Energy recovery system for excavator based on accumulator assisted oil replenishment

Abstract

The application relates to an excavator energy recovery system based on an accumulator-assisted oil supplementing function and relates to the technical field of excavator driving. The system comprises a hydraulic cylinder, a three-position four-way electromagnetic valve, a hydraulic pump, a motor connected to the hydraulic pump in a transmission mode, a first two-position two-way electromagnetic valve connected to an oil return port T of the three-position four-way electromagnetic valve, a second two-position two-way electromagnetic valve connected between the first two-position two-way electromagnetic valve and a hydraulic oil tank, a hydraulic accumulator connected to the first two-position two-way electromagnetic valve, a third two-position two-way electromagnetic valve connected to the hydraulic accumulator and a fourth two-position two-way electromagnetic valve. The oil inlet of the hydraulic pump is connected to the hydraulic oil tank and the fourth two-position two-way electromagnetic valve. The oil outlets A and B of the three-position four-way electromagnetic valve are respectively connected to the rod cavity and the rodless cavity of the hydraulic cylinder, and the oil inlet P is connected to the oil outlet of the hydraulic pump and the third two-position two-way electromagnetic valve. When the hydraulic cylinder is retracted, energy is stored through the hydraulic accumulator. When the hydraulic cylinder is extended, oil is supplemented through the hydraulic accumulator.

Description

Technical Field

[0001] This invention relates to the field of excavator drive technology, and more specifically, to an excavator energy recovery system based on accumulator-assisted oil replenishment. Background Technology

[0002] In the field of construction machinery, especially in earthmoving, mining, and road construction, excavators are crucial pieces of equipment. When performing delicate tasks such as leveling and slope repair, they place extremely high demands on the response speed and control precision of the hydraulic system. However, in traditional pump control systems, when the hydraulic pump starts, the outlet pressure needs to be re-established. Due to internal leakage in the hydraulic pump and the compressibility of the hydraulic fluid, this process results in a dead zone in the pump's output flow response to the input speed. This increases the system's steady-state error and causes significant response delays, severely impacting the accuracy and efficiency of operations.

[0003] Furthermore, the hydraulic pump, the core power component of an excavator, is prone to negative pressure at its suction port under high-speed operation, leading to cavitation and air intake. This problem not only causes hydraulic oil atomization, reducing system transmission performance and stability, but in severe cases, it can also cause abnormal wear or even damage to the equipment due to air intake, posing a direct threat to the reliability and service life of the equipment.

[0004] A more prominent problem is that traditional excavator hydraulic systems have long suffered from inherent defects such as high energy consumption and low energy utilization. In operating conditions such as boom lowering, a significant amount of hydraulic energy is dissipated through throttling or overflow, failing to be effectively recovered and reused. This energy waste not only increases the operating costs of the equipment but also contradicts the current trend in the construction machinery industry towards green, energy-saving, and sustainable development. Therefore, how to achieve high-frequency system response, avoid damage to key components, and efficiently recover and utilize energy has become an urgent technical challenge to be solved. Summary of the Invention

[0005] This invention provides an excavator energy recovery system based on accumulator-assisted oil replenishment, which aims to improve at least one of the above-mentioned technical problems.

[0006] To address the aforementioned technical problems, this invention provides an excavator energy recovery system based on accumulator-assisted oil replenishment. The system includes a hydraulic cylinder, a three-position four-way solenoid valve, a hydraulic pump, a motor connected to the hydraulic pump, a first two-position two-way solenoid valve with a pipeline connected to the return port T of the three-position four-way solenoid valve, a second two-position two-way solenoid valve with a pipeline connected between the first two-position two-way solenoid valve and the hydraulic oil tank, a hydraulic accumulator with a pipeline connected to the first two-position two-way solenoid valve, and a third two-position two-way solenoid valve and a fourth two-position two-way solenoid valve with pipelines connected to the hydraulic accumulator. The inlet pipeline of the hydraulic pump is connected to the hydraulic oil tank and the fourth two-position two-way solenoid valve. The outlet ports A and B of the three-position four-way solenoid valve are respectively connected to the rod-side and rodless-side chambers of the hydraulic cylinder, and the inlet port P is connected to the outlet port of the hydraulic pump and the third two-position two-way solenoid valve.

[0007] When the hydraulic cylinder extends: the electric motor drives the hydraulic pump to supply oil to the rodless chamber. If the hydraulic pump's start-up time does not exceed the first preset time, the first and third two-position two-way solenoid valves are activated. If the hydraulic pump's start-up time exceeds the first preset time, the first, second, and fourth two-position two-way solenoid valves are activated.

[0008] When the hydraulic cylinder retracts: The electric motor drives the hydraulic pump to supply oil to the rod chamber. If Zyr > Z, the first and second position two-way solenoid valves are activated. If Zyr ≤ Z, the first and second position two-way solenoid valves and the second and second position two-way solenoid valves are activated. Here, Zyr is the pressure in the rodless chamber of the hydraulic cylinder, and Z is the pressure in the hydraulic accumulator.

[0009] As a further optimization, the specific steps for the hydraulic cylinder to extend include:

[0010] An electric motor drives a hydraulic pump to deliver oil, energizing the control terminal a of a three-position four-way solenoid valve. This connects the inlet port P and outlet port A, and the outlet port B and return port T. This allows the hydraulic pump to deliver oil to the rodless chamber of the hydraulic cylinder and to return oil to the rod chamber.

