Bucket rod decoupling hydraulic system and excavator

Abstract

The invention relates to the technical field of excavators, and particularly discloses a bucket rod decoupling hydraulic system and an excavator, the bucket rod decoupling hydraulic system comprises an oil supplementing pump, a first closed oil pump, a second closed oil pump, a flow balance valve, a first oil pump and a second oil pump, and the two ends of the oil supplementing pump are connected with an oil tank and an oil supplementing path respectively; the first closed oil pump and the first oil way are connected with the bucket rod oil cylinder and the second oil way to form a hydraulic loop, the two ends of the second closed oil pump are connected with the oil supplementing oil way and the third oil way respectively, the third oil way is connected with the first oil way, and the first closed oil pump and the second closed oil pump can both rotate forwards and rotate backwards. The first oil pump and the second oil pump are used for supplying oil to the movable arm oil cylinder and the bucket oil cylinder. The flow balance valve connects the one, with the smaller oil pressure, of the first oil way and the second oil way with the oil supplementing oil way. Hot oil in the hydraulic loop and normal-temperature oil in oil supplementing and returning can be replaced, it is guaranteed that the oil temperature in the hydraulic loop is normal, then normal work of the bucket rod oil cylinder is guaranteed, and temperature monitoring is not needed.

Description

Technical Field

[0001] The present invention relates to the technical field of excavators, and in particular to a boom decoupling hydraulic system and an excavator. Background Art

[0002] The hydraulic system of the excavator is used to control the movement of the boom, arm, and bucket. In order to improve the operability of the control, the hydraulic circuits of the boom, arm, and bucket are usually decoupled. In the prior art, some decoupled hydraulic circuits use open pumps to supply oil, which will cause a large impact on the system movement and there is a problem of energy waste. Some decoupled hydraulic circuits use closed pumps to drive the oil circulation and cooperate with accumulators to recover energy. Compared with open pumps, they can solve the problems of large impact on the system movement and energy waste. However, the accumulator will overflow at high pressure when it reaches the maximum pressure, and the pipelines connected to the rod chamber and the rodless chamber will also overflow at high pressure when they reach the maximum pressure. This will generate a lot of heat and affect the thermal balance of the system. In order to avoid the oil temperature in the system from being too high, additional temperature monitoring is required. When the temperature is abnormal, the hot oil in the system needs to overflow to the oil tank through the low-pressure overflow valve, and the oil in the oil tank is replenished to the system, affecting the normal operation of the oil cylinder. Summary of the invention

[0003] The purpose of the present invention is to provide a boom decoupling hydraulic system and an excavator to solve the problem that a hydraulic circuit that supplies oil with a closed pump and recovers energy with an accumulator is prone to generate a large amount of heat. When the temperature is abnormal, the hot oil in the system needs to overflow to the oil tank through a low-pressure overflow valve, and the oil in the oil tank needs to be replenished into the system, which affects the normal operation of the oil cylinder.

[0004] On the one hand, the present invention provides a boom decoupling hydraulic system, which includes a boom cylinder, a boom cylinder and a bucket cylinder, wherein the boom cylinder includes a boom rod chamber and a boom rodless chamber with variable volumes, the boom cylinder includes a boom rod chamber and a boom rodless chamber with variable volumes, the bucket cylinder includes a bucket rod chamber and a bucket rodless chamber with variable volumes, and the boom decoupling hydraulic system further includes:

[0005] An oil replenishment pump, one end of which is connected to the oil tank, and the other end of which is connected to the oil replenishment circuit;

[0006] A first closed oil pump, one end of which is connected to the first oil circuit, and the other end of which is connected to the second oil circuit, wherein the first oil circuit is connected to the rodless chamber of the boom, and the second oil circuit is connected to the rod chamber of the boom, and the first closed oil pump can rotate forward and reverse;

[0007] A second closed oil pump, one end of which is connected to the oil replenishment oil circuit, and the other end of which is connected to a third oil circuit, wherein the third oil circuit is connected to the first oil circuit, and the second closed oil pump can rotate forward and reverse;

[0008] a flow balancing valve, the flow balancing valve connecting the one with the lower oil pressure of the first oil circuit and the second oil circuit to the oil replenishment oil circuit;

[0009] a first oil pump configured to supply oil to one of the boom rod chamber and the boom rodless chamber, and one of the bucket rod chamber and the bucket rodless chamber;

[0010] The second oil pump is configured to selectively supply oil to one of the bucket rodless chamber, the boom rod chamber and the boom rodless chamber.

[0011] As a preferred technical solution of the boom decoupling hydraulic system, the boom decoupling hydraulic system also includes a regeneration valve, which is configured to connect the first oil circuit and the second oil circuit, or disconnect the first oil circuit and the second oil circuit.

[0012] As a preferred technical solution for the boom decoupling hydraulic system, the boom decoupling hydraulic system further includes a first holding valve and a first pilot valve, the first holding valve having a first pump side interface and a first cylinder side interface, the first holding valve being connected in series to the first oil circuit via the first pump side interface and the first cylinder side interface, and the first cylinder side interface being closer to the boom rodless chamber relative to the first pump side interface, the first holding valve having a first open state and a first closed state, when the first holding valve is in the first open state, the first pump side interface and the first cylinder side interface are connected, and when the first holding valve is in the first closed state, the first pump side interface and the first cylinder side interface are disconnected;

[0013] When the first holding valve is in the first closed state: the oil pressure at the first pump side interface exceeds the first set value of the oil pressure at the first cylinder side interface, so that the first holding valve switches to the first open state under the drive of the oil pressure difference, or the first pilot valve controls the first holding valve to switch to the first open state.

[0014] As a preferred technical solution of the boom decoupling hydraulic system, the boom decoupling hydraulic system further includes a second holding valve and a second pilot valve, the second holding valve having a second pump side interface and a second cylinder side interface, the second holding valve being connected in series to the second oil circuit via the second pump side interface and the second cylinder side interface, and the second cylinder side interface having a rod cavity relative to the second pump side interface close to the boom, the second holding valve having a second open state and a second closed state, when the second holding valve is in the second open state, the second pump side interface and the second cylinder side interface are connected, and when the second holding valve is in the second closed state, the second pump side interface and the second cylinder side interface are disconnected;

[0015] When the second holding valve is in the second closed state: when the oil pressure at the second pump side interface exceeds the second set value of the oil pressure at the second cylinder side interface, the second holding valve is switched to the second open state under the drive of the oil pressure difference, or the second pilot valve controls the second holding valve to switch to the second open state.

[0016] As a preferred technical solution of the boom decoupling hydraulic system, the boom decoupling hydraulic system further includes a first control valve, which is arranged in the first oil circuit and located between the first holding valve and the first closed oil pump, and is used to open or close the first oil circuit;

[0017] The first control valve is configured to open the first oil circuit when the first pilot valve controls the first holding valve to switch to the first open state and the second holding valve is switched to the second open state driven by the oil pressure difference, or when the first pilot valve switches to the first open state driven by the oil pressure difference and the second pilot valve controls the second holding valve to switch to the second open state.

[0018] As an optimal technical solution for the boom decoupling hydraulic system, the boom decoupling hydraulic system also includes a first oil replenishment check valve and a second oil replenishment check valve, the first oil replenishment check valve is connected between the oil replenishment oil circuit and the first oil circuit, and the connection between the first oil replenishment check valve and the first oil circuit is located between the first holding valve and the boom cylinder, the first oil replenishment check valve only allows oil to flow from the oil replenishment oil circuit to the first oil circuit; the second oil replenishment check valve is connected between the oil replenishment oil circuit and the second oil circuit, and the second oil replenishment check valve only allows oil to flow from the oil replenishment oil circuit to the second oil circuit.

[0019] As an optimal technical solution for the boom decoupling hydraulic system, the boom decoupling hydraulic system also includes a first overflow valve and a second overflow valve, the first overflow valve is connected between the oil replenishment circuit and the first oil circuit, and the connection between the first overflow valve and the first oil circuit is located between the first holding valve and the boom cylinder, the first overflow valve only allows oil to overflow from the first oil circuit to the oil replenishment circuit; the second overflow valve is connected between the oil replenishment circuit and the second oil circuit, and the second overflow valve only allows oil to overflow from the second oil circuit to the oil replenishment circuit.

