A hydraulic system for an integrated drive and recovery excavator and the excavator

Abstract

This invention discloses an integrated hydraulic system for a drive-and-recovery excavator and the excavator itself. The system includes: a first pump motor driven by a first motor, a second pump driven by a second motor, and a third pump driven by a third motor; the first pump motor is connected to a boom valve, which is connected to the boom cylinder; the second pump is connected to a boom regeneration valve, a boom valve, a bucket valve, and a stick valve; the boom regeneration valve is connected to the rodless chamber of the boom cylinder; the boom valve is connected to the boom cylinder; the rod chamber of the boom cylinder is connected to an oil tank via a check valve; the bucket valve is connected to the bucket cylinder; the stick valve is connected to the stick cylinder; and the third pump is connected to the stick valve, which is connected to the stick cylinder. This invention eliminates throttling losses caused by load differences during multi-actuator compound actions, achieves potential energy recovery during boom descent, improves the stability and flexibility of the boom descent process, and avoids cavitation.

Description

Technical Field

[0001] This invention belongs to the field of excavator technology, specifically relating to an integrated hydraulic system for drive and recovery in an excavator and an excavator. Background Technology

[0002] Mainstream excavator hydraulic systems use a centralized oil source for power, with actuator movements controlled by hydraulic multi-way valves, employing a throttling control system. The pressure before the actuator valves is a common rail, determined by the highest load on each actuator, while the pressure after the valves is determined by the load on each actuator. During combined actions, the throttling loss at the valve orifice of the low-load actuator is high. For example, in a dual-pump system, when the boom and stick are used in combined leveling operations, the stick requires a larger flow rate; this results in high throttling losses during multiple actuator combined actions. Furthermore, the reciprocating motion of the excavator's working device generates a significant amount of gravitational potential energy, which is consumed as throttling losses. These two types of throttling losses contribute to increased overall machine fuel consumption. In addition, the boom regeneration flow requirements of small and medium-tonnage excavators and large-tonnage excavators are significantly different when the boom is lowered. Small and medium-tonnage excavators have a lower boom descent flow requirement, which can be met by the hydraulic pump and the replenishing valve. Large-tonnage excavators, on the other hand, have a higher boom descent flow requirement, which cannot be met by the pump and the replenishing valve alone. This difference between small and medium-tonnage excavators and large excavators leads to incompatibility between their operating principles and poor system versatility. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an integrated hydraulic system and excavator for drive and recovery, which eliminates throttling losses caused by load differences during the compound action of multiple actuators, realizes potential energy recovery during boom descent, improves the stability and flexibility of boom descent, and avoids cavitation.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] In a first aspect, a hydraulic system for an integrated excavator drive and recovery is provided, comprising: a first pump motor driven by a first motor, a second pump driven by a second motor, and a third pump driven by a third motor; the oil outlet of the first pump motor is connected to the oil inlet of a boom valve, and the working oil port of the boom valve is connected to the boom cylinder; the oil outlet of the second pump is connected to the oil inlets of a boom regeneration valve, a boom valve, a bucket valve, and a stick valve; the oil outlet of the boom regeneration valve is connected to the rodless chamber of the boom cylinder; the working oil port of the boom valve is connected to the boom cylinder; the rod chamber of the boom cylinder is connected to an oil tank via a check valve; the working oil port of the bucket valve is connected to the bucket cylinder; the working oil port of the stick valve is connected to the stick cylinder; and the oil outlet of the third pump is connected to the oil inlet of the stick valve, and the working oil port of the stick valve is connected to the stick cylinder.

[0006] Furthermore, when the boom is raised, the first pump motor operates in pump mode, and the first motor drives the first pump motor to deliver hydraulic oil through the boom valve to the rodless chamber of the boom cylinder; the second motor drives the second pump to deliver hydraulic oil through the boom valve to the rodless chamber of the boom cylinder; the hydraulic oil in the rod chamber of the boom cylinder enters the oil tank through the return ports of the boom valve and the boom valve.

[0007] Furthermore, when the boom descends and recovers its descent potential energy, the first pump motor operates in motor mode, and the second motor drives the second pump to deliver hydraulic oil through the boom valve two to the rod chamber of the boom cylinder; the hydraulic oil in the rodless chamber of the boom cylinder enters the first pump motor through the boom valve one, and the first pump motor drives the first motor to generate electricity.

