JPS6313933A - Valve mechanism of shock absorber - Google Patents

Abstract

PURPOSE:To increase the damping force within a low-speed range by providing, in addition to the main valve that opens an oil passage when a piston speed is in the medium-and-high-speed range, a sub valve that opens an oil passage when a piston speed is in the low-speed range at a speed higher than a fixed speed within said low-speed range. CONSTITUTION:When a piston 8 slides up and down and attains, within its low-speed range, to a speed higher than a fixed value, the pressure within a groove 17e, which is interconnected by means of a slit 18a with an oil chamber S1, increases, and then, the bore diameter parts of a slit valve 18 and a back-up valve 19 are warped downwards so that a passage 20 is opened here, and the hydraulic oil in the oil chamber S1 flows through the passage 20 and an oil hole 8b provided on the piston 8 into an oil chamber S2. Because the passage 20 is additionally opened, a damping force that rises rapidly is generated there, and subsequently, as the piston 8 increases its speed within the low-speed range, the damping force is also raised. Hereby, without varying the damping force characteristics in the medium-and-high-speed range, the damping force in the low-speed range can be increased.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is used for automobiles, motorcycles, etc.! a Regarding the valve structure of street appliances.

(Prior art) When the stroke speed of the piston is slow (for example, 0.1 m/s or less), shock absorbers used in automobiles, etc. lower the damping force to improve riding comfort, and reduce the stroke speed of the piston. When the speed is medium or high, characteristics such as high damping force and improved maneuverability are required, and for this reason, the 19th
As shown in the figure, a valve structure called the Sachs type is known.

To explain this Sachs type valve structure according to FIG.
), and a spring (108), a valve seat (107), a plate valve (1013), etc., and a valve seat are installed in this valve from the top in the drawing, and the piston speed (in the drawing, upward movement speed) is installed. When the speed is slow (for example, 0.1*/s or less), the plate valve (10B) hardly bends, and the plate valve (10B) and valve sea) (107
) remains in contact with the oil chamber (Sl), and the hydraulic oil in the oil chamber (Sl) flows between the legs of the valve guide (104) as shown by the arrow, through the oil hole formed in the slit (105a) and the piston (103). (103a) into the oil chamber (S2), and the damping force at this time is generated depending on the slit (105a). Also, when the piston speed becomes medium or high, the oil chamber (Sθ internal pressure increases and the plate valve (
10G) The inner diameter part is stacked downward and the valve seat) (1G7
), and in addition to the oil passage in the low speed range, an oil hole (107a) formed in the valve seat (10?) and an oil hole (107a) formed between the plate valve (toll) and the valve seat (107) are opened. Hydraulic oil flows into the oil chamber (S2) through the oil passage.

The damping force in the low speed range can be adjusted using the slit (105a).
) by changing the size of

(Problems to be Solved by the Invention) Recently, due to various improvements, the sliding friction at the sliding portion 1 of the shock absorber, such as the outer periphery of the piston and the inner periphery of the cylinder, has become extremely small. Conventionally, the above-mentioned sliding friction was large to some extent.

This sliding friction acts as resistance in the low speed range of the piston, and this provides appropriate ride comfort.However, as sliding friction has become extremely small recently, it actually causes damping in the low speed range. This results in a lack of power.

To solve this problem with the conventional valve structure, it is possible to reduce the area of the slit, but simply reducing the area of the slit will cause the piston speed to attenuate at very low speeds (for example, 0.01 m/s or less). There is a problem in that the lack of force is not improved, and the damping force increases rapidly in the range of piston speeds exceeding very low speeds, and does not smoothly continue with the damping force in the medium-high speed range.

(Means for Solving the Problems) In order to solve the above problems, the valve structure according to the present invention includes, in addition to the conventional main valve that opens the oil passage when the piston speed enters the medium/high speed range. When the piston speed is in a low speed range, a sub-valve is provided that opens the oil passage at a predetermined speed or higher within the low speed range.

