A near-liquidus extrusion casting forming apparatus

Abstract

The application discloses a near-liquid line extrusion casting forming equipment, which comprises a support, a mold closing mechanism, a driving mechanism and a screw feeding mechanism arranged on the support, wherein the screw feeding mechanism is provided with a driving cylinder on the side away from the connection with the mold closing mechanism, and the driving cylinder is provided with an adjusting mechanism capable of controlling the gas flow and the gas pressure; the adjusting mechanism increases the gas flow to realize high-speed pre-feeding of the feeding screw rod to inject the melt into the mold closing mechanism in the injection stage when the melt does not fill the mold closing mechanism, or reduces the gas flow and increases the gas pressure to realize slight pre-feeding of the feeding screw rod to compensate the melt shrinkage by pressure in the pressure maintaining stage when the melt fills the mold closing mechanism; the adjusting mechanism is controlled by a control system, and the control system is used to automatically switch the working state of the adjusting mechanism in the injection stage or the pressure maintaining stage. The application has the beneficial effects of realizing high-quality, high-efficiency and high-stability production of the near-liquid line extrusion casting.

Description

Technical Field

[0001] This invention relates to the field of casting equipment technology, and in particular to a near-liquidline extrusion casting equipment. Background Technology

[0002] Near-liquidline extrusion casting is an advanced special forming process. It involves holding the molten metal near its liquidus temperature, then filling the mold at high pressure and speed while maintaining continuous pressure to compensate for shrinkage, ultimately obtaining a dense casting with excellent mechanical properties. This process is particularly suitable for the precision forming of light alloys such as aluminum and magnesium alloys, effectively reducing defects such as porosity and shrinkage, and improving the strength and fatigue resistance of the parts.

[0003] Currently, near-liquidline extrusion casting equipment typically consists of a mold clamping mechanism, an injection mechanism, a hydraulic or pneumatic drive system, and a control system. During the process, the injection stage requires the melt to fill the mold cavity at a high velocity to prevent premature solidification, which could lead to incomplete filling or cold shuts. In the holding pressure stage after filling, higher pressure is needed to push the melt for micro-feeding, compensating for solidification shrinkage and improving the density of the casting. However, existing equipment still faces several technical bottlenecks in switching and controlling between "high-speed injection" and "high-pressure, low-speed holding": Stage switching relies on a single signal and has a delayed response: Most systems rely solely on position sensors or time control for stage switching, which cannot detect the actual filling status of the cavity in real time, easily causing the switching to be too early or too late, affecting the quality of the casting.

[0004] Injection and holding pressure power coupling, insufficient control precision: Traditional hydraulic or pneumatic systems often share the same power source and achieve parameter conversion at different stages through valve adjustment. However, there is a contradiction between the high flow rate requirement in the injection stage and the high pressure stability requirement in the holding pressure stage, which is difficult to balance and can easily lead to pressure fluctuations and discontinuous compensation.

[0005] Low energy utilization efficiency and poor system stability: High-pressure fluid is often continuously introduced during the pressure holding stage, which not only consumes a lot of energy, but also makes it easy for the pressure holding stability to be affected by the pressure pulsation of the pump source or gas source, which is not conducive to long-term, high-precision pressure maintenance.

[0006] The coordination between mechanical and control systems is weak: existing equipment mostly uses a combination of distributed control solenoid valves and sensors. The action connection of each actuator depends on the program delay. It lacks real-time closed-loop feedback and rapid mechanism linkage based on the actual forming state of the melt, making it difficult to achieve millisecond-level precise switching and smooth pressure transition. Summary of the Invention

[0007] The present invention aims to overcome the shortcomings of the prior art by providing a near-liquidline extrusion casting molding apparatus to solve the above problems.

[0008] The technical solution adopted by this invention to solve its technical problem is as follows: This near-liquidline extrusion casting molding equipment includes a support frame, on which a mold closing mechanism is provided. A drive mechanism connected to the mold closing mechanism is provided on one side of the mold closing mechanism to drive the mold closing mechanism to open or close the mold, and a screw feeding mechanism connected to the mold closing mechanism is provided on the other side. A drive cylinder is provided on the side of the screw feeding mechanism away from its connection with the mold closing mechanism. The drive cylinder is provided with an adjustment mechanism that can control the gas flow rate and gas pressure. When the melt has not filled the mold closing mechanism during the injection stage, the adjustment mechanism increases the gas flow rate to enable the feeding screw to advance at high speed and inject the melt into the mold closing mechanism. Or, when the melt has filled the mold closing mechanism during the holding pressure stage, the adjustment mechanism decreases the gas flow rate and increases the gas pressure to enable the feeding screw to move forward slightly to compensate for the shrinkage of the melt. The adjustment mechanism is controlled by a control system, which is used to automatically switch the working state of the adjustment mechanism during the injection stage or the holding pressure stage.

[0009] Further improvements include an adjustment section and a distribution section. The adjustment section has two air passages, which do not flow simultaneously. One air passage flows during the injection stage when the melt has not filled the mold closing mechanism, and the other air passage flows during the pressure holding stage when the melt has filled the mold closing mechanism. The distribution section delivers the gas supplied by the gas generating equipment into the adjustment section and can match the selective airflow of the adjustment section, or prevent gas from entering when the gas volume is sufficient to drive the cylinder.

[0010] Further improvements include an adjustment unit housing, and within the housing, a first air inlet channel, a first air chamber, a first air outlet channel, a second air inlet channel, a second air outlet channel, a second air chamber, and an air outlet channel. The first air inlet channel, first air chamber, first air outlet channel, second air chamber, and air outlet channel constitute an injection air outlet path, while the second air inlet channel, second air outlet channel, second air chamber, and air outlet channel constitute a pressure-holding air outlet path. The first air inlet channel is equipped with a spring-loaded member that applies force to the first air chamber. The first plug is used to block the inlet of the second air inlet channel. The second plug is installed in the second air inlet channel and is used to block the inlet of the second air outlet channel by applying force through an elastic component. When the second plug releases the blockage of the inlet of the second air outlet channel, it also blocks the first air outlet channel at the same time. After the blockage, the amount of gas entering the second air chamber through the second air outlet channel and entering the first air outlet channel is reduced. The first air outlet channel is equipped with a speed regulating component near the inlet to increase the gas flow rate and velocity. The second air chamber is equipped with a pressure regulating component to increase the gas pressure.

