Movable arm decoupling hydraulic system and excavator

Abstract

The invention relates to the technical field of vehicles, and particularly discloses a movable arm decoupling hydraulic system and an excavator, the hydraulic system comprises an oil supplementing pump, a first movable arm oil pump, a second movable arm oil pump, a balance valve and a combination pump set, and the two ends of the oil supplementing pump are connected with an oil tank and an oil supplementing oil way respectively; two ends of the first movable arm oil pump are respectively connected with a movable arm rodless cavity and a movable arm rod cavity; the two ends of the second movable arm oil pump are connected with the oil supplementing oil way and the movable arm rodless cavity correspondingly, and the first movable arm oil pump and the second movable arm oil pump can rotate forwards and reversely. The balance valve is used for communicating the oil supplementing oil way with one of the movable arm rod cavity and the movable arm rodless cavity with smaller oil pressure; the combination pump set is used for supplying oil to the bucket rod oil cylinder and the bucket oil cylinder, by arranging the balance valve, replacement of hot oil in the hydraulic loop and normal-temperature oil in recharging and returning oil can be achieved, it is guaranteed that the oil temperature in the hydraulic loop is normal, then normal work of the movable arm oil cylinder is guaranteed, temperature monitoring does not need to be arranged, and cost can be effectively reduced.

Description

Technical Field

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

[0002] Traditional excavators use engines to drive hydraulic pumps, and the output flow of hydraulic pumps is usually controlled by centralized valve-controlled throttling speed regulation and distributed to actuators such as the dipper cylinder, boom cylinder, and bucket cylinder. However, this centralized valve-controlled throttling speed regulation has large energy losses and low control freedom; multiple actuators cannot be decoupled, and load differences cause serious energy waste. The flow distribution of multiple actuators is complex, with low flexibility and poor overall machine controllability.

[0003] In this regard, in the prior art, such as the previous patent with application number CN202410833273.8, a networked electro-hydraulic drive system is disclosed, which supplies oil to all actuators through independent oil sources to achieve complete decoupling of each circuit, eliminating the energy waste caused by load coupling when multiple actuators of the excavator perform compound actions. However, the open pumps used in each circuit control the movement speed and direction of the cylinder through a multi-way reversing valve, which will cause a large impact on the system action. The negative load energy is completely lost by the multi-way valve intercepting the flow and heating, and energy recovery cannot be achieved, resulting in low operating efficiency of the hydraulic system. In addition, each pump is responsible for supplying oil to multiple cylinders, and the decoupling effect is poor.

[0004] The prior art also provides a closed hydraulic system, which connects the rod chamber and the rodless chamber of the oil cylinder through an oil pump to realize the flow of oil in the two chambers. At the same time, an accumulator is also configured to compensate for the flow difference between the rod chamber and the rodless chamber and recover part of the energy, thereby realizing the decoupling of the oil cylinder. However, in this system, the accumulator will overflow at high pressure when the maximum pressure is reached, and the pipeline connected to the rod chamber and the rodless chamber will also overflow at high pressure when the maximum pressure is reached. This will cause power loss and generate a lot of heat to 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 a low-pressure overflow valve, and the oil in the oil tank needs to be replenished into the system, affecting the normal operation of the oil cylinder. Summary of the invention

[0005] The purpose of the present invention is to provide a boom decoupling hydraulic system and an excavator, so as to optimize the thermal balance of the existing boom decoupling hydraulic system.

[0006] In one aspect, the present invention provides a boom decoupling hydraulic system, the boom decoupling hydraulic system comprising:

[0007] It includes a boom cylinder, a bucket cylinder and a dipper rod cylinder, wherein the boom cylinder includes a boom rod chamber and a boom rodless chamber with variable volume, and is characterized in that the boom decoupling hydraulic system also includes:

[0008] 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;

[0009] A first boom oil pump, one end of which is connected to the boom rodless cavity, and the other end of which is connected to the boom rod cavity, and the first boom oil pump can rotate forward and reverse;

[0010] A second boom oil pump, one end of which is connected to the oil replenishment circuit, and the other end of which is connected to the boom rodless chamber, and the second boom oil pump can rotate forward and reverse;

[0011] a balancing valve, the balancing valve connecting the one with a smaller oil pressure between the boom rod chamber and the boom rodless chamber to the oil replenishment passage;

[0012] The compound pump group is used for supplying oil to the boom cylinder and the bucket cylinder.

[0013] As a preferred technical solution of the boom decoupling hydraulic system, one end of the first boom oil pump is connected to the boom rodless chamber through a first oil circuit, the other end of the first boom oil pump is connected to the boom rod chamber through a second oil circuit, and the second boom oil pump is connected to the first oil circuit through a third oil circuit;

[0014] The boom decoupling hydraulic system also includes a first control valve arranged in the first oil circuit, the first control valve is located between the connection between the third oil circuit and the first oil circuit and the boom rodless chamber, and the first control valve is used to control the connection and disconnection of the first oil circuit.

[0015] As a preferred technical solution for the boom decoupling hydraulic system, the boom decoupling hydraulic system also includes a second control valve, which is located between the connection between the third oil circuit and the first oil circuit and the first boom oil pump, and the second control valve is used to control the connection or disconnection of the first oil circuit.

[0016] As an optimal technical solution for the boom decoupling hydraulic system, the bucket cylinder includes a bucket rod chamber and a bucket rodless chamber with variable volume, the arm cylinder includes an arm rod chamber and an arm rodless chamber with variable volume, the compound pump group includes a first compound oil pump and a second compound oil pump, the input end of the first compound oil pump is connected to the oil replenishment circuit, the first compound oil pump can supply oil to either the bucket rodless chamber or the bucket rod chamber, and the first compound oil pump can also supply oil to either the arm rodless chamber or the arm rod chamber together with the second compound oil pump.

[0017] As a preferred technical solution of the boom decoupling hydraulic system, the boom decoupling hydraulic system also includes a drive system, and the drive system includes:

[0018] A first motor, the first motor can rotate forward and reverse, the first motor is respectively connected to the first boom oil pump and the second boom oil pump, and the first motor can drive the first boom oil pump and the second boom oil pump to rotate at the same time;

[0019] a second motor, the second motor being transmission-connected to the first compound oil pump and used for driving the first compound oil pump to rotate;

[0020] a third motor, the third motor being transmission-connected to the second compound oil pump and used for driving the second compound oil pump to rotate;

[0021] An oil replenishing motor, the oil replenishing motor is drivingly connected to the oil replenishing pump, and the oil replenishing motor is used to drive the oil replenishing pump to rotate;

[0022] A battery is electrically connected to the first motor, the second motor, the third motor and the fuel replenishment motor respectively.

