System and method for recycling die opening and closing kinetic energy of die-casting machine

Abstract

The invention relates to the technical field of hydraulic transmission, in particular to a die opening and closing kinetic energy recovery system and method for a die-casting machine. The system comprises a mold opening and closing hydraulic cylinder, a main oil pump, a reversing valve group, a mixed energy recovery unit and a measurement and control unit, and the mixed energy recovery unit comprises a pocket peak hydraulic energy storage passage and a speed control electric side energy storage passage. And the control unit is used for switching a pocket peak hydraulic energy storage passage and a speed control electric side energy storage passage according to operation data of the mold opening and closing hydraulic cylinder and the mixed energy recovery unit. Meanwhile, the invention discloses a recovery method based on the system, by adopting the die-casting machine opening and closing die kinetic energy recovery system and the recovery method, energy recovery is carried out through coupling cooperation of a pocket peak hydraulic energy storage channel and a speed control electric side energy storage channel, an energy accumulator carries out pocket peak in advance, a super capacitor carries out time sequence connection, and the energy storage channel carries out energy recovery. The movement speed of the mold opening and closing hydraulic cylinder is rapidly increased, the rated power of a main pump is reduced, flexible stopping of high-precision speed control is achieved, and impact on equipment during stopping at a stroke terminal is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic transmission, in particular to a die casting machine mold opening and closing kinetic energy recovery system and recovery method. BACKGROUND

[0002] The die casting machine is mainly driven by a constant-speed motor and a quantitative pump, and some new models use a servo motor + variable pump (or built-in servo pump) to reduce standby loss. The energy flow of the die casting machine mold opening and closing system presents the characteristics of "large instantaneous flow, frequent acceleration and deceleration, high peak power and low average power". At the same time, there is a lot of throttling dissipation in the terminal deceleration and low speed section, which leads to oil temperature rise, cooling load increase, valve impact and noise problem. In the prior art, energy accumulators are used for energy recovery, and gas bag type accumulators are arranged in the mold opening and closing or injection circuit, for example, the application publication No. CN113357234A discloses a digital control based accumulator group engineering machinery rotary device energy recovery system, which realizes the adaptation of the system to different working conditions by arranging multiple accumulators, so that the system achieves a better energy recovery efficiency and utilization efficiency under different loads. Although the application of the accumulator realizes energy recovery, the single recovery path cannot realize precise speed control, and it is difficult to realize the consistency of programmable speed curve and position of terminal deceleration only by the accumulator, and the accumulator is limited by pressure window and gas variability. SUMMARY

[0003] The purpose of the present application is to provide a die casting machine mold opening and closing kinetic energy recovery system and recovery method to solve the above technical problems.

[0004] To achieve the above purpose, the present application provides a die casting machine mold opening and closing kinetic energy recovery system, which comprises a mold opening and closing hydraulic cylinder, a main oil pump, a first reversing valve and a second reversing valve. The mold opening and closing hydraulic cylinder has a rodless cavity and a rod cavity. The first reversing valve is arranged on a first passage between the main oil pump and the rodless cavity. The second reversing valve is arranged on a second passage between the first reversing valve and the rod cavity. The system further comprises a mixed energy recovery unit and a control unit. The mixed energy recovery unit comprises a peak-holding hydraulic energy storage passage and a speed control electric side energy storage passage. The connection point of the peak-holding hydraulic energy storage passage and the speed control electric side energy storage passage is connected with a deceleration passage. The first reversing valve and the second reversing valve are both arranged on the deceleration passage. The connection point of the peak-holding hydraulic energy storage passage and the speed control electric side energy storage passage is connected with one end of an acceleration passage. The other end of the acceleration passage is connected with the first passage between the first reversing valve and the main oil pump. The acceleration passage is provided with a third reversing valve in parallel, which is used to control the opening and closing of a cartridge valve on the acceleration passage. The control unit is used to collect the operation data of the mold opening and closing hydraulic cylinder and the mixed energy recovery unit, and to switch the peak-holding hydraulic energy storage passage and the speed control electric side energy storage passage according to the operation data.

[0005] Preferably, at least one accumulator and a first control valve are arranged on the hydraulic energy storage passage of the peak pocket, the first control valve is used for controlling the oil return direct charging and energy release of the accumulator, a safety passage is connected between the accumulator and the first control valve, and a safety valve is arranged at the tail end of the safety passage and used for limiting the maximum pressure of the accumulator.

[0006] Preferably, a hydraulic motor / pump integrated machine and a second control valve are arranged on the speed control electric side energy storage passage, a bidirectional three-phase active rectifier module is connected to the hydraulic motor / pump integrated machine, a filter is connected to the bidirectional three-phase active rectifier module, a first DC-DC conversion module is connected to the filter, the first DC-DC conversion module and the filter are connected to a high-voltage contactor, the high-voltage contactor is connected to a super capacitor group and is provided with a brake resistor module, and the super capacitor group is connected to the bidirectional three-phase active rectifier module through a second DC-DC conversion module.

