Injection mold and injection molding method thereof

Abstract

The invention discloses an injection mold and an injection molding method thereof, and relates to the field of injection molds, the injection mold comprises a fixed mold and a movable mold, the injection mold further comprises a mold core, the mold core is fixedly installed on one side of the movable mold, an annular groove is formed in the end, close to the movable mold, of the mold core, a rotating ring is arranged in the annular groove, a protruding part is arranged on the surface of the rotating ring, and the protruding part comprises a protruding part; the protruding parts are located in the annular grooves, the side faces, away from the rotating ring, of the protruding parts are flush with the outer side face of the mold core, a gap is formed between every two adjacent protruding parts, a pit is formed between every two adjacent protruding parts, and during mold drawing, one protruding part rotates to any pit; according to the injection mold and the injection molding method thereof, before the push-out mechanism pushes the product to move in the axial direction of the mold core, the injection product is preliminarily separated from the surface of the mold core, the contact area between the injection product and the mold core is reduced, the resistance of the injection product during initial movement is reduced, and the probability of damage to the inner surface of the injection product during demolding is reduced.

Description

Technical Field

[0001] The invention relates to injection mold technology, in particular to an injection mold and an injection molding method thereof. Background Art

[0002] Injection molding is a common product molding method, which is to obtain a product of a desired shape by injecting a molten material into a molding mold. In the process of injection molding, a certain draft angle is generally required. For products without a draft angle, it is difficult to demold, which is easy to cause damage to the inner surface of the product. In the Chinese invention patent with publication number CN110802803A, a molding mold for demolding a resin hollow body (straight tube portion) without a draft angle is disclosed, which is formed by forming a groove portion recessed radially inwardly at the end of the first axial side throughout the entire circumference of the straight cylindrical portion, forming a convex strip portion in the groove portion, and climbing up the outer circumferential surface of the core portion of the mold core during demolding, and forming a gap between the inner circumferential surface of the resin hollow body and the outer circumferential surface of the core portion throughout the entire length of the resin hollow body, which is equivalent to forming a draft angle, thereby reducing damage during demolding;

[0003] However, since a certain pushing distance is required for the convex strip to move out of the groove to form a gap, and the resin and other raw materials will stick to the surface of the core after solidification and shrinkage, the initial stage of the pushing action will encounter greater resistance. Forced pushing will still have a high probability of causing damage to the inner surface of the product. Summary of the invention

[0004] The object of the present invention is to provide an injection mold and an injection molding method thereof to solve the above-mentioned deficiencies in the prior art.

[0005] In order to achieve the above object, the present invention provides the following technical solution: an injection mold, comprising a fixed mold and a movable mold, and further comprising:

[0006] The mold core is fixedly mounted on one side of the movable mold. An annular groove is provided at one end of the mold core close to the movable mold. A rotating ring is provided in the annular groove. A convex portion is provided on the surface of the rotating ring. The convex portion includes a plurality of convex portions distributed in an annular array and inclined on both sides. The convex portion is located in the annular groove. The side of the convex portion away from the rotating ring is flush with the outer side of the mold core. There is a gap between two adjacent convex portions to form a depression.

[0007] The swivel can rotate relative to the mold core around the central axis of the mold core, and when demolding, one of the protrusions rotates to any one of the recesses, and the swivel is connected to a driving mechanism for driving it to rotate.

[0008] Furthermore, the driving mechanism includes an annular rack arranged on the circumferential side of the rotating ring, and a gear meshingly connected to the annular rack, a first rotating shaft is fixedly connected to the middle of the gear, and the first rotating shaft is connected to a driving member for driving it to rotate.

[0009] Furthermore, the raised portion is composed of a raised portion a and a raised portion b, wherein the raised portion a is fixedly mounted on the rotating ring, and the raised portion b is movably mounted on the rotating ring and can move relative to the rotating ring along its radial direction.

[0010] Furthermore, the raised portion consists of a raised portion b and at least one raised portion a.

[0011] Furthermore, there are at least two protrusions a, and the protrusions a are close to each other or far away from each other.

