A potential energy recovery system with segmented speed regulation function

Abstract

The application discloses a potential energy recovery system with segmented speed regulation function, and relates to the technical field of energy recovery.The potential energy recovery system with segmented speed regulation function comprises a lifting oil cylinder, a first pressure sensor arranged in a rodless cavity of the lifting oil cylinder, an oil supply module provided with an oil tank and an oil supply assembly, a valve control module for decompressing pressure oil provided by the oil supply assembly and controlling the reversing of the pressure oil, an energy recovery module provided with a shunt assembly and a potential energy recovery device, and a controller.The potential energy recovery system with segmented speed regulation function provided by the application avoids the setting of a speed limiting valve in a traditional hydraulic system, reduces throttling loss, reduces energy loss caused by system heating, and has good energy saving effect.The control precision of the descending speed of the lifting oil cylinder is improved, the corresponding speed is fast, and the recovery process is intelligent and efficient.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of energy recovery, more particularly, to a potential energy recovery system with segmented speed regulation function. BACKGROUND

[0002] Industrial vehicles (forklifts), excavators, loaders, stackers, aerial work platforms and other handling equipment will use hydraulic systems to drive their lifting components to work. During the handling process, the load gravity potential energy cannot be effectively utilized during the frequent lifting and lowering process. To control the lowering speed, a speed limiting valve, a throttle valve, a reversing valve and other components are arranged in the lowering circuit to form a valve control system, which relies on throttling to control the lowering speed. However, the valve control makes the potential energy mostly directly or indirectly consumed in the hydraulic system in the form of heat energy, resulting in an increase in oil temperature. The increase in temperature not only accelerates the oxidation speed of the oil, reduces the viscosity of the oil, and reduces the overall working efficiency of the hydraulic system, but also accelerates the aging of related components, affecting the service life and transmission efficiency of the hydraulic system.

[0003] In the prior art, a forklift potential energy recovery system and control method are disclosed, which controls the pump motor speed through motor speed regulation to achieve speed control of the system, and switches the lifting and lowering actions by changing the rotation direction of the motor. This control method has complex working conditions, and the motor needs to be frequently started and stopped, or even switched between electric mode and generating mode. The motor has large rotational inertia, resulting in slow response speed during action switching, which affects user experience satisfaction. The current fluctuates greatly during the working process, and the working temperature is high, which reduces the service life of the pump motor and is often accompanied by problems such as vibration and noise.

[0004] The potential energy recovery system based on variable speed volume speed regulation has a poorer control effect than the valve control system, especially during the low-speed lowering process. The generator will be in a low-speed region, and the motor has poor control accuracy at low speed, which will inevitably affect the control of the lowering speed. At the same time, the generator is usually in a low-efficiency region at low speed, and the system recovery efficiency will be low, so potential energy recovery is no longer suitable at this time. During the lowering process, the system needs to provide certain energy to control the lowering speed. When the recovery power during the lowering process is not enough to overcome the minimum loss of the system, if potential energy recovery is still used, the system will be in an energy consumption state.

[0005] In summary, how to improve the control accuracy and potential energy recovery efficiency during potential energy recovery is a problem that needs to be solved by those skilled in the art. SUMMARY

[0006] Therefore, the potential energy recovery system with segmented speed regulation function is provided, the setting of the speed limiting valve in the traditional hydraulic system is avoided, the throttling loss is reduced, the energy recovery is carried out in the variable speed volume speed regulation mode, the energy loss caused by system heating is reduced, the energy saving effect is good. In the slow descending process, the valve control module is used for controlling the descending speed, the control precision of the descending speed of the lifting oil cylinder is improved. In the use process, whether the descending process of the lifting oil cylinder has the recovery value can be automatically judged according to the actual working condition, the corresponding speed is fast, and the recovery process is intelligent and efficient.

[0007] In order to realize the above-mentioned purpose, the technical scheme provided by the present application is as follows:

[0008] A potential energy recovery system with segmented speed regulation function comprises:

[0009] A lifting oil cylinder, whose rod cavity is connected to an oil tank, is provided with a first pressure sensor for detecting the pressure of the rodless cavity;

[0010] An oil supply module is provided with an oil tank and an oil supply assembly for supplying oil to the potential energy recovery system;

[0011] A valve control module is connected between the oil supply module and the rodless cavity of the lifting oil cylinder, and is used for reducing the pressure of the pressure oil provided by the oil supply assembly and controlling the reversing of the pressure oil;

[0012] An energy recovery module is connected to the rodless cavity of the lifting oil cylinder, and is provided with a shunt assembly and a potential energy recovery device, the shunt assembly is used for shunting the pressure oil flowing through the energy recovery module;

[0013] A controller is used for receiving the pressure value measured by the first pressure sensor, and selecting to start the valve control module or the energy recovery module according to the pressure value measured by the first pressure sensor and a preset minimum pressure value;

[0014] The oil supply module, the valve control module and the energy recovery module are connected with the controller.

[0015] Optionally, the shunt assembly comprises a recovery switching valve, a shunt valve and an electromagnetic reversing valve;

[0016] The oil inlet of the recovery switching valve is connected with the rodless cavity of the lifting oil cylinder, the oil outlet of the recovery switching valve is connected with the oil inlet of the shunt valve, one oil outlet of the shunt valve is connected with the oil inlet of the electromagnetic reversing valve, the other oil outlet of the shunt valve is connected with the potential energy recovery device, and the oil outlet of the electromagnetic reversing valve is connected with the oil tank;

[0017] The recovery switching valve and the electromagnetic reversing valve are connected with the controller.

[0018] Optionally, the flow distribution valve is a three-way flow regulating valve, an oil inlet of the three-way flow regulating valve is connected to the rodless chamber of the lifting cylinder, a first oil outlet of the three-way flow regulating valve is connected to the electromagnetic reversing valve, and a second oil outlet of the three-way flow regulating valve is connected to the potential energy recovery device.

