Needle valve type hot runner assembly

Abstract

The utility model belongs to the technical field of hot runners of injection molds, and particularly relates to a needle valve type hot runner assembly which comprises a splitter plate, a heat insulation pad is arranged on the upper surface of the splitter plate, a supporting frame is mounted on the heat insulation pad, heat dissipation holes are formed in the outer side of the supporting frame, positioning grooves are symmetrically formed in the inner wall of the supporting frame, and the heat dissipation holes are communicated with the positioning grooves. A servo motor is installed in the supporting frame, and a coupler is installed at the output end of the servo motor. The nut seat on the ball screw is rigidly fixed to the valve needle through the connecting frame, the rotating motion of the ball screw can be converted into the linear reciprocating motion of the valve needle, in the moving process of the nut seat, the sliding blocks on the two sides slide along the positioning grooves, the positions of the nut seat connecting frame and the valve needle can be limited in one step, and the service life of the valve needle is prolonged. And the stability degree and precision of the valve needle during operation are improved, so that the melt flow control precision is improved, and the quality of injection molding products of the needle valve type hot runner assembly is further improved.

Description

Technical Field

[0001] This utility model belongs to the field of hot runner technology for injection molds, specifically a needle valve type hot runner assembly. Background Technology

[0002] Hot runner systems use heating to keep the plastic in the runner and gate in a molten state. A hot runner system generally consists of several parts, including hot nozzles, manifolds, temperature control boxes, and accessories.

[0003] Existing valve-type hot runner assemblies are widely used in precision injection molding. Their valve needle driving method mainly relies on pneumatic cylinders or hydraulic cylinders. The valve needle is moved by air pressure or hydraulic pressure to control the opening and closing of the gate. Pneumatic drive is affected by air pressure fluctuations, and the valve needle repeatability is only ±0.1mm, which leads to incomplete gate closure and flash. Although the hydraulic system has slightly higher accuracy, oil leakage contaminates the melt. The high-precision linear reciprocating motion of the valve needle in the hot runner system is the core technology for achieving precision injection molding. Its role directly affects product quality, production efficiency and process controllability. Therefore, a needle valve type hot runner assembly is proposed to address the above problems. Utility Model Content

[0004] To overcome the shortcomings of existing technologies and address the problems existing in current equipment, this utility model proposes a needle valve type hot runner assembly.

[0005] The technical solution adopted by this utility model to solve its technical problem is a needle valve type hot runner assembly, including: a flow divider plate, a heat insulation pad provided on the upper surface of the flow divider plate, a support frame installed on the heat insulation pad, heat dissipation holes opened on the outer side of the support frame, positioning grooves symmetrically opened on the inner wall of the support frame, a servo motor installed inside the support frame, a coupling installed at the output end of the servo motor, a ball screw installed on the coupling, a nut seat threadedly connected to the ball screw, sliders connected to both sides of the nut seat, the sliders slidably connected inside the positioning grooves, a connecting frame fixedly connected to the bottom of the nut seat, a first water tank opened inside the support frame, a first water exchange pipe fixedly connected to the support frame, the first water exchange pipe extending into the first water tank, the first water tank being located outside the servo motor, during the movement of the nut seat, the sliders on both sides slide along the positioning grooves, which can further restrict the position of the nut seat, the connecting frame and the valve needle, improving the stability and accuracy of the valve needle during operation.

[0006] Preferably, the guide sleeve is internally threaded onto the flow divider plate. An embedded lubrication groove is formed inside the guide sleeve, and a self-lubricating bushing is installed inside the embedded lubrication groove. A wear-resistant layer is provided on the inner wall of the guide sleeve. The solid lubricant in the self-lubricating bushing, which is filled in the lubrication groove on the inner wall of the guide sleeve, is continuously released under the friction of the valve needle, forming a transfer film. This reduces the resistance of the valve needle in the linear movement within the hot nozzle, improves the smoothness of the linear movement of the valve needle, and avoids the resistance affecting the linear movement of the valve needle.

