Load-adapting rotary cushion valve and load-adapting rotary hydraulic system

Abstract

Disclosed are a load-adaptive slewing cushion valve and hydraulic system. The load-adaptive slewing cushion valve comprises: an oil inlet P, configured to be connected to an oil supply pipeline of hydraulic oil; an oil return port T, configured to be connected to a hydraulic oil tank; a working oil port A, configured to be connected to one end of a slewing motor; and a working oil port B, configured to be connected to the other end of the slewing motor; wherein a port P of an oil inlet control valve is connected to the oil inlet P; a port P1 of the oil inlet control valve is connected to the hydraulic oil tank by a pressure equalizing valve; a port A of the oil inlet control valve is respectively connected to the working oil port A, an inlet of a first oil replenishment overflow valve, and a port A of an oil return control valve; a port B of the oil inlet control valve is respectively connected to the working oil port B, an inlet of a second oil replenishment overflow valve, and a port B of the oil return control valve; an outlet of the first oil replenishment overflow valve, an outlet of the second oil replenishment overflow valve, and a port T of the oil return control valve are respectively connected to the oil return port T. The present invention has the characteristics that the control range of a slewing control handle is not affected by a load and the stop impact is small.

Description

BACKGROUND OF THE INVENTION1. Technical Field

[0001] The present invention belongs to the technical field of hydraulic valves, and in particular relates to a load-adaptive slewing cushion valve and hydraulic system.2. Description of Related Ar

[0002] Construction machinery with large-inertia slewing mechanisms, such as truck cranes, crawler cranes, and truck-mounted cranes, have different slewing inertias due to different boom lengths and hoisting weights. Under medium-long boom and heavy-load conditions, a slewing control handle has a small control range and a large stop impact, resulting in slewing shaking, and this seriously affects the controllability and safety of the entire machine operation.BRIEF SUMMARY OF THE INVENTION

[0003] To solve the deficiencies in the prior art, the present invention provides a load-adaptive slewing cushion valve and hydraulic system, with the characteristics that the control range of the slewing control handle is not affected by the load and the stop impact is small.

[0004] To achieve the above objective, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, provided is a load-adaptive slewing cushion valve, comprising: an oil inlet P, configured to be connected to an oil supply pipeline of hydraulic oil; an oil return port T, configured to be connected to a hydraulic oil tank; a working oil port A, configured to be connected to one end of a slewing motor; and a working oil port B, configured to be connected to the other end of the slewing motor, wherein a port P of an oil inlet control valve is connected to the oil inlet P; a port P1 of the oil inlet control valve is connected to the hydraulic oil tank by a pressure equalizing valve; a port A of the oil inlet control valve is respectively connected to the working oil port A, an inlet of a first oil replenishment overflow valve, and a port A of an oil return control valve; a port B of the oil inlet control valve is respectively connected to the working oil port B, an inlet of a second oil replenishment overflow valve, and a port B of the oil return control valve; an outlet of the first oil replenishment overflow valve, an outlet of the second oil replenishment overflow valve, and a port T of the oil return control valve are respectively connected to the oil return port T.

[0006] Further, the load-adaptive slewing cushion valve further comprises: a control oil port a, configured to be connected to a pilot handle oil port for controlling right slewing; and a control oil port b, configured to be connected to a pilot handle oil port for controlling left slewing; wherein the control oil port a and the control oil port b are respectively connected to two control oil ports of the oil inlet control valve.

[0007] Further, the load-adaptive slewing cushion valve further comprises: a first solenoid reversing valve, wherein an inlet of the first solenoid reversing valve is connected to the oil inlet P, and an outlet of the first solenoid reversing valve is connected to a shuttle valve by means of a fifth one-way valve and to the hydraulic oil tank by means of a soft overflow valve and a second solenoid reversing valve; the shuttle valve is connected between the working oil port A and the working oil port B.

[0008] Further, when a pilot handle is not operated, the control oil port a and the control oil port b have no pressure, the oil inlet control valve and the oil return control valve remain in a middle position and do not reverse the direction; the first solenoid reversing valve and the second solenoid reversing valve are not energized; hydraulic oil enters the pressure equalizing valve via the port P1 of the oil inlet control valve and returns to the hydraulic oil tank via the pressure equalizing valve.