[0011] Determine whether the hydraulic pump startup time exceeds the first preset time.

[0012] When it is determined that the hydraulic pump start-up time has not exceeded the first preset time, the first two-position two-way solenoid valve and the third two-position two-way solenoid valve are opened so that the hydraulic oil of the hydraulic accumulator is sent to the rodless chamber of the hydraulic cylinder through the third two-position two-way solenoid valve, and the return oil of the rod chamber of the hydraulic cylinder is sent to the third two-position two-way solenoid valve through the three-position four-way solenoid valve and the first two-position two-way solenoid valve, thereby reducing the frequency response time of the hydraulic system.

[0013] When it is determined that the hydraulic pump start-up time exceeds the first preset time, the first two-position two-way solenoid valve, the second two-position two-way solenoid valve, and the fourth two-position two-way solenoid valve are activated so that the hydraulic oil in the hydraulic accumulator is delivered to the oil inlet of the hydraulic pump through the fourth two-position two-way solenoid valve to achieve auxiliary oil replenishment.

[0014] As a further optimization, the specific steps for the hydraulic cylinder retraction include:

[0015] An electric motor drives a hydraulic pump to deliver oil, energizing the control terminal b of a three-position four-way solenoid valve. This connects the inlet port P and outlet port B, and the outlet port A and return port T. This allows the hydraulic pump to deliver oil to the rod chamber of the hydraulic cylinder and return oil to the rodless chamber.

[0016] The pressure Zyr in the rodless chamber of the hydraulic cylinder and the pressure Z in the hydraulic accumulator are compared.

[0017] When Zyr > Z, it is determined whether the pressure Z of the hydraulic accumulator is less than the pressure threshold. If so, the first and second position two-way solenoid valves are activated so that the hydraulic oil in the rodless chamber of the hydraulic cylinder can flow to the hydraulic accumulator for energy storage through the first and second position two-way solenoid valves and the third check valve.

[0018] When it is determined that Zyr≤Z, or when it is determined that Z≥pressure threshold, the first two-position two-way solenoid valve and the second two-position two-way solenoid valve are activated so that the hydraulic oil in the rodless chamber of the hydraulic cylinder flows to the hydraulic oil tank through the first two-position two-way solenoid valve and the second two-position two-way solenoid valve.

[0019] As a further optimization, the three-position four-way solenoid valve includes an inlet port P, an outlet port A, an outlet port B, and a return port T. The three-position four-way solenoid valve is constructed such that when control terminal a is energized, inlet port P is connected to outlet port A, and return port T is connected to outlet port B. When control terminal b is energized, inlet port P is connected to outlet port B, and return port T is connected to outlet port A. When the three-position four-way solenoid valve is in the intermediate position, the ports are not interconnected.

[0020] The output shaft of the electric motor is connected to the hydraulic pump to drive the hydraulic pump to work.

[0021] The return port T of the three-position four-way solenoid valve is connected to the inlet of the first two-position two-way solenoid valve. The outlet of the first two-position two-way solenoid valve is connected to the hydraulic port of the hydraulic accumulator and the inlet of the second two-position two-way solenoid valve. The outlet of the second two-position two-way solenoid valve is connected to the hydraulic oil tank.

[0022] The hydraulic accumulator's hydraulic port is connected to the inlet of the third two-position two-way solenoid valve and the fourth two-position two-way solenoid valve. The outlet of the third two-position two-way solenoid valve is connected to the outlet of the hydraulic pump. The outlet of the fourth two-position two-way solenoid valve is connected to the inlet of the hydraulic pump.

[0023] As a further optimization, the excavator energy recovery system based on accumulator-assisted oil replenishment also includes a first check valve and a second check valve.

[0024] The inlet of the first check valve is connected to the hydraulic oil tank. The outlet of the first check valve is connected to the inlet of the hydraulic pump.

[0025] The inlet of the second check valve is connected to the outlet of the hydraulic pump. The outlet of the second check valve is connected to the inlet P of the three-position four-way solenoid valve.

[0026] As a further optimization, the excavator energy recovery system based on accumulator-assisted oil replenishment also includes a first overflow valve and a second overflow valve.

[0027] The inlet pipe of the first relief valve is connected to the outlet of the second check valve. The outlet of the first relief valve is connected to the hydraulic oil tank.

[0028] The inlet of the second relief valve is connected to the hydraulic port of the hydraulic accumulator. The outlet of the second relief valve is connected to the hydraulic oil tank.

[0029] As a further optimization, the excavator energy recovery system based on accumulator-assisted oil replenishment also includes a third check valve. The inlet of the third check valve is connected to the outlet of the first two-position two-way solenoid valve and the inlet of the second two-position two-way solenoid valve. The outlet of the third check valve is connected to the inlet of the third two-position two-way solenoid valve, the inlet of the fourth two-position two-way solenoid valve, and the hydraulic port of the hydraulic accumulator.

[0030] As a further optimization, the excavator energy recovery system based on accumulator-assisted oil replenishment also includes a fourth check valve and a fifth check valve.

[0031] The inlet of the fourth check valve is connected to the outlet of the third two-position two-way solenoid valve. The outlet of the fourth check valve is connected to the inlet P of the three-position four-way solenoid valve.

