A sealing strip corner joint forming method based on an injection mold

Abstract

The application provides a sealing strip corner joint forming method based on an injection mold. Two sealing strips are respectively placed in a first positioning cavity and a second positioning cavity, and the ends of the two sealing strips abut against a first step portion and a second step portion respectively. After clamping, a first limiting convex portion at the bottom of an upper mold plate and a first limiting surface, a second limiting surface, and the first step portion jointly limit a sealing strip in the first positioning cavity, and a second limiting convex portion at the bottom of the upper mold plate and perpendicular to the first limiting convex portion and a third limiting surface, a fourth limiting surface, and the second step portion jointly limit another sealing strip in the second positioning cavity. Then, injection is performed through an injection device. Position movement in the corner joint injection process is reduced. Material forms a forming section in a forming cavity, and the two ends of the forming section are respectively connected with the end of the sealing strip and the end of another sealing strip to form an integrated product, so that the product quality of the entire sealing strip after injection molding is improved.

Description

Technical Field

[0001] This invention relates to the field of injection molding machine technology, and specifically to a method for forming corner joints of sealing strips based on injection molds. Background Technology

[0002] With the development of injection molding technology, injection molding machines can be used to injection mold a variety of products, such as single-sided products and multi-strip products. Sealing strips are a type of multi-sided product with sealing performance, which are widely used in various fields that require sealing, such as automotive sealing strips. Automotive sealing strips can fill gaps in the car body to achieve waterproofing, dustproofing, sound insulation, noise reduction, and shock absorption, thereby ensuring driving comfort, protecting the vehicle structure, and extending the life of parts. At the same time, they can isolate wind noise and external environmental noise at high speeds, significantly reducing the decibel level inside the car and improving the overall quietness of the vehicle. They are a key component in maintaining the environmental adaptability of the vehicle. In the production process of automotive sealing strips, two sealing strips are often injection molded first, and then the two sealing strips are connected by injection molding corners through an injection mold to obtain a complete sealing strip.

[0003] For example, Chinese patent document No. 201810498070.2, published on October 12, 2018, discloses a dual-station injection molding die for automotive sealing strips, including an upper die and a lower die. The upper die consists of a panel, a hot runner plate, and a sprue plate. The panel has a main sprue, the hot runner plate has a hot runner, and the sprue plate has a sub-sprue and guide pillars. The lower die consists of a mold plate, a machine plate, and a base plate. The mold plate is a plate-shaped steel component and has a core block, guide shaft, cavity block, submersible sprue, guide hook, and guide pillar holes. The machine plate is a plate-shaped steel component and has a C-rack, D-rack, coupling gear, lever, connecting block, damping torsion spring, damping rod, core slider, core hinge, push spring, and hydraulic cylinder. The base plate is a rectangular plate-shaped steel component, and the top of the base plate has a rectangular groove in the left-right direction, called a C-groove.

[0004] The aforementioned literature describes a method where the core block is opened and reset by rotating upwards and downwards using a hydraulic cylinder. The opening of the core block allows for the insertion and removal of the sealing strip. However, this process requires the coordination of a coupling gear and a damping spring, making the entire structure complex. Furthermore, the upward rotation during operation necessitates the sliding of the core block's guide shaft along the guide hook's groove. This results in varying sliding distances during unfolding, leading to different corner joint effects. Additionally, the cavity block is only set at a right angle, requiring the ends of the two sealing strips to abut against the right angle. This limits the amount of molding material that can be accommodated at the right angle, thus affecting the joint's fit. For corner molding, if the ends of the two sealing strips are not inserted into the right angle, the ends of the sealing strips will be limited, thus achieving reliable and effective corner molding. For injection molding machines, the upper mold plate presses down to generate a large pressure, which exerts downward pressure on the sealing strip located in the molding cavity. Most existing injection molding machines use four columns arranged in a square. This means that the upper mold plate forms only a linear guiding constraint on the columns, resulting in a linear force acting on the sealing strip. Consequently, the constraint force acting on the sealing strip has a small effective area, which can easily cause the sealing strip to arch during the sealing process, thus affecting the corner molding effect. Summary of the Invention

[0005] The purpose of this invention is to provide a method for forming corner joints of sealing strips based on injection molds. By precisely positioning the two sealing strips, the method reduces positional movement during the corner injection molding process and improves the product quality of the entire sealing strip after injection molding.

