JP3066994B2 - Damping force adjustable shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping force adjustable shock absorber for improving the vibration characteristics of a vehicle.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, in a damping force adjusting type shock absorber, a piston a installed below a piston rod f in a cylinder k is provided with a pressure side valve c on an upper chamber b side. At the same time, the extension valve e
And a rotary valve g having a small hole formed in the center of the piston rod f in a direction perpendicular to the axis.

The rotary valve g is rotated so that the piston upper and lower chambers b and d communicate with each other through the hole of the piston rod f.

The rotary valve g is joined to a control rod h extending from the center of the piston rod f to the upper end of the rod. When the rotary chopper i at the upper end of the piston rod f rotates, the small hole of the rotary valve g is opened. Open and close.

[0005] a) When the small hole of the rotary valve g is closed, the oil j of the piston upper and lower chambers b and d is attenuated by the extension side valve e and the compression side valve c, respectively, as the piston rod f moves up and down. It reciprocates between the upper and lower chambers b and d while generating a force. Accordingly, the damping force at this time is high because the entire flow rate is increased and flows through the pressure side valves e and c.

B) When the small hole of the rotary valve g is open, the flow flowing through the small hole of the rotary valve g can be parallel to the flow flowing through the expansion valve e. Therefore, the flow between the upper and lower chambers b and d is diverted, resulting in a low damping force.

[0007]

However, in the prior art, the characteristics of the small hole of the rotary valve are characteristics that are proportional to the square of the flow rate (piston speed). Also, the eyelet is placed in parallel with the valve. Therefore, A. There is a problem that in a region where the piston speed is low, even if the damping force is changed by opening and closing the rotary valve, there is not much change in a region where the piston speed is high.

B. If the variation width of the damping force is to be increased, there is a problem that only a characteristic having almost no damping force can be obtained in a region where the piston speed is low.

C. The above A. Due to the restriction of B, there is a problem that an ideal damping force characteristic aiming at a balance between ride comfort and operability originally required of the vehicle cannot be obtained, and a compromise is made within a variable range.

D. Since the size of the small hole is selected by rotating a relatively small-diameter rotary valve installed in the piston rod, the number of switching of the damping force is limited to about two to three steps.

E. For the above reasons, in order to obtain the optimal damping force according to the running condition of the vehicle and improve the vibration damping performance, it is not sufficient in terms of the fineness of the variable width as well as the restriction during switching. There is a problem that there is.

In view of the above, the present invention has been made in view of the above-mentioned problems of the prior art, and generates a high damping force in order to suppress a change in the attitude of a vehicle, and also responds to various road surface conditions and running conditions. It is another object of the present invention to provide a damping force-adjustable shock absorber capable of finely switching the damping force, increasing the switching width, and improving the vibration characteristics of the vehicle.

[0013]

In order to achieve the above-mentioned object, a means of the present invention is that a piston rod is movably inserted into a cylinder via a piston, and the piston has an upper chamber and a lower chamber in the cylinder. The piston is provided with an extension-side check valve that opens during the pressure stroke and communicates the upper chamber and the lower chamber, and a base valve is provided below the lower chamber. A pressure check valve that communicates with the reservoir chamber is provided, and in the one-weft shock absorber in which oil in the upper chamber and the lower chamber flows out to the reservoir chamber via the common compression damping valve during the expansion stroke and the compression stroke, The common damping valve includes a movable valve body, a first leaf valve provided at one end of the valve body, a second leaf valve provided at the other end of the valve body, a communication hole passing through the valve body, and a communication port. The hole provided in the middle of the hole A first leaf valve configured as a valve for generating a centering spring and a damping force of the valve body, and a second leaf valve configured as a valve body for generating a damping force. And a spring member for imparting initial deflection to the centering spring and the first leaf valve, wherein the first leaf valve partitions a primary chamber communicating with the upper chamber and a downstream chamber communicating with the reservoir chamber. 2 leaf valve divides the secondary room on the back,
The primary chamber and the secondary chamber communicate with each other through a communication hole in the valve body and the orifice. Further, the secondary chamber is opened and closed to the reservoir chamber side via a poppet valve, and the first chamber is opened and closed by opening and closing the poppet valve. The cracking pressure of the leaf valve is adjusted.

