Injection molding machine oil cylinder ejection mechanism and control method thereof
By using a parallel structure of small and large hydraulic cylinders and control with an electromagnetic reversing valve, the ejection mechanism of the injection molding machine combines large ejection force with rapid ejection, solving the problem of ejection force and speed in traditional injection molding machines under space constraints, and providing an efficient and low-cost demolding solution.
Patent Information
- Application Number
- CN202511895225.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-02-27
AI Technical Summary
Traditional injection molding machine ejection mechanisms struggle to combine high ejection force with rapid ejection within limited space, resulting in high costs, complex structures, and limited installation space.
It adopts a parallel structure of small and large hydraulic cylinder components, which are independently controlled by electromagnetic reversing valves. In the initial stage of demolding, the large hydraulic cylinder component provides a large ejection force, and in the later stage, the small hydraulic cylinder component ejects quickly, realizing synchronization and rapid switching. Combined with the use of a return spring, energy consumption is reduced.
It achieves a combination of high ejection force and high ejection speed within a limited space, with a compact structure, low cost, stable operation, energy efficiency, and ensures reliable separation of products.
Smart Images
Figure CN121572540A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of injection molding equipment, specifically to an injection molding machine hydraulic cylinder ejection mechanism and its control method. Background Technology
[0002] In the injection molding process, the ejection mechanism needs to have sufficient ejection force to overcome the suction force of the mold cavity and to achieve rapid ejection to improve production efficiency. Traditional ejection mechanisms usually use a single hydraulic cylinder. To achieve a large ejection force, the cylinder diameter needs to be increased, the hydraulic pump motor needs to be enlarged to increase the pump power and pipeline size, resulting in high cost, complex structure, large size, and limited installation space.
[0003] Therefore, how to combine large ejection force with rapid ejection within a limited space has become a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0004] To address the above-mentioned technical problems, this invention provides an injection molding machine hydraulic cylinder ejection mechanism and its control method, which has a simple structure, small space occupation, and low cost; it can achieve large ejection force in the early stage of demolding and rapid ejection action in the later stage.
[0005] To achieve the above objectives, the technical solution of the present invention is as follows:
[0006] An injection molding machine hydraulic cylinder ejection mechanism includes:
[0007] The power unit and the two are connected by signals;
[0008] Small and large hydraulic cylinder assemblies are located on the rear side of the machine plate. The small hydraulic cylinder assembly has at least one small hydraulic cylinder, and the large hydraulic cylinder assembly has at least one large hydraulic cylinder. The small hydraulic cylinder assembly is a bidirectional hydraulic cylinder, and its piston rod is fixedly connected to the ejector plate. The large hydraulic cylinder assembly is a unidirectional hydraulic cylinder, and its piston rod front end contacts the ejector plate but is not fixed, and its rod cavity is provided with a return spring.
[0009] The first electromagnetic reversing valve controls the oil inlet and outlet of the small oil cylinder assembly;
[0010] The second electromagnetic reversing valve controls the oil inlet and outlet of the large hydraulic cylinder assembly;
[0011] The control system controls the power unit to connect to the small hydraulic cylinder assembly through the first electromagnetic reversing valve pipeline, and the power unit to connect to the large hydraulic cylinder assembly through the second electromagnetic reversing valve pipeline.
[0012] In the initial stage of demolding, the hydraulic cylinder ejection mechanism of this injection molding machine works synchronously with the large and small hydraulic cylinder assemblies under hydraulic drive. The total output force is the sum of the thrust of multiple large and small hydraulic cylinders, which can provide an ejection force far exceeding that of a single hydraulic cylinder, ensuring reliable separation of the product.
[0013] After the product separates from the mold cavity, the piston rod of the large hydraulic cylinder assembly automatically resets under the action of the return spring and returns to the starting position; then the small hydraulic cylinder assembly with a longer stroke and smaller cylinder diameter continues to eject. Due to the small load and the hydraulic flow concentrated in the small hydraulic cylinder, high-speed ejection motion can be achieved.
