Machining method for counter bore of ceramic matrix composite curvature component

Abstract

The invention provides a machining method for a counter bore of a ceramic matrix composite curvature component. The machining method mainly solves the technical problem that according to an existing machining method, a new thread in the counter bore is prone to being abraded and even losing efficacy. The method comprises the following steps: 1, determining the number of counter bores in the curvature component and the position and the size of each counter bore according to assembly requirements; 2, according to the size, determined in the step 1, of the counterbore, a corresponding counterbore bottom hole is formed in the corresponding position, and allowance is reserved; 3, a reamer is used for conducting finish machining on the countersunk bottom hole, and a corresponding threaded hole is formed in the countersunk bottom hole; 4, taper grinding rods of corresponding specifications are selected; 5, a taper grinding rod is adopted to machine a taper hole with an upward opening in the upper portion of each threaded hole, and a counterbore semi-finished product is obtained; 6, the countersunk process screw is adopted for trial matching of the countersunk hole semi-finished product, whether the countersunk hole semi-finished product meets the preset process requirement or not is confirmed, and if yes, machining of the countersunk hole is completed; and if not, machining is continued until machining of the counterbore is completed.

Description

Technical Field

[0001] The invention relates to a method for processing a countersunk hole, in particular to a method for processing a countersunk hole of a ceramic-based composite material curvature component. Background Art

[0002] Ceramic-based composites are a new type of material that integrates the performance advantages of metal materials, ceramic materials and carbon materials. They have the characteristics of high temperature resistance, low density, high specific strength, high specific modulus, oxidation resistance, ablation resistance, insensitivity to cracks, and no catastrophic damage. They are currently widely used in machinery, aerospace, nuclear, energy and other fields.

[0003] As part of the appearance of the corresponding product, the ceramic-based composite curvature component is generally connected and fixed to the main body of the product through countersunk screws. Therefore, in the design process of the curvature component, the position of the countersunk hole and the processing quality are particularly important. Usually, there are a large number of countersunk holes on the ceramic-based composite curvature component. The traditional method mostly uses manual hole making and tapping, and then the countersunk screws are tried after the tapping is completed to verify the processing quality and accuracy of the countersunk hole. However, in this process, due to multiple installation and removal of the countersunk screws, the newly made threads in the countersunk hole are easily worn or even fail. Therefore, there is an urgent need for a processing method for the countersunk holes of ceramic-based composite components to reduce or avoid the occurrence of such problems. Summary of the invention

[0004] The purpose of the present invention is to solve the technical problem that the existing processing method easily causes the newly made thread in the countersunk hole to be worn or even fail, and to provide a processing method for the countersunk hole of a ceramic-based composite material curvature component.

[0005] To achieve the above objectives, the technical solutions provided by the present invention are:

[0006] A method for processing a countersunk hole of a ceramic matrix composite material curvature component is special in that it comprises the following steps:

[0007] Step [1], determining the number of countersunk holes on the curvature component, as well as the position and size of each countersunk hole according to assembly requirements; the curvature component is a ceramic matrix composite curvature component; the countersunk hole is a stepped hole, the lower portion of which is a threaded hole, and the upper portion is a tapered through hole with the larger end facing outward;

[0008] Step [2], according to the number, position and size of the countersunk holes determined in step [1], corresponding countersunk bottom holes are respectively made at corresponding positions, and radial allowances are left;

[0009] Step [3]: Use a reamer to finish-process each countersunk bottom hole to remove excess, and use a tap to make corresponding threaded holes in each countersunk bottom hole;

[0010] Step [4]: ​​According to the sizes of the countersunk holes determined in step [1], select a taper grinding rod of corresponding specifications;

[0011] Step [5], using a tapered grinding rod, respectively, on the upper part of each threaded hole obtained in step [3], a tapered hole with an opening facing upward is machined, and a radial allowance is left, thereby obtaining a semi-finished countersunk hole;

[0012] Step [6], using a countersunk screw to test fit the countersunk hole semi-finished product described in step [5], and confirm whether it meets the preset process requirements. If it does, then the processing of the countersunk hole is completed; if it does not, proceed to step [7];

[0013] Step [7], continue to process the tapered hole described in step [5] using a tapered grinding rod, and perform trial fitting and confirmation in the manner of step [6] until the countersunk hole meets the preset process requirements, thereby completing the processing of the countersunk hole.

