A two-color molding die and injection molding method for a double-end flared tube

Abstract

The present application relates to a kind of double-color forming mould and injection molding method of double-end flared tube, including die and punch, die includes movable die and fixed die, punch includes left punch group and right punch group, by being respectively set up with first cavity communication first glue injection port, second glue injection port being communicated with second cavity on movable die, and using anti-blocking rod to prevent second glue injection port, make first cavity glue injection still keep the communication of second glue injection port and second cavity, realize first injection molding outer layer of double-end flared tube, after injection molding inner layer also can keep all water port is located in double-end flared tube outside, eliminate the technical problems that water port influences inner layer injection after inner layer injection, and eliminate the technical problems that water port is difficult to remove after inner layer injection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of plastic forming or connecting, and particularly relates to a double-color forming mold and injection molding method for a double-head flared pipe. BACKGROUND

[0002] Currently, a common double-color injection mold for first outer layer and then inner layer usually sets an injection port on a punch or a core, such as the injection syringe piston and its manufacturing method and device disclosed in Chinese patent CN 108721737 A. This structure can cool the outer layer through the water channel in the cavity, but if the inner layer is cooled by relying on the cavity, the cooling effect will be reduced due to the blockage of the outer layer, resulting in a decrease in the cooling speed and the efficiency of injection molding. Meanwhile, when the outer layer is injected, the solidified glue of the injection port remaining on the inner wall of the outer layer will form burrs or protrusions (usually referred to as “water ports”), which will affect the injection of the inner layer. When the inner layer is injected, the solidified glue of the injection port remaining on the inner wall of the inner layer also needs to be removed through secondary processing. However, the burrs or protrusions on the inner wall of the inner layer are difficult to remove due to the narrow operation space, and therefore, it is necessary to improve the injection structure of the double-color injection mold for first outer layer and then inner layer to overcome the above technical problems. SUMMARY

[0003] The technical problem to be solved by the application is to provide a double-color forming mold for a double-head flared pipe, which solves the technical problems of burrs or protrusions on the inner wall of the outer layer affecting the injection of the inner layer and the inconvenience of removing the burrs or protrusions on the inner wall of the inner layer.

[0004] To solve the above technical problems, the application adopts the technical scheme of a double-color forming mold for a double-head flared pipe, which comprises a cavity and a punch. The cavity comprises an upper and lower movable mold and a fixed mold. The movable mold is located directly above the fixed mold. The fixed mold and the movable mold are respectively provided with a half cavity on the opposite surfaces. When the movable mold and the fixed mold are closed, a complete double-head flared cavity is formed. The punch comprises a left punch module and a right punch module arranged on the left and right sides of the cavity and respectively opposite to the two ends of the flared cavity. The left punch module comprises a first left punch and a second left punch. The right punch module comprises a first right punch and a second right punch. The first left punch and the first right punch are inserted into the cavity to form a first cavity for injection molding of the outer layer of the double-head flared pipe. The second left punch and the second right punch are inserted into the cavity to form a second cavity between the outer layer of the double-head flared pipe and the inner wall of the outer layer for injection molding of the inner layer of the double-head flared pipe.

[0005] The fixed mold is fixedly arranged. The movable mold is movably connected to a support and driven by a main driver to ascend and descend to realize mold closing and mold opening.

[0006] The left and right core modules are driven by the sub-drivers to perform the operations of closing and opening, and are driven by the conversion drivers to switch the first and second left cores and the first and second right cores;

[0007] The movable mold is provided with a first glue injection opening communicated with the first cavity and a second glue injection opening communicated with the second cavity.

[0008] As a preferred solution, the left core module further comprises a central shaft, the first and second left cores are arranged at a 90° angle and connected to the outer wall of the central shaft perpendicularly, the central shaft is perpendicular to the axis of the cavity, the two ends of the central shaft are rotatably connected to the shaft seats through bearings, the conversion driver is a motor, and the conversion driver is in transmission connection with one end of the central shaft to drive the central shaft to perform a 90° reciprocating swing action.

[0009] The shaft seats at the two ends of the central shaft are slidably connected to the two guide rails through sliding pairs, the extension direction of the guide rails is parallel to the axis of the cavity, the sub-driver is a linear motor or a piston cylinder, and the sub-driver drives the shaft seats at the two ends of the central shaft to slide synchronously.

