JPH03340A - Hydraulic shock absorber - Google Patents

Abstract

PURPOSE:To control the throttle part of a passage to a desired opening corresponding to the pressure difference between both oil chambers and obtain a desired attenuating force according to piston speed by giving an optional form to a control wall. CONSTITUTION:When an axial compression load is added to a buffer 1 to lower a piston 5 into a cylinder 3, the oil in a lower oil chamber 7 is moved to an upper oil chamber 6 through a passage 16, while the flow of the oil is throttled by a throttle part 16a having a minimum opening at first between a valve plate 26 and a control wall 28. Therefore, as the oil pressure generated in the lower oil chamber 7 acts on the lower surface of the valve plate 26, the valve plate 26 is distorted upward together with first auxiliary plates 311, 312 with the periphery of an upper supporting point plate 24 as a supporting point, when the oil pressure is increased, and its free end or outer circumferential end is displaced upward, drawing an arc. When the free end of the valve plate 26 is opposite to the inclined part b of the control wall 28, the opening of the throttle part 16a is increased, so that the increasing rate of the generated attenuating force is reduced according to the increase in ascending speed of the piston 5.

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 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, etc. A partition member having a flow path communicating between the two oil chambers and partitioning the two oil chambers, and a buffer valve provided on the partition member to control the flow of oil generated in the flow path. This invention relates to improvements in hydraulic shock absorbers.

(2) Conventional technology Conventionally, this type of hydraulic shock absorber consists of a cylinder filled with oil, which is slidably fitted into the cylinder and partitioned into an upper oil chamber and a lower oil chamber. , a piston as a partition member having a flow path communicating between both oil chambers, and a piston provided on the piston to control the flow of oil that occurs through the flow path between the upper oil chamber and the lower oil chamber when the piston moves up and down. A device equipped with a buffer valve is known (see, for example, Japanese Patent Laid-Open No. 117169/1983).

In this case, the buffer valve includes a valve seat that opens a flow path on the piston, an elastic valve plate that cooperates with this valve seat to open and close the flow path, and an opening regulation that regulates the opening degree of this valve plate. A piston is used in which a member is provided on a piston.

(3) Problems to be Solved by the Invention In conventional hydraulic shock absorbers, when the opening degree of the valve plate is regulated by the opening degree regulating member, the constricted portion of the flow path defined between the valve plate and the valve seat is Since the damping force is constant, the resulting damping force is uniquely determined by the piston speed. However, if the desired damping force can be obtained according to the piston speed, the uses of the shock absorber will be expanded and it will be convenient.

An object of the present invention is to provide a simple and effective hydraulic shock absorber that can meet such demands.

B0 Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention maintains a neutral position during normal times and moves from the neutral position when a pressure difference occurs between the two oil chambers. an elastic valve plate supported by the partition member so as to bend the free end toward the low pressure side; and an elastic valve plate supported by the partition member so as to bend the free end toward the low pressure side, and the partition member stacked on one side of the valve plate to increase the bending strength in one side of the valve plate. The buffer valve includes an elastic auxiliary plate supported by the buffer plate, and a control wall formed on the partition member to define a constricted portion of the flow path between and opposite to the free end of the valve plate. ,
A first feature is that a minute gap is formed between the valve plate and the auxiliary plate, which communicate with the oil chamber in their free state.

The present invention also provides an elastic valve plate supported by the partition member so as to maintain a neutral position during normal times and to deflect the free end from the neutral position toward the low pressure side when a pressure difference occurs between the two oil chambers. , a flexible porous plate, and the valve plate is stacked on one side of the valve plate with the porous plate sandwiched therebetween in order to increase the bending strength in one side of the valve plate, and is supported by the partition member. A second aspect of the present invention is that the buffer valve is constituted by an elastic auxiliary plate and a control wall formed on the partition member to define a constricted portion of the flow path between and opposite to the free end of the valve plate. The characteristics of

Furthermore, the present invention includes an elastic valve plate supported by the partition member so as to maintain a neutral position during normal times, and to deflect the free end from the neutral position toward the low pressure side when a pressure difference occurs between the two oil chambers. , an elastic auxiliary plate stacked on one side of the valve plate and supported by the partition member in order to increase the bending strength in one side of the valve plate; A third aspect of the present invention is that the buffer valve is constituted by a control wall formed in the partition member to define a constricted portion of the flow path in between, and that the auxiliary plate is provided with a through hole that communicates the front and back sides thereof. Features.