(Function) If the piston is, for example, 0. It slides at a very low speed below O1/S, and when the internal pressure of the oil chamber on the compression side exceeds a predetermined value, the sub-valve opens the oil passage and generates an appropriate damping force.
Furthermore, another oil passage is opened by the main valve whose piston speed is in the medium-φ high-speed range, generating a damping force with excellent maneuverability.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view of the lower half of a shock absorber to which the valve structure according to the present invention is applied, and shows the outer cylinder (1) of the shock absorber.
) The lower end is closed with a cap (2), and this cap (2)
) to the bottom piece (3) installed on the inner cylinder (
4) The lower end is fixed.

A piston rod (5) is inserted into the inner cylinder (4) from above, a valve collar (7) is fitted onto the small diameter shaft portion (8) at the bottom of this piston rod (5), and a valve collar (7) is inserted into the inner cylinder (4) from above. A piston (8) slidingly contacts the inner circumferential surface of the inner cylinder (4) at the lower end of the shaft (6) as a positioning member.
is fixed with a nut (θ), and this piston (8) divides the inside of the inner cylinder (4) into an upper oil chamber (Sl) and a lower oil chamber (S2), and the lower oil chamber (S2) and the inner cylinder ( 4) and an oil reservoir chamber (S3) between the outer cylinder (1) and an oil hole (3a) formed in the bottom piece (3).
).

Further, a valve mechanism (lO) to which the valve structure according to the present invention is applied is installed on the upper part of the piston (8), and a bottom valve mechanism (30) to which the valve structure according to the invention is applied to the upper part of the potum bead (3). has been established.

As shown in the enlarged cross-sectional view of Fig. 2, the valve mechanism (10) includes a seven-rung portion (8a) protruding from the upper surface of the piston (8) and a support plate (11) attached to the stepped portion of the piston rod (5).
A valve guide (12) is provided between the main valve (13) and the sub valve (
14) are installed.

The main valve (13) is composed of a plurality of plate valves, and the outer periphery of this main valve (13) is connected to a valve guide (
12), and also the main valve (13).
The inner diameter of the bulb collar (7) is larger than that of the bulb collar (7), and a gap is formed between them. and the main valve (
The upper surface of the inner periphery of the valve seat (13) comes into contact with the lower surface of the inner periphery of the valve seat (15), and this valve seat (15) has an oil hole (15).
a) is formed and is urged downward by a spring (te).

On the other hand, the sub-valve (14) consists of a separator (17), a three-way valve (1B), and a backup valve (18).
) and Figure 3 (B), which is a sectional view taken along the line ■-■ of Figure 3 (A).
), the overall shape is approximately annular, and the inner diameter hole is provided with a protrusion (17a) that protrudes inward.
a) is brought into contact with the valve collar (7), a protrusion (17b) is formed on the outer circumference of the upper surface, the protrusion (1?b) supports the outer circumference of the lower surface of the main valve (13), and the lower surface of the main valve (13) is supported. A protrusion (17c) is formed on the outer peripheral part, and a downwardly extending thick part (17d) is formed on the inner diameter part, and this thick part (17d) and the protrusion (17c) are formed on the inner diameter part.
17c) to form a group (17e).

The lower end of the thick portion (17d) is located below the lower end of the protrusion (17c), and the inner peripheral portion of the upper surface of the slit valve (18) is in contact with the lower end of the thick portion (17d).

The slit valve (18) is shown in Fig. 4 (A) which is a bottom view and Fig. 4 CB which is a sectional view taken along line IV-■ in Fig. 4 (A)).
As shown in the figure, slits (18a)... are formed at equal intervals on the outer circumference of the annular plate valve, and a backup valve (18a) is stacked on the bottom surface of the slit valve (1B).
19) consists of a plate valve.

The operation of the valve mechanism (10) having the following construction will be explained based on FIGS. 2 and 5 to 8.