[0011] Further improvements include a second air chamber comprising a drive section and a pressurization section. The drive section is used to house the pressure regulating components. Part of the space in the pressurization section is used to receive the gas delivered by the first air passage during the injection stage and to receive the gas delivered by the second air passage during the pressure holding stage. The remaining space is used as the activity space for part of the pressure regulating components.

[0012] Further improvements include a speed regulating component comprising a turbine blade and a guide plate. The first air passage has an L-shaped configuration, with a turbine blade positioned near its vertical section in its transverse section. The guide plate is located on the side of the turbine blade away from the outlet of the first air passage and is inclined, so that the gas contacts the turbine blade from a position slightly to the left of the turbine blade via the guide plate.

[0013] Further improvements include a pressure regulating component comprising a moving rod and a drive wheel for driving the moving rod to move. The moving rod moves simultaneously within a driving section and a pressurizing section, and has a semi-circular protrusion at one end near the drive wheel. The drive wheel's profile includes at least four working surfaces, namely a first working surface, a second working surface, a third working surface, and a fourth working surface. When the drive wheel rotates uniformly around its central axis, it can sequentially drive the moving rod to produce four different propulsion strokes. The lengths of the four propulsion strokes increase arithmetically. Adjacent drive wheel working surfaces are connected by a smooth transition surface. The smooth transition surface contacts the moving rod when adjacent cam working surfaces transition from one to the other, keeping the propulsion stroke constant.

[0014] Further improvements were made, ensuring that the central angles of the four working surfaces around the central axis are all equal, and that the contour line of the smooth transition surface is tangent to the working surfaces of the two adjacent cams.

[0015] Further improvements include a branch section comprising a branch section housing and a branch switching block rotatably disposed within the branch section housing. The branch section housing is hollow inside, and its outer circumference is provided with one air inlet and two air outlets communicating with the hollow portion. The air inlet is used to connect to the gas generating equipment pipe, and the center lines of the two air outlets are arranged at a 90° angle. One air outlet is connected to a pipe connector located at the air inlet of the first air inlet channel, and the other air outlet is connected to a pipe connector located at the air inlet of the second air inlet channel. Branch switching... During the injection stage, the block blocks the outlet end connected to the pressure-holding air supply pipe but not the outlet end connected to the injection air supply pipe. Conversely, during the pressure-holding stage, the block blocks the outlet end connected to the injection air supply pipe but not the outlet end connected to the pressure-holding air supply pipe. When the gas volume is sufficient to drive the drive cylinder, the branch switching block simultaneously blocks both outlet ends to stop the air intake. Then, the pressure is increased by the pressure regulating movement of the pressure regulating component to slowly advance the piston rod of the drive cylinder.

[0016] Further improvements include the addition of a third, fourth, and fifth plug on the outer periphery of the branch switching block. The centerlines of the third and fourth plugs are arranged at a 115° angle, while the centerlines of the fourth and fifth plugs are arranged at a 38° angle. This arrangement ensures that during the injection phase, the fourth plug seals the corresponding air outlet, while the third and fifth plugs do not. During the pressure holding phase, the third plug seals the corresponding air outlet, while the fourth and fifth plugs do not. When the gas volume is sufficient to move the drive cylinder, both the third and fifth plugs seal the corresponding air outlet. Each of the third, fourth, and fifth plugs is fitted with a sealing rubber head. The length of the sealing rubber head of the third plug is greater than that of the sealing rubber heads of the fourth and fifth plugs, while the lengths of the sealing rubber heads of the fourth and fifth plugs are equal.

[0017] Further improvements were made to the control system, which includes a human-machine interaction module, a logic control module, a regulation module, and a signal acquisition module. The human-machine interaction module is electrically connected to the logic control module, the logic control module is electrically connected to the regulation module and the signal acquisition module, the regulation module is electrically connected to the adjustment mechanism, and the signal acquisition module is electrically connected to the cavity pressure sensor installed in the mold closing mechanism and / or the position sensor connected to the drive cylinder. The human-machine interface module is used to set process parameters and display equipment status. Its setting parameters include the switching pressure threshold between the injection stage and the holding stage, the holding pressure setting value, and the holding time. The signal acquisition module is used to acquire the cavity pressure signal fed back by the cavity pressure sensor and / or the screw displacement signal fed back by the position sensor in real time, and transmit the signal to the logic control module. The logic control module includes a stage judgment unit and an instruction generation unit. The stage judgment unit is used to continuously compare the real-time data fed back by the signal acquisition module with the preset switching threshold. When the real-time cavity pressure reaches the switching pressure threshold or the real-time feed screw displacement reaches the preset position, it is determined that the melt is full and a switching signal from the injection stage to the holding pressure stage is generated. The instruction generation unit is used to generate corresponding control instruction combinations according to the current stage status: In the injection stage, the control branch is converted to the state of supplying gas to the injection gas path. After the injection is completed and the switching signal is received, the control branch is immediately converted to the state of switching to supplying gas to the holding pressure gas path and shutting off the supply of gas to the injection gas path. After the gas supply in this stage is completed and the switching signal is received, the control branch is converted to the state of simultaneously stopping the gas intake of the two gas paths and controlling the pressure regulating component to start increasing the output gas pressure. The control module directly receives and executes the control commands issued by the logic control module. It includes a first drive unit and a second drive unit. The first drive unit is electrically connected to the branch section and is used to control the selective conduction of one of the two air passages in the branch section or the non-conduction of both air passages. The second drive unit is electrically connected to the pressure regulating component and is used to control the gas pressure output to the drive cylinder.