[0012] Furthermore, the injection mold further comprises a starting component for controlling the contraction and extension of the protrusion b.

[0013] Furthermore, the starting component includes an air bag arranged in the swivel.

[0014] Furthermore, the swivel consists of a first ring body and a second ring body, the second ring body is rotatably installed inside the first ring body, a stepped groove is opened in the second ring body, and a push rod is fixedly connected to the side of the protrusion b close to the second ring body, and one end of the push rod abuts against the corresponding stepped groove.

[0015] An injection molding method for molding an injection molded product without a draft angle is applicable to the injection mold as described above, and specifically comprises the following steps:

[0016] S1, injecting molten raw materials into the injection mold, and obtaining an injection molded product to be demoulded after molding;

[0017] S2, the first demoulding stage: the movable mold and the fixed mold are separated;

[0018] S3, second demoulding stage: the rotating ring rotates to rotate the raised part to the recessed part, and pushes the raised part formed at the end of the injection molded product out of the recessed part;

[0019] S4, the third demoulding stage: the injection molded product is pushed out along the axial direction of the mold core and away from the movable mold to complete the demoulding;

[0020] Wherein, the step S2 also includes:

[0021] S201, the driving mechanism drives the rotating ring to rotate in the reverse direction first;

[0022] S202, the driving mechanism drives the rotating ring to rotate in the forward direction, and the raised portion moves to the recessed portion to complete the second demoulding stage.

[0023] Compared with the prior art, the injection mold and the injection molding method provided by the present invention have the following beneficial effects:

[0024] The injection mold and the injection molding method thereof enable a certain gap to be formed between the inner surface of the product and the mold core, and the gap is formed before the product moves axially along the mold core. Before the ejection mechanism pushes the product to move axially along the mold core, the injection molded product and the surface of the mold core have been initially separated, the contact area between the two is reduced, the resistance of the injection molded product during initial movement is reduced, and the probability of damage to the inner surface of the injection molded product during demolding is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0026] Figure 1 A schematic diagram of a partial structure of a cross-sectional view of an injection mold provided by an embodiment of the present invention;

[0027] Figure 2 A schematic diagram of a local structure of a mold core provided by an embodiment of the present invention;

[0028] Figure 3 A schematic diagram of the separation state of the mold core and the swivel provided in an embodiment of the present invention;

[0029] Figure 4 A schematic diagram of a convex portion before rotation in a radial cross-sectional view of a mold core provided by an embodiment of the present invention;

[0030] Figure 5 The embodiment of the present invention provides Figure 4 Schematic diagram of the raised part after rotation (one unit);

[0031] Figure 6 The embodiment of the present invention provides Figure 5 A schematic diagram of the local structure of the axial cross-sectional view of the mold core in the state;

[0032] Figure 7 A schematic diagram of the structure when one protrusion a is provided in an embodiment of the present invention;

[0033] Figure 8 A schematic diagram of a structure in which three protrusions a are provided and are spaced apart from each other, provided in an embodiment of the present invention;

[0034] Fig. 9 A schematic diagram of a structure in which three protrusions a are provided and close to each other according to an embodiment of the present invention;

[0035] Fig.10 A schematic diagram of a local structure when the protrusion b is extended when the airbag is provided in an embodiment of the present invention;

[0036] Fig.11 The embodiment of the present invention provides Fig.10 Schematic diagram of the local structure when the middle raised portion b is contracted;

[0037] Fig.12 A schematic diagram of the structure of a starting component in a stepped groove arrangement provided in an embodiment of the present invention;

[0038] Fig.13 The embodiment of the present invention provides Fig.12 Schematic diagram of the local structure (when the raised portion b is in contraction);

[0039] Fig.14 This is a schematic structural diagram of the embodiment of the present invention in which the protrusion b is extended higher than the groove and the protrusion moves to be demoulded.