[0006] This invention provides the following technical solution: a method for forming corner joints of sealing strips based on injection molds, implemented by injection molding equipment. The injection molding equipment includes a mold base and an upper mold base mounted on a machine base. An injection mold and a column are disposed between the lower mold base and the upper mold base. The lower mold plate of the injection mold is provided with a first fixing block, a positioning unit, and a second fixing block. The positioning unit and the first fixing block form a first positioning cavity, and the positioning unit and the second fixing block form a second positioning cavity. The positioning unit is detachably mounted from the lower mold plate. The column is arranged in a trapezoidal shape in the plane of the upper mold base. The positioning unit is located at the corner and has a first boss and a second boss protruding towards the first fixing block and the second fixing block, respectively. The first limiting boss and the second limiting boss are perpendicular to each other. The method also includes the following steps: S1. Drive the upper template on the upper mold base to detach from the lower template on the lower mold base, insert a sealing strip into the first positioning cavity along the width direction of the second fixing block and place the sealing strip between two widely spaced columns, with the end of the sealing strip abutting against the first step portion in the first positioning cavity; insert another sealing strip into the second positioning cavity along the length direction of the second fixing block and place the other sealing strip behind the two widely spaced columns, with the end of the other sealing strip abutting against the second step portion in the second positioning cavity; S2. Drive the upper and lower mold plates on the upper mold base to close the mold, so that the first limiting protrusion and the first step at the bottom of the upper mold plate are jointly limited to a sealing strip in the first positioning cavity; so that the second limiting protrusion and the second step at the bottom of the upper mold plate are jointly limited to another sealing strip in the second positioning cavity; inject material into the molding cavity formed by the first and second positioning cavities to perform molding; S3. The upper and lower templates are opened, and the sealing strip, the first positioning unit, and the second positioning unit, which are formed as a whole, are taken out at the same time.

[0007] The above setup involves placing a positioning unit on the upper template, forming a first positioning cavity and a second positioning cavity between the positioning unit, the first fixing block, and the second fixing block. A sealing strip is inserted into two wider positioning posts, with its end abutting against the second step. Another sealing strip is inserted between two more spaced posts, with its end abutting against the first step. The first and second steps limit the end positions of the sealing strips at the two corners. The four posts form a trapezoid, and the first and second steps, along with the trapezoidal posts, work together to achieve the desired effect. This design ensures that when the upper and lower mold plates are closed, a sealing strip is confined within the first positioning cavity by the first limiting protrusion and the first step at the bottom of the upper mold plate; and another sealing strip is confined within the second positioning cavity by the second limiting protrusion and the second step at the bottom of the upper mold plate. This prevents the sealing strip from moving within the first and second positioning cavities. Furthermore, the two pillars located on the inclined side of the trapezoid form an inclined guiding constraint force that acts on the sealing strip. The area of ​​the inclined constraint force acting on the sealing strip is increased, thereby preventing imbalance during mold closing that could cause the sealing strip to arch in the middle, thus improving the corner joint effect.

[0008] Furthermore, the lower mold base is provided with a base plate, and the base plate is provided with a limiting component on both sides of the lower mold plate. The limiting component includes a locking member and a limiting body arranged along the width direction of the lower mold plate. After the locking member passes through the limiting body, it fixes the limiting body on the base plate.

[0009] The above settings allow the limiting bodies on both sides of the lower template to press against the lower template from both sides, that is, the two sides of the lower template abut against the limiting bodies respectively, thereby fixing the lower template to the base plate.

[0010] Furthermore, two positioning units are provided, which are symmetrically arranged relative to the first fixing block. Two second fixing blocks are provided, with a second fixing block corresponding to one side of each positioning unit.

[0011] The above setup, by using two positioning units, allows for the corner connection of two sets of sealing strips through an upper template and a lower template.

[0012] Furthermore, each positioning unit includes a first positioning unit and a second positioning unit. In step S2, after the upper template and the lower template are joined, The first limiting protrusion is located in the first positioning cavity, and the second limiting protrusion is located in the second positioning cavity. The first limiting protrusion is obliquely downward protruding from the bottom of the upper template into the first positioning cavity and towards the side closer to the first positioning unit body. The surface of the first limiting protrusion forms a first limiting curved surface. The second limiting protrusion is provided to protrude obliquely downward from the bottom of the upper template into the second positioning cavity and towards the side closer to the second positioning unit body, and the surface of the second limiting protrusion forms a second limiting curved surface.

[0013] The above settings, through the first limiting curved surface and the second limiting curved surface respectively abutting against the two sealing strips, can respectively increase the friction of the sealing strips in the first positioning cavity and the second positioning cavity.

[0014] Furthermore, a first boss is formed by one side of the first positioning unit body protruding towards the second fixing block, and a second boss is formed by one side of the second positioning unit body protruding towards the second fixing block. The first boss and the second boss are perpendicular to each other, and the adjacent edges of the second fixing block form forming cavities with the first boss and the second boss respectively. A first limiting surface is provided on the first positioning unit, and a third limiting surface is provided on the second positioning unit. Step S1 further includes: one side of a sealing strip abuts against the first limiting surface formed in the first positioning cavity and on one side wall of the first positioning unit body, and the other side of a sealing strip abuts against the first positioning cavity and is formed on one side of the second fixing block. On the second limiting surface of the wall; one side of the other sealing strip abuts against the third limiting surface inside the second positioning cavity and formed on one side wall of the second positioning unit body, and the other side of the other sealing strip abuts against the fourth limiting surface inside the second positioning cavity and formed on the other side wall of the second fixing block; in step S2, after the upper template and the lower template are closed, a sealing strip located at the bottom of the upper template and whose first limiting protrusion, together with the first limiting surface and the second limiting surface, is limited to the first positioning cavity, and another sealing strip located at the bottom of the upper template and whose second limiting protrusion is perpendicular to the first limiting protrusion, together with the third limiting surface, the fourth limiting surface, and the second step portion, is limited to the second positioning cavity.

