Extrusion molding equipment for PVC plastic pipe production

Abstract

The application relates to the field of PVC plastic pipe processing equipment, in particular to an extrusion forming equipment for PVC plastic pipe production, which comprises a rack, a material pipe fixedly connected to the upper end face of the rack, a mounting ring coaxially connected to the outer side wall of the front end of the material pipe, and a die head coaxially arranged at the front end of the material pipe. The die head is provided with a locking hole, a plurality of pressure holes corresponding to the locking hole and penetrating through the inner and outer sides of the outer side wall of the material pipe, a sliding block and an elastic metal sheet arranged in the pressure holes, a first inclined surface on the sliding block and a second inclined surface in the locking hole, high pressure in the material pipe during equipment operation makes the elastic metal sheet deform and push the sliding block, the pre-tightening force of the die head is strengthened under the action of the first inclined surface and the second inclined surface, an insertion groove is arranged, the die head can be installed only by being inserted and then rotated, pressure dynamic locking and quick disassembly and assembly of the die head are realized.

Description

Technical Field

[0001] This invention relates to the field of PVC plastic pipe processing equipment, specifically to an extrusion molding equipment for PVC plastic pipe production. Background Technology

[0002] PVC plastic pipe extrusion equipment is an important device in factories producing plastic pipes. Filler is injected into the extrusion chamber through the feed hopper. Multiple heating devices heat the filler to a viscous molten state. Power from the motor is transmitted to the screw via a reducer, causing it to rotate. The rotating screw pushes the molten filler to the outlet, where it is then extruded and discharged. In practical applications, different dies need to be changed according to the different specifications and sizes of the products to meet production needs. The existing dies are fixed to the discharge pipe using flanges and bolts, which is inconvenient for operators to change dies of different specifications.

[0003] To address the aforementioned issues, existing technologies offer several solutions. For instance, utility model patent CN202121530771.3 provides a twin-screw extruder with an easily replaceable die head. This application discloses the following solution: a connecting ring is provided between the discharge pipe and the die head to connect the die head and the discharge pipe. The die head and the connecting ring are fixedly connected, and the end of the connecting ring away from the die head is slidably sleeved on the circumferential outer wall of the discharge pipe. A snap-fit ​​assembly is provided between the connecting ring and the discharge pipe to fix the connecting ring and the discharge pipe. In use, the connection between the connecting ring and the discharge pipe is adjusted by adjusting the snap-fit ​​assembly. When the die head needs to be replaced, only the connection relationship between the snap-fit ​​assembly and the discharge pipe needs to be adjusted to complete the replacement of the entire die head. This achieves the effect of facilitating the replacement of different die heads by the operator and improving work efficiency. However, this solution has certain limitations in practical use: the snap-fit ​​assembly will generate mechanical friction when the mold head is repeatedly disassembled and reassembled. At the same time, the high temperature environment will accelerate the oxidation and fatigue of the metal parts, resulting in wear of the snap-fit ​​block size, increased gap of the snap-fit ​​groove, and decreased elasticity of the spring. After long-term use, the snap-fit ​​assembly may not be able to lock completely, resulting in a larger gap between the connecting ring and the discharge pipe, which will affect the sealing of the mold head installation. This will cause the molten PVC filler to seep out along the gap between the mold head and the discharge pipe, forming a hard shell waste that cannot be reused after cooling. Summary of the Invention

[0004] The purpose of this invention is to provide an extrusion molding equipment for the production of PVC plastic pipes, so as to solve the problem that the die head is inconvenient to replace in the existing extrusion molding equipment for the production of PVC plastic pipes, and at the same time solve the problem that the sealing surface of the die head and the extruder wears after multiple assembly, resulting in the failure of the sealing surface and the inability to completely seal.

