Threaded hole extension tolerance detection and C reference positioning device and method

Abstract

The invention provides a threaded hole extension tolerance detection and C reference positioning device and method. The device comprises a base, a positioning assembly and a detection assembly. The positioning assembly is used for realizing A and B reference positioning of the workpiece; the detection assembly comprises a first detection part, a second detection part, a positioning judgment part and a driving part. The first detection part is an extension tolerance detection rod and is detachably mounted in a threaded hole of a workpiece, and the end part of the first detection part is provided with a first conical structure; and the second detection part comprises an extension tolerance detection sleeve which is movably arranged, and a second conical structure matched with the first conical part is arranged on the extension tolerance detection sleeve. Whether the extension tolerance is qualified or not can be judged by driving the detection sleeve to move, combining the assembly of the detection sleeve and the detection rod and the preset action of the positioning judgment part, and after the extension tolerance is judged to be qualified, the driving part is utilized to drive the detection sleeve to enable the two conical structures to be tightly attached and self-centered, so that the extension tolerance detection and the accurate establishment of the C reference are synchronously completed.

Description

Technical Field

[0001] This invention relates to the field of testing equipment technology, and in particular to a device and method for detecting thread hole extension tolerance and C-datum positioning. Background Technology

[0002] In the fields of precision machining and assembly, the control of geometric dimensions and tolerances (GD&T) of parts is crucial. Among these, threaded holes, as a common connection feature, directly impact the overall functionality and reliability of the product due to their positional accuracy and assembly performance. To ensure smooth threaded connections, extended tolerances are often used on design drawings to define the positional requirements of threaded holes. Extended tolerances allow the tolerance zone to extend outward from the part surface by a specified length to simulate the actual effective mating length of a bolt or pin, thus more accurately reflecting assembly conditions. After welding nuts, the extended tolerance of the nuts needs to be inspected, and this extended tolerance is used as the C-datum for positioning. However, traditional extended tolerance inspection methods suffer from large deviations, poor accuracy, long inspection times, and high costs. More importantly, when the threaded hole extended tolerance entity is designated as the C-datum, even if the extended tolerance is acceptable, limitations such as part machining tolerances and fixture clearances can lead to inaccurate C-datum positioning, severely affecting the reliability of subsequent measurements relying on the C-datum. Summary of the Invention

[0003] This invention provides a device and method for detecting thread hole extension tolerance and positioning C-datum, which solves the technical problems that the inspection fixture cannot quickly and accurately detect thread hole extension tolerance within the production line cycle, and simultaneously establishes a stable and reliable C-datum for subsequent measurement.

[0004] This invention provides a device for detecting thread hole extension tolerance and positioning C-datum, comprising: Base; A positioning component, disposed on the base, is used for positioning the workpiece to be tested; A detection component is disposed on the base, the detection component comprising: The first detection part is detachably installed in the threaded hole on the workpiece, and the end of the first detection part is provided with a first tapered structure; The second detection unit is adapted to the structure of the first detection unit and configured to move along a preset path. The second detection unit includes a mating cavity for accommodating the first detection unit and a second conical structure that matches the first conical structure. The positioning determination unit is configured to determine whether the extension tolerance of the threaded hole is qualified based on whether the second detection unit can complete a predetermined action when the second detection unit moves to the detection position, and to perform initial positioning of the second detection unit after the determination is qualified. The driving unit is configured to, after the initial positioning, drive the second detection unit to displace relative to the first detection unit so that the second tapered structure and the first tapered structure are in close contact and self-centering fit, thereby establishing a positioning reference based on the threaded hole. In one embodiment of the present invention, the positioning component includes: A first positioning unit, the first positioning unit including an A reference positioning ring, for positioning the A reference of the product under test; The second positioning part includes a B reference positioning ring, which is configured to move relative to the base. An elastic ejector is provided inside the B reference positioning ring for applying an elastic force to the workpiece to make it conform to the first positioning part.

[0005] In one embodiment of the present invention, the positioning component further includes a contour limiting part, which is fixedly installed on the base. The contour limiting part includes a plurality of back plates, and a detection gap of predetermined width is formed between the positioning surface of each back plate and the theoretical contour surface of the workpiece.

[0006] In one embodiment of the present invention, the first detection part includes a connecting part that is threadedly connected to the threaded hole, and a mating part for forming a reference, wherein the first tapered structure is formed at the end of the mating part.

[0007] In one embodiment of the present invention, the connecting portion includes: The guide portion has a structure that is adapted to the open hole structure at the front end of the threaded hole, and its outer diameter is smaller than the minor diameter of the threaded hole. A threaded connection part, the threaded connection part having the same specifications as the threaded hole, and the first detection part being connected to the workpiece through the threaded connection part.

[0008] In one embodiment of the present invention, the second detection unit includes: A sliding mounting base is disposed on the base; An extended tolerance inspection sleeve is connected to the sliding mounting base, and the extended tolerance inspection sleeve can move linearly along the preset path on the base.

[0009] In one embodiment of the present invention, the positioning determination unit includes: Card slot, disposed on the base; A flap is rotatably connected to the second detection unit; The predetermined action is that the flap is inserted into the slot of the card holder, and there is an movable gap between the flap and the slot wall of the card holder.

