A bicycle accessory injection molding device

Abstract

The application belongs to the technical field of injection molding, and particularly relates to a bicycle accessory injection molding device which comprises a quantitative feeder unit, a quantitative mechanism, a heating circulating unit, a discharging mechanism and a liquid material supply system. A jet pipe composed of an annular pipe and a vertical pipe is arranged in a tank body, cooperates with an upper reflux cavity to form a nitrogen closed loop circulation, and provides inert gas protection for raw materials. The quantitative mechanism drives the swing of a partition plate of upper and lower sealing plates through a linear motor, cooperates with a vibration module to realize volumetric precise supply of solid raw materials, and coils are arranged on the outer wall of a mixing box. The rotation of a feeding rod is driven by a hollow shaft through a guide groove, axial reciprocation is independently driven by a hydraulic rod, and the two movements are decoupled. The solid material quantitative mechanism and the liquid material pumping system share a controller, and automatic proportioning of solid-liquid is realized according to a preset formula.

Description

Technical Field

[0001] This invention belongs to the field of injection molding technology, and specifically relates to an injection molding device for bicycle parts. Background Technology

[0002] In the injection molding process of bicycle parts, the supply and pretreatment of raw materials directly affect the quality stability of the final product. Bicycle plastic parts have different requirements for raw material ratios, appearance quality, and mechanical properties depending on their application. For example, bicycle light housings require the addition of UV-resistant additives to improve weather resistance, mudguards require toughening agents to improve impact resistance, and gearbox housings need to ensure dimensional accuracy and wear resistance. In existing injection molding equipment, the ratio of solid raw materials largely relies on manual weighing and feeding, which limits operational efficiency and results in batch-to-batch ratio deviations. For formulation systems involving powders, granules, and liquid additives, manual operation makes it difficult to achieve precise real-time ratio control. Furthermore, when raw materials are stored and transported in open or semi-open environments, they come into contact with oxygen and moisture in the air, easily leading to moisture absorption and clumping or oxidative degradation. This results in decreased melt flowability, the formation of bubbles, silver streaks, or deterioration of mechanical properties within the product, affecting the appearance quality and service life of the bicycle parts.

[0003] In the mixing and conveying of molten material, conventional equipment typically uses resistance heaters installed on the outer wall of the mixing tank or feeding pipe for heating, with heat transferred from the outside in. However, for internal metal components such as moving stirring rods, shafts, and feeding rods, the surface temperature is often lower than the bulk material temperature. When the molten material comes into contact with these relatively cool moving parts, localized cooling and the formation of a condensation layer can easily occur. As the condensation layer thickens, the rotational or reciprocating resistance of the moving parts increases, not only increasing drive energy consumption but also potentially causing uneven mixing and poor conveying, and in severe cases, jamming of the moving parts or abnormal wear of mating surfaces. This problem is even more pronounced for products like bicycle parts that require frequent color changes and intermittent production. Therefore, how to reduce the risk of material condensation and solidification on the surface of moving parts through structural design is a crucial technical issue that needs attention in bicycle part injection molding equipment. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned technical problems existing in the existing injection molding equipment for bicycle parts, and provides an injection molding device with precise quantitative feeding and heating cycle functions, so as to improve the problems of insufficient solid raw material ratio accuracy, easy oxidation and moisture during feeding, need to improve the heating efficiency of raw material mixing, and easy material condensation and solidification on the surface of key moving parts, thereby improving the injection molding quality of bicycle parts.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a bicycle parts injection molding apparatus, comprising:

[0006] A quantitative feeder unit includes at least one tank. The top of the tank is provided with a feeding tank and a disc-shaped tank cover. An air jet pipe is fixed on the inner wall of the tank. The bottom of the air jet pipe is an annular pipe and connected to a vertical pipe at the top. The air jet pipe is connected to an external compressor through an air inlet pipe. A reflux chamber is provided at the top of the tank. The reflux chamber is connected to the air inlet of the compressor through a reflux pipe. A scraper is provided at the bottom of the tank, and a level gauge is installed on the side wall.

[0007] A metering mechanism is located below the discharge port of the tank and includes a storage cylinder, an upper sealing plate, and a lower sealing plate. Each sealing plate has a swingable partition, and the partition has a connecting port. Each partition is rotated by an independent linear motor that drives the gear on the swing rod through a rack and pinion. A vibration module is provided on the outer wall of the storage cylinder.

[0008] A heating circulation unit includes a mixing tank. A coil is embedded in the outer wall of the mixing tank. The tank contains a first stirring rod and a hollow rotating shaft. Both the first stirring rod and the hollow rotating shaft are made of induction heating metal material. A second stirring rod extends from the outer wall of the hollow rotating shaft. One end of the first stirring rod extends out and is fixed with a first sprocket. One end of the hollow rotating shaft extends out and is fixed with a second sprocket. The two sprockets are connected by a chain and driven to rotate synchronously by a stirring motor.

