A feed device for an injection molding machine

Abstract

The utility model discloses a kind of feeding devices of injection molding machine, including sequentially communicating hopper, conveying pipe and material cylinder, the pressure-maintaining cavity for storing material is in the material cylinder, the pusher rod is slidably connected in the pressure-maintaining cavity, the pusher rod is connected with the hydraulic cylinder for driving it to move, the oil circuit of the hydraulic cylinder is connected with the pressure relief valve for maintaining the pressure in the pressure-maintaining cavity, by setting the pressure-maintaining cavity for storing material in the material cylinder, after raw material is conveyed to the pressure-maintaining cavity by conveying pipe, when the pressure in the pressure-maintaining cavity is too large, the pressure in the pressure-maintaining cavity can be kept constant by pressure relief valve, so as to ensure that raw material can be fully foamed in the pressure-maintaining cavity with constant pressure, guarantee the uniformity of raw material foaming, so that subsequent injection into mold forming can well guarantee the quality of product, finally effectively improve foaming uniformity and injection quality.

Description

Technical Field

[0001] This utility model relates to the field of injection molding machines, and in particular to a feeding device for an injection molding machine. Background Technology

[0002] Injection molding machines are the main molding equipment used to make various shapes of plastic products from thermoplastic or thermosetting plastics using plastic molds. They are widely used in many fields such as packaging, automobiles, electronics, medical, and home furnishings.

[0003] The injection system is the core component of an injection molding machine. It is responsible for heating and melting the plastic raw material and injecting it into the mold cavity under high pressure. The injection system mainly includes a front-end feeding device and a rear-end injection head. The heated and melted plastic raw material is transported to the injection head through the feeding device and finally injected into the mold cavity. Currently, in the plastic injection molding industry, foaming agents are sometimes added to the plastic raw material. By foaming the raw material with foaming agents, the weight of plastic products can be significantly reduced, and the cost of raw materials can also be effectively reduced. However, because foaming agents are added to the plastic raw material, the raw material is directly injected into the injection head under the action of the feeding device. This can easily lead to product defects caused by uneven foaming, resulting in an increased scrap rate. Further improvements are needed. Utility Model Content

[0004] To further improve foaming uniformity and injection molding quality, this application provides a feeding device for an injection molding machine.

[0005] This application provides a feeding device for an injection molding machine, which adopts the following technical solution: A feeding device for an injection molding machine includes a hopper, a conveying pipe, and a barrel connected in sequence. The barrel has a pressure-holding chamber for storing material. A push rod is slidably connected in the pressure-holding chamber. A hydraulic cylinder is connected to the push rod to drive its movement. A pressure relief valve for maintaining the pressure in the pressure-holding chamber is connected to the oil circuit of the hydraulic cylinder.

[0006] Optionally, a linear displacement sensor is installed on the push rod.

[0007] Optionally, a conveying screw is provided inside the conveying pipe, and a drive motor for driving the conveying screw to rotate is provided at one end of the conveying pipe.

[0008] Optionally, a connecting pipe is provided between the conveying pipe and the material cylinder, and a one-way valve is provided on the connecting pipe, which ensures that the raw material can only flow from the conveying pipe to the material cylinder.

[0009] Optionally, the one-way valve includes a fixed seat and a ball. The fixed seat has a vertical through hole. The connecting pipe has a pipeline for raw materials to pass through. The ball is located between the through hole and the pipeline. The ball is used to seal the through hole or the pipeline. The connecting pipe has an installation cavity for installing the ball. The inner wall of the through hole has a perforation that communicates with the installation cavity.

[0010] Optionally, the outer diameter of the sphere is larger than the diameter of the pipe and the diameter of the through hole. When the sphere blocks the through hole, the pipe is connected to the mounting cavity.

[0011] Optionally, the push rod has a plate fixed thereto, and the linear displacement sensor is mounted on the top of the plate, located outside the material cylinder and hydraulic cylinder.

[0012] Optionally, a guide post is provided between the material cylinder and the hydraulic cylinder to connect the two. The guide post passes through the plate and the plate is slidably connected to the guide post.

[0013] Optionally, the plate is fixed to the end of the push rod located outside the material cylinder, and the piston rod of the hydraulic cylinder is fixed to the plate.

[0014] Optionally, at least two conveying pipes and material cylinders are arranged side by side, with each conveying pipe corresponding to a material cylinder.

