Hydraulic transmission control system for vertical press and vertical press

Abstract

The invention belongs to the technical field of hydraulic pressure of injection molding machines, and provides a hydraulic transmission control system for a direct pressing machine and the direct pressing machine. The mold locking loop comprises an active safety valve, an electro-hydraulic directional control valve, a piston control assembly and a first cartridge valve; the piston control assembly is composed of a first electromagnetic reversing valve, a first poppet valve and a piston. The mold locking high-pressure loop consists of a second electromagnetic directional valve and a first one-way valve; the pressure relief loop is composed of a second poppet valve and a first one-way throttling valve, and the pressure relief flow is controlled by adjusting the size of a throttling opening; the glue injection loop is used for controlling the glue density through the melt glue back pressure and executing the glue injection action; and the first cartridge valve is opened and closed by a third electromagnetic directional valve control valve core. Compared with the prior art, the independent pressure relief loop is arranged, and the adjustable first one-way throttle valve is adopted, so that pressure relief impact is effectively reduced, and the abnormal vibration risk of the template is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydraulic technology of injection molding machine, and particularly relates to a hydraulic transmission control system for a direct pressure machine and the direct pressure machine. BACKGROUND

[0002] In the field of injection molding, the direct pressure machine plays an important role due to its unique advantages. In terms of structure, the direct pressure machine has simple and reliable mechanical structure and low maintenance cost in later period; in terms of performance, the direct pressure machine has uniform and precise control of mold clamping force distribution, easy mold thickness adjustment and large mold capacity. Therefore, the direct pressure machine is suitable for injection molding production of high-precision products, products with relatively thick molds and deep cavity products.

[0003] However, the traditional direct pressure machine has the following problems: when the mold is locked at high pressure, the pressure fluctuates sharply during pressure relief, forming a pressure relief impact, which may cause the mold plate to vibrate; the system oil supply needs to pass through the active safety valve, which causes the active safety valve to be powered for a long time during the whole mold locking process (fast mold opening and closing, high-pressure mold locking, piston control, etc.), and the service life is relatively short; the system pressure may be left over during shutdown maintenance, which has safety hazards.

[0004] Therefore, an improved hydraulic transmission control system is needed to solve the above problems. SUMMARY

[0005] The present application solves the technical problems of the prior art and provides a hydraulic transmission control system for a direct pressure machine and the direct pressure machine.

[0006] The technical solution adopted by the present application to solve the above technical problems is as follows: a hydraulic transmission control system for a direct pressure machine is provided, the direct pressure machine includes a direct fast oil cylinder and a plunger cylinder, and the hydraulic transmission control system includes: a mold locking loop for controlling the direct fast mold opening and closing speed and locking the mold at a set pressure; the mold locking loop includes an active safety valve, an electro-hydraulic reversing valve, a piston control assembly and a first cartridge valve; the B port and the T port of the active safety valve are connected to the system oil supply, the A port and the P port of the active safety valve are connected to the P port of the electro-hydraulic reversing valve; the A port of the electro-hydraulic reversing valve is connected to the rodless cavity of the direct fast oil cylinder, the B port of the electro-hydraulic reversing valve is connected to the rod cavity of the direct fast oil cylinder, and the T port of the electro-hydraulic reversing valve is connected to the oil tank through the first cartridge valve; the piston control assembly is composed of a first electromagnetic reversing valve, a first poppet valve and a piston, and is used for controlling the on-off of the high-pressure cavity of the plunger cylinder and the oil tank; a mold locking high-pressure loop composed of a second electromagnetic reversing valve and a first check valve, in which oil directly enters the high-pressure cavity of the plunger cylinder; a pressure relief loop composed of a second poppet valve and a first check throttle valve, in which the pressure relief flow is controlled by adjusting the size of the throttle port; a glue injection loop for controlling the glue density by glue back pressure and executing glue injection action; The first plug valve is controlled by the third electromagnetic reversing valve to open and close the valve core; When the third electromagnetic reversing valve is not powered, the first plug valve core is opened, and the rod cavity of the oil cylinder has no back pressure; When the third electromagnetic reversing valve is powered, the first plug valve core is closed or generates back pressure, which is used for slow mold closing or mold opening buffer.