[0005] To achieve the above objectives, the present invention provides the following technical solution: An extrusion molding device for producing PVC plastic pipes includes a frame. A material pipe is fixedly connected to the upper surface of the frame, and an extrusion screw is coaxially rotatably mounted inside the material pipe. The device is characterized in that an installation ring is coaxially fixedly connected to the outer wall of the front end of the material pipe, and a die head is coaxially disposed at the front end of the material pipe. The die head includes a forming section and an installation section, which are coaxially arranged and located in front of the installation section. An installation hole is provided in the installation section, the inner diameter of which is larger than the outer diameter of the installation ring. The installation ring is coaxially fitted into the installation hole. Multiple locking holes are provided on the outer wall of the installation section, each of which penetrates both the inner and outer sides of the installation section. The die head has multiple locking holes evenly distributed around its central axis. Multiple pressure holes are provided on the outer wall of the material tube, penetrating both the inner and outer sides of the tube. Each locking hole corresponds to a pressure hole. A slider is slidably connected within each pressure hole, with one end extending outside the tube and the other end inside the pressure hole. The end of the slider inside the pressure hole is elastically connected to the material tube. When the die head is connected to the material tube, the slider extends into the locking hole and fits against the rear sidewall of the locking hole. The front end face of the mounting ring fits against the front inner wall of the mounting hole.

[0006] By coaxially fixing a mounting ring to the outer wall of the front end of the tube, and dividing the die head into a forming section and a mounting section, a mounting hole with an inner diameter slightly larger than the outer diameter of the mounting ring is opened in the mounting section, allowing the mounting ring to be coaxially fitted into the mounting hole. This achieves initial coaxial positioning of the die head and the tube. Based on this, locking holes are evenly distributed along the circumference of the outer wall of the mounting section, penetrating both its inner and outer sides. Correspondingly, pressure holes of the same type are set along the same circumferential trajectory on the outer wall of the tube, with a sliding block connected to each pressure hole. The end of the slider located in the pressure hole is elastically connected to the tube. When the die head and the tube are connected, the slider automatically extends into the corresponding locking hole under the drive of elastic force and fits tightly against the rear side wall of the locking hole. This, combined with the front of the mounting ring... The seamless fit between the end face and the inner wall of the mounting hole forms a double axial limiting structure, effectively restricting the axial displacement of the die head. When disassembling the die head, simply use a special tool to press the slider to disengage it from the locking hole to easily remove the die head. This design, through the cooperation of the elastic slider and the locking hole, eliminates the need for complex bolt disassembly or flange connection, allowing for quick installation and locking of the die head, significantly improving the convenience and efficiency of die head replacement. At the same time, the double fit structure between the mounting ring and the mounting hole, and between the slider and the locking hole, minimizes the gap between the material tube and the die head, effectively preventing molten PVC from seeping out from the connection and causing waste. In addition, the evenly distributed locking holes and pressure holes around the circumference make the die head more evenly stressed, further improving the stability of the die head installation.

[0007] Preferably, the rear sidewall of the locking hole is provided with a second inclined surface, the angle of the second inclined surface is set to 45° to 60°, the slider is provided with a first inclined surface, the first inclined surface and the second inclined surface are slidably connected, and the two have the same inclination angle.

[0008] By machining a first inclined surface with an angle of 45° to 60° on the outer side of the upper side of the slider, and simultaneously machining a second inclined surface with the same angle on the rear sidewall of the locking hole, and ensuring a precise sliding fit between the two inclined surfaces, a sloped linkage structure adapted for pressure transmission is constructed. When the extrusion pressure inside the tube increases, the pressure generated by the molten PVC on the inner wall of the tube indirectly acts on the end of the slider located in the pressure hole, pushing the slider upward. Because the first inclined surface of the slider and the second inclined surface of the locking hole are perfectly matched in angle, a guiding force is generated along the slope during the upward movement of the slider, causing the slider to move synchronously towards the front of the locking hole. This movement not only makes the fit between the slider and the rear sidewall of the locking hole tighter, but also, through the sloped fit, allows for... The upward displacement of the slider is cleverly converted into a forward clamping force on the die head mounting section, further reducing the fit gap between the die head and the material tube, significantly strengthening the locking effect of the connection between the die head and the material tube, effectively avoiding the connection loosening problem caused by the die head moving backward under high pressure conditions, and also greatly reducing the risk of molten PVC seeping out from the connection. At the same time, the 45° to 60° tilt angle design can ensure the high efficiency of pressure transmission, ensuring that the slider can respond in time with pressure changes, while also taking into account the stability of the structure itself, avoiding the slider slipping out of control due to excessive angle, and the pressure transmission efficiency being affected by excessively small angle. Ultimately, the slider moves smoothly and remains locked when the pressure changes, thereby improving the fit between the die head and the material tube.