[0023] As a preferred technical solution of the boom decoupling hydraulic system, the boom decoupling hydraulic system also includes a drive system, and the drive system includes:

[0024] A first motor, the first motor can rotate forward and reverse, the first motor is connected to the first boom oil pump and the second boom oil pump at the same time, and the first motor can drive the first boom oil pump and the second boom oil pump to rotate at the same time;

[0025] a second motor, the second motor being transmission-connected to the first compound oil pump and used for driving the first compound oil pump to rotate;

[0026] a third motor, the third motor being drivingly connected to the second compound oil pump and used for driving the second compound oil pump to rotate;

[0027] An oil replenishing motor, the oil replenishing motor is drivingly connected to the oil replenishing pump, and the oil replenishing motor is used to drive the oil replenishing pump to rotate;

[0028] a battery, wherein the battery is electrically connected to the first motor, the second motor, the third motor and the fuel replenishing motor respectively;

[0029] A first internal combustion engine and a first generator, wherein the first internal combustion engine is transmission-connected to the first generator and is used to drive the first generator to rotate, and the first generator is electrically connected to the battery.

[0030] As a preferred technical solution of the boom decoupling hydraulic system, the boom decoupling hydraulic system also includes a drive system, and the drive system includes:

[0031] A first motor, the first motor can rotate forward and reverse, the first motor is connected to the first boom oil pump and the second boom oil pump at the same time, and the first motor can drive the first boom oil pump and the second boom oil pump to rotate at the same time;

[0032] a second internal combustion engine, the second internal combustion engine being transmission-connected to the first compound oil pump and the second compound oil pump, respectively, and the second internal combustion engine being used to drive the first compound oil pump and the second compound oil pump to rotate simultaneously;

[0033] a second generator, wherein the second internal combustion engine is drivingly connected to the second generator, and the second internal combustion engine is used to drive the second generator to rotate;

[0034] An oil replenishing motor, the oil replenishing motor is drivingly connected to the oil replenishing pump, and the oil replenishing motor is used to drive the oil replenishing pump to rotate;

[0035] A battery is electrically connected to the first motor, the fuel replenishment motor and the second generator respectively.

[0036] As a preferred technical solution of the boom decoupling hydraulic system, the boom decoupling hydraulic system further includes:

[0037] a first valve, wherein the first valve is capable of connecting the output end of the first compound oil pump to one of the boom rod chamber and the boom rodless chamber, and connecting the oil tank to the other of the boom rod chamber and the boom rodless chamber;

[0038] a second valve capable of connecting an output end of the first compound oil pump to one of the bucket rod chamber and the bucket rodless chamber, and connecting an oil tank to the other of the bucket rod chamber and the bucket rodless chamber;

[0039] The third valve can connect the output end of the second compound oil pump with one of the boom rod chamber and the boom rodless chamber, and connect the oil tank with the other of the boom rod chamber and the boom rodless chamber.

[0040] As an optimal technical solution for the boom decoupling hydraulic system, the boom decoupling hydraulic system also includes a first oil supply check valve and a second oil supply check valve, the first oil supply check valve being connected between the oil supply oil circuit and the boom rodless chamber, and the first oil supply check valve only allows oil to flow from the oil supply oil circuit to the boom rodless chamber; the second oil supply check valve is connected between the oil supply oil circuit and the boom rod chamber, and the second oil supply check valve only allows oil to flow from the oil supply oil circuit to the boom rod chamber.

[0041] As a preferred 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 being connected between the oil replenishment circuit and the boom rodless chamber, and the first overflow valve only allows oil to overflow from the boom rodless chamber to the oil replenishment circuit; the second overflow valve is connected between the oil replenishment circuit and the boom rod chamber, and the second overflow valve only allows oil to overflow from the boom rod chamber to the oil replenishment circuit.

[0042] The boom decoupling hydraulic system provided by the present invention has at least the following beneficial effects:

[0043] The boom decoupling hydraulic system includes an oil replenishment pump, a first boom oil pump, a second boom oil pump, a balancing valve and a compound pump group, one end of the oil replenishment pump is connected to the oil tank, and the other end is connected to the oil replenishment circuit; one end of the first boom oil pump is connected to the boom rodless chamber, and the other end is connected to the boom rod chamber, and the first boom oil pump can rotate forward and reverse; one end of the second boom oil pump is connected to the oil replenishment circuit, and the other end is connected to the boom rodless chamber, and the second boom oil pump can rotate forward and reverse; the balancing valve connects the boom rod chamber and the boom rodless chamber with the smaller oil pressure to the oil replenishment circuit; the compound pump group is used to supply oil to the boom cylinder and the bucket cylinder. When the temperature of the oil in the hydraulic circuit is too high, the balancing valve can be used to replace the hot oil in the hydraulic circuit with the oil in the oil replenishing circuit. Since the temperature of the oil in the oil replenishing circuit is relatively low, the oil temperature in the hydraulic circuit can be reduced and kept at a normal temperature, thereby ensuring the normal operation of the boom cylinder. Compared with the existing technology, there is no need to configure temperature monitoring, and the cost can be effectively reduced.

[0044] On the other hand, the present invention provides an excavator, which includes the boom decoupling hydraulic system described in any of the above-mentioned schemes, and the excavator also includes an excavator body, a boom articulated with the excavator body, and 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, 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.

[0045] The excavator provided by the present invention has at least the following beneficial effects:

[0046] The excavator includes the above-mentioned boom decoupling hydraulic system, which can realize boom decoupling and optimize the thermal balance of the boom decoupling hydraulic system. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1It is a schematic diagram of a first partial structure of a boom decoupling hydraulic system in an embodiment of the present invention (the boom piston rod is in an extended position);

[0048] Figure 2 It is a schematic diagram of a second partial structure of the boom decoupling hydraulic system in an embodiment of the present invention (the boom piston rod is in the retracted position);

[0049] Figure 3 It is a schematic diagram of the third partial structure of the boom decoupling hydraulic system in an embodiment of the present invention (the bucket piston rod and the arm piston rod are extended at the same time);

[0050] Figure 4 It is a schematic diagram of the fourth partial structure of the boom decoupling hydraulic system in an embodiment of the present invention (the bucket piston rod and the arm piston rod are retracted at the same time);

[0051] Figure 5 It is a structural schematic diagram of a driving system in a boom decoupling hydraulic system in an embodiment of the present invention;

[0052] Figure 6 It is another structural schematic diagram of a driving system in a boom decoupling hydraulic system in an embodiment of the present invention;

[0053] Figure 7 It is another structural schematic diagram of the driving system in the boom decoupling hydraulic system in an embodiment of the present invention.

