Backflow prevention structure and hot runner system

Abstract

The invention belongs to the technical field of hot runners, and discloses an anti-backflow structure and a hot runner system. The backflow prevention structure comprises a first main body, a first runner and a second runner are arranged in the first main body, and a first colloid and a second colloid can be respectively injected into the first runner and the second runner; the first runner extends from the top end of the first main body to the bottom end of the first main body in the axial direction of the first main body; the second runner spirally extends to the bottom end of the first main body from the top end of the first main body, a second glue inlet hole is formed in the top end of the first main body, a second glue outlet hole is formed in the bottom end of the first main body, and the aperture of the second glue outlet hole is smaller than that of the second glue inlet hole. The structure can be used for completing injection molding of two colloids and effectively preventing the colloids from flowing back at the same time. By applying the structure, the hot runner system can improve the yield of products.

Description

Technical Field

[0001] The present invention relates to the technical field of hot runners, and in particular to a backflow prevention structure and a hot runner system. Background Art

[0002] Hot runner systems are divided into needle valve type and open type. The needle valve type uses a driver to drive the valve needle to move, which is used to open and close the glue port to complete the injection molding. When the existing hot runner is used to inject two-color colloids, it is necessary to withdraw the valve needle after the first color colloid injection is completed, and then inject the second color colloid. However, a certain suction force will be generated during the withdrawal of the valve needle. This suction force will cause the plastic in the cavity to flow back, resulting in weld marks on the surface of the product, affecting the product appearance. At the same time, there is a strong residual internal stress in the plastic part, which affects the strength of the product.

[0003] Therefore, there is an urgent need for an anti-backflow structure and a hot runner system to prevent plastic backflow caused by valve needle retreat during two-color injection molding, thereby avoiding affecting product appearance and product strength and improving the yield rate of injection molded products. Summary of the invention

[0004] One object of the present invention is to provide an anti-backflow structure for preventing the valve needle from retreating during the injection molding of two colloids, thereby avoiding affecting the appearance and strength of the product.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] A backflow prevention structure, comprising:

[0007] The first body has a first flow channel and a second flow channel arranged therein, and the first flow channel and the second flow channel can respectively inject a first colloid and a second colloid; the first flow channel extends from the top end of the first body to the bottom end thereof along the axial direction of the first body; the second flow channel spirally extends from the top end of the first body to the bottom end thereof, and forms a second glue inlet hole at the top end of the first body, and forms a second glue outlet hole at the bottom end of the first body, and the aperture of the second glue outlet hole is smaller than the aperture of the second glue inlet hole.

[0008] Preferably, a drainage slope is provided inside the second flow channel, and the angle between the drainage slope and the top surface of the first body is 25°-30°.

[0009] Preferably, a plurality of second flow channels are evenly spaced apart along the circumference of the first body.

[0010] Preferably, the first flow channel is arranged at the center of the first body, the plurality of second flow channels are arranged at the periphery of the first flow channel, and the first flow channel is not connected to the plurality of second flow channels.

[0011] Preferably, the first flow channel forms a first glue inlet hole at the top end of the first body, and a positioning groove is arranged between the first glue inlet hole and the plurality of second flow channels.

[0012] Preferably, the anti-backflow structure also includes a second body, which is located at one end of the first body where a second glue outlet hole is provided, and the second body is provided with a third flow channel along its axial direction, and the third flow channel is connected to the first flow channel, and the first colloid can flow to the third flow channel, and the diameter of the second body is smaller than the diameter of the first body, and the second colloid can flow to the periphery of the second body.

[0013] Preferably, the first body and the second body are coaxially arranged.

[0014] Preferably, the diameter of the second body gradually decreases in a direction away from the first body.

[0015] Preferably, the first body and the second body are integrally formed.

[0016] An object of the present invention is to provide a hot runner system to improve the yield rate of injection molded products.

[0017] To achieve this object, the present invention adopts the following technical solutions:

[0018] A hot runner system comprises a valve needle and the anti-backflow structure, wherein the valve needle is connected to the top of the first body and is used for injection molding a first colloid and / or a second colloid.