[0014] The ejection mechanism is independently controlled by a combination of large and small hydraulic cylinders in parallel and corresponding electromagnetic reversing valves. This makes the switching control logic between the two working modes of high force synchronous and fast single action clear, easy to implement, and without mutual interference. In a simple and low-cost manner, it achieves the high ejection force and high ejection speed required in the injection molding demolding process within a limited space, that is, high ejection force in the early stage of demolding and fast ejection of the product in the later stage.
[0015] In a further optimized design, the diameter of the small hydraulic cylinder assembly is smaller than that of the large hydraulic cylinder assembly, while its stroke is greater. A larger cylinder diameter provides higher ejection force, while a smaller cylinder diameter provides higher ejection speed. The larger piston rod stroke of the small hydraulic cylinder assembly facilitates faster ejection of the product later, improving production efficiency.
[0016] Further optimization of the design involves using a three-position four-way solenoid directional valve for the first valve and a two-position four-way solenoid directional valve for the second valve. Both the three-position four-way and two-position four-way solenoid directional valves are conventionally used hydraulic components, making them convenient to operate.
[0017] In a further optimized design, the front part of the ejector plate is connected to an ejector pin, which contacts the product inside the mold. By contacting the product with the ejector pin, the product is pushed to separate from the mold cavity, enabling precise force application and high ejection force even with a small area of force application.
[0018] In a further optimized scheme, the rodless chamber of the large hydraulic cylinder assembly is connected to the oil return port of the power unit through the second electromagnetic reversing valve. When the second electromagnetic reversing valve is energized, the rodless chamber of the large hydraulic cylinder assembly is connected to the oil inlet of the power unit. When the second electromagnetic reversing valve is de-energized, the piston rod of the large hydraulic cylinder assembly is reset by the return spring.
[0019] The piston rod of the large hydraulic cylinder assembly returns to its initial position via a return spring. The reset process does not consume hydraulic energy; it relies solely on the elastic potential energy stored in the return spring, effectively reducing system energy consumption and hydraulic heating.
[0020] In a further optimized scheme, the first and second electromagnetic directional valves are energized simultaneously, and high-pressure hydraulic oil enters the rodless chambers of the small and large cylinder assemblies respectively. The piston rods of the small and large cylinder assemblies jointly push the ejector plate to separate the product from the mold cavity.
[0021] The piston rods of the small and large hydraulic cylinder assemblies work together on the ejector plate to provide the high ejection force required in the initial demolding stage, ensuring that the product can be easily and smoothly separated from the mold cavity.
[0022] In a further optimized scheme, the first electromagnetic reversing valve is energized, the rodless chamber of the small cylinder assembly is connected to the oil return port of the power unit, and high-pressure hydraulic oil enters the rod chamber of the small cylinder assembly, pushing the piston rod of the small cylinder assembly to drive the ejector pin plate to reset. After reset, the ejector pin plate contacts the front end of the piston rod of the large cylinder assembly.
[0023] Further optimization involves assemblies of small and large hydraulic cylinders, with the small and large cylinders arranged symmetrically on the rear side of the machine plate. This symmetrical arrangement ensures even distribution of ejection force across the ejector plate, preventing uneven loading, jamming, or mold damage caused by single-point force application, thus guaranteeing a smooth ejection process and high-quality products.
[0024] A control method for an injection molding machine hydraulic cylinder ejection mechanism, using any of the above-described injection molding machine hydraulic cylinder ejection mechanisms, includes the following steps:
[0025] Step 1: The first electromagnetic reversing valve and the second electromagnetic reversing valve are energized simultaneously, and the piston rods of the small cylinder assembly and the large cylinder assembly simultaneously push the ejector plate, causing the product to separate from the mold cavity.
[0026] Step 2: The second electromagnetic reversing valve is de-energized, the large hydraulic cylinder assembly is reset under the action of the reset spring, and the small hydraulic cylinder assembly continues to push out until the product is completely demolded;
[0027] Step 3: The first electromagnetic reversing valve is energized, the piston rod of the small hydraulic cylinder assembly retracts, and the ejector plate resets to contact the front end of the piston rod of the large hydraulic cylinder assembly.
