JPH0545809B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a damping force adjustment structure for a shock absorber, and in particular to a shock absorber that can change the damping force generated when a piston portion inside a cylinder slides. The present invention relates to an absorber damping force adjustment structure.

[Conventional technology]

From the viewpoint of handling stability and ride comfort, it is preferable that the damping force of a shock absorber installed in a vehicle be changed depending on the driving conditions of the vehicle.

For this reason, various damping force adjustment structures for shock absorbers have been proposed in the past, and it is said that this makes it possible to adjust the damping force as desired.

[Problem that the invention seeks to solve]

However, in conventional proposals of this kind, although the damping force can be adjusted at low piston speeds, it is not possible to adjust it at medium to high piston speeds, or it is possible to adjust the damping force even at medium and high piston speeds. However, the structure for this becomes complicated,
This has the disadvantage of increasing the number of parts and the number of assembly steps.

Therefore, the present invention is capable of effectively adjusting the damping force not only in the low piston speed range but also in the medium and high piston speed range, and the damping force adjustment of the shock absorber can be performed without causing an increase in the number of parts or the number of assembly steps. The purpose is to provide a new structure.

[Means for solving problems]

In order to solve the above problems, the present invention has a structure in which a piston rod is movably inserted into a cylinder via a piston, a piston body partitions an upper chamber and a lower chamber in the cylinder, and an upper chamber is provided in the piston body. A growth side oil passage and a pressure side oil passage are formed to communicate with the lower chamber, and a growth side valve that opens and closes the expansion side oil passage and a leaf valve that opens and closes the compression side oil passage are provided on the end face of the piston body. Adjacent to each other, a side passage communicating between the upper chamber and the lower chamber is provided in the piston rod, a non-return valve for opening and closing the side passage is provided at the bottom of this side passage, and a control valve is provided in the side passage. is rotatably inserted into the shock absorber, and the control valve is formed with an orifice for opening and closing an upper chamber and a side passage. One end of the expansion side slope and the compression side slope are opened at the end faces of the expansion side valve and the leaf valve, respectively, and the other end is connected to the side passage through a port provided in the piston rod and an orifice provided in the rotary valve. It is characterized by being opened and closed.

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

As shown in FIG. 1, a strut-type shock absorber as an embodiment embodying the present invention has a piston portion 3 at the lower end of a piston rod 2 that is slidably inserted into a cylinder 1. It becomes. The inside of the cylinder 1 is divided into an upper chamber A and a lower chamber B by this piston part 3, and by sliding upward from the state shown in the figure, the inside of the cylinder 1 is divided into an upper chamber A and a lower chamber B. It is formed to generate a damping force.

Note that an outer tube (not shown) is formed outside the cylinder 1. A base valve portion (not shown) is fixed to the inner periphery of the lower end of the cylinder 1 to allow communication between the lower chamber B and the reservoir chamber and to generate a compression damping force. .

A through hole 20 is provided in the axial center of the piston rod 2.
A control rod 21 is inserted into the through hole 20. The upper end of the control rod 21 protrudes outside the upper end of the piston rod 2, allowing an appropriate actuator (not shown) or the like to be connected thereto to rotate the control rod 21.

Further, a side passage C is formed inside the piston rod 2 from the lower end to the vicinity of the lower end.
The small diameter portion 22 of the piston rod 2 is provided with ports 23 and 24 that allow communication between the upper chamber A and the side passage C.
is formed.

The piston portion 3 is disposed at the lower end spigot portion 25 of the piston rod 2, and is fixed in a predetermined position by a set nut 4 screwed into the lower end threaded portion 26 of the piston rod 2. It is.

This piston part 3 is a piston main body 3.
0, and a leaf valve 31 serving as an extension valve is adjacent to the lower end surface of the piston body 30.

The leaf valve 31 has an annular seat 32 in contact with the lower surface of its inner circumferential side, and a set nut 4 screwed into the lower end threaded portion 26 of the piston rod 2 so as to press the annular seat 32. The piston body 30 is disposed on the lower surface of the inner circumferential side of the piston body 30 such that the inner circumferential end thereof is fixed. A plate valve 33 is disposed adjacent to the lower surface of the outer peripheral side of the leaf valve 31, and the lower end of the plate valve 33 is brought into contact with the upper end of a spring 34 that is locked to the set nut 4. The outer peripheral end is energized upward.