[0019] Beneficial effects of the present invention:

[0020] The present invention discloses an anti-backflow structure. The anti-backflow structure comprises a first main body, wherein a first flow channel and a second flow channel are arranged inside the first main body, and the first flow channel and the second flow channel can respectively inject a first colloid and a second colloid; the first flow channel extends from the top end of the first main body to its bottom end along the axial direction of the first main body; the second flow channel spirally extends from the top end of the first main body to the bottom end thereof, and forms a second glue inlet hole at the top end of the first main body, and forms a second glue outlet hole at the bottom end of the first main body, and the aperture of the second glue outlet hole is smaller than the aperture of the second glue inlet hole. The structure can complete the injection of two colloids at the same time, and the second flow channel spirally extends from the top end of the first main body to its bottom end, so that the second colloid can flow to the second glue outlet hole more evenly and slowly, and the aperture of the second glue outlet hole is smaller than the aperture of the second glue inlet hole, which can effectively prevent the phenomenon of the colloid flowing out of the second glue outlet hole and then flowing back, thereby solving the problem of welding marks on the product caused by backflow.

[0021] The invention also discloses a hot runner system, which uses the above structure to effectively improve the yield rate of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is an isometric view of the backflow prevention structure provided by the present invention;

[0023] Figure 2 It is a structural schematic diagram of the anti-backflow structure provided by the present invention;

[0024] Figure 3 is a top view of the backflow prevention structure provided by the present invention;

[0025] Figure 4 It is a bottom view of the backflow prevention structure provided by the present invention.

[0026] In the figure:

[0027] 10. first body; 11. first flow channel; 111. first glue inlet hole; 12. second flow channel; 121. second glue inlet hole; 122. second glue outlet hole; 123. drainage slope; 13. positioning groove;

[0028] 20. Second main body; 21. Third flow channel. DETAILED DESCRIPTION

[0029] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0030] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0032] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0033] This embodiment provides a backflow prevention structure, such as Figure 1-Figure 4 As shown, the structure includes a first main body 10, and a first flow channel 11 and a second flow channel 12 are arranged inside the first main body 10, and the first flow channel 11 and the second flow channel 12 can respectively inject the first colloid and the second colloid; the first flow channel 11 extends from the top end of the first main body 10 to its bottom end along the axial direction of the first main body 10; the second flow channel 12 spirally extends from the top end of the first main body 10 to its bottom end, and forms a second glue outlet hole 122 at the top end of the first main body 10, and the aperture of the second glue outlet hole 122 is smaller than the aperture of the second glue inlet hole 121.

[0034] In this structure, the first flow channel 11 and the second flow channel 12 can respectively correspond to the injection molding of two different types of first colloid and second colloid; in addition, the second flow channel 12 spirally extends from the top end of the first body 10 to its bottom end, so that the second colloid can flow more evenly and slowly to the second glue outlet hole 122, and the aperture of the second glue outlet hole 122 is smaller than the aperture of the second glue inlet hole 121, thereby effectively preventing the colloid from flowing back after flowing out of the second glue outlet hole 122, thereby solving the problem of welding marks on the product caused by backflow.

[0035] It should be noted here that during the injection molding process, one end of the anti-backflow structure is connected to the valve needle, and the other end is connected to the cavity (injection mold). The valve needle is driven to move by the driving member to open and close the glue port to complete the injection molding. When the hot runner of the prior art is used to inject two-color colloids, it is necessary to withdraw the valve needle after completing the injection molding of one colloid, and then inject the second colloid. However, a certain suction force will be generated during the withdrawal of the valve needle, so the problem of colloid backflow will occur. In this embodiment, after the injection molding of the first colloid is completed, the first colloid exists in the cavity. At this time, the valve needle needs to withdraw to the initial position before the second colloid can be injected. Since the aperture of the second glue outlet hole 122 is smaller than the aperture of the second glue inlet hole 121, and the viscosity of the colloid itself will produce a certain resistance, it is inconvenient for the first colloid to enter the second flow channel 12 from the second glue outlet hole 122. Therefore, the limited suction force generated by the withdrawal of the valve needle cannot cause the first colloid to flow back, thereby avoiding the problem of weld marks caused by colloid backflow. It is further explained that in this embodiment, the two different colloids can be two colloids with different viscosities, different colors or different temperatures, and the difference of the colloids is not specifically limited in this embodiment. In addition, when used, the first colloid can be injected alone, the second colloid can be injected alone, or the first and second colloids can be injected simultaneously.

