JP2532004Y2 - Variable damping force valve - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a variable damping force valve used for a hydropneumatic suspension of an automobile, and particularly to a suspension of a large automobile such as a bus or a truck. It relates to an effective damping force variable valve.

[Conventional technology]

In recent years, hydropneumatic systems have been introduced into suspensions of automobiles. In this suspension device, a hydraulic cylinder device and an accumulator are used, high-pressure gas in the accumulator is used as a gas spring, and a damping valve is arranged between the hydraulic cylinder device and the accumulator, Alternatively, the damping valve is integrated directly into the hydraulic cylinder device.

In general, it is desirable to set the damping force of the suspension of the vehicle as low as possible from the viewpoint of riding comfort (the suspension becomes softer). However, when the vehicle travels on a road surface having a large change in a situation where the damping force is low, a large vibration occurs in the vehicle body. That is, while the vehicle is running, rolling and pitching occur, but with a low damping force, the effect of damping such shaking is small.

Therefore, as described in JP-A-62-15636, a hydropneumatic suspension device in which a damping force generating valve constituted by a variable orifice and a poppet valve is incorporated in a hydraulic cylinder device, Has been proposed.

Examples of this type of suspension device are described in Japanese Unexamined Utility Model Publication No. Sho 62-25346 and Japanese Unexamined Patent Publication No. Sho 64
JP-A-78910 and JP-A-1-98708.

[Problems to be solved by the invention]

For vehicles such as trucks and buses, the sprung mass load differs greatly between when the load is loaded and when the load is empty, so the suspension characteristics must be changed between when the load is loaded and when the load is empty. Is desirable. In other words, it is preferable that the damping force be large when loading, and be small when empty.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a load-sensitive damping force variable valve capable of obtaining a damping force corresponding to a variation in a sprung load of a vehicle. It is in.

[Means for solving the problem]

In the variable damping valve according to the present invention, an A port is connected to a cylinder device (5) interposed between a vehicle body (1) and a wheel (2), and a B port is connected to an accumulator (11). A damping force variable valve configured to change and adjust the damping force of the suspension by controlling the flow of hydraulic oil between the port and the B port; The passage (16), the second passage (17), the third passage (18), and the fourth passage (19) are connected in parallel with each other between the A port and the B port, and the first passage ( 16) is provided with a normally closed first main valve (31) that allows a flow from the B port to the A port when the internal pressure of the cylinder device (5) becomes equal to or less than a set value. In the two passages (17), the cylinder A normally-closed second main valve (41) that allows the flow from the port A to the port B when the internal pressure of the device (5) becomes equal to or higher than a set value is interposed, and is provided in the third passage (18). The first check valve (32) and the first throttle (46), which allow only the flow from the B port side to the A port side, are interposed in order from the A port side, and the fourth passage (19) A second check valve (42) and a second throttle (55) that allow only the flow from the A port side to the B port side are interposed in order from the B port side, and the first main valve ( 31) is pressed by a first piston (49) operated by the hydraulic oil pressure on the A port side of the first check valve (32) in the third passage (18) so that the opening and closing thereof is controlled. The second main valve (41) is connected to the second reverse valve in the fourth passage (19). Wherein the opening and closing is pressed by the second piston (58) to be actuated is configured to be controlled by hydraulic fluid pressure of the B port side of the valve (42).

[Action]

While the vehicle is traveling in the normal posture, the hydraulic oil reaches the cylinder device from the accumulator through the damping force variable valve while being controlled by the controller. With this working oil, in the cylinder device, the working force of the cylinder chamber is balanced with the load of the vehicle body, and the vehicle height is maintained in a predetermined suspension state. Then, the suspension device exerts a predetermined buffering action according to the road surface condition during traveling. In this case, the variable damping force valve operates as follows.

(1) Extension operation of the suspension.

When the wheel passes through the concave portion of the road surface, the piston in the cylinder device descends, so that the pressure in the cylinder chamber decreases. At this time, the hydraulic oil that has flowed into the B port of the variable damping force valve passes through the first throttle of the variable damping force valve, opens the first check valve, and flows into the cylinder chamber via the third passage.
At this time, since the hydraulic oil is throttled in the throttle, the differential pressure Δ
P is generated and damping force is generated.