[0007] Preferably, a second water tank is provided inside the flow divider plate, and the second water tank is located outside the guide sleeve. A second water exchange pipe is fixedly connected to the flow divider plate, and one end of the second water exchange pipe extends into the interior of the second water tank. The condensate in the second water tank can be replaced through the second water exchange pipe, thereby ensuring that the self-lubricating bushing is cooled down and its temperature is controlled within a safe range, thus ensuring long-term self-lubrication.

[0008] Preferably, a diversion pipe is fixedly connected to the diversion plate, and a hot nozzle is installed inside the diversion plate. One end of the diversion pipe is connected to the hot nozzle. Plastic particles enter the diversion plate and the hot nozzle through the diversion pipe. The plastic particles are melted into a uniform melt by energizing the heater inside the hot nozzle.

[0009] Preferably, the hot nozzle is provided with a valve needle inside, the top end of the valve needle is connected to the bottom of the connecting frame, one end of the valve needle is located inside the guide sleeve, and the guide sleeve is located outside the valve needle, so that when the valve needle moves vertically, its left and right sway can be restricted, thereby improving the stability of the valve needle's vertical operation.

[0010] Preferably, one end of the hot nozzle is threaded with a pressure cap, and a heat insulation cap is installed on the outside of the pressure cap. One side of the heat insulation cap is connected to the hot nozzle. The first water exchange pipe and the second water exchange pipe are both equipped with control valves. The heat insulation cap can isolate the hot nozzle tip from the mold, thereby reducing heat loss.

[0011] The advantages of this utility model are: the nut seat on the ball screw is rigidly fixed to the valve needle through the connecting frame, which can convert the rotational motion of the ball screw into the linear reciprocating motion of the valve needle. During the movement of the nut seat, the sliders on both sides slide along the positioning groove, which can further restrict the position of the nut seat connecting frame and the valve needle, improve the stability and accuracy of the valve needle during operation, thereby improving the accuracy of melt flow control and thus improving the quality of injection molded products of needle valve type hot runner components.

[0012] The solid lubricant in the self-lubricating bushing filled in the lubrication groove of the guide sleeve of this utility model is continuously released under the friction of the valve needle, forming a transfer film. The condensate in the second water tank ensures that the lubricant is at a safe temperature, thereby reducing the resistance of the valve needle in the linear movement of the hot nozzle and preventing direct contact between the valve needle and the guide sleeve. This reduces wear on the surface of the valve needle, thereby extending the service life of the valve needle and, consequently, the service life of the needle valve hot runner assembly. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 This is a schematic diagram of the overall structure;

[0015] Figure 2 This is a schematic diagram of the overall structure in cross-section;

[0016] Figure 3 This is a schematic cross-sectional view of the drive component;

[0017] Figure 4 This is a schematic diagram of the cross-section of the manifold.

[0018] Figure 5 This is a schematic diagram of a hot nozzle.

[0019] In the diagram: 1. Diverter plate; 2. Heat insulation pad; 3. Support frame; 4. Heat dissipation hole; 5. Positioning groove; 6. Servo motor; 7. Ball screw; 8. Nut seat; 9. Slider; 10. Connecting frame; 11. First water tank; 12. First water exchange pipe; 13. Guide sleeve; 14. Self-lubricating bushing; 15. Wear-resistant layer; 16. Second water tank; 17. Second water exchange pipe; 18. Diverter pipe; 19. Hot nozzle; 20. Valve needle; 21. Heat insulation cap. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0021] Please see Figure 1-5As shown, a needle valve type hot runner assembly includes: a flow divider 1, a heat insulation pad 2 on the upper surface of the flow divider 1, a support frame 3 mounted on the heat insulation pad 2, heat dissipation holes 4 on the outer side of the support frame 3, positioning grooves 5 symmetrically opened on the inner wall of the support frame 3, a servo motor 6 installed inside the support frame 3, a coupling installed at the output end of the servo motor 6, a ball screw 7 mounted on the coupling, a nut seat 8 threadedly connected to the ball screw 7, sliders 9 connected to both sides of the nut seat 8, the sliders 9 slidably connected inside the positioning grooves 5, a connecting frame 10 fixedly connected to the bottom of the nut seat 8, a first water tank 11 opened inside the support frame 3, a first water exchange pipe 12 fixedly connected to the support frame 3, the first water exchange pipe 12 extending into the interior of the first water tank 11, and the first water tank 11 located outside the servo motor 6;

