JP2788134B2 - Hydraulic control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hydraulic control device of the type mentioned in the general section of claim 1.

[0002]

2. Description of the Related Art An oscillating load transfer system is, for example, a crane, in which oscillating movements due to a large leverage occur at the beginning and end of a rapid load transfer. However, the oscillating motion can cause a reaction to one or more fluid-using devices, resulting in pressure fluctuations in the hydraulic system. Hydraulic columns of a theoretically incompressible medium exhibit elastic recoil during actual operation, so that due to the combined effect of various factors, oscillating movements and pressure fluctuations are disadvantageously long-term, i.e. It is held even during the movement of.

[0003] The oscillating tendency of a fluid-using device in a hydraulic circuit having at least one set of releasable load-bearing valves,
It is well known that load-bearing valves are controlled by an adjustable motion damping restrictor in the pilot line (Heilmeier & Weinlei).
n) It is true that it was published by Shokai in June 1986, D7100, page 2), but the effect provided by the motion damping diaphragm alone is often not sufficient.

[0004]

SUMMARY OF THE INVENTION The present invention is based on the problem of providing a hydraulic control device as disclosed, whereby the effective damping of pressure fluctuations is achieved in a simple and cost-effective manner. .

[0005] According to the invention, the problem raised is solved by the features disclosed in the characterizing section of claim 1.

[0006] Only the control pressure circuit of the load-bearing valve acts to damp the pressure fluctuations, but the damping takes effect in and into the actuation circuit and the liquid use equipment.
The desired damping is achieved irrespective of the type of control valve used and independently of the structural design of said control valve,
This means that any control valve can be selected. While it is possible to use complex control valves with feed flow regulators and load pressure sensing, the use of this type of control valve in systems that tend to swing may result in pressure fluctuations. It is in principle dangerous. This damping effect is probably due to the fact that the amount of hydraulic medium discharged from the pilot line via the bypass line cuts off the peaks and valleys that occur in the pressure curve in the case of pressure fluctuations. Here, the behavior of the oscillating pressure in the main line and in the liquid application device is impeded in such a way that the pressure oscillations decay rapidly. The amount of hydraulic medium discharged from the pilot line for damping purposes is small.

In the case of forklift trucks, it is well known that the lift cylinder is fixed by means of a descent brake, which limits the maximum descent speed independently of the load. The main passage of the descending brake includes an unrestricted bypass passage, which facilitates overall control characteristics with respect to suppressing pressure fluctuations.
However, this principle is not suitable for use in a crane equipped with a double-acting liquid application device.

[0008] In the case of the second embodiment, the block containing the cargo support valve remains conventional. that is,
From a production technology standpoint, it has been modified to provide additional functionality with little expense. An already operating hydraulic control can then be reset simply by replacing the block.

An embodiment according to claim 3 corresponds to a modern unit construction principle for obtaining components which can be selectively combined. The component units can be easily integrated into the pilot circuit at the appropriate locations. In the case of systems that have not been attenuated before, the possibility of attenuation is subsequently obtained by installing a component unit. If desired, the component units are integrated into the main circuit, in which case the bypass line and the interference aperture are increased in size.

The cooperation between the aperture opening and the interference aperture opening through which the interference volume discharged from the pilot line passes.
The result is a fast-acting damping of pressure fluctuations.

If the size of the interference diaphragm opening exceeds that of the diaphragm opening, it must be expected that the opening of the load-bearing valve will be impeded, but it is surprising that this is commonly found in claim 5. Without a design, an unexpected damping effect would be achieved and the cargo support valve would operate undisturbed.

The hole used as the aperture has, for example, a diameter of about 0.8 mm, and the hole used as the interference aperture has, for example, a diameter of about 1.0 mm. The ratio and size of the holes are always adapted to the respective requirements in each individual case.

In the embodiments described above, the bypass line branches off from the pilot line. However, it is also possible to arrange a bypass line in the cylinder containing the control piston of the load support valve or in the control piston itself and connect it to the cylinder member at the back of the control piston, but in any case the cylinder The member is ventilated.

