JPH06280920A - Nonreturn valve leaf spring of hydraulic buffer - Google Patents

Abstract

PURPOSE:To secure comfortableness for a car by smoothing the opening motion of a non-return valve when a hydraulic buffer is in reversal of the stroke, minimizing the pressure change likely generated in an upper or a lower oil chamber, and removing turbulence in the elongation side and compression side damping force in the initial period of generation. CONSTITUTION:A leaf spring 4 for non-return valve is formed in a flat plate in such an arrangement that the spring 4 will not give initial load to the valve. A plurality of resilient legs 1-3 are formed at the peripheral edge of this spring 4, and therein the spacing theta1-theta2 of the legs 1-3 in the circumferential direction, the length L in the radial direction, or the width B are selected appropriately or in proper combination, or the shape of the peripheral edge of the spring 4 is formed so that the length from the center of mounting to the peripheral edge is not uniform in the circumferential direction. Thereby the leaf spring 4 is given a defference in the deflective stiffness in the circumferential direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber used for a suspension system in a traveling vehicle such as a motorcycle or an automobile, and more particularly to improvement of a leaf spring for a non-return valve in the hydraulic shock absorber.

[0002]

2. Description of the Related Art FIG. 8 shows a multi-cylinder type hydraulic shock absorber that has been widely and generally used as a shock absorber for automobiles, and the hydraulic shock absorber 20 includes a cylinder 21 having a cylindrical shape. A cylindrical outer shell 22 that is concentrically arranged around the cylinder 21, a piston 23 that is slidably inserted into the cylinder 21, and a base that is located at the lower end of the cylinder 21 and is interposed between the outer shell 22 and the outer shell 22. And a valve 24.

A piston rod 25 extends upward from the piston 23. The piston rod 25 is guided by a bush (not shown) provided in a seal case 26 and is kept under an oil-tight condition. And penetrates the seal case 26 and extends to the outside of the cylinder 21.

Thus, the piston 23 is the cylinder 21.
The inside is partitioned into an upper oil chamber A on the piston rod 25 side and a lower oil chamber B on the base valve 24 side, and the base valve 24 separates this lower oil chamber B from the reservoir chamber C between the cylinder 21 and the outer shell 22. is doing.

The piston 23 which divides the upper oil chamber A and the lower oil chamber B has a concentrically arranged extension side port 27 and compression side port 28, and is fixed to the lower end of the piston rod 25 by a piston nut 29. ing.

The lower end of the expansion side port 27 is closed by an expansion side main valve 31 urged by a main spring 30, and the upper end of the compression side port 28 is elastically bent downward. Leaf spring 3 with legs 32
It is blocked by the non-return valve 34 under the force of 3.

On the other hand, the base valve 24 also has the expansion side port 35 and the compression side port 36 which are concentrically arranged like the piston 23, and the cylinder 21 and the outer shell 2 are provided.
It is located on a cap 37 that closes the lower end of 2, and is clamped and fixed by the cylinder 21.

The extension side port 35 of the base valve 24
The upper end of is closed by a non-return valve 38 urged by a leaf spring 33 having a plurality of elastic legs 32 bent downward similarly to the pressure side port 28 on the piston 23 side. The lower end of the port 36 is closed by a pressure side main valve 39, which is a leaf valve and has a fixed inner circumference.

Thus, during the extension stroke of the hydraulic shock absorber 20 in which the piston rod 25 comes out of the cylinder 21, the working oil in the upper oil chamber A causes the main valve 31 to flow from the extension side port 27 of the piston 21. The extension side damping force corresponding to the extension speed at that time is provided by the flow resistance of the hydraulic oil that flows by opening and opening the main valve 31 while pushing open against the restoring force of the main spring 30. Occur.

In parallel with this, the piston rod 2
An amount of hydraulic oil corresponding to the exit volume of 5 is stored in the reservoir chamber C.
Through the expansion side port 35 of the base valve 24, the non-return valve 38 is opened while the elastic leg 32 of the leaf spring 33 is flexed, and the lower oil chamber B is replenished with almost no resistance.

On the contrary, when the hydraulic shock absorber 20 shifts to the compression stroke from this state, the working oil in the lower oil chamber B this time flows from the pressure side port 28 of the piston 23 to the leaf spring 33.
The non-return valve 34 is opened while bending the elastic leg 32 of No. 2 and flows into the upper oil chamber A with almost no resistance.