[0019] Optionally, a damping hole is arranged between the oil inlet and the first oil outlet of the three-way flow regulating valve, the oil inlet of the three-way flow regulating valve is in communication with a springless side of the three-way flow regulating valve, and the first oil outlet is in communication with a spring side of the three-way flow regulating valve.

[0020] Optionally, the potential energy recovery device comprises a hydraulic motor and a generator driven to rotate by the hydraulic motor.

[0021] The oil outlets of the flow distribution valve and the electromagnetic reversing valve are connected to an oil inlet of the hydraulic motor, and an oil outlet of the hydraulic motor is connected to the oil tank.

[0022] The generator is connected to the controller.

[0023] Optionally, the potential energy recovery device comprises a supplemental oil check valve arranged in parallel with the oil inlet and the oil outlet of the hydraulic motor, and when the hydraulic motor is in a vacuum state, pressure oil is supplemented from the oil tank to the hydraulic motor through the supplemental oil check valve.

[0024] Optionally, the oil inlet of the hydraulic motor is provided with a second pressure sensor for detecting the pressure of the oil inlet of the hydraulic motor.

[0025] The second pressure sensor is connected to the controller.

[0026] Optionally, the oil supply assembly comprises an electric motor, a variable pump, and a first check valve arranged at an oil outlet of the variable pump, the first check valve is connected to the valve control module, the electric motor is connected to the variable pump and drives the variable pump to rotate.

[0027] The electric motor is connected to the controller.

[0028] Optionally, the valve control module comprises a pressure compensator, a pilot pressure reducing valve, a first electric proportional pressure reducing valve, a second electric proportional pressure reducing valve, and a throttling reversing valve, the pressure compensator and the pilot pressure reducing valve are connected to the oil supply assembly, the first electric proportional pressure reducing valve, the second electric proportional pressure reducing valve, and the energy recovery module are connected to an oil outlet of the pilot pressure reducing valve.

[0029] The working oil port of the first electric proportional pressure reducing valve and the working oil port of the second electric proportional pressure reducing valve are connected with the upper end and the lower end of the throttle reversing valve respectively to drive the throttle reversing valve to reverse, and the pressure compensator is connected with the throttle reversing valve.

[0030] The first electric proportional pressure increasing valve and the second electric proportional pressure increasing valve are connected with the controller.

[0031] Optionally, the output end of the pilot pressure reducing valve is provided with a second check valve and an accumulator, one end of the second check valve is connected with the output end of the pilot pressure reducing valve, the other end is connected with the accumulator, and the first electric proportional pressure reducing valve and the second electric proportional pressure reducing valve are connected with the accumulator.

[0032] Optionally, an overflow valve connected with the throttle reversing valve in parallel is further included, and the overflow valve is used to limit the working oil port pressure of the throttle reversing valve.

[0033] In the process of using the potential energy recovery system with segmented speed regulation function provided by the application, when the lifting oil cylinder rises, the oil supply assembly in the oil supply module extracts oil from the oil tank and supplies oil to the valve control module, the valve control module reduces the pressure oil supplied by the oil supply assembly, and supplies the reduced pressure oil to the energy recovery module, the valve control module communicates with the rodless cavity of the lifting oil cylinder, so that the pressure oil enters the rodless cavity of the lifting oil cylinder through the valve control module, the pressure in the rodless cavity of the lifting oil cylinder is increased, and the lifting oil cylinder is driven to rise, when the lifting oil cylinder rises to a preset height, the valve control module stops supplying oil to the rodless cavity of the lifting oil cylinder, so that the lifting oil cylinder remains at the preset height.

[0034] When the lifting oil cylinder needs to descend, the valve control module or the energy recovery module can be opened according to actual needs.

[0035] When the lifting oil cylinder needs to descend slowly, and the pressure in the rodless cavity of the lifting oil cylinder is less than a preset minimum pressure value, at this time, the potential energy recovery value is not available, the valve control module can be opened, and the throttling descending mode is adopted without energy recovery; the pressure oil in the rodless cavity of the lifting oil cylinder flows to the valve control module and returns to the oil tank through the valve control module, and after the lifting oil cylinder descends by a certain distance, the related valve core in the valve control module can be controlled to move to a position to prevent the pressure oil from continuing to flow into the oil tank, so that the lifting oil cylinder remains at the required height; in this process, the valve control module can be used to control the descending speed of the lifting oil cylinder, which is suitable for the case that the descending speed of the lifting oil cylinder is slow and the control precision of the descending speed is high, and can effectively improve the control of the descending precision of the lifting oil cylinder.

[0036] When the lift cylinder descends and the pressure in the rodless chamber of the lift cylinder is greater than or equal to a preset minimum pressure value, the energy recovery module is activated. When the lift cylinder descends at a speed less than or equal to a preset speed, the energy recovery module is activated, and the pressurized oil in the rodless chamber of the lift cylinder flows back to the oil tank through the diverter assembly. When the lift cylinder descends and the pressure in the rodless chamber of the lift cylinder is greater than the preset minimum pressure value and the lift cylinder descends at a speed greater than a preset speed, part of the pressurized oil flows through the diverter assembly and the potential energy recovery device in sequence to recover the potential energy of the pressurized oil.

[0037] Compared to existing technologies, the potential energy recovery system with segmented speed regulation provided by the present invention avoids the need for a speed-limiting valve in traditional hydraulic systems, reducing throttling losses. It utilizes variable speed and volumetric speed regulation for energy recovery, reducing energy losses caused by system heating and achieving excellent energy-saving effects. During the slow descent process, a valve control module is used to control the descent speed, improving the control accuracy of the lift cylinder's descent speed. Furthermore, during use, the system can automatically determine whether the lift cylinder's descent process is worth recovering based on actual operating conditions, resulting in a fast response time and an intelligent and efficient recovery process. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0039] Figure 1 This is a structural schematic diagram of a specific embodiment of the potential energy recovery system with segmented speed regulation function provided by the present invention.