[0007] Preferably, the super capacitor group is provided with a super capacitor management module, the super capacitor management module is used for voltage balancing, temperature monitoring and health state monitoring and evaluation of the super capacitor group, the super capacitor group is connected to a DC bus, and the DC bus is connected to an energy interface of a power consumption device to realize energy sharing.

[0008] Preferably, the deceleration channel and the acceleration passage are both provided with check valves or shuttle valves for preventing the electro-hydraulic passage from being backfilled.

[0009] Preferably, the first passage, the deceleration channel and the acceleration passage are all connected to overflow valves.

[0010] Preferably, the measurement and control unit comprises a pressure acquisition module, an electric parameter acquisition module, an open-close die parameter acquisition module, a temperature acquisition module and a control module; the pressure acquisition module, the electric parameter acquisition module, the open-close die parameter acquisition module and the temperature acquisition module are all connected to the control module and used for controlling the state of corresponding components according to the collected data; The pressure acquisition module is used for collecting the pressure of the accumulator. The electric parameter acquisition module is used for collecting the voltage of the DC bus. The open-close die parameter acquisition module is used for collecting the displacement and speed of the open-close die. The temperature acquisition module is used for collecting the oil temperature and the environmental temperature and is used for temperature compensation of the subsequent accumulator pressure value. In the energy recovery stage, the peak pocket hydraulic energy storage passage is preferentially opened to charge the oil return directly to the accumulator; when the moving die reaches a preset displacement or speed and the deceleration control with a set accuracy is required, the speed control electric side energy storage passage is switched on to drive the hydraulic motor / pump integrated machine with the oil return, and the converted electric energy is stored in the super capacitor group. The first control valve is preferentially opened in the energy releasing stage to make the accumulator release energy to the mold opening and closing hydraulic cylinder to provide peak flow; when the accumulator pressure drops to a lower threshold, the speed control electric side energy storage passage is driven by the inverse variable drive hydraulic motor / pump integrated machine to supplement power as a pump; Soft switching and power distribution are implemented according to the accumulator pressure window and the DC bus voltage window; When the DC bus is overvoltage and the first DC-DC conversion module has limited power, the brake resistance module is put into operation to protect the super capacitor group.

[0011] Based on the above-mentioned recovery method of the die casting machine mold opening and closing kinetic energy recovery system, the specific steps are as follows: Step S1: According to the speed-time curve of the die casting machine, the mold opening and closing cycle is divided into working conditions; Step S2: According to the working condition division, the switching strategy is set; Step S3: According to the switching strategy and the collected operation data, the switching of the peak-holding hydraulic energy storage passage and the speed control electric side energy storage passage is carried out to realize energy recovery in different working conditions.

[0012] Preferably, the mold opening and closing cycle is divided into six working conditions, which are high-speed mold closing T1, low-speed mold closing T2, mold closing T3, low-speed mold opening T4, high-speed mold opening T5 and mold opening T6; the mold opening includes a high-speed to low-speed transition section T6-1 and a mold opening terminal deceleration section T6-2.

[0013] Preferably, during the low-speed mold closing T2 and high-speed to low-speed transition section T6-1 stages, the oil return preferentially enters the accumulator in the peak-holding hydraulic energy storage passage through the deceleration channel to form a back pressure state; when the moving die reaches a preset speed or displacement and needs to set the precision deceleration control, the speed control electric side energy storage passage is switched, and the energy is converted into electrical energy by the hydraulic motor / pump integrated machine and stored in the super capacitor group; During the mold closing T3, low-speed mold opening T4 and mold opening terminal deceleration section T6-2 stages, the oil return preferentially enters the switched speed control electric side energy storage passage through the deceleration channel, and the hydraulic motor / pump integrated machine is closed loop tracked according to the electromagnetic torque to realize the speed control and energy recovery of the moving die speed curve; During the high-speed mold closing T1 and high-speed mold opening T5 stages, the accumulator releases energy to hold the peak, and a high-speed running state is established; when the accumulator pressure drops to a lower limit, the speed control electric side energy storage passage is switched, and the hydraulic motor / pump integrated machine is driven by the super capacitor group to supplement energy; Soft switching and power distribution are implemented according to the accumulator pressure window and the DC bus voltage window; when the bus voltage exceeds the first threshold, the power is limited; when the threshold is still exceeded, the brake resistance module is put into operation to absorb excess energy; Before shutdown or maintenance, the first control valve and the second control valve enter a safe working condition, and the super capacitor group temperature is in a set temperature range, so that the residual energy of the accumulator is converted by the hydraulic motor / pump integrated machine and stored in the super capacitor group, and the high-voltage contactor is disconnected to make the DC bus power off, and when the super capacitor group temperature is not in the set temperature range, the brake resistor module is used for energy release.

