Method for injection molding a metal stub shaft with a composite blade

Abstract

The application discloses a method for integrally injection-molding a metal small shaft and a composite small blade, extending an easy-to-break tail section of the same material from a non-injection-molding end of the metal small shaft, processing a notch and a plane on the surface of the injection-molding end of the metal small shaft, placing a tooling on the outside of a mold cavity of an injection-molding mold and corresponding to the position of the metal small shaft, adjusting the clamping position of the metal small shaft on the tooling, starting injection molding, keeping the tooling clamping the tail section of the metal small shaft during the injection molding, and removing the tail section after the injection molding. The method accurately integrally injection-molds one end of the metal small shaft and an end of the composite small blade, ensures that the length direction of the metal small shaft exposed from the end of the composite small blade meets the specified length, and ensures that the metal small shaft does not rotate in the composite small blade or is not separated from the composite small blade due to loosening of the joint position during use, so that the metal small shaft and the composite small blade form an integrated louver blade.

Description

Technical Field

[0001] This invention belongs to the field of aircraft environmental control system technology, specifically relating to a processing method for injection molding one end of a metal shaft and a composite material blade into a louver structure. Background Technology

[0002] Adjustable louvered air vents are crucial accessories in military aircraft cockpits for adjusting the direction of airflow. Traditionally, aircraft cockpit vents are fixed, integral louvers, resulting in a fixed airflow direction that fails to meet pilot comfort requirements. To address this, the louvers are designed as adjustable structures, with the blades being the core component. Adjusting the blade angle allows for the adjustment of the airflow direction.

[0003] Because the metal shaft is small in size and light in weight, and the composite material blades are also small in size, when the metal shaft and composite material blades are injection molded as a single unit, the metal shaft is prone to drifting during the injection molding process, resulting in uncontrollable dimensions. In addition, if the metal shaft becomes loose during use, it is easy to detach or rotate. In order to accurately control the exposed shaft size and prevent the shaft from detaching or rotating in the event of looseness, the structure of the metal shaft needs to be improved, and the processing method needs to be adjusted to meet the usage requirements. Summary of the Invention

[0004] This invention aims to provide a method for injection molding a metal shaft and a composite material blade into one piece. By injection molding one end of the metal shaft and the composite material blade into one piece, the drift phenomenon of the metal shaft during the injection molding process is eliminated, the size and position of the exposed section of the metal shaft are controlled, the problem of the metal shaft detaching and loosening during use is prevented, and a standardized structural design concept is formed, which improves the safety and reliability of louver parts, improves the standardization design level of aircraft, and reduces the development risks brought about by the application of new structures.

[0005] This invention is achieved through the following technical solution:

[0006] A method for injection molding a metal shaft and a composite material blade into one piece, wherein both the metal shaft and the composite material blade are small-sized, lightweight parts, and the injection molding method includes...

[0007] A section of the same material, which is easily broken, extends from the non-injection molded end of the metal shaft (i.e., the part of the metal shaft that is not embedded in the composite material blade).

[0008] Grooves and planes are machined on the surface of the injection-molded end of the metal shaft (i.e., the part of the metal shaft embedded in the composite material blade). The grooves can increase the bonding force between the metal shaft and the composite material blade, while the planes can change the force mode and direction between the composite material blade and the surface of the metal shaft, thus avoiding relative rotation. At the same time, this solution allows for the replacement of the metal shaft and the composite material.

[0009] The metal shaft needs to be clamped throughout the entire process from the start of injection molding to the end of cooling to prevent it from drifting during injection molding and to prevent it from coming off during cooling due to differences in cooling rate and shrinkage.

[0010] Once the metal shaft meets the above conditions, place a tooling fixture on the outside of the injection mold cavity corresponding to the position of the metal shaft, adjust the clamping position of the metal shaft on the tooling, and start injection molding. During the injection molding process, always keep the tooling clamping the tail section of the metal shaft to ensure the size and position of the metal shaft exposed on the outside of the composite material blade. After the injection molding is completed, break off the excess tail section of the metal shaft.

[0011] Alternatively, the tail section on the metal shaft includes,

[0012] The clamping part held within the tooling;

[0013] The easily broken part has an outer diameter much smaller than the outer diameter of the injection-molded end of the metal shaft and the outer diameter of the clamping part, or the outer diameter of the broken part is the same as that of the clamping part but has a breakage groove on its surface.

[0014] Alternatively, the groove on the injection-molded end surface of the metal shaft is an annular groove distributed along the circumferential surface of the metal shaft, with at least one annular groove. Increasing the number of annular grooves can improve the bonding force between the metal shaft and the composite material blade.

[0015] Alternatively, the injection-molded end surface of the metal shaft is parallel to the axial direction of the metal shaft, and the vertical distance from the plane to the axis of the metal shaft is less than the radius of the metal shaft. The plane is formed on the metal shaft by removing material, which simplifies the processing.

[0016] Alternatively, during injection molding, the end face of the injection-molded metal shaft is aligned with the end face of the composite material blade, making it easier to observe and determine whether the exposed dimensions and position of the metal shaft meet the requirements.

[0017] Alternatively, the groove and plane on the injection-molded end surface of the metal shaft intersect to form a structural area that simultaneously prevents the metal shaft from rotating and detaching.

[0018] As an alternative, to avoid localized cracks at the interface between the metal shaft and the composite blade due to differences in their coefficients of contraction, a heating structure can be designed into the tooling to heat the metal shaft, ensuring that its cooling rate is as close as possible to the cooling rate of the composite blade, or in other words, minimizing the difference in their cooling rates. For example, a heating resistance wire can be added to the tooling to heat the metal shaft while it is being clamped.

