to the required damping characteristic d when the vehicle is empty, and the constant orifice 9,190 area and the bow of the damping valve 100 passage are determined. 180 area and try to obtain the required damping characteristic C at that time, base valve 3 and damping valve 1
Since the pressure itself at the beginning of the zero opening does not change, even if there is a change due to the constant orifice 9, the damping characteristic when the vehicle is loaded will only be the characteristic shown by the dotted line C'.

Of course, if the set loads at which the base valve 3 and the damping valve 10 begin to open are set in accordance with the required damping characteristic C when the vehicle is loaded, the damping characteristic when the vehicle is empty will be as shown by the two-dot chain line d'. This means that the required attenuation characteristic d is not met.

The present invention was proposed in order to solve this problem, and provides a shock absorber in which the damping characteristics and characteristic widths on the compression side can be freely set when the vehicle is empty and when the vehicle is loaded. be.

Hereinafter, embodiments of the present invention will be described based on FIGS. 5 and 6 of the accompanying drawings. In the present invention, a port 22 is formed in the flange portion 14a of the sleeve 14, and
When the vehicle is empty, as shown in FIG. 5, the upper chamber 6 and the lower chamber 7 are connected to the annular gap 23 between the inner wall of the inner cylinder 2 and the outer periphery of the flange portion 14a and the port 22 formed in the 7-runway portion 14a. In addition, the constant orifice 19, the port 8 of the piston 4, and the constant orifice 9 communicate with each other via the compression damping valve 10, and when loading the vehicle, the sleeve 14 is connected to the position detection spring 15 as shown in FIG. When the sleeve 14 is pushed up, the upper surface of the flange portion 14a of the sleeve 14 is pressed against the lower surface of the piston 4, and the upper chamber 6 and the lower chamber 7 are connected only through the port 22 formed in the flange portion 14a to the port 8 and the piston 4. The constant orifice 9 and the compression damping valve 10 communicate with each other.

In addition, in this embodiment, a second extension damping valve 24 is disposed on the opening surface of the port 13 on the lower chamber γ side and opens and closes this port 13. The valve 24 reset load is set to satisfy the required characteristics on the expansion side in relation to the first expansion side damping valve 120 set load.

In this case, the second damping valve 24 in this embodiment is a leaf valve 24a fixed with a nut 26 via a washer 25.
The damping valve 240 set load can be adjusted by changing the initial deflection δ of the leaf valve 24a.

Note that the other components have the same configuration as the conventional ones shown in FIGS. 1 to 3 mentioned above.
Here, the same reference numerals are given and the explanation thereof will be omitted.

As a result, when the loaded weight is light, that is, when the vehicle is empty, the sleeve 14 is in the state shown in FIG. Oil flows from the annular gap 23 between the port 22 formed in the flange portion 14a and the inner wall of the inner cylinder 2 through the constant orifices 9 and 19 to the upper chamber 6, and an amount of oil corresponding to the entering volume of the piston rod 5 flows. passes from the lower chamber 7 through the base valve 3 to the inner and outer cylinders 2゜1.
However, during the contraction side stroke in the region where the speed of the piston 4 is high, oil in the lower chamber γ flows into the piston 4 at the same time.
from the port 8 of the retraction side damping valve 10 to the upper chamber 6, and therefore this la constant orifice 9
, 19, base valve 3, and damping valve 100 set load in accordance with the required damping characteristic d during the contraction side stroke when the vehicle is empty as shown in Fig. 4. can demonstrate its characteristics.

On the other hand, when the loading weight increases and the sleeve 14 is pushed up as shown in FIG. Therefore, during the contraction side stroke when the speed of the piston 4 is slow, the oil in the lower chamber 7 flows only from the port 22 formed in the flange portion 14a to the upper chamber 6 through the constant orifice 9, which has a smaller area than the port 22, and therefore, Like the conventional one, damping force is generated by the constant orifice 9 and the base valve 3, but during the contraction side stroke in the region where the speed of the piston 4 is high, oil in the lower chamber γ flows from the photo 22 to the damping valve. 10 is pushed open and flows into the upper chamber 6, the oil passage area becomes smaller due to this port 22 and the port resistance increases compared to the case when the car is empty. Therefore, the damping characteristics at that time are different from the base. It is determined by the so-called back throttle, which takes into account the resistance of the port 22 in addition to the valve 3 and the damping valve 10. Therefore, the area of the port 220 should be designed in accordance with the required damping characteristic C when loading vehicles as shown in Fig. 4. As a result, a relatively high damping characteristic meeting the required characteristic C can be obtained.

Of course, these damping characteristics during the contraction side stroke can be freely set by appropriately selecting the area of the constant orifice 9, 190, the reset load of the valve 3 and the damping valve 10, and the area of the hose 220.

Although not directly related to the gist of the present invention, during the rebound stroke, in the empty state shown in FIG.
side passage 1 through the cut-out orifice of damping valve 12 that does not open, or from passage 11 while pushing open first extension damping valve 12.
1 to the lower chamber 7, the area of the constant orifices 9, 19 and the notched orifice (not shown) and the set load of the damping valve 120 are calculated as follows: By setting them together, it is possible to exhibit a damping characteristic that meets this required damping characteristic.

Further, during loading as shown in FIG. 6, the sleeve 14 moves upward and the side passage 17 is closed, whereby the oil in the upper chamber 6 passes through the constant orifice 9 or the passage 11 also flows into the first passage. and second rebound damping valve 12.24
is pushed open and flows into the lower chamber γ, so the damping force generated at this time is mainly determined by the first and second damping valves 12 and 24. Therefore, the constant orifice 9 and the cutout orifice of the damping valve 12 (not shown) and the set loads of the first and second damping valves 12, 24 are set in accordance with the required damping characteristic a during the extension stroke when loading the vehicle as shown in FIG. , it becomes possible to obtain a damping characteristic that meets the required characteristic a.

As described above, according to the present invention, the port area, which is the back throttle of the compression side damping valve, is automatically changed depending on when the car is empty and when the car is loaded. It is possible to provide damping characteristics according to the respective requirements both during loading and unloading.

[Brief explanation of drawings]

Figure 1 is a schematic in-side view of the shock pumper, Figure 2 is an enlarged sectional view of the piston part of the conventional device when the vehicle is empty, and Figure 3 is an enlarged view of the piston part when the vehicle is loaded. 4 is a graph showing the damping characteristics, FIG. 5 is a sectional view showing the piston portion when the vehicle is empty, and FIG. 6 is a sectional view showing the piston portion when the vehicle is loaded. It is a diagram. 1... Outer cylinder, 2... Inner cylinder, 3...
...Base valve, 4...Piston, 5...
...-Piston rod, 6... Upper chamber, 7...
...Lower chamber, 8...Port, 9...
・Constant orifice, 10... damping valve,
14...Three 7.14a...Flange part, 15...Position detection spring, 19...
... Constant orifice, 20 ... Chamber, 22 ... Port, 23 ... Annular gap.

Claims (1)

[Claims] 1 A passage is formed in the piston that communicates the upper chamber and the lower chamber, and a contraction side damping valve that allows flow in only one direction is interposed in this passage, and the passage inlet side of this damping valve is connected to the opposite side of the piston. A shock absorber is provided with a sleeve that opens and closes via a position detection spring as the target position changes, and has a port that communicates with the passage when the sleeve is closed.