Demolding equipment for injection molding gear
Through the injection molding gear demolding equipment that moves in concert with the push cylinder and the core rod, the gear demolding damage and difficulties under the small contact area are solved, and efficient and lossless injection molding is achieved, which improves production efficiency and product quality.
Patent Information
- Application Number
- CN202510713044.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-07-11
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
Existing injection molding gear demolding equipment can easily lead to damage to the gear surface or difficulty in demolding under small contact area, especially when the central shaft hole accounts for a large proportion, it is difficult to effectively demold the traditional thimble or push pipe method.
A mold release device that moves in concert with the push cylinder and the core rod is adopted. The guide grooves on the inner wall of the push cylinder and the guide blocks on the push rod are formed to control the overall ejection and separation of the injection molded parts, avoiding surface damage caused by point contact. The injection molded parts and push cylinder are separated by the strong clamping force of the core rod and the gear, and the mold release is completed by combining the coordination of the limiting parts and the rotating parts.
Ensure the smoothness and integrity of the mold release process of injection molded parts, improve production efficiency, reduce waste rate, and avoid surface damage caused by traditional methods.
Smart Images
Figure CN120287516A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to injection mold technology, and more particularly to a demolding device for injection-molded gears. Background Art
[0002] After plastic gears are injection-molded, they are usually demolded by using ejector pins. This requires the injection-molded gears to have a certain area for the ejector pins to contact. If the contact area is small, using the ejector pin method will result in excessive extrusion force when the ejector pin pushes the gear injection-molded part, which is likely to damage the surface of the gear injection-molded part. This problem is more likely to occur especially when the adhesion force between the gear injection-molded part and the core and cavity is large. For example, Figure 5 For the plastic gear shown, the space of its central shaft hole accounts for a relatively large proportion, and the contactable part of the gear part is less. The diameter of the core used to form the shaft hole in the mold is relatively large. After injection molding, the shrinkage of the gear injection-molded part will also cause a large holding force between it and the core surface. If the ejector pin method is still used, first, there is no large contactable position, and second, the space for setting the ejector pin is limited, and the diameter of the ejector pin can only be set small, resulting in the ejector pin being easily inserted into the injection-molded part when driving the injection-molded part to demold, leading to defective products and affecting the demolding effect. Summary of the Invention
[0003] The purpose of the present invention is to provide a demolding device for injection-molded gears to solve the above deficiencies in the prior art.
[0004] To achieve the above purpose, the present invention provides the following technical solution: A demolding device for injection-molded gears, including a moving mold and a fixed mold. A cavity base is installed in the fixed mold, and a core rod is arranged in the cavity base. It further includes:
[0005] A pushing device, which includes a push rod and a push cylinder. The push rod is coaxially and rotatably connected to the bottom of the core rod. The push cylinder is sleeved on the surfaces of the core rod and the push rod, and the push cylinder can move axially in the cavity base. The push rod is connected to a moving member for driving it to move along its own axis, and a rotating member for driving it to rotate around its own axis;
[0006] Guide grooves are formed on the inner wall of the push cylinder. The guide grooves include two axial grooves and a ring groove. The two ends of the ring groove are connected to the two axial grooves. A guide block is arranged on one side of the push rod, and the guide block can move along the guide grooves;
[0007] The pushing device further includes a limiting member for limiting the axial movement of the push cylinder.
[0008] Further, the top of the push cylinder is adapted to the bottom of the injection-molded part.
[0009] Further, the length of the upper axial groove is 1 mm to 5 mm.
[0010] Further, the length of the axial groove located below is greater than the distance that the top of the core rod moves out of the bottom of the injection molded part.
[0011] Further, the ejector pin and the core rod are connected by a detachable rotating assembly.
[0012] Further, the rotating assembly includes two clamps. The two clamps are detachably fixed to the bottom of the core rod through fastening bolts, and a rotating cavity for connecting the ejector pin is formed in the middle of the two clamps. The top of the ejector pin is clamped in the rotating cavity and can rotate in the rotating cavity.