[0009] The discharge mechanism includes a feeding pipe, a feeding rod, and an extrusion head. The outer wall of the feeding pipe is wound with heating wire, and a seepage hole is opened on the side wall near one end of the hollow rotating shaft. The extrusion head is equipped with a one-way valve. The auger blade at the rear end of the feeding rod is slidably fitted into the guide groove at the front end of the hollow rotating shaft. The hydraulic rod of the hydraulic cylinder passes through the central through hole of the hollow rotating shaft, and its front end is connected to the end of the feeding rod through a relatively rotatable annular boss connecting part. The front end of the feeding pipe is connected to the extrusion pipe. A combined control valve is installed on the outer wall of the extrusion pipe, and its outlet is located in the return box. The return box is connected to the mixing box through a pipe.

[0010] The liquid supply system includes a pumping device and a flow meter, and shares a controller with each linear motor of the quantitative feeder unit.

[0011] It should be noted that the "induction heating metal material" refers to a metal material that can generate heat due to induced eddy currents under the action of an alternating electromagnetic field, such as carbon steel, ferromagnetic stainless steel, and other metal materials with good magnetic and electrical conductivity. When an alternating current is passed through the coil, an alternating electromagnetic field is generated. Induced eddy currents are generated inside the metal component located in this magnetic field, thereby generating heat.

[0012] Preferably, the quantitative feeding unit includes a first material tank, a second material tank, and a third material tank with identical structures, and the tank body of the three material tanks is the same as the first material tank. By setting multiple tanks with the same structure, different types of solid powders or granules, such as main ingredients, pigments, functional additives, etc., can be processed separately, realizing the independent storage and supply of multiple raw materials.

[0013] Preferably, the disc-shaped can lid has a through-hole annular cavity structure with an internal filter layer for gas-solid separation of air brought in with the raw materials during feeding, allowing the gas to escape and the material to fall into the can. The scraper rod is driven by a scraper motor and rotates at the bottom of the can to agitate the raw materials, reduce the possibility of powder bridging, and move them toward the discharge port.

[0014] Preferably, the annular pipe at the bottom of the jet pipe is integrally connected to the upper vertical pipe. Dry nitrogen enters the annular pipe through the inlet pipe and is then blown out through each vertical pipe, forming a bottom-up protective airflow within the tank. This keeps the raw material in an inert gas atmosphere, reducing the risk of oxidation and moisture absorption. A filter is installed inside the reflux chamber to intercept material powder carried by the recovered airflow, reducing the possibility of powder entering the compressor piping and causing blockage or damage. By supplying gas through the inlet pipe and recovering gas through the reflux chamber and reflux pipe, a closed-loop nitrogen circulation system is formed, conserving gas resources.

[0015] Preferably, the quantitative mechanism operates as follows: the upper sealing plate's partition swings under the drive of a linear motor, connecting the storage cylinder to the tank via its connecting port, allowing the raw material to fall into the storage cylinder. At this time, the lower sealing plate's partition is closed. During feeding, the vibration module is activated, promoting the filling of the storage cylinder with raw material through vibration, reducing the probability of cavities or bridging, and improving the accuracy of each portion of raw material volume. After feeding, the upper sealing plate's partition swings back to seal, cutting off the connection between the storage cylinder and the tank. At this point, the storage cylinder contains one portion of fixed-volume raw material. Subsequently, the lower sealing plate's partition swings open, connecting the storage cylinder to the mixing tank, allowing the raw material to fall into the mixing tank under gravity. By controlling the intervals and frequency of each linear motor's operation, the quantity of each solid raw material supplied can be controlled, enabling the proportioning of multiple raw materials.

[0016] Preferably, the portions of the feeding pipe, feeding rod, extrusion head, and hydraulic rod extending into the mixing tank are all made of induction-heating metal material. Thus, when an alternating current is applied to the coil on the outer wall of the mixing tank, not only the first stirring rod and the hollow rotating shaft act as heating elements, but the extended sections of the feeding pipe, feeding rod, extrusion head, and hydraulic rod also simultaneously generate induction heat. These components together form a three-dimensional thermal field surrounding the moving parts within the mixing tank and the discharge mechanism. Since these components themselves are heat sources, their surface temperatures can be maintained at a high level, reducing the risk of molten material solidifying on their surface. It should be noted that these components are all moving parts or parts that directly cooperate with moving parts. If solidification occurs on their surfaces, it may cause jamming, wear, or damage. Making them heat sources is a technical means to reduce the probability of this problem occurring.

[0017] Preferably, the hydraulic rod has a heat-insulating section on the rod segment between the annular boss connection and the hydraulic cylinder body. This heat-insulating section is made of a low thermal conductivity material (such as ceramics, high-temperature resistant engineering plastics, etc.) or adopts a hollow thin-walled structure to reduce the heat conduction cross-sectional area. Its function is to reduce the heat conduction along the hydraulic rod axis to the hydraulic cylinder body, thereby reducing the risk of excessive hydraulic cylinder body temperature leading to aging of hydraulic seals and deterioration of hydraulic oil, and protecting the hydraulic system.

[0018] Preferably, the outer shell of the mixing box is made of a non-magnetic metal material (such as austenitic stainless steel). It should be noted that non-magnetic metal materials are less prone to induced heating in alternating electromagnetic fields. This reduces the phenomenon of the mixing box shell itself heating up due to the magnetic field generated by the coil, allowing more magnetic field energy to act on the internal heating components, thus improving heating efficiency and reducing the surface temperature of the shell. Simultaneously, the outer wall of the mixing box is wrapped with an insulating layer covering the outer side and bottom. This layer serves both as thermal insulation and as a shield against electromagnetic field attenuation, reducing heat loss.

