Dual pump oil supply system, gearbox assembly and engineering machinery

Abstract

The present invention relates to the technical field related to engineering machinery, and specifically to a dual-pump oil supply system, a gearbox assembly and engineering machinery. The dual-pump oil supply system includes a first oil pump, a second oil pump, a first oil circuit, a second oil circuit, a third oil circuit and a reversing valve, and the reversing valve includes: a valve body, having a valve core cavity, a first oil inlet, a second oil inlet, a first oil outlet, a second oil outlet, an oil inlet and an oil outlet, the first oil pump is connected to the first oil inlet through the first oil circuit, the second oil pump is connected to the second oil inlet through the second oil circuit, one end of the third oil circuit is connected to the oil inlet and the outlet and the other end is connected to the second oil circuit; a valve core is movably arranged in the valve core cavity, and the valve core of the reversing valve is controlled to move by the pressure difference between the first oil pump and the second oil pump, so that the first oil circuit and the second oil circuit are connected or disconnected through the third oil circuit. The present invention can realize reversing and pressure regulation through a reversing valve, the number of valves is small, the cost is low, and the problem of complex structure caused by three valves is solved.

Description

Technical Field

[0001] The present invention relates to the technical field related to engineering machinery, and in particular to a dual-pump oil supply system, a gearbox assembly and engineering machinery. Background Art

[0002] In the prior art, the gearbox generally supplies oil to the hydraulic system through a mechanical oil pump, which is driven by the engine. The oil supply of the oil pump is directly related to the engine speed. Under low engine speed conditions, in order to meet the oil supply demand of the gearbox, the displacement of the mechanical oil pump needs to be designed to be large. However, when the engine speed is high, the flow rate of the oil pump is much greater than the required flow rate, and the oil pump consumes a lot of engine power, reducing the transmission efficiency of the gearbox and increasing the fuel consumption of the whole vehicle.

[0003] In order to improve the fuel economy of the whole vehicle and reduce the loss of the automatic transmission hydraulic system, more and more automatic transmission hydraulic systems adopt a dual oil pump oil supply system. The dual oil pump oil supply system includes a main pump, an auxiliary pump, a solenoid valve, a reversing valve, and a switch valve. The auxiliary pump is connected to the reversing valve and the switch valve, and the main pump is connected to the inlet of the solenoid valve. The reversing of the reversing valve can be controlled by the solenoid valve. The above dual pump oil supply system is used in conjunction with three valves, has a complex structure, and is costly, and the main oil circuit cannot supply oil to the auxiliary oil circuit. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the dual-pump oil supply system in the prior art that is complex in structure and high in cost due to the coordinated use of three valves, thereby providing a dual-pump oil supply system, a gearbox assembly and engineering machinery. The dual-pump oil supply system can achieve reversing and pressure regulation through a reversing valve, with a small number of valves and low cost.

[0005] In order to solve the above problems, the present invention provides a dual-pump oil supply system, including a first oil pump, a second oil pump, a first oil circuit, a second oil circuit, a third oil circuit and a reversing valve, the reversing valve including: a valve body, having a valve core cavity and a first oil inlet, a second oil inlet, a first oil outlet, a second oil outlet, and an oil inlet and an outlet connected to the valve core cavity, an oil discharge port of the first oil pump being connected to the first oil inlet through the first oil circuit, an oil discharge port of the second oil pump being connected to the second oil inlet through the second oil circuit, one end of the third oil circuit being connected to the oil inlet and an outlet and the other end being connected to the second oil circuit; a valve core being movably arranged in the valve core cavity, the valve core movement of the reversing valve being controlled by the pressure difference between the first oil pump and the second oil pump so that the first oil circuit and the second oil circuit are connected or disconnected through the third oil circuit.