And the suspension speed (the lowering speed of the piston)
Further increases, the amount of hydraulic oil increases, so the first main valve is opened. At this time, the pressing force that keeps the first main valve closed varies depending on the magnitude of the sprung load of the vehicle, and the pressing force increases when the sprung load is large and decreases when the sprung load is small. By opening the first main valve, a large amount of hydraulic oil is supplied to the cylinder chamber of the cylinder device via the first passage. At this time,
Since the opening degree of the first main valve increases as the suspension speed increases, the pressure rise after the opening of the first main valve becomes very slow, and the damping force rises slowly.

As described above, when the sprung load of the vehicle is large, the damping force is large, and when the sprung load is small, the damping force is small, and a damping force corresponding to the magnitude of the load is obtained.

(2) Suspension shortening operation.

When the wheel passes through the convex portion of the road surface, the piston in the cylinder device rises, so that the pressure in the cylinder chamber rises. At this time, the hydraulic oil flows out of the cylinder chamber via the oil passage through the damping force variable valve. In the case of this suspension shortening operation, the hydraulic oil flowing into the port A of the variable damping force valve opens the second check valve through the second throttle of the variable damping force valve, and flows into the accumulator via the fourth passage. I do.

And the suspension speed (the rising speed of the piston)
Further increases, the amount of hydraulic oil increases, so the second main valve is opened. At this time, the pressing force that keeps the second main valve closed varies according to the magnitude of the sprung load of the vehicle, and the pressing force increases when the sprung load is large and decreases when the sprung load is small. By opening the second main valve, a large amount of hydraulic oil is discharged from the cylinder chamber of the cylinder device through the second passage. And
As the degree of opening increases as the suspension speed increases,
The pressure rise after the opening of the second main valve becomes very slow, and the damping force rises slowly. As described above, when the sprung load of the vehicle is large, the damping force is large, and when the sprung load is small, the damping force is small, and a damping force corresponding to the magnitude of the load is obtained.

〔Example〕

FIG. 1 is a circuit diagram showing a suspension device using a variable damping force valve according to an embodiment of the present invention.
The figure is a diagram for explaining the operation, and FIG. 3 is a longitudinal sectional view showing the damping force variable valve.

In this embodiment, the variable damping force valve according to the present invention is incorporated in a hydropneumatic suspension device. The suspension device 4 includes a hydraulic cylinder device (hereinafter, simply referred to as a cylinder device) 5. The cylinder device 5 is mounted on a vehicle body 1 of a large vehicle such as a truck or a bus so as to suspend the wheels 2. . That is, the main body 6 of the cylinder device 5 is rotatably supported by the vehicle body 1, and the rod 9 of the piston 8 is rotatably supported by the wheel 2. An oil passage 10 is connected to the cylinder chamber 7 of the main body 6 on the side opposite to the piston 8.
Is connected to a hydraulic source 12 via an accumulator 11. A variable damping force valve 13 is provided in the oil passage 10 with the cylinder device 5.
And the accumulator 11.

The damping force variable valve 13 is a first passage that communicates a port (hereinafter, referred to as an A port) connected to the cylinder device 5 and a port (hereinafter, referred to as a B port) connected to the accumulator 11. 16, the second passage 17,
A third passage 18 and a fourth passage 19 are provided. The first valve device 21 is configured to control the flow from the B port to the A port when the internal pressure of the cylinder device 5 falls below a set value. The second valve device 22 is configured to control the flow from the port A to the port B when the internal pressure of the cylinder device 5 exceeds a set value.

 Next, a specific structure of the damping force variable valve 13 will be described.

The variable damping force valve 13 includes a body 23 having a hollow portion 24 formed therein. An A port is connected to one end closed wall of the body 23 and a B port is connected to the hollow portion 24 at the other end closed wall. It is established in. A partition wall 20 is provided at an intermediate portion of the hollow portion 24 of the body 23 so as to partition the hollow portion 24 into two portions in a direction perpendicular to the axis. A first valve chamber 27 is provided on one side of the partition wall 20. However, a second valve chamber 35 is formed on the other side, respectively. The first valve chamber 27 and the second valve chamber 35 communicate with each other on the A port side and the B port side, and are connected to the A port and the B port, respectively. And the first
The valve chamber 27 is provided with a first valve device 21, and the second valve room 35 is provided with a second valve device 22.

