Hydraulic control system of loading machine

Abstract

The invention belongs to the technical field of loaders, and discloses a hydraulic control system of a loader, which comprises an oil tank, a working pump, a steering pump, a working valve group, an energy accumulator, an unloading valve group, a first control valve group, a second control valve group and a third control valve group, the working valve set is provided with an oil port P0 communicating with the movable arm reversing valve and the bucket reversing valve, the working pump communicates with the oil port P0, the unloading valve set is used for unloading the working pump, and the energy accumulator can be connected and disconnected with the hydraulic control end e1 and the hydraulic control end e2 of the movable arm reversing valve and the hydraulic control end e3 and the hydraulic control end e4 of the bucket reversing valve through the first control valve set. The energy accumulator can be connected and disconnected with the unloading valve set through the second control valve set, the energy accumulator can open the unloading valve set, and the steering pump can be connected and disconnected with the oil port P0 through the third control valve set. According to the system, on-demand work of the working pump and the steering pump can be achieved, system power is distributed in sequence, the electric control degree of the system is high, and the system is more energy-saving.

Description

Technical Field

[0001] The present invention relates to the technical field of loaders, and in particular to a hydraulic control system of a loader. Background Art

[0002] At present, a single variable hydraulic system of a loader is provided with a working pump and a steering pump at the same time. Specifically, the working pump is a gear pump, and the steering pump is a plunger pump, and the plunger pump generally uses a load sensing control and a pressure compensation control method.

[0003] In the prior art, the loader hydraulic control system generally has two working modes, namely, when the boom reversing valve and / or the bucket steering valve are in action, the steering pump merges with the working pump, and when the boom reversing valve and / or the bucket steering valve are not in action, the steering pump only supplies oil to the steering system. However, there are many requirements in actual work. For example, when the boom is lowered, the working pump and the steering pump do not need to supply oil. When the bucket is retracted or tipped, only the steering pump needs to supply oil to the working system and the working pump is unloaded, etc. The current system cannot achieve on-demand distribution. Summary of the invention

[0004] The object of the present invention is to provide a loader hydraulic control system, which can realize the on-demand operation of a working pump and a steering pump, realize the sequential distribution of the power of the entire hydraulic system, the system has a high degree of electronic control, and the system is more energy-efficient.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A loader hydraulic control system includes an oil tank, a working pump, a steering pump, a working valve group, an accumulator, an unloading valve group, a first control valve group, a second control valve group and a third control valve group; wherein,

[0007] The oil inlets of the working pump and the steering pump are connected to the oil tank;

[0008] The working valve group includes a boom reversing valve and a bucket reversing valve, the boom reversing valve has a hydraulic control end e1 and a hydraulic control end e2, the bucket reversing valve has a hydraulic control end e3 and a hydraulic control end e4, and the working valve group has an oil port P0, the oil port P0 is connected to the oil inlet of the boom reversing valve and the bucket reversing valve;

[0009] The working pump is connected to the oil port P0, and the unloading valve group is arranged on the connecting pipeline between the oil outlet of the working pump and the oil port P0, and the unloading valve group is used to unload the working pump;

[0010] The accumulator can be connected or disconnected with the hydraulic control end e1, the hydraulic control end e2, the hydraulic control end e3 and the hydraulic control end e4 respectively through the first control valve group;

[0011] The accumulator can be connected or disconnected with the unloading valve group through the second control valve group, and the unloading valve group can be opened when the accumulator is connected with the unloading valve group;

[0012] The steering pump can be connected to or disconnected from the oil port P0 through the third control valve group.

[0013] Preferably, the unloading valve group includes an unloading reversing valve and a relief valve, the oil outlet of the working pump is connected to the oil inlet of the unloading reversing valve and the oil inlet of the relief valve, the oil outlet of the unloading reversing valve is connected to the oil tank, and the oil outlet of the relief valve is connected to the hydraulic control end e5 of the unloading reversing valve and the oil tank;

[0014] The accumulator can be connected to or disconnected from the oil outlet of the unloading reversing valve through the second control valve group.

[0015] Preferably, the unloading valve group further comprises a first one-way valve, and the first one-way valve is configured to conduct the hydraulic oil in one direction from the oil inlet of the unloading reversing valve to the oil inlet of the overflow valve.

[0016] Preferably, the first control valve group includes a first hydraulic-controlled-end reversing valve, a second hydraulic-controlled-end reversing valve, a third hydraulic-controlled-end reversing valve and a fourth hydraulic-controlled-end reversing valve, the accumulator is connected to the oil inlets of the first hydraulic-controlled-end reversing valve, the second hydraulic-controlled-end reversing valve, the third hydraulic-controlled-end reversing valve and the fourth hydraulic-controlled-end reversing valve, respectively, the oil outlet of the first hydraulic-controlled-end reversing valve is connected to the hydraulic-controlled end e1, the oil outlet of the second hydraulic-controlled-end reversing valve is connected to the hydraulic-controlled end e2, the oil outlet of the third hydraulic-controlled-end reversing valve is connected to the hydraulic-controlled end e3, and the oil outlet of the fourth hydraulic-controlled-end reversing valve is connected to the hydraulic-controlled end e4.

[0017] Preferably, the first hydraulic-controlled-end reversing valve, the second hydraulic-controlled-end reversing valve, the third hydraulic-controlled-end reversing valve and the fourth hydraulic-controlled-end reversing valve are all configured as electromagnetic reversing valves.

[0018] Preferably, a pressure reducing valve is also included, the accumulator is connected to the oil inlet of the pressure reducing valve, and the oil outlet of the pressure reducing valve is respectively connected to the oil inlets of the first hydraulic-controlled end reversing valve, the second hydraulic-controlled end reversing valve, the third hydraulic-controlled end reversing valve and the fourth hydraulic-controlled end reversing valve.

[0019] Preferably, the second control valve group includes a first control reversing valve and a second control reversing valve, and the third control valve group includes a third control reversing valve; wherein,

[0020] The accumulator is connected to the oil inlet of the first control reversing valve and the oil inlet of the second control reversing valve, the oil outlet of the first control reversing valve is connected to the hydraulic control end e6 of the third control reversing valve, the oil outlet of the second control reversing valve is connected to the unloading valve group, the oil outlet of the steering pump is connected to the oil inlet of the third control reversing valve, and the oil outlet of the third control reversing valve is connected to the oil port P0.