[0032] The inlet of the fifth check valve is connected to the outlet of the fourth two-position two-way solenoid valve. The outlet of the fifth check valve is connected to the inlet of the hydraulic pump.

[0033] As a further optimization, the first two-position two-way solenoid valve, the second two-position two-way solenoid valve, the third two-position two-way solenoid valve, and the fourth two-position two-way solenoid valve are all structures without exhaust ports.

[0034] As a further optimization, the steps for extending the hydraulic cylinder include: closing all solenoid valves after the hydraulic cylinder has extended to its full position.

[0035] As a further optimization, the steps for retracting the hydraulic cylinder include: closing all solenoid valves after the hydraulic cylinder has retracted into place.

[0036] This application also provides an excavator that includes the excavator energy recovery system based on accumulator-assisted refueling as described in any paragraph of the first aspect.

[0037] By adopting the above technical solution, the present invention can achieve the following technical effects:

[0038] This invention significantly improves the performance and energy efficiency of excavator hydraulic systems by introducing a hydraulic accumulator and its associated valve assembly and control logic. Its core benefits lie in achieving high-frequency response and energy saving: when the hydraulic pump starts or requires rapid response, the accumulator can release pressurized oil to directly or collaboratively drive the hydraulic cylinder, effectively shortening the system's pressure build-up and response time, and improving operational accuracy and efficiency. Simultaneously, when the hydraulic cylinder retracts, the system can recover the hydraulic oil in its rodless chamber and store it in the accumulator. The stored energy can be used for auxiliary drive or to replenish the hydraulic pump in subsequent operations, thereby reducing energy waste and suppressing pump cavitation, protecting critical components. Furthermore, by optimizing the oil circuit design and installing check valves and relief valves, the efficiency and isolation of the energy recovery and release paths are ensured, improving the reliability and safety of the entire system. Attached Figure Description

[0039] To more clearly illustrate the technical solutions of the specific embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the high-frequency response energy recovery system for excavators.

[0041] Figure 2 This is a logic block diagram of the control method for the high-frequency response energy recovery system of an excavator.

[0042] The markings in the diagram are: 1-Hydraulic oil tank, 2-First check valve, 3-Hydraulic pump, 4-Motor, 5-Second check valve, 6-First relief valve, 7-Three-position four-way solenoid valve, 8-Hydraulic cylinder, 9-First two-position two-way solenoid valve, 10-Second two-position two-way solenoid valve, 11-Third check valve, 12-Fourth check valve, 13-Third two-position two-way solenoid valve, 14-Fifth check valve, 15-Fourth two-position two-way solenoid valve, 16-Hydraulic accumulator, 17-Second relief valve. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0044] Example 1, by Figures 1 to 2 As shown, this embodiment of the invention provides an excavator energy recovery system based on accumulator-assisted oil replenishment, comprising a hydraulic cylinder 8, a three-position four-way solenoid valve 7, a hydraulic pump 3, a motor 4 connected to the hydraulic pump 3, a first two-position two-way solenoid valve 9 connected to the return port T of the three-position four-way solenoid valve 7, a second two-position two-way solenoid valve 10 connected between the first two-position two-way solenoid valve 9 and the hydraulic oil tank 1, a hydraulic accumulator 16 connected to the first two-position two-way solenoid valve 9, and a third two-position two-way solenoid valve 13 and a fourth two-position two-way solenoid valve 15 connected to the hydraulic accumulator 16. The inlet pipe of the hydraulic pump 3 is connected to the hydraulic oil tank 1 and the fourth two-position two-way solenoid valve 15. The outlet ports A and B of the three-position four-way solenoid valve 7 are respectively connected to the rod chamber and rodless chamber of the hydraulic cylinder 8, and the inlet port P is connected to the outlet port of the hydraulic pump 3 and the third two-position two-way solenoid valve 13.

[0045] When hydraulic cylinder 8 extends: motor 4 drives hydraulic pump 3 to supply oil to the rodless chamber. If the start time of hydraulic pump 3 does not exceed the first preset time, the first two-position two-way solenoid valve 9 and the third two-position two-way solenoid valve 13 are activated. If the start time of hydraulic pump 3 exceeds the first preset time, the first two-position two-way solenoid valve 9, the second two-position two-way solenoid valve 10, and the fourth two-position two-way solenoid valve 15 are activated.

[0046] When hydraulic cylinder 8 retracts: electric motor 4 drives hydraulic pump 3 to supply oil to the rod chamber. If Zyr > Z, the first two-position two-way solenoid valve 9 is activated. If Zyr ≤ Z, the first two-position two-way solenoid valve 9 and the second two-position two-way solenoid valve 10 are activated. Here, Zyr is the pressure in the rodless chamber of hydraulic cylinder 8, and Z is the pressure in hydraulic accumulator 16.

[0047] Specifically, the excavator high-frequency response energy recovery system based on accumulator-assisted oil replenishment includes a hydraulic oil tank 1, a hydraulic pump 3, an electric motor 4, a three-position four-way solenoid valve 7, a hydraulic cylinder 8, a first two-position two-way solenoid valve 9, a second two-position two-way solenoid valve 10, a third two-position two-way solenoid valve, a fourth two-position two-way solenoid valve, and a hydraulic accumulator 16. The extension and retraction of the hydraulic cylinder 8 is used to drive the movement of the excavator bucket.