[0014] Therefore, the die casting machine mold opening and closing kinetic energy recovery system and the recovery method have the beneficial effects that: (1) The mixed energy recovery unit includes a peak-holding hydraulic energy storage path and a speed control electric side energy storage path, and energy recovery is performed through coupling and cooperation of the peak-holding hydraulic energy storage path and the speed control electric side energy storage path, the accumulator first holds the peak, and the super capacitor sequentially receives, so that the movement speed of the mold opening and closing hydraulic cylinder is quickly improved, the rated power of the main pump is reduced, and flexible parking with high-precision speed control is realized, and the impact on the equipment when parking at the end of the stroke is reduced.

[0015] (2) The measurement and control unit switches the peak-holding hydraulic energy storage path and the speed control electric side energy storage path through the running data of the mold opening and closing hydraulic cylinder and the mixed energy recovery unit, i.e. threshold soft switching and power distribution are performed according to the accumulator pressure window and the DC bus voltage window, the electric side programmable speed control + accumulator back pressure cooperative control covering six working conditions is formed, and the safety and stability of switching are ensured through threshold soft switching and valve hard interlocking, while meeting the V-T curve speed and forming process requirements, the rated power of the main pump, overflow and cooling loss are significantly reduced.

[0016] The technical solutions of the present application will be further described in detail below with the aid of the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a schematic diagram of a die casting machine mold opening and closing kinetic energy recovery system. Figure 2 It is a mold opening and closing cycle speed-time curve diagram. Figure 3 It is a high-speed mold closing T1 stage oil circuit schematic diagram. Figure 4 It is a low-speed mold closing T2 stage oil circuit schematic diagram. Figure 5 It is a mold closing T3 stage oil circuit schematic diagram. Figure 6 It is a low-speed mold opening T4 stage oil circuit schematic diagram. Figure 7 It is a high-speed mold opening T5 stage oil circuit schematic diagram. Figure 8 It is a mold opening T6 stage oil circuit schematic diagram. Figure 9The oil circuit diagram for parking or maintenance.

[0018] Reference numerals 1, opening and closing mold hydraulic cylinder; 11, rodless cavity; 12, rod cavity; 2, main oil pump; 3, first directional valve; 4, second directional valve; 5, first passage; 6, second passage; 7, hybrid energy recovery unit; 71, surge hydraulic energy storage passage; 711, accumulator; 712, first control valve; 713, safety passage; 714, safety valve; 72, speed control electric side energy storage passage; 721, hydraulic motor / pump integrated machine; 722, second control valve; 723, bidirectional three-phase active rectifier module; 724, filter; 725, first DC-DC conversion module; 726, high-voltage contactor; 727, brake resistance module; 728, second DC-DC conversion module; 729, super capacitor group; 7291, super capacitor management module; 73, speed reduction passage; 74, speed up passage; 741, third directional valve; 742, cartridge valve; 75, check valve; 8, overflow valve. DETAILED DESCRIPTION

[0019] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product of the present application is used, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "arrangement", "installation", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0020] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0021] As Figure 1As shown, a die casting machine opening and closing mold kinetic energy recovery system, including opening and closing mold hydraulic cylinder 1, main oil pump 2, first reversing valve 3 and second reversing valve 4, opening and closing mold hydraulic cylinder 1 has no rod cavity 11 and rod cavity 12, the first reversing valve 3 is arranged on the first passage 5 between the main oil pump 2 and the no rod cavity 11, the second reversing valve 4 is arranged on the second passage 6 between the first reversing valve 3 and the rod cavity 12, further comprising a mixed energy recovery unit 7 and a measurement and control unit, the mixed energy recovery unit 7 comprises a peak-holding hydraulic energy storage passage 71 and a speed control electric side energy storage passage 72, the connection point of the peak-holding hydraulic energy storage passage 71 and the speed control electric side energy storage passage 72 is connected with a speed reduction channel 73, and the first reversing valve 3 and the second reversing valve 4 are arranged on the speed reduction channel 73; the connection point of the peak-holding hydraulic energy storage passage 71 and the speed control electric side energy storage passage 72 is connected with one end of a speed-up passage 74, the other end of the speed-up passage 74 is connected on the first passage 5 between the first reversing valve 3 and the main oil pump 2, and the speed-up passage 74 is provided with a third reversing valve 741 in parallel, for controlling the opening and closing of a cartridge valve 742 on the speed-up passage 74. The speed reduction channel 73 and the speed-up passage 74 are both provided with a check valve 75 for preventing the mutual backflow of electro-hydraulic passages.