The piston body 30 has an extension side oil passage 30a formed so as to pass through the piston body 30 in the axial direction to enable communication between the upper chamber A and the lower chamber B, and an extension side oil passage 30a which is formed so as to penetrate the piston body 30 in the axial direction and to allow communication between the upper chamber A and the lower chamber B. The extension side slope 30b is formed to penetrate in an oblique direction to enable communication between the side path C and the lower chamber B. An annular groove 30c is formed on the inner peripheral surface of the piston body 30.
is formed in the annular groove 30c, and the upper end side of the growth-side inclined path 30b opens into the annular groove 30c.

Further, the lower end sides of the extension side oil passage 30a and the extension side inclined path 30b open into respective opening windows 30d and 30e formed in the lower end surface of the piston body 30, respectively. Note that the opening windows 30d and 30e are formed independently by seat portions 30f and 30g that are formed in a rib-like manner to protrude from the lower end surface of the piston body 30, and the seat portions 30f and 30e are formed independently of each other.
At the top of 30g, there are stamping orifices 30f', 30
g′ is formed.

In addition, in this embodiment, the expansion side oil passage 30a
As shown in the upper end view of the piston main body 30 in FIG. 2 and the lower end view of the piston main body 30 in FIG.
As shown in FIG. 3, the opening windows 30d and 30e are also formed in three pieces each, but instead of this, the oil passages and ramps are each made two each, and the opening windows are also made two each. It can be something. In short, leaf valve 3 is the expansion side valve.
1, as long as a pressure receiving surface of a predetermined size is formed on the upper surface thereof.

Note that the line - in FIGS. 2 and 3 indicates that FIG. 1 exists in this cut state, and the line - indicates that FIG. 4 exists in this cut state.

Furthermore, in this embodiment, as shown in FIG. 4, the piston body 30 includes a pressure side oil passage 30h.
A compression side slope 30i is formed in the same manner as the expansion side oil passage 30a and the expansion side slope 30b. However, the difference is that the lower end side of the pressure side ramp 30i opens into the annular groove 30c, and is formed to allow communication between the side channel C and the upper chamber A.

Also, on the upper end surface of the piston body 30,
Similarly to the lower end surface, opening windows 30j and 30k are formed by rib-shaped sheet portions 30l and 30m. And also, the pressure side oil passages 30h and 3
As shown in FIGS. 2 and 3, three opening windows 0i are also formed, and three opening windows 30j and 30k are also formed, corresponding to the number.

In addition, a non-return valve 35 serving as a leaf valve is arranged adjacent to the upper end side of the piston body 30, that is, the upper end side of the pressure side oil passage 30h and the pressure side inclined path 30i.
The outer peripheral end of the piston rod 2 is biased downward by a non-return spring 37 whose upper end is engaged with a stopper 36 which is engaged with the stepped portion 27 of the piston rod 2. And the non-return valve 3
5 is fixed between the upper surface of the inner peripheral end of the piston body 30 and the lower surface of the stopper 36 via the ring seat 38 so that the inner peripheral end is fixed.

Furthermore, stamping orifices 30l', 30m' are formed at the tops of the sheet parts 30l, 30m forming the opening windows 30j, 30k. Further, the stopper 36 is formed with a notch 36'.

A piston ring 39 and a seal 39' are interposed on the outer circumferential surface of the piston body 30 to allow the piston body 30 to slide within the cylinder 1 and to prevent the piston body 30 from moving upwardly within the cylinder 1. It is possible to divide room A and lower room B.

A leaf valve 40, which is a non-return valve, is housed inside the lower end of the set nut 4. The leaf valve 40 is disposed so that its lower surface is in contact with the upper surface of the seat portion 41a of the valve case 41 fixed inside the lower end of the set nut 4. It is biased downward by a spring 43 held at. In addition, the valve case 41 has an expansion side port 41b and a compression side port 4.
1c is formed, and an embossing orifice 4 is formed at the top of the seal portion 41a that partitions the expansion side port 41b.
1a' is formed.

A control valve 5 is rotatably housed in the side channel C. A lower end of a control rod 21 housed in a through hole 20 of the piston rod 2 is connected to the control valve 5. The control valve 5 has a port 2 bored in the piston rod 2.
Orifices 50 and 51 are formed to face the piston rod 2 and the piston rod 2 so as to face the annular groove 30c of the piston body 30.
An orifice 52 is formed that can face the port 28 formed in the spigot part 25 of. The orifices 50, 51, 52 open the ports 23, 52 when the control valve 5 rotates.
24 and 28, respectively, or the opposing sides are blocked, and communication between the side passage C and the upper chamber A and the side passage C
It is formed so as to allow or block communication between the lower chamber B and the lower chamber B. That is, by rotating the control valve 5, the upper chamber A and the lower chamber B can be communicated with each other via the side passage C, and the communication can be shut off.