[0021] Preferably, the invention further comprises a steering gear and a flow amplification valve, wherein the steering pump is configured as a plunger pump, the oil outlet of the steering pump is connected to the steering gear and the flow amplification valve, the steering gear has a first feedback oil port, and the flow amplification valve has a second feedback oil port;

[0022] The third control valve group also includes a shuttle valve, the working oil port B1 of the shuttle valve is connected to the oil outlet of the third control reversing valve, the working oil port B2 of the shuttle valve is connected to the first feedback oil port and the second feedback oil port, and the working oil port B3 of the shuttle valve is connected to the third feedback oil port of the steering pump, and the displacement of the steering pump is adjusted according to the pressure of the third feedback oil port.

[0023] Preferably, a second one-way valve is provided between the working oil port B3 of the shuttle valve and the third feedback oil port, and the second one-way valve is configured to conduct hydraulic oil in a unidirectional direction from the working oil port B3 to the third feedback oil port.

[0024] Preferably, the first control reversing valve and the second control reversing valve are both configured as electromagnetic reversing valves.

[0025] Beneficial effects:

[0026] The loader hydraulic control system provided by the present invention can realize the on-demand operation of the working pump and the steering pump through the coordinated control of the unloading valve group, the first control valve group, the second control valve group and the third control valve group, and control the reversing action of the boom reversing valve and the bucket reversing valve through the first control valve group, thereby realizing the corresponding control of the lifting and lowering of the loader boom and the folding of the bucket. The unloading valve group is used to control whether the working pump is unloaded; the second control valve group is used to control whether the pilot oil of the accumulator controls the opening of the unloading valve group; the third control valve group is used to control whether the steering pump is connected to the oil port P0, that is, to control whether the steering pump merges with the working pump. The working pump and the steering pump work on demand, thereby realizing the on-demand distribution of the power of the entire hydraulic system, the system has a high degree of electronic control, and the system is more energy-saving. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of a loader hydraulic control system provided by the present invention;

[0028] Figure 2 It is a schematic diagram of the unloading valve group provided by the present invention;

[0029] Figure 3 It is a schematic diagram of the working valve group and the first control valve group provided by the present invention;

[0030] Figure 4 It is a schematic diagram of the second control valve group and the third control valve group provided by the present invention.

[0031] In the figure:

[0032] 1. Fuel tank;

[0033] 21. Working pump; 22. Steering pump;

[0034] 31. Boom reversing valve; 32. Bucket reversing valve; 33. Boom cylinder; 34. Bucket cylinder;

[0035] 4. Accumulator;

[0036] 51. Unloading reversing valve; 52. Overflow valve; 53. First check valve;

[0037] 61, first hydraulic control end reversing valve; 62, second hydraulic control end reversing valve; 63, third hydraulic control end reversing valve; 64, fourth hydraulic control end reversing valve;

[0038] 71. A first control reversing valve; 72. A second control reversing valve;

[0039] 81. The third control reversing valve; 82. The shuttle valve; 83. The second check valve;

[0040] 9. Steering gear;

[0041] 10. Flow amplification valve;

[0042] 11. Pressure reducing valve;

[0043] 12. Braking system;

[0044] 13. Controller; 131. Electric control handle. DETAILED DESCRIPTION

[0045] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0046] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0048] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0049] This embodiment provides a loader hydraulic control system. Figures 1 to 4As shown, the loader hydraulic control system includes an oil tank 1, a working pump 21, a steering pump 22, a working valve group, an accumulator 4, an unloading valve group, a first control valve group, a second control valve group and a third control valve group. Among them, the oil inlets of the working pump 21 and the steering pump 22 are connected to the oil tank 1; the working valve group includes a boom reversing valve 31 and a bucket reversing valve 32, the boom reversing valve 31 has a hydraulic control end e1 and a hydraulic control end e2, the bucket reversing valve 32 has a hydraulic control end e3 and a hydraulic control end e4, the working valve group has an oil port P0, and the oil port P0 is connected to the oil inlet of the boom reversing valve 31 and the bucket reversing valve 32; the working pump 21 is connected to the oil port P0, and the unloading valve group is provided between the oil outlet of the working pump 21 and the oil outlet of the working pump 21. On the connecting pipeline between the oil port P0, the unloading valve group is used to unload the working pump 21; the accumulator 4 can be connected or disconnected with the hydraulic control end e1, the hydraulic control end e2, the hydraulic control end e3 and the hydraulic control end e4 respectively through the first control valve group; the accumulator 4 can be connected or disconnected with the unloading valve group through the second control valve group, and the unloading valve group can be opened when the accumulator 4 is connected to the unloading valve group; the steering pump 22 can be connected or disconnected with the oil port P0 through the third control valve group.

[0050] Specifically, the two working oil ports of the boom reversing valve 31 are connected to the boom cylinder 33, and the return oil port of the boom reversing valve 31 is connected to the oil tank 1. The boom cylinder 33 is connected to the boom of the loader. The boom reversing valve 31 has a neutral position, a lifting position, a lowering position and a floating position. When the lifting position of the boom reversing valve 31 is in the working position, the hydraulic oil can drive the cylinder rod of the boom cylinder 33 to extend through the boom reversing valve 31, thereby realizing the lifting of the boom; when the lowering position of the boom reversing valve 31 is in the working position, the hydraulic oil can drive the cylinder rod of the boom cylinder 33 to retract through the boom reversing valve 31, thereby realizing the lowering of the boom; when the floating position of the boom reversing valve 31 is in the working position, the boom cylinder 33 remains in a floating state, that is, the floating of the boom is realized.