[0009] Further, when a crane works to lift a heavy object, if a wire rope is not perpendicular to the heavy object, the first solenoid reversing valve is energized. The working oil port A and the working oil port B are connected to the oil inlet port P by means of the first solenoid reversing valve to realize the alignment of the wire rope with the heavy object.

[0010] Further, a port Lsa of the oil inlet control valve is respectively connected to a first gap damper, a first one-way valve and a third one-way valve by means of a first damper; the third one-way valve is connected to a spring chamber of the pressure equalizing valve by means of a third damper and to the hydraulic oil tank by means of a fourth damper; the third one-way valve is also connected to a second damper, a second gap damper and a second one-way valve by means of a fourth one-way valve; the second damper is connected to a port Lsb of the oil inlet control valve; a port sa of the oil return control valve is connected to the first gap damper and the first one-way valve, and a port sb of the oil return control valve is connected to the second gap damper and the second one-way valve.

[0011] Further, when the pilot handle is controlled to slew right, a pressure at the control oil port a gradually increases and at this moment, the oil inlet control valve gradually reverses the direction, and a throttle port from the oil inlet port P to the port P1 of the oil inlet control valve is narrowed gradually to closed, a throttle port from the oil inlet port P to the working oil port A is widened gradually to fully open, a path between the port Lsa of the oil inlet control valve and the oil return port T is cut off, the port Lsb of the oil inlet control valve is connected to the oil return port T, the port B of the oil inlet control valve is closed, the pressure at the port A of the oil inlet control valve is built up, the pressure at the working oil port A is fed back to the port sa of the oil return control valve via the port Lsa of the oil inlet control valve, the first damper, the first gap damper and the first one-way valve to push the oil return control valve to reverse the direction, a throttle port for the port B of the oil return control valve to return oil via the port T of the oil return control valve is widened gradually, the port A of the oil return control valve is closed and at the same time, the pressure at the working oil port A is fed back to the spring chamber of the pressure equalizing valve via the port Lsa of the oil inlet control valve, the third one-way valve and the third damper to narrow the opening of the pressure equalizing valve; at this moment, the hydraulic oil from the oil inlet port P is output to the working oil port A via the oil inlet control valve to control a slewing mechanism to slew right; and the hydraulic oil from the working oil port B enters the hydraulic oil tank via the oil return control valve.

[0012] Further, when the pressure at the working oil port A exceeds a set value, the corresponding first oil replenishment overflow valve is opened to protect a system pressure from exceeding the set value.

[0013] Further, when the slewing mechanism stops right slewing, the pressure at the working oil port A decreases and at this moment, the hydraulic oil is replenished to the working oil port A by the first oil replenishment overflow valve, thereby preventing the slewing mechanism from sucking air.

[0014] Further, when the slewing mechanism stops right slewing, the pressure at the working oil port B increases because the oil return control valve is closed; at this moment, the second solenoid reversing valve is closed with a delay, and the pressure at the working oil port B is unloaded by means of the shuttle valve, the fifth one-way valve, the soft overflow valve, and the second solenoid reversing valve to avoid stop impact.

[0015] In a second aspect, provided is a load-adaptive slewing hydraulic system, comprising the load-adaptive slewing cushion valve described in the first aspect, wherein the oil inlet P of the load-adaptive slewing cushion valve is connected to an outlet of a metering pump by the oil supply pipeline, and the oil return port T of the load-adaptive slewing cushion valve is connected to the hydraulic oil tank; the working oil port A of the load-adaptive slewing cushion valve is connected to the port A of the slewing motor; the working oil port B of the load-adaptive slewing cushion valve is connected to the port B of the slewing motor; the control oil port a of the load-adaptive slewing cushion valve is connected to the pilot handle oil port for controlling right slewing; the control oil port b of the load-adaptive slewing cushion valve is connected to the pilot handle oil port for controlling left slewing.