The first valve device 21 will be described. A first valve plate 26 is disposed and fixed between the partition wall 20 and the body 23 so as to partition the inside of the first valve chamber 27 into the A port side and the B port side. ing. A first valve guide 25 formed in a cylindrical shape with an open end protrudes in the axial direction at the center of the first valve plate 26 on the A port side. Around the guide 25, a plurality of valve ports 28 are arranged concentrically and are opened so as to penetrate in the axial direction. On the outer periphery of the first valve guide 25, a first main valve 31 formed in a cylindrical shape with a bottom is slidably fitted in the axial direction. First, the seat 29 surrounds the valve port 28.
It protrudes from the valve plate 26. 1st main valve
A plurality of communication paths 30 are formed concentrically at the bottom of 31.

In the first valve guide 25, a first check valve 32 that allows only the flow from the B port side to the A port side is mounted. That is, the check valve 32 includes a cylindrical portion 33a which is slidably fitted in the valve guide 25 in the axial direction, and a valve head protruding by closing an opening at an end of the cylindrical portion 33a on the valve plate 26 side. A valve portion 33b having a portion, and a spring 34 mounted between the inner surface of the valve portion 33b and the bottom surface of the first main valve 31.
The valve portion 33b urged toward the valve plate 26 closes the valve port 45 provided on the valve plate 26. The valve port 45 is opened halfway in the axial direction from the end face of the first valve plate 26 on the check valve 32 side, and is opened halfway in the axial direction from the end face of the valve plate 26 on the B port side. The first orifice 46 communicates with the first orifice 46. The first orifice 46 serving as the first throttle is set to have a small diameter with a larger throttle amount than the second orifice 55 serving as the two throttles described later. The valve portion 33b of the check valve 32 is provided with a plurality of communication passages 47 penetrating into the cylindrical portion 33a.

Next, the body 23 is provided with a first load sensitive chamber 48 in a thick portion provided at the end on the A port side, and a first piston 49 is slidably fitted in the first load sensitive chamber 48. Has been inserted.
The first piston 49 is integrally provided with a first piston rod 50, which penetrates the body 23 slidably in the axial direction and extends to the bottom side of the first main valve 31. Has been established. The head side of the piston 49 of the first load-responsive chamber 48 communicates with the first valve chamber 27 through an oil passage 51 opened in the body 23, and the opposite side of the head to the body 23.
The air is opened to the atmosphere via an air breather 53 attached to the outer surface of the body 23 by an air passage 52 established in the air conditioner. Therefore, at the time of suspension operation, the piston 49 is pressed by the hydraulic pressure corresponding to the sprung load of the vehicle, and the first main valve 31 is pressed against the valve seat 29 by the piston rod 50, whereby the valve port 28 is closed. It is in a state of being left. Since the pressing force at this time, that is, the hydraulic pressure, varies depending on the sprung load of the vehicle, the pressing force is large when loading and the pressing force is small when empty.

The first valve device 21 configured as described above,
Load sensitive chamber 48, first piston 49, first piston rod 5
The same components as the first oil passage 51, the first air passage 52, and the first air breather 53 are provided on the second valve chamber 35 side in a rotationally symmetric manner with these. That is, the second valve device 22
(The second valve plate 36, the second valve port 37, the second valve guide 38, the second valve seat 39, the second main valve 41, the second check valve 4
2, the cylindrical portion 43a, the valve portion 43b, the spring 44, the communication passage 40, the valve port 54, the second orifice 55, the communication passage 56), the second load sensitive chamber 57, the second piston 58, the second piston rod 59, A second oil passage 60, a second air passage 61, and a second air breather 62 are provided.

 Next, the operation will be described.

While the vehicle is running in a normal posture, the hydraulic oil is controlled by a controller (not shown), and the hydraulic oil is supplied from the hydraulic source 12 to the oil passage
10 → Accumulator 11 → Oil passage 10 → Variable damping force valve 13
→ It reaches the cylinder device 5 via the oil passage 10. With this hydraulic oil, in the cylinder device 5, the acting force of the cylinder chamber 7 is balanced with the load of the vehicle body 1, and the vehicle height is maintained in a predetermined suspension state.

Then, the suspension device 4 exerts a predetermined damping action according to the road surface condition during traveling. In this case, the damping force variable valve 13 operates as follows.

(1) Extension operation of the suspension.