[0013] Further, the moving part includes a moving plate and a driving part A for driving the moving plate to move axially along the ejector pin.
[0014] Further, the rotating part includes a rotating rod seat. The rotating rod seat is rotatably connected to the moving plate. One end of the rotating rod seat is connected to the bottom of the ejector pin and is coaxial with it. A rotating rod is slidably connected to the inner wall of the rotating rod seat, and the rotating rod is connected to the output end of the motor.
[0015] Further, the limiting part includes a limiting groove opened on the peripheral side of the push cylinder and a movable cavity opened in the cavity base. A limiting pin is slidably installed in the movable cavity. A spring is installed on one side of the limiting pin, and the elastic force of the spring acts on the limiting pin to make it have a moving tendency to approach the push cylinder. The limiting part further includes a reset part for driving the limiting pin to move into the movable cavity.
[0016] Further, the push cylinder can rotate around its axis in the cavity base.
[0017] Compared with the prior art, a demolding device for injection molded gears provided by the present invention has the following beneficial effects:
[0018] For the demolding device of the injection molded gear, through the coordinated movement of the push cylinder and the core rod, the problem of demolding damage of gears with a small contact area is solved. The guide groove opened on the inner wall of the push cylinder forms motion control with the guide block on the ejector pin through two axial grooves and a ring groove. When the guide block is located in the ring groove, the movement of the ejector pin drives the synchronous movement of the push cylinder to realize the overall ejection of the injection molded part from the cavity base. After ejection, the limiting part locks the push cylinder, and the guide block slides into the upper axial groove. The ejector pin continues to move upward, and the strong clamping force between the core rod and the gear is used to separate the injection molded part from the push cylinder. Subsequently, the ejector pin moves downward to drive the core rod to withdraw. When the guide block slides into the lower axial groove, the push cylinder is fixed to block the injection molded part from falling, completing the withdrawal of the core rod. For gear injection molded parts with a large central shaft hole ratio and a small supportable area for the tooth part, traditional ejector pin demolding is likely to cause surface damage or insertion into the interior of the injection molded part.
[0019] By using a push tube to replace the ejector pin, the way of full contact at the local position of the bottom of the injection molded part is used to replace the point contact, dispersing the demolding stress, avoiding surface damage of the injection molded part caused by the ejector pin method, and the problem of difficult demolding of the general push tube pushing the injection molded part alone, so as to ensure the smoothness and integrity of the demolding process of the injection molded part, improve production efficiency and product quality, and reduce the scrap rate. Brief Description of the Drawings
[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings.
[0021] Figure 1 It is a schematic diagram of a partial longitudinal section structure of the moving mold in the open mold state provided by the embodiment of the present invention;
[0022] Figure 2 It is a schematic diagram of a partial longitudinal section structure of the cavity base and the ejection device provided by the embodiment of the present invention;
[0023] Figure 3 Provided by the embodiment of the present invention Figure 2 The enlarged view of part A in
[0024] Figure 4 It is a schematic diagram of the partial structure of the reset member provided by the embodiment of the present invention;
[0025] Figure 5 It is a schematic diagram of the separated state of the cavity base, the core rod, the push tube and the injection molded part provided by the embodiment of the present invention;
[0026] Figure 6 It is a schematic diagram of the structure of the rotating assembly provided by the embodiment of the present invention;
[0027] Figure 7 It is a schematic diagram of the guide groove structure (partial view of the expanded state of the push tube) provided by the embodiment of the present invention;
[0028] Figure 8 It is a schematic diagram of the helical gear injection molded part structure provided by the embodiment of the present invention;
[0029] Figure 9 It is a schematic diagram of the second guide groove structure provided by the embodiment of the present invention;
[0030] Figure 10 It is a schematic diagram of the third guide groove structure provided by the embodiment of the present invention;
[0031] Figure 11 It is a schematic diagram of the process when the injection molded part is demolded provided by the embodiment of the present invention.