(2) Function According to each feature of the present invention, when a pressure difference occurs between the two oil chambers, oil flows from the high pressure oil chamber to the low pressure oil chamber through the flow path, and as a result, the valve plate By bending toward the low pressure side, the free end is displaced on a constant trajectory, and the amount of displacement increases in accordance with the increase in the pressure difference. Since the free end of the valve plate cooperates with the control wall to define the constricted portion of the flow path, by giving the control wall an arbitrary shape, a desired shape corresponding to the amount of displacement of the free end of the valve plate can be obtained. The desired damping force can be obtained by controlling the opening of the throttle section.

In addition, especially when the valve plate bends toward the auxiliary plate, the flexural strength of the valve plate is increased by the auxiliary plate, so the thickness of the auxiliary plate,
Desired damping force characteristics can be obtained by selecting the length of the flexible arms and the number of flexible arms used.

Furthermore, according to the first feature of the present invention, in the free state of the valve plate and the auxiliary plate, there is a minute gap between them that communicates with the oil chamber, so the oil chamber on the auxiliary plate side becomes high pressure and the valve plate When bending to the low pressure side, the hydraulic pressure on the high pressure side immediately acts on the minute gap and prevents the auxiliary plate from coming into close contact with the valve plate, so the valve plate moves to the low pressure side without being affected by the auxiliary plate. It is possible to flex and exhibit predetermined damping force characteristics.

Furthermore, according to the second feature of the present invention, the hydraulic pressure on the high pressure side also acts between the valve plate and the auxiliary plate through the many holes in the porous plate, so that the valve plate is not affected by the auxiliary plate in this case as well. can be bent toward the low pressure side.

Furthermore, according to the second feature of the present invention, the hydraulic pressure on the high pressure side also acts between the valve plate and the auxiliary plate through the through hole of the auxiliary plate. can be bent to

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

First, we will begin with a first embodiment of the invention shown in FIGS. 1 and 2. In FIG. 1, a hydraulic shock absorber 1 includes an outer cylinder 2, a cylinder 3 housed in the outer cylinder 2 and concentrically fixed thereto, and filled with oil, and protruding upward from the outer cylinder 2. The piston 5 is connected to the piston rod 4 and is slidably fitted into the cylinder 3 as a partition member. 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 between them. Air or an inert gas is sealed in the space above the oil level in the oil reservoir 8 at a predetermined pressure.

The piston 5 has a flow path 16 that communicates between the oil chambers 6 and 7, and when the shock absorber 1 expands and contracts, the flow of oil between the oil chambers 6 and 7 through the flow path 16 is controlled to create a damping force. A buffer valve 9 is provided which generates a .

In addition, the partition member 17 sandwiched between the cylinder 3 and the bottom wall of the outer cylinder 2 prevents the flow of oil between the lower oil chamber 7 and the oil reservoir 8, especially during high-speed expansion and contraction in the shock absorber l. An orifice 10 is provided which generates a damping force in a controlled manner.

An upper mounting member 11 is fixed to the upper end of the piston rod 4 for mounting to the vehicle body, and a lower mounting member 12 is fixed to the lower end of the outer cylinder 2 for mounting to the wheel support arm. Upper spring seat 13 formed on the lower surface of 11
A coiled suspension spring 15 is compressed between the lower spring seat 14 and the lower spring seat 14 fixed to the outer periphery of the outer cylinder 2.

The flow path 16 and the buffer valve 9 will be explained with reference to FIG.

The piston 5 has a cup shape with an end wall 5a facing upward and has a plurality of through holes 20, and the hollow portion of the piston 5 and the through holes 20 constitute the flow path 16.

In the hollow part 21 of the piston 5, in order from above, there is an upper spacing cylinder 22, an adjustment plate 30, an upper support plate 24, and one or more (two in the illustrated example) first auxiliary plates 311, 31! , ultra-thin spacer 33, -valve plates 26, ultra-thin spacer 3
3. One or more (two in the illustrated example) second auxiliary plates 321, 322 and lower spacing plate 23 are housed in close contact with each other, and these are attached to the small diameter of the piston rod 4 together with the end wall aa of the piston 5. The piston 5 is fixed to the piston 5 by a nut 27 which is passed through the center of the end 4a and is screwed into the small diameter end 4a.

