JPH0285531A - Hydraulic damper - Google Patents

Abstract

PURPOSE:To provide a hydraulic damper having a satisfactory deflecting characteristic and a stable damping force by superposing a plurality of resilient plates each having a plurality of cut-outs opened at its outer peripheral edge so as to be prevent their cut-outs from being communicated with each other, thereby forming a damper valve. CONSTITUTION:In a piston 5, there are disposed a first damper valve 11 for controlling the upward flow of oil from a first flow passage 9 so as to produce a contraction damping force during descent and a second damper valve 12 for controlling the downward flow of oil from a second flow passage 10 so as to produce an expansion damping force during ascent. In each of these damper valve 11, 12, a plurality of resilient plates 29 which are leaf springs each incorporating a plurality of cut-outs 28 opened at its outer peripheral edge are superposed with each other in such a condition that the cut-outs 28 in the resilient plates 29 are not communicated with each other, and cut-outs 28 in the resilient plates 29 adjacent to the corresponding valve seats 21, 22 are not communicated with the outlets of the flow passages. Thus, it is possible to obtain a satisfactory deflecting characteristic and a stable damping force.

Description

DETAILED DESCRIPTION OF THE INVENTION A0 Object of the Invention (1) Industrial Application Field The present invention relates to a hydraulic shock absorber that is attached to a suspension system of an automobile or the like and applies damping force to its operation, and particularly relates to a hydraulic shock absorber that is attached to a suspension system of an automobile or the like and applies damping force to its operation. a filled cylinder, a piston that is slidably fitted into the cylinder and has a flow passage that communicates the inside of the cylinder between an upper oil chamber and a lower oil chamber; The present invention relates to an improvement in a hydraulic shock absorber equipped with a shock absorber that bends so as to control the opening degree of a flow path according to the difference.

(2) Conventional technology Conventionally, in this type of hydraulic shock absorber, a buffer valve is constructed by superposing a plurality of seamless elastic plates (for example, in Japanese Patent Application Laid-Open No.
3-117169).

(3) Problems to be Solved by the Invention In a hydraulic shock absorber equipped with a buffer valve as described above, when the buffer valve is bent due to the pressure difference between the upper and lower oil chambers, each elastic plate is partially strained. As a result, the deflection characteristics of the buffer valve vary, and as a result, the generated damping force may not be stable.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydraulic shock absorber that has good deflection characteristics of a shock absorber valve and is capable of generating a stable damping force.

B3 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides a plurality of elastic plates each having a plurality of notches opening at the outer periphery, each of which communicates with each other. It is characterized in that the buffer valve is constructed by polymerizing to prevent it from occurring.

(2) Effect According to the above configuration, when the buffer valve is bent due to the pressure difference between the upper and lower oil chambers, each elastic plate is bent so as to narrow its respective notch. Only bending stress acts, and no distortion occurs.

Furthermore, pressure does not escape from one oil chamber to the other oil chamber through the notch.

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

First, we will begin with the first embodiment shown in FIGS. 1 to 3.

In FIG. 1, 1 is a hydraulic shock absorber for automobiles,
An outer cylinder 2, a cylinder 3 housed within the outer cylinder 2, fixed concentrically thereto, and filled with oil, and a piston rod 4 projecting upward from the outer cylinder 2, with a small-diameter mounting shaft 4 at the lower end.
a and a piston 5 which is fixed to the cylinder 3 and slidably fits into the cylinder 3.

The piston 5 divides the inside of the cylinder 3 into two upper and lower oil chambers 6.7, and the outer cylinder 2 and cylinder 3 define an oil reservoir 8 therebetween. This oil reservoir 8 communicates with the lower oil chamber 7 via an orifice 13.

An upper mounting member 14 is fixed to the upper end of the piston rod 4 for mounting to the vehicle body, and a lower mounting member 15 is fixed to the lower end of the outer cylinder 2 for mounting to the wheel support arm. Upper spring seat 16 formed on the lower surface of 14
A coiled suspension spring 18 is compressed between the lower spring seat 17 and the lower spring seat 17 fixed to the outer periphery of the outer cylinder 2.

In FIGS. 2 and 3, the piston 5 has an oil chamber 6.
．． 7, four first channels 9 and two second channels 1 communicating with each other.
0 is bored, and a first buffer valve 11 that controls the upward flow of oil from the first flow path 9 to generate a contraction damping force when the piston 5 descends, and a first buffer valve 11 that generates a contraction damping force when the piston 5 ascends. , and a second buffer valve 12 that controls the downward flow of oil from the second flow path 10 and generates an extensional damping force.