[0048] The three-position four-way solenoid valve 7 includes an oil inlet P, an oil outlet A, an oil outlet B, and an oil return port T.

[0049] The output shaft of the electric motor 4 is driven by the hydraulic pump 3 to drive the hydraulic pump 3. The oil inlet of the hydraulic pump 3 is connected to the hydraulic oil tank 1. The oil outlet of the hydraulic pump 3 is connected to the oil inlet P of the three-position four-way solenoid valve 7.

[0050] The outlet A of the three-position four-way solenoid valve 7 is connected to the rodless chamber of the hydraulic cylinder 8. The outlet B of the three-position four-way solenoid valve 7 is connected to the rod chamber of the hydraulic cylinder 8. The return port T of the three-position four-way solenoid valve 7 is connected to the inlet of the first two-position two-way solenoid valve 9. The outlet of the first two-position two-way solenoid valve 9 is connected to the hydraulic port of the hydraulic accumulator 16 and the inlet of the second two-position two-way solenoid valve 10. The outlet of the second two-position two-way solenoid valve 10 is connected to the hydraulic oil tank 1.

[0051] The hydraulic port of the hydraulic accumulator 16 is connected to the inlet of the third two-position two-way solenoid valve 13 and the fourth two-position two-way solenoid valve 15. The outlet of the third two-position two-way solenoid valve 13 is connected to the outlet of the hydraulic pump 3. The outlet of the fourth two-position two-way solenoid valve 15 is connected to the inlet of the hydraulic pump 3.

[0052] The first two-position two-way solenoid valve 9, the second two-position two-way solenoid valve 10, the third two-position two-way solenoid valve 13, and the fourth two-position two-way solenoid valve 15 are all structures without exhaust ports.

[0053] The three-position four-way solenoid valve 7 includes an inlet port P, an outlet port A, an outlet port B, and a return port T. When the control terminal a of the three-position four-way solenoid valve 7 is energized, the inlet port P is connected to the outlet port A, and the return port T is connected to the outlet port B. When the control terminal b of the three-position four-way solenoid valve 7 is energized, the inlet port P is connected to the outlet port B, and the return port T is connected to the outlet port A. When the three-position four-way solenoid valve 7 is in the middle position, the ports are not connected to each other.

[0054] In this embodiment, when the third control terminal c of the first two-position two-way solenoid valve 9 is energized, the first two-position two-way solenoid valve 9 is turned on. When the fourth control terminal d of the second two-position two-way solenoid valve 10 is energized, the second two-position two-way solenoid valve 10 is turned on. When the fifth control terminal e of the third two-position two-way solenoid valve 13 is energized, the third two-position two-way solenoid valve 13 is turned on. When the sixth control terminal f of the fourth two-position two-way solenoid valve 15 is energized, the fourth two-position two-way solenoid valve 15 is turned on.

[0055] When the control terminal of the solenoid valve is de-energized, the three-position four-way solenoid valve 7, the first two-position two-way solenoid valve 9, the second two-position two-way solenoid valve 10, the third two-position two-way solenoid valve 13, and the fourth two-position two-way solenoid valve 15 are all in the off state.

[0056] This invention discloses a high-frequency response energy recovery system for excavators based on accumulator-assisted oil replenishment. This system is particularly suitable for high-frequency response, energy-saving, and emission-reducing excavators, especially electro-hydraulic hybrid excavators. The excavator's high-frequency response energy recovery system relies on an electric motor 4 to drive the extension and retraction of a hydraulic cylinder 8, thereby driving the movement of the excavator's bucket. Through the accumulator and control of the oil circuit, this system reduces the excavator's frequency response time, minimizes overflow losses, lowers energy consumption, and significantly improves energy utilization. It effectively solves the problems of high energy consumption and low energy utilization in traditional excavator hydraulic systems.

[0057] During the release process of the hydraulic accumulator 16, the electric motor 4 also works simultaneously, with hydraulic oil supplied by the hydraulic pump 3 and the hydraulic accumulator 16 at the same time, which reduces the frequency response time of the excavator.

[0058] Based on the above embodiments, in an optional embodiment of the present invention, such as Figure 1 As shown, the excavator high-frequency response energy recovery system based on accumulator-assisted oil replenishment also includes a first check valve 2. The inlet of the first check valve 2 is connected to the hydraulic oil tank 1. The outlet of the first check valve 2 is connected to the inlet of the hydraulic pump 3.

[0059] Specifically, the first check valve 2 prevents hydraulic oil from flowing into the hydraulic oil tank 1 when the hydraulic oil from the hydraulic accumulator 16 is supplied to the inlet of the hydraulic pump 3 via the fourth two-position two-way solenoid valve 15. This greatly improves the effect of auxiliary oil replenishment.

[0060] Based on the above embodiments, in an optional embodiment of the present invention, such as Figure 1As shown, the excavator high-frequency response energy recovery system based on accumulator-assisted oil replenishment further includes a second check valve 5 and a first relief valve 6. The inlet of the second check valve 5 is connected to the outlet of the hydraulic pump 3. The outlet of the second check valve 5 is connected to the inlet P of the three-position four-way solenoid valve 7. The inlet pipe of the first relief valve 6 is connected to the outlet of the second check valve 5. The outlet of the first relief valve 6 is connected to the hydraulic oil tank 1.