[0006] Optionally, a connecting passage connecting the first oil circuit and the third oil circuit is provided on the valve core; wherein the valve core has a first working position, a second working position and an intermediate working position between the first working position and the second working position, and when the valve core is in the first working position, the first oil circuit and the second oil circuit are connected to the third oil circuit through the connecting passage; when the valve core is in the second working position, the first oil circuit and the second oil circuit are connected through the third oil circuit; when the valve core is in the intermediate working position, the first oil circuit and the second oil circuit are not connected.

[0007] Optionally, the reversing valve also includes a first elastic element and a second elastic element arranged on both sides of the valve core. Under the action of the first elastic element, the second elastic element, the pressure of the hydraulic oil in the first oil circuit and the pressure of the hydraulic oil in the second oil circuit, the valve core switches between the first working position, the second working position and the intermediate working position.

[0008] Optionally, the first elastic element and the second elastic element are both springs.

[0009] Optionally, the oil inlet and outlet are located between the first oil inlet and the second oil inlet, and the connecting passage includes a horizontal section and a vertical section.

[0010] Optionally, the dual-pump oil supply system also includes an oil tank, a fourth oil circuit, a fifth oil circuit and a first pressure regulating valve, one end of the fourth oil circuit is connected to the second oil outlet, one end of the fifth oil circuit is connected to the fourth oil circuit and the other end is connected to the oil tank, and the first pressure regulating valve is arranged on the fifth oil circuit.

[0011] Optionally, the first pressure regulating valve is a relief valve.

[0012] Optionally, the dual-pump oil supply system also includes a sixth oil circuit, a seventh oil circuit and a second pressure regulating valve, one end of the sixth oil circuit is connected to the first oil outlet, one end of the seventh oil circuit is connected to the sixth oil circuit and the other end is connected to the oil tank, and the second pressure regulating valve is arranged on the seventh oil circuit.

[0013] The present invention also provides a gearbox assembly, comprising a gearbox and the above-mentioned dual-pump oil supply system.

[0014] The present invention also provides an engineering machine, comprising: the above-mentioned gearbox assembly.

[0015] The present invention has the following advantages: the valve core of the reversing valve is controlled to move by the pressure difference of the two oil pumps, so that the first oil circuit and the second oil circuit are connected or disconnected through the third oil circuit. When the first oil circuit and the second oil circuit are connected through the third oil circuit, the pressure of the first oil circuit and the second oil circuit can be adjusted, and the first oil pump can supply oil to the first oil circuit and the second oil circuit, or the second oil pump can supply oil to the first oil circuit and the second oil circuit; when the first oil circuit and the second oil circuit are disconnected, the first oil pump supplies oil to the first oil circuit and the second oil pump supplies oil to the second oil circuit. The above-mentioned dual-pump oil supply system can realize reversal and pressure regulation through a reversing valve, the number of valves is small, the cost is low, and the problem of complex structure and high cost caused by the use of three valves in conjunction with the dual-pump oil supply system is effectively solved. The reversing valve is controlled by the pressure difference of the two oil pumps, and the solenoid valve is cancelled, the control is simpler, and it can ensure that when one oil pump is damaged, the other oil pump supplies oil to the two oil circuits at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A simplified schematic diagram showing the valve core of the dual-pump oil supply system of the present invention is in the middle working position;

[0018] Figure 2 Shows Figure 1 A simplified schematic diagram of a dual-pump oil supply system in which the valve core is in the first working position;

[0019] Figure 3 Shows Figure 1 A simplified schematic diagram of a dual pump oil supply system with the valve core in the second working position.

