JPH0244114Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber that is attached to a vehicle such as an automobile and is suitable for use in damping vibrations.

FIG. 9 shows a hydraulic shock absorber according to the prior art.

In the figure, 1 is a cylinder, 2 is a piston rod that is provided to protrude into the cylinder 1, and 3 is a piston that is fixed to the piston rod 2 and slides along the inner wall of the cylinder 1. and,
The inside of the cylinder 1 is defined by the piston 3 into two cylinder oil chambers A and B (hereinafter simply referred to as oil chambers A and B), and when the piston 3 is displaced as an extension stroke or a contraction stroke, one of the oil chambers is It is configured to provide a vibration damping effect by generating a damping force in the oil flowing from one chamber to the other oil chamber.

Next, the above-mentioned damping force generation mechanism will be explained. 5 and 6 are valve seats formed in an annular shape near the outer periphery of both end surfaces of the piston 3; 7 and 8 are valve seats of the piston 3;
The valve seats 5 and 6 are slightly protruded from the protrusions 7 and 8, respectively. Further, 9 and 10 are disc valves that are fitted into the piston rod 2, and whose inner peripheral edges abut against the protrusions 7 and 8, respectively, and whose outer peripheral edges abut against the valve seats 5 and 6; a spacer 13 that allows the disc valves 9 and 10 to be deformed in a direction away from the valve seats 5 and 6, respectively;
Reference numeral 14 indicates a regulating portion that regulates the degree of opening of each disc valve 9, 10, and the disc valve 9, spacer 11, and regulating portion 13 are connected to one end surface of the piston 3 and the stepped portion 2A formed on the piston rod 2. Also sandwiched between the disc valve 10 and the spacer 1
2. The regulating portion 14 is held between the other end surface of the piston 3 and a lock nut 15 screwed onto the piston rod 2. Each of the disc valves 9, 10
One of the disc valves 9 is made up of two superimposed discs, and the other disc valve 10 is made up of three superimposed discs. The disc valves 9 and 10 come into contact with the protrusions 7 and 8 and the valve seats 5 and 6, respectively, so that annular oil chambers 16 and 17 are formed between the disc valves 9 and 10 and each side end surface of the piston 3. It is formed. Reference numerals 18 and 19 are communicating passages provided in the piston 3, with one communicating passage 18 communicating between the oil chamber A and the annular oil chamber 17, and the other communicating passage 19 communicating between the oil chamber B and the annular oil chamber 17. The communication passages 18 and 19 are provided at an angle with respect to the axis of the piston 3. Furthermore, one or more notches 20 are formed in one side of the valve seat 5 to allow constant communication between the annular oil chamber 16 and the oil chamber A, and constitute an orifice.

The hydraulic shock absorber according to the prior art has the above-mentioned structure, and its operation will be explained next.

Suppose now that the piston 3 is displaced together with the piston rod 2 in the direction of the arrow X in the figure. As a result, the pressure inside the oil chamber A becomes high, and a pressure difference is generated between the oil chamber A and the oil chamber B. Therefore, the oil in the oil chamber A flows from the notch 20 into the annular oil chamber 16, and from the communication passage 19 to the oil chamber B.
flows to Since the flow path area of the notch 20 is narrowed to form an orifice, a predetermined damping force is applied when passing through this portion. When the piston 3 is displaced at high speed, the pressure within the oil chamber A increases, and this pressure is guided into the annular oil chamber 17 and acts on the disc valve 10. When the pressure acting on the disc valve 10 becomes greater than the spring force of the disc valve 10, its outer peripheral edge portion deforms and separates from the valve seat 6. As a result,
It has a two-step characteristic in which the flow path area from the annular oil chamber 17 to the oil chamber B increases and the damping force characteristic changes.