Here, Figure 7 is a graph showing the relationship between piston speed and damping force from low speed range to high speed range, and Figure 8 is an enlarged view of the low speed range part of Figure 7 (the area surrounded by dotted line A). In Figure 8, the horizontal axis (piston speed)
The damping force curve is more horizontal than the one in FIG. 7 because the distance between the two is larger than that in FIG. 7. Further, in FIGS. 7 and 8, the solid line shows the damping force curve of the conventional valve, and the two-dot line shows the damping force curve of the valve of the present invention.

First, immediately after the piston (8) starts sliding (moving upward in the figure), the internal pressure of the oil chamber (Sl) does not bend the inner diameter portions of the slit valve (18) and the backup valve (18), and the second As shown in the figure, the oil chamber (Sl) and the oil chamber (S2) do not communicate with each other.

After this, the speed of the piston (8) increases slightly (0.01
m/s or less), oil chamber (Sl) and three 7) (18a
) The pressure within the group (17e) that communicates with each other increases, and as shown in FIG. is opened, and the hydraulic oil in the oil chamber (Sl) flows through the flow path (20) and the oil hole (8b) formed in the piston (8).
) flows into the oil chamber (S2) through the oil chamber (S2) and opens the wave path (20), which generates a damping force that rises rapidly as shown in Figure 8, after which the piston (8) moves into the low speed range. By increasing the speed, the damping force also increases.

When the speed of the piston (8) reaches a predetermined speed exceeding 0.1 m/s, the hydraulic pressure acting on the upper surface of the main valve (13) causes the main valve (13
) The inner diameter portion bends downward to open a flow path (21) between the valve seat (15) and the valve seat (15). This point is the so-called blow-off point, and is indicated by point (a) in FIG.

When the flow path (21) is opened in this way, the hydraulic oil in the oil chamber (Sl) flows into the oil chamber (S2) through the flow path (21) in addition to the wave path (20), and from the blow-off point onwards. The damping force is the same as the conventional one, as shown in FIG.

Figures 9 and 10 show the separator (17) and slit valve (18) separately, and Figure 9 (A)
is a bottom view of the separator (17), and FIG. 9(B) is a sectional view taken along the line IX-IX in FIG. 9(A).
A groove (17f) is formed at an appropriate location on the protrusion (17c) formed on the outer periphery of the lower surface of ), and this groove (17f) allows the working oil in the oil chamber (S+) to flow into the group (17e). I'm trying to guide you. Therefore this separator (17)
If this is used, the slit valve (18) can be omitted.

Connect the backup valve (18) directly to the separator (17)
It can come into contact with the bottom surface.

In addition, Fig. 1O (A) shows a separate slit valve (1
8) bottom view, Fig. 1O (B) is x- of Fig. 1O (A)
This is an X-ray cross-sectional view, and this slit valve (18) has, in addition to a very low speed slit (18a) for introducing hydraulic oil into the group (17e) of the separator (17),
An extremely low speed slit 7) (18b) with a smaller surface than the slit (18a) is formed on the inner diameter portion.

By providing this slot 7) (18b), in the embodiment described above, as shown by the dotted line in FIG. However, by providing the slot 7) (18b), the flow path is slightly opened, and the damping force rises slightly as shown by the dashed line. The solid line in FIG. 11 is a damping force curve according to the conventional valve structure. In this way, the ride comfort is further improved by slowing down the rise of the damping force at extremely low speeds.

FIG. 12 is an enlarged sectional view of the bottom valve mechanism (3o), showing the bottom piece (3) and the inner cylinder (4).
A main valve (32) and a sub-valve (33) are arranged in a valve guide (31) held between the lower ends, and the upper surface of the main valve (32) is a spring (valve seat urged downward by 30) (35). The sub-valve (33) is supported by a separator (311i) having a group (38e) as described above, a slit valve (37) having a slit (37a) formed therein, and a backup valve (38).
), and its effect is that the damping force of the piston (8) in the low speed range is higher than that of the conventional one. However, piston (8)
The valve mechanism (10) installed in part J exhibits the damping force characteristics shown in Figures 7 and 8 during the shock absorber's extension stroke, but the bottom valve mechanism (3o) exhibits the damping force characteristics shown in Figures 7 and 8. During the compression stroke of the shock absorber, the damping force characteristics shown in FIGS. 7 and 8 are exhibited.

