A plastic injection mold with a cavity cleaning function

Abstract

The utility model belongs to injection mold technical field, concretely relates to a kind of injection mold with the cavity-free function of plastic package forming of exempting from. It includes fixed mould and movable mould, fixed mould or movable mould is equipped with mould core, the mould core includes top mould core, inner expansion core and multi-petal outer expansion sleeve, the inner expansion core is the polyhedral structure that each outer side is wedge-shaped inside has along axial through cavity, the outer cylinder with through cavity is surrounded by the outer cylinder with through cavity in the axial direction by multiple expansion petals of the multi-petal outer expansion sleeve, the inner expansion core is located in the through cavity inside the multi-petal outer expansion sleeve and each corresponding wedge surface is connected with each other, the top mould core is a cylindrical body of one step, and the top mould core is located at the top of the multi-petal outer expansion sleeve.The injection mold provided by the utility model can cancel the polishing, roller brush, blowing cleaning and other processes of the inner cavity after stator injection, reduce cost, improve production efficiency and product quality stability.

Description

Technical Field

[0001] This utility model belongs to the field of injection mold technology, specifically relating to an injection mold with a cavity-cleaning function for sealing. Technical Background

[0002] Plastic-encapsulated motors utilize BMC / SMC composite materials and other encapsulation technologies to integrally encapsulate the motor's stator core and windings with engineering plastics, eliminating the need for traditional stator insulation processes and the metal casing of ordinary motors. Compared to traditional casing motors, plastic-encapsulated motors offer the following advantages: 1. Aesthetically pleasing appearance, smaller size, and lighter weight; the length and weight are reduced by approximately 25% compared to metal-cased motors. Assembly is also convenient, making them suitable for mass automated production. 2. Low noise. The symmetrical concentric encapsulation of the stator core and the plastic structure improve stator coaxiality, reducing operating noise. Under mains frequency power, the sound pressure level of plastic-encapsulated motors is 7 dB lower than that of casing motors; under variable frequency power, it is reduced by 9 dB. 3. Low vibration. Because the motor stator is now a single unit, the rotor imbalance is small, suppressing vibration. 4. Excellent insulation performance. These advantages have led to the widespread application of plastic-encapsulated motors in encapsulated electrical appliances.

[0003] Currently, common problems in the process of molding the stator of a plastic-encapsulated motor through injection molding after winding include: 1. In traditional injection molding, employees or robots place the wound stator into the lower mold cavity core. After the core is positioned with the inner circle of the stator, the injection molding is completed. Due to the unavoidable gap between the outer circle of the core and the inner circle of the iron core, some injection plastic overflows into the gap during the injection molding process and eventually sticks to the inner circle of the stator. This is a product defect. After injection molding, it must be cleaned by grinding, roller brushing, air blowing, etc., which results in a waste of manufacturing costs such as labor, equipment, and time.

[0004] 2. Cleaning the inner circle of the stator can cause problems such as tooth warping, deformation, and gaps, which can reduce production efficiency and product quality stability.

[0005] 3. In traditional multi-part mold production, the presence of a slider on the top of the product will cause glue overflow, which reduces product quality and motor performance.

[0006] There is an urgent need to find a method or device to solve the problems existing in the current process of molding motor stators. Summary of the Invention

[0007] In order to solve the above-mentioned problems in the prior art, the purpose of this utility model is to provide a plastic sealing injection mold with a cavity-cleaning function.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A molding die for encapsulation with cavity-free cleaning function includes a fixed mold and a moving mold. The fixed mold or moving mold is equipped with a mold core, which includes a top mold core, an inner expansion core, and a multi-lobed outer expansion sleeve. The inner expansion core is a polyhedral structure with wedge-shaped outer surfaces and an axially penetrating cavity. The multi-lobed outer expansion sleeve is an outer cylinder with an axially penetrating cavity formed by multiple expansion lobes. The inner expansion core is located within the penetrating cavity of the multi-lobed outer expansion sleeve, and the corresponding wedge-shaped surfaces are mutually connected. The top mold core is a stepped cylinder located at the top of the multi-lobed outer expansion sleeve.