[0014] Further, in step [6], the countersunk process screw includes a detection rod and a fixing seat;

[0015] The detection rod is a cylindrical structure, the diameter of which is smaller than the inner diameter of the threaded hole in the countersunk hole, and the length of which is consistent with the length of the threaded hole;

[0016] One end of the fixing seat is a cone structure, and the other end is a plane structure, wherein the small end of the cone structure is coaxially connected to the detection rod, and the cone structure is consistent with the theoretical values ​​of the taper and size of the conical hole in the countersunk hole.

[0017] Furthermore, the countersunk process screw also includes a hand-held rod, which is a cylindrical structure and is vertically connected to the planar structure at one end of the fixing base away from the detection rod, and the diameter of the hand-held rod is smaller than the diameter of the planar structure.

[0018] Furthermore, the diameter tolerance of the detection rod is -0.10 to -0.05 mm; the length of the handheld rod is 5 to 10 mm.

[0019] Furthermore, the countersunk process screw is pre-fitted by means of a countersunk hole auxiliary piece, and the countersunk hole auxiliary piece is a block-shaped structure, and a countersunk process hole that is compatible with the structure and size of the countersunk process screw is provided on the top thereof.

[0020] Furthermore, in step [6], the preset process requirement is that after the countersunk process screw is installed in the countersunk hole, the upper surface of the planar structure of the fixing seat in the countersunk process screw is flush with the upper surface of the curvature component where the countersunk hole is located, or is 0.1 to 0.2 mm lower than the upper surface of the curvature component where the countersunk hole is located.

[0021] Furthermore, in step [2], the countersunk bottom hole is prepared using a handheld pneumatic drill and a matching glass drill.

[0022] Furthermore, in step [2], the margin is 0.1 to 0.3 mm.

[0023] Furthermore, in step [3], the hole diameter tolerance of the countersunk bottom hole after fine machining is 0 to +0.1 mm.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention first determines the position, quantity and size of the countersunk holes, then processes the countersunk bottom holes, then processes threaded holes and tapered holes in the countersunk bottom holes in sequence, and finally uses countersunk process screws to test-fit the countersunk hole semi-finished products to confirm whether they meet the process requirements. This method does not require the use of composite countersunk screws for test fitting, thereby avoiding damage to the threads in the countersunk holes caused by repeated disassembly of the composite countersunk screws during test fitting, thereby improving the processing quality of the countersunk holes.

[0026] 2. The countersunk process screw of the present invention includes a detection rod and a fixing seat, wherein the detection rod is a cylindrical structure, and the fixing seat is adapted to the tapered hole structure in the countersunk hole. This design can not only avoid damage to the threads in the countersunk hole, but also verify whether the tapered hole meets the process requirements.

[0027] 3. The countersunk head process screw of the present invention also includes a hand-held rod, which facilitates the taking of the countersunk head process screw and further improves the efficiency of trial fitting and processing.

[0028] 4. The present invention can also pre-fit the countersunk process screws through the countersunk hole auxiliary parts, thereby ensuring that the process of the countersunk process screws meets the standard requirements, thereby improving the processing accuracy of the countersunk holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of a countersunk bottom hole made on a curvature component in an embodiment of the present invention.

[0030] Figure 2 It is a schematic structural diagram of a finished countersunk hole obtained by machining on a curvature component in an embodiment of the present invention.

[0031] Figure 3 It is a schematic diagram of the structure of a countersunk head screw in an embodiment of the present invention.

[0032] Figure 4 Schematic diagram of the structure of the countersunk hole auxiliary component in an embodiment of the present invention.

[0033] Figure 5 It is a schematic diagram of the state after the countersunk process screw and the countersunk hole auxiliary part are matched in an embodiment of the present invention.

[0034] Figure 6Schematic diagram of the state after the composite countersunk nail and the countersunk hole auxiliary component are matched in an embodiment of the present invention.

[0035] The reference numerals are as follows:

[0036] 1-countersunk process screw, 11-detection rod, 12-fixed seat, 13-handheld rod, 2-countersunk hole auxiliary part, 21-countersunk process hole, 3-composite countersunk nail. DETAILED DESCRIPTION

[0037] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0038] This embodiment provides a method for processing a countersunk hole of a ceramic matrix composite material curvature component, comprising the following steps:

[0039] Step [1]: Determine the number of countersunk holes on the curvature component, as well as the position and size of each countersunk hole according to assembly requirements. The curvature component described in this embodiment is a ceramic matrix composite curvature component; and the countersunk hole is a stepped hole, the lower part of which is a threaded hole, and the upper part is a tapered through hole with the large end facing outward.