[0051] Specifically, the two working oil ports of the bucket reversing valve 32 are connected to the bucket cylinder 34, and the return oil port of the bucket reversing valve 32 is connected to the oil tank 1. The bucket cylinder 34 is connected to the bucket of the loader. The bucket reversing valve 32 has a middle position, a bucket tipping position, and a bucket collection position. When the bucket collection position of the bucket reversing valve 32 is in the working position, the hydraulic oil can drive the cylinder rod of the bucket cylinder 34 to extend outward through the bucket reversing valve 32, thereby realizing the bucket collection; when the bucket tipping position of the bucket reversing valve 32 is in the working position, the hydraulic oil can drive the cylinder rod of the bucket cylinder 34 to retract through the bucket reversing valve 32, thereby realizing the bucket tipping and unloading.

[0052] Specifically, the accumulator 4 is a brake accumulator 4, which is connected to the brake system 12 of the loader. The accumulator 4 can store the hydraulic oil in the brake system 12 to be used as the pilot oil of the hydraulic control system. The accumulator 4 can be connected or disconnected with the hydraulic control end e1, the hydraulic control end e2, the hydraulic control end e3 and the hydraulic control end e4 respectively through the first control valve group. Exemplarily, the first control valve group controls the accumulator 4 to connect with the hydraulic control end e1, and the hydraulic oil output in the accumulator 4 can be delivered to the hydraulic control end e1, so that the valve core of the lifting control valve moves left to the lifting position and is in the working position. The first control valve group controls the accumulator 4 to connect with the hydraulic control end e2, and the hydraulic oil output in the accumulator 4 can be delivered to the hydraulic control end e2, so that the valve core of the lifting control valve moves right to the lowering position and is in the working position. In addition, the hydraulic oil output in the accumulator 4 can be further delivered to the hydraulic control end e2, so that the valve core of the lifting control valve moves right to the floating position and is in the working position. The first control valve group controls the accumulator 4 to communicate with the hydraulic control end e3, and the hydraulic oil output in the accumulator 4 can be delivered to the hydraulic control end e3, so that the valve core of the bucket control valve moves left to the bucket retracting position in the working position. The first control valve group controls the accumulator 4 to communicate with the hydraulic control end e4, and the hydraulic oil output in the accumulator 4 can be delivered to the hydraulic control end e4, so that the valve core of the bucket control valve moves right to the bucket dumping position in the working position.

[0053] In this embodiment, the loader hydraulic control system further includes a pressure reducing valve 11, the accumulator 4 is connected to the oil inlet of the pressure reducing valve 11, and the oil outlet of the pressure reducing valve 11 is connected or disconnected with the hydraulic control end e1, the hydraulic control end e2, the hydraulic control end e3 and the hydraulic control end e4 through the first control valve group. By providing the pressure reducing valve 11, the high-pressure oil in the accumulator 4 can be reduced to a certain pressure value and then transported as a pilot oil.

[0054] In this embodiment, the unloading valve group includes an unloading reversing valve 51 and a relief valve 52. The oil outlet of the working pump 21 is connected to the oil inlet of the unloading reversing valve 51 and the oil inlet of the relief valve 52. The oil outlet of the unloading reversing valve 51 is connected to the oil tank 1. The oil outlet of the relief valve 52 is connected to the hydraulic control end e5 of the unloading reversing valve 51 and the oil tank 1. Specifically, the working pump 21 pumps hydraulic oil from the oil tank 1. When the hydraulic oil pressure does not reach the unloading threshold, the unloading reversing valve 51 and the relief valve 52 are both in the cut-off state. At this time, the hydraulic oil directly passes through the oil port P0 and is delivered to the working valve group. When the hydraulic oil pressure reaches the unloading threshold, the hydraulic oil flows to the hydraulic control end of the relief valve 52, pushing the relief valve 52 to change direction and conduct, so that the hydraulic oil can reach the hydraulic control end e5 of the unloading reversing valve 51, pushing the unloading reversing valve 51 to change direction and conduct, so that the hydraulic oil can flow back to the oil tank 1 through the unloading reversing valve 51, thereby unloading the working pump 21. In addition, the accumulator 4 can be connected or disconnected with the oil outlet of the unloading reversing valve 51 through the second control valve group. When the accumulator 4 is connected to the oil outlet of the unloading reversing valve 51 through the second control valve group, the working pump can also be unloaded.

[0055] In this embodiment, the unloading valve group further includes a first one-way valve 53, which is configured to conduct the hydraulic oil in one direction from the oil inlet of the unloading reversing valve 51 to the oil inlet of the relief valve 52. By providing the first one-way valve 53, the oil path between the oil inlet of the unloading reversing valve 51 and the oil inlet of the relief valve 52 can be guided and conducted, so as to prevent the hydraulic oil outputted by the working pump 21 from flowing back toward the unloading reversing valve 51, thereby preventing the entire hydraulic system from being unloaded, and effectively protecting the working pump 21.

[0056] In this embodiment, the first control valve group includes a first hydraulic-controlled-end reversing valve 61, a second hydraulic-controlled-end reversing valve 62, a third hydraulic-controlled-end reversing valve 63 and a fourth hydraulic-controlled-end reversing valve 64. The accumulator 4 is connected to the oil inlets of the first hydraulic-controlled-end reversing valve 61, the second hydraulic-controlled-end reversing valve 62, the third hydraulic-controlled-end reversing valve 63 and the fourth hydraulic-controlled-end reversing valve 64 respectively. The oil outlet of the first hydraulic-controlled-end reversing valve 61 is connected to the hydraulic-controlled end e1, the oil outlet of the second hydraulic-controlled-end reversing valve 62 is connected to the hydraulic-controlled end e2, the oil outlet of the third hydraulic-controlled-end reversing valve 63 is connected to the hydraulic-controlled end e3, and the oil outlet of the fourth hydraulic-controlled-end reversing valve 64 is connected to the hydraulic-controlled end e4. Specifically, when the first hydraulically controlled reversing valve 61 is turned on and the second hydraulically controlled reversing valve is turned off, the hydraulic oil of the accumulator 4 can reach the hydraulically controlled end e1 of the boom reversing valve 31 through the first pressure-controlled reversing valve, thereby pushing the valve core of the boom reversing valve 31 to move left, so that the boom reversing valve 31 can be switched to the lifting position; when the first hydraulically controlled reversing valve 61 is turned off and the second hydraulically controlled reversing valve is turned on, the hydraulic oil of the accumulator 4 can reach the hydraulically controlled end e2 of the boom reversing valve 31 through the second pressure-controlled reversing valve, thereby pushing the valve core of the boom reversing valve 31 to move right, so that the boom reversing valve 31 can be switched to the lowering position or the floating position. When the third hydraulic-controlled end reversing valve 63 is turned on and the fourth hydraulic-controlled reversing valve is turned off, the hydraulic oil of the accumulator 4 can reach the hydraulic-controlled end e3 of the bucket reversing valve 32 through the third pressure-controlled reversing valve, thereby pushing the valve core of the bucket reversing valve 32 to move left, so that the bucket reversing valve 32 can be switched to the bucket-retracting position; when the third hydraulic-controlled end reversing valve 63 is turned off and the fourth hydraulic-controlled reversing valve is turned on, the hydraulic oil of the accumulator 4 can reach the hydraulic-controlled end e4 of the bucket reversing valve 32 through the fourth pressure-controlled reversing valve, thereby pushing the valve core of the bucket reversing valve 32 to move right, so that the bucket reversing valve 32 can be switched to the bucket-turning position.