[0008] Furthermore, the boom descent speed is controlled by the opening area of ​​the boom valve throttle orifice of boom valve 1 and the boom valve 2 throttle orifice of boom valve 2.

[0009] Furthermore, when the boom descends and recovers its descent potential energy, and the boom itself regenerates its flow, the first pump motor operates in motor mode, and the second motor drives the second pump to deliver hydraulic oil through the boom's second valve to the rod chamber of the boom cylinder. The hydraulic oil in the rodless chamber of the boom cylinder is divided into two parts. One part enters the first pump motor through the boom's first valve, which drives the first motor to generate electricity. The other part merges with the hydraulic oil output from the second pump through the boom regeneration valve and is then delivered to the rod chamber of the boom cylinder through the boom's second valve.

[0010] Furthermore, the boom descent speed is controlled by the boom valve throttle orifice of boom valve 1, the boom valve throttle orifice of boom valve 2, and the opening area of ​​the boom regeneration valve.

[0011] Furthermore, when the boom descends and recovers its descent potential energy, and simultaneously when the boom regenerates flow to the stick and bucket, the first pump motor operates in motor mode, and the second motor drives the second pump to deliver hydraulic oil through the boom valve two to the rod chamber of the boom cylinder; the hydraulic oil in the rodless chamber of the boom cylinder is divided into two parts, one part of which enters the first pump motor through the boom valve one, and drives the first motor to generate electricity through the first pump motor, and the other part merges with the hydraulic oil output from the second pump through the boom regeneration valve, and then drives the stick cylinder through the stick valve two and the bucket cylinder through the bucket valve.

[0012] Furthermore, the boom descent speed is controlled by the boom valve throttle orifice of boom valve 1, the boom valve throttle orifice of boom valve 2, and the opening area of ​​the boom regeneration valve.

[0013] Furthermore, during the boom's descent, the rod chamber of the boom cylinder receives oil from the tank via a one-way valve.

[0014] Furthermore, when the stick retracts, the second motor drives the second pump to deliver hydraulic oil to the rodless chamber of the stick cylinder through the second stick valve; the third motor drives the third pump to deliver hydraulic oil to the rodless chamber of the stick cylinder through the first stick valve; the hydraulic oil in the rod chamber of the stick cylinder enters the oil tank through the throttling ports of the first stick valve and the second stick valve.

[0015] Furthermore, when the boom swings outward, the second motor drives the second pump to deliver hydraulic oil to the rod chamber of the boom cylinder through the boom valve 2; the third motor drives the third pump to deliver hydraulic oil to the rod chamber of the boom cylinder through the boom valve 1; the hydraulic oil in the rodless chamber of the boom cylinder enters the oil tank through the throttle ports of the boom valve 1 and the boom valve 2.

[0016] Furthermore, when the bucket retracts, the second motor drives the second pump to deliver hydraulic oil through the bucket valve to the rodless chamber of the bucket cylinder, and the hydraulic oil in the rod chamber of the bucket cylinder enters the oil tank through the throttle port of the bucket valve.

[0017] Furthermore, when the bucket swings outward, the second motor drives the second pump to deliver hydraulic oil through the bucket valve to the rod chamber of the bucket cylinder, and the hydraulic oil in the rodless chamber of the bucket cylinder enters the oil tank through the throttle port of the bucket valve.

[0018] In a second aspect, an excavator is provided, the excavator being equipped with the integrated drive and recovery excavator hydraulic system described in the first aspect.