FIG. 13 is a sectional view of another embodiment in which the structure of the sub-valve is different, in which the sub-valve (40) has an annular separator (41).
, a shutoff valve (42), a group valve (43) and a backup valve (44).
) and the backup valve (44) between the group valve (
43) is held in between.

The group valve (43) is shown in FIG.
As shown in B), a plurality of slits (43a) are formed inward from the outer circumference, and groups (43b) connected to the slits (43a) are formed radially inward. Note that the other members are the same as those in the previous embodiment, and are therefore given the same numbers.

In the above, when the piston speed is extremely low, the first
As shown in Figure 3, the oil chamber (S+) and the oil chamber (S2) do not communicate, and when the piston speed becomes very low, the group (43
b) As shown in FIG. 15, the inner diameter part of the backup valve (40) is bent downward due to the pressure of the hydraulic oil introduced into the valve, and a flow path (20) is opened here, and at this point, as shown in FIG. As shown in Figure 8, a sudden damping force is generated.

When the piston speed increases further, the main valve (
13) is bent downward to open another flow path (blow-off point), and thereafter exhibits the same damping force characteristics as the conventional one.

In addition, the shutoff valve (42) and the backup valve (
42) are both composed of plate valves, and if the rigidity of the shut-off valve (42) is equal to or less than that of the backup valve (42), the shut-off valve (42) and group valve (43) will be closed at very low speeds. ) It is also possible to open a flow path (20) between them.

FIG. 16 is a cross-sectional view showing another embodiment in which the sub-valve structure is different, and the sub-valve (50) includes an annular separator (51), a shutoff valve (52), a slit valve (53), and a group valve ( 54) and a backup valve (55), a group valve (54) is sandwiched between the slit valve (53) and the backup valve (55), and a shutoff valve (5) is installed on the top surface of the slit valve (53).
2) is repeated.

Also, Fig. 17(A) is a bottom view of another example of the group valve (54), and Fig. 17(B) is Fig. 17(A) (7)XV
II - 54c).

Note that the outer ring (54a) and the inner link (54b) may have the same thickness.

In the above, if the piston speed is extremely low, the 16th
As shown in the figure, the oil chamber (Sθ) and the oil chamber (S2) do not communicate with each other, and when the piston speed becomes very low, the flow path (20) is opened and closed by the oil pressure in the group (54c) as shown in FIG. However, a damping force suddenly occurs as shown in FIGS. 7 and 8.

Figure 19 shows the group valve of the sub-valve (50) shown in Figure 16 between the inner ring (60) and the outer ring (8).
The inner ring (60) has a ring shape with a protrusion on the inner diameter as shown in Fig. 20 (A) and (B), and the outer ring (B1) is a simple ring. As shown in FIG. 22, when the piston speed becomes very low, the inner ring (60) is bent downward by hydraulic pressure to form an oil passage.

Although the illustrated example shows slit valves and group valves of various shapes, other embodiments (not shown) can be constructed by combining these.

(Effects of the Invention) As explained above, according to the present invention, a main valve and a sub-valve constitute a valve that generates a damping force, and in particular, the sub-valve opens a wave path at a predetermined value in a low piston speed range, and Since the flow path is not opened at speeds that do not reach the predetermined value, it is possible to increase the damping force in the low speed range without changing the damping force characteristics in the medium and high speed ranges. If applied to shock absorbers, the sliding friction of which has been reduced through various improvements.