[0057] Exemplarily, the first hydraulic-controlled reversing valve 61, the second hydraulic-controlled reversing valve 62, the third hydraulic-controlled reversing valve 63 and the fourth hydraulic-controlled reversing valve 64 are all configured as electromagnetic reversing valves. Specifically, the loader hydraulic control system further comprises a controller 13, the operating end of the controller 13 is communicatively connected with an electric control handle 131, and the controller 13 is communicatively connected with the first hydraulic-controlled reversing valve 61, the second hydraulic-controlled reversing valve 62, the third hydraulic-controlled reversing valve 63 and the fourth hydraulic-controlled reversing valve 64 respectively. The control instructions are issued by operating the electric control handle 131, and then the electromagnets corresponding to the first hydraulic-controlled reversing valve 61, the second hydraulic-controlled reversing valve 62, the third hydraulic-controlled reversing valve 63 and the fourth hydraulic-controlled reversing valve 64 are energized by the controller 13, thereby realizing fast and reliable reversing control of the first hydraulic-controlled reversing valve 61, the second hydraulic-controlled reversing valve 62, the third hydraulic-controlled reversing valve 63 and the fourth hydraulic-controlled reversing valve 64.

[0058] In this embodiment, the second control valve group includes a first control reversing valve 71 and a second control reversing valve 72 , and the third control valve group includes a third control reversing valve 81 .

[0059] The accumulator 4 is connected to the oil inlet of the first control reversing valve 71 and the oil inlet of the second control reversing valve 72, the oil outlet of the first control reversing valve 71 is connected to the hydraulic control end e6 of the third control reversing valve 81, the oil outlet of the second control reversing valve 72 is connected to the unloading valve group, the oil outlet of the steering pump 22 is connected to the oil inlet of the third control reversing valve 81, and the oil outlet of the third control reversing valve 81 is connected to the oil port P0. Specifically, the first control reversing valve 71 is provided to realize the on-off of the pilot oil and the second control valve group, that is, the third control reversing valve 81. Specifically, when the first control reversing valve 71 is turned on, the pilot oil reaches the hydraulic control end e6 of the third control reversing valve 81 through the first control reversing valve 71, pushing the third control reversing valve 81 to change direction, and connecting the oil outlet of the steering pump 22 and the oil port P0, so that the steering pump 22 can take hydraulic oil from the oil tank 1 to the oil port P0, thereby realizing the confluence of the steering pump 22 and the working pump 21. Specifically, the second control reversing valve 72 is set to realize the on-off of the hydraulic oil of the accumulator 4 and the unloading valve group. Specifically, the oil outlet of the second control reversing valve 72 is connected to the hydraulic control end e5 of the unloading reversing valve 51. When the second control reversing valve 72 is turned on, the hydraulic oil in the accumulator 4 can reach the hydraulic control end e5 of the unloading reversing valve 51 through the second control reversing valve 72 to push the unloading reversing valve 51 to change to conduction, so that the hydraulic oil of the working pump 21 can be unloaded.

[0060] For example, the first control reversing valve 71 and the second control reversing valve 72 are both configured as electromagnetic reversing valves. Specifically, the controller 13 is in communication connection with the first control reversing valve 71 and the second control reversing valve 72. The control command is issued by the electric control handle 131, and then the electromagnets corresponding to the first control reversing valve 71 and the second control reversing valve 72 are energized by the controller 13, thereby realizing fast and reliable reversing control of the first control reversing valve 71 and the second control reversing valve 72.

[0061] In this embodiment, the loader hydraulic control system further includes a steering gear 9 and a flow amplification valve 10, the steering pump 22 is configured as a plunger pump, the oil outlet of the steering pump 22 is connected to the steering gear 9 and the flow amplification valve 10, the steering gear 9 has a first feedback oil port, and the flow amplification valve 10 has a second feedback oil port. The third control valve group further includes a shuttle valve 82, the working oil port B1 of the shuttle valve 82 is connected to the oil outlet of the third control reversing valve 81, the working oil port B2 of the shuttle valve 82 is connected to the first feedback oil port and the second feedback oil port, and the working oil port B3 of the shuttle valve 82 is connected to the third feedback oil port of the steering pump 22, and the displacement of the steering pump 22 is adjusted according to the pressure of the third feedback oil port. Specifically, the Ls signal of the flow amplification valve 10 and the Ls signal of the steering gear 9 are connected in series to be referred to as the Ls signal of the steering system. When the whole machine is only steering, the hydraulic oil in the steering gear 9 is fed back to the third feedback oil port of the steering pump 22 through the oil ports B2 and B3 of the shuttle valve 82 in sequence to control the displacement change of the pump. When the working valve group of the whole machine is working, that is, the boom is lifted, lowered, the bucket is retracted, and the bucket is tipped, the hydraulic oil delivered by the working pump 21 is fed back to the third feedback oil port of the steering pump 22 through the oil port B1 and the oil port B3 of the shuttle valve 82 in sequence, and the steering pump 22 works at the maximum displacement. The principle and process of adjusting the displacement of the plunger pump are prior art and are not the focus of this application, so no further elaboration is made here.