[0054] In the figure:

[0055] 1. Boom cylinder; 101. Boom rod chamber; 102. Boom rodless chamber;

[0056] 2. Bucket cylinder; 201. Bucket with rod chamber; 202. Bucket without rod chamber;

[0057] 3. Arm cylinder; 301, arm with rod cavity; 302, arm without rod cavity;

[0058] 4. First boom oil pump; 5. Second boom oil pump; 6. Make-up oil pump; 7. Balance valve;

[0059] 801, hydraulically controlled reversing valve; 802, first hydraulically controlled one-way valve; 803, first electromagnetic switch valve; 804, second electromagnetic switch valve;

[0060] 901, oil replenishment circuit; 902, first oil circuit; 903, second oil circuit; 904, third oil circuit; 905, arm large cavity oil circuit; 906, arm small cavity oil circuit; 907, bucket large cavity oil circuit; 908, bucket small cavity oil circuit; 909, first composite oil circuit; 910, second composite oil circuit;

[0061] 10. Second control valve; 11. First oil replenishment non-return valve; 12. Second oil replenishment non-return valve; 13. First overflow valve; 14. Second overflow valve; 15. First compound oil pump; 16. Second compound oil pump; 17. Oil replenishment overflow valve; 18. Oil tank; 19. First motor; 20. Second motor; 21. Third motor; 22. Oil replenishment motor; 23. Second generator; 24. Battery; 25. First generator; 26. First internal combustion engine; 27. Second internal combustion engine; 28. Rotary motor; 29. ​​Left travel motor; 30. Right travel motor; 31. Solenoid reversing valve; 32. First valve; 33. Second valve; 34. Third valve; 35. Second hydraulically controlled non-return valve; 36. Oil return line. DETAILED DESCRIPTION

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] The boom decoupling hydraulic system in the prior art supplies oil to all actuators through an independent oil source to achieve complete decoupling of each circuit, eliminating the energy waste caused by load coupling when multiple actuators of the excavator perform compound actions; in addition, the rod chamber and the rodless chamber of the oil cylinder can be connected by an oil pump to achieve the flow of oil in the two chambers, and an accumulator is configured to compensate for the flow difference between the rod chamber and the rodless chamber and recover part of the energy, thereby achieving complete decoupling of the oil cylinder. However, in this system, the accumulator will overflow at high pressure when the maximum pressure is reached, and the pipeline connected to the rod chamber and the rodless chamber will also overflow at high pressure when the maximum pressure is reached, which will cause power loss and generate a lot of heat to affect the thermal balance of the system. In order to avoid excessive oil temperature in the system, additional temperature monitoring is required. 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 is replenished into the system, affecting the normal operation of the oil cylinder.

[0067] In this regard, the present embodiment provides a boom decoupling hydraulic system to solve the above-mentioned problem. The boom decoupling hydraulic system can be integrated into an excavator.

[0068] Please refer to Figures 1 to 4 The boom decoupling hydraulic system includes a boom cylinder 1, a bucket cylinder 2 and an arm cylinder 3.

[0069] Please refer to Figure 1 and Figure 2 The boom cylinder 1 includes a boom rod chamber 101 and a boom rodless chamber 102 with variable volumes. The boom cylinder 1 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 the boom rod chamber 101 and the boom rodless chamber 102. The boom piston rod passes through the boom rod chamber 101 so that the cross-sectional area of ​​the boom rod chamber 101 is smaller than the cross-sectional area of ​​the boom rodless chamber 102. 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 101 and the boom rodless chamber 102 increase and decrease. In this embodiment, the boom cylinder body is hinged to the body of the excavator, the boom piston rod is hinged to the boom, and the number of the boom cylinders 1 is specifically two.

[0070] Please refer to Figure 3 and Figure 4The arm oil cylinder 3 includes an arm rod chamber 301 and an arm rodless chamber 302 with variable volumes. The arm oil cylinder 3 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 301 and the arm rodless chamber 302. The arm piston rod passes through the arm rod chamber 301 so that the cross-sectional area of ​​the arm rod chamber 301 is smaller than the cross-sectional area of ​​the arm rodless chamber 302. 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 301 and the arm rodless chamber 302 increase and decrease. In this embodiment, the arm cylinder body is hinged to the boom, the arm piston rod is hinged to the arm, and the number of the arm oil cylinder 3 is specifically one.

[0071] Please refer to Figure 3 and Figure 4 The bucket cylinder 2 includes a bucket rod chamber 201 and a bucket rodless chamber 202 with variable volumes. The bucket cylinder 2 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 201 and the bucket rodless chamber 202. The bucket piston rod passes through the bucket rod chamber 201 so that the cross-sectional area of ​​the bucket rod chamber 201 is smaller than the cross-sectional area of ​​the bucket rodless chamber 202. 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 201 and the bucket rodless chamber 202 increase and decrease. In this embodiment, the bucket cylinder body is hinged to the bucket rod, the bucket piston rod is hinged to the bucket, and the number of bucket cylinders 2 is specifically one.

[0072] Please refer to Figure 1 and Figure 2 The boom decoupling hydraulic system further includes an oil replenishment pump 6. One end of the oil replenishment pump 6 is connected to the oil tank 18, and the other end is connected to the oil replenishment oil circuit 901. The oil replenishment pump 6 can pump the oil in the oil tank 18 to the oil replenishment oil circuit 901, and supply oil to other oil circuits through the oil replenishment oil circuit 901.

[0073] Optionally, the boom decoupling hydraulic system further includes an oil replenishment overflow valve 17 connected to the oil replenishment oil circuit 901 , and the oil replenishment overflow valve 17 is used to overflow the oil in the oil replenishment oil circuit 901 that exceeds a set pressure to the oil tank 18 .

[0074] In this embodiment, the boom decoupling hydraulic system further includes a first boom oil pump 4 and a second boom oil pump 5. Among them, one end of the first boom oil pump 4 is connected to the boom rodless chamber 102, and the other end of the first boom oil pump 4 is connected to the boom rod chamber 101, and the first boom oil pump 4 can rotate forward and reverse; one end of the second boom oil pump 5 is connected to the oil replenishment oil circuit 901, and the other end of the second boom oil pump 5 is connected to the boom rodless chamber 102, and the second boom oil pump 5 can rotate forward and reverse. In the present embodiment, the first boom oil pump 4 and the second boom oil pump 5 both adopt closed oil pumps, specifically closed metering pumps. The first boom oil pump 4 and the two oil chambers of the boom cylinder 1 constitute a hydraulic circuit, and the second boom oil pump 5, the boom rodless chamber 102 and the oil replenishing circuit 901 constitute a hydraulic circuit, which can effectively reduce energy loss compared with an open pump; and the boom cylinder 1 is supplied with oil through the first boom oil pump 4 and the second boom oil pump 5, thereby realizing decoupling of the boom cylinder 1, thereby improving the control performance of the boom cylinder 1.

[0075] 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 boom oil pump 4 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, it is also necessary to use the second boom oil pump 5 to simultaneously pump the oil in the oil replenishment circuit 901 into the boom rodless chamber 102 to compensate for the flow difference. At this time, the second boom oil pump 5 also rotates forward. When the boom piston rod moves to the retracted position, the boom piston rod gradually retracts inward, the first boom oil pump 4 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 boom oil pump 5 rotates in the opposite direction, and the second boom oil pump 5 pumps another part of the oil in the boom rodless chamber 102 to the oil replenishing circuit 901.

[0076] Please refer again Figure 1 and Figure 2The boom decoupling hydraulic system also includes a balancing valve 7. The balancing valve 7 connects the boom rod chamber 101 and the boom rodless chamber 102, whichever has a lower oil pressure, to the oil replenishing circuit 901. By setting the balancing valve 7, the oil in the boom rodless chamber 102 and the boom rod chamber 101, whichever has a lower oil pressure, can directly enter the oil replenishing circuit 901, or the oil in the oil replenishing circuit 901 can directly enter the boom rodless chamber 102 and the boom rod chamber 101, whichever has a lower oil pressure. Since the temperature of the oil in the oil replenishing circuit 901 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 that the oil temperature in the hydraulic circuit is normal, thereby ensuring the normal operation of the boom cylinder 1. Compared with the prior art, there is no need to configure temperature monitoring, and the cost can be effectively reduced.