[0010] The right core module and the left core module are mirror-symmetric in structure, have the same driving structure, and are opposite in driving direction.

[0011] As a preferred solution, any central shaft is provided with a main cooling water channel in the axial direction, the second left core and the second right core are respectively provided with cooling branches communicated with the main cooling water channel, and the main cooling water channel forms a water inlet and a water outlet at one end of the central shaft for connecting a water inlet pipe and a water return pipe.

[0012] As a preferred solution, the first left core and the first right core are also provided with cooling branches communicated with the main cooling water channel.

[0013] Or the movable mold and the fixed mold are provided with an outer cooling water channel for cooling the outer layer of the double-end expanded pipe.

[0014] As a preferred solution, the anti-blocking driver is a piston cylinder or an electric push rod, the anti-blocking driver is rotationally connected to the support, a large gear is fixedly connected to the shell of the anti-blocking driver, an adjusting motor is connected to one side of the support of the anti-blocking driver, a small gear meshing with the large gear is connected to the output shaft of the adjusting motor, and the adjusting motor drives the anti-blocking driver to reciprocatingly rotate within a certain angle range through gear transmission; the anti-blocking driver is offset to one side of the second glue injection opening, the anti-blocking rod is Z-shaped, one end of the anti-blocking rod is connected to the output shaft of the anti-blocking driver, the other end of the anti-blocking rod swings with the rotation of the anti-blocking driver, and one end of the swing arc path is opposite to the second glue injection opening.

[0015] As a preferred solution, the outer diameter of the anti-blocking rod is smaller than the inner diameter of the second glue injection opening, and an annular exhaust port is formed between the anti-blocking rod and the second glue injection opening; the upper surface of the second left core pin and / or the second right core pin is provided with an exhaust port in communication with the upper edge of the end of the second cavity.

[0016] As a preferred solution, the outer circumferential surface of the first left core pin and the first right core pin is provided with recessed lines, and the depth of the lines satisfies that the inner wall of the outer layer is completely separated from the first left core pin and the first right core pin when the outer layer is cold shrunk.

[0017] As a preferred solution, the opposite ends of the first left core pin and the first right core pin are respectively provided with a male head and a female port matched with each other, the first left core pin and the first right core pin are positioned by the male head and the female port when they are simultaneously inserted into the core cavity, and the annular end face around the male head and the female port is tightly attached; the mating structure of the second left core pin and the second right core pin is the same as that of the first left core pin and the first right core pin.

[0018] The technical problem to be solved by the present application is to provide a double-color forming injection molding method for a double-head flared pipe, and to solve the technical problems of the influence of the outer layer nozzle on the inner layer injection molding and the inconvenience of cleaning the inner layer nozzle when the outer layer is injected first and then the inner layer is injected.

[0019] To solve the above technical problems, the technical scheme adopted by the present application is as follows: an injection molding method for a double-head flared pipe, using the above-mentioned double-color forming mold, and injecting by the following specific steps:

[0020] a. First, the fixed mold and the movable mold are closed, and then the first left core pin and the first right core pin are closed to form a first cavity, the anti-blocking rod is inserted into the second glue injection opening and abuts against the first left core pin or the first right core pin, the first cavity is injected through the first glue injection opening, and then the first cavity is cooled to form the outer layer of the double-head flared pipe;

[0021] b. pulling out the first left and right punch, withdrawing the anti-blocking rod, switching the second left and right punch to insert into the cavity, the second left and right punch and the outer layer forming the second cavity, injecting the second cavity through the second injection port, then cooling the second cavity to form the inner layer of the double-head flared tube;

[0022] c. pulling out the second left and right punch, lifting the movable die to passively insert the anti-blocking rod into the second injection port and push the double-head flared tube out of the movable die to fall off;

[0023] d. removing the double-head flared tube, repeating steps a-c.

[0024] As a preferred solution, when step b is implemented, the anti-blocking rod is controlled to rotate a certain angle after withdrawing the anti-blocking rod to offset the lower end of the anti-blocking rod from the second injection port to clear the injection space; when step c is implemented, the anti-blocking rod is controlled to reset to push the double-head flared tube to achieve automatic demolding.