[0020] Description of reference numerals:

[0021] 11. First oil pump; 12. Second oil pump; 21. First oil circuit; 22. Second oil circuit; 23. Third oil circuit; 24. Fourth oil circuit; 25. Fifth oil circuit; 26. Sixth oil circuit; 27. Seventh oil circuit; 30. Reversing valve; 31. Valve body; 311. Valve core chamber; 312. First oil inlet; 313. Second oil inlet; 314. First oil outlet; 315. Second oil outlet; 316. Oil inlet and outlet; 32. Valve core; 321. Connecting channel; 33. First elastic element; 34. Second elastic element; 40. Oil tank; 51. First pressure regulating valve; 52. Second pressure regulating valve. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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 it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] like Figure 1 As shown, the dual-pump oil supply system of this embodiment includes a first oil pump 11, a second oil pump 12, a first oil circuit 21, a second oil circuit 22, a third oil circuit 23 and a reversing valve 30. The reversing valve 30 includes a valve body 31 and a valve core 32. The valve body 31 has a valve core cavity 311 and a first oil inlet 312, a second oil inlet 313, a first oil outlet 314, a second oil outlet 315, and an oil inlet and outlet 316 that are connected to the valve core cavity 311. The oil discharge port of the first oil pump 11 is connected to the first oil circuit 21 through the first oil circuit 22. The valve core 32 is movably arranged in the valve core chamber 311, and the valve core 32 of the reversing valve 30 is controlled to move by the pressure difference between the first oil pump 11 and the second oil pump 12, so that the first oil circuit 21 and the second oil circuit 22 are connected or disconnected through the third oil circuit 23.

[0027] The dual-pump oil supply system of this embodiment is applied, and the valve core 32 of the reversing valve 30 is controlled to move by the pressure difference between the first oil pump 11 and the second oil pump 12, so that the first oil circuit 21 and the second oil circuit 22 are connected or disconnected through the third oil circuit 23. When the first oil circuit 21 and the second oil circuit 22 are connected through the third oil circuit 23, the pressure of the first oil circuit 21 and the second oil circuit 22 can be adjusted, and the first oil pump 11 can supply oil to the first oil circuit 21 and the second oil circuit 22, or the second oil pump 12 can supply oil to the first oil circuit 21 and the second oil circuit 22; when the first oil circuit 21 and the second oil circuit 22 are disconnected, the first oil pump 11 supplies oil to the first oil circuit 21, and the second oil pump 12 supplies oil to the second oil circuit 22. The above-mentioned dual-pump oil supply system can achieve reversing and pressure regulation through a reversing valve 30. The number of valves is small and the cost is low. It effectively solves the problem of complex structure and high cost caused by the use of three valves in conjunction with the dual-pump oil supply system. The reversing valve is controlled by the pressure difference between the two oil pumps, and the solenoid valve is eliminated, which makes the control simpler. It can also ensure that when one oil pump is damaged, the other oil pump supplies oil to both oil circuits at the same time.

[0028] In this embodiment, if Figures 1 to 3 As shown, the valve core 32 is provided with a connecting passage 321 which can connect the first oil circuit 21 and the third oil circuit 23; wherein the valve core 32 has a first working position, a second working position and an intermediate working position between the first working position and the second working position. When the valve core 32 is in the first working position, the first oil circuit 21 and the second oil circuit 22 are connected to the third oil circuit 23 through the connecting passage 321; when the valve core 32 is in the second working position, the first oil circuit 21 and the second oil circuit 22 are connected through the third oil circuit 23; when the valve core 32 is in the intermediate working position, the first oil circuit 21 and the second oil circuit 22 are not connected. The valve core 32 divides the valve core cavity 311 into a first cavity and a second cavity. The first oil inlet and the first oil outlet are connected through the first cavity, and the second oil inlet and the second oil outlet are connected through the second cavity. During the movement of the valve core 32, the total volume of the first cavity and the second cavity remains unchanged, and the volumes of the first cavity and the second cavity increase and decrease. Specifically, as Figure 2 As shown, during the movement of the valve core 32 to the left, the volume of the first cavity gradually decreases, and the volume of the second cavity gradually increases. When the connecting passage 321 is connected with the third oil passage 23, the hydraulic oil in the second oil passage 22 enters the first cavity through the third oil passage 23 and the connecting passage 321, and the second oil pump 12 supplies oil to the first oil passage 21 and the second oil passage 22; Figure 3 As shown, during the movement of the valve core 32 to the right, the volume of the first cavity gradually increases, and the volume of the second cavity gradually decreases. When the valve core 32 moves to expose the oil inlet and outlet 316, the hydraulic oil in the first oil circuit 21 flows into the second oil circuit 22 through the third oil circuit 23, and the first oil pump 11 supplies oil to the first oil circuit 21 and the second oil circuit 22.

