Needle valve type hot runner injection mold with ring gate

Abstract

The invention provides a needle valve type hot runner injection mold with an annular gate. An inner valve needle and an outer valve needle are arranged between a female mold and a male mold. The inner valve needle moves along with the female mold and is matched with the male mold insert on the male mold during mold closing, the position of a middle hole of a product is positioned, and the two sides of the middle hole are injection molding areas. The outer valve needle is arranged on the outer side of the inner valve needle in a sleeving mode and controlled by a driving part to move up and down relative to the inner valve needle, when the outer valve needle moves downwards, the pouring gate can be blocked, molten materials in the hot runner are prevented from leaking from the pouring gate, and the driving part controls the outer valve needle to block the pouring gate so that the injection molding process of the molten materials can be achieved. The invention provides a novel ring gate injection molding device and scheme, the molding of a product with a middle hole can be effectively realized, the structure is simple, the operation is simple and easy, and a stable injection molding effect is achieved.

Description

Technical Field

[0001] The invention relates to a hot runner injection mold, in particular to a needle valve type hot runner injection mold with an annular gate. Background Art

[0002] Needle valve hot runner injection molding is an efficient and precise plastic processing method in modern injection molding technology. On the basis of traditional hot runner, a needle valve control system is added to accurately control the flow of plastic by opening and closing the needle valve, thereby achieving efficient molten plastic injection. When the gate of this mold is opened, the molten plastic enters the mold cavity through the gate for molding. Under the action of pressure, the plastic will enter the product cavity from the runner through the gate to fill the mold cavity. After the pressure is maintained, the valve needle will close the gate through the control of the oil cylinder or the air cylinder.

[0003] In traditional needle valve hot runner molds, circular gates are the most widely used. Circular gates can be directly poured on the surface of the product, and the structure is relatively simple. However, due to the structural characteristics of products on the market, some products need to form a hole in the middle of the gate. Traditional needle valve injection molds cannot achieve stable forming of the middle hole, so a new needle valve ring gate structure needs to be designed to meet such product requirements. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a needle valve hot runner injection mold with an annular gate, comprising a female mold and a male mold, a cavity is formed between the female mold and the male mold, and male mold inserts are provided on the surfaces of the male mold and the female mold;

[0005] The nozzle assembly is arranged on the side of the female mold opposite to the male mold. The bottom center of the nozzle assembly has a ring gate for discharging plastic particles and a hot runner for flowing plastic particles.

[0006] An inner valve needle is arranged in the center of the hot runner, one end of which is connected to the female mold and moves with the female mold, and the other end is connected to the male mold insert;

[0007] An outer valve needle, which is sleeved on the outer side of the inner valve needle and is used to isolate the inner valve needle from the molten material in the hot runner. The end of the outer valve needle extends between the gate and the inner valve needle and cooperates with the inner edge of the gate to block the connection between the hot runner and the gate; and:

[0008] A driving member, whose fixed end is connected to the mother mold and whose driving end is connected to the outer valve needle, the outer valve needle is driven by the driving member to move up and down relative to the inner valve needle to enter or leave the blocking position between the gate and the inner valve needle.

[0009] Furthermore, the mother mold includes a mounting plate, a diverter plate and a mother mold core arranged from top to bottom, and the driving member and the inner valve needle are connected in the mounting plate.

[0010] Furthermore, a positioning hole is provided at the center of the end of the inner valve needle, and an ejector pin inserted into the positioning hole is provided at the end of the male mold insert.

[0011] Furthermore, the positioning hole and the ejector pin are tapered structures with clearance fit to maintain the coaxiality of the inner valve needle and the male mold insert.

[0012] Furthermore, the inner valve needle and the side of the male mold insert form matching positioning step surfaces.

[0013] Furthermore, the driving member is an air cylinder or an oil cylinder, the cylinder body of which is arranged in the mounting plate, and the piston in the cylinder body controls the outer valve needle to move up and down.

[0014] Furthermore, a support plate is installed on the top of the mounting plate by bolts, and the support plate is used to stabilize the position of the inner valve needle. One end of the inner valve needle away from the gate passes through the center of the cylinder body and is connected to the bottom of the support plate.

[0015] Furthermore, the nozzle assembly includes a nozzle body installed in the mother mold, a bushing arranged between the nozzle body and the outer valve needle, and a nozzle head arranged between the bushing and the nozzle body, and the inner side of the bushing is provided with a contact edge abutting against the outer valve needle.

[0016] Furthermore, a guiding inclined surface offset toward the gate is provided on the inner side of the bushing at a position not in contact with the outer valve needle, so as to guide the molten material in the hot runner to the gate.