[0019] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention uses a first pump motor driven by a first motor, a second pump driven by a second motor, and a third pump driven by a third motor; the oil outlet of the first pump motor is connected to the oil inlet of the boom valve, and the working oil port of the boom valve is connected to the boom cylinder; the oil outlet of the second pump is connected to the oil inlets of the boom regeneration valve, the boom valve, the bucket valve, and the stick valve; the oil outlet of the boom regeneration valve is connected to the rodless chamber of the boom cylinder; the working oil of the boom valve... The boom cylinder is connected to the boom valve port; the boom cylinder's rod chamber is connected to the oil tank via a check valve; the bucket valve's working port is connected to the bucket cylinder; the boom valve's working port is connected to the boom cylinder; the third pump's outlet is connected to the boom valve's inlet, and the boom valve's working port is connected to the boom cylinder; this eliminates the throttling loss caused by load differences during multi-actuator compound actions, realizes potential energy recovery during boom descent, improves the stability and flexibility of boom descent, and avoids cavitation. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the hydraulic system for an integrated drive and recovery excavator provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the working state of each valve in the system when the boom falls and the potential energy of the boom's descent is recovered in an embodiment of the present invention.

[0022] Figure 3 This is a schematic diagram of the working state of each valve in the system when the boom falls and recovers the potential energy of the boom's descent, while the boom's own flow is regenerated, according to an embodiment of the present invention.

[0023] Figure 4 This is a schematic diagram of the working status of each valve in the system when the boom falls and recovers the potential energy of the boom's descent, and at the same time the flow of the boom to the stick and bucket is regenerated.

[0024] In the diagram: 1. First motor; 101. Pilot valve; 102. Electromagnet for boom valve 1 shifting; 103. Electromagnet for boom valve 1 shifting; 104. Electromagnet for boom valve 2 shifting; 105. Electromagnet for boom valve 2 shifting; 106. Solenoid 1 for bucket valve; 107. Solenoid 2 for bucket valve; 108. Solenoid 1 for stick valve 2; 109. Solenoid 2 for stick valve 2; 110. Solenoid 1 for stick valve 1; 11 1. Solenoid 2, boom valve 1; 2. Second motor; 3. Third motor; 4. First pump; 5. Second pump; 6. Third pump; 7. Boom regeneration valve; 8. Boom valve 1; 9. Boom valve 2; 10. Bucket valve; 11. Boom valve 2; 12. Boom valve 1; 13. Boom cylinder; 14. Bucket cylinder; 15. Boom cylinder; 16. Check valve; 17. Boom valve 1 throttle orifice; 18. Boom valve 2 throttle orifice; 19. Oil passage. Detailed Implementation

[0025] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0026] Example 1:

[0027] like Figure 1 As shown, a hydraulic system for an integrated drive and recovery excavator includes: a first pump motor 4 driven by a first motor 1, a second pump 5 driven by a second motor 2, and a third pump 6 driven by a third motor 3. The first pump motor 4 has two operating modes: when operating in pump mode, the first motor 1 drives the first pump motor 4 to deliver hydraulic oil from the oil tank to designated working parts; when operating in motor mode, hydraulic oil enters the first pump motor 4 and drives the first motor 1 to generate electricity.

[0028] The oil outlet of the first pump motor 4 is connected to the oil inlet of the boom valve 8, and the working oil port of the boom valve 8 is connected to the boom cylinder 13; the oil outlet of the second pump 5 is connected to the oil inlets of the boom regeneration valve 7, the boom valve 9, the bucket valve 10, and the stick valve 11 respectively; the oil outlet of the boom regeneration valve 7 is connected to the rodless chamber of the boom cylinder 13; the working oil port of the boom valve 9 is connected to the boom cylinder 13; the rod chamber of the boom cylinder 13 is connected to the oil tank through the check valve 16; the working oil port of the bucket valve 10 is connected to the bucket cylinder 14; the working oil port of the stick valve 11 is connected to the stick cylinder 15; the oil outlet of the third pump 6 is connected to the oil inlet of the stick valve 12, and the working oil port of the stick valve 12 is connected to the stick cylinder 15.

[0029] In this invention, the boom cylinder 13, stick cylinder 15, and bucket cylinder 14 are each supplied with oil by a separate hydraulic pump, achieving independent control of the actuators and eliminating throttling losses caused by load differences in the compound actions of multiple actuators. During boom descent, the high-pressure oil in the rodless chamber of the boom cylinder 13 can drive the first pump motor 4 to generate electricity, thus storing the potential energy of the boom descent. To prevent the boom speed from slowing down or becoming unstable during energy storage, a boom rodless chamber return oil pressure control position is provided to control the return oil flow rate, ensuring a stable and rapid boom descent. Furthermore, the boom rodless chamber is connected to a boom regeneration valve 7. On large excavators, during boom descent, the flow rate from the boom rodless chamber is regenerated to the boom rod chamber via the boom regeneration valve 7, preventing the boom from sucking in cavitation. Simultaneously, the flow rate from the boom rodless chamber can be regenerated to the stick or bucket via the boom regeneration valve 7. This improves energy utilization and solves the problem of slow speed due to heavy load when driving the pump motor during boom descent.

