PVC pipe joint injection molding mold

Abstract

This invention discloses an injection molding die for PVC pipe fittings, belonging to the field of injection molding technology. It includes: a fixed mold base with a first water-cooling plate fixed to one end face; a sliding mold base, parallel to one side of the fixed mold base; a fixed template, installed on the end face of the first water-cooling plate near the sliding mold base; a movable template, fixed to the side of the sliding mold base near the fixed template; two mold cavities, symmetrically arranged in the fixed template; and two core guide units, each installed in one of the mold cavities on the fixed template. In this invention, the fixed template and the movable template can fit tightly together to form two injection molding cavities for the PVC pipe fittings. The core shaft in the main shaft core device can be eccentrically or coaxially distributed with the mold cavity as the shaft rotates, which facilitates rapid filling of the mold with PVC material, shortens the injection cycle, prevents material shortages or incomplete filling due to flow obstruction, and improves product quality.

Description

Technical Field

[0001] This invention belongs to the field of injection mold technology, specifically an injection molding mold for PVC pipe fittings. Background Technology

[0002] PVC pipe fittings (such as elbows and tees) are indispensable connecting components in building drainage, electrical conduit installation, and chemical fluid transportation. Among them, T-shaped tees, with their three-way interface, have a complex structure and are difficult to mold internal flow channels. Most T-shaped tee molds on the market use a single-cavity design. Although the mold structure is relatively simple, only one product can be produced per molding cycle, limiting output per unit time. For mass production needs, this results in high energy consumption and labor costs. While some molds are designed with multiple cavities to produce multiple products at once, the irregular structure of the T-shaped fitting causes uneven resistance distribution of the molten plastic during flow within the cavities. This makes it difficult for the plastic to effectively fill the deep cavities under high pressure, especially in areas far from the gate, leading to material shortages and poor product quality.

[0003] Therefore, it is necessary to provide an injection molding die for PVC pipe fittings to solve the problems mentioned in the background art. Summary of the Invention

[0004] To achieve the above objectives, the present invention provides the following technical solution: a PVC pipe fitting joint injection molding mold, comprising: a fixed mold base, on one side of which a first water-cooling plate is fixed; a sliding mold base, parallel to one side of the fixed mold base; and a fixed template, installed on the end face of the first water-cooling plate near the sliding mold base, wherein the fixed template has multiple positioning holes.

[0005] The movable template is fixed on the side of the sliding mold base near the fixed template. Positioning guide posts are vertically fixed at the four corners of the movable template, and each positioning guide post is slidably assembled with the positioning hole. The main channel is opened in the middle of the sliding mold base. There are two model cavities, which are symmetrically opened in the fixed template. There are two guide core units, which are respectively installed in the model cavities on the fixed template.

[0006] Preferably, a second water-cooling plate is fixed between the movable template and the sliding mold base. Cooling channels are provided in both the first and second water-cooling plates, and guide joints are connected to the outside of each cooling channel. A support plate is slidably arranged inside the first water-cooling plate. An inner spring is connected between the support plate and the fixed template. Multiple ejector pins are vertically fixed on the support plate, and the ejector pins are slidably connected through the fixed template.

[0007] Preferably, a DC channel is provided in the fixed template, and the two ends of the DC channel are respectively connected to two model cavities. A transfer channel is provided in the middle of the DC channel, and the main channel is connected to the DC channel through the transfer channel.

[0008] Preferably, the guide core unit includes a main spindle core device arranged in a vertical direction and a side spindle core device arranged in a horizontal direction, with one end of the side spindle core device slidingly abutting against the side wall of the main spindle core device.

[0009] Preferably, the main spindle core device includes: a main spindle frame, which is vertically fixed on the fixed template; a guide shaft, which is slidably connected inside the main spindle frame, and a first pneumatic telescopic rod is fixed on the main spindle frame, the telescopic end of the first pneumatic telescopic rod being connected to the guide shaft; a sealing shaft, which is coaxially fixed to the lower end face of the guide shaft, and the sealing shaft is in sliding sealing contact with the inner wall of the model cavity; a tube forming shaft, which is coaxially fixed to the lower end face of the sealing shaft; and a mandrel, which is installed at the lower end of the tube forming shaft, and a forming sleeve is concentrically fitted around the mandrel.