[0077] In addition, connecting the boom rod chamber 101 and the boom rodless chamber 102 with the lower oil pressure to the oil replenishment circuit 901 through the balancing valve 7 can also effectively compensate for the flow difference between the boom rod chamber 101 and the boom rodless chamber 102.

[0078] In this embodiment, one end of the first boom oil pump 4 is connected to the boom rodless chamber 102 through the first oil circuit 902, the other end of the first boom oil pump 4 is connected to the boom rod chamber 101 through the second oil circuit 903, and the second boom oil pump 5 is connected to the first oil circuit 902 through the third oil circuit 904. When the oil pressure in the boom rodless chamber 102 is greater than the oil pressure in the boom rod chamber 101, the balancing valve 7 connects the second oil circuit 903 and the oil replenishing circuit 901. When the oil pressure in the boom rodless chamber 102 is less than the oil pressure in the boom rod chamber 101, the balancing valve 7 connects the first oil circuit 902 and the oil replenishing circuit 901.

[0079] 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. Taking the movement of the boom piston rod to the retracted position as an example, when 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 balance valve 7 connects the oil replenishment circuit 901 and the second oil circuit 903; when 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 balance valve 7 connects the oil replenishment circuit 901 and the first oil circuit 902. At this time, the balance valve 7 can also balance the flow difference between the rod chamber and the rod chamber.

[0080] In this embodiment, the balancing valve 7 includes a P1 interface, an A 11 Interface and A 12Interface, where P1 interface is connected to the oil replenishment circuit 901, A 11 The interface is connected to the first oil circuit 902, A 12 The balancing valve 7 has a first left position and a first right position. When the balancing valve 7 is in the first left position, the balancing valve 7 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 replenishment circuit 901 is connected to the second oil circuit 903, and the oil replenishment circuit 901 is disconnected from the first oil circuit 902; when the balance valve 7 is in the first right position, the balance valve 7 makes the P1 interface and A 11 The interface is connected and A 12 The interface is disconnected, so that the oil replenishment circuit 901 is connected to the first oil circuit 902, and the oil replenishment circuit 901 is disconnected from the second oil circuit 903. Preferably, the balancing valve 7 also has a first middle position. When the balancing valve 7 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 901 to be disconnected from the first oil circuit 902 and the second oil circuit 903 at the same time.

[0081] In this embodiment, the balancing valve 7 is specifically a hydraulically controlled valve, and the balancing valve 7 has a first hydraulic control end and a second hydraulic control end, the first hydraulic control end is connected to the first oil circuit 902, and the second hydraulic control end is connected to the second oil circuit 903, the first hydraulic control end and the second hydraulic control end are respectively located on both sides of the valve core of the balancing valve 7, and the oil of the first hydraulic control end and the second hydraulic control end directly acts on the valve core of the balancing valve 7, and the force of the oil of the first hydraulic control end acting on the valve core of the balancing valve 7 is compared with the force of the oil of the second hydraulic control end acting on the valve core of the balancing valve 7 to determine the stop position of the valve core of the balancing valve 7. Specifically, when the oil pressure of the first hydraulic control end is greater than the oil pressure of the second hydraulic control end, the balancing valve 7 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 balancing valve 7 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 balancing valve 7 is located in the first middle position. In other embodiments, the balancing valve 7 can also be an electrically controlled valve.

[0082] Optionally, the boom decoupling hydraulic system further includes a first control valve disposed in the first oil circuit 902, the first control valve being located between the connection between the third oil circuit 904 and the first oil circuit 902 and the boom rodless chamber 102, and the first control valve being used to control the connection and disconnection of the first oil circuit 902. When the first control valve controls the first oil circuit 902 to be disconnected, the oil pressure in the boom rodless chamber 102 can be kept stable, thereby ensuring that the position of the boom piston rod can be kept stable.

[0083] Specifically, in this embodiment, the first control valve includes a hydraulically controlled reversing valve 801 and a first hydraulically controlled one-way valve 802 . Among them, the first hydraulically controlled one-way valve 802 includes a one-way valve housing and a one-way valve spool, the one-way valve housing has a first working interface and a second working interface, the first working interface and the second working interface are connected in series to the first oil circuit 902, and the first working interface is closer to the boom rodless chamber 102 relative to the second working interface; the one-way valve spool slides in the one-way valve housing, the one-way valve spool divides the inner chamber of the one-way valve housing into a spring chamber and a working chamber, the one-way valve spool can slide relative to the one-way valve housing and has an open position and a closed position, when the one-way valve spool is in the closed position, the one-way valve spool can further divide the working chamber into a first chamber and a second chamber that are not connected to each other, wherein the first working interface is always connected to the first chamber, and the second working interface is always connected to the second chamber, since the first chamber and the second chamber are separated, the first oil circuit 902 is disconnected; when the one-way valve spool is in the open position, the first chamber and the second chamber are connected, and at this time the first oil circuit 902 is connected.

[0084] The first hydraulically controlled one-way valve 802 also includes a one-way valve spring, and the one-way valve housing has a first control interface and a second control interface. The one-way valve spring is located in the spring cavity, and the two ends of the one-way valve spring are respectively abutted against the one-way valve core and the one-way valve housing, the first control interface is always connected to the first cavity, and the second control interface is always connected to the spring cavity. The one-way valve spring and the hydraulic oil in the spring cavity give the one-way valve core a force F1 to move to the closed position, and the hydraulic oil in the working cavity gives the one-way valve core a force F2 to move to the open position. The position of the one-way valve core is determined by comparing the sizes of F1 and F2.

[0085] Furthermore, the hydraulically controlled reversing valve 801 is a two-position three-way valve, and the hydraulically controlled reversing valve 801 can make the first control interface and the second control interface communicate with each other. At this time, the oil pressure in the working chamber and the spring chamber is equal, but the oil in the working chamber and the action area of ​​the one-way valve core are smaller than the action area of ​​the oil in the spring chamber and the one-way valve core, and the one-way valve spring in the spring chamber also gives the one-way valve core an action force, which can make the one-way valve core move to the closed position, ensuring that the first oil circuit 902 is closed stably. The hydraulically controlled reversing valve 801 can also make the second control interface and the oil tank 18 communicate with each other. At this time, the position of the one-way valve core is determined by comparing the sizes of F1 and F2. When F2>F1, the one-way valve spring is compressed, which can make the one-way valve core move to the open position, thereby opening the first oil circuit 902.

[0086] Among them, the working position of the hydraulically controlled reversing valve 801 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 18 can be connected and the first control interface is disconnected. In other embodiments, the hydraulically controlled reversing valve 801 can also be replaced by an electrically controlled reversing valve. Specifically, in this embodiment, the first control valve also includes a first electromagnetic switch valve 803 for controlling the on-off of the oil circuit of the hydraulic control end of the hydraulically controlled reversing valve 801. Therefore, the on-off of the signal oil source of the hydraulically controlled reversing valve 801 can be controlled by the first electromagnetic switch valve 803 to realize the switching control of the working position of the hydraulically controlled reversing valve 801.

