Hydraulic system assembly, hydraulic oil recovery control method thereof and operation machine

Abstract

The invention belongs to the technical field of operation machinery and provides a hydraulic system assembly, a hydraulic oil recovery control method thereof and operation machinery. The system assembly comprises a hydraulic working system and a hydraulic oil recovery system, an oil suction opening of a recovery pump in the hydraulic oil recovery system is connected to all closed oil way modules of the hydraulic working system through a first selection module, an oil outlet of the recovery pump is connected with an oil tank, and the hydraulic oil recovery control method comprises the steps that a hydraulic oil recovery instruction is obtained; and a recovery pump is controlled to operate according to the hydraulic oil recovery instruction, and an oil suction port of the recovery pump is correspondingly controlled to be communicated with the closed oil way module according to a hydraulic oil recovery mode indicated by the hydraulic oil recovery instruction. According to the method, one-button type automatic oil discharge of all the closed oil way modules can be achieved, working points do not need to be frequently transferred, operation is greatly simplified, the recycled hydraulic oil only flows in a pipeline of a hydraulic system assembly, and pollution is avoided.

Description

Technical Field

[0001] This invention belongs to the field of construction machinery technology, specifically relating to a hydraulic system assembly and its hydraulic oil recovery control method, and construction machinery. Background Technology

[0002] Hydraulic systems used by construction machinery to perform core actions (such as excavation and lifting) generally require regular inspection and maintenance. In addition, some construction machinery involves the disassembly and assembly of external attachments when transported over long distances or when functions are changed (such as replacing the bucket and breaker of an excavator). Therefore, before hydraulic maintenance or transport of the entire machine, the oil in the relevant pipelines needs to be completely drained.

[0003] When a hydraulic system shuts down, it creates multiple independent "closed oil circuit modules" within a complex piping network. Both ends or one end of these modules are blocked. To drain the oil from these modules, the common industry practice is for operators to manually remove the corresponding plugs or connectors based on the piping layout, then allow the oil to flow out and be collected by gravity. After collection, operators determine whether to refill the oil tank or replace it with new oil based on the cleanliness of the collected oil to compensate for the system's oil shortage.

[0004] However, because these modules are scattered in different locations, operators often need to frequently change work points when recovering hydraulic oil, which not only increases labor intensity but also makes it easy to miss some. In addition, this method of draining oil exposes the hydraulic oil to the outside air, which can easily cause contamination. Summary of the Invention

[0005] To address the aforementioned deficiencies or shortcomings, this invention provides a hydraulic system assembly and its hydraulic oil recovery control method, as well as a working machine, aiming to solve the technical problems of cumbersome operation and easy oil contamination caused by the closed oil circuit draining method in the existing main hydraulic working system.

[0006] To achieve the above objectives, on one hand, the present invention provides a hydraulic system assembly and a hydraulic oil recovery control method thereof. The hydraulic system assembly includes a hydraulic working system and a hydraulic oil recovery system. When the hydraulic working system is in a non-connected oil circuit condition, it forms multiple closed oil circuit modules. The hydraulic oil recovery system includes a recovery pump and a first selection module. The suction port of the recovery pump is connected to each closed oil circuit module through the first selection module. The first selection module is used to control the selective connection of the suction port to each closed oil circuit module. The outlet of the recovery pump is connected to an oil tank. The hydraulic oil recovery control method includes: S100: Receive hydraulic oil recovery command; S200: Controls the operation of the recovery pump according to the hydraulic oil recovery command, and controls the connection between the oil suction port of the recovery pump and the closed oil circuit module according to the hydraulic oil recovery method indicated by the hydraulic oil recovery command.

[0007] In this embodiment, the hydraulic oil recovery method indicated by the hydraulic oil recovery command includes sequential hydraulic oil recovery; According to the hydraulic oil recovery method indicated by the hydraulic oil recovery command, the corresponding control is activated between the oil suction port of the recovery pump and the closed oil circuit module, specifically including: The control system connects the oil inlet of the recovery pump to each closed oil circuit module in a preset sequence as instructed.

[0008] In this embodiment, the oil inlet of the control recovery pump is sequentially connected to each closed oil circuit module according to a preset order indicated by the command, specifically including: S201: When the oil inlet of the control recovery pump is connected to the current closed oil circuit module, monitor the oil discharge status of the current closed oil circuit module; S202: When the oil discharge of the current closed oil circuit module reaches the set condition, control the first selection module to make the recovery pump connect with the next closed oil circuit module in the preset sequence.

[0009] In this embodiment, the oil discharge status includes the expected remaining oil discharge time, and the set conditions include the expected remaining oil discharge time being lower than a set threshold. S201: When the oil inlet of the control recovery pump is connected to the currently closed oil circuit module, monitor the oil discharge status of the currently closed oil circuit module, specifically including: S201-1: When the oil inlet of the control recovery pump is connected to the current closed oil circuit module, monitor the remaining oil volume of the current closed oil circuit module corresponding to the current time correction cycle; S201-2: Calculate the expected remaining oil discharge time of the currently closed oil circuit module based on the remaining oil volume, the discharge capacity of the recovery pump, and the expected rotational speed of the recovery pump in the next time correction cycle.