[0010] Preferably, the wedge angles of the outer surfaces of the inner expansion core are equal or unequal.

[0011] Preferably, each expansion petal of the multi-lobed outer expansion sleeve has at least one guide groove on its inner surface, and the outer surface of the inner expansion core has guide ribs that correspond to and cooperate with the guide grooves. The guiding direction of the guide ribs is at a certain angle to the axis of the mold core and is coplanar.

[0012] Preferably, each of the inner expansion cores has at least one guide groove on its outer surface, and each of the expansion petals of the multi-lobed outer expansion sleeve has a guide rib on its inner surface that corresponds to and cooperates with the guide groove. The guiding direction of the guide rib is at a certain angle to the axis of the mold core and is coplanar.

[0013] Preferably, a top mold core drag rod is provided inside the axial through cavity of the multi-lobed external expansion sleeve.

[0014] Preferably, the bottom of each expansion petal of the multi-lobed outer expansion sleeve is provided with a transmission mechanism for dragging the expansion petal movement.

[0015] Preferably, the transmission mechanism includes a connecting rod and at least one sliding plate. At least one connecting rod is provided at the bottom of each expansion petal. A mold core seat is provided between the inner expansion core and the sliding plate. The mold core seat is fixedly connected to the bottom of the inner expansion core. The mold core seat is provided with multiple through holes. Each connecting rod and the top mold core pass through the corresponding through holes on the mold core seat and are connected to the sliding plate.

[0016] More preferably, the connection between the connecting rod and the expansion valve is a fixed connection or a sliding connection.

[0017] Preferably, the wedge angle between the inner expansion core and the multi-lobed outer expansion sleeve does not exceed 25 degrees.

[0018] Preferably, at least one guide rib is provided on the outer side of at least one expansion petal of the multi-lobed outer expansion sleeve and the top mold core, and the guide ribs on the multi-lobed outer expansion sleeve and the guide ribs on the top mold core have the same cross-section and are completely aligned.

[0019] Compared with related technologies, the molding die for sealing stator inner rings provided by this utility model has the following advantages:

[0020] The mold provided by this utility model can achieve no overflow of material in the inner circle of the stator after injection molding and no overflow of glue on the top slider. It eliminates the need for grinding, brushing, and air blowing cleaning, which can reduce manufacturing labor, equipment, and time costs, reduce the risk of defects such as tooth warping, deformation, and gaps caused by cleaning in the inner circle of the stator, and improve production efficiency and product quality stability. Attached Figure Description

[0021] Figure 1 These are two types of mold cores for traditional motor stator encapsulation injection molds;

[0022] Figure 2 This is a schematic diagram of the core structure of the injection mold for molding the motor stator provided in Embodiment 1 of this utility model;

[0023] Figure 3 for Figure 2 A cross-sectional view of the core part of the mold;

[0024] Figure 4 for Figure 2 A cross-sectional view of the core part of the mold;

[0025] Figure 5 for Figure 2 A cross-sectional view of the multi-lobed external expansion sleeve of the mold after expansion;

[0026] Figure 6 A cross-sectional view of the core part of the mold provided in Example 2;

[0027] Figure 7 This is a schematic diagram of the mold core structure during the shrinkage of the outer expansion sleeve of the mold provided in Example 3;

[0028] Figure 8 This is a schematic diagram of the mold core structure during the expansion of the mold outer sleeve provided in Example 3;

[0029] Figure 9 This is a schematic diagram of the mold core structure during the shrinkage of the outer expansion sleeve of the mold provided in Example 4;

[0030] Figure 10 This is a schematic diagram of the mold core structure when the outer expansion sleeve of the mold expands as provided in Example 4. Detailed Implementation

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the following description, only certain exemplary embodiments of the present invention are described by way of illustration. Undoubtedly, those skilled in the art will recognize that the described embodiments can be modified in different ways without departing from the spirit and scope of the present invention. Therefore, the drawings and description are illustrative in nature and not intended to limit the scope of the claims. In this embodiment, directional terms such as "bottom," "top," "outer side," "inner side," and "inner" are relative to the mold core; for example, the inner expansion core is located inside the multi-lobed outer expansion sleeve.