[0040] Description of reference numerals:

[0041] 1. Fixed mold; 2. Moving mold; 3. Mold core; 31. Annular groove; 4. Rotating ring; 41. First ring body; 42. Second ring body; 5. Raised part; 51. Raised part; 511. Raised part a; 512. Raised part b; 52. Concave; 6. Driving mechanism; 61. Annular rack; 62. Gear; 63. First rotating shaft; 64. First cavity; 7. Starting component; 71. Airbag; 72. Second cavity; 73. Slide groove; 74. Step groove; 75. Ejector rod;

[0042] 101. ejection mechanism; 102. injection molded product; 103. protruding portion. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0044] For examples, see Figure 1 - Fig.14 , an injection mold, comprising a fixed mold 1 and a movable mold 2, and also comprising:

[0045] The mold core 3 is fixedly mounted on one side of the movable mold 2. An annular groove 31 is provided at one end of the mold core 3 close to the movable mold 2. A rotating ring 4 is provided in the annular groove 31. A convex portion 5 is provided on the surface of the rotating ring 4. The convex portion 5 includes a plurality of convex portions 51 distributed in an annular array and inclined on both sides. The convex portion 51 is located in the annular groove 31. The side of the convex portion 51 away from the rotating ring 4 is flush with the outer side of the mold core 3. There is a gap between two adjacent convex portions 51 to form a recess 52.

[0046] The swivel 4 can rotate relative to the mold core 3 around the central axis of the mold core 3, and when the mold is removed, one of the protrusions 51 rotates to any one of the recesses 52;

[0047] The swivel ring 4 is connected to a driving mechanism 6 for driving the swivel ring to rotate.

[0048] It should be noted that the injection mold is installed on an injection molding machine (not shown in the figure) and has the necessary components such as an ejection device, which is a prior art and will not be described in detail here. Based on the technical solution in this field, it will not cause trouble. For details, reference can be made to the prior art, such as an injection molding mold, an injection molding system and an injection molding method disclosed in the Chinese invention patent with publication number CN110802803A;

[0049] like Figure 1 The cross-sectional view of the injection mold shown (the specific structure of the ejection device and other components are omitted) is mainly divided into three stages when the injection molding is completed and the demolding process begins, namely the first demolding stage, the second demolding stage and the third demolding stage, wherein the second demolding stage is used to form a draft angle, and the third demolding stage is used to move the injection molded product 102 from the mold core 3 for demolding;

[0050] Specific:

[0051] In the first demoulding stage, after the injection molding is completed, the movable mold 2 moves to separate from the fixed mold 1, and the outer surface of the molded product 102 is demoulded from the fixed mold 1. At this time, the molded product 102 will remain on the mold core 3, and since there is no draft angle, the ejection mechanism 101 does not work temporarily. When the movable mold 2 moves to the position after the mold is opened or in the process of the movable mold 2 moving to the position after the opening, the second demoulding stage is entered;

[0052] It should be noted that, due to the presence of the annular groove 31 and the convex portion 5, after the injection molding is completed, the inner surface of the end of the injection molded product 102 close to the movable mold 2 will be formed with a convex portion 103 (see Figure 6 As shown, as a demonstration of forming a similar draft angle, the cross-sectional structure of the swivel and other structures is omitted. For details, please refer to Figure 1 ), the protruding portion 103 is formed at the concave portion 52 between two adjacent protruding portions 51, and after molding, the protruding portion 103 of the injection molded product 102 is staggered with the protruding portion 5, and does not affect the specifications of the effective portion of the injection molded product 102;

[0053] In the second demoulding stage, the rotating ring 4 is driven by the driving mechanism 6 to rotate, so that the protruding portion 5 rotates to the original recess 52. At this time, the protruding portion 5 rotates and pushes the protruding portion 103 of the injection molded product 102 to expand outward through the inclined portions on both sides thereof. The protruding portion 103 of the injection molded product 102 abuts against the surface of the protruding portion 5, so that the diameter of the opening of the injection molded product 102 close to the movable mold 2 is expanded. At the same time, the end surface of the protruding portion 5 will also serve as a slideway for the protruding portion 103 to slide. That is to say, after the protruding portion 5 rotates to the original recess 52, on the one hand, it acts on the protruding portion 103 of the injection molded product 102 during molding, so that the protruding portion 103 moves to the outside of the annular groove 31 (see Figure 6 As shown), at this time, a certain gap will be formed between the inner surface of the injection molded product 102 and the surface of the mold core 3, thereby initially separating and forming a draft state similar to the draft angle. On the other hand, the protruding portion 5 and the surface of the mold core 3 form a slideway for the protruding portion 103 to move away from the movable mold 2;