[0017] Furthermore, a threaded portion is provided on the outer side of the nozzle head for docking with the nozzle body.

[0018] The present invention provides a needle valve type hot runner injection mold with an annular gate, wherein an inner valve needle and an outer valve needle are arranged between the mother mold and the male mold. The inner valve needle moves with the mother mold, and cooperates with the male mold insert on the male mold when the mold is closed to locate the middle hole of the product, and the two sides of the middle hole are the injection molding area. The outer valve needle is sleeved on the outside of the inner valve needle, and is controlled by a driving component to move up and down relative to the inner valve needle. When the outer valve needle moves down, it will block the gate position to prevent the molten material in the hot runner from leaking from the gate. The injection molding process of the molten material is realized by controlling the outer valve to block the gate through the driving component. The present invention provides a new annular gate injection molding equipment and solution, which can effectively realize the molding of products with a middle hole, and has a simple structure, easy operation, and a stable injection molding effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a needle valve hot runner injection mold with an annular gate of the present invention;

[0020] Figure 2It is a schematic diagram of the connection between the upper mold and the lower mold;

[0021] Figure 3 It is a schematic diagram of the connection between the inner valve needle and the outer valve needle and the female mold;

[0022] Figure 4 It is a cross-sectional schematic diagram of the upper mold and the lower mold when the mold is closed, in which the outer valve needle is in a state of closing the gate;

[0023] Figure 5 It is a cross-sectional schematic diagram of the upper mold and the lower mold when the mold is closed, in which the outer valve needle is in the state of opening the gate;

[0024] Figure 6 It is a cross-sectional schematic diagram when the upper mold and the lower mold are separated.

[0025] Figure numerals: female mold 1, male mold 2, nozzle assembly 3, gate 4, hot runner 5, mounting plate 6, diverter plate 7, female mold core 8, male mold insert 9, inner valve needle 10, outer valve needle 11, drive member 12, cylinder body 13, piston 14, liner 15, first pressure plate 16, first convex ring 17, support plate 18, second convex ring 19, second pressure plate 20, nozzle body 21, bushing 22, nozzle head 23, contact edge 24, guide slope 25, threaded portion 26, positioning hole 27, ejector pin 28. DETAILED DESCRIPTION

[0026] like Figures 1 to 3 The needle valve hot runner injection mold with an annular gate shown in the figure comprises a female mold 1 and a male mold 2, and the female mold 1 and the male mold 2 are controlled to move relative to each other to form a cavity between the female mold 1 and the male mold 2. A nozzle assembly 3 is arranged on the side of the female mold 1 opposite to the male mold 2, and the bottom center of the nozzle assembly 3 has an annular gate 4 for discharging plastic particles and a hot runner 5 for flowing plastic particles. The heat flow connects the gate 4 with the injection molding machine, and the melted plastic particles are discharged from the gate 4 at the bottom of the nozzle assembly 3 through the hot runner 5 to form a product in the cavity.

[0027] The mother mold 1 is a rectangular block structure as a whole, including a mounting plate 6, a diverter plate 7 and a mother mold core 8 arranged from top to bottom. The diverter plate 7 is provided with a diverter flow channel connected to the hot runner 5, which can transfer the molten material from the injection molding machine to the hot runner 5 of the nozzle assembly 3, ensuring that the molten material can be transferred to the cavity.

[0028] An inner valve needle 10 is provided at the center of the hot runner 5, and the molten material will flow from the inner valve needle 10 and the inner side of the nozzle assembly 3 to the gate 4. One end of the inner valve needle 10 is fixedly connected to the female mold 1 and moves with the female mold 1. The end face of the male mold 2 is provided with a male mold insert 9, which is located in the center of the cavity. The other end of the inner valve needle 10 extends out of the gate 4 and contacts with the male mold insert 9 during mold closing to define the position of the middle hole of the product. Specifically, a positioning hole 27 is provided at the center of the end of the inner valve needle 10, and an ejector pin 28 is provided at the end of the male mold insert 9 to be inserted into the positioning hole 27. The positioning hole 27 and the ejector pin 28 are conical structures with clearance fit, which can effectively ensure the coaxiality of the inner valve needle 10 and the male mold insert 9. The inner valve needle 10 and the side of the male mold insert 9 form a matching positioning step surface, which fits tightly during mold closing to prevent the molten material from entering the middle hole.