[0040] Step [2]: According to the number, position and size of the countersunk holes determined in step [1], a handheld air drill and its matching glass drill are used to make corresponding countersunk bottom holes at corresponding positions, such as Figure 1 As shown, a radial margin of 0.1 to 0.3 mm is left.

[0041] Step [3]: Use a reamer to finish-process each countersunk bottom hole to remove the excess. After finishing, the hole diameter tolerance of the countersunk bottom hole is 0~+0.1mm. Then use a tap to make corresponding threaded holes in each countersunk bottom hole. At this point, the threaded holes meet the finished product requirements.

[0042] Step [4]: ​​According to the sizes of the countersunk holes determined in step [1], select a taper grinding rod of corresponding specifications.

[0043] Step [5], using a tapered grinding rod, respectively, on the upper part of each threaded hole obtained in step [3], a tapered hole with the opening facing upward is machined, and an appropriate radial allowance is left (generally, an allowance is left when machining the tapered hole for the first time), thereby obtaining a countersunk hole semi-finished product.

[0044] Step [6], use the countersunk process screw 1 to test the countersunk hole semi-finished product obtained in step [5], and confirm whether it meets the preset process requirements. If it does, the countersunk hole processing is completed; if it does not, proceed to step [7].

[0045] Step [7], continue to process the tapered hole in step [5] using a tapered grinding rod, and perform trial fitting and confirmation in the manner of step [6] until the countersunk hole meets the preset process requirements, thereby completing the processing of the countersunk hole. The processed curvature component countersunk hole is as follows Figure 2 shown.

[0046] like Figure 3 As shown, the countersunk screw 1 described in this embodiment includes a detection rod 11 and a fixing seat 12; the detection rod 11 is a cylindrical structure, and its diameter is smaller than the inner diameter of the threaded hole in the countersunk hole, and the diameter tolerance is -0.10 to -0.05 mm; the length of the detection rod 11 is consistent with the length of the threaded hole. One end of the fixing seat 12 is a cone structure, and the other end is a plane structure, wherein the small end of the cone structure is coaxially connected to one end of the detection rod, and the cone structure is consistent with the theoretical value of the taper and size of the conical hole in the countersunk hole, and is also consistent with the cone structure and size of the composite countersunk nail 3 (i.e., the countersunk nail actually matched with the countersunk hole).

[0047] In order to improve the convenience of using the countersunk process screw 1, the countersunk process screw 1 also includes a hand-held rod 13. The hand-held rod 13 is a cylindrical structure, which is vertically connected to the planar structure of the fixing seat 12 away from the end of the detection rod 11, and the diameter of the hand-held rod 13 is smaller than the diameter of the planar structure, and the length is generally 5 to 10 mm.

[0048] Combination Figure 4 and Figure 5 As shown, in order to verify whether the countersunk screw 1 meets the requirements, this embodiment also provides a countersunk hole auxiliary part 2. The countersunk hole auxiliary part 2 is a block structure that can be processed by a CNC milling machine. The top of the countersunk hole auxiliary part 2 is provided with a countersunk process hole 21 that matches the structure and size of the countersunk process screw 1. The countersunk hole auxiliary part 2 is used to verify whether the countersunk process screw 1 meets the requirements. The requirement is generally that the step difference between the upper surface of the countersunk process screw 1 and the upper surface of the countersunk auxiliary part 2 is less than 0.1mm. At the same time, Figure 6 As shown, the countersunk process hole 21 (aperture tolerance +0.05 to +0.10) on the countersunk hole auxiliary part 2 is verified by the composite countersunk nail 3, that is, the step difference between the upper surface of the composite countersunk nail 3 and the upper surface of the countersunk hole auxiliary part 2 is less than 0.1 mm, thereby ensuring the accuracy of the size of the countersunk process screw 1 used for trial fitting.

[0049] In this embodiment, the preset process requirement when trial fitting the countersunk process screw 1 is that after the countersunk process screw 1 is installed in the countersunk hole, the upper surface of the planar structure of the fixing seat 12 in the countersunk process screw 1 is flush with the upper surface of the curvature component where the countersunk hole is located, or is 0.1 to 0.2 mm lower than the upper surface of the curvature component where the countersunk hole is located.