Second, a solenoid valve is used as means for changing or opening and closing the seat force of the poppet valve.

Third, the second solenoid valve uses a proportional solenoid.

Fourth, means for changing the seat force of the poppet valve uses hydraulic pressure or pneumatic pressure.

[0017]

The operation will be described below using reference numerals. (1) Extension stroke Since the oil in the upper piston chamber 3 is stopped by the extension-side check valve 2, the oil does not flow to the lower piston chamber 5, but the upper communication hole 1.
1 flows out to the communication room 12.

At this time, in the piston lower chamber 5, the communication chamber 12
Although the oil that has flowed out is insufficient, the pressure side check valve 6 is pushed open without difficulty, and oil is freely supplied from the reservoir chamber 20. (2) Pressure stroke When the piston rod 7 enters the cylinder 8, the flow of oil is stopped at the base valve 4 by the action of the pressure side check valve 6, so that the piston lower chamber 5
Oil pushes open the extension side check valve 2 and smoothly enters the upper piston chamber 3.

At this time, since the volume of the piston upper and lower chambers 3 and 5 is larger than the volume of the piston lower chamber 5 by the volume of the piston rod 7, the surplus volume flows into the communication chamber 12 through the upper communication hole 11. (3) Operation of the Compression Damping Valve 15 The oil that has flowed into the communication chamber 12 on the shock absorber A side through the holes 13 and 14 from the lower portion of the shock absorber A main body during both the expansion stroke and the compression stroke. Common damping valve 15
Acting on the primary pressure chamber 16. At the same time, it acts on the secondary pressure chamber 22 via the orifice 21 in the valve body 23 and the communication hole 28.

1) When the poppet valve 24 is closed, there is no oil flow between the primary pressure chamber 16 and the secondary pressure chamber 22, and the two chambers 1
The same pressure acts on 6, 22. At this time, the valve body 23 does not move due to the balance of the force due to the pressure of the two chambers 16 and 22.

The oil that has flowed up to the primary pressure chamber 16 pushes open the outer periphery of the leaf valve 17 and returns to the reserve chamber 20 via the downstream chamber 33 and the holes 18 and 19 while generating a damping force.

At this time, since the same pressure acts on the secondary pressure chamber 22, if the rigidity of the leaf valve 30 is also the same or smaller than that of the leaf valve 17, the outer periphery separates from the valve seat 32 and opens. And

Opening temporarily, the primary pressure chamber 16 and the secondary pressure chamber 22
When a flow occurs between the pressures, the pressure in the secondary pressure chamber 22 drops below the pressure in the primary pressure chamber 16 due to the resistance of the orifice 21, and
Because of the resistance of the orifice 35, the back pressure of the downstream chamber 34 increases, so that even if it opens, it closes instantly.

The cracking pressure of the leaf valve 17 in the primary pressure chamber 16 is high because it gives the leaf valve 17 an initial deflection. Therefore, a high damping force is generated.

2) When the poppet valve 24 is open, there is a flow through the orifice 21 from the primary pressure chamber 16 to the secondary pressure chamber 22, and due to the resistance of the orifice 21, the secondary pressure chamber 22
Is lower than the primary pressure chamber 16.

At this time, the balance of the force acting on the valve body 23 is lost due to the pressure difference between the two chambers 16 and 22, and the valve body 23 moves to the secondary pressure chamber 22 side.

The valve element 23 moves until the force by the pressure applied from both chambers 16 and 22 and the spring force generated by the deflection of the leaf valves 17 and 30 are balanced.

When the valve element 23 moves toward the secondary pressure chamber 22, the initial deflection amount of the leaf valve 17 pressed against the valve seat 31 decreases, and the pressing force decreases. That is, the leaf valve 1 against the flow of oil from the communication chamber 12
7, the cracking pressure is reduced, and a low damping force can be obtained.