The kinetic damping restrictor is adapted to a pressure medium having an operating temperature or, for another reason, when the pressure medium is cold or in response to a sudden command, the rapid closing of the load support valve. Tightly adjusted to delay. This results in after-running of the liquid-using device under load. A non-return valve in a parallel line eliminates this danger according to claim 7, in that the pressure in said one main line and the pilot line is lower than the pressure opposing the closing movement of the load-bearing valve. In this case, the non-return valve causes a rapid outflow of the pressure medium through the damping throttle in order to close the load-carrying valve. In the case of a pressure drop in said one main line, the check valve is kept closed. If pressure fluctuations occur while the load is descending, the pressure medium is moved through the kinetic damping restrictor and the extreme pressure drop in one of the main lines has the effect that the check valve is opened for a short time. And thus the check valve contributes to the damping effect. If the pressure medium is cold or the motion damping throttle is tightly adjusted, no afterrunning occurs.

In the case of the embodiment according to claim 8, the damping device and the motion damping throttle work in such a way that the best possible damping effect is achieved.

The closing movement of the control piston is not impeded by the check valve according to claim 9, since the pressure medium flows out via the bypass line.

The pressure medium flowing out through the bypass line and the interference throttle opening according to claim 10 flows into the main line containing the load support valve. The connection between the bypass line and the reservoir can be omitted. Even if pressure is applied to other main lines by the check valve provided in the bypass line,
It is ensured that no flow of the pressure medium through the bypass line to the one main line takes place.

According to the eleventh aspect, the main line is not used for discharging the pressure medium flowing out for the purpose of attenuating the pressure fluctuation.

The pressure accumulation according to the twelfth aspect contributes to the rapid decay of the pressure fluctuation.

In another suitable embodiment, a load-carrying valve in which a sealing member is pressed by a spring force in a closing direction onto a valve seat located in the main line, and a sealing member in the pilot line. Claim 13 discloses an embodiment in which a control piston which operates at a pressure of 0.1 mm and applies a load to the sealing member in the opening direction is provided. Typically, a 1: 3 geometric area ratio between the valve seat and the control piston is used for hydraulic controllers for oscillating cargo transfer systems throughout the world. This has proven particularly useful in the case of double-acting differential hydraulic cylinders. By deviating from this area ratio, which has become generally accepted as a standard,
The resulting differential pressure from the pressure medium flowing out via the bypass line is compensated, and a large amount of force is applied to the control piston in order to achieve an effective damping and also to open the same force as before. The advantage is obtained that the pressure medium is moved.

A person skilled in the art according to claim 14 can easily understand the teachings as to how the best possible damping of the pressure fluctuations can be obtained without any change in the control behavior of the hydraulic control device. Is given.

According to the fifteenth aspect, both main lines of the liquid using device are secured by the cargo support valve. Regardless of the direction of movement of the load, effective damping of pressure fluctuations is achieved. The provision of interconnected bypass lines further simplifies the arrangement from a structural point of view.

An embodiment of the present invention will be described with reference to the drawings.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An oscillating cargo transfer system S according to FIG. 1 is, for example, a hydraulic crane 3 mounted on a truck 1 on a vehicle frame 2 of which the boom member is a cargo F.
Is moved by a liquid using device V, for example, a double acting hydraulic cylinder. A force is also generated at the beginning and end of or during the movement of the load F, which causes the boom member to oscillate due to a particularly large leverage, thereby producing appreciable pressure fluctuations in the fluid application V. This in turn results in dangerous or offensive cargo movement.

FIG. 2 is a block diagram showing, for example, a hydraulic control device L for differentially operating the left liquid using device V.
The above-mentioned liquid using device V is shown in FIG. Hydraulic control device L includes a pilot circuit A and a damping device X and a cargo support valve H including a control valve C schematically indicated, so that the pressure medium from pressure source P with T coupled thereto is there. Supplied.

This liquid-using device V is a double-acting differential cylinder 4 with a piston 5 actuated by a load F via a piston rod 8. The chambers 6, 7 of the cylinder 4 are connected via main lines 9, 10 to a control valve C, which are adapted to alternately connect to a pressure source P or T to move the piston 5 in both directions. I have. To stop the load, the control valve is provided with a zero position. The load support valve H is located in the other main line 9 and it adds the opening pressure from said one main line 10 to lower the load F, said opening pilot pressure being the control valve Adjusted by C.

Load is applied to the load support valve H in the closing direction by the spring 12 and also by the pilot pressure in the pilot line 15b which branches off from a part of the other main line 9 towards the control valve C. A valve 11 with a sealing member 13 is included. A check valve 14 that shuts off in the direction toward the control valve C as seen in the flow direction is circulating around the valve 11. In the opening direction, the pilot line 15a
The pilot member 15 is actuated against the force of the spring 12, but the pilot line 15a is not shown in the drawing, and a part of the other main line 9 towards the liquid application device V It has branched.