[0054] In the third demolding stage, the injection molded product 102 is driven to be demolded from the mold core 3 with the cooperation of the ejection mechanism 101. During the movement of the injection molded product 102, the protruding portion 103 of the injection molded product 102 first slides along the end surface of the protruding portion 5 to the surface of the mold core 3, and then slides along the surface of the mold core 3 until the product is separated from the mold core 3. It should be noted that in the entire third demolding stage, the injection molded product 102 will be demolded in a state where one end is expanded, thereby forming a demolding situation similar to that with a draft angle;

[0055] Therefore, for products that do not have a draft angle (such as a hollow cylindrical body), when demolding is performed in the above manner, the inner surface of the product will be able to produce a certain gap with the core 3, and the gap is generated before the product moves axially along the core 3. Compared with the injection molded product 102, which first moves a certain distance under the action of the ejection mechanism 101 and gradually generates a gap at this distance, before the ejection mechanism 101 pushes the product to move axially along the core 3, the injection molded product 102 and the surface of the core 3 have been initially separated, the contact area between the two is reduced, and the resistance of the injection molded product 102 during the initial movement is reduced, which further reduces the probability of damage to the inner surface of the injection molded product 102 during demolding.

[0056] In one embodiment of the present invention, a specific example of a driving mechanism 6 is provided, which includes an annular rack 61 arranged on the circumference of the rotating ring 4, and a gear 62 meshing with the annular rack 61, a first rotating shaft 63 is fixedly connected to the middle of the gear 62, and the first rotating shaft 63 is connected to a driving member for driving the first rotating shaft 63 to rotate, and the rotation of the first rotating shaft 63 drives the gear 62 to rotate and drives the rotating ring 4 to rotate;

[0057] For details, please refer to Figure 2 and Figure 3, a first cavity 64 for accommodating an annular rack 61 and a gear 62 is provided in the mold core 3, a first rotating shaft 63 penetrates the mold core 3 and is rotatably connected to the inner wall of the mold core 3, and when the mold core 3 is assembled to the movable mold 2, one end of the first rotating shaft 63 extends to the outside of one side of the movable mold 2 and is connected to the driving member; it should be noted that, in order to facilitate the assembly and processing of the swivel 4 and the driving mechanism 6, the mold core 3 is composed of two parts, which are detachably connected by bolts, and the annular groove 31 and the first cavity 64 are formed after the connection;

[0058] In order to rotate the raised portion 51 of the raised part 5 to the original recess 52, the rotating ring 4 is driven by the driving mechanism 6 to rotate at least one unit, wherein one unit is the angle at which the raised portion 51 rotates to the closest original recess 52 (or, one unit is the minimum angle at which the raised portion 51 rotates to the original recess 52). Figure 4 and Figure 5 α in the figure;

[0059] In the second demoulding stage, the angle of the rotating ring 4 before and after rotation is at least an integral multiple of a unit, so that the raised portion 51 of the raised part 5 is located at the original recess 52 after the rotating ring 4 stops, completing the second demoulding stage;

[0060] Generally, the swivel 4 only needs to rotate one unit. However, for some injection molded products 102 with high brittleness, rotating only one unit can easily lead to a large change in the force before and after the expansion of the end of the injection molded product 102, so that cracks are easily generated in the expanded part of the end of the injection molded product 102 when entering the third demolding stage after expansion. One end of the crack extends to the effective area of ​​the injection molded product 102, which will cause product damage. Based on this, the risk of damage under this factor can be reduced by rotating multiple units. When rotating multiple units, the raised part 5 and the protruding part 103 of the injection molded product 102 are repeatedly staggered. During the rotation of the swivel 4, the duration of the injection molded product 102 reaching the expanded state is reduced, which is conducive to reducing the probability of cracks. In short, by rotating multiple units, the expansion of the end of the injection molded product 102 will act in a multiple expansion manner. Compared with the method of rotating one unit, the internal stress is evenly dispersed after expansion, and it is also conducive to the uniform resetting of the expanded part after demolding. In addition, it is foreseeable that the process of rotating multiple units will also be conducive to the gradual separation of the inner surface of the injection molded product 102 and the surface of the core 3.

