A special fixture for thin-walled hemispherical carbon fiber composite material cowling

Abstract

The utility model belongs to the technical field of machining, disclose a kind of special fixture of thin-walled hemispherical carbon fiber composite material machine cover, including clamping body and auxiliary support body, clamping body is the annular structure of thin on top thick as a whole, and the inside and outside of its top are all provided with step surface;Multiple radial through holes are evenly provided on the upper and lower parts of clamping body along circumference, and the outer wall surface of the through hole is provided as a plane.The technical scheme of the utility model enhances the rigidity of thin-walled hemispherical machine cover by the setting of auxiliary hemispherical glass fiber material support, reduces deformation in the processing, and further improves product quality.

Description

Technical Field

[0001] This utility model belongs to the field of machining technology, specifically relating to a special fixture for a thin-walled hemispherical carbon fiber composite material machine cover. Background Technology

[0002] Carbon fiber composites possess advantages such as high specific strength and fatigue resistance, but during processing, they are prone to problems such as delamination, fiber pull-out, and rapid tool wear. This is especially true for thin-walled hemispherical fuselages, which have thin walls, poor rigidity and stability, and are susceptible to clamping and processing deformation, resulting in low processing efficiency and impacting processing accuracy and product quality. Thin-walled hemispherical fuselages based on carbon fiber composites are a typical type of aircraft component, such as... Figure 1 As shown. In CNC machining, hemispherical machine covers typically require observation holes, through holes, threaded holes, long slots, etc., on their top and side surfaces. Therefore, the clamping and positioning of this part becomes a crucial factor restricting its machining accuracy and quality. In actual machining, such parts are generally clamped and positioned by applying radial compressive force to the bottom circumference or radial pressure to the top of the machine cover.

[0003] Combination Figure 1 During machining, the top-down clamping method can easily cause workpiece deformation or even fiber breakage due to pressure from the top. This clamping method also affects the machining of the top circular hole. When using a bottom-circumferential clamping method, uneven radial forces can cause deformation or even cracking of the spherical shell. Furthermore, both of these clamping methods have relatively low clamping force, resulting in unstable clamping and inaccurate positioning. Under the cutting force of the tool, the part will vibrate and shift, failing to achieve the maximum efficiency of the tool, affecting machining accuracy, and posing safety hazards. A new type of specialized fixture is urgently needed to solve these problems. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] The technical problem to be solved by this utility model is the clamping deformation, low positioning accuracy and processing vibration of thin-walled hemispherical machine covers based on carbon fiber composite materials in CNC machining.

[0006] (II) Technical Solution

[0007] To solve the above-mentioned technical problems, this utility model provides a special fixture for a thin-walled hemispherical carbon fiber composite material machine cover, including a fixture body and an auxiliary support body. The fixture body is a ring-shaped structure with a thinner top and a thicker bottom, and stepped surfaces are provided on both the inner and outer sides of its top. Multiple radial through holes are evenly provided along the circumference of the upper and lower parts of the fixture body, and the outer wall surface of the through holes is set as a plane. The auxiliary support body is a hemispherical structure with a cylindrical section at its bottom and corresponding slots on its spherical outer surface. The position of the slots is consistent with the position to be processed of the hemispherical machine cover. The bottom cylindrical section of the auxiliary support body is located inside the fixture body, and the two are fixed by bolts.

[0008] The hemispherical cover to be processed is fastened to the top of the auxiliary support body, and its bottom is supported on the inner step surface of the clamping body. The hemispherical cover to be processed is fixed to the clamping body by bolts.

[0009] The outer stepped surface of the clamping body is used to cooperate with the pressure plate and fix it on the workbench.

[0010] The auxiliary support is made of fiberglass material.

[0011] (III) Beneficial Effects

[0012] Compared with the prior art, the present invention has the following beneficial effects: the setting of the auxiliary hemispherical fiberglass material support enhances the rigidity of the thin-walled hemispherical machine cover, reduces deformation during processing, and further improves product quality. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a thin-walled hemispherical shroud based on carbon fiber composite material;

[0014] Figure 2 For the clamping body;

[0015] Figure 3 As an auxiliary support structure;

[0016] Figure 4 This is a schematic diagram of a special fixture. Detailed Implementation

[0017] To make the objectives, contents, and advantages of this utility model clearer, the specific embodiments of this utility model will be described in further detail below with reference to the accompanying drawings and examples.

[0018] This embodiment provides a special fixture and clamping method for a thin-walled hemispherical carbon fiber composite material machine cover.

[0019] Taking the machining of a certain model of machine cover as an example, the diameter of the maximum outer circle of the machine cover is...

[0020] It has a straight edge with a height of 15mm and four M4 threaded holes evenly distributed around its four sides. Figure 1 As shown. Based on the structural characteristics of the machine cover, a special fixture is adopted. The straight edge is positioned and supported by the hemispherical inner wall. It is fixed by screws and four M4 threaded holes through a reverse pull method.