The movement of the valve body 23 causes the downstream chambers 33, 3
Since the orifice 35 acts as a resistance to the flow of oil reciprocating in 4, vibration of the valve body 23 can be suppressed.

3) Operation and damping force of the poppet valve 24 The solenoid 37 shown in FIG. 1 is of a push type.
When energized, the push pin 38 is moved to the poppet valve 24 side. The spring 36 is set such that the poppet valve 24 has a slight pressing force and seats even when the solenoid 37 is not energized.

The poppet valve 24 is pressed by a spring 36 and a push pin 38 of a solenoid 37. When a current is applied to the solenoid 37, a suction force is generated to press the poppet valve 24. Power increases.

When the solenoid 37 is the proportional solenoid 27, the seat force of the poppet valve 24 can be electrically controlled because the suction force can be changed by the applied current.

The pressure in the secondary pressure chamber 22 acts in a direction to push and open the poppet valve 24. When this pressure exceeds the above-mentioned seat force, the poppet valve 24 opens. At this time, since the pressing force of the leaf valve 17 is sufficiently high, the leaf valve 17 does not open at the pressure at which the poppet valve 24 opens.

The oil that flows by pushing the poppet valve 24 open is
It returns to the reservoir chamber 20 through the holes 25, 25a and 19.

When this flow is generated, as described in the above 2), a differential pressure is generated between the primary pressure chamber 16 and the secondary pressure chamber 22, and the leaf valve 17 cracks at a low pressure, and a low damping force is generated. Is obtained. Accordingly, a damping force characteristic as shown in FIG. 2 is obtained depending on the magnitude of the current applied to the solenoid.

When the current is maximized, the poppet valve 24
Is sufficiently high, the leaf valve 17 opens first, and the high damping force described in the above 1) is obtained.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the shock absorber according to the present invention, as shown in FIG. 1, a piston rod 7 is movably inserted into a cylinder 8 via a piston 1, and the piston 1 connects the upper chamber 3 and the lower chamber 5 in the cylinder 8. The piston 1 is provided with an extension-side check valve 2 which is open during the pressure stroke and communicates the upper chamber 3 and the pressure chamber 5, and a base valve 4 is provided below the lower chamber 5. A pressure-side check valve 6 that opens during the stroke to communicate the lower chamber 5 with the reservoir chamber 20
This is a one-way flow shock absorber in which the oil in the upper chamber 3 and the lower chamber 5 flows out to the reservoir chamber 20 via the common damping valve 15 for expansion during the expansion stroke and the compression stroke. As shown in FIG. 2, the compression-extended damping valve 15 according to the present invention includes a movable valve element 23, a first leaf valve 17 provided at one end of the valve element 23, and The second provided
Leaf valve 30 and communication hole 28 penetrating valve body 23
And an orifice 21 provided in the middle of the communication hole 28, and a poppet valve 24 provided facing the valve element 23.
Further, the first leaf valve 17 is configured as a centering spring of the valve body 23 and a valve for generating a damping force.
The second leaf valve 30 is configured as a centering spring of the valve body 23 and a spring member for imparting initial deflection to the first leaf valve 17. The first leaf valve 17 is connected to the primary chamber 16 and the reservoir chamber 2 communicating with the upper chamber 3 side.
The second leaf valve 30 partitions the secondary chamber 22 at the back, and the primary chamber 16 and the secondary chamber 22 communicate with the communication hole 28 in the valve body 23. The secondary chamber 22 communicates with the orifice 21, and the secondary chamber 22 is opened and closed toward the reservoir chamber 20 via a poppet valve 24. The cracking pressure of the first leaf valve 17 is adjusted by opening and closing the poppet valve 24. Things. The details will be described below.

First, the damping force-adjustable shock absorber of the present invention has a structure in which a compression-extended damping valve 15 is integrally attached to a shock absorber A.

The shock absorber A includes a cylinder 8
The piston rod 7 is disposed in the
There is no valve for generating a damping force in the piston 1 installed at the lower part of the piston, and the extension side check valve 2 is installed at the piston upper chamber 3 side.
Is provided with a pressure-side check valve 6 on the piston lower chamber 5 side.