[0018] The beneficial effects of this invention are: 1. This invention achieves decoupled control of gas flow and pressure by physically isolating the gas flow path for injection and the gas flow path for pressure holding, and by equipping them with dedicated speed regulating and pressure regulating components. During the injection stage, a large flow rate and high velocity gas drive can be obtained to ensure rapid filling. During the pressure holding stage, a high pressure, low flow rate and extremely stable gas supply can be obtained to ensure precise and continuous micro-compensation. The power of the two stages does not interfere with each other, which fundamentally guarantees the optimization and stability of their respective process parameters. 2. During the pressure holding stage, the control system can instruct the branch section to switch to the "stop air intake" state, actively cutting off the main air source supply, so that the drive cylinder and related pipelines form a closed high-pressure gas-capacity system. The subsequent pressure maintenance and fine adjustment are completely completed by the pressure regulating component in the closed system through precise mechanical compensation. This not only greatly reduces the energy consumption caused by the continuous introduction of high-pressure fluid, but also completely isolates the interference of remote air source pressure pulsation, making the pressure holding pressure extremely stable. This is conducive to long-term, high-precision pressure maintenance, thereby obtaining castings with denser structure and better performance. 3. The present invention can sense the melt filling status (pressure or position) in real time through the control system, and automatically and accurately trigger the switching from the high-speed injection stage to the high-pressure holding stage within milliseconds. This overcomes the defects of traditional equipment that rely on a single signal, resulting in switching too early or too late. It effectively avoids quality problems such as insufficient filling, cold shut or pressure shock, and significantly improves the consistency and reliability of casting. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the structure of the drive cylinder and adjustment mechanism of the present invention; Figure 3 This is a schematic diagram of the structure of the adjustment part of the present invention; Figure 4 This is a schematic diagram of the branch section of the present invention, used to illustrate the state during the injection stage; Figure 5 This is a schematic diagram of the branch section of the present invention, used to illustrate the state during the pressure holding stage; Figure 6 This is a schematic diagram of the branch section of the present invention, used to illustrate the state of preventing gas from entering during the pressure holding stage; Figure 7 This is a schematic diagram of the control system of the present invention. Detailed Implementation

[0020] The present invention will be further described below with reference to the accompanying drawings: Referring to the attached diagram: This near-liquidline extrusion casting molding equipment mainly includes a support frame 1, a mold closing mechanism 2, a drive mechanism 3, a screw feeding mechanism 4, a drive cylinder 5, an adjustment mechanism 6, and a control system 9. The support frame 1 serves as the basic support frame for the entire equipment. The mold closing mechanism 2 is installed on the support frame 1. The mold closing mechanism 2 includes a fixed mold and a moving mold, and has a forming cavity for forming the casting. The drive mechanism 3 is installed on one side of the mold closing mechanism 2. The drive mechanism 3 is connected to the moving mold part of the mold closing mechanism 2 and is used to drive the moving mold to move, thereby realizing the mold opening and closing actions of the mold closing mechanism. The drive mechanism 3 consists of a servo motor, a slide rail slider structure, and a pulley.

[0021] On the other side of the mold clamping mechanism 2, a spiral feeding mechanism 4 is provided. The spiral feeding mechanism 4 typically includes a barrel and a feeding screw installed therein. A fixing plate is welded to the end of the barrel away from the mold clamping mechanism 2. The fixing plate is fixed to the bracket 1 by bolts. The other end of the barrel is a discharge port (inserted into the mold gate) connected to the mold gate of the mold clamping mechanism 2, thus achieving the fixed setting of the barrel. The movement of the feeding screw installed in the barrel can be either rotation or movement. When rotating, it can transport and accumulate the near-liquid phase semi-solid melt from the melting and holding furnace into the storage chamber at the front end of the barrel. Movement is achieved by a drive cylinder 5 connected to the rear end of the feeding screw. The drive cylinder 5 is used to push the feeding screw to move forward or backward along its axis, thereby injecting the melt in the storage chamber into the cavity of the mold clamping mechanism 2.

[0022] The drive cylinder 5 is also equipped with an adjustment mechanism 6, which is controlled by the control system 9. Under the control of the control system 9, the adjustment mechanism 6 can independently and precisely adjust and control the flow rate and pressure of the working gas supplied to the drive cylinder 5. This can meet the process of "high-speed injection filling followed by high-pressure low-speed shrinkage compensation" of near-liquidity line extrusion casting equipment. High-speed injection ensures complete filling of complex thin-walled cavities and reduces defects such as cold shuts and incomplete filling. High-pressure low-speed holding achieves effective pressure compensation for the solidification process, which greatly reduces shrinkage cavities and porosity inside the casting and improves the density and mechanical properties of the casting. At the same time, precise stage control helps to shorten the entire molding cycle and improve production efficiency.

[0023] The regulating mechanism 6 mainly includes two core functional parts: the regulating section 61 and the branch section 62. The regulating unit 61 is the core actuator for achieving differentiated control of pneumatic parameters during the injection and holding pressure stages. Its internal structure has two air passages that are not opened simultaneously. This design aims to achieve completely different dynamic characteristics for the two process stages. One air passage is dedicated to the injection stage. This passage is designed as a low-resistance, large-diameter, high-speed channel. When this passage is open, it allows the working gas to pass through at a very high flow rate, thereby driving the cylinder piston and the feeding screw to achieve the required high-speed forward motion and ensure rapid filling of the melt. The other air passage is dedicated to the holding pressure stage. When this passage is open, the gas pressure entering the drive cylinder 5 can be precisely increased and stabilized at a preset high-pressure value (e.g., much higher than the system's main air source pressure), while the allowed flow rate is limited to a very low level. This provides a precise air source for achieving "high-pressure, micro-volume, and stable" forward movement of the feeding screw. The branch section 62 is used as an intelligent gas distribution component and is located between the gas generating equipment (such as an air compressor and a gas storage tank) and the regulating section 61. It is mainly used for gas delivery and path matching. The branch section 62 guides the gas delivered from the gas generating equipment to the gas path that needs to be opened in the regulating section 61 according to the instructions of the control system 9. It ensures that the gas can be accurately delivered to the correct path and stops supplying gas to both gas paths when the gas quantity is sufficient to drive the drive cylinder to move. This setup not only precisely achieves differentiated control of injection and holding pressure, but also brings significant benefits such as faster switching, more precise control, and better energy efficiency through physically isolated gas path design and intelligent gas supply management, fundamentally optimizing the dynamic process of near-liquidline extrusion casting.

[0024] The regulating unit 61 includes a regulating unit housing 611, inside which two independent and functionally defined gas passages are formed. One gas passage is for injection (corresponding to the injection stage), and this gas passage is composed of the following parts connected in sequence: First air intake channel 612: used to connect to branch section 62, is the gas inlet during the injection stage. It is equipped with a first plug 6121 inside. The plug is normally closed under the pre-tightening force of a light spring (elastic component), blocking the inlet to the first air chamber 613. First air chamber 613: An air storage chamber with a certain volume; First air passage 614: a key passage connecting the first air chamber 613 with the subsequent chambers, with a speed regulating component 7 installed near the inlet; Second air chamber 617: A common chamber with integrated pressure regulation function; Exhaust passage 618: The passage that ultimately directs the gas to drive cylinder 5.