[0007] In the hydraulic transmission control system for the straight press, in the mold locking circuit, the oil supply of the high-pressure mold locking and piston control does not pass through the active safety valve, so that the active safety valve is only powered during the straight fast mold opening and closing.

[0008] In the hydraulic transmission control system for the straight press, the first one-way throttle valve in the pressure relief circuit can adjust the opening degree of the throttle, which is used to control the flow when the plunger cylinder is relieved.

[0009] In the hydraulic transmission control system for the straight press, the first plug valve is normally open with zero back pressure, and the system pressure is released through the first plug valve when the machine is stopped.

[0010] In the hydraulic transmission control system for the straight press, the injection circuit comprises: The injection cylinder control module switches the injection / retreat action through the fourth electromagnetic reversing valve; The melt back pressure module adjusts the opening pressure of the second plug valve by the proportional back pressure valve; The injection displacement cylinder control module executes the injection seat advance and retreat action through the fifth electromagnetic reversing valve.

[0011] In the hydraulic transmission control system for the straight press, when the second electromagnetic reversing valve is powered, the pressure oil flows through it to the first one-way valve and enters the high-pressure cavity of the plunger cylinder, realizing high-pressure mold locking; When the first electromagnetic reversing valve and the first poppet valve are not powered, the piston moves to the right under the action of the spring force and forms a linear seal with the plunger cylinder body, isolating the high-pressure cavity from the oil tank.

[0012] In the hydraulic transmission control system for the straight press, when the second poppet valve is powered, it conducts the oil circuit between the high-pressure cavity of the plunger cylinder and the first one-way throttle valve, so that the high-pressure oil slowly returns to the oil tank through the throttle.

[0013] In the hydraulic transmission control system for the straight press, in the melt back pressure module, the proportional back pressure valve sets the pressure as the pilot control pressure of the second plug valve, adjusts the backflow resistance to control the backflow pressure of the melt motor.

[0014] In the hydraulic transmission control system for the direct press, the direct quick oil cylinder adopts a differential connection mode during quick mold closing, that is, the oil in the rod cavity flows into the rodless cavity through the second check valve to realize high-flow quick advance; during slow mold closing or mold opening, the oil in the rod cavity returns to the oil tank through the electro-hydraulic reversing valve and the first cartridge valve.

[0015] The present application also provides a direct press comprising the above-mentioned hydraulic transmission control system for the direct press.

[0016] Compared with the prior art, the present application has the following advantages:

[0017] (1) By setting an independent pressure relief circuit and using an adjustable first check throttle valve, the pressure relief impact is effectively reduced, and the risk of abnormal mold vibration is reduced; by setting an independent mold locking high-pressure circuit, the high-pressure oil supply bypasses the active safety valve, significantly prolonging its service life; at the same time, by designing the first cartridge valve to be normally open, the system pressure can be automatically released, improving the safety of maintenance and debugging. The overall structure of the system is reasonable, the functional modules are clear, the control is precise, and it is suitable for stable production of high-precision, thick mold and deep cavity products.

[0018] (2) By decoupling the high-pressure mold locking and piston control oil circuit from the active safety valve, only during the direct quick mold opening and closing stage is the valve controlled to open and close the main oil circuit, and in other working conditions, the valve is in a power-off pressure maintaining state, which fundamentally reduces the working load and power-on time of the valve. This not only effectively avoids the performance degradation caused by long-term power-on and high-pressure load, but also significantly prolongs the service life of the active safety valve and reduces the equipment failure rate and maintenance cost.

[0019] (3) By adjusting the opening degree of the first check throttle valve, the pressure relief rate of the plunger cylinder high-pressure cavity can be accurately controlled, and the traditional instantaneous high-pressure release is changed into a controllable gradual pressure relief process. This design effectively suppresses the severe pressure fluctuations during the pressure relief process, significantly reduces the hydraulic impact force, effectively suppresses the abnormal vibration of the mold caused by sudden pressure drop, avoids structural fatigue damage, and improves the stability and reliability of the equipment operation.