[0010] In one embodiment of the present invention, the driving part includes a clamp, which is used to press the extended tolerance detection sleeve and make it continue to move forward after the second detection part completes the initial positioning.

[0011] In one embodiment of the present invention, the detection component further includes an anti-collision block, which is fixed on the base and used to limit the maximum stroke of the extended tolerance detection sleeve.

[0012] This invention also proposes a method for detecting thread hole extension tolerance and positioning C-datum, comprising: The first detection unit is installed in the threaded hole on the workpiece to be tested; The workpiece is positioned using a positioning component; The second detection unit moves along a preset path. If the first detection unit can be assembled with the second detection unit and the positioning determination unit can complete the predetermined action, then the extension tolerance of the threaded hole is determined to be qualified. After the qualification is determined, the second detection part is initially positioned by the positioning component, and the second detection part is further pushed by the driving part, so that the second conical structure of the second detection part is in close contact with the first conical structure of the first detection part and self-centering fits, thereby establishing the C reference; Based on the established C datum, the form and position tolerances of the workpiece are inspected.

[0013] The beneficial effects of the present invention are as follows: The thread hole extension tolerance detection and C-datum positioning device and method proposed in this invention materialize the extension tolerance zone through the extension tolerance detection bar, and achieve a seamless connection from tolerance detection to datum establishment through the movement and cooperation of the extension tolerance detection sleeve. It transforms the complex tolerance zone verification into an intuitive mechanical assembly action. A single operation can simultaneously complete the qualification judgment and accurate and stable C-datum positioning, which significantly improves the efficiency of extension tolerance detection and the stability and reliability of C-datum positioning, ensuring the accuracy and reliability of subsequent detection. Through the structure of the flap with gap and the card seat, the acceptance judgment and positioning preparation functions are integrated. It can work in conjunction with the extended tolerance inspection sleeve and the extended tolerance inspection bar to realize the intuitive judgment of tolerance acceptance, and also provides an adaptive stroke for subsequent clamping and positioning to ensure the final accuracy of the benchmark establishment. A stable multi-reference positioning system was constructed using positioning components, which effectively eliminated workpiece clamping gaps and posture sway, providing a reliable positioning basis for high-precision detection and ensuring the repeatability and accuracy of the detection results. By integrating contour limiting, assembly simulation and inspection functions into one platform, a comprehensive and efficient evaluation of the key dimensions and contours of the workpiece is achieved, which significantly improves the inspection efficiency and quality control level of the production line and effectively controls quality costs. This invention integrates thread hole extension tolerance detection, datum establishment, and product inspection through the coordinated operation of various components. It effectively solves problems such as low efficiency in extension tolerance detection and inaccurate datum establishment, and achieves significant improvements in detection accuracy, efficiency, and reliability. It can meet the comprehensive requirements of speed, accuracy, and cost control for mass production on production lines. Attached Figure Description

[0014] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0015] In the attached diagram: Figure 1 This is a schematic diagram of the overall structure of the thread hole extension tolerance detection and C-datum positioning device and the workpiece provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the overall structure of the thread hole extension tolerance detection and C-datum positioning device and the workpiece from another perspective, according to an embodiment of the present invention. Figure 3 This is a front view of the overall structure of the thread hole extension tolerance detection and C-datum positioning device and the workpiece provided in an embodiment of the present invention; Figure 4 This is a top view of the overall structure of the thread hole extension tolerance detection and C-datum positioning device and the workpiece provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the overall structure of a thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention. Figure 6 This is a schematic diagram of the base of a thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the structure of the first positioning part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 8 An exploded view of the first positioning part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the structure of the first positioning part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of the structure of the second positioning part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 11 An exploded view of the second positioning part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 12 This is a partial structural diagram of the second positioning part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention. Figure 13 This is a schematic diagram of the B reference positioning ring of a thread hole extension tolerance detection and C reference positioning device provided in an embodiment of the present invention; Figure 14 A cross-sectional view of the B reference positioning ring of a thread hole extension tolerance detection and C reference positioning device provided in an embodiment of the present invention; Figure 15 An exploded view of the first contour limiting part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 16 This is a schematic diagram of the structure of the second contour limiting part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 17 An exploded view of the second contour limiting part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 18 This is a schematic diagram of the structure of the second contour limiting part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 19 This is a schematic diagram of the third contour limiting part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention. Figure 20 An exploded view of the third contour limiting part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 21 A top view of the third contour limiting part of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 22 A schematic diagram of the assembly passability simulation detection unit of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 23 This is a schematic diagram of the overall structure of the detection component of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention. Figure 24 An exploded view of the detection component of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 25 This is a partial structural schematic diagram of the detection component of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 26 This is a schematic diagram of the structure of the first detection unit of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 27 This is a schematic diagram of the structure of the first detection unit of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention from another perspective. Figure 28 This is a front view of the first detection unit of a thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention. Figure 29 This is a schematic diagram of the extension tolerance detection sleeve of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention. Figure 30 The front view of the extension tolerance detection sleeve of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention; Figure 31 This is a schematic diagram of the assembly process of the extension tolerance detection sleeve and extension tolerance detection bar of the thread hole extension tolerance detection and C-datum positioning device provided in an embodiment of the present invention. Figure 32 This is a schematic diagram of the assembly structure of the extension tolerance detection sleeve and the extension tolerance detection bar when the extension tolerance inspection is qualified according to an embodiment of the present invention; Figure 33 This is a schematic diagram of the assembly structure of the thread hole extension tolerance detection sleeve and the extension tolerance detection bar when the C datum positioning device is completed, according to an embodiment of the present invention. Figure 34 This is a schematic diagram of the assembly structure of the extended tolerance inspection bar and the workpiece according to an embodiment of the present invention; Figure 35 This is a schematic diagram of the assembly structure of the extended tolerance inspection bar and the nut of the workpiece provided in an embodiment of the present invention; Figure 36 This is a schematic diagram of the assembly structure of the extended tolerance detection bar and the extended tolerance detection sleeve after being assembled with the workpiece nut according to an embodiment of the present invention. Figure 37 This is a flowchart illustrating a method for detecting threaded hole extension tolerance and positioning C-datum according to an embodiment of the present invention.