[0025] The beneficial effects of the present application are: the present application opens the first injection port communicated with the first cavity and the second injection port communicated with the second cavity on the movable die respectively, and uses the anti-blocking rod to prevent the second injection port from being blocked, so that the second injection port remains connected with the second cavity after the first cavity is injected, realizing that the outer layer of the double-head flared tube is injected first, and the inner layer is injected later, and all the injection ports are located outside the double-head flared tube, eliminating the technical problems that the injection port after the inner layer injection affects the inner layer injection, and the injection port after the inner layer injection is difficult to clean. At the same time, the anti-blocking rod can also be used as an ejector rod during demolding, simplifying the mold structure. BRIEF DESCRIPTION OF DRAWINGS

[0026] The specific embodiments of the present application will be further described in detail below with reference to the accompanying drawings, in which:

[0027] Figure 1 is a structural schematic diagram of the double-color forming mold described in the present application;

[0028] Figure 2 is a schematic diagram of the center shaft end connection structure described in the present application;

[0029] Figure 3 is Figure 1 is an enlarged view of A part in

[0030] Figure 4 is a swing range schematic diagram of the anti-blocking rod described in the present application;

[0031] Figure 5 is a schematic diagram of the second left punch described in the present application;

[0032] Figure 6 is a schematic diagram of the first left punch described in the present application;

[0033] Figure 7 is the state diagram when the inner layer of the double-color forming mold of the present application is injection molded;

[0034] Figures 1-7 In the figure: 1, movable mold; 2, fixed mold; 3, concave mold cavity; 4, left male mold set; 401, first left male mold; 402, second left male mold; 5, right male mold set; 501, first right male mold; 502, second right male mold; 6, first cavity; 7, second cavity; 8, support; 9, main drive; 10, auxiliary drive; 11, conversion drive; 12, first glue injection port; 13, second glue injection port; 14, exhaust port; 15, anti-blocking rod; 16, anti-blocking drive; 17, central shaft; 18, shaft seat; 19, main cooling waterway; 20, cooling branch; 21, water inlet; 22, water outlet; 23, outer layer cooling waterway; 24, large gear; 25, adjusting motor; 26, small gear; 27, texture; 28, male head; 29, female port; 30, annular end face; 31, outer layer; 32, inner layer; guide rail. DETAILED DESCRIPTION

[0035] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0036] As Figures 1-7 shown in the figure, a double-head flared pipe double-color forming mold includes a concave mold and a male mold, wherein the concave mold includes a movable mold 1 and a fixed mold 2 facing each other, the movable mold 1 is located directly above the fixed mold 2, the fixed mold 2 and the movable mold 1 are respectively provided with a half concave mold cavity on the facing surface, and the movable mold 1 and the fixed mold 2 form a complete double-head flared concave mold cavity 3 when they are closed, the male mold includes a left male mold set 4 and a right male mold set 5 respectively arranged on the left and right sides of the concave mold and respectively facing the two ends of the flared pipe of the concave mold cavity 3, the left male mold set 4 includes a first left male mold 401 and a second left male mold 402, the right male mold set 5 includes a first right male mold 501 and a second right male mold 502, the first left male mold 401 and the first right male mold 501 are inserted into the concave mold cavity 3 at the same time to form a first cavity 6, the first cavity 6 is used for injection molding the outer layer of the double-head flared pipe, and the second left male mold 402 and the second right male mold 502 are inserted into the concave mold cavity 3 between the inner wall of the outer layer of the double-head flared pipe at the same time to form a second cavity 7, the second cavity 7 is used for injection molding the inner layer of the double-head flared pipe.

[0037] The double-head flared pipe of the present application has a double-layer structure, the outer layer is a hard rubber layer, and the inner layer is a soft rubber layer.

[0038] The fixed mold 2 is fixedly arranged, the movable mold 1 is movably connected to a support 8 and is driven by a main drive 9 to ascend and descend to realize mold closing and mold opening.

[0039] The left and right punch groups 4 and 5 are driven by the sub-drivers 10 to perform the mold closing and mold opening, and are driven by the conversion driver 11 to switch the first and second left punches 401 and 402 and the first and second right punches 501 and 502.

[0040] The movable mold 1 is provided with a first glue injection port 12 communicated with the first cavity 6 and a second glue injection port 13 communicated with the second cavity 7. An anti-blocking rod 15 is arranged above the movable mold 1 and can be inserted into the second glue injection port 13. When the anti-blocking rod 15 is inserted into the second glue injection port 13, the lower end of the anti-blocking rod 15 is in contact with the surface of the second left punch 402 or the second right punch 502. The support 8 is connected with an anti-blocking driver 16 for driving the anti-blocking rod 15 to move up and down.

