An excavator, a three-cylinder based fast start and energy recovery system

Abstract

A rapid start and energy recovery system for an excavator based on a three-chamber cylinder is disclosed, relating to the field of excavator technology. The system includes a first hydraulic accumulator, a second hydraulic accumulator, a four-position four-way solenoid valve with a first inlet, a first working outlet, a second working outlet, and a first outlet, a hydraulic pump connected between the first inlet and a hydraulic tank, a motor driven by the hydraulic pump, a second two-position three-way solenoid valve capable of switching the first return port to either the second hydraulic accumulator or the hydraulic tank, a two-position two-way solenoid valve connected between the second hydraulic accumulator and the outlet of the hydraulic pump, a three-chamber cylinder with chambers A1 and A3 for extending the hydraulic rod and chamber A2 for retracting the hydraulic rod, and a first two-position three-way solenoid valve capable of switching chamber A3 to either the hydraulic tank or the first hydraulic accumulator. The first working outlet is connected to chamber A2. The second working outlet is connected to chamber A1.

Description

Technical Field

[0001] This invention relates to the field of excavator technology, and more specifically, to an excavator and a rapid start-up and energy recovery system based on a three-cylinder engine. Background Technology

[0002] In the construction machinery industry, excavators, as core equipment, directly impact project progress and operating costs through their operational performance and energy efficiency. Currently, excavators commonly suffer from insufficient boom system response speed when dealing with complex working conditions involving heavy loads and frequent start-stop cycles. Traditional hydraulic drive systems require a considerable amount of time to build sufficient pressure to drive the cylinders during the startup phase, resulting in sluggish initial movements that fail to meet the real-world demands for rapid response in high-efficiency operations.

[0003] Furthermore, during typical cyclical operations, excavators generate a significant amount of recoverable potential and kinetic energy when the boom is lowered or the mechanism is braked. However, in conventional systems, this energy is usually dissipated as heat through throttling or overflow, resulting in significant energy waste. This low energy efficiency directly increases the equipment's fuel or electricity consumption, raising operating costs for users.

[0004] Traditional technical solutions have limitations in improving response speed and energy recovery efficiency, often resulting in one aspect being sacrificed for the other. Slow response speed restricts operational efficiency, while significant energy waste exacerbates operating costs and environmental burden. This has become a key common problem hindering the technological upgrading of excavators and the green development of the industry. Summary of the Invention

[0005] The present invention provides an excavator and a three-cylinder-based rapid start and energy recovery system, which aims to improve at least one of the above-mentioned technical problems.

[0006] To address the aforementioned technical problems, this invention provides a rapid start-up and energy recovery system based on a three-chamber cylinder. The system includes a first hydraulic accumulator, a second hydraulic accumulator, a four-position four-way solenoid valve with a first inlet, a first working outlet, a second working outlet, and a first outlet, a hydraulic pump connected between the first inlet and a hydraulic tank, a motor connected to the hydraulic pump, a second two-position three-way solenoid valve capable of switching the first return port to either the second hydraulic accumulator or the hydraulic tank, a two-position two-way solenoid valve connected between the second hydraulic accumulator and the hydraulic pump outlet, a three-chamber cylinder with chambers A1 and A3 for extending the hydraulic rod and chamber A2 for retracting the hydraulic rod, and a first two-position three-way solenoid valve capable of switching chamber A3 to either the hydraulic tank or the first hydraulic accumulator. The first working outlet is connected to chamber A2. The second working outlet is connected to chamber A1.

[0007] The four-position four-way solenoid directional valve has four connection states. State 1: The first oil inlet is connected to the second working outlet, and the first oil outlet is connected to the first working outlet. State 2: All four ports are disconnected. State 3: The first oil inlet is connected to the first working outlet and the second working outlet, and the first oil outlet is disconnected. State 4: The first oil inlet is connected to the first working outlet, and the first oil outlet is connected to the second working outlet.

[0008] The cross-sectional area of ​​cavity A2 is smaller than that of cavity A1.

[0009] When the three-chamber cylinder is in rapid start-up mode, the four-position four-way solenoid switches to state three, enabling the hydraulic pump to connect simultaneously with chambers A1 and A2, thereby forming a differential connection that allows the hydraulic rod to extend faster.

[0010] Define p1 as the pressure in cavity A2. Define p2 as the pressure in cavity A3.

[0011] As a further optimization, during the rapid start-up condition when the hydraulic rod extends from the three-chamber cylinder under no-load conditions:

[0012] If p1≤first preset value and p2≤second preset value, then the first two-position three-way solenoid directional valve is connected to the first hydraulic accumulator and the A3 chamber of the three-chamber cylinder for auxiliary oil replenishment.

[0013] The four-position four-way solenoid switches to state three, enabling the hydraulic pump to connect simultaneously to chambers A1 and A2, thereby forming a differential connection that allows the hydraulic rod to extend faster.