In FIG. 1, when the wheel 2 passes through the concave portion 3a of the road surface 3, the piston 8 in the cylinder device 5 descends, so that the pressure in the cylinder chamber 7 decreases. At this time, the hydraulic oil is supplied from the oil passage 10 through the damping force variable valve 13 to the cylinder chamber 7.
Flows into.

In this case, the hydraulic oil flowing into the B port of the damping force variable valve 13 flows from the third passage 18, ie, the B port side of the first valve chamber 27, through the first orifice 46, the valve port 45, and the check valve 32. Through the communication passage 47 of the valve portion 33b of the check valve 32 and the communication passage 30 of the first main valve 31 to enter the A port side of the first valve chamber 27, and reach the cylinder chamber 7 via the A port. . Since the hydraulic oil is throttled at the first orifice 46, the differential pressure ΔP
Is generated, and a predetermined damping force is generated.

When the suspension speed (the lowering speed of the piston 8) further increases, the amount of hydraulic oil increases, so that the pressure on the B port side of the first valve chamber 27 increases, and finally the first main valve 31 is opened. Is ventured. This first main valve
By opening the valve 31, a large amount of hydraulic oil is supplied to the cylinder chamber 7 of the cylinder device 5 via the first passage 16.

At this time, the first main valve 31 opens against the pressing force of the piston 49 fitted in the load sensitive chamber 48. At this time, the pressing force of the piston 49 is large when loading, and small when empty. Since the opening degree of the first main valve 31 increases with an increase in the suspension speed, the first main valve 31
The pressure rise on the B port side of the first valve chamber 27 after opening is very slow.

Here, in FIG. 2, a straight line oa indicates the suspension characteristics of the first orifice 46 during the extension operation, and indicates a state in which the damping force sharply increases. Also, the straight line ab
Indicates suspension characteristics due to the operation of the first main valve 31, and indicates a state where the damping force is slowly increasing.

In FIG. 2, the polygonal line oab shows the suspension characteristics when loading, and the polygonal line oa'-b 'shows the suspension characteristics when empty.

(2) Suspension shortening operation.

By the way, it is required to change the damping force between the suspension operation and the extension operation of the suspension for the following reasons.

First, when passing through the concave portion 3 a of the road surface 3, it is desired that the piston rod 9 be less likely to move toward the extension side so as to avoid the adverse effect of the push-up. That is, the larger the damping force, the better.

On the other hand, when riding on the convex portion 3b of the road surface 3 during traveling, it is desirable that the piston rod 9 be quickly moved to the contraction side to effectively absorb the impact. That is, the smaller the damping force, the better. In other words, it is desirable to control the flow rate of the hydraulic oil during the shortening operation of the suspension so as to be larger than that during the extending operation.

Therefore, in the present embodiment, the diameter of the second orifice 55 is made larger than the diameter of the first orifice 46 and the amount of throttle is reduced, so that the flow rate during the shortening operation of the suspension is as described in the above (1). It is controlled so that it becomes larger than that during the extension operation.

In FIG. 1, when the wheel 2 passes through the convex portion 3b of the road surface 3, the piston 8 in the cylinder device 5 rises, so that the pressure in the cylinder chamber 7 rises. At this time, the hydraulic oil is supplied from the oil passage 10 through the damping force variable valve 13 to the cylinder chamber 7.
Spill out of. In the case of this suspension shortening operation, the hydraulic oil flowing into the A port of the variable damping force valve 13
The passage 19 leads to the accumulator 11.

That is, in the fourth passage 19, the operating oil opens the check valve 42 from the port A side of the second valve chamber 35 through the second orifice 55 and the valve port 54, and the valve oil 43 b of the check valve 42 Through the communication passage 56 and the communication passage 40 of the second main valve 41, the B of the second valve chamber 35
It enters the port side and reaches the accumulator 11 via the B port. Then, since the hydraulic oil is throttled at the second orifice 55, a differential pressure ΔP is generated, and a damping force is generated. At this time, since the diameter of the second orifice 55 is set to be large, the flow amount increases, and the attenuation amount is suppressed to a small value.

When the suspension speed (the rising speed of the piston 8) further increases, the amount of hydraulic oil increases, so that the pressure on the A port side of the second valve chamber 35 increases, and finally the second main valve 41 opens. Is ventured. This second main valve
By opening the valve 41, a large amount of hydraulic oil is discharged from the cylinder chamber 7 of the cylinder device 5 through the second passage 17.