[0010] In this embodiment, S201-1: When the oil inlet of the control recovery pump is connected to the currently closed oil circuit module, the remaining oil volume of the currently closed oil circuit module corresponding to the current time correction cycle is monitored, specifically including: S201-1A: Based on the displacement of the recovery pump and the rotational speed of the recovery pump in each time correction cycle from the start of the connection with the current closed oil circuit module to the current moment, calculate the amount of oil recovered by the recovery pump in each time correction cycle. S201-1B: Calculate the cumulative amount of oil recovered at the current moment based on the amount of oil recovered by the recovery pump in each time correction cycle; S201-1C: Calculate the remaining oil volume of the current closed oil circuit module based on the total oil volume of the current closed oil circuit module and the calculated cumulative recovered oil volume.

[0011] In this embodiment, the oil discharge status includes the hydraulic oil pressure in the currently closed oil circuit module, and the set conditions include a sudden drop in oil pressure or the oil pressure being lower than the set pressure. S201: When the oil inlet of the control recovery pump is connected to the currently closed oil circuit module, monitor the oil discharge status of the currently closed oil circuit module, specifically including: When the oil inlet of the control recovery pump is connected to the current closed oil circuit module, monitor the hydraulic oil pressure in the current closed oil circuit module.

[0012] In this embodiment, the hydraulic oil recovery method indicated by the hydraulic oil recovery command includes simultaneous hydraulic oil recovery. Step S200: According to the hydraulic oil recovery method indicated by the hydraulic oil recovery command, the oil suction port of the recovery pump is connected to the closed oil circuit module, specifically including: S211: Controls the oil suction port of the recovery pump to be simultaneously connected to each closed oil circuit module.

[0013] In this embodiment, after step S211: controlling the oil suction port of the recovery pump to be simultaneously connected to each closed oil circuit module, the hydraulic oil recovery control method further includes: S212: Monitors the hydraulic oil pressure in each closed oil circuit module; S213: When the oil pressure in the closed oil circuit module drops sharply or the oil pressure in the closed oil circuit module is lower than the set pressure, the oil inlet of the control recovery pump is disconnected from the closed oil circuit module.

[0014] In this embodiment, the hydraulic system assembly includes a hydraulic working system and a hydraulic oil recovery system, as well as a controller. The controller is electrically connected to the first selection module and the recovery pump and is used to execute the hydraulic oil recovery control method described above.

[0015] To achieve the above objectives, the present invention also provides a working machine, wherein the working machine includes a hydraulic system assembly according to the above description.

[0016] Through the above technical solution, the hydraulic oil recovery control method for the hydraulic system assembly provided by the embodiments of the present invention has the following beneficial effects: When the hydraulic working system is in a non-connected oil circuit condition, this method controls the recovery pump to operate according to the hydraulic oil recovery command and controls the first selection module according to the hydraulic oil recovery mode indicated by the command, so that the pump port is connected to the corresponding closed oil circuit module. This enables one-button automated oil drainage of each closed oil circuit module, eliminating the need for frequent work point relocation and greatly simplifying operation. In addition, both the hydraulic working system and the hydraulic oil recovery system are integrated into the working machinery. The hydraulic oil drawn by the recovery pump only flows within the pipeline of the hydraulic system assembly, avoiding direct oil leakage. The presence of airborne dust can cause contamination and create fire hazards. Simultaneously, using a recovery pump to force the oil from the corresponding closed-loop module to the tank significantly accelerates the oil discharge rate, saving operation time. Furthermore, after the recovery pump extracts the hydraulic oil from the closed-loop module, it directly pumps it to the tank. Therefore, the pumping process of the recovery pump on the closed-loop module in this method is essentially a recovery process of the hydraulic oil within it. This recovery ensures the total amount of hydraulic oil in the hydraulic system assembly, preventing oil depletion.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings are provided to illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating the overall steps of the hydraulic oil recovery control method for the hydraulic system assembly according to an embodiment of the present invention. Figure 2 This is a detailed step diagram of step S200 when the hydraulic oil recovery method indicated by the instruction in the embodiment of the present invention is sequential recovery; Figure 3 This is a detailed step diagram of step S201 in an embodiment of the present invention; Figure 4 This is a detailed step diagram of step S201-1 in an embodiment of the present invention; Figure 5 This is a diagram showing the specific steps of step S200 and thereafter when the hydraulic oil recovery method is simultaneous recovery as indicated by the instruction in the embodiment of the present invention. Figure 6 This is a control flowchart of the hydraulic oil recovery control method according to an embodiment of the present invention; Figure 7 This is a hydraulic schematic diagram of a hydraulic system assembly according to the first embodiment of the present invention; Figure 8 This is a hydraulic schematic diagram of a hydraulic system assembly according to the second embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures 1a. Closed oil circuit module; 11. Main pump; 12. Main valve; 13. Main actuator; 14. Pump suction main oil circuit; 15. Return oil circuit; 16. Second switching valve; 17. Third switching valve; 21. Recovery pump; 22. First directional valve; 23. First selection module; 231. Three-way ball valve; In1. First ball valve inlet; In2. Second ball valve inlet; OT. Ball valve outlet; 233. Multi-way directional valve group; 25. First switching valve; 24. First recovery oil circuit; 3. Second selection module; 4. Oil tank; T. Return oil port; 5. Liquid level sensor; 6. Motor; 7. Pressure sensor. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0021] The hydraulic system assembly and hydraulic oil recovery control method of the present invention are described below with reference to the accompanying drawings.