[0009] Preferably, an installation groove is provided on the inner wall of the material tube. The installation groove is coaxial with the material tube and is located on the front side of the material tube. The vertical projection of the pressure hole is located within the vertical projection of the installation groove. An elastic metal sheet is provided in the installation groove. The edge of the elastic metal sheet is welded to the installation groove. The outer wall of the elastic metal sheet is fixedly connected to the lower end of the inner wall of the slider.

[0010] By creating a mounting groove coaxial with and located at the front of the material tube on the inner wall of the tube, it is ensured that the vertical projection of all pressure holes falls within the vertical projection range of the mounting groove. Simultaneously, elastic metal sheets with edges welded and fixed to the mounting groove are arranged within the groove, ensuring the upper end of the elastic metal sheets is in close contact with the lower end of the slider. This constructs a slider locking structure driven primarily by the internal pressure of the material tube. When the extrusion pressure inside the material tube increases, the high pressure directly acts on the elastic metal sheets, causing them to deform towards the outer wall of the material tube. The deformation force of the elastic metal sheets is directly transmitted to the lower end of the slider in contact with them, pushing the slider to slide stably upwards along the pressure holes, ultimately extending the slider. The die head is reliably locked into the corresponding locking hole. The edge welding fixing method makes it difficult for the elastic metal sheet to fall off or shift under the harsh working conditions of high temperature and high pressure in the tube, which significantly improves the long-term stability of the structure. At the same time, the elastic metal sheet is deformed by the internal pressure of the tube to push the slider. There is no need to set an additional elastic component for the slider, which greatly simplifies the overall structural design. The locking action of the slider is linked with the working pressure of the tube. The higher the pressure, the stronger the deformation force of the elastic metal sheet, and the tighter the fit between the slider and the locking hole, which further strengthens the locking effect of the die head connection and effectively prevents the die head from loosening and molten PVC from seeping out from the connection.

[0011] Preferably, the inner wall of the mounting section is provided with a plurality of insertion slots, the width of the insertion slots being the same as the thickness of the slider. Each insertion slot includes an insertion section and a rotating section. The insertion section is coaxially arranged with the mounting section and is circumferentially arranged with the same center as the mounting section. The insertion slot extends from the rear end face of the mounting section into the rotating section, and the insertion section and the rotating section are connected in an L-shape. The end of the rotating section away from the insertion section is connected to a locking hole.

[0012] By setting multiple insertion slots on the inner sidewall of the die head mounting section that precisely match the size of the slider, and designing the insertion slots as an L-shaped structure including an insertion section and a rotating section, the insertion section and the mounting section are coaxial and distributed along the same circumference, extending from the rear end face of the mounting section to the rotating section. The end of the rotating section smoothly connects with the locking hole, thus constructing a two-stage positioning and locking path of axial insertion and circumferential rotation. When installing the die head, the slider on the material tube must first be smoothly slid in along the axial direction of the insertion section, and then the die head is slowly rotated around the central axis of the mounting section, so that the slider gradually moves to the position of the locking hole with the rotating section. Finally, the slider and the locking hole precisely match to achieve reliable locking. This design, on the one hand, utilizes the axial guiding effect of the insertion section to ensure that the slider can be accurately embedded in the groove, effectively preventing damage to the slider due to misalignment during die head installation. At the same time, the L-shaped structure can temporarily limit the die head during rotation, preventing the die head from accidentally falling off during installation. On the other hand, the tight connection between the rotating section and the locking hole provides circumferential positioning constraint when the slider is finally locked into the locking hole, significantly reducing the circumferential displacement of the die head caused by equipment vibration, significantly enhancing the coaxiality and overall stability of the die head after installation. Furthermore, the rotation action can further eliminate the assembly gap between the die head and the material tube, improving the sealing of the connection and preventing molten PVC from seeping out of the gap. In addition, this structure can complete the installation and positioning of the die head without the need for complex tools, ensuring both connection reliability and ease of operation.

