Hydraulic system and engineering machinery

Abstract

The utility model relates to a hydraulic system, in particular to a hydraulic system and engineering machinery, and the hydraulic system comprises a first hydraulic system with a priority valve, a first hydraulic pump connected with the priority valve, a second hydraulic system comprising a distribution valve, a second hydraulic pump and an expansion hydraulic system comprising an expansion reversing valve, the expansion reversing valve comprises an oil inlet valve plate, an unloading valve plate and at least one expansion reversing valve plate used for controlling the expansion hydraulic execution part. The second hydraulic pump is connected with an oil inlet of the unloading linkage valve plate, and an EF port of the priority valve is communicated with a main oil inlet path of the oil inlet linkage valve plate; according to the hydraulic system, the unloading valve can be controlled to unload the second hydraulic pump or not, single-pump oil supply or double-pump oil supply can be carried out on the expansion hydraulic system or the second hydraulic system, switching control is carried out through the switching valve plate, and working pressure oil can be provided when the expansion hydraulic system and the second hydraulic system work.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic technology, and more specifically, to a hydraulic system and engineering machinery. Background Technology

[0002] Construction machinery often uses hydraulic oil as an energy transfer medium, converting hydraulic energy into mechanical energy through hydraulic actuators to achieve various actions and functions.

[0003] Construction machinery typically has multiple hydraulic systems. For example, a loader's hydraulic system can be divided into a steering hydraulic system, a working hydraulic system, and an extension hydraulic system. The steering hydraulic system is used for vehicle steering, the working hydraulic system is used for the operation of the working device, and the extension hydraulic system is a hydraulic system equipped to perform functions other than those of the working device. The extension hydraulic system and the working hydraulic system often have a mutually exclusive relationship, that is, when the working hydraulic system is working, the extension hydraulic system is not working, and vice versa.

[0004] The hydraulic flow rate of a working hydraulic system fluctuates within a wide range during operation. High flow rates are required for rapid movements, while low flow rates are needed for delicate or slow operations. Therefore, for construction machinery, achieving both sufficient flow to meet the working hydraulic system's flow requirements and energy efficiency when expanding the hydraulic system is a key technical challenge that the industry needs to address. Utility Model Content

[0005] The technical problem to be solved by this utility model is to address the problems faced by the aforementioned hydraulic systems of engineering machinery, and to provide a hydraulic system and engineering machinery.

[0006] The technical solution of this utility model to achieve its purpose is: a hydraulic system, including a first hydraulic system with a priority valve, a first hydraulic pump connected to the priority valve, a second hydraulic system including a distribution valve, a second hydraulic pump, and an extended hydraulic system including an extended directional valve, wherein the extended directional valve includes an inlet valve plate, an unloading valve plate, and at least one extended directional valve plate for controlling the extended hydraulic actuator.

[0007] The oil inlet valve plate has a two-position three-way switching valve and a switching control valve for controlling the switching valve;

[0008] The unloading valve plate has an unloading valve, an unloading control valve for controlling the unloading valve, and an inlet and outlet oil ports that are interconnected.

[0009] Each extended directional valve plate, inlet valve plate and unloading valve plate is stacked and fixedly connected in sequence, and the return oil circuit in each valve plate is interconnected. The main inlet oil circuit in each extended directional valve plate is connected in sequence.

[0010] The second hydraulic pump is connected to the oil inlet of the unloading valve plate, the oil outlet of the unloading valve plate is connected to the main oil inlet circuit of the oil inlet valve plate which is connected to the oil inlet of the switching valve, and the oil inlet and outlet of the unloading valve are connected to the main oil inlet circuit and the oil return circuit of the unloading valve plate respectively.

[0011] The EF port of the priority valve is connected to the main oil inlet circuit of the oil inlet valve plate;

[0012] The first oil outlet of the switching valve is connected to the main oil inlet of the adjacent extended reversing valve plate, the second oil outlet of the switching valve is connected to the working oil inlet of the distribution valve, and the oil inlet of the switching valve is selectively connected to either the first oil outlet or the second oil outlet.

[0013] In the hydraulic system of this utility model, the switching control valve is a two-position three-way solenoid valve, and a pressure reducing valve is provided in the oil inlet valve plate;

[0014] The oil inlet of the pressure reducing valve is connected to the main oil inlet circuit of the oil inlet connecting valve plate, the first oil port of the switching control valve is connected to the oil outlet of the pressure reducing valve, the second oil port of the switching control valve is connected to the return oil circuit of the oil inlet connecting valve plate, the third oil port of the switching control valve is connected to the hydraulic control end of the switching valve, and the third oil port of the switching control valve can be selectively connected to either the first oil port or the third oil port.