[0022] This invention provides a hydraulic system assembly, such as Figure 7 and Figure 8 As shown, the hydraulic system assembly includes not only the hydraulic working system for performing core operational actions (such as controlling boom extension and retraction, controlling bucket digging, and controlling turntable rotation), but also a hydraulic oil recovery system.

[0023] The hydraulic working system includes a main pump 11, a main valve 12, and a main actuator 13 for performing core operating actions. The main pump 11 supplies oil to the main actuator 13, and the main valve 12 is located between the main pump 11 and the main actuator 13 and is used to control the direction of movement of the main actuator 13. When the hydraulic working system is in a non-connected oil circuit condition, closed oil circuit modules 1a will form at multiple locations. A non-connected oil circuit condition refers to one or more local circuits in the system being disconnected from the pressure source or oil tank 4 due to the state switching of hydraulic components. For example, when the main valve 12 or other types of valves (such as a hydraulically controlled check valve) switch to the shut-off position, or when the pump stops, the system will generate a closed oil circuit module. A closed oil circuit module 1a refers to an oil circuit segment where at least one end is blocked.

[0024] The hydraulic oil recovery system includes a recovery pump 21 and a first selection module 23. The first selection module 23 includes a module outlet and multiple module inlets. The module outlet is connected to the suction port of the recovery pump 21, and the multiple module inlets are connected one-to-one to multiple closed oil circuit modules 1a. The first selection module 23 is an electrically controlled device used to selectively control the connection between one or more module inlets and the module outlet. A first recovery oil circuit 24 is also provided between the pump port of the recovery pump 21 and the oil tank 4.

[0025] Based on the aforementioned hydraulic system assembly, combined with Figure 1 , Figure 7 , Figure 8 As shown, the present invention also provides a hydraulic oil recovery control method, which includes: S100: Receive hydraulic oil recovery command; S200: Controls the operation of the recovery pump 21 according to the hydraulic oil recovery command, and controls the oil suction port of the recovery pump 21 to be connected to the closed oil circuit module 1a according to the hydraulic oil recovery method indicated by the hydraulic oil recovery command.

[0026] When the hydraulic working system is in a non-connected oil circuit condition, this method controls the recovery pump 21 to work according to the hydraulic oil recovery command, and controls the first selection module according to the hydraulic oil recovery mode indicated by the command, so that the pump port is connected to the corresponding closed oil circuit module (essentially controlling the connection between the corresponding module inlet and module outlet). In this way, one-click automated oil discharge of each closed oil circuit module 1a can be achieved without frequent changes of working point, greatly simplifying the operation. In addition, the hydraulic working system and the hydraulic oil recovery system are both integrated on the working machinery, and the hydraulic oil drawn by the recovery pump 21 only flows inside the pipeline of the hydraulic system assembly, avoiding oil contamination. Direct exposure to air can lead to contamination by external dust and create fire hazards. Meanwhile, using the recovery pump 21 to force the oil in the corresponding closed oil circuit module 1a to the oil tank 4 can greatly accelerate the oil discharge rate of the closed oil circuit module 1a and save operation time. In addition, after the recovery pump 21 extracts the hydraulic oil from the closed oil circuit module 1a, it will pump the hydraulic oil directly to the oil tank 4. That is, the process of the recovery pump 21 absorbing the closed oil circuit module 1a in this method is actually a process of recovering the hydraulic oil in the closed oil circuit module 1a. By recovering the hydraulic oil, the total amount of hydraulic oil in the hydraulic system assembly can be ensured, and oil shortage can be avoided.

[0027] like Figure 6 As shown, in this embodiment, the hydraulic oil recovery method can include sequential recovery and simultaneous recovery. Depending on the recovery method indicated by the command, the specific control details of the method will also vary slightly.

[0028] When the hydraulic oil recovery method indicated by the command is sequential recovery, the oil suction port of the recovery pump 21 is connected to the closed oil circuit module 1a according to the hydraulic oil recovery method indicated by the hydraulic oil recovery command. Specifically, this includes: The oil inlet of the control recovery pump 21 is sequentially connected to each closed oil circuit module 1a in the preset order indicated by the command.