[0015] The above configuration, after mold closing, within the first positioning cavity, allows a sealing strip, jointly constrained by the first limiting protrusion and the first step at the bottom of the upper mold plate, to exert a slight pressure from both sides of the sealing strip through the combined action of the first limiting body and the second limiting surface. This increases the friction between the sealing strip and the first and second limiting surfaces within the first positioning cavity, effectively resisting the thrust generated on the sealing strip during material accumulation in the molding cavity during injection molding. This prevents minor movement of the sealing strip from creating a small gap between it and the first step, thus avoiding affecting the molding effect at the connection between the molding section and the end of the sealing strip within the molding cavity. Within the second positioning cavity, the second limiting protrusion, perpendicular to the first limiting protrusion, along with the third, fourth, and second limiting surfaces, jointly constrains the sealing strip within the first positioning cavity. The second sealing strip inside the positioning cavity causes the second limiting body and the fourth limiting surface to work together to form a slight extrusion from both sides of the other sealing strip, thereby increasing the friction between the other sealing strip and the second positioning cavity. This effectively resists the thrust generated by the material accumulation process in the molding cavity during injection molding on the other sealing strip, preventing the other sealing strip from moving slightly and creating a small gap between it and the second step. This avoids affecting the molding effect at the connection between the molding section in the molding cavity and the end of the other sealing strip, thus enabling the two ends of the molding section in the molding cavity to be connected to the ends of one sealing strip and the other sealing strip respectively to form a good molding effect. By accurately positioning the two sealing strips, the positional movement during the corner injection molding process is reduced, thereby improving the product quality of the entire sealing strip after injection molding.

[0016] Furthermore, in step S1, a first limiting body is provided on the first limiting surface, protruding from the first limiting surface into the first positioning cavity. There is one or more first limiting bodies. The first limiting body extends from the entrance of the first positioning cavity along the length direction of the first positioning unit towards the end near the first step. A gap is formed between the first limiting body and the first step. A first guide surface is formed at the end of the first limiting body near the entrance of the first positioning cavity.

[0017] The above configuration guides the sealing strip inserted into the first positioning cavity via the first guide surface. Simultaneously, during the insertion of the sealing strip into the first positioning cavity, the first limiting body and the second limiting surface work together to create a slight compression from both sides of the sealing strip. This increases the friction between the sealing strip and the first positioning cavity, effectively resisting the thrust generated on the sealing strip during the material accumulation process in the molding cavity during injection molding. This prevents the sealing strip from shifting slightly, which could create a small gap between the sealing strip and the first step, thus affecting the molding effect at the connection. Furthermore, because a gap forms between the first limiting body and the first step, after the end of the sealing strip abuts against the first step, the material properties of the sealing strip allow the deformation caused by the slight compression to recover, thereby avoiding any impact on the molding effect at the connection.

[0018] Furthermore, in step S1, the middle position of the second limiting surface is recessed along the length direction of the second fixing block to form a first recessed portion, the surface of the first recessed portion forms a first recessed curved surface, one end of the second limiting surface extends to the bottom of the first positioning cavity, and the other end of the second limiting surface extends to the first limiting curved surface.

[0019] The above settings can increase the contact area with the sealing strip, thereby increasing the friction between the sealing strip and the second limiting surface.

[0020] Furthermore, in step S1, a second limiting body is provided on the third limiting surface, protruding from the third limiting surface into the second positioning cavity. There is one or more second limiting bodies. The second limiting body extends from the entrance of the second positioning cavity along the length direction of the second positioning unit towards one end near the second step. A gap is formed between the second limiting body and the second step. A second guide surface is formed at one end of the second limiting body near the entrance of the second positioning cavity.

[0021] The above configuration guides the second sealing strip inserted into the second positioning cavity via the second guide surface. Simultaneously, during the insertion of the other sealing strip into the second positioning cavity, the second limiting body and the fourth limiting surface work together to create a slight compression from both sides of the other sealing strip. This increases the friction between the other sealing strip and the second positioning cavity, effectively resisting the thrust generated by the material buildup process within the molding cavity during injection molding. This prevents the other sealing strip from experiencing slight movement, which could create a small gap between it and the second step, thus affecting the molding effect at the connection. Furthermore, due to the gap between the second limiting body and the second step, after the end of the other sealing strip abuts against the second step, the material properties of the sealing strip allow the deformation caused by the slight compression to recover, thus avoiding any impact on the molding effect at the connection.

[0022] Furthermore, in step S1, the middle position of the fourth limiting surface is recessed along the width direction of the second fixing block to form a second recessed portion, the surface of the second recessed portion forms a second recessed curved surface, one end of the fourth limiting surface extends to the bottom of the second positioning cavity, and the other end of the fourth limiting surface extends to the second limiting curved surface.

[0023] The above settings can increase the contact area with the sealing strip, thereby increasing the friction between the sealing strip and the fourth limiting surface.

[0024] Furthermore, the injection molding equipment also includes a material storage device disposed on the upper mold base, an injection molding device disposed above the material storage device, an injection mold located between the upper mold base and the lower mold base, and a first drive assembly for driving the upper mold base, the first drive assembly being connected to four columns.

[0025] The above settings involve the first drive component driving the upper mold base to descend, causing the upper and lower mold plates to close, thereby achieving the mold closing operation and affecting the overall molding effect. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 .