[0015] In the hydraulic system of this utility model, an overflow valve is also provided in the oil inlet valve plate. The oil outlet of the overflow valve is connected to the oil return circuit of the oil inlet valve plate, and the oil inlet of the overflow valve is connected to the oil outlet of the pressure reducing valve.

[0016] In the hydraulic system of this invention, a first check valve is provided on the main inlet oil line of the inlet valve plate, allowing unidirectional flow from the outlet of the unloading valve plate to the main inlet oil line of the inlet valve plate. A second check valve is also provided on the main inlet oil line of the inlet valve plate, allowing unidirectional flow from the EF port of the priority valve to the main inlet oil line of the inlet valve plate.

[0017] In the hydraulic system of this utility model, a safety valve is provided in the oil inlet valve plate, and the oil inlet and outlet ports of the safety valve are connected to the oil outlet port of the switching valve and the oil return line of the oil inlet valve plate.

[0018] In the hydraulic system of this utility model, the unloading control valve is a two-position two-way solenoid valve, and its two oil ports are connected to the control chamber of the unloading valve and the return oil circuit of the unloading valve plate.

[0019] In the hydraulic system of this utility model, the unloading valve plate or the oil inlet valve plate is provided with a return oil port that is connected to the return oil circuit and connected to the hydraulic oil tank.

[0020] The technical solution of this utility model to achieve its purpose is: an engineering machine having the aforementioned hydraulic system. Optionally, the engineering machine is a loader, the first hydraulic system is a steering hydraulic system, and the second hydraulic system is a working hydraulic system.

[0021] Compared with the prior art, this utility model can control whether the second hydraulic pump is unloaded by controlling the unloading valve, so as to realize single pump oil supply or dual pump oil supply to the extended hydraulic system or the second hydraulic system. The switching control is achieved by switching valve plate, so as to provide working pressure oil when the extended hydraulic system and the second hydraulic system are working. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the hydraulic system of this utility model.

[0023] Figure 2 This is a schematic diagram of an extended directional control valve.

[0024] Component names and serial numbers in the diagram:

[0025] First hydraulic system 10, steering gear 11, steering cylinder 12.

[0026] Second hydraulic system 20, distribution valve 21, working device cylinder 22.

[0027] Expand the hydraulic system 30, expand the directional valve 31, and expand the hydraulic actuator 32.

[0028] First hydraulic pump 40, second hydraulic pump 50.

[0029] Extended reversing valve plate 311, oil inlet valve plate 312, and unloading valve plate 313.

[0030] Extend the main oil inlet circuit of the directional valve plate 51, extend the return oil circuit of the directional valve plate 52, switch valve 53, switch control valve 54, main oil inlet circuit of the inlet coupling valve plate 55, return oil circuit of the inlet coupling valve plate 56, pressure reducing valve 57, relief valve 58, first check valve 59, second check valve 60, safety valve 61, unloading valve 62, unloading control valve 63, return oil circuit of the unloading coupling valve plate 64, main oil inlet circuit of the unloading coupling valve plate 65. Detailed Implementation

[0031] The specific implementation plan is described below with reference to the attached diagram.

[0032] like Figure 1 Figure 2As shown, the hydraulic system includes a first hydraulic system 10 with a priority valve, a first hydraulic pump 40 connected to the priority valve, a second hydraulic system 20 including a distribution valve, a second hydraulic pump 50, and an extended hydraulic system 30 including an extended directional valve 31. The extended directional valve 31 includes an inlet valve plate 312, an unloading valve plate 313, and at least one extended directional valve plate 311 for controlling the extended hydraulic actuator 32.

[0033] The inlet valve plate 312 has a switching valve 53 and a switching control valve 54 for controlling the switching valve 53. The unloading valve plate 313 has an unloading valve 62, an unloading control valve 63 for controlling the unloading valve 62, and interconnected inlet and outlet ports.

[0034] like Figure 1 As shown, the extended directional valve plate 311, the inlet valve plate 312, and the unloading valve plate 313 are stacked in sequence and fixed together with bolts. Each extended directional valve plate 311, the inlet valve plate 312, and the unloading valve plate 313 is provided with a main oil inlet passage and an oil return passage.

[0035] The return oil passages of each valve plate in the extended directional valve 31 are interconnected, and the main inlet oil passages 51 of each extended directional valve plate 311 are sequentially connected. The second hydraulic pump 50 is connected to the inlet (P port) of the unloading coupling valve plate 313, and the outlet of the unloading coupling valve plate is connected to the main inlet oil passage 55 of the inlet coupling valve plate 312, which connects to the inlet of the switching valve 53. The inlet and outlet ports of the unloading valve 62 are connected to the main inlet oil passage 65 and the return oil passage of the unloading coupling valve plate, respectively. The connecting oil passage between the outlet of the unloading coupling valve plate and the inlet of the unloading coupling valve plate 313 is the main inlet oil passage 65 of the unloading coupling valve plate.

