JPH0574735B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic shock absorber that is interposed between a sprung mass and a sprung mass of a vehicle such as an automobile to absorb vertical vibrations generated in the vehicle body. The present invention relates to a compression side damping force fine adjustment mechanism for finely adjusting the compression side generated damping force of the hydraulic shock absorber.

[Conventional technology]

Conventionally, as a fine adjustment mechanism for the damping force generated in a hydraulic shock absorber, as shown in Fig. 6, on the rebound side, a mechanism for setting the initial load in a leaf valve for generating damping force on the rebound side provided in the piston part is used. The lower end of the coil spring is supported by an adjustment nut screwed onto the piston rod.

In addition, for the cylinder, there is a parallel window j ₁ that engages with the adjustment nut when the hydraulic shock absorber is in its most compressed state and restricts the movement of the adjustment nut in the rotational direction.
A collar j having a shape is fixed by a caulking part j'.

Thus, by turning the piston rod from the outside with the hydraulic shock absorber fully compressed and moving the adjustment nut forward and backward relative to the piston rod, the initial load of the coil spring is changed, thereby indirectly reducing the damping generated on the rebound side. I'm making fine adjustments to my power.

On the other hand, on the compression side, the damping force generated on the compression side is finely adjusted by directly changing the deflection load of the leaf valve c for generating the compression side damping force of the base valve portion b.

That is, an adjustment rod d is inserted into the valve case e of the base valve portion b from the outside through a lower cap f that closes the lower ends of the cylinder a and the outer shell a' so as to be vertically movable.

The upper half of the adjustment rod d has a narrow diameter portion _d1 , and this narrow diameter portion _d1 penetrates the valve case e and projects upward.

A spacer i ₁ is provided between the shoulder d ₄ formed on the adjustment rod d by the narrow diameter portion d 1 and _the lower surface of the valve case e.
A valve stopper i and a leaf valve c for generating compression damping force are interposed.

Similarly, a non-return valve h, a spacer h', and a valve stopper are sequentially fitted into the part of the adjustment rod d that protrudes upward from the valve case e, and a nut g is screwed onto the tip _d3 . .

The nut g holds the inner peripheral sides of the leaf valve c and the non-return valve h with respect to the valve case e via the spacer i' and the spacer h' between the nut g and the shoulder part _d4 ,
These are valves whose inner periphery is fixed, and also serve to hold the adjustment rod d itself relative to the valve case e.

On the other hand, the nut g is always fitted into the parallel window _j1 of the collar j to restrict its movement in the rotational direction, and in this state, the inner peripheral side of the leaf valve c is A distance δ is maintained between the lower surface of the inner peripheral side of the valve case e.

As a result, when the lower end operating part _d2 of the adjustment rod d is rotated from the outside using an appropriate tool, the adjustment rod d is screwed into the nut g.
moves up and down relative to the valve case e.

As the adjustment rod d advances and retreats, the leaf valve c
The distance δ between the leaf valve c and the valve case e is changed, and the damping force generated on the compression side is finely adjusted by directly changing the deflection load of the leaf valve c.

[Problem that the invention seeks to solve]

As described above, the mechanism for finely adjusting the damping force generated in the conventional hydraulic shock absorber is performed by adjusting the initial load of the coil spring on the damping force generating leaf valve on the expansion side.

In this way, if the generated damping force is finely adjusted via the coil spring, the spring constant of the coil spring can be set lower than the spring constant of the leaf valve having a leaf spring action.

Therefore, even if the pitch of the threaded portion between the piston rod and the adjustment nut is within the range of a normal thread, it can sufficiently accommodate fine adjustment of the leaf valve.

However, when fine-tuning the generated damping force by changing the deflection load of the leaf valve c itself for generating damping force, such as on the compression side, the deflection load can be adjusted by a slight change in the deflection of the leaf valve c, which has a leaf spring action. will change significantly.