[0087] Optionally, the boom decoupling hydraulic system further includes a second control valve 10, which is disposed in the first oil circuit 902, and is located between the connection between the third oil circuit 904 and the first oil circuit 902 and the first boom oil pump 4, and the second control valve 10 is used to control the connection or disconnection of the first oil circuit 902. When the second control valve 10 disconnects the first oil circuit 902, it can block the first boom oil pump 4 from supplying oil to the boom rodless chamber 102, and can prevent the oil in the boom rodless chamber 102 from flowing to the first boom oil pump 4, and at this time, the boom cylinder 1 is driven only by the second boom oil pump 5.

[0088] Specifically, in this embodiment, the second control valve 10 is also a hydraulically controlled valve, and the valve core of the second control valve 10 can move in the valve housing of the second control valve 10 and has a second left position, a second middle position, and a second right position. When the second control valve 10 is in the second left position and the second right position, the second control valve 10 connects the first oil circuit 902, and when the second control valve 10 is in the second middle position, the second control valve 10 disconnects the first oil circuit 902. The second control valve 10 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 902 near the first boom oil pump 4, and the P2 interface is connected to the side of the first oil circuit 902 near the boom oil cylinder 1. When the second control valve 10 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 902 is connected; when the second control valve 10 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 902 is also connected; when the second control valve 10 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 902 is disconnected.

[0089] The second control valve 10 includes a third hydraulic control end and a fourth hydraulic control end. The first solenoid switch valve 803 is also used to control the on-off of the oil circuit of the third hydraulic control end. The boom decoupling hydraulic system also includes a second solenoid switch valve 804. The second solenoid switch valve 804 is also used to control the on-off 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 second control valve 10, and the oil of the third hydraulic control end and the fourth hydraulic control end directly acts on the valve core of the second control valve 10. The force of the oil of the third hydraulic control end acting on the valve core of the second control valve 10 and the force of the oil of the fourth hydraulic control end acting on the valve core of the second control valve 10 are compared to determine the stop position of the valve core of the second control valve 10.

[0090] Optionally, the boom decoupling hydraulic system also includes a first oil replenishment check valve 11 and a second oil replenishment check valve 12, the first oil replenishment check valve 11 is connected between the oil replenishment oil circuit 901 and the boom rodless chamber 102, and the first oil replenishment check valve 11 only allows oil to flow from the oil replenishment oil circuit 901 to the boom rodless chamber 102, specifically, the first oil replenishment check valve 11 is connected between the oil replenishment oil circuit 901 and the first oil circuit 902; the second oil replenishment check valve 12 is connected between the oil replenishment oil circuit 901 and the boom rod chamber 101, and the second oil replenishment check valve 12 only allows oil to flow from the oil replenishment oil circuit 901 to the boom rod chamber 101, specifically, the second oil replenishment check valve 12 is connected between the oil replenishment oil circuit 901 and the second oil circuit 903. By providing the first oil replenishment check valve 11, when the oil pressure in the boom rodless chamber 102 is low, the boom rodless chamber 102 can be replenished with oil through the oil replenishment oil circuit 901. By providing the second oil replenishment check valve 12, when the oil pressure in the boom rod chamber 101 is low, the boom rod chamber 101 can be replenished with oil through the oil replenishment oil circuit 901, so as to further balance the flow difference between the boom rod chamber 101 and the boom rodless chamber 102. Specifically, the connection between the first oil replenishment check valve 11 and the first oil circuit 902 is located between the first hydraulically controlled check valve 802 and the boom cylinder 1.

[0091] Optionally, the boom decoupling hydraulic system further includes a first relief valve 13 and a second relief valve 14, wherein the first relief valve 13 is connected between the oil replenishment circuit 901 and the boom rodless chamber 102, and the first relief valve 13 only allows oil to overflow from the boom rodless chamber 102 to the oil replenishment circuit 901, specifically, the first relief valve 13 is connected between the oil replenishment circuit 901 and the first oil circuit 902; the second relief valve 14 is connected between the oil replenishment circuit 901 and the boom rod chamber 101, and the second relief valve 14 only allows oil to overflow from the boom rod chamber 101 to the oil replenishment circuit 901, specifically, the second relief valve 14 is connected between the oil replenishment circuit 901 and the boom rod chamber 101, and the second relief valve 14 only allows oil to overflow from the boom rod chamber 101 to the oil replenishment circuit 901, specifically, the second relief valve 14 is connected between the oil replenishment circuit 901 and the second oil circuit 903. By providing the first relief valve 13 and the second relief valve 14, the oil pressure in the boom rod chamber 101 and the boom rodless chamber 102 can be effectively balanced.

[0092] Please refer to Figure 3 and Figure 4 The boom decoupling hydraulic system also includes a compound pump group, which is used to supply oil to the arm cylinder 3 and the bucket cylinder 2. In this embodiment, the bucket cylinder 2 and the arm cylinder 3 are compounded, and the boom cylinder 1 is decoupled. Compared with the overall compound of the bucket cylinder 2, the arm cylinder 3 and the boom cylinder 1, the flexibility of the control of the boom cylinder 1 can be improved, and the controllability of the whole machine can be improved.

[0093] Optionally, in this embodiment, the compound pump group includes a first compound oil pump 15 and a second compound oil pump 16. The input end of the first compound oil pump 15 is connected to the oil replenishment oil circuit 901, and the first compound oil pump 15 can supply oil to either the bucket rodless chamber 202 or the bucket rod chamber 201; the first compound oil pump 15 can also supply oil to either the dipper rodless chamber 302 or the dipper rod chamber 301 together with the second compound oil pump 16. Preferably, the first compound oil pump 15 and the second compound oil pump 16 are both open pumps.

[0094] Optionally, in this embodiment, the boom decoupling hydraulic system further includes a first valve 32, a second valve 33 and a third valve 34. The first valve 32 enables the output end of the first compound oil pump 15 to communicate with one of the dipper rod chamber 301 and the dipper rodless chamber 302, and enables the oil tank 18 to communicate with the other of the dipper rod chamber 301 and the dipper rodless chamber 302; the second valve 33 enables the output end of the first compound oil pump 15 to communicate with one of the bucket rod chamber 201 and the bucket rodless chamber 202, and enables the oil tank 18 to communicate with the other of the bucket rod chamber 201 and the bucket rodless chamber 202; the third valve 34 enables the output end of the second compound oil pump 16 to communicate with one of the dipper rod chamber 301 and the dipper rodless chamber 302, and enables the oil tank 18 to communicate with the other of the dipper rod chamber 301 and the dipper rodless chamber 302. With this arrangement, the first compound oil pump 15 can supply oil to the bucket cylinder 2 and the arm cylinder 3 respectively under the control of the first valve 32 and the second valve 33 , and the second compound oil pump 16 only supplies oil to the arm cylinder 3 under the control of the third valve 34 .