[0036] The unloading valve plate is equipped with a return oil port connected to the return oil circuit. This return oil port is connected to the hydraulic oil tank to realize the return oil of the hydraulic system. Alternatively, the return oil port can also be set on the inlet valve plate and connected to the return oil circuit, so that the return oil of the hydraulic system is led from the inlet valve plate to the hydraulic oil tank through the pipeline.

[0037] The EF port of the priority valve (not shown in the figure) is connected to the main oil inlet circuit 55 of the oil inlet valve plate. For example... Figure 2 As shown, the inlet valve plate 312 is arranged between the extended directional valve plate 311 and the unloading valve plate 313. The two ends of the inlet valve plate return oil passage 56 are respectively connected to the extended directional valve plate return oil passage 52 and the unloading valve plate return oil passage 64. The switching valve 53 is a two-position three-way hydraulic valve. The first oil outlet of the switching valve 53 is connected to the main inlet oil passage 51 of the adjacent extended directional valve plate, and the second oil outlet of the switching valve 53 is connected to the working oil inlet of the distribution valve 21. The oil inlet of the switching valve 53 can be selectively connected to either the first oil outlet or the second oil outlet.

[0038] The switching control valve 54 is a two-position three-way solenoid valve. A pressure reducing valve 57 and a relief valve 58 are provided in the inlet valve plate 312. The inlet of the pressure reducing valve 57 is connected to the main inlet oil passage 55 of the inlet valve plate. The first port of the switching control valve 54 is connected to the outlet of the pressure reducing valve 57. The second port of the switching control valve 54 is connected to the return oil passage 56 of the inlet valve plate. The third port of the switching control valve 54 is connected to the hydraulic control end of the switching valve 53. The third port of the switching control valve 54 can be selectively connected to either the first port or the third port.

[0039] The outlet of the relief valve 58 is connected to the return oil circuit 56 of the inlet valve plate, and the inlet of the relief valve 58 is connected to the outlet of the pressure reducing valve. The pressure reducing valve 57 provides a pressure oil source for the switching valve 53 to control the reversing, while the relief valve 58 plays a protective role, preventing the pressure at the first oil port of the switching control valve 54 from being too high.

[0040] Optionally, a first check valve 59 is provided on the main inlet oil passage 55 of the inlet valve plate, allowing unidirectional flow from the outlet of the unloading valve plate 313 to the main inlet oil passage 55. A second check valve 60 is provided on the main inlet oil passage 55, allowing unidirectional flow from the EF port of the priority valve to the main inlet oil passage 55. When the unloading valve 62 is opened for unloading, the first check valve 59 prevents high-pressure oil from flowing from the inlet of the switching valve 53 to the unloading valve 62. The second check valve 60 prevents high-pressure oil from flowing from the inlet of the switching valve 53 to the priority valve.

[0041] Optionally, a safety valve 61 is provided in the oil inlet valve plate 312, and the two oil ports of the safety valve 61 are connected to the oil outlet of the switching valve 53 and the oil return line of the oil inlet valve plate.

[0042] Optionally, the unloading control valve 63 is a two-position, two-way solenoid valve, with its two ports connected to the control chamber of the unloading valve 62 and the return oil passage 64 of the unloading interlock valve plate. When the unloading control valve 63 is open, the control chamber of the unloading valve 62 is connected to the return oil passage 64 of the unloading interlock valve plate via the unloading control valve 63, causing the unloading valve 62 to open. When the unloading control valve 63 is closed, the control chamber of the unloading valve 62 is filled with fluid, causing the unloading valve 62 to close.

[0043] In this embodiment, the switching valve 53 switches the pressure oil source between the extended hydraulic system 30 and the second hydraulic system 20. When the extended hydraulic system 30 is operating, the switching valve 53 connects its inlet to the first outlet, supplying pressure oil from the first hydraulic system 10 and the unloading valve plate 313 to the extended hydraulic system 30. When the second hydraulic system 20 is operating, the switching valve 53 connects its inlet to the second outlet, supplying pressure oil from the first hydraulic system 10 and the unloading valve plate 313 to the second hydraulic system 20. When the expansion hydraulic system 30 or the second hydraulic system 20 requires a large flow rate, the unloading control valve 63 controls the unloading valve 62 to close, and the pressure oil from the first hydraulic pump 40 and the second hydraulic pump 50 flows to the expansion hydraulic system 30 or the second hydraulic system 20 through the combined inlet flow. When the expansion hydraulic system 30 or the second hydraulic system 20 requires a small flow rate, the unloading control valve 63 controls the unloading valve 62 to open, and the pressure oil from the second hydraulic pump 50 is unloaded through the unloading valve plate 313, and the second hydraulic system 20 is only supplied with oil by the first hydraulic pump 40.