[0062] In this embodiment, a second one-way valve 83 is provided between the working oil port B3 and the third feedback oil port of the shuttle valve 82, and the second one-way valve 83 is configured to conduct the hydraulic oil in a one-way direction from the working oil port B3 to the third feedback oil port. By providing the second one-way valve 83, it is possible to prevent the hydraulic oil in the third feedback oil port from flowing back to the shuttle valve 82, thereby ensuring the reliability and effectiveness of the one-way flow of this part of the hydraulic oil.

[0063] By way of example, the working conditions of the valve group and the oil circuit transportation conditions corresponding to several different working conditions of the loader using the hydraulic control system are described below.

[0064] When the whole machine is started, the boom and bucket do not move, that is, the working valve group does not work, and the electric control handle 131 does not move. The first hydraulic control end reversing valve 61, the second hydraulic control end reversing valve 62, the third hydraulic control end reversing valve 63 and the fourth hydraulic control end reversing valve 64 are all in the middle position, no pilot oil enters, and the valve cores of the boom reversing valve 31 and the bucket reversing valve 32 are in the middle position. The hydraulic oil pumped by the working pump 21 passes through the unloading reversing valve 51 ， After passing through the middle position of the working valve, it returns to the oil tank 1. Since there is no hydraulic oil at the hydraulic control end e6 of the third control reversing valve 81 at this time, the third control reversing valve 81 does not change direction, and there is no conduction between the steering pump 22 and the oil port P0. Therefore, the steering pump 22 only adjusts the displacement of the steering pump 22 according to the feedback of the steering system Ls signal to supply oil to the steering gear 9.

[0065] When the boom is lifted, the working pump 21 and the steering pump 22 need to merge to supply oil to the boom reversing valve 31 of the working valve group. The electric control handle 131 communicates with the controller 13, and the controller 13 sends a current signal to the first hydraulically controlled reversing valve 61 and the first control reversing valve 71, so that the first hydraulically controlled reversing valve 61 and the first control reversing valve 71 are reversed. Specifically, the first hydraulically controlled reversing valve 61 reverses the oil circuit from the accumulator 4 to the hydraulically controlled end e1 of the boom reversing valve 31. A pilot oil flow route is: accumulator 4, pressure reducing valve 11, first hydraulically controlled reversing valve 61, hydraulically controlled end e1 of the boom reversing valve 31, pushing the boom reversing valve 31 to reverse, and the boom reversing valve 31 moves left to move the valve core to the lifting position. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, first control reversing valve 71, hydraulic control end e6 of third control reversing valve 81, pushing the third control reversing valve 81 to change direction, and conducting the oil circuit between steering pump 22 and oil port P0. The flow route of hydraulic oil pumped by working pump 21 is: working pump 21, oil port P0, boom reversing valve 31, rodless chamber of boom oil cylinder 33, and the flow route of hydraulic oil pumped by steering pump 22 is: steering pump 22, third control reversing valve 81, oil port P0, boom reversing valve 31, rodless chamber of boom oil cylinder 33. The hydraulic oil of steering pump 22 and working pump 21 merge to jointly push the cylinder rod of boom oil cylinder 33 to extend outward.

[0066] It is worth mentioning that if steering is required during lifting, the steering pump 22 will first ensure steering and then merge with the working pump 21.

[0067] It is worth mentioning that when the oil pressure at the oil port P0 reaches the unloading threshold, the hydraulic oil flows to the hydraulic control end of the overflow valve 52, pushing the overflow valve 52 to change direction and conduct, so that the hydraulic oil can reach the hydraulic control end e5 of the unloading reversing valve 51, pushing the unloading reversing valve 51 to change direction and conduct, so that the hydraulic oil can flow back to the oil tank 1 through the unloading reversing valve 51 to unload the working pump 21.

[0068] The above control is used in situations where dual pumps are required to supply oil to the working valve group, such as boom lifting, boom lifting plus bucket retracting, and boom lifting plus bucket unloading.

[0069] When the boom is lowered (not supporting the vehicle), the working pump 21 and the steering pump 22 do not need to supply oil to the working valve group, and the rod chamber is replenished by returning oil from the rodless chamber of the boom cylinder 33. The electric control handle 131 communicates with the controller 13, and the controller 13 sends a current signal to the second hydraulically controlled end reversing valve 62 and the second control reversing valve 72, so that the second hydraulically controlled end reversing valve 62 and the second control reversing valve 72 are switched. Specifically, the second hydraulically controlled end reversing valve 62 switches the oil path from the accumulator 4 to the hydraulically controlled end e2 of the boom reversing valve 31. A pilot oil flow route is: accumulator 4, pressure reducing valve 11, second hydraulically controlled end reversing valve 62, hydraulically controlled end e2 of the boom reversing valve 31, pushing the boom reversing valve 31 to reverse, and the boom reversing valve 31 moves rightward to move the valve core to the lowered position. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, second control reversing valve 72, hydraulic control end e5 of unloading reversing valve 51, pushing unloading reversing valve 51 to switch to conduction. The hydraulic oil pumped by working pump 21 flows through: working pump 21, unloading reversing valve 51, oil tank 1, realizing hydraulic oil unloading of working pump 21. Since there is no hydraulic oil at the hydraulic control end e6 of the third control reversing valve 81 at this time, the third control reversing valve 81 does not switch, and there is no conduction between steering pump 22 and oil port P0. Therefore, steering pump 22 only adjusts the displacement of steering pump 22 according to the feedback of steering system Ls signal at this time to supply oil to steering gear 9.