[0010] Preferably, the side shaft core device includes: a side shaft frame, which is horizontally fixed to one end face of the fixed template, and an outer ring sleeve is fixed inside the side shaft frame; a sliding shaft, which is slidably connected inside the outer ring sleeve, and a second pneumatic telescopic rod is horizontally fixed on the side shaft frame, one end of the second pneumatic telescopic rod being connected to the sliding shaft; and a coupling, which is coaxially disposed at one end of the sliding shaft, and the end of the coupling has a cut that matches the surface of the molding sleeve.

[0011] Preferably, a fixing tube is eccentrically fixed inside the tube forming shaft, and a rotating shaft is rotatably connected inside the fixing tube via a bearing. The lower end of the rotating shaft is eccentrically fixed to the mandrel.

[0012] The mandrel is rotatably connected inside the molding sleeve.

[0013] Preferably, the upper surface of the molding sleeve is in sealed sliding contact with the lower surface of the tube forming shaft, and the mandrel is eccentrically or coaxially arranged with the mold cavity under the rotation of the rotating shaft; a built-in motor is installed in the guide shaft, and the output end of the built-in motor is connected to the rotating shaft for transmission through gear meshing.

[0014] Preferably, a hinge is slidably connected inside the sliding shaft, one end of the hinge is fixed with a U-shaped guide, and one end of the coupling is rotatably connected to the U-shaped guide via a guide pin; a support spring is connected between the hinge and the sliding shaft; a limit pin is fixed at the center of the cut of the coupling, and a limit hole is opened on the outer wall of the molding sleeve, with the limit pin slidingly engaging with the limit hole.

[0015] Preferably, a magnetic suction shaft is embedded and fixed in the lower side wall of the tube forming shaft, and a positioning shaft is correspondingly provided in the upper side wall of the forming sleeve, and the magnetic suction shaft and the positioning shaft are magnetically attracted to each other.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In the present invention, a fixed template and a movable template are respectively installed on the fixed mold base and the sliding mold base, which can be closely fitted to form two injection molding cavities for PVC pipe fittings. The fixed template has a DC channel, and its two ends are respectively connected to the two mold cavities. In this way, two PVC pipe fittings can be injection molded simultaneously during injection molding production, resulting in high production efficiency. The main spindle core device and the side spindle core device are mainly set to cooperate with each other to form a T-shaped injection mandrel, which can meet the molding requirements of T-shaped tee pipe fittings.

[0017] Furthermore, in this invention, the mandrel in the spindle core device can be eccentrically or coaxially distributed with the mold cavity during the rotation of the shaft. In this way, during the initial injection molding process, when the molding sleeve outside the mandrel is eccentrically distributed with the mold cavity and away from the DC channel, the injection plastic can quickly enter the mold cavity through the DC channel. The injection plastic can enter the deep part of the cavity at a faster speed and lower pressure. Especially for long pipes, this can effectively prevent defects such as insufficient filling or flow marks, which is conducive to the rapid filling of PVC material, shortens the injection cycle, and prevents material shortage or incomplete filling due to flow obstruction. When a certain amount is reached, the molding sleeve outside the mandrel can return to the coaxial state with the mold cavity, ensuring the dimensional accuracy of the product and facilitating subsequent molding. In addition, the mandrel can use the molding sleeve to agitate the injection plastic in the mold cavity during the rotation of the shaft, which helps to disperse the local internal stress formed by excessive cooling. At the same time, it can also promote the discharge of gas in the cavity, thereby reducing product bubbles and warpage deformation, and improving the physical properties and surface quality of the product. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the split structure of the fixed template and the movable template in this invention;

[0020] Figure 3 This is a schematic cross-sectional view of the main spindle core assembly and the side spindle core assembly in this invention. Figure 1 ;

[0021] Figure 4 This is a schematic cross-sectional view of the main spindle core assembly and the side spindle core assembly in this invention. Figure 2 ;

[0022] Figure 5 This is a schematic diagram of the coupling structure in this invention;

[0023] Figure 6This is a schematic diagram of the eccentric distribution structure of the molding sleeve and the mold cavity in this invention;