[0029] Specifically, such as Figure 8 As shown, the non-connected oil circuit condition includes the hydraulic working system shutdown condition. Assuming that after the hydraulic working system shuts down, two closed oil circuit modules 1a are formed. One closed oil circuit module 1a is the main suction oil circuit 14 between the suction port of the main pump 11 and the oil tank 4, and the other closed oil circuit module 1a is the return oil circuit 15 between the return port T of the main valve 12 and the oil tank 4. Due to the shutdown of the main pump 11 or the switching of the main valve 12 to the neutral shut-off position, one end of the main suction oil circuit 14 and the return oil circuit 15 is blocked.

[0030] When the hydraulic oil recovery method indicated by the command is sequential recovery, if the recovery order is to first recover the hydraulic oil in the main suction circuit 14 and then recover the hydraulic oil in the return circuit 15, the system assembly can control the first selection module 23 according to the command, so that the suction port of the recovery pump 21 is first connected to the main suction circuit 14. Then, after the recovery pump 21 draws the hydraulic oil in the main suction circuit 14 to the required level, the first selection module 23 is switched to connect the suction port of the recovery pump 21 to the return circuit 15. By controlling the recovery pump 21 to sequentially connect the two closed circuit modules 1a, the sequential recovery of hydraulic oil in the two closed circuit modules 1a is achieved.

[0031] like Figure 2 As shown, in this embodiment, the oil inlet of the control recovery pump 21 is sequentially connected to each closed oil circuit module 1a according to a preset order indicated by the command, specifically including: S201: When the oil inlet of the control recovery pump 21 is connected to the current closed oil circuit module 1a, monitor the oil discharge status of the current closed oil circuit module 1a; S202: When the oil discharge of the current closed oil circuit module 1a reaches the set condition, the first selection module 23 is controlled so that the recovery pump 21 is connected to the next closed oil circuit module 1a in the preset sequence.

[0032] After the recovery pump 21 reduces the amount of hydraulic oil in the currently connected closed oil circuit module 1a to a certain value, the recovery pump 21 will experience dry suction. To reduce the duration of dry suction, the oil discharge status of the recovery pump 21 to the currently connected closed oil circuit module 1a can be monitored. When the oil discharge status of the recovery pump 21 to the current closed oil circuit module 1a meets the set conditions, the first selection module 23 is controlled to disconnect the recovery pump 21 from the current closed oil circuit module 1a and connect it to the next closed oil circuit module 1a in the recovery sequence indicated by the command. In this way, orderly oil discharge from each closed oil circuit module 1a can be achieved, ensuring that the recovery pump 21 is in a safe working state and minimizing the duration of dry suction. It should be noted that when the recovery pump 21 discharges oil from the next closed oil circuit module 1a, the next closed oil circuit module 1a will become the current closed oil circuit module 1a.

[0033] In this embodiment, the oil discharge status can be the expected remaining oil discharge time, and the set condition can be that the expected remaining oil discharge time is lower than a set threshold. Correspondingly, such as... Figure 3 As shown, S201: When the oil inlet of the control recovery pump 21 is connected to the current closed oil circuit module 1a, the oil discharge status of the current closed oil circuit module 1a is monitored, specifically including: S201-1: When the oil inlet of the control recovery pump 21 is connected to the current closed oil circuit module 1a, monitor the remaining oil quantity of the current closed oil circuit module 1a corresponding to the current time correction cycle. S201-2: Calculate the expected remaining oil discharge time of the currently closed oil circuit module 1a based on the remaining oil volume, the displacement of the recovery pump 21, and the expected rotational speed of the recovery pump 21 in the next time correction cycle.

[0034] When the expected remaining drainage time of the current closed oil circuit module 1a is lower than the set threshold, it indicates that the oil in the current closed oil circuit module 1a has been completely pumped out, or even if a small amount of oil remains, it will cause the recovery pump 21 to draw oil dry, or the oil will not affect the disassembly and inspection of subsequent hydraulic components. In this case, the recovery pump 21 can be controlled to stop draining oil from the current closed oil circuit module 1a and start draining oil from the next closed oil circuit module 1a. By using the expected remaining drainage time as the trigger condition for sequential oil pumping switching, the system can achieve automatic, orderly, and safe oil drainage from the recovery pump, while eliminating the dependence on the pressure sensor 7, resulting in lower system construction costs and a smaller overall space occupation.

[0035] Furthermore, such as Figure 4 As shown, in this embodiment, S201-1: When the oil inlet of the control recovery pump 21 is connected to the current closed oil circuit module 1a, the remaining oil quantity of the current closed oil circuit module 1a corresponding to the current time correction cycle is monitored, specifically including: S201-1A: Based on the displacement of the recovery pump 21 and the rotational speed of the recovery pump 21 in each time correction cycle from the start of the connection with the currently closed oil circuit module 1a to the current moment, calculate the amount of oil recovered by the recovery pump 21 in each time correction cycle. S201-1B: Calculate the cumulative amount of oil recovered at the current moment based on the amount of oil recovered by the recovery pump 21 in each time correction cycle; S201-1C: Calculate the remaining oil volume of the current closed oil circuit module 1a based on the total oil volume of the current closed oil circuit module 1a and the calculated cumulative recovered oil volume.