[0061] Specifically, the first relief valve 6 prevents excessive pressure at the outlet of the hydraulic pump 3, thus avoiding damage to the hydraulic pump 3. The first check valve 2 prevents hydraulic oil from back-flowing and impacting the hydraulic pump 3 when the pressure at the hydraulic cylinder 8 exceeds the pressure at the outlet of the hydraulic pump 3, thus preventing damage to the hydraulic pump 3. This significantly improves the safety and service life of the entire system and has considerable practical significance.

[0062] Based on the above embodiments, in an optional embodiment of the present invention, such as Figure 1 As shown, the excavator high-frequency response energy recovery system based on accumulator-assisted oil replenishment further includes a third check valve 11. The oil inlet of the third check valve 11 is connected to the outlet of the first two-position two-way solenoid valve 9 and the inlet of the second two-position two-way solenoid valve 10. The oil outlet of the third check valve 11 is connected to the inlet of the third two-position two-way solenoid valve 13, the inlet of the fourth two-position two-way solenoid valve 15, and the hydraulic port of the hydraulic accumulator 16.

[0063] Specifically, the third check valve 11 can prevent the hydraulic oil from the hydraulic accumulator 16 from flowing into the hydraulic oil tank 1 through the second two-position two-way solenoid valve 10, thus avoiding energy loss, which has great practical significance.

[0064] Based on the above embodiments, in an optional embodiment of the present invention, such as Figure 1 As shown, the excavator high-frequency response energy recovery system based on accumulator-assisted oil replenishment further includes a fourth check valve 12 and a fifth check valve 14. The inlet of the fourth check valve 12 is connected to the outlet of the third two-position two-way solenoid valve 13. The outlet of the fourth check valve 12 is connected to the inlet P of the third three-position four-way solenoid valve 7. The inlet of the fifth check valve 14 is connected to the outlet of the fourth two-position two-way solenoid valve 15. The outlet of the fifth check valve 14 is connected to the inlet of the hydraulic pump 3.

[0065] Specifically, the fourth check valve 12 and the fifth check valve 14 can effectively prevent hydraulic oil from flowing to the hydraulic accumulator 16 during the extension of the hydraulic cylinder 8, thus avoiding the problem that the hydraulic cylinder 8 cannot extend or extends too slowly, which has great practical significance.

[0066] Based on the above embodiments, in an optional embodiment of the present invention, such as Figure 1 As shown, the excavator high-frequency response energy recovery system based on accumulator-assisted oil replenishment also includes a second overflow valve 17.

[0067] The inlet of the second relief valve 17 is connected to the hydraulic port of the hydraulic accumulator 16. The outlet of the second relief valve 17 is connected to the hydraulic oil tank 1.

[0068] Specifically, the second relief valve 17 can prevent the hydraulic accumulator 16 from being under excessive pressure, thus ensuring the stable operation of the entire hydraulic system.

[0069] The steps for extending the hydraulic cylinder 8 of the excavator high-frequency response energy recovery system based on accumulator-assisted oil replenishment of the present invention include A1 to A4.

[0070] A1. Determine whether the start-up time of hydraulic pump 3 exceeds the first preset time.

[0071] A2. When it is determined that the start time of hydraulic pump 3 has not exceeded the first preset time, the first two-position two-way solenoid valve 9 and the third two-position two-way solenoid valve 13 are opened so that the hydraulic oil of hydraulic accumulator 16 is sent to the rodless chamber of hydraulic cylinder 8 through the third two-position two-way solenoid valve 13, and the return oil of the rod chamber of hydraulic cylinder 8 is sent to the third two-position two-way solenoid valve 13 through the three-position four-way solenoid valve 7 and the first two-position two-way solenoid valve 9, thereby reducing the frequency response time of the hydraulic system.

[0072] A3. When it is determined that the start time of hydraulic pump 3 exceeds the first preset time, the first two-position two-way solenoid valve 9, the second two-position two-way solenoid valve 10 and the fourth two-position two-way solenoid valve 15 are turned on so that the hydraulic oil of hydraulic accumulator 16 is sent to the oil inlet of hydraulic pump 3 through the fourth two-position two-way solenoid valve 15 to achieve auxiliary oil replenishment.

[0073] A4. The electric motor 4 drives the hydraulic pump 3 to deliver oil, and energizes the control terminal a of the three-position four-way solenoid valve 7. The inlet port P and outlet port A are connected, and the outlet port B and return port T are connected. This allows the hydraulic pump 3 to deliver oil to the rodless chamber of the hydraulic cylinder 8 and to return oil to the rod chamber of the hydraulic cylinder 8.

[0074] Preferably, when the hydraulic cylinder 8 of the energy recovery system extends, step A5 is also included. A5: After the hydraulic cylinder 8 has extended to its full position, all solenoid valves are closed.

[0075] Specifically, in the extension oil circuit of the hydraulic cylinder 8 in the energy recovery system, the electric motor 4 and the hydraulic pump 3 are arranged coaxially. The oil outlet of the hydraulic oil tank 1 is connected to the oil inlet of the first check valve 2. The oil outlet of the first check valve 2 is connected to the oil inlet of the hydraulic pump 3. The oil outlet of the hydraulic pump 3 is connected to the oil inlet of the second check valve 5. The oil outlet of the second check valve 5 is connected to the oil inlet P of the three-position four-way solenoid valve 7.