[0025] The other gas path is the pressure-holding gas path (corresponding to the pressure-holding stage), which is composed of the following parts connected in sequence: The second air intake passage 615 is connected to the branch section 62 and is the gas inlet during the pressure holding stage. It is equipped with a second plug 6151, which is normally closed under the action of a light spring, blocking the inlet of the second air outlet passage 616. Second air passage 616: connected to second air inlet passage 615 and directly leads to second air chamber 617; Second air chamber 617: Same as above, is a common chamber; Air vent 618: Same as above.

[0026] The first plug 6121 and the second plug 6151 are designed with a specific shape (e.g., the sealing part is conical). When the pressure-holding control air pressure from the branch section 62 acts on its end face, overcoming the spring force and moving it in the opening direction, the second plug 6151 performs two actions: one is to open the pressure-holding air passage, releasing the blockage on the inlet of the second air passage 616 as it leaves the inlet; and the other is that, simultaneously, a specific part of its part (the rod-shaped component facing away from the conical part) will... Insert and seal a certain position in the first air passage 614 (the position is near the outlet of the first air passage 614). This mechanical linkage design ensures the absoluteness and instantaneity of the switch from "injection" to "pressure holding". Once the pressure holding stage is entered, not only is the pressure holding air passage opened, but the amount of gas entering the first air passage 614 through the second air passage 616 into the second air chamber 617 is also physically reduced, realizing the "hard isolation" of the two air passages. This is the fundamental way to ensure the stability of the pressure holding pressure. The speed regulating component 7 is located near the inlet of the first air passage 614, which enables the injection stage to obtain a higher gas flow rate and flow rate than ordinary straight-through pipes, thereby more efficiently converting gas pressure energy into the kinetic energy of the piston rod driving the cylinder and achieving a faster injection speed. The pressure regulating component 8 is located in the second air chamber 617. Its core function is to regulate and stabilize the pressure of the gas entering from the second air passage 616, ensuring that the gas pressure output to the outlet passage 618 is accurate and constant at the preset high pressure value. It eliminates the direct impact of slight fluctuations in the gas supply pressure of the branch section 62 or changes in gas flow on the pressure holding pressure, and provides an extremely stable high pressure source for the drive cylinder 5. It is the key to achieving stable and accurate "micro-advance" compensation action.

[0027] The second gas chamber 617 is not a simple straight pipe, but is precisely divided into three sections that are closely connected in space and function: the drive section 6171 and the pressurization section 6172. This "two-section" structural design is the key to achieving precise pressure management and efficient energy transfer. The drive section 6171 is the starting part of the second gas chamber 617, and its core function is to install the pressure regulating component 8. The pressurization section 6172 is a multifunctional chamber. The main part of the space is used for gas reception and containment, and it is also used to contain part of the pressure regulating component 8, providing a precise installation reference and guide for the pressure regulating component 8. Moreover, the part that receives gas is located upstream of the pressure regulating component 8, ensuring that the gas pressure from the second gas outlet channel 616 (pressure holding stage) can be treated once before entering the gas outlet channel 618, laying a solid foundation for the stability of the amplified output pressure.

[0028] The speed regulating component 7 is ingeniously integrated into a specific position in the first air passage 614, mainly composed of turbine blades 71 and guide plates 72. The first air passage 614 is designed with an L-shaped configuration, including a vertical section and a horizontal section. The speed regulating component 7 is located near the corner of this passage, a region where the gas flow direction changes and kinetic energy is relatively concentrated, which is conducive to energy transfer. The turbine blades 71 are the core of the speed regulation. They are composed of a set of lightweight, high-strength blades mounted on a rotating shaft. This rotating shaft is axially connected to the housing 611 of the adjusting part through a bearing, allowing the turbine blades 71 to rotate freely in the airflow. The function of the turbine blades 71 is to effectively convert the pressure energy and part of the kinetic energy of the gas into their own rotational mechanical energy. The blades begin to rotate at high speed under the impact of the airflow, according to the fluid force... According to the principle, the rotating blades do work on the gas flowing through them, transferring their own rotational kinetic energy back to the gas, actively increasing the speed and kinetic energy of the gas flowing through the cross section. This allows for a higher output gas velocity and flow rate under the same input gas source conditions, directly converting into a stronger and faster injection speed, which is especially beneficial for filling large, complex, or thin-walled castings. The guide plate 72 is a fixedly installed guide plate tilted at a specific angle. It is located on the side of the turbine blade 71 away from the outlet of the first air passage 614. It rectifies and guides the slightly turbulent gas flowing from the first air intake passage 612 after passing the corner, so that it concentrates its impact on the turbine blade 71 from the upper left side (i.e., closer to the outer edge of the blade and the rotational tangential direction), causing it to rotate counterclockwise.

[0029] The pressure regulating component 8 mainly consists of two core components: a moving rod 81 and a drive wheel 82. These two components work together. The moving rod 81 is a precision-machined rod-shaped component that runs through and can slide axially within the drive section 6181 and the pressurizing section 6182. At its end near the drive wheel 82, it has a semi-circular protrusion 811, which serves as the contact part with the drive wheel 82. The drive wheel 82 is a wheel-shaped component with a special profile, consisting of at least four specific working surfaces and a smooth transition surface 825 connecting them. The four working surfaces are the first working surface 821, the second working surface 822, the third working surface 823, and the fourth working surface 824. The theoretical distances from these four working surfaces to the rotation center of the drive wheel 82 are all different, and their differences are designed to increase in an arithmetic progression. This means that when the same phase point of the drive wheel 82 contacts these four working surfaces sequentially, it will push the moving rod 81 to four different axial positions, generating four long... The driving wheel 82, driven by a micro stepper motor or servo motor through the control system 9, rotates at a constant speed or intermittently according to instructions to achieve multi-level pressure preset and selection. The smooth transition surface 825 connects any two adjacent working surfaces (such as 821 and 822). Its contour curve is carefully designed so that when the driving wheel 82 rotates and the contact point switches from one working surface to the next, the contact point between the protrusion 811 and the contour of the driving wheel 82 will slide smoothly along the smooth transition surface 825. During this sliding process, the displacement applied to the moving rod 81 by the driving wheel 82 remains unchanged, so that the axial position (i.e., the driving stroke) of the moving rod 81 remains constant for a period of time. This ensures that the opening of the pressure regulating component 8 is absolutely fixed during each pressure level and is not affected by the rotation process of the driving wheel 82. This ensures the stability of the holding pressure during this period of time without any fluctuation, which is the key to obtaining a uniform and dense casting structure. In this embodiment, the moving rod 81 located in the drive section 6171 is also provided with a light spring, which enables the moving rod 81 to have a self-resetting effect under the action of the light spring.