[0022] Existing valve-type hot runner assemblies are widely used in precision injection molding. Their valve needle actuation primarily relies on pneumatic or hydraulic cylinders, which suffer from poor transmission accuracy. However, the high-precision linear reciprocating motion of the valve needle 20 within the hot runner system is a core technology for achieving precision injection molding, directly impacting product quality, production efficiency, and process controllability. Therefore, a valve-type hot runner assembly is proposed. In practical use, a 400W medium-inertia motor 6 is selected. The servo motor 6 drives the ball screw 7 via a coupling. The ball screw 7 is selected with C5 precision and double nut preload. Because the internal thread of the nut seat 8 matches the thread on the ball screw 7, the rotation of the ball screw 7 adjusts the height of the nut seat 8 and the connecting bracket 10, thereby transmitting linear motion to the valve needle 20. The valve needle 20 retracts upwards, the gate opens, and the melt is injected. In the mold cavity, the valve needle 20 presses down on the gate seat, cutting off the melt flow. Thus, the nut seat 8 on the ball screw 7 is rigidly fixed to the valve needle 20 through the connecting frame 10, which can convert the rotational motion of the ball screw 7 into the linear reciprocating motion of the valve needle 20. During the movement of the nut seat 8, the sliders 9 on both sides slide along the positioning groove 5, which can further restrict the position of the nut seat 8, the connecting frame 10 and the valve needle 20, improving the stability and accuracy of the valve needle 20 during operation, thereby improving the accuracy of melt flow control and thus improving the quality of the injection molded product of the needle valve hot runner assembly. An annular first water tank 11 is set on the outside of the servo motor 6, which can reduce the temperature of the servo motor 6 and replace the water in the first water tank 11 through the first water replacement pipe 12, thereby preventing the servo motor 6 from overheating and affecting its normal operation.

[0023] Please see Figure 1-5As shown, a guide sleeve 13 is threadedly connected to the inside of the diverter plate 1. An embedded lubrication groove is formed inside the guide sleeve 13, and a self-lubricating bushing 14 is installed inside the embedded lubrication groove. A wear-resistant layer 15 is provided on the inner wall of the guide sleeve 13. A second water tank 16 is formed inside the diverter plate 1, located outside the guide sleeve 13. A second water exchange pipe 17 is fixedly connected to the diverter plate 1, with one end extending into the interior of the second water tank 16. A diverter is also fixedly connected to the diverter plate 1. Pipe 18, inside the diversion plate 1, a hot nozzle 19 is installed. One end of the diversion pipe 18 is connected to the hot nozzle 19. A valve needle 20 is installed inside the hot nozzle 19. The top of the valve needle 20 is connected to the bottom of the connecting frame 10. One end of the valve needle 20 is located inside the guide sleeve 13. One end of the hot nozzle 19 is threadedly connected to a pressure cap. A heat insulation cap 21 is installed on the outside of the pressure cap. One side of the heat insulation cap 21 is connected to the hot nozzle 19. Control valves are installed inside the first water exchange pipe 12 and the second water exchange pipe 17.

[0024] Driven by the servo motor 6 and the ball screw 7, the valve needle 20 reciprocates linearly along the inner hole of the guide sleeve 13. The condensate in the second water tank 16 can be replaced through the second water exchange pipe 17, thereby ensuring the cooling of the self-lubricating bushing 14 and keeping its temperature within a safe range, thus ensuring long-term self-lubrication. The solid lubricant in the self-lubricating bushing 14, which is filled in the lubrication groove on the inner wall of the guide sleeve 13, is continuously released under the friction of the valve needle 20, forming a transfer film. This reduces the resistance of the valve needle 20 in the linear movement within the hot nozzle 19 and prevents the valve needle 20 from directly contacting the guide sleeve 13, thereby reducing wear on the surface of the valve needle 20, extending the service life of the valve needle 20, and thus extending the service life of the needle valve hot runner assembly.