The valve plate 26 is made of a leaf spring, and the lower surface skin plate 24.
25, and the upper fulcrum plate 24 is formed to have a larger diameter than the lower fulcrum plate 25. That is, the supporting length of the upper fulcrum plate 24 with respect to the valve plate 26 is set shorter than that of the lower fulcrum plate 25.

Further, each of the auxiliary plates 313, 31t, 32+, and 32□ is also made of a plate spring like the valve plate 26. And the first auxiliary plate 311
．． 31□ is formed to have a smaller diameter than the valve plate 26 and a larger diameter than the upper fulcrum plate 24, and the upper one 31□ is the lower one 31. Formed with a smaller diameter. Also, the second auxiliary plate 32.
．． 32□ is formed to have a smaller diameter than the valve plate 26 and a larger diameter than the lower fulcrum plate 25, and the lower part 32t is formed to have a smaller diameter than the upper part 321.

Further, first and second auxiliary plates 31+, 31z; 32
,．． 32□ are given different diameters,
In the illustrated example, the first auxiliary plates 31+ and 31g correspond to the second auxiliary plates 32. ．． 32 to have a small diameter.

Each spacer 33 also has adjacent auxiliary plates 31, .
The valve plate 2 is formed to have a sufficiently smaller diameter than 321.
A minute gap g is formed between the auxiliary plates 31+ and 32+ adjacent thereto.

On the other hand, on the inner circumferential surface of the piston 5, a constricted portion 16a of the flow path 16 is provided between the outer circumferential end, that is, the free end, of the valve plate 26 and the free end thereof.
An annular control wall 28 is formed that defines a.

The control wall 28 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 is a constricted portion facing the outer peripheral end of the valve plate 26 in a free state. 1
Minimize the opening degree of 6a.

The relative position between the valve plate 26 and the control wall 28 can be adjusted by replacing the adjusting plate 30 with one having a different thickness.

Next, the operation of this embodiment will be explained.

When an axial compressive load is applied to the shock absorber 1 and the piston 5 descends inside the cylinder 3, the oil in the lower oil chamber 7 passes through the flow path 16 and moves to the upper oil chamber 6. Restricted portion 16a between valve plate 26 and control wall 28
Since the flow of oil is restricted, the oil pressure in the lower oil chamber 7 increases,
A damping force is generated.

The oil pressure generated in the lower oil chamber 7 acts on the lower surface of the valve plate 26, so when the oil pressure rises beyond a predetermined value,
As shown in FIG. 3, the valve plate 26 is connected to the first auxiliary plate 311.3.
1□ is bent upward using the peripheral edge of the upper fulcrum plate 24 as a fulcrum, and its free end, that is, the outer peripheral end is displaced upward in an arc. Then, when the free end of the valve plate 26 comes to face the inclined part of the control wall 28, the opening degree of the throttle part 16a increases, so that the rate of increase in the generated damping force increases as the rising speed of the piston 5 increases. decreases accordingly.

Next, when the compressive load is removed, the shock absorber 1 is released from the suspension spring 15.
However, before the elongation begins, both sleeve chambers 6 and 7
When the pressure difference between them disappears, the valve plate 26 and the first auxiliary plate 311.31□ immediately return to the original free state due to their own elasticity and minimize the opening degree of the constricted portion 16a again. 1, that is, when the piston 5 begins to rise,
When oil moves from the upper oil chamber 6 to the lower oil chamber 7, the flow of oil is throttled by the throttle valve 16a in the same way as when the shock absorber l is contracted, so the oil pressure in the upper oil chamber 6 increases and the damping force is ensured. Occur.

Since the oil pressure in the upper oil chamber 6 acts on the upper surface of the valve plate 26, when the oil pressure rises above a predetermined value, the valve plate 26 moves to the second auxiliary plate 32. ．． 32 □ is deflected downward using the peripheral edge of the lower fulcrum plate 25 as a fulcrum, and as the amount of this deflection increases, in other words, as the descending speed of the piston 5 increases, the constricted portion 16
The opening degree of a increases, and the rate of increase in damping force decreases accordingly.

By the way, as described above, the amount of overhang of the valve plate 26 from the lower fulcrum plate 24 is smaller than that from the upper fulcrum plate 25 due to the dimension settings of the lower fulcrum plates 24 and 25. The downward bending load is greater than the upward bending load, and therefore the damping force obtained at this time is greater than when the shock absorber 1 is contracted.