[0032] Example 1

[0033] like Figure 1 The diagram shown is a schematic of the core structure of a traditional motor stator molding injection mold.

[0034] like Figure 2-5 As shown, this utility model provides a molding die for encapsulation with a cavity-cleaning function, which includes a fixed mold and a moving mold. The fixed mold or moving mold is provided with a mold core, which includes a top mold core 1, an inner expansion core 3 and a multi-lobed outer expansion sleeve 2. The inner expansion core 3 is a polyhedral structure with wedge-shaped outer surfaces and an axially penetrating cavity inside. The multi-lobed outer expansion sleeve 2 is an outer cylinder with an axially penetrating cavity surrounded by multiple expansion lobes. The inner expansion core 3 is located in the penetrating cavity inside the multi-lobed outer expansion sleeve 2 and the corresponding wedge-shaped surfaces are connected to each other. The top mold core 1 is a stepped cylinder and is located at the top of the multi-lobed outer expansion sleeve 2.

[0035] In this embodiment, the wedge angle α of each outer surface 31 of the inner expansion core 3 is equal, and the wedge angle β of each inner surface 21 of the multi-lobed outer expansion sleeve 2 is equal. The wedge angles α and β do not exceed 25 degrees, and those skilled in the art can make corresponding adjustments according to actual needs. α is the angle between the side surface of the inner expansion core and the axis of the mold core. β is the angle between each inner surface of the outer expansion sleeve and the axis of the mold core.

[0036] Each expansion petal of the multi-lobed outer expansion sleeve has at least one guide groove 24 on its inner surface. The expansion core has guide ribs 12 along its circumference that correspond to the guide grooves. The guiding direction of the guide ribs forms a certain angle with the axis of the mold core and is coplanar. Each expansion petal of the multi-lobed outer expansion sleeve 2 has at least one guide groove 24 on its inner surface. The outer surface of the inner expansion core 3 has guide ribs 32 that correspond to the guide grooves. The guiding direction of the guide ribs 32 forms a certain angle with the axis of the mold core and is coplanar. The guiding direction of each guide rib is parallel to the side surface where it is located. The shape of the guide ribs is not limited; for example, they can be rectangular, V-shaped, dovetail-shaped, T-shaped, or any cross-section that satisfies the guiding function.

[0037] A top mold core drag rod 6 is installed inside the axial through cavity of the multi-lobed external expansion sleeve 2.

[0038] The multi-lobed external expansion sleeve 2 has a transmission mechanism at the bottom of each expansion lobe for dragging the expansion lobe movement.

[0039] like Figure 2-3 As shown, in this embodiment, the transmission mechanism includes a connecting rod 5 and at least one sliding plate 7. At least one connecting rod is provided at the bottom of each expansion petal. A mold core seat 4 is provided between the inner expansion core and the sliding plate. The mold core seat 4 is fixedly connected to the bottom of the inner expansion core 3, and the bottom protrusion of the inner expansion core 3 is placed in the top groove of the mold core seat 4. The mold core seat 4 has multiple through holes, and each connecting rod 5 and the top mold core drag rod 6 pass through the corresponding through holes on the mold core seat 4 and connect to the sliding plate 7. The connection method between the connecting rod 5 and the expansion petal is a fixed connection, which is a common connection method in the art. For example, it can be a threaded connection or fixed by welding. As a preferred embodiment, the connecting rod is a hexagonal head bolt.

[0040] The cross-sectional dimension of the through hole in the mold core seat 4 is larger than that of the middle cross-section of the connecting rod 5, ensuring that the horizontal translation of the connecting rod 5 along its axial direction does not interfere with the mold core seat 4. The mold core seat 4 is used to limit the extreme position of the downward movement of the expansion flap.