[0024] In the diagram: 1. Fixed mold base; 11. First water-cooled plate; 12. Fixed template; 13. Positioning hole; 14. Mold cavity; 15. Guide joint; 16. Support plate; 17. Inner spring; 18. DC channel; 19. Transfer channel; 2. Sliding mold base; 21. Second water-cooled plate; 22. Movable template; 23. Positioning guide post; 24. Main channel; 3. Main spindle core device; 31. Main spindle frame; 32. Guide shaft; 33. First pneumatic telescopic rod; 34. Sealing shaft; 35. Pipe forming shaft; 36. Mandrel; 37. Forming sleeve; 38. Magnetic suction shaft; 4. Side shaft core device; 41. Side shaft frame; 42. Sliding shaft; 43. Second pneumatic telescopic rod; 44. Coupling; 45. Joint shaft; 46. U-shaped guide frame; 47. Limiting pin; 48. Limiting hole; 5. Fixed tube; 51. Rotating shaft; 52. Built-in motor. Detailed Implementation

[0025] Please see Figures 1-6 In this embodiment of the invention, a PVC pipe fitting injection molding die includes: a fixed mold base 1, on one side of which a first water-cooling plate 11 is fixed; a sliding mold base 2, parallel to one side of the fixed mold base 1; a fixed template 12, installed on the end face of the first water-cooling plate 11 near the sliding mold base 2, the fixed template 12 having multiple positioning holes 13; and a movable template 22, fixed to the side of the sliding mold base 2 near the fixed template 12, the movable template 22 having positioning guide posts 23 vertically fixed at its four corners, each positioning guide post 23 being slidably assembled with the positioning holes 13; the fixed template 12 and the movable template... 22 can be sealed in contact, and a hydraulic propulsion unit is installed outside the sliding mold base 2, which can horizontally push the sliding mold base 2 closer to or away from the fixed template 12 to realize the mold closing or separation of the injection mold; the main runner 24 is opened in the middle of the sliding mold base 2, and an injection unit is provided outside the sliding mold base 2 for conveying injection plastic into the main runner 24; there are two mold cavities 14, which are symmetrically opened on the left and right sides in the fixed template 12. This arrangement can produce two PVC pipe fittings simultaneously in a single injection molding process, resulting in high injection molding production efficiency; there are two core guide units, which are respectively installed in the mold cavities 14 on the fixed template 12.

[0026] In this embodiment, a second water-cooling plate 21 is fixed between the movable template 22 and the sliding mold base 2. Cooling channels are provided in both the first water-cooling plate 11 and the second water-cooling plate 21, and guide joints 15 are connected to the outside of the cooling channels. A cooling medium conveying system is connected to the outside of the guide joints 15. The cooling medium can be quickly cooled through the cooling channels to facilitate the cooling and molding of the PVC pipe fitting after injection molding. A support plate 16 is slidably arranged in the first water-cooling plate 11. An inner spring 17 is connected between the support plate 16 and the fixed template 12. Multiple ejector pins are vertically fixed on the support plate 16. The ejector pins are slidably connected through the fixed template 12. A lifting cylinder can be provided on the fixed mold base 1 to push the support plate 16 towards one side of the fixed template 12. In this way, after the PVC pipe fitting is injected, the support plate 16 can use the ejector pins to achieve the demolding operation of the PVC pipe fitting.

[0027] In a preferred embodiment, a DC channel 18 is provided in the fixed template 12, and the two ends of the DC channel 18 are respectively connected to the two model cavities 14. A transfer channel 19 is provided in the middle of the DC channel 18, and the main channel 24 is connected to the DC channel 18 through the transfer channel 19. In this way, the injection plastic in the main channel 24 can be pressurized and filled into the two model cavities 14 through the DC channel 18.

[0028] In this embodiment, the guide core unit includes a main spindle core device 3 arranged in the vertical direction and a side spindle core device 4 arranged in the horizontal direction. One end of the side spindle core device 4 slides against the side wall of the main spindle core device 3. The main spindle core of the main spindle core device 3 is responsible for forming the longitudinal main pipe hole, and the side spindle core of the side spindle core device 4 is responsible for forming the transverse branch pipe hole. In this way, the side spindle core device 4 and the main spindle core device 3 are combined to form a T-shaped injection molding mandrel, which can meet the forming requirements of T-shaped tee pipe fittings.