[0040] Figure 1 middle:

[0041] Oil tank 1, variable pump 2, electric motor 3, first one-way valve 4, throttle reversing valve 5, pressure compensator 6, relief valve 7, first electric proportional pressure reducing valve 8, second electric proportional pressure reducing valve 9, accumulator 10, second one-way valve 11, pilot pressure reducing valve 12, lifting cylinder 13, first pressure sensor 14, recovery switching valve 15, diverter valve 16, solenoid reversing valve 17, second pressure sensor 18, generator 19, hydraulic motor 20, oil replenishment one-way valve 21. DETAILED DESCRIPTION

[0042] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0043] The core of the present application is to provide a potential energy recovery system with segmented speed regulation function, which avoids the setting of a speed limiting valve in a traditional hydraulic system, reduces throttling loss, adopts a variable speed volume speed regulation method for energy recovery, reduces energy loss caused by system heating, and has good energy saving effect. In the slow descending process, the valve control module is used to control the descending speed, thereby improving the control accuracy of the descending speed of the lifting cylinder. In use, the descending process of the lifting cylinder can be automatically judged according to different actual working conditions to determine whether it has recovery value, and the corresponding speed is fast, and the recovery process is intelligent and efficient.

[0044] It should be noted that in the process of potential energy recovery, fine operation of the load often requires the system to have good micro-motion performance. When the lifting cylinder is micro-moved downward, the descending speed is slow, and the control accuracy of the speed is high. Since the generator has poor control accuracy at low speed and low power generation efficiency, it is not suitable for potential energy recovery. The energy recovery system composed of a hydraulic motor, a generator and an energy storage device itself has certain energy loss. The energy storage device here can be a device for storing generator power. When the energy that can be recovered by the external load and the self-weight is less than the loss generated by the energy recovery system itself, the potential energy recovery will generate additional energy loss. Therefore, the potential energy recovery should have a certain requirement for the minimum value of the load.

[0045] Please refer to Figure 1 .

[0046] The embodiment discloses a potential energy recovery system with segmented speed regulation function, comprising:

[0047] The lifting cylinder 13 has a rod cavity connected to the oil tank 1, and a rodless cavity provided with a first pressure sensor 14 for detecting the pressure of the rodless cavity;

[0048] The oil supply module is provided with an oil tank 1 and an oil supply assembly for supplying oil to the potential energy recovery system;

[0049] The valve control module is connected between the oil supply module and the rodless cavity of the lifting cylinder 13, and is used to reduce the pressure of the pressure oil provided by the oil supply assembly and control the reversing of the pressure oil;

[0050] An energy recovery module is connected to the rodless cavity of the lifting oil cylinder 13 and is provided with a shunt assembly and a potential energy recovery device, the shunt assembly being used to shunt the pressure oil flowing through the energy recovery module;

[0051] A controller is used to receive the pressure value measured by the first pressure sensor 14 and select to open the valve control module or the energy recovery module according to the pressure value measured by the first pressure sensor 14 and a preset minimum pressure value.

[0052] The oil supply module, the valve control module and the energy recovery module are all connected with the controller.

[0053] In the specific embodiment, when fine operation of the load is required, the system often needs to have good micro-motion performance. When the lifting oil cylinder 13 is in micro-motion descent, the control accuracy of the speed is required to be very high. Since the generator 19 has poor control accuracy and low power generation efficiency at low speed, it is not suitable for energy recovery. According to the specific working condition, the descending speed V is taken as a dividing point with V1, V≥V1 is set as fast lowering, and V

[0054] Wherein, A1 is the acting area of the rodless cavity of the lifting oil cylinder 13; K1 is a proportional coefficient, which is determined by the actual hydraulic system and the related mechanical structure.

[0055] In the process of using the potential energy recovery system with segmented speed regulation function provided by the specific embodiment, when the lifting oil cylinder 13 is ascending, the oil supply assembly in the oil supply module is used to extract oil from the oil tank 1 and supply oil to the valve control module. The valve control module reduces the pressure of the pressure oil supplied by the oil supply assembly and supplies the pressure oil to the energy recovery module. The valve control module is in communication with the rodless cavity of the lifting oil cylinder 13, so that the pressure oil after pressure reduction enters the rodless cavity of the lifting oil cylinder 13 through the valve control module, the pressure in the rodless cavity of the lifting oil cylinder 13 is increased, and the lifting oil cylinder 13 is driven to ascend. When the lifting oil cylinder 13 ascends to a preset height, the valve control module stops supplying oil to the rodless cavity of the lifting oil cylinder 13, so that the lifting oil cylinder 13 keeps the preset height.

[0056] When the lifting oil cylinder 13 needs to descend, the valve control module or the energy recovery module can be selected to be opened according to actual needs.

[0057] When the lifting oil cylinder 13 needs to be slowly lowered, and the pressure of the rodless cavity of the lifting oil cylinder 13 is less than the preset minimum pressure value, at this time, the potential energy recovery value is not possessed, the valve control module can be opened, the throttling descending mode is adopted, and energy recovery is not performed; the pressure oil in the rodless cavity of the lifting oil cylinder 13 flows to the valve control module, and is returned to the oil tank 1 through the valve control module, and after the lifting oil cylinder 13 is lowered by a distance, the related valve bodies in the valve control module can be controlled to move to a position for preventing the pressure oil from continuing to flow into the oil tank 1, so that the lifting oil cylinder 13 is kept at the required height; in this process, the descending speed of the lifting oil cylinder 13 can be controlled through the valve control module, which is suitable for the case that the descending speed of the lifting oil cylinder 13 is slow and the control precision of the descending speed is high, and can effectively improve the control of the descending precision of the lifting oil cylinder 13.

[0058] When the lifting oil cylinder 13 is lowered, and the pressure of the rodless cavity of the lifting oil cylinder 13 is greater than or equal to the preset minimum pressure value, and the descending speed of the lifting oil cylinder 13 is less than or equal to the preset speed, the energy recovery module is opened, the pressure oil in the rodless cavity of the lifting oil cylinder 13 returns to the oil tank 1 through the shunt assembly, when the lifting oil cylinder 13 is lowered, and the pressure of the rodless cavity of the lifting oil cylinder 13 is greater than the preset minimum pressure value, and the descending speed of the lifting oil cylinder 13 is greater than the preset speed, the pressure oil sequentially flows through the shunt assembly and the potential energy recovery equipment through the shunt assembly to recover the potential energy of the pressure oil.