[0022] A accumulator 711 and a first control valve 712 are arranged on the peak-holding hydraulic energy storage passage 71, the first control valve 712 is used for controlling the oil return direct filling and energy release of the accumulator 711, a safety passage 713 is connected between the accumulator 711 and the first control valve 712 on the peak-holding hydraulic energy storage passage 71, and a safety valve 714 is arranged at the tail end of the safety passage 713, for limiting the maximum pressure of the accumulator 711.

[0023] A hydraulic motor / pump integrated machine 721 and a second control valve 722 are arranged on the speed control electric side energy storage passage 72, the hydraulic motor / pump integrated machine 721 is connected with a bidirectional three-phase active rectifier module 723, the bidirectional three-phase active rectifier module 723 is connected with a filter 724, the filter 724 is connected with a first DC-DC conversion module 725, the first DC-DC conversion module 725 and the filter 724 are both connected with a high-voltage contactor 726, the high-voltage contactor 726 is connected with a super capacitor group 729 and is provided with a brake resistor module 727, the super capacitor group 729 is connected with the bidirectional three-phase active rectifier module 723 through a second DC-DC conversion module 728. The super capacitor group 729 is provided with a super capacitor management module 7291, which is used for voltage equalization, temperature monitoring and health state monitoring and evaluation of the super capacitor group 729, the super capacitor group 729 is connected with a DC bus, and the DC bus is connected with an energy interface of an energy consumption device to realize energy sharing.

[0024] The first passage 5, the speed reduction channel 73 and the speed-up passage 74 are all connected with an overflow valve 8.

[0025] The control unit is used to collect the operating data of the mold opening and closing hydraulic cylinder 1 and the hybrid energy recovery unit 7, and to switch the peak hydraulic energy storage path 71 and the speed control electric side energy storage path 72 according to the operating data.

[0026] The measurement and control unit includes a pressure acquisition module, an electrical parameter acquisition module, a mold opening and closing parameter acquisition module, a temperature acquisition module, and a control module. The pressure acquisition module, electrical parameter acquisition module, mold opening and closing parameter acquisition module, and temperature acquisition module are all connected to the control module and are used to control the state of the corresponding components based on the acquired data.

[0027] The pressure acquisition module is used to acquire the pressure of accumulator 711.

[0028] The electrical parameter acquisition module is used to acquire the voltage of the DC bus.

[0029] The mold opening and closing parameter acquisition module is used to acquire the displacement and velocity of the mold opening and closing.

[0030] The temperature acquisition module is used to collect oil temperature and ambient temperature, which is used for temperature compensation of the pressure value of the accumulator 711.

[0031] During the energy recovery phase, the peak hydraulic energy storage passage 71 is opened first, so that the return oil is directly charged to the accumulator 711; when the moving mold reaches the preset displacement or speed and requires precise deceleration control, the speed control electric side energy storage passage 72 is switched on, so that the return oil drives the hydraulic motor / pump integrated machine 721, and the converted electrical energy is stored in the supercapacitor group 729.

[0032] During the energy release phase, the first control valve 712 is opened first to allow the accumulator 711 to release energy to the opening and closing hydraulic cylinder 1 to provide peak flow. When the pressure of the accumulator 711 drops to the lower threshold, the speed control electric side energy storage passage 72 drives the hydraulic motor / pump integrated machine 721 via inverter to supplement the pump power.

[0033] Threshold-triggered soft switching and power distribution are implemented based on the pressure window of the accumulator 711 and the DC bus voltage window.

[0034] When the DC bus is overvoltageed and the first DC-DC conversion module 725 has limited its power, the braking resistor module 727 is activated to protect the supercapacitor group 729.

[0035] Based on the above-mentioned method for recovering kinetic energy from the mold opening and closing system of a die-casting machine, the specific steps are as follows: Step S1: Divide the mold opening and closing cycle into working conditions based on the die-casting machine speed-time curve. For example... Figure 2As shown, the mold opening and closing cycle is divided into six working conditions: high-speed mold closing T1, low-speed mold closing T2, mold closing T3, low-speed mold opening T4, high-speed mold opening T5, and mold opening T6. Mold opening includes the high-speed to low-speed transition section T6-1 and the mold opening terminal deceleration section T6-2.

[0036] Step S2: Set the switching strategy according to the working condition classification.

[0037] Step S3: Based on the switching strategy and the collected operating data, switch between the peak hydraulic energy storage path 71 and the speed control electric side energy storage path 72 to realize energy recovery under different working conditions.

