JPH0434235A - Shock absorber - Google Patents

Abstract

PURPOSE:To generate damping force of linear characteristic with a different tendency in a piston speed so as to remove an influence of dispersion in manufacture by providing a hole, which guides fluid to the second valve unit, in the first valve unit and a hole, which allows outflow fluid from the periphery of the second valve unit to flow, in a stopper. CONSTITUTION:When a piston rod 26 is extended, a valve unit 18 is deflected by allowing fluid in a fluid chamber 12 to flow in a port 32 of a piston 16, and damping force C1 is generated by this deflection. When the valve unit 18 hits a stopper 24 to restrict the deflection at a piston speed V1, a valve unit 20 is deflected by allowing fluid to flow toward the valve unit 20 from a hole 38, and outflow fluid from the periphery is allowed to flow through a hole 42 of the stopper 24 to generate damping force C2 by deflection of the valve unit 20. When the valve unit 20 is not deflected by hitting the stopper 24 at a piston speed V2, a valve unit 22 is deflected by flowing fluid in the valve unit 22 from a hole 40, and outflow fluid from the periphery flows through a hole 44 of the stopper 24 to generate damping force C3 by deflection of the valve unit 22.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a shock absorber, and particularly to a shock absorber suitable for use as a shock absorber in a vehicle suspension system.

(Prior Art) A cylinder, a piston that partitions the inside of the cylinder into two liquid chambers and has two sets of ports that allow liquid to flow in opposite directions between the two liquid chambers, and a plurality of pistons having different outer diameters. A plurality of valve bodies made of leaf springs for opening and closing each of the two sets of ports, which are stacked one on top of the other in order from the one with the largest outer diameter, and the one with the largest outer diameter is in contact with the piston. There is a shock absorber equipped with a stopper that restrains the deflection of these valve bodies as a whole (Utility Model Application No. 58-13).
5538).

In this shock absorber, multiple valve bodies with different outer diameters are stacked one on top of the other. When the piston speed is slowest, the outer circumferential edge of the valve body with the largest outer diameter is deflected, and then when the piston speed is faster, As the temperature increases, not only the outer circumferential edge of the valve body but also almost the whole of the valve body and the valve body with the second largest outer diameter adjacent to this valve body are deflected, thereby increasing the damping force over a wide speed range. Based on the need that arises. In this case, since the plurality of valve bodies function integrally, their spring constant, ie, bending rigidity, is substantially determined as a whole, and the damping force characteristic is linear.

(Problem to be solved by the invention) The shock absorber of a vehicle suspension system generates a high damping force in the low speed range of the piston to ensure maneuverability, and a low damping force in the mid-speed range of the piston to ensure ride comfort. However, since the shock absorber has substantially one spring constant, damping forces with different characteristics as described above cannot be obtained.

Sometimes an orifice is provided in the piston, and the orifice generates a damping force in the low speed range of the piston, but in this case, the damping force varies greatly depending on the area of the orifice, so the damping force may vary due to manufacturing variations in the orifice. It varies depending on the shock absorber. Further, when an orifice is provided, the damping force generated is proportional to the square of the velocity of the liquid, so its characteristics are nonlinear.

Therefore, an object of the present invention is to provide a damping device that can generate a damping force with a linear characteristic that varies depending on the piston speed, and can eliminate the influence of manufacturing variations as much as possible.

(Means for Solving the Problems) A shock absorber according to the present invention includes a cylinder and two parts inside the cylinder.
a partition member that partitions into two liquid chambers and has two sets of ports that allow liquid to flow in opposite directions between the two liquid chambers; and a partition member that is made of at least two leaf springs having different outer diameters; The first valve body that opens and closes one of the ports and has the largest outer diameter, and then the second valve body that has the next largest outer diameter, and so on. comprising at least two valve bodies with the valve bodies in contact with the partition member, and a stopper that individually restrains the deflection of these valve bodies,
The first valve body has a hole that guides liquid to the second valve body, and the stopper has a hole that allows liquid flowing out from the outer periphery of the second valve body to flow.

(Operations and Effects) In the low speed range of the piston, the outer peripheral edge of the first valve body, which has the largest outer diameter, bends, and the resistance at this time generates a damping force. When the piston speed increases, almost the entire first valve body flexes and hits the stopper, and the first valve body does not flex any further. Thereafter, the second valve element begins to bend due to the pressure of the liquid flowing out from the hole of the first valve element towards the second valve element, generating a damping force. The liquid flowing out from the outer periphery of the second valve body flows through the hole in the stopper.

Because the first valve body has a hole that guides the liquid to the second valve body, and the stopper has a hole that allows the liquid flowing out from the outer periphery of the second valve body to flow. Even if the valve element 41 hits the stopper, the second valve element can be deflected by the hydraulic pressure depending on the piston speed. As a result, the characteristics of the damping force generated until the first valve body hits the stopper and its deflection is restrained, and the characteristics of the damping force generated when the second valve body deflects are both linear. However, due to the difference in bending rigidity caused by the difference in the outer diameter of the valve body, different tendencies will be exhibited.