[0061] It should be noted that the original depression 52 refers to the depression 52 formed between adjacent protrusions before the rotating ring 4 rotates.

[0062] In one embodiment of the present invention, the raised portion 5 is composed of a raised portion a511 and a raised portion b512, wherein the raised portion a511 is fixedly mounted on the rotating ring 4, and the raised portion b512 is movably mounted on the rotating ring 4 and can move relative to the rotating ring 4 along its radial direction;

[0063] In one embodiment of the present invention, the raised portion 5 is composed of a raised portion b512 and at least one raised portion a511;

[0064] It should be understood that when the raised portion 5 is entirely composed of the raised portion a511, it is the above-mentioned raised portion 51;

[0065] In one embodiment of the present invention, taking the number of protrusions a511 as one as an example, the rest of the protrusions 5 are all protrusions b512, such as Figure 7 As shown;

[0066] In the second demoulding stage, before the driving swivel 4 of the driving mechanism 6 rotates, each protrusion b512 moves to the axial direction of the swivel 4 to a contracted state, and then the driving mechanism 6 drives the swivel 4 to rotate. During the rotation, only the protrusion a511 can push the protruding portion 103 of the injection molded product 102 out of the annular groove 31, while the protrusion b512 does not push the protruding portion 103 or does not push the protruding portion 103 out of the annular groove 31 when pushing it. It depends on the distance that the protrusion b512 can move relative to the swivel 4 in its radial direction. When the protrusion b512 shrinks to a maximum diameter that is smaller than the minimum diameter of the protruding portion 103, the protrusion b512 will not push the protruding portion 103 of the injection molded product 102 in the process of following the rotation of the swivel 4. When the protrusion b512 shrinks to a maximum diameter that is not less than the minimum diameter of the protruding portion 103, at least part of the protrusion b512 will push the protruding portion 103 of the injection molded product 102 to expand.

[0067] Therefore, in the second demolding stage, the opening diameter of the end of the injection molded product 102 is expanded in a gradually expanding manner during the rotation of the rotating ring 4. Specifically, the rotation of the protrusion a511 will push the protruding portion 103 of the injection molded product 102 in contact with it on its moving path to move out of the annular groove 31, and the protruding portion 103 not in contact with the protrusion a511 will not move out of the annular groove 31 (the opening portion of the injection molded product 102 on the side close to the movable mold 2 is in an incomplete expansion state where the diameter has not yet expanded to the maximum state). state), considering that when the opening of the injection molded product 102 close to the movable mold 2 is expanded, it is also necessary to overcome the adhesion between the product and the surface of the mold core 3 after solidification, the above-mentioned protrusion a511 and the protrusion b512 are combined, and the rotation of the protrusion a511 is used to pre-expand the opening of the injection molded product 102 to the required diameter position and separate it from the surface of the mold core 3. At the same time, each protrusion b512 is in a state of contraction toward the axis of the swivel 4 to reduce the probability of cracks at the opening of the injection molded product 102 when the protrusion a511 moves;

[0068] It should be noted that when a protrusion a511 is set, the swivel 4 rotates at least one circle, and finally each protrusion b512 moves away from the axis of the swivel 4 to an extended state. At this time, it can be regarded as the protrusion a511, that is, the rotation of the swivel 4 at this time is equivalent to the action of the protrusion 5 composed entirely of the protrusion a511, thereby completing the second demolding stage.

[0069] In one embodiment of the present invention, there are at least two protrusions a511, and the protrusions a511 are close to or far away from each other. For example, three protrusions a511 are provided. Fig. 9 The close proximity and Figure 8 In the state of being far away from each other as shown, compared with setting one protrusion a511, the swivel 4 only needs to rotate at least one-third of a circle. It is worth mentioning that although it reduces the minimum angle required for the swivel 4 to rotate, it does not mean that the more protrusions a511 the better. Under the premise that the protrusion b512 is needed, the more protrusions a511 the more the probability of cracks at the opening of the injection molded product 102 is.