Therefore, when the piston part 3 is formed as described above, during the extension stroke when the piston part 3 moves upward within the cylinder 1, the orifice 5 shown in FIG.
0, 51, and 52, the oil in the upper chamber A flows into the lower chamber B via the expansion side passage 30a and the side passage C, generating a low damping force, that is, so-called soft damping. Force is generated.

At this time, oil from the side passage C flows into the lower chamber B via the extension side ramp 30b, but in the low piston speed range, the damping force is applied by the stamped orifice 30g' of the seat portion 30g. When the piston speed is in the medium speed range, a damping force is generated due to the lowering of the leaf valve 31 adjacent to the plate valve 33, and when the piston speed is in the high speed range, a damping force is generated in the extension side ramp 30b. Therefore, there is a damping force generated due to port characteristics. In the middle and high speed ranges, the expansion valve 31 also opens and its damping force is also generated. In addition, in the low speed range of the piston, the so-called orifice characteristics are also achieved by the stamping orifice 41a' of the seat part 41a in the set nut 4 and the stamping orifice 30f' of the seat part 30f on the lower bottom surface of the piston body 30. Of course, it can be expected that the damping force will be generated.

Also, the control valve 5 is rotated to close the orifices 50, 51, 52, and the side channel C
When the oil in the upper chamber A flows into the lower chamber B through the expansion side oil passage 30a, the damping force in the low speed range of the piston is applied to the seat portion forming the opening window 30d. The plate valve 3 is generated by the stamped orifice 30f' of 30f, and descends against the spring in the medium piston speed range.
The damping force is generated by the leaf valve 31 which is energized as shown in FIG.

Next, during the pressure stroke in which the piston part 3 descends inside the cylinder 1, the oil in the lower chamber B is drained from the base valve part (not shown) disposed inside the lower end of the cylinder 1 as the piston part 3 descends. ) into a reservoir chamber (not shown), and a portion of the oil in the lower chamber B flows into the upper chamber A.

At this time, when the control valve 5 is rotated to close the orifices 50, 51, 52 and the communication between the lower chamber B and the upper chamber A via the side passage C is cut off, the pressure side of the piston body 30 The oil flowing into the oil passage 30h flows through the seat portion 30 forming the opening window 30j in the low piston speed range.
When the piston speed is in the medium speed range, the non-return valve 35 is pushed open through the stamped orifice 30l', and when the piston speed is in the high speed range, the desired damping is applied via the pressure side oil passage 30h. Power generation is expected.

Further, when the control valve 5 is rotated and the upper chamber A and the lower chamber B are brought into communication via the pressure side passage 30h and the side passage C, the leaf valve 40 in the set nut 4 is pushed up and the lower chamber B is opened.
The oil inside flows into the side passage C, and the pressure side slope 3
0i and ports 23, 24 of piston rod 2
It will flow into the upper chamber A through. At this time, the state of communication between the piston rod 2 and the control valve 5 is the same as that shown in FIG. In the low piston speed range, a damping force with orifice characteristics is generated by the orifices 50, 51 of the control valve 5 and the orifice 30m' of the opening window 30k, and in the medium piston speed range, the damping force of the non-return valve is generated. 35 generates a damping force with valve characteristics, and in the high piston speed range, the compression side slope 3
There is a damping force generated due to port characteristics due to 0i.

In the embodiment described above, the opening windows 30d, 30
e, 30j, and 30k are formed with expansion side oil passages 30i opening, respectively, but instead of this, any selected opening window 3
It may be made to open at 0d, 30e or 30j, 30k. That is, the pressure receiving area may be selected. In addition, opening windows 30d, 3
The sizes of 0e, 30j, and 30k are all formed to be the same in this embodiment, but instead of this, it is also possible to provide a difference in size, and in this case, the receiving pressure This means that the size of the area can be arbitrarily selected.

That is, the opening window 30d, 30e or 30
By forming j, 30k, during the extension stroke,
In any case during the pressure stroke, if the size of the opening window area, that is, the size of the pressure-receiving surface, becomes large, a low damping force can be expected to be generated in the medium speed range of the piston, and the size of the pressure-receiving surface increases. If it is small, high damping force can be expected to be generated in the medium piston speed range. And the extension side oil passage 30a,
By selecting whether to form the expansion side slope 30b, the compression side oil passage 30h, or the compression side slope 30i, it is possible to select even finer damping force adjustment.