[0014] If p1 < the pressure of the second hydraulic accumulator, then connect the two-position two-way solenoid directional valve to connect the second hydraulic accumulator to the outlet of the hydraulic pump for auxiliary oil replenishment.

[0015] As a further optimization, when the three-chamber cylinder is in the hydraulic rod extension condition:

[0016] If p1 ≤ the third preset value and the pressure of the first hydraulic accumulator > the fourth preset value, then the first two-position three-way solenoid directional valve is connected to the first hydraulic accumulator and the A3 chamber of the three-chamber cylinder for auxiliary oil replenishment.

[0017] Connect the first and second position three-way solenoid directional valves to the first oil outlet and the hydraulic oil tank.

[0018] The four-position four-way solenoid switches to state one, connecting the hydraulic pump's outlet to chamber A1 of the three-chamber cylinder, and connecting chamber A2 to the first outlet.

[0019] Connect the two-position two-way solenoid directional valve to connect the second hydraulic accumulator to the outlet of the hydraulic pump for auxiliary oil replenishment.

[0020] As a further optimization, when the three-chamber cylinder is in the hydraulic rod retracted state:

[0021] If the pressure of the first hydraulic accumulator is less than or equal to the sixth preset value, it is determined that energy recovery can be performed, and the first two-position three-way solenoid directional valve is connected to the first hydraulic accumulator and the A3 chamber of the three-chamber cylinder for oil storage.

[0022] If the pressure of the second hydraulic accumulator is less than or equal to the sixth preset value, energy recovery is deemed possible, and the second two-position three-way solenoid directional valve is connected to chamber A1 and the second hydraulic accumulator for oil storage. Otherwise, the second two-position three-way solenoid directional valve is connected to chamber A1 and the hydraulic oil tank.

[0023] The four-position four-way solenoid switches to state four, connecting the hydraulic pump's oil outlet to chamber A2 and chamber A1 to the first oil outlet.

[0024] As a further optimization, the third preset value is less than the fourth preset value.

[0025] As a further optimization, the sixth preset value is less than the fifth preset value.

[0026] As a further optimization, the first preset value < the fifth preset value < the third preset value. The second preset value < the fourth preset value.

[0027] As a further optimization, the four-position four-way solenoid valve is configured such that all four ports are disconnected when the power is off and the valve is in the closed state.

[0028] As a further optimization, the two-position two-way solenoid directional valve is configured to be in the open state when the power is off and it is in the closed state.

[0029] As a further optimization, the first two-position three-way solenoid directional valve is configured such that when it is in the closed state (power off), chamber A3 is connected to the hydraulic oil tank, and when it is in the open state (powered on), chamber A3 is connected to the first hydraulic accumulator.

[0030] The second two-position three-way solenoid directional valve is configured such that when it is in the closed state (de-energized), the first return port is connected to the second hydraulic accumulator, and when it is in the open state (energized), the first return port is connected to the hydraulic oil tank.

[0031] As a further optimization, a rapid start-up and energy recovery system based on a three-cylinder also includes a first relief valve, a second relief valve, and a third relief valve.

[0032] The inlet of the first relief valve is connected to the outlet of the hydraulic pump. The outlet of the first relief valve is connected to the hydraulic oil tank.

[0033] The inlet of the second relief valve is connected to the outlet of the first hydraulic accumulator. The outlet of the relief valve is connected to the hydraulic oil tank.

[0034] The inlet of the third relief valve is connected to the outlet of the second hydraulic accumulator. The outlet of the third relief valve is connected to the hydraulic oil tank.

[0035] This application also provides an excavator that includes a three-cylinder-based rapid start and energy recovery system as described in any paragraph of the first aspect.

[0036] By adopting the above technical solution, the present invention can achieve the following technical effects:

[0037] This invention, by employing an asymmetrical three-chamber cylinder and combining it with differential connection technology, enables rapid piston extension under relatively low flow conditions, significantly improving the system's response speed and meeting the rapid start-up requirements of excavators and other construction machinery under complex working conditions.

[0038] Meanwhile, the system incorporates dual hydraulic accumulators, which can selectively perform auxiliary oil replenishment or energy recovery based on pressure judgment under different working conditions. This effectively superimposes flow and enhances thrust during rapid start-up and piston extension, thereby enabling heavy-duty operation without relying on high-power pumps, reducing system costs and energy consumption.

[0039] During piston retraction, the system can convert hydraulic energy under load into pressure energy in the accumulator for recovery and release for reuse when needed, avoiding throttling and overflow losses common in traditional hydraulic systems and significantly improving energy utilization efficiency.

[0040] Furthermore, this invention achieves precise switching of different oil circuits under conditions such as rapid start-up, extension, retraction, and energy recovery through the coordinated control of a four-position four-way solenoid directional valve, a two-position three-way solenoid directional valve, and a two-position two-way solenoid directional valve. Combined with an overflow valve to provide overpressure protection for the accumulator, it ensures the safety and stability of the system operation. Overall, it effectively solves the problems of slow response speed, high energy consumption, and low energy utilization rate of traditional excavator booms. Attached Figure Description

[0041] 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.