[0027] Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 .

[0028] Figure 3 This is a schematic diagram of the injection mold structure.

[0029] Figure 4 Localized explosion of injection mold Figure 1 .

[0030] Figure 5 Localized explosion of injection mold Figure 2 .

[0031] Figure 6 This is the front view of the injection mold.

[0032] Figure 7 This is a top view of the injection mold.

[0033] Figure 8 for Figure 7 Enlarged view of point A in the middle.

[0034] Figure 9 This is a side view of the injection mold.

[0035] Figure 10 This is a schematic diagram showing the arrangement of the columns on the upper mold base.

[0036] Figure 11 This is a flowchart of the workflow of the present invention. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0038] like Figure 1-2As shown, this invention provides a method for forming corner joints of sealing strips based on injection molds, implemented by an injection molding machine. The injection molding machine includes a lower mold base z2 mounted on a machine base z1, a material storage device mounted on an upper mold base z3, an injection molding device mounted above the material storage device, an injection mold located between the upper mold base z3 and the lower mold base z2, and a first driving assembly for driving the upper mold base z3. In this embodiment, the material storage device includes an injection tube z4, a connecting plate z5, and a second driving assembly z6 and a guide rod z7 arranged diagonally. One end of the injection tube z4 is connected to the connecting plate z5 and located at the center of the connecting plate z5. The other end of the injection tube z4 forms an injection port and can be inserted into the injection port of the upper mold base z3 after moving under the drive of the second driving assembly z6. There are two second driving assemblies z6 and two guide rods z7. The two ends of the guide rod z7 are connected to the upper mold base z3 and the connecting plate z5 respectively. The guide rod z7 and the connecting plate z5 are slidably connected and serve as guides. The injection molding device is connected to the connecting plate z5 so that the connecting plate z5 can be driven to move vertically along the guide rod z7 by the second drive assembly z6, thereby driving the injection molding device to move up and down. The injection molding device includes a third drive assembly z8, a second guide rod z9, a sliding member z10 and a push rod z11. The second guide rod z9 is connected to the connecting plate z5, and the sliding member z10 is slidably sleeved on the second guide rod z9. The output end of the third drive assembly z8 is connected to one end of the sliding member z10, and the other end of the sliding member z10 is connected to the push rod z11. A rotary motor z100 is provided on the sliding member z10, and the rotary motor drives the screw (not shown in the figure) inside the injection tube z4 of z100 to rotate.

[0039] The third drive component z8 can drive the slider z10 to move vertically along the guide rod z9, thereby driving the push rod z11 to move up and down, so that the push rod z11 can be inserted into the injection tube and push the material in the injection tube to the injection port, so that the material is ejected from the injection port to the injection port. The second drive component z6 and the third drive component z8 are both drive cylinders.

[0040] like Figure 1-2 as well as Figure 10As shown, the first drive assembly is located inside the machine base Z1. The first drive assembly includes a mold closing cylinder and a mold locking cylinder. The first drive assembly is connected to the upper mold base via the column Z12, driving the upper mold base to perform mold closing and locking. There are four columns Z12 arranged in a trapezoidal shape on the machine base Z1, specifically an isosceles trapezoidal arrangement. The distance between two columns on one side is greater than the distance between two columns on the other side, and the distance between two columns on one side is greater than the distance to the lower mold plate 4. The distance between two columns on the other side is less than the distance to the lower mold plate 4. By setting a larger distance between the columns on one side, the size of the lower mold plate 4 can be adjusted, and the mold closing and locking can also be adjusted accordingly. The constraint force exerted by the four columns on the upper mold plate is more concentrated, preventing the sealing strip from arching in the middle. In this embodiment, the other end of the column z12 passes through the lower mold base z2 and the upper mold base z3 in sequence and is connected to the connecting block z13 connected to the upper mold base z3. In this way, after the first driving component (not shown in the figure) drives the column z12 to move, it can drive the upper mold base z3 to descend, so that the upper mold plate 3 and the lower mold plate 4 are closed. When the mold is closed, the first driving component located on one side of the lower mold base z2 can apply force from directly above the lower mold plate 4. This results in better tightness after mold closure and avoids the material in the molding cavity from undergoing slight arching deformation after molding, which would affect the overall molding effect.

[0041] like Figure 3 , 5 As shown in Figure 7, the injection mold includes a base 1, a base plate 2, an upper mold plate 3, and a lower mold plate 4 disposed on the base plate 2. The base 1 is disposed on the lower mold base z2, and the base plate 2 is disposed on the base 1. Limiting components 7 are provided on the base plate 2 on both sides of the lower mold plate 4. The limiting components 7 include locking members 6 and limiting bodies 5 disposed along the width direction of the lower mold plate 4. After the locking members 6 pass through the limiting bodies 5, they fix the limiting bodies 5 on the base plate 2, thereby allowing the limiting bodies 5 on both sides of the lower mold plate 4 to press against the lower mold plate 4 from both sides, that is, the two sides of the lower mold plate 4 respectively abut against the limiting bodies 5, thereby fixing the lower mold plate 4 on the base plate 2. In this embodiment, the locking member 6 is a bolt.