[0019] Preferably, temperature sensors are installed inside the mixing tank, at the combined control valve, and at the feeding pipe. Each temperature sensor feeds back the temperature signal to the controller in real time. The controller independently adjusts the current flowing through the coil and the power of the heating wire based on the preset process temperature and the actual temperature of each zone. It should be noted that this zoned collaborative temperature control strategy enables more uniform and controllable temperature of the molten material throughout the entire process from mixing and conveying to extrusion, reducing both the possibility of localized overheating leading to material decomposition and the possibility of localized low temperatures causing condensation.

[0020] Preferably, during the retracting stroke of the feed rod, the negative pressure generated behind the extruder head causes the one-way valve on the extruder head to open. The molten material in the mixing tank, under the pressure difference, enters the feed pipe through the seepage hole and is drawn into the storage chamber in front of the extruder head, completing the material replenishment action. During the forward stroke of the feed rod, the one-way valve closes under the pressure of the molten material, pushing the molten material in the storage chamber out through the extrusion tube. The entire working cycle is similar to the suction and injection process of a syringe, with clear division of labor between the suction and injection strokes, and the one-way valve ensures that the molten material can only flow unidirectionally towards the mold.

[0021] Preferably, the combined control valve is a combination of a pressure relief valve and a one-way valve. When the injection pressure is within the set range, the valve remains closed; when the pressure inside the extrusion tube exceeds the set value, the combined control valve opens in one direction, discharging a portion of the molten material into the return tank to reduce the risk of pipeline overpressure damage. The remaining material discharged into the return tank is piped back to the mixing tank for recycling. The combined control valve can be inspected or replaced by disassembling the return tank casing.

[0022] Preferably, the hollow shaft penetrating the wall of the mixing box and the space between the central through hole of the hollow shaft and the hydraulic rod are provided with a high-temperature resistant rotary sealing structure (such as a high-temperature resistant skeleton oil seal, graphite packing seal or mechanical seal, etc.) to reduce the possibility of leakage of molten material and gas from the rotation gap.

[0023] Preferably, the controller triggers the liquid supply system to pump in the corresponding amount of liquid material when the solid metering mechanism completes the feeding of a certain quantity of material, according to the set solid-liquid ratio. It should be noted that the liquid ratio can be adjusted by changing the pumping speed or pumping frequency per unit time of the liquid pumping device to adapt to different product formulation requirements.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] In terms of structural design, multiple moving parts that come into contact with the molten material, such as the stirring rod, hollow rotating shaft, feeding pipe, feeding rod, extrusion head, and hydraulic rod extension section, are all made of induction heating metal materials. These components are synchronously heated by an alternating electromagnetic field generated by the same set of external coils, forming a three-dimensional thermal field surrounding the moving parts within the mixing tank and discharge mechanism. This design allows the surfaces of the moving parts to maintain a high temperature, preventing localized cooling and solidification of the molten material upon contact. This reduces the risk of jamming or abnormal wear due to the accumulation of condensate on the surface of the moving parts, ensuring stable operation of the equipment over long periods during bicycle parts production. The accompanying hydraulic rod insulation section, the non-magnetic outer shell and insulation layer of the mixing tank, and the temperature sensors distributed in the mixing tank, feeding pipe, and combined control valves, working together to control temperature in designated zones, further guarantee the engineering feasibility of this thermal field design.

[0026] For material discharge, the extrusion head is equipped with a one-way valve, and a seepage hole communicating with the mixing box is opened on the side wall of the feeding pipe. Combined with the axial reciprocating motion of the feeding rod, this forms a syringe-like suction and injection cycle. The injection volume is controlled by the stroke of the feeding rod, which is beneficial for precise control of the injection volume during the injection molding of bicycle parts. The rotational motion of the feeding rod is driven by a hollow rotating shaft through a guide groove and the sliding engagement of the auger blades. The axial reciprocating motion is independently driven by a hydraulic rod through a rotating connection of an annular boss. The two sets of motions are decoupled, avoiding the complex sealing problems of the hydraulic cylinder rotating along with the hydraulic cylinder in traditional structures.

[0027] In the raw material supply stage, solid raw materials are supplied using a volumetric quantitative method with a storage cylinder and upper and lower sealing plates that oscillate, combined with a vibration module to promote filling, ensuring controllable volume of each batch of raw material. Liquid additives are directly injected into the mixing tank after being metered by a pump and flow meter. The solid and liquid supply systems share a common controller, which can automatically interlock and proportion according to preset formulas for different parts of bicycle components (such as headlight housings, mudguards, and gearbox housings), providing a feasible technical means for the precise supply of multi-component and multi-phase raw materials. At the same time, the nitrogen injection and reflux filtration closed-loop circulation system installed in the tank provides inert gas protection for the raw materials inside, reducing the possibility of oxidation and moisture absorption during storage and loading, which helps to ensure the appearance quality and mechanical properties of bicycle component products. Attached Figure Description

[0028] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0030] Figure 2 This is a cross-sectional view of the powder container in this invention;

[0031] Figure 3 This is a schematic diagram of the metering mechanism in this invention;