[0029] An outer valve needle 11 is also provided in the hot runner 5. The outer valve needle 11 is annular and sleeved on the outer side of the inner valve needle 10, and is used to isolate the inner valve needle 10 from the molten material in the hot runner 5. The end of the outer valve needle 11 extends between the gate 4 and the inner valve needle 10, and cooperates with the inner edge of the gate 4 to block the connection between the hot runner 5 and the gate 4, and prevent the molten material in the hot runner 5 from flowing out of the gate 4. The outer valve needle 11 is connected to the output end of a driving member 12, and the outer valve needle 11 is driven by the driving member 12 to move up and down relative to the inner valve needle 10 to enter or leave the blocking position between the gate 4 and the inner valve needle 10.

[0030] The driving member 12 is an air cylinder or an oil cylinder, and its cylinder body 13 is fixedly arranged in the mounting plate 6, and the piston 14 in the cylinder body 13 controls the outer valve needle 11 to move up and down. By setting the operation program of the driving member 12, the gate 4 can be opened and closed at each molding stage of the product. The cylinder body 13 is also provided with an inner liner 15 and a first pressing plate 16. The top of the outer valve needle 11 is provided with a first convex ring 17. The inner liner 15 is pressed on the top of the outer valve needle 11, and the first convex ring 17 is clamped between the piston 14 and the inner liner 15; the first pressing plate 16 is pressed on the top of the inner liner 15, and applies a downward pressing force to the inner liner 15 to ensure the tightness of the connection between the outer valve needle 11 and the piston 14.

[0031] The female mold 1 is also provided with a support plate 18, which is fastened to the top of the mounting plate 6 by bolts. The support plate 18 is used to stabilize the position of the inner valve needle 10. The end of the inner valve needle 10 away from the gate 4 passes through the center of the cylinder body 13 and is connected to the bottom of the support plate 18. The top of the inner valve needle 10 is provided with a second convex ring 19, and the support plate 18 is provided with a slot for the second convex ring 19 to be installed. The top of the second convex ring 19 is crimped with a second pressing plate 20 to stabilize the connection between the inner valve needle 10 and the support plate 18. Furthermore, the cylinder body 13 is fixedly connected to the support plate 18, and the support plate 18 provides support for the cylinder body 13. When assembling the entire female mold, the inner valve needle 10, the cylinder body 13 and the support plate 18 can be assembled into a complete module first, and then installed as a whole on the top of the mounting plate 6 without the need for repositioning, which has the advantage of easy disassembly.

[0032] like Figure 3 As shown, the nozzle assembly 3 includes a nozzle body 21 installed in the mother mold 1, a bushing 22 arranged between the nozzle body 21 and the outer valve needle 11, and a nozzle head 23 arranged between the bushing 22 and the nozzle body 21. The inner side of the bushing 22 is provided with a contact edge 24 that abuts against the outer valve needle 11. The contact edge 24 extends axially along the outer side of the outer valve needle 11, and exerts a certain resistance when the outer valve needle 11 moves vertically, thereby guiding the movement trajectory of the outer valve needle 11, so that it can stably extend into the gate 4 during the downward movement. Further, the inner side of the bushing 22 is provided with a guide slope 25 that deviates toward the gate 4 at a position that does not contact the outer valve needle 11. The end size of the guide slope 25 is smaller than the size of the gate 4. The molten material in the hot runner 5 is guided by the guide slope 25 and can stay at the gate 4 position more accurately, waiting for the outer valve needle 11 to move up to open the gate 4 for injection.

[0033] The nozzle head 23 is used to fix the position of the bushing 22 in the nozzle assembly 3. In the axial direction of the inner valve needle 10, the end of the bushing 22 is pressed between the nozzle body 21 and the bushing 22; in the radial direction, the bushing 22 is pressed between them to stabilize the position of the bushing 22. Furthermore, the outer side of the nozzle head 23 is provided with a threaded portion 26 that is connected to the nozzle body 21, and the nozzle head 23 is fixed to the inner side of the nozzle body 21 by threaded connection.

[0034] Combination Figures 4 to 6 The process of injection molding using the mold provided by the present invention is as follows:

[0035] S1. Mold closing: The inner valve needle 10 is driven by the female mold 1 to move downward until the inner valve needle 10 is mated with the male mold insert 9; the driving member 12 controls the outer valve needle 11 to move downward to seal the gate 4, so that the gate 4 is in a closed state to prevent the molten material in the hot runner 5 from flowing out from the gate 4.

[0036] S2. Injection molding: Keep the inner valve needle 10 and the male mold insert 9 in cooperation, the driving part 12 controls the outer valve needle 11 to move upward, open the isolation state of the gate 4 and the hot runner 5, and the molten material in the hot runner 5 flows through the gate 4 until the entire cavity is filled.