The pilot circuit A is provided with a pilot line 16 which branches from the branch 17 of the one main line 10 and reaches a connection portion 18 of the valve 11. Sealing member 13
In order to dampen the movement of the control piston (see FIG. 5) used and associated with it and to move the closure member to its open position, the pilot line 16
A component 19 can be included which preferably comprises an adjustable damping throttle 20 and a bypass check valve 21 which shuts off in the direction of said one main line 10. Even if the bypass check valve 21 is not provided, the closing and opening movement of the sealing member 13 is attenuated.

The bypass conduit 23 from the branch 22 of the pilot line 16 is branched, the interference aperture D ₂ are included in the bypass conduit 23. In the case of this embodiment, the bypass line 23 leads to a junction 24 located on a part of the other main line 9 towards the control valve C. Although aperture D ₁ stop between the branch of the pilot conduit 16 17 and 22 is provided, which is smaller than the interference aperture D ₂ (e.g. aperture D
₁ 0.8 mm, the interference aperture D ₂ is 1.0 mm). A check valve 25 for blocking the direction toward the interference aperture D _2, may be provided between the interference and aperture aperture D ₂ and the junction point 24.

In the position shown in FIG. 2, the valve 11 is holding a load. The check valve 14 is closed. A part of the main line 9 located between the load support valve H and the control valve C includes:
Therefore, it is ventilated to T.

To raise the load F, the control valve C is shifted so that the main line 9 is connected to the pressure source P and the main line 10 is connected to the reservoir T. The sealing member 13 is still in its closed position. The check valve 14 is opened. Room 7
Is pressured there. The piston 5 is extended.
The pressure medium is discharged from the chamber 6 via the main line 10.

In order to stop the load F, the control valve C returns to its previous position and the condition according to FIG. 2 is restored.

In order to lower the load F, pressure is applied to the chamber 6 and the pilot line 16, by which the sealing member 13 is opened against the force of the spring 12. Cargo F begins to sink. The pressure medium flows continuously through the bypass line 23 to the other main line 9 communicating with T. When pressure fluctuation in the pilot circuit of the chamber 6,7 in and cargo support valve H main conduit 9, 10 is generated, the pressure fluctuations by the pressure medium flowing out through the aperture D ₂ stop interfering with the bypass conduit 23 And is also damped by the motion damping diaphragm 20.

In order to stop the load F, one main conduit 10 is ventilated. Check valve 14 is in its closed position. The sealing member 13 is moved to its closed position, which movement is damped by the movement damping restrictor 20. The pressure medium flows into said one main line 10 and / or is discharged via a bypass line 23 via a check valve 25.

The hydraulic control device H according to FIG. 3 differs from that according to FIG. 2 by the fact that the bypass line 23 is in direct communication with the reservoir T. Furthermore, the pilot line 16 is provided with a check valve 26 which shuts off in the direction toward one main line 10. In the embodiment according to FIG. 2, the check valve 26 can also be arranged at the same position. The functions of the control device correspond to those of the control device shown in FIG. The only difference is that the pressure medium cannot flow back into said one main line 10.

According to FIG. 4, the pilot line 16 has connected thereto a sump 27 which is most conveniently located between the component 19 and the branch 22. The check valve 26 of FIG. 3 may be provided at the same position. Furthermore, it is schematically shown that the bypass line 23 reaches either directly into the reservoir T or, as in the case of FIG. 2, into the second main line 9.

In FIG. 5, the liquid using device V (eg, the buckling cylinder in FIG. 1) is protected by the load support valve H in both directions of operation. The bypass lines 23 of both damping devices X are connected to the respective other main lines 16.
Connected to

FIG. 6 shows a schematic view of the load support valve 11. The sealing member 13 configured as a ball 29 is pressed onto a valve seat 30 by a spring 12 in its housing 28, said valve seat 30 interconnecting the two chambers 31,32. The chamber 31 connects there to a part of the other main line 9 leading to the chamber 7, and the chamber 32 connects there to a part of the main line 9 leading to the control valve C. Check valves 14 are chambers 31 and 32
Located between. The control piston 34 is a tappet 33
To move the sealing member 13 to its open position via a pressure line in the pilot line 16. Chamber part 3 located behind control piston 34
5 is ventilated. The valve seat 30 has a cross-sectional area A ₁ , the cross-sectional area A ₁ and the pressure-activated control piston 34.
Of the area A _2, 1: than atmospheric, preferably 4 1: 6.5
It has a larger geometric area ratio. The pressure in the chamber 32 acts on the sealing member 13 in the closing direction parallel to the spring 12. The pressure in the chamber 31 acts on the sealing member 13 in the opening direction parallel to the control piston 34.