[0020] (4) The first cartridge valve remains open in the power-off state, and the oil circuit of the rod cavity of the direct quick oil cylinder is directly connected to the oil tank. This design ensures that during equipment shutdown, maintenance or debugging, the residual pressure in the system can be continuously discharged through this path, completely eliminating the hidden danger of pressure accumulation in the hydraulic circuit. When operating personnel are disassembling oil pipes or replacing components, they no longer face the risk of sudden spraying of high-pressure oil, significantly improving the safety of the operation process.

[0021] (5) The second poppet valve opens the pressure relief channel after being powered, and the high-pressure oil in the plunger cylinder high-pressure cavity must be discharged to the oil tank through the adjustable first one-way throttle valve, forming a double buffering mechanism of "pilot control + throttle regulation". This design further enhances the controllability of the pressure relief process, making the pressure drop more gentle, effectively suppressing the pressure impact and vibration of the hydraulic system, and improving the smoothness of the equipment in high-pressure switching conditions. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1 is a schematic diagram of a hydraulic transmission control system for a direct pressure machine.

[0023] Fig. 2 is a hydraulic principle diagram of the mold locking circuit.

[0024] Fig. 3 is a hydraulic principle diagram of the glue injection circuit.

[0025] In the figure, 201 is a piston, 202 is a first poppet valve, 203 is a first one-way valve, 204 is a first one-way throttle valve, 205 is a first electromagnetic directional valve, 206 is a second poppet valve, 207 is a second electromagnetic directional valve, 208 is a main safety valve, 209 is a plunger cylinder, 210 is a direct quick oil cylinder, 211 is an electro-hydraulic directional valve, 212 is a first cartridge valve, 213 is a third electromagnetic directional valve, 214 is a second one-way valve, 301 is a fourth electromagnetic directional valve, 302 is a fifth electromagnetic directional valve, 303 is a proportional back pressure valve, and 304 is a second cartridge valve. DETAILED DESCRIPTION

[0026] The following is a specific embodiment of the present application and further describes the technical solutions of the present application in conjunction with the drawings, but the present application is not limited to these embodiments.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0028] As shown in Figs. 1 to 3 , a hydraulic transmission control system for a direct pressure machine, the direct pressure machine includes a direct quick oil cylinder 210 and a plunger cylinder 209, the direct quick oil cylinder 210 is used to control the direct quick mold opening and closing action, and the plunger cylinder 209 is used to realize the high-pressure mold locking action, the hydraulic transmission control system includes: a mold locking circuit, a mold locking high-pressure circuit, a pressure relief circuit, and a glue injection circuit.

[0029] The mold locking loop is used to control the speed of the straight fast mold opening and closing, and lock the mold at a set pressure and keep the pressure. The mold locking loop includes an active safety valve 208, an electro-hydraulic reversing valve 211 and a piston control assembly, and a first plug-in valve 212. The B port and the T port of the active safety valve 208 are connected to the system oil supply, and the A port and the P port of the active safety valve 208 are connected to the P port of the electro-hydraulic reversing valve 211. The A port of the electro-hydraulic reversing valve 211 is connected to the rodless cavity of the straight fast oil cylinder 210, the B port of the electro-hydraulic reversing valve 211 is connected to the rod cavity, and the T port of the electro-hydraulic reversing valve 211 is connected to the oil tank through the first plug-in valve 212. The piston control assembly is composed of a first electromagnetic reversing valve 205, a first poppet valve 202 and a piston 201, and is used to control the on-off between the high-pressure cavity of the plunger cylinder 209 and the oil tank.

[0030] The mold locking high-pressure loop is composed of a second electromagnetic reversing valve 207 and a first check valve 203, and the pressure oil directly enters the high-pressure cavity of the plunger cylinder 209 through the loop to realize high-pressure mold locking.

[0031] The pressure relief loop is composed of a second poppet valve 206 and a first one-way throttling valve 204, and the pressure relief flow can be controlled by adjusting the size of the throttling port to realize controllable pressure relief.