[0016] The attached figures are labeled as follows: 100. Base; 110. Base plate; 120. Handle; 130. Positioning reference; 140. Spare test piece mounting base; 150. Spare test piece; 200, Positioning component; 210, First positioning part; 220, Second positioning part; 230, First contour limiting part; 240, Second contour limiting part; 250, Third contour limiting part; 260, Assembly passability simulation detection part; 211. First bracket; 212. First fixed base; 213. First pad; 214. A reference positioning ring; 221. Second bracket; 222. Second fixed seat; 223. Sliding seat; 2231. Base; 2232. Push rod; 2233. Cover plate; 2234. Handle; 2235. Limit pin; 2236. Limit pin hole; 224. B reference positioning ring; 225. Elastic ejector; 2251. Spring; 2252. Push rod; 231. Third bracket; 232. Third fixing seat; 233. First positioning plate; 241. Fourth bracket; 242. Fourth fixed seat; 243. Second positioning plate; 2431. First arc-shaped structure; 244. Auxiliary support component; 251. Fifth bracket; 252. Fifth fixed seat; 2521. Third arc-shaped structure; 253. Third positioning plate; 2531. Second arc-shaped structure; 261. Sixth fixed seat; 262. Positioning pin; 300. Detection component; 310. First detection unit; 320. Second detection unit; 330. Positioning determination unit; 340. Drive unit; 350. Anti-collision block; 311. Connecting part; 3111. Guide part; 3112. Threaded connection part; 312. Mating part; 321. Sliding mounting base; 3211. Linear guide rail; 3212. Slider; 3213. Seventh fixed base; 322. Extended tolerance inspection sleeve; 3221. Observation slot; 3222. Positioning rod; 323. Second pad; 331, Flip plate; 3311, Manual operation terminal; 332, Card slot; 3321, Slot; 341. Clamping clamps; 342. Support frame; 400, workpiece; 410, threaded hole. Detailed Implementation

[0017] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0018] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0019] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0020] In the fields of precision machining and assembly, the geometric dimensions and tolerance control of parts are crucial. Threaded holes, as a common connection feature, directly impact the overall function and reliability of a product due to their positional accuracy and assembly performance. Design drawings often use extended tolerances to define the positional requirements of threaded holes. A common form of geometric dimension and tolerance notation is as follows: taking the threaded hole as datum C, the extended positional tolerance is, for example, marked as positional tolerance φ4mm, P80. This means that the axis of the threaded hole, within a projected length of 80mm, must deviate from the axis of the upstream datums A and B within a cylindrical tolerance zone with a diameter of 4mm. Traditional inspection methods, such as coordinate measuring machine (CMM) measurement and plug gauge inspection, suffer from a trade-off between efficiency and accuracy, are unsuitable for production line cycle control, and the fixtures cannot directly reflect the extended tolerance status. Furthermore, they cannot provide stable and accurate C-datum positioning after passing inspection, thus severely affecting the reliability of subsequent measurements dependent on the C-datum.

[0021] Please see Figures 1 to 36This invention proposes a device for detecting thread hole extension tolerance and positioning a C-datum, including a base 100 and a positioning component 200 and a detection component 300 disposed on the base 100. The positioning component 200 is used to position the A and B datums and contour of the workpiece 400 to be tested. The detection component 300 includes a first detection unit 310, a second detection unit 320, a positioning judgment unit 330, and a driving unit 340. Under simulated assembly conditions, through the cooperation of the first detection unit 310 and the second detection unit 320 and their collaborative work with the positioning judgment unit 330, it is possible to quickly determine whether the extension tolerance of the thread hole 410 of the workpiece 400 is qualified. After the qualification is qualified, the driving unit 340 applies axial force to make the first detection unit 310 and the second detection unit 320 achieve self-centering cooperation, locking the extension entity of the thread hole 410 at the theoretical C-datum position of the device. Thus, the extension tolerance judgment and C-datum establishment are completed simultaneously, significantly simplifying the detection process, reducing datum conversion, improving detection efficiency and accuracy, and enhancing the stability of C-datum positioning.