[0036] like Figure 2 As shown, the interior of the second flow channel 12 is provided with a drainage slope 123, and the angle between the drainage slope 123 and the top surface of the first body 10 is 25°-30°. By setting the drainage slope 123, it can play a guiding role in the flow process of the second colloid, and setting the angle between it and the first body 10 to 25°-30° can better drain and guide the second colloid, thereby avoiding the situation where the second colloid flows too fast or too slowly, thereby ensuring a good injection molding effect. It should be noted here that, in this embodiment, the angle between the drainage slope 123 and the top surface of the first body 10 is any angle between 25°-30°. In other embodiments, this value can be appropriately adjusted according to actual needs to ensure good injection molding efficiency.

[0037] like Figure 1-Figure 4 As shown, multiple second flow channels 12 are evenly and evenly arranged along the circumference of the first body 10. By setting multiple second flow channels 12, it is ensured that the injection molding process has a sufficient amount of glue output. Multiple second flow channels 12 are evenly and spaced along the circumference to ensure the uniformity of glue output, avoiding the situation where there is too much or too little second colloid in some parts, which leads to poor injection molding effect. It should be noted here that in this embodiment, there are three second flow channels 12. In other embodiments, the number of second flow channels 12 is adjusted according to actual needs, and no specific limitation is made in this embodiment.

[0038] To simplify the overall structure, Figure 1-Figure 4As shown, the first flow channel 11 is arranged at the center of the first body 10, and the plurality of second flow channels 12 are arranged at the periphery of the first flow channel 11, and the first flow channel 11 and the second flow channels 12 are not connected. The first flow channel 11 is arranged at the center of the first body 10, which is convenient for connecting with the valve needle of the hot runner. On this basis, it is also convenient to evenly distribute the plurality of second flow channels 12 around the periphery of the first flow channel 11 along the circumferential direction, while also ensuring the aesthetics of the structure; and the first flow channel 11 and the second flow channel 12 are not connected, which ensures that when a single colloid is injected, the colloid will not flow into other flow channels, ensuring a good injection molding effect.

[0039] To facilitate the assembly of the structure on the valve needle, Figure 2 As shown, the first flow channel 11 forms a first glue inlet hole 111 at the top of the first body 10, and a positioning groove 13 is provided between the first glue inlet hole 111 and the plurality of second flow channels 12. By providing the positioning groove 13, it is convenient to fix the first body 10 and the valve needle and other structures, thereby improving the convenience of use. In addition, the first glue inlet hole 111 is provided in the positioning groove 13, that is, when the first colloid is injected, the first colloid will not overflow into the second glue inlet hole 121.

[0040] like Figure 1-Figure 4 As shown, the anti-backflow structure also includes a second body 20, which is located at one end of the first body 10 where the second glue outlet hole 122 is provided, and the second body 20 is provided with a third flow channel 21 along its axial direction, and the third flow channel 21 is connected to the first flow channel 11, and the first colloid can flow to the third flow channel 21, and flow from the third flow channel 21 to the inside of the cavity, and the diameter of the second body 20 is smaller than the diameter of the first body 10, and the second colloid can flow to the periphery of the second body 20, and then flow to the inside of the cavity. In this structure, the first flow channel 11 is connected to the third flow channel 21, which means that the flow path of the first colloid is extended, thereby increasing the return distance of the first colloid. When the valve needle is withdrawn, the suction force generated will drive a small part of the first colloid to flow back, but the first colloid will not flow out from the first glue inlet hole 111; in addition, the diameter of the second body 20 is smaller than the diameter of the first body 10, ensuring that the second body 20 will not hinder the second colloid from flowing out of the second glue outlet hole 122, and after flowing out of the second flow channel 12, it will flow to the periphery of the second body 20, thereby indirectly entering the cavity, thereby ensuring a good use effect. In addition, when the second colloid is injected and the valve needle is withdrawn again, the structure of the second flow channel 12 can also prevent the mixed colloid of the first colloid and the second colloid from flowing back again.

