Demolding mechanism for automobile part production and injection molding machine

Abstract

The invention relates to a demolding mechanism for automobile part production and an injection molding machine. The mold comprises a hollow shaft and an inner cavity mold, the inner cavity mold is composed of a core base, a driving sliding block, a driven sliding block and a top cover, trapezoidal guide rails are arranged on the binding faces of the two sides of the driving sliding block, and trapezoidal guide grooves are formed in the binding faces of the two sides of the driven sliding block; a plurality of fixed guide rods and a plurality of screw rods are arranged on the core seat in a circumferential array radiation mode, the fixed guide rods and the driven sliding blocks are in sliding insertion connection in a one-to-one correspondence mode, the screw rods and the driving sliding blocks are in screwing fit in a one-to-one correspondence mode, a transmission shaft is arranged in the hollow shaft in a penetrating mode, and the transmission shaft is in transmission connection with the screw rods. The contraction and expansion actions of the outer contour of the inner cavity mold are realized by controlling the positive and negative rotation of the transmission shaft, and compared with sliding block core-pulling demolding, the demolding actions are all carried out in the inner cavity mold, and an external structure is hardly interfered, so that the constraint on spatial layout is relatively small, and the structural design freedom degree is relatively high.

Description

Technical Field

[0001] This invention relates to a demolding mechanism, and more particularly to a demolding mechanism and injection molding machine for the production of automotive parts. Background Technology

[0002] A large number of plastic parts are used in automobiles, most of which are produced by injection molding machines. When the mold on the injection molding machine has an undercut structure, existing solutions generally fall into three categories: Slider core-pulling demolding, which uses a slider mechanism in conjunction with inclined guide pillars to separate the undercut area laterally before ejecting the product. This is suitable for deep undercut structures with large angles, and non-destructive demolding can be achieved by adjusting the slider stroke and angle (usually around 35°); Ejector plate demolding, where when the undercut is located at the bottom of the product, an ejector plate that matches the shape of the inner cavity is used to eject the entire part, avoiding deformation or breakage caused by local stress; and Pneumatic demolding, which uses an air valve inside the mold to inject compressed air after mold opening to create a pressure difference, separating the product from the cavity. This is especially suitable for complex structures with thin walls or low adhesion.

[0003] Slider core pulling demolding is the most common demolding structure for undercut structures. However, it also has some drawbacks, such as strong spatial layout constraints. Multi-slider systems require strict planning of motion sequence and spatial avoidance. Complex products require sacrifice of structural design freedom. In addition, the undercut depth is limited. When the core pulling stroke exceeds 100mm, the rigidity of the mechanism decreases significantly, and a hydraulic staged core pulling or secondary ejection solution needs to be used. Summary of the Invention

[0004] This invention provides a demolding mechanism and injection molding machine for automotive parts production, solving the problem of strong spatial layout constraints in the prior art.

[0005] The above-mentioned technical problem of the present invention is mainly solved by the following technical solution: a demolding mechanism for automobile parts production, comprising: a hollow shaft and an inner cavity mold disposed at the end, the inner cavity mold being composed of a core seat fixed to the end of the hollow shaft, a plurality of active sliders arranged circumferentially around the core seat, a plurality of driven sliders arranged circumferentially around the core seat, and a top cover, wherein the number of active sliders and driven sliders is the same, they are staggered and mutually fitted, trapezoidal guide rails are provided on both sides of the contact surface of the active sliders, and trapezoidal guide grooves are provided on both sides of the contact surface of the driven sliders, the trapezoidal guide rails and the trapezoidal guide grooves slidingly engaging with each other. The distance between the two trapezoidal guide rails on the active slider is set to be wider on the outside and narrower on the inside; the core seat is circumferentially arrayed with several fixed guide rods and several screws, the fixed guide rods are slidably inserted into the driven slider in a one-to-one correspondence, and the screws are screwed into the active slider in a one-to-one correspondence. A transmission shaft passes through the hollow shaft, and the transmission shaft is rotatably engaged with the core seat. The end of the transmission shaft is provided with an active bevel gear, and the screws are also rotatably engaged with the core seat. The inner end of the screw is provided with a driven bevel gear that meshes with the active bevel gear. A connecting body is fixedly connected between the top cover and the core seat; the outer end of the transmission shaft is connected to the servo motor for transmission.