The resistance of the liquid flowing through the orifice is proportional to the square of the liquid's velocity, but the resistance to deflecting the leaf spring is proportional to the liquid's velocity. Therefore, in the case of a small orifice with a small flow path, if manufacturing variations occur in the orifice, the velocity of the liquid changes immediately due to the variations, and the damping force varies in proportion to the square of the velocity. In contrast, in the case of a leaf spring valve body, the effective flow area is determined by the outer diameter of the valve body, so even if there is slight manufacturing variation in the outer diameter, which is sufficiently large compared to the orifice, the liquid flow There is no change in speed and the damping force remains essentially constant. In this manner, the present invention, which does not include an orifice, can eliminate the influence of manufacturing errors in the valve body.

By appropriately selecting the bending rigidity of the multiple valve bodies, it is possible to generate damping forces with different characteristics, such as a higher damping force in the low speed range of the piston and a lower damping force in the medium speed range of the piston. It is possible to obtain a damping force suitable for the purpose of use. Therefore, if the shock absorber according to the present invention is used as a shock absorber for a vehicle suspension system,
It is possible to eliminate situations such as poor damping at the beginning of rolling and deterioration of ride comfort during medium and high speed driving.

(Example) The shock absorber shown in FIG.
A member 16 that partitions the inside of the liquid chamber 12.14 into two liquid chambers 12.14, a valve body 18.20.22 made of a leaf spring, and a stopper 24.

In the illustrated embodiment, the partition member 16 is a piston and is connected to a piston rod 26 by a nut 28 . The piston 16 has two liquid chambers 12.14 hermetically separated by a seal 30 attached to its outer circumferential surface, and has two sets of ports 32.34. The port 32 connects the liquid chamber 12 to the liquid chamber 14 when the piston rod 26 is extended.
The port 34 is connected to the piston rod 26.
When contracting, liquid flows from the liquid chamber 14 toward the liquid chamber 12.

Multiple valve bodies with different outer diameters form a unit to open and close ports. In the illustrated embodiment, the unit is composed of three valve bodies, including valve body 18, valve body 20, and valve body 2.
No. 2 has the smaller outer diameter in this order. Layer multiple valve bodies in this way, starting with the one with the largest outer diameter,
The valve body 18 with the largest outer diameter is brought into contact with the piston 16. A unit of these valve bodies opens and closes the port 32. The other port 34 is opened and closed by a leaf spring valve body 36.

The valve body for opening and closing the port 34 may be a unit made of a plurality of valve bodies having different outer diameters stacked one on top of the other, as in the present invention, in addition to the valve body 36 commonly used in shock absorbers.

The two sets of ports 32 and 34 provided on the piston 16 are
As shown in FIG. 2, they are arranged alternately in the circumferential direction. The port 32 has a notch 33 at its upper end;
There is no such notch at the lower end. The notch 33 is
When the piston rod 26 is extended, the liquid in the liquid chamber 12 can easily flow into the port 32. On the other hand, the ports 34 are formed by surrounding two parallel ports with a land 35 at their upper ends.

As shown in FIG. 3a, the valve body 18 is annular, and its outer periphery P1 is large enough to cover the port 32 of the piston 16 (see FIG. 1). The valve body 18 has four arc-shaped holes 38 for guiding liquid to the valve body 20 at equal intervals in the circumferential direction. The relationship between each hole 38 and the hole 32 of the piston 16 is such that the inner hole surface 39a of the hole 38 coincides with the innermost hole surface of the hole 32, as shown by the imaginary line, and
The hole surface 39b on the outside of the hole 32 is set to substantially coincide with the pitch circle passing through the center of the hole 32.

As a result, the proportion of the area covered by the hole 38 of the projected area of the hole 32 onto the valve body 18 can be reduced to about 30 to 40%, so that the liquid flowing out from the hole 32 first bends the valve body 18 itself. I can do it.

The valve body 20 is annular, as shown in FIG.
(See Figure a). The valve body 20 has four arc-shaped holes 40 at equal intervals in the circumferential direction for guiding liquid to the valve body 22. The relationship between each hole 40 and the hole 38 of the valve body 18 is as shown in FIG.
The ratio of the area of the hole 40 to the area of the hole 40 is set to be about 30 to 40%. Thereby, the liquid flowing out from the hole 38 can first cause the valve body 20 to bend.

As shown in FIG. 3C, the valve body 22 is currently in use, and its outer circumference P3 is large enough to cover the hole 40 of the valve body 20 (
(See Figure 3).

The stopper 24 is for individually restraining the deflection of the valve body.
In the embodiment shown in FIG. 1, the deflection of the valve body 18 and the valve body 20 is restrained. As shown in FIG. 4, the stopper 24 is
When the valve body 18 hits the stopper 24 , the four holes 42 spaced at equal intervals in the circumferential direction for flowing the liquid flowing out from the outer periphery of the valve body 20 and the valve body 20 hit the stopper 24 . The valve body 22 has four holes 44 equally spaced in the circumferential direction for allowing liquid to flow out from the outer periphery of the valve body 22.

The three valve bodies 18, 20, 22 and the stopper 24 have holes provided in their centers that connect to the end 27 of the piston rod 26.
It is attached to the piston rod 26 below the piston 16 by a nut 28 inserted into and screwed into the end 27.