[0041] In order to show the internal structure of the die cavity 3, Figure 1 The first left punch 401 is pulled out of the die cavity 3. In the actual injection process, the first left punch 401 and the first right punch 501 are inserted into the die cavity 3 together, which is similar to Figure 7 the state shown.

[0042] The left punch group 4 further comprises a central shaft 17. The first left punch 401 and the second left punch 402 are arranged in a 90° offset angle and are connected to the outer wall of the central shaft 17 perpendicularly. The central shaft 17 is perpendicular to the axial direction of the die cavity 3. The two ends of the central shaft 17 are rotatably connected to the shaft seats 18 through bearings. The conversion driver 11 is a motor. The conversion driver 11 is drivingly connected to one end of the central shaft 17 to drive the central shaft 17 to perform a 90° reciprocating swing. In order to ensure the accuracy of the swing angle, a servo motor or a stepping motor can be used as the conversion driver 11. A limiting device can also be arranged to limit the reciprocating swing of the central shaft 17 within a 90° range. The arrangement of the limiting device is a conventional technical means, which will not be described here.

[0043] In combination with Figure 2 , the shaft seats 18 at the two ends of the central shaft 17 are slidingly connected to the two guide rails 33 through sliding pairs. The extension direction of the guide rails 33 is parallel to the axial direction of the die cavity 3. The sub-driver 10 is a linear motor or a piston cylinder. The sub-driver 10 drives the shaft seats 18 at the two ends of the central shaft 17 to slide synchronously. In the embodiment, the right punch group 5 and the left punch group 4 are mirror-symmetrically arranged and have the same driving structure but opposite driving directions. The left punch group 4 and the right punch group 5 are respectively provided with two sub-drivers 10. Each shaft seat 18 is connected to one sub-driver 10 in a one-to-one manner. The four sub-drivers 10 are controlled by the same controller to perform synchronous actions.

[0044] In practical applications, there are many ways to drive the central shaft 17 to move, such as respectively using electric push rods driven by servo motors to drive the shaft seats 18 at both ends of the central shaft 17, and using the high-precision controllability of the rotation angle of the servo motor to realize the synchronous movement of the central shaft 17 at both ends. Also, a screw nut mechanism can be used to drive the two shaft seats 18 to move, and at the same time, through bevel gears and transmission shafts, the two screws are kept synchronous, and a single motor is used to drive the two screws to rotate synchronously, thereby driving the shaft seats 18 at both ends of the central shaft 17 to move synchronously.

[0045] In this embodiment, the main cooling water path 19 is axially provided in any central shaft 17, and the second left punch 402 and the second right punch 502 are respectively provided with a cooling branch 20 in communication with the main cooling water path 19. The main cooling water path 19 forms a water inlet 21 and a water outlet 22 at one end of the central shaft 17 for connecting the water inlet pipe and the water return pipe. The cooling water enters the main cooling water path 19 from the water inlet 21, then enters the cooling branch 20 respectively, cools the second left punch 402 and the second right punch 502 through the cooling branch 20, cools the inner layer of the double-end expanded tube, and then the cooling water returns to the main cooling water path 19 and flows out for recycling. The main cooling water path 19 is actually composed of two parallel long holes, and each cooling branch 20 is a continuous detour channel. The two ends of the cooling branch 20 are connected to the two long holes of the main cooling water path 19, so that the second left punch 402 and the second right punch 502 can be water-cooled.

[0046] The cooling of the outer layer of the double-end expanded tube can be performed by setting a cooling branch 20 in communication with the main cooling water path 19 inside the first left punch 401 and the first right punch 501, or by setting an outer layer cooling water path 23 inside the movable die 1 and the fixed die 2, Figure 1 Although the first left punch 401 and the first right punch 501 are shown as being provided with cooling branches 20 inside, and the movable die 1 and the fixed die 2 are both provided with outer layer cooling water paths 23, in practical applications, only one of the two can be used.

[0047] The specific layout mode of the outer layer cooling water path 23 can be adjusted according to cooling needs. Water cooling is a conventional technical means for mold cooling, so the specific cooling water path and the connection with the water source are not described in detail in this embodiment.