[0050] The required countersunk hole is obtained by processing in the above manner, and then the countersunk hole is trial-fitted with the matching composite countersunk nail 3. After the trial-fitting and installation are completed, CVI silicon carbide deposition and subsequent treatment are performed on the component.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for processing a countersunk hole of a ceramic matrix composite material curvature component, characterized in that: The following steps are involved: Step [1], determining the number of countersunk holes on the curvature component, as well as the position and size of each countersunk hole according to assembly requirements; the curvature component is a ceramic matrix composite curvature component; the countersunk hole is a stepped hole, the lower portion of which is a threaded hole, and the upper portion is a tapered through hole with the larger end facing outward; Step [2], according to the number, position and size of the countersunk holes determined in step [1], corresponding countersunk bottom holes are respectively made at corresponding positions, and radial allowances are left; Step [3]: Use a reamer to finish-process each countersunk bottom hole to remove excess, and use a tap to make corresponding threaded holes in each countersunk bottom hole; Step [4]: ​​According to the sizes of the countersunk holes determined in step [1], select a taper grinding rod of corresponding specifications; Step [5], using a tapered grinding rod, respectively, on the upper part of each threaded hole obtained in step [3], a tapered hole with an opening facing upward is machined, and a radial allowance is left, thereby obtaining a semi-finished countersunk hole; Step [6], using the countersunk process screw (1) to test fit the countersunk hole semi-finished product described in step [5], and confirm whether it meets the preset process requirements. If it meets the requirements, the processing of the countersunk hole is completed; if it does not meet the requirements, proceed to step [7]; Step [7], continue to process the tapered hole described in step [5] using a tapered grinding rod, and perform trial fitting and confirmation in the manner of step [6] until the countersunk hole meets the preset process requirements, thereby completing the processing of the countersunk hole.

2. The method for processing a countersunk hole of a ceramic matrix composite material curvature component according to claim 1, characterized in that: In step [6], the countersunk head process screw (1) comprises a detection rod (11) and a fixing seat (12); The detection rod (11) is a cylindrical structure, the diameter of which is smaller than the inner diameter of the threaded hole in the countersunk hole, and the length of which is consistent with the length of the threaded hole; One end of the fixing seat (12) is a cone structure, and the other end is a plane structure, wherein the small end of the cone structure is coaxially connected to the detection rod (11), and the cone structure is consistent with the theoretical values ​​of the taper and size of the conical hole in the countersunk hole.

3. The method for processing a countersunk hole of a ceramic matrix composite material curvature component according to claim 2, characterized in that: The countersunk process screw (1) further comprises a hand-held rod (13), which is a cylindrical structure and is vertically connected to a planar structure at one end of the fixing seat (12) away from the detection rod (11), and the diameter of the hand-held rod (13) is smaller than the diameter of the planar structure.

4. The method for processing a countersunk hole of a ceramic matrix composite material curvature component according to claim 3, characterized in that: The diameter tolerance of the detection rod (11) is -0.10 to -0.05 mm; The length of the handheld rod (13) is 5 to 10 mm.

5. The method for processing a countersunk hole of a ceramic matrix composite material curvature component according to claim 2, 3 or 4, characterized in that: The countersunk process screw (1) is pre-fitted by means of a countersunk hole auxiliary piece (2); the countersunk hole auxiliary piece (2) is a block-shaped structure, and a countersunk process hole (21) matching the structure and size of the countersunk process screw (1) is provided on the top thereof.

6. The method for processing a countersunk hole of a ceramic matrix composite material curvature component according to claim 5, characterized in that: In step [6], the preset process requirement is that after the countersunk process screw (1) is installed in the countersunk hole, the upper surface of the planar structure of the fixing seat (12) in the countersunk process screw (1) is flush with the upper surface of the curvature component where the countersunk hole is located, or is 0.1 to 0.2 mm lower than the upper surface of the curvature component where the countersunk hole is located.

7. The method for processing a countersunk hole of a ceramic matrix composite material curvature component according to claim 1, characterized in that: In step [2], the countersunk bottom hole is prepared using a handheld pneumatic drill and its matching glass drill.

8. The method for processing a countersunk hole of a ceramic matrix composite material curvature component according to claim 7, characterized in that: In step [2], the margin is 0.1 to 0.3 mm.

9. The method for processing a countersunk hole of a ceramic matrix composite material curvature component according to claim 8, characterized in that: In step [3], the hole diameter tolerance of the countersunk bottom hole after fine machining is 0 to +0.1 mm.

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