[0020] As a preferred technical solution for the boom decoupling hydraulic system, the boom decoupling hydraulic system also includes a first motor and a battery. The first motor is capable of forward and reverse rotation. The battery is electrically connected to the first motor. The first motor is simultaneously transmission-connected to the first closed oil pump and the second closed oil pump, and the first motor is used to drive the first closed oil pump and the second closed oil pump to rotate simultaneously.

[0021] As a preferred technical solution of the boom decoupling hydraulic system, the boom decoupling hydraulic system further includes a battery, a second motor, a third motor and an oil replenishment motor, the second motor is transmission-connected to the first oil pump, the second motor is used to drive the first oil pump to rotate, the third motor is transmission-connected to the second oil pump, and the third motor is used to drive the second oil pump to rotate, the oil replenishment motor is transmission-connected to the oil replenishment pump, and the oil replenishment motor is used to drive the oil replenishment pump to rotate, and the battery is electrically connected to the second motor, the third motor and the oil replenishment motor respectively; or,

[0022] The boom decoupling hydraulic system also includes a first internal combustion engine, which is simultaneously connected to the first oil pump, the second oil pump and the replenishing oil pump, and is used to simultaneously drive the first oil pump, the second oil pump and the replenishing oil pump to rotate.

[0023] The arm decoupling hydraulic system provided by the present invention has at least the following beneficial effects:

[0024] The arm decoupling hydraulic system includes an oil replenishment pump, a first closed oil pump, a second closed oil pump, a flow balancing valve, a first oil pump and a second oil pump. One end of the oil replenishment pump is connected to the oil tank, and the other end is connected to the oil replenishment oil circuit. One end of the first closed oil pump is connected to the first oil circuit, and the other end is connected to the second oil circuit. The first oil circuit is connected to the arm without a rod cavity, and the second oil circuit is connected to the arm with a rod cavity. The first closed oil pump can rotate forward and reverse. One end of the second closed oil pump is connected to the oil replenishment oil circuit, and the other end is connected to the second oil circuit. The end is connected to the third oil circuit, the third oil circuit is connected to the first oil circuit, and the second closed oil pump can rotate forward and reverse; the flow balance valve connects the one with the smaller oil pressure in the first oil circuit and the second oil circuit to the oil replenishment circuit; the first oil pump is configured to supply oil to one of the boom rod chamber and the boom rodless chamber, and one of the bucket rod chamber and the bucket rodless chamber; the second oil pump is configured to selectively supply oil to one of the bucket rodless chamber, the boom rod chamber and the boom rodless chamber. When the temperature of the oil in the hydraulic circuit between the first closed oil pump and the boom cylinder is too high, the flow balance valve can be used to replace the hot oil in the hydraulic circuit with the oil in the oil replenishment circuit. Since the temperature of the oil in the oil replenishment circuit is relatively low, the oil temperature in the hydraulic circuit can be reduced and kept at a normal oil temperature, thereby ensuring the normal operation of the boom cylinder. Compared with the prior art, there is no need to configure temperature monitoring, and the cost can be effectively reduced.

[0025] On the other hand, the present invention provides an excavator, which includes the boom decoupling hydraulic system of any of the above-mentioned schemes, and the excavator also includes an excavator body, a boom articulated with the excavator body, a boom articulated with the boom, and a bucket articulated with the boom, the boom cylinder body of the boom cylinder is articulated with the excavator body, the boom piston rod of the boom cylinder is articulated with the boom, the boom cylinder body of the boom cylinder is articulated with the boom, the boom piston rod of the boom cylinder is articulated with the boom, the bucket cylinder body of the bucket cylinder is articulated with the boom, and the bucket piston rod of the bucket cylinder is articulated with the bucket.

[0026] The excavator provided by the present invention has at least the following beneficial effects:

[0027] The excavator includes the above-mentioned boom decoupling hydraulic system, which can realize bucket decoupling and optimize the thermal balance of the boom decoupling hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the first partial structure of the bucket arm decoupling hydraulic system in an embodiment of the present invention (the bucket arm piston rod is in the extended position);

[0029] Figure 2 A second partial structural schematic diagram of the bucket arm decoupling hydraulic system in an embodiment of the present invention (the bucket arm piston rod is in the retracted position);

[0030] Figure 3 It is a schematic diagram of the third partial structure of the bucket arm decoupling hydraulic system in an embodiment of the present invention (the boom piston rod and the bucket piston rod are extended at the same time);

[0031] Figure 4 It is a schematic diagram of the fourth partial structure of the bucket arm decoupling hydraulic system in an embodiment of the present invention (the boom piston rod and the bucket piston rod are retracted at the same time);

[0032] Figure 5 It is a structural schematic diagram of a driving system in a bucket arm decoupling hydraulic system in an embodiment of the present invention;

[0033] Figure 6 It is another structural schematic diagram of a driving system in a bucket arm decoupling hydraulic system in an embodiment of the present invention;

[0034] Figure 7 It is another structural schematic diagram of the drive system in the boom decoupling hydraulic system in an embodiment of the present invention.

[0035] In the figure:

[0036] 1. Arm cylinder; 101. Arm with rod cavity; 102. Arm without rod cavity;

[0037] 2. Boom cylinder; 201, boom rod chamber; 202, boom rodless chamber;

[0038] 3. Bucket cylinder; 301. Bucket with rod chamber; 302. Bucket without rod chamber;

[0039] 4. Make-up oil pump; 5. Oil tank; 6. Make-up oil overflow valve; 7. First closed oil pump; 8. Second closed oil pump; 9. Flow balance valve; 10. First holding valve; 11. First pilot valve; 12. First solenoid valve; 13. Second holding valve; 14. Second pilot valve; 15. Second solenoid valve; 16. First control valve; 17. First make-up oil check valve; 18. Second make-up oil check valve; 19. First overflow valve; 20. Second overflow valve; 21. Regeneration valve; 22. First oil pump; 23. Second oil pump; 24. Second control valve; 25. Third control valve; 26. Fourth control valve; 27. Third pilot valve ; 28. The third holding valve; 29. ​​The first motor; 30. The battery; 31. The second motor; 32. The third motor; 33. The oil replenishing motor; 34. The first internal combustion engine; 35. The first generator; 36. The second internal combustion engine; 37. The second generator; 38. The rotary motor; 39. The left travel motor; 40. The right travel motor; 41. The oil replenishing circuit; 42. The first oil circuit; 43. The second oil circuit; 44. The third oil circuit; 45. The large-cavity oil circuit of the boom; 46. The small-cavity oil circuit of the boom; 47. The large-cavity oil circuit of the bucket; 48. The small-cavity oil circuit of the bucket; 49. The fourth oil circuit; 50. The fifth oil circuit; 51. The return oil circuit. DETAILED DESCRIPTION

[0040] 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.

[0041] In the description of the present invention, it should be noted that the orientations or positional relationships indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are based on the orientations or positional relationships shown in the accompanying 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" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature "above", "above" and "above" the second feature include the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature include the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0042] 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.

[0043] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0044] In the prior art, some decoupled hydraulic circuits use open pumps to supply oil, which will cause large shocks in the system and energy waste. Some decoupled hydraulic circuits use closed pumps to drive oil circulation and cooperate with accumulators to recover energy. Compared with open pumps, they can solve the problems of large shocks in the system and energy waste. However, the accumulator will overflow at high pressure when it reaches the maximum pressure, and the pipelines connected to the rod chamber and the rodless chamber will also overflow at high pressure when they reach the maximum pressure. This will generate a lot of heat and affect the thermal balance of the system. In order to avoid excessive oil temperature in the system, additional temperature monitoring is required. When abnormal temperature is detected, the hot oil in the system needs to overflow to the oil tank through the low-pressure overflow valve, and the oil in the oil tank is replenished into the system, affecting the normal operation of the oil cylinder.

[0045] In this regard, the present embodiment provides an excavator and a boom decoupling hydraulic system to solve the above-mentioned problems.

