A large-tonnage crane hydraulic system based on a new priority valve

Abstract

This invention discloses a hydraulic system for a large-tonnage crane based on a novel priority valve. The hydraulic system comprises a main pump (1), a main pump (2), a multi-way valve (3), a main winch (4), an auxiliary winch (5), a luffing cylinder (6), a telescopic cylinder (7), a priority valve (8), and a super-lift system (9). The main pump (1), main winch (4), and auxiliary winch (5) are connected sequentially. The main pump (2) is connected to the priority valve (8), which in turn connects the super-lift system (9), telescopic cylinder (7), and luffing cylinder (6). The multi-way valve (3) regulates the flow rate of pressurized oil in each unit of the hydraulic system. This invention is applicable to ultra-large-tonnage cranes with super-lift capabilities. The super-lift hydraulic system and the telescopic, luffing, and winch systems can use a single pump to regulate flow, effectively reducing costs and minimizing the installation space required for the pump unit.

Description

Technical Field

[0001] The technical field of this invention relates to engineering machinery technology: engineering machinery products relying on hydraulic transmission, specifically to a priority valve and a hydraulic system having the valve assembly, and a crane. Background Technology

[0002] Currently, large-tonnage cranes are generally equipped with superlift devices. Superlifting effectively improves the crane's lifting performance. During the crane's boom extension and retraction, the superlift winch and superlift winch brake of the superlift system must operate simultaneously. To meet the requirements of this working condition, two sets of pumps are generally used for control: one set of pumps controls the boom extension and retraction, and the other set of pumps controls the superlift operation.

[0003] With the increasing demand for large-tonnage cranes equipped with superlifts in China, and the trend of cranes with superlift devices gradually shifting towards smaller tonnages, superlifts are now being added to cranes with tonnages of 300 tons or even smaller, whereas previously they were typically found on cranes over 500 tons. This places increasingly higher demands on cost and space constraints for components. Existing large-tonnage cranes with superlifts share a single pump control system for the telescoping, luffing, and hoisting systems, while the superlift system uses a separate pump control system. This results in multiple pump sets, high costs, and requires significant space for installation, making overall crane layout difficult. Summary of the Invention

[0004] Purpose of the Invention: The purpose of this invention is to design a hydraulic system for large-tonnage cranes based on a novel priority valve. When two hydraulic systems share a single pump, one system can be prioritized, with the remaining flow supplied to the other. This system is applicable to ultra-large-tonnage cranes with superlift mechanisms, where the superlift hydraulic system shares a single pump with the telescopic, luffing, and winch systems, effectively reducing costs and minimizing the installation space required for the pump unit.

[0005] The technical solution is as follows: A hydraulic system for a large-tonnage crane based on a novel priority valve, wherein the hydraulic system comprises a main pump (1), a main pump (2), a multi-way valve (3), a main winch (4), an auxiliary winch (5), a luffing cylinder (6), a telescopic cylinder (7), a priority valve (8), and a super-lifting system (9); the main pump (1) is connected to the main winch (4) and the auxiliary winch (5) in sequence; the main pump (2) is connected to the priority valve (8), and the priority valve (8) is connected to the super-lifting system (9), the telescopic cylinder (7), and the luffing cylinder (6); the multi-way valve (3) regulates the flow rate of pressurized oil in each unit of the hydraulic system.

[0006] Furthermore, the priority valve (8) includes an electro-proportional directional valve (10), a hydraulic directional valve (11), a speed control valve (12), a check valve (13), a check valve (14), and a damper (15). When the telescopic cylinder (7) and the super-lift system (9) work simultaneously, the pressure oil enters from port P, and the pressure oil flow flows out from port A of the priority valve (8), first satisfying the flow requirements of the super-lift system (9). The remaining pressure oil flow flows out from port B of the priority valve (8) and is used for the telescopic cylinder (7).