[0036] When the recovery pump 21 drains oil from the closed oil circuit module 1a, the speed and real-time flow rate of the recovery pump 21 will change continuously due to factors such as the drop in liquid level and pressure changes in the closed oil circuit module 1a. Therefore, the amount of remaining oil in the closed oil circuit module 1a does not decrease uniformly.

[0037] To accurately calculate the expected remaining oil discharge time, this method can first incorporate a time correction cycle into the system assembly. t, starting from the connection between the recovery pump 21 and the currently closed oil circuit module 1a, after each time correction cycle If t, then the remaining oil volume and expected remaining oil discharge time will be recalculated.

[0038] Assuming that when the recovery pump 21 is just connected to one of the closed oil circuit modules 1a, the recovery pump 21 operates at a displacement of D and a speed of n[1], and the total oil volume in the closed oil circuit module 1a is At this point, the expected remaining oil discharge time should be: .

[0039] As the oil extraction continues, the remaining oil extraction time is expected to be adjusted over time. The passage of t is constantly being corrected, such as when When t is 0.5s, it means that from the start of conduction, the expected remaining oil discharge time will be adjusted sequentially every 0.5s.

[0040] When the time point reaches the k-th time correction cycle, assuming the rotational speed of recovery pump 21 becomes n[k], then the amount of oil that has been pumped out from the closed oil circuit module 1a... The remaining oil volume of the closed oil circuit module 1a ;in, For the (k-1)th time correction period, the remaining oil volume in the closed oil circuit module 1a, the formula for calculating the amount of oil that has already been removed can also be expressed as follows: ;in, This represents the amount of oil discharged by the recovery pump 21 during the k-th time correction cycle.

[0041] After calculating the remaining oil, simply follow the formula. This allows us to calculate the remaining time required for the recovery pump 21 to empty the remaining hydraulic oil in the currently closed oil circuit module 1a at the current moment.

[0042] It should be noted that when calculating the remaining time... At that time, the rotational speed of the recovery pump 21 is the expected rotational speed of the recovery pump 21 in the next time correction cycle after the current moment. Expected rotational speed The calculation formula is: Where α is a correction coefficient. By predicting the rotational speed of the recovery pump 21, the prediction result of the remaining oil discharge time is made more accurate.

[0043] Through the above calculations, the system assembly can dynamically and accurately predict the remaining recovery time and total oil discharge time of the current closed oil circuit module 1a based on the real-time operation of the recovery pump 21. This ensures that the system assembly can automatically command the recovery pump 21 to switch to discharging oil from the next closed oil circuit module 1a when the oil discharge level of the current closed oil circuit module 1a reaches the preset threshold. This ensures that the oil in each closed oil circuit module 1a is fully and orderly recovered, while minimizing the time that the recovery pump 21 may experience dry suction.

[0044] like Figure 6 As shown, in this embodiment, monitoring the oil discharge status of the currently closed oil circuit module 1a can also be used to monitor the pressure of the hydraulic oil inside the currently closed oil circuit module 1a.

[0045] When the recovery pump 21 drains oil from the closed oil circuit module 1a, if the amount of oil in the closed oil circuit module 1a is sufficient, theoretically the pressure of the hydraulic oil in the current closed oil circuit module 1a should gradually decrease. When a sudden drop in pressure occurs at a certain moment, it indicates that the oil draining of the module has entered a critical state, and the degree of oil draining in the module has reached a preset threshold. By using whether the hydraulic oil pressure in the closed oil circuit module 1a experiences a sudden drop as the criterion for whether the recovery pump 21 switches to drain oil from the next closed oil circuit module 1a, it ensures that the oil in each closed oil circuit module 1a is fully and orderly recovered, and also minimizes the time that the recovery pump 21 may experience dry suction.

[0046] Of course, such as Figure 6 As shown, the setting condition can also be that the hydraulic oil pressure in the current closed oil circuit module 1a is lower than the set pressure. If the hydraulic oil pressure in the current closed oil circuit module 1a drops to a very low value, it can also indicate that the current module's oil discharge completion has reached the critical point.

[0047] In this embodiment, S201: When the oil inlet of the control recovery pump 21 is connected to the current closed oil circuit module 1a, the oil discharge status of the current closed oil circuit module 1a is monitored, specifically including: When the oil inlet of the control recovery pump 21 is connected to the current closed oil circuit module 1a, the hydraulic oil pressure in the current closed oil circuit module 1a is monitored.

[0048] By monitoring the hydraulic oil pressure within the closed oil circuit module 1a, the system assembly can obtain real-time hydraulic oil pressure data within the closed oil circuit module 1a.

[0049] like Figure 5 and Figure 6 As shown, in this embodiment, the hydraulic oil recovery method also includes a simultaneous recovery method. When the hydraulic oil recovery method indicated by the command is simultaneous recovery, step S200: according to the hydraulic oil recovery method indicated by the hydraulic oil recovery command, the oil suction port of the recovery pump 21 is connected to the closed oil circuit module 1a, specifically including: S211: Control the oil suction port of recovery pump 21 to be simultaneously connected to each closed oil circuit module 1a.