However, at this time, since the amount of hydraulic oil corresponding to the intrusion volume of the piston rod 25 into the cylinder 21 cannot be completely accommodated in the upper oil chamber A, the base valve 2
The hydraulic oil for this amount also flows from the pressure side port 36 of No. 4 to the reservoir chamber C while bending and pressing open the pressure side main valve 39 fixed to the inner circumference, and pushing and opening the pressure side main valve 39 to pass therethrough. The fluid flow resistance generates a damping force on the compression side according to the compression speed at that time.

FIG. 9 shows a hydraulic shock absorber that is widely used as a front fork for supporting the front wheels of a motorcycle.
An outer tube 41 located above, a double-cylinder type hydraulic shock absorber 42 slidably inserted into the outer tube 41 while maintaining an oil tight state, and between the hydraulic shock absorber 42 and the outer tube 41. And a suspension spring 43 interposed between the two.

A piston rod 44 extends upward from the hydraulic shock absorber 42, and a tip end of the piston rod 44 is connected to a fork bolt 60 screwed to an upper end of the outer tube 41 by a screw connection. I am doing it.

The hydraulic shock absorber 42 is provided with an axle bracket 45 attached to the lower end by a screw coupling means, and the axle bracket 45 supports the front wheel shaft of the motorcycle, and thus the suspension spring 43 is attached to the front wheel.
Restoring force elastically supports the vehicle body.

On the other hand, the hydraulic shock absorber 42 includes a cylindrical cylinder 46, a cylindrical outer shell 47 which is also concentrically arranged around the cylinder 46, and a piston 48 slidably inserted into the cylinder 46. , And the base valve 4 arranged at the lower end of the cylinder 46.
9 and 9.

The piston rod 44 is guided from the piston 48 by a bush 61 provided in a seal case 50, and the seal case 5 is kept under an oil-tight condition.
It extends through 0 to the outside of the cylinder 46.

Thus, the piston 48 and the cylinder 46
The inside is divided into an upper oil chamber A on the piston rod 44 side and a lower oil chamber B on the base valve 49 side, and the base valve 49 isolates this lower oil chamber B from the reservoir chamber C between the cylinder 46 and the outer shell 47. is doing.

The piston 48, which divides the upper oil chamber A and the lower oil chamber B from each other, has two sets of port groups, that is, an expansion side port group and a compression side port group which are alternately arranged on a concentric circle. ) 51, and is fixed to the lower end of the piston rod 44 by a piston nut 52.

Of the two sets of port groups 51, the lower end of the expansion side port group is closed by an expansion side main valve 53 that is fixed to the inner circumference and is sandwiched between the piston 48 and the piston nut 52. The upper end of the group is closed by a non-return valve 56 under the bias of a leaf spring 55 having a plurality of elastic legs 54 bent downward.

On the other hand, the base valve 49 also has two sets of expansion side port groups and compression side port groups (only the expansion side port group is shown in the figure) 57 alternately arranged on the concentric circles, like the piston 48. is doing.

The upper end of the expansion side port group of the base valve 49 is biased by a leaf spring 55 having a plurality of elastic legs 54 bent downward, like the pressure side port group on the piston 48 side. It is closed by a return valve 58, and the lower end of the pressure side port group is closed by a pressure side main valve 59, which is a leaf valve and has a fixed inner circumference.

Thus, during the extension stroke of the front fork 40, the working oil in the upper oil chamber A of the hydraulic shock absorber 42 bends the main valve 53 downward from the extension side port group of the piston 48 and pushes it open. While flowing to the lower oil chamber B, the extension side damping force corresponding to the extension speed at that time is generated by the flow resistance of the operating oil that pushes and opens the main valve 53.

In parallel with this, the piston rod 4
The amount of hydraulic oil corresponding to the exit volume of 4 is stored in the reservoir chamber C.
Through the expansion side port group of the base valve 49, the non-return valve 58 is opened while the elastic leg 54 of the leaf spring 55 is bent, and the lower oil chamber B is replenished with almost no resistance.

On the contrary, from this state, the front fork 40
Is turned to the compression stroke, this time the hydraulic oil in the lower oil chamber B of the hydraulic shock absorber 42 opens the non-return valve 56 while bending the elastic leg 54 of the leaf spring 55 from the pressure side port group of the piston 48. It flows into the upper oil chamber A with almost no resistance.

However, at this time, since the amount of hydraulic oil corresponding to the intrusion volume of the piston rod 44 cannot be completely accommodated in the upper oil chamber A, the hydraulic oil corresponding to that amount is also supplied from the pressure side port group of the base valve 49. , Pressure side main valve 59 with fixed inner circumference
Flows downward into the reservoir chamber C while pushing it open, and the flow-side resistance of the hydraulic oil passing through the pressure-side main valve 59 pushes it open to generate a compression-side damping force corresponding to the compression speed at that time.