Therefore, there is no need to separately form each piston body 30 with a shock absorber.
Since it is only necessary to drill selected ports, the number of parts and assembly steps are reduced.

In addition, in the above-described embodiment, the growth side ramp 30
The annular groove 30c, which opens at the upper end side of b and opens at the lower end side of the compression side ramp 30i, is formed on the piston body 30 side, but instead, as shown by the imaginary line in FIG. annular groove 3
It may also be formed as 0c′, and
It may be formed so that both grooves 30c and 30c' are provided on both sides.

5, 6, and 7A and 7B show shock absorbers according to other embodiments of the present invention. It is designed so that the damping force can be adjusted to medium.

That is, although the basic configurations of the cylinder 1, piston rod 2, piston part 3, set nut 4, and control valve 5 are the same, necessary changes have been made to the piston rod 2, piston part 3, and control valve 5. be.

First, in the piston part 3, the piston body 3
0, a second extension side slope 30b' and a second compression side slope 30i' are formed (see FIGS. 7A and 7B). Then, the spigot part 2 of the piston rod 2
5. Two upper and lower annular grooves 29a and 29b are formed on the outer peripheral surface. The spigot part 25 of the piston rod 2 also has ports 28a and 28b that open into the upper and lower annular grooves 29a and 29b.
(See FIG. 5 and FIGS. 7A and 7B).

Annular groove 2 on the upper stage side of the annular grooves 29a and 29b
9b is opened at the upper end of the second extension side ramp 30b', and the lower annular groove 29a is opened at the lower end of the second compression side ramp 30i' (see FIGS. 7A and B). . Note that the upper end side of the expansion side slope 30b opens into the lower annular groove 29a, and the lower end side of the compression side slope 30i opens into the upper annular groove 29b.

As shown in FIGS. 7A and 7B and FIG. 12, the second extension ramp 30b' communicates with the lower chamber B through the opening window 30r and the stamping orifice.

Similarly, as shown in FIGS. 7A and 7B and FIG. 11, the second compression side ramp 30i' communicates the opening window 30n with the upper chamber A through the embossing orifice.

Next, the control valve 5 communicates in the vertical direction with ports 23 and 24 that are bored in two stages, upper and lower, in the narrow diameter portion 22 of the piston rod 2, and the control valve 5 is rotated by a certain angle, for example, 60 degrees. an orifice 50a formed so as to be able to face the ports 23, 24 even when the
50b and 51a, 51b (8th
(see figure). Also, two orifices 52a, 5 are bored so as to face the lower port 28a in the spigot part 25 of the piston rod 2.
It also has 2b. The two orifices 52
a and 52b are bored so that they can selectively face the port 28a when the control valve 5 is rotated 60 degrees (see FIG. 10). It also has another orifice 52' bored so as to be able to face the port 28b on the upper stage side of the spigot part 25 (see FIG. 9).

The operation of the shock absorber as another embodiment formed as described above will be briefly explained.

First, in the so-called hard mode, as shown in FIG. 6, by rotating the control valve 5,
Communication between the orifice of the control valve 5 and the port on the piston rod 2 side is cut off. That is, in FIGS. 8, 9, and 10, the core line a
For example, 60° control valve 5 so that
by rotating from the state shown in FIG. Further, during the so-called soft operation, as shown in FIG. 7, the orifice of the control valve 5 and the port on the piston rod 2 side are all communicated with each other. That is, by rotating the control valve 5 by, for example, 60 degrees from the state shown in FIG. 5 so that the core line b becomes b' in FIGS. 8, 9, and 10. When the control valve 5 is positioned as shown in FIGS. 8, 9, and 10, the annular groove 2 is in the so-called medium position.
When there is a state shown in FIG. 5 in which communication via 9b is cut off, it is possible to generate a moderate damping force.

In addition, in this embodiment as well, the opening window 30 is provided on the upper end surface and the lower bottom surface of the piston body 30 constituting the piston portion 3, as in the case of the above-mentioned embodiment.
j, 30k (see Figures 2 and 6) and 3
0d and 30e (see FIGS. 3 and 5) are formed. In addition, each opening window 30d, 30e, 3
Sheet portions 30f, 30 forming 0j, 30k
Etching orifices 30f', 30g', 30l' and 30m' are formed in the holes g, 30l and 30m, respectively.