[0042] Figure 1 This is a schematic diagram of a rapid start-up and energy recovery system based on a three-cylinder engine.

[0043] The following are labels in the diagram: 1-Hydraulic pump, 2-Motor, 3-First relief valve, 4-Four-position four-way solenoid directional valve, 5-Three-chamber cylinder, 6-First two-position three-way solenoid directional valve, 7-First hydraulic accumulator, 8-Second relief valve, 9-Second two-position three-way solenoid directional valve, 10-Second hydraulic accumulator, 11-Two-position two-way solenoid directional valve, 12-Third relief valve, 13-Hydraulic oil tank. Detailed Implementation

[0044] 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.

[0045] Example 1, by Figure 1 As shown, this embodiment of the invention provides a rapid start-up and energy recovery system based on a three-chamber cylinder 5, comprising a first hydraulic accumulator 7, a second hydraulic accumulator 10, a four-position four-way solenoid valve 4 with a first oil inlet, a first working outlet, a second working outlet, and a first oil outlet, a hydraulic pump 1 connected between the first oil inlet and a hydraulic oil tank 13, a motor 2 connected to the hydraulic pump 1, a second two-position three-way solenoid valve 9 capable of switching the first oil return port to either the second hydraulic accumulator 10 or the hydraulic oil tank 13, a two-position two-way solenoid valve 11 connected between the second hydraulic accumulator 10 and the oil outlet of the hydraulic pump 1, a three-chamber cylinder 5 with chambers A1 and A3 for extending the hydraulic rod and chamber A2 for retracting the hydraulic rod, and a first two-position three-way solenoid valve 6 capable of switching the A3 chamber to either the hydraulic oil tank 13 or the first hydraulic accumulator 7. The first working outlet is connected to chamber A2. The second working outlet is connected to chamber A1.

[0046] The four-position four-way solenoid directional valve 4 is configured with four connection states. State 1: The first oil inlet is connected to the second working outlet, and the first oil outlet is connected to the first working outlet. State 2: All four ports are disconnected. State 3: The first oil inlet is connected to the first working outlet and the second working outlet, and the first oil outlet is disconnected. State 4: The first oil inlet is connected to the first working outlet, and the first oil outlet is connected to the second working outlet.

[0047] Preferred, such as Figure 1 As shown, the four-position four-way solenoid valve 4 is configured such that all four ports are disconnected when it is in the closed state after power failure.

[0048] Preferred, such as Figure 1 As shown, the two-position two-way solenoid valve 11 is configured to be in the open state when it is in the closed state due to power failure.

[0049] Preferred, such as Figure 1As shown, the first two-position three-way solenoid directional valve 6 is configured such that when it is in the closed state (de-energized), chamber A3 is connected to the hydraulic oil tank 13, and when it is in the open state (energized), chamber A3 is connected to the first hydraulic accumulator 7.

[0050] Preferred, such as Figure 1 As shown, the second two-position three-way solenoid directional valve 9 is configured such that when it is in the closed state (de-energized), the first return port is connected to the second hydraulic accumulator 10, and when it is in the open state (energized), the first return port is connected to the hydraulic oil tank 13.

[0051] Preferred, such as Figure 1 As shown, the rapid start-up and energy recovery system based on the three-chamber cylinder 5 also includes a first overflow valve 3, a second overflow valve 8, and a third overflow valve 12.

[0052] The inlet of the first relief valve 3 is connected to the outlet of the hydraulic pump 1. The outlet of the first relief valve 3 is connected to the hydraulic oil tank 13.

[0053] The inlet of the second relief valve 8 is connected to the outlet of the first hydraulic accumulator 7. The outlet of the relief valve is connected to the hydraulic oil tank 13.

[0054] The inlet of the third relief valve 12 is connected to the outlet of the second hydraulic accumulator 10. The outlet of the third relief valve 12 is connected to the hydraulic oil tank 13.

[0055] Specifically, the second relief valve 8 and the third relief valve 12 can prevent the pressure of the first hydraulic accumulator 7 and the second hydraulic accumulator 10 from becoming too high.

[0056] This invention discloses a rapid start-up and energy recovery system based on a three-chamber cylinder 5. The system employs an asymmetric differential connection of the three-chamber cylinder 5, improving response speed and achieving rapid start-up. The use of a first hydraulic accumulator 7 and a second hydraulic accumulator 10 avoids throttling and overflow losses, significantly improving energy utilization. This effectively solves the problems of slow response speed, high energy consumption during extension and retraction, and low energy utilization in traditional excavator booms.