On the other hand, when the piston 3 is displaced in the direction of the arrow Y, contrary to the above, the same operation as described above is performed. However, since the disc valve 10 uses three discs and the disc valve 9 uses two discs, the opening pressure of the disc valve 10 is higher than that of the disc valve 9, and therefore the piston 3 moves in the X direction. The extension stroke of displacement exhibits higher damping force characteristics than the contraction stroke of displacement in the Y direction.

As described above, in the case of the hydraulic shock absorber according to the prior art, the damping force characteristics are different between the case where the oil flow is performed through the notch 20 and the case where the oil flow is performed through the notch 20, and the case where the oil flow is performed through the notch 20.
Since the damping force characteristics change after the valve is opened, the vibration damping effect can be smoothly performed when the valve is installed in a vehicle or the like.

[Problem that the invention attempts to solve]

However, in the conventional hydraulic shock absorber described above, in both the extension stroke and the contraction stroke,
The cutout 20 is used as a common orifice to allow the oil to flow. For this reason, the extension stroke,
There is a problem in that the low-speed damping force in the reduction stroke has the same characteristics. As a result, the number of disc valves 10 on the extension side is made larger than the number of disc valves 9 on the contraction side, and the damping force characteristic in the extension stroke is made higher, and the low speed damping force characteristic by the notch 20 is improved. If the high-speed damping force characteristic is set to be high enough to match the high-speed damping force characteristic on the extension side, the low-speed damping force characteristic becomes too high on the contraction side, and there is a drawback that a low high-speed damping force characteristic cannot be obtained. On the other hand, if the low-speed damping force characteristic due to the notch 20 is set to a low characteristic that matches the high-speed damping force characteristic on the reduction side, the same drawback will occur.

The present invention was devised in view of the problems of the prior art described above, and provides a hydraulic shock absorber equipped with a damping force generation mechanism that allows low-speed damping force characteristics to be set independently on the extension side and contraction side. It's about doing.

[Means for solving problems]

In order to solve the above problems, the configuration adopted by the hydraulic shock absorber according to the present invention includes a cylinder, a piston rod whose tip protrudes into the cylinder, and a piston rod fixed to the tip side of the piston rod. a piston provided in the cylinder and defining the inside of the cylinder into two cylinder oil chambers; a first valve seat provided on each end surface of the piston; and a piston located on the inner diameter side of each of the first valve seats. a first oil chamber formed on both end surfaces of the piston; and a second valve seat located radially outward from each of the first valve seats and provided on both end surfaces of the piston. , a second oil chamber located between each of the first and second valve seats and formed on both end surfaces of the piston, and each of the first oil chambers sandwiching the piston. a communication path bored in the piston so as to communicate with the cylinder oil chamber located on the opposite side; and disks provided on both end surfaces of the piston so as to sit on and off the respective first valve seats. an orifice formed between each of the isk valves and each of the first valve seats, and an orifice formed between each of the isk valves and each of the first valve seats, in order to communicate the valves with the first oil chamber and the second oil chamber; Like sitting down,
It consists of a ring-shaped check valve fitted on the outer periphery of each of the disk valves, and spring means for biasing each check valve in the direction of seating against the second valve seat.

[Effect]

With this configuration, when the piston and the piston rod are displaced to one side of the extension or contraction stroke, the oil from the cylinder oil chamber on one side flows through the communication path and the first oil chamber on the other side. , flows into the second oil chamber through the orifice and moves the check valve away from the second valve seat against the spring means, at which time the first stage is caused by the resistance of the oil flowing through the orifice. generates low-speed damping force.

In addition, when the piston speed becomes high and the pressure in the cylinder oil chamber on one side becomes high, this high pressure is guided to the first oil chamber, and the disc valve on the other side is separated from the first valve seat, and the second stage generates high-speed damping force.

The low-speed damping force in the first stage is determined by setting the flow path area of the orifice formed between each disc valve located on both end surfaces of the piston and the first valve seat. It can be made different from the reduction side.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on FIGS. 1 to 8. Components that are the same as those of the prior art shown in FIG. 9 are given the same reference numerals, and their explanations will be omitted.