[0032] Figure 4 This is a schematic diagram of the internal structure of the quantitative mechanism in this invention;

[0033] Figure 5 This is a cross-sectional view of the heating circulation unit in this invention;

[0034] Figure 6 This is a schematic diagram of the hollow rotating shaft in this invention;

[0035] Figure 7 This is a schematic diagram of the feeding pipe in this invention;

[0036] In the diagram: 10. Quantitative feeder unit; 11. First feed tank; 12. Second feed tank; 13. Third feed tank; 14. Loading tank;

[0037] 111. Disc-shaped lid; 112. Tank body; 113. Level gauge; 114. Reflux chamber;

[0038] 20. Protective gas unit; 21. Inlet pipe; 22. Jet pipe; 23. Drive mechanism; 24. Scraper rod;

[0039] 30. Measuring mechanism; 31. Storage cylinder; 32. Vibration module; 33. Lower sealing plate; 34. Upper sealing plate; 35. Partition plate; 36. Discharge port; 37. Sealing ring; 38. Connecting port; 39. Swing rod;

[0040] 40. Heating and circulating unit; 41. Mixing box; 42. First stirring rod; 43. First sprocket; 44. Hollow rotating shaft; 441. Guide groove; 45. Second stirring rod; 46. Second sprocket;

[0041] 50. Transmission box unit; 51. Housing; 52. Hydraulic cylinder body; 521. Hydraulic rod; 522. Connecting part; 53. Agitator motor;

[0042] 60. Discharge mechanism; 61. Feeding pipe; 62. Feeding rod; 621. Screw blade; 63. Extrusion head; 64. Heating wire; 65. Seepage hole; 66. Extrusion tube; 67. Return box. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] Example 1

[0045] like Figures 1 to 7 As shown, a bicycle parts injection molding device is disclosed. This device can be used for the injection molding production of bicycle parts such as headlight housings, mudguards, gearbox housings, and handlebars.

[0046] In this implementation plan:

[0047] A bicycle parts injection molding apparatus includes: a quantitative feeding unit 10, including at least one tank 112, a feeding tank 14 and a disc-shaped tank cover 111 on the top of the tank 112, an air jet pipe 22 fixed on the inner wall of the tank 112, the bottom of the air jet pipe 22 is an annular pipe and the top is connected to a vertical pipe, the air jet pipe 22 is connected to an external compressor through an air inlet pipe 21, a return chamber 114 is provided at the upper part of the tank 112, the return chamber 114 is connected to the air inlet of the compressor through a return pipe, a scraper 24 is provided at the bottom of the tank 112, and a material level gauge 113 is installed on the side wall;

[0048] The metering mechanism 30 is located below the discharge port of the tank 112 and includes a storage cylinder 31, an upper sealing plate 34 and a lower sealing plate 33. Each sealing plate is provided with a swingable partition 35. The partition 35 has a connecting port 38. Each partition 35 is driven to rotate by an independent linear motor through a rack and pinion drive on the gear on the swing rod 39. The outer wall of the storage cylinder 31 is provided with a vibration module 32.

[0049] The heating circulation unit 40 includes a mixing tank 41, on which a coil is embedded in the outer wall. Inside, there is a first stirring rod 42 and a hollow rotating shaft 44, both of which are made of induction heating metal material. A second stirring rod 45 extends from the outer wall of the hollow rotating shaft 44. One end of the first stirring rod 42 extends out and is fixed with a first sprocket 43. One end of the hollow rotating shaft 44 extends out and is fixed with a second sprocket 46. The two sprockets are connected by a chain and driven to rotate synchronously by a stirring motor 53.

[0050] The discharge mechanism 60 includes a feeding pipe 61, a feeding rod 62, and an extrusion head 63. A heating wire 64 is wound around the outer wall of the feeding pipe 61, and a seepage hole 65 is opened on the side wall near the hollow rotating shaft 44. A one-way valve is provided on the extrusion head 63. The auger blade 621 at the rear end of the feeding rod 62 is slidably fitted into the guide groove 441 at the front end of the hollow rotating shaft 44. The hydraulic rod 521 of the hydraulic cylinder 52 passes through the central through hole of the hollow rotating shaft 44, and its front end is connected to the end of the feeding rod 62 through a relatively rotatable annular boss connecting part 522. The front end of the feeding pipe 61 is connected to the extrusion pipe 66. A combined control valve is installed on the outer wall of the extrusion pipe 66, and its outlet is located in the return box 67. The return box 67 is connected to the mixing box 41 through a pipe.

[0051] The liquid supply system, including pumping devices and flow meters, shares a controller with each linear motor of the quantitative feeder unit 10.

[0052] Furthermore:

[0053] In an optional embodiment, the quantitative feeding unit 10 includes a first material tank 11, a second material tank 12, and a third material tank 13 with identical structures, and the tank body of the three material tanks is the tank body 112; the disc-shaped tank cover 111 is an annular cavity structure with a through-hole in the middle and a filter layer is provided inside; the scraper rod 24 is driven by a scraper motor and rotates at the bottom of the tank body 112.