[0006] This invention is applicable to plastic parts with large internal cavity dimensions and small opening dimensions. A hollow shaft is connected to a moving mechanism to control the opening and closing of the internal mold. The widest point of the outer contour of the internal mold is located on the active and driven sliders. The outer contour dimension of the top cover is smaller than the opening dimension of the plastic part. The demolding principle of this invention is as follows: Before the hollow shaft performs pull-out demolding, the drive shaft rotates under control, and the active bevel gear rotates synchronously, thereby driving all the driven bevel gears to rotate synchronously. Each screw has the same pitch. Driven by the screws, all the active sliders retract synchronously. Since the driven sliders are in a slanted sliding fit with the active sliders, all the driven sliders also retract inward, thus reducing the maximum outer contour dimension of the internal mold to be smaller than the opening dimension of the plastic part. Then, the hollow shaft performs a pull-out action to achieve demolding. Conversely, when the drive shaft reverses, the internal mold can be restored.

[0007] Furthermore, the driven slider has protruding limiting steps on both sides of its contact surface to restrict the driving slider. When the driving slider returns to its original position to the outside, it will eventually abut against the limiting steps, at which point it will be fully reset.

[0008] The present invention also provides an injection molding machine, including an injection molding machine body and an injection mold, wherein the injection mold is provided with a demolding mechanism, and the demolding mechanism is the above-mentioned demolding mechanism for automobile parts production.

[0009] Therefore, the present invention has the following characteristics compared with the prior art: 1. The present invention realizes the expansion and contraction of the outer contour of the inner cavity mold by controlling the forward and reverse rotation of the transmission shaft. Compared with the core pulling demolding of the slider, its demolding action occurs in the inner cavity mold and has almost no interference with the external structure. Therefore, it has less constraint on spatial layout and relatively high degree of freedom in structural design. Attached Figure Description

[0010] Appendix Figure 1 This is a partial exploded view of the present invention;

[0011] Appendix Figure 2 This is a cross-sectional view of the present invention when the mold is closed;

[0012] Appendix Figure 3 This is a cross-sectional view of the present invention when the mold is being opened;

[0013] Appendix Figure 4 This is an axial sectional view of the present invention when the mold is closed. Detailed Implementation

[0014] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0015] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0016] Example 1: See Figure 1 , Figure 2 and Figure 4A demolding mechanism for automotive parts production includes: a hollow shaft 100 and an inner cavity mold 200 located at one end. The hollow shaft has a flange 110 at its end. The inner cavity mold consists of a core seat 210 fixed to the end of the hollow shaft, four active sliders 220 arranged circumferentially around the core seat, four driven sliders 230 arranged circumferentially around the core seat, and a top cover 240. The active and driven sliders are staggered and fit together. Trapezoidal guide rails 221 are provided on both sides of the active slider's contact surface, and trapezoidal guide grooves 231 are provided on both sides of the driven slider's contact surface. The trapezoidal guide rails and trapezoidal guide grooves slide against each other. The distance between the two trapezoidal guide rails on the movable slider is set to be wider on the outside and narrower on the inside; four fixed guide rods 250 and four screws 260 are arranged radially in a circular array on the core seat. The fixed guide rods are slidably inserted into the driven slider in a one-to-one correspondence, and the screws are screwed into the active slider in a one-to-one correspondence. A transmission shaft 270 is inserted through the hollow shaft. The transmission shaft is rotatably engaged with the core seat. The end of the transmission shaft is provided with an active bevel gear 271. The screw is also rotatably engaged with the core seat. The inner end of the screw is provided with a driven bevel gear 261 that meshes with the active bevel gear. A connecting body 280 is fixedly connected between the top cover and the core seat; the outer end of the transmission shaft is connected to the servo motor for transmission.

[0017] See Figure 2 The driven slider has protruding limiting steps 232 on both sides of its contact surface to limit the active slider. When the active slider returns to its original position to the outside, it will eventually abut against the limiting steps, at which point it will be reset.