[0032] The glue injection loop controls the glue density by adjusting the melt glue back pressure, and completes the glue injection action. The first plug-in valve 212 is controlled by a third electromagnetic reversing valve 213 to open and close the valve core; when the third electromagnetic reversing valve 213 is not powered, the valve core of the first plug-in valve 212 is opened, and the rod cavity of the straight fast oil cylinder returns to the oil tank without back pressure; when the third electromagnetic reversing valve 213 is powered, the valve core of the first plug-in valve 212 is closed or back pressure is generated, which is used for slow mold closing or mold opening buffering.

[0033] In the fast mold closing stage, the first electromagnetic reversing valve 205 and the first poppet valve 202 are powered, the pressure oil enters the oil cavity between the piston 201 and the cylinder wall, pushes the piston 201 to move to the left, and makes the high-pressure cavity of the plunger cylinder 209 communicate with the oil tank. At the same time, the active safety valve 208 is powered, the electro-hydraulic reversing valve 211 is switched to the left position, and the pressure oil enters the rodless cavity of the straight fast oil cylinder 210. At this time, if the third electromagnetic reversing valve 213 is powered, the first plug-in valve 212 is closed, and the oil in the rod cavity of the straight fast oil cylinder 210 flows into the rodless cavity through the second check valve 214 to form a differential connection, realizing fast mold closing with large flow.

[0034] When entering the high-pressure mold locking stage, the first electromagnetic reversing valve 205 and the first poppet valve 202 are powered off, the piston 201 moves to the right under the action of the spring force, forms a linear seal with the plunger cylinder 209, and isolates the high-pressure cavity from the oil tank. Then, the second electromagnetic reversing valve 207 is powered, the pressure oil enters the high-pressure cavity of the plunger cylinder 209 through the valve and the first check valve 203, and pushes the plunger to complete the high-pressure mold locking action. In this process, the high-pressure oil circuit does not pass through the active safety valve 208, and the valve can be powered off, thereby significantly reducing the working load.

[0035] In the pressure relief phase, the second poppet valve 206 is powered on to open the oil path between the plunger cylinder 209 high-pressure cavity and the first one-way throttle valve 204, and the high-pressure oil is slowly discharged back to the tank through the first one-way throttle valve 204. By adjusting the opening degree of the throttle, the pressure relief flow can be accurately controlled to achieve smooth pressure relief, effectively reduce hydraulic impact, and avoid abnormal vibration of the mold plate.

[0036] In the fast mold opening phase, the active safety valve 208 is powered on, and the electro-hydraulic reversing valve 211 is switched to the right position, and the pressure oil enters the rod cavity of the direct quick oil cylinder 210. At this time, if the third electromagnetic reversing valve 213 loses power, the first cartridge valve 212 valve core is in the normal open state, and the rod cavity oil can be returned without back pressure, realizing fast mold opening. In the slow mold closing or mold opening end buffering phase, the third electromagnetic reversing valve 213 is powered on, and the first cartridge valve 212 valve core is closed or generates a certain back pressure, realizing smooth deceleration and avoiding rigid impact.

[0037] The system has significant advantages in safety design. When the third electromagnetic reversing valve 213 loses power in the normal state, the first cartridge valve 212 remains open, the direct quick oil cylinder 210 return oil path is connected with the tank, and the system residual pressure can be automatically released. Therefore, during maintenance or debugging, the system will not be pressurized, greatly improving the safety of the operator. At the same time, the active safety valve 208 is only powered on during the direct quick mold opening and closing process, and does not participate in oil supply during high-pressure locking, piston sealing and pressure relief, so the power-on time is greatly shortened and the service life is significantly prolonged.

[0038] The hydraulic transmission control system effectively reduces the pressure relief impact and reduces the risk of abnormal mold plate vibration by setting an independent pressure relief circuit and using an adjustable first one-way throttle valve 204. By setting an independent locking high-pressure circuit, the high-pressure oil supply bypasses the active safety valve 208, significantly extending its service life. At the same time, through the normal opening design of the first cartridge valve 212, the system pressure can be automatically released, improving the safety of maintenance and debugging. The overall structure of the system is reasonable, the function modules are clear, the control is accurate, and it is suitable for stable production of high-precision, thick mold and deep cavity products.

[0039] In the locking circuit, the high-pressure locking and piston 201 control oil supply do not pass through the active safety valve 208, so that the valve only works in the direct quick mold opening and closing phase.