[0050] By controlling the oil suction port of the recovery pump 21 to be simultaneously connected to each closed oil circuit module 1a, the recovery pump 21 can simultaneously discharge oil from all closed oil circuit modules 1a.

[0051] When the recovery pump 21 simultaneously draws hydraulic oil from each closed oil circuit module 1a, the changes in hydraulic oil pressure and remaining oil volume within each closed oil circuit module 1a are quite complex. Therefore, relying on the remaining oil volume as the setting condition for disconnecting the drain may affect the draining effect. To cut off the draining of the closed oil circuit module 1a at the appropriate time, such as... Figure 5 As shown, in this embodiment, after step S211: controlling the oil suction port of the recovery pump 21 to be simultaneously connected to each closed oil circuit module 1a, the hydraulic oil recovery control method further includes: S212: Monitor the hydraulic oil pressure in each closed oil circuit module 1a; S213: When the oil pressure in the closed oil circuit module 1a drops sharply or the oil pressure in the closed oil circuit module 1a is lower than the set pressure, the oil inlet of the control recovery pump 21 is disconnected from the closed oil circuit module 1a.

[0052] By triggering the hydraulic oil pressure change rate at a singularity or below a set pressure, the connection between the recovery pump 21 and the closed oil circuit module 1a that has completed oil discharge can be disconnected in time when the recovery pump 21 completes the oil discharge of a certain module. This prevents hydraulic oil from other closed oil circuit modules 1a from flowing into the closed oil circuit module 1a, which would affect the oil discharge rate and the oil discharge effect.

[0053] In this embodiment, the hydraulic oil recovery system can be an auxiliary hydraulic system for the operating machinery. The specific forms of the auxiliary hydraulic system are varied, such as a pilot control system that provides low-pressure control oil for the entire system assembly, a braking and steering system that ensures driving safety, a heat dissipation circulation system that cools down key components, and a folding ladder drive system for the unfolding and folding of climbing ladders in large operating machinery.

[0054] like Figure 7 and Figure 8 As shown, in order to realize the switching between auxiliary operation and hydraulic oil recovery function of hydraulic oil recovery system, hydraulic oil recovery system also needs to include a first directional valve 22 and a first switching valve 25. The first directional valve 22 is used to control the working direction of auxiliary action execution unit, and the first switching valve 25 is set on the first recovery oil circuit 24 between the pump oil port of recovery pump 21 and oil tank 4.

[0055] When the auxiliary action execution unit in the auxiliary hydraulic system needs to work normally, the oil output by the recovery pump 21 can flow to the first directional valve 22 by closing the first switching valve 25. When it is necessary to drain oil from the closed oil circuit module 1a in the hydraulic working system, the recovery pump 21 can pump the hydraulic oil drawn from the closed oil circuit module 1a to the oil tank 4 by controlling the opening of the first switching valve 25.

[0056] In this embodiment, the hydraulic system assembly includes a hydraulic working system and a hydraulic oil recovery system, as well as a controller. The controller is electrically connected to the first selection module 23 and the recovery pump 21 and is used to execute the hydraulic oil recovery control method according to the hydraulic system assembly described above. Since the hydraulic system assembly adopts all the technical solutions of the above embodiments, it has at least the beneficial effects brought by the above embodiments, which will not be repeated here.

[0057] like Figure 8 As shown, in this embodiment, for the two closed oil circuit modules 1a, namely the pump suction main oil circuit 14 and the return oil circuit 15, since one end of both is connected to the oil tank 4, when the recovery pump 21 discharges oil from the two closed oil circuit modules 1a, in order to prevent the oil in the oil tank 4 from flowing back, a second switching valve 16 can be set at the end of the pump suction main oil circuit 14 near the oil tank 4, and a third switching valve 17 can be set at the end of the return oil circuit 15 near the oil tank 4.

[0058] In this embodiment, depending on the number of closed oil circuit modules 1a formed when the hydraulic working system stops, the first selection module 23 can be adaptively set. For example, when the hydraulic working system only forms two closed oil circuit modules 1a, namely the pump suction main oil circuit 14 and the return oil circuit 15, when it stops, the first selection module 23 is either an electrically controlled three-way solenoid valve or an electrically controlled three-way ball valve 231.

[0059] Taking the electrically controlled swivel three-way ball valve 231 as an example, such as Figure 8 As shown, the three-way ball valve 231 has a first ball valve inlet In1, a second ball valve inlet In2, and a ball valve outlet OT. The first ball valve inlet In1 and the second ball valve inlet In2 correspond to multiple module inlets of the first selection module 23, and the ball valve outlet OT corresponds to the module outlet of the first selection module 23. The oil circuit of the first ball valve inlet In1 is connected to the pump suction main oil circuit 14, the oil circuit of the second ball valve inlet In2 is connected to the return oil circuit 15, and the ball valve outlet OT is connected to the pump suction port of the recovery pump 21.