[0016] Compared with the prior art, the present invention has the following beneficial effects. In the present invention, the port P of the oil inlet control valve is connected to the oil inlet P; the port P1 of the oil inlet control valve is connected to the hydraulic oil tank by the pressure equalizing valve; the port A of the oil inlet control valve is respectively connected to the working oil port A, the inlet of the first oil replenishment overflow valve, and the port A of the oil return control valve; the port B of the oil inlet control valve is respectively connected to the working oil port B, the inlet of the second oil replenishment overflow valve, and the port B of the oil return control valve; the outlet of the first oil replenishment overflow valve, the outlet of the second oil replenishment overflow valve, and the port T of the oil return control valve are respectively connected to the oil return port T. In this way, the control range of the slewing control handle of a large-inertia slewing mechanism is not affected by the load, and the present invention also has the characteristics of small stop impact, etc.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0017] Fig. 1 is a schematic diagram of a load-adaptive slewing cushion valve and hydraulic system according to an embodiment of the present invention; and Fig. 2 is a cross-sectional schematic diagram of a load-adaptive slewing cushion valve according to an embodiment of the present invention; in the figures, 1. metering pump; 2. oil inlet control valve; 3. oil return control valve; 4. first damper; 5. second damper; 6. first gap damper; 7. second gap damper; 8. first one-way valve; 9. second one-way valve; 10. third one-way valve; 11. fourth one-way valve; 12. third damper; 13. fourth damper; 14. pressure equalizing valve; 15. first oil replenishment overflow valve; 16. second oil replenishment overflow valve; 17. first solenoid reversing valve; 18. second solenoid reversing valve; 19. soft overflow valve; 20. fifth one-way valve; 21. shuttle valve; 22. slewing motor; 23. left end cover; 24. right end cover; 25. valve body. DETAILED DESCRIPTION OF THE INVENTION

[0018] The invention will be further described with reference to the accompanying drawings. The following embodiments are only for illustrating the technical solution of the invention more clearly, but not for limiting the scope of the invention.

[0019] It should be noted that, the directions or positional relationships indicated by terms such as "front", "rear", "left", "right", "up", "down", "inside" and "outside", as used herein, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention. The terms "front", "rear", "left", "right", "up" and "down", as used herein, refer to directions in the drawings, and the terms "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively.Embodiment 1:

[0020] As shown in Fig. 1 and Fig. 2, a load-adaptive slewing cushion valve comprises: an oil inlet control valve 2, an oil return control valve 3, a first damper 4, a second damper 5, a first gap damper 6, a second gap damper 7, a first one-way valve 8, a second one-way valve 9, a third one-way valve 10, a fourth one-way valve 11, a third damper 12, a fourth damper 13, a pressure equalizing valve 14, a first oil replenishment overflow valve 15, a second oil replenishment overflow valve 16, a first solenoid reversing valve 17, a second solenoid reversing valve 18, a soft overflow valve 19, a fifth one-way valve 20, and a shuttle valve 21.

[0021] High-pressure oil from the metering pump 1 is connected to port P of the oil inlet control valve 2 by the oil inlet port P of the load-adaptive slewing cushion valve and is also connected to the first solenoid reversing valve 17. A port A of the oil inlet control valve 2 is connected to a port A of the slewing motor 22 via a working oil port A, and a port B of the oil inlet control valve 2 is connected to a port B of the slewing motor 22 via a working oil port B; two ports T of the oil inlet control valve 2 which are connected together are connected to an oil return port T of the load-adaptive slewing cushion valve; a port Lsa of the oil inlet control valve 2 is connected to a port sa of the oil return control valve 3 via the first damper 4, the first gap damper 6 and the first one-way valve 8 and in the meanwhile, the port Lsa of the oil inlet control valve 2 is connected to a spring chamber of the pressure equalizing valve 14 via the third one-way valve 10 and the third damper 12; a port Lsb of the oil inlet control valve 2 is connected to a port sb of the oil return control valve 3 via the second damper 5, the second gap damper 7 and the second one-way valve 9 and in the meanwhile, the port Lsb of the oil inlet control valve 2 is connected to the spring chamber of the pressure equalizing valve 14 via the fourth one-way valve 11 and the third damper 12; a port P1 of the oil inlet control valve 2 is connected to one end of the pressure equalizing valve 14; a port T of the oil return control valve 3 is connected to the port T of the load-adaptive slewing cushion valve, a port A of the oil return control valve 3 is connected to the port A of the slewing motor 22 via the working oil port A, and a port B of the oil return control valve 3 is connected to the port B of the slewing motor 22 via the working oil port B; the other end of the pressure equalizing valve 14 is connected to the oil return port T of the load-adaptive slewing cushion valve, and the spring chamber of the pressure equalizing valve 14 is connected to the port T of the load-adaptive slewing cushion valve via the third damper 12 and the fourth damper 13; one end of the first oil replenishment overflow valve 15 is connected to the port A of the slewing motor 22 via the working oil port A, and the other end of the first oil replenishment overflow valve 15 is connected to the port T of the load-adaptive slewing cushion valve; one end of the second oil replenishment overflow valve 16 is connected to the port B of the slewing motor 22 via the working oil port B, and the other end of the second oil replenishment overflow valve 16 is connected to the port T of the load-adaptive slewing cushion valve; two oil ports of the slewing motor 22 are respectively connected to two ends of the shuttle valve 21; high pressure screened by the shuttle valve 21 passes through the fifth one-way valve 20 and is then respectively connected to the first solenoid reversing valve 17 and the soft overflow valve 19; one end of the soft overflow valve 19 is connected to the fifth one-way valve 20 and the first solenoid reversing valve 17, and the other end of the soft overflow valve 19 is connected to the second solenoid reversing valve 18; the other end of the second solenoid reversing valve 18 is connected to the oil return port T of the load-adaptive slewing cushion valve.