[0048] In combination with Figure 1 , Figure 3 and Figure 4As shown, the anti-blocking driver 16 is a piston cylinder or an electric push rod, the anti-blocking driver 16 is rotationally connected on the bracket 8, a large gear 24 is fixedly connected on the shell of the anti-blocking driver 16, an adjusting motor 25 is connected on the bracket 8 at one side of the anti-blocking driver 16, a small gear 26 meshing with the large gear 24 is connected on the output shaft of the adjusting motor 25, the adjusting motor 25 drives the anti-blocking driver 16 to reciprocating rotate within a certain angle range such as 90° through gear transmission; the anti-blocking driver 16 is biased at one side of the second glue injection port 13, the anti-blocking rod 15 is in Z-shaped structure, each adjacent bending part of the anti-blocking rod 15 is perpendicular to each other, one end of the anti-blocking rod 15 is connected on the output shaft of the anti-blocking driver 16, the other end swings with the rotation of the anti-blocking driver 16, and the arc path of the swing is opposite to the second glue injection port 13 at one end. The adjusting motor 25 drives the anti-blocking driver 16 to rotate, drives the lower end of the anti-blocking rod 15 to rotate away from the second glue injection port 13, and can clear the glue injection space for the glue injection head to be inserted into the second glue injection port 13 to inject glue.

[0049] As shown in the drawings, Figure 5 The outer diameter of the anti-blocking rod 15 is preferably set to be smaller than the inner diameter of the second glue injection port 13 in the embodiment, and the annular exhaust port 14 is formed between the anti-blocking rod 15 and the second glue injection port 13 to omit the exhaust port 14 additionally arranged in communication with the first glue injection port 12, and correspondingly, the position of the second glue injection port 13 is arranged at the upper edge of the second cavity 7; the upper surface of the second left core pin 402 is provided with the exhaust port 14 in communication with the upper edge of the end of the second cavity 7, and in actual application, the exhaust port 14 in communication with the second cavity 7 can be arranged at other positions according to needs, such as the upper surface of the second right core pin 502.

[0050] As shown in the drawings, Figure 6 The outer circumferential surface of the first left core pin 401 and the first right core pin 501 is also provided with the recessed texture 27, and the depth of the texture 27 satisfies that the inner wall of the outer layer completely separates from the first left core pin 401 and the first right core pin 501 when the outer layer is cold contracted. The texture 27 makes the inner wall of the outer layer also form a convex texture, and when the inner layer is injection molded, the inner layer and the outer layer improve the bonding force through the convex texture, so that the inner layer and the outer layer are more firmly combined.

[0051] The opposite ends of the first left core pin 401 and the first right core pin 501 are respectively provided with the male head 28 and the female port 29 matched with each other, and when the first left core pin 401 and the first right core pin 501 are simultaneously inserted into the cavity 3, the male head 28 and the female port 29 are inserted and positioned to improve the concentricity of the two, and the annular end face 30 around the male head 28 and the female port 29 is tightly fitted; the matching structure of the second left core pin 402 and the second right core pin 502 is the same as that of the first left core pin 401 and the first right core pin 501.

[0052] The working process of this invention is a method for injection molding a double-ended flared tube: using the above-mentioned two-color molding die, injection molding is performed through the following specific steps:

[0053] a. First, the fixed mold 2 and the movable mold 1 are closed. Then, the first left punch 401 and the first right punch 501 are closed to form the first cavity 6. The anti-blocking rod 15 is inserted into the second injection port 13 and abuts against the first left punch 401 or the first right punch 501. Glue is injected into the first cavity 6 through the first injection port 12. Then, the first cavity 6 is cooled to form the outer layer 31 of the double-ended flared tube. Figure 1 As shown in the right half.

[0054] b. Pull out the first left punch 401 and the first right punch 501, remove the anti-blocking rod 15, and switch to insert the second left punch 402 and the second right punch 502 into the die cavity 3. The second left punch 402, the second right punch 502, and the outer layer 31 constitute the second cavity 7. Glue is injected into the second cavity 7 through the second injection port 13, and then the second cavity 7 is cooled to form the inner layer 32 of the double-ended flared tube. Figure 7 As shown.

[0055] c. Pull out the second left punch 402 and the second right punch 502, lift the movable mold 1 so that the anti-blocking rod 15 is passively inserted into the second injection port 13 and pushes the double-headed flared tube to disengage from the movable mold 1 and fall off.

[0056] d. Remove the double-ended flared tube and repeat steps a to c.