[0015] In summary, this application includes at least one of the following beneficial technical effects: 1. By setting a pressure-holding chamber for material storage inside the barrel, the raw material is transported into the pressure-holding chamber through the conveying pipe. As the raw material continuously enters, when the pressure inside the pressure-holding chamber becomes too high, the pressure can be kept constant by the pressure relief valve. This ensures that the raw material can fully foam in the pressure-holding chamber under constant pressure, ensuring the uniformity of the foam. This ensures the quality of the product when it is subsequently injected into the mold, and ultimately effectively improves the foaming uniformity and injection molding quality.

[0016] 2. The linear displacement sensor can detect the movement distance of the push rod, and then calculate the amount of raw material in the pressure holding chamber, avoiding excessive raw material entering the pressure holding chamber, thus achieving accurate quantitative injection of raw material; 3. The one-way valve ensures that the raw material can only be transported to the pressure holding chamber through the delivery pipe. When the push rod moves forward to push the material for injection, the pressure of the raw material medium drives the ball to move upward to block the pipeline, preventing the backflow of the medium during injection, and ensuring that the raw material in the pressure holding chamber can be injected into the mold well. Attached Figure Description

[0017] Figure 1 This is an overall structural diagram of an embodiment of this application.

[0018] Figure 2This is a side view of an embodiment of this application.

[0019] Figure 3 This is a cross-sectional view of an embodiment of this application.

[0020] Figure 4 yes Figure 3 Enlarged view of point A in the middle.

[0021] Explanation of reference numerals in the attached figures: 1. Hopper; 2. Conveying pipe; 3. Material cylinder; 4. Connecting pipe; 5. Conveying screw; 6. Drive motor; 7. Pressure holding chamber; 8. Seat; 9. Injection head; 10. Material channel; 11. Push rod; 12. Pushing end; 13. Hydraulic cylinder; 14. Piston; 15. Chamber; 16. Oil circuit; 17. Pressure relief valve; 18. Mounting seat; 19. Plate; 20. Guide post; 21. Linear displacement sensor; 22. Fixed seat; 23. Ball; 24. Through hole; 25. Pipeline; 26. Mounting cavity; 27. Perforation. Detailed Implementation

[0022] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.

[0023] A feeding device for an injection molding machine, such as Figure 1 and Figure 2 As shown, it includes a hopper 1, a conveying pipe 2, and a cylinder 3. The hopper 1 is located at one end of the conveying pipe 2, and the other end of the conveying pipe 2 discharges material and is connected to the cylinder 3 through a connecting pipe 4. The raw material enters the conveying pipe 2 from the hopper 1 for conveying and is finally conveyed to the cylinder 3 through the connecting pipe 4. In this embodiment, two sets of conveying pipes 2 and cylinders 3 are arranged in parallel, and the conveying pipes 2 and cylinders 3 are arranged in a one-to-one correspondence. In this way, the feeding of two kinds of raw materials can be realized simultaneously, which is suitable for two-color injection molding machines.

[0024] like Figure 2 and Figure 3 As shown, a conveying screw 5 is installed inside the conveying pipe 2, and a drive motor 6 is installed at the end of the conveying pipe 2 to drive the conveying screw 5 to rotate. In this way, the heated and melted raw material enters the conveying pipe 2 from the hopper 1, and the drive motor 6 drives the conveying screw 5 to rotate and continuously convey the raw material forward until it is conveyed into the connecting pipe 4.

[0025] like Figure 2 and Figure 3 As shown, the connecting pipe 4 is set vertically. The top end of the connecting pipe 4 is connected to the discharge end of the conveying pipe 2, and the bottom end of the connecting pipe 4 is connected to the material cylinder 3. A one-way valve is installed in the connecting pipe 4. The one-way valve ensures that the raw material medium can only flow from the conveying pipe 2 to the material cylinder 3. The design of the one-way valve prevents the raw material in the material cylinder 3 from flowing back to the conveying pipe 2 during the injection process.