[0042] like Figure 3 , Figures 5-7As shown, the lower template 4 is provided with a first fixing block 8, a positioning unit 9 located on one side of the first fixing block 8, and a second fixing block 10 located on one side of the positioning unit 9. The first fixing block 8 is fixed to the lower template 4, the second fixing block 10 is fixed to the lower template 4, and the positioning unit 9 is detachably mounted on the lower template 4. Each positioning unit 9 includes a first positioning unit body 91 and a second positioning unit body 92. The first positioning unit body 91 and the second positioning unit body 92 are perpendicularly arranged along the adjacent edges of the first fixing block 8. The lower template 4 is provided with a first recessed hole (not shown in the figure) and a second recessed hole (not shown in the figure). The first recessed hole is matched with a first protrusion (not shown in the figure) protruding from the bottom of the first positioning unit body 91, and the second recessed hole is matched with a second protrusion (not shown in the figure) protruding from the bottom of the second positioning unit body 92. This can restrict the first positioning unit body 91 and the second positioning unit body 92. The two positioning units 92 move on the lower template 4 to ensure the positioning and sealing of the sealing strip by different positioning cavities and the injection molding effect of the molding cavity 17. At the same time, when the product is molded and connected as a whole, it is also easy to disassemble and remove the first positioning unit 91 and the second positioning unit 92 from the lower template 4. In this embodiment, two positioning units 9 are provided, each positioning unit 9 is symmetrically arranged relative to the first fixing block 8, and two second fixing blocks 10 are provided. Each side of each positioning unit 9 is respectively provided with a second fixing block 10. The two sets of sealing strips to be connected at the corners are respectively placed into one positioning unit and the corresponding first fixing block 8 and second fixing block 10 to achieve corner connection. The other set of corners to be connected can be placed into another positioning unit and the corresponding first fixing block and second fixing block 10 to achieve corner connection of another set of sealing strips, thereby realizing the corner connection of two sets of sealing strips in one injection.

[0043] like Figure 3 , Figures 5-7As shown, a first positioning cavity 11 is formed between the first positioning unit 91 and the second fixing block 10, extending along the width direction of the second fixing block 10. A first step portion 12 is provided within the first positioning cavity 11. A first boss 13 is formed on one side of the first positioning unit 91 protruding towards the second fixing block 10. The first step portion 12 located within the first positioning cavity 11 is located at one end of the first boss 13. A second positioning cavity 14 is formed between the second positioning unit 92 and the second fixing block 10, extending along the length direction of the second fixing block 10. A second step portion 15 is provided within the second positioning cavity 14. One side of the second positioning unit 92 protrudes towards the second fixing block 10. A second boss 16 is formed by a protrusion, and a second step 15 is located at one end of the second boss 16 within the second positioning cavity 14. This allows the ends of the sealing strips placed in different positioning cavities to abut against the first step 12 and the second step 15 respectively, so that the ends of the different sealing strips are exactly at the position where the molding cavity 17 communicates with the two positioning cavities. After the upper mold plate 3 and the lower mold plate 4 are closed and pressed together, the connection effect with the different sealing strips after injection molding is good, effectively preventing the injection plastic in the molding cavity 17 from flowing into the positioning cavity due to deviation in the sealing strip limiting effect, so as to affect the effect of injection molding connection to form an integral unit.

[0044] like Figures 3-9 As shown, after the upper template 3 and the lower template 4 are closed, the first limiting protrusion a1 is located in the first positioning cavity 11, and the second limiting protrusion a2 is located in the second positioning cavity 14. The first limiting protrusion a1 is obliquely downward protruding from the bottom of the upper template 3 toward the first positioning cavity 11 and toward the side closer to the first positioning unit body 91. The surface of the first limiting protrusion a1 forms a first limiting curved surface a3. The second limiting protrusion a2 is obliquely downward protruding from the bottom of the upper template 3 toward the second positioning cavity 14 and toward the side closer to the second positioning unit body 92. The surface of the second limiting protrusion a2 forms a second limiting curved surface a4. The first limiting curved surface a3 and the second limiting curved surface a4 abut against the two sealing strips respectively, which can increase the friction of the sealing strips in the first positioning cavity 11 and the second positioning cavity 14 respectively.

[0045] like Figures 6-9As shown, a first limiting surface a5 is formed inside the first positioning cavity 11 and on one side wall of the first positioning unit 91. A first limiting body a6 protrudes from the first limiting surface a5 into the first positioning cavity 11. There is one or more first limiting bodies a6. Each first limiting body a6 extends from the entrance of the first positioning cavity 11 along the length of the first positioning unit 91 towards one end near the first step portion 12, forming a gap between the first limiting body a6 and the first step portion 12. A first guide surface a7 is formed at one end of the first limiting body a6 near the entrance of the first positioning cavity 11, guiding a sealing strip inserted into the first positioning cavity 11. A first recessed portion a8 is formed at the middle of the second limiting surface a7 along the length of the second fixing block. A first recessed curved surface a9 is formed on the surface of the first recessed portion a8. One end of the second limiting surface a7 extends to the bottom of the first positioning cavity 11. The other end of the second limiting surface a7 extends to the first limiting curved surface a3. In this way, during the process of inserting a sealing strip into the first positioning cavity 11, the first limiting body a6 and the second limiting surface a7 work together to form a small extrusion from both sides of the sealing strip, thereby increasing the friction between the sealing strip and the first limiting surface a5 and the second limiting surface a7 in the first positioning cavity 11. This effectively resists the thrust generated by the material accumulation process in the molding cavity during injection molding on the sealing strip, preventing the sealing strip from moving slightly and causing a small gap between the sealing strip and the first step portion 12, which would affect the molding effect at the connection. At the same time, since a gap is formed between the first limiting body a6 and the first step portion 12, after the end of the sealing strip abuts against the first step portion 12, the deformation caused by the small extrusion is restored due to the sealing strip being made of elastic material, thereby avoiding affecting the molding effect at the connection between the molding section in the molding cavity and the end of the sealing strip.