[0076] The outlet A of the three-position four-way solenoid valve 7 is connected to the rodless chamber of the hydraulic cylinder 8. The rod chamber of the hydraulic cylinder 8 is connected to the outlet B of the three-position four-way solenoid valve 7. The return port T of the three-position four-way solenoid valve 7 is connected to the inlet of the first and second-position two-way solenoid valve 9.

[0077] The outlet of the first two-position two-way solenoid valve 9 is connected to the inlet of the second two-position two-way solenoid valve 10 and the oil inlet of the second check valve 5. The outlet of the second two-position two-way solenoid valve 10 is connected to the return port of the hydraulic oil tank 1.

[0078] The inlet of the first relief valve 6 is connected to the first bypass port, which is a pipe leading from the outlet of the first one-way valve 2 and the inlet P of the three-position four-way solenoid valve 7. The outlet of the first relief valve 6 is connected to the return port of the hydraulic oil tank 1.

[0079] In the high-frequency response oil circuit for energy release from the hydraulic accumulator 16, the inlet of the third check valve 11 is connected to the outlet of the first two-position two-way solenoid valve 9 and the inlet of the second two-position two-way solenoid valve 10. The outlet of the third check valve 11 is connected to the inlet of the third two-position two-way solenoid valve 13, the inlet of the fourth two-position two-way solenoid valve 15, and the hydraulic port of the hydraulic accumulator 16.

[0080] The inlet of the fourth check valve 12 is connected to the outlet of the third two-position two-way solenoid valve 13. The outlet of the fourth check valve 12 is connected to the second bypass interface led out from the pipeline between the outlet of the first check valve 2 and the inlet P of the three-position four-way solenoid valve 7.

[0081] The inlet of the fifth check valve 14 is connected to the outlet of the fourth two-position two-way solenoid valve 15. The outlet of the fifth check valve 14 is connected to the third bypass interface led out from the pipeline between the outlet of the hydraulic oil tank 1 and the inlet of the hydraulic pump 3.

[0082] The steps for retracting the hydraulic cylinder 8 of the excavator high-frequency response energy recovery system based on accumulator-assisted oil replenishment of the present invention include B1 to B4.

[0083] B1. The electric motor 4 drives the hydraulic pump 3 to deliver oil, and energizes the control terminal b of the three-position four-way solenoid valve 7. The oil inlet P and the oil outlet B are connected, and the oil outlet A and the oil return T are connected. This allows the hydraulic pump 3 to deliver oil to the rod chamber of the hydraulic cylinder 8 and to return oil to the rodless chamber of the hydraulic cylinder 8.

[0084] B2. Compare the pressure Zyr in the rodless chamber of hydraulic cylinder 8 with the pressure Z in hydraulic accumulator 16.

[0085] B3. When it is determined that Zyr > Z, the first two-position two-way solenoid valve 9 is turned on so that the hydraulic oil in the rodless chamber of the hydraulic cylinder 8 can flow to the hydraulic accumulator 16 for energy storage through the first two-position two-way solenoid valve 9 and the third one-way valve 11.

[0086] Specifically: When Zyr > Z, it is determined whether the pressure Z of the hydraulic accumulator 16 is less than the pressure threshold. If so, the first two-position two-way solenoid valve 9 is activated so that the hydraulic oil in the rodless chamber of the hydraulic cylinder 8 can flow to the hydraulic accumulator 16 for energy storage through the first two-position two-way solenoid valve 9 and the third one-way valve 11.

[0087] B4. When it is determined that Zyr≤Z, or when it is determined that Z≥pressure threshold, the first two-position two-way solenoid valve 9 and the second two-position two-way solenoid valve 10 are turned on so that the hydraulic oil in the rodless chamber of the hydraulic cylinder 8 flows to the hydraulic oil tank 1 through the first two-position two-way solenoid valve 9 and the second two-position two-way solenoid valve 10.

[0088] Preferably, the retraction of the hydraulic cylinder 8 in the energy recovery system further includes step B5. B5: After the hydraulic cylinder 8 retracts into position, all solenoid valves are closed.

[0089] Specifically, in the energy recovery oil circuit of the retracting hydraulic cylinder 8, the hydraulic port of the hydraulic accumulator 16 is connected to the inlet of the second relief valve 17. The outlet of the second relief valve 17 is connected to the return port of the hydraulic oil tank 1.

[0090] The working principle of hydraulic cylinder 8 when it extends is as follows:

[0091] When the hydraulic pump 3 has been running for less than the first preset time, the hydraulic oil in the hydraulic accumulator 16 is released into the rodless chamber inlet of the hydraulic cylinder 8. This allows the energy recovered by the hydraulic accumulator 16 to directly drive the hydraulic cylinder 8 to extend, achieving energy conservation. Simultaneously, the hydraulic pump 3 operates synchronously, supplying hydraulic oil to the system and achieving high-frequency response.

[0092] When the hydraulic pump 3 runs for longer than the first preset time, the hydraulic oil in the hydraulic accumulator 16 is released into the oil inlet of the hydraulic pump 3. In this way, the energy recovered by the hydraulic accumulator 16 can provide auxiliary oil replenishment for the hydraulic pump 3. The operation of the hydraulic pump 3 causes the hydraulic oil to flow into the rodless chamber inlet of the hydraulic cylinder 8, thereby extending the hydraulic cylinder 8.