[0041] In this embodiment, multiple stepped holes are formed on the sliding plate 7, and the connecting rod 5 passes through each corresponding stepped hole. The cross-sectional dimension of the stepped hole in the sliding plate 7 is larger than the cross-sectional dimension of the middle part of the connecting rod 5 and smaller than the cross-sectional dimension of the bottom part of the connecting rod 5. This structure ensures that when the sliding plate 7 moves along its axial direction while dragging the connecting rod 5, its horizontal translation does not interfere with the sliding plate 7, and the top of the connecting rod 5 cannot slide out of the stepped hole in the sliding plate 7. The shape of the through holes and stepped holes on the mold core seat 4 and the sliding plate 7 is not limited, but oblong holes are preferred.

[0042] In this embodiment, at least one positioning rib 11 and 25 are provided on the outer side of at least one expansion petal of the multi-lobed outer expansion sleeve 2 and the top mold core 1 for positioning during stator molding.

[0043] In another implementation, the mold core is mounted on the moving mold.

[0044] Example 2

[0045] like Figure 6 As shown, the difference between this embodiment and embodiment 1 is that the cross section of the inner top mold core 1 and the inner through cavity of the expansion core 3 is a large semi-circle, which can prevent the top mold core 1 from rotating relative to the expansion core 3. The rest is the same as in embodiment 1.

[0046] Example 3

[0047] like Figure 7-8 As shown, in this embodiment, the wedge angles α on the outer surfaces of the inner expansion core 3 are not equal, and the wedge angles β on the inner surfaces of the multi-lobed outer expansion sleeve are not equal. For example, the outer expansion sleeve has 6 lobes, where the wedge angles on the inner surfaces of all 6 expansion lobes are not the same, or at least 2 of them are not equal.

[0048] Unlike the technical solutions with the same wedge angle α provided in Embodiments 1 and 2, the size of the through holes on the sliding plate 7 and the mold core seat 4 in this embodiment needs to be adjusted accordingly as the wedge angle changes. This ensures that the horizontal translation of the connecting rod 5 along its axial direction does not interfere with the sliding plate 7 and the mold core seat 4.

[0049] In this implementation, the remaining structure is the same as in Example 1 or Example 2.

[0050] Example 4

[0051] As shown in 9-10, in this embodiment, the connecting rod 5 and the outer expansion sleeve 2 are slidably connected, and the through hole size on the mold core seat 4 and the sliding plate 7 is the same as the connecting rod cross-sectional size, and the two are clearance-fitted.

[0052] The difference between this embodiment and embodiments 1-3 is that the direction of movement of the connecting rod 5 is parallel to the axis of the mold core. When the connecting rod moves up and down, the expansion flap 2 and the connecting rod 5 slide against each other.

[0053] In embodiments 1-3, the movement direction of the connecting rod 5 is parallel to the guide direction, and there is a horizontal translation when the connecting rod moves along the guide direction.

[0054] The mold structure provided by this utility model is not limited to the structure provided in the above embodiments, and any reasonable structural changes or combinations can be made based on the above embodiments.

[0055] The working principle of the mold provided by this utility model is as follows:

[0056] Assuming the mold core is fixed on the fixed mold, during the molding of the motor stator, the stator coil is first nested on the outside of the multi-lobed outer expansion sleeve. During nesting, the direction of the stator coil needs to be adjusted to ensure that the locating ribs on the expansion lobes and the top mold core are inserted into the tooth grooves of the stator coil. Then, the stator coil is pushed downwards to the bottom to contact the mold core seat. Finally, the mold is closed. During the mold closing process, the ejector rod on the moving mold pushes the sliding plate downwards. As the sliding plate moves downwards, it drags the top mold core and each expansion lobe of the multi-lobed outer expansion sleeve along the guide rod via the top mold core drag rod and connecting rod. The multi-lobed outer expansion sleeve moves in the direction of the guide ribs and guide grooves until the mold is closed. During this process, each expansion lobe of the multi-lobed outer expansion sleeve is expanded, and the outer ring size increases to ensure that the multi-lobed outer expansion sleeve is tightly fitted with the inner ring of the stator coil. Then the injection molding process begins. When the mold opens, the moving mold moves upward and the ejector pin on the moving mold gradually moves away from the ejector plate. At the same time, the ejector pin on the ejector plate of the fixed mold pushes the sliding plate upward. Meanwhile, the multi-lobed outer expansion sleeve moves upward under the drag of the stator after injection molding and encapsulation. Each expansion lobe contracts, and the outer ring size decreases, making demolding easier.