[0030] Based on the four arithmetically increasing working surfaces, the geometric features of the drive wheel 82 are further defined. The central angles (i.e., the angles occupied by each working surface on the circumference of the drive wheel) of the first working surface 821, the second working surface 822, the third working surface 823, and the fourth working surface 824 are all equal. This means that the drive wheel 82 is driven by the motor to rotate at a constant speed, so the time that the protrusion 811 stays on each working surface is exactly the same. This pressure step with equal time intervals makes the process programming extremely simple and intuitive, and is conducive to more scientific and uniform pressure compensation for the solidification process of castings of different thicknesses. The smooth transition surface 825 connecting any two adjacent working surfaces (such as 821 and 822) is not an arbitrary curve, but is designed to be tangent to the two working surfaces it connects to. That is, at the connection point between the smooth transition surface 825 and the working surface, the tangent directions of the two are consistent, ensuring that the contour is smooth and continuous at that point, without any angles or inflection points, which also means eliminating possible minor impacts or vibrations.

[0031] The branch section 62 mainly includes a branch section housing 621 and a branch section switching block 622 installed inside it. The branch section housing 621 is a hollow cavity with an inlet end on its outer circumference that is connected to the gas generating equipment (such as an air compressor and air tank system) through a pipeline, serving as the main gas inlet. There are two outlet ends that respectively deliver gas to different gas paths of the regulating section 61. The center lines of the two outlet ends are arranged at a 90° angle. The branch section switching block 622 is rotatably installed in the hollow cavity inside the branch section housing 621. Its position can be precisely controlled by the control system 9 through a miniature rotary drive device (such as a servo motor). Its core function is to realize the "three-state" mechanical switching of the gas path. Injection state: The control system 9 drives the branch switching block 622 to rotate. At this time, the outlet end connected to the first air inlet channel 612 is open to air, while the outlet end connected to the second air inlet channel 615 is blocked. Gas can only enter the injection air path, and high-pressure gas only goes to the injection air path. The gas pushes open the first plug 6121, and after being accelerated by the speed regulating component 7, it pushes the piston of the drive cylinder 5 at high speed to complete the injection. The mechanical sealing ensures that the pressure holding air path is absolutely physically isolated during injection, with no possibility of leakage, and ensures that all gas energy is used for high-speed filling. Pressure holding state: The control system 9 drives the branch switching block 622 to rotate a certain angle, and the outlet end connected to the second air intake channel 615 is ventilated, while the outlet end connected to the first air intake channel 612 is blocked. Gas can only enter the pressure holding air passage. The pressure regulating component 8 starts to work, precisely adjusts and quickly establishes a high pressure holding pressure. Pressure Holding / Stop Intake State: When the system enters the pressure holding stage, and the rear chamber of the drive cylinder 5 is filled with gas and the gas pressure is sufficient to maintain the current compensation pressure, in order to save energy and prevent excessive pressure, the control system 9 can drive the branch switching block 622 to rotate a small angle. The outlet end connected to the second intake channel 615 is blocked, and the outlet end connected to the first intake channel 612 is also blocked, completely cutting off the continuous gas supply from the main gas source. Cutting off the main gas source avoids the continuous work of the gas generating equipment and the continuous flow loss of the pipeline, significantly reducing the energy consumption of the equipment. At the same time, it also isolates the interference of pressure pulsation that may exist in the remote gas source on the pressure holding pressure. It also makes the drive cylinder 5, the connecting pipeline and the second gas chamber 617 form a closed high-pressure gas capacity system. Thereafter, the pressure maintenance and micro-compensation of the pressure holding process are completely controlled by the precision mechanical movement of the pressure regulating component 8, thereby ensuring the optimization of the melt solidification compensation process.

[0032] The branch switching block 622 is a cylindrical component that can rotate on the branch section housing 621. Three independent third plugs 6221, fourth plug 6222, and fifth plug 6223 are arranged on its outer circumference. These three plugs are not uniformly distributed; the angle between their centerlines is precisely calculated to achieve a specific switching logic. The centerlines of the third plug 6221 and the fourth plug 6222 form a 115° angle, and the centerlines of the fourth plug 6222 and the fifth plug 6223 form a 38° angle. This forms the geometric basis for achieving the three-state switching of "injection," "holding pressure," and "cutoff." The branch switching block 622 is controlled by the control system 9 through a drive mechanism (such as a servo motor) to rotate to three specific angular positions: Injection stage angle: When the switching block is rotated to this position, the fourth plug 6222 is tightly sealed on the outlet end connected to the pressure-holding gas circuit. At this time, the third plug 6221 and the fifth plug 6223 are both in an misaligned state and do not block any outlet end. The main gas source gas can only flow out from the outlet end matched with the injection gas circuit. During the pressure holding stage: The control system drives the branch switching block 622 to rotate (e.g., rotate counterclockwise 25°) to the next position. At this time, the third plug 6221 rotates into place and tightly seals the outlet end that matches the injection gas circuit. The fourth plug 6222 and the fifth plug 6223 are both in an misaligned state and do not seal any outlet end. The main gas source gas can only flow out from the outlet end that matches the pressure holding gas circuit. Stop air intake stage angle: When the system determines that the gas volume has met the pressure holding requirements, the control system drives the branch switching block 622 to rotate a small angle (for example, 13° clockwise). At this position, the third plug 6221 and the fifth plug 6223 simultaneously block the corresponding two air outlets, while the fourth plug 6222 is in the idle position. In this state, the two air outlets are mechanically blocked at the same time, and the main air source supply is completely cut off.

[0033] Meanwhile, to ensure absolute sealing and long service life, each plug (6221, 6222, 6223) is fitted with a sealing rubber head 6224 at its end. This rubber head is made of oil-resistant, high-temperature-resistant, and highly elastic materials (such as polyurethane or fluororubber). The key design lies in the difference in its length. The sealing rubber head of the third plug 6221 is longer than that of the fourth plug 6222 and the fifth plug 6223. The sealing rubber head of the fourth plug 6222 and the fifth plug 6223 are of equal length, ensuring the absolute reliability of the "double sealing" state. The longer sealing rubber head means that a wider sealing contact band can be generated under the same driving displacement, ensuring the complete cutoff of the main air source when both air outlets are blocked at the same time, and ensuring the normal operation of pressure holding.