[0030] The specific operating conditions in this invention are described below.

[0031] (1) Boom lifting:

[0032] When the boom is raised, the first pump motor 4 operates in pump mode, and the first motor 1 drives the first pump motor 4 to work; the second motor 2 drives the second pump 5 to work, the boom valve 1 switching electromagnet 103 and the boom valve 2 switching electromagnet 105 are energized, and the boom valve 1 and boom valve 9 operate in their upper positions. The first pump motor 4 and the second pump 5 are both connected to the rodless chamber of the boom cylinder 13. The two pumps merge after the two valves, and the power oil enters the rodless chamber of the boom cylinder 13. The oil in the rod chamber of the boom cylinder 13 enters the oil tank through the return ports of the boom valve 1 and boom valve 2. The dual-pump combined drive can meet the operating requirements of the excavator boom.

[0033] (2) There are three situations when the boom is falling:

[0034] In the first scenario, when the boom lowers and recovers its descent potential energy, the first pump motor 4 operates in motor mode, such as... Figure 2 As shown, when the boom valve 1 switching solenoid 102 is energized, it pushes the boom valve 8 to work in lower working position A and lower working position B. When the boom valve 2 switching solenoid 104 is energized, the boom valve 9 operates in the lower position. The second motor 2 drives the second pump 5 as the oil source for the boom cylinder 13 to descend. The oil enters the rod chamber of the boom cylinder 13 through the boom valve 9. At the same time, the rod chamber of the boom cylinder 13 is replenished with oil from the oil tank through the check valve 16 to prevent cavitation. The oil in the rodless chamber of the boom cylinder 13 is supplied through... Most of the flow from boom valve 8 enters the first pump motor 4 (motor mode), driving the first motor 1 to generate electricity, converting the boom's descent potential energy into electrical energy, thus achieving boom descent energy recovery. Since the first pump motor 4 drives the first motor 1 under a large load, the boom's descent speed and stability may be affected. This can be addressed by adjusting the opening areas of boom valve 17 and boom valve 2 (throttle orifice 18) to control the flow rate into the first pump motor 4, ensuring controlled boom descent speed and stability. Simultaneously, by proportionally controlling the return oil areas of boom valve 17 and boom valve 2 (throttle orifice 18), the pressure in the boom's rodless chamber is proportionally adjusted to ensure that the boom's descent speed and stability meet the overall machine control requirements.

[0035] The second scenario involves the boom descending and recovering its descent potential energy, while simultaneously regenerating the boom's own flow rate. In this scenario, the first pump motor 4 operates in motor mode, such as... Figure 3 As shown, when the boom valve 1 switching solenoid 102 is energized, it pushes the boom valve 8 to work in the lower working position A and the lower working position B. When the boom valve 2 switching solenoid 104 is energized, the boom valve 9 works in the lower position. The second motor 2 drives the second pump 5 as the oil source for the boom cylinder 13 to descend. The oil enters the rod chamber of the boom cylinder 13 through the boom valve 9. At the same time, the rod chamber of the boom cylinder 13 is replenished with oil from the oil tank through the check valve 16 to prevent cavitation. The oil in the rodless chamber of the boom cylinder 13 flows through the boom... Valve 8 allows most of the flow to enter the first pump motor 4 (motor mode), driving the first motor 1 to generate electricity, converting the boom's descent potential energy into electrical energy, thus recovering the boom's descent energy. Since the first pump motor 4 operates under a large load, the boom's descent speed and stability may be affected. This can be controlled by adjusting the opening area of ​​the boom valve's throttle orifice 17, the boom valve's throttle orifice 18, and the boom regeneration valve 7, ensuring controlled boom descent speed and stability. Simultaneously, the pilot valve 101 of the boom regeneration valve 7 is energized, allowing a portion of the flow from the rodless chamber of the boom cylinder 13 to enter the oil passage 19 through the boom regeneration valve 7, merging with the flow from the second pump 5. This merged flow then enters the rod chamber of the boom cylinder 13 through the boom valve 9, regenerating the flow from the rodless chamber of the boom cylinder 13 to the rod chamber, preventing airflow from being sucked in during the descent of a large-tonnage excavator's boom.