[0095] Specifically, in this embodiment, the boom decoupling hydraulic system also includes a large arm chamber oil circuit 905 connected to the arm rodless chamber 302, a small arm chamber oil circuit 906 connected to the arm rod chamber 301, a large bucket chamber oil circuit 907 connected to the bucket rodless chamber 202, a small bucket chamber oil circuit 908 connected to the bucket rod chamber 201, a first compound oil circuit 909, a second compound oil circuit 910 and an oil return circuit 36 ​​connected to the oil tank 18. Among them, the first compound oil circuit 909 is connected to the output end of the first compound oil pump 15; the second compound oil circuit 910 is connected to the output end of the second compound oil pump 16, the first valve 32 is simultaneously connected to the return oil circuit 36, the first compound oil circuit 909, the boom large cavity oil circuit 905 and the boom small cavity oil circuit 906; the second valve 33 is simultaneously connected to the return oil circuit 36, the first compound oil circuit 909, the bucket large cavity oil circuit 907 and the bucket small cavity oil circuit 908; the third valve 34 is simultaneously connected to the return oil circuit 36, the second compound oil circuit 910, the boom large cavity oil circuit 905 and the boom small cavity oil circuit 906.

[0096] The first valve 32 can connect the first composite oil circuit 909 with one of the large-chamber oil circuit 905 and the small-chamber oil circuit 906 of the bucket arm, and connect the return oil circuit 36 ​​with the other of the large-chamber oil circuit 905 and the small-chamber oil circuit 906 of the bucket arm. Specifically, the first valve 32 includes at least a P3 interface, an A 31 Interface, A 32 Interface and T1 interface, P3 interface connects to the first composite oil circuit 909, A 31 Interface connected to the large chamber oil circuit of the bucket rod 905, A 32 The interface is connected to the small chamber oil circuit 906 of the bucket rod, the T1 interface is connected to the return oil circuit 36, and the first valve 32 has a third left position and a third right position, such as Figure 3 As shown, when the first valve 32 is in the third right position, the P3 interface is connected to the A 31 Interface connectivity, A 32 The interface is connected to the T1 interface, so that the first composite oil circuit 909 is connected to the large chamber oil circuit 905 of the bucket arm, and the return oil circuit 36 ​​is connected to the small chamber oil circuit 906 of the bucket arm. A part of the oil pumped by the first composite oil pump 15 can be pumped to the bucket arm non-rod chamber 302 through the first valve 32, and the oil in the bucket arm rod chamber 301 is delivered to the oil tank 18 through the first valve 32. Figure 4 As shown, when the first valve 32 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 first compound oil circuit 909 is connected with the small chamber oil circuit 906 of the boom, and the return oil circuit 36 ​​is connected with the large chamber oil circuit 905 of the boom. A part of the oil pumped by the first compound oil pump 15 can be pumped to the boom rod chamber 301 through the first valve 32, and the oil in the boom rodless chamber 302 is transported to the oil tank 18 through the first valve 32.

[0097] The second valve 33 can connect the first composite oil circuit 909 with one of the bucket large cavity oil circuit 907 and the bucket small cavity oil circuit 908, and connect the return oil circuit 36 ​​with the other of the bucket large cavity oil circuit 907 and the bucket small cavity oil circuit 908. Specifically, the second valve 33 includes at least a P4 interface, an A 41 Interface, A 42 Interface and T2 interface, P4 interface connects to the first composite oil circuit 909, A 41 Interface connection bucket large cavity oil circuit 907, A 42 The interface is connected to the bucket small chamber oil circuit 908, the T2 interface is connected to the return oil circuit 36, and the second valve 33 has a fourth left position and a fourth right position, such as Figure 3 As shown, when the second valve 33 is in the fourth right 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 first composite oil circuit 909 is connected to the bucket large chamber oil circuit 907, and the return oil circuit 36 ​​is connected to the bucket small chamber oil circuit 908. Another part of the oil pumped by the first composite oil pump 15 can be pumped to the bucket rodless chamber 202 through the second valve 33, and the oil in the bucket rod chamber 201 is delivered to the oil tank 18 through the second valve 33. When the second valve 33 is in the fourth left position, the P4 interface is connected to the A 42 Interface connectivity, A 41 The interface is connected with the T2 interface, so that the first compound oil circuit 909 is connected with the bucket small chamber oil circuit 908, and the return oil circuit 36 ​​is connected with the bucket large chamber oil circuit 907. Another part of the oil pumped by the first compound oil pump 15 can be pumped to the bucket rod chamber 201 through the second valve 33, and the oil in the bucket rodless chamber 202 is transported to the oil tank 18 through the second valve 33.

[0098] The third valve 34 can connect the second compound oil pump 16 with one of the large-chamber oil circuit 905 and the small-chamber oil circuit 906 of the bucket arm, and connect the return oil circuit 36 ​​with the other of the large-chamber oil circuit 905 and the small-chamber oil circuit 906 of the bucket arm. Specifically, the third valve 34 includes at least a P5 interface, an A 51 Interface, A 52 Interface and T3 interface, P5 interface connects to the second composite oil circuit 910, A 51 Interface connected to the large chamber oil circuit of the bucket rod 905, A 52 The interface is connected to the small chamber oil circuit 906 of the bucket rod, the T3 interface is connected to the return oil circuit 36, and the third valve 34 has a fifth left position and a fifth right position, such as Figure 3 As shown, when the third valve 34 is in the fifth left position, the P5 interface is connected to the A 51 Interface connectivity, A 52The interface is connected with the T3 interface, so that the second compound oil pump 16 is connected with the large chamber oil circuit 905 of the bucket arm, and the return oil circuit 36 ​​is connected with the small chamber oil circuit 906 of the bucket arm. The oil pumped by the second compound oil pump 16 can be pumped to the bucket arm non-rod chamber 302 through the third valve 34, and the oil in the bucket arm rod chamber 301 can be delivered to the oil tank 18 through the third valve 34. Figure 4 As shown, when the third valve 34 is in the fifth right position, the P5 interface is connected to the A 52 Interface connectivity, A 51 The interface is connected to the T3 interface, so that the second compound oil pump 16 is connected to the small chamber oil circuit 906 of the boom, and the return oil circuit 36 ​​is connected to the large chamber oil circuit 905 of the boom. The oil pumped by the second compound oil pump 16 can enter the boom rod chamber 301 through the third valve 34, and the oil in the boom rodless chamber 302 can be transported to the oil tank 18 through the third valve 34.

[0099] In this embodiment, the first valve 32, the second valve 33 and the third valve 34 are all solenoid valves. In other embodiments, the first valve 32, the second valve 33 and the third valve 34 may also be hydraulically controlled valves as required.

[0100] Optionally, the boom decoupling hydraulic system further includes a fourth valve disposed in the boom small chamber oil circuit 906, and the fourth valve is used to control the connection and disconnection of the boom small chamber oil circuit 906. The fourth valve includes a second hydraulically controlled one-way valve 35 and an electromagnetic reversing valve 31, and the second hydraulically controlled one-way valve 35 has the same structure as the first hydraulically controlled one-way valve 802, and the electromagnetic reversing valve 31 is used to connect the first control interface and the second control interface in the second hydraulically controlled one-way valve 35, or connect the second control interface and the oil tank 18 and disconnect the first control interface, so as to control the position of the one-way valve core of the second hydraulically controlled one-way valve 35.

[0101] Optionally, see Figures 5 to 7 The boom decoupling hydraulic system also includes a drive system, which may be a pure electric drive system, a hybrid drive system or an extended-range drive system.