[0021] The fixture structure includes a fixture body 1, an auxiliary support body 2, and a locking component. The fixture body is a ring-shaped structure that is thinner at the top and thicker at the bottom, with stepped surfaces on both the inner and outer sides of its top. Multiple radial through holes are evenly distributed along the circumference of the upper and lower parts of the fixture body, and the outer walls of these through holes are flat. The auxiliary support body is a hemispherical structure made of fiberglass material, with a cylindrical section at its bottom and corresponding slots on its spherical outer surface. The positions of these slots correspond to the positions of the hemispherical machine cover to be processed. The bottom cylindrical section of the auxiliary support body is located inside the fixture body, and the two are fixed together by bolts.

[0022] The hemispherical cover to be processed is fastened to the top of the auxiliary support body, and its bottom is supported on the inner step surface of the clamping body. The hemispherical cover to be processed is fixed to the clamping body by bolts.

[0023] The outer stepped surface of the clamping body is used to mate with the pressure plate and fix it on the workbench.

[0024] Fixture body: tooling such as Figure 2 As shown, it is a ring-shaped structure with two steps (1, 2) in its inner circle. The diameter of the inner hole of step 1 is [missing information]. The depth is 15mm, serving as a positioning ring. At the center, centered on the top surface of the fixture, the outer circumference has two steps (3, 4). Four dots are formed on the circumference of the inner step 1. Evenly distribute through holes, and mill four planes on the outer circle of the holes for bolt clamping of the workpiece.

[0025] Auxiliary support structure: such as Figure 3 A hemispherical fiberglass support is installed on the clamping body, the diameter of which is the inner diameter of the machine housing. And pre-process the empty space in the area of ​​the machine cover to be processed to ensure that it does not affect normal processing.

[0026] Locking components: 4-M4 stainless steel bolts, 30mm in length, to lock the machine cover to the clamp.

[0027] Clamping method:

[0028] (1) Fix the outer circle and bottom surface of the fixture to the CNC machine tool clamping platform, and find the center of the circle to locate the machining coordinate system.

[0029] (2) When clamping, the outer surface of the bottom circumference of the hemispherical cover is in contact with step 1, with an installation gap of 0.05mm, to ensure that the clamping deformation after the workpiece is clamped is within 0.05mm. The bottom surface of the cover is in contact with the upper surface of step 2, and the auxiliary support is in contact with the inner wall of the cover, to ensure that the gap is not greater than 0.05mm. Use 4-M4 screws to fix the cover to the fixture.

[0030] (3) Tighten the four screws symmetrically and evenly using a torque wrench, setting the tightening torque to 2.2 Nm. Control the tightness of the machine cover and fixture to ensure stable clamping and prevent loosening or deformation during processing. The combination state of the parts, fixture, and clamping bolts is as follows: Figure 4 As shown.

[0031] The advantages of this utility model are:

[0032] 1. The fixture provided by this utility model has a compact and reasonable structure, which can effectively solve the problems of clamping difficulties and easy deformation of thin-walled hemispherical machine covers during the processing.

[0033] 2. The precise positioning and stable clamping of the thin-walled hemispherical cover are achieved through the cooperation of the positioning steps and locking components.

[0034] 3. The auxiliary hemispherical fiberglass material support enhances the rigidity of the thin-walled hemispherical cover, reduces deformation during processing, and further improves product quality.

[0035] 4. Set the torque wrench to a reasonable torque, tighten the screws symmetrically and evenly, ensure the tightness of the machine cover and the fixture, quick workpiece clamping, consistent workpiece positioning and clamping status, and improve the first-pass yield.

[0036] 5. This utility model can effectively control the clamping and processing deformation of thin-walled hemispherical carbon fiber composite material machine covers, and has high application value. At present, it has been successfully applied to the processing of machine covers of a certain product and has achieved good results. It has also provided some reference for the processing of other thin-walled hemispherical parts.

[0037] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A special fixture for a thin-walled hemispherical carbon fiber composite material cowling, characterized by, The fixture includes a clamping body and an auxiliary support. The clamping body is a ring-shaped structure that is thinner at the top and thicker at the bottom, with stepped surfaces on both the inner and outer sides of its top. Multiple radial through holes are evenly arranged along the circumference of the upper and lower parts of the clamping body, and the outer wall surface of the through holes is set as a plane. The auxiliary support is a hemispherical structure with a cylindrical section at its bottom and corresponding slots on its spherical outer surface. The position of the slots is consistent with the position to be processed of the hemispherical machine cover. The bottom cylindrical section of the auxiliary support is set inside the clamping body, and the two are fixed by bolts.

2. The special fixture for the thin-walled hemispherical carbon fiber composite material cowl of claim 1, wherein, The hemispherical cover to be processed is fastened to the top of the auxiliary support body, and its bottom is supported on the inner step surface of the clamping body. The hemispherical cover to be processed is fixed to the clamping body by bolts.

3. The special clamp for the thin-walled hemispherical carbon fiber composite material machine cover as described in claim 1, characterized in that, The outer stepped surface of the clamp body is used to mate with the pressure plate and fix it on the workbench.

4. The special clamp for the thin-walled hemispherical carbon fiber composite material machine cover as described in claim 1, characterized in that, The auxiliary support is made of fiberglass material.

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