[0029] In this embodiment, the reversing valve 30 further includes a first elastic element 33 and a second elastic element 34 disposed on both sides of the valve core 32. Under the action of the first elastic element 33, the second elastic element 34, the pressure of the hydraulic oil in the first oil circuit 21, and the pressure of the hydraulic oil in the second oil circuit 22, the valve core 32 switches between the first working position, the second working position, and the intermediate working position. There is no need to set a driving mechanism for driving the movement of the valve core 32. The valve core 32 can be driven to move according to the pressure of the hydraulic oil in the first oil circuit 21 and the second oil circuit 22, thereby realizing the reversal and pressure regulation of the reversing valve, and the structure is simple. It can be understood that in other embodiments, a pressure sensor for detecting the first oil circuit 21 and the second oil circuit 22, a driving mechanism for driving the movement of the valve core 32, and a controller can also be provided, and the controller controls the driving mechanism according to the pressure detected by the pressure sensor.

[0030] In this embodiment, the first elastic element 33 and the second elastic element 34 are both springs, which are easy to use and low in cost.

[0031] In this embodiment, the oil inlet and outlet 316 is located between the first oil inlet 312 and the second oil inlet 313 , and the communication channel 321 includes a horizontal section and a vertical section, which has a simple structure and is easy to manufacture.

[0032] In this embodiment, the dual-pump oil supply system further includes an oil tank 40, a fourth oil circuit 24, a fifth oil circuit 25 and a first pressure regulating valve 51. One end of the fourth oil circuit 24 is connected to the second oil outlet 315, one end of the fifth oil circuit 25 is connected to the fourth oil circuit 24 and the other end is connected to the oil tank 40, and the first pressure regulating valve 51 is arranged on the fifth oil circuit 25. When the pressure in the second oil circuit 22 is relatively high, the hydraulic oil in the second oil circuit 22 is unloaded into the oil tank 40 through the first pressure regulating valve 51, so that the pressure in the second oil circuit 22 is maintained within a certain range. Preferably, the first pressure regulating valve 51 is a relief valve. When the pressure in the second oil circuit 22 exceeds the preset pressure of the relief valve, the hydraulic oil in the second oil circuit 22 is unloaded into the oil tank 40 through the relief valve. It can be understood that in other embodiments, the fifth oil circuit 25 and the first pressure regulating valve 51 may not be arranged.

[0033] In this embodiment, the dual-pump oil supply system further includes a sixth oil circuit 26, a seventh oil circuit 27 and a second pressure regulating valve 52. One end of the sixth oil circuit 26 is connected to the first oil outlet 314, one end of the seventh oil circuit 27 is connected to the sixth oil circuit 26 and the other end is connected to the oil tank 40, and the second pressure regulating valve 52 is arranged on the seventh oil circuit 27. When the pressure in the first oil circuit 21 is relatively high, the hydraulic oil in the first oil circuit 21 is unloaded into the oil tank 40 through the second pressure regulating valve 52, so that the pressure in the first oil circuit 21 is maintained within a certain range. Preferably, the second pressure regulating valve 52 is a relief valve. When the pressure in the first oil circuit 21 exceeds the preset pressure of the relief valve, the hydraulic oil in the first oil circuit 21 is unloaded into the oil tank 40 through the relief valve. It can be understood that in other embodiments, the seventh oil circuit 27 and the second pressure regulating valve 52 may not be arranged.