[0036] The third scenario involves the boom descending and recovering its descent potential energy, while simultaneously regenerating flow from the boom to the stick and bucket. In this scenario, the first pump motor 4 operates in motor mode, such as... Figure 4 As shown, when the boom valve 1 switching solenoid 102 is energized, it pushes the boom valve 8 to work in the lower working position A and the lower working position B. When the boom valve 2 switching solenoid 104 is energized, the boom valve 9 works in the lower position. The second motor 2 drives the second pump 5 as the oil source for the boom cylinder 13 to descend. The oil enters the rod chamber of the boom cylinder 13 through the boom valve 9. At the same time, the rod chamber of the boom cylinder 13 is replenished with oil from the oil tank through the check valve 16 to prevent cavitation. The oil in the rodless chamber of the boom cylinder 13 flows through the boom... Valve 8 allows most of the flow to enter the first pump motor 4 (motor mode), driving the first motor 1 to generate electricity, converting the boom's descent potential energy into electrical energy, thus recovering the boom's descent energy. Since the first pump motor 4 operates under a large load, the boom's descent speed and stability may be affected. This can be controlled by adjusting the opening area of ​​the boom valve 17, boom valve 2 throttle orifice 18, and boom regeneration valve 7 to regulate the flow entering the first pump motor 4, ensuring controlled boom descent speed and stability. Simultaneously, the pilot valve 101 of the boom regeneration valve 7 is energized, allowing a portion of the flow from the rodless chamber of the boom cylinder 13 to enter the oil passage 19 through the boom regeneration valve 7, merging with the flow from the second pump 5. This merged flow can then enter the boom cylinder 15 and bucket cylinder 14 through the stick valve 11 and bucket valve 10, respectively, regenerating the flow from the rodless chamber of the boom cylinder 13 to the stick cylinder 15 and bucket cylinder 14.

[0037] Pole fighting techniques:

[0038] During the boom retraction process, the second solenoid 109 of the boom valve 2 and the second solenoid 111 of the boom valve 1 are energized, and both the boom valve 12 and the boom valve 2 are in their upper positions. The second motor 2 drives the second pump 5, and the third motor 3 drives the third pump 6. The oil enters the rodless chamber of the boom cylinder 15 through the boom valve 12 and the boom valve 2 11, and the oil in the rod chamber of the boom cylinder 15 enters the oil tank through the throttling port of the boom valve 12 and the boom valve 2 11.

[0039] During the outward swing of the boom, the boom valve electromagnet 108 and the boom valve electromagnet 110 are energized, and both boom valve 12 and boom valve 11 are in the lower position. The second motor 2 drives the second pump 5, and the third motor 3 drives the third pump 6. The oil enters the rod chamber of the boom cylinder 15 through boom valve 12 and boom valve 11, and the oil in the rodless chamber of the boom cylinder 15 enters the oil tank through the throttling port of boom valve 12 and boom valve 11.

[0040] Bucket action:

[0041] During the bucket retraction process, the second electromagnet 107 of the bucket valve is energized, the bucket valve 10 operates in the upper position, the second motor 2 drives the second pump 5, and the oil flows into the rodless chamber of the bucket cylinder 14 through the bucket valve 10. The oil in the rod chamber of the bucket cylinder 14 flows into the oil tank through the throttle port of the bucket valve 10.

[0042] During the outward swing of the bucket, the bucket valve solenoid 106 is energized, the bucket valve 10 operates in the lower position, the second motor 2 drives the second pump 5, and the oil flows through the bucket valve 10 into the rod chamber of the bucket cylinder 14. The oil in the rodless chamber of the bucket cylinder 14 flows into the oil tank through the throttle port of the bucket valve 10.

