JP3666961B2 - Damping force generation structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a damping force generation structure used for a hydraulic shock absorber for a vehicle or the like.
[0002]
[Prior art]
For example, various proposals have conventionally been made for hydraulic shock absorbers for vehicles, but in recent years, hydraulic shock absorbers having a damping force generation structure set so that the generated damping force changes depending on the difference in piston speed have been proposed. ing.
[0003]
As an example, for example, in the hydraulic shock absorber shown in FIG. 4, the hydraulic shock absorber is slidably accommodated in the cylinder 1, and is continuously provided at the tip of the piston rod 2 inserted into the cylinder 1 so as to be able to protrude and retract. The piston 3 is provided with a damping valve that constitutes a damping force generating structure adjacent to the first valve 4 that generates an extension side damping force of a predetermined magnitude when the piston speed is in a very low speed range, And a second valve 5 that generates an expansion-side damping force of a predetermined magnitude when the piston speed is in the middle to high speed range.
[0004]
The first valve 4 is composed of an annular leaf valve, and the outer peripheral end is freely fixed by fixing the inner peripheral end while being interposed in the tip inlay portion 2a of the piston rod 2 interposing the piston 3 so as to be in series with the piston 3. The piston 3 is set so as to close the downstream end of the port 3a on the expansion side of the opening so as to be openable and closable.
[0005]
The first valve 4 has a fixed end that is an inner peripheral end sandwiched between an inner peripheral end of the valve stopper 6 on the back pressure surface side and an inner peripheral end of the piston 3 on the pressure receiving surface side, and an outer peripheral end. The free end is arranged so as to be seated on and away from an inner circumferential valve seat portion 3b formed on the piston 3.
[0006]
The state in which the inner peripheral end of the first valve 4 is sandwiched between the piston 3 and the valve stopper 6 is realized by screwing of a piston nut 7 screwed to the tip thread portion 2b of the piston rod 2. A shim 8 is interposed between the upper end of the piston nut 7 and the valve stopper 6.
[0007]
On the other hand, the second valve 5 is composed of an annular plate valve and is arranged in such a manner that it is pressed against the piston 3 by a spring 9 adjacent to the back pressure surface so as to close the downstream side of the first valve 4 so that it can be opened and closed. Is set to
[0008]
The second valve 5 has a sliding end as an inner peripheral end interposed between the guide nut 7a formed on the upper end side of the piston nut 7 so as to be slidable in a liquid-tight state and an outer peripheral end. The free end is disposed so as to be seated and separated on the outer peripheral side valve seat portion 3 c formed on the piston 3.
[0009]
The base end of the spring 9 whose tip is in contact with the second valve 5 is locked to a spring receiving portion 7 b formed at the lower end of the piston nut 7.
[0010]
Therefore, in the hydraulic shock absorber, when the piston 3 moves up in the cylinder 1 and the piston speed is in the very low speed range, the cylinder 1 is partitioned by the piston 3 and is on the high pressure side. The oil from the upper oil chamber U becomes the pressure receiving surface which is the upper surface of the first valve 4 through the port 3a on the extension side, and is bent so that the outer peripheral end of the first valve 4 is lowered. The piston 3 flows into the lower oil chamber L which is partitioned in the cylinder 1 and is on the low pressure side.
[0011]
However, in the hydraulic shock absorber, an orifice 3d is formed in the outer peripheral valve seat portion 3c of the piston 3 on which the second valve 5 disposed downstream of the first valve 4 is seated. Oil through one valve 4 flows out to the lower oil chamber L through the orifice 3d, and at this time, a predetermined amount of damping force on the expansion side is generated in a very low speed region of the piston speed. become.