[0057] The rapid start and energy recovery system based on the three-chamber cylinder 5 can be divided into a rapid start oil circuit, a piston extension motion oil circuit, a piston retraction motion oil circuit, and a system energy recovery oil circuit:

[0058] The rapid start hydraulic circuit includes: a hydraulic pump 1, a four-position four-way solenoid directional valve 4, a three-chamber cylinder 5, a first two-position three-way solenoid directional valve 6, a second two-position three-way solenoid directional valve 9, a first hydraulic accumulator 7, a second hydraulic accumulator 10, and a hydraulic oil tank 13. The first inlet of the four-position four-way solenoid directional valve 4 is connected to the outlet of the hydraulic pump 1. The first working outlet of the four-position four-way solenoid directional valve 4 is connected to chamber A2 of the three-chamber cylinder 5. The second working outlet of the four-position four-way solenoid directional valve 4 is connected to chamber A1 of the three-chamber cylinder 5. The working outlet of the first two-position three-way solenoid directional valve 6 is connected to chamber A3 of the three-chamber cylinder 5. The first return port of the four-position four-way solenoid directional valve 4 is connected to the inlet of the second two-position three-way solenoid directional valve 9. The hydraulic cylinder is used to drive the extension and retraction of the boom.

[0059] like Figure 1 As shown, the oil outlet of hydraulic pump 1 is simultaneously connected to chambers A1 and A2 of the three-chamber cylinder 5, forming a differential connection. This allows for faster extension speed with a smaller flow rate, enabling rapid start-up. Simultaneously, when the pressures of the first and second accumulators reach their respective preset values, the first hydraulic accumulator 7 is connected to chamber A3 of the three-chamber cylinder 5 for auxiliary oil replenishment, and the second hydraulic accumulator 10 is connected to the outlet of hydraulic pump 1 for auxiliary oil replenishment. This achieves rapid start-up through differential connection and multi-layered flow superposition of accumulator assistance.

[0060] The piston extension movement hydraulic circuit includes: a hydraulic pump 1, a four-position four-way solenoid directional valve 4, a three-chamber cylinder 5, a first two-position three-way solenoid directional valve 6, a second two-position three-way solenoid directional valve 9, a first hydraulic accumulator 7, a second hydraulic accumulator 10, and a hydraulic oil tank 13. Specifically, the first inlet of the four-position four-way solenoid directional valve 4 is connected to the outlet of the hydraulic pump 1. The second working outlet of the four-position four-way solenoid directional valve 4 is connected to chamber A1 of the three-chamber cylinder 5. The working outlet of the first two-position three-way solenoid directional valve 6 is connected to chamber A3 of the three-chamber cylinder 5. The first return port of the four-position four-way solenoid directional valve 4 is connected to the inlet of the second two-position three-way solenoid directional valve 9. The inlet of the two-position two-way solenoid directional valve 11 is connected to the outlet of the hydraulic pump 1. The outlet of the two-position two-way solenoid directional valve 11 is connected to the second hydraulic accumulator 10.

[0061] Specifically, by detecting the pressure within the first hydraulic accumulator 7 and the second hydraulic accumulator 10, it is determined whether the hydraulic pump 1 can be supplemented with oil to jointly push the piston outward and enhance the extension thrust. That is, the first hydraulic accumulator 7 is connected to chamber A3 of the three-chamber cylinder 5 for auxiliary oil replenishment, and the second hydraulic accumulator 10 is connected to the outlet of the hydraulic pump 1 for auxiliary oil replenishment. This optimizes the problem of oil supply from a single pump, enabling heavy-duty extension without the need for a high-power pump, thus reducing costs.

[0062] The piston retraction hydraulic circuit includes: a hydraulic pump 1, a four-position four-way solenoid directional valve 4, a three-chamber cylinder 5, a first and second-position three-way solenoid directional valve 6, and a hydraulic oil tank 13. Specifically, the first inlet of the four-position four-way solenoid directional valve 4 is connected to the outlet of the hydraulic pump 1. The first working outlet of the four-position four-way solenoid directional valve 4 is connected to chamber A2 of the three-chamber cylinder 5. The second working outlet of the four-position four-way solenoid directional valve 4 is connected to chamber A1 of the three-chamber cylinder 5. The working outlet of the first and second-position three-way solenoid directional valve 6 is connected to chamber A3 of the three-chamber cylinder 5.

[0063] At this time, the first inlet and the first working outlet of the four-position four-way solenoid directional valve 4 are connected, and the first return port and the second working outlet of the four-position four-way solenoid directional valve 4 are connected.

[0064] Based on the above embodiments, the energy recovery during the retraction process can be determined by detecting the pressure of the first hydraulic accumulator 7 and the second hydraulic accumulator 10. Specifically, the energy recovery circuit can convert the hydraulic energy during piston retraction into pressure energy within the hydraulic accumulator, greatly reducing energy loss. Furthermore, the recovered energy can be reused during rapid start-up or piston extension phases to improve energy efficiency.