[0070] When the bucket is retracted, the working pump 21 is unloaded, and the steering pump 22 supplies oil to the bucket reversing valve 32 of the working valve group. The electric control handle 131 communicates with the controller 13, and the controller 13 sends a current signal to the third hydraulically controlled reversing valve 63, the first control reversing valve 71, and the second control reversing valve 72, so that the third hydraulically controlled reversing valve 63, the first control reversing valve 71, and the second control reversing valve 72 are reversed. Specifically, the third hydraulically controlled reversing valve 63 switches the oil path from the accumulator 4 to the hydraulically controlled end e3 of the bucket reversing valve 32. A pilot oil flow route is: accumulator 4, pressure reducing valve 11, third hydraulically controlled reversing valve 63, hydraulically controlled end e3 of bucket reversing valve 32, pushing the bucket reversing valve 32 to reverse, and the bucket reversing valve 32 moves left to move the valve core to the retracted position. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, first control reversing valve 71, hydraulic control end e6 of third control reversing valve 81, pushing the third control reversing valve 81 to change direction, and conducting the oil circuit between steering pump 22 and oil port P0. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, second control reversing valve 72, hydraulic control end e5 of unloading reversing valve 51, pushing unloading reversing valve 51 to change direction to conduction. The flow route of hydraulic oil pumped by working pump 21 is: working pump 21, unloading reversing valve 51, oil tank 1, realizing unloading of hydraulic oil of working pump 21. The flow route of hydraulic oil pumped by steering pump 22 is: steering pump 22, third control reversing valve 81, oil port P0, bucket reversing valve 32, rod chamber of bucket oil cylinder 34, pushing the cylinder rod of bucket oil cylinder 34 to extend outward, realizing bucket retracting action.

[0071] When the bucket tipping unloads, the working pump 21 is unloaded, and the steering pump 22 supplies oil to the bucket reversing valve 32 of the working valve group. The electric control handle 131 communicates with the controller 13, and the controller 13 sends a current signal to the fourth hydraulic control end reversing valve 64, the first control reversing valve 71 and the second control reversing valve 72, so that the fourth hydraulic control end reversing valve 64, the first control reversing valve 71 and the second control reversing valve 72 are reversed. Specifically, the fourth hydraulic control end reversing valve 64 switches the oil path from the accumulator 4 to the hydraulic control end e4 of the bucket reversing valve 32. A pilot oil flow route is: accumulator 4, pressure reducing valve 11, fourth hydraulic control end reversing valve 64, hydraulic control end e4 of bucket reversing valve 32, pushing the bucket reversing valve 32 to reverse, and the bucket reversing valve 32 moves right to move the valve core to the tipping position. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, first control reversing valve 71, hydraulic control end e6 of third control reversing valve 81, pushing the third control reversing valve 81 to change direction, and connecting the oil circuit between steering pump 22 and oil port P0. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, second control reversing valve 72, hydraulic control end e5 of unloading reversing valve 51, pushing the unloading reversing valve 51 to change direction to conduction. The flow route of the hydraulic oil pumped by the working pump 21 is: working pump 21, unloading reversing valve 51, oil tank 1, realizing the unloading of the hydraulic oil of the working pump 21. The hydraulic oil pumped by the steering pump 22 flows through the steering pump 22, the third control reversing valve 81, the oil port P0, the bucket reversing valve 32, and the rodless chamber of the bucket cylinder 34, pushing the cylinder rod of the bucket cylinder 34 to retract, thereby realizing the bucket tipping and unloading action.

[0072] When the boom is lowered and the bucket is retracted, the electric control handle 131 communicates with the controller 13, and the controller 13 sends a current signal to the second control end reversing valve, the third hydraulic end reversing valve 63, the first control reversing valve 71 and the second control reversing valve 72, so that the second control end reversing valve, the third hydraulic end reversing valve 63, the first control reversing valve 71 and the second control reversing valve 72 are reversed. Specifically, the second hydraulic end reversing valve 62 reverses the oil path from the accumulator 4 to the hydraulic end e2 of the boom reversing valve 31, and the third hydraulic end reversing valve 63 reverses the oil path from the accumulator 4 to the hydraulic end e3 of the bucket reversing valve 32. A pilot oil flow route is: accumulator 4, pressure reducing valve 11, second hydraulic end reversing valve 62, hydraulic end e2 of the boom reversing valve 31, pushing the boom reversing valve 31 to reverse, and the boom reversing valve 31 moves rightward to move the valve core to the lowered position. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, third hydraulic control end reversing valve 63, hydraulic control end e3 of bucket reversing valve 32, pushing bucket reversing valve 32 to change direction, bucket reversing valve 32 moves left to move the valve core to the bucket retracting position. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, first control reversing valve 71, hydraulic control end e6 of third control reversing valve 81, pushing third control reversing valve 81 to change direction, and connecting the oil circuit between steering pump 22 and oil port P0. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, second control reversing valve 72, hydraulic control end e5 of unloading reversing valve 51, pushing unloading reversing valve 51 to change direction to conduction. The flow route of the hydraulic oil pumped by working pump 21 is: working pump 21, unloading reversing valve 51, oil tank 1, realizing the unloading of hydraulic oil of working pump 21. One of the hydraulic oil pumped by the steering pump 22 flows through the steering pump 22, the third control reversing valve 81, the oil port P0, the boom reversing valve 31, and the rodless chamber of the boom cylinder 33, pushing the cylinder rod of the boom cylinder 33 to retract and realize the lowering action of the boom. Another route of the hydraulic oil pumped by the steering pump 22 flows through the steering pump 22, the third control reversing valve 81, the oil port P0, the bucket reversing valve 32, and the rod chamber of the bucket cylinder 34, pushing the cylinder rod of the bucket cylinder 34 to extend and realize the retracting action of the bucket.