[0046] For details, please refer to Figures 1 to 4 The excavator includes a boom decoupling hydraulic system, an excavator body, a boom hinged to the excavator body, a boom hinged to the boom, and a bucket hinged to the boom. The boom decoupling hydraulic system includes a boom cylinder 1, a boom cylinder 2, and a bucket cylinder 3. The boom cylinder body of the boom cylinder 2 is hinged to the excavator body, the boom piston rod of the boom cylinder 2 is hinged to the boom, the boom cylinder body of the boom cylinder 1 is hinged to the boom, the boom piston rod of the boom cylinder 1 is hinged to the boom, the bucket cylinder body of the bucket cylinder 3 is hinged to the boom, and the bucket piston rod of the bucket cylinder 3 is hinged to the bucket. The boom can be driven to rotate by the boom cylinder 2, the boom can be driven to swing outward or retracted by the boom cylinder 1, and the bucket can be driven to rotate by the bucket cylinder 3.

[0047] Please refer to Figure 1 and Figure 2 The arm oil cylinder 1 includes an arm rod chamber 101 and an arm rodless chamber 102 with variable volumes. The arm oil cylinder 1 also includes an arm piston rod and an arm cylinder body. The arm piston rod divides the inner cavity of the arm cylinder body into the arm rod chamber 101 and the arm rodless chamber 102. The arm piston rod passes through the arm rod chamber 101 so that the cross-sectional area of ​​the arm rod chamber 101 is smaller than the cross-sectional area of ​​the arm rodless chamber 102. The arm piston rod can move in the arm cylinder body, and when the arm piston rod moves, the volumes of the arm rod chamber 101 and the arm rodless chamber 102 increase and decrease. In this embodiment, the number of the arm oil cylinder 1 is specifically one.

[0048] Please refer to Figure 3 and Figure 4 The boom cylinder 2 includes a boom rod chamber 201 and a boom rodless chamber 202 with variable volumes. The boom cylinder 2 also includes a boom piston rod and a boom cylinder body. The boom piston rod divides the inner cavity of the boom cylinder body into a boom rod chamber 201 and a boom rodless chamber 202. The boom piston rod passes through the boom rod chamber 201 so that the cross-sectional area of ​​the boom rod chamber 201 is smaller than the cross-sectional area of ​​the boom rodless chamber 202. The boom piston rod can move in the boom cylinder body, and when the boom piston rod moves, the volumes of the boom rod chamber 201 and the boom rodless chamber 202 increase and decrease. In this embodiment, the number of the boom cylinders 2 is specifically two.

[0049] Please refer to Figure 3 and Figure 4The bucket cylinder 3 includes a bucket rod chamber 301 and a bucket rodless chamber 302 with variable volumes. The bucket cylinder 3 also includes a bucket piston rod and a bucket cylinder body. The bucket piston rod divides the inner cavity of the bucket cylinder body into the bucket rod chamber 301 and the bucket rodless chamber 302. The bucket piston rod passes through the bucket rod chamber 301 so that the cross-sectional area of ​​the bucket rod chamber 301 is smaller than the cross-sectional area of ​​the bucket rodless chamber 302. The bucket piston rod can move in the bucket cylinder body, and when the bucket piston rod moves, the volumes of the bucket rod chamber 301 and the bucket rodless chamber 302 increase and decrease. In this embodiment, the number of the bucket cylinder 3 is specifically one.

[0050] Please refer to Figure 1 and Figure 2 The boom decoupling hydraulic system also includes an oil replenishment pump 4. One end of the oil replenishment pump 4 is connected to the oil tank 5, and the other end is connected to the oil replenishment oil circuit 41. The oil replenishment pump 4 can pump the oil in the oil tank 5 to the oil replenishment oil circuit 41, and supply oil to other oil circuits through the oil replenishment oil circuit 41. Among them, the oil replenishment pump 4 in this embodiment is specifically an open pump. Preferably, the boom decoupling hydraulic system also includes an oil replenishment overflow valve 6 connected to the oil replenishment oil circuit 41, and the oil replenishment overflow valve 6 is used to overflow the oil in the oil replenishment oil circuit 41 that exceeds the set pressure to the oil tank 5.

[0051] In this embodiment, the boom decoupling hydraulic system further includes a first closed oil pump 7 and a second closed oil pump 8. Among them, one end of the first closed oil pump 7 is connected to the first oil circuit 42, and the other end of the first closed oil pump 7 is connected to the second oil circuit 43, the first oil circuit 42 is connected to the boom rodless chamber 102, and the second oil circuit 43 is connected to the boom rod chamber 101, and the first closed oil pump 7 can rotate forward and reverse; one end of the second closed oil pump 8 is connected to the oil replenishment oil circuit 41, and the other end of the second closed oil pump 8 is connected to the third oil circuit 44, and the third oil circuit 44 is connected to the first oil circuit 42, and the second closed oil pump 8 can rotate forward and reverse. Specifically, in this embodiment, the first closed oil pump 7 and the second closed oil pump 8 both adopt closed metering pumps. The first closed oil pump 7 and the two oil chambers of the boom cylinder 1 constitute a hydraulic circuit. The second closed oil pump 8, the boom rodless chamber 102 and the oil replenishing circuit 41 constitute a hydraulic circuit. Compared with an open pump, the use of a closed pump can effectively reduce energy loss; and the boom cylinder 1 is supplied with oil through the first closed oil pump 7 and the second closed oil pump 8, thereby realizing the decoupling of the boom cylinder 1, thereby improving the controllability of the boom cylinder 1.

[0052] Specifically, in the present embodiment, the boom piston rod can move relative to the boom cylinder body and has an extended position and a retracted position. When the boom piston rod moves toward the extended position, the boom piston rod gradually extends outward, and the first closed oil pump 7 rotates forward and pumps the oil in the boom rod chamber 101 into the boom rodless chamber 102. However, since the cross-sectional area of ​​the boom rod chamber 101 is smaller than the cross-sectional area of ​​the boom rodless chamber 102, there is a flow difference between the boom rod chamber 101 and the boom rodless chamber 102. Therefore, the oil in the oil replenishment circuit 41 can also be pumped into the boom rodless chamber 102 at the same time by the second closed oil pump 8 to compensate for the flow difference. At this time, the second closed oil pump 8 also rotates forward. When the boom piston rod moves to the retracted position, the boom piston rod gradually retracts inward, the first closed oil pump 7 rotates in the opposite direction, and pumps a part of the oil in the boom rodless chamber 102 into the boom rod chamber 101. At the same time, the second closed oil pump 8 rotates in the opposite direction, and the second closed oil pump 8 pumps another part of the oil in the boom rodless chamber 102 to the oil replenishing circuit 41 to compensate for the flow difference.

[0053] Please refer again Figure 1 and Figure 2 The arm decoupling hydraulic system also includes a flow balancing valve 9. The flow balancing valve 9 connects the one with lower oil pressure in the first oil circuit 42 and the second oil circuit 43 to the oil replenishment circuit 41, that is, the one with lower oil pressure in the arm rod chamber 101 and the arm rodless chamber 102 is connected to the oil replenishment circuit 41. By setting the flow balancing valve 9, the oil in the arm rodless chamber 102 and the arm rod chamber 101 with lower oil pressure can be directly entered into the oil replenishment circuit 41, or the oil in the oil replenishment circuit 41 can be directly entered into the arm rodless chamber 102 and the arm rod chamber 101 with lower oil pressure. Since the temperature of the oil in the oil replenishment circuit 41 is relatively low, when the temperature of the oil in the hydraulic circuit is too high, the hot oil in the hydraulic circuit can be replaced, which can ensure the normal oil temperature in the hydraulic circuit, and thus ensure the normal operation of the arm cylinder 1; in addition, compared with the prior art, there is no need to configure temperature monitoring, which can also effectively reduce costs.

[0054] In addition, connecting the one with lower oil pressure in the first oil circuit 42 and the second oil circuit 43 to the oil replenishment circuit 41 through the flow balancing valve 9 can also effectively compensate for the flow difference between the boom rod chamber 101 and the boom rodless chamber 102.