The upper end of the cylinder 8 is provided with a communication hole 11.
And an inner shell 9 provided on the outer periphery of the cylinder 8.
A communication chamber 12 communicating with the lower part is formed between them.

In the lower part of the communication chamber 12, holes 13 and 19 are provided.
The hole 13 communicates with the primary pressure chamber 16 through the hole 14 of the common compression damping valve 15, and the hole 19 also has the hole 1 through the leaf valve 17 of the common compression damping valve 15.
8 and is further configured to return to the reservoir chamber 20.

Further, an outer shell 10 is provided on the outer periphery of the inner shell 9, and a reserve chamber 20 serving as an oil chamber is formed between the inner shell 9 and the outer shell 10. A hole 26 communicating with the valve 4 is formed.

The compression-extension damping valve 15 is provided with a hole 14 communicating with the hole 13, and a primary pressure chamber 16 is provided at the tip of the hole 14.
And a secondary pressure chamber 22 is provided above the primary pressure chamber 16 via a valve body 23.

The hole 19 returns to the reservoir chamber 20 via the poppet valve 24 and the holes 25 and 25a.

The valve body 23 is provided with a communication hole 28 in the center axis direction, and an orifice 21 communicating with the communication hole 28 is formed at the lower end. The valve body 23 is centered by a guide 29 having an orifice 35. The guide 29
The inner circumference is supported by the leaf valve 17 on the primary pressure chamber 16 side and the leaf valve 30 on the secondary pressure chamber 22 side.

The outer circumferences of the leaf valves 17 and 30 in the primary pressure chamber 16 and the secondary pressure chamber 22 are seated with valve seats 31 and 32, respectively. Furthermore, leaf valve 1
As shown in FIG. 2, the sheets 7 and 30 give an initial deflection so that the inner peripheral side is convex.

The downstream chamber 3 of the leaf valves 17 and 30
3, 34 communicate with the orifice 35 of the guide 29.

The poppet valve 24 is held down by a spring 36 and a push pin 38 of a solenoid 37.

FIG. 4 shows a second embodiment. This second embodiment is constituted by a pull-type solenoid type, and the structure and operation of the shock absorber A and the compression / compression damping valve 15 are the same as those of the first embodiment. It has the same configuration as the example.

The spring 39 presses the poppet valve 42 to the seat through the plunger 40 and the push pin 41.

The spring force of the spring 39 is set sufficiently large so that the pressure at which the poppet valve 42 opens is higher than the pressure at which the leaf valve 17 opens.

When power is not supplied to the solenoid 37, the load of the spring 39 acts on the poppet valve 42, and the poppet valve 4
2 does not open. Therefore, a high damping force can be obtained.

When the solenoid 37 is energized,
A suction force is generated in a direction in which the plunger 40 is pulled by the core 43.

At this time, the suction force is not strong enough to overcome the force of the spring 39 and attract the plunger 40.
Poppet valve 42 remains seated.

Since the direction acts in a direction to reduce the spring force of the spring 39 acting on the poppet valve 42, the seat force of the poppet valve 42 decreases. Therefore, the poppet valve 42
Open at a pressure lower than that of the leaf valve 17, so that a low damping force can be obtained.

FIG. 5 shows a third embodiment.
While the second embodiment uses a solenoid valve, this embodiment is formed as a pressure switching type using a pneumatic or hydraulic pressure signal.

The structure and operation of the shock absorber A and the compression-extended damping force valve 15 in the third embodiment are the same as those in the first embodiment.

The poppet valve 44 is pressed by a spring 47 via a puncturing pin 45 and a piston 46. When the pressure P is not applied, the poppet valve 44
Is only the load of the spring 47, and when the pressure P is applied, the seat force increases in accordance with the magnitude of the pressure P.

Therefore, it is possible to switch from a low damping force to a high damping force depending on the magnitude of the pressure.

[0060]

Since the present invention is configured as described above, the following effects can be obtained.