[0073] When the boom is lowered and the bucket is dumped to unload, the electric control handle 131 communicates with the controller 13, and the controller 13 sends a current signal to the second control end reversing valve, the fourth hydraulic control end reversing valve 64, the first control reversing valve 71 and the second control reversing valve 72, so that the second control end reversing valve, the third hydraulic control end reversing valve 63, the first control reversing valve 71 and the second control reversing valve 72 are switched. Specifically, the second hydraulic control end reversing valve 62 switches the oil path from the accumulator 4 to the hydraulic control end e2 of the boom reversing valve 31, and the fourth hydraulic control end reversing valve 64 switches the oil path from the accumulator 4 to the hydraulic control end e4 of the bucket reversing valve 32. A pilot oil flow route is: accumulator 4, pressure reducing valve 11, second hydraulic control end reversing valve 62, hydraulic control end e2 of the boom reversing valve 31, pushing the boom reversing valve 31 to switch, and the boom reversing valve 31 moves rightward to move the valve core to the lowered position. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, fourth hydraulic control end reversing valve 64, hydraulic control end e4 of bucket reversing valve 32, pushing bucket reversing valve 32 to change direction, bucket reversing valve 32 moves rightward to move the valve core to the tipping bucket position. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, first control reversing valve 71, hydraulic control end e6 of third control reversing valve 81, pushing third control reversing valve 81 to change direction, and connecting the oil circuit between steering pump 22 and oil port P0. Another pilot oil flow route is: accumulator 4, pressure reducing valve 11, second control reversing valve 72, hydraulic control end e5 of unloading reversing valve 51, pushing unloading reversing valve 51 to change direction to conduction. The flow route of the hydraulic oil pumped by working pump 21 is: working pump 21, unloading reversing valve 51, oil tank 1, realizing unloading of hydraulic oil of working pump 21. One of the hydraulic oil pumped by the steering pump 22 flows through the steering pump 22, the third control reversing valve 81, the oil port P0, the boom reversing valve 31, and the rodless chamber of the boom cylinder 33, pushing the cylinder rod of the boom cylinder 33 to retract, thereby realizing the lowering action of the boom. Another of the hydraulic oil pumped by the steering pump 22 flows through the steering pump 22, the third control reversing valve 81, the oil port P0, the bucket reversing valve 32, and the five-rod chamber of the bucket cylinder 34, pushing the cylinder rod of the bucket cylinder 34 to retract, thereby realizing the bucket tipping and unloading action.

[0074] When the boom needs to float, the working pump 21 supplies oil to the boom reversing valve 31 of the working valve group, and the steering pump 22 does not supply oil. The electric control handle 131 communicates with the controller 13, and the controller 13 sends a current signal to the second hydraulically controlled reversing valve 62, so that the second hydraulically controlled reversing valve 62 and the second control reversing valve 72 are switched. Specifically, the second hydraulically controlled reversing valve 62 switches the oil path from the accumulator 4 to the hydraulically controlled end e2 of the boom reversing valve 31. A pilot oil flow route is: accumulator 4, pressure reducing valve 11, second hydraulically controlled reversing valve 62, hydraulically controlled end e2 of the boom reversing valve 31, pushing the boom reversing valve 31 to reverse, and the boom reversing valve 31 moves right to move the valve core to the floating position. Since there is no hydraulic oil at the hydraulic control end e6 of the third control reversing valve 81 at this time, the third control reversing valve 81 does not reverse, and there is no conduction between the steering pump 22 and the oil port P0. Therefore, the steering pump 22 only adjusts the displacement of the steering pump 22 according to the steering system Ls signal feedback to supply oil to the steering gear 9.

[0075] It is worth mentioning that although both boom floating and boom lowering require the controller 13 to send a current signal to the second hydraulic-controlled end reversing valve 62, since the valve core of the boom reversing valve 31 needs to be pushed to reversing to different working positions, the current signals sent by the controller 13 in these two situations are different.

[0076] When the boom is lowered and supports the vehicle, the working pump 21 supplies oil to the boom reversing valve 31 of the working valve group, and the steering pump 22 does not supply oil to the working valve group. At this time, the electric control handle 131 communicates with the controller 13, and the controller 13 sends a current signal to the second hydraulic control end reversing valve 62, so that the second hydraulic control end reversing valve 62 is reversed. Specifically, the second hydraulic control end reversing valve 62 switches the oil path from the accumulator 4 to the hydraulic control end e2 of the boom reversing valve 31. The pilot oil flows through the route: accumulator 4, pressure reducing valve 11, second hydraulic control end reversing valve 62, hydraulic control end e2 of the boom reversing valve 31, pushing the boom reversing valve 31 to reverse, and the boom reversing valve 31 moves right to move the valve core to the lowered position. The hydraulic oil pumped by the working pump 21 flows through the working pump 21, the oil port P0, the boom reversing valve 31, and the rod chamber of the boom oil cylinder 33, pushing the cylinder rod of the boom oil cylinder 33 to retract. Since there is no hydraulic oil at the hydraulic control end e6 of the third control reversing valve 81 at this time, the third control reversing valve 81 does not reverse, and there is no conduction between the steering pump 22 and the oil port P0. Therefore, the steering pump 22 only adjusts the displacement of the steering pump 22 according to the feedback of the steering system Ls signal at this time to supply oil to the steering gear 9.

[0077] When the loader is in a state of being turned off but not powered off, and the boom needs to be lowered, the electric control handle 131 communicates with the controller 13, and the controller 13 sends a current signal to the second hydraulic end reversing valve 62, so that the second hydraulic end reversing valve 62 is reversed. Specifically, the second hydraulic end reversing valve 62 reverses the oil path from the accumulator 4 to the hydraulic end e2 of the boom reversing valve 31. The pilot oil flows through the accumulator 4, the pressure reducing valve 11, the second hydraulic end reversing valve 62, and the hydraulic end e2 of the boom reversing valve 31, pushing the boom reversing valve 31 to reverse, and the boom reversing valve 31 moves rightward to move the valve core to the lowering position. The boom cylinder 33 descends due to the deadweight of the working device, the boom rodless chamber returns oil and replenishes oil to the rod chamber. After descending to the right position, the electric control handle 131 communicates with the controller 13, and the controller 13 stops sending the current signal to the second hydraulic control end reversing valve 62, and the second hydraulic control end reversing valve 62 loses power.

[0078] In summary, the loader hydraulic control system provided in this embodiment can realize the on-demand operation of the working pump 21 and the steering pump 22 through the coordinated control of the unloading valve group, the first control valve group, the second control valve group and the third control valve group, and control the switching action of the boom reversing valve 31 and the bucket reversing valve 32 through the first control valve group, thereby realizing the corresponding control of the loader boom lifting and the bucket folding. The unloading valve group is used to control whether the working pump 21 is unloaded; the second control valve group is used to control whether the pilot oil of the accumulator 4 controls the opening of the unloading valve group; the third control valve group is used to control whether the steering pump 22 is connected to the oil port P0, that is, whether the steering pump 22 is merged with the working pump 21. The working pump 21 and the steering pump 22 work on demand, thereby realizing the sequential distribution of the power of the entire hydraulic system, the system has a high degree of electronic control, and the system is more energy-saving.