[0054] In this implementation plan:

[0055] Three identical tanks are provided to store and supply different types of solid raw materials. For example, the first tank 11 can store base plastic granules (such as polycarbonate PC granules), the second tank 12 can store color masterbatches, and the third tank 13 can store powdered functional additives (such as UV inhibitors, flame retardants, etc.). Independent supply from the three tanks allows for online proportioning of various raw materials without pre-mixing, improving production flexibility.

[0056] It should be noted that the disc-shaped can lid 111 is designed with a through-hole annular cavity structure, and its internal filter layer can be made of multi-layer stainless steel wire mesh or sintered porous material. When the raw material enters the can body 112 from the feeding tank 14, the air brought in with the raw material can be discharged through the filter layer, while the solid material is intercepted and falls into the can body, realizing gas-solid separation and reducing dust overflow.

[0057] Driven by a scraper motor, the scraper rod 24 rotates at the bottom of the tank 112. The rod can be designed to be arc-shaped or inclined to match the contour of the tank bottom. When the raw material becomes bridging due to moisture absorption or prolonged standing, the rotation of the scraper rod can disrupt the force balance between the raw materials, restore their flow, and promote the movement of the raw materials toward the discharge port.

[0058] Furthermore:

[0059] In an optional embodiment, the annular tube at the bottom of the jet pipe 22 is integrally connected with the upper vertical tube. After the dry nitrogen enters the annular tube through the air inlet pipe 21, it is blown out evenly from each vertical tube, forming a protective airflow from bottom to top inside the tank. A filter element is provided inside the return chamber 114.

[0060] In this embodiment:

[0061] The jet pipe 22 adopts a structure combining a bottom annular pipe and multiple vertical pipes, which can disperse nitrogen gas to various areas within the tank 112, reducing the occurrence of protection dead zones. The annular pipe is located near the bottom of the tank, and the vertical pipes extend upwards along the tank wall. The nitrogen gas flows from bottom to top, forming a countercurrent contact with the falling direction of the raw material, which helps to improve the protection effect.

[0062] The filter element inside the reflux chamber 114 can be made of materials such as fiber filter cartridges or microporous filter membranes. When the recovered gas carries trace amounts of dust into the reflux chamber, the filter element intercepts the dust, and the clean gas returns to the compressor inlet through the reflux pipe, forming a closed-loop cycle. This design saves nitrogen resources and reduces the risk of dust entering the compressor and causing equipment damage.

[0063] Furthermore:

[0064] In an optional embodiment, when the partition 35 of the upper sealing plate 34 swings open, its connecting port 38 connects the storage cylinder 31 to the tank body 112, at which time the partition 35 of the lower sealing plate 33 is closed; after the partition 35 of the upper sealing plate 34 swings back to seal, the partition 35 of the lower sealing plate 33 swings open again, so that the storage cylinder 31 is connected to the mixing box 41; the vibration module 32 is started when feeding.

[0065] In this embodiment:

[0066] The quantitative mechanism 30 operates in three steps: feeding, volume determination, and discharging. During feeding, only the upper sealing plate 34 is opened, and the raw material in the tank 112 falls into the storage cylinder 31 under the assistance of gravity and the scraper rod 24. The vibration module 32 starts synchronously, causing the storage cylinder 31 to vibrate at high frequency and low amplitude. The raw material particles rearrange under the vibration, eliminating internal voids and bridging, making the material filling in the storage cylinder more compact and improving the accuracy of each portion of raw material volume. During volume determination, the upper sealing plate 34 closes, completely isolating the storage cylinder 31 from the tank 112; at this point, the cylinder contains one portion of raw material at a fixed volume. During discharging, only the lower sealing plate 33 opens, and the raw material falls into the mixing box 41.

[0067] It should be noted that the partition 35 opens and closes by swinging rather than by linear pulling, which is advantageous for opening and closing within a limited installation space. The swing rod 39 converts the linear motion of the linear motor into the rotational motion of the partition, resulting in a compact structure and fast response speed.

[0068] Furthermore:

[0069] In an optional embodiment, the portions of the feeding pipe 61, feeding rod 62, extrusion head 63, and hydraulic rod 521 that extend into the mixing box 41 are all made of induction heating metal material, forming a three-dimensional thermal field around the moving parts together with the first stirring rod 42 and the hollow rotating shaft 44; the hydraulic rod 521 has a heat insulation section on the rod section between the annular boss connection portion 522 and the hydraulic cylinder body 52.

[0070] In this embodiment:

[0071] The feeding pipe 61, feeding rod 62, extrusion head 63, and the extension section of the hydraulic rod 521 are all made of the same induction heating metal material (such as carbon steel, alloy steel, or other magnetic and conductive metals) as the first stirring rod 42, so that they can also generate heat due to induced eddy currents in an alternating electromagnetic field. These components are all moving parts or parts that directly cooperate with moving parts, making them heat sources. This reduces the possibility of condensation and solidification when the molten material comes into contact with the surface of these components due to the high surface temperature of the components.

[0072] It should be noted that the heat insulation section on the hydraulic rod 521 can be implemented using ceramic sleeves, high-temperature resistant engineering plastic spacers, or hollow thin-walled structures. The purpose is to establish a thermal barrier between the heating section of the hydraulic rod and the hydraulic cylinder body, reducing the conduction of heat along the rod body towards the hydraulic cylinder body, thereby protecting the hydraulic seals and hydraulic oil and extending the service life of the hydraulic system.