[0012]
On the other hand, when the piston speed is in the middle and high speed range during the same extension side operation, the first valve 4 is in a so-called open state in which further bending is prevented by the valve stopper 6 as shown in FIG. The second valve 5 descends against the urging force of the spring 9, and the oil from the upper oil chamber U flows out to the lower oil chamber L through the space between the opened valve seat portion 3c, At this time, an extension-side damping force having a predetermined magnitude in the medium to high speed region of the piston speed is generated.
[0013]
As a result, according to the damping force generation structure in the hydraulic shock absorber described above, it is possible to independently set the generated damping force when the piston speed is in the very low speed range and the generated damping force when the piston speed is in the middle speed range. That is, the first valve 4 made of the annular leaf valve is selected to have an appropriate deflection characteristic, and the spring 9 for biasing the second valve 5 is set to an appropriate spring force. By selecting one, it is possible to provide a hydraulic shock absorber that realizes an optimal damping force generation state according to the application.
[0014]
[Problems to be solved by the invention]
However, the following disadvantages are pointed out in the damping force generating structure in the hydraulic shock absorber.
[0015]
First, in order to form the above-described damping force generation structure, the valve stopper 6 and the shim 8 are sequentially assembled after the annular leaf valve as the first valve 4 is provided adjacent to the piston 3. Except when automatically using a machine, when performing manually, that is, manually by an operator, the shim 8 is forgotten, the order of the shim 8 and the valve stopper 6 is wrong, etc. There is an inconvenience that it is difficult to eliminate the so-called installation error.
[0016]
Next, in order to realize the above-described damping force generation structure, it is essential to form a so-called seat surface that adjoins the annular leaf valve that is the first valve 4 at a predetermined position of the piston 3. Since the inner peripheral end of the annular leaf valve is adjacent to the inner peripheral end of the piston 3 and the outer peripheral end is adjacent to the inner peripheral side valve seat portion 3b formed in the piston 3, the inner peripheral side and the outer peripheral side are arranged. It is formed inside and outside.
[0017]
In this case, the inner and outer seat surfaces need to be finished so-called flush with each other within an allowable error range. Therefore, so-called labor is required for processing the piston 3, and the cost of parts is reduced. There is an inconvenience that the cost reduction of the hydraulic shock absorber cannot be expected.
[0018]
In the above damping force generation structure, when the damping force characteristic when the piston speed is in the very low speed range is changed by changing the annular leaf valve that is the first valve 4, There is an inconvenience that the spring 9 for energizing the second valve 5 must be changed.
[0019]
That is, for example, when the annular leaf valve is replaced with a multi-layer structure having a thick wall tendency, or when the annular leaf valve is replaced with a single-layer structure having a thin wall structure, the position of the spring receiving portion 7b in the piston nut 7 is changed. As a result, the spring force in the spring 9 that biases the second valve 5 is changed.
[0020]
Therefore, in order to maintain the damping force characteristic of the second valve 5 at the middle and high speeds of the piston speed as originally set, the valve seat surface position in the outer peripheral valve seat portion 3c is changed accordingly. When the piston 3 is used as it is or when the piston 3 is used as it is, it is necessary to use a separate spring 9 for energizing the second valve 5, resulting in an increase in the number of parts. There is a disadvantage that hinders cost reduction of the hydraulic shock absorber.
[0021]
The present invention has been drafted in view of the above-described circumstances, and the object of the present invention is, of course, that the generated damping force can be set to change depending on the difference in piston speed. When the damping force characteristics are changed when the piston speed is very low, the damping force can be expected to be generated without fear of hindering the cost reduction of the hydraulic shock absorber. Ideal for realizing the desired damping force generation state as a hydraulic shock absorber for vehicles, for example, without fear of changing the damping force characteristics at medium and high speeds of the piston speed without fear of hindering cost reduction It is to provide a damping force generating structure.