In other words, the tip _d3 of the adjustment rod d and the nut g
Even if the thread in between is made as thin as possible, the pitch is 1 with the minimum M8 size thread, and the deflection change of leaf valve c reaches 1 mm with one rotation of adjustment rod d. .

Therefore, fine adjustment of the compression damping force, which requires adjustment of the initial deflection load in microns, is extremely difficult with this structure alone.

Therefore, as shown in FIG. 6, for example, it is necessary to incorporate an orifice adjustment mechanism into the adjustment rod d in combination with the above structure, and to adjust both together.

However, this requires a high degree of skill and time to match the two and make fine adjustments to the compression damping force.

Moreover, since the adjustment rod d must be hollow and the valve seat and screws must be machined therein, the structure becomes complicated and the cost increases.

Therefore, it is an object of the present invention to finely adjust the compression damping force while operating the adjustment rod with the normal operating amount, while changing the initial deflection load of the leaf valve for generating the compression damping force in small increments. The goal is to make it easy to do.

In addition to the above, in particular, the compression side damping force of a hydraulic shock absorber is relatively simple in structure, and an adjustment rod can be easily incorporated without making any changes to the original mechanism of the hydraulic shock absorber. The purpose is to provide a fine adjustment mechanism.

[Means for solving problems]

The above object is achieved by applying the differential screw principle commonly used in micrometers and the like to the adjusting rod and cleverly incorporating it into the base valve part of the hydraulic shock absorber.

That is, in this invention, a gap is provided between the valve case of the base valve part and the inner peripheral end of the leaf valve for generating damping force, and the adjustment rod is inserted through the valve case, the leaf valve, and the lower cap of the hydraulic shock absorber. Insert.

Nuts are screwed onto the tip and middle portions of the adjustment rod, respectively, and these nuts hold the valve case and leaf valve from both sides to hold the adjustment rod.

On the other hand, in the adjustment rod, there is a difference in the thread pitch between the nut at the tip and the nut at the middle, and the nut at the tip is attached to the collar fixed to the cylinder, and the nut at the middle is attached to the lower cap. engage.

Thus, these collars and the lower cap restrict the movement of each nut in the rotational direction, giving the adjustment rod the function of a differential screw.

[Effect]

As a result, if the adjustment rod is turned clockwise through the proximal end portion exposed to the outside from the lower cap, the nuts (both right-handed threaded) screwed into the tip and middle portions of the adjustment rod will be turned downward. trying to move towards it.

However, since the downward movement of the nut at the tip is prevented by the valve case, the adjusting rod conversely spirals upward in accordance with the thread pitch of the nut at the tip.

On the other hand, the nut in the middle part moves upward as the adjusting rod rotates, and simultaneously moves downward along the adjusting rod according to the thread pitch of the nut. move to.

As a result, if the thread pitch of the nut at the tip is larger, the nut at the tip remains stationary and only the nut at the middle increases the amount of deflection of the leaf valve according to the difference in thread pitch between both nuts. move upwards.

On the other hand, if the thread pitch of the nut at the tip is smaller, the nut at the tip remains stationary and only the middle nut opens the leaf valve according to the difference in thread pitch between the two nuts due to the spring action of the leaf valve. moves downward while decreasing the amount of deflection.

On the other hand, if you turn the adjustment rod counterclockwise in the opposite direction to the above, only the middle nut will move downward or upward while decreasing or increasing the amount of deflection of the leaf valve, depending on the difference in thread pitch between both nuts. and move.

In this way, while rotating the adjustment rod with the normal operating amount, the amount of deflection of the leaf valve is gradually changed using the difference in the thread pitch of both nuts, and the damping force generated on the compression side by the leaf valve is finely adjusted. That's what happens.

Moreover, as mentioned above, while the adjusting rod is configured as a differential screw, the lower cap is simply provided with a means for restricting the movement of the intermediate nut in the rotational direction on the hydraulic shock absorber side. All you need to do is make a simple change.