[0060] When it is necessary to drain oil from the main pump suction circuit 14, adjust the three-way ball valve 231 to the position where the inlet In1 and outlet OT of the first ball valve are connected, and control the first switching valve 25 to open, controlling the recovery pump 21 to run. At this time, the hydraulic oil in the main pump suction circuit 14 will flow back to the oil tank 4 through the inlet In1 of the first ball valve, the outlet OT of the ball valve, the suction port of the recovery pump 21, the discharge port of the recovery pump 21, and the first switching valve 25 in sequence. Through the active suction of the recovery pump 21, the oil in the main pump suction circuit 14 can be quickly discharged.

[0061] When the pump finishes pumping oil from the main oil circuit 14, the three-way ball valve 231 is adjusted to the position where the inlet In2 of the second ball valve is connected to the outlet OT of the ball valve, so that the recovery pump 21 can continue to pump hydraulic oil from the return oil circuit 15.

[0062] After both closed oil circuit modules 1a have completed oil discharge, the recovery pump 21 can be stopped and the first switch valve 25 can be closed.

[0063] It is understandable that when the number of closed oil circuit modules 1a is multiple, this first selection module 23 can be either a manually operated single valve or an electrically controlled single valve with multi-channel switching function, or it can be a multi-channel directional valve group 233 formed by multiple small-channel valves connected in parallel, such as... Figure 7 The multi-way directional valve group 233 shown consists of multiple two-position two-way solenoid directional valves.

[0064] like Figure 7 As shown, in this embodiment, the hydraulic system assembly may also include multiple pressure sensors 7, which can be used to detect the oil pressure of each closed oil circuit module 1a and the oil suction working oil circuit of the recovery pump 21 respectively.

[0065] like Figure 7 and Figure 8 As shown, in this embodiment, a liquid level sensor 5 can also be installed at the oil tank 4. When the recovery pump 21 is performing oil suction and discharge operation on the closed oil circuit module 1a, if the liquid level sensor 5 senses that the oil level in the oil tank 4 reaches the critical value, the recovery pump 21 can be controlled to stop to stop the oil suction operation.

[0066] In this embodiment, the liquid level sensor 5 can be a float type, capacitive type, photoelectric type, etc.

[0067] like Figure 7 and Figure 8 As shown, in this embodiment, the auxiliary hydraulic system also includes a second selection module 3. The module outlet can be connected to the oil suction port of the recovery pump 21 through the second selection module 3. The second selection module 3 is also connected to the oil tank 4. The second selection module 3 is used to selectively control one of the module outlet and the oil tank 4 to be connected to the oil suction port of the recovery pump 21.

[0068] When the recovery pump 21 needs to draw oil from the closed oil circuit module 1a, the second selection module 3 can be switched to the state where the recovery pump 21 and the first selection module 23 are connected. When the auxiliary action execution unit in the auxiliary hydraulic system needs to work, the second selection module 3 can be switched to the state where the oil suction port of the recovery pump 21 is connected to the oil tank 4. At this time, the recovery pump 21 can draw oil from the oil tank 4 and pressurize it to the first reversing valve 22.

[0069] In this embodiment, the second selection module 3 can also be a single valve with multi-channel switching function, just like the first selection module 23, or a multi-channel directional valve group 233 formed by multiple single valves with few channels connected in parallel.

[0070] In this embodiment, the aforementioned single valve can refer to a ball valve, plug valve, slide valve, multi-way valve, etc.

[0071] In this embodiment, the switching valve can be a butterfly valve, ball valve, directional shut-off valve, etc.

[0072] In this embodiment, the recovery pump 21 can be driven by the motor 6. Of course, the recovery pump 21 can also be driven by an engine.

[0073] To achieve the above objectives, the present invention also provides a working machine, wherein the working machine includes a hydraulic system assembly according to the above-described working machine. Since the working machine adopts all the technical solutions of the above embodiments, it at least possesses the beneficial effects brought by the above embodiments, and will not be repeated here.

[0074] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0075] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0076] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0077] Although embodiments of the present invention have been described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for controlling hydraulic oil recovery in a hydraulic system assembly, characterized in that, The hydraulic system assembly includes a hydraulic working system and a hydraulic oil recovery system. The hydraulic working system forms multiple closed oil circuit modules (1a) when the oil circuit is not connected. The hydraulic oil recovery system includes a recovery pump (21) and a first selection module (23). The suction port of the recovery pump (21) is connected to each of the closed oil circuit modules (1a) through the first selection module (23). The first selection module (23) is used to control the suction port to selectively connect with each of the closed oil circuit modules (1a). The outlet of the recovery pump (21) is connected to the oil tank (4). The hydraulic oil recovery control method includes: Receive hydraulic oil recovery command; The recovery pump (21) is controlled to operate according to the hydraulic oil recovery command, and the oil suction port of the recovery pump (21) is connected to the closed oil circuit module (1a) according to the hydraulic oil recovery method indicated by the hydraulic oil recovery command.

2. The hydraulic oil recovery control method for a hydraulic system assembly according to claim 1, characterized in that, The hydraulic oil recovery command indicates a hydraulic oil recovery method including sequential hydraulic oil recovery; According to the hydraulic oil recovery method indicated by the hydraulic oil recovery command, the oil inlet of the recovery pump (21) is connected to the closed oil circuit module (1a), specifically including: The oil inlet of the recovery pump (21) is controlled to sequentially connect each of the closed oil circuit modules (1a) in a preset order as indicated by the instruction.