[0029] In this embodiment, the main spindle core device 3 includes: a main spindle frame 31, which is vertically fixed on the fixed template 12; a guide shaft 32, which is slidably connected inside the main spindle frame 31, and a first pneumatic telescopic rod 33 is fixed on the main spindle frame 31. The telescopic end of the first pneumatic telescopic rod 33 is connected to the guide shaft 32, and it can axially push the guide shaft 32 to slide up and down; a sealing shaft 34, which is coaxially fixed to the lower end face of the guide shaft 32. The sealing shaft 34 makes sliding sealing contact with the inner wall of the model cavity 14, and the sealing shaft 34 can seal and block the port of the model cavity 14, thereby making The mold cavity 14 forms a closed injection space to prevent the injection plastic from flowing out; the tube end forming shaft 35 is coaxially fixed to the lower end face of the sealing shaft 34; the mandrel 36 is installed at the lower end of the tube end forming shaft 35, and the mandrel 36 is fitted with a forming sleeve 37. In the injection molding process, the tube end forming shaft 35 can abut against and seal against the bottom wall of the mold cavity 14 under the extension and retraction of the first pneumatic telescopic rod 33. Thus, the tube end forming shaft 35 is mainly used for forming the upper tube end of the PVC pipe fitting, while the forming sleeve 37 on the mandrel 36 is used for forming the pipe body and the lower tube end of the PVC pipe fitting.

[0030] In this embodiment, the side shaft core device 4 includes: a side shaft frame 41, which is horizontally fixed to one side end face of the fixed template 12, and an outer ring sleeve is fixed inside the side shaft frame 41; a sliding shaft 42, which is slidably connected inside the outer ring sleeve, and a second pneumatic telescopic rod 43 is horizontally fixed on the side shaft frame 41, one end of the second pneumatic telescopic rod 43 being connected to the sliding shaft 42, and the sliding shaft 42 being able to make a sealing contact with the side port of the model cavity 14 to prevent the injection plastic from flowing out of the side port; and a coupling 44, which is coaxially arranged on the side shaft frame 12. One end of the sliding shaft 42 and the end of the coupling 44 are provided with a cut that matches the surface of the molding sleeve 37. In this way, during injection molding, the coupling 44 can be tightly structured with the surface of the molding sleeve 37 through the cut at the end, and the two cooperate to form a T-shaped mandrel. In the demolding stage, the second pneumatic telescopic rod 43 can first control the coupling 44 to slide away from the PVC pipe fitting joint under the shrinkage adjustment, and then the first pneumatic telescopic rod 33 controls the molding sleeve 37 to slide away from the PVC pipe fitting joint, so as to realize the rapid demolding operation.

[0031] In a preferred embodiment, a fixing tube 5 is eccentrically fixed inside the tube forming shaft 35, and a rotating shaft 51 is rotatably connected inside the fixing tube 5 via a bearing. The lower end of the rotating shaft 51 is eccentrically fixed to the mandrel 36. The mandrel 36 is rotatably connected inside the forming sleeve 37.

[0032] In this embodiment, the upper surface of the molding sleeve 37 is in sealed sliding contact with the lower surface of the tube forming shaft 35. The mandrel 36 is eccentrically or coaxially arranged with the mold cavity 14 under the rotation of the rotating shaft 51. A built-in motor 52 is installed inside the guide shaft 32. The output end of the built-in motor 52 is connected to the rotating shaft 51 through gear meshing. That is, the built-in motor 52 can drive the rotating shaft 51 to rotate and adjust. In this way, the mandrel 36 below the rotating shaft 51 can be eccentrically or coaxially arranged with the mold cavity 14 during the rotation of the rotating shaft 51. With this arrangement, in the initial injection molding stage, the eccentricity between the mandrel 36 and the mold cavity 14 can be utilized. The distribution of the molding sleeve 37 away from the DC channel 18 on the fixed template 12 expands the space of the inlet and reduces the resistance to plastic flow. The plastic injected into the DC channel 18 can flow quickly into the mold cavity 14. When the plastic is filled to a certain amount, the mandrel 36 can rotate to restore the coaxial state with the mold cavity 14, ensuring that the inner hole and outer wall of the molded PVC pipe fitting are concentric and the wall thickness is uniform, thus ensuring the dimensional accuracy of the product. This effectively solves the problem of uneven resistance distribution when the plastic flows in the cavity due to the irregular structure of the T-shaped pipe fitting in traditional molds, especially in the deep cavity far from the gate, where incomplete filling (material shortage) is likely to occur.