[0065] The system's energy recovery oil circuit includes: a three-chamber cylinder 5, a first two-position three-way solenoid directional valve 6, a second two-position three-way solenoid directional valve 9, a first hydraulic accumulator 7, a second hydraulic accumulator 10, a four-position four-way solenoid directional valve 4, and a hydraulic oil tank 13. The working outlet of the first two-position three-way solenoid directional valve 6 is connected to chamber A3 of the three-chamber cylinder 5. The inlet of the first two-position three-way solenoid directional valve 6 is connected to the hydraulic port of the first hydraulic accumulator 7. Chamber A2 of the three-chamber cylinder 5 is connected to the first working outlet of the four-position four-way solenoid directional valve 4. The first return port of the four-position four-way solenoid directional valve 4 is connected to the inlet of the second two-position three-way solenoid directional valve 9. The working outlet of the second two-position three-way solenoid directional valve 9 is connected to the hydraulic port of the second hydraulic accumulator 10. The return ports of both the first two-position three-way solenoid directional valve 6 and the second two-position three-way solenoid directional valve 9 are connected to the hydraulic oil tank 13.

[0066] like Figure 1 As shown, the oil outlet of hydraulic pump 1 is simultaneously connected to chambers A1 and A2 of the three-chamber cylinder, forming a differential connection. This allows for faster extension speed with a smaller flow rate, enabling rapid start-up. Simultaneously, when the pressures of the first and second accumulators reach their respective preset values, the first hydraulic accumulator 7 is connected to chamber A3 of the three-chamber cylinder 5 for auxiliary oil replenishment, and the second hydraulic accumulator 10 is connected to the outlet of hydraulic pump 1 for auxiliary oil replenishment. This achieves rapid start-up through differential connection and multi-layered flow superposition of accumulator assistance.

[0067] The aforementioned rapid start and energy recovery system based on a three-chamber cylinder 5 has three operating states: rapid start extension state, piston extension motion state, and piston retraction motion state. Let p1 be the pressure in chamber A2, and p2 be the pressure in chamber A3. The control methods corresponding to these three operating states are as follows.

[0068] When the three-chamber cylinder 5 is in a rapid start-up state, the four-position four-way solenoid switches to state three, simultaneously connecting hydraulic pump 1 to chambers A1 and A2, thus forming a differential connection and allowing the hydraulic rod to extend more quickly. Specifically, when the three-chamber cylinder 5 is in a rapid start-up state with the hydraulic rod extending under no-load conditions:

[0069] If p1≤first preset value and p2≤second preset value, then the first two-position three-way solenoid directional valve 6 is connected to the first hydraulic accumulator 7 and the A3 chamber of the three-chamber cylinder 5 for auxiliary oil replenishment.

[0070] The four-position four-way solenoid switches to state three, enabling hydraulic pump 1 to connect simultaneously to chambers A1 and A2, thereby forming a differential connection that allows the hydraulic rod to extend faster.

[0071] If p1 < the pressure of the second hydraulic accumulator 10, then the two-position two-way solenoid directional valve 11 is connected, so that the second hydraulic accumulator 10 is connected to the outlet of the hydraulic pump 1 for auxiliary oil replenishment.

[0072] In this embodiment, the fast startup includes steps S1 to S4:

[0073] S1. Determine whether p1 exceeds the first preset value.

[0074] S2. When it is determined that p1 does not exceed the first preset value, further determine whether p2 exceeds the second preset value.

[0075] S3. When it is determined that p2 does not exceed the second preset value, the first two-position three-way solenoid directional valve 6 is opened, so that the first hydraulic accumulator 7 is connected to the A3 chamber of the three-chamber cylinder 5 for auxiliary oil replenishment.

[0076] S4. Open the four-position four-way solenoid directional valve 4 (currently in the third position, i.e., state three) to connect the oil outlet of hydraulic pump 1 with chambers A2 and A1 of the three-chamber cylinder 5, thus forming a differential connection. If p1 < the pressure of the second hydraulic accumulator 10, open the two-position two-way solenoid directional valve 11 to connect the second hydraulic accumulator 10 to the outlet of hydraulic pump 1 for auxiliary oil replenishment. Hydraulic pump 1 supplies hydraulic oil from hydraulic oil tank 13 to the oil circuit. The hydraulic oil enters chamber A2 of the three-chamber cylinder 5 through the four-position four-way solenoid directional valve 4 to achieve piston extension.

[0077] Specifically, when chambers A2 and A1 are differentially connected, the internal pressures of the two chambers are equal. However, the cross-sectional area of ​​chamber A2 is smaller than that of chamber A1. Therefore, the thrust of the hydraulic oil acting on the hydraulic rod in chamber A1 is greater than the thrust of the hydraulic oil acting on the hydraulic rod in chamber A2, causing the hydraulic rod to extend outward. Since chambers A2 and A1 are connected, the hydraulic oil flowing out of chamber A1 flows into chamber A2, preventing hydraulic oil loss throughout the system and allowing the hydraulic rod to move rapidly.