[0073] Furthermore:

[0074] In an optional embodiment, the outer shell of the mixing box 41 is made of a non-magnetic metal material, and its outer wall is wrapped with an insulating interlayer covering the outer side wall and the bottom side.

[0075] In this embodiment:

[0076] The outer shell of the mixing box 41 can be made of non-magnetic metal materials such as austenitic stainless steel (e.g., 304 or 316L stainless steel). Non-magnetic materials are not easily induced to heat up in alternating electromagnetic fields. Therefore, the magnetic field energy generated by the coil is not easily lost on the outer shell, but rather acts more on the internal heating components, which helps to improve heating efficiency. At the same time, the fact that the outer shell does not heat up also reduces the surface temperature of the equipment.

[0077] The insulation interlayer can be filled with high-temperature resistant insulation materials such as rock wool and aluminum silicate fiber, and covered with a metal protective plate. The interlayer covers the outer wall and bottom of the mixing box, reducing heat loss to the surrounding environment and saving energy. At the same time, the insulation interlayer also has a certain degree of attenuation and shielding effect on electromagnetic fields.

[0078] Furthermore:

[0079] In an optional embodiment, temperature sensors are respectively installed in the mixing box 41, at the combined control valve, and at the feeding pipe 61. Each temperature sensor feeds back the temperature signal to the controller, and the controller independently adjusts the current of the coil and the power of the heating wire 64 according to the temperature of each zone.

[0080] In this embodiment:

[0081] Temperature sensors can be thermocouples or platinum resistance thermometers. The sensor in the mixing tank 41 monitors the bulk material temperature, the sensor at the combined control valve monitors the temperature of the molten material about to be injected into the mold, and the sensor at the feeding pipe 61 monitors the temperature of the plasticizing section. These three sensors form a multi-point temperature measurement network. The controller compares the temperature values ​​from each point with preset process temperature parameters and adjusts the coil current to control the induction heating power and the heating wire 64 current to control the auxiliary heating power, achieving zoned and coordinated temperature control. This control method helps to make the temperature more uniform throughout the entire process from mixing to extrusion, reducing the possibility of localized overheating decomposition or localized low-temperature condensation.

[0082] Furthermore:

[0083] In an optional embodiment, when the feed rod 62 retracts, the one-way valve of the extrusion head 63 opens, and the molten material in the mixing box 41 enters the feed pipe 61 through the seepage hole 65 and is sucked into the storage chamber in front of the extrusion head 63; when the feed rod 62 moves forward, the one-way valve closes, and the molten material in the storage chamber is pushed out through the extrusion pipe 66.

[0084] In this embodiment:

[0085] The working cycle of the dispensing mechanism 60 simulates the suction and injection actions of a medical syringe. During the suction stroke, the hydraulic rod 521 retracts, driving the feeding rod 62 and the extrusion head 63 to move backward. A negative pressure is formed behind the extrusion head 63, and the one-way valve on it opens under the pressure difference. Driven by the pressure difference, the molten material in the mixing tank 41 enters the feeding pipe 61 through the seepage hole 65 and passes through the one-way valve to fill the gradually increasing storage cavity in front of the extrusion head 63. It should be noted that the size and number of seepage holes 65 can be designed according to factors such as the viscosity of the molten material and the diameter of the feeding rod to ensure smooth material replenishment.

[0086] During the injection stroke, the hydraulic rod 521 extends, pushing the feed rod 62 and the extrusion head 63 forward. At this time, the molten material is pressurized, the one-way valve closes under pressure, and the molten material in the storage chamber is pushed out and injected into the injection mold cavity through the extrusion tube 66. The injection volume is controlled by the stroke of the feed rod.

[0087] Furthermore:

[0088] In an optional embodiment, the combined control valve is a combination of a pressure relief valve and a check valve, which opens in one direction when the pressure in the extrusion tube 66 exceeds a set value, discharging excess molten material into the return box 67; the hollow rotating shaft 44 is provided with a high-temperature resistant rotary sealing structure at the wall of the mixing box 41 and between the central through hole of the hollow rotating shaft 44 and the hydraulic rod 521.

[0089] In this embodiment:

[0090] The combined control valve integrates mechanical pressure relief and one-way flow functions. The pressure relief section sets a safe pressure threshold. When the pressure in the extrusion tube 66 abnormally rises and exceeds the threshold due to increased mold flow resistance, excessive injection speed, or other reasons, the pressure relief valve opens. The one-way valve section ensures that the molten material can only be discharged from the extrusion tube, preventing the backflow of air or impurities. Excess molten material discharged enters the return tank 67 for temporary storage, and is then returned to the mixing tank 41 for recycling via the bottom pipe by gravity or an auxiliary pump.

[0091] It should be noted that the high-temperature rotary seal structure can be selected in different forms depending on the operating temperature and pressure conditions. For example, a high-temperature skeleton oil seal or mechanical seal can be used where the hollow shaft 44 penetrates the wall of the mixing tank 41. A high-temperature O-ring seal combined with a wear-resistant guide sleeve, or a flexible graphite packing seal, can be used between the central through hole of the hollow shaft 44 and the hydraulic rod 521. These sealing methods are all conventional technologies in this field and can be selected and applied according to the actual working conditions.