[0013] Preferably, the end face of the mounting ring that fits against the inner wall of the front end of the mounting hole is provided with a first conical surface, the taper of the first conical surface being 1:5 to 1:4, and the end face of the inner wall of the front end of the mounting hole is provided with a second conical surface, the taper of the second conical surface being the same as the taper of the first conical surface.

[0014] By machining a first conical surface with a slope of 1:5 to 1:4 on the end face of the mounting ring that fits into the inner wall of the mounting hole, and simultaneously machining a second conical surface with the same slope on the corresponding end face of the inner wall of the mounting hole, a sealing and positioning integrated structure with precise conical surface fitting is constructed. This design, on the one hand, upgrades the traditional planar contact between the mounting ring and the inner wall of the mounting hole to a conical contact by using conical surfaces with the same slope, significantly expanding the effective contact area between the two. Combined with the axial pressure applied during mold head installation, a tight self-tightening seal effect can be formed, effectively preventing molten PVC from seeping out from the gap between the mounting ring and the mounting hole. This reduces waste and raw material waste at the source. On the other hand, the conical structure has natural guiding and centering properties. During the process of fitting the mounting ring into the mounting hole, if the die head has a slight deviation, the conical surface will automatically correct its position through the guidance of the contact surface, ensuring that the die head and the material tube always remain highly coaxial, significantly improving the positioning accuracy of the die head installation. At the same time, the 1:5 to 1:4 slope design will not cause the conical surface to fit loosely or fail to seal due to excessive slope, nor will it cause excessive resistance to fitting the mounting ring or inconvenience due to insufficient slope. Ultimately, while ensuring a stable seal, it further strengthens the coaxiality of the die head and the material tube.

[0015] Preferably, an elastic component is installed in the locking hole. The elastic component includes a fixed plate, a spring, and a moving plate. The fixed plate is fixedly installed at the port of the locking hole away from the slider. A spring is fixedly installed on the side of the fixed plate opposite to the slider. A moving plate is fixedly installed on the other end of the spring. The end face of the moving plate opposite to the spring contacts the upper end face of the slider.

[0016] An elastic assembly consisting of a fixed plate, a spring, and a moving plate is installed inside the locking hole. The fixed plate is fixed to the port of the locking hole away from the slider. The spring is fixed on the side of the fixed plate facing the slider, and the other end of the spring is connected to the moving plate, with the end face of the moving plate facing away from the spring in close contact with the upper end face of the slider. When the equipment is in operation, the extrusion pressure inside the material tube increases, and the elastic metal sheet deforms under high pressure, thus pushing the slider to slide upward along the pressure hole. During the sliding process, the slider compresses the moving plate, causing the spring to compress. At the same time, with the guidance of the inclined surface of the locking hole, the slider moves towards the die head inside the locking hole, achieving stable locking of the die head. When the equipment stops working, the pressure inside the material tube gradually decreases, and the elastic metal sheet loses high-pressure support and rebounds. However, the slider... Lacking its own elasticity, the slider is prone to getting stuck in the locking hole and unable to reset. In this case, the compressed spring releases its stored elasticity, applying a uniform downward pushing force to the slider through the moving plate. This pushes the slider smoothly back to its initial position along the pressure hole, releasing the limiting constraint of the locking hole. This design does not interfere with the normal locking action of the slider during equipment operation, and can actively reset the slider after the machine stops. It eliminates the need to rely on special tools to press the slider, greatly simplifying the operation process of disassembling and assembling the die head. At the same time, the continuous elastic force of the spring can effectively avoid the problem of jamming caused by minor wear or gaps in the slider due to long-term use, ensuring the stability and reliability of the slider reset after long-term use. This further improves the convenience of die head replacement, reduces equipment maintenance costs, and improves overall production efficiency.

[0017] Preferably, both the first inclined surface and the second inclined surface are subjected to surface hardening treatment, with the surface hardness of the first inclined surface hardened to 48-52 HRC and the surface hardness of the second inclined surface hardened to 52-56 HRC.