[0102] Please refer to Figure 5When the drive system is a pure electric drive system, the drive system includes a first motor 19, a second motor 20, a third motor 21, an oil replenishment motor 22 and a battery 24. Among them, the first motor 19 can rotate forward and reverse, and the first motor 19 is respectively connected to the first boom oil pump 4 and the second boom oil pump 5, and the first motor 19 can simultaneously drive the first boom oil pump 4 and the second boom oil pump 5 to rotate; the second motor 20 is connected to the first composite oil pump 15, and the second motor 20 is used to drive the first composite oil pump 15 to rotate; the third motor 21 is connected to the second composite oil pump 16, and the third motor 21 is used to drive the second composite oil pump 16 to rotate; the oil replenishment motor 22 is connected to the oil replenishment pump 6, and the oil replenishment motor 22 is used to drive the oil replenishment pump 6 to rotate; the battery 24 is respectively electrically connected to the first motor 19, the second motor 20, the third motor 21 and the oil replenishment motor 22. The use of a pure electric drive system can effectively reduce the complexity of system control, improve the controllability of the system, and improve the system efficiency.

[0103] In this embodiment, the speed of the first motor 19 is controlled to control the extension and retraction speed of the boom piston rod of the boom cylinder 1. In addition, when the boom piston rod is retracted, the boom is lowered by its own weight, and the first boom oil pump 4 and / or the second boom oil pump 5 drive the first motor 19 to reverse, which can generate electricity and store it in the battery 24, thereby realizing the recycling of system energy.

[0104] As an alternative, see Figure 6 When the drive system is an extended-range drive system, the drive system includes a first motor 19 , a second motor 20 , a third motor 21 , a refueling motor 22 , a battery 24 , a first internal combustion engine 26 and a first generator 25 . Among them, the first motor 19 can rotate forward and reverse, and the first motor 19 is connected to the first boom oil pump 4 and the second boom oil pump 5 at the same time, and the first motor 19 can drive the first boom oil pump 4 and the second boom oil pump 5 to rotate at the same time; the second motor 20 is connected to the first compound oil pump 15, and the second motor 20 is used to drive the first compound oil pump 15 to rotate; the third motor 21 is connected to the second compound oil pump 16, and the third motor 21 is used to drive the second compound oil pump 16 to rotate; the replenishment motor 22 is connected to the replenishment pump 6, and the replenishment motor 22 is used to drive the replenishment pump 6 to rotate; the battery 24 is electrically connected to the first motor 19, the second motor 20, the third motor 21 and the replenishment motor 22 respectively; the first internal combustion engine 26 is connected to the first generator 25 and is used to drive the first generator 25 to rotate, and the first generator 25 is electrically connected to the battery 24. The use of the extended-range drive system can avoid the problem of relying solely on the battery 24 for power supply, and the whole machine needs to be limited by the maximum storage capacity of the battery 24.

[0105] As an alternative, see Figure 7When the drive system is a hybrid drive system, the drive system includes a first motor 19, a second internal combustion engine 27, a second generator 23, an oil replenishment motor 22 and a battery 24. The first motor 19 can rotate forward and reverse, and the first motor 19 is simultaneously connected to the first boom oil pump 4 and the second boom oil pump 5, and the first motor 19 can simultaneously drive the first boom oil pump 4 and the second boom oil pump 5 to rotate; the second internal combustion engine 27 is respectively connected to the first compound oil pump 15, the second generator 23 and the second compound oil pump 16, and the second internal combustion engine 27 is used to drive the first compound oil pump 15, the second generator 23 and the second compound oil pump 16 to rotate simultaneously; the oil replenishment motor 22 is connected to the oil replenishment pump 6, and the oil replenishment motor 22 is used to drive the oil replenishment pump 6 to rotate; the battery 24 is respectively electrically connected to the first motor 19, the oil replenishment motor 22 and the second generator 23. Compared with a pure electric drive system, the hybrid drive system does not need to be limited by the maximum storage capacity of the battery 24; compared with an extended-range drive system, the number of motors can be effectively reduced.

[0106] Optionally, the drive system further includes a slewing motor 28, a left travel motor 29 and a right travel motor 30. The slewing motor 28 is used to drive the slewing mechanism of the excavator, and the left travel motor 29 and the right travel motor 30 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 24 also supplies power to the slewing motor 28, the left travel motor 29 and the right travel motor 30, respectively.

[0107] The present invention also provides an excavator, which includes the above-mentioned boom decoupling hydraulic system, the excavator also includes 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 1 is hinged to the excavator body, the boom piston rod of the boom cylinder 1 is hinged to the boom, the boom cylinder body of the boom cylinder 3 is hinged to the boom, the boom piston rod of the boom cylinder 3 is hinged to the boom, the bucket cylinder body of the bucket cylinder 2 is hinged to the boom, and the bucket piston rod of the bucket cylinder 2 is hinged to the bucket. The excavator can realize boom decoupling and optimize the thermal balance arm of the boom decoupling hydraulic system.

[0108] 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 bucket cylinder (2) and an arm cylinder (3), wherein the boom cylinder (1) comprises a boom rod chamber (101) and a boom rodless chamber (102) with variable volumes, characterized in that: The boom decoupling hydraulic system further comprises: An oil replenishment pump (6), one end of the oil replenishment pump (6) being connected to the oil tank (18) and the other end of the oil replenishment pump (6) being connected to the oil replenishment circuit (901); A first boom oil pump (4), one end of which is connected to the boom rodless chamber (102), and the other end of which is connected to the boom rod chamber (101), the first boom oil pump (4) being capable of forward and reverse rotation; A second boom oil pump (5), one end of which is connected to the oil replenishment circuit (901), and the other end of which is connected to the boom rodless chamber (102), the second boom oil pump (5) being capable of forward and reverse rotation; A balancing valve (7), the balancing valve (7) connecting one of the boom rod chamber (101) and the boom rodless chamber (102) with a smaller oil pressure to the oil replenishment passage (901); The compound pump group is used to supply oil to the boom cylinder (3) and the bucket cylinder (2).

2. The boom decoupling hydraulic system according to claim 1, characterized in that: One end of the first boom oil pump (4) is connected to the boom rodless chamber (102) via a first oil circuit (902), the other end of the first boom oil pump (4) is connected to the boom rod chamber (101) via a second oil circuit (903), and the second boom oil pump (5) is connected to the first oil circuit (902) via a third oil circuit (904); The boom decoupling hydraulic system also includes a first control valve arranged in the first oil circuit (902), the first control valve is located between the connection between the third oil circuit (904) and the first oil circuit (902) and the boom rodless chamber (102), and the first control valve is used to control the connection and disconnection of the first oil circuit (902).

3. The boom decoupling hydraulic system according to claim 2, characterized in that: The boom decoupling hydraulic system further comprises a second control valve (10), the second control valve (10) being located between the connection between the third oil circuit (904) and the first oil circuit (902) and the first boom oil pump (4), the second control valve (10) being used to control the connection or disconnection of the first oil circuit (902).