To explain these structures in more detail, a first valve seat 21 and an annular recess 23 that surrounds this valve seat 21 and opens to the upper oil chamber 6 are formed at the upper end of the piston 5. 2
1 is the outlet of the first flow path 9, and the recess 23 is the outlet of the second flow path 10.
The entrances of each open. Further, a second valve seat 22 and an annular recess 24 that surrounds this valve seat 22 and opens to the lower oil chamber 7 are formed at the lower end of the piston 5. However, the inlets of the first flow paths 9 are opened in the recesses 24, respectively.

Then, on the mounting shaft 4a, upper fulcrum plates 2 are arranged in order from the top.
5. The first buffer valve 11, the piston 5, the second buffer valve 12, and the lower support plate 26 are fitted, and these are fixed to the piston rod 4 by a nut 27 screwed onto the lower end of the mounting shaft 4a.

The 111th valve 11 cooperates with the first valve seat 21 to
The opening and closing of the flow path 9 is controlled, and the second buffer valve 12 is connected to the second valve seat 2.
2 to control the opening and closing of all the second flow paths 10, and these buffer valves 11 and 12 each have a plurality of openings on the outer periphery, as shown in FIGS. 3 and 4. Notch 28
It is constructed by overlapping a plurality of elastic plates 29 made of temporary springs. At this time, the notches 28 of the plurality of elastic plates 29 do not communicate with each other, and the notches 28 of the elastic plates 29 adjacent to the corresponding valve seats 21 and 22 do not communicate with the outlets of the flow paths 9 and 10. It is arranged like this. In order to define such an arrangement, a key groove 30 formed on the outer peripheral surface of the mounting shaft 4a, and a key 32 formed on the periphery of the center hole 31 of each elastic plate 29 that fits into the mounting shaft 4a. is engaged.

Next, the operation of this embodiment will be explained.

When a compressive load in the axial direction is applied to the shock absorber 1 and the pressure in the lower oil chamber 7 rises above a predetermined value, the first shock absorber 11 bends upward about the upper fulcrum plate 25 in response to the pressure rise, and Since the outlet of the first flow path 9 is opened appropriately, the oil in the lower oil chamber 7 flows through the first flow path 9 to the upper oil chamber 6, and the shock absorber 1 contracts as the piston 5 descends.

At this time, the descending speed of the piston 5 is controlled by the damping force generated by the throttling resistance by the eleventh valve 11 of the first flow path 9.

By the way, when the first buffer valve 11 is bent, since the plurality of elastic plates 29 constituting it are each provided with a plurality of notches 28 opening at the outer peripheral edge, the first buffer valve 11 can be bent easily while narrowing the notches 28. , no distortion.

Moreover, since the plurality of elastic plates 29 are positioned so that the respective notches 28 are not communicated with each other or with the first flow path 9, pressure does not escape from the notches 28. As a result, the first buffer valve 11 can accurately respond to the pressure in the lower oil chamber 7 and generate the desired damping force.

Then, when the compressive load is removed, the shock absorber l is suspended from the suspension spring 18.
When the pressure in the upper oil chamber 6 rises to a predetermined value or more, the second buffer valve 12 bends downward about the lower fulcrum plate 26 in response to the rise in pressure, causing the second flow to expand due to the repulsive force. Since the outlet of the passage lO is opened appropriately, the oil in the upper oil chamber 6 flows through the second flow passage 10 to the lower oil chamber 7, and as the piston 5 rises, the shock absorber 1 expands.

At that time, the rising speed of the piston 5 is determined by the second
It is controlled by the damping force generated by the throttling resistance by the buffer valve 12.

In this case as well, the second buffer valve 12 has basically the same configuration as the first buffer valve 11, so it can accurately respond to the pressure in the upper oil chamber 6 and generate the desired damping force. Can be done.

5 to 7 show a second embodiment of the present invention. Parts corresponding to those in the previous embodiment are given the same reference numerals, and only the structures that are different from the previous embodiment will be described.

The piston 5 has a cup shape with an end wall 5a facing upward and has a plurality of through holes 35, and the hollow portion of the piston 5 and the through holes 35 form a flow path 34.

In the hollow part of the piston 5, an upper spacer cylinder 36 is arranged in order from the top.
, an upper fulcrum plate 37, a buffer valve 38, a lower fulcrum plate 39, and a lower spacing cylinder 40, which are connected to the end wall 5 of the piston 5.
The piston rod 4 is fixed to the piston rod 4 by a nut 27, which is passed through the center by a mounting shaft 4a at the lower end of the piston rod 4 along with a, and is screwed onto the mounting shaft 4a.

The buffer valve 38 is constructed by overlapping a plurality of elastic plates 42 made of leaf springs each having a plurality of slit-like cutouts 41 opening on the outer periphery. are staggered. In order to define such an arrangement, a flat surface 4 formed on an example of the mounting shaft 4a is used.
3 and a flat surface 45 formed on one side of the center hole 44 of each elastic plate 42 are engaged.