[0038] During the low-speed mold closing T2 and the high-speed to low-speed transition T6-1 stages, the return oil preferentially enters the accumulator 711 in the peak hydraulic energy storage passage 71 through the deceleration channel 73, forming a back pressure state; when the moving mold reaches the preset speed or displacement and requires precise deceleration control, the speed control electric side energy storage passage 72 is switched, and the energy is converted into electrical energy through the hydraulic motor / pump integrated machine 721 and stored in the supercapacitor group 729.

[0039] During the mold closing T3, low-speed mold opening T4, and the mold opening terminal deceleration section T6-2, the return oil passes through the deceleration channel 73 and preferentially enters the switching speed control electric side energy storage channel 72. Based on the electromagnetic torque closed-loop tracking deceleration or back pressure of the hydraulic motor / pump integrated machine 721, speed control and energy recovery of the moving mold speed curve are realized.

[0040] During the high-speed mold closing T1 and high-speed mold opening T5 stages, the accumulator 711 releases energy to achieve peak performance and establishes a high-speed operating state. When the pressure of the accumulator 711 drops to the lower limit, it switches to the speed control electric side energy storage path 72 and drives the hydraulic motor / pump integrated machine 721 to replenish energy through the supercapacitor group 729.

[0041] Threshold soft switching and power distribution are implemented based on the pressure window of the energy storage device 711 and the DC bus voltage window; when the bus voltage exceeds the first threshold, the power is limited first, and if it still exceeds the threshold, the braking resistor module 727 is activated to absorb the excess energy.

[0042] Before shutdown or maintenance, the first control valve 712 and the second control valve 722 enter a safe operating condition, and the temperature of the supercapacitor bank 729 is within the set temperature range. The residual energy of the accumulator 711 is converted by the hydraulic motor / pump integrated machine 721 and stored in the supercapacitor bank 729. The high-voltage contactor 726 is disconnected to de-energize the DC bus. When the temperature of the supercapacitor bank 729 is not within the set temperature range, the energy is released by the brake resistor module 727.

[0043] The specific process is as follows: High-speed mold closing T1 stage: Valve positions: First reversing valve in left position, second reversing valve 4 in left position; third reversing valve 741 in right position, cartridge valve 742 open; first control valve 712 first in left position then in right position, accumulator 711 releases energy, second control valve 722 first in right position then in left position, electric side backup.

[0044] Process: The accumulator 711 releases energy first to rapidly increase the flow rate. When the energy storage approaches its lower limit, the first control valve 712 closes, and the second control valve 722 opens. The shared supercapacitor drives the M / G pump to continue supplying flow, maintaining high speed. The specific oil circuit is as follows: Figure 3 As shown.

[0045] Low-speed mold closing T2 stage (energy recovery): Valve positions: First directional valve 3 left position, second directional valve 4 neutral position; third directional valve 741 left position (cartridge valve 742 closed); first control valve 712 left position (open), second control valve 722 right position (closed). During low-speed mold closing, the first directional valve 3 is in the left position, the second directional valve 4 is in the neutral position, the differential connection of the mold opening / closing hydraulic cylinder 1 is released, the third directional valve 741 is in the left position, and the cartridge valve 742 is closed. The first control valve 712 is in the left position (open), and the second control valve 722 is in the right position (closed). The return oil from the rod chamber 12 enters the accumulator 711 through the first control valve 712, converting the kinetic energy of the moving mold into the potential energy in the accumulator 711, causing the speed of the moving mold to decrease rapidly. When an unexpected cause causes overpressure in the accumulator 711, the safety valve 714 can be opened to release the excess pressure. The oil circuit is as follows: Figure 4 As shown, this stage is the energy recovery process.

[0046] Process: The return oil from the rod chamber 12 enters the accumulator 711 through the first control valve 712, converting kinetic energy into potential energy, and the cylinder speed decreases rapidly. When approaching the upper limit of energy storage, the first control valve 712 closes, the second control valve 722 opens, and the excess kinetic energy is transferred to the supercapacitor system. If an unexpected cause leads to overpressure in the accumulator 711, the safety valve 714 can be opened to release the excess pressure.

[0047] Mold closing T3 stage: Valve positions: First directional valve 3 left position, second directional valve 4 neutral position; third directional valve 741 left position (cartridge valve 742 closed); first control valve 712 right position (closed), second control valve 722 left position (open).