4. The boom decoupling hydraulic system according to claim 1, characterized in that: The bucket oil cylinder (2) comprises a bucket rod chamber (201) and a bucket rodless chamber (202) with variable volumes, the arm oil cylinder (3) comprises an arm rod chamber (301) and an arm rodless chamber (302) with variable volumes, and the compound pump group comprises a first compound oil pump (15) and a second compound oil pump (16); The input end of the first compound oil pump (15) is connected to the oil replenishment circuit (901), and the first compound oil pump (15) can supply oil to either the bucket rodless chamber (202) or the bucket rod chamber (201), and the first compound oil pump (15) can also supply oil to either the dipper arm rodless chamber (302) or the dipper arm rod chamber (301) together with the second compound oil pump (16).

5. The boom decoupling hydraulic system according to claim 4, characterized in that: The boom decoupling hydraulic system also includes a drive system, which includes: a first motor (19), the first motor (19) being capable of forward and reverse rotation, the first motor (19) being respectively connected in transmission with the first boom oil pump (4) and the second boom oil pump (5), and the first motor (19) being capable of simultaneously driving the first boom oil pump (4) and the second boom oil pump (5) to rotate; a second motor (20), the second motor (20) being transmission-connected to the first compound oil pump (15), and the second motor (20) being used to drive the first compound oil pump (15) to rotate; a third motor (21), the third motor (21) being drivingly connected to the second compound oil pump (16), and the third motor (21) being used to drive the second compound oil pump (16) to rotate; an oil replenishing motor (22), the oil replenishing motor (22) being in transmission connection with the oil replenishing pump (6), and the oil replenishing motor (22) being used to drive the oil replenishing pump (6) to rotate; A battery (24), the battery (24) being electrically connected to the first motor (19), the second motor (20), the third motor (21) and the fuel replenishment motor (22) respectively.

6. The boom decoupling hydraulic system according to claim 4, characterized in that: The boom decoupling hydraulic system also includes a drive system, which includes: a first motor (19), the first motor (19) being capable of forward and reverse rotation, the first motor (19) being simultaneously transmission-connected to the first boom oil pump (4) and the second boom oil pump (5), and the first motor (19) being capable of simultaneously driving the first boom oil pump (4) and the second boom oil pump (5) to rotate; a second motor (20), the second motor (20) being transmission-connected to the first compound oil pump (15), and the second motor (20) being used to drive the first compound oil pump (15) to rotate; a third motor (21), the third motor (21) being drivingly connected to the second compound oil pump (16), and the third motor (21) being used to drive the second compound oil pump (16) to rotate; an oil replenishing motor (22), the oil replenishing motor (22) being in transmission connection with the oil replenishing pump (6), and the oil replenishing motor (22) being used to drive the oil replenishing pump (6) to rotate; a battery (24), the battery (24) being electrically connected to the first motor (19), the second motor (20), the third motor (21) and the fuel replenishment motor (22) respectively; A first internal combustion engine (26) and a first generator (25), wherein the first internal combustion engine (26) is transmission-connected to the generator and is used to drive the first generator (25) to rotate, and the first generator (25) is electrically connected to the battery (24).

7. The boom decoupling hydraulic system according to claim 4, characterized in that: The boom decoupling hydraulic system also includes a drive system, which includes: a first motor (19), the first motor (19) being capable of forward and reverse rotation, the first motor (19) being simultaneously transmission-connected to the first boom oil pump (4) and the second boom oil pump (5), and the first motor (19) being capable of simultaneously driving the first boom oil pump (4) and the second boom oil pump (5) to rotate; a second internal combustion engine (27), the second internal combustion engine (27) being transmission-connected to the first compound oil pump (15) and the second compound oil pump (16) respectively, and the second internal combustion engine (27) being used to drive the first compound oil pump (15) and the second compound oil pump (16) to rotate simultaneously; a second generator (23), the second internal combustion engine (27) being transmission-connected to the second generator (23), and the second internal combustion engine (27) being used to drive the second generator (23) to rotate; an oil replenishing motor (22), the oil replenishing motor (22) being in transmission connection with the oil replenishing pump (6), and the oil replenishing motor (22) being used to drive the oil replenishing pump (6) to rotate; A battery (24), the battery (24) being electrically connected to the first motor (19), the fuel replenishing motor (22) and the second generator (23) respectively.

8. The boom decoupling hydraulic system according to any one of claims 4 to 7, characterized in that: The boom decoupling hydraulic system further comprises: a first valve (32), the first valve (32) being capable of connecting the output end of the first compound oil pump (15) to one of the boom rod chamber (301) and the boom rodless chamber (302), and connecting the oil tank (18) to the other of the boom rod chamber (301) and the boom rodless chamber (302); a second valve (33), the second valve (33) being capable of connecting the output end of the first compound oil pump (15) to one of the bucket rod chamber (201) and the bucket rodless chamber (202), and connecting the oil tank (18) to the other of the bucket rod chamber (201) and the bucket rodless chamber (202); A third valve (34), wherein the third valve (34) is capable of connecting the output end of the second compound oil pump (16) to one of the boom rod chamber (301) and the boom rodless chamber (302), and connecting the oil tank (18) to the other of the boom rod chamber (301) and the boom rodless chamber (302).

9. The boom decoupling hydraulic system according to any one of claims 1 to 7, characterized in that: The boom decoupling hydraulic system further comprises a first oil replenishment check valve (11) and a second oil replenishment check valve (12), wherein the first oil replenishment check valve (11) is connected between the oil replenishment oil circuit (901) and the boom rodless chamber (102), and the first oil replenishment check valve (11) only allows oil to flow from the oil replenishment oil circuit (901) to the boom rodless chamber (102); the second oil replenishment check valve (12) is connected between the oil replenishment oil circuit (901) and the boom rod chamber (101), and the second oil replenishment check valve (12) only allows oil to flow from the oil replenishment oil circuit (901) to the boom rod chamber (101).

10. The boom decoupling hydraulic system according to any one of claims 1 to 7, characterized in that: The boom decoupling hydraulic system further comprises a first overflow valve (13) and a second overflow valve (14), wherein the first overflow valve (13) is connected between the oil replenishing circuit (901) and the boom rodless chamber (102), and the first overflow valve (13) only allows oil to overflow from the boom rodless chamber (102) to the oil replenishing circuit (901); and the second overflow valve (14) is connected between the oil replenishing circuit (901) and the boom rod chamber (101), and the second overflow valve (14) only allows oil to overflow from the boom rod chamber (101) to the oil replenishing circuit (901).

11. An excavator, characterized in that: The excavator comprises a boom decoupling hydraulic system as claimed in any one of claims 1 to 10, wherein the excavator further comprises an excavator body, a boom hinged to the excavator body, a boom arm hinged to the boom, and a bucket hinged to the boom arm, the boom cylinder body of the boom cylinder (1) is hinged to the excavator body, the boom piston rod of the boom cylinder (1) is hinged to the boom, the boom cylinder body of the boom cylinder (3) is hinged to the boom, the boom piston rod of the boom cylinder (3) is hinged to the boom, the bucket cylinder body of the bucket cylinder (2) is hinged to the boom, and the bucket piston rod of the bucket cylinder (2) is hinged to the bucket.

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