On the other hand, an annular control wall 4G is formed on the inner circumferential surface of the piston 5, facing the outer circumferential edge of the buffer valve 38 and defining a constricted portion 34a of the flow path 34 therebetween.

The control wall 46 is formed into a chevron-shaped cross section by a flat top a and sloped parts c and c continuous to both sides of the top a, and the top a has a constricted portion facing the outer peripheral edge of the buffer valve 38 in a free state. Minimize the opening degree of 34a.

Therefore, when the shock absorber 1 contracts under the load in the axial direction,
Along with this, the oil in the lower oil chamber 7 passes through the flow path 34 and moves to the upper oil chamber 6, but initially, the throttle part 34a is at the minimum opening degree.
Since the flow of oil is restricted, the pressure in the lower oil chamber 7 increases,
A damping force is generated.

The pressure generated in the lower oil chamber 7 acts on the lower surface of the buffer valve 38, so when the pressure exceeds a predetermined value and rises, the buffer valve 38 bends upward about the upper fulcrum plate 37, and its outer peripheral end is displaced upward in an arc. Then, when the buffer valve 38 comes to face the inclined part of the control wall 46, the opening degree of the throttle part 34a increases, so that the rate of increase in the generated damping force is determined by the increase in the rising speed of the piston 5. decreases accordingly.

Next, when the compressive load is removed, the shock absorber 1 expands due to the repulsive force of the suspension spring (not shown), but when the pressure difference between the sleeve chambers 6 and 7 disappears before the start of expansion, the buffer valve 38 opens. Due to its own restoring force, it immediately returns to its original free state and the opening degree of the constriction portion 34a is minimized again, so that the expansion of the buffer l,
That is, when the piston 5 starts to rise, when the oil moves from the upper oil chamber 6 to the lower oil chamber 7, the flow of oil is throttled by the constriction part 34a, similar to when the shock absorber 1 contracts, so that the upper oil chamber 6 pressure increases and damping force is generated reliably.

Since the oil pressure in the upper oil chamber 6 acts on the upper surface of the buffer valve 38, when the pressure rises above a predetermined value, the buffer valve 38 bends downward using the periphery of the lower fulcrum plate 390 as a fulcrum.
As the amount of deflection increases, in other words, as the descending speed of the piston 5 increases, the opening degree of the throttle portion 34a increases, and the rate of increase in the damping force decreases accordingly.

By the way, when the buffer valve 38 bends upward or downward,
Since the plurality of elastic plates 42 constituting it bend while narrowing the plurality of notches 41, each elastic plate 42 is not distorted. Furthermore, since the respective notches 41 are shifted from each other and do not communicate with each other, pressure does not escape through the notches 41.

C9 Effects of the Invention As described above, according to the present invention, a buffer valve is constructed by overlapping a plurality of elastic plates having a plurality of notches opening at the outer periphery so that the respective notches do not communicate with each other. When the buffer valve is deflected, each elastic plate can be deflected smoothly without causing distortion, and its deflection characteristics are good, so that a stable damping force can always be obtained.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view of a hydraulic shock absorber for an automobile, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. The figure is a cross-sectional view taken along the line ■-■ of FIG. 2, FIG. 4 is an exploded perspective view of the buffer valve, and FIGS. 5 to 7 show the second embodiment of the present invention. 6 is a sectional view taken along the line Vl--Vl in FIG. 5, and FIG. 7 is an exploded perspective view of the buffer valve. ■...Hydraulic shock absorber, 3...Cylinder, 4...Piston rod, 4a...Mounting shaft, 5...Piston, 6
... Upper oil chamber, 7... Lower oil chamber, 9, 10... Channel, 11.12... Buffer valve, 28... Notch, 28.
...Elastic plate, 34...Flow path, 38...Buffer valve, 41
...Notch, 42...Elastic plate patent applicant Kendo Ochiai, agent of Honda Motor Co., Ltd., patent attorney
1) Takashi Naka Aroma 3 Figure 4 Figure 6 Figure 7 Figure 5

Claims (1)

[Claims] A cylinder whose interior is filled with oil, a piston that is slidably fitted into the cylinder and has a flow path that communicates the inside of the cylinder between an upper oil chamber and a lower oil chamber, and a piston that is attached to the piston and has a flow path that connects the upper oil chamber and the lower oil chamber. In a hydraulic shock absorber equipped with a buffer valve that bends to control the opening degree of a flow path according to the pressure difference between chambers, a plurality of elastic plates each having a plurality of notches opening on the outer periphery are A hydraulic shock absorber characterized in that a shock absorber is constructed by overlapping cutouts so that they do not communicate with each other.