A. By controlling the opening and closing of the poppet valve and changing the initial deflection of the leaf valve, which is the first leaf valve, to change the cracking pressure of the leater valve, the damping force is uniformly reduced from a low piston speed range to a high piston speed range. Can be changed, and the range of change can be widened. The first leaf valve also functions as a centering spring of the valve body and a valve for generating a damping force, and there is no need to separately use a centering spring, so that the structure is simplified and the assembling property is improved.

B. Depending on the seat force change of the poppet valve,
Since the initial deflection of the leaf valve changes, the damping force can be continuously changed over a wide range if the seat force of the poppet valve is finely controlled by a solenoid, hydraulic pressure, or pneumatic pressure.

C. Due to the method of changing the cracking pressure of the leaf valve, the change in the damping force with respect to the piston speed is close to the proportional characteristic, and there is little sudden change in the characteristic. Therefore, since the characteristics are not nonlinear, the controllability is good.

D. From the above points, an optimal damping force can be obtained according to the running condition and the vibration condition of the vehicle, and the damping performance of the vehicle is improved. In addition, ride comfort and operability can be harmonized at a high level.

[Brief description of the drawings]

FIG. 1 is a sectional view of a damping force-adjustable shock absorber according to the present invention.

FIG. 2 is a detailed view of a compression-extended damping valve of the present invention.

FIG. 3 is a damping force characteristic diagram of the present invention.

FIG. 4 is a sectional view of a main part of a pull type solenoid type according to a second embodiment.

FIG. 5 is a sectional view of a main part of a pressure switching type according to a third embodiment.

FIG. 6 is a partially cutaway sectional view of a conventional damping force-adjustable shock absorber.

[Description of Signs] 1 piston 2 extension side check valve 3 upper piston chamber 4 base valve 5 piston lower chamber 6 pressure side check valve 7 piston rod 8 cylinder 9 thinner shell 10 outer shell 11 communication hole 12 communication chamber 13 hole 14 hole 15 extension Common pressure damping valve 16 Primary pressure chamber 17 Leaf valve 18 hole 19 hole 20 Reservoir chamber (oil chamber) 21 Orifice 22 Secondary pressure chamber 23 Valve body 24 Poppet valve 25 Hole 25a Hole 26 Hole 27 Proportional solenoid 28 Communication hole 29 Guide 30 Leaf valve 31 Valve seat 32 Valve seat 33 Downstream chamber 34 Downstream chamber 35 Orifice 36 Spring 37 Solenoid 38 Pushpin 39 Spring 40 Plunger 41 Pushpin 42 Poppet valve 43 Core 44 Poppet valve 45 Push Pin 46 piston 47 spring

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16F 9/00-9/58 B60G 17/08

Claims (1)

(57) [Claims] 1. A piston rod is movably inserted into a cylinder via a piston. The piston defines an upper chamber and a lower chamber in the cylinder, and the piston is opened during a pressure stroke to form an upper chamber and a lower chamber. A base valve is provided below the lower chamber, and a pressure-side check valve is provided in the base valve that opens during the expansion stroke and communicates the lower chamber to the reservoir chamber. In a one-way flow shock absorber in which the oil in the upper chamber and the lower chamber flows out to the reservoir chamber via the common compression damping valve, the common compression damping valve is provided at a movable valve element and at one end of the valve element. A first leaf valve, a second leaf valve provided at the other end of the valve body, a communication hole penetrating the valve body, an orifice provided in the middle of the communication hole, and provided facing the valve body. Having a poppet valve and the above The first leaf valve is configured as a centering spring of the valve body and a valve for generating a damping force, and the second leaf valve is configured as a spring member for imparting initial deflection to the centering spring of the valve body and the first leaf valve. The first leaf valve defines a primary chamber communicating with the upper chamber and a downstream chamber communicating with the reservoir chamber, and the second leaf valve defines a secondary chamber at the back, and the primary chamber and the secondary chamber are separated from each other. The second chamber is opened and closed to the reservoir chamber via a poppet valve, and the cracking pressure of the first leaf valve is opened and closed by opening and closing the poppet valve. A damping force-adjustable shock absorber characterized in that the pressure is adjusted.