The bypass line 23 is also connected to the control piston 3
4 can extend into the chamber 35 through, aperture D ₂ stop interfering therewith may be inclusions. However, bypass line 23
Can be arranged such that its outlet is located on the side of the pressure-actuated open piston 34.

FIG. 7 shows that the vertical axis represents the pressure and the horizontal axis represents the pressure.
FIG. 4 shows a diagram in which the lines indicate time. Curve D₁₇Is
It is representative of the behavior of the pressure in the branch 17. under
Curve D₁₈Is representative of the pressure behavior at connection 18
It is something. Both pressures fluctuate violently at first,
After sedation, finally they remain constant. Vipa
Pipe 23 and interference aperture D_TwoAnd the pressure flowing out via
Pressure P due to force medium ₁₇, P₁₈Pressure difference dP exists between
You. This differential pressure is applied to the pressure operated control piston 34.
Due to the size of the area shown in FIG.
Compensated to work in a manner.

In one specific embodiment, the stop aperture D ₁ has a diameter of 0.8 mm and the interference stop aperture D ₂ has a diameter of 1.0 m.
m and the control piston 34 has a diameter of 17 mm. The pressure at branch 17 is about 90 bar and the pressure P _{18 at} connection ₁₈ is about 40 bar. Differential pressure of approximately 40bar is removed via the bypass conduit 23 and the interference aperture D _2.

In the case of the hydraulic control device L according to FIG.
In addition to the embodiment of FIG. 2 or FIG. 3, a parallel line 36 is provided, which branches off from the pilot line 16 between the component 19 and the valve 11 and is connected to the throttle opening D ₁ and the branch 1
7 ends in a pilot line 16. It includes a check valve 37 which bypasses the motion damping throttle 20 and opens in the direction of said one main line 10. Further, the parallel conduit 36 can be directly connected to the one main conduit 10. In the case of a cold pressure medium, or in the case of a tightly regulated damping throttle, the check valve 37 has a valve 1
The effect is that the pressure medium flows out through the throttle 20 in order to close the 1 quickly. Further, the check valve 3
7 contributes to the damping effect because it can eliminate pressure peaks. The bypass line 23 is connected to the other main line 9
Or directly to T. If pressure fluctuations in the system, check valve 37 by the pressure existing in the aperture D ₁ is kept remains closed, thus motion damping throttle 20 is effective at the desired manner.

The damping device X, with or without the check valve 37, is susceptible to rocking and provides a relatively complex control valve, including a supply flow regulator and load pressure detection, for a load transfer system. Particularly advantageous for control devices, the control valves operate on the one hand in a manner independent of pressure fluctuations on the pump side and independently of the load, but on the other hand themselves generate or maintain pressure fluctuations in the system. Show a tendency to. With an embodiment according to the invention, the pressure fluctuations in this system are independent of their origin,
Effectively and quickly attenuated.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an oscillating load transfer system.

FIG. 2 is a block diagram showing a hydraulic control device.

FIG. 3 is a diagram showing a modification of details.

FIG. 4 shows a modification of another detail.

FIG. 5 shows a further modification of the details.

FIG. 6 is a schematic sectional view of a cargo support valve.

FIG. 7 shows the pressure / pressure showing the damping effect in the hydraulic control device.
Time line diagram.

FIG. 8 is a block diagram of another embodiment.

[Description of Signs] 9, 10 Main line 13 Sealing member 16 Pilot line 20 Motion attenuation restrictor 21 Bypass check valve 17, 22 Branch 23 Bypass line 25, 26, 37 Check valve 30 Valve seat 34 Control piston 36 Parallel Pipe B Block C Control valve D ₁ Throttle opening D ₂ Interference throttle opening H Cargo support valve P Pressure source T For V Double-acting liquid use equipment X Hydraulic pressure attenuator

Claims (15)