[0059] It needs to be noted that the number of the lifting oil cylinder 13 in the specific embodiment can be one, two or more, which is determined according to actual conditions. When the lifting oil cylinder 13 is multiple, the multiple lifting oil cylinders 13 are generally arranged in parallel.

[0060] Compared with the prior art, the potential energy recovery system with the segmented speed regulation function provided in the specific embodiment avoids the setting of the speed limiting valve in the traditional hydraulic system, reduces the throttling loss, adopts the variable speed volume speed regulation mode for energy recovery, reduces the energy loss caused by system heating, and has good energy saving effect. In the slow descending process, the valve control module is used to control the descending speed, and the control precision of the descending speed of the lifting oil cylinder 13 is improved; and in the use process, whether the descending process of the lifting oil cylinder 13 has the recovery value can be automatically judged according to different actual working conditions, the speed is correspondingly fast, and the recovery process is intelligent and efficient.

[0061] In a specific embodiment, the shunt assembly includes a recovery switching valve 15, a shunt valve 16 and an electromagnetic reversing valve 17; the oil inlet of the recovery switching valve 15 is connected with the rodless cavity of the lifting oil cylinder 13, the oil outlet of the recovery switching valve 15 is connected with the oil inlet of the shunt valve 16, one oil outlet of the shunt valve 16 is connected with the oil inlet of the electromagnetic reversing valve 17, and the other oil outlet of the shunt valve 16 is connected with the potential energy recovery equipment; the oil outlet of the electromagnetic reversing valve 17 is connected with the oil tank 1; the recovery switching valve 15 and the electromagnetic reversing valve 17 are connected with the controller.

[0062] The potential energy recovery device includes a hydraulic motor 20 and a generator 19 driven by the hydraulic motor 20;

[0063] The oil outlet of the diverter valve 16 and the oil outlet of the electromagnetic reversing valve 17 are both connected to the oil inlet of the hydraulic motor 20, and the oil outlet of the hydraulic motor 20 is connected to the oil tank 1;

[0064] The generator 19 is connected to the controller.

[0065] The oil inlet of the hydraulic motor 20 is provided with a second pressure sensor 18, which is used to detect the pressure of the oil inlet of the hydraulic motor 20;

[0066] The second pressure sensor 18 is connected to the controller.

[0067] Preferably, the diverter valve 16 is a three-way flow regulating valve, the oil inlet of the three-way flow regulating valve is connected to the rodless chamber of the lifting cylinder 13, the first oil outlet of the three-way flow regulating valve is connected to the electromagnetic reversing valve 17, and the second oil outlet of the three-way flow regulating valve is connected to the potential energy recovery device; and a damping hole is provided between the oil inlet and the first oil outlet of the three-way flow regulating valve, the oil inlet of the three-way flow regulating valve is connected to the springless side of the three-way flow regulating valve through a pipeline, and the first oil outlet is connected to the spring side of the three-way flow regulating valve through a pipeline. After the pressure oil flows into the oil inlet of the three-way flow regulating valve, it first flows to the first oil outlet. When the flow rate per unit time reaches the preset flow rate, the pressure difference ΔP across the fixed damping hole between the oil inlet and the first oil outlet of the three-way flow regulating valve remains basically constant. According to the load-sensitive working principle, the maximum value Q2 of the flow rate flowing out of the first oil outlet is:

[0068] Among them, K2 is the proportional coefficient and A2 is the effective area of ​​the damping hole.

[0069] When the flow rate flowing into the three-way flow control valve's oil inlet (PP port) is less than the maximum value Q2 of the flow rate flowing out of the first oil outlet (CF port), all the flow rate flows out of the first oil outlet, and the pressure oil flows through the first oil outlet and the solenoid reversing valve 17 in sequence and returns to the oil tank 1. When the flow rate flowing into the three-way flow control valve's oil inlet (PP port) is greater than the maximum value Q2 of the flow rate flowing out of the first oil outlet (CF port), a flow rate equal to the maximum value Q2 of the flow rate flows out of the first oil outlet, and the excess flow flows out of the second oil outlet (EF port). The maximum value of the controlled flow rate is designed to be Q2 = Q1. If the pressure detected by the second pressure sensor 18 is zero, it means that the entire descending flow rate flows out of the first oil outlet (CF port) of the diverter valve 16, and the pressure oil flows through the solenoid reversing valve 17 and enters the oil tank 1. If the pressure detected by second pressure sensor 18 is greater than zero, it indicates that excess flow is flowing out of the second oil outlet (port EF) of diverter valve 16. At this time, solenoid reversing valve 17 is energized and placed in the right position. The pressurized oil flowing out of the first oil outlet (port CF) of diverter valve 16 passes through solenoid reversing valve 17 and merges with the flow out of the second oil outlet (port EF) of diverter valve 16 to enter the inlet of hydraulic motor 20, causing hydraulic motor 20 to rotate, driving generator 19 to generate electricity, thereby achieving the purpose of potential energy recovery. The flow rate that decreases during the potential energy recovery process all flows into the motor, so the actual motor speed is positively correlated with the decrease rate.

[0070] In this process, Where V m is the displacement of hydraulic motor 20, η v is the volumetric efficiency of the hydraulic motor 20, Q1 is the drop flow rate generated by the drop corresponding to the speed V1, and n1 is the rotational speed of the generator 19.

[0071] When the speed of the generator 19 is less than n1, or when the pressure detected by the second pressure sensor 18 decreases to zero again, it means that the descending speed of the lifting cylinder 13 is less than V1, and the electromagnetic reversing valve 17 loses power and resets to the left end.