[0043] This invention eliminates throttling losses caused by load differences during multi-actuator compound operations. By setting up a boom regeneration valve, when the boom descends, the high-pressure oil in the rodless chamber can be regenerated across the loop to supply the stick and bucket. In this way, part of the flow in the boom's rodless chamber is used to drive the pump motor for energy recovery, and the other part of the flow can be supplied to the stick and bucket. This not only solves the problem of slow and unstable boom speed caused by driving the pump motor with all the flow, but also improves the system's energy utilization rate. At the same time, the boom descent speed can also achieve its own flow regeneration, solving the problem of slow and unstable boom speed caused by driving the pump motor with all the flow, and also avoiding the problem of air suction during the descent of large excavators. The boom oil supply is a pump-motor device. When the boom descends, the high-pressure oil in the rodless chamber drives the motor to generate electrical energy, storing the potential energy of the boom descent. At the same time, the return oil throttle orifice area of ​​the boom valve 1 and boom valve 2 can be controlled by the program to more flexibly set the boom descent speed and meet more working conditions. A boom descent replenishment valve (one-way valve 16) is set to supplement the return oil flow to the boom rod chamber to prevent the boom from sucking in cavitation. By adopting different control strategies, multiple electric drive power sources combined with electro-hydraulic proportional valves can meet the needs of different working conditions of hydraulic excavators, with high control freedom and good flexibility. The boom and stick confluence circuit is designed to meet the flow requirements of single action and compound action, realizing more precise control.

[0044] Example 2:

[0045] Based on the integrated drive and recovery excavator hydraulic system described in Embodiment 1, this embodiment provides an excavator equipped with the integrated drive and recovery excavator hydraulic system described in Embodiment 1.

[0046] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A drive-recovery integrated hydraulic system for a shovel, characterized by comprising: include: The first pump motor (4) is driven by the first motor (1), the second pump (5) is driven by the second motor (2), and the third pump (6) is driven by the third motor (3). The oil outlet of the first pump motor (4) is connected to the oil inlet of the boom valve (8), and the working oil port of the boom valve (8) is connected to the boom cylinder (13). The oil outlet of the second pump (5) is connected to the oil inlet of the boom regeneration valve (7), boom valve 2 (9), bucket valve (10), and stick valve 2 (11), respectively; the oil outlet of the boom regeneration valve (7) is connected to the rodless chamber of the boom cylinder (13); the working oil port of the boom valve 2 (9) is connected to the boom cylinder (13); the rod chamber of the boom cylinder (13) is connected to the oil tank through a one-way valve (16); the working oil port of the bucket valve (10) is connected to the bucket cylinder (14); and the working oil port of the stick valve 2 (11) is connected to the stick cylinder (15). The outlet of the third pump (6) is connected to the inlet of the boom valve (12), and the working port of the boom valve (12) is connected to the boom cylinder (15).

2. The integrated drive and recovery hydraulic system for excavators according to claim 1, characterized in that, When the boom is raised, the first pump motor (4) operates in pump mode. The first motor (1) drives the first pump motor (4) to deliver hydraulic oil through the boom valve (8) to the rodless chamber of the boom cylinder (13). The second motor (2) drives the second pump (5) to deliver hydraulic oil through the boom valve (9) to the rodless chamber of the boom cylinder (13). The hydraulic oil in the rod chamber of the boom cylinder (13) enters the oil tank through the return ports of the boom valve (8) and the boom valve (9).

3. The integrated drive and recovery hydraulic system for excavators according to claim 1, characterized in that, When the boom falls and recovers the potential energy of the boom's descent, the first pump motor (4) operates in motor mode, and the second motor (2) drives the second pump (5) to deliver hydraulic oil through the boom valve (9) to the rod chamber of the boom cylinder (13); the hydraulic oil in the rodless chamber of the boom cylinder (13) enters the first pump motor (4) through the boom valve (8), and the first pump motor (4) drives the first motor (1) to generate electricity.

4. The drive-recovery integrated hydraulic system of claim 3, wherein The boom descent speed is controlled by the opening area of ​​the boom valve throttle orifice (17) of boom valve 1 (8) and the boom valve throttle orifice (18) of boom valve 2 (9).