(57) [Claims] 1. A hydraulic system for a moving system for a oscillating load.
In the control unit, two separate main lines (9), (10) and
Pressure source (P) or via (T) via control valve (C)
Double-acting liquid-using device adapted to be selectively connected to
(V), further comprising the control valve (C) and the liquid use device
The main pipelines (9) and (10) between the
And via one of the pilot lines (16)
Opened by another of said main lines (9), (10)
Control device including a load support valve (H) adapted for use
, The pilot line of the load support valve (H)
(16) has therein the pilot line (16)
Branch and interference aperture (D _Two) With bypass line
(23) A hydraulic pressure damping device for damping pressure fluctuations.
(X) is arranged, the hydraulic control device characterized by the above-mentioned.
Place. 2. The hydraulic control device according to claim 1, wherein the damping device (X) is incorporated in a block (B) including the load support valve (H). Control device. 3. The hydraulic control device according to claim 1, wherein the damping device (X) is connected to the load support valve (H).
A hydraulic control device, characterized in that it is an independent component unit connected to said pilot line (16). 4. The hydraulic control device according to claim 1, wherein the pilot line (22) between the branch (22) of the bypass line (23) and the main line (10). 16) A hydraulic control device characterized in that a throttle opening (D ₁ ) is provided inside. 5. The hydraulic control device according to claim 4, wherein the interference aperture (D ₂ ) is set to the aperture aperture (D ₂ ).
A hydraulic control device characterized by being larger than ₁ ). 6. The hydraulic control device according to claim 5, wherein a diameter ratio of the apertures (D ₁ ) and (D ₂ ) is about 1: 1.25. apparatus. 7. The hydraulic control apparatus according to claim 1, wherein the motion damping throttle (20) and the bypass check valve (21) for the motion damping throttle (20) are connected to the pilot pipe. A hydraulic control device provided in the passage (16) and wherein the bypass check valve (21) is opened in the opening direction of the load support valve (H);
A non-return valve (37) that opens in a direction toward the end is arranged in a parallel line (36) circumventing the motion damping restrictor (20), and the parallel line (36) is connected to the restrictor opening ( D ₁₎ and said main conduit (10) and a hydraulic control device which is connected the pilot line to (16), or and in that connected to the directly to the main conduit (10) between the. 8. The hydraulic control device according to claim 1, wherein the bypass line (23) includes the motion damping throttle (20) and the throttle opening (D). ₁ ) a hydraulic control device which branches off from the pilot line (16). 9. The hydraulic control device according to claim 8, wherein a check valve (26) closing in a direction toward the main line (10) is provided between the throttle opening (D ₁ ) and the main line (10). ), Which is disposed in the pilot line (16). 10. The hydraulic control device according to claim 4, wherein the bypass is connected to the main line (9) including the load support valve (H) on the discharge side. A pipe (23) connected thereto, and a check valve (25) closing in a direction toward the pilot pipe (16).
Is disposed in the bypass line (23) between the interference stop opening (D ₂ ) and the main line (9). 11. The hydraulic control device according to claim 4, wherein the bypass line (23) is connected directly to the reservoir (T). Hydraulic control device. 12. The hydraulic control device as claimed in claim 1, wherein a pressure reservoir (27) is provided with the diaphragm opening (D ₁ ) and the interference diaphragm opening (D ₂ ). And a hydraulic control device connected to the pilot line (16). 13. The hydraulic control device according to claim 1, wherein a spring is mounted in a closing direction on a valve seat (30) located in the main line (9). A sealing member (13) pressed by the force of the above and a control piston (34) receiving the action of the pressure in the pilot line (16) and applying a load to the closing member in the opening direction are provided by the load supporting valve. In the hydraulic control device provided in (H), a geometric area ratio (A ₁ : A ₂ ) between the valve seat (30) and the area of the control piston (34) subjected to pressure is applied. ) Is greater than 1: 4, preferably 1: 6.5
A hydraulic control device characterized by being larger. 14. The hydraulic control device according to claim 1, wherein the geometric area ratio between the control piston (34) and the valve seat (30) is adjusted. A ₁ : A ₂ ), the aperture (D ₁ ),
A selectable ratio between the diameter ratio of (D ₂ ) and the pressure in the main line (10) providing the opening pressure (P ₁₈ ) at the control piston (34) and the opening pressure (P ₁₇ ). Hydraulic control devices, characterized in that they are adapted to one another in such a way that a rapid decay of pressure fluctuations in the fluid-using appliance (V) is achieved. 15. The hydraulic control device according to claim 1, wherein both of the main lines (9) and (10) of the liquid using device (V) are the cargo. A support valve (H), and the load supporting valve (H) is provided with a damping device (X);
3) are interconnected.