[0022] A control oil port a of the load-adaptive slewing cushion valve is connected to a pilot handle oil port for controlling right slewing, and a control oil port b of the load-adaptive slewing cushion valve is connected to a pilot handle oil port for controlling the left slewing.

[0023] When a slewing pilot handle is not operated, the control oil port a and the control oil port b of the load-adaptive slewing cushion valve have no pressure, the oil inlet control valve 2 and the oil return control valve 3 remain in a middle position and do not reverse the direction; the first solenoid reversing valve 17 and the second solenoid reversing valve 18 are not energized. Oil from the metering pump 1 enters the pressure equalizing valve 14 via port P1 of the oil inlet control valve 2, and the pressure equalizing valve 14 is opened to return oil.

[0024] When a crane works to lift a heavy object, if a wire rope is not perpendicular to the heavy object, the first solenoid reversing valve 17 is energized to connect port A and port B of the slewing motor 22 with the port P of the load-adaptive slewing cushion valve by means of the first solenoid reversing valve 17 to realize the alignment of the wire rope with the heavy object.

[0025] When the pilot handle for controlling right slewing is pushed step by step, a pressure at the control oil port a of the load-adaptive slewing cushion valve gradually increases and at this moment, the oil inlet control valve 2 gradually reverses the direction and a throttle port from the port P of the oil inlet control valve 2 to the port P1 of the oil inlet control valve 2 is narrowed gradually to closed, a throttle port from the port P of the oil inlet control valve 2 to the port A of the oil inlet control valve 2 is widened gradually to fully open, a path between the port Lsa of the oil inlet control valve 2 and the port T is cut off, the port Lsb of the oil inlet control valve 2 is connected to the oil return port T, the port B of the oil inlet control valve 2 is closed, the pressure at the port A of the oil inlet control valve 2 is built up, the pressure at the port A of the slewing motor 22 is fed back to the port sa of the oil return control valve 3 via the port Lsa of the oil inlet control valve 2, the first damper 4, the first gap damper 6 and the first one-way valve 8 to push the oil return control valve 3 to reverse the direction, the throttle port for the port B of the oil return control valve 3 to return oil via the port T is widened gradually, and the port A of the oil return control valve 3 is closed and at the same time, the pressure at the port A of the slewing motor 22 is fed back to the spring chamber of the pressure equalizing valve 14 via the port Lsa of the oil inlet control valve 2, the third one-way valve 10 and the third damper 12 to narrow the opening of the pressure equalizing valve 14; at the same time, the oil from the metering pump 1 pushes the slewing motor 22 to slew right via the oil inlet control valve 2, and the oil from the port B of the slewing motor 22 reaches the port T via the oil return control valve 3.

[0026] When the slewing mechanism slews right, if the pressure at port A of the load-adaptive slewing cushion valve is too high, the corresponding first oil replenishment overflow valve 15 is opened to protect the system pressure from exceeding a set value.