[0072] Preferably, the generator 19 is coaxially connected to the hydraulic motor 20, and the rotation speeds of the generator 19 and the hydraulic motor 20 are consistent. The hydraulic motor 20 can be set as a fixed-displacement motor. The generator 19 has a rotation speed sensor that can read the real-time rotation speed of the generator 19 in real time.

[0073] like Figure 1 As shown, the potential energy recovery device includes an oil replenishment one-way valve 21 arranged in parallel at the oil inlet and oil outlet of the hydraulic motor 20. When the hydraulic motor 20 is emptied, the pressure oil is replenished from the oil tank 1 to the hydraulic motor 20 through the oil replenishment one-way valve 21.

[0074] In the process of lowering the lifting cylinder 13, other resistance can be encountered, and under the action of resistance, the descending speed of the lifting cylinder 13 will decrease, and if the rotating speed of the hydraulic motor 20 is still the previous rotating speed, the oil inlet pressure of the hydraulic motor 20 will sharply decrease, and then the hydraulic motor 20 will appear the phenomenon of air suction. In order to prevent the hydraulic motor 20 from sucking air, the oil supplementing check valve 21 is connected in parallel at the oil inlet and outlet of the hydraulic motor 20, and when the phenomenon of air suction appears, the oil from the oil tank 1 can enter the oil inlet of the hydraulic motor 20, so as to avoid the sharp decrease of the oil inlet pressure of the hydraulic motor 20 and effectively avoid the phenomenon of air suction.

[0075] As shown in the figure, Figure 1 The recovery switching valve 15 is a two-position two-way electro-hydraulic proportional throttle valve, the oil inlet of the recovery switching valve 15 is connected with the rodless cavity of the lifting cylinder 13, the oil outlet of the recovery switching valve 15 is connected with the oil inlet of the hydraulic motor 20, and the valve control module provides the pilot oil with reduced pressure for the recovery switching valve 15;

[0076] In the process of use, the recovery switching valve 15 can adjust the opening of the valve core according to the size of the electric signal in the energized state, and when the recovery switching valve 15 is de-energized, the recovery switching valve 15 is located at the right position and the two ends are cut off, which can effectively prevent the pressure oil from flowing into the hydraulic motor 20.

[0077] Of course, the recovery switching valve 15 can also be other valve structures meeting the requirements, which will not be described here.

[0078] As shown in the figure, Figure 1 The oil supply assembly includes the motor 3, the variable pump 2 and the first check valve 4 arranged at the oil outlet of the variable pump 2, the first check valve 4 is connected with the valve control module, the motor 3 is connected with the variable pump 2 and drives the variable pump 2 to rotate.

[0079] Preferably, the motor 3 is coaxially connected with the variable pump 2, the motor 3 drives the variable pump 2 to work for oil supply, and the rotating speeds of the two are consistent. The variable pump has the load sensing function and can automatically adjust the displacement according to the required flow, so as to achieve the energy saving effect; the first check valve 4 is arranged at the oil outlet of the variable pump 2, which can effectively prevent the pressure oil from flowing back to the variable pump 2.

[0080] In a specific embodiment, the valve control module includes the pressure compensator 6, the pilot pressure reducing valve 12, the first electric proportional pressure reducing valve 8, the second electric proportional pressure reducing valve 9 and the throttle reversing valve 5, the pressure compensator 6 and the pilot pressure reducing valve 12 are connected with the oil supply assembly, the first electric proportional pressure reducing valve 8, the second electric proportional pressure reducing valve 9 and the energy recovery module are connected with the oil outlet of the pilot pressure reducing valve 12;

[0081] The working oil port of the first electric proportional pressure reducing valve 8 and the working oil port of the second electric proportional pressure reducing valve 9 are connected with the upper end and the lower end of the throttle reversing valve 5 respectively to drive the throttle reversing valve 5 to reverse, and the pressure compensator 6 is connected with the throttle reversing valve 5;

[0082] The first electric proportional pressure reducing valve and the second electric proportional pressure reducing valve are connected with the controller.

[0083] The output end of the pilot pressure reducing valve 12 is provided with the second check valve 11 and the accumulator 10, one end of the second check valve 11 is connected with the output end of the pilot pressure reducing valve 12, the other end is connected with the accumulator 10, and the first electric proportional pressure reducing valve 8 and the second electric proportional pressure reducing valve 9 are connected with the accumulator 10.

[0084] The overflow valve 7 connected with the throttle reversing valve 5 in parallel is further included, and the overflow valve 7 is used to limit the working oil port pressure of the throttle reversing valve 5.

[0085] In the case that the motor 3 does not rotate, the accumulator 10 can provide the first electric proportional pressure reducing valve 8 and the second electric proportional pressure reducing valve 9 with a pilot oil source to realize the lowering function of the lifting cylinder 13, and the setting of the second check valve 11 can effectively prevent the pressure oil in the accumulator 10 from flowing back to the pilot pressure reducing valve 12.

[0086] The setting of the overflow valve 7 can effectively limit the pressure of the working oil port of the throttle reversing valve 5, and when the oil pressure is greater than the preset value of the overflow valve 7, the pressure oil flows back to the oil tank 1 through the overflow valve 7.

[0087] In the process of use, the variable pump 2 provides the pilot pressure reducing valve 12 and the pressure compensator 6 with pressure oil, the pressure oil provided by the variable pump 2 enters the throttle reversing valve 5 through the pressure compensator 6, and the working oil port of the throttle reversing valve 5 is connected with the load holding valve. Further, the working oil port pressure of the throttle reversing valve 5 is introduced into the spring cavity side of the pressure compensator 6 through the pipeline, and the pressure oil at the oil outlet of the pressure compensator 6 is introduced into the spring-free cavity side of the pressure compensator 6 through the pipeline, thereby forming a load sensing system, so that the flow provided by the throttle reversing valve 5 is proportional to the displacement of the valve core, and the control accuracy of the flow is ensured.