The damping forces generated during the extension stroke and the compression stroke are generated in the same manner as in the embodiment described above.

〔Effect of the invention〕

As described above, according to the present invention, in addition to the growth side oil passage and the compression side oil passage, an independent growth side slope and a compression side slope are provided, and by opening and closing the growth side slope and the compression side slope with the rotary valve, the growth side valve and the pressure side slope are opened and closed. Since the pressure receiving area for the non-return valve is changed, a high damping force can be generated when the growth side slope and the compression side slope are closed, and a low damping force can be generated when they are open. Furthermore, in cooperation with the rotary valve, it is possible to adjust the damping force between so-called soft and hard conditions, as well as medium mode, so the damping force can be generated according to the vehicle's driving conditions, improving driving stability. This has the advantage that it is possible to improve the ride quality as well as improve the riding comfort.

In addition, as a structure for adjusting the damping force as described above, it is sufficient to select a so-called port in the piston body, which eliminates the need for a complicated structure, reduces the number of parts, and reduces the number of assembly steps. It also has the advantage of not causing so-called high costs in manufacturing.

[Brief explanation of the drawing]

1 is a partial sectional view showing a shock absorber according to an embodiment of the present invention, FIG. 2 is a top end view of the piston body of FIG. 1, and FIG. 3 is a bottom end view of the piston body of FIG. 4 is a partial longitudinal sectional view of FIG. 1 taken from another angle, FIG. 5 is a partial longitudinal sectional view showing a shock absorber according to another embodiment of the present invention, and FIG. 6 is a partial longitudinal sectional view of the shock absorber of FIG. 7A and 7B are partial longitudinal sectional views showing the inclined passages as ports in the piston body; FIG. 8 is a partial vertical sectional view taken from an angle; FIG. 8 shows the piston rod and control valve indicated by the line in FIG. A sectional view of FIG. 9 is similar to FIG. 8 indicated by - in FIG. 5, and FIG.
The diagram is similar to Figure 8, indicated by the middle line - in Figure 5,
11 is a top end view of the piston body in FIG. 5, and FIG. 12 is a bottom end view of the piston body in FIG. 5. DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Piston rod, 3... Piston part, 4... Set nut, 5... Control valve, 23, 24, 28, 28a, 28b... Port, 29a, 29b, 30c, 30c'... Annular groove,
30...Piston body, 30a...Extension side oil path, 30
b, 30b'... Extension side slope, 30d, 30e, 30
j, 30k, 30n, 30r...opening window, 30f,
30g, 30l, 30m...seat part, 30f', 3
0g', 30l', 30m'...Emphasis orifice, 30h
...Pressure side oil passage, 30i, 30i'...Pressure side slope, 31...
Leaf valve as expansion side valve, 33... Plate valve, 34
...Spring, 35...Non-return valve as leaf valve, 40...Leaf valve as non-return valve, 50, 50a, 50b, 51, 51a, 5
1b, 52, 52', 52a, 52b...orifice, A...upper chamber, B...lower chamber, C...side channel.

Claims (1)

[Claims] 1. A piston rod is movably inserted into the cylinder via a piston, the piston body defines an upper chamber and a lower chamber in the cylinder, and the piston body communicates with the upper chamber and the lower chamber. A rebound side oil passage and a compression side oil passage are formed on the end face of the piston body, and an expansion side valve that opens and closes the expansion side oil passage and a leaf valve that opens and closes the compression side oil passage are adjacent to each other so as to be openable and closable. is provided with a side passage that communicates the upper chamber and the lower chamber, a non-return valve is provided at the bottom of this side passage for opening and closing the side passage, and a control valve is rotatably inserted into the side passage. In the shock absorber, the control valve is formed with an orifice for opening and closing the upper chamber and the side passage, and the piston body is formed with a growth side ramp independent of the expansion side passage and the compression side passage, and the expansion side slope is formed in the piston body. One end of the side slope and the compression side slope are opened to the end faces of the expansion side valve and the leaf valve, respectively, and the other end is opened and closed to the side path through a port provided in the piston rod and an orifice provided in the rotary valve. A shock absorber damping force adjustment structure. 2. A damping force adjustment structure for a shock absorber according to claim 1, wherein a plurality of rebound side slopes and a plurality of compression side slopes are provided. 3. The shock absorber according to claim 1, wherein the expansion side oil passage, the compression side oil passage, the expansion side slope, and the compression side slope are opened at the end faces of the expansion side valve and the leaf valve through independent opening windows, respectively. damping force adjustment structure.