〔Example〕

FIG. 1 shows a longitudinal section of a main part of a hydraulic shock absorber equipped with a mechanism for finely adjusting the damping force generated on the compression side according to the present invention.

In the above hydraulic shock absorber, inside the cylinder 1,
A piston part 4 that divides the inside of the cylinder 1 into an upper oil chamber C and a lower oil chamber D is slidably inserted, and a piston rod 3 extends upward from the piston part 4 to the outside of the cylinder 1. .

Further, an outer shell 10 is disposed on the outer periphery of the cylinder 1 in a concentric manner, and a reservoir chamber A is defined between the cylinder 1 and the outer shell 10.

The piston portion 4 has a leaf valve 4a for generating a rebound damping force on its lower surface, and a coil spring 4b for setting an initial load interposed between an adjustment nut 4c screwed onto the lower end of the piston rod 3.
is pressed against the lower surface of the piston portion 4 by.

Thus, during the extension stroke of the hydraulic shock absorber,
While pushing open this leaf valve 4a, open the upper oil chamber C.
Flow resistance is applied to the hydraulic oil flowing from the pump toward the lower oil chamber D to generate a rebound damping force.

On the other hand, a collar 12 having two parallel windows 12a and 12b facing the adjustment nut 4c is fixed to the cylinder 1 by a caulking portion 1a.
The adjusting nut 4c engages with the parallel window 12a of the collar 12 (see FIG. 2) when the hydraulic shock absorber is in the most compressed state, and restricts the movement of the adjusting nut 4c in the rotational direction.

Thus, by turning the piston rod 3 from the outside in the state where the hydraulic shock absorber is compressed to the maximum, and moving the adjusting nut 4c forward and backward with respect to the piston rod 3, the initial load of the leaf valve 4a for generating the rebound damping force can be reduced. By changing the spring load of the coil spring 4b to be set, the damping force generated on the rebound side can be finely adjusted.

As described above, the mechanism for finely adjusting the rebound damping force is no different from the mechanism of the conventional example shown in FIG. 6 above.

On the other hand, the compression side damping force fine adjustment mechanism, which forms the characteristic part of the present invention, has a configuration as described below.

That is, as in the conventional example shown in FIG. It is fixed and defines an oil chamber B between it and the lower cap 11.

The oil chamber B has a valve case 20 on one side.
It communicates with the lower oil chamber D through an outer expansion side port 20a and an inner pressure side port 20b bored in the valve case 20, and communicates with the reservoir chamber A through a lower surface notch 20c of the valve case 20.

On the lower surface of the valve case 20, a spacer 22b and a valve stopper 22a with respect to the leaf valve 22 for generating compression-side damping force are sequentially stacked one on top of the other.

Further, a non-return valve 21 having an oil hole 21' and a valve stopper 21a having a notch 21a' are provided on the upper surface, and a non-return spring 21b is provided between the non-return valve 21 and the valve stopper 21a. It has been intervened.

An adjustment rod 23, which serves as a fine adjustment mechanism for the damping force generated on the compression side, is inserted into the cylinder 1 from the outside through the lower cap 11 and the valve case 20 of the base valve section 2. The externally protruding portion is configured as an operating section 23a.

The above configuration is substantially the same as that of the hydraulic shock absorber shown in FIG. 6 previously shown as a conventional example, and there is no difference therebetween.

What is important in this embodiment is that, based on the present invention, the adjustment rod 23 can be easily incorporated as a differential screw without making any changes to the basic structure of the hydraulic shock absorber.

To this end, the adjustment rod 23 of this embodiment, which is a fine adjustment mechanism for the damping force generated on the compression side, has two screws of different pitches, a screw 23c at the tip portion 23b and a screw 23e at the intermediate portion 23d. The pitch of the screws 23c at the tip end 23b is made larger than the pitch of the screws 23e at the intermediate section 23d.