[0028] In a further optimized design, during the piston rod reset process of the large hydraulic cylinder assembly, its rodless chamber is connected to the oil return port of the power unit via a second electromagnetic directional valve.
[0029] In a further optimized design, the piston rod of the small hydraulic cylinder assembly is always controlled by the first electromagnetic directional valve to allow oil to enter its rodless chamber during the ejection process.
[0030] Compared with the prior art, the injection molding machine hydraulic cylinder ejection mechanism and its control method of the present invention have the following technical advantages:
[0031] 1. Achieving a combination of high ejection force and rapid ejection action: By activating the large and small hydraulic cylinders simultaneously, a super-large ejection force is provided to ensure product demolding; then the large hydraulic cylinder automatically retracts under the action of the spring, and only the small hydraulic cylinder completes the rapid ejection, perfectly solving the contradiction between high ejection force and high speed that traditional mechanisms cannot achieve simultaneously.
[0032] 2. Faster response and energy-efficient: The large hydraulic cylinder adopts a built-in spring reset, and its reset process is a purely mechanical action. Compared with hydraulic reset, it is faster and more reliable. At the same time, it saves the hydraulic energy and corresponding control required for the return stroke, reducing system energy consumption and heat generation.
[0033] 3. Compact structure and balanced force distribution: Multiple small hydraulic cylinders are connected in parallel with large hydraulic cylinders and arranged symmetrically to replace a single giant hydraulic cylinder, making the structure more compact and adaptable to limited installation space; at the same time, the top force is evenly distributed, the operation is stable, and the problem of uneven load is avoided.
[0034] 4. Simple and reliable control: Two electromagnetic reversing valves are used to independently control the large and small hydraulic cylinder components. The oil circuit and control logic are clear and simple, realizing reliable and precise switching between two working modes: high-pressure synchronous and fast single-action. The system has good stability. Attached Figure Description
[0035] Figure 1 This is a schematic diagram of a specific embodiment of the injection molding machine cylinder ejection mechanism of the present invention;
[0036] Figure 2 yes Figure 1 AA section view;
[0037] Figure 3 yes Figure 2 A diagram illustrating the ejection action;
[0038] Figure 4 yes Figure 3 Schematic diagram of the large hydraulic cylinder's reset spring;
[0039] Figure 5 yes Figure 4 A schematic diagram illustrating how the small hydraulic cylinder assembly ejects the product.
[0040] Figure 6 yes Figure 5 Schematic diagram of the small hydraulic cylinder assembly driving the ejector pin to reset.
[0041] In the diagram: Power unit 1, first oil inlet pipe 2, second oil return pipe 3, first solenoid directional valve 4, third oil pipe 5, fourth oil pipe 6, machine plate 7, first connecting pipe 8, small oil cylinder assembly 9, large oil cylinder assembly 10, second connecting pipe 11, third connecting pipe 12, fifth oil pipe 13, second solenoid directional valve 14, sixth oil inlet pipe 15, seventh oil return pipe 16, first small oil cylinder inlet 17, small oil cylinder piston rod 18, second small oil cylinder inlet 19, ejector plate 20, ejector rod 21, mold 22, product 23, large oil cylinder inlet 24, return spring 25, large oil cylinder piston rod 26, hydraulic oil 27. Detailed Implementation
[0042] The present invention will now be described in further detail with reference to the embodiments shown in the accompanying drawings.
[0043] like Figures 1 to 6 As shown, this invention provides a specific embodiment of the injection molding machine cylinder ejection mechanism.