[0032] Description of the reference numerals in the drawings:
[0033] 1. Moving mold; 2. Fixed mold; 3. Cavity base; 4. Core rod; 5. Ejection device; 51. Push rod; 52. Push cylinder; 521. Protruding part; 53. Moving part; 531. Moving plate; 532. A driving part; 54. Rotating part; 541. Rotating rod seat; 542. Rotating rod; 543. Motor; 55. Guide groove; 551. Axial groove; 552. Ring groove; 56. Guide block; 57. Limiting part; 571. Limiting groove; 572. Moving cavity; 573. Limiting pin; 574. Spring; 575. Reset part; 58. Rotating assembly; 581. Clamp; 582. Rotating cavity; 6. Injection molded part; 7. Helical gear. Detailed implementation mode
[0034] In order to enable those skilled in the art to better understand the technical solution of the present invention, generally, in the existing method, multiple ejector pins are usually set. First, core pulling is performed on the core, and then the injection molded part 6 is pushed out of the mold by the multiple ejector pins. The multiple ejector pins are used to disperse the force to avoid damaging the surface of the injection molded part 6; there are also existing methods similar to the technical solution of the present application, which realize demolding by setting a push tube or directly moving the core upward instead of using ejector pins. However, if the adhesion force between the core and the injection molded part 6 is less than the adhesion force or resistance between the injection molded part 6 and the cavity, it is difficult to directly demold. In the case of using a push tube, generally, after core pulling, the injection molded part 6 is ejected. However, for a gear as shown in Figure 5 , in the case where the space occupied by the central shaft hole of the gear is relatively large and the area of the supportable part at the end of the gear is relatively small, the method of directly pushing by the push tube is also likely to damage the end of the gear due to large resistance, affecting the product quality. The present invention will be further introduced in detail below with reference to the drawings.
[0035] Example, please refer to Figures 1 - 11 , a demolding device for an injection molded gear, including a moving mold 1 and a fixed mold 2. A cavity base 3 is installed in the fixed mold 2, and a core rod 4 is arranged in the cavity base 3. It further includes:
[0036] An ejection device 5, which includes a push rod 51 and a push cylinder 52. The push rod 51 is coaxially and rotatably connected to the bottom of the core rod 4. The push cylinder 52 is sleeved on the surfaces of the core rod 4 and the push rod 51, and the push cylinder 52 can move axially in the cavity base 3. The push rod 51 is connected to a moving part 53 for driving it to move along its own axis, and a rotating part 54 for driving it to rotate around its own axis;
[0037] A guide groove 55 is formed on the inner wall of the push cylinder 52. The guide groove 55 includes two axial grooves 551 and a ring groove 552. The two ends of the ring groove 552 are communicated with the two axial grooves 551. A guide block 56 is arranged on one side of the push rod 51, and the guide block 56 can move along the guide groove 55;
[0038] The ejecting device 5 further includes a limiting member 57 for restricting the axial movement of the push cylinder 52.
[0039] Please refer to Figure 7 (partial view in the unfolded state of the push cylinder 52). A part of the annular groove 552 in the guide groove 55 is located in the radial plane of the push rod 51. When the guide block 56 moves along the guide groove 55, it is driven by the moving member 53 to move in the two axial grooves 551 and is driven by the rotating member 54 to move in the annular groove 552. When the guide block 56 is located in the annular groove 552, when the moving member 53 drives the push rod 51 to move axially, the core rod 4 and the push cylinder 52 will move synchronously. When the guide block 56 moves in the vertical groove, the push cylinder 52 does not move under the restriction of the limiting member 57, and only the push rod 51 moves;
[0040] It should be noted that the push cylinder 52 forms the bottom part of the cavity in the mold. Refer to Figure 5 , and its function is basically the same as the way of using the ejector pin to eject the injection molded part 6 for demolding. The difference is that the top of the push cylinder 52 is adapted to the bottom of the injection molded part 6. When the supportable part is so small that it affects the ability to eject the injection molded part 6, a protruding part 521 (see Figure 5 ) that is at least partially adapted to the tooth opening of the injection molded part 6 (gear) can be provided on the circumferential side of the push cylinder 52.