Although the front fork for suspending the front wheel of the motorcycle has been described above, the basic structure of the double-cylinder type hydraulic shock absorber for suspending the rear wheel of the motorcycle is first described. It is basically the same as the shock absorber for an automobile described with reference to FIG. 8 and whether or not it has a suspension action (presence or absence of a suspension spring), and basically there is no change.

[0028]

As described above, in conventional shock absorbers for automobiles and hydraulic shock absorbers for front forks and rear wheel suspensions in motorcycles, the leaf spring 3 for the non-return valve is used.
A plurality of elastic legs 3 simply bent downward as 3,55
2, 54, the elastic legs 32, 54 are evenly pressed against the non-return valves 34, 38, 56, 58, so that the non-return valves 34, 38, 56,
I tried to keep 58 closed.

Therefore, when these hydraulic shock absorbers shift from the expansion stroke to the compression stroke, or vice versa, from the compression stroke to the expansion stroke, the non-return valves 34, 38, 56, 58 cause the elastic legs 32, 35 of the leaf springs 33, 35 to move. 54 is bent to the upper side and suddenly becomes a fully open state. As a result, a large pressure fluctuation occurs in the upper oil chamber A or the lower oil chamber B, and turbulence occurs at the initial stage of generation of the extension side and the compression side damping force. However, there is an inconvenience that it adversely affects the vibration damping action of the vehicle and impairs the riding comfort of the vehicle.

Therefore, an object of the present invention is to smooth the opening operation of the non-return valve when the stroke of the hydraulic shock absorber is changed to minimize the pressure fluctuation occurring in the upper oil chamber or the lower oil chamber, and to reduce the expansion side and compression side damping. (EN) A leaf spring for a non-return valve of a hydraulic shock absorber of this kind, which is capable of eliminating turbulence at the initial stage of force generation and ensuring a comfortable riding comfort of a vehicle.

[0031]

In order to achieve the above object, according to the present invention, a leaf spring for a non-return valve is formed in a flat plate shape, and the leaf spring applies an initial load to the non-return valve. Is configured not to give.

A plurality of elastic legs are formed on the outer peripheral edge of the leaf spring, and the intervals, the radial lengths, or the widths of the elastic legs in the circumferential direction are appropriately selected or combined, or, The outer peripheral edge shape of the leaf spring is appropriately formed unevenly in the length from the mounting center to the outer peripheral edge along the circumferential direction.

Thus, the leaf springs are configured to have a difference in flexural rigidity around the circumferential direction.

[0034]

Thus, according to the present invention, the leaf spring does not apply an initial load to the non-return valve, so that the hydraulic shock absorber is in the process of changing the stroke from the extension stroke to the compression stroke or from the compression stroke to the extension stroke. The non-return valve starts to open immediately and keeps pressure fluctuations occurring in the upper oil chamber or the lower oil chamber as small as possible.

After the non-return valve begins to open, the non-return valve opens sequentially with a time delay from the portion facing the portion of the leaf spring which is unbalanced around the circumferential direction and has a small bending rigidity.

Therefore, when the stroke of the hydraulic shock absorber is changed, the opening of the non-return valve is smoothed to reduce the pressure fluctuation occurring in the upper oil chamber or the lower oil chamber. The turbulence of the vehicle is removed to ensure a comfortable ride of the vehicle.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

In FIG. 1, a leaf spring 4 for a non-return valve is formed by a flat ring having three elastic legs 1, 2 and 3 on its outer circumference, and the radii of these elastic legs 1 to 3 are formed. An example is shown in which only the interval θ in the circumferential direction is “θ1>θ2> θ3” while keeping the direction length L and the width B the same.

According to the leaf spring 4 described above, the distance θ in the circumferential direction between the elastic legs 1 to 3 is “θ1>θ2> θ”.
3 ", the leaf spring 4
When each is installed in the hydraulic shock absorber
No. 3 contacts the non-return valve at an unequal interval without applying an initial load.

As a result, when the stroke of the hydraulic shock absorber is changed, the non-return valve starts to open immediately while flexing the elastic legs 1 to 3 of the leaf spring 4, and from the beginning of this opening, the elastic legs of the leaf spring 4 start to open. 1-3
Due to that, you will be limited in its opening.

However, since the distance θ between the elastic legs 1 to 3 in the circumferential direction is different from “θ1>θ2> θ3”, the portion of the non-Ritatan valve facing the portion having the large distance θ. Since the supporting span becomes longer as it goes to the portion, it is easily bent.