[0022] Please see Figures 1 to 6 In one embodiment of the present invention, the base 100 is used to fix other components and ensure the accuracy of their relative positions. It is a rigid plate or frame structure. The base plate 110 of the base 100 can be made of metal, for example. The upper surface of the base plate 110 is machined with precision mounting surfaces and guide rail mounting surfaces for mounting the positioning component 200 and the detection component 300, ensuring the relative position accuracy of each component. Handles 120 are provided on both sides for easy movement of the base 100. Three positioning references 130 are provided on the base 100 for positioning and installation between the base 100 and an external reference platform or inspection equipment. Pads are also provided at the four corners of the base to ensure stable installation. Several positioning holes are provided on the surface of the base 100 for installing pins for each component, accurately positioning each part and preventing positional shifts during assembly. The base 100 is also equipped with a spare test piece storage structure, such as a spare test piece mounting base 140, which has a storage hole and can hold spare test pieces 150 of different specifications vertically or at an angle, so that the operator can quickly replace the first test part 310 and avoid the test pieces being randomly placed on site, which may cause damage or misuse.

[0023] Please see Figures 1 to 22 In one embodiment of the present invention, the positioning component 200 includes a first positioning part 210, a second positioning part 220, and a contour limiting part. The positioning component 200 is fixedly mounted on the base 100 and is used to reliably position the workpiece 400 according to the designed A reference, B reference, and contour direction before inspection, so as to prevent the workpiece 400 from flipping, sliding, or rotating during the inspection process. It should be noted that the structure and position of each component of the positioning component 200 are designed according to the structure of the workpiece 400, which can realize the effective installation and precise positioning of the workpiece 400.

[0024] Please see Figures 7 to 9 In one embodiment of the present invention, the first positioning part 210 includes a first bracket 211, a first fixed base 212, a first pad 213, and an A-reference positioning ring 214. The first bracket 211 is, for example, an I-shaped bracket, which is fixed on the base 100 and cooperates with the corresponding mounting holes and positioning holes on the base 100 through connecting screws and positioning pin holes, so that its position is stable and reliable and accurate positioning is achieved. The first fixed base 212 is disposed on the bracket, and the first pad 213 and the A-reference positioning ring 214 are installed on the first fixed base 212. Specifically, a hole is opened on the first fixed base 212, through which the A-reference positioning ring 214 is positioned, and the A-reference positioning ring 214 is locked by the first pad 213 at the rear end to prevent it from falling off. The A-reference positioning ring 214 can realize the A-reference positioning of the workpiece 400, limit the X-direction of the product, and detect the A-reference end face contour deviation.

[0025] Please see Figures 10 to 14In one embodiment of the present invention, the second positioning part 220 is disposed on the base 100 and can be finely adjusted relative to the base 100. The second positioning part 220 includes a second bracket 221, a second fixed base 222, a sliding base 223, and a B-reference positioning ring 224. The second bracket 221 is fixed on the base 100 and can be fixed on the base 100 by screws and coarsely positioned by positioning holes. The second fixed base 222 is mounted on the second bracket 221 and is used to mount the sliding base 223. The sliding base 223 is slidably mounted on the second fixed base 222, for example, by a dovetail guide rail, a secondary... The guide rail or linear slider 3212 is slidably connected to the second fixed seat 222 and locked in position by a locking member; the B reference positioning ring 224 is configured to move relative to the base 100. Specifically, it is fixedly installed at the front end of the sliding seat 223, that is, the end facing the workpiece 400, and can move linearly with the sliding seat 223. The inner hole size and shape of the B reference positioning ring 224 match the theoretical size of the B reference hole or B reference cylindrical surface on the workpiece 400. It is used to position the B reference of the product, restrict the Y and Z degrees of freedom of the product, and detect the contour deviation of the B reference end face. An elastic ejector 225 is also provided inside the B-reference positioning ring 224 to apply an elastic force to the workpiece 400, causing it to conform to the first positioning part 210. The elastic ejector 225 can be, for example, a spring-loaded ejector rod 2252 structure or an elastic pin structure. One end of the ejector acts on the B-reference hole or outer circle of the workpiece 400, and the other end is opposite to the inner wall of the positioning ring or sliding seat 223. The elastic force pushes the workpiece 400 slightly towards the first positioning part 210 to eliminate the gap between the workpiece 400 and the A and B positioning determination parts 330, so that the workpiece 400 is reliably and stably clamped and positioned in both the A and B reference directions. Through the cooperation of the first positioning part 210 and the second positioning part 220, the workpiece 400 achieves complete constraint of the A and B references, avoiding detection fluctuations caused by inconsistent clamping postures of the workpiece 400.

[0026] Please see Figures 10 to 14In one embodiment of the present invention, the sliding seat 223 includes a base 2231, a push rod 2232, a cover plate 2233, a handle 2234, and a limiting pin 2235. The handle 2234 facilitates the adjustment of the push rod 2232. The push rod 2232 is mounted on the base 2231, and its front end has a T-shaped structure for mounting the B reference positioning ring 224. The push rod 2232, the base 2231, and the cover plate 2233 are respectively provided with limiting pin holes 2236 to limit the movement position of the push rod 2232 and cooperate with the limiting pin 2235 to fix the position of the push rod 2232. The sliding seat 223 can be, for example, a 60*60 sliding mechanism that can meet the movement stroke of the B reference positioning ring 224. In this embodiment, the B reference positioning ring 224 is designed with dimensions of φ71.9 and a depth of 17mm to ensure stable positioning. The B reference ring is designed with two sets of springs 2251 and push rods 2252. When the push rods 2252 and springs 2251 are subjected to force, the springs 2251 generate a reverse force, causing the push rods 2252 to press against the end face of the workpiece 400, causing it to move toward the contour end face of the A reference positioning ring 214, so that the A reference end face can be tightly attached to the end face of the A reference positioning ring 214.