In addition, a nut 2 is attached to the screw 23c of the tip 23b.
4, and a nut 25 is also screwed onto the screw 23e of the intermediate portion 23d, so that these adjustment rods 23
and nuts 24 and 25 constitute a differential screw.

The nuts 24 and 25 cooperate with each other to sandwich the aforementioned valve stopper 22a, spacer 22b, leaf valve 22, valve stopper 21a, and non-return valve 21 from both sides.

In this state, the non-return valve 21 is pressed against the upper surface of the valve case 20 with the inner circumference fixed, and there is a gap δ between the inner circumferential lower surface of the valve case 20 and the inner circumferential side of the leaf valve 22.
It is configured to maintain the .

Thus, the lower oil chamber D in the cylinder 1 is connected from the oil hole 21' of the non-return valve 21 to the pressure side port 20b of the valve case 20 and the leaf valve 2.
2 leads to oil chamber B, and conversely, this oil chamber B is
The expansion side port 20a of the valve case 20 communicates with the lower oil chamber D through the non-return valve 21.

The nut 24 screwed onto the screw 23c of the tip 23b of the adjustment rod 23 is attached to the cylinder 1 at the caulked portion 1.
It is fitted into the parallel window 12b of the collar 12 fixed at point a (see FIG. 2), thereby restricting movement in the rotational direction.

As is clear from FIGS. 1 and 2, the non-fitting portion 12c of the nut 24 in the parallel window 12b connects the oil passage that communicates the lower oil chamber D with the oil chamber below the collar 12. It is configured so that

Similarly, the nut 25 screwed onto the screw 23e of the intermediate portion 23d engages with the parallel window 11a formed in the lower cap 11 (see FIG. 3) to restrict the movement of the nut 25 in the rotational direction. There is.

Thus, if the adjustment rod 23 is turned clockwise through the operating section 23a from the state shown in FIG.
Both nuts 24 and 25 try to move downward through screws 23c and 23e.

However, since the downward movement of the nut 24 is blocked by the valve case 20 via the valve stopper 21a and the non-return valve 21, the adjusting rod 23 will not move according to the pitch of the screw 23c between it and the nut 24. and spiral upward.

On the other hand, the nut 25 moves upward as the adjusting rod 23 rotates and simultaneously moves downward according to the pitch of the screw 23e along the adjusting rod 23. I will have to move.

From this, in FIG. 4, if the adjustment rod 23 is rotated one turn clockwise while restricting the movement of only the nut 24 in the rotational direction, the adjustment rod 23 will move along with the nut 25 according to the pitch of the screw 23c. Move to the left by the dimension 1 ₁ .

That is, the dimension L between the nuts 24 and 25
changes from the initial dimension L ₁ to “L=L ₁ −1 ₁ ”.

However, in reality, the nut 25 is also restricted from moving in the rotational direction, so in addition to the above, the nut 25 moves to the right with respect to the adjustment rod 23 by a distance of ₁₂ , which corresponds to the pitch of the screw 23e. .

As a result, the actual dimension L ₀ between the nuts 24 and 25 after adjustment changes from the initial dimension L ₁ to L ₀ =L ₁ -(1 ₁ -1 ₂ ).

Accordingly, as the adjustment rod 23 rotates, the nut 25 tightens the screw 23c as in the conventional example shown in FIG.
screw 2 without moving only according to the pitch of
3c and the screw 23e, and by gradually changing the amount of deflection of the leaf valve 22 for generating compression side damping force, fine adjustment becomes possible.

From the above, it can be seen that by simply making a simple structural change to the conventional example shown in FIG. 6 by simply forming a parallel window 11a on the inner surface of the lower cap 11, it is possible to solve the problem without changing the other mechanisms inherent in the hydraulic shock absorber.
It will be appreciated that the differential screw adjustment rod 23 according to the invention can be easily incorporated.

The embodiment shown in FIG. 1 is different from the conventional hydraulic shock absorber shown in FIG. 6 in that the non-return valve 21 is pressed onto the valve case 20 by a non-return spring 21b. There is.