[0057] When performing step b, after the anti-blocking rod 15 is withdrawn, the anti-blocking rod 15 is rotated at a certain angle so that the lower end of the anti-blocking rod 15 is deviated from the second injection port 13, making room for injection. When performing step c, the anti-blocking rod 15 is reset and used to push the double-ended flared tube to achieve automatic demolding.

[0058] When implementing step a, the outer cooling water channel 23 is used to cool the outer layer 31. During cooling, the outer layer 31 gradually cools from the outer wall to the inner wall. When the inner wall temperature cools down to the demolding temperature, the first left punch 401 and the first right punch 501 immediately disengage and are inserted into the second left punch 402 and the second right punch 502 to inject glue into the second cavity 7. During the injection of glue, since the inner wall of the outer layer still has a certain temperature, it will melt after contacting the inner layer glue due to the temperature of the inner layer glue, so that the outer layer 31 and the inner layer 32 form a fusion effect on the bonding surface, thereby improving the bonding force between the outer layer 31 and the inner layer 32.

[0059] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some examples of its application, and are not intended to limit the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements are all within the scope of protection of the present invention.

Claims

1. A two-color molding die for a double-ended flared tube, comprising a concave die and a convex die, characterized in that, The die includes a movable die (1) and a fixed die (2) facing each other vertically. The movable die (1) is located directly above the fixed die (2). Half of the die cavity is provided on the facing surfaces of the fixed die (2) and the movable die (1). When the movable die (1) and the fixed die (2) are engaged, a complete double-headed flared die cavity (3) is formed. The punch includes a left punch group (4) and a right punch group (5) respectively located on the left and right sides of the die and facing the flared ends of the die cavity (3). The left punch group (4) includes a first left punch (401) and a second left punch (401). The left punch (402) and the right punch group (5) include a first right punch (501) and a second right punch (502). The first left punch (401) and the first right punch (501) are simultaneously inserted into the cavity (3) to form a first cavity (6). The first cavity (6) is used to inject the outer layer of the double-ended flared tube. The second left punch (402) and the second right punch (502) are simultaneously inserted into the cavity (3) and the inner wall of the outer layer of the double-ended flared tube to form a second cavity (7). The second cavity (7) is used to inject the inner layer of the double-ended flared tube. The fixed mold (2) is fixedly set, and the movable mold (1) is movably connected to a bracket (8) and driven by the main driver (9) to rise and fall to realize mold closing and mold opening; The left punch group (4) and the right punch group (5) are driven by the auxiliary driver (10) to perform mold closing and mold opening, and are driven by the conversion driver (11) to switch between the first left punch (401) and the second left punch (402), the first right punch (501) and the second right punch (502). The movable mold (1) is provided with a first injection port (12) communicating with the first cavity (6) and a second injection port (13) communicating with the second cavity (7). An anti-blocking rod (15) that can be inserted into the second injection port (13) is provided above the movable mold (1). When the anti-blocking rod (15) is inserted into the second injection port (13), its lower end is in contact with the surface of the second left punch (402) or the second right punch (502). An anti-blocking driver (16) that drives the anti-blocking rod (15) to rise and fall is connected to the bracket (8).

2. The two-color molding die according to claim 1, characterized in that, The left punch assembly (4) also includes a central shaft (17). The first left punch (401) and the second left punch (402) are arranged circumferentially at a 90° angle and vertically connected to the outer wall of the central shaft (17). The central shaft (17) is perpendicular to the axial direction of the die cavity (3). The two ends of the central shaft (17) are rotatably connected to the bearing seat (18) through bearings. The conversion driver (11) is a motor. The conversion driver (11) is connected to one end of the central shaft (17) and drives the central shaft (17) to perform a 90° reciprocating swing action. The bearing seats (18) at both ends of the central shaft (17) are slidably connected to two guide rails (33) through sliding pairs. The extension direction of the guide rails (33) is parallel to the axial direction of the die cavity (3). The auxiliary driver (10) is a linear motor or a piston cylinder. The auxiliary driver (10) drives the bearing seats (18) at both ends of the central shaft (17) to slide synchronously. The right convex module (5) and the left convex module (4) are mirror symmetrical in structure, have the same driving structure, and drive in opposite directions.