[0088] The pressure oil provided by the variable pump 2 is reduced by the pilot pressure reducing valve 12 to provide the recovery switching valve 15, the first electric proportional pressure reducing valve 8 and the second electric proportional pressure reducing valve 9 with a pilot oil; the first electric proportional pressure reducing valve 8 and the second electric proportional pressure reducing valve 9 are pilot valves of the throttle reversing valve 5, and when the first electric proportional pressure reducing valve 8 is powered, the valve core of the throttle reversing valve 5 can be driven to move downward, and when the second electric proportional pressure reducing valve 9 is powered, the valve core of the throttle reversing valve 5 can be driven to move upward, and the displacement size is determined by the obtained electric signal (current or voltage).

[0089] As Figure 1As shown, the potential energy recovery system with segmented speed regulation function provided by the embodiment comprises an oil tank 1, a variable pump 2, an electric motor 3, a first check valve 4, a throttling reversing valve 5, a pressure compensator 6, an overflow valve 7, a first electric proportional pressure reducing valve 8, a second electric proportional pressure reducing valve 9, an accumulator 10, a second check valve 11, a pilot pressure reducing valve 12, a lifting oil cylinder 13, a first pressure sensor 14, a recovery switching valve 15, a shunt valve 16, an electromagnetic reversing valve 17, a second pressure sensor 18, a generator 19, a hydraulic motor 20, and an oil supplement check valve 21.

[0090] The specific connection relationship is as follows:

[0091] The motor 3 is coaxially connected with the variable pump 2 and has the same rotating speed. The first one-way valve 4 is installed at the oil outlet of the variable pump 2 to prevent the pressure oil in the system from flowing reversely into the variable pump 2. The pressure oil provided by the variable pump 2 is connected with the oil inlet of the pilot pressure reducing valve 12 and the oil inlet of the pressure compensator 6 through pipelines after passing through the first one-way valve 4. The pressure oil is communicated with the oil inlets of the first electric proportional pressure reducing valve 8, the second electric proportional pressure reducing valve 9 and the recovery switching valve 15 through pipelines after being reduced in pressure by the pilot pressure reducing valve 12 to provide the pilot pressure oil required for the action of the valves. The working oil outlets of the first electric proportional pressure reducing valve 8 and the second electric proportional pressure reducing valve 9 are connected with the upper end and the lower end of the throttle reversing valve 5 respectively to drive the throttle reversing valve 5 to move up and down. Meanwhile, the accumulator 10 and the second one-way valve 11 are arranged in the pilot oil pipeline provided by the pilot pressure reducing valve 12. The accumulator 10 is used to ensure that the lifting oil cylinder 13 can still be lowered when the motor 3 does not work if the lifting oil cylinder 13 needs to be lowered. The second one-way valve 11 is used to prevent the oil in the accumulator 10 from entering the pilot pressure reducing valve 12. The pressure compensator 6 is connected with the oil inlet of the throttle reversing valve 5 through a pipeline. The working oil outlet of the throttle reversing valve 5 is connected with the rodless chamber of the lifting oil cylinder 13 through a pipeline. Meanwhile, the outlet pressure of the pressure compensator 6 is introduced into the spring chamber side of the pressure compensator 6 through a pipeline, and the outlet pressure of the throttle reversing valve 5 is introduced into the spring chamber side of the pressure compensator 6, so as to form a load sensing system, so that the flow provided by the throttle reversing valve 5 is proportional to the displacement of the valve core, and the control accuracy of the flow is ensured. The overflow valve 7 is connected in parallel with the throttle reversing valve 5 and the lifting oil cylinder 13 to limit the maximum working pressure of the throttle reversing valve 5. The first pressure sensor 14 is connected in parallel with the rodless chamber of the lifting oil cylinder 13 at the bottom of the rodless chamber to monitor the pressure of the rodless chamber of the lifting oil cylinder 13. The water temperature of the rod chamber of the lifting oil cylinder 13 is connected with the oil tank 1 through a pipeline. The rodless chamber of the lifting oil cylinder 13 is connected with the oil inlet of the recovery switching valve 15 through a pipeline. The oil outlet of the recovery switching valve 15 is connected with the oil inlet (PP port) of the flow divider valve 16 through a pipeline. The flow divider valve 16 includes two outlets. The second oil outlet (EF port) is connected with the inlet of the hydraulic motor 20 through a pipeline. The first oil outlet (CF port) is connected with the oil inlet of the electromagnetic reversing valve 17 through a pipeline. The electromagnetic reversing valve 17 includes two oil outlets. One oil outlet is connected with the oil inlet of the hydraulic motor 20 through a pipeline. The other oil outlet is connected with the oil tank 1 through a pipeline. The generator 19 is coaxially connected with the hydraulic motor 20 and has the same rotating speed. The oil outlet of the hydraulic motor 20 is connected with the oil tank 1 through a pipeline. Meanwhile, the oil inlets and the oil outlets of the hydraulic motor 20 are connected in parallel on both sides of the oil tank 1 to prevent air suction.

[0092] The specific working mode is as follows:

[0093] When the lifting cylinder 13 needs to rise, the motor 3 drives the variable pump 2 to rotate, the variable pump 2 sucks oil from the oil tank 1, the pressure oil is reduced by the pilot relief valve 12 to provide the pilot oil for the first electric proportional relief valve 8, under the action of the control electric signal, the valve core of the first electric proportional relief valve 8 will produce corresponding displacement, the pilot oil is further reduced to act on the upper end of the throttling reversing valve 5, and the throttling reversing valve 5 is driven to move downward, so that the throttling reversing valve 5 works in the upper position. At this time, the pressure oil enters the rodless cavity of the lifting cylinder 13 through the first one-way valve 4, the pressure compensator 6 and the throttling reversing valve 5 in turn, and drives the lifting cylinder 13 to rise.