[0034] It should be noted that the first oil pump 11 is an auxiliary pump, the second oil pump 12 is a main pump, the first oil circuit 21 is an auxiliary oil circuit, and the second oil circuit 22 is a main oil circuit. It is understandable that in other embodiments, the first oil pump 11 is a main pump, the second oil pump 12 is an auxiliary pump, the first oil circuit 21 is a main oil circuit, and the second oil circuit 22 is an auxiliary oil circuit.

[0035] Combine the following Figures 1 to 3 Explain the working process of the dual pump oil supply system:

[0036] When the pressures of the first oil circuit 21 and the second oil circuit 22 are both within the set range, under the combined action of the oil pressure, the first elastic element 33 and the second elastic element 34, the valve core 32 is in the middle working position, the third oil circuit 23 and the connecting channel 321 are disconnected, and the first oil circuit 21 and the second oil circuit 22 are disconnected (such as Figure 1 As shown), the first oil pump 11 and the second oil pump 12 work independently, the first oil pump 11 only supplies oil to the first oil circuit 21, and the second oil pump 12 only supplies oil to the second oil circuit 22.

[0037] When the pressure of the first oil circuit 21 is greater than the set pressure, under the combined action of the two elastic elements and the oil pressure, the valve core 32 moves to the right, the first oil circuit 21, the second oil circuit 22, and the third oil circuit 23 are connected, and the oil in the first oil circuit 21 is leaked to the second oil circuit 22, so that the pressure of the first oil circuit 21 is maintained within a certain range, and the first oil pump 11 supplies oil to the first oil circuit 21 and the second oil circuit 22 at the same time (such as Figure 3 As shown), if the pressure in the first oil circuit 21 is still too high, the pressure can be released through the second pressure regulating valve 52.

[0038] When the pressure of the first oil circuit 21 is lower than the set pressure, under the joint action of the two elastic elements and the oil pressure, the valve core 32 moves to the left, the first oil circuit 21, the second oil circuit 22, the third oil circuit 23, and the connecting channel 321 are connected, and the oil in the second oil circuit 22 is supplemented to the first oil circuit 21, so that the pressure of the first oil circuit 21 is maintained within a certain range, and the second oil pump 12 supplies oil to the first oil circuit 21 and the second oil circuit 22 at the same time (such as Figure 2 shown).

[0039] When the pressure of the second oil circuit 22 is higher than the set value, under the joint action of the two elastic elements and the oil pressure, the valve core 32 moves to the left, the first oil circuit 21, the second oil circuit 22, the third oil circuit 23, and the connecting channel 321 are connected, and the oil in the second oil circuit 22 is leaked to the first oil circuit 21, so that the pressure of the first oil circuit 21 is maintained within a certain range, and the second oil pump 12 supplies oil to the first oil circuit 21 and the second oil circuit 22 at the same time (such as Figure 2 As shown), if the pressure in the second oil circuit 22 is still too high, the pressure can be released through the first pressure regulating valve.

[0040] When the pressure in the second oil circuit 22 is less than the set value, the valve core 32 moves to the right under the action of the pressure, the first oil circuit 21, the second oil circuit 22, and the third oil circuit 23 are connected, and the oil in the first oil circuit 21 is leaked to the second oil circuit 22, so that the pressure in the first oil circuit 21 is maintained within a certain range, and the first oil pump 11 supplies oil to the first oil circuit 21 and the second oil circuit 22 at the same time (such as Figure 3 shown).

[0041] The present invention also provides a gearbox assembly, comprising a gearbox and the above-mentioned dual-pump oil supply system.