First, FIGS. 1 to 6 show a first embodiment of the present invention.

Reference numeral 21 denotes a piston, and a fitting hole 21A for the piston rod 2 is bored in the axial direction of the piston 21, and annular protrusions are formed on both end surfaces of the piston 21 so as to surround the fitting hole 21A. 22 and 23 are formed. 24 and 25 are the protrusions 22 and 23
A first valve seat formed in an annular shape on both end surfaces of the piston 21 is shown, which is located on the outer peripheral side of the piston 21, and a circle formed between the first valve seats 24, 25 and the protrusions 22, 23. The annular recess is a first oil chamber 2 formed in cooperation with disc valves 36 and 37, which will be described later.
6.27.

28, 28, . . . , 29, 29, . . . are second valve seats located radially outward from the respective valve seats 24, 25, located on both end surfaces of the piston 21, and formed at 90 degree intervals. , each valve seat 28, 29
and the first valve seats 24, 25 are four oil chambers 30, 30, ..., 31, 31, formed in cooperation with check valves 38, 39, which will be described later.
...It's becoming...

32, 32,..., 33, 33,... are piston 2
1, and one end side of one communicating path 32 is connected to the piston 21.
It opens into the first oil chamber 26 at one end surface, and the other end opens into the first oil chamber 26 at the other end surface of the piston 21.
It opens into the oil chamber B at a position radially outer than the valve seat 25, and communicates between the oil chambers B and 26. Further, one end side of the other communication passage 33 is located radially outward from the first valve seat 24 on one side end surface of the piston 21 and opens into the oil chamber A, and the other end side is located on the other side end surface of the piston 21. It opens into the first oil chamber 27, and communicates between the oil chambers A and 27.

Furthermore, 34, 34,..., 35, 35,... are the second oil chambers 3 with respect to the first oil chambers 26, 27.
0 and 31, the first valve seat 2
4 and 25, one notch 34 has a larger passage area than the other notch 35, that is, the low-speed damping force characteristic during the contraction stroke is better than the one during the extension stroke. The damping force is set to be lower than the low-speed damping force characteristic.

Next, 36 and 37 indicate small diameter main disc valves, and each of the main disc valves 36 and 37
are fitted into the piston rod 2, their inner peripheral edges abut against protrusions 22 and 23, respectively, and their outer peripheral edges sit on and off the first valve seats 24 and 25, respectively. Then, one of the main disc valves 36 and 37
The one disc valve used has two discs stacked on top of each other, and the other disc valve has four discs stacked on top of each other.

Reference numerals 38 and 39 designate annular check valves, the inner circumferential edge of each of the check valves 38 and 39 is fitted onto the outer circumferential surface of each of the main disc valves 36 and 37 with a small gap, and the other circumferential edge thereof The second valve seats 28 and 29 are seated on and off from each other, and their thickness is determined by the main disc valve 3.
6 and 37 to prevent it from coming off from the main disc valves 36 and 37.

Furthermore, 40 and 41 are large-diameter sub-disk valves, each of which is fitted into the piston rod 2, and whose inner peripheral edge is connected to the spacer 11, along with the main disk valves 36 and 37.
12 and protrusions 22, 23, its outer peripheral edge has the same outer diameter as each check valve 38, 39, and is in contact with the back side of each check valve 38, 39. Each of these disc valves 40, 41 is connected to a check valve 38, 3.
The spring constant of each disc valve 40, 41 is set to a small value so that each check valve 38, 39 can open even when the speed of the piston rod 2 is low. It is set.

Thus, the regulating portion 13, the spacer 11, the sub-disk valve 40, and the main disk valve 36 are held between the one end surface of the piston 21 and the stepped portion 2A of the piston rod 2, and the main disk valve 37, the sub-disk valve 41 , spacer 1
2. The regulating part 14 is held between the other end surface of the piston 21 and the lock nut 15, and the check valves 38 and 39 are connected to the main disc valves 36 and 3.
7, and is fitted on the outer peripheral side of sub disc valve 4.
0,41.