[0027] Please see Figures 1 to 22 In one embodiment of the present invention, a contour limiting part is mounted on a base 100, located between a first positioning part 210 and a second positioning part 220, for limiting the contour direction of the workpiece 400. The contour limiting part includes multiple backing plates adapted to the theoretical contour of the workpiece 400, for limiting the contour direction of the workpiece 400, so that the bent portion of the workpiece 400 is within the control area, and a detection gap of predetermined width is formed between the positioning surface of each backing plate and the theoretical contour surface of the workpiece 400, and the contour tolerance is detected. Specifically, the contour limiting part includes a first contour limiting part 230, a second contour limiting part 240 and a third contour limiting part 250 arranged sequentially along the axial direction of the workpiece 400. The three work together to limit the bent portion and support the workpiece 400, and together with the first positioning part 210 and the second positioning part 220, achieve stable clamping and precise positioning of the workpiece 400.

[0028] Please see Figure 15In one embodiment of the present invention, the first contour limiting part 230 includes a third bracket 231 fixed at a specific position on the base 100, a third fixing seat 232 mounted on the third bracket 231, and a pair of parallel first positioning plates 233. The first positioning plates 233 are fixed to the designated position on the base 100 by the third bracket 231 and the third fixing seat 232. The inner working surface of the first positioning plate 233 is precisely machined according to the theoretical contour of the main bend section of the workpiece 400 to form a detection channel of constant width. When the workpiece 400 is clamped, it can be placed on the third fixing seat 232 and positioned between the first positioning plates 233. The first positioning part 210 and the second positioning part 220 work together to achieve stable clamping. The width of the detection channel is provided with a standard detection gap between it and the theoretical contour of the workpiece 400. When the main bend section of the workpiece 400 is placed in the channel, the contour tolerance can be determined by checking the clearance status with a special feeler gauge. This enables rapid and accurate control of the spatial orientation of the main body of the workpiece 400. In this embodiment, the design width between the two first positioning plates 233 is 83mm, with a 2mm detection gap on each side. Subsequently, a 2mm feeler bar can be used to check the contour surface of the plate to determine whether the contour is qualified.

[0029] Please see Figures 16 to 18 In one embodiment of the present invention, the second contour limiting part 240 includes a fourth bracket 241 fixed at a specific position on the base 100, a fourth fixing seat 242 installed on the fourth bracket 241, and a pair of parallel second positioning plates 243. Similar to the first contour limiting part 230, it restricts the direction of the bent pipe through the second positioning plates 243, so that the bent pipe part is within the control area. A first arc-shaped structure 2431 is formed on the opposite side of the two second positioning plates 243, and a detection channel of a certain width is formed between the two plates, which is adapted to the size of the workpiece 400 mounting part and leaves a detection gap. In this embodiment, the designed width between the two second positioning plates 243 is 74mm, leaving a 2mm detection gap. Subsequently, a 2mm stop bar can be used to detect the contour surface of the plate to determine whether the contour is qualified. Specifically, an auxiliary support 244 is also provided on the fourth fixed base 242. Its structure is adapted to the theoretical contour of the supported area at the bottom of the workpiece 400. For example, it can be a circular support with an S-shaped surface and can be set at the center of the fourth fixed base 242. It is understood that since the A reference positioning ring 214 and the B reference positioning ring 224 are designed in their maximum solid state, when the workpiece 400 is at its minimum size, there will be a slight up-and-down wobbling after the A reference positioning ring 214 and the B reference positioning ring 224 are installed due to the gap. By adding an auxiliary reference (i.e., auxiliary support 244) to the second contour limiting part 240, which is adapted to the bottom of the workpiece 400, the slight wobbling problem can be solved, making the product in a uniquely stable state during inspection.

[0030] Please see Figures 19 to 21In one embodiment of the present invention, the third contour limiting part 250 includes a fifth bracket 251 fixed at a specific position on the base 100, a fifth fixing seat 252 installed on the fifth bracket 251, and a pair of parallel third positioning plates 253. The direction of the bend is restricted by the two third positioning plates 253. A second arc-shaped structure 2531 is formed on the opposite side of the two third positioning plates 253, and a detection channel of a certain width is formed between the two plates, which is adapted to the size of the workpiece 400 mounting part and leaves a detection gap. In this embodiment, the design width between the two third positioning plates 253 is 74mm. The upper surface of the fifth fixing seat 252 is designed as a third arc-shaped structure 2521 with a radius of φ45 according to the roundness of the workpiece 400 to avoid interference of the hump when assembling the A reference.

[0031] Please see Figures 1 to 5 ,as well as Figure 22 In one embodiment of the present invention, the positioning component 200 further includes an assembly passability simulation detection unit 260, which includes a sixth fixing seat 261 and a positioning pin 262 disposed thereon, for simulating assembly and making anti-interference design. In this embodiment, considering that when the workpiece 400 is actually assembled, a part passes through the position of the positioning pin 262, in order to prevent interference from occurring here and causing assembly failure, two φ10 positioning pins 262 are designed to simulate the assembly parts. Subsequently, the clearance status can be detected by feeler gauge to determine whether the contour is qualified.

[0032] Please see Figures 1 to 5 as well as Figures 23 to 36In one embodiment of the present invention, a detection component 300 is disposed on a base 100 and includes a first detection unit 310, a second detection unit 320, a positioning determination unit 330, and a driving unit 340. It is used to detect the extended tolerance of the workpiece 400 and to position the C-datum of the product, and to control rotation in the Z-direction. The first detection unit 310 is detachably installed in a threaded hole 410 on the workpiece 400 and is a physical mapping of the extended tolerance entity of the threaded hole 410 being measured. Its end is provided with a first conical structure. The second detection unit 320 is adapted to the structure of the first detection unit 310 and is configured to move along a preset path. It is used to perform the functions of enveloping, guiding, detecting, and ultimately centering the C-datum of the first detection unit 310. It includes a mating cavity for accommodating the first detection unit 310 and a second conical structure that matches the first conical structure. Specifically, for example, a conical mating surface is formed at one end of the first detection unit 310, and a conical guide hole matching the conical mating surface is provided in the mating cavity of the second detection unit 320. The positioning determination unit 330 is configured to determine whether the extension tolerance of the threaded hole 410 is qualified based on whether the second detection unit 320 can complete the predetermined action when the second detection unit 320 moves to the detection position, and to perform initial positioning of the second detection unit 320 after the determination is qualified; the driving unit 340 is configured to drive the second detection unit 320 to move relative to the first detection unit 310 after the initial positioning so that the second tapered structure and the first tapered structure are in close contact and self-centering fit, thereby establishing a positioning reference based on the threaded hole 410.

[0033] Please see Figures 23 to 36In one embodiment of the present invention, the first detection part 310 is an extended tolerance detection bar, which includes a connecting part 311 that matches and connects to the threaded hole 410 to be tested, and a mating part 312 extending outward from the connecting part 311 for forming a reference. A first tapered structure is formed at the end of the mating part 312. The connecting part 311 and the mating part 312 can be a fixed structure, an integrally formed structure, or a detachable connection structure. The detachable connection structure allows for quick replacement of the front threaded connector to adapt to different specifications of threaded holes 410, thereby reducing the number of detection bars and reducing manufacturing costs. Specifically, the connecting part 311 includes a guide part 3111 and a threaded connecting part 3112. The structure of the guide part 3111 is adapted to the structure of the light hole at the front end of the threaded hole 410, and its outer diameter is smaller than the minor diameter of the thread of the threaded hole 410. It is used to insert into the light hole at the front end of the nut, serving both to detect the structure of the light hole and to provide guidance. The threaded connecting part 3112 has the same specifications as the threaded hole 410, and the first detection part 310 is connected to the workpiece 400 through the threaded connecting part 3112. It can be understood that the external thread section can be designed with various specifications such as M6, M8, and M10 depending on the different workpieces 400. The effective thread length of the connecting part 311 is sufficient to ensure that the detection rod has a stable and non-wobbling fixed state within the threaded hole 410 of the workpiece 400. In this embodiment, the guide part 3111 is designed as φ15.8xl5, which is used to insert into the φ15.9 light hole at the front end of the nut; the threaded connection part 3112 is an M20x7 thread, which is consistent with the internal thread specification of the workpiece 400, with 3-4 threads and a thread length of 5mm. It can be understood that if there are too many threads, the extension tolerance test bar will need to be screwed into the nut more times, which will take longer and the test speed will be slower. If there are too few threads, the nut will not be tightened effectively. A reasonable thread setting can improve the test efficiency while ensuring accurate test and stable reference positioning.

[0034] Please see Figures 26 to 28In one embodiment of the present invention, the mating part 312 is generally a cylindrical rod. A first conical structure is machined at the end of the cylindrical rod away from the workpiece 400. This first conical structure is a conical mating surface used to form a reference. Its cone angle can be selected according to the self-centering effect and contact area requirements. The middle of the rod is a handle portion, on which the specifications of the extension tolerance test bar can be engraved. It should be noted that the length design of the cylindrical portion of the first test part 310 matches the extension tolerance requirements in the workpiece 400 drawing. In this embodiment, the extension position of the threaded hole 410 being tested is marked as φ4mm, P80. The specifications of the first test part 310 are φ31xL80. The effective length extending outward from the reference surface of the workpiece 400 is designed according to the length P80, so that its axis represents the spatial position of the threaded hole 410 extension entity within this length range. Therefore, during the testing process, the mating of the first test part 310 and the second test part 320 can realistically simulate the assembly state of the threaded hole 410 extension tolerance. The maximum outer diameter of the first detection part 310 is φ31. The outer diameter of the end of the mating part 312 that connects to the connecting part 311 is designed to be φ31. The radial dimension of the handle part in the middle can be smaller than the maximum outer diameter, for example, it can be designed to be φ16 to simplify the overall structure. The end of the mating part 312 away from the connecting part 311 is designed to be φ14xL13. The end can be opened with a cross groove that is 3mm wide and 5mm deep, so that the extended tolerance test bar can be screwed into the nut hole using tools such as a Phillips pneumatic screwdriver. The end is also provided with a first tapered structure, specifically, a 92° tapered surface is machined on the end face and an R angle is made. It can be adapted to the tapered hole structure on the second detection part 320, so that the test bar can be automatically guided and centered when in contact. The outer diameter of the handle part near the mating part 312 is φ31, which facilitates assembly and observation.