[0040] The technical scheme sets an independent mold locking high-pressure circuit, which is composed of the second electromagnetic switching valve 207 and the first one-way valve 203, and pressure oil directly enters the plunger cylinder 209 high-pressure cavity through the circuit to complete the high-pressure mold locking action. Meanwhile, the sealing control of the piston 201 is independently driven by the first electromagnetic switching valve 205 and the first poppet valve 202, and the control oil circuit also does not flow through the active safety valve 208. Therefore, in the high-pressure mold locking and piston control process, the related oil supply completely bypasses the active safety valve 208, and the active safety valve 208 does not need to participate.

[0041] The root cause is that the main function of the active safety valve 208 is to serve as a safety interlocking device for mold opening and closing action, and to ensure that the hydraulic system cannot act in a non-safe state during equipment operation. However, in the high-pressure mold locking and piston sealing stage, the system has entered the pressure maintaining state, and the valve is no longer needed for dynamic flow control or direction switching. If high-pressure oil continues to flow through the valve, not only does it bear a high-pressure load for a long time, but also it causes the electromagnetic element to be continuously powered, which easily causes problems such as overheating of the valve body, accelerated aging of the sealing element, and burning of the electromagnetic coil, and seriously affects the service life.

[0042] By decoupling the oil circuit of high-pressure mold locking and piston control from the active safety valve 208, only in the straight mold opening and closing stage, the valve controls the main oil circuit on-off, and in the remaining working conditions, the valve is in a power-off pressure maintaining state, which fundamentally reduces the working load and power-on time of the valve. This not only effectively avoids the performance degradation caused by long-term power-on and high-pressure load, but also significantly prolongs the service life of the active safety valve 208, reduces the equipment failure rate and maintenance cost.

[0043] The first one-way throttle valve 204 in the pressure relief circuit can adjust the opening degree of the throttle port to control the flow rate when the plunger cylinder 209 is relieved.

[0044] By adjusting the opening degree of the throttle port of the first one-way throttle valve 204, the relief rate of the high-pressure cavity of the plunger cylinder 209 can be accurately controlled, and the traditional instantaneous high-pressure release is changed into a controllable gradual relief process. This design effectively suppresses the severe pressure fluctuation in the relief process, significantly reduces the hydraulic impact force, effectively suppresses the abnormal vibration of the mold plate caused by pressure drop, avoids structural fatigue damage, and improves the smoothness and reliability of the equipment operation.

[0045] Further, the first cartridge valve 212 is in an open state in a normal state and has no back pressure, and the system pressure can be automatically released through the valve when the equipment is stopped.

[0046] The first plug-in valve 212 keeps the spool open in the power-off state, allowing the oil in the rod cavity of the quick cylinder 210 to directly communicate with the oil tank. This design ensures that the system residual pressure can be continuously discharged through this path during equipment shutdown, maintenance or debugging, completely eliminating the hidden danger of hydraulic circuit caused by pressure retention. When the operator disassembles the oil pipe or replaces the element, there is no longer the risk of high-pressure oil suddenly spraying, significantly improving the safety of the operation process.

[0047] The injection circuit includes three main modules: injection cylinder control module, glue melting back pressure module, and injection displacement cylinder control module.

[0048] Injection cylinder control module: This module is controlled by the fourth electromagnetic directional valve 301. When the fourth electromagnetic directional valve 301 is powered on in the left position, the injection action is performed; when it is powered on in the right position, the injection retreat action is performed.

[0049] Glue melting back pressure module: This module consists of a proportional back pressure valve 303 and a second plug-in valve 304. The pressure set by the proportional back pressure valve 303 serves as the pilot control pressure of the second plug-in valve 304, which controls the oil return pressure of the glue melting motor by adjusting the oil return resistance. This not only accurately adjusts the screw retreat speed, but also ensures uniform plasticization of the glue and stable density.

[0050] Injection displacement cylinder control module: This module is controlled by the fifth electromagnetic directional valve 302. When the fifth electromagnetic directional valve 302 is powered on in the left position, the injection seat advances; when it is powered on in the right position, the injection seat retreats.