[0044] like Figure 1 and Figure 2 As shown, the injection molding machine cylinder ejection mechanism of this embodiment includes:
[0045] Power unit 1, the two are connected by signals;
[0046] Small cylinder assembly 9 and large cylinder assembly 10 are located on the rear side of machine plate 7. Small cylinder assembly 9 is provided with at least one small cylinder, and large cylinder assembly 10 is provided with at least one large cylinder. Small cylinder assembly 9 is a bidirectional cylinder, and its piston rod is fixedly connected to ejector plate 20. Large cylinder assembly 10 is a unidirectional cylinder, and the front end of its piston rod contacts ejector plate 20 but is not fixed. A return spring 25 is provided in its rod cavity.
[0047] The first electromagnetic reversing valve 4 controls the inlet and outlet of oil in the small oil cylinder assembly 9;
[0048] The second electromagnetic reversing valve 14 controls the inlet and outlet of oil in the large oil cylinder assembly 10;
[0049] The control system (not shown in the figure) controls the power unit 1, which is connected to the small cylinder assembly 9 through the first electromagnetic reversing valve 4, and the power unit 1 is connected to the large cylinder assembly 10 through the second electromagnetic reversing valve 14.
[0050] Preferably, the small hydraulic cylinder assembly 9 includes two small hydraulic cylinders connected in parallel by hydraulic circuits, and the large hydraulic cylinder assembly 10 includes two large hydraulic cylinders connected in parallel by hydraulic circuits. The small and large hydraulic cylinders are evenly and symmetrically arranged on the rear side of the machine plate 7. The even and symmetrical arrangement of the small and large hydraulic cylinders ensures that the ejection force is evenly distributed on the ejector plate 20, avoiding uneven loading, jamming, or damage to the mold 22 caused by single-point force, thus ensuring the stability of the ejection process and the quality of the product 23.
[0051] The number and layout of small and large oil cylinders can be set according to the actual situation and are not limited by the above. Alternatively, a large oil cylinder can be placed in the middle and a small oil cylinder can be arranged symmetrically on both sides; or a large oil cylinder can be placed in the middle and three small oil cylinders can be evenly distributed around it.
[0052] In the initial stage of demolding, the injection molding machine's hydraulic cylinder ejection mechanism works synchronously under hydraulic drive through the large hydraulic cylinder assembly 10 and the small hydraulic cylinder assembly 9. The total output force is the sum of the thrust of multiple large and small hydraulic cylinders, which can provide an ejection force far exceeding that of a single hydraulic cylinder, ensuring reliable separation of the product 23.
[0053] After the product 23 separates from the mold cavity of the mold 22, the piston rod of the large hydraulic cylinder assembly 10 automatically resets under the action of the return spring 25 and returns to the starting position; then the small hydraulic cylinder assembly 9 with a longer stroke and smaller cylinder diameter continues to eject. Due to the small load and the hydraulic flow concentrated in the small hydraulic cylinder, high-speed ejection motion can be achieved.
[0054] The ejection mechanism is independently controlled by a combination of large and small hydraulic cylinders in parallel and corresponding electromagnetic reversing valves. This makes the switching control logic between the two working modes of high force synchronous and fast single action clear, easy to implement, and without mutual interference. In a simple and low-cost manner, it achieves the high ejection force and high ejection speed required in the injection molding demolding process in a limited space, namely, high ejection force in the early stage of demolding and rapid ejection of the product in the later stage.
[0055] like Figure 1 and Figure 2 As shown, the cylinder diameter of the small cylinder assembly 9 is smaller than that of the large cylinder assembly 10, but its stroke is greater than that of the large cylinder assembly 10. A larger cylinder diameter can provide higher ejection force, while a smaller cylinder diameter can provide higher ejection speed. The piston rod stroke of the small cylinder assembly 9 being greater than that of the large cylinder assembly 10 is beneficial for quickly ejecting the product 23 in the later stages, thereby improving production efficiency.
[0056] like Figure 1 As shown, the first solenoid directional valve 4 is a three-position four-way solenoid directional valve, and the second solenoid directional valve 14 is a two-position four-way solenoid directional valve. Both the three-position four-way and two-position four-way solenoid directional valves are conventionally used hydraulic components and are easy to operate.