The present embodiment is constructed as described above, and its operation will be described next.

Assume that the piston 3 is displaced together with the piston rod 2 in the direction of the arrow Y in FIG. As a result, the pressure inside the oil chamber B becomes high and a pressure difference occurs between it and the oil chamber A.
The oil in the oil chamber B flows into the first oil chamber 26 through the communication passage 32 and further flows into the second oil chamber 30 through the notch 34. As a result, a predetermined pressure in the second oil chamber 30 acts on the check valve 38, and when the hydraulic pressure acting on the check valve 38 becomes greater than the spring force of the sub-disc valve 40, it is bent, and the check valve 38 is bent. is the second valve seat 2
8 and becomes the state shown in Fig. 5.

As a result, the flow path from oil chamber B to oil chamber A is opened, and at this time, the notch 34 is designed to have a flow path area that matches the low-speed damping force characteristics in the reduction stroke. When the oil fluid flows,
A predetermined reduction-side low-speed damping force can be obtained.

Then, when the displacement speed of the piston 3 becomes high, the pressure in the oil chamber B increases, this pressure is guided into the first oil chamber 26, and the main disk valve 3
6. When the pressure acting on the disc valve 36 becomes greater than the spring of the disc valve 36, its outer peripheral edge bends and separates from the first valve seat 24, resulting in the state shown in FIG. 6. As a result, the first
The flow path area from the second oil chamber 26 to the second oil chamber 30 increases, and a predetermined reduction-side high-speed damping force characteristic is generated, resulting in two-stage characteristics as a whole.

On the other hand, even when the piston 3 is displaced in the direction of the arrow X, contrary to the above, the oil chamber A
The oil flows into the first oil chamber 27 from there and performs the same action as described above. At this time, the low-speed damping force characteristics in the extension stroke can be appropriately set by the flow path area of the notch 35.

In addition, in the case of this embodiment, the check valve 38,
The thickness dimension of 39 is the main disc valve 36,3
Slightly larger than the thickness dimension of 7, and regulating part 1
3 and 14, it is possible to prevent the main disk valves from falling off from the main disk valves 36 and 37.

Next, FIG. 7 shows a second embodiment of the present invention,
The feature of this embodiment is that the spacers 11 and 12 are eliminated, and the restricting parts 51 and 52 have protruding parts 51 located on the inner diameter side and holding the main disc valves 36 and 37.
A, 52A is formed. On the other hand, the sub disc valves 40 and 41 are abolished and the slide valves 53 and 54 are slidably fitted into the protrusions 51A and 52A,
The respective slide valves 53, 54 and the regulating portion 51 are located on the back side of the respective slide valves 53, 54.
52, coil springs 55 and 56 are stretched between the coil springs 55 and 52.

Although the present embodiment is constructed as described above, its operation is the same as that of the first embodiment.

However, by configuring as in this embodiment,
Since the coil springs 55 and 56 can be selected with appropriate spring constants, the opening pressure of the check valves 38 and 39 can be reduced compared to the first embodiment using the sub-disk valves 40 and 41. It can be set to an even smaller value. On the other hand, the slide valves 53 and 54 can also serve as a back pressure prevention plate, and the main disc valves 36 and 3
7. The durability of the check valves 38, 39, etc. can be improved.

Although each embodiment of the present invention has been described above, it goes without saying that the number of disks in the main disk valves 36 and 37 can be set to an appropriate number. Also, the second
The number of oil chambers 30, 31, communication passages 32, 33, etc. is 4.
It is not limited to 1, but may be an appropriate number. Furthermore, as shown in FIG. 8, a common orifice 61 is formed on the second valve seat 28 (29) on the extension side and the contraction side,
If the flow path area of the orifice 61 is set smaller than the flow path area of the notch 34, the low speed damping force characteristic can be reduced to 2.
It is possible to obtain three stages of damping force characteristics as a whole.