[0007] Furthermore, in the priority valve (8), if the hydraulic control directional valve (11) in the priority valve (8) is stuck or the electro-proportional directional valve (10) does not switch, the pressure oil cannot reach port A through the check valve (13). The check valve (14) and damper (15) are used to supply oil to the super-lift system (9), and the super-lift system (9) can still achieve emergency lowering.

[0008] Furthermore, a speed control valve (12) is provided in the priority valve (8) to make the electro-proportional directional valve (10) and the hydraulic directional valve (11) switch smoothly and reduce impact.

[0009] Furthermore, the speed control valve (12) is replaced with a damping network.

[0010] Furthermore, the super-lift system uses a single pump to regulate flow with the telescopic, luffing, and winch systems, effectively reducing costs and minimizing the installation space required for the pump unit.

[0011] Furthermore, when the telescopic cylinder (7) and the super-lift system (9) work simultaneously, the pressure oil enters from port P, passes through the hydraulic control directional valve (11) to reach the electro-proportional directional valve (10), the electro-proportional directional valve (10) provides a certain current value, the electro-proportional directional valve (10) switches, the pressure oil reaches the check valve (13), after passing through the check valve (13), it flows out from port A and is used for the super-lift system; after meeting the flow requirements of the super-lift system, the excess flow enters from port P, the hydraulic control directional valve (11) switches, the excess flow passes through the hydraulic control directional valve (11) to reach port B and is used for the telescopic cylinder.

[0012] Furthermore, the required flow rate of the super-start system (9) is controlled by the current value of the electro-proportional directional valve (10).

[0013] Furthermore, the hydraulic control directional valve (11) is a two-position three-way hydraulic control directional valve.

[0014] Furthermore, the electro-proportional directional valve (10) is a two-position two-way electro-proportional directional valve.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. Large-tonnage cranes with superlift systems share a single pump with the telescopic, luffing, and winch systems, effectively reducing costs and minimizing the installation space required for the pump unit.

[0017] 2. When two systems share a pump, one system can be prioritized, and the remaining flow can be supplied to the other system.

[0018] 3. When distributing traffic between the two systems, the switching is smooth and the impact is small. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the hydraulic system of the large-tonnage crane of the present invention;

[0020] Figure 2 This is a schematic diagram of the control principle of the novel priority valve of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0022] This invention proposes a hydraulic system for a large-tonnage crane based on a novel priority valve. The hydraulic system comprises a main pump 1, a main pump 2, a multi-way valve 3, a main winch 4, an auxiliary winch 5, a luffing cylinder 6, a telescopic cylinder 7, a priority valve 8, and a super-lifting system 9. The main pump 1 is connected to the main winch 4 and the auxiliary winch 5 in sequence. The main pump 2 is connected to the priority valve 8, which in turn connects to the super-lifting system 9, the telescopic cylinder 7, and the luffing cylinder 6. The multi-way valve 3 regulates the flow rate of pressurized oil in each unit of the hydraulic system.

[0023] The hydraulic principle of a large-tonnage crane using a new type of priority valve is as follows: Figure 1 As shown, it consists of a main pump 1, a main pump 2, a multi-way valve 3, a main winch 4, an auxiliary winch 5, a luffing cylinder 6, a telescopic cylinder 7, a priority valve 8, and a super-lift system 9. When the telescopic cylinder 7 and the super-lift system 9 work simultaneously, the pressure oil from the main pump 2 first reaches port P of the priority valve 8, and the pressure oil flow flows out from port A of the priority valve 8, first satisfying the flow requirements of the super-lift hydraulic system. The remaining pressure oil flow flows out from port B of the priority valve 8 and is used for the telescopic cylinder.

[0024] The control principle of the new priority valve is as follows: Figure 2As shown, when the telescopic cylinder and the super-lift system work simultaneously, pressurized oil enters from port P, passes through the hydraulic directional valve 11 to the electro-proportional directional valve 10, which provides a certain current value. The electro-proportional directional valve 10 switches, and the pressurized oil reaches the check valve 13. After passing through the check valve 13, it flows out from port A and is used for the super-lift system. The required flow rate of the super-lift system is controlled by the current value of the electro-proportional directional valve 10. After the required flow rate of the super-lift system is met, the excess flow enters from port P and switches the two-position three-way hydraulic directional valve 11. The excess flow from the two-position three-way hydraulic directional valve 11 reaches port B and is used for the telescopic cylinder.