[0057] like Figure 2 As shown, the front of the ejector plate 20 is connected to the ejector rod 21, which contacts the product 23 inside the mold 22. By contacting the product 23 with the ejector rod 21, the product 23 is pushed to separate from the mold cavity of the mold 22, which can achieve high ejection force by applying force at a precise position and with a small area of force.
[0058] like Figure 2As shown, each cylinder in the small cylinder assembly 9 is provided with a first small cylinder inlet 17, a small cylinder piston rod 18, and a second small cylinder inlet 19; each cylinder in the large cylinder assembly 10 is provided with a large cylinder inlet 24 and a large cylinder piston rod 26. Figure 1 As shown, the first connecting pipe 8 connects to the oil inlets 17 of the two first small oil cylinders, the second connecting pipe 11 connects to the oil inlets 19 of the two second small oil cylinders, and the third connecting pipe 12 connects to the oil inlets 24 of the two large oil cylinders.
[0059] like Figure 1 As shown, the oil inlet P and oil return T of the first solenoid directional valve 4 are connected to the oil inlet P and oil return T of the power unit 1 through the first oil inlet pipe 2 and the second oil return pipe 3, respectively. The A port of the first solenoid directional valve 4 is connected to the oil inlet of the small oil cylinder, and the B port of the first solenoid directional valve 4 is connected to the oil inlet of the small oil cylinder. The oil inlet P and oil return T of the second solenoid directional valve 14 are connected to the oil inlet P and oil return T of the power unit 1 through the sixth oil inlet pipe 15 and the seventh oil return pipe 16, respectively. When not in the neutral position, the A port and T port of the second solenoid directional valve 14 are connected to the oil inlet 24 of the large oil cylinder.
[0060] like Figure 2 As shown, the rodless chamber of the large hydraulic cylinder assembly 10 is connected to the oil return port of the power unit 1 through the second electromagnetic reversing valve 14. When the second electromagnetic reversing valve 14 is energized, the rodless chamber of the large hydraulic cylinder assembly 10 is connected to the oil inlet port of the power unit 1. When the second electromagnetic reversing valve 14 is de-energized, the piston rod of the large hydraulic cylinder assembly 10 is reset by the return spring 25.
[0061] The piston rod of the large hydraulic cylinder assembly 10 returns to the starting position via the return spring 25. The reset process does not consume hydraulic energy, but relies solely on the elastic potential energy stored in the return spring 25, which effectively reduces system energy consumption and oil heating.
[0062] like Figure 3 As shown, the first electromagnetic reversing valve 4 and the second electromagnetic reversing valve 14 are energized simultaneously, and the high-pressure hydraulic oil 27 enters the rodless chamber of the small cylinder assembly 9 and the large cylinder assembly 10 respectively. The piston rods of the small cylinder assembly 9 and the large cylinder assembly 10 jointly push the ejector plate 20 to separate the product 23 from the mold cavity of the mold 22.
[0063] The piston rods of the small hydraulic cylinder assembly 9 and the large hydraulic cylinder assembly 10 work together on the ejector plate 20, which can provide the high ejection force required in the early stage of demolding, ensuring that the product 23 can be easily and smoothly separated from the mold cavity of the mold 22.
[0064] like Figure 6As shown, the first electromagnetic reversing valve 4 is energized and reversed, connecting the rodless chamber of the small cylinder assembly 9 with the return port of the power unit 1. High-pressure hydraulic oil 27 enters the rod chamber of the small cylinder assembly 9, pushing the piston rod of the small cylinder assembly 9 to drive the ejector pin 20 to reset. After reset, the ejector pin 20 contacts the front end of the piston rod of the large cylinder assembly 10.
[0065] like Figures 2 to 6 As shown, a control method for the ejection mechanism of an injection molding machine cylinder, using the aforementioned ejection mechanism, includes the following steps:
[0066] Step 1: Part a of the first electromagnetic reversing valve 4 and the second electromagnetic reversing valve 14 are energized simultaneously. At this time, the high-pressure hydraulic oil 27 enters the rodless chamber of the small cylinder assembly 9 and the rodless chamber of the large cylinder assembly 10 through the third oil pipe 5 and the fifth oil pipe 13 respectively, pushing the small cylinder piston rod 18 and the large cylinder piston rod 26 to drive the ejector plate 20 and the ejector rod 21 to separate the product 23 from the mold cavity surface of the mold 22. At this time, the return spring 25 is compressed a certain distance and reaches the cylinder stroke of the large cylinder assembly 10.