[0093] The working principle of hydraulic cylinder 8 when it retracts is as follows:

[0094] Hydraulic oil discharged from the rodless chamber of hydraulic cylinder 8 passes through the three-position four-way solenoid valve 7, the first and second-position two-way solenoid valves 9, and the third check valve 11, and is stored in the hydraulic accumulator 16. In this way, the hydraulic energy of the hydraulic system is stored in the hydraulic accumulator 16. At this time, hydraulic pump 3 also operates, causing hydraulic oil from hydraulic pump 3 to flow into the rod chamber of hydraulic cylinder 8, thus retracting hydraulic cylinder 8.

[0095] Specifically, when the hydraulic cylinder 8 extends: the electric motor 4 drives the hydraulic pump 3 to supply hydraulic oil from the hydraulic oil tank 1 to the entire oil circuit. The hydraulic oil passes through the first check valve 2, the hydraulic pump 3, the second check valve 5, and the three-position four-way solenoid valve 7, and enters the rodless chamber of the hydraulic cylinder 8 to extend the hydraulic cylinder 8.

[0096] Meanwhile, when the hydraulic pump 3 has been running for less than the first preset time, the outlet of the hydraulic pump 3 must be re-pressurized. During this process, leakage of the hydraulic pump 3 and the compressibility of the oil itself cause a dead zone in the output flow of the hydraulic pump 3 relative to its input speed. The hydraulic oil in the hydraulic accumulator 16 is released to the rodless chamber inlet of the hydraulic cylinder 8 through the third two-position two-way solenoid valve 13, the fourth one-way valve 12, and the three-position four-way solenoid valve 7. In this way, the energy recovered by the hydraulic accumulator 16 can directly drive the hydraulic cylinder 8 to extend, realizing the high-frequency response of the excavator.

[0097] When the hydraulic pump 3 starts running for longer than the first preset time, the hydraulic pump 3 often experiences "air suction" during high-speed operation, resulting in negative pressure or cavitation at the intake of the hydraulic pump 3. In severe cases, air may be sucked into the system, causing hydraulic oil atomization, system performance degradation, or even equipment damage. The hydraulic oil in the hydraulic accumulator 16 is released to the oil inlet of the hydraulic pump 3, so the energy recovered by the hydraulic accumulator 16 can provide auxiliary oil replenishment for the hydraulic pump 3.

[0098] When the hydraulic cylinder 8 retracts, the system performs energy recovery. At this time, the hydraulic oil in the rodless chamber of the hydraulic cylinder 8 passes through the three-position four-way solenoid valve 7, the first and second-position two-way solenoid valves 9 and the third check valve 11, and enters the hydraulic accumulator 16 to realize energy recovery.

[0099] When hydraulic cylinder 8 extends, the system releases energy. At this time: if the hydraulic oil in hydraulic accumulator 16 has not exceeded the first preset time since the hydraulic pump 3 started running, it flows through the third two-position two-way solenoid valve 13 and the fourth check valve 12, through the second bypass, and then through the three-position four-way solenoid valve 7 into the rodless chamber of hydraulic cylinder 8 to extend again. If the hydraulic oil in hydraulic accumulator 16 has exceeded the first preset time since the hydraulic pump 3 started running, it enters hydraulic pump 3 through the fourth two-position two-way solenoid valve 15 and the fifth check valve 14. This achieves energy reuse.

[0100] This invention's excavator high-frequency response energy recovery system, based on accumulator-assisted oil replenishment, utilizes a hydraulic accumulator 16 to reduce frequency response time and improve energy recovery. Building upon the hydraulic drive system jointly implemented by the electric motor 4 and hydraulic pump 3, this system achieves a hydraulic drive and energy recovery, further enhancing the excavator's hydraulic system's energy recovery capability and achieving high-frequency response. A two-position two-way solenoid valve separates the energy recovery oil circuits under different oil pressures, reducing oil energy loss and improving energy utilization.

[0101] Example 2: This application also provides an excavator. The excavator includes a high-frequency response energy recovery system based on accumulator-assisted fuel replenishment, as described in any paragraph of Example 1.

[0102] Obviously, the above detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to describe preferred embodiments, not all embodiments, and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Based on the embodiments of the invention, any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art to all other embodiments obtained without inventive effort are within the scope of protection of the invention.