[0094] In the lifting process of the lifting cylinder 13, the rotating speed of the motor 3 can be set as a constant value, and the variable mechanism of the variable pump 2 is adjusted to realize the supply-demand matching of the flow. In this way, the product of the rotating speed of the motor 3 and the maximum displacement of the variable pump 2 is required to be greater than the flow required for lifting, and the lifting speed is determined by the opening of the valve core of the throttling reversing valve 5. The rotating speed of the motor 3 can also be adjusted to realize the supply-demand matching of the flow, that is, the product of the rotating speed of the motor 3 and the maximum displacement of the variable pump 2 is equal to the flow required for lifting. In this way, the throttling reversing valve 5 can be fully opened, and the rotating speed of the motor 3 is adjusted to control the lifting speed.

[0095] When the lifting cylinder 13 rises to a certain position and needs to be kept, the controller controls the first electric proportional relief valve 8 to be powered off and reset to the lower position, and the upper end of the throttling reversing valve 5 loses pressure and is reset to the middle position under the action of its own spring. The throttling reversing valve 5 no longer supplies oil, and the lifting cylinder 13 remains stationary.

[0096] When the lifting cylinder 13 needs to descend, if P≤P min , the pressure in the rodless cavity of the lifting cylinder 13 is less than the preset minimum pressure value, indicating that it has no recycling value at this time. Under the action of the control electric signal, the valve core of the second electric proportional relief valve 9 will produce corresponding displacement, the pilot oil acts on the lower end of the throttling reversing valve 5, and the throttling reversing valve 5 is driven to move upward, so that the throttling reversing valve 5 works in the lower position. At this time, the pressure oil in the rodless cavity of the lifting cylinder 13 enters the oil tank 1 through the throttling reversing valve 5, and the lifting cylinder 13 descends. If P≥P min, the pressure of the rodless cavity of the lifting oil cylinder 13 is greater than or equal to a preset minimum pressure value, when slow lowering is needed, under the action of the control electric signal, the energy recovery module is started, the pressure oil of the rodless cavity of the lifting oil cylinder 13 flows back to the oil tank 1 through the recovery switching valve 15, the first oil outlet (CF port) of the flow dividing valve 16 and the electromagnetic reversing valve 17 in turn. When the lowering speed gradually increases to V1, the pressure oil of the second oil outlet (EF port) of the flow dividing valve 16 enters the oil inlet of the hydraulic motor 20, and the second pressure sensor 18 detects the pressure, at this time the electromagnetic reversing valve 17 is electrified and works at the right position. The pressure oil of the rodless cavity of the lifting oil cylinder 13 flows into the hydraulic motor 20 through the recovery switching valve 15, the flow dividing valve 16 and the electromagnetic reversing valve 17 in turn, drives the hydraulic motor 20 to rotate to generate electricity, and flows back to the oil tank 1 through the oil outlet of the hydraulic motor 20. When the lowering speed is less than V1 again, the rotating speed of the generator 19 will be less than n1, at this time the electromagnetic reversing valve 17 is de-energized and works at the left position. When the lifting oil cylinder 13 is lowered by a certain distance and needs to be kept at a certain position, the recovery switching valve 15 is de-energized and works at the right position, and the electromagnetic reversing valve 17 is de-energized and works at the left position, so that the pressure oil of the rodless cavity of the lifting oil cylinder 13 cannot flow out, and the position is kept fixed.

[0097] The energy recovery module composed of the hydraulic motor 20, the generator 19 and the energy storage device also has certain loss, when the energy that can be recovered by the load is less than the loss generated by the system itself, the potential energy recovery will cause additional energy loss. Therefore, the potential energy recovery has a minimum load requirement for the load, which corresponds to the rodless cavity pressure P in the present application, that is, P>Pmin, wherein the rodless cavity pressure P is measured by the first pressure sensor 14. When slow lowering is needed, the control accuracy of the speed is required to be high, the generator 19 is usually in a low rotation state, and the system recovery efficiency will be low, at this time the potential energy recovery is not suitable.

[0098] During the slow lowering process, the recovery switching valve 15 is partially opened according to the size of the electric signal, the lowering flow flows back to the oil tank 1 through the recovery switching valve 15 and the first oil outlet (CF port) of the flow dividing valve 16, the lowering speed is determined by the opening of the recovery switching valve 15, and the control accuracy is high by using valve control. When fast lowering is needed, the control accuracy of the speed is not required to be high, the valve core of the recovery switching valve 15 is fully opened to reduce the throttling loss, the lowering flow enters the hydraulic motor 20 for potential energy recovery, the lowering speed is determined by the rotating speed of the generator 19, the recovery efficiency is high, and the energy saving effect is good. Therefore, by relying on the cooperation of the first pressure sensor 14, the second pressure sensor 18 and the characteristics of the flow dividing valve 16, it can be automatically judged whether the lowering process has recovery value according to the actual working condition, and the recovery process is intelligent and efficient.

[0099] When the lifting oil cylinder 13 needs to rise, the motor 3 drives the variable pump 2 to rotate, the first electric proportional pressure reducing valve 8 is powered on, the pilot oil acts on the upper end of the throttling reversing valve 5 after pressure reduction, drives the throttling reversing valve 5 to move down, so that the throttling reversing valve 5 works in the upper position. At this time, the oil liquid passes through the variable pump 2, the first one-way valve 4, the pressure compensator 6, the throttling reversing valve 5 in turn, enters the rodless cavity of the lifting oil cylinder 13, and drives the lifting oil cylinder 13 to rise. If the control accuracy of the speed is high, the fixed speed mode of the motor 3 can be used, if the control accuracy of the speed is not high, the variable speed mode of the motor 3 can be used to reduce the throttling loss.

[0100] The "first" and "second" in the first electric proportional pressure reducing valve 8 and the second electric proportional pressure reducing valve 9, the first one-way valve 4 and the second one-way valve 11 mentioned in the application file are only to distinguish the difference of position, and there is no difference in sequence.

[0101] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same and similar parts between various embodiments can be referred to each other. Any combination of all the embodiments provided by the application is within the protection scope of the application, which is not described here.