[0025] The purpose of setting check valve 14 and damping 15 in the new priority valve is that if the hydraulic control directional valve in the priority valve is stuck or the electro-proportional directional valve does not switch, the pressure oil cannot reach port A through check valve 13. Check valve 14 and damping 15 can still supply oil to the super lift, and the super lift can still achieve emergency downward movement.

[0026] The purpose of setting the speed control valve 12 in the new priority valve is to make the switching of the electro-proportional directional valve 10 and the hydraulic directional valve 11 more stable and with less impact.

[0027] This principle is integrated into a single valve. Even if this control valve is divided into multiple valve blocks, the same objective can be achieved as long as the principle remains the same. Replacing the speed control valve with a damping network can also achieve smoother commutation and reduced impact.

[0028] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A hydraulic system for a large tonnage crane based on a new priority valve, characterized in that, The hydraulic system comprises a main pump I (1), a main pump II (2), a multi-way valve (3), a main winch (4), an auxiliary winch (5), a luffing cylinder (6), a telescopic cylinder (7), a priority valve (8), and a super-lift system (9); the main pump I (1), the main winch (4), and the auxiliary winch (5) are connected in sequence; the main pump II (2) is connected to the priority valve (8), and the priority valve (8) is connected to the super-lift system (9), the telescopic cylinder (7), and the luffing cylinder (6); the multi-way valve (3) regulates the flow rate of pressurized oil in each unit of the hydraulic system; The priority valve (8) includes an electro-proportional directional valve (10), a hydraulic directional valve (11), a speed control valve (12), a check valve I (13), a check valve II (14), and a damper (15). When the telescopic cylinder (7) and the super-lift system (9) work simultaneously, the pressure oil enters from port P, passes through the hydraulic control directional valve (11) to reach the electro-proportional directional valve (10), the electro-proportional directional valve (10) provides a certain current value, the electro-proportional directional valve (10) switches, the pressure oil reaches the check valve I (13), after passing through the check valve I (13), the pressure oil flow flows out from port A of the priority valve (8) for the super-lift system (9); after meeting the flow required by the super-lift system (9), the excess flow enters from port P, the hydraulic control directional valve (11) switches, the excess flow passes through the hydraulic control directional valve (11) to reach port B, the remaining pressure oil flow flows out from port B of the priority valve (8) for the telescopic cylinder (7). If the hydraulic directional valve (11) in the priority valve (8) is stuck or the electro-proportional directional valve (10) does not switch, the pressure oil cannot reach port A through the check valve I (13). The check valve II (14) and damper (15) are used to supply oil to the super-lift system (9), and the super-lift system (9) can still achieve emergency release. A speed control valve (12) is installed in the priority valve (8) to reduce the impact when the electro-proportional directional valve (10) and the hydraulic directional valve (11) are switched. The required flow rate of the super-start system (9) is controlled by the current value of the electro-proportional directional valve (10).

2. The hydraulic system for a large-tonnage crane based on a novel priority valve according to claim 1, characterized in that, The speed control valve (12) is replaced by a damping network.

3. The hydraulic system for a large-tonnage crane based on a novel priority valve according to claim 1, characterized in that, The super-lift system uses a single pump to regulate the flow rate, along with the telescopic, luffing, and winch systems.

4. The hydraulic system for a large-tonnage crane based on a novel priority valve according to claim 1, characterized in that, The hydraulic control directional valve (11) is a two-position three-way hydraulic control directional valve.

5. The hydraulic system for a large-tonnage crane based on a novel priority valve according to claim 1, characterized in that, The electro-proportional directional valve (10) is a two-position, two-way electro-proportional directional valve.

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