[0055] It should be noted that the direction of movement of the boom piston rod and the direction of the load force on the boom piston rod jointly determine the oil pressure in the boom rodless chamber 102 and the boom rod chamber 101. When the direction of the load force is consistent with the direction of movement of the boom piston rod, the load force is a negative load, and when the direction of the load force is opposite to the direction of movement of the boom piston rod, the load force is a positive load. When the boom piston rod moves to the retracted position, the boom swings outward. If the boom piston rod is subjected to a negative load, the oil pressure in the boom rodless chamber 102 is greater than the oil pressure in the boom rod chamber 101, and the flow balance valve 9 connects the oil replenishment circuit 41 and the second oil circuit 43; if the boom piston rod is subjected to a positive load, the oil pressure in the boom rod chamber 101 is greater than the oil pressure in the boom rodless chamber 102, and the flow balance valve 9 connects the oil replenishment circuit 41 and the first oil circuit 42. When the boom piston rod moves to the extended position, the boom is retracted. If the boom piston rod is subjected to a negative load, the oil pressure in the boom rodless chamber 102 will be lower than the oil pressure in the boom rod chamber 101, and the flow balancing valve 9 connects the oil replenishing circuit 41 and the first oil circuit 42. If the boom piston rod is subjected to a positive load, the oil pressure in the boom rodless chamber 102 will be higher than the oil pressure in the boom rod chamber 101, and the flow balancing valve 9 connects the oil replenishing circuit 41 and the second oil circuit 43.

[0056] In this embodiment, the flow balancing valve 9 includes a P1 interface, an A 11 Interface and A 12 Interface, where P1 interface is connected to the oil replenishment line 41, A 11 The interface is connected to the first oil circuit 42, A 12 The flow balance valve 9 has a first left position and a first right position. When the flow balance valve 9 is in the first left position, the flow balance valve 9 makes the P1 interface and the A interface communicate with each other. 12 The interface is connected and A 11 The interface is disconnected, so that the oil supply oil circuit 41 is connected to the second oil circuit 43, and the oil supply oil circuit 41 is disconnected from the first oil circuit 42; when the flow balance valve 9 is in the first right position, the flow balance valve 9 makes the P1 interface and A 11 The interface is connected and A 12 The interface is disconnected, so that the oil replenishment circuit 41 is connected to the first oil circuit 42, and the oil replenishment circuit 41 is disconnected from the second oil circuit 43. Preferably, the flow balancing valve 9 also has a first middle position. When the flow balancing valve 9 is in the first middle position, the P1 interface is disconnected, the A 11 The interface is disconnected and A 12 The interface is disconnected, thereby causing the oil replenishment circuit 41 to be disconnected from the first oil circuit 42 and the second oil circuit 43 at the same time.

[0057] In this embodiment, the flow balancing valve 9 is a hydraulically controlled valve, and the flow balancing valve 9 has a first hydraulic control end and a second hydraulic control end, the first hydraulic control end is connected to the first oil circuit 42, and the second hydraulic control end is connected to the second oil circuit 43, the first hydraulic control end and the second hydraulic control end are respectively located on both sides of the valve core of the flow balancing valve 9, and the oil of the first hydraulic control end and the second hydraulic control end directly acts on the valve core of the flow balancing valve 9, and the force of the oil of the first hydraulic control end acting on the valve core of the flow balancing valve 9 and the force of the oil of the second hydraulic control end acting on the valve core of the flow balancing valve 9 are compared to determine the stop position of the valve core of the flow balancing valve 9. Specifically, when the oil pressure of the first hydraulic control end is greater than the oil pressure of the second hydraulic control end, the flow balancing valve 9 is located in the first left position; when the oil pressure of the first hydraulic control end is less than the oil pressure of the second hydraulic control end, the flow balancing valve 9 is located in the first right position; when the oil pressure of the first hydraulic control end is equal to the oil pressure of the second hydraulic control end, the flow balancing valve 9 is located in the first middle position. In other embodiments, the flow balancing valve 9 can also be an electrically controlled valve.

[0058] Optionally, see Figure 1 and Figure 2The boom decoupling hydraulic system also includes a first holding valve 10 and a first pilot valve 11. The first holding valve 10 has a first pump side interface and a first cylinder side interface. The first holding valve 10 is connected in series to the first oil circuit 42 through the first pump side interface and the first cylinder side interface, and the first cylinder side interface is close to the boom rodless chamber 102 relative to the first pump side interface. The first holding valve 10 has a first open state and a first closed state. When the first holding valve 10 is in the first open state, the first pump side interface and the first cylinder side interface are connected. When the first holding valve 10 is in the first closed state, the first pump side interface and the first cylinder side interface are disconnected. When the first holding valve 10 is in the first closed state: when the oil pressure at the first pump side interface exceeds the first set value of the oil pressure at the first cylinder side interface, the first holding valve 10 can be switched to the first open state under the drive of the oil pressure difference, or the first holding valve 10 is controlled to switch to the first open state by the first pilot valve 11. By setting the first holding valve 10, when the first holding valve 10 is closed, the position of the boom piston rod can be stabilized, thereby maintaining the boom position stable; when the first holding valve 10 is in the first closed state, if it is necessary to supply oil to the boom rodless chamber 102, when the oil pressure of the first pump side interface exceeds the first set value of the oil pressure of the first cylinder side interface, the first holding valve 10 can be driven by the oil pressure difference to switch to the first open state by itself without affecting the oil supply; if the oil pressure of the first pump side interface does not exceed the first set value of the oil pressure of the first cylinder side interface, the first holding valve 10 can be controlled to switch to the first open state by the first pilot valve 11; when the first holding valve 10 is in the first closed state, if it is necessary to discharge the oil in the boom rodless chamber 102, the first holding valve 10 can be controlled to switch to the first open state by the first pilot valve 11.

[0059] Specifically, the first holding valve 10 includes a first holding valve housing and a first holding valve spool, a first pump side interface and a first cylinder side interface are arranged in the first holding valve housing, the first pump side interface and the first cylinder side interface are connected in series to the first oil circuit 42, the first holding valve spool is slidably located in the first holding valve housing, the first holding valve spool divides the inner cavity of the first holding valve housing into a first spring cavity and a first oil cavity, the first holding valve spool can slide relative to the first holding valve housing so that the first holding valve 10 has a first open state and a first closed state, when the first holding valve 10 is in the first closed state, the first holding valve spool can further divide the first oil cavity into a first cavity and a second cavity which are not connected to each other, wherein the first cylinder side interface is always connected to the first cavity, and the first pump side interface is always connected to the second cavity, at this time, since the first cavity and the second cavity are separated, the first oil circuit 42 is disconnected; when the first holding valve 10 is in the first open state, the first cavity and the second cavity are connected, at this time, the first oil circuit 42 is connected.

[0060] Furthermore, the first holding valve 10 also includes a first holding valve spring, and the first holding valve housing is also provided with a first control interface and a second control interface. The first holding valve spring is located in the first spring chamber and the two ends of the first holding valve spring are respectively abutted against the first holding valve core and the first holding valve housing, the first control interface is always connected to the first chamber, and the second control interface is always connected to the first spring chamber. The first holding valve spring and the hydraulic oil in the first spring chamber give the first holding valve core a force F1 to move toward the first chamber side, and the hydraulic oil in the first chamber and the hydraulic oil in the second chamber give the first holding valve core a force F2 to move toward the first spring chamber side. The position of the first holding valve core is determined by comparing the sizes of F1 and F2, thereby determining the state of the first holding valve 10.

[0061] In this embodiment, the first pilot valve 11 is a two-position three-way valve, and the first pilot valve 11 can make the first control interface and the second control interface communicate with each other. At this time, the oil pressure in the first chamber and the first spring chamber is equal, but the action area of ​​the oil in the first chamber and the first holding valve core is smaller than the action area of ​​the oil in the first spring chamber and the first holding valve core, and the first holding valve spring in the first spring chamber also gives the first holding valve core a force, which can make the first holding valve core move toward the first chamber side, thereby making the first holding valve 10 in the first closed state, ensuring the first oil circuit 42 is closed stably. The first pilot valve 11 can also make the second control interface and the oil tank 5 communicate with each other. At this time, the position of the first holding valve core is determined by comparing the sizes of F1 and F2, and when F1 is less than F2, the first holding valve spring is compressed, which can make the first holding valve core move toward the first spring chamber side, thereby making the first holding valve 10 in the first open state, so that the first oil circuit 42 is opened.

[0062] Specifically, the first pilot valve 11 is a hydraulically controlled reversing valve, and the working position of the first pilot valve 11 can be controlled by the on-off of the signal oil source of the hydraulically controlled reversing valve, so that the first control interface and the second control interface can be connected, or the second control interface and the oil tank 5 can be connected and the first control interface is disconnected. In other embodiments, the first pilot valve 11 can also be replaced by an electrically controlled reversing valve. Among them, in this embodiment, the boom decoupling hydraulic system also includes a first solenoid valve 12 for controlling the connection and disconnection of the oil circuit of the hydraulic control end of the first pilot valve 11, so the on-off of the signal oil source of the first pilot valve 11 can be controlled by the first solenoid valve 12 to realize the switching control of the working position of the first pilot valve 11.