[0018] By performing surface hardening treatment on both the first inclined surface of the slider and the second inclined surface of the locking hole, and controlling the surface hardness of the first inclined surface to 48-52 HRC and increasing the surface hardness of the second inclined surface to 52-56 HRC, a sloped mating structure with suitable wear resistance is constructed. The surface hardening treatment significantly improves the wear resistance of the two inclined surfaces, reducing surface wear caused by repeated sliding friction between the slider and the inclined surface of the locking hole during long-term use of the equipment, effectively extending the service life of the components, and reducing problems such as increased locking gap and decreased pressure transmission efficiency caused by slope wear. On the other hand, the differential hardness design, with the second inclined surface having a slightly higher hardness than the first inclined surface, gives the inclined surface of the locking hole, as a fixed component, stronger resistance to deformation, while allowing the inclined surface of the slider, as a moving component, to retain a certain degree of toughness while ensuring wear resistance, reducing the possibility of brittle fracture caused by excessive hardness, ensuring that the sloped mating always maintains a precise angle fit, thereby maintaining a stable sliding connection between the slider and the locking hole, ensuring the reliable performance of the inclined guiding and locking functions under high pressure conditions, and reducing the risks of mold head loosening and molten PVC seepage caused by slope wear.

[0019] Preferably, the second conical surface is provided with an elastic groove that is circumferentially arranged coaxially with the mounting section, and an elastic washer is provided in the elastic groove.

[0020] By creating elastic grooves on the second conical surface that are circumferentially distributed coaxially with the installation section, and embedding elastic washers within these grooves, a flexible sealing structure is constructed based on the conical surface mating. The elastic grooves provide precise installation and positioning space for the elastic washers, ensuring they are evenly distributed along the circumference of the second conical surface. This reduces uneven sealing caused by washer displacement. The elastic washers themselves possess elastic deformation capabilities; when the first and second conical surfaces of the installation ring are in contact, the washers are compressed and deformed, tightly filling any tiny gaps that may exist between the two conical surfaces. Simultaneously, they can adapt to temperature changes during pipe operation, maintaining continuous close contact with the conical surfaces, further enhancing the sealing effect and effectively preventing molten PVC from seeping out of the conical surface gaps. Compared to sealing methods that rely solely on the contact of metal conical surfaces, the addition of elastic washers significantly improves sealing reliability, reducing sealing failures caused by conical surface machining errors or long-term wear. Furthermore, the flexible contact of the elastic washers can buffer the impact force during die installation, protecting the conical surface from bumps and damage, and extending the service life of the components.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention utilizes the pressure inside the material tube to drive the deformation of an elastic metal sheet, which in turn pushes a slider to engage with the first and second inclined surfaces. The higher the pressure, the stronger the clamping force of the slider on the die head, creating a linkage effect that increases pressure and strengthens the locking. Furthermore, the inclined surfaces undergo differentiated surface hardening treatment, which significantly improves wear resistance and reduces the increase in locking gap after long-term use. This ensures that the die head does not loosen under high-pressure conditions, achieving dynamic locking and long-term sealing of the die head connection.

[0022] 2. This invention sets an L-shaped insertion groove that matches the slider in the mold head mounting section. During installation, the slider slides in along the axial direction of the insertion section and rotates to align with the locking hole. After stopping the machine, the elastic component in the locking hole, consisting of a fixed plate, a spring, and a moving plate, automatically releases its elastic force. The moving plate applies a uniform pushing force to the slider, pushing it back to its initial position along the pressure hole. The entire process does not require the use of special tools to press the slider, greatly simplifying the disassembly and assembly process and achieving rapid disassembly and assembly of the mold head.