[0070] Similarly, similar to the setting of the recess 52 formed between two adjacent protrusions 51, the deeper the depth of the recess 52 is (from the perspective of mold processing, the depth can be selected), the larger the similar draft angle is formed, and the more conducive to demolding. However, this also requires the opening expansion diameter of the injection molded product 102 to become larger, which increases the risk of cracks and the difficulty of restoring the effective part of the injection molded product 102 to a straight cylindrical shape after demolding. Therefore, the recess 52 is generally not the deeper the better. Generally, it is necessary to consider multiple factors such as injection molding material, wall thickness and diameter. It should be noted that for the convenience of illustration, the illustration size of the raised part 5 and the corresponding structure is enlarged in the accompanying drawings.

[0071] In one embodiment of the present invention, a starting component 7 is provided to control the contraction and extension of the protrusion b512;

[0072] In one embodiment of the present invention, the starting component 7 includes an air bag 71 disposed in the rotating ring 4. Fig.10 and Fig.11 As shown, specifically, a second cavity 72 for accommodating the airbag 71 is provided in the swivel 4, and a slide groove 73 for each protrusion b512 to slide is provided on the swivel 4. One end of the protrusion b512 close to the axis of the swivel 4 abuts against the surface of the airbag 71. When the airbag 71 expands, the protrusions b512 are driven to extend, and when the airbag 71 contracts, the protrusions b512 can contract. The airbag 71 is connected to an external gas source through a gas channel passing through the swivel 4 and a valve controller to control the expansion and contraction of the airbag 71. For the contraction of the airbag 71, it is only necessary that the gas in the airbag 71 can be discharged freely (the valve remains open).

[0073] In one embodiment of the present invention, another specific example of the starting component 7 is provided. Specifically, the rotating ring 4 is composed of a first ring body 41 and a second ring body 42. The first ring body 41 is connected to the raised portion 5, and the second ring body 42 is rotatably mounted on the inner side of the first ring body 41. The annular rack 61 is fixedly connected to the inner side of the second ring body 42. A stepped groove 74 is provided in the second ring body 42. A push rod 75 is fixedly connected to one side of the raised portion b512 close to the second ring body 42, and one end of the push rod 75 abuts against the corresponding stepped groove 74. Fig.12 and Fig.13 As shown, the contraction and expansion of the protrusion b512 are achieved by driving the second ring body 42 to rotate. More specifically, when the second ring body 42 rotates forward, the end of the push rod 75 moves into the shallower stepped groove 74, so that the protrusion b512 extends out. When the second ring body 42 rotates reversely, the end of the push rod 75 moves into the deeper stepped groove 74, so that the protrusion b512 can be contracted. It should be noted that the depth of the deeper groove in the stepped groove 74 determines the maximum distance that the protrusion b512 can be contracted.

[0074] In one embodiment of the present invention, when the protrusion b512 is used, the protrusion b512 can be higher than the groove after being extended, such as Fig.14 As shown, the protruding portion 103 can be smoothly moved for demoulding.

[0075] In one embodiment of the present invention, the driving member is an electric motor, a pneumatic motor or a hydraulic motor, and the output end of the electric motor, the output end of the hydraulic motor or the output end of the pneumatic motor is connected to the first rotating shaft 63; the first rotating shaft 63 is driven by the driving member to rotate to drive the gear 62 to rotate, and the rotation of the gear 62 drives the rotating ring 4 to rotate.

[0076] An injection molding method for molding an injection molded product 102 without a draft angle comprises the following steps:

[0077] S1, injecting molten raw materials into the injection mold, and obtaining an injection molded product 102 to be demoulded after molding;

[0078] S2, first demoulding stage: the movable mold 2 is separated from the fixed mold 1;

[0079] S3, second demoulding stage: the rotating ring 4 rotates to rotate the protruding portion 5 to the concave portion 52, and pushes the protruding portion 103 formed at the end of the injection molded product 102 out of the concave portion 52;

[0080] S4, the third demoulding stage: the injection molded product 102 is pushed out along the axial direction of the mold core 3 and away from the movable mold 2 to complete the demoulding.