[0034] The control system 9 includes a human-machine interaction module 91, a logic control module 92, a regulation module 93, and a signal acquisition module 94. The human-machine interaction module 91 is electrically connected to the logic control module 92. The logic control module 92 is electrically connected to the regulation module 93 and the signal acquisition module 94. The regulation module 93 is electrically connected to the pressure regulating component 8 and the branch circuit 62. The signal acquisition module 94 is electrically connected to the cavity pressure sensor installed in the mold closing mechanism 2 and / or the position sensor connected to the drive cylinder 5. The human-machine interaction module 91 is used to set process parameters and display equipment status. Its setting parameters include the switching pressure threshold between the injection stage and the holding stage, the holding pressure setting value, and the holding time. The signal acquisition module 94 is used to acquire the cavity pressure signal fed back by the cavity pressure sensor and / or the screw displacement signal fed back by the position sensor in real time, and transmit the signal to the logic control module 92. The logic control module 92 includes a stage judgment unit 921 and an instruction generation unit 922. The stage judgment unit 921 is used to continuously compare the real-time data fed back by the signal acquisition module 94 with the preset switching threshold. When the real-time cavity pressure reaches the switching pressure threshold or the real-time feed screw displacement reaches the preset position, it is determined that the melt is full and a switching signal from the injection stage to the holding pressure stage is generated. The instruction generation unit 922 is used to generate a corresponding combination of control instructions according to the current stage state: In the injection stage, the control branch 62 is converted to the state of supplying gas to the injection gas path. After the injection is completed and the switching signal is received, the control branch 62 is immediately converted to the state of switching to supplying gas to the holding pressure gas path and closing the supply of gas to the injection gas path. After the gas supply in this stage is completed and the switching signal is received, the control branch 62 is converted to the state of simultaneously stopping the gas intake of the two gas paths and controlling the pressure regulating component 8 to start increasing the output gas pressure. The control module 93 directly receives and executes the control commands issued by the logic control module 92. It includes a first drive unit 931 and a second drive unit 932. The first drive unit 931 is electrically connected to the branch section 62 and is used to control the selective conduction of one of the two air passages in the branch section 62 or the non-conduction of both air passages. The second drive unit 932 is electrically connected to the pressure regulating component 8 and is used to control the gas pressure output to the drive cylinder 5.

[0035] Step 1: System Initialization and Process Parameter Setting Equipment preparation: Start the main power supply of the equipment, the air generating equipment (air compressor) starts to work, and establishes a stable main air source pressure for the system. Mechanical parts such as mold closing mechanism 2, drive mechanism 3, and screw feeding mechanism 4 complete self-check and reset. Process programming: Operators input or call up the process formula for this production task through the human-machine interface module 91 (touch screen). Key parameters include: injection stage target, i.e., preset injection speed (indirectly corresponding to the gas flow rate required to drive cylinder 5); switching conditions: setting the cavity pressure threshold and / or feed screw termination position to trigger the switch from the injection stage to the holding stage; holding stage target: setting the target value of holding pressure and holding time, or selecting a preset multi-stage holding curve (e.g., 120MPa held for 3s → 100MPa held for 2s → 80MPa held for 2s). Parameter distribution: The set parameters are sent to the logic control module 92 (PLC) through the human-machine interaction module 91, and become the control logic reference for this cycle.

[0036] Step 2: Mold Closure and Melt Preparation Mold closing: The logic control module 92 instructs the drive mechanism 3 to act, driving the mold closing mechanism 2 to tightly close the mold, forming a sealed casting cavity; Melt conveying and accumulation: The screw feeder 4 is started, and its feeding screw rotates to convey and accumulate the near-liquid phase semi-solid melt from the previous melting and holding furnace in the storage chamber at its front end. Step 3: Injection Stage – High-Speed ​​Filling Command issuance and gas path switching: When the melt accumulation reaches the set value, the command generation unit 922 of the logic control module 92 issues a "start injection" command, and the first drive unit 931 of the control module 93 immediately drives the branch switching block 622 of the branch section 62 to rotate to the "injection position". At this time, the main gas source gas can only flow through the branch section 62 to the first air inlet channel 612 (injection gas path) of the regulating section 61, while the interface leading to the pressure holding gas path is mechanically blocked. Gas acceleration and high-speed drive: High-pressure gas pushes open the first plug 6121 in the regulating part 61 and enters the first air passage 614. When it flows through the speed regulating component 7 (such as turbine blade 71), the gas is actively accelerated and obtains extremely high flow rate and flow rate. Then, the gas rushes into the rear chamber of the drive cylinder 5 through the exhaust passage 618. Injection execution: Driven by high-pressure, high-speed gas, the piston of the drive cylinder 5 drives the feeding screw to rush forward rapidly, injecting the melt in the storage chamber into the mold cavity at extremely high speed.

[0037] Real-time monitoring and intelligent judgment: During this process, the signal acquisition module 94 continuously acquires the pressure sensor signals installed in the mold cavity and / or the position sensor signals linked to the feeding screw, and transmits them to the logic control module 92. The stage judgment unit 921 continuously compares the real-time pressure with the preset data.

[0038] Step 4: Intelligent Stage Switching – From Injection to Pressure Holding Triggering switching: When the real-time cavity pressure reaches the threshold (indicating that the melt has completely filled the cavity and started to build up pressure), the stage judgment unit 921 immediately generates a high-priority switching signal.

[0039] Millisecond-level response and hard switching: Within milliseconds of receiving the signal, the instruction generation unit 922 issues a new combination of instructions. The first drive unit 931 drives the branch switching block 622 to rotate rapidly (e.g., 25°) to the "pressure holding position". This action completely cuts off the gas to the injection gas path and simultaneously opens the passage to the second air intake channel 615 (pressure holding gas path) of the regulating unit 61. The injection action is forcibly terminated and the pressure holding stage begins immediately.