[0023] 3. This invention upgrades planar contact to self-tightening conical contact by setting a tapered surface with a matching taper on the end face of the mounting ring and the mounting hole. This increases the sealing area and improves sealing performance with the help of axial pressure. At the same time, an elastic groove is opened on the second conical surface to embed an elastic washer. The elastic deformation of the washer fills the tiny gaps on the conical surface, adapting to the thermal expansion and contraction of the material pipe during operation. The double sealing structure effectively blocks the leakage of molten PVC, and the elastic washer can buffer the installation impact force, protect the conical surface from damage, and extend the service life of the component. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the extrusion molding equipment for producing PVC plastic pipes according to the present invention; Figure 2 This is a front view of the extrusion molding equipment for producing PVC plastic pipes according to the present invention; Figure 3 This is a schematic diagram of the material tube and die head layout of the present invention; Figure 4 for Figure 3 Sectional view of AA; Figure 5 for Figure 4 Enlarged view at point D; Figure 6 This is a schematic diagram of the mold head and slider layout of the present invention; Figure 7 This is a bottom view of the mold head; Figure 8 for Figure 7 Sectional view of BB; Figure 9 for Figure 7 A sectional view of CC.

[0025] In the diagram: 1. Frame; 2. Material tube; 201. Extrusion screw; 202. Mounting ring; 2021. First conical surface; 203. Pressure hole; 204. Mounting groove; 3. Die head; 301. Forming section; 302. Mounting section; 303. Mounting hole; 304. Second conical surface; 3041. Elastic groove; 305. Locking hole; 3051. Second inclined surface; 4. Slider; 401. First inclined surface; 5. Elastic metal sheet; 6. Insertion groove; 601. Insertion section; 602. Rotating section; 7. Fixed plate; 8. Spring; 9. Moving plate; 10. Elastic washer; 11. Motor; 12. Reducer; 13. Control console; 14. Electric heating jacket; 15. Feed funnel. Detailed Implementation

[0026] Please see Figures 1 to 9 This invention provides an extrusion molding equipment for producing PVC plastic pipes, the technical solution of which is as follows: For details, please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 9An extrusion molding device for producing PVC plastic pipes includes a material pipe 2 fixedly connected to the upper surface of a frame 1. An extrusion screw 201 is coaxially rotatably mounted inside the material pipe 2. An installation ring 202 is coaxially fixedly connected to the outer wall of the front end of the material pipe 2. A die head 3 is coaxially arranged at the front end of the material pipe 2. The die head 3 includes a forming section 301 and an installation section 302, which are coaxially arranged. The forming section 301 is located in front of the installation section 302. An installation hole 303 is provided inside the installation section 302. The inner diameter of the installation hole 303 is larger than the outer diameter of the installation ring 202. The installation ring 202 is coaxially fitted inside the installation hole 303, with its front end face fitting against the inner wall of the front end of the installation hole 303. Multiple locking holes 305 are provided on the outer wall of the mounting section 302. These locking holes 305 penetrate both the inner and outer sides of the mounting section 302 and are evenly distributed around the central axis of the die head 3. Multiple pressure holes 203 are provided on the outer wall of the material tube 2. These pressure holes 203 penetrate both the inner and outer sides of the material tube 2 and are evenly distributed around the central axis of the material tube 2. The locking holes 305 correspond to the pressure holes 203. A slider 4 is slidably connected within each pressure hole 203. One end of the slider 4 extends outside the material tube 2, and the other end is located inside the pressure hole 203. The end of the slider 4 located inside the pressure hole 203 is elastically connected to the material tube 2. The inner wall of the material tube 2... An installation groove 204 is provided on the upper part of the material tube 2. The installation groove 204 is coaxial with the material tube 2 and is located on the front side of the material tube 2. The vertical projection of the pressure hole 203 is located within the vertical projection of the installation groove 204. An elastic metal sheet 5 is provided in the installation groove 204, and its edge is welded to the installation groove 204. Its upper end face contacts the lower end of the slider 4. A first inclined surface 401 is provided on the outer side of the upper side of the slider 4. The angle of the first inclined surface 401 is set to 45° to 60°. A second inclined surface 3051 is provided on the rear side wall of the locking hole 305. The angle of the second inclined surface 3051 is set to 45° to 60°. The first inclined surface 401 and the second inclined surface 3051 are slidably connected. All inclined surfaces 3051 are surface hardened. The surface hardness of the first inclined surface 401 is hardened to 48-52 HRC, and the surface hardness of the second inclined surface 3051 is hardened to 52-56 HRC. When the die head 3 is connected to the material tube 2, the slider 4 extends into the locking hole 305, and the slider 4 is in contact with the rear side wall of the locking hole 305. An elastic component is installed in the locking hole 305. The elastic component includes a fixed plate 7, a spring 8, and a moving plate 9. The fixed plate 7 is fixedly installed at the port of the locking hole 305 away from the slider 4. The spring 8 is fixedly installed on the side of the fixed plate 7 opposite to the slider 4. The moving plate 9 is fixedly installed on the other end of the spring 8. The end face of the moving plate 9 opposite to the spring 8 is in contact with the upper end face of the slider 4.