Therefore, in the non-return valve, the portion facing the space between the elastic legs 1 and 2 having the largest distance θ1 is largely bent and opens rapidly, and then the portions facing the distance θ2 and the distance θ3 are arranged in this order. It will open to the fully open state while opening late.

In FIG. 2, only the radial length L is set to "L1>L2>L3" while keeping the width B of the elastic legs 1 to 3 and the circumferential distance .theta. In the leaf spring 4 the same. Only the points differ from the previous embodiment of FIG.

Therefore, according to the leaf spring 4 of this embodiment, the length L of each elastic leg 1 to 3 in the radial direction is "L1."
>L2> L3 ”, the flexural loads W of the elastic legs 1 to 3 and the spring constant k are different from each other.

That is, the bending load W of the elastic legs 1 to 3 is smaller as the elastic leg 1 having the longest radial length L1 becomes larger, and then becomes larger in the order of the elastic leg 2 and the elastic leg 3, and similarly the spring constant k. Also, the elastic leg 1 having the longest radial length L1 becomes smaller, and then the elastic leg 2 and the elastic leg 3 become larger in this order.

As a result, when the stroke of the hydraulic shock absorber is changed, the non-return valve first moves to the leaf spring 4.
As soon as the elastic legs 1 to 3 of the leaf spring 4 are flexed, the elastic legs 1 to 3 of the leaf spring 4 are opened.
What is limited by ~ 3 to its opening is
This is similar to the case of the embodiment shown in FIG.

However, after the non-return valve starts to open, the elastic legs 1 to 3 have the longest radial length L1 because of the difference in the bending load W and the spring constant k of the elastic legs 1 to 3 as described above. The portion facing 1 is largely bent and opens quickly, and then the portion facing the elastic leg 2 and the elastic leg 3 is slowly opened in this order and reaches the fully opened state.

In FIG. 3, only the width B is set to "B1 <B2 <B3" while keeping the circumferential distance .theta. And the radial length L of the elastic legs 1 to 3 of the leaf spring 4 the same. An example of the case is shown.

According to the leaf spring 4, since the widths B of the elastic legs 1 to 3 are different from each other by "B1 <B2 <B3", the radial lengths of the elastic legs 1 to 3 described above are different. As in the case of the embodiment of FIG. 2 in which L is given a difference, these elastic legs 1 to
The bending load W and the spring constant k of No. 3 are smaller in the elastic leg 1 having the narrowest width B1, and then increase in the order of the elastic leg 2 and the elastic leg 3.

As a result, like the embodiment of FIG. 2 described above,
When the stroke of the hydraulic shock absorber is changed, the non-return valve starts to open immediately while flexing the elastic legs 1 to 3 of the leaf spring 4 and, after the opening starts, the elastic legs 1 to 1.
Since there is a difference in the bending load W and the spring constant k of No. 3, the portion of the narrowest width B1 facing the elastic leg 1 is largely bent and opens quickly, and then the order of the portions of the elastic leg 2 and the elastic leg 3 facing each other. Open late.

In addition to the above, in this embodiment, the intervals S1, S2 and S3 of the three parts of the non-return valve which are not in contact with the elastic legs 1 to 3 are the same as those of the elastic legs 1 to 1 described above. Similar to the embodiment of FIG. 1 in which the circumferential distance θ of 3 is changed, the distance S1 between the elastic leg 1 having the width B1 and the elastic leg 2 having the width B2 is the largest, and then the elasticity of the width B1 is the same. The distance S2 between the leg 1 and the elastic leg 3 having the width B3 and the distance S3 between the elastic leg 2 having the width B2 and the elastic leg 3 having the width B3 become smaller in this order.

Therefore, since the portion having the larger distance is more likely to be bent, the portion facing the elastic leg 1 having the narrowest width B1 is further bent to open quickly, and then the portion facing the elastic leg 2 and the elastic leg 3 is arranged in this order. It will open slowly and reach the fully open state.

Thus, according to each of these embodiments, the non-return valve does not suddenly fully open and reaches the fully open state stepwise without suddenly opening when the stroke of the hydraulic shock absorber is changed.

In each of the above-mentioned embodiments, the case where all the elastic legs are three has been described as an example, but the number of elastic legs is not limited to this.

Further, in each of the above-mentioned embodiments, the distance θ in the circumferential direction of the elastic legs 1 to 3 of the leaf spring 4, the radial length L and the width B are individually set, and they are separately set. Although different cases have been described, the elastic legs 1 to 3 may be configured by appropriately combining the circumferential distance θ, the radial length L and the width B, or the leaves thereof. The valve 4 may be appropriately selected and used so that the individual elastic legs 1 to 3 do not overlap each other.