[0067] Step two: The second electromagnetic reversing valve 14 is de-energized, and the hydraulic oil 2727 in the large hydraulic cylinder assembly 10 is connected to the T port of the power unit 1 through the second electromagnetic reversing valve 14. Under the elastic deformation of the return spring 25, the large hydraulic cylinder piston rod 2626 returns to its original position, and the front end face of the large hydraulic cylinder piston rod 26 disengages from the ejector plate 20. At the same time, the first electromagnetic reversing valve 4 continues to be energized at part a, pushing the small hydraulic cylinder piston rod 18 and the ejector rod 21 to continue to advance until the product 23 is ejected from the mold 22.
[0068] Step 3: The second electromagnetic directional valve 14 continues to be de-energized, and part b of the second electromagnetic directional valve 14 is energized. The rodless chamber of the small cylinder assembly 9 is connected to the return oil T port of the power unit 1. The high-pressure hydraulic oil 27 enters the rod chamber of the small cylinder assembly 9 through the fourth oil pipe 6 and the oil inlet 19 of the second small cylinder, pushing the small cylinder piston rod 18 to drive the ejector plate 20 and ejector rod 21 to move backward until the ejector piston rod returns to the starting position. At this time, the rear plane of the ejector plate 20 just touches the front end face of the large cylinder piston rod 26, and the action is completed.
[0069] During the piston rod reset process of the large hydraulic cylinder assembly 10, its rodless chamber is connected to the oil return port of the power unit 1 through the second solenoid directional valve 14. During the ejection process, the piston rod of the small hydraulic cylinder assembly 9 is always controlled by the first solenoid directional valve 4 to allow oil to enter its rodless chamber.
[0070] The injection molding machine hydraulic cylinder ejection mechanism and its control method of the present invention have a simple structure, small space occupation and low cost; they can achieve large ejection force in the early stage of demolding and rapid ejection action in the later stage.
[0071] In summary, as described in the specification and figures, this invention has been manufactured into actual samples and tested multiple times. The test results demonstrate that the invention achieves its intended purpose, and its practicality is beyond doubt. The embodiments described above are merely for illustrative purposes and are not intended to limit the scope of the invention. Any equivalent embodiments made by those with common knowledge in the relevant technical field, utilizing the technical content disclosed in this invention without departing from the scope of the technical features and similar features of this invention, based on partial modifications or alterations, are within the protection scope of this invention.
Claims
1. A hydraulic cylinder ejection mechanism for an injection molding machine, characterized in that, include: The power unit (1) and the control system are connected by signals; Small cylinder assembly (9) and large cylinder assembly (10) are arranged on the rear side of the machine plate (7). The small cylinder assembly (9) is provided with at least one small cylinder, and the large cylinder assembly (10) is provided with at least one large cylinder. The small cylinder assembly (9) is a bidirectional cylinder, and its piston rod is fixedly connected to the ejector plate (20). The large cylinder assembly (10) is a unidirectional cylinder, and its piston rod front end contacts the ejector plate (20) but is not fixed. A return spring (25) is provided in its rod cavity. The first electromagnetic reversing valve (4) controls the oil inlet and outlet of the small oil cylinder assembly (9); The second electromagnetic reversing valve (14) controls the inlet and outlet of oil in the large oil cylinder assembly (10); The control system controls the power unit (1) to connect to the small cylinder assembly (9) through the first electromagnetic reversing valve (4) pipeline, and the power unit (1) is connected to the large cylinder assembly (10) through the second electromagnetic reversing valve (14) pipeline.