[0027] When the pilot handle for controlling right slewing gradually returns, the pressure at the control oil port a of the load-adaptive slewing cushion valve gradually decreases and at this moment, the oil inlet control valve 2 gradually returns to the middle position from a reversing position, the throttle port from the port P of the oil inlet control valve 2 to the port P1 of the oil inlet control valve 2 is widened gradually, the throttle port from the port P of the oil inlet control valve 2 to the port A of the oil inlet control valve 2 is narrowed to closed, the port Lsa of the oil inlet control valve 2 is connected to the port T, the port Lsb of the oil inlet control valve 2 is connected to the port T, the pressure at the port A of the oil inlet control valve 2 gradually decreases, the pressure at the port A of the slewing motor 22, which is fed back to the port sa of the oil return control valve 3 via the port Lsa of the oil inlet control valve 2, the first damper 4, the first gap damper 6 and the first one-way valve 8, decreases gradually, the oil return control valve 3 gradually returns to the middle position from a reversing position, and the throttle port for the port B of the oil return control valve 3 to return oil via the port T is narrowed gradually to closed and at the same time, the pressure at the port A of the slewing motor 22, which is fed back to the spring chamber of the pressure equalizing valve 14 via the port Lsa of the oil inlet control valve 2, the third one-way valve 10 and the third damper 12, decreases gradually, and the opening of the pressure equalizing valve 14 is widened; at this moment, the oil from the metering pump 1 enters the pressure equalizing valve 14 via the port P1 of the oil inlet control valve 2, and the pressure equalizing valve 14 is opened to return the oil, and then the slewing motor 22 stops slewing.

[0028] When the slewing mechanism stops right slewing, the slewing mechanism keeps rotating due to its inertia, and the pressure at the port A of the slewing motor 22 decreases and at this moment, the oil is replenished to the port A of the slewing motor 22 by the first oil replenishment overflow valve 15, thereby preventing the slewing motor 22 from sucking air.

[0029] When the slewing mechanism stops right slewing, the slewing mechanism keeps rotating due to its inertia. The pressure at port B of the slewing motor 22 increases because the oil return control valve 3 is closed; at this moment, the second solenoid reversing valve 18 is closed with a delay, and the pressure at port B of the slewing motor 22 is unloaded by means of the shuttle valve 21, the fifth one-way valve 20, the soft overflow valve 19, and the second solenoid reversing valve 18 to avoid stop impact.

[0030] The start and stop of the slewing motor to slew left are operated in the same way as the process described above.

[0031] As shown in Fig. 2, it is a cross-sectional structural diagram of the load-adaptive slewing cushion valve. The load-adaptive slewing cushion valve consists of three parts: a left end cover 23, a right end cover 24 and a valve body 25. The cross-sectional diagram includes the oil inlet control valve 2, the oil return control valve 3, the pressure equalizing valve 14, the first oil replenishment overflow valve 15, the second oil replenishment overflow valve 16, the first solenoid reversing valve 17, and the second solenoid reversing valve 18.

[0032] The left end cover 23 and the right end cover 24 are installed at two ends of the valve body 25 by bolts, the valve cores of the oil inlet control valve 2 and the oil return control valve 3 are installed in valve core holes of the valve body 25, and the first oil replenishment overflow valve 15, the second oil replenishment overflow valve 16, the first solenoid reversing valve 17, and the second solenoid reversing valve 18 are installed on the valve body 25 by threads.

[0033] When the control oil port a and the control oil port b of the load-adaptive slewing cushion valve have no pressure, the oil inlet control valve 2 and the oil return control valve 3 remain in a middle position and do not reverse the direction; the first solenoid reversing valve 17 and the second solenoid reversing valve 18 are not energized. The oil from port P of the oil inlet control valve 2 enters the pressure equalizing valve 14 via port P1 of the oil inlet control valve 2, and the pressure equalizing valve 14 moves up to open to return oil to port T.

[0034] When the pressure at the control oil port a of the oil inlet control valve 2 on the load-adaptive slewing cushion valve gradually increases, a valve core of the oil inlet control valve 2 gradually reverses the direction to the right, the throttle port from the port P of the oil inlet control valve 2 to the port P1 of the oil inlet control valve 2 is narrowed gradually to closed, the throttle port from the port P to the port A is widened gradually to fully open, a path between the port Lsa of the oil inlet control valve 2 and the port T is cut off, the port Lsb is connected to the port T, the port B of the oil inlet control valve 2 is closed, the pressure at the port A of the oil inlet control valve 2 is built up, the pressure at the port A of the slewing motor 22 is fed back to the port Lsa of the oil return control valve 3 via the port Lsa of the oil inlet control valve 2 to push the oil return control valve 3 to move to the right and reverse the direction, and the throttle port for the port B of the oil return control valve 3 to return oil via the port T is widened gradually, and the port A of the oil return control valve 3 is closed and at the same time, the pressure at the port A of the slewing motor 22 is fed back to the upper chamber of the pressure equalizing valve 14 via the port Lsa of the oil inlet control valve 2 to narrow the opening of the pressure equalizing valve 14; the oil from the port P of the oil inlet control valve 2 reaches the port A via the oil inlet control valve 2, and the oil from the port B reaches the port T via the oil return control valve 3.