3. The hydraulic oil recovery control method for the hydraulic system assembly according to claim 2, characterized in that, Controlling the oil inlet of the recovery pump (21) to sequentially connect each of the closed oil circuit modules (1a) according to the preset sequence indicated by the command, specifically including: When the oil inlet of the recovery pump (21) is connected to the current closed oil circuit module (1a), the oil discharge status of the current closed oil circuit module (1a) is monitored; When the oil discharge of the current closed oil circuit module (1a) reaches the set condition, the first selection module (23) is controlled so that the recovery pump (21) is connected to the next closed oil circuit module (1a) in the preset sequence.

4. The hydraulic oil recovery control method for the hydraulic system assembly according to claim 3, characterized in that, The oil discharge status includes the expected remaining oil discharge time, and the setting condition includes the expected remaining oil discharge time being lower than a set threshold. When the oil inlet of the recovery pump (21) is connected to the current closed oil circuit module (1a), the oil discharge status of the current closed oil circuit module (1a) is monitored, specifically including: When the oil inlet of the recovery pump (21) is connected to the current closed oil circuit module (1a), the remaining oil volume of the current closed oil circuit module (1a) corresponding to the current time correction cycle is monitored; Based on the remaining oil volume, the discharge capacity of the recovery pump (21), and the expected rotational speed of the recovery pump (21) in the next time correction cycle, the expected remaining oil discharge time of the current closed oil circuit module (1a) is calculated.

5. The hydraulic oil recovery control method for the hydraulic system assembly according to claim 4, characterized in that, When the oil inlet of the recovery pump (21) is connected to the current closed oil circuit module (1a), the remaining oil volume of the current closed oil circuit module (1a) corresponding to the current time correction cycle is monitored, specifically including: Based on the displacement of the recovery pump (21) and the rotational speed of the recovery pump (21) in each time correction cycle from the start of the connection with the current closed oil circuit module (1a) to the current moment, calculate the amount of oil recovered by the recovery pump (21) in each time correction cycle. The cumulative amount of oil recovered at the current moment is calculated based on the amount of oil recovered by the recovery pump (21) in each time correction period. The remaining oil volume of the current closed oil circuit module (1a) is calculated based on the total oil volume of the current closed oil circuit module (1a) and the calculated cumulative recovered oil volume.

6. The hydraulic oil recovery control method for the hydraulic system assembly according to claim 3, characterized in that, The oil discharge status includes the hydraulic oil pressure in the current closed oil circuit module (1a), and the set conditions include a sudden drop in oil pressure or the oil pressure being lower than the set pressure. When the oil inlet of the recovery pump (21) is connected to the current closed oil circuit module (1a), the oil discharge status of the current closed oil circuit module (1a) is monitored, specifically including: When the oil inlet of the recovery pump (21) is connected to the current closed oil circuit module (1a), the hydraulic oil pressure in the current closed oil circuit module (1a) is monitored.

7. The hydraulic oil recovery control method for a hydraulic system assembly according to claim 1, characterized in that, The hydraulic oil recovery command indicates a hydraulic oil recovery method including simultaneous hydraulic oil recovery. Based on the hydraulic oil recovery method indicated by the command, the suction port of the recovery pump (21) is connected to the closed oil circuit module (1a), specifically including: The oil inlet of the recovery pump (21) is simultaneously connected to each of the closed oil circuit modules (1a).

8. The hydraulic oil recovery control method for a hydraulic system assembly according to claim 7, characterized in that, After controlling the oil suction port of the recovery pump (21) to be simultaneously connected to each of the closed oil circuit modules (1a), the hydraulic oil recovery control method further includes: Monitor the hydraulic oil pressure within each of the aforementioned closed oil circuit modules (1a); When the oil pressure in the closed oil circuit module (1a) drops sharply or the oil pressure in the closed oil circuit module (1a) is lower than the set pressure, the oil inlet of the recovery pump (21) is disconnected from the closed oil circuit module (1a).

9. A hydraulic system assembly, characterized in that, The hydraulic system assembly includes: A hydraulic working system, wherein the hydraulic working system forms multiple closed oil circuit modules (1a) when the oil circuit is not connected. The hydraulic oil recovery system includes a recovery pump (21) and a first selection module (23). The oil suction port of the recovery pump (21) is connected to each of the closed oil circuit modules (1a) through the first selection module (23). The first selection module (23) is used to control the oil suction port to selectively connect with each of the closed oil circuit modules (1a). The oil outlet of the recovery pump (21) is connected to the oil tank (4). The controller is electrically connected to the first selection module (23) and the recovery pump (21) and is used to perform the hydraulic oil recovery control method of the hydraulic system assembly according to any one of claims 1 to 8.

10. A type of operating machinery, characterized in that, The operating machinery includes the hydraulic system assembly as described in claim 9.

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