2. The injection molding machine cylinder ejection mechanism according to claim 1, characterized in that, The cylinder diameter of the small cylinder assembly (9) is smaller than that of the large cylinder assembly (10), and its stroke is greater than that of the large cylinder assembly (10).
3. The injection molding machine cylinder ejection mechanism according to claim 1, characterized in that, The first solenoid directional valve (4) is a three-position four-way solenoid directional valve, and the second solenoid directional valve (14) is a two-position four-way solenoid directional valve.
4. The injection molding machine cylinder ejection mechanism according to claim 1, characterized in that, The front part of the ejector plate (20) is connected to the ejector rod (21), and the ejector rod (21) contacts the product (23) inside the mold (22).
5. The injection molding machine cylinder ejection mechanism according to claim 1, characterized in that, The rodless chamber of the large hydraulic cylinder assembly (10) is connected to the oil return port of the power unit (1) through the second electromagnetic reversing valve (14). When the second electromagnetic reversing valve (14) is energized, the rodless chamber of the large hydraulic cylinder assembly (10) is connected to the oil inlet port of the power unit (1). When the second electromagnetic reversing valve (14) is de-energized, the piston rod of the large hydraulic cylinder assembly (10) is reset by the return spring (25).
6. The injection molding machine cylinder ejection mechanism according to claim 1, characterized in that, When the first electromagnetic reversing valve (4) and the second electromagnetic reversing valve (14) are energized at the same time, high-pressure hydraulic oil enters the rodless chamber of the small cylinder assembly (9) and the large cylinder assembly (10) respectively. The piston rods of the small cylinder assembly (9) and the large cylinder assembly (10) jointly push the ejector plate (20) to separate the product (23) from the mold cavity of the mold (22).
7. The injection molding machine cylinder ejection mechanism according to claim 6, characterized in that, When the first electromagnetic reversing valve (4) is switched and energized, the rodless chamber of the small cylinder assembly (9) and the return port of the power unit (1) are connected. High-pressure hydraulic oil enters the rod chamber of the small cylinder assembly (9), pushing the piston rod of the small cylinder assembly (9) to drive the ejector plate (20) to reset. After reset, the ejector plate (20) contacts the front end of the piston rod of the large cylinder assembly (10).
8. The injection molding machine cylinder ejection mechanism according to claim 1, characterized in that, The small cylinder assembly (9) includes two small cylinders, and the large cylinder assembly (10) includes two large cylinders. The small cylinders and large cylinders are evenly and symmetrically arranged on the rear side of the machine plate (7).
9. A control method for the hydraulic cylinder ejection mechanism of an injection molding machine, characterized in that, The injection molding machine cylinder ejection mechanism according to any one of claims 1 to 8 includes the following steps: Step 1: The first electromagnetic reversing valve (4) and the second electromagnetic reversing valve (14) are energized at the same time, and the piston rods of the small oil cylinder assembly (9) and the large oil cylinder assembly (10) push the ejector plate (20) at the same time, so that the product (23) is separated from the mold cavity of the mold (22); Step 2: The second electromagnetic reversing valve (14) is de-energized, the large hydraulic cylinder assembly (10) is reset under the action of the reset spring (25), and the small hydraulic cylinder assembly (9) continues to push out until the product (23) is completely demolded; Step 3: The first electromagnetic reversing valve (4) is switched and energized, the piston rod of the small oil cylinder assembly (9) retracts, and the ejector pin (20) is reset to contact the front end of the piston rod of the large oil cylinder assembly (10).
10. The control method for the hydraulic cylinder ejection mechanism of an injection molding machine according to claim 9, characterized in that, During the piston rod reset process of the large hydraulic cylinder assembly (10), its rodless chamber is connected to the oil return port of the power unit (1) through the second electromagnetic reversing valve (14).
11. The control method for the hydraulic cylinder ejection mechanism of an injection molding machine according to claim 9, characterized in that, During the ejection process, the piston rod of the small oil cylinder assembly (9) is always controlled by the first electromagnetic reversing valve (4) to allow oil to enter its rodless chamber.