[0046] like Figures 6-9As shown, a third limiting surface a10 is formed inside the second positioning cavity 14 and on one side wall of the second positioning unit 92. A second limiting body a11 is provided on the third limiting surface a10, protruding from the third limiting surface a10 into the second positioning cavity 14. There is one or more second limiting bodies a11. Each second limiting body a11 extends from the entrance of the second positioning cavity 14 along the length of the second positioning unit 92 towards one end near the second step portion 15. The second limiting body a11 and the second step portion 15 are positioned close to each other. A gap is formed. A second guide surface a12 is formed at one end of the second limiting body a11 near the entrance of the second positioning cavity 14. The second guide surface a12 guides the other sealing strip inserted into the second positioning cavity 14. A second recessed portion a13 is formed at the middle of the fourth limiting surface a15 along the width direction of the second fixing block. A second recessed curved surface a14 is formed on the surface of the second recessed portion a13. One end of the fourth limiting surface a15 extends to the bottom of the second positioning cavity 14. The other end of the fourth limiting surface a15... The end extends to the second limiting curved surface a4. In this way, during the insertion of the other sealing strip into the second positioning cavity 14, the second limiting body a11 and the fourth limiting surface a15 work together to form a small extrusion from both sides of the other sealing strip, thereby increasing the friction between the other sealing strip and the second positioning cavity 14. This effectively resists the thrust generated by the material accumulation process in the molding cavity during injection molding on the other sealing strip, preventing the other sealing strip from moving slightly and causing a small gap between the other sealing strip and the second step portion 15, which would affect the molding effect at the connection. At the same time, since a gap is formed between the second limiting body a11 and the second step portion 15, after the end of the other sealing strip abuts against the second step portion 15, the deformation caused by the small extrusion can be restored based on the material properties of the sealing strip, thereby avoiding affecting the molding effect at the connection between the molding section in the molding cavity and the end of the other sealing strip. This allows the two ends of the molding section in the molding cavity to be connected to the end of one sealing strip and the end of the other sealing strip respectively, forming a good molding effect.

[0047] like Figure 3 , Figure 5-7 , Figure 9As shown, a molding cavity 17 is formed between the first positioning unit 91, the second positioning unit 92, and the second fixing block 10. Specifically, the molding cavity 17 is formed by the first boss 13 and the second boss 16 being perpendicularly arranged, and the adjacent edges of the second fixing block 10 forming the molding cavity 17 with the first boss 13 and the second boss 16 respectively. The two ends of the molding cavity 17 are connected to the first positioning cavity 11 and the second positioning cavity 14 respectively. At the same time, the distance from the first limiting surface a5 in the first positioning cavity 11 to the second fixing block 10 is greater than the distance from the first boss 13 to the second fixing block 10, and the distance from the third limiting surface a10 in the second positioning cavity 14 is greater than the distance from the first boss 13 to the second fixing block 10. The distance to the second fixing block 10 is greater than the distance to the second boss 16, which allows the end of one sealing strip to abut against the first step 12 in the first positioning cavity 11, so that the part of the sealing strip to be connected is located at the connection between the molding cavity 17 and the first positioning cavity 11. At the same time, the end of another sealing strip abuts against the second step 15 in the second positioning cavity 14, so that the part of the other sealing strip to be connected is located at the connection between the molding cavity 17 and the second positioning cavity 14. After the mold is closed, the connection effect between the different sealing strips and the injection-molded parts in the molding cavity 17 is better.

[0048] like Figure 5 As shown, the upper mold plate 3 is provided with an injection port 20. After the upper mold plate 3 and the lower mold plate 4 are closed, the injection port 20 is connected to the injection channel (not shown in the figure). The injection channel is connected to the molding cavity 17 so that after the mold is closed, the material is injected into the injection channel through the injection port 20, and then the material is injected into the molding cavity 17 and formed in the molding cavity 17 to form a molding segment. Thus, the two ends of the molding segment are connected to the sealing strip in the first positioning cavity 11 and the sealing strip in the second positioning cavity 14 respectively to form an integral part.