[0019] Compared with the prior art, the injection molding method of the present invention has the following characteristics:

[0020] (1) A groove is machined on the surface of the injection-molded part of the metal shaft to ensure that the metal shaft will not come out when the fitting position of the composite material blade is loose;

[0021] (2) A flat surface is machined on the injection-molded part of the metal shaft to ensure that the metal shaft will not rotate when the fit position of the composite material blade is loose;

[0022] (3) Extend a portion of the non-injection molded part of the metal shaft for tooling clamping, thereby ensuring that the metal shaft will not move (drift) during the injection molding process due to its light weight, and ensuring that the size and position of the non-injection molded part (exposed part) of the metal shaft meet the design requirements. At the same time, the extended part has an easy-break structure, and the extended part can be easily removed when the injection molding is completed.

[0023] (4) When the cooling rate of the metal shaft and the composite material blades are significantly different, consider adding a heating structure to the tooling that holds the metal shaft to heat the metal shaft and control the cooling rate of the metal shaft so that the connection interface will not crack due to excessive temperature difference during the injection molding cooling stage. Attached Figure Description

[0024] Figure 1 A three-dimensional structural diagram of the final louver part, which is an integral part of the metal shaft and the composite material blade through injection molding.

[0025] Figure 2 This is a schematic diagram of a model in which one end of a small metal shaft is attached to a small composite blade without removing the tail section during injection molding.

[0026] Figure 3 A schematic diagram of a model during the injection molding process of attaching one end of a small metal shaft to a small composite blade.

[0027] In the figure, 1-metal shaft; 2-composite material blade; 3-tail section of metal shaft; 4-tooling; 5-injection mold. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, it should not be construed that the scope of the subject matter of the present invention is limited to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0029] To address the issues of easy drifting, detachment, or rotation of the metal shaft 1 embedded in the composite material blade 2 during injection molding, the basic idea of ​​this invention is to design an annular groove in the middle of the cylindrical portion of the metal shaft 1 embedded in the composite material blade 2 (increasing the contact surface between the composite material blade 2 and the metal shaft 1), and simultaneously design a local plane on the cylindrical surface (this plane is used to prevent the metal shaft 1 from rotating; the local plane may or may not intersect with the annular groove). A tail section 3 with a break groove (similar to a cut or a structure with a sharply reduced cross-section) is designed at the end of the metal shaft 1 exposed in the composite material blade 2. During injection molding, the tail section 3 of the metal shaft 1 is clamped in a tooling 4, and the injection section is placed in the injection mold 5 of the composite material blade 2. After injection molding is completed and the blade cools, the entire blade is removed, and the tail section 3 of the metal shaft 1 is removed, completing the injection molding of the louver part.

[0030] like Figure 1 The figure shown is a diagram of the final louver part after injection molding one end of the metal shaft 1 and the composite material blade into one piece according to the present invention; the structure is mainly achieved by injection molding the metal shaft 1 and the composite material blade 2 into one piece and then cutting off the tail section 3.

[0031] like Figure 2 The figure shown is a schematic diagram of the model before injection molding of one end of the metal shaft 1 with tail section 3 and the composite material blade 2. The figure mainly shows the tail section 3, the annular groove and the planar structure on the metal shaft 1.

[0032] like Figure 3 The figure shown is a schematic diagram of the process of injection molding one end of the metal shaft 1 and the composite material blade 2 according to the present invention. In the figure, the tail section 3 of the metal shaft 1 is clamped by the tooling 4 and placed into the injection mold 5.

[0033] The above embodiments are not intended to limit the scope of protection of the present invention. Any modifications, alterations or equivalent substitutions made based on the technical solutions of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for injection molding a small metal shaft and a small composite material blade into one piece, wherein both the small metal shaft (1) and the small composite material blade (2) are small-sized and lightweight parts, characterized in that: Methods for injection molding as a single unit include, A section of the same material, easily broken tail (3), extends from the non-injection molded end of the metal shaft (1). A groove and a flat surface are machined on the injection-molded end surface of the metal shaft (1); Once the metal shaft (1) meets the above conditions, place the fixture (4) on the outside of the mold cavity of the injection mold (5) corresponding to the position of the metal shaft (1), adjust the clamping position of the metal shaft (1) on the fixture (4), and start injection molding. During the injection molding process, always keep the fixture (4) clamping the tail section (3) of the metal shaft (1) to ensure the size and position of the metal shaft (1) exposed on the outside of the composite material blade (2). After the injection molding is completed, break off the excess tail section (3) on the metal shaft (1). The tail section (3) on the small metal shaft (1) includes: The clamping part is clamped in the tooling (4); The easily broken part has an outer diameter much smaller than the outer diameter of the injection end of the metal shaft (1) and the outer diameter of the clamping part, or the outer diameter of the broken part is the same as that of the clamping part but the surface has a breakage groove. The tooling (4) is designed with a heating structure to heat the metal shaft (1) while clamping it.

2. The method for injection molding a small metal shaft and a small composite material blade as described in claim 1, characterized in that: The groove on the injection end surface of the metal shaft (1) is an annular groove distributed along the circumferential surface of the metal shaft (1), and there is at least one annular groove.

3. The method for injection molding a small metal shaft and a small composite material blade as described in claim 1, characterized in that: The injection end surface plane of the metal shaft (1) is parallel to the axial direction of the metal shaft (1), and the vertical distance from the plane to the axis of the metal shaft (1) is less than the radius of the metal shaft (1).

4. The method for injection molding a small metal shaft and a small composite material blade as described in claim 1, characterized in that: During injection molding, the end of the injection end surface of the metal shaft (1) is aligned with the end face of the composite material blade (2).

5. The method for injection molding a small metal shaft and a small composite material blade as described in claim 1, characterized in that: The groove and the plane on the injection-molded end surface of the metal shaft (1) intersect.

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