[0044] The first hydraulic pump 40 supplies oil to the first hydraulic system 10 via a priority valve (not shown in the figure), and its excess flow flows to the inlet valve plate 312 via the priority valve to supply the extended hydraulic system 30 or the second hydraulic system 20.

[0045] This embodiment also provides an engineering machine having the aforementioned hydraulic system. Optionally, the engineering machine is a loader, the first hydraulic system is a steering hydraulic system, and the second hydraulic system is a working hydraulic system.

[0046] In the first hydraulic system 10, the steering gear 11 controls the extension and retraction of the steering cylinder 12 to enable the loader to perform steering. The steering gear 11 is equipped with a priority valve. The pressure oil from the first hydraulic pump is supplied to the first hydraulic system 10 via the priority valve. The excess flow flows from the EF port of the priority valve to the oil inlet valve plate of the extended directional valve 31, and merges with the pressure oil from the second hydraulic pump to supply the extended hydraulic system or the loader working hydraulic system.

Claims

1. A hydraulic system comprising a first hydraulic system having a priority valve, a first hydraulic pump connected to the priority valve, a second hydraulic system including a distribution valve, the second hydraulic pump, and an extended hydraulic system including an extended directional valve, characterized in that, The extended directional valve includes an inlet valve plate, an unloading valve plate, and at least one extended directional valve plate for controlling the extended hydraulic actuator. The oil inlet valve plate has a two-position three-way switching valve and a switching control valve for controlling the switching valve; The unloading valve plate has an unloading valve, an unloading control valve for controlling the unloading valve, and an inlet and outlet oil ports that are interconnected. Each extended directional valve plate, inlet valve plate and unloading valve plate is stacked and fixedly connected in sequence, and the return oil circuit in each valve plate is interconnected. The main inlet oil circuit in each extended directional valve plate is connected in sequence. The second hydraulic pump is connected to the oil inlet of the unloading valve plate, the oil outlet of the unloading valve plate is connected to the main oil inlet circuit of the oil inlet valve plate which is connected to the oil inlet of the switching valve, and the oil inlet and outlet of the unloading valve are connected to the main oil inlet circuit and the oil return circuit of the unloading valve plate respectively. The EF port of the priority valve is connected to the main oil inlet circuit of the oil inlet valve plate; The first oil outlet of the switching valve is connected to the main oil inlet of the adjacent extended reversing valve plate, the second oil outlet of the switching valve is connected to the working oil inlet of the distribution valve, and the oil inlet of the switching valve is selectively connected to either the first oil outlet or the second oil outlet.

2. The hydraulic system according to claim 1, characterized in that, The switching control valve is a two-position three-way solenoid valve, and a pressure reducing valve is provided in the oil inlet valve plate; The oil inlet of the pressure reducing valve is connected to the main oil inlet circuit of the oil inlet connecting valve plate, the first oil port of the switching control valve is connected to the oil outlet of the pressure reducing valve, the second oil port of the switching control valve is connected to the return oil circuit of the oil inlet connecting valve plate, the third oil port of the switching control valve is connected to the hydraulic control end of the switching valve, and the third oil port of the switching control valve can be selectively connected to either the first oil port or the third oil port.

3. The hydraulic system according to claim 2, characterized in that, The inlet valve plate is also equipped with an overflow valve. The outlet of the overflow valve is connected to the return oil circuit of the inlet valve plate, and the inlet of the overflow valve is connected to the outlet of the pressure reducing valve.

4. The hydraulic system according to any one of claims 1 to 3, characterized in that, The main oil inlet line of the oil inlet valve plate is equipped with a first one-way valve that allows unidirectional flow from the oil outlet of the unloading valve plate to the main oil inlet line of the oil inlet valve plate.

5. The hydraulic system according to claim 4, characterized in that, The main oil inlet line of the oil inlet valve plate is equipped with a second one-way valve that allows unidirectional flow from the EF port of the priority valve to the main oil inlet line of the oil inlet valve plate.

6. The hydraulic system according to claim 5, characterized in that, The inlet valve plate is equipped with a safety valve, and the inlet and outlet ports of the safety valve are connected to the outlet port of the switching valve and the return oil circuit of the inlet valve plate.

7. The hydraulic system according to claim 1, characterized in that, The unloading control valve is a two-position two-way solenoid valve, and its two oil ports are connected to the control chamber of the unloading valve and the return oil circuit of the unloading valve plate.

8. The hydraulic system according to claim 1, characterized in that, The unloading valve plate or the oil inlet valve plate is provided with an oil return port that is connected to the oil return circuit and the hydraulic oil tank.

9. An engineering machinery, characterized in that, A hydraulic system having any one of claims 1 to 8.

10. The engineering machinery according to claim 9, characterized in that, The construction machinery is a loader, the first hydraulic system is a steering hydraulic system, and the second hydraulic system is a working hydraulic system.

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