[0048] Process: The return oil from the rod chamber 12 drives the integrated hydraulic motor / pump 721 (motor mode), converting the kinetic energy of the mold-opening and closing hydraulic cylinder 1 into electrical energy. This electrical energy is then converted into electrical energy via a bidirectional three-phase active rectifier module 723, a filter 724, and a first DC-DC converter module 725. The converted electrical energy is then passed through a high-voltage contactor 726 and finally stored in the supercapacitor bank 729. The output of the filter 724 is monitored. When the output of the filter 724 is DC 680-760V, it directly connects to the high-voltage contactor 726 to output electrical energy to the shared supercapacitor bank 729. If the output of the filter 724 does not meet the requirements, the first DC-DC converter module 725 converts the electrical energy into electrical energy within the set range before outputting it to the shared supercapacitor bank 729. During this process, the supercapacitor management module 7291 monitors the status of the shared supercapacitor bank 729. When there is excessive energy recovery or the temperature of the supercapacitor bank 729 is too high, the braking resistor module 727 is activated. By configuring the electromagnetic torque, the speed of the mold opening / closing hydraulic cylinder 1 can be precisely controlled until it stops at the end position, completing the mold closing process, as follows: Figure 5 As shown.

[0049] Low-speed mold opening, T4 stage: Valve positions: First directional valve 3 right position, second directional valve 4 neutral position; third directional valve 741 left position (cartridge valve 742 closed); first control valve 712 right position (closed), second control valve 722 left position (open).

[0050] Process: High-pressure oil flows into the rod chamber 12, pushing the piston rod forward. The back pressure in the rodless chamber 11 is precisely controlled by the integrated hydraulic motor / pump 721, achieving smooth vacuum breaking of the mold and effective detection of the separation state of the moving and fixed molds. At the same time, the return oil energy is recovered to the supercapacitor group 729, as follows: Figure 6 As shown.

[0051] High-speed mold opening T5 stage: Valve positions: First directional valve 3 is in the right position; second directional valve 4 is in the right position; third directional valve 741 is in the right position (cartridge valve 742 is open); first control valve 712 is in the left position first and then the right position (open → closed); second control valve 722 is in the right position first and then the left position (closed → open).

[0052] Process: First, the accumulator 711 directly releases potential energy to provide peak flow, rapidly increasing the operating speed of the mold opening and closing hydraulic cylinder 1. When the pressure of the accumulator 711 approaches the lower limit, the first control valve 712 closes and the second control valve 722 opens. The supercapacitor drives the hydraulic motor / pump integrated machine 721 to provide additional hydraulic flow to the hydraulic system, maintaining the mold opening and closing hydraulic cylinder 1 in a high-speed mold opening state, as follows: Figure 7 As shown.

[0053] Mold opening stage T6: Valve positions: First directional valve 3 is in the right position; second directional valve 4 is in the neutral position; third directional valve 741 is in the left position; first control valve 712 is in the left position first and then in the right position (open → closed); second control valve 722 is in the right position first and then in the left position (closed → open).

[0054] Process: The hydraulic oil in the rodless chamber 11 is first absorbed by the accumulator 711, rapidly reducing the speed of the mold opening and closing hydraulic cylinder 1. When the preset speed or position is reached, the accumulator 711 circuit closes, the supercapacitor circuit opens, and the oil is regenerated and recovered to the supercapacitor group 729 via the hydraulic motor / pump integrated machine 721. Flexible deceleration and positioning stop of the mold opening and closing hydraulic cylinder 1 are achieved through an electromagnetic torque closed loop. Figure 8 As shown.

[0055] Energy transfer before shutdown or maintenance: Valve Position: To reduce downtime risks and the impact of static leakage from accumulator 711, the first control valve 712 and the second control valve 722 can be simultaneously placed in the left position (open). At the same time, the motor and hydraulic pump in the main oil circuit are shut down. The residual pressure of accumulator 711 drives the integrated hydraulic motor / pump 721, converting the potential energy of accumulator 711 into electrical energy and storing it in the supercapacitor bank 729. This facilitates cross-equipment sharing and subsequent reuse, as follows: Figure 9 As shown.

[0056] This embodiment implements the above scheme for a die-casting machine with a clamping force of 800T. The parameters of the die-casting machine are as follows: Cylinder diameter: 280mm; Rod diameter: 196mm; Rodless chamber cross-sectional area 11 0.061575 ; Cross-sectional area of ​​the rod cavity 12 0.031327 The working cycle of the die-casting machine is 40 seconds.

[0057] Speed ​​requirement: Altitude range: Mid-range deceleration: ; Approximate calculation using a uniformly decelerated process: ; Terminal deceleration: ; Approximate calculation using a uniformly decelerated process: .

[0058] Pressure requirements: mold closing end ; mold opening end ; Mid-section unification ; The conversion efficiencies of each part are as follows: Accumulator 711 (hydraulic airbag): Filling efficiency: Energy release efficiency: ; Electrical side (battery / supercapacitor and M / G): Input efficiency: Output efficiency: ; The calculation results are as follows: The operation of the mold opening and closing hydraulic cylinder 1 is divided into six stages. Since there is no energy recovery during the high-speed mold opening and high-speed mold closing stages, only the remaining four stages need to be considered. The energy recovery for these four stages is as follows: Buffer section at the end of mold opening: ; Mold closing end buffer section: ; Mold opening section: ; Mold closing section: ; The total energy is as follows: ; The energy storage device 711 and the electrical side are allocated in a ratio of 7:3. ; ; ; ; 68.15KJ is distributed as injection power to both sections in the high-speed section, directly offsetting the power supply of the main pump.