This prevents insufficient damping force in the low speed range.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the lower half of a shock absorber to which the valve structure according to the present invention is applied, Fig. 2 is an enlarged sectional view of the same valve structure, Fig. 3 (A) is a bottom view of the separator, and Fig. i3 ( B) is the third
Fig. 4(A) is a bottom view of the slit valve, and Fig. 4(B) is the IV-m1 cross-sectional view of Fig. 4(A).
5 and 6 are cross-sectional views similar to FIG. 2 explaining the action of the valve structure. FIGS. 7 and 8 are graphs showing the relationship between piston speed and damping force. Diagram (A)
Figure 9CB) is a bottom view showing another example of the separator.
Figure (A) is a cross-sectional view taken along line IX-IX, Figure 1θ (A) is a bottom view showing another example of slit pulp, Figure 1θ (B) is a
FIG. 11 is a graph showing the relationship between piston speed and damping force at extremely low speeds, and FIG. 12 is a diagram showing the bottom valve structure to which the valve structure according to the present invention is applied. 13 is a sectional view of a valve structure according to another embodiment, and FIG. 14 (A) is a bottom view of a group valve.
Figure (B) is a bi-quadrature cross-sectional view of Figure 14 (A), Figure 15 is a cross-sectional view similar to Figure 13 showing the action of the valve, and Figure 16 is a cross-sectional view of Figure 14 (A).
The figure is a sectional view of a valve structure according to another embodiment, FIG.
) is the bottom view of the group valve, and Figure 17 (B) is the 17th
X17 II-XV IT line sectional view of figure (A), 1st
Figure 8 is a sectional view similar to Figure 16 showing the action of the valve, i
19 is a sectional view of a valve structure according to another embodiment, FIG. 20(A) is a plan view of the inner ring, and FIG. 20(B) is a sectional view of the
Figure (A) (7) XX-XX&a sectional view, Figure 21 (A)
21(B) is a plan view of the outer ring, and FIG. 21(B) is a plan view of the outer ring.
), FIG. 22 is a sectional view similar to FIG. 19 explaining the valve, and FIG. 23 is a sectional view of a conventional valve structure. In the drawing, (4) is the cylinder, (5) is the piston rod, (8) is the piston, (12), (31) are the valve guides, (13) is the main valve, (14), (33)
), (4,0). (50) is a sub valve, (15) is a valve seat, (1
? ). (3B), (41), (51) are separators, (18
), (37), (53) are slit valves, (19)
, (3111), (44), and (55) are backup valves, and (41) and (52) are shutoff valves. (A) (B) (A) (B) (A) (B) (A) (B) (A) (B) (A) (B) (A) (B) (A) (B) (A) (B) (A) (B) (A) (B) ! (m/S) Fig. 9 (A) (B) Fig. 10 (A) (B) Fig. 14 old) Fig. 17 (A) (B) Fig. 18

Claims (5)

[Claims] (1) A main valve and a sub-valve are arranged in the valve guide, and the sub-valve opens a flow path when the piston speed is above a predetermined speed within a low speed range, and the main bubble opens a flow path when the piston speed is above a predetermined speed within a medium/high speed range. A valve structure of a shock absorber characterized by opening a flow path. (2) The valve structure of a shock absorber according to claim 1, wherein a separator is interposed between the main valve and the sub-valve. (3) The shock absorber valve structure according to claim 1 or 2, wherein the sub-valve is formed by stacking a plate-shaped slit valve and a plate-shaped backup valve. (4) The sub-valve is formed by sandwiching a slit and a group valve forming a group connected to the slit between a plate-shaped shutoff valve and a plate-shaped backup valve. The valve structure of the shock absorber according to any of Item 2. (5) The sub-valve is formed by sandwiching both sides of a group valve between a plate-shaped slit valve and a plate-shaped backup valve, and further stacking a shutoff valve on the side of the slit valve opposite to the side that contacts the group valve. A valve structure for a shock absorber according to claim 1 or 2, characterized in that: