A device and method for testing the axial angle precision of a precision drilled counterbore

Abstract

The application discloses a kind of precision hole counterbore axis angle precision testing device and testing method, it is related to aviation manufacturing field, comprising: elastic fixed shaft assembly, fixed shaft body has radial elasticity and with the elastic interference fit of the shaft hole to be measured, fixed shaft body is evenly provided with multiple openings along the circumference, and the end of shaft measuring rod is connected with fixed shaft body away from the shaft hole;Counterbore measurement piece, including the taper abutting portion for being positioned with the counterbore inner wall surface and the detection portion connected with the side of the abutting portion away from the counterbore, the first reflection zone and the second reflection zone are used to reflect detection beam, the detection beam is projected to the scale area after being reflected in the first reflection zone, the second reflection zone in turn, and form light spot, and the light spot is used to enlarge and reflect the angle precision deviation of the counterbore.Using the above scheme, realize the quick, accurate detection of precision hole counterbore axis angle precision in assembly site.

Description

Technical Field

[0001] This invention relates to the field of aerospace manufacturing technology, and in particular to a device and method for inspecting the angular accuracy of a precision countersink. Background Technology

[0002] In modern aircraft manufacturing, large structural components are generally assembled using mechanical connections. Among these, the countersunk conical structure is one of the most common connection methods, widely used in aircraft fuselage skins and high-load-bearing components. Because these components operate under high loads, strong vibrations, and complex aerodynamic environments throughout their service life, the geometric accuracy of the connection points directly affects structural strength, sealing performance, and fatigue life. In particular, the machining quality of the hole-making and countersunk processes is a key factor determining the reliability of the connection. The accuracy of the countersunk axis angle is a core control indicator recognized in the industry; therefore, all OEMs impose strict tolerance requirements on geometric parameters such as concentricity and axis angle.

[0003] To ensure the accuracy of countersink angles, the industry currently relies primarily on coordinate measuring machines (CMMs) for inspection. While this equipment can meet accuracy requirements under static laboratory conditions, as a large-scale precision measuring instrument, it is costly, has strict environmental requirements, and complex operating procedures, making it unsuitable for direct inspection on the assembly line. This is especially true during the assembly of large, integral structural components, where the workpieces are large, have complex orientations, and involve tight workflows, making it difficult to frequently move the components to the CMM environment for inspection. Furthermore, CMM involves multiple steps such as workpiece positioning, probe path planning, and data fitting, resulting in long single-hole inspection cycles. This increasingly exposes its inadequacy in the high-speed assembly line environment where production cycles are critical.

[0004] As the size of aircraft structural components and the number of holes continue to increase, traditional methods of inspecting countersunk angle accuracy using coordinate measuring machines (CMMs) are insufficient to meet the requirements of mass assembly production. More critically, there is currently a lack of technical means to rapidly and in-situ detect countersunk angle errors at the assembly site, making real-time feedback and correction of hole quality impossible during production, thus posing a risk of misjudgment. Furthermore, the geometric characteristics of countersunk structures make their inspection difficult and require stringent accessibility; traditional equipment struggles to reliably acquire angle characteristics in confined spaces and on complex curved surfaces. Therefore, how to achieve rapid, low-cost, and on-site inspection of countersunk angle accuracy without relying on large measuring equipment has long been a technical challenge that has remained unresolved in the field of aerospace precision manufacturing. Summary of the Invention

[0005] The purpose of this invention is to provide an inspection device and method for the angular accuracy of the axis of a precision countersink, in order to solve the technical problem that the angular accuracy of the axis of a precision countersink cannot be quickly and accurately detected on the assembly site in the prior art.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] In a first aspect, a device for inspecting the axial angle accuracy of a precision countersunk hole is provided. The countersunk hole includes a countersunk hole and a shaft hole that are interconnected. The diameter of the countersunk hole gradually decreases along the direction close to the shaft hole, including:

[0008] An elastic fixed-axis assembly includes a fixed-axis body and a shaft measuring rod. The fixed-axis body has radial elasticity and is elastically interference-fitted with the shaft hole to be measured. The fixed-axis body has a plurality of openings evenly distributed in the circumferential direction. The openings extend along the axis of the fixed-axis body. The shaft measuring rod is connected to the end of the fixed-axis body opposite to the shaft hole.

[0009] The countersunk shaft measuring component includes a tapered abutment portion for fitting and positioning against the inner wall surface of the countersunk hole, and a detection portion connected to the side of the abutment portion away from the countersunk hole. The end face of the detection portion is provided with a first reflective area arranged in a ring and a scale area arranged around the first reflective area.

[0010] An adjustable optical measurement assembly includes a mounting plate coaxially arranged with the isometric rod and a light source fixed on the mounting plate. The light source is used to emit a detection beam at a fixed non-zero angle with the axis of the mounting plate. The mounting plate is provided with a second reflection area.

[0011] The first and second reflection areas are used to reflect the detection beam. The detection beam is reflected sequentially by the first and second reflection areas and then projected onto the scale area to form a light spot. The light spot is used to magnify and reflect the angular accuracy deviation of the counterboring hole.

[0012] Furthermore, there are multiple light sources, which are distributed at equal angular intervals along the circumference of the mounting plate.

[0013] Furthermore, an adjusting bushing is provided between the mounting plate and the detection unit, the adjusting bushing being fitted onto the outside of the isometric rod, and the height of the adjusting bushing is adjustable.

[0014] Furthermore, the elastic fixed-axis assembly also includes a deformation control component, which is disposed within the fixed-axis body and is used to control the fixed-axis body to maintain axial accuracy during deformation.

[0015] Furthermore, the fixed shaft body has multiple control holes, the axis of which is perpendicular to the axis of the fixed shaft body. The deformation control component includes multiple rigid rods, the rigid rods having a hardness greater than that of the fixed shaft body, and the length of each rigid rod matching the inner diameter of the shaft hole.

[0016] Furthermore, the fixed-axis body includes a coaxially arranged isometric part and bushing part, the isometric part is threadedly connected to the bushing part, the rigid rod is fixedly connected to the isometric part, and a plurality of control holes are formed on the isometric part;

[0017] When the bushing is elastically compressed, the rigid rod can extend out of the control hole and abut against the inner wall of the shaft hole.

[0018] Furthermore, a shrinkage hole is provided axially at one end of the fixed shaft body away from the abutment portion, and the shrinkage hole is coaxial with the axis of the fixed shaft body.

[0019] Furthermore, the scale area has a ring-shaped structure, including a first out-of-tolerance area, a qualified area, and a second out-of-tolerance area arranged radially from the inside to the outside.

[0020] Furthermore, the mounting plate is rotatable about the axis of the isometric rod.

[0021] Secondly, a method for inspecting the angular accuracy of the axis of a precision countersink is provided, utilizing the aforementioned device for inspecting the angular accuracy of the axis of a precision countersink, comprising the following steps:

[0022] Select a matching elastic fixed shaft body according to the diameter of the shaft hole to be measured, and connect the shaft measuring rod to the elastic fixed shaft body; insert the elastic fixed shaft body into the shaft hole, and use radial elastic expansion to make the elastic fixed shaft body and the shaft hole interference fit, ensuring that the axis of the shaft measuring rod and the shaft hole coincide;

[0023] Insert the shank measuring piece from the top of the shank measuring rod, so that the conical surface of the abutment faces the countersink;

[0024] The mounting plate is fitted onto the isometric rod;

[0025] Press the measuring component of the countersunk shaft to make the conical surface of the contact part completely fit with the inner wall of the countersunk hole;

[0026] The light source is turned on, and the detection beam is reflected sequentially through the first reflection area of ​​the countersunk shaft measuring component and the second reflection area of ​​the mounting plate, and then projected onto the scale area of ​​the detection part to form a light spot. The position of the light spot on the scale area is observed, and the angle accuracy deviation of the countersunk hole is judged based on the position of the light spot.

[0027] The beneficial effects of the inspection device and method for the accuracy of the axis angle of a precision countersunk hole provided by this invention are as follows: Through the synergistic configuration of the elastic fixed-axis assembly, the countersunk hole measuring component, and the adjustable optical measuring component, high-sensitivity, visualized, and magnified detection of the countersunk hole axis angle deviation is achieved. First, the fixed-axis body in the elastic fixed-axis assembly has axial openings uniformly arranged circumferentially, giving it controllable radial elasticity and forming a stable elastic interference fit with the shaft hole. After insertion into the shaft hole, it can automatically locate and approximate the true center axis of the shaft hole, thus accurately replicating the shaft hole direction and solving the problem of achieving high-precision centering and positioning on the assembly site. Second, the countersunk hole measuring component adopts a tapered abutment part consistent with the geometry of the countersunk hole. By achieving surface contact with the inner wall of the countersunk hole, the posture of the measuring component truly reflects the machining angle of the countersunk hole, fundamentally improving the problem of point contact being easily interfered with by local defects, leading to unstable angle judgment. The first reflection area and the outer scale area on the end face of the detection part form a reflection reference, which can directly affect the subsequent optical path changes due to the difference in the countersunk hole posture. Furthermore, the light source in the adjustable optical measurement assembly is arranged at a fixed non-zero angle. When the detection beam is continuously reflected by the first reflection area and the second reflection area on the mounting plate, any countersink angle error will change the angle relationship between the reflecting surfaces and be magnified multiple times during multiple reflections. This results in a measurable shift in the light spot projected onto the scale area, transforming the originally difficult-to-measure minute angle error into a significant displacement, achieving optical magnification and quantitative detection. Based on this structure, this invention eliminates the need for a coordinate measuring machine, enabling rapid, in-situ, and highly sensitive measurement of the countersink angle on the assembly site. This significantly improves the efficiency of hole quality feedback, reduces errors and costs caused by workpiece handling and complex measurement processes, and meets the demands of modern aerospace assembly for high-speed, high-stability on-site inspection capabilities. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of the precision-drilled countersink in an embodiment of the present invention;

[0029] Figure 2 This is a schematic diagram illustrating the concentricity deviation of the countersink in an embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram illustrating the tolerance of the axis angle in the countersink according to an embodiment of the present invention;

[0031] Figure 4 This is a schematic diagram of the overall structure of a device for inspecting the angular accuracy of a precision countersink hole according to an embodiment of the present invention;

[0032] Figure 5 This is a schematic diagram of the adjustable optical measurement component according to an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram of the structure of the elastic fixed-axis assembly according to an embodiment of the present invention;

[0034] Figure 7 This is a schematic diagram of the structure of the shank measuring component according to an embodiment of the present invention;

[0035] Figure 8 This is a schematic diagram of the scale area in an embodiment of the present invention.

[0036] Reference numerals: 1. Countersunk hole; 2. Shaft hole; 3. Elastic fixed shaft assembly; 31. Fixed shaft body; 311. Opening; 312. Shrinkage hole; 313. Control hole; 314. Shaft sleeve; 32. Shaft measuring rod; 33. Deformation control component; 4. Shaft measuring component; 41. Abutment part; 42. Detection part; 421. First reflection zone; 422. Scale area; 4221. First out-of-tolerance zone; 4222. Qualified zone; 4223. Second out-of-tolerance zone; 5. Adjustable optical measuring assembly; 51. Mounting plate; 511. Second reflection zone; 52. Light source; 521. Detection beam; 6. Adjusting shaft sleeve. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed after the word and its equivalents, but does not exclude other elements or objects.

[0038] In the field of modern aircraft manufacturing, large structural components are generally assembled using mechanical connections, with countersunk conical structures being one of the most common connection methods. Figure 1 As shown. The accuracy of countersinking is affected by two factors, including: the step-by-step hole-making process or system vibration during the hole-making process, etc. Its accuracy description includes two aspects: the concentricity of the axes of countersinking hole 1 and shaft hole 2, and the included angle between the axes, such as... Figure 2 and Figure 3 As shown. During the assembly process, the accuracy of the countersunk hole angle is a key quality control point. Therefore, each main manufacturer has strict requirements for the countersunk hole angle, such as: 1. The concentricity e between countersunk hole 1 and shaft hole 2 is within 0.076mm; 2. The axial angle tolerance θ between countersunk hole 1 and shaft hole 2 is ≤ ±1°.

[0039] Currently, the industry mainly relies on coordinate measuring machine (CMM) for inspecting the accuracy of countersinking in skin-forming parts. The specific process is as follows: First, pre-processing: Clean the surface of the part to be inspected, removing burrs, oil, and other impurities to avoid affecting measurement accuracy. Second, part fixation: Use the reference holes and positioning surfaces on the part to achieve precise positioning; the positioning error must be controlled within 0.02mm. Third, path planning: The operator imports the structural model into the measurement software, selects the countersinking area, and plans the movement path of the measuring probe. Fourth, data acquisition: The measuring probe contacts the inclined surface of countersinking hole 1 and the surface of shaft hole 2 according to the planned path, collecting three-dimensional coordinate data of at least 1 feature points on each surface. Fifth, data analysis: Fit the axis of shaft hole 2 and the axis of countersinking hole 1 based on the collected point coordinate data, and calculate the concentricity and axis angle tolerance. Existing methods have the following drawbacks: High inspection cost: Using a CMM for inspecting the accuracy of countersinking is costly in terms of equipment, personnel, and time. Low inspection efficiency: Coordinate measuring machines (CMMs) require multiple manual interventions (such as fixture installation and path planning), with each inspection taking 10-30 minutes. A single assembly of an aircraft skin requires thousands of holes and countersinks. If all inspections were done using CMMs, multiple machines would be needed, extending the production cycle and making it difficult to adapt to mass production schedules. Lack of in-situ inspection capability: CMMs are typically used for pre-production testing and hole quality inspection. Their accessibility cannot meet the in-situ inspection needs of the production site.

[0040] The following is in conjunction with the appendix Figure 4 - Appendix Figure 8 The specific embodiments of the present invention will be further described in detail below.

[0041] Reference Figures 4-8 An inspection device for the axial angle accuracy of a precision countersunk hole is mainly used to quickly and intuitively evaluate the axial angle deviation of the countersunk hole, including the countersunk hole 1 and the shaft hole 2, during the precision drilling process. The inspection device comprises an elastic axis-fixing assembly 3, a hole-axis measuring component 4, and an adjustable optical measuring assembly 5. Each component constructs a geometric reference chain around the shaft hole 2 and the countersunk hole 1 to be measured. A reflective optical magnification structure is used to form a light spot shift, enabling a visual and quantitative determination of the angular deviation between the axis of the countersunk hole 1 and the axis of the shaft hole 2. The countersunk hole described in this invention consists of interconnected countersunk holes 1 and shaft holes 2, wherein the diameter of the countersunk hole 1 gradually decreases along the direction approaching the shaft hole 2 to form a typical countersunk head connection structure used in aerospace applications.

[0042] In some specific embodiments of the present invention, the elastic fixed-axis assembly 3 is used to provide a stable and repeatable axial positioning reference for the shaft hole 2. The elastic fixed-axis assembly 3 includes a fixed-axis body 31 and a measuring rod 32 connected to one end thereto. The fixed-axis body 31 is made of a material with a controllable elastic modulus, and its outer diameter is slightly larger than the size of the shaft hole 2 to be measured. It achieves an elastic interference fit through radial elastic deformation. In order to improve the uniformity of radial deformation, the fixed-axis body 31 is uniformly provided with a plurality of openings 311 along the circumference. Each opening 311 extends along the axial direction of the fixed-axis body 31, so that the fixed-axis body 31 can effectively shrink radially when inserted into the shaft hole 2, thereby automatically finding and approaching the true central axis of the shaft hole 2, thus realizing adaptive approximation and reproduction of the central axis of the shaft hole 2. The measuring rod 32 is located at the end of the elastic fixed axis away from the shaft hole 2, and its axis is coaxial with the fixed-axis body 31. It is used as the installation reference for the subsequent optical detection assembly, so that the optical detection path is consistent with the true axis of the shaft hole 2.

[0043] In some embodiments of the present invention, the countersunk hole measuring component 4 is used to fit against the geometric surface of the countersunk hole 1 and capture the actual machining posture of the countersunk hole 1. The countersunk hole measuring component 4 includes a tapered abutment portion 41 for fitting against the inner wall of the countersunk hole 1. The tapered angle of the abutment portion 41 is machined according to the design angle of the countersunk hole 1, and stable and reliable positioning is achieved through surface contact. The side of the abutment portion 41 opposite to the countersunk hole 1 is connected to a detection portion 42. The end face of the detection portion 42 is provided with a first reflective area 421 arranged in a ring, and a scale area 422 is further provided on its outer side. The deviation of the axis of the countersunk hole 1 is indicated by the position of the reflected light spot landing on the scale area 422. In a preferred embodiment of the present invention, the scale area 422 adopts a ring structure, and a first out-of-tolerance area 4221, a qualified area 4222, and a second out-of-tolerance area 4223 are arranged radially from the inside to the outside, so that the angular deviation can be presented in a visual manner, allowing the operator to determine on-site whether the countersunk hole meets the assembly quality requirements.

[0044] In some other embodiments of the present invention, the adjustable optical measurement assembly 5 is mounted on the outside of the isometric rod 32 and arranged coaxially with the isometric rod 32, including a mounting plate 51 and a light source 52 fixedly mounted thereon. The light source 52 is used to emit a detection beam 521 that forms a fixed non-zero angle with the axis of the mounting plate 51, so that the beam can be angularly sensitive to the attitude of the countersunk hole 1. The mounting plate 51 is provided with a second reflection area 511, which forms an optical reflection path with the first reflection area 421. When the detection beam 521 emitted by the light source 52 is reflected sequentially by the first reflection area 421 and the second reflection area 511, it is finally projected onto the scale area 422 on the end face of the detection part 42, thereby forming a light spot in the scale area 422. Since a small deviation in the axis of the countersunk hole 1 will cause a change in the attitude of the first reflection area 421, the small angular error is amplified by a factor of two through the dual reflection path, so that the displacement of the light spot on the scale area 422 is within the readable range, significantly improving the detection sensitivity.

[0045] In some other embodiments of the present invention, the light source 52 may be configured as multiple sources, and distributed at equal angular intervals along the circumference of the mounting plate 51. The multi-light source 52 structure can form multiple light spots in the scale area 422, enabling the device to perform cross-verification of angular deviations at multiple positions of the countersink 1, thereby improving the reliability of the detection.

[0046] In some other embodiments of the present invention, to adapt to the position of the countersunk hole 1 under different depths and different workpiece assembly spaces, an adjusting bushing 6 is provided between the mounting plate 51 and the detection unit 42. The adjusting bushing 6 is sleeved on the outside of the isometric rod 32, and its height is adjustable, so that the mounting plate 51 relative to the detection unit 42 can be continuously or finely adjusted in the axial direction. By adjusting the axial position, the relative distance between the two reflecting surfaces can be changed, so that the optical path length, reflection angle, and the projection position of the light spot in the scale area 422 meet the detection requirements of different structural parts, thereby improving the adaptability of the device to different types of countersunk holes.

[0047] To enhance the repeatability and ease of operation of the adjustment, in a preferred embodiment, the adjustment bushing 6 can be a standardized bushing with various calibrated lengths to achieve quick replacement; different bushings are installed through standard threads, slots or step positioning structures, so that the reflective surface spacing can be switched with known step amounts, which is suitable for rapid batch testing of different countersink sizes.

[0048] In some other optional embodiments of the present invention, the adjustable structure of the adjusting bushing 6 can also be achieved by a differential screw mechanism, an elastically preloaded sliding sleeve structure, or an embedded wedge-shaped inclined surface mechanism. The differential screw mechanism can provide higher axial adjustment accuracy; the sliding sleeve structure can adapt to frequent adjustment scenarios; the wedge-shaped inclined surface structure can achieve short-stroke, high-magnification axial adjustment in space-constrained environments, further improving the operability of the device under complex working conditions.

[0049] In some specific embodiments of the present invention, to further improve the axial stability of the elastic fixed-axis assembly 3 during deformation, the elastic fixed-axis assembly 3 further includes a deformation control element 33. The deformation control element 33 is disposed inside the fixed-axis body 31 and is used to suppress the axial displacement or torsion generated by the fixed-axis body 31 during radial elastic contraction, thereby ensuring the stability of the alignment accuracy of the isometric rod 32. In some preferred embodiments, multiple control holes 313 are opened inside the fixed-axis body 31, the axis of the control holes 313 is perpendicular to the axis of the fixed-axis body 31, and multiple rigid rods are provided as deformation control elements 33. The rigid rods are made of metal or composite material with a hardness higher than that of the fixed-axis body 31, and their length matches the inner diameter of the shaft hole 2, so that when the fixed-axis body 31 is compressed, it can extend out of the control hole 313 and abut against the inner wall of the shaft hole 2, thereby providing reinforced support in a local area and limiting the radial deviation of the fixed-axis body 31. In order to make the support effect uniformly distributed, the rigid rods are preferably distributed at equal angles along the circumference, such as three-point 120° intervals, four-point 90° intervals, or more equal circumferential distribution. Equal-perimeter arrangement can reduce the possibility of uneven force distribution, and ensure that the fixed-axis body 31 maintains overall coaxiality when it contracts radially, thereby further improving the accuracy of axis reproduction.

[0050] In some embodiments of the present invention, the fixed-axis body 31 includes a coaxially arranged shaft measuring part and a bushing part 314, which are threadedly connected. A rigid rod is fixedly connected to the shaft measuring part, and a plurality of control holes 313 are formed on the shaft measuring part. When the insertion force increases, the bushing part 314 is elastically compressed, and the rigid rod extends out of the control holes 313 and forms support with the inner wall of the shaft hole 2, so that the elastic fixed-axis assembly 3 can maintain a stable shaft alignment effect under different shaft hole 2 dimensional errors and different insertion forces.

[0051] In some other embodiments of the present invention, in order to improve the overall flexibility of the fixed shaft body 31, a contraction hole 312 is provided axially at one end of the fixed shaft body 31 away from the abutment portion 41. The contraction hole 312 is arranged coaxially with the fixed shaft body 31, which can reduce the radial stiffness of this end, so that the fixed shaft body 31 can be inserted into the shaft hole 2 more smoothly during assembly, and improve the radial elastic interference fit characteristics.

[0052] In some embodiments of the present invention, the mounting plate 51 can rotate around the axis of the isometric rod 32 to achieve reflection measurements in different directions by adjusting the angle of the mounting plate 51 in scenarios where the number of light sources 52 is small or the measurement direction is limited. By changing the azimuth angle of the second reflection area 511 relative to the first reflection area 421, multi-directional optical paths can be formed, thereby achieving full circumferential detection of the axial error of the countersunk hole 1.

[0053] This rotary adjustment method not only expands the measurement direction coverage of the device, but also enables multi-directional angular deviation scanning without the need for an additional light source 52, thereby improving inspection efficiency. In practical use, the operator can quickly switch between multiple measurement directions by rotating the mounting plate 51 after a single installation, reducing repeated clamping and increasing the inspection cycle time.

[0054] In some alternative embodiments of the present invention, the materials, shapes, and processing methods of each component can be adjusted according to factors such as workpiece size, countersinking angle 1, and assembly space limitations. For example, the fixed-axis body 31 can be made of a composite material with adjustable elastic modulus, the tapered abutment part 41 can be adapted to countersinking holes 1 of different specifications by means of a replaceable tapered angle module, and the optical measurement component can also be replaced by a laser light source 52, a focusing optical element, or a photoelectric sensing structure. As long as the function of magnifying and displaying the angle deviation of the countersinking hole 1 is achieved, it is considered to fall within the protection scope of the present invention.

[0055] Secondly, a dynamic inspection method for a dual-arm robotic arm is provided, utilizing the aforementioned inspection device for the axial angle accuracy of a precision countersink, comprising the following steps:

[0056] In some embodiments, a matching elastic fixed-axis body 31 is first selected according to the actual diameter of the shaft hole 2 to be measured. The operator securely connects the shaft measuring rod 32 to the elastic fixed-axis body 31 through a threaded hole or sleeve structure, and slowly inserts the elastic fixed-axis body 31 into the shaft hole 2, causing its circumferential opening 311 structure to undergo radial elastic expansion under pressure, forming a stable elastic interference fit with the shaft hole 2. Through this process, the axis of the shaft measuring rod 32 automatically coincides with the actual axis of the shaft hole 2, realizing the establishment of the reference axis of the shaft hole 2, and providing a reliable reference for subsequent hole axis measurement.

[0057] Subsequently, the countersunk shaft measuring piece 4 is inserted from the top of the shaft measuring rod 32, with the conical surface of its contact portion 41 facing the countersunk hole 1. In some embodiments, the inner diameter of the countersunk shaft measuring piece 4 is larger than the outer diameter of the shaft measuring rod 32, thereby maintaining a gap during insertion and avoiding interference with the hole shaft positioning effect. The operator slides the countersunk shaft measuring piece 4 axially to an appropriate position from the countersunk hole inlet, so that it is in a state that can fit the countersunk hole but is not pressed tightly.

[0058] In the next step, according to the testing requirements, the mounting plate 51 is fitted onto the isometric rod 32. The mounting plate 51 is inserted from the top of the isometric rod 32, so that its lower end fits tightly against the upper surface of the adjusting sleeve 6. The mounting plate 51 and the isometric rod 32 maintain a sliding fit. It is equipped with a light source 52 (such as a laser lamp) and a reflective surface facing a fixed angle. The emission direction of the light source 52 is preset so that the beam can accurately illuminate the first reflective area 421 of the isometric measuring component 4. At this stage, the operator needs to confirm that the mounting plate 51 is not stuck and ensure that the optical path direction is stable.

[0059] In some other embodiments, an adjusting sleeve 6 is provided between the mounting plate 51 and the detection unit 42. The calibrated length L of the adjusting sleeve 6 (e.g., L=200mm) is selected from a preset standard part, and its lower end is in close contact with the top end face of the isometric measuring component 4, so that the distance between the first reflection area 421 of the isometric measuring component 4 and the second reflection area 511 of the mounting plate 51 is fixed at this calibrated length. This distance determines the transmission path of light in the two reflection processes, thereby affecting the final projection position of the light spot on the scale area 422, causing the angular deviation to be amplified by the optical path, which is equivalent to extending the length of the isometric rod 32.

[0060] After the aforementioned components are installed in sequence, during testing, the countersunk shaft measuring component 4 is gently pressed downwards to ensure that the conical surface of its contact portion 41 is in surface contact with the inner wall of the countersunk hole 1, thus guaranteeing that the axis of the countersunk shaft measuring component 4 is completely aligned with the axis of the countersunk hole. After the light source 52 is turned on, the beam first illuminates the first reflection area 421 and undergoes a first reflection, then it shines on the second reflection area 511 of the mounting plate 51 and undergoes a second reflection, finally projecting onto the scale area 422 at the top of the detection unit 42. Because the distance between the two reflective surfaces is precisely limited by the calibrated length of the adjusting bushing 6, the propagation path of the light between the reflections is effectively extended, causing the minute angular deviation of the countersunk hole axis to be magnified into an observable displacement at the light spot projection position. The operator observes the position of the light spot on the scale area 422. If the light spot falls within the preset qualified area 4222 (e.g., scale 3–6), it is determined that the countersink angle accuracy meets the design requirements. If the light spot deviates to the out-of-tolerance area, it indicates that the angle between the countersink axis and the shaft hole 2 axis exceeds the allowable range, and the hole-making process parameters or tooling need to be adjusted.

[0061] In some embodiments of the present invention, the position of the qualified area 4222 can be calculated by a theoretical optical path model, or an empirical calibration curve can be established by performing multiple measurements on a standard part, making the judgment basis more reliable. In an example applicable to drilling holes in aircraft skin, the diameter of the shaft hole 2 is φ8mm and the countersink angle tolerance is ±1°. When the angle deviation reaches the limit value, the light spot will obviously shift to the edge of the scale area 422 or even exceed the tolerance scale, thereby achieving intuitive judgment.

[0062] Through the above process, the inspection method of the present invention can not only complete the angle axis detection of a single countersink within 30-60 seconds, significantly improving inspection efficiency, but also achieve accurate judgment without relying on expensive instruments, making it suitable for integration into a batch hole-making production line for immediate sampling or full inspection.

[0063] This invention utilizes a lightweight optical magnification inspection mechanism comprised of an elastic fixed-axis assembly 3, a countersunk shaft measuring component 4, and an adjustable optical measuring component 5. This mechanism enables rapid, low-cost, and highly reliable inspection of the angular accuracy of countersunk shaft axes. Since the overall structure consists of only these core components, it eliminates the need for expensive equipment such as precision electronic angle sensing units, optical machine tool-type leveling modules, or coordinate measuring machines (CMMs). Therefore, the manufacturing and usage costs of the device are significantly reduced, with the inspection cost per hole decreasing from hundreds of yuan for traditional CMMs to less than one yuan. Furthermore, the inspection process of this invention eliminates the need for workpiece transfer and positioning, as well as equipment preheating, coordinate system reconstruction, or path planning. The inspection cycle time can be shortened to 30–60 seconds per hole, representing a 1–2 order of magnitude improvement in efficiency compared to the 10–30 minutes per hole required by CMMs. This makes it suitable for rapid, batch inspection of tens of thousands of holes in skin structures. Furthermore, since the overall length of this invention does not exceed 300mm, the device can directly extend into the narrow space of the assembly area, allowing for in-situ inspection immediately after drilling. This overcomes the application limitations of large coordinate measuring machines, which cannot approach aircraft or conduct inspections in confined spaces. Thanks to its operability without requiring specialized personnel, this invention not only significantly improves the inspection efficiency of large-scale assembly sites but also ensures the stability and accuracy of countersink angle detection results.

[0064] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations fall within the scope and spirit of the present invention. Furthermore, the present invention described herein may have other embodiments and can be implemented or carried out in various ways.

Claims

1. A device for inspecting the axial angle accuracy of a precision countersunk hole, wherein the countersunk hole comprises a countersunk hole and a shaft hole that are interconnected, the diameter of the countersunk hole gradually decreasing along the direction close to the shaft hole, characterized in that, include: An elastic fixed-axis assembly includes a fixed-axis body and a shaft measuring rod. The fixed-axis body has radial elasticity and is elastically interference-fitted with the shaft hole to be measured. The fixed-axis body has a plurality of openings evenly distributed in the circumferential direction. The openings extend along the axis of the fixed-axis body. The shaft measuring rod is connected to the end of the fixed-axis body opposite to the shaft hole. The countersunk shaft measuring component includes a tapered abutment portion for fitting and positioning against the inner wall surface of the countersunk hole, and a detection portion connected to the side of the abutment portion away from the countersunk hole. The end face of the detection portion is provided with a first reflective area arranged in a ring and a scale area arranged around the first reflective area. An adjustable optical measurement assembly includes a mounting plate coaxially arranged with the isometric rod and a light source fixed on the mounting plate. The light source is used to emit a detection beam at a fixed non-zero angle with the axis of the mounting plate. The mounting plate is provided with a second reflection area. The first and second reflection areas are used to reflect the detection beam. The detection beam is reflected sequentially by the first and second reflection areas and then projected onto the scale area to form a light spot. The light spot is used to magnify and reflect the angular accuracy deviation of the counterboring hole.

2. The device for inspecting the axial angle accuracy of a precision countersink as described in claim 1, characterized in that, There are multiple light sources, which are distributed at equal angular intervals along the circumference of the mounting plate.

3. The device for inspecting the axial angle accuracy of a precision countersink as described in claim 1, characterized in that, An adjusting bushing is provided between the mounting plate and the detection unit. The adjusting bushing is sleeved outside the isometric rod, and the height of the adjusting bushing is adjustable.

4. The device for inspecting the axial angle accuracy of a precision countersink as described in claim 1, characterized in that, The elastic fixed-axis assembly also includes a deformation control component, which is disposed within the fixed-axis body and is used to control the fixed-axis body to maintain axial accuracy during deformation.

5. The device for inspecting the axial angle accuracy of a precision countersink as described in claim 4, characterized in that, The fixed shaft body has multiple control holes, the axis of which is perpendicular to the axis of the fixed shaft body. The deformation control component includes multiple rigid rods, the rigid rods having a hardness greater than that of the fixed shaft body, and the length of each rigid rod matching the inner diameter of the shaft hole.

6. The device for inspecting the axial angle accuracy of a precision countersink as described in claim 5, characterized in that, The fixed-axis body includes a shaft measuring part and a bushing part arranged coaxially. The shaft measuring part and the bushing part are threadedly connected. The rigid rod is fixedly connected to the shaft measuring part. A plurality of control holes are formed on the shaft measuring part. When the bushing is elastically compressed, the rigid rod can extend out of the control hole and abut against the inner wall of the shaft hole.

7. The device for inspecting the axial angle accuracy of a precision countersink as described in claim 1, characterized in that, The fixed shaft body has a shrinkage hole along the axial direction at one end away from the abutment part, and the shrinkage hole is coaxial with the axis of the fixed shaft body.

8. The device for inspecting the angular accuracy of the axis of a precision countersink as described in claim 1, characterized in that, The scale area is a ring-shaped structure, including a first out-of-tolerance area, a qualified area, and a second out-of-tolerance area arranged radially from the inside to the outside.

9. The device for inspecting the axial angle accuracy of a precision countersink as described in claim 1, characterized in that, The mounting plate is rotatable about the axis of the isometric rod.

10. A method for inspecting the angular accuracy of a precision countersinking die axis, utilizing the inspection device for the angular accuracy of a precision countersinking die axis as described in any one of claims 1-9, characterized in that... Includes the following steps: Select a matching elastic fixed shaft body according to the diameter of the shaft hole to be measured, and connect the shaft measuring rod to the elastic fixed shaft body; insert the elastic fixed shaft body into the shaft hole, and use radial elastic expansion to make the elastic fixed shaft body and the shaft hole interference fit, ensuring that the axis of the shaft measuring rod and the shaft hole coincide; Insert the shank measuring piece from the top of the shank measuring rod, so that the conical surface of the abutment faces the countersink; The mounting plate is fitted onto the isometric rod; Press the measuring component of the countersunk shaft to make the conical surface of the contact part completely fit with the inner wall of the countersunk hole; The light source is turned on, and the detection beam is reflected sequentially through the first reflection area of ​​the countersunk shaft measuring component and the second reflection area of ​​the mounting plate before being projected onto the scale area of ​​the detection unit to form a light spot. The position of the light spot on the scale area is observed, and the angle accuracy deviation of the countersunk hole is determined based on the position of the light spot.

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