[0051] This modular injection circuit design realizes independent and precise control of injection, glue melting and injection displacement actions. Specifically: Injection cylinder control module: The fourth electromagnetic directional valve 301 is used to switch between injection and injection retreat actions, ensuring accurate control of the injection process.

[0052] Glue melting back pressure module: The proportional back pressure valve 303 is used in conjunction with the second plug-in valve 304 to dynamically adjust the glue melting back pressure, ensuring uniform plasticization of the glue and stable density. This not only improves the dimensional accuracy and physical property consistency of the product, but also enhances the system's adaptability to different process parameters, meeting the production needs of high-precision products.

[0053] Injection displacement cylinder control module: The fifth electromagnetic directional valve 302 is used to control the advance and retreat actions of the injection seat, ensuring the stability and accuracy of the injection seat movement.

[0054] Through this modular design, the injection circuit not only ensures operational flexibility, but also significantly improves the overall performance and reliability of the system.

[0055] When the second electromagnetic reversing valve 207 is powered, the pressure oil flows through it to the first check valve 203, enters the high-pressure cavity of the plunger cylinder 209, and realizes high-pressure mold locking; when the first electromagnetic reversing valve 205 and the first poppet valve 202 lose power, the piston 201 moves to the right under the action of the spring force, and forms a linear seal with the plunger cylinder body, isolating the high-pressure cavity from the oil tank.

[0056] The control logic ensures that the high-pressure mold locking action is directly driven by the independent oil circuit composed of the second electromagnetic reversing valve 207 and the first check valve 203, and the oil does not flow through the active safety valve 208, thereby reducing the load of the valve from the source. At the same time, in the state that the first electromagnetic reversing valve 205 and the first poppet valve 202 lose power, the piston 201 is automatically reset by the spring force, forming a reliable linear seal with the plunger cylinder body, effectively blocking the path between the high-pressure cavity and the oil tank, and ensuring the stable maintenance of the mold locking pressure. This double mechanism not only significantly reduces the working time and power-on load of the active safety valve 208, effectively prolonging its service life, but also improves the stability and sealing reliability of the mold locking process.

[0057] After the second poppet valve 206 is powered on, the oil path between the high-pressure cavity of the plunger cylinder 209 and the first check throttle valve 204 is opened, allowing the high-pressure oil to slowly return to the oil tank through the throttle.

[0058] After the second poppet valve 206 is powered on, the pressure relief channel is opened, and the high-pressure oil in the high-pressure cavity of the plunger cylinder 209 must pass through the adjustable first check throttle valve 204 to return to the oil tank, forming a "pilot control + throttling regulation" double-buffering mechanism. This design further enhances the controllability of the pressure relief process, making the pressure drop more gentle, effectively suppressing the pressure impact and vibration of the hydraulic system, and improving the smoothness of the equipment in high-pressure switching conditions.

[0059] In the melt back pressure module, the pressure set by the proportional back pressure valve 303 serves as the pilot control pressure of the second cartridge valve 304, which controls the oil return pressure of the melt motor by adjusting the oil return resistance, thereby accurately adjusting the screw retreat speed and glue density.

[0060] The proportional back pressure valve 303 acts as a pilot valve, allowing stepless adjustment of the opening pressure of the second cartridge valve 304, and thus accurately controlling the oil return resistance of the melt motor. This closed-loop control mechanism realizes high-precision and dynamic adjustment of the melt back pressure, ensuring stable screw retreat speed, uniform plasticization of the glue, and consistent density. This not only improves the dimensional accuracy and consistency of physical properties of injection molded products, but also enhances the adaptability of the system to different materials and process parameters, especially for high-precision products with strict material performance requirements. It is a fine control of the melt injection process, effectively improving the overall molding quality.

[0061] The linear hydraulic cylinder 210 adopts a differential connection method when the mold is closed quickly, that is, the oil discharged from the rod chamber flows into the rodless chamber through the second one-way valve 214 to achieve a large flow rate and rapid forward movement; when the mold is closed or opened slowly, the oil in the rod chamber returns to the oil tank through the electro-hydraulic directional valve 211 and the first cartridge valve 212.