[0033] In this embodiment, a hinge 45 is slidably connected inside the sliding shaft 42. One end of the hinge 45 is fixed with a U-shaped guide 46. One end of the coupling 44 is rotatably connected to the U-shaped guide 46 via a guide pin. A support spring is connected between the hinge 45 and the sliding shaft 42. The support spring can use its elastic force to partially disengage the coupling 44 from the end of the sliding shaft 42, so that the coupling 44 can swing through the U-shaped guide 46. A limit pin 47 is fixed at the center of the cut of the coupling 44, and a limit hole 48 is opened on the outer wall of the molding sleeve 37. The limit pin 47 slides in conjunction with the limit hole 48. Specifically, the limit pin 47 at the cut of the coupling 44 can be pre-inserted into the limit hole 48. At this time, the coupling 44 and the sliding shaft 42 are separated at their ends by the elastic force of the support spring. The mandrel 36 is eccentrically distributed with the mold cavity 14 as the rotating shaft 51 rotates, and then... High-pressure injection molding compound is fed into the mold cavity through DC channel 18. When the injection compound reaches a certain amount (approximately 85% of the total filling volume), the rotating shaft 51 drives the mandrel 36 to rotate at low speed. During the eccentric rotation of the mandrel 36, the molding sleeve 37 extrudes the injection compound within the mold cavity 14. During this process, the coupling 44 can swing accordingly through the U-shaped guide 46, while the cut on the coupling 44 always remains in close contact with the molding sleeve 37. The molding sleeve 37 does not rotate with the mandrel 36, thus achieving the agitation effect on the injection compound. This effectively fills the gaps caused by cooling and shrinkage, preventing product depressions. It also promotes the discharge of gas from the mold cavity, thereby reducing product bubbles and warping deformation, and improving the physical properties and surface quality of the product. Afterward, the mandrel 36 rotates back to a coaxial state with the mold cavity 14, and the second pneumatic telescopic rod 43 horizontally pushes the coupling 44 to tightly engage with the sliding shaft 42, compressing the support spring.

[0034] It should be noted that the lower end of the molding sleeve 37 is always in close contact with the bottom wall of the mold cavity 14, while the upper end of the molding sleeve 37 is in close contact with the lower surface of the molding shaft 35 at the nozzle. This prevents the injection plastic from flowing into the gap in the molding sleeve 37. In addition, a high-temperature resistant rubber ring can be set at the port of the coupling 44. When the ends of the coupling 44 and the sliding shaft 42 are separated, the high-temperature resistant rubber ring is in close contact with the port of the sliding shaft 42, thus preventing the injection plastic from flowing into the coupling 44. Alternatively, the end of the sliding shaft 42 can be designed as an inner conical surface, and the inner wall of the port of the coupling 44 can be designed as a matching outer conical surface. When the coupling 44 and the sliding shaft 42 are in a "separated" state (corresponding to the eccentric position of the mandrel 36), a small gap is maintained between the conical surfaces, which does not affect the rotation and oscillation. A chip removal groove is opened in the sliding shaft 42 to allow a small amount of injection plastic to enter the gap between the coupling 44 and the sliding shaft 42.

[0035] In this embodiment, a magnetic suction shaft 38 is embedded and fixed in the lower side wall of the tube forming shaft 35, and a positioning shaft is correspondingly provided in the upper side wall of the forming sleeve 37. The magnetic suction shaft 38 and the positioning shaft are magnetically attracted to each other. Thus, when the mandrel 36 rotates back to be coaxial with the tube forming shaft 35, the forming sleeve 37 can be positioned with the tube forming shaft 35 under the magnetic attraction of the magnetic suction shaft 38 and the positioning shaft, thereby ensuring that the limiting hole 48 on the forming sleeve 37 is always aligned with the limiting pin 47 of the coupling 44, which facilitates the insertion and positioning of the two.

[0036] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A PVC pipe fitting joint injection molding mold characterized by, It includes: A fixed mold base (1) has a first water-cooling plate (11) fixed on one end face of its side. The sliding mold base (2) is arranged parallel to one side of the fixed mold base (1); A fixed template (12) is installed on the end face of the first water-cooled plate (11) near the sliding mold base (2), and the fixed template (12) is provided with multiple positioning holes (13). The movable template (22) is fixed on the side of the sliding mold base (2) close to the fixed template (12). The four corners of the movable template (22) are respectively vertically fixed with positioning guide posts (23), and each positioning guide post (23) is slidably assembled with the positioning hole (13). The main channel (24) is located in the middle of the sliding mold base (2); Two model cavities (14) are provided and are symmetrically opened in the fixed template (12); The core guide unit is configured as two and is installed in each model cavity (14) on the fixed template (12).