5. The integrated drive and recovery hydraulic system for excavators according to claim 1, characterized in that, When the boom descends and recovers its descent potential energy, and the boom itself regenerates its flow, the first pump motor (4) operates in motor mode, and the second motor (2) drives the second pump (5) to deliver hydraulic oil to the rod chamber of the boom cylinder (13) via the boom second valve (9). The hydraulic oil in the rodless chamber of the boom cylinder (13) is divided into two parts. One part enters the first pump motor (4) via the boom first valve (8) and drives the first motor (1) to generate electricity. The other part merges with the hydraulic oil output by the second pump (5) via the boom regeneration valve (7) and is then delivered to the rod chamber of the boom cylinder (13) via the boom second valve (9).

6. The integrated drive and recovery hydraulic system for excavators according to claim 5, characterized in that, The boom descent speed is controlled by the boom valve throttle orifice (17) of boom valve 1 (8), the boom valve throttle orifice (18) of boom valve 2 (9), and the opening area of ​​boom regeneration valve (7).

7. The integrated drive and recovery hydraulic system for excavators according to claim 1, characterized in that, When the boom descends and recovers its descent potential energy, and the boom regenerates flow to the stick and bucket, the first pump motor (4) operates in motor mode, and the second motor (2) drives the second pump (5) to deliver hydraulic oil to the rod chamber of the boom cylinder (13) via the boom valve (9). The hydraulic oil in the rodless chamber of the boom cylinder (13) is divided into two parts. One part enters the first pump motor (4) via the boom valve (8) and drives the first motor (1) to generate electricity. The other part merges with the hydraulic oil output by the second pump (5) via the boom regeneration valve (7), and then drives the stick cylinder (15) via the stick valve (11) and the bucket cylinder (14) via the bucket valve (10).

8. The drive-recovery integrated hydraulic system of claim 7, wherein, The boom descent speed is controlled by the boom valve throttle orifice (17) of boom valve 1 (8), the boom valve throttle orifice (18) of boom valve 2 (9), and the opening area of ​​boom regeneration valve (7).

9. The integrated drive-recovery hydraulic system for a shovel according to any one of claims 3 to 8, characterized in that, During the boom lowering process, the rod chamber of the boom cylinder (13) is replenished with oil from the oil tank through the check valve (16).

10. The integrated drive and recovery hydraulic system for excavators according to claim 1, characterized in that, When the stick retracts, the second motor (2) drives the second pump (5) to deliver hydraulic oil through the second stick valve (11) to the rodless chamber of the stick cylinder (15); the third motor (3) drives the third pump (6) to deliver hydraulic oil through the first stick valve (12) to the rodless chamber of the stick cylinder (15); the hydraulic oil in the rod chamber of the stick cylinder (15) enters the oil tank through the throttling ports of the first stick valve (12) and the second stick valve (11).

11. The integrated drive and recovery hydraulic system for excavators according to claim 1, characterized in that, When the boom swings outward, the second motor (2) drives the second pump (5) to deliver hydraulic oil through the boom second valve (11) to the rod chamber of the boom cylinder (15); the third motor (3) drives the third pump (6) to deliver hydraulic oil through the boom first valve (12) to the rod chamber of the boom cylinder (15); the hydraulic oil in the rodless chamber of the boom cylinder (15) enters the oil tank through the throttling ports of the boom first valve (12) and the boom second valve (11).

12. The integrated drive and recovery excavator hydraulic system according to claim 1, characterized in that, When the bucket retracts, the second motor (2) drives the second pump (5) to deliver hydraulic oil through the bucket valve (10) to the rodless chamber of the bucket cylinder (14). The hydraulic oil in the rod chamber of the bucket cylinder (14) enters the oil tank through the throttle port of the bucket valve (10).

13. The integrated drive and recovery hydraulic system for excavators according to claim 1, characterized in that, When the bucket swings outward, the second motor (2) drives the second pump (5) to deliver hydraulic oil through the bucket valve (10) to the rod chamber of the bucket cylinder (14), and the hydraulic oil in the rodless chamber of the bucket cylinder (14) enters the oil tank through the throttle port of the bucket valve (10).

14. An excavator characterized by comprising: The excavator is equipped with the integrated drive and recovery hydraulic system of the excavator as described in any one of claims 1 to 13.

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