[0026] like Figure 2 and Figure 3 As shown, the material cylinder 3 is horizontally positioned below and parallel to the conveying pipe 2. The inside of the material cylinder 3 contains a hollow, pressure-holding chamber 7 for material storage. A seat 8 is fixed to the front end of the material cylinder 3. The upper end of the seat 8 is connected to the connecting pipe 4. The side of the seat 8 facing away from the material cylinder 3 is used for mounting the injection head 9. The pressure-holding chamber 7 and the injection head 9 are connected to enable material injection. A material channel 10 is provided inside the seat 8. One end of the material channel 10 is connected to the pressure-holding chamber 7, and the other end is connected to the connecting pipe 4, enabling the material to be fed into the pipe. The material is slidably connected inside the barrel 3. The end of the push rod 11 inside the barrel 3 is the push end 12. At the same time, a hydraulic cylinder 13 is connected to the push rod 11 to drive it to move horizontally to realize the push injection. In actual use, the raw material is continuously transported to the pressure holding chamber 7 for storage. Since the raw material contains foaming agent, the raw material is fully foamed in the pressure holding chamber 7. Then, the push rod 11 moves forward under the drive of the hydraulic cylinder 13 to push the raw material to the injection head 9 and finally inject it into the mold to realize injection molding.

[0027] like Figure 2 and Figure 3 As shown, the hydraulic cylinder 13 has a chamber 15 for the piston 14 to move. The hydraulic cylinder 13 has an oil passage 16 connected to the chamber 15. A pressure relief valve 17 is provided on the oil passage 16. In this embodiment, the pressure of the pressure relief valve 17 is adjustable. In actual use, the pressure of the pressure relief valve 17 can be adjusted as needed to meet the needs of more occasions. As the raw material continuously enters the pressure holding chamber 7 of the barrel 3, the internal pressure continuously increases. When the pressure is too high, the pressure relief valve 17 will open, allowing the hydraulic part in the hydraulic cylinder 13 to be discharged from the oil passage 16. At this time, the push rod 11 moves appropriately to reduce the pressure, thereby maintaining a constant pressure in the pressure holding chamber 7. Then, the raw material foams in the pressure holding chamber 7 under a certain pressure, ensuring better foaming uniformity. This ensures the quality of the product when it is subsequently injected into the mold, ultimately effectively improving the foaming uniformity and injection molding quality.

[0028] like Figure 2 and Figure 3 As shown, a mounting base 18 is fixed to the end of the material cylinder 3 away from the base 8. A plate 19 is fixed to the end of the push rod 11 that protrudes from the material cylinder 3. The end of the plate 19 facing away from the push rod 11 is used to connect and fix to the piston rod of the hydraulic cylinder 13. The hydraulic cylinder 13 is fixedly installed on the end of the mounting base 18 away from the material cylinder 3, thus realizing the connection and fixation between the hydraulic cylinder 13 and the push rod 11. The base 8 has multiple guide posts 20 that pass through the plate 19. The multiple guide posts 20 are symmetrically arranged. The plate 19 is slidably connected to the guide posts 20. The sliding connection between the guide posts 20 and the plate 19 improves the stability of the horizontal movement of the push rod 11. The end of the guide post 20 is threadedly connected to the mounting base 18 to realize a detachable connection, and at the same time, it can also realize fine adjustment in length.

[0029] like Figure 2 and Figure 3 As shown, a linear displacement sensor 21 is installed between the plate 19 and the mounting base 18 to connect the two. One end of the linear displacement sensor 21 is fixed to the mounting base 18, and the other end is fixed to the plate 19. In this way, the amount of raw material entering the pressure holding chamber 7 can be calculated by measuring the moving distance of the plate 19, which can effectively realize the quantitative injection of raw materials. In this embodiment, the linear displacement sensor 21 is located outside the material cylinder 3 and the hydraulic cylinder 13, which facilitates installation and disassembly, as well as inspection and maintenance.

[0030] like Figure 3 and Figure 4 As shown, the one-way valve includes a fixed seat 22 and a ball 23. The fixed seat 22 has a vertical through hole 24, and the connecting pipe 4 has a vertical pipe 25. At the bottom end of the connecting pipe, there is a mounting cavity 26 for mounting the ball 23. The ball 23 is located below the pipe 25 and above the fixed seat 22. The ball 23 is used to close the through hole 24 or the pipe 25. The mounting cavity 26 has space for the ball 23 to move up and down, and the outer diameter of the ball 23 is larger than the diameter of the pipe 25 and the through hole 24. Additionally, a through hole 27 communicating with the mounting cavity 26 is formed on the inner wall of the through hole 24. The through hole 27 is evenly spaced around the circumference. Multiple sections are evenly spaced, so that in actual use, the raw material is transported from the conveying pipe 2 to the connecting pipe 4 and then flows from the pipe 25 to the mounting cavity 26. At this time, the ball 23 is in the state of blocking the through hole 24. The raw material in the mounting cavity 26 flows through each perforation 27 to the through hole 24 and finally enters the pressure holding cavity 7 of the material cylinder 3 to complete the feeding. When the raw material in the material cylinder 3 is injected, the hydraulic cylinder 13 drives the piston rod to move forward and push the raw material in the pressure holding cavity 7. At this time, the pressure increases and drives the ball 23 to move upward to block the pipe 25, realizing unidirectional flow and effectively preventing the raw material from flowing back to the conveying pipe 2, ensuring the effective operation of the injection process.