[0062] This differential connection allows the oil in the rod chamber of the direct-acting hydraulic cylinder 210 to be directly replenished into the rodless chamber through the second one-way valve 214, creating a flow-increasing effect of "driving oil intake from a small-area chamber to drive oil in a large-area chamber." This significantly improves the cylinder's extension speed during the rapid mold closing stage, effectively shortening the molding cycle. During the slow mold closing or opening stage, by controlling the energization of the third electromagnetic reversing valve 213 and adjusting the opening degree of the first cartridge valve 212, controllable back pressure can be applied to the oil return from the rod chamber, achieving speed regulation and end-effector buffering. This design optimizes the dynamic performance of the mold opening and closing process, ensuring high-speed operating efficiency while also considering the smoothness of the movement's end, thus improving the overall operating quality of the equipment.

[0063] This solution also proposes a direct-pressure press, including the aforementioned hydraulic transmission control system.

[0064] This solution addresses three key technical challenges of traditional direct-pressure presses in practical applications: large pressure relief impact, short lifespan of active safety valves, and high safety risks during maintenance and debugging. It proposes an integrated and modular hydraulic transmission control system for direct-pressure presses. Through innovative circuit design, this system achieves precise control and safety optimization of core processes such as mold locking, pressure relief, mold opening and closing, and injection molding.

[0065] In terms of technical solution, this solution establishes an independent high-pressure locking circuit consisting of a second electromagnetic directional valve 207 and a first one-way valve 203, allowing high-pressure oil to directly enter the high-pressure chamber of the plunger cylinder 209, effectively bypassing the active safety valve 208 and significantly reducing its workload and energizing time. This fundamentally solves the problem of shortened lifespan of the active safety valve 208 due to prolonged energization. Furthermore, by introducing a controllable pressure relief structure consisting of a second lifting valve 206 and a first one-way throttle valve 204 into the pressure relief circuit, flexible adjustment of the pressure relief flow rate is achieved. The instantaneous high-pressure release is transformed into a controllable, gradual pressure relief process, which significantly suppresses pressure fluctuations and hydraulic shocks, avoids abnormal vibration of the template, and improves the stability of equipment operation. By designing the first cartridge valve 212, which is controlled by the third electromagnetic reversing valve 213, and keeping its valve core open in the power-off state, a normally conductive return oil passage is formed. This ensures that the system pressure can be automatically released through the first cartridge valve 212 in the case of shutdown or power failure, completely eliminating the risk of high-pressure oil injection caused by residual pressure and greatly improving the safety of equipment maintenance and commissioning.

[0066] In addition, the system also adopts a differential connection method in the rapid mold closing stage of the straight-line cylinder 210, so that the oil in the rod chamber is replenished into the rodless chamber through the second one-way valve 214, which significantly improves the mold closing speed and shortens the molding cycle. By adjusting the opening pressure of the second cartridge valve 304 through the proportional back pressure valve 303 in the injection circuit, the system can achieve precise control of the melt back pressure, thereby regulating the screw retraction speed and the density of the rubber, and further optimizing the overall machine performance.

[0067] This solution not only effectively addresses long-standing pain points in the industry, but also features a reasonable structure and reliable control, making it highly practical and valuable for widespread adoption. It is particularly suitable for the stable and efficient production of high-precision, thick-mold, and deep-cavity injection molded products, providing a feasible solution for the upgrading and development of direct-pressure injection molding technology.