[0057] Conversely, the same principle applies when the mold core is fixed on the moving mold.

[0058] The above descriptions are illustrative embodiments of this utility model and are not intended to limit the scope of this utility model. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of this utility model should fall within the protection scope of this utility model.

Claims

1. A molding die for encapsulation with cavity-cleaning-free function, comprising a fixed mold and a moving mold, characterized in that, The fixed mold or moving mold is provided with a mold core, which includes a top mold core, an inner expansion core, and a multi-lobed outer expansion sleeve. The inner expansion core is a polyhedral structure with wedge-shaped outer surfaces and an axially penetrating cavity inside. The multi-lobed outer expansion sleeve is an outer cylinder with an axially penetrating cavity surrounded by multiple expansion lobes. The inner expansion core is located inside the penetrating cavity of the multi-lobed outer expansion sleeve, and the corresponding wedge-shaped surfaces are connected to each other. The top mold core is a stepped cylinder located at the top of the multi-lobed outer expansion sleeve.

2. The injection mold with cavity-cleaning-free molding function according to claim 1, characterized in that, The wedge angles of the outer surfaces of the inner expansion core may be equal or unequal.

3. The injection mold with cavity-cleaning-free molding function according to claim 1, characterized in that, Each expansion petal of the multi-lobed external expansion sleeve has at least one guide groove on its inner surface, and the outer surface of the inner expansion core has guide ribs that correspond to and cooperate with the guide grooves. The guiding direction of the guide ribs is at a certain angle to the axis of the mold core and is coplanar.

4. The injection mold with cavity-cleaning-free molding function according to claim 1, characterized in that, The outer surface of each inner expansion core is provided with at least one guide groove, and the inner surface of each expansion petal of the multi-lobed outer expansion sleeve is provided with guide ribs that correspond to and cooperate with the guide grooves. The guiding direction of the guide ribs is at a certain angle to the axis of the mold core and is coplanar.

5. The injection mold with cavity-cleaning-free molding function according to claim 1, characterized in that, A top mold core drag rod is installed inside the axial through cavity of the multi-lobed external expansion sleeve.

6. The injection mold with cavity-cleaning-free molding function according to claim 1, characterized in that, The bottom of each expansion valve of the multi-lobed external expansion sleeve is provided with a transmission mechanism for dragging the expansion valve movement.

7. The injection mold with cavity-cleaning-free molding function according to claim 6, characterized in that, The transmission mechanism includes a connecting rod and at least one sliding plate. At least one connecting rod is provided at the bottom of each expansion petal. A mold core seat is provided between the inner expansion core and the sliding plate. The mold core seat is fixedly connected to the bottom of the inner expansion core. The mold core seat is provided with multiple through holes. Each connecting rod and the top mold core pass through the corresponding through holes on the mold core seat and are connected to the sliding plate.

8. The injection mold with cavity-cleaning-free molding function according to claim 7, characterized in that, The connection between the connecting rod and the expansion valve can be either a fixed connection or a sliding connection.

9. The injection mold with cavity-cleaning-free molding function according to any one of claims 1-8, characterized in that, The wedge angle of the inner expansion core and the multi-lobed outer expansion sleeve does not exceed 25 degrees.

10. The injection mold with cavity-cleaning-free molding function according to any one of claims 1-8, characterized in that, At least one guide rib is provided on the outer side of at least one expansion petal of the multi-lobed outer expansion sleeve and the top mold core. The guide ribs on the multi-lobed outer expansion sleeve and the guide ribs on the top mold core have the same cross-section and are completely aligned.

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