[0059] The energy recovery rate and utilization rate are as follows: Total energy recovery rate (stored in accumulator 711 and capacitor): ; Overall energy recovery efficiency (releasable energy): .

[0060] Baseline main pump rated power before optimization: ; Using the technical solution of this embodiment, the rated power of the main pump can be [missing information]. The 28.2% decrease in power consumption, along with the downgrading and cost reduction of motors, frequency converters, and power distribution capacitors, has a positive impact on system startup impact and grid power demand. Simultaneously, the reduction in main pump power will further reduce power losses during equipment overflow.

[0061] In this embodiment, the oil volume is 200L. Based on ρ≈0.9kg / L→mass≈180kg, cp is the specific heat of the oil, which is taken as cp≈1.9kJ / (kg·K), and the cycle N=1.5 times / min (cycle 40s).

[0062] Baseline oil-side heat per minute: ; ; After adopting the technical solution of this embodiment, the oil-side heat per minute is as follows: ; ; The temperature rise difference is approximately 0.339 K / min, and the temperature rise difference over 60 minutes is approximately 20.34 K. The technical solution of this embodiment can significantly reduce the burden on the cooling system.

[0063] Oil-side heating Reduce to (89.2% decrease relative to the baseline). Cooling load decreased by 1.93kW, oil temperature became more stable, and leakage and wear decreased.

[0064] High-speed opening / closing mold subsystem saves energy: Under a 40-second work cycle: During the mold opening and closing process, it directly saves 15.95% of electricity. With the addition of energy recovery, the decrease in hydraulic oil temperature leads to a decrease in the power consumption of the cooling system (fan / water pump), and the system's energy saving rate will be further improved.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A die casting machine mold opening and closing kinetic energy recovery system comprising a mold opening and closing hydraulic cylinder, a main oil pump, a first directional control valve, and a second directional control valve, the mold opening and closing hydraulic cylinder having a rodless chamber and a rod chamber, the first directional control valve being provided on a first passage between the main oil pump and the rodless chamber, the second directional control valve being provided on a second passage between the first directional control valve and the rod chamber, characterized in that: The mixed energy recovery unit comprises a peak-holding hydraulic energy storage passage and a speed control electric side energy storage passage, a connection point of the peak-holding hydraulic energy storage passage and the speed control electric side energy storage passage is connected with the deceleration passage, and the first reversing valve and the second reversing valve are arranged on the deceleration passage; the connection point of the peak-holding hydraulic energy storage passage and the speed control electric side energy storage passage is connected with one end of the acceleration passage, the other end of the acceleration passage is connected on the first passage between the first reversing valve and the main oil pump, and the acceleration passage is provided with the third reversing valve in parallel, for controlling the opening and closing of the cartridge valve on the acceleration passage; The control unit is used for collecting operation data of the opening and closing mold hydraulic cylinder and the mixed energy recovery unit, and switching the peak-holding hydraulic energy storage passage and the speed control electric side energy storage passage according to the operation data.

2. The die casting machine mold opening and closing kinetic energy recovery system in accordance with claim 1, characterized by: At least one accumulator and a first control valve are arranged on the peak-holding hydraulic energy storage passage, the first control valve is used for controlling the oil return direct charging and energy release of the accumulator, a safety passage is connected between the accumulator and the first control valve on the peak-holding hydraulic energy storage passage, and a safety valve is arranged at the tail end of the safety passage, for limiting the maximum pressure of the accumulator.

3. The die casting machine mold opening and closing kinetic energy recovery system in accordance with claim 2, characterized by: A hydraulic motor / pump integrated machine and a second control valve are arranged on the speed control electric side energy storage passage, the hydraulic motor / pump integrated machine is connected with a bidirectional three-phase active rectification module, the bidirectional three-phase active rectification module is connected with a filter, the filter is connected with a first DC-DC conversion module, the first DC-DC conversion module and the filter are connected with a high-voltage contactor, the high-voltage contactor is connected with a super capacitor group and is provided with a brake resistance module, and the super capacitor group is connected with the bidirectional three-phase active rectification module through a second DC-DC conversion module.

4. The die casting machine mold opening and closing kinetic energy recovery system in accordance with claim 3, characterized by: The super capacitor group is provided with a super capacitor management module, the super capacitor management module is used for voltage equalization, temperature monitoring and health state monitoring and evaluation of the super capacitor group, the super capacitor group is connected with a direct current bus, and the direct current bus is connected with an energy interface of an energy consumption device to realize energy sharing.