[0063] Optionally, see Figure 1 and Figure 2The boom decoupling hydraulic system also includes a second holding valve 13 and a second pilot valve 14. The second holding valve 13 has a second pump side interface and a second cylinder side interface. The second holding valve 13 is connected in series to the second oil circuit 43 through the second pump side interface and the second cylinder side interface, and the second cylinder side interface has a rod chamber 101 close to the boom relative to the second pump side interface. The second holding valve 13 has a second open state and a second closed state. When the second holding valve 13 is in the second open state, the second pump side interface and the second cylinder side interface are connected. When the second holding valve 13 is in the second closed state, the second pump side interface and the second cylinder side interface are disconnected. When the second holding valve 13 is in the second closed state, when the oil pressure at the second pump side interface exceeds the second set value of the oil pressure at the second cylinder side interface, the second holding valve 13 is switched to the second open state under the drive of the oil pressure difference, or the second holding valve 13 is switched to the second open state by controlling the second pilot valve 14. By setting the second holding valve 13, when the second holding valve 13 is closed, the position of the boom piston rod can be stabilized, thereby maintaining the boom position stable; when the second holding valve 13 is in the second closed state, if it is necessary to supply oil to the boom rod chamber 101, when the oil pressure of the second pump side interface exceeds the second set value of the oil pressure of the second cylinder side interface, under the action of the oil pressure, the second holding valve 13 can be switched to the second open state by itself without affecting the oil supply; if the oil pressure of the second pump side interface does not exceed the second set value of the oil pressure of the second cylinder side interface, the second holding valve 13 can be controlled to switch to the second open state by the second pilot valve 14; when the second holding valve 13 is in the second closed state, if it is necessary to discharge the oil in the boom rod chamber 101, the second holding valve 13 can be controlled to switch to the second open state by the second pilot valve 14.

[0064] Specifically, the second holding valve 13 includes a second holding valve housing and a second holding valve spool, a second pump side interface and a second cylinder side interface are arranged in the second holding valve housing, the second pump side interface and the second cylinder side interface are connected in series to the second oil circuit 43, the second holding valve spool is slidably located in the second holding valve housing, the second holding valve spool divides the inner cavity of the second holding valve housing into a second spring cavity and a second oil cavity, the second holding valve spool can slide relative to the second holding valve housing so that the second holding valve 13 has a second open state and a second closed state, when the second holding valve 13 is in the second closed state, the second holding valve spool can further divide the second oil cavity into a third cavity and a fourth cavity that are not connected to each other, wherein the second cylinder side interface is always connected to the third cavity, and the second pump side interface is always connected to the fourth cavity, at this time, since the third cavity and the fourth cavity are separated, the second oil circuit 43 is disconnected; when the second holding valve 13 is in the second open state, the third cavity and the fourth cavity are connected, at this time, the second oil circuit 43 is connected.

[0065] Furthermore, the second holding valve 13 also includes a second holding valve spring, and the second holding valve housing is also provided with a third control interface and a fourth control interface. The second holding valve spring is located in the second spring chamber and the two ends of the second holding valve spring are respectively abutted against the second holding valve spool and the second holding valve housing, the third control interface is always connected to the third chamber, and the fourth control interface is always connected to the second spring chamber. The second holding valve spring and the hydraulic oil in the second spring chamber give the second holding valve spool a force F3 to move toward the third chamber side, and the hydraulic oil in the third chamber and the hydraulic oil in the fourth chamber give the second holding valve spool a force F4 to move toward the second spring chamber side. The sizes of F3 and F4 are compared to determine the position of the second holding valve spool, and then determine the state of the second holding valve 13.

[0066] In this embodiment, the second pilot valve 14 is a two-position three-way valve, and the second pilot valve 14 can make the third control interface and the fourth control interface communicate. At this time, the oil pressure in the third chamber and the second spring chamber is equal, but the action area between the oil in the third chamber and the second holding valve core is smaller than the action area between the oil in the second spring chamber and the second holding valve core, and the second holding valve spring in the second spring chamber also gives the second holding valve core a force, which can make the second holding valve core move toward the third chamber side, thereby making the second holding valve 13 in the second closed state, ensuring the second oil circuit 43 is closed stably. The second pilot valve 14 can also make the fourth control interface and the oil tank 5 communicate. At this time, the position of the second holding valve core is determined by comparing the sizes of F3 and F4. When F3 is less than F4, the second holding valve spring is compressed, which can make the second holding valve core move toward the second spring chamber side, thereby making the second holding valve 13 in the second open state, so that the second oil circuit 43 is opened.

[0067] Specifically, the second pilot valve 14 is a hydraulically controlled reversing valve, and the working position of the second pilot valve 14 can be controlled by the on-off of the signal oil source of the hydraulically controlled reversing valve, so that the third control interface and the fourth control interface can be connected, or the fourth control interface and the oil tank 5 can be connected and the third control interface is disconnected. In other embodiments, the second pilot valve 14 can also be replaced by an electrically controlled reversing valve. Among them, in this embodiment, the boom decoupling hydraulic system also includes a second solenoid valve 15 for controlling the connection and disconnection of the oil circuit of the hydraulic control end of the second pilot valve 14, so the on-off of the signal oil source of the second pilot valve 14 can be controlled by the second solenoid valve 15 to realize the switching control of the working position of the second pilot valve 14.

[0068] Optionally, see Figure 1 and Figure 2The boom decoupling hydraulic system also includes a first control valve 16, which is arranged in the first oil circuit 42, and the first control valve 16 is located between the first holding valve 10 and the first closed oil pump 7, and the first control valve 16 is used to open or close the first oil circuit 42; the first control valve 16 is configured to open the first oil circuit 42 when the first pilot valve 11 controls the first holding valve 10 to switch to the first open state and the second pilot valve 14 switches to the second open state under the drive of the oil pressure difference, or when the first pilot valve 11 switches to the first open state under the drive of the oil pressure difference and the second pilot valve 14 controls the second holding valve 13 to switch to the second open state. It is understandable that when the boom piston rod of the boom cylinder 1 is extended or retracted, the oil in the two chambers of the boom cylinder 1 needs to flow in and out, and the first holding valve 10 and the second holding valve 13 must be in the open state at the same time. One of the holding valves can be opened by the differential pressure between the pump side interface and the cylinder side interface being greater than the set value, and the other needs to be opened by the pilot valve control, so that the first control valve 16 is opened synchronously. When the position of the boom piston rod needs to remain unchanged, the first holding valve 10 and the second holding valve 13 are both kept closed. At this time, the first control valve 16 disconnects the first oil circuit 42, which can further ensure that the first oil circuit 42 is stably disconnected and improve the stability of the boom piston rod position.

[0069] Specifically, in this embodiment, the first control valve 16 is also a hydraulically controlled valve, and the valve core of the first control valve 16 can move in the valve housing of the first control valve 16 and has a second left position, a second middle position, and a second right position. When the first control valve 16 is in the second left position and the second right position, the first control valve 16 connects the first oil circuit 42, and when the first control valve 16 is in the second middle position, the first control valve 16 disconnects the first oil circuit 42. The first control valve 16 has at least a P2 interface, an A 21 Interface and A 22 Interface, A 21 Interface and A 22 The interfaces are connected to the side of the first oil circuit 42 near the first closed oil pump 7, and the P2 interface is connected to the side of the first oil circuit 42 near the bucket cylinder 1. When the first control valve 16 is in the second left position, A 21 The interface is connected to the P2 interface, and A 22 The interface is disconnected, so that the first oil circuit 42 is connected; when the first control valve 16 is in the second right position, A 22 The interface is connected to the P2 interface, and A 21 The interface is disconnected, and the first oil circuit 42 is also connected; when the first control valve 16 is in the second middle position, the P2 interface, A 21 Interface and A 22 The interfaces are all disconnected, so that the first oil circuit 42 is disconnected.