[0035] When the pressure at the working oil port A of the load-adaptive slewing cushion valve is too high, the corresponding first oil replenishment overflow valve 15 is opened to protect a system pressure from exceeding a set value.

[0036] When the pressure at the control oil port a of the load-adaptive slewing cushion valve gradually decreases and at this moment, the oil inlet control valve 2 gradually moves to the left to return to the middle position from the reversing position, the throttle port from the port P of the oil inlet control valve 2 to the port P1 of the oil inlet control valve 2 is widened gradually, the throttle port from the port P to the port A is narrowed to closed, the port Lsa of the oil inlet control valve 2 is connected to the port T, the port Lsb is connected to the port T, the pressure at the port A of the oil inlet control valve 2 gradually decreases, the pressure at the port A of the slewing motor, which is fed back to the port sa of the oil return control valve 3 via the port Lsa of the oil inlet control valve 2, decreases gradually, the oil return control valve 3 gradually moves to the left to return to the middle position from the reversing position, and the throttle port for the port B of the oil return control valve 3 to return oil via the port T is narrowed gradually to closed and at the same time, the pressure at the port A of the slewing motor, which is fed back to the upper chamber of the pressure equalizing valve 14 via the port Lsa of the oil inlet control valve 2, decreases gradually, and the opening of the pressure equalizing valve 14 is widened; at this moment, the oil from the port P of the oil inlet control valve 2 passes through the port P1 of the oil inlet control valve 2 to push the pressure equalizing valve 14 to move up, and the pressure equalizing valve 14 is opened to return the oil to port T.

[0037] When the pressure at port A of the load-adaptive slewing cushion valve decreases due to inertia, the oil is replenished to port A by the first oil replenishment overflow valve 15 to avoid air suction.

[0038] Similar to the process described above, when the pressure at the control oil port b of the oil inlet control valve 2 on the load-adaptive slewing cushion valve increases, the oil inlet control valve 2 completely reverse the direction and when the pressure decreases, the oil inlet control valve 2 returns to the middle position.

[0039] The oil inlet control valve 2 on the load-adaptive slewing cushion valve of the present invention adopts an open center throttle system to reduce the flow stiffness during reversal and reduce the impact during direction reversing.

[0040] The present invention designs a pressure equalizing valve 14 on a P-to-T oil path so that pressure differences at two ends of the P-to-A / B throttle port and the P-to-T port are approximately equal. The control flow of the slewing valve is only related to the area of a throttle groove and is not affected by the load pressure, thereby improving the control range during slewing with a high load. Moreover, the control range will not change under saturated flow, thereby achieving better controllability.

[0041] In the present invention, the load feedback chamber of the pressure equalizing valve 14 is connected to port T by the fourth damper 13. When the load-adaptive slewing cushion valve is in the middle position, the spring chamber of the pressure equalizing valve 14 relieves the pressure to avoid the pressure build-up of the load-adaptive slewing cushion valve.

[0042] In the present invention, a load signal is screened by the valve core of the oil inlet control valve 2. When the valve core is in the middle position, the pressure of a load signal chamber can be relieved by means of port T. During direction reversing, only the load pressure of one chamber of port A or B is fed back, and the pressure of the other chamber is relieved by means of the T port, thereby avoiding the flow error distribution caused by the feedback of the pressure from the oil return port due to the high impact pressure of the oil return port during slewing.

[0043] The present invention uses the oil inlet control valve to screen the oil inlet load pressure to control the opening of a throttle groove of the oil return control valve, thereby realizing adaptive control of different inertial loads, and achieving better controllability of slewing stop and a larger control range.

[0044] The slewing oil inlet pressure of the present invention controls the opening and closing of the throttle valve core of the oil return control valve 3 by means of the one-way gap damper composed of the first gap damper 6 (the second gap damper 7) and the first one-way valve 8 (the second one-way valve 9). When the slewing oil inlet pressure fluctuates, the gap damper can filter the pressure fluctuation, and the one-way valve can realize the rapid closing of the valve core.