[0041] Please refer to Figure 11 , and the demolding process (after the moving mold 1 is separated) after injection molding mainly includes the following stages:
[0042] Ejecting stage: The moving member 53 drives the push rod 51 and the push cylinder 52 to move synchronously, so that the core rod 4 and the push cylinder 52 move upward synchronously to eject the injection molded part 6 from the cavity base 3, and the demolding of the injection molded part 6 from the inner cavity of the cavity base 3 is completed. Among them, when the moving member 53 drives the push rod 51 to move, the guide block 56 is located in the annular groove 552 outside the upper axial groove 551, so that the push cylinder 52 is driven to move synchronously through the movement of the guide block 56. The state after ejection is shown in Figure 11 the second figure in the process direction in
[0043] First demolding stage: The limiting member 57 restricts the movement of the push cylinder 52 to keep it in the current position. Then, the rotating member 54 drives the push rod 51 to rotate so that the guide block 56 on it rotates to the bottom of the upper axial groove 551. Then, the moving member 53 drives the push rod 51 to move further upward by a certain distance, and the core rod 4 will drive the injection molded part 6 to move, so that the bottom of the injection molded part 6 is separated from the top of the push cylinder 52, and the preliminary demolding is completed;
[0044] It should be noted that the upward movement of the core rod 4 can separate the injection molded part 6 from the push cylinder 52 because the adhesion force (clamping force) between the injection molded part 6 and the core rod 4 is relatively large during the molding of the injection molded part 6, while the adhesion force between the push cylinder 52 that only contacts a partial position at the bottom of the injection molded part 6 and the injection molded part 6 is relatively small. Generally, the injection molded part 6 will be separated from the top of the push cylinder 52 during the upward movement of the core rod 4. If the separation fails or the core rod 4 separates first, it indicates that the injection molding of the injection molded part 6 has failed, such as insufficient injection volume during the injection of molten plastic, resulting in the injection molded part 6 not having the required gear injection molded part 6 after molding. This situation is a common problem during the production process and does not affect the progress of the first demolding stage. In this case, the waste material can be removed and injection molding can be carried out again.
[0045] In the second demolding stage, the moving part 53 drives the push rod 51 to move downward, thereby driving the core rod 4 to move downward. When the guide block 56 moves to the annular groove 552 part, the rotating part 54 drives the push rod 51 to rotate, so that the guide block 56 moves to the top position of the axial groove 551 located below. Then, the moving part 53 continues to drive the push rod 51 to move downward. During the downward movement of the push rod 51, the guide block 56 moves downward along the axial groove 551, and the core rod 4 moves downward synchronously. Since the push cylinder 52 is always in a state restricted by the limiting part 57, when the injection molded part 6 is driven by the core rod 4 to contact the top of the push cylinder 52 at its bottom, the push cylinder 52 will prevent the continued movement of the injection molded part 6. Under the continuous downward movement of the core rod 4, the core rod 4 will gradually be withdrawn from the injection molded part 6, and the injection molded part 6 will finally be completely separated from the core rod 4, completing the demolding.
[0046] After demolding, the injection molded part 6 will remain on the top of the push cylinder 52. At this time, the injection molded part 6 can be removed from the push cylinder 52 manually or by a manipulator for subsequent processing.
[0047] In the above demolding method, the injection molded part 6 can be smoothly separated from the cavity base 3 under the coordinated action of the core rod 4 and the push cylinder 52. Then, with the further cooperation of the ejection device, through the relative movement between the core rod 4 and the push cylinder 52, the complete demolding of the injection molded part 6 is completed. For the gear injection molded part 6 with a relatively large ratio of the axis to the axis hole, it can avoid the problem of surface damage to the injection molded part 6 caused by the thimble method and the difficulty of demolding the injection molded part 6 by a general push tube alone, thus ensuring the smoothness and integrity of the demolding process of the injection molded part 6, improving production efficiency and product quality, and reducing the scrap rate.