[0042] The present invention also provides an engineering machine, which includes: the above-mentioned gearbox assembly. The position of the valve core 32 is automatically adjusted by the first elastic element 33, the second elastic element 34, the pressure of the hydraulic oil in the first oil circuit 21 and the pressure of the hydraulic oil in the second oil circuit 22, so that the pressure in the first oil circuit 21 and the second oil circuit 22 is maintained within a certain range, and a reversing valve is used to control the operation of two oil pumps, which simplifies the hydraulic system, reduces the loss of the hydraulic system, and improves the fuel economy of the whole vehicle. If one oil pump fails, the other oil pump can still ensure that the hydraulic system is in a controllable state.

[0043] In this embodiment, the engineering machinery is an excavator, a rotary drilling rig, a loader, etc.

[0044] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0045] 1. The dual oil pump control system includes a first oil pump 11, a second oil pump 12, a first oil circuit 21, a second oil circuit 22, a third oil circuit 23, a fourth oil circuit 24, a fifth oil circuit 25, a first elastic element 33, a second elastic element 34, a reversing valve 30 and a first pressure regulating valve 51, etc. The oil discharge port of the first oil pump 11 is connected to the first oil circuit 21, the oil discharge port of the second oil pump 12 is connected to the second oil circuit 22, the third oil circuit 23 is connected to the second oil circuit 22, and a connecting channel 321 is provided on the valve core 32. The connecting channel 321 is provided on the valve core 32. 321 can be connected to the third oil circuit 23 or not, so that the first oil circuit 21 and the second oil circuit 22 are connected or not, and the first oil pump 11 and the second oil pump 12 can supply oil to the first oil circuit 21 and the second oil circuit 22 at the same time according to the pressure. The valve core 32 of the reversing valve 30 is controlled by the pressure difference between the two oil pumps, and the solenoid valve is cancelled, which makes the control simpler. The functions of reversing and pressure regulation can be realized simultaneously through one reversing valve, which can ensure that when one oil pump is damaged, the other oil pump can supply oil to the two oil circuits at the same time.

[0046] 2. The first elastic element is located on the side of the valve core 32 close to the first oil circuit 21, and the second elastic element is located on the side of the valve core 32 close to the second oil circuit 22. When the pressure of the first oil circuit 21 and the second oil circuit 22 are within the set range, under the joint action of the two elastic elements and the oil pressure, the valve core 32 is in the middle position, so that the third oil circuit 23 is separated from the connecting channel 321, so that the first oil circuit 21 and the second oil circuit 22 can be isolated; when the pressure of the first oil circuit 21 is greater than the set pressure and / or the pressure of the second oil circuit 22 is less than the set value, the two elastic elements are in the middle position. Under the joint action of the two elastic elements and the oil pressure, the valve core 32 moves to the right, and the third oil circuit 23 connects the first oil circuit 21 and the second oil circuit 22, so that the pressure of the first oil circuit 21 is maintained within a certain range; when the pressure of the first oil circuit 21 is lower than the set pressure and / or the pressure of the second oil circuit 22 is higher than the set value, under the joint action of the two elastic elements and the oil pressure, the valve core 32 moves to the left, and the third oil circuit 23 and the connecting channel 321 connect the first oil circuit 21 and the second oil circuit 22, so that the pressure in the first oil circuit 21 is maintained within a certain range.

[0047] 3. The fourth oil circuit 24 is connected to the fifth oil circuit 25. The pressure of the fifth oil circuit is regulated by the first pressure regulating valve 51. If the pressure of the second oil circuit 22 is still too high, the first pressure regulating valve 51 regulates the pressure of the fifth oil circuit 25 and starts to drain oil. The pressures of the first oil circuit 21 and the second oil circuit 22 can be regulated by the pressure regulating valve.

[0048] 4. The pressure of the first oil circuit 21 and the second oil circuit 22 can be adjusted by a reversing valve 30, which simplifies the hydraulic system, eliminates the controller and two solenoid valves, and reduces the cost of the hydraulic system.