[0045] The present invention adopts the soft overflow valve 19 and the second electromagnetic reversing valve 18 to reduce the stop impact of slewing. When the adaptive slewing mechanism starts to stop, the second solenoid reversing valve 18 is closed with a delay. At this moment, the oil return impact pressure caused by slewing is relieved by means of the soft overflow valve 19. When the slewing mechanism works at a high speed, the pressure of the soft overflow valve 19 is high. When the slewing mechanism works at a low speed, the pressure of the soft overflow valve 19 is low, thereby avoiding the stop impact of the slewing mechanism.Embodiment 2:

[0046] Based on the load-adaptive slewing cushion valve described in Embodiment 1, this embodiment provides a load-adaptive slewing hydraulic system, comprising the load-adaptive slewing cushion valve described in Embodiment 1, wherein the oil inlet P of the load-adaptive slewing cushion valve is connected to an outlet of a metering pump 1 by an oil supply pipeline, and the oil return port T of the load-adaptive slewing cushion valve is connected to a hydraulic oil tank; the working oil port A of the load-adaptive slewing cushion valve is connected to the port A of the slewing motor 22; the working oil port B of the load-adaptive slewing cushion valve is connected to the port B of the slewing motor 22; the control oil port a of the load-adaptive slewing cushion valve is connected to the pilot handle oil port for controlling right slewing; the control oil port b of the load-adaptive slewing cushion valve is connected to the pilot handle oil port for controlling left slewing.

[0047] The above are only the preferred embodiments of the invention. It should be pointed out that those of ordinary skill in the art can also make several improvements and modifications without departing from the technical principles of the invention, and these improvements and modifications should also be regarded as falling within the scope of the invention.

Claims

1. A load-adaptive slewing cushion valve, comprising: an oil inlet P, configured to be connected to an oil supply pipeline of hydraulic oil; an oil return port T, configured to be connected to a hydraulic oil tank; a working oil port A, configured to be connected to one end of a slewing motor; and a working oil port B, configured to be connected to the other end of the slewing motor; a port P of an oil inlet control valve (2) is connected to the oil inlet P; a port P1 of the oil inlet control valve (2) is connected to the hydraulic oil tank by a pressure equalizing valve (14); a port A of the oil inlet control valve (2) is respectively connected to the working oil port A, an inlet of a first oil replenishment overflow valve (15), and a port A of an oil return control valve (3); a port B of the oil inlet control valve (2) is respectively connected to the working oil port B, an inlet of a second oil replenishment overflow valve (16), and a port B of the oil return control valve (3); an outlet of the first oil replenishment overflow valve (15), an outlet of the second oil replenishment overflow valve (16), and a port T of the oil return control valve (3) are respectively connected to the oil return port T.

2. The load-adaptive slewing cushion valve according to claim 1, further comprising: a control oil port a, configured to be connected to a pilot handle oil port for controlling right slewing; and a control oil port b, configured to be connected to a pilot handle oil port for controlling left slewing; wherein the control oil port a and the control oil port b are respectively connected to two control oil ports of the oil inlet control valve (2).

3. The load-adaptive slewing cushion valve according to claim 2, further comprising: a first solenoid reversing valve (17), wherein an inlet of the first solenoid reversing valve (17) is connected to the oil inlet P, and an outlet of the first solenoid reversing valve (17) is connected to a shuttle valve (21) by means of a fifth one-way valve (20) and to the hydraulic oil tank by means of a soft overflow valve (19) and a second solenoid reversing valve (18); the shuttle valve (21) is connected between the working oil port A and the working oil port B.

4. The load-adaptive slewing cushion valve according to claim 3, wherein, when a pilot handle is not operated, the control oil port a and the control oil port b have no pressure, the oil inlet control valve (2) and the oil return control valve (3) remain in a middle position and do not reverse the direction; the first solenoid reversing valve (17) and the second solenoid reversing valve (18) are not energized; hydraulic oil enters the pressure equalizing valve (14) via the port P1 of the oil inlet control valve (2) and returns to the hydraulic oil tank via the pressure equalizing valve (14).

5. The load-adaptive slewing cushion valve according to claim 3, wherein, when a crane works to lift a heavy object, if a wire rope is not perpendicular to the heavy object, the first solenoid reversing valve (17) is energized, and the working oil port A and the working oil port B are connected to the oil inlet port P by means of the first solenoid reversing valve (17) to realize the alignment of the wire rope with the heavy object.