[Effect of idea]

The hydraulic shock absorber according to the present invention is as described in detail above, and has first shock absorbers provided on both end surfaces of the piston.
An orifice is formed between the valve seat and the disc valve, which determines the low-speed damping force characteristics.
Since the configuration is such that a check valve is provided on the outer peripheral side of each of the disc valves so as to be seated on the second valve seat by a spring means, the flow path area of each of the orifices can be appropriately set. This allows the low-speed damping force characteristics on the extension side and contraction side to be set to a desired value, and since the check valve is fitted on the outer circumferential side of the disc valve, it is possible to set the low-speed damping force characteristics on the extension side and contraction side to a desired value. The check valve's spring constant can be set to an appropriately small value by means of a spring means provided on the back side of the check valve. This increases the degree of freedom when setting low-speed damping force characteristics.

[Brief explanation of drawings]

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is a half-sectional view of the main part of a hydraulic shock absorber, and FIG.
The figure shows the piston in Figure 3 or 4.
A sectional view in the direction of the arrow, Figure 3 is a left side view of Figure 2,
Fig. 4 is a right side view of Fig. 2, Fig. 5 is an explanatory diagram showing the state in which the check valve on the reduction side is open, and Fig. 6 is an illustration showing the state in which the check valve and disc valve on the reduction side are opened. FIG. 7 is a half-sectional view of the main part showing the second embodiment of the present invention, and FIG. 8 is the first embodiment.
FIG. 3 is a partial view showing a modification of the embodiment, and FIG. 9 is a longitudinal sectional view of a main part showing a hydraulic shock absorber according to the prior art. 1...Cylinder, 2...Piston rod, 1
1, 12...Spacer, 13, 14, 51, 52
...Regulation part, 21...Piston, 22, 23...
Projection, 24, 25...first valve seat, 26, 2
7... First oil chamber, 28, 29... Second valve seat, 30, 31... Second oil chamber, 32, 33...
Communication path, 34, 35...notch (orifice),
36, 37... Main disc valve (disc valve), 38, 39... Check valve, 40,
41... Sub disc valve, 53, 54... Slide valve, 55, 56... Coil spring.

Claims (1)

[Claims for Utility Model Registration] (1) A cylinder, a piston rod whose tip protrudes into the cylinder, and two piston rods which are fixedly attached to the tip of the piston rod and which move the inside of the cylinder. A piston defined in a cylinder oil chamber, a first valve seat provided on both end surfaces of the piston, and a first valve seat located on the inner diameter side of each first valve seat and formed on both end surfaces of the piston. a first oil chamber; a second valve seat located radially outward from each of the first valve seats and provided on both end surfaces of the piston;
a second oil chamber located between the first valve seat and the second valve seat and formed on both end surfaces of the piston, and a second oil chamber sandwiching the piston between the first oil chambers a communication passage bored in the piston so as to communicate with the cylinder oil chamber located on the opposite side; and a disc valve provided on both end surfaces of the piston so as to sit on and off from each of the first valve seats. and an orifice formed between each of the disc valves and each of the first valve seats in order to communicate the first oil chamber and the second oil chamber, and an orifice formed between each of the disc valves and each of the first valve seats, a ring-shaped check valve fitted on the outer peripheral side of each of the disc valves so as to be seated and separated;
a hydraulic shock absorber comprising spring means for biasing each of the check valves in a direction in which they are respectively seated with respect to the second valve seat; (2) The hydraulic shock absorber according to claim (1), wherein each of the spring means is a sub-disk valve whose inner circumferential side is fixed and whose outer circumferential side presses the back side of each of the check valves. (3) Each of the spring means is composed of a slide valve located on the back side of each of the disk valves and check valves, and a coil spring that presses each slide valve against the back side of each of the check valves. Hydraulic shock absorber according to claim (1) of patent registration.