[0035] Please see Figures 23 to 36In one embodiment of the present invention, the second detection unit 320 includes a sliding mounting base 321 and an extended tolerance detection sleeve 322. The sliding mounting base 321 is disposed on the base 100. The extended tolerance detection sleeve 322 is connected to the sliding mounting base 321 and connected to the base 100 via the sliding mounting base 321, and can move linearly along a preset path on the base 100. Specifically, the sliding mounting base 321 includes a linear guide rail 3211 fixed to the base 100 and a seventh fixed base 3213 slidably connected to the linear guide rail 3211 via a bottom slider 3212. The extended tolerance detection sleeve 322 is fixed to the end of the seventh fixed base 3213 facing the workpiece 400, and its rear end is locked and fixed by a second pad 323. It can reciprocate linearly along the preset path on the linear guide rail 3211 with the seventh fixed base 3213. A guide rail mounting surface is provided on the base 100 along the detection direction (i.e., the preset path direction) for mounting a linear guide rail 3211. The track of the linear guide rail 3211 can be fixed to the prefabricated guide rail mounting surface of the base 100 by screws and positioning pins 262. The axis of the guide rail serves as the theoretical straight-line trajectory of the movement of the second detection unit 320. This straight-line trajectory is precisely assembled, adjusted, and calibrated in one go relative to the positioning component 200 and the positioning determination unit 330 and drive unit 340 of the detection component 300 on the base 100, so that the theoretical C reference axis of this device is clearly defined in structure and coincides with the actual movement direction of the detected part.

[0036] Please see Figures 29 to 30In one embodiment of the present invention, the interior of the extension tolerance detection sleeve 322 is provided with a mating cavity along the axial direction. The rear section of the mating cavity is a second conical structure, namely a conical guide hole, which matches the first conical structure of the first detection part 310. It is used to perform a self-centering engagement with the first conical structure when the subsequent driving part 340 applies force. The front section of the mating cavity is a cylindrical hole, which is used to provide rough guidance and limit the cylindrical rod of the extension tolerance detection bar during the forward movement of the extension tolerance detection sleeve 322, so as to prevent the first detection part 310 from generating excessive sway before the conical surface is fully in contact. When designing the mating cavity, the radial clearance between the cylindrical section of the mating cavity of the extension tolerance detection sleeve 322 and the cylindrical section of the mating part 312 is precisely controlled within the radius range corresponding to the measured extension position, so that when the second detection part 320 reaches the preset position, its radial offset can truly reflect the extension tolerance state of the threaded hole 410, providing a geometric basis for subsequent judgment. In this embodiment, the extension tolerance of the threaded hole 410 is marked as positional tolerance φ4mm, P80. The specification dimensions of the extension tolerance detection sleeve 322 are φ45xL110, and the inner diameter of one end is designed to be φ35xL67, with a gap of 4mm corresponding to the corresponding dimension φ31xL80 of the extension tolerance detection rod. The middle part of the extension tolerance detection sleeve 322 has a radially opened observation groove 3221 with a length of 56x27.5. The other end is designed as a cylinder with a depth of φ17xL7.14 on the side near the observation groove 3221, serving as a guide section. The side away from the observation groove 3221 has a tapered guide hole with a depth of 5.86x12°, i.e., a second tapered structure, for positioning the C datum. The overall structure of this side end is designed as a positioning rod 3222 with a depth of φ30x33, for assembly with the φ20 hole of the seventh fixing seat 3213. The end face of the positioning rod 3222 has an M6 threaded hole 410 for locking the second pad 323.

[0037] Please see Figures 23 to 36In one embodiment of the present invention, the extension tolerance of the threaded hole 410 of the nut on the workpiece 400 is marked as position tolerance φ4mm, P80. After the extension tolerance test bar is assembled with the threaded hole 410, the extension tolerance test sleeve 322 moves forward along the linear guide 3211, so that the extension tolerance test bar can be smoothly inserted into the extension tolerance test sleeve 322. After the extension tolerance test bar is inserted into the extension tolerance test sleeve 322, it continues to move axially until it reaches a preset position, that is, when the distance between the end faces of the extension tolerance test bar and the extension tolerance test sleeve 322 is about 5.5mm, it means that the position tolerance of the extension tolerance length P80 is qualified at 4mm. At this time, it can be determined that the extension tolerance P80 is qualified. Set the tolerance to 4mm for compliance; the extended tolerance inspection sleeve 322 continues to move forward until the 92° taper rounded corner of the front end of the φ14xL13 extended tolerance inspection rod is in close contact with the 12° taper of one end of the φ17 guide section of the extended tolerance inspection sleeve 322. Since the extended tolerance inspection sleeve 322 is limited in both vertical and horizontal directions, it can only move back and forth along the guide rail. Therefore, at this time, the tapered shape of the extended tolerance inspection sleeve 322 after being limited automatically corrects the radial swing of the front end of the extended tolerance inspection rod. Since the corrected extended tolerance inspection rod is connected to the nut, it restricts the C datum of the product and controls the Z-axis rotation. At this time, the C datum positioning of the product is effectively established, and subsequent inspections can be carried out under this datum.