[0079] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A loader hydraulic control system, characterized in that: It comprises an oil tank (1), a working pump (21), a steering pump (22), a working valve group, an accumulator (4), an unloading valve group, a first control reversing valve group, a second control valve group and a third control valve group; wherein: The oil inlets of the working pump (21) and the steering pump (22) are connected to the oil tank (1); The working valve group comprises a boom reversing valve (31) and a bucket reversing valve (32), the boom reversing valve (31) having a hydraulic control end e1 and a hydraulic control end e2, the bucket reversing valve (32) having a hydraulic control end e3 and a hydraulic control end e4, the working valve group having an oil port P0, the oil port P0 being connected to the oil inlet of the boom reversing valve (31) and the bucket reversing valve (32); The working pump (21) is connected to the oil port P0, the unloading valve group is arranged on the connecting pipeline between the oil outlet of the working pump (21) and the oil port P0, and the unloading valve group is used to unload the working pump (21); The accumulator (4) can be connected or disconnected with the hydraulic control end e1, the hydraulic control end e2, the hydraulic control end e3 and the hydraulic control end e4 respectively through the first control reversing valve group; The accumulator (4) can be connected or disconnected with the unloading valve group through the second control valve group, and the unloading valve group can be opened when the accumulator (4) is connected with the unloading valve group; The steering pump (22) can be connected to or disconnected from the oil port P0 through the third control valve group.

2. The loader hydraulic control system according to claim 1, characterized in that: The unloading valve group comprises an unloading reversing valve (51) and a relief valve (52); the oil outlet of the working pump (21) is connected to the oil inlet of the unloading reversing valve (51) and the oil inlet of the relief valve (52); the oil outlet of the unloading reversing valve (51) is connected to the oil tank (1); and the oil outlet of the relief valve (52) is connected to the hydraulic control end e5 of the unloading reversing valve (51) and the oil tank (1); The accumulator (4) can be connected to or disconnected from the oil outlet of the unloading reversing valve (51) through the second control valve group.

3. The loader hydraulic control system according to claim 2, characterized in that: The unloading valve group further comprises a first one-way valve (53), wherein the first one-way valve (53) is configured to conduct hydraulic oil in one direction from the oil inlet of the unloading reversing valve (51) to the oil inlet of the overflow valve (52).

4. The loader hydraulic control system according to claim 1, characterized in that: The first control reversing valve group comprises a first hydraulic-controlled-end reversing valve (61), a second hydraulic-controlled-end reversing valve (62), a third hydraulic-controlled-end reversing valve (63) and a fourth hydraulic-controlled-end reversing valve (64); the accumulator (4) is respectively connected to the oil inlets of the first hydraulic-controlled-end reversing valve (61), the second hydraulic-controlled-end reversing valve (62), the third hydraulic-controlled-end reversing valve (63) and the fourth hydraulic-controlled-end reversing valve (64); the oil outlet of the first hydraulic-controlled-end reversing valve (61) is connected to the hydraulic-controlled end e1, the oil outlet of the second hydraulic-controlled-end reversing valve (62) is connected to the hydraulic-controlled end e2, the oil outlet of the third hydraulic-controlled-end reversing valve (63) is connected to the hydraulic-controlled end e3, and the oil outlet of the fourth hydraulic-controlled-end reversing valve (64) is connected to the hydraulic-controlled end e4.

5. The loader hydraulic control system according to claim 4, characterized in that: The first hydraulically controlled end reversing valve (61), the second hydraulically controlled end reversing valve (62), the third hydraulically controlled end reversing valve (63) and the fourth hydraulically controlled end reversing valve (64) are all configured as electromagnetic reversing valves.

6. The loader hydraulic control system according to claim 4, characterized in that: It also includes a pressure reducing valve (11), the accumulator (4) is connected to the oil inlet of the pressure reducing valve (11), and the oil outlet of the pressure reducing valve (11) is respectively connected to the oil inlets of the first hydraulically controlled end reversing valve (61), the second hydraulically controlled end reversing valve (62), the third hydraulically controlled end reversing valve (63), and the fourth hydraulically controlled end reversing valve (64).

7. The loader hydraulic control system according to claim 1, characterized in that: The second control valve group includes a first control reversing valve (71) and a second control reversing valve (72), and the third control valve group includes a third control reversing valve (81); wherein, The accumulator (4) is connected to the oil inlet of the first control reversing valve (71) and the oil inlet of the second control reversing valve (72); the oil outlet of the first control reversing valve (71) is connected to the hydraulic control end e6 of the third control reversing valve (81); the oil outlet of the second control reversing valve (72) is connected to the unloading valve group; the oil outlet of the steering pump (22) is connected to the oil inlet of the third control reversing valve (81); and the oil outlet of the third control reversing valve (81) is connected to the oil port P0.

8. The loader hydraulic control system according to claim 7, characterized in that: It also includes a steering gear (9) and a flow amplification valve (10), the steering pump (22) is configured as a plunger pump, an oil outlet of the steering pump (22) is connected to the steering gear (9) and the flow amplification valve (10), the steering gear (9) has a first feedback oil port, and the flow amplification valve (10) has a second feedback oil port; The third control valve group further comprises a shuttle valve (82), wherein a working oil port B1 of the shuttle valve (82) is connected to an oil outlet of the third control reversing valve (81), a working oil port B2 of the shuttle valve (82) is connected to the first feedback oil port and the second feedback oil port, and a working oil port B3 of the shuttle valve (82) is connected to a third feedback oil port of the steering pump (22), and the displacement of the steering pump (22) is adjusted according to the pressure of the third feedback oil port.

9. The loader hydraulic control system according to claim 8, characterized in that: A second one-way valve (83) is provided between the working oil port B3 of the shuttle valve (82) and the third feedback oil port, and the second one-way valve (83) is configured to conduct hydraulic oil in a one-way direction from the working oil port B3 to the third feedback oil port.

10. The loader hydraulic control system according to claim 7, characterized in that: The first control reversing valve (71) and the second control reversing valve (72) are both configured as electromagnetic reversing valves.

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