[0027] See Figure 3 , Figure 4 , Figure 5 , Figure 6, Figure 7 , Figure 8 and Figure 9 The inner wall of the mounting section 302 is provided with multiple insertion slots 6, the size of which is the same as that of the slider 4. Each insertion slot 6 includes an insertion section 601 and a rotating section 602. The insertion section 601 is coaxially arranged with the mounting section 302, and they are arranged in a circle with the same center. The insertion slot 6 extends from the rear end face of the mounting section 302 into the rotating section 602, and the insertion section 601 and the rotating section 602 are connected in an L-shape. The end of the rotating section 602 is connected to... The locking hole 305 is connected, and the end face of the mounting ring 202 that fits against the inner wall of the front end of the mounting hole 303 is provided with a first conical surface 2021. The slope of the first conical surface 2021 is 1:5 to 1:4. The end face of the inner wall of the front end of the mounting hole 303 is provided with a second conical surface 304. The slope of the second conical surface 304 is 1:5 to 1:4. The second conical surface 304 is provided with an elastic groove 3041 that is coaxially and circumferentially arranged with the mounting section 302. An elastic washer 10 is provided in the elastic groove 3041.

[0028] See Figure 1 , Figure 2 , Figure 3 and Figure 4 The device includes a frame 1, a motor 11, a reducer 12, a control console 13, an electric heating jacket 14, and a feed funnel 15. The motor 11 and the reducer 12 are both fixedly installed on the rear side of the upper end face of the frame 1. The output end of the motor 11 is fixedly connected to the input end of the reducer 12. The control console 13 is connected to the side wall of the reducer 12. The output end of the reducer 12 is coaxially fixedly connected to the extrusion screw 201. The extrusion screw 201 is coaxially arranged with the material tube 2 and extends into the material tube 2. The feed funnel 15 is provided at the rear end of the material tube 2. The electric heating jacket 14 is provided starting from the connection point between the lower end of the feed funnel 15 and the material tube 2.

[0029] Working principle: (Reference) Figures 1 to 9When the equipment is running, raw materials are fed into the feed hopper 15. The motor 11 is started by operating the control panel 13, which drives the extrusion screw 201 to rotate. The extrusion screw 201 mixes the raw materials evenly. Combined with the electric heating jacket 14 outside the feed tube 2, the raw materials are molten. When the molten raw materials are pushed to the front end of the feed tube 2, the pressure at the front end of the feed tube 2 increases. The elastic metal sheet 5 is subjected to pressure and deforms outward. The slider 4, which is in contact with the elastic metal sheet 5, will be pushed into the locking hole 305. The upper end of the slider 4 will press against the elastic component, causing the elastic component to accumulate elastic force. The locking hole 305 has a second inclined surface, which cooperates with the first inclined surface 401 of the slider 4. When the slider 4 is pushed into the locking hole 305, it will be offset to the axial side of the locking hole 305. Since the lower end of the slider 4 is also connected to the pressure hole 203, the greater the pressure, the tighter the connection between the die head 3 and the feed tube 2. Differential surface hardening treatment significantly improves wear resistance and reduces wear on the die head 3 and material tube 2 after long-term use, avoiding the problem of increased clearance between the die head 3 and material tube 2 after long-term use. When the equipment stops running, the internal pressure decreases, the elastic metal sheet 5 returns to its original state, the elastic force of the elastic component is released, and the slider 4 is pushed back to the position in contact with the elastic metal sheet 5 by the elastic force. At this time, the die head 3 does not have the clamping force of the slider 4. Disassembly and assembly only require rotating the die head 3 to allow the slider 4 to disengage from the locking hole 305 along the path of the insertion groove 6, thus completing the disassembly of the die head 3. Similarly, during installation, the insertion section 601 in the insertion groove 6 of the die head 3 is aligned with the position of the slider 4. The die head 3 is pushed towards the material tube 2. When the slider 4 enters the rotating section 602 of the insertion groove 6, the die head 3 is rotated to allow the slider 4 to enter the locking hole 305, thus completing the quick installation of the die head 3 and the material tube 2.