[0078] Understandably, since the difference in cross-sectional area between chambers A2 and A1 is fixed, the thrust on the hydraulic rod in the differential connection state is directly proportional to the hydraulic oil pressure. The maximum thrust achievable by the hydraulic cylinder in the differential connection state is less than that in the non-differential connection state where oil is supplied solely to the rodless chamber. However, in the differential connection state, because all the hydraulic oil flowing out of the rod chamber flows into the rodless chamber, the hydraulic rod moves faster.

[0079] Preferably, when the three-chamber cylinder 5 is in the hydraulic rod extension condition:

[0080] If p1 ≤ the third preset value and the pressure of the first hydraulic accumulator 7 > the fourth preset value, then the first two-position three-way solenoid directional valve 6 is connected to the first hydraulic accumulator 7 and the A3 chamber of the three-chamber cylinder 5 for auxiliary oil replenishment.

[0081] Connect the second two-position three-way solenoid directional valve 9 to the first oil outlet and the hydraulic oil tank 13.

[0082] The four-position four-way solenoid switches to state one, connecting the oil outlet of hydraulic pump 1 to chamber A1 of three-chamber cylinder 5, and connecting chamber A2 to the first oil outlet.

[0083] Connect the two-position two-way solenoid directional valve 11 to connect the second hydraulic accumulator 10 to the outlet of the hydraulic pump 1 for auxiliary oil replenishment.

[0084] Specifically, the piston extension movement includes steps B1 to B4:

[0085] B1. Determine whether p1 exceeds the third preset value.

[0086] B2. When it is determined that p1 does not exceed the third preset value, further determine whether the pressure in the first hydraulic accumulator 7 exceeds the fourth preset value.

[0087] B3. When it is determined that the pressure in the first hydraulic accumulator 7 exceeds the fourth preset value, open the two-position three-way solenoid directional valve so that the first hydraulic accumulator 7 is connected to the A3 chamber of the three-chamber cylinder 5 for auxiliary oil replenishment.

[0088] B4. Open the second two-position three-way solenoid directional valve 9 to connect the first oil outlet to the hydraulic oil tank 13. Open the four-position four-way solenoid directional valve 4 (currently in the first working position, i.e., state one) to connect the oil outlet of the hydraulic pump 1 to the A1 chamber of the three-chamber cylinder 5. Open the two-position two-way solenoid directional valve 11 to connect the second hydraulic accumulator 10 to the outlet of the hydraulic pump 1 for auxiliary oil replenishment. The hydraulic pump 1 supplies hydraulic oil from the hydraulic oil tank 13 to the oil circuit. The hydraulic oil enters the A1 chamber of the three-chamber cylinder 5 through the four-position four-way solenoid directional valve 4 to achieve piston extension.

[0089] In this embodiment, during the extension movement: a third preset value is set for p1 to determine whether oil replenishment is needed during extension. If p1 > the third preset value, oil replenishment is not needed; if p1 is less than the third preset value, oil replenishment is needed. A fourth preset value is set for the first hydraulic accumulator 7 to determine whether oil replenishment by the accumulator is needed during extension. If p1 is greater than the first preset value, accumulator-assisted oil replenishment can be performed; if p1 is less than the first preset value, oil replenishment cannot be performed.

[0090] Preferably, when the three-chamber cylinder 5 is in the hydraulic rod retracted state:

[0091] If the pressure of the first hydraulic accumulator 7 is less than or equal to the sixth preset value, it is determined that energy recovery can be performed, and the first two-position three-way solenoid directional valve 6 is connected to the first hydraulic accumulator 7 and the A3 chamber of the three-chamber cylinder 5 for oil storage.

[0092] If the pressure of the second hydraulic accumulator 10 is less than or equal to the sixth preset value, then energy recovery is deemed possible, and the second two-position three-way solenoid valve 9 is connected to chamber A1 and the second hydraulic accumulator 10 for oil storage. Otherwise, the second two-position three-way solenoid valve 9 is connected to chamber A1 and hydraulic oil tank 13.

[0093] The four-position four-way solenoid switches to state four, connecting the oil outlet of hydraulic pump 1 with chamber A2, and connecting chamber A1 with the first oil outlet.

[0094] Specifically, the piston retraction motion includes steps C1 to C4:

[0095] C1. Determine whether p1 exceeds the fifth preset value.

[0096] Specifically, a fifth preset value can be set, or it can be left unset. Setting a fifth preset value can prevent the accumulator from being connected before the pressure of p1 exceeds the sixth preset value, thus preventing a retraction shock.

[0097] C2. When it is determined that p1 exceeds the fifth preset value, further determine whether the pressure in the first hydraulic accumulator 7 exceeds the sixth preset value, and determine whether the pressure in the second hydraulic accumulator 10 exceeds the sixth preset value.

[0098] C3. When it is determined that the pressure in the first hydraulic accumulator 7 does not exceed the sixth preset value, open the first two-position three-way solenoid directional valve 6 so that the first hydraulic accumulator 7 is connected to the A3 chamber of the three-chamber cylinder 5, allowing the hydraulic oil in the A3 chamber of the three-chamber cylinder 5 to enter the first hydraulic accumulator 7 under the action of the cargo load. Otherwise, keep the first two-position three-way solenoid directional valve 6 closed, allowing the hydraulic oil to return directly to the hydraulic oil tank 13.