[0070] The first control valve 16 includes a third hydraulic control end and a fourth hydraulic control end. The first solenoid valve 12 is also used to control the connection and disconnection of the oil circuit of the third hydraulic control end. The second solenoid valve 15 is also used to control the connection and disconnection of the oil circuit of the fourth hydraulic control end. The third hydraulic control end and the fourth hydraulic control end are respectively located on both sides of the valve core of the first control valve 16, and the oil of the third hydraulic control end and the fourth hydraulic control end directly acts on the valve core of the first control valve 16. The force of the oil of the third hydraulic control end acting on the valve core of the first control valve 16 and the force of the oil of the fourth hydraulic control end acting on the valve core of the first control valve 16 are compared to determine the stop position of the valve core of the first control valve 16.

[0071] Optionally, the boom decoupling hydraulic system also includes a first oil replenishment check valve 17 and a second oil replenishment check valve 18, the first oil replenishment check valve 17 is connected between the oil replenishment oil circuit 41 and the first oil circuit 42, and the first oil replenishment check valve 17 only allows oil to flow from the oil replenishment oil circuit 41 to the first oil circuit 42; the second oil replenishment check valve 18 is connected between the oil replenishment oil circuit 41 and the second oil circuit 43, and the second oil replenishment check valve 18 only allows oil to flow from the oil replenishment oil circuit 41 to the second oil circuit 43. By setting the first oil replenishment check valve 17, when the oil pressure in the arm rodless chamber 102 is low, the oil can be replenished to the arm rodless chamber 102 through the oil replenishment oil circuit 41. By setting the second oil replenishment check valve 18, when the oil pressure in the arm rod chamber 101 is low, the oil can be replenished to the arm rod chamber 101 through the oil replenishment oil circuit 41, so as to further balance the flow difference between the arm rod chamber 101 and the arm rodless chamber 102. Specifically, the connection between the first oil replenishment check valve 17 and the first oil circuit 42 is located between the first holding valve 10 and the arm cylinder 1.

[0072] Optionally, the boom decoupling hydraulic system further includes a first overflow valve 19 and a second overflow valve 20, wherein the first overflow valve 19 is connected between the oil replenishment circuit 41 and the first oil circuit 42, and the first overflow valve 19 only allows oil to overflow from the boom rodless chamber 102 to the oil replenishment circuit 41 through the first oil circuit 42; the second overflow valve 20 is connected between the oil replenishment circuit 41 and the second oil circuit 43, and the second overflow valve 20 only allows oil to overflow from the boom rod chamber 101 to the oil replenishment circuit 41 through the second oil circuit 43. By providing the first overflow valve 19 and the second overflow valve 20, the oil pressure in the boom rod chamber 101 and the boom rodless chamber 102 can be effectively balanced.

[0073] Optionally, the boom decoupling hydraulic system further includes a regeneration valve 21, which is configured to connect the first oil circuit 42 and the second oil circuit 43, or disconnect the first oil circuit 42 and the second oil circuit 43. Specifically, the connection between the regeneration valve 21 and the first oil circuit 42 is located between the first control valve 16 and the first holding valve 10. When the regeneration valve 21 is opened, the oil can flow directly between the boom rodless chamber 102 and the boom rod chamber 101, and flow from the side with high pressure to the side with low pressure, so that the boom piston rod can move quickly.

[0074] Please refer to Figure 3 and Figure 4 , the boom decoupling hydraulic system also includes a first oil pump 22 and a second oil pump 23. The first oil pump 22 is configured to supply oil to one of the boom rod chamber 201 and the boom rodless chamber 202, and one of the bucket rod chamber 301 and the bucket rodless chamber 302; the second oil pump 23 is configured to selectively supply oil to one of the bucket rodless chamber 302, the boom rod chamber 201 and the boom rodless chamber 202. In this embodiment, the boom cylinder 2 and the bucket cylinder 3 are compounded, and the boom cylinder 1 is decoupled. Compared with the hydraulic system in which the bucket cylinder 3, the boom cylinder 1 and the boom cylinder 2 are compounded as a whole, the flexibility of the control of the boom cylinder 1 can be improved, and the controllability of the whole machine can be improved. In addition, the first oil pump 22 supplies oil to the boom cylinder 2 and the bucket cylinder 3 at the same time, and the second oil pump 23 supplies oil to the boom cylinder 2, or supplies oil to the bucket rodless chamber 302 of the bucket cylinder 3, which can reduce the load of the first oil pump 22 and the power demand for the first oil pump 22; at the same time, it can also take into account the working conditions of rapid extension and retraction of the boom piston rod of the boom cylinder 2 and rapid extension of the bucket piston rod of the bucket cylinder 3, which require a large amount of oil. In this embodiment, the first oil pump 22 and the second oil pump 23 are specifically open pumps.

[0075] Optionally, in this embodiment, the boom decoupling hydraulic system further includes a second control valve 24 , a third control valve 25 and a fourth control valve 26 . Among them, the second control valve 24 can make the output end of the first oil pump 22 communicate with one of the boom rod chamber 201 and the boom rodless chamber 202, and make the oil tank 5 communicate with the other of the boom rod chamber 201 and the boom rodless chamber 202; the third control valve 25 can make the output end of the first oil pump 22 communicate with one of the bucket rod chamber 301 and the bucket rodless chamber 302, and make the oil tank 5 communicate with the other of the bucket rod chamber 301 and the bucket rodless chamber 302; the fourth control valve 26 and the second control valve 24 cooperate to make the output end of the second oil pump 23 communicate with one of the boom rod chamber 201 and the boom rodless chamber 202, and make the oil tank 5 communicate with the other of the boom rod chamber 201 and the boom rodless chamber 202, and the fourth control valve 26 can also make the output end of the second oil pump 23 communicate with the bucket rodless chamber 302. With such arrangement, the first oil pump 22 can supply oil to the bucket cylinder 3 and the boom cylinder 2 respectively under the control of the second control valve 24 and the third control valve 25, and the second oil pump 23 can supply oil to the bucket rodless chamber 302 under the sole control of the fourth control valve 26, or supply oil to the boom rod chamber 201 or the boom rodless chamber 202 in cooperation with the fourth control valve 26 and the second control valve 24, thereby meeting the different oil volume requirements of the boom and the bucket.

[0076] Specifically, in this embodiment, the boom decoupling hydraulic system also includes a boom large chamber oil circuit 45 connected to the boom rodless chamber 202, a boom small chamber oil circuit 46 connected to the boom rod chamber 201, a bucket large chamber oil circuit 47 connected to the bucket rodless chamber 302, a bucket small chamber oil circuit 48 connected to the bucket rod chamber 301, a fourth oil circuit 49, a fifth oil circuit 50 and an oil return circuit 51 connected to the oil tank 5. Among them, the fourth oil circuit 49 is connected to the output end of the first oil pump 22; the fifth oil circuit 50 is connected to the output end of the second oil pump 23, and the second control valve 24 is simultaneously connected to the return oil circuit 51, the fourth oil circuit 49, the boom large cavity oil circuit 45 and the boom small cavity oil circuit 46; the third control valve 25 is simultaneously connected to the return oil circuit 51, the fourth oil circuit 49, the bucket large cavity oil circuit 47 and the bucket small cavity oil circuit 48; the fourth control valve 26 is simultaneously connected to the return oil circuit 51, the fifth oil circuit 50, the boom large cavity oil circuit 45, the boom small cavity oil circuit 46 and the bucket large cavity oil circuit 47.

[0077] The second control valve 24 can connect the fourth oil circuit 49 with one of the boom large cavity oil circuit 45 and the boom small cavity oil circuit 46, and connect the return oil circuit 51 with the other of the boom large cavity oil circuit 45 and the boom small cavity oil circuit 46. Specifically, the second control valve 24 includes at least a P3 interface, an A 31 Interface, A 32 Interface and T1 interface, P3 interface connects to the fourth oil line 49, A31 Interface connection boom large cavity oil circuit 45, A 32 The interface is connected to the boom small chamber oil circuit 46, the T1 interface is connected to the return oil circuit 51, and the second control valve 24 has a third left position and a third right position, such as Figure 3 As shown, when the second control valve 24 is in the third right position, the P3 interface is connected to the A 31 Interface connectivity, A 32 The interface is connected with the T1 interface, so that the fourth oil circuit 49 is connected with the boom large cavity oil circuit 45, and the return oil circuit 51 is connected with the boom small cavity oil circuit 46. A part of the oil pumped by the first oil pump 22 can be pumped to the boom rodless cavity 202 through the second control valve 24, and the oil in the boom rod cavity 201 is delivered to the oil tank 5 through the second control valve 24. Figure 4 As shown, when the second control valve 24 is in the third left position, the P3 interface is connected to the A 32 Interface connectivity, A 31 The interface is connected with the T1 interface, so that the fourth oil circuit 49 is connected with the small chamber oil circuit 46 of the boom, and the return oil circuit 51 is connected with the large chamber oil circuit 45 of the boom. A part of the oil pumped by the first oil pump 22 can be pumped to the boom rod chamber 201 through the second control valve 24, and the oil in the boom rodless chamber 202 is delivered to the oil tank 5 through the second control valve 24.