The shock absorber is used by storing oil or other liquid inside the cylinder 10. When the piston rod 26 extends,
Since the liquid pressure in the liquid chamber 12 is higher than the liquid pressure in the liquid chamber 14, the liquid in the liquid chamber 12 flows into the port 32 of the piston 16 as shown in FIG. 18 is deflected and flows as shown in B (Figure a). At this time, the damping force generated by the deflection of the valve body 18 is 01 in FIG.
becomes.

When the piston speed reaches V, the valve body 18 hits the stopper 24 and its deflection is restrained, and the liquid flows from the hole 38 of the valve body 18 toward the valve body 20.
Deflect the valve body 20. Then, the liquid flowing out from the outer periphery of the valve body 20 flows through the hole 42 of the stopper 24, as shown in B2 (FIG. 2b). At this time, the damping force generated by the deflection of the valve body 20 becomes 02 in FIG.

When the piston speed reaches v2, the valve body 20 hits the stopper 24 and no longer deflects. Then, the liquid flows from the hole 40 of the valve body 20 toward the valve body 22,
Deflect the valve body 22. Then, the liquid flowing out from the outer periphery of the valve body 22 flows through the hole 44 of the stopper 24 as shown in B3 (C in the same figure). At this time, the damping force generated by the deflection of the valve body 22 becomes C3 in FIG.

@6 The shock absorber shown in figure consists of cylinder 10 and cylinder 1.
a piston 16 that partitions the interior of the liquid chamber 0 into two liquid chambers 12 and 14;
It includes two valve bodies 58 and 60 that open and close the port 32 and a stopper 62. The basic structure of this shock absorber is the same as that described above.

The outer diameter of the valve body 58 is larger than the outer diameter of the valve body 60;
is arranged so that it contacts the piston 16. As shown in FIG. 7a, the valve body 58 is annular and has three holes 64 for guiding liquid to the valve body 60. On the other hand, the valve body 6
0 is annular as shown in FIG.

The stopper 62 has a hole 66 through which liquid flows out from the outer periphery of the valve body 60 when the valve body 58 abuts against the stopper 62 .

When the liquid pressure in the liquid chamber 12 becomes higher than the liquid pressure in the liquid chamber 14,
As shown in FIG. 8, the liquid in the liquid chamber 12 is as shown in A.
It flows into the port 32 of the piston 16, bends the valve body 58, and flows as indicated by B1 (a in the figure). At this time, the damping force generated by the deflection of the valve body 58 is Dl in FIG.
becomes.

When the piston speed reaches v3, the valve body 58 hits the stopper 62 and its deflection is restrained, and the liquid flows from the hole 64 of the valve body 58 toward the valve body 60.
Deflect the valve body 60. Then, the liquid flowing out from the outer periphery of the valve body 60 flows through the hole 66 of the stopper 62, as shown in B2 (FIG. 2b). At this time, the damping force generated by the deflection of the valve body 60 becomes B2 in FIG.

As shown qualitatively in FIGS. 9 and 10, the characteristics of the generated damping force are linear. The slope of this damping force characteristic can be changed by changing the bending rigidity of the valve body. Further, the number of bending points can be changed by increasing the number of valve bodies and providing corresponding stoppers. In this way, the present invention can increase the degree of freedom in selecting the damping force.

In the above embodiment, only the essential parts of the shock absorber have been described, but the rest of the structure of the shock absorber may be the same as that used in a known shock absorber. Moreover, although the partition member is shown as a piston, if the shock absorber is of a twin cylinder type, the present invention can also be implemented in connection with a partition member disposed at the bottom of the inner cylinder.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the main parts of the shock absorber according to the present invention, Fig. 2 is a plan view of the piston, Fig. 3 a, b, and c are plan views of the valve body, and Fig. 4 is a plan view of the stopper. , Fig. 5 a, b, and c are cross-sectional views showing the operation, Fig. 6 are cross-sectional views showing the main parts of another embodiment of the shock absorber, and Fig. 7 a, b are cross-sectional views of another embodiment of the valve body. A plan view, FIGS. 8a and 8b are sectional views showing the action of the shock absorber shown in FIG. 6, and FIGS. 9 and 10 are damping force characteristic diagrams. Niji Linda, 16: Piston, 18. 20, 58. 60: Valve body, 24.62: Stopper.

Claims (1)

[Claims] A cylinder, and a member that partitions the inside of the cylinder into two liquid chambers, which allows liquid to flow in opposite directions between the two liquid chambers.
a partition member having a pair of ports; a first valve body having the largest outer diameter, which is a valve body for opening and closing one of the two sets of ports, the valve body being made of at least two leaf springs having different outer diameters; A second valve body having a larger outer diameter is stacked one on top of the other in order from the one with the largest outer diameter, and the first valve body is placed over at least two valve bodies that are in contact with the partition member, and the deflection of these valve bodies is the first valve body has a hole for guiding liquid to the second valve body, and the stopper has a hole for letting liquid flow out from the outer periphery of the second valve body. It has a buffer device.