[0031] Working principle: The raw material enters the conveying pipe 2 from the hopper 1, and is conveyed to the connecting pipe 4 under the action of the conveying screw 5, and finally enters the pressure holding chamber 7 of the cylinder 3. As the raw material continues to enter, the pressure in the pressure holding chamber 7 continues to increase. When the internal pressure is greater than the set value of the pressure relief valve 17, the pressure relief valve 17 releases pressure, and the raw material pushes the push rod 11 to move backward. During this period, the pressure in the pressure holding chamber 7 is kept constant. During the backward movement of the push rod 11, the current feed amount in the cylinder 3 can be calculated by the linear displacement sensor 21. When the injection volume is reached in the cylinder 3, the conveying pipe 2 stops feeding. During this period, the raw material is fully and evenly foamed in the pressure holding chamber 7. Finally, the hydraulic cylinder 13 drives the push rod 11 to move forward and push the raw material for injection.

[0032] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A feeding device for an injection molding machine, characterized in that: The device includes a hopper (1), a conveying pipe (2), and a material cylinder (3) connected in sequence. The material cylinder (3) has a pressure-holding chamber (7) for storing material. A push rod (11) is slidably connected in the pressure-holding chamber (7). A hydraulic cylinder (13) is connected to the push rod (11) to drive it to move. A pressure relief valve (17) for maintaining the pressure in the pressure-holding chamber (7) is connected to the oil circuit (16) of the hydraulic cylinder (13).

2. The feeding device for an injection molding machine according to claim 1, characterized in that: A linear displacement sensor (21) is installed on the push rod (11).

3. The feeding device for an injection molding machine according to claim 1, characterized in that: The conveying pipe (2) is provided with a conveying screw (5), and a drive motor (6) is provided at one end of the conveying pipe (2) to drive the conveying screw (5) to rotate.

4. A feeding device for an injection molding machine according to any one of claims 1-3, characterized in that: A connecting pipe (4) is provided between the conveying pipe (2) and the material cylinder (3), and a one-way valve is provided on the connecting pipe (4), which allows the raw material to flow only from the conveying pipe (2) to the material cylinder (3).

5. The feeding device for an injection molding machine according to claim 4, characterized in that: The one-way valve includes a fixed seat (22) and a ball (23). The fixed seat (22) has a vertical through hole (24). The connecting pipe (4) has a pipeline (25) for raw materials to pass through. The ball (23) is located between the through hole (24) and the pipeline (25). The ball (23) is used to close the through hole (24) or the pipeline (25). The connecting pipe (4) has an installation cavity (26) for the ball (23) to be installed. The inner wall of the through hole (24) has a perforation (27) that communicates with the installation cavity (26).

6. The feeding device for an injection molding machine according to claim 5, characterized in that: The outer diameter of the sphere (23) is larger than the diameter of the pipe (25) and the diameter of the through hole (24). When the sphere (23) blocks the through hole (24), the pipe (25) is connected to the mounting cavity (26).

7. The feeding device for an injection molding machine according to claim 2, characterized in that: The push rod (11) has a plate (19) fixed thereto, and the linear displacement sensor (21) is installed on the top of the plate (19). The linear displacement sensor (21) is located outside the material cylinder (3) and the hydraulic cylinder (13).

8. The feeding device for an injection molding machine according to claim 7, characterized in that: A guide post (20) is provided between the material cylinder (3) and the hydraulic cylinder (13) to connect the two. The guide post (20) passes through the plate (19) and the plate (19) is slidably connected to the guide post (20).

9. A feeding device for an injection molding machine according to claim 7 or 8, characterized in that: The plate (19) is fixed to one end of the push rod (11) located outside the material cylinder (3), and the piston rod of the hydraulic cylinder (13) is fixed on the plate (19).

10. The feeding device for an injection molding machine according to claim 1, characterized in that: At least two conveying pipes (2) and material cylinders (3) are arranged side by side, and the conveying pipes (2) and material cylinders (3) are arranged in a one-to-one correspondence.

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