[0049] like Figure 11 As shown, a method for forming corner joints of sealing strips based on injection molds includes the following specific steps: S1. The upper template on the upper mold base z3 is driven to detach from the lower template 4 on the lower mold base z2 by the first driving component. Two positioning units 9 are placed on the lower template 4. A sealing strip is inserted into the first positioning cavity 11 along the width direction of the second fixing block 8 and the sealing strip is located on the rear side of the two columns with large spacing. After the end of the sealing strip abuts against the first step portion 1211 in the first positioning cavity 11, one side of the sealing strip abuts against the first limiting surface a5 formed on the side wall of the first positioning unit body in the first positioning cavity, and the other side of the sealing strip abuts against the second limiting surface a7 formed on the side wall of the second fixing block 10 in the first positioning cavity 11. Another sealing strip is inserted into the second positioning cavity along the length of the second fixing block 10. The other sealing strip is located between two widely spaced columns. After the end of the other sealing strip abuts against the second step in the second positioning cavity 14, one side of the other sealing strip abuts against the third limiting surface a10 formed on one side wall of the second positioning unit body in the second positioning cavity 14, and the other side of the other sealing strip abuts against the fourth limiting surface a15 formed on the other side wall of the second fixing block in the second positioning cavity. S2. The first driving component drives the upper mold plate on the upper mold base z3 to close the mold with the lower mold plate 4, so that the first limiting protrusion at the bottom of the upper mold plate, together with the first limiting surface a5, the second limiting surface a7, and the first step portion, is jointly limited to a sealing strip in the first positioning cavity; at the same time, the second limiting protrusion located at the bottom of the upper mold plate and perpendicular to the first limiting protrusion, together with the third limiting surface a10, the fourth limiting surface a15, and the second step portion, is jointly limited to another sealing strip in the second positioning cavity. The second drive assembly on the upper mold base z3 drives the injection tube of the material storage device to be inserted into the injection port of the upper mold base z3. Then, the third drive assembly on the injection device drives the push rod of the injection device to inject the material in the injection tube into the injection port, so that the material flows into the molding cavity through the injection channel connected to the injection port and is formed in the molding cavity to form the molding section. S3. After the molding section is connected to one sealing strip and another sealing strip to form an integral part, the upper mold plate 3 and the lower mold plate 4 are opened. The integral sealing strip, the first positioning unit 91 and the second positioning unit 92 are taken out from the lower mold plate at the same time. After removing the integral sealing strip, the first positioning unit 91 and the second positioning unit 92 are reset to the lower mold plate 4 for the next injection molding.

[0050] In this embodiment, by setting two positioning units and two corresponding first limiting protrusions and second limiting protrusions on the upper template, it is possible to achieve the corner joint operation of two sets of sealing strips in one mold closing and mold opening.

[0051] The working principle of this invention is as follows: Two sealing strips are placed into the vertically arranged first positioning cavity 11 and second positioning cavity 14 along the width and length directions of the first fixing block 8, respectively, so that the ends of the two sealing strips abut against the first step portion 12 and the second step portion 15, respectively. Then, the upper mold and the lower mold are driven to close. After the mold is closed, a sealing strip can be confined in the first positioning cavity by the first limiting protrusion a1 at the bottom of the upper mold, the first limiting surface a5, the second limiting surface a7, and the first step portion 12. At the same time, the sealing strip located at the bottom of the upper mold and perpendicular to the first limiting protrusion a1 is also confined. The second limiting protrusion a2, together with the third limiting surface a10, the fourth limiting surface a15, and the second step, is positioned within the second positioning cavity as another sealing strip. Then, the material in the injection tube of the storage device is pushed by the push rod of the injection molding device for injection molding. The material forms a molding section in the molding cavity 17, and the two ends of the molding section are respectively connected to the end of one sealing strip and the end of another sealing strip to form an integral piece. By accurately positioning the two sealing strips, the positional movement during the corner injection molding process is reduced, thereby improving the product quality of the entire sealing strip after injection molding.

Claims

1. A method for forming corner joints of sealing strips based on injection molds, implemented by injection molding equipment, the injection molding equipment including a lower mold base and an upper mold base mounted on a machine base, an injection mold and a column disposed between the lower mold base and the upper mold base, the lower mold plate of the injection mold being provided with a first fixing block, a positioning unit and a second fixing block, the positioning unit and the first fixing block forming a first positioning cavity, and the positioning unit and the second fixing block forming a second positioning cavity; characterized in that: The positioning unit and the lower template are detachably installed. The column is arranged in a trapezoidal shape in the plane of the upper mold base. The positioning unit is located at the corner and has a first step and a second step. The following steps are also included: S1. Drive the upper template on the upper mold base to detach from the lower template on the lower mold base, insert a sealing strip into the first positioning cavity along the width direction of the second fixing block, and place the sealing strip behind the two columns with a large distance between them. The end of the sealing strip abuts against the first step in the first positioning cavity. Insert another sealing strip into the second positioning cavity along the length of the second fixing block, with the other sealing strip positioned between two widely spaced columns, and the end of the other sealing strip abutting against the second step portion inside the second positioning cavity; S2. Drive the upper and lower mold plates on the upper mold base to close the mold, so that the first limiting protrusion and the first step at the bottom of the upper mold plate are jointly limited to a sealing strip in the first positioning cavity; so that the second limiting protrusion and the second step at the bottom of the upper mold plate are jointly limited to another sealing strip in the second positioning cavity; inject material into the molding cavity formed by the first and second positioning cavities to perform molding; S3. The upper and lower templates are opened, and the sealing strip, the first positioning unit, and the second positioning unit, which are formed as a whole, are taken out at the same time.