[0022]
[Means for Solving the Problems]
In order to achieve the above-described object, the configuration of the present invention is designed so that a damping valve that generates a damping force when a hydraulic pressure is applied from a high pressure side through a port for opening a valve seat member is predetermined when the piston speed is very low. In a damping force generating structure comprising a first valve that generates a damping force of 2 and a second valve that generates a predetermined damping force when the piston speed is in the middle to high speed range, the first valve is disposed on the outer peripheral side. In the parallel state in which the second valve is arranged on the inner peripheral side, the downstream end of the port is closed so that it can be opened and closed, while the first valve is urged by a spring arranged on the low pressure side. The second valve is arranged to be movable while being urged by a spring arranged on the low pressure side, and against the spring of the first valve. Retraction amount and protrusion in the extension direction by the spring are the second To become is regulated by the lube.
[0023]
More specifically, the valve seat member is slidably accommodated in the cylinder and is a piston continuously provided at the tip of the piston rod that is removably inserted into the cylinder. It is assumed that the damping valve is movably disposed on the outer peripheral side of the guide member interposed in series with the piston at the leading inlay portion of the piston rod that interposes the piston.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings. As shown in FIG. 1, a hydraulic shock absorber embodying a damping force generation structure according to the present invention is slidably accommodated in a cylinder 1. An upper-side oil chamber U and a lower oil chamber L are partitioned, and an extension-side damping valve 20 is provided on a piston 3 as a valve seat member connected to the tip of a piston rod 2 inserted into the cylinder 1 so as to be able to appear and retract. Next to it.
[0025]
The damping valve 20 extends the pressure shock absorber as the piston 3 ascends in the upper oil chamber U side, that is, in the cylinder 1, through the expansion side port 3a as a port for opening the piston 3. It is set so that a predetermined extension side damping force is generated when a hydraulic pressure is applied from the high pressure side during the side operation.
[0026]
That is, the damping valve 20 generates a predetermined damping force at the time of the above-described hydraulic action, and generates a predetermined damping force when the piston speed is in a very low speed range, and a predetermined damping force when the piston speed is in a middle speed range. And a second valve 22 to be operated.
[0027]
In the embodiment of the present invention, the damping valve 20 has the first port 21 arranged on the outer peripheral side and the second valve 22 arranged on the inner peripheral side in a parallel state. The downstream end of 3a is set so as to be openable and closable.
[0028]
Further, in the embodiment of the present invention, the damping valve 20 is provided on the outer peripheral side of the guide member 10 that is interposed in series with the piston 3 at the tip inlay portion 2a of the piston rod 2 that interposes the piston 3. It is distributed so that it can move.
[0029]
On the other hand, in the damping valve 20, the first valve 21 is movably held on the outer peripheral side of the second valve 22 while being urged by a spring 23 disposed on the low pressure side which is the lower side in the figure. The second valve 22 is arranged so as to be movable while being urged by the spring 9 disposed on the low pressure side, and the first valve 21 depends on the amount of retreat against the spring 23 and the spring 23. The protrusion in the extending direction is regulated by the second valve 22.
[0030]
To explain a little, the first valve 21 is formed in a substantially cylindrical shape in the illustrated embodiment, and has a valve portion 21a formed in the shape of an outer casing at the upper end and an inner portion on the upper end side. It has a projection 21b formed in the shape of an annular rib on the periphery, and is set in a so-called plate valve shape.
[0031]
Further, the second valve 22 is in the illustrated embodiment, and is formed in a substantially cylindrical shape having a considerably small diameter compared to the first valve 21, and a valve portion 22 a formed in an outer casing shape at the upper end. In addition, it has a threaded portion 22b on the outer periphery on the lower end side, and is similarly set to a so-called plate valve shape.
[0032]
A load ring 24, which is also formed in a substantially cylindrical shape, is disposed between the first valve 21 and the second valve 22, and the load ring 24 is disposed on the inner periphery on the lower end side. 22 includes a threaded portion 24a that is screwed into the threaded portion 22b, and a spring receiving portion 24b that is formed in the shape of an outer casing on the outer periphery of the lower end.