[0040] Step 5: Pressure Holding Stage – Precision Compensation High pressure establishment and active isolation: The main gas source gas is switched to the pressure-maintaining gas path, which opens the second plug 6151. At the same time, the linkage design of the second plug 6151 causes its valve stem to be inserted synchronously and block the first gas passage 614, realizing hard isolation of the two gas paths. The gas enters the second gas chamber 617 of the regulating part 61. Constructing a closed pressure-holding system (key energy-saving and precision control steps): When the pressure sensor reports that the pressure has reached the preset value or after a short period of stable inflation time, the logic control module 92 instructs the branch switching block 622 to rotate to the "cut-off position". The third plug 6221 and the fifth plug 6223 simultaneously block the two air outlets of the branch section 62, actively cutting off the continuous air supply from the main air source. Thus, the drive cylinder 5, pipeline and the pressure-holding air circuit of the regulating section together form a closed high-pressure air capacity system isolated from the outside world. Precision pressure compensation within a closed system: In a closed environment free from external interference, the pressure regulating component 8 begins to perform its precision control function. The second drive unit 932 controls the drive wheel 82 to rotate at a constant speed according to the preset pressure holding setting. Through the precision micro-motion of the moving rod 81 (driven by the drive wheel 82 with equal working surfaces and smooth transition surfaces), the effective volume or throttling state within the closed system is finely adjusted, thereby achieving nanometer-level fine adjustment of the pressure holding pressure. This allows the piston rod of the drive cylinder 5 to move forward slightly at an extremely slow, stable, and programmable speed, continuously and accurately compensating for the shrinkage of the melt during the solidification process, and effectively expelling shrinkage cavities and porosity defects to the gating system.

[0041] Step 6: End of pressure holding and subsequent processing Pressure holding complete: When the set pressure holding time is reached or the multi-stage pressure holding is completed, the logic control module 92 determines that the pressure holding stage has ended; Pressure relief and mold opening: The control system commands the relevant exhaust valve to open, releasing the gas pressure in the drive cylinder 5 and pipeline. Subsequently, it commands the drive mechanism 3 to operate and open the mold closing mechanism 2. Ejection and Removal: The ejection mechanism ejects the molded casting from the mold, where it is removed by a robot or operator; System reset: The feeding screw of the screw feeder mechanism 4 rotates and resets, ready to receive the melt of the next cycle. The plugs in the branch section 62 and the adjustment section 61 are reset under the action of the spring, and the entire system returns to the initial state, waiting for the command to start the next cycle.

[0042] The above workflow clearly demonstrates how the device of the present invention intelligently commands the gas path distribution and switching mechanism and the pressure precision adjustment mechanism to work together through real-time processing of sensor signals by the control system. It achieves adaptive and precise switching, and the "high-speed injection" and "high-pressure low-speed holding" are perfectly realized through proprietary gas paths and mechanisms. The "actively cut off the gas source and finely adjust the closed system" mode during the holding stage isolates external interference, significantly reduces energy consumption, and provides a reliable system guarantee for the production of high-quality, highly consistent near-liquidline extrusion castings.

[0043] Although the present invention has been illustrated and described with reference to preferred embodiments, those skilled in the art will understand that various changes in form and detail are possible within the scope of the claims.

Claims

1. A near-liquidline extrusion casting molding equipment, comprising a support (1), a mold closing mechanism (2) provided on the support (1), a drive mechanism (3) connected to the mold closing mechanism (2) on one side to drive the mold closing mechanism (2) to open or close the mold, and a screw feeding mechanism (4) connected to the mold closing mechanism (2) on the other side, characterized in that: The spiral feeding mechanism (4) is provided with a driving cylinder (5) on the side away from the connection between it and the mold clamping mechanism (2). The driving cylinder (5) is provided with an adjustment mechanism (6) that can control the gas flow rate and gas pressure. When the melt has not filled the mold clamping mechanism (2) during the injection stage, the adjustment mechanism (6) increases the gas flow rate to make the feeding screw rush forward at high speed to inject the melt into the mold clamping mechanism (2). When the melt has filled the mold clamping mechanism (2) during the pressure holding stage, the adjustment mechanism (6) reduces the gas flow rate and increases the gas pressure to make the feeding screw move forward slightly to compensate for the shrinkage of the melt. The adjustment mechanism (6) is controlled by the control system (9). The control system (9) is used to automatically switch the working state of the adjustment mechanism (6) during the injection stage or the pressure holding stage.

2. The near-liquidline extrusion casting equipment according to claim 1, characterized in that: The regulating mechanism (6) includes an regulating section (61) and a branch section (62). The regulating section (61) has two air passages, and the two air passages do not flow at the same time. One air passage flows when the melt has not filled the mold closing mechanism (2) during the injection stage, and the other air passage flows when the melt has filled the mold closing mechanism (2) during the pressure holding stage. The branch section (62) delivers the gas supplied by the gas generating equipment into the regulating section (61) and can match the selective air supply of the regulating section (61), or prevent gas from entering when the gas quantity is sufficient to push the drive cylinder (5) to move.

3. The near-liquidline extrusion casting equipment according to claim 2, characterized in that: The adjusting part (61) includes an adjusting part housing (611), and a first air inlet channel (612), a first air chamber (613), a first air outlet channel (614), a second air inlet channel (615), a second air outlet channel (616), a second air chamber (617), and an air outlet channel (618) formed within the adjusting part housing (611). The first air inlet channel (612), the first air chamber (613), the first air outlet channel (614), the second air chamber (617), and the air outlet channel (618) constitute an injection air outlet path, and the second air inlet channel (615), the second air outlet channel (616), the second air chamber (617), and the air outlet channel (618) constitute a pressure-holding air outlet path. The first air inlet channel (612) is provided with a force-applying mechanism via an elastic member. A first plug (6121) is used to block the inlet of the first air chamber (613). A second plug (6151) is provided in the second air inlet channel (615) to block the inlet of the second air outlet channel (616) by applying force through an elastic component. When the second plug (6151) releases the blockage of the inlet of the second air outlet channel (616), it also simultaneously blocks the first air outlet channel (614). After blocking, the amount of gas entering the second air chamber (617) through the second air outlet channel (616) can be reduced. A speed regulating component (7) that can increase the gas flow rate and velocity is provided near the inlet of the first air outlet channel (614). A pressure regulating component (8) that can increase the gas pressure is provided in the second air chamber (617).

4. The near-liquidline extrusion casting equipment according to claim 3, characterized in that: The second air chamber (617) includes a drive section (6171) and a pressurization section (6172). The drive section (6171) is used to set the pressure regulating member (7). Part of the space of the pressurization section (6172) is used to receive the gas delivered by the first air passage (614) during the injection stage and to receive the gas delivered by the second air passage (616) during the pressure holding stage. The other part of the space is used as the activity space of part of the pressure regulating member (7).

5. The near-liquidline extrusion casting equipment according to claim 3, characterized in that: The speed regulating component (7) includes a turbine blade (71) and a guide plate (72). The first air passage (614) has an L-shaped configuration, and the turbine blade (71) is arranged at a position close to its vertical section in its horizontal section. The guide plate (72) is located on the side of the turbine blade (71) away from the outlet of the first air passage (614) and is inclined, so that the gas contacts the turbine blade (71) at a position slightly to the left of the turbine blade (71) through the guide plate (72).