[0081] For the second demoulding stage in S2, when the protrusion b512 is used, the corresponding starting components 7 are different, and the step groove 74 is set as an example, specifically:

[0082] S201, the driving mechanism 6 drives the rotating ring 4 to rotate in the opposite direction first, so as to shrink each protrusion b512, and at least one protrusion a511 makes the injection molded product 102 expand in advance;

[0083] S202, the driving mechanism 6 drives the rotating ring 4 to rotate in the forward direction, so as to extend each protrusion b512, and the protrusion 5 moves to the original recess 52 to push the protrusion 103 formed at the end of the injection molded product 102 out of the recess 52, completing the second demolding stage.

[0084] The above only describes some exemplary embodiments of the present invention by way of illustration. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the present invention.

Claims

1. An injection mold, comprising a fixed mold and a movable mold, characterized in that: Also includes: The mold core is fixedly mounted on one side of the movable mold. An annular groove is provided at one end of the mold core close to the movable mold. A rotating ring is provided in the annular groove. A convex portion is provided on the surface of the rotating ring. The convex portion includes a plurality of convex portions distributed in an annular array and inclined on both sides. The convex portion is located in the annular groove. The side of the convex portion away from the rotating ring is flush with the outer side of the mold core. There is a gap between two adjacent convex portions to form a depression. The swivel can rotate relative to the mold core around the central axis of the mold core, and when the mold is demoulded, one of the protrusions rotates to any one of the recesses; The swivel is connected to a driving mechanism for driving the swivel to rotate.

2. An injection mold according to claim 1, characterized in that: The driving mechanism includes an annular rack arranged on the circumferential side of the rotating ring, and a gear meshingly connected to the annular rack. A first rotating shaft is fixedly connected to the middle of the gear, and the first rotating shaft is connected to a driving member for driving the rotation thereof.

3. An injection mold according to claim 1, characterized in that: The convex part is composed of a convex part a and a convex part b. The convex part a is fixedly mounted on the rotating ring, and the convex part b is movably mounted on the rotating ring and can move relative to the rotating ring along its radial direction.

4. An injection mold according to claim 3, characterized in that: The raised portion consists of a raised portion b and at least one raised portion a.

5. An injection mold according to claim 4, characterized in that: There are at least two protrusions a, and the protrusions a are close to each other or far away from each other.

6. The injection mold according to claim 3, characterized in that: It also includes a starting component for controlling the contraction and extension of the protrusion b.

7. An injection mold according to claim 6, characterized in that: The starting component includes an air bag arranged in the swivel.

8. The injection mold according to claim 6, characterized in that: The swivel consists of a first ring body and a second ring body. The second ring body is rotatably mounted inside the first ring body. A stepped groove is provided inside the second ring body. A push rod is fixedly connected to one side of the raised portion b close to the second ring body, and one end of the push rod abuts against the corresponding stepped groove.

9. An injection molding method for molding an injection molded product without a draft angle, characterized in that: The method is applicable to the injection mold according to any one of claims 1 to 8, and specifically comprises the following steps: S1, injecting molten raw materials into the injection mold, and obtaining an injection molded product to be demoulded after molding; S2, the first demoulding stage: the movable mold and the fixed mold are separated; S3, second demoulding stage: the rotating ring rotates to rotate the raised part to the recessed part, and pushes the raised part formed at the end of the injection molded product out of the recessed part; S4, the third demoulding stage: the injection molded product is pushed out along the axial direction of the mold core and away from the movable mold to complete the demoulding.

10. The injection molding method according to claim 9, characterized in that: The step S2 also includes: S201, the driving mechanism drives the rotating ring to rotate in the reverse direction first; S202, the driving mechanism drives the rotating ring to rotate in the forward direction, and the raised portion moves to the recessed portion to complete the second demoulding stage.

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