[0068] It should be noted that in this invention, the use of terms such as "first," "second," and "a" is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. The terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two elements or the interaction between two elements, unless otherwise explicitly specified. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0069] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are feasible for those skilled in the art. If the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0070] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A hydraulic transmission control system for a direct-drive press, the direct-drive press comprising a direct-drive cylinder (210) and a piston cylinder (209), characterized in that, The hydraulic transmission control system includes: A mold-locking circuit is used to control the speed of direct mold opening and closing and to lock and maintain the mold at a set pressure; the mold-locking circuit includes: an active safety valve (208), an electro-hydraulic directional valve (211), a piston control assembly, and a first cartridge valve (212). The active safety valve (208) has its B and T ports connected to the system oil supply, and its A and P ports connected to the P port of the electro-hydraulic directional valve (211). The A port of the electro-hydraulic directional valve (211) is connected to the rodless chamber of the direct-drive cylinder (210), and its B port is connected to the rod chamber of the direct-drive cylinder (210). The T port of the electro-hydraulic directional valve (211) returns to the oil tank through the first cartridge valve (212). The piston control assembly consists of the first solenoid directional valve (205), the first lifting valve (202), and the piston (201), and is used to control the connection and disconnection between the high-pressure chamber of the plunger cylinder (209) and the oil tank. The high-pressure circuit for mold locking consists of a second electromagnetic reversing valve (207) and a first check valve (203), and the oil directly enters the high-pressure chamber of the plunger cylinder (209); The pressure relief circuit consists of a second lifting valve (206) and a first one-way throttle valve (204), and the pressure relief flow rate is controlled by adjusting the size of the throttle orifice; The injection circuit controls the density of the adhesive material and performs the injection action by controlling the back pressure of the molten adhesive. The first cartridge valve (212) is controlled by the third solenoid directional valve (213) to open and close the valve core; When the third solenoid directional valve (213) is not energized, the valve core of the first cartridge valve (212) opens, and the rod chamber of the direct-drive cylinder returns oil without back pressure; When the third solenoid directional valve (213) is energized, the valve core of the first cartridge valve (212) is closed or back pressure is generated for slow mold closing or mold opening buffering.

2. The hydraulic transmission control system for a direct press as described in claim 1, characterized in that, In the mold-locking circuit, the oil supply controlled by the high-pressure mold lock and piston (201) does not pass through the active safety valve (208), so that the active safety valve (208) is energized only during direct quick mold opening and closing.

3. A hydraulic transmission control system for a direct press as described in claim 1, characterized in that, The first one-way throttle valve (204) in the pressure relief circuit can adjust the throttle opening to control the flow rate when the plunger cylinder (209) is depressurized.

4. A hydraulic transmission control system for a direct press as described in claim 1, characterized in that, The first cartridge valve (212) is normally open with zero back pressure, and the system pressure is released through the first cartridge valve (212) when the machine is stopped.

5. A hydraulic transmission control system for a direct press as described in claim 1, characterized in that, The injection circuit includes: The injection cylinder control module switches the injection / retraction action via the fourth solenoid directional valve (301); The melt back pressure module adjusts the opening pressure of the second cartridge valve (304) by the proportional back pressure valve (303); The injection cylinder control module executes the injection seat forward and backward movements through the fifth solenoid directional valve (302).

6. A hydraulic transmission control system for a direct press as described in claim 2, characterized in that: When the second electromagnetic reversing valve (207) is energized, the pressure oil flows through it to the first check valve (203) and enters the high-pressure chamber of the plunger cylinder (209) to achieve high-pressure mold locking; When the first electromagnetic reversing valve (205) and the first lifting valve (202) are not energized, the piston (201) moves to the right under the action of the spring force and forms a line seal with the plunger cylinder, isolating the high-pressure chamber from the oil tank.

7. A hydraulic transmission control system for a direct press as described in claim 3, characterized in that, After the second lifting valve (206) is energized, it opens the oil passage between the high pressure chamber of the plunger cylinder (209) and the first one-way throttle valve (204), so that the high pressure oil is slowly discharged back to the oil tank through the throttle port.

8. A hydraulic transmission control system for a direct press as described in claim 5, characterized in that, In the melt back pressure module, the proportional back pressure valve (303) sets the pressure as the pilot control pressure of the second cartridge valve (304) and adjusts the return oil resistance to control the return oil pressure of the melt motor.

9. A hydraulic transmission control system for a direct press as described in claim 1, characterized in that, The direct-drive cylinder (210) adopts a differential connection method when the mold is closed quickly, that is, the oil in the rod chamber flows into the rodless chamber through the second one-way valve (214) to achieve a large flow rate and rapid forward movement; when the mold is closed or opened slowly, the oil in the rod chamber returns to the oil tank through the electro-hydraulic directional valve (211) and the first cartridge valve (212).

10. A direct-pressure press, characterized in that, Includes a hydraulic transmission control system for a direct press as described in any one of claims 1 to 9.

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