The leaf springs having a plurality of elastic legs on the outer circumference have been described in the above embodiments, but in the embodiments shown in FIGS. 4, 5, 6 and 7. Instead of this, the outer peripheral edge of the leaf spring 4 is made eccentric (FIG. 4), U-shaped (FIG. 5), fan-shaped (FIG. 6) or elliptical (FIG. 7). 5 are formed so that the lengths from the attachment center O to the outer peripheral edge are uneven along the circumferential direction due to the protrusions 5.

Also in these embodiments, when the stroke of the hydraulic shock absorber is changed, the non-return valve does not receive an initial load from the leaf spring 4, so that the non-return valve immediately starts to open, and after starting to open, the leaf spring 4 starts to open. The portion of the non-return valve that contacts the protruding portion 5 of is affected by the protruding portion 5 of the leaf spring 4.

That is, after the non-return valve starts to open, the bending load inversely proportional to the length from the mounting center O of the leaf valve 4 to the outer peripheral edge is applied to the portion of the non-return valve which contacts the protrusion 5 of the leaf spring 4. W will be added.

Therefore, the non-return valve is deformed according to the bending load of the leaf spring 4 and opens while reaching the fully opened state.

Thus, even in the embodiments shown in FIGS. 4 to 7, the non-return valve does not suddenly open fully but gradually opens in stages to reach the fully open state when the stroke of the hydraulic shock absorber is changed.

Even in each of the embodiments shown in FIGS. 4 to 7, the leaf springs 4 are appropriately stacked and used as in the above-described embodiments of FIGS. 1 to 3. You can also

[0062]

As described above, according to the first aspect of the present invention, the initial load of the leaf spring becomes zero when the non-return valve is closed, and the non-return valve has a slight pressure difference. Since the valve starts to open, a smooth opening operation can be obtained, and the pressure fluctuation at the opening of the non-return valve can be suppressed.

Moreover, since the spring constant of the leaf spring can be set high, the opening speed of the non-return valve can be slowed to suppress the pressure fluctuation.

Thus, when the stroke of the hydraulic shock absorber is changed, the opening degree of the non-return valve does not increase at once from zero to reach the fully opened state, but the fully opened state is continuously averaged and gradually increased. Therefore, the opening is smoothed, and the pressure fluctuation occurring in the upper oil chamber or the lower oil chamber is reduced, thus eliminating the turbulence in the initial stage of the extension side and the compression side damping force generation, and improving the vehicle comfort. It is possible to ensure a comfortable ride.

According to the second aspect of the present invention, the above-mentioned effect is achieved by arranging the shape of the outer peripheral edge of the leaf spring so that the lengths from the mounting center are unequal. be able to.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a leaf spring for a non-return valve according to the first invention.

FIG. 2 is a plan view showing another embodiment of the first invention.

FIG. 3 is a plan view showing another embodiment of the first invention.

FIG. 4 is a plan view showing an embodiment according to the second invention.

FIG. 5 is a plan view showing another embodiment of the second invention.

FIG. 6 is a plan view showing another embodiment of the second invention.

FIG. 7 is a plan view showing still another embodiment according to the second invention.

FIG. 8 is a partially longitudinal front view of a double-cylinder type hydraulic shock absorber used as a shock absorber for an automobile.

FIG. 9 is a partially longitudinal front view of the front fork for the same motorcycle.

[Explanation of symbols]

 B Elastic leg width L Elastic leg radial length θ Spacing of elastic legs in the circumferential direction 1 Elastic leg 2 Elastic leg 3 Elastic leg 4 Leaf spring 5 Projection 34 Non-return valve 38 Non-return valve 56 Non-return valve 58 Non Return Valve

Claims (2)

[Claims] 1. A leaf spring for a non-return valve is formed of a flat ring having a plurality of elastic legs around its circumference, and the elastic legs have a circumferential interval, a radial length,
Alternatively, the leaf spring for a non-return valve of a hydraulic shock absorber is characterized in that the leaf spring is configured to have a difference in flexural rigidity around the circumferential direction by appropriately selecting or combining the widths and changing the width. 2. The outer peripheral edge of the annular flat plate is formed in such a manner that the length from the mounting center of the annular flat plate to the outer peripheral edge is appropriately non-uniform along the circumferential direction, so that there is a difference in flexural rigidity around the circumferential direction. A leaf spring for a non-return valve of a hydraulic shock absorber characterized by being configured.