[0018] See Figure 1 and Figure 4 An active neck 222 is provided on the end face of the active slider near the hollow shaft, and a driven neck 233 is provided on the end face of the driven slider near the hollow shaft. The active neck and the driven neck together constitute the neck. The outer contour dimension of the top cover is smaller than the outer contour dimension of the neck.

[0019] See Figure 4 A stud 241 is fixed in the center of the top cover, and a screw hole 281 is provided on the top of the connector to be screwed into the stud. This installation method facilitates disassembly and replacement later.

[0020] Specifically, the clamping angle between the two trapezoidal guide rails is between 5° and 15°.

[0021] See Figure 2 and Figure 3This embodiment is applicable to plastic parts with large internal cavity dimensions and small opening dimensions. The hollow shaft is connected to the moving mechanism to control the opening and closing of the internal mold. The widest position of the outer contour dimension of the internal mold is located on the active and driven sliders. The demolding principle of this embodiment is as follows: Before the hollow shaft performs pull-out demolding, the transmission shaft rotates under control, and the active bevel gear rotates synchronously, thereby driving all the driven bevel gears to rotate synchronously. Each screw has the same pitch. Driven by the screws, all the active sliders retract inward synchronously. Since the driven sliders are in oblique sliding fit with the active sliders, all the driven sliders also retract inward, thereby reducing the maximum outer contour dimension of the internal mold to be smaller than the opening dimension of the plastic part. Then the hollow shaft performs a pull-out action to achieve demolding; conversely, the transmission shaft reverses, and the internal mold can be restored.

[0022] This embodiment also discloses an injection molding machine, including an injection molding machine body and an injection mold, wherein the injection mold is provided with a demolding mechanism, which is the aforementioned demolding mechanism for automobile parts production.

[0023] It will be apparent to those skilled in the art that the present invention can be modified in various ways, and such modifications are not considered to depart from the scope of the invention. All such modifications that are obvious to those skilled in the art are included within the scope of the claims.

Claims

1. A demolding mechanism for automotive parts manufacturing, characterized in that, include: The system comprises a hollow shaft and an inner cavity mold located at its end. The inner cavity mold consists of a core seat fixed to the end of the hollow shaft, several active sliders arranged in a circular array around the core seat, several driven sliders arranged in a circular array around the core seat, and a top cover. The number of active sliders and driven sliders is the same, and they are staggered and closely fitted together. Trapezoidal guide rails are provided on both sides of the contact surface of the active sliders, and trapezoidal guide grooves are provided on both sides of the contact surface of the driven sliders. The trapezoidal guide rails and the trapezoidal guide grooves slide against each other. Between two trapezoidal guide rails on the same active slider... The spacing is set to be wider on the outside and narrower on the inside; the core seat is provided with a plurality of fixed guide rods and a plurality of screws arranged in a circumferential array. The fixed guide rods are slidably inserted into the driven slider in a one-to-one correspondence, and the screws are screwed into the active slider in a one-to-one correspondence. A transmission shaft is inserted through the hollow shaft. The transmission shaft is rotatably engaged with the core seat. The end of the transmission shaft is provided with an active bevel gear. The screws are also rotatably engaged with the core seat. The inner end of the screws is provided with a driven bevel gear that meshes with the active bevel gear. A connecting body is fixedly connected between the top cover and the core seat.

2. The demolding mechanism for automotive parts production according to claim 1, characterized in that: The driven slider has protruding limiting steps on both sides of its contact surface to restrict the active slider.

3. The demolding mechanism for automotive parts production according to claim 1, characterized in that: An active neck is provided on the end face of the active slider near the hollow shaft, and a driven neck is provided on the end face of the driven slider near the hollow shaft. The active neck and the driven neck together constitute a neck.

4. The demolding mechanism for automotive parts production according to claim 1, characterized in that: A stud is fixed at the center of the top cover, and a screw hole is provided at the top of the connector for screwing in with the stud.

5. The demolding mechanism for automotive parts production according to claim 1, characterized in that: The clamping angle between the two trapezoidal guide rails is between 5° and 15°.

6. An injection molding machine, comprising an injection molding machine body and an injection mold, wherein the injection mold is provided with a demolding mechanism, characterized in that: The demolding mechanism is the demolding mechanism for automobile parts production as described in any one of claims 1 to 5.

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