In addition, the first auxiliary plates 311, 312 increase the upward bending strength of the valve plate 26, and the second auxiliary plates 321, 32t increase the upward bending strength of the valve plate 26.
By selecting the thickness, diameter, number, etc. of these auxiliary plates, a desired expansion/contraction damping force can be obtained.

Also, as described above, the first auxiliary plate 31. ．． 31t corresponds to the second auxiliary plate 32. ．． 32. If the valve plate 26 is formed to have a smaller diameter, the upward bending strength of the valve plate 26 will be smaller than the downward bending strength. As a result, the shock absorber 1 exerts a larger damping force when it is extended than when it is contracted.

Furthermore, the valve plate 26 and the auxiliary plates 31+, 312; 32,
．． 32□ in the free state, the valve plate 26 and the auxiliary plate 31 . ．． 32. Since a minute gap g is formed by the spacer 33 between the valve plate 26 and the upper and lower chambers 6,
7, the hydraulic pressure on the high pressure side immediately acts on the small gap g on the high pressure side, causing the auxiliary plate 31. Alternatively, it is possible to prevent the 32□ from coming into close contact with the valve plate 26. Therefore, the valve plate 26 can be bent only with the auxiliary plate on the low pressure side without being affected by the auxiliary plate on the high pressure side.
The damping force can be changed smoothly as shown by the solid line water in the figure.

In this case, if the spacer 33 does not exist and each auxiliary plate 31. , 321 are in close contact with the valve plate 26,
When the valve plate 26 is bent due to the pressure difference between the two chambers 6.7, initially the auxiliary plate 311°31□ or 321.32□ on the high pressure side
At this point, the auxiliary plate on the high-pressure side returns to the free state due to its own elasticity, so a sudden change in the damping force occurs immediately after the expansion/contraction operation is switched, as shown by the dotted line in Figure 6. It turns out.

FIG. 4 shows a second embodiment of the present invention, in which a flexible porous plate 35 is used instead of the spacer 33 to connect the valve plate 26 and the first
．． The structure is the same as that of the previous embodiment except that it is interposed between the second auxiliary plates 31+ and 32+, and in the figure, the same reference numerals are given to the parts corresponding to those of the previous embodiment.

The porous plate 35 is made of rubber or synthetic resin with continuous pores, and the adjacent auxiliary plates 31, . 32. It is formed to have approximately the same diameter. This porous plate 35 includes the valve plate 27 and the auxiliary plate 31. ．． 321, or may be bonded to their opposing surfaces.

According to this embodiment, when a pressure difference occurs between both arm chambers 6 and 7, the hydraulic pressure on the high pressure side is passed through the through hole of the porous plate 35 to the auxiliary plate 31. Alternatively, since it also acts between 32° and the valve plate 26, the valve plate 26 can be bent toward the low pressure side with only the auxiliary plate on the low pressure side without being affected by the auxiliary plate on the high pressure side.

FIG. 5 shows a third embodiment of the present invention, in which each auxiliary plate 31131g, 32 is in direct contact with the valve plate 26 in a free state.
．． ．． The structure is the same as that of the first embodiment, except that a large number of through holes 36 are bored in 32□ to communicate the front and back sides thereof,
In the figure, parts corresponding to the first embodiment are given the same reference numerals. Note that the through hole 36 may be a round hole or a slit, and its shape is free.

According to this embodiment, when a pressure difference occurs between both arm chambers 6 and 7, the high pressure side hydraulic pressure is passed through the numerous through holes 36 to the high pressure side auxiliary plate 31. Alternatively, since it can also be applied between 321 and the valve plate 26, the spacer 3 as in the previous embodiment can be used.
3 and the porous plate 35, the influence of the auxiliary plate on the high pressure side can be eliminated, and the valve plate 26 can be bent toward the low pressure side with only the auxiliary plate on the low pressure side.

Although the embodiments of the present invention have been described in detail above, they can be modified in design without departing from the scope of the claims. For example, a buffer valve 9 may be provided in the partition member 17 instead of the orifice 10, and a spacer 33 may be provided.
Instead, a protrusion or a spacer-like raised portion that contacts the valve plate 26 may be formed on the auxiliary plates 31+, 32+.