2. The method for forming corner joints of sealing strips based on injection molds according to claim 1, characterized in that: The lower mold base is provided with a base plate, and the base plate is provided with a bottom plate. Limiting components are provided on both sides of the lower mold plate. The limiting components include locking members and limiting bodies arranged along the width direction of the lower mold plate. After the locking members pass through the limiting bodies, they fix the limiting bodies to the bottom plate.

3. The method for forming corner joints of sealing strips based on injection molds according to claim 1, characterized in that: Two positioning units are provided, and the two positioning units are symmetrically arranged relative to the first fixing block. Two second fixing blocks are provided, and each positioning unit has a second fixing block on one side.

4. The method for forming corner joints of sealing strips based on injection molds according to claim 1, characterized in that: Each positioning unit includes a first positioning unit and a second positioning unit. In step S2, after the upper template and the lower template are joined together... The first limiting protrusion is located in the first positioning cavity, and the second limiting protrusion is located in the second positioning cavity. The first limiting protrusion is obliquely downward protruding from the bottom of the upper template into the first positioning cavity and towards the side closer to the first positioning unit body. The surface of the first limiting protrusion forms a first limiting curved surface. The second limiting protrusion is provided to protrude obliquely downward from the bottom of the upper template into the second positioning cavity and towards the side closer to the second positioning unit body, and the surface of the second limiting protrusion forms a second limiting curved surface.

5. The method for forming corner joints of sealing strips based on injection molds according to claim 4, characterized in that: The first positioning unit body has a first protrusion protruding from one side towards the second fixing block to form a first protrusion, and the second positioning unit body has a second protrusion protruding from one side towards the second fixing block to form a second protrusion. The first protrusion and the second protrusion are perpendicular to each other, and the two adjacent edges of the second fixing block form forming cavities with the first protrusion and the second protrusion, respectively. The first positioning unit is provided with a first limiting surface, and the second positioning unit is provided with a third limiting surface. Step S1 further includes: one side of a sealing strip abutting against the first limiting surface inside the first positioning cavity and formed on one side wall of the first positioning unit body, and the other side of a sealing strip abutting against the first positioning cavity and formed on one side wall of the second fixing block. On the second limiting surface; one side of the other sealing strip abuts against the third limiting surface inside the second positioning cavity and formed on one side wall of the second positioning unit body, and the other side of the other sealing strip abuts against the fourth limiting surface inside the second positioning cavity and formed on the other side wall of the second fixing block; in step S2, after the upper template and the lower template are closed, a sealing strip located at the bottom of the upper template and whose first limiting protrusion, together with the first limiting surface and the second limiting surface, is limited to the first positioning cavity, and another sealing strip located at the bottom of the upper template and perpendicular to the first limiting protrusion, together with the third limiting surface, the fourth limiting surface, and the second step portion, is limited to the second positioning cavity.

6. The method for forming corner joints of sealing strips based on injection molds according to claim 5, characterized in that: In step S1, a first limiting body is provided on the first limiting surface, protruding from the first limiting surface into the first positioning cavity. There is one or more first limiting bodies. The first limiting body extends from the entrance of the first positioning cavity along the length direction of the first positioning unit towards the end near the first step. A gap is formed between the first limiting body and the first step. A first guide surface is formed at the end of the first limiting body near the entrance of the first positioning cavity.

7. The method for forming corner joints of sealing strips based on injection molds according to claim 5, characterized in that: In step S1, the middle position of the second limiting surface is recessed along the length direction of the second fixing block to form a first recessed portion, the surface of the first recessed portion forms a first recessed curved surface, one end of the second limiting surface extends to the bottom of the first positioning cavity, and the other end of the second limiting surface extends to the first limiting curved surface.

8. The method for forming corner joints of sealing strips based on injection molds according to claim 5, characterized in that: In step S1, a second limiting body is provided on the third limiting surface, protruding from the third limiting surface into the second positioning cavity. There is one or more second limiting bodies. The second limiting body extends from the entrance of the second positioning cavity along the length direction of the second positioning unit towards the end near the second step. A gap is formed between the second limiting body and the second step. A second guide surface is formed at the end of the second limiting body near the entrance of the second positioning cavity.

9. A method for forming corner joints of sealing strips based on injection molds according to claim 5, characterized in that: In step S1, the middle position of the fourth limiting surface is recessed along the width direction of the second fixing block to form a second recessed portion, and the surface of the second recessed portion forms a second recessed curved surface. One end of the fourth limiting surface extends to the bottom of the second positioning cavity, and the other end of the fourth limiting surface extends to the second limiting curved surface.

10. A method for forming corner joints of sealing strips based on injection molds according to claim 1, characterized in that: The injection molding equipment also includes a material storage device disposed on the upper mold base, an injection molding device disposed above the material storage device, an injection mold located between the upper mold base and the lower mold base, and a first drive assembly for driving the upper mold base. The first drive assembly is provided in four parts. The first drive assembly passes through the lower mold base and is connected to the upper mold base. Two first drive assemblies are respectively disposed at both ends of the base, and the distance between the two first drive assemblies is greater than the length of the base. The other two first drive assemblies are disposed on the side of the base away from the entrance of the second positioning cavity, and the distance between the other two first drive assemblies is less than the length of the lower mold plate.

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