6. The load-adaptive slewing cushion valve according to claim 3, wherein a port Lsa of the oil inlet control valve (2) is respectively connected to a first gap damper (6), a first one-way valve (8) and a third one-way valve (10) by means of a first damper (4); the third one-way valve (10) is connected to a spring chamber of the pressure equalizing valve (14) by means of a third damper (12) and to the hydraulic oil tank by means of a fourth damper (13); the third one-way valve (10) is also connected to a second damper (5), a second gap damper (7) and a second one-way valve (9) by means of a fourth one-way valve (11); the second damper (5) is connected to a port Lsb of the oil inlet control valve (2); a port sa of the oil return control valve (3) is connected to the first gap damper (6) and the first one-way valve (8), and a port sb of the oil return control valve (3) is connected to the second gap damper (7) and the second one-way valve (9).

7. The load-adaptive slewing cushion valve according to claim 6, wherein, when the pilot handle is controlled to slew right, a pressure at the control oil port a gradually increases and at this moment, the oil inlet control valve (2) gradually reverses the direction, and a throttle port from the oil inlet port P to the port P1 of the oil inlet control valve (2) is narrowed gradually to closed, a throttle port from the oil inlet port P to the working oil port A is widened gradually to fully open, a path between the port Lsa of the oil inlet control valve (2) and the oil return port T is cut off, the port Lsb of the oil inlet control valve (2) is connected to the oil return port T, the port B of the oil inlet control valve (2) is closed, the pressure at the port A of the oil inlet control valve (2) is built up, the pressure at the working oil port A is fed back to the port sa of the oil return control valve (3) via the port Lsa of the oil inlet control valve (2), the first damper (4), the first gap damper (6) and the first one-way valve (8) to push the oil return control valve (3) to reverse the direction, a throttle port for the port B of the oil return control valve (3) to return oil via the port T of the oil return control valve (3) is widened gradually, the port A of the oil return control valve (3) is closed and at the same time, the pressure at the working oil port A is fed back to the spring chamber of the pressure equalizing valve (14) via the port Lsa of the oil inlet control valve ((2), the third one-way valve (10) and the third damper (12) to narrow the opening of the pressure equalizing valve (4); at this moment, the hydraulic oil from the oil inlet port P is output to the working oil port A via the oil inlet control valve (2) to control a slewing mechanism to slew right; and the hydraulic oil from the working oil port B enters the hydraulic oil tank via the oil return control valve (3).

8. The load-adaptive slewing cushion valve according to claim 6, wherein, when the pressure at the working oil port A exceeds a set value, the corresponding first oil replenishment overflow valve (15) is opened to protect a system pressure from exceeding the set value.

9. The load-adaptive slewing cushion valve according to claim 6, wherein, when the slewing mechanism stops right slewing, the pressure at the working oil port A decreases and at this moment, the hydraulic oil is replenished to the working oil port A by the first oil replenishment overflow valve (15), thereby preventing the slewing mechanism from sucking air.

10. The load-adaptive slewing cushion valve according to claim 6, wherein, when the slewing mechanism stops right slewing, the pressure at the working oil port B increases because the oil return control valve (3) is closed; at this moment, the second solenoid reversing valve (18) is closed with a delay, and the pressure at the working oil port B is unloaded by means of the shuttle valve (21), the fifth one-way valve (20), the soft overflow valve (19), and the second solenoid reversing valve (18) to avoid stop impact.

11. A load-adaptive slewing hydraulic system, comprising the load-adaptive slewing cushion valve according to any one of claims 1-10, wherein the oil inlet P of the load-adaptive slewing cushion valve is connected to an outlet of a metering pump (1) by the oil supply pipeline, and the oil return port T of the load-adaptive slewing cushion valve is connected to the hydraulic oil tank; the working oil port A of the load-adaptive slewing cushion valve is connected to a port A of the slewing motor (22); the working oil port B of the load-adaptive slewing cushion valve is connected to a port B of the slewing motor (22); the control oil port a of the load-adaptive slewing cushion valve is connected to the pilot handle oil port for controlling right slewing; the control oil port b of the load-adaptive slewing cushion valve is connected to the pilot handle oil port for controlling left slewing.

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