[0078] The third control valve 25 can connect the fourth oil circuit 49 with one of the bucket large cavity oil circuit 47 and the bucket small cavity oil circuit 48, and connect the return oil circuit 51 with the other of the bucket large cavity oil circuit 47 and the bucket small cavity oil circuit 48. Specifically, the third control valve 25 includes at least a P4 interface, an A 41 Interface, A 42 Interface and T2 interface, P4 interface connects to the fourth oil circuit 49, A 41 Interface connection bucket large cavity oil circuit 47, A 42 The interface is connected to the bucket small chamber oil circuit 48, the T2 interface is connected to the return oil circuit 51, and the third control valve 25 has a fourth left position and a fourth right position, such as Figure 3 As shown, when the third control valve 25 is in the fourth left position, the P4 interface is connected to the A 41 Interface connectivity, A 42 The interface is connected to the T2 interface, so that the fourth oil circuit 49 is connected to the bucket large chamber oil circuit 47, and the return oil circuit 51 is connected to the bucket small chamber oil circuit 48. A part of the oil pumped by the first oil pump 22 can be pumped to the bucket rodless chamber 302 through the third control valve 25, and the oil in the bucket rod chamber 301 is delivered to the oil tank 5 through the third control valve 25. Figure 4 As shown, when the third control valve 25 is in the fourth right position, the P4 interface is connected to the A 42 Interface connectivity, A 41The interface is connected with the T2 interface, so that the fourth oil circuit 49 is connected with the bucket small chamber oil circuit 48, and the return oil circuit 51 is connected with the bucket large chamber oil circuit 47. A part of the oil pumped by the first oil pump 22 can be pumped to the bucket rod chamber 301 through the third control valve 25, and the oil in the bucket rodless chamber 302 is delivered to the oil tank 5 through the third control valve 25.

[0079] The fourth control valve 26 can make the fifth oil circuit 50 communicate with the P4 interface of the second control valve 24, or the fourth control valve 26 can make the fifth oil circuit 50 communicate with the bucket large cavity oil circuit 47. Specifically, the fourth control valve 26 includes at least the P5 interface, A 51 Interface and A 52 Interface, P5 interface connects to the fifth oil circuit 50, A 51 Interface connection P4 interface, A 52 The interface is connected to the bucket large cavity oil circuit 47, and the fourth control valve 26 has a fifth left position and a fifth right position, such as Figure 4 As shown, when the fourth control valve 26 is in the fifth right position, the P5 interface is connected to the A 51 The interface is connected so that the oil supplied by the second oil pump 23 is delivered to the input end of the second control valve 24, and can be delivered to the boom rodless chamber 202 or the boom rod chamber 201 through the second control valve 24; Figure 3 As shown, when the fourth control valve 26 is in the fifth left position, the P5 interface is connected to the A 52 Interface connectivity, A 51 The interface is disconnected, so that the oil supplied by the second oil pump 23 is delivered to the bucket rodless chamber 302 .

[0080] In this embodiment, the second control valve 24, the third control valve 25 and the fourth control valve 26 are all solenoid valves. In other embodiments, the second control valve 24, the third control valve 25 and the fourth control valve 26 can also be hydraulically controlled valves as needed.

[0081] Optionally, the arm decoupling hydraulic system further includes a third pilot valve 27 and a third holding valve 28 provided in the bucket large cavity oil circuit 47, and the third holding valve 28 is used to control the connection and disconnection of the bucket large cavity oil circuit 47. The structure of the third holding valve 28 is the same as that of the first holding valve 10, which will not be described in detail here. The third pilot valve 27 can be a solenoid valve, and is used to control the connection between the first control interface and the second control interface of the third pilot valve 27, or to connect the second control interface to the oil tank 5 and disconnect the first control interface.

[0082] Optionally, see Figure 1 , Figure 2 as well as Figures 5 to 7The arm decoupling hydraulic system also includes a first motor 29 and a battery 30. The first motor 29 can rotate forward and reverse. The battery 30 is electrically connected to the first motor 29. The first motor 29 is also connected to the first closed oil pump 7 and the second closed oil pump 8 in a transmission manner, and the first motor 29 is used to drive the first closed oil pump 7 and the second closed oil pump 8 to rotate simultaneously. In this way, the first motor 29 can simultaneously drive the first closed oil pump 7 and the second closed oil pump 8 to work, so that the arm cylinder 1 can work, and the speed of the arm piston rod of the arm cylinder 1 can be controlled by controlling the speed of the first motor 29; when the arm piston rod is retracted, the arm can be lowered by its own weight, and the first closed oil pump 7 and / or the second closed oil pump 8 can drive the first motor 29 to reverse, which can generate electricity and store it in the battery 30, so as to realize the recycling of system energy.

[0083] Optionally, see Figure 3 , Figure 4 and Figure 7 The arm decoupling hydraulic system also includes a first internal combustion engine 34, which is simultaneously connected to the first oil pump 22, the second oil pump 23 and the supplementary oil pump 4, and is used to simultaneously drive the first oil pump 22, the second oil pump 23 and the supplementary oil pump 4 to rotate. In this way, the battery 30 can provide a motor to drive the first motor 29, and the first internal combustion engine 34 can provide power to simultaneously drive the second motor 31, the third motor 32 and the supplementary oil motor 33, so that the arm decoupling hydraulic system can adopt a hybrid drive system. Preferably, the arm decoupling hydraulic system also includes a first generator 35 connected to the first internal combustion engine 34, the first generator 35 is electrically connected to the battery 30, and the first internal combustion engine 34 also drives the first generator 35 to operate and generate electricity and store it in the battery 30.

[0084] As an alternative, see Figure 5 and Figure 6 The arm decoupling hydraulic system further includes a second motor 31, a third motor 32 and an oil replenishment motor 33. The second motor 31 is connected to the first oil pump 22 by transmission, and the second motor 31 is used to drive the first oil pump 22 to rotate. The third motor 32 is connected to the second oil pump 23 by transmission, and the third motor 32 is used to drive the second oil pump 23 to rotate. The oil replenishment motor 33 is connected to the oil replenishment pump 4 by transmission, and the oil replenishment motor 33 is used to drive the oil replenishment pump 4 to rotate. The battery 30 is electrically connected to the second motor 31, the third motor 32 and the oil replenishment motor 33 respectively. At this time, the battery 30 provides power to drive the first motor 29, the second motor 31, the third motor 32 and the oil replenishment motor 33 to work, as shown in FIG. Figure 5 As shown, the boom decoupling hydraulic system can be driven by a pure electric drive system, or as Figure 6As shown, the arm decoupling hydraulic system can also be driven by an extended-range drive system. When driven by an extended-range drive system, the arm decoupling hydraulic system also includes a second internal combustion engine 36, and a second generator 37 connected to the second internal combustion engine 36, the second generator 37 is electrically connected to the battery 30, and the second internal combustion engine 36 drives the second generator 37 to operate and generate electricity and store it in the battery 30.

[0085] Optionally, the drive system further includes a slewing motor 38, a left travel motor 39 and a right travel motor 40. The slewing motor 38 is used to drive the slewing mechanism of the excavator, and the left travel motor 39 and the right travel motor 40 are used to drive the left travel mechanism and the right travel mechanism of the excavator, respectively. Such an arrangement can decouple the slewing operation, the left travel control operation and the right travel control operation of the excavator. Among them, the battery 30 also supplies power to the slewing motor 38, the left travel motor 39 and the right travel motor 40, respectively.