[0033]
The load ring 24 in the illustrated embodiment has an annular seat portion 24c whose tip is adjacent to a leaf spring 25 described later on the outer peripheral side of the lower surface of the spring receiving portion 24b.
[0034]
The spring 23 is interposed between the spring receiving portion 24 b in the load ring 24 and the valve portion 21 a in the first valve 21.
[0035]
Here, when the combination mode of the first valve 21 and the second valve 22 is considered, the outer periphery on the upper end side of the load ring 24 screwed to the second valve 22 is arranged on the inner periphery on the lower end side of the first valve 21. Are slidably contacted.
[0036]
At this time, the valve portion 21a of the first valve 21 is formed on the piston 3 so that the upper surface, that is, the pressure receiving surface, divides the extension side port 3a from the lower oil chamber L by the urging force of the spring 23. It is supposed to be in contact with the sheet portion 3c.
[0037]
At this time, the protrusion 21 b of the first valve 21 is opposed to the upper end of the load ring 24 with an appropriate interval S, and the first valve 21 moves backward against the spring 23. The amount is regulated by the load ring 24, that is, the second valve 22 to which the load ring 24 is screwed.
[0038]
Furthermore, at this time, the protrusion 21b of the first valve 21 is such that the upper surface faces the lower surface of the valve portion 22a of the second valve 22, and thus the freedom of protrusion by the spring 23 of the first valve 21 is restricted. It is going to be.
[0039]
Therefore, the first valve 21 is arranged on the outer peripheral side of the second valve 22 before so-called assembly, and the spring 23 is interposed on the outer peripheral side of the first valve 21. From this state, the load ring 24 is connected to the second valve 22. When screwed into the valve 22, the first valve 21 is movably held on the outer peripheral side of the second valve 22 under the bias of the spring 23, and at this time, the second valve 22 of the first valve 21 is in this state. Therefore, the first valve 21 and the second valve 22 are in an assembled state.
[0040]
As described above, the first valve 21 and the second valve 22, that is, the damping valve 20, is assembled, which contributes to preventing a so-called component misinstallation when the damping force generating structure is realized. Will be able to.
[0041]
As described above, the assembled damping valve 20 is movably disposed on the outer peripheral side of the guide member 10 interposed so as to be in series with the piston 3 at the tip inlay portion 2a of the piston rod 2 at a predetermined position. Is done.
[0042]
Then, a plate spring 25 made of an annular flat plate is interposed in the tip inlay portion 2a of the piston rod 2 so as to be in series with the damping valve 20, and the piston nut 7 is screwed to the tip thread portion 2b of the piston rod 2. The inner peripheral end of the leaf spring 25 is sandwiched between the upper end of the piston nut 7 and the lower end of the guide member 10.
[0043]
At this time, the upper surface of the outer peripheral end as the free end of the leaf spring 25 is adjacent to the tip of the annular seat portion 24 c formed on the lower surface of the spring receiving portion 24 b in the load ring 24 screwed to the second valve 22.
[0044]
When the piston nut 7 is screwed, the spring 9 is disposed on the outer peripheral side of the piston nut 7 and the spring receiver 26 is interposed on the outer periphery of the guide portion 7a formed on the upper end side of the piston nut 7. As a result, the spring 9 is disposed between the spring receiver 26 and the spring receiver 7b formed at the lower end of the piston nut 7. As a result, the damping valve 20 is moved by the spring 9 to the leaf spring 25. Will be urged to rise.
[0045]
At this time, in the damping valve 20, the valve portion 21 a of the first valve 21 is seated on the outer peripheral side seat portion 3 c formed on the piston 3, and the valve portion 22 a of the second valve 22 is formed on the piston 3. It is seated on the inner peripheral side seat portion 3b.