[0025] Working principle: Plastic granules enter the manifold 1 and the hot nozzle 19 through the manifold pipe 18. The heater inside the hot nozzle 19 heats the plastic granules into a uniform melt. The servo motor 6 drives the ball screw 7 via the coupling, adjusting the height of the nut seat 8 and the connecting frame 10. This transmits linear motion to the valve needle 20. The valve needle 20 retracts upwards, opening the gate and allowing the melt to enter the cavity. The valve needle 20 then presses down against the gate seat, cutting off the melt flow. Driven by the servo motor 6 and the ball screw 7, the valve needle 20 moves along the guide sleeve 1... The inner hole of the guide sleeve 13 makes a linear reciprocating motion. The solid lubricant in the self-lubricating bushing 14, which is filled in the lubrication groove of the inner wall of the guide sleeve 13, is continuously released under the friction of the valve needle 20, forming a transfer film. This reduces the resistance of the valve needle 20 in the linear motion of the hot runner 19, and prevents the valve needle 20 from directly contacting the guide sleeve 13. This reduces the wear on the surface of the valve needle 20, extends the service life of the valve needle 20, improves the smoothness of the valve needle 20's operation, reduces the wear of the servo motor 6, and thus extends the service life of the hot runner assembly. It can also improve the injection molding quality of the hot runner assembly.

[0026] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0027] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. A needle valve type hot runner assembly, characterized in that: include: A diverter plate (1) is provided with a heat insulation pad (2) on its upper surface. A support frame (3) is installed on the heat insulation pad (2). A heat dissipation hole (4) is opened on the outer side of the support frame (3). A positioning groove (5) is symmetrically opened on the inner wall of the support frame (3). A servo motor (6) is installed inside the support frame (3). A coupling is installed at the output end of the servo motor (6). A ball screw (7) is installed on the coupling. A nut seat (8) is threaded on the ball screw (7). A slider (9) is connected to both sides of the nut seat (8). The slider (9) is slidably connected inside the positioning groove (5). A connecting frame (10) is fixedly connected to the bottom of the nut seat (8). A first water tank (11) is opened inside the support frame (3). A first water exchange pipe (12) is fixedly connected to the support frame (3). The first water exchange pipe (12) extends into the interior of the first water tank (11). The first water tank (11) is located outside the servo motor (6).

2. The needle valve type hot runner assembly according to claim 1, characterized in that: The internal thread of the diverter plate (1) is connected to a guide sleeve (13), the inside of the guide sleeve (13) is provided with an embedded lubrication groove, the inside of the embedded lubrication groove is provided with a self-lubricating bushing (14), and the inner wall of the guide sleeve (13) is provided with a wear-resistant layer (15).

3. The needle valve type hot runner assembly according to claim 1, characterized in that: The diversion plate (1) has a second water tank (16) inside. The second water tank (16) is located outside the guide sleeve (13). A second water exchange pipe (17) is fixedly connected to the diversion plate (1). One end of the second water exchange pipe (17) extends into the interior of the second water tank (16).

4. A needle valve type hot runner assembly according to claim 1, characterized in that: A diversion pipe (18) is fixedly connected to the diversion plate (1), and a hot nozzle (19) is installed inside the diversion plate (1). One end of the diversion pipe (18) is connected to the hot nozzle (19).

5. A needle valve type hot runner assembly according to claim 4, characterized in that: The hot nozzle (19) is provided with a valve needle (20) inside. The top end of the valve needle (20) is connected to the bottom of the connecting frame (10), and one end of the valve needle (20) is located inside the guide sleeve (13).

6. A needle valve type hot runner assembly according to claim 5, characterized in that: One end of the hot nozzle (19) is threaded with a pressure cap, and a heat insulation cap (21) is installed on the outside of the pressure cap. One side of the heat insulation cap (21) is connected to the hot nozzle (19). The first water exchange pipe (12) and the second water exchange pipe (17) are both equipped with control valves.

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