2. The PVC pipe fitting joint injection molding mold according to claim 1, characterized in that: A second water-cooling plate (21) is fixed between the movable template (22) and the sliding mold base (2). Cooling channels are provided in both the first water-cooling plate (11) and the second water-cooling plate (21), and guide joints (15) are connected to the outside of the cooling channels. A support plate (16) is slidably disposed inside the first water-cooled plate (11). An inner spring (17) is connected between the support plate (16) and the fixed template (12). Multiple ejector pins are vertically fixed on the support plate (16), and the ejector pins are slidably connected through the fixed template (12).

3. The PVC pipe fitting joint injection molding mold according to claim 1, characterized in that: The fixed template (12) has a DC channel (18) inside. The two ends of the DC channel (18) are connected to the two model cavities (14) respectively. The middle part of the DC channel (18) has a transfer channel (19). The main channel (24) is connected to the DC channel (18) through the transfer channel (19).

4. The PVC pipe fitting joint injection molding mold of claim 1, wherein: The guide core unit includes a main spindle core device (3) arranged in the vertical direction and a side spindle core device (4) arranged in the horizontal direction. One end of the side spindle core device (4) slides against the side wall of the main spindle core device (3).

5. The PVC pipe fitting joint injection molding mold according to claim 4, characterized in that, The spindle core assembly (3) includes: The main shaft bracket (31) is vertically fixed on the fixed template (12); A guide shaft (32) is slidably connected inside the main shaft frame (31). A first pneumatic telescopic rod (33) is fixed on the main shaft frame (31). The telescopic end of the first pneumatic telescopic rod (33) is connected to the guide shaft (32). A sealing shaft (34) is coaxially fixed to the lower end face of the guide shaft (32), and the sealing shaft (34) slides and seals against the inner wall of the model cavity (14). The nozzle forming shaft (35) is coaxially fixed to the lower end face of the sealing shaft (34); A mandrel (36) is installed at the lower end of the tube forming shaft (35), and a forming sleeve (37) is fitted around the mandrel (36) in a concentric circle.

6. The PVC pipe fitting joint injection molding mold according to claim 5, wherein, The side shaft core device (4) includes: A side shaft bracket (41) is horizontally fixed to one side end face of the fixed template (12), and an outer ring is fixed inside the side shaft bracket (41); A sliding shaft (42) is slidably connected inside the outer ring sleeve. A second pneumatic telescopic rod (43) is horizontally fixed on the side shaft bracket (41). One end of the second pneumatic telescopic rod (43) is connected to the sliding shaft (42). The coupling (44) is coaxially disposed at one end of the sliding shaft (42), and the end of the coupling (44) has a cut that matches the surface of the molding sleeve (37).

7. The PVC pipe fitting joint injection molding mold according to claim 6, characterized in that: A fixing tube (5) is eccentrically fixed inside the forming shaft (35). A rotating shaft (51) is rotatably connected inside the fixing tube (5) via a bearing. The lower end of the rotating shaft (51) is eccentrically fixed to the mandrel (36). The mandrel (36) is rotatably connected inside the molding sleeve (37).

8. The PVC pipe fitting joint injection molding mold according to claim 7, characterized in that: The upper surface of the molding sleeve (37) is in sealed sliding contact with the lower surface of the tube forming shaft (35), and the mandrel (36) is eccentrically or coaxially arranged with the mold cavity (14) under the rotation of the rotating shaft (51). The guide shaft (32) is equipped with a built-in motor (52), and the output end of the built-in motor (52) is connected to the rotating shaft (51) for transmission through gear meshing.

9. The PVC pipe fitting joint injection molding mold of claim 7, wherein: The sliding shaft (42) is slidably connected to a joint shaft (45), one end of which is fixed with a U-shaped guide frame (46), and one end of the coupling (44) is rotatably connected to the U-shaped guide frame (46) through a guide pin; A support spring is connected between the joint shaft (45) and the sliding shaft (42); A limiting pin (47) is fixed at the center of the cut of the coupling (44), and a limiting hole (48) is opened on the outer wall of the molding sleeve (37). The limiting pin (47) and the limiting hole (48) slide together.

10. The PVC pipe fitting joint injection molding mold of claim 7, wherein: A magnetic suction shaft (38) is embedded and fixed in the lower side wall of the forming shaft (35), and a positioning shaft is correspondingly provided in the upper side wall of the forming sleeve (37). The magnetic suction shaft (38) and the positioning shaft are magnetically attracted to each other.

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