[0046]
Therefore, in the damping valve 20 according to this embodiment, both the first valve 21 and the second valve 22 are only adjacent to a so-called valve seat portion at one location, for example, as shown in FIG. Unlike the first valve 4 in the conventional example, the inner and outer so-called valve seat portions are not adjacent to each other, so that it is not necessary to finish the inner peripheral seat portion 3b and the outer peripheral seat portion 3c in a precise plane. It is possible to eliminate the so-called labor for the processing.
[0047]
When the valve portion 21a of the first valve 21 is seated on the outer peripheral side seat portion 3c formed on the piston 3, the first valve 21 is retracted against the urging force of the spring 23. Accordingly, an initial load due to the spring force from the spring 23 is applied to the first valve 21.
[0048]
In the damping force generating structure in the hydraulic shock absorber according to this embodiment formed as described above, the piston speed is in the very low speed region when the piston 3 moves up in the cylinder 1 and the piston speed is increased. In some cases, as shown in FIG. 2, the oil from the upper oil chamber U which is partitioned by the piston 3 in the cylinder 1 and which is on the high pressure side is the upper surface of the valve portion 21a in the first valve 21 through the port 3a on the expansion side. The piston 3 also reaches the pressure receiving surface, and lowers the first valve 21 against the urging force of the spring 23 through a gap formed between the valve portion 21a and the outer seat portion 3c. The oil flows out into the lower oil chamber L which is partitioned in the cylinder 1 and is on the low pressure side, and at this time, a predetermined amount of damping force on the expansion side is generated in the low speed region of the piston speed.
[0049]
When the piston speed becomes the middle high speed region during the same extension side operation, as shown in FIG. 3, the first valve 21 is lowered by the maximum amount, and the protrusion 21 b of the first valve 21 becomes the upper end of the load ring 24. The second valve 22 is lowered against the urging force of the spring 9 via the leaf spring 25 and the spring receiver 26 together with the load ring 24. Thus, the oil from the upper oil chamber U flows out into the lower oil chamber L through the valve portion 21a of the first valve 21 that is opened to a greater extent and the outer peripheral side seat portion 3c of the piston 3 that is opposed thereto. At this time, a damping force on the extension side having a predetermined magnitude in the medium to high speed region of the piston speed is generated.
[0050]
For this reason, the maximum amount that the first valve 21 can descend when the piston speed is at a very low speed range is formed between the lower surface of the projection 21b of the first valve 21 and the upper end of the load ring 24 below. It is an appropriate interval S, and similarly, the maximum amount that the first valve 21 can be lowered when the piston speed is medium to high is obtained by adding the maximum amount that the second valve 22 can descend to the maximum descending amount of the first valve 21. Of course, it will become a thing.
[0051]
Therefore, according to the damping force generation structure in the hydraulic shock absorber, it is possible to independently set the generated damping force when the piston speed is in a very low speed range and the generated damping force when the piston speed is in a middle speed range. In addition, the biasing force of the spring 23 biasing the first valve 21 and the biasing force of the spring 9 biasing the second valve 22 are each selected to be set to an appropriate spring force. Therefore, it is possible to provide a hydraulic shock absorber that realizes the optimum state of generation of damping force.
[0052]
In the above, the case where the damping force generating structure according to the present invention is embodied in the piston portion of the hydraulic shock absorber is taken as an example. However, according to the intention of the present invention, the base valve portion in the hydraulic shock absorber is described. Of course, the present invention may be embodied, and the action and effect in that case are not different.
[0053]
Moreover, although the hydraulic shock absorber is for vehicles in the embodiment, it is needless to say that the hydraulic shock absorber may be used for other purposes.
[0054]
【The invention's effect】
As described above, according to the present invention, the damping valve that generates the damping force when the hydraulic pressure is applied from the high pressure side through the opening port to the valve seat member has a predetermined damping force when the piston speed is in a very low speed range. And a second valve that generates a predetermined damping force in the middle and high speed range of the piston speed, each of which is urged by a spring disposed on the low pressure side. Since the valve is in a parallel state arranged on the outer peripheral side of the second valve and the downstream end of the port is closed so that it can be opened and closed, the generated damping force can be changed depending on the difference in piston speed. In this case, the generated damping force can be freely set and realized by appropriate selection of the spring force in the springs energizing the first valve and the second valve, respectively.