3. The two-color molding die according to claim 2, characterized in that, A main cooling water passage (19) is provided axially on any central shaft (17). Cooling branch passages (20) connected to the main cooling water passage (19) are respectively provided inside the second left punch (402) and the second right punch (502). The main cooling water passage (19) forms an inlet (21) and an outlet (22) at one end of the central shaft (17) to connect the inlet pipe and the return pipe.

4. The two-color molding die according to claim 3, characterized in that, The first left punch (401) and the first right punch (501) are also provided with cooling branch lines (20) that are connected to the main cooling water channel (19). The movable mold (1) and the fixed mold (2) are provided with an outer cooling water channel (23) for cooling the outer layer of the double-ended flared pipe.

5. The two-color molding die according to claim 1, characterized in that, The anti-blocking actuator (16) is a piston cylinder or an electric push rod. The anti-blocking actuator (16) is rotatably connected to the bracket (8). A large gear (24) is fixedly connected to the outer shell of the anti-blocking actuator (16). An adjusting motor (25) is connected to the bracket (8) on one side of the anti-blocking actuator (16). A small gear (26) that meshes with the large gear (24) is connected to the output shaft of the adjusting motor (25). The adjusting motor (25) drives the anti-blocking actuator (16) to reciprocate within a certain angle range through gear transmission. The anti-blocking actuator (16) is biased to one side of the second glue injection port (13). The anti-blocking rod (15) is Z-shaped. One end of the anti-blocking rod (15) is connected to the output shaft of the anti-blocking actuator (16), and the other end swings with the rotation of the anti-blocking actuator (16). One end of the swinging arc path is directly opposite the second glue injection port (13).

6. The two-color molding die according to claim 1, characterized in that, The outer diameter of the anti-blocking rod (15) is smaller than the inner diameter of the second injection port (13), and an annular vent (14) is formed between the anti-blocking rod (15) and the second injection port (13); the upper surface of the second left punch (402) and / or the second right punch (502) is provided with a vent (14) that communicates with the upper edge of the end of the second cavity (7).

7. The two-color molding die according to claim 1, characterized in that, The outer circumferential surfaces of the first left punch (401) and the first right punch (501) are provided with recessed textures (27), and the depth of the textures (27) is sufficient to completely separate the inner wall of the outer layer from the first left punch (401) and the first right punch (501) when the outer layer shrinks.

8. The two-color molding die according to claim 2, characterized in that, The first left punch (401) and the first right punch (501) are respectively provided with male heads (28) and female mouths (29) that cooperate with each other at their opposite ends. When the first left punch (401) and the first right punch (501) are inserted into the die cavity (3) at the same time, they are positioned by the male head (28) and the female mouth (29), and the annular end faces (30) of the male head (28) and the female mouth (29) are tightly fitted. The mating structure of the second left punch (402) and the second right punch (502) is the same as that of the first left punch (401) and the first right punch (501).

9. A method for injection molding a double-ended flared tube, characterized in that, Using any one of the two-color molding dies described in claims 1 to 8, injection molding is performed through the following specific steps: a. First, the fixed mold (2) and the movable mold (1) are closed together. Then, the first left punch (401) and the first right punch (501) are closed together to form the first cavity (6). The anti-blocking rod (15) is inserted into the second injection port (13) and abuts against the first left punch (401) or the first right punch (501). Glue is injected into the first cavity (6) through the first injection port (12). Then the first cavity (6) is cooled to form the outer layer (31) of the double-headed flared tube. b. Pull out the first left punch (401) and the first right punch (501), remove the anti-blocking rod (15), switch the second left punch (402) and the second right punch (502) into the cavity (3), the second left punch (402), the second right punch (502) and the outer layer (31) form the second cavity (7), inject glue into the second cavity (7) through the second glue injection port (13), and then cool the second cavity (7) to form the inner layer (32) of the double-headed flared tube. c. Pull out the second left punch (402) and the second right punch (502), lift the movable mold (1) so that the anti-blocking rod (15) is passively inserted into the second injection port (13) and pushes the double-headed flared tube to disengage from the movable mold (1) and fall off; d. Remove the double-ended flared tube and repeat steps a to c.

10. The injection molding method according to claim 9, characterized in that, When implementing step b, after the anti-blocking rod (15) is withdrawn, the anti-blocking rod (15) is rotated at a certain angle so that the lower end of the anti-blocking rod (15) is deviated from the second injection port (13) to make room for injection. When implementing step c, the anti-blocking rod (15) is reset to push the double-headed flared tube to achieve automatic demolding.

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