On the other hand, in another embodiment of the present invention shown in FIG.
6' non-return valve 26 and spacer 26b
and a valve stopper 26a with an oil hole 26a'.
I am posting this one on top of the other.

By tightening these with nuts 24, the non-return valve 26 is flexed and pressed onto the valve case 20.

As can be seen from FIG. 5, the differential screw type according to the present invention can be applied to a hydraulic shock absorber in which the non-return valve 26 is bent and pressed onto the valve case 20 as in the conventional example. It is clear that the adjusting rod 23 can be easily incorporated.

In addition, in the embodiments so far, both nuts 24,
25 are both right-handed threads, and the nut 2 at the tip
The case has been described in which the thread pitch of the nut 25 is set larger than that of the nut 25 in the middle part.

However, these only select whether to send the intermediate nut 25 upward or downward depending on the operating direction of the adjustment rod 23, and the amount of movement of the intermediate nut 25 is always the same regardless of the direction of operation. It is clear from the above description that this is determined by the difference in the thread pitch of both nuts 24, 25.

Therefore, both nuts 24 and 25 may be both left-handed threaded, or only one of them may be left-handed threaded, or in combination, the thread pitch of the nut 24 at the tip may be smaller than the thread pitch of the nut 25 at the middle part. Needless to say, it is okay.

〔Effect of the invention〕

As described above, according to the present invention, the leaf valve for generating the compression side damping force of a hydraulic shock absorber that finely adjusts the generated damping force by changing the deflection load has a relatively simple structure, and is unique to the hydraulic shock absorber. It becomes possible to easily incorporate an adjustment rod having a differential screw structure without making any changes to the mechanical parts.

Therefore, this differential screw structure makes it possible to easily fine-tune the damping force generated on the compression side by changing the initial deflection load of the leaf valve in small increments while turning the operating rod by the normal operating amount. .

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional front view of the main parts of an embodiment of a hydraulic shock absorber equipped with a mechanism for finely adjusting the damping force generated on the compression side according to the present invention, and FIG. 2 is a vertical sectional view taken from the - line in FIG. FIG. 3 is a cross-sectional plan view taken from the - line, FIG. 4 is an explanatory diagram showing only the adjustment rod taken out, and FIG. 5 is a diagram similar to FIG. 1 showing another embodiment. Main part vertical front view, No. 6
The figure is a longitudinal sectional front view of the main part similar to FIG. 1, showing a conventional example. DESCRIPTION OF SYMBOLS 1...Cylinder, 2...Base valve part, 11...Lower cap, 12...Collar, 20...Valve case, 22...Leaf valve, 23...Adjustment rod, 2
3b...Tip part, 23c...Screw, 23d...Middle part,
23e...Screw, 24...Nut, 25...Nut, δ
…〓A pause.

Claims (1)

[Claims] 1. A space is provided between the valve case of the base valve part and the inner peripheral end of the leaf valve for generating damping force, and an adjustment rod is inserted through the valve case, the leaf valve, and the lower cap. Nuts are screwed into the tip and middle of the adjustment rod, and these nuts hold the valve case and leaf valve from both sides to hold the adjustment rod. The above adjustment is achieved by making a difference in the thread pitch, engaging the nut at the tip with the collar fixed to the cylinder, and the nut in the middle with the lower cap, and regulating the movement of both nuts in the rotational direction. A compression side damping force fine adjustment mechanism for a hydraulic shock absorber, characterized in that the rod is configured as a differential screw. 2. The compression-side damping force fine adjustment mechanism for a hydraulic shock absorber according to claim 1, wherein the thread pitch of the nut at the tip is larger than the thread pitch of the nut at the intermediate part. 3. The compression-side damping force fine adjustment mechanism for a hydraulic shock absorber according to claim 1, wherein the thread pitch of the nut at the tip is smaller than the thread pitch of the nut at the intermediate part.