[0030] Please refer to Figures 1 to 9 The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.

Claims

1. An extrusion molding device for producing PVC plastic pipes, comprising a frame, a material pipe fixedly connected to the upper end face of the frame, an extrusion screw coaxially rotatably mounted inside the material pipe, an installation ring coaxially fixedly connected to the outer side wall of the front end of the material pipe, a die head coaxially disposed at the front end of the material pipe, the die head comprising a forming section and an installation section, the forming section and the installation section being coaxially disposed, and the forming section being located in front of the installation section, the installation section having an installation hole, the inner diameter of the installation hole being larger than the outer diameter of the installation ring, the installation ring being coaxially sleeved in the installation hole, and the outer side wall of the installation section having multiple locking holes, all of which penetrate through the inner and outer sides of the installation section. Furthermore, multiple locking holes are evenly distributed around the central axis of the die head, and multiple pressure holes are provided on the outer side wall of the material tube. These pressure holes penetrate both the inner and outer sides of the material tube and are evenly distributed around the central axis of the material tube. The multiple locking holes correspond to the multiple pressure holes respectively. A slider is slidably connected in each pressure hole. One end of the slider extends to the outside of the material tube, and the other end is located in the pressure hole. The end of the slider located in the pressure hole is elastically connected to the material tube. When the die head is connected to the material tube, the slider extends into the locking hole and fits against the rear side wall of the locking hole. The front end face of the mounting ring fits against the front inner wall of the mounting hole. The rear side wall of the locking hole is provided with a second inclined surface, the angle of the second inclined surface is set to 45°~60°, the slider is provided with a first inclined surface, the first inclined surface and the second inclined surface are slidably connected, and the two have the same inclination angle. An installation groove is provided on the inner wall of the material tube. The installation groove is coaxial with the material tube and is located on the front side of the material tube. The vertical projection of the pressure hole is located within the vertical projection of the installation groove. An elastic metal sheet is provided in the installation groove. The edge of the elastic metal sheet is welded to the installation groove. The outer wall of the elastic metal sheet is fixedly connected to the lower end of the inner wall of the slider. The inner wall of the mounting section is provided with multiple insertion slots. The width of the insertion slot is the same as the thickness of the slider. The insertion slot includes an insertion section and a rotating section. The insertion section is coaxial with the mounting section and is circumferentially aligned with the mounting section. The insertion slot extends from the rear end face of the mounting section to the rotating section. The insertion section and the rotating section are connected in an L-shape. The end of the rotating section away from the insertion section is connected to the locking hole. An elastic component is installed inside the locking hole. The elastic component includes a fixed plate, a spring, and a moving plate. The fixed plate is fixedly installed at the port of the locking hole away from the slider. A spring is fixedly installed on the side of the fixed plate opposite to the slider. A moving plate is fixedly installed on the other end of the spring. The end face of the moving plate opposite to the spring is in contact with the upper end face of the slider.

2. The extrusion molding equipment for PVC plastic pipe production according to claim 1, characterized in that, The end face of the mounting ring that fits into the inner wall of the front end of the mounting hole is provided with a first conical surface, the taper of which is 1:5 to 1:

4. The end face of the inner wall of the front end of the mounting hole is provided with a second conical surface, the taper of which is the same as that of the first conical surface.

3. The extrusion molding equipment for PVC plastic pipe production according to claim 1, characterized in that, Both the first and second inclined surfaces undergo surface hardening treatment, with the surface hardness of the first inclined surface hardened to 48–52 HRC and the surface hardness of the second inclined surface hardened to 52–56 HRC.

4. The extrusion molding equipment for PVC plastic pipe production according to claim 2, characterized in that, The second conical surface is provided with an elastic groove that is circumferentially aligned with the installation section, and an elastic washer is provided inside the elastic groove.

Images