[0048] In one embodiment of the present invention, since the separation distance required during the separation of the injection molded part 6 from the top of the push cylinder 52 is relatively short, correspondingly, the length of the upper axial groove 551 in the guide groove 55 usually does not need to be too long. For the way that the injection molded part 6 and the bottom of the push cylinder 52 are in planar contact, generally, a length of 1 - 5 mm is sufficient. It should be understood that the 1 - 5 mm here is the distance that the guide block 56 can move upward after moving to the upper axial groove 551. For a gear injection molded part 6 as shown in Figure 5 , which has flange parts on both sides and is not in planar contact with the top of the push cylinder 52, the required separation distance affected by the flange parts needs to be considered. For the case where the height of the flange part is relatively high, the length of the axial groove 551 should be appropriately increased. For the case where the flange height is relatively short ( Figure 5 and Figure 11 shown), generally, a displacement of only 5 mm is required. As long as the initial demolding separation process is completed, the resistance to removing the subsequent injection molded part 6 is greatly reduced, and it can be easily removed manually or by a manipulator. Figure 7 In
[0049] , for the convenience of illustration, the length of the upper axial groove 551 is extended, and this should not be regarded as a limitation on its length or proportion.
[0050] It should be noted that an appropriate length of the guide groove 55 is beneficial to reducing the length of the push cylinder 52 and the dimensions of some structures in the ejection device 5, and optimizing the occupied space of the structure.
[0051] In one embodiment of the present invention, for the convenience of disassembling the push rod 51 and the core rod 4, the push rod 51 and the core rod 4 are connected by a detachable rotating assembly 58, as shown in Figure 6As shown in the figure, the rotating assembly 58 includes two symmetric semi-circular clamps 581. The two clamps 581 are detachably fixed to the bottom of the core rod 4 through fastening bolts. A rotating cavity 582 for connecting the push rod 51 is formed in the middle of the two clamps 581. The top of the push rod 51 is clamped in the rotating cavity 582 and can rotate in the rotating cavity 582. When the core rod 4 is damaged or needs to be replaced for other reasons, only the fastening bolts need to be loosened, and then the push rod 51 and the core rod 4 can be disassembled. When replacing, the rotating connection assembly can be reused. In addition, bearings can also be installed in the rotating cavity 582 to reduce the friction between the push rod 51 and the core rod 4 and improve the rotating flexibility. It should be understood that the two clamps 581 can also be installed on the top of the push rod 51, which is not limited in the present invention.
[0052] In an embodiment of the present invention, the moving member 53 includes a moving plate 531 and a driving member A 532 for driving the moving plate 531 to move along the axial direction of the push rod 51. The driving member A 532 is a cylinder or a hydraulic cylinder or an electric telescopic rod. The output end of the cylinder or the output end of the hydraulic cylinder or the output end of the electric telescopic rod is connected to the moving plate 531 to drive the moving plate 531 to move.
[0053] In an embodiment of the present invention, the rotating member 54 includes a rotating rod seat 541. The rotating rod seat 541 is rotatably connected to the moving plate 531. One end of the rotating rod seat 541 is connected to the bottom of the push rod 51 and is coaxial with it. A rotating rod 542 is slidably connected to the inner wall of the rotating rod seat 541. The rotating rod 542 is connected to the output end of the motor 543, and the rotating rod 542 is driven to rotate by the motor 543.
[0054] As Figure 1 shown, the specific principle process when the rotating member 54 and the moving member 53 work will not be specifically described here. It is common knowledge in the prior art. For the startup and shutdown processes during work, refer to the above-mentioned demoulding process.
[0055] In an embodiment of the present invention, the limiting member 57 includes a limiting groove 571 opened on the circumferential side of the push cylinder 52 and a movable cavity 572 opened in the cavity base 3. A limiting pin 573 is slidably installed in the movable cavity 572. A spring 574 is installed on one side of the limiting pin 573. The elastic force of the spring 574 acts on the limiting pin 573 to make it have a moving tendency to approach the push cylinder 52. The limiting member 57 further includes a reset member 575 for driving the limiting pin 573 to move into the movable cavity 572.