[0041] like Figure 4 As shown, the first body 10 and the second body 20 are coaxially arranged. This structure can ensure good concentricity and prevent the problem of valve needle wear caused by eccentricity from affecting the sealing of the glue port.

[0042] To ensure the quality of glue, Figure 1 and Figure 2 As shown, the diameter of the second body 20 gradually decreases in the direction away from the first body 10. According to Bernoulli's principle, when a fluid flows in a pipe, the smaller the diameter of the pipe, the faster the flow rate of the fluid. Therefore, the diameter of the second body 20 gradually decreases in the direction close to the end of the third flow channel 21, thereby increasing the dispensing speed of the first colloid, thereby producing a good injection molding effect.

[0043] In addition, the first body 10 and the second body 20 are an integrally formed structure. This arrangement can facilitate processing and reduce overall manufacturing costs.

[0044] This embodiment also provides a hot runner system, which includes a valve needle and the above-mentioned anti-backflow structure, wherein the valve needle is connected to the top of the first body 10, and the valve needle is positioned and installed through the positioning groove 13, and is used for injection molding of the first colloid and / or the second colloid. By applying the above-mentioned anti-backflow structure, the hot runner system can effectively solve the problem of colloid backflow during the injection molding process, thereby improving the product yield.

[0045] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A backflow prevention structure, characterized in that: include: A first body (10) is provided with a first flow channel (11) and a second flow channel (12) therein, wherein the first flow channel (11) and the second flow channel (12) are capable of respectively injecting a first colloid and a second colloid; the first flow channel (11) extends from the top end of the first body (10) to the bottom end thereof along the axial direction of the first body (10); the second flow channel (12) spirally extends from the top end of the first body (10) to the bottom end thereof, and forms a second glue inlet hole (121) at the top end of the first body (10), and forms a second glue outlet hole (122) at the bottom end of the first body (10); the aperture of the second glue outlet hole (122) is smaller than the aperture of the second glue inlet hole (121).

2. The backflow prevention structure according to claim 1, characterized in that: A drainage slope (123) is provided inside the second flow channel (12), and the included angle between the drainage slope (123) and the top surface of the first body (10) is 25°-30°.

3. The backflow prevention structure according to claim 2, characterized in that: A plurality of second flow channels (12) are evenly spaced along the circumference of the first body (10).

4. The backflow prevention structure according to claim 3, characterized in that: The first flow channel (11) is arranged at the center of the first body (10), and the plurality of second flow channels (12) are arranged at the periphery of the first flow channel (11), and the first flow channel (11) is not connected to the plurality of second flow channels (12).

5. The backflow prevention structure according to claim 4, characterized in that: The first flow channel (11) forms a first glue inlet hole (111) at the top end of the first body (10), and a positioning groove (13) is arranged between the first glue inlet hole (111) and the plurality of second flow channels (12).

6. The backflow prevention structure according to any one of claims 1 to 5, characterized in that: The anti-backflow structure further comprises a second body (20), the second body (20) being located at one end of the first body (10) provided with a second glue outlet hole (122), the second body (20) being provided with a third flow channel (21) along its axial direction, the third flow channel (21) being connected to the first flow channel (11), the first colloid being able to flow to the third flow channel (21), the diameter of the second body (20) being smaller than the diameter of the first body (10), the second colloid being able to flow to the periphery of the second body (20).

7. The backflow prevention structure according to claim 6, characterized in that: The first body (10) and the second body (20) are coaxially arranged.

8. The backflow prevention structure according to claim 7, characterized in that: The diameter of the second body (20) gradually decreases in a direction away from the first body (10).

9. The backflow prevention structure according to claim 7, characterized in that: The first body (10) and the second body (20) are integrally formed.

10. A hot runner system, characterized in that: It comprises a valve needle and an anti-backflow structure as claimed in any one of claims 1 to 9, wherein the valve needle is connected to the top end of the first body (10) and is used for injection molding a first colloid and / or a second colloid.

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