Effects of C8 Kaimei As described above, according to the present invention, by giving the control wall an arbitrary shape, the constricted portion of the flow path is controlled to a desired opening degree corresponding to the pressure difference between both oil chambers, and thereby The buffering force characteristics can be freely obtained, and various demands for the buffering force characteristics can be easily met.

A desired damping force can also be obtained by selecting the thickness, length of the flexible arm, and number of auxiliary plates to be used.

Furthermore, when a pressure difference occurs between the two oil chambers, the valve plate can be smoothly bent toward the low pressure side without being affected by the auxiliary plate on the high pressure side, which can contribute to stabilizing the damping force characteristics.

[Brief explanation of drawings]

FIG. 1 is a vertically sectional side view of the essential parts of an automobile hydraulic shock absorber showing a first embodiment of the present invention, FIG. 2 is an enlarged vertical cross-sectional view of the surrounding area of the buffer valve in FIG. 1, and FIG. FIG. 4, which is an explanatory view of the operation of the buffer valve, shows a second embodiment of the present invention, and a sectional view corresponding to FIG. 2, and FIG. 5 shows a third embodiment of the present invention. The cross-sectional view corresponding to the figure, and FIG. 6 is a damping force characteristic diagram of the hydraulic shock absorber. DESCRIPTION OF SYMBOLS 1... Hydraulic shock absorber, 5... Piston as a partition member, 6... Upper oil chamber, 7... Lower oil chamber, 9... Buffer valve, 16... Flow path, 16a.・・Aperture part, 24・・
- Upper fulcrum plate, 25... Lower fulcrum plate, 26... Valve plate, 28... Control wall, 3L, 31□... First auxiliary plate,
321.32□...Second auxiliary plate, 33...Spacer, 34...Minute gap, 35...Porous plate, 36...
・Through hole patent agent Honda Motor Co., Ltd.

Claims (3)

[Claims] (1) At least two oil chambers, a partition member that partitions the two oil chambers by having a flow path that communicates between the two oil chambers, and a partition member that controls the flow of oil generated in the flow path. In a hydraulic shock absorber equipped with a buffer valve, the partition is configured to maintain a neutral position during normal times, and to deflect the free end from the neutral position toward a low pressure side when a pressure difference occurs between the two oil chambers. an elastic valve plate supported by a member; an elastic auxiliary plate stacked on one side of the valve plate and supported by the partition member to increase the strength of deflection in one side of the valve plate; and an elastic auxiliary plate supported by the partition member. a control wall formed on the partition member to define a constricted portion of the flow path between the free end of the buffer valve, 1. A hydraulic shock absorber, characterized in that a minute gap is formed that communicates with the oil chamber in the state of the hydraulic shock absorber. (2) at least two oil chambers, a partition member that partitions the two oil chambers by having a flow path that communicates between the two oil chambers; and a partition member that controls the flow of oil generated in the flow path. In a hydraulic shock absorber equipped with a buffer valve, the partition is configured to maintain a neutral position during normal times, and to deflect the free end from the neutral position toward a low pressure side when a pressure difference occurs between the two oil chambers. An elastic valve plate supported by a member, a flexible porous plate, and stacked on one side of the valve plate with the porous plate sandwiched therebetween in order to increase the bending strength in one side of the valve plate. an elastic auxiliary plate supported by the partition member; and a control wall formed in the partition member to define a constriction of the flow path between and opposite to the free end of the valve plate. A hydraulic shock absorber characterized by comprising a buffer valve. (3) at least two oil chambers, a partition member that partitions the two oil chambers by having a flow path that communicates between the two oil chambers, and a partition member that controls the flow of oil generated in the flow path; In a hydraulic shock absorber equipped with a buffer valve, the partition is configured to maintain a neutral position during normal times, and to deflect the free end from the neutral position toward a low pressure side when a pressure difference occurs between the two oil chambers. an elastic valve plate supported by a member; an elastic auxiliary plate stacked on one side of the valve plate and supported by the partition member to increase the strength of deflection in one side of the valve plate; and an elastic auxiliary plate supported by the partition member. The buffer valve is constituted by a control wall formed on the partition member so as to face the free end of the partition member and define a constricted portion of the flow path therebetween, and the auxiliary plate has a passageway that communicates between the front and back sides of the buffer valve. A hydraulic shock absorber characterized by having holes.