[0049] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A dual pump oil supply system, characterized in that: The invention comprises a first oil pump (11), a second oil pump (12), a first oil circuit (21), a second oil circuit (22), a third oil circuit (23) and a reversing valve (30), wherein the reversing valve (30) comprises: The valve body (31) comprises a valve core cavity (311) and a first oil inlet (312), a second oil inlet (313), a first oil outlet (314), a second oil outlet (315), and an oil inlet and outlet (316) which are communicated with the valve core cavity (311); the oil outlet of the first oil pump (11) is connected to the first oil inlet (312) via the first oil circuit (21); the oil outlet of the second oil pump (12) is connected to the second oil inlet (313) via the second oil circuit (22); one end of the third oil circuit (23) is connected to the oil inlet and outlet (316) and the other end is connected to the second oil circuit (22); a valve core (32) movably disposed in the valve core chamber (311), and controlling the movement of the valve core (32) of the reversing valve (30) by the pressure difference between the first oil pump (11) and the second oil pump (12), so that the first oil passage (21) and the second oil passage (22) are connected or disconnected via the third oil passage (23); The valve core (32) is provided with a communication channel (321) capable of connecting the first oil circuit (21) and the third oil circuit (23); The valve core (32) has a first working position, a second working position and an intermediate working position between the first working position and the second working position; when the valve core (32) is in the first working position, the first oil circuit (21) and the second oil circuit (22) are connected to the third oil circuit (23) via the connecting passage (321); when the valve core (32) is in the second working position, the first oil circuit (21) and the second oil circuit (22) are connected to the third oil circuit (23); when the valve core (32) is in the intermediate working position, the first oil circuit (21) and the second oil circuit (22) are not connected; The valve core (32) divides the valve core cavity (311) into a first cavity and a second cavity; the first oil inlet (312) and the first oil outlet (314) are connected through the first cavity; and the second oil inlet (313) and the second oil outlet (315) are connected through the second cavity.

2. The dual pump oil supply system according to claim 1, characterized in that: The reversing valve (30) further comprises a first elastic element (33) and a second elastic element (34) arranged on both sides of the valve core (32); under the action of the first elastic element (33), the second elastic element (34), the pressure of the hydraulic oil in the first oil circuit (21), and the pressure of the hydraulic oil in the second oil circuit (22), the valve core (32) switches between the first working position, the second working position, and the intermediate working position.

3. The dual pump oil supply system according to claim 2, characterized in that: The first elastic element (33) and the second elastic element (34) are both springs.

4. The dual pump oil supply system according to any one of claims 1 to 3, characterized in that: The oil inlet and outlet (316) is located between the first oil inlet (312) and the second oil inlet (313), and the communication channel (321) comprises a horizontal section and a vertical section.

5. The dual pump oil supply system according to any one of claims 1 to 3, characterized in that: The dual-pump oil supply system further comprises an oil tank (40), a fourth oil circuit (24), a fifth oil circuit (25) and a first pressure regulating valve (51); one end of the fourth oil circuit (24) is connected to the second oil outlet (315); one end of the fifth oil circuit (25) is connected to the fourth oil circuit (24) and the other end is connected to the oil tank (40); and the first pressure regulating valve (51) is arranged on the fifth oil circuit (25).

6. The dual pump oil supply system according to claim 5, characterized in that: The first pressure regulating valve (51) is a relief valve.

7. The dual pump oil supply system according to claim 5, characterized in that: The dual-pump oil supply system further comprises a sixth oil circuit (26), a seventh oil circuit (27) and a second pressure regulating valve (52); one end of the sixth oil circuit (26) is connected to the first oil outlet (314); one end of the seventh oil circuit (27) is connected to the sixth oil circuit (26) and the other end is connected to the oil tank (40); and the second pressure regulating valve (52) is arranged on the seventh oil circuit (27).

8. A gearbox assembly, characterized in that: The invention comprises a gearbox and a dual-pump oil supply system according to any one of claims 1 to 7.

9. An engineering machine, characterized in that: include: The gearbox assembly as claimed in claim 8.

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