[0056] As shown in Figure 4 and Figure 11In the shown flow chart, when the pushing cylinder 52 moves to the required height, under the action of the spring 574, the limit pin 573 is pushed into the limit groove 571 to restrict the movement of the pushing cylinder 52. After demolding, the reset member 575 releases the restriction of the limit pin 573 on the pushing cylinder 52, enabling the pushing cylinder 52 to move downward for the next injection molding operation;
[0057] In an embodiment of the present invention, an example of the reset member 575 is provided. It is driven in a pneumatic manner. Specifically, the limit pin 573 seals and slides with the movable cavity 572. A gas passage communicating with an external air extraction assembly is provided on the side of the movable cavity 572 away from the limit pin 573. The suction assembly can be a piston suction device. The limit pin 573 is driven to move into the movable cavity 572 through the air extraction assembly (not shown in the figure).
[0058] In an embodiment of the present invention, another example of the reset member 575 is provided. It is a reset rod. The reset rod is slidably connected to the inner wall of the limit pin 573, and the contact part between the reset rod and the limit pin 573 has a matching inclined surface. When the reset rod moves, the limit pin 573 is pushed into the movable cavity 572 through the sliding of the inclined surface, as shown in Figure 4 , and the moving mode of the reset rod includes but is not limited to being driven by an electric telescopic rod.
[0059] In an embodiment of the present invention, on the basis of the above embodiment, a demolding solution for the helical gear 7 is provided. As shown in Figure 8 , for the helical gear 7, in the prior art, a rotating action is also required during demolding, otherwise it cannot be taken out of the cavity base 3. In this embodiment, on the basis of the above technical solution, only making the pushing cylinder 52 rotatable can complete the demolding of the helical gear 7, that is, the pushing cylinder 52 can rotate around its axis within the cavity base 3. The specific implementation includes the following steps:
[0060] In the ejection stage, the rotating member 54 drives the push rod 51 to rotate, so that the push rod 51 rotates to the end opposite to the lower axial groove 551. For the convenience of understanding, the pushing cylinder 52 is unfolded along the axis as shown in the figure, see Figure 7 . In the figure, the end opposite to the lower axial groove 551 is the left end, and the end opposite to the upper axial groove 551 is the right end. Then, the rotating member 54 and the moving member 53 are started simultaneously. The moving member 53 drives the push rod 51 to move upward, and the rotating member 54 drives the push rod 51 to rotate in the direction of the left end. Then, the injection molded part 6 will move upward and rotate simultaneously during the demolding process. Among them, the speeds at which the moving member 53 and the rotating member 54 drive the push rod 51 to move and rotate are related to the inclination of the tooth part of the gear, and are determined according to the specific specifications of the helical gear 7 during actual injection molding. This is prior art and will not be specifically described here. The subsequent further demolding process is the same as the foregoing.
[0061] It should be noted that in this embodiment, the axial groove 551 below is provided on the left side. Therefore, when the injection molded part 6 of the helical gear 7 is demolded, the rotation direction of the push rod 51 corresponds to the rotation of the push rod 51 towards the left end. If the tooth inclination direction of the helical gear 7 is in the other direction, the axial groove 551 below can be provided on the right side. That is to say, under the setting of this shaped guide groove 55, while moving upward, it only supports rotation in a single direction; generally, if the end faces on both sides of the helical gear 7 are symmetric structures, regardless of the tooth inclination direction, if there are differences between the two ends of the helical gear 7, the position of the axial groove 551 needs to be set according to factors such as the inclination direction;
[0062] In an embodiment of the present invention, a method for supporting the bidirectional rotation of the push cylinder 52 is provided, and its developed view is as Figure 9 shown. There are two axial grooves 551 located below in the guide groove 55, and they are symmetrically distributed. The middle of the annular groove 552 is connected to the axial groove 551 located above, and both ends of the annular groove 552 are respectively connected to the two axial grooves 551 located below. Through this setting, it is possible to support the rotation of the push cylinder 52 in any direction while the push rod 51 moves upward; or adopt the guide groove 55 as shown in Figure 10 shown. The specific method is the same as the above principle and will not be specifically described here.