[0099] C4. When it is determined that the pressure of the second hydraulic accumulator 10 does not exceed the sixth preset value, the second two-position three-way solenoid directional valve 9 remains closed, so that the hydraulic oil in chamber A1 of the three-chamber cylinder 5 enters the second hydraulic accumulator 10 through the second two-position three-way solenoid directional valve 9 under the action of cargo load, thereby realizing the recovery of hydraulic energy. Otherwise, the second two-position three-way solenoid directional valve 9 is opened, so that the hydraulic oil in chamber A1 of the three-chamber cylinder 5 returns directly to the hydraulic oil tank 13 through the second two-position three-way solenoid directional valve 9 under the action of cargo load.

[0100] C5. Open the four-position four-way solenoid directional valve 4 (the working position is the fourth position, i.e., state four) to connect the oil outlet of the hydraulic pump 1 with the A2 chamber of the three-chamber cylinder 5. The hydraulic pump 1 supplies hydraulic oil from the hydraulic oil tank 13 to the oil circuit. The hydraulic oil enters the A2 chamber of the three-chamber cylinder 5 through the four-position four-way solenoid directional valve 4 to realize piston retraction.

[0101] In this embodiment, during the retraction movement, a fifth preset value is set for p1 to determine whether energy can be recovered during retraction. If the value is greater than p1, energy can be recovered; if it is less than p1, energy cannot be recovered. A sixth preset value is set for the first hydraulic accumulator 7 and the second hydraulic accumulator 10 to determine whether energy can be recovered. If the value is greater than p1, energy recovery is not required; if it is less than p1, energy recovery can be performed.

[0102] In this embodiment, two accumulators are provided: a first hydraulic accumulator 7 and a second hydraulic accumulator 10, both of which are set with the same preset value (sixth preset value). During energy recovery, the energy of the return oil pressure is selectively or jointly recovered based on a comparison between the preset value and the accumulator pressure. In other embodiments, the two preset values ​​may be set to different values; this invention does not specifically limit this, and such equivalent technical solutions also fall within the protection scope of this invention.

[0103] Based on the above embodiments, in an optional embodiment of the present invention, the third preset value < the fourth preset value; the sixth preset value < the fifth preset value; the first preset value < the fifth preset value < the third preset value; and the second preset value < the fourth preset value.

[0104] Specifically, to achieve rapid start-up, the preset starting pressure is set to the lowest value. During extension, which is a loaded process, the pressure is higher, hence the third preset value is the highest. During retraction, the fifth preset value falls between the two. Therefore, the first preset value < the fifth preset value < the third preset value. The oil replenishment requirement is low during start-up and high during extension, therefore, the second preset value < the fourth preset value.

[0105] The present invention provides a rapid start-up and energy recovery system based on a three-cylinder 5. On the basis of a hydraulic drive system jointly realized by an electric motor and a hydraulic pump 1, the system improves the start-up speed and significantly optimizes the energy utilization efficiency by using an asymmetrical three-cylinder 5 structure, differential connection technology, and the introduction of a hydraulic accumulator for auxiliary oil replenishment and energy recovery technology.

[0106] In addition, by using four-position four-way, two-position three-way, and two-position two-way solenoid directional valves 11 to separate the oil circuits under different working conditions, different hydraulic accumulators can be selected for auxiliary work or energy recovery based on the matching range of hydraulic oil pressure and preset value, so as to avoid the ineffective loss of oil energy and further improve the energy utilization rate.

[0107] Example 2: This application also provides an excavator that includes a rapid start-up and energy recovery system based on a three-cylinder 5 as described in any paragraph of Example 1.