Claims

1. An excavator energy recovery system based on accumulator-assisted fuel replenishment, characterized in that, The device includes a hydraulic cylinder, a three-position four-way solenoid valve, a hydraulic pump, an electric motor connected to the hydraulic pump, a first two-position two-way solenoid valve connected to the return port T of the three-position four-way solenoid valve, a second two-position two-way solenoid valve connected between the first two-position two-way solenoid valve and the hydraulic oil tank, a hydraulic accumulator connected to the first two-position two-way solenoid valve, a third two-position two-way solenoid valve connected to the hydraulic accumulator, and a fourth two-position two-way solenoid valve; wherein, the inlet pipe of the hydraulic pump is connected to the hydraulic oil tank and the fourth two-position two-way solenoid valve; the outlet ports A and B of the three-position four-way solenoid valve are respectively connected to the rod chamber and rodless chamber of the hydraulic cylinder, and the inlet port P is connected to the outlet port of the hydraulic pump and the third two-position two-way solenoid valve; When the hydraulic cylinder extends: the electric motor drives the hydraulic pump to supply oil to the rodless chamber; if the hydraulic pump's start time does not exceed the first preset time, the first and third two-position two-way solenoid valves are activated, so that the hydraulic oil from the hydraulic accumulator is supplied to the rodless chamber of the hydraulic cylinder through the third two-position two-way solenoid valve, and the return oil from the rod chamber of the hydraulic cylinder passes through the three-position four-way solenoid valve and the first and second two-way solenoid valves, and enters the third two-way solenoid valve, reducing the frequency response time of the hydraulic system; if the hydraulic pump's start time exceeds the first preset time, the first, second, and fourth two-position two-way solenoid valves are activated, so that the hydraulic oil from the hydraulic accumulator is supplied to the hydraulic pump's inlet through the fourth two-way solenoid valve, achieving auxiliary oil replenishment; When the hydraulic cylinder retracts: the electric motor drives the hydraulic pump to supply oil to the rod chamber; if Zyr > Z, the first and second position two-way solenoid valves are activated so that the hydraulic oil in the rodless chamber of the hydraulic cylinder can flow to the hydraulic accumulator for energy storage through the first and second position two-way solenoid valves and the third check valve; if Zyr ≤ Z, the first and second position two-way solenoid valves are activated so that the hydraulic oil in the rodless chamber of the hydraulic cylinder can flow to the hydraulic oil tank through the first and second position two-way solenoid valves; where Zyr is the pressure in the rodless chamber of the hydraulic cylinder; and Z is the pressure in the hydraulic accumulator.

2. The excavator energy recovery system based on accumulator-assisted fuel replenishment according to claim 1, characterized in that, The three-position four-way solenoid valve includes an inlet port P, an outlet port A, an outlet port B, and a return port T; The three-position four-way solenoid valve is constructed as follows: when the control terminal a is energized, the oil inlet P is connected to the oil outlet A, and the oil return port T is connected to the oil outlet B; when the control terminal b is energized, the oil inlet P is connected to the oil outlet B, and the oil return port T is connected to the oil outlet A; when the three-position four-way solenoid valve is in the middle position, the oil ports are not connected to each other. The output shaft of the electric motor is connected to the hydraulic pump to drive the hydraulic pump to work; The return port T of the three-position four-way solenoid valve is connected to the inlet of the first two-position two-way solenoid valve; the outlet of the first two-position two-way solenoid valve is connected to the hydraulic port of the hydraulic accumulator and the inlet of the second two-position two-way solenoid valve; the outlet of the second two-position two-way solenoid valve is connected to the hydraulic oil tank. The hydraulic port of the hydraulic accumulator is connected to the inlet of the third two-position two-way solenoid valve and the fourth two-position two-way solenoid valve; the outlet of the third two-position two-way solenoid valve is connected to the outlet of the hydraulic pump; and the outlet of the fourth two-position two-way solenoid valve is connected to the inlet of the hydraulic pump.

3. The excavator energy recovery system based on accumulator-assisted refueling according to any one of claims 1 to 2, characterized in that, It also includes a first check valve and a second check valve; The inlet of the first check valve is connected to the hydraulic oil tank; the outlet of the first check valve is connected to the inlet of the hydraulic pump. The inlet of the second check valve is connected to the outlet of the hydraulic pump; the outlet of the second check valve is connected to the inlet P of the three-position four-way solenoid valve.

4. The excavator energy recovery system based on accumulator-assisted refueling according to claim 3, characterized in that, It also includes a first relief valve and a second relief valve; The inlet pipe of the first relief valve is connected to the outlet of the second check valve; the outlet of the first relief valve is connected to the hydraulic oil tank. The inlet of the second relief valve is connected to the hydraulic port of the hydraulic accumulator; the outlet of the second relief valve is connected to the hydraulic oil tank.

5. The excavator energy recovery system based on accumulator-assisted refueling according to any one of claims 1 to 2, characterized in that, It also includes a third check valve; the oil inlet of the third check valve is connected to the outlet of the first two-position two-way solenoid valve and the inlet of the second two-position two-way solenoid valve; the oil outlet of the third check valve is connected to the inlet of the third two-position two-way solenoid valve, the inlet of the fourth two-position two-way solenoid valve, and the hydraulic port of the hydraulic accumulator.

6. The excavator energy recovery system based on accumulator-assisted refueling according to any one of claims 1 to 2, characterized in that, It also includes a fourth check valve and a fifth check valve; The inlet of the fourth check valve is connected to the outlet of the third two-position two-way solenoid valve; the outlet of the fourth check valve is connected to the inlet P of the third three-position four-way solenoid valve. The inlet of the fifth check valve is connected to the outlet of the fourth two-position two-way solenoid valve; the outlet of the fifth check valve is connected to the inlet of the hydraulic pump.

7. The excavator energy recovery system based on accumulator-assisted refueling according to any one of claims 1 to 2, characterized in that, The first two-position two-way solenoid valve, the second two-position two-way solenoid valve, the third two-position two-way solenoid valve, and the fourth two-position two-way solenoid valve are all structures without exhaust ports; The steps for extending the hydraulic cylinder include: closing all solenoid valves after the hydraulic cylinder has extended to its full position; The steps for retracting the hydraulic cylinder include: after the hydraulic cylinder has retracted to its position, close all solenoid valves.

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