At this time, the second main valve 41 opens against the pressing force of the piston 58 of the second load sensitive chamber 57. At this time, the pressing force of the piston 58 is large when loading, and small when empty. Since the degree of opening of the second main valve 41 increases as the suspension speed increases, the pressure increase on the A port side of the second valve chamber 35 after the opening of the second main valve 41 is very slow.

Here, in FIG. 2, a straight line oc indicates the suspension characteristics of the second orifice 55 during the suspension shortening operation, and indicates a state in which the damping force sharply increases.
Further, a straight line cd indicates the suspension characteristic due to the operation of the second main valve 41, and indicates a state where the damping force is slowly rising.

In FIG. 2, a broken line ocd shows suspension characteristics when loading, and a broken line oc'-d 'shows suspension characteristics when unloaded.

The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the scope of the invention.

For example, the fixed aperture is not limited to the orifice, and a chalk or the like can be used.

[Effect of the invention]

As described above, according to the damping force variable valve of the present invention, a damping force corresponding to the fluctuation of the sprung load of the vehicle can be obtained. Suspension characteristics can be realized.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a suspension device using a variable damping force valve according to an embodiment of the present invention, FIG. 2 is a diagram for explaining the operation thereof, and FIG. It is a longitudinal section showing a valve. DESCRIPTION OF SYMBOLS 1 ... Body, 2 ... Wheel, 3 ... Road surface, 3a ... Concave part, 3b ... Convex part,
4 ... Suspension device, 5 ... Hydraulic cylinder device, 6 ...
Body, 7: Cylinder chamber, 8: Piston, 9: Rod, 10
... oil passage, 11 ... accumulator, 12 ... hydraulic pressure source, 13 ... variable damping force valve, 16-19 ... first to fourth passage, 20 ... partition wall,
21 ... first valve device, 22 ... second valve device, 23 ... body, 24 ... hollow portion, 25 ... first valve guide, 26 ... first valve plate, 27 ... first valve chamber, 28 ... first valve port 29, first valve seat, 30 communication path, 31 first main valve, 32 first check valve, 33a cylindrical portion, 33b valve portion, 34 spring, 35 second valve chamber, 36 … Second valve plate, 37… second valve port, 38…
2nd valve guide, 39 ... 2nd valve seat, 40 ... communication path, 41 ... 2nd main valve, 42 ... 2nd check valve, 43a ... cylindrical part, 43b ...
Valve part, 44 ... Spring, 45 ... Valve, 46 ... First orifice (first throttle), 47 ... Communication path, 48 ... First load-sensitive chamber, 49 ...
1st piston, 50 ... 1st piston rod, 51 ... 1st oil path, 52 ... 1st air path, 53 ... 1st air breather, 54 ... valve port, 55 ... 2nd orifice (2nd throttle), 56 ... Communication passage, 57
.., A second load-responsive chamber, 58... A second piston, 59... A second piston rod, 60.

Claims (1)

(57) [Scope of request for utility model registration] An A port is connected to a cylinder device (5) interposed between a vehicle body (1) and a wheel (2), and a B port is connected to an accumulator (11). By controlling the flow of hydraulic oil between
A damping force variable valve configured to change and adjust a damping force of a suspension, wherein a first passage (16), a second passage (17), and a third passage (18) for connecting the A port and the B port respectively. ) And a fourth passage (19) are connected in parallel with each other between the A port and the B port, and the internal pressure of the cylinder device (5) in the first passage (16) is equal to or less than a set value. A normally closed first main valve (31) is provided to allow the flow from port B to port A when the internal pressure of the cylinder device (5) is set in the second passage (17). A normally closed second main valve (41) is provided to allow the flow from the port A to the port B when the pressure exceeds the value, and the third passage (18) is connected from the port B side to the port A side. Check valve (32) allowing only flow to A second check valve (42) that allows only the flow from the A port side to the B port side in the fourth passage (19); Two throttles (55) are interposed in order from the B port side, and the first main valve (31) operates on the A port side of the first check valve (32) in the third passage (18). The first main body (41) is configured to be pressed by a first piston (49) operated by hydraulic pressure to control the opening and closing thereof, and the second main valve (41) is connected to the second reverse valve in the fourth passage (19). A damping force variable valve which is configured to be pressed by a second piston (58) operated by a hydraulic oil pressure on a B port side of a stop valve (42) to control opening and closing thereof.