[0102] The above has carried out the detailed introduction to the potential energy recovery system with segmented speed regulation function provided by the application. The principle and implementation mode of the application are described by applying specific examples in this paper. The above embodiment description is only used to help understand the method of the application and its core idea. It should be pointed out that for ordinary skilled person in the art, without departing from the principle of the application, the application can be improved and modified in several ways, and these improvements and modifications also fall within the protection scope of the claims of the application.

Claims

1. A potential energy recovery system with segmented speed regulation function, characterized in that: include: A lifting oil cylinder (13), wherein the rod chamber thereof is connected to the oil tank (1), and the rodless chamber thereof is provided with a first pressure sensor (14) for detecting the pressure of the rodless chamber; An oil supply module is provided with an oil tank (1) and an oil supply assembly, wherein the oil supply assembly is used to supply oil to the potential energy recovery system; a valve control module connected between the oil supply module and the rodless chamber of the lifting oil cylinder (13) and used to reduce the pressure of the pressure oil provided by the oil supply assembly and control the reversal of the pressure oil; An energy recovery module, which is connected to the rodless chamber of the lifting oil cylinder (13) and is provided with a diversion component and a potential energy recovery device, wherein the diversion component is used to divert the pressure oil flowing through the energy recovery module; A controller, configured to receive the pressure value measured by the first pressure sensor (14), and select to open the valve control module or the energy recovery module according to the pressure value measured by the first pressure sensor (14) and a preset minimum pressure value; The oil supply module, the valve control module and the energy recovery module are all connected to the controller; The valve control module comprises a pressure compensator (6), a pilot pressure reducing valve (12), a first electric proportional pressure reducing valve (8), a second electric proportional pressure reducing valve (9) and a throttle reversing valve (5); the pressure compensator (6) and the pilot pressure reducing valve (12) are both connected to the oil supply assembly; the first electric proportional pressure reducing valve (8), the second electric proportional pressure reducing valve (9) and the energy recovery module are all connected to the oil outlet of the pilot pressure reducing valve (12); The working oil port of the first electric proportional pressure reducing valve (8) and the working oil port of the second electric proportional pressure reducing valve (9) are respectively connected to the upper end and the lower end of the throttle reversing valve (5) to drive the throttle reversing valve (5) to reverse, and the pressure compensator (6) is connected to the throttle reversing valve (5); The first electric proportional pressurizing valve and the second electric proportional pressurizing valve are both connected to the controller; The diversion assembly includes a recovery switching valve (15), a diversion valve (16), and an electromagnetic reversing valve (17); The oil inlet of the recovery switching valve (15) is connected to the rodless chamber of the lifting cylinder (13), the oil outlet of the recovery switching valve (15) is connected to the oil inlet of the diverter valve (16), one oil outlet of the diverter valve (16) is connected to the oil inlet of the electromagnetic reversing valve (17), and the other oil outlet of the diverter valve (16) is connected to the potential energy recovery device; the oil outlet of the electromagnetic reversing valve (17) is connected to the oil tank (1); The recovery switching valve (15) and the electromagnetic reversing valve (17) are both connected to the controller.

2. The potential energy recovery system with segmented speed regulation function according to claim 1 is characterized in that: The diverter valve (16) is a three-way flow regulating valve, the oil inlet of the three-way flow regulating valve is connected to the rodless chamber of the lifting cylinder (13), the first oil outlet of the three-way flow regulating valve is connected to the electromagnetic reversing valve (17), and the second oil outlet of the three-way flow regulating valve is connected to the potential energy recovery device; A damping hole is provided between the oil inlet of the three-way flow regulating valve and the first oil outlet, the oil inlet of the three-way flow regulating valve is connected to the non-spring side of the three-way flow regulating valve, and the first oil outlet is connected to the spring side of the three-way flow regulating valve.

3. The potential energy recovery system with segmented speed regulation function according to claim 1 is characterized in that: The potential energy recovery device includes a hydraulic motor (20) and a generator (19) driven to rotate by the hydraulic motor (20); The oil outlet of the diverter valve (16) and the oil outlet of the electromagnetic reversing valve (17) are both connected to the oil inlet of the hydraulic motor (20), and the oil outlet of the hydraulic motor (20) is connected to the oil tank (1); The generator (19) is connected to the controller.

4. The potential energy recovery system with segmented speed regulation function according to claim 3 is characterized in that: The potential energy recovery device comprises an oil replenishment one-way valve (21) arranged in parallel at the oil inlet and the oil outlet of the hydraulic motor (20). When the hydraulic motor (20) is emptied, pressure oil is replenished from the oil tank (1) to the hydraulic motor (20) via the oil replenishment one-way valve (21).

5. The potential energy recovery system with segmented speed regulation function according to claim 3 is characterized in that: The oil inlet of the hydraulic motor (20) is provided with a second pressure sensor (18), and the second pressure sensor (18) is used to detect the pressure of the oil inlet of the hydraulic motor (20); The second pressure sensor (18) is connected to the controller.

6. The potential energy recovery system with segmented speed regulation function according to claim 1, characterized in that: The oil supply assembly comprises an electric motor (3), a variable displacement pump (2), and a first one-way valve (4) arranged at the oil outlet of the variable displacement pump (2), wherein the first one-way valve (4) is connected to the valve control module, and the electric motor (3) is connected to the variable displacement pump (2) and drives the variable displacement pump (2) to rotate; The electric motor (3) is connected to the controller.

7. The potential energy recovery system with segmented speed regulation function according to claim 1 is characterized in that: The output end of the pilot pressure reducing valve (12) is provided with a second one-way valve (11) and an accumulator (10); one end of the second one-way valve (11) is connected to the output end of the pilot pressure reducing valve (12), and the other end is connected to the accumulator (10); the first electric proportional pressure reducing valve (8) and the second electric proportional pressure reducing valve (9) are both connected to the accumulator (10).

8. The potential energy recovery system with segmented speed regulation function according to claim 7, characterized in that: It also includes a relief valve (7) connected in parallel with the throttle reversing valve (5), and the relief valve (7) is used to limit the working oil port pressure of the throttle reversing valve (5).

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