[0092] Furthermore:

[0093] In an optional embodiment, the controller triggers the liquid supply system to pump in a corresponding amount of liquid material when the solid metering mechanism has completed a certain number of feedings, according to a set solid-liquid ratio, and the liquid material pumping speed or frequency is adjustable.

[0094] In this embodiment, the controller can store various formulation parameters, and the operator can set the required solid-liquid ratio through the human-machine interface. For example, in the production of plastic products, if the formulation requires a 50:1 ratio of base plastic granules to liquid additives, the controller will trigger the liquid pumping system to pump in one part of liquid additive according to the flow meter setting after the solid metering mechanism completes 50 feeding actions. The liquid pumping volume can be adjusted by regulating the peristaltic pump speed or the plunger pump stroke frequency to adapt to the formulation requirements of different products.

[0095] Working principle and usage process of this invention:

[0096] During operation, solid raw materials (such as plastic granules, masterbatches, and powdered additives) are stored in the first material tank 11, the second material tank 12, and the third material tank 13, respectively. Dry nitrogen gas, introduced into each tank 112 through the inlet pipe 21, is blown upwards through the jet pipe 22, creating an inert gas protective atmosphere and reducing the risk of oxidation and moisture absorption of the raw materials. The gas inside the tank is filtered through the upper reflux chamber 114 and then returned to the compressor through the reflux pipe, forming a closed-loop cycle.

[0097] When feeding is required, the corresponding metering mechanism 30 at the bottom of each tank 112 starts working. The partition 35 of the upper sealing plate 34 swings open under the drive of an independent linear motor, connecting the storage cylinder 31 to the tank 112 via the connecting port 38, allowing the raw material to fall into the storage cylinder 31. Simultaneously, the vibration module 32 starts, and the scraper rod 24 rotates, promoting material filling. After feeding is complete, the partition 35 of the upper sealing plate 34 closes and seals, leaving a fixed volume of solid raw material in the storage cylinder 31. Then, the partition 35 of the lower sealing plate 33 opens, allowing the raw material to fall into the mixing box 41. By controlling the number of strokes of each linear motor, the proportions of various solid raw materials can be achieved.

[0098] The liquid supply system pumps the liquid additive directly into the mixing tank 41 according to the set amount through independent pipelines and flow meters, and shares a controller with the quantitative feeder unit to achieve interlocking and proportioning.

[0099] In the mixing tank 41, an alternating current is passed through an embedded coil on the outer wall, causing the induction heating metal components such as the first stirring rod 42, the hollow rotating shaft 44, and the second stirring rod 45 to heat themselves, directly heating the material. The stirring motor 53 drives the first stirring rod 42 and the hollow rotating shaft 44 to rotate synchronously via a sprocket and chain. The first stirring rod 42 and the second stirring rod 45 work together to stir the mixture, making it a melt. At the same time, the feeding pipe 61, the feeding rod 62, the extrusion head 63, and the extension section of the hydraulic rod 521 also act as heating elements, forming a three-dimensional thermal field around the moving parts, reducing the risk of the molten material solidifying on its surface. Temperature sensors inside the mixing tank 41, at the combined control valve, and at the feeding pipe 61 provide real-time temperature feedback, and the controller coordinates the adjustment of the coil current and the power of the heating wire 64 in different zones.

[0100] The molten material enters the feed pipe 61 through the seepage hole 65. During the suction stroke when the hydraulic rod 521 retracts, the one-way valve of the extrusion head 63 opens, and the molten material is drawn into the storage chamber in front of the extrusion head. During the injection stroke when the hydraulic rod 521 extends, the one-way valve closes, and the molten material in the storage chamber is injected into the injection mold through the extrusion pipe 66. The rotation of the feed rod 62 is driven by the hollow rotating shaft 44 through the cooperation of the guide groove 441 and the auger blade 621, realizing simultaneous rotational plasticization and axial reciprocating injection.

[0101] When the pressure inside the extrusion tube 66 rises abnormally, the combined control valve opens, and excess molten material is discharged into the return box 67 and guided back to the mixing box 41 for recycling. The hollow rotating shaft 44 passes through the wall of the mixing box 41, and the high-temperature resistant rotary sealing structure between the central through hole of the hollow rotating shaft 44 and the hydraulic rod 521 is used to reduce the possibility of molten material and gas leakage.