6. The near-liquidline extrusion casting equipment according to claim 4, characterized in that: The pressure regulating component (8) includes a moving rod (81) and a drive wheel (82) for driving the moving rod (81) to move. The moving rod (81) moves simultaneously within the drive section (6181) and the pressurizing section (6182) and has a semi-circular protrusion (811) at one end near the drive wheel (82). The profile of the drive wheel (82) includes at least four working surfaces, namely a first working surface (821), a second working surface (822), a third working surface (823), and a fourth working surface (824). When the drive wheel (82) rotates at a constant speed around its central axis, it can sequentially drive the moving rod (81) to generate four different propulsion strokes. The lengths of the four propulsion strokes are in an arithmetic progression relationship. The working surfaces of two adjacent drive wheels are connected by a smooth transition surface (825). The smooth transition surface (825) contacts the moving rod (81) when two adjacent cam working surfaces transition from one to the other, so that the propulsion stroke remains constant.

7. The near-liquidline extrusion casting equipment according to claim 6, characterized in that: The central angles of the four working surfaces around the central axis are all equal, and the outline of the smooth transition surface (825) is tangent to the two adjacent cam working surfaces.

8. The near-liquidline extrusion casting equipment according to claim 2, characterized in that: The branch section (62) includes a branch section housing (621) and a branch switching block (622) rotatably disposed within the branch section housing (621). The branch section housing (621) is hollow inside and has one air inlet and two air outlets communicating with the hollow part on its outer circumference. The air inlet is used to connect to the gas generating equipment pipe. The center lines of the two air outlets are arranged at a 90° angle. One air outlet is connected to a pipe connector at the air inlet of the first air inlet channel (612), and the other air outlet is connected to a pipe connector at the air inlet of the second air inlet channel (615). During the injection stage, the branch switching block (622) blocks the outlet end connected to the pressure-holding gas pipeline but does not block the outlet end connected to the injection gas pipeline. Conversely, during the pressure-holding stage, it blocks the outlet end connected to the injection gas pipeline but does not block the outlet end connected to the pressure-holding gas pipeline. When the gas volume is sufficient to push the drive cylinder (5) to move, the branch switching block (622) blocks both outlet ends to stop the gas intake. Then, the pressure is increased by the pressure regulating movement of the pressure regulating component (8) to achieve the slow advancement of the piston rod of the drive cylinder (5).

9. The near-liquidline extrusion casting equipment according to claim 8, characterized in that: The outer peripheral surface of the branch switching block (622) is provided with a third plug (6221), a fourth plug (6222), and a fifth plug (6223). The center lines of the third plug (6221) and the fourth plug (6222) are arranged at an angle of 115°, and the center lines of the fourth plug (6222) and the fifth plug (6223) are arranged at an angle of 38°. During the injection stage, the fourth plug (6222) is sealed at the corresponding air outlet, while the third plug (6221) and the fifth plug (6223) are not sealed at their respective air outlets. During the pressure holding stage, when the third plug (6221) is sealed at the corresponding air outlet, the fourth plug (6222) and the fifth plug (6223) are not sealed at their respective air outlets. The head (6223) is not blocked at the corresponding air outlet. When the gas volume is sufficient to push the drive cylinder (5) to move, the third plug (6221) and the fifth plug (6223) are both blocked at the corresponding air outlet. The ends of the third plug (6221), the fourth plug (6222), and the fifth plug (6223) are all fitted with sealing rubber heads (6224). The length of the sealing rubber head (6224) of the third plug (6221) is greater than the length of the sealing rubber head (6224) of the fourth plug (6222) and the fifth plug (6223). The lengths of the sealing rubber head (6224) of the fourth plug (6222) and the fifth plug (6223) are equal.

10. The near-liquidline extrusion casting equipment according to claim 2, characterized in that: The control system (9) includes a human-machine interaction module (91), a logic control module (92), a regulation module (93), and a signal acquisition module (94). The human-machine interaction module (91) is electrically connected to the logic control module (92). The logic control module (92) is electrically connected to the regulation module (93) and the signal acquisition module (94). The regulation module (93) is electrically connected to the pressure regulating component (8) and the branch section (62). The signal acquisition module (94) is electrically connected to the cavity pressure sensor disposed in the mold closing mechanism (2) and / or the position sensor connected to the drive cylinder (5). The human-machine interaction module (91) is used to set process parameters and display equipment status. Its setting parameters include the switching pressure threshold between the injection stage and the holding stage, the holding pressure setting value, and the holding time. The signal acquisition module (94) is used to acquire the cavity pressure signal fed back by the cavity pressure sensor and / or the screw displacement signal fed back by the position sensor in real time, and transmit the signal to the logic control module (92). The logic control module (92) includes a stage judgment unit (921) and an instruction generation unit (922). The stage judgment unit (921) is used to continuously compare the real-time data fed back by the signal acquisition module (94) with the preset switching threshold. When the real-time cavity pressure reaches the switching pressure threshold or the real-time feed screw displacement reaches the preset position, it is determined that the melt is full and a switching signal from the injection stage to the holding pressure stage is generated. The instruction generation unit (922) is used to generate a corresponding combination of control instructions according to the current stage state: In the injection stage, an instruction is generated to control the branch section (62) to switch to the state of sending gas to the injection gas path. After the injection is completed and the switching signal is received, an instruction is immediately generated to control the branch section (62) to switch to the state of sending gas to the holding pressure gas path and to close the gas path for injection. After the gas is sent in this stage and the switching signal is received, an instruction is generated to control the branch section (62) to switch to the state of sending gas to the holding pressure gas path and to close the gas path for injection. After the gas is sent in this stage and the switching signal is received, an instruction is generated to control the branch section (62) to switch to the state of stopping the gas intake of the two gas paths at the same time and to control the pressure regulating component (8) to start increasing the output gas pressure. The control module (93) directly receives and executes the control commands issued by the logic control module (92). It includes a first drive unit (931) and a second drive unit (932). The first drive unit (931) is electrically connected to the branch section (62) and is used to control the selective conduction of one of the two air passages of the branch section (62) or the non-conduction of both air passages. The second drive unit (932) is electrically connected to the pressure regulating component (8) and is used to control the gas pressure output to the drive cylinder (5).

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