5. The die casting machine mold opening and closing kinetic energy recovery system in accordance with claim 3, characterized by: The deceleration passage and the acceleration passage are each provided with a check valve or a shuttle valve for preventing mutual backflow of electro-hydraulic passages.

6. The die casting machine mold opening and closing kinetic energy recovery system in accordance with claim 3, characterized by: The first passage, the deceleration passage and the acceleration passage are each connected with an overflow valve.

7. The die casting machine mold opening and closing kinetic energy recovery system in accordance with claim 3, characterized by: The control unit is used for collecting operation data of the opening and closing mold hydraulic cylinder and the mixed energy recovery unit, and switching the peak-holding hydraulic energy storage passage and the speed control electric side energy storage passage according to the operation data. The pressure acquisition module is used for collecting accumulator pressure. The electric parameter acquisition module is used for collecting voltage of the direct current bus. The opening and closing mold parameter acquisition module is used for collecting displacement and speed of the opening and closing mold The temperature acquisition module is used for collecting oil temperature and environmental temperature, for temperature compensation of subsequent accumulator pressure values. In the energy recovery stage, the peak-holding hydraulic energy storage passage is preferentially opened, so that the oil return is directly charged to the accumulator; when the movable mold reaches a preset displacement or speed, and the precision deceleration control needs to be set, the speed control electric side energy storage passage is switched on, so that the oil return drives the hydraulic motor / pump integrated machine, and the converted electric energy is stored in the super capacitor group. The first control valve is preferentially opened in the energy release stage to make the accumulator release energy to the mold opening and closing hydraulic cylinder to provide peak flow; when the accumulator pressure drops to a lower threshold, the speed control electric side energy storage passage drives the hydraulic motor / pump integrated machine as a pump to supplement power; According to the accumulator pressure window and the DC bus voltage window, threshold triggered soft switching and power distribution are implemented; When the DC bus is overvoltage and the first DC-DC conversion module has limited power, the brake resistance module is put into operation to protect the super capacitor group.

8. The recovery method of the die casting machine mold opening and closing kinetic energy recovery system according to claim 7, characterized in that, The specific steps are as follows: Step S1: According to the die casting machine speed-time curve, the mold opening and closing cycle is divided into working conditions; Step S2: According to the working condition division, the switching strategy is set; Step S3: According to the switching strategy and the collected operation data, the peak-holding hydraulic energy storage passage and the speed control electric side energy storage passage are switched to realize energy recovery in different working conditions.

9. The recovery method of a die casting machine opening and closing mold kinetic energy recovery system according to claim 8, characterized in that: The mold opening and closing cycle is divided into six working conditions, which are high-speed die closing T1, low-speed die closing T2, die closing T3, low-speed mold opening T4, high-speed mold opening T5 and mold opening T6. Mold opening includes high-speed to low-speed transition section T6-1 and mold opening terminal deceleration section T6-2.

10. The method of claim 9, wherein: In the low-speed die closing T2 and high-speed to low-speed transition section T6-1 stage, the oil return preferentially enters the accumulator in the peak-holding hydraulic energy storage passage through the deceleration channel to form a back pressure state; when the moving die reaches the preset speed or displacement and needs to set the precision deceleration control, the speed control electric side energy storage passage is switched, and the energy is converted into electrical energy by the hydraulic motor / pump integrated machine and stored in the super capacitor group; In the die closing T3, low-speed mold opening T4 and mold opening terminal deceleration section T6-2 stage, the oil return preferentially enters the switched speed control electric side energy storage passage through the deceleration channel, and the electromagnetic torque of the hydraulic motor / pump integrated machine is closed loop tracked according to the deceleration or back pressure to realize the speed control and energy recovery of the moving die speed curve; In the high-speed die closing T1 and high-speed mold opening T5 stage, the accumulator releases energy to hold the peak, and establishes a high-speed running state; when the accumulator pressure drops to the lower limit, the speed control electric side energy storage passage is switched, and the hydraulic motor / pump integrated machine is driven by the super capacitor group to supplement energy; Threshold soft switching and power distribution are implemented based on the accumulator pressure window and the DC bus voltage window; when the bus voltage exceeds the first threshold, the power is limited, and when it still exceeds the threshold, the brake resistance module is put into operation to absorb excess energy; Before shutdown or maintenance, the first control valve and the second control valve enter the safe working condition, and the temperature of the super capacitor group is within the set temperature range, so that the residual energy of the accumulator is converted by the hydraulic motor / pump integrated machine and stored in the super capacitor group, and the high-voltage contactor is disconnected to make the DC bus power off; when the temperature of the super capacitor group is not within the set temperature range, the brake resistance module is used for energy release.

Images