[0102] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bicycle parts injection molding device, characterized in that, include: The quantitative feeder unit (10) includes at least one tank (112). The top of the tank (112) is provided with a feeding tank (14) and a disc-shaped tank cover (111). The inner wall of the tank (112) is fixed with a jet pipe (22). The bottom of the jet pipe (22) is an annular pipe and the top is connected to a vertical pipe. The jet pipe (22) is connected to an external compressor through an air inlet pipe (21). The upper part of the tank (112) is provided with a return chamber (114). The return chamber (114) is connected to the air inlet of the compressor through a return pipe. The bottom of the tank (112) is provided with a scraper (24), and the side wall is equipped with a level gauge (113). The metering mechanism (30) is located below the discharge port of the tank (112) and includes a storage cylinder (31), an upper sealing plate (34) and a lower sealing plate (33). Each sealing plate is provided with a swingable partition (35). The partition (35) has a connecting port (38). Each partition (35) is driven to rotate by an independent linear motor through a rack and pinion drive on the gear on the swing rod (39). The outer wall of the storage cylinder (31) is provided with a vibration module (32). The heating circulation unit (40) includes a mixing tank (41), with a coil embedded in its outer wall and a first stirring rod (42) and a hollow rotating shaft (44) inside. Both are made of induction heating metal material. A second stirring rod (45) extends out from the outer wall of the hollow rotating shaft (44). One end of the first stirring rod (42) extends out and is fixed with a first sprocket (43). One end of the hollow rotating shaft (44) extends out and is fixed with a second sprocket (46). The two sprockets are connected by a chain and driven to rotate synchronously by a stirring motor (53). The discharge mechanism (60) includes a feeding pipe (61), a feeding rod (62) and an extrusion head (63). The outer wall of the feeding pipe (61) is wound with a heating wire (64). A seepage hole (65) is opened on the side wall near the hollow rotating shaft (44). A one-way valve is provided on the extrusion head (63). The auger blade (621) at the rear end of the feeding rod (62) is slidably fitted into the guide groove (441) at the front end of the hollow rotating shaft (44). The hydraulic rod (521) of the hydraulic cylinder (52) passes through the central through hole of the hollow rotating shaft (44). The front end is connected to the end of the feeding rod (62) through a relatively rotatable annular boss connecting part (522). The front end of the feeding pipe (61) is connected to the extrusion pipe (66). A combined control valve is installed on the outer wall of the extrusion pipe (66). Its outlet is located in the return box (67). The return box (67) is connected to the mixing box (41) through a pipe. The liquid supply system, including pumping devices and flow meters, shares a controller with each linear motor of the quantitative feeder unit (10).

2. The bicycle parts injection molding apparatus according to claim 1, characterized in that: The quantitative feeding unit (10) includes a first material tank (11), a second material tank (12) and a third material tank (13) with the same structure. The tank body of the three material tanks is the tank body (112). The disc-shaped tank cover (111) is an annular cavity structure with a through-hole in the middle and a filter layer inside. The scraper rod (24) is driven by a scraper motor and rotates at the bottom of the tank body (112).

3. The bicycle parts injection molding apparatus according to claim 1, characterized in that: The annular tube at the bottom of the jet pipe (22) is integrally connected with the vertical tube above. After the dry nitrogen enters the annular tube through the air inlet pipe (21), it is blown out evenly from each vertical tube, forming a protective airflow from bottom to top in the tank. The return chamber (114) is equipped with a filter.

4. The bicycle parts injection molding apparatus according to claim 1, characterized in that: When the partition (35) of the upper sealing plate (34) swings open, its connecting port (38) connects the storage cylinder (31) with the tank body (112), at which time the partition (35) of the lower sealing plate (33) is closed; after the partition (35) of the upper sealing plate (34) swings back to seal, the partition (35) of the lower sealing plate (33) swings open again, so that the storage cylinder (31) connects with the mixing box (41); the vibration module (32) is started when feeding.

5. The bicycle parts injection molding apparatus according to claim 1, characterized in that: The portions of the feeding pipe (61), feeding rod (62), extrusion head (63), and hydraulic rod (521) that extend into the mixing box (41) are all made of induction heating metal material, forming a three-dimensional thermal field around the moving parts together with the first stirring rod (42) and the hollow rotating shaft (44); the hydraulic rod (521) has a heat insulation section on the rod section between the annular boss connection part (522) and the hydraulic cylinder body (52).

6. The bicycle parts injection molding apparatus according to claim 5, characterized in that: The outer shell of the mixing box (41) is made of non-magnetic metal material, and its outer wall is wrapped with a heat-insulating interlayer covering the outer side wall and the bottom side.

7. The bicycle parts injection molding apparatus according to claim 6, characterized in that: Temperature sensors are installed in the mixing box (41), at the combined control valve and at the feeding pipe (61). Each temperature sensor feeds back the temperature signal to the controller. The controller independently adjusts the current of the coil and the power of the heating wire (64) according to the temperature of each zone.

8. The bicycle parts injection molding apparatus according to claim 1, characterized in that: When the feed rod (62) retracts, the one-way valve of the extrusion head (63) opens, and the molten material in the mixing box (41) enters the feed pipe (61) through the seepage hole (65) and is sucked into the storage chamber in front of the extrusion head (63); when the feed rod (62) moves forward, the one-way valve closes, and the molten material in the storage chamber is pushed out through the extrusion pipe (66).

9. The bicycle parts injection molding apparatus according to claim 1, characterized in that: The combined control valve is a combination of a pressure relief valve and a check valve. When the pressure in the extrusion tube (66) exceeds the set value, it opens in one direction to discharge excess molten material into the return box (67). The hollow rotating shaft (44) is provided with a high-temperature resistant rotary sealing structure at the wall of the mixing box (41) and between the central through hole of the hollow rotating shaft (44) and the hydraulic rod (521).

10. The bicycle parts injection molding apparatus according to claim 1, characterized in that: According to the set solid-liquid ratio, when the solid metering mechanism completes a certain number of feedings, the controller triggers the liquid supply system to pump in the corresponding amount of liquid material, and the liquid material pumping speed or frequency is adjustable.

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