[0055]
In addition, when the spring force for the spring energizing the first valve is appropriately selected, the effect does not reach the second valve, so the piston speed is very low without causing a design change on the second valve side. The damping force in the region can be changed regardless of the damping force in the middle and high speed regions of the piston speed.
[0056]
The first valve and the second valve are both adjacent to a so-called valve seat portion at one place, and, for example, a valve composed of an annular leaf valve is not adjacent to the inner and outer valve seat portions. Therefore, it is not necessary to finish the outer peripheral side seat part and the inner peripheral side seat part adjacent to each other by the first valve and the second valve, and machining the piston having the outer peripheral side seat part and the inner peripheral side seat part. Therefore, no so-called labor is required.
[0057]
Further, in the present invention, the first valve that constitutes the damping valve is movably held on the outer peripheral side of the second valve that also constitutes the damping valve, and the reverse amount against the spring of the first valve. And, since the protrusion in the extension direction by the spring is restricted by the second valve, the damping valve is assembled, and when the damping force generating structure is embodied in, for example, a hydraulic shock absorber, This can contribute to avoiding so-called misinstallation of parts.
[0058]
As a result, according to the present invention, the generated damping force can be set so as to change depending on the difference in piston speed, so that it is easy to eliminate a so-called misinstallation, and the piston speed is very low. When changing the damping force, there is no risk of changing the damping force characteristics in the middle and high speed range of the piston speed, and it can be expected to generate the damping force as set without fear of hindering the cost reduction of the hydraulic shock absorber. It is optimal for realizing the optimal state of damping force generation according to the application as a hydraulic shock absorber.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view partially showing a hydraulic shock absorber embodying a damping force generating structure according to an embodiment of the present invention.
FIG. 2 is a partial longitudinal sectional view showing, in an enlarged manner, an operating state of the damping force generating structure in FIG. 1 when the piston speed is in a very low speed range.
3 is a partial vertical cross-sectional view showing the operating state of the damping force generating structure in FIG. 1 in the middle and high speed range of the piston speed as in FIG.
4 is a longitudinal sectional view showing a hydraulic shock absorber embodying a conventional damping force generating structure in the same manner as FIG.
5 is a partial longitudinal sectional view showing, in an enlarged manner, an operating state of the damping force generation structure in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston rod 2a Tip inlay part 3 Piston 3a as valve seat member Extension side ports 9 and 23 as ports Spring 10 Guide member 20 Damping valve 21 First valve 22 Second valve

Claims (2)

A damping valve that generates a damping force when hydraulic pressure is applied to the valve seat member from the high-pressure side through the opening port generates a predetermined damping force when the piston speed is in a very low speed range, In a damping force generation structure having a second valve that generates a predetermined damping force in a high speed range, the first valve is disposed on the outer peripheral side and the second valve is disposed on the inner peripheral side The first valve is movably held on the outer peripheral side of the second valve while being urged by a spring disposed on the low pressure side while the downstream end of the port is closed so as to be openable and closable. The valve is arranged to be movable while being urged by a spring arranged on the low pressure side, and the retraction amount against the spring of the first valve and the protrusion in the extension direction by the spring are caused by the second valve. Regulated damping force generation structure The valve seat member is slidably accommodated in the cylinder and the piston is connected to the tip of the piston rod inserted in the cylinder so as to be able to protrude and retract, while the damping valve interposes the piston. 2. A damping force generating structure according to claim 1, wherein the structure is movably disposed on an outer peripheral side of a guide member interposed in series with the piston at a leading inlay portion of the piston rod.

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