[0063] In an embodiment of the present invention, the guide block 56 and the guide groove 55 can be set to two and be symmetrically distributed, which is beneficial to the stability of the movement and rotation of the push rod 51.
[0064] Finally, it should be noted that Figure 1 only a single injection molding station is illustrated in the figure, and actually multiple injection molding stations can also be set in an injection mold during implementation.
[0065] Only some exemplary embodiments of the present invention have been described by way of illustration above. Undoubtedly, for those of ordinary skill in the art, without departing from the spirit and scope of the present invention, the described embodiments can be modified in various different ways. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the protection scope of the present invention.
Claims
1. A demolding device for an injection-molded gear, comprising a moving mold (1) and a fixed mold (2). A cavity base (3) is installed in the fixed mold (2), and a core rod (4) is arranged in the cavity base (3). It is characterized in that, Further comprising: A pushing device (5), which includes a push rod (51) and a push cylinder (52). The push rod (51) is coaxially and rotatably connected to the bottom of the core rod (4). The push cylinder (52) is sleeved on the surfaces of the core rod (4) and the push rod (51), and the push cylinder (52) can move axially in the cavity base (3). The push rod (51) is connected to a moving member (53) for driving it to move along its own axis, and a rotating member (54) for driving it to rotate around its own axis; A guide groove (55) is formed on the inner wall of the push cylinder (52). The guide groove (55) includes two axial grooves (551) and a ring groove (552). Both ends of the ring groove (552) are communicated with the two axial grooves (551). A guide block (56) is arranged on one side of the push rod (51), and the guide block (56) can move along the guide groove (55); The pushing device (5) further includes a limiting member (57), and the limiting member (57) is used to limit the axial movement of the push cylinder (52).
2. The demoulding device for an injection-molded gear according to claim 1, characterized in that, The top of the push cylinder (52) is adapted to the bottom of the injection molded part (6).
3. The demoulding device for an injection-molded gear according to claim 1, characterized in that, The length of the upper axial groove (551) is 1 mm to 5 mm.
4. The demolding device for an injection-molded gear according to claim 1, wherein, The length of the lower axial groove (551) is greater than the distance that the top of the core rod (4) moves out of the bottom of the injection molded part (6).
5. The demoulding device for an injection-molded gear according to claim 1, characterized in that, The push rod (51) is connected to the core rod (4) through a detachable rotating assembly (58).
6. The demolding device for an injection-molded gear according to claim 5, characterized in that, The rotating assembly (58) includes two clamps (581). The two clamps (581) are detachably fixed to the bottom of the core rod (4) through fastening bolts, and a rotating cavity (582) for connecting the push rod (51) is formed in the middle of the two clamps (581). The top of the push rod (51) is clamped in the rotating cavity (582) and can rotate in the rotating cavity (582).
7. An ejection device for an injection-molded gear according to claim 1, characterized in that, The moving member (53) includes a moving plate (531) and a driving member A (532) for driving the moving plate (531) to move axially along the push rod (51).
8. An ejection device for an injection-molded gear according to claim 7, characterized in that, The rotating member (54) includes a rotating rod seat (541). The rotating rod seat (541) is rotatably connected to the moving plate (531). One end of the rotating rod seat (541) is connected to the bottom of the push rod (51) and is coaxial with it. A rotating rod (542) is slidably connected to the inner wall of the rotating rod seat (541), and the rotating rod (542) is connected to the output end of the motor (543).
9. The demoulding device for an injection-molded gear according to claim 1, characterized in that, The limiting member (57) includes a limiting groove (571) formed on the circumferential side of the push cylinder (52), and a movable cavity (572) formed in the cavity base (3). A limiting pin (573) is slidably installed in the movable cavity (572). A spring (574) is installed on one side of the limiting pin (573). The elastic force of the spring (574) acts on the limiting pin (573) to make it have a moving tendency to approach the push cylinder (52). The limiting member (57) further includes a reset member (575), which is used to drive the limiting pin (573) to move into the movable cavity (572).
10. A demolding device for an injection-molded gear according to any one of claims 1-9, characterized in that, The push cylinder (52) can rotate axially in the cavity base (3).