[0037] S3. Cooling: The mold is cooled, and the molten material in the cavity is solidified and formed under low temperature conditions; the middle valve needle is kept in contact with the male mold insert 9, and the drive member 12 controls the outer valve needle 11 to move down and seal the gate 4, applying a certain pressure to the molten material in the cavity to prevent the unformed material from shrinking.

[0038] S4. Mold opening: When the material in the cavity is completely fixed, the female mold 1 drives the inner valve needle 10 and the outer valve needle 11 as well as the molded product to separate from the surface of the male mold 2, waiting for the next mold closing step cycle.

[0039] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A needle valve hot runner injection mold with an annular gate, characterized in that: include: A female mold (1) and a male mold (2), wherein a mold cavity is formed between the female mold (1) and the male mold (2), and male mold inserts (9) are provided on the surfaces of the male mold (2) and the female mold (1); The nozzle assembly (3) is arranged on the side of the female mold (1) opposite to the male mold (2), and the bottom center of the nozzle assembly (3) has an annular gate (4) for discharging plastic particles and a hot runner (5) for flowing plastic particles. An inner valve needle (10) is arranged at the center of the hot runner (5), one end of which is connected to the female mold (1) and moves with the female mold (1), and the other end of which is butt-jointed with the male mold insert (9); an outer valve needle (11), which is sleeved on the outer side of the inner valve needle (10) and is used to isolate the inner valve needle (10) from the molten material in the hot runner (5); the end of the outer valve needle (11) extends between the gate (4) and the inner valve needle (10) and cooperates with the inner edge of the gate (4) to block the communication between the hot runner (5) and the gate (4); and: A driving member (12) has a fixed end connected to the mother mold (1) and a driving end connected to the outer valve needle (11). The outer valve needle (11) is driven by the driving member (12) to move up and down relative to the inner valve needle (10) to enter or leave the blocking position between the gate (4) and the inner valve needle (10).

2. A needle valve hot runner injection mold with an annular gate as claimed in claim 1, characterized in that: The mother mold (1) comprises a mounting plate (6), a diverter plate (7) and a mother mold core (8) arranged from top to bottom, and the driving member (12) and the inner valve needle (10) are connected inside the mounting plate (6).

3. A needle valve hot runner injection mold with an annular gate as claimed in claim 1, characterized in that: A positioning hole (27) is provided at the center of the end of the inner valve needle (10), and an ejector pin (28) inserted into the positioning hole (27) is provided at the end of the male mold insert (9).

4. A needle valve hot runner injection mold with an annular gate as claimed in claim 3, characterized in that: The positioning hole (27) and the ejector pin (28) are conical structures with clearance fit, so as to maintain the coaxiality of the inner valve needle (10) and the male mold insert (9).

5. A needle valve hot runner injection mold with an annular gate as claimed in claim 3, characterized in that: The inner valve needle (10) and the side of the male mold insert (9) form matching positioning step surfaces.

6. A needle valve hot runner injection mold with an annular gate as claimed in claim 2, characterized in that: The driving member (12) is an air cylinder or an oil cylinder, and its cylinder body (13) is arranged in the mounting plate (6). The piston (14) in the cylinder body (13) controls the outer valve needle (11) to move up and down.

7. A needle valve hot runner injection mold with an annular gate as claimed in claim 6, characterized in that: A support plate (18) is installed on the top of the mounting plate (6) by means of bolts. The support plate (18) is used to stabilize the position of the inner valve needle (10). One end of the inner valve needle (10) away from the gate (4) passes through the center of the cylinder body (13) and is connected to the bottom of the support plate (18).

8. The needle valve hot runner injection mold with an annular gate according to claim 1, characterized in that: The nozzle assembly (3) comprises a nozzle body (21) installed in a mother mold (1), a sleeve (22) arranged between the nozzle body (21) and an outer valve needle (11), and a nozzle head (23) arranged between the sleeve (22) and the nozzle body (21), wherein the inner side of the sleeve (22) is provided with a contact edge (24) that abuts against the outer valve needle (11).

9. A needle valve hot runner injection mold with an annular gate as claimed in claim 8, characterized in that: A guiding inclined surface (25) offset toward the gate (4) is provided on the inner side of the bushing (22) at a position not in contact with the outer valve needle (11) so as to guide the molten material in the hot runner (5) to the gate (4).

10. The needle valve hot runner injection mold with an annular gate according to claim 8, characterized in that: The outer side of the nozzle head (23) is provided with a threaded portion (26) that is connected to the nozzle body (21).

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