[0108] 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. A three-cylinder based fast start and energy recovery system, characterized in that, The system includes a first hydraulic accumulator, a second hydraulic accumulator, a four-position four-way solenoid directional valve with a first inlet, a first working outlet, a second working outlet, and a first outlet, a hydraulic pump connected between the first inlet and a hydraulic tank, a motor connected to the hydraulic pump, a second two-position three-way solenoid directional valve capable of switching the first return port to the second hydraulic accumulator or the hydraulic tank, a two-position two-way solenoid directional valve connected between the second hydraulic accumulator and the outlet of the hydraulic pump, a three-chamber cylinder with chambers A1 and A3 for extending the hydraulic rod and chamber A2 for retracting the hydraulic rod, and a first two-position three-way solenoid directional valve capable of switching chamber A3 to the hydraulic tank or the first hydraulic accumulator; wherein the first working outlet is connected to chamber A2; and the second working outlet is connected to chamber A1. The four-position four-way solenoid directional valve has four connection states: State 1: the first oil inlet is connected to the second working outlet, and the first oil outlet is connected to the first working outlet; State 2: all four ports are disconnected; State 3: the first oil inlet is connected to the first working outlet and the second working outlet, and the first oil outlet is disconnected; State 4: the first oil inlet is connected to the first working outlet, and the first oil outlet is connected to the second working outlet. The cross-sectional area of ​​cavity A2 is smaller than that of cavity A1; When the three-chamber cylinder is in rapid start-up, the four-position four-way solenoid switches to state three, which enables the hydraulic pump to connect to chambers A1 and A2 simultaneously, thereby forming a differential connection to allow the hydraulic rod to extend faster. Define p1 as the pressure in cavity A2; p2 as the pressure in cavity A3; When the three-chamber cylinder is in a rapid start-up condition with the hydraulic rod extended under no-load conditions: If p1≤first preset value and p2≤second preset value, then the first two-position three-way solenoid directional valve is connected to the first hydraulic accumulator and the A3 chamber of the three-chamber cylinder for auxiliary oil replenishment; The four-position four-way solenoid switches to state three, enabling the hydraulic pump to connect simultaneously to chambers A1 and A2, thereby forming a differential connection that allows the hydraulic rod to extend faster. If p1 < the pressure of the second hydraulic accumulator, then connect the two-position two-way solenoid directional valve to connect the second hydraulic accumulator to the outlet of the hydraulic pump for auxiliary oil replenishment. When the three-chamber cylinder is in the hydraulic rod extension position: If p1 ≤ the third preset value and the pressure of the first hydraulic accumulator > the fourth preset value, then the first two-position three-way solenoid directional valve is connected to the first hydraulic accumulator and the A3 chamber of the three-chamber cylinder for auxiliary oil replenishment. Connect the first and second position three-way solenoid directional valves to the first oil outlet and the hydraulic oil tank; The four-position four-way solenoid switches to state one, connecting the oil outlet of the hydraulic pump to chamber A1 of the three-chamber cylinder, and connecting chamber A2 to the first oil outlet. Connect the two-position two-way solenoid directional valve to connect the second hydraulic accumulator to the outlet of the hydraulic pump for auxiliary oil replenishment.

2. The rapid start-up and energy recovery system based on a three-chamber cylinder according to claim 1, characterized in that, When the three-chamber cylinder is in the hydraulic rod retraction state: If the pressure of the first hydraulic accumulator is less than or equal to the sixth preset value, it is determined that energy recovery can be performed, and the first two-position three-way solenoid directional valve is connected to the first hydraulic accumulator and the A3 chamber of the three-chamber cylinder for oil storage. If the pressure of the second hydraulic accumulator is less than or equal to the sixth preset value, it is determined that energy recovery can be performed, and the second two-position three-way solenoid valve is connected to the A1 chamber and the second hydraulic accumulator for oil storage; otherwise, the second two-position three-way solenoid valve is connected to the A1 chamber and the hydraulic oil tank. The four-position four-way solenoid switches to state four, connecting the hydraulic pump's oil outlet to chamber A2 and chamber A1 to the first oil outlet.

3. The rapid start-up and energy recovery system based on a three-chamber cylinder according to claim 2, characterized in that, Third preset value < Fourth preset value; The sixth preset value is less than the fifth preset value; First preset value < Fifth preset value < Third preset value; The second preset value is less than the fourth preset value.

4. A rapid start-up and energy recovery system based on a three-chamber cylinder according to any one of claims 1 to 3, characterized in that, The four-position four-way solenoid valve is designed so that when it is in the closed state after power failure, all four ports are disconnected.

5. A rapid start-up and energy recovery system based on a three-chamber cylinder according to any one of claims 1 to 3, characterized in that, The two-position two-way solenoid directional valve is designed to be in the open state when it is in the closed state due to power failure.

6. A rapid start-up and energy recovery system based on a three-chamber cylinder according to any one of claims 1 to 3, characterized in that, The first and second position three-way solenoid directional valve is configured such that when it is in the closed state (de-energized), chamber A3 is connected to the hydraulic oil tank, and when it is in the open state (energized), chamber A3 is connected to the first hydraulic accumulator. The second two-position three-way solenoid directional valve is configured such that when it is in the closed state (de-energized), the first return port is connected to the second hydraulic accumulator, and when it is in the open state (energized), the first return port is connected to the hydraulic oil tank.

7. A rapid start-up and energy recovery system based on a three-chamber cylinder according to any one of claims 1 to 3, characterized in that, It also includes a first relief valve, a second relief valve, and a third relief valve; The inlet of the first relief valve is connected to the outlet of the hydraulic pump; 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 outlet of the first hydraulic accumulator; the outlet of the relief valve is connected to the hydraulic oil tank. The inlet of the third relief valve is connected to the outlet of the second hydraulic accumulator; the outlet of the third relief valve is connected to the hydraulic oil tank.

8. An excavator, characterized in that, The invention includes a rapid start-up and energy recovery system based on a three-chamber cylinder as described in any one of claims 1 to 7.

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