[0086] 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, 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 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 boom decoupling hydraulic system, comprising a boom cylinder (1), a boom cylinder (2) and a bucket cylinder (3), wherein the boom cylinder (1) comprises a boom rod chamber (101) and a boom rodless chamber (102) with variable volumes, the boom cylinder (2) comprises a boom rod chamber (201) and a boom rodless chamber (202) with variable volumes, and the bucket cylinder (3) comprises a bucket rod chamber (301) and a bucket rodless chamber (302) with variable volumes, characterized in that: The arm decoupling hydraulic system further comprises: An oil replenishment pump (4), one end of the oil replenishment pump (4) being connected to the oil tank (5) and the other end of the oil replenishment pump (4) being connected to the oil replenishment circuit (41); A first closed oil pump (7), one end of which is connected to the first oil circuit (42) and the other end of which is connected to the second oil circuit (43), the first oil circuit (42) being connected to the boom rodless chamber (102), the second oil circuit (43) being connected to the boom rod chamber (101), the first closed oil pump (7) being capable of forward and reverse rotation; A second closed oil pump (8), one end of which is connected to the oil replenishment oil circuit (41), and the other end of which is connected to a third oil circuit (44), wherein the third oil circuit (44) is connected to the first oil circuit (42), and the second closed oil pump (8) is capable of forward and reverse rotation; a flow balancing valve (9), wherein the flow balancing valve (9) connects the one with the smaller oil pressure between the first oil circuit (42) and the second oil circuit (43) to the oil replenishment circuit (41); A first oil pump (22) is configured to supply oil to one of the boom rod chamber (201) and the boom rodless chamber (202), and one of the bucket rod chamber (301) and the bucket rodless chamber (302); The second oil pump (23) is configured to selectively supply oil to one of the bucket rodless chamber (302), the boom rod chamber (201) and the boom rodless chamber (202).

2. The boom decoupling hydraulic system according to claim 1, characterized in that: The boom decoupling hydraulic system further comprises a regeneration valve (21), wherein the regeneration valve (21) is configured to connect the first oil circuit (42) and the second oil circuit (43) to each other, or to disconnect the first oil circuit (42) and the second oil circuit (43) from each other.

3. The boom decoupling hydraulic system according to claim 1, characterized in that: The boom decoupling hydraulic system further comprises a first holding valve (10) and a first pilot valve (11), wherein the first holding valve (10) has a first pump side interface and a first cylinder side interface, wherein the first holding valve (10) is connected in series to the first oil circuit (42) via the first pump side interface and the first cylinder side interface, and the first cylinder side interface is closer to the boom rodless chamber (102) relative to the first pump side interface, and the first holding valve (10) has a first open state and a first closed state, wherein when the first holding valve (10) is in the first open state, the first pump side interface and the first cylinder side interface are connected, and when the first holding valve (10) is in the first closed state, the first pump side interface and the first cylinder side interface are disconnected; When the first holding valve (10) is in the first closed state: the oil pressure at the first pump side interface exceeds the first set value of the oil pressure at the first cylinder side interface, so that the first holding valve (10) is switched to the first open state under the drive of the oil pressure difference, or the first pilot valve (11) controls the first holding valve (10) to switch to the first open state.

4. The boom decoupling hydraulic system according to claim 3, characterized in that: The boom decoupling hydraulic system further comprises a second holding valve (13) and a second pilot valve (14), wherein the second holding valve (13) has a second pump side interface and a second cylinder side interface, wherein the second holding valve (13) is connected in series to the second oil circuit (43) via the second pump side interface and the second cylinder side interface, and the second cylinder side interface has a rod cavity (101) near the boom relative to the second pump side interface, and the second holding valve (13) has a second open state and a second closed state, wherein when the second holding valve (13) is in the second open state, the second pump side interface and the second cylinder side interface are connected, and when the second holding valve (13) is in the second closed state, the second pump side interface and the second cylinder side interface are disconnected; When the second holding valve (13) is in the second closed state, when the oil pressure at the second pump side interface exceeds the second set value of the oil pressure at the second cylinder side interface, the second holding valve (13) is driven by the oil pressure difference to switch to the second open state, or the second pilot valve (14) controls the second holding valve (13) to switch to the second open state.

5. The arm decoupling hydraulic system according to claim 4, characterized in that: The boom decoupling hydraulic system further comprises a first control valve (16), the first control valve (16) being arranged in the first oil circuit (42), and the first control valve (16) being located between the first holding valve (10) and the first closed oil pump (7), the first control valve (16) being used to open or close the first oil circuit (42); The first control valve (16) is configured to open the first oil passage (42) when the first pilot valve (11) controls the first holding valve (10) to switch to the first open state and the second holding valve (13) switches to the second open state under the drive of the oil pressure difference, or when the first pilot valve (11) switches to the first open state under the drive of the oil pressure difference and the second pilot valve (14) controls the second holding valve (13) to switch to the second open state.

6. The arm decoupling hydraulic system according to claim 3, characterized in that: The boom decoupling hydraulic system further comprises a first oil replenishment check valve (17) and a second oil replenishment check valve (18); the first oil replenishment check valve (17) is connected between the oil replenishment oil circuit (41) and the first oil circuit (42); and the connection between the first oil replenishment check valve (17) and the first oil circuit (42) is located between the first holding valve (10) and the boom cylinder (1); the first oil replenishment check valve (17) only allows oil to flow from the oil replenishment oil circuit (41) to the first oil circuit (42); the second oil replenishment check valve (18) is connected between the oil replenishment oil circuit (41) and the second oil circuit (43); and the second oil replenishment check valve (18) only allows oil to flow from the oil replenishment oil circuit (41) to the second oil circuit (43).

7. The boom decoupling hydraulic system according to claim 3, characterized in that: The boom decoupling hydraulic system further comprises a first overflow valve (19) and a second overflow valve (20), wherein the first overflow valve (19) is connected between the oil replenishment circuit (41) and the first oil circuit (42), and the connection between the first overflow valve (19) and the first oil circuit (42) is located between the first holding valve (10) and the boom cylinder (1), and the first overflow valve (19) only allows oil to overflow from the first oil circuit (42) to the oil replenishment circuit (41); the second overflow valve (20) is connected between the oil replenishment circuit (41) and the second oil circuit (43), and the second overflow valve (20) only allows oil to overflow from the second oil circuit (43) to the oil replenishment circuit (41).

8. The arm decoupling hydraulic system according to claim 1, characterized in that: The boom decoupling hydraulic system further comprises a first motor (29) and a battery (30); the first motor (29) is capable of forward and reverse rotation; the battery (30) is electrically connected to the first motor (29); the first motor (29) is simultaneously transmission-connected to the first closed oil pump (7) and the second closed oil pump (8); and the first motor (29) is used to drive the first closed oil pump (7) and the second closed oil pump (8) to rotate simultaneously.

9. The arm decoupling hydraulic system according to claim 8, characterized in that: The arm decoupling hydraulic system further comprises a battery (30), a second motor (31), a third motor (32) and an oil replenishment motor (33); the second motor (31) is transmission-connected to the first oil pump (22); the second motor (31) is used to drive the first oil pump (22) to rotate; the third motor (32) is transmission-connected to the second oil pump (23); the third motor (32) is used to drive the second oil pump (23) to rotate; the oil replenishment motor (33) is transmission-connected to the oil replenishment pump (4); the oil replenishment motor (33) is used to drive the oil replenishment pump (4) to rotate; the battery (30) is electrically connected to the second motor (31), the third motor (32) and the oil replenishment motor (33), respectively; or, The boom decoupling hydraulic system further comprises a first internal combustion engine (34), the first internal combustion engine (34) being simultaneously connected in transmission with the first oil pump (22), the second oil pump (23) and the replenishing oil pump (4), and the first internal combustion engine (34) being used for simultaneously driving the first oil pump (22), the second oil pump (23) and the replenishing oil pump (4) to rotate.

10. An excavator, characterized in that: The excavator comprises an excavator body, a boom hinged to the excavator body, a boom hinged to the boom, and a bucket hinged to the boom, the boom cylinder body of the boom cylinder (2) being hinged to the excavator body, the boom piston rod of the boom cylinder (2) being hinged to the boom, the boom cylinder body of the boom cylinder (1) being hinged to the boom, the boom piston rod of the boom cylinder (1) being hinged to the boom, the bucket cylinder body of the bucket cylinder (3) being hinged to the boom, and the bucket piston rod of the bucket cylinder (3) being hinged to the bucket.

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