[0038] Please see Figures 23 to 36In one embodiment of the present invention, the positioning determination unit 330 includes a flap 331 disposed on the second detection unit 320 and a retainer 332 disposed on the base 100. The flap 331 is rotatably connected to the second detection unit 320, for example, by means of a pin hinged to the side wall of the seventh fixed seat 3213. Its free end faces the retainer 332 on the base 100. The retainer 332 is a T-shaped seat, which is fixedly installed on the base 100 and has a groove 3321 inside. When the second detection unit 320 moves to the detection position, if the extension tolerance is qualified, the positioning determination unit 330 can complete the predetermined action, that is, it can flip the flap 331 into the groove 3321 of the T-shaped seat, and at this time, the initial positioning can be achieved by the engagement of the flap 331 and the T-shaped seat. It is understandable that when the second detection unit 320 moves along the preset path, if the extension tolerance detection bar and the extension tolerance detection sleeve 322 can be assembled and the positioning judgment unit 330 can complete the predetermined action at the preset position, it means that the extension tolerance is qualified in both the radial and axial dimensions. If the extension tolerance of the threaded hole 410 is not qualified, the extension tolerance detection bar and the extension tolerance detection sleeve 322 cannot be assembled, or the flap 331 will be blocked by the side wall of the groove 3321 and cannot be inserted into the groove 3321. This structure can intuitively indicate whether the extension tolerance of the threaded hole 410 is qualified. It should be noted that there is an movable gap between the flip plate 331 and the groove wall of the card seat 332. That is, there is a preset gap between the groove width of the T-shaped seat and the thickness of the flip plate 331. This preset gap is designed to take into account the manufacturing tolerance of the nut end face during actual production. In this embodiment, the redundant gap between the flip plate 331 and the groove 3321 of the T-shaped seat is a tolerance value of 3mm. The gap design allows the flip plate 331 and the groove 3321 of the T-shaped seat to form a movable space, thereby enabling the solid of the conical tail end of the extended tolerance detection bar to effectively fit with the conical shape in the middle of the extended tolerance detection sleeve 322.

[0039] Please see Figures 23 to 36 In one embodiment of the present invention, the flap 331 is designed as a rod with a manual operation end 3311. When the second detection unit 320 reaches the preset position, the operator can gently push the flap 331 to attempt to insert it into the slot 3321. If the flap 331 is inserted into the slot without obstruction and into place, it indicates that the radial offset of the threaded hole 410 extension body in that axial position does not exceed the boundary corresponding to the tolerance zone diameter, and the extension tolerance is qualified. Conversely, if the flap 331 cannot be inserted into the slot 3321 of the T-seat, it indicates that the axial position does not meet the extension tolerance requirements, and the extension tolerance of the threaded hole 410 is determined to be unqualified. The judgment can be achieved based on mechanical fit and preset clearance, without the need for a complex electronic measurement system, making the operation simple and accurate.

[0040] Please see Figures 23 to 36In one embodiment of the present invention, the detection component 300 further includes an anti-collision block 350, which is fixed on the base 100 and used to limit the maximum stroke of the extension tolerance detection sleeve 322. The anti-collision block 350 cooperates with the end face of the sliding mounting seat 321 and is disposed at both ends of the linear guide rail 3211. During the movement of the second detection part 320 toward the workpiece 400, when the end face of the sliding mounting seat 321 contacts the anti-collision block 350, it indicates that the second detection part 320 has reached the maximum stroke position. At this time, if the flap 331 can be smoothly inserted into the groove 3321 of the T-shaped seat, the extension tolerance position is judged to be qualified; otherwise, it is judged to be unqualified. It can be understood that the device is designed to set the anti-collision block 350 at a precise axial position according to the requirements of the extension tolerance position, to assist in the judgment of the extension tolerance position. If the extension tolerance is unqualified, the flap 331 cannot be engaged when the sliding mounting seat 321 reaches the position of the anti-collision block 350.

[0041] Please see Figures 23 to 36In one embodiment of the present invention, the drive unit 340 includes a clamp 341, which is used to press the extension tolerance detection sleeve 322 and make it continue to move forward after the second detection unit 320 completes the initial positioning. The clamp 341 can be a pneumatic clamp, a hydraulic clamp, or a lever-type mechanical clamp, etc. It is mounted on the support frame 342 and fixed to the base 100 through the support frame 342. One clamping end of the clamp 341 faces the second detection unit 320 and the end away from the first detection unit 310. By adjusting the position and stroke of the clamp 341, after the flip plate 331 and the T-shaped seat confirm that the extension tolerance is qualified, the movable jaw of the clamp 341 can press the second pad 323 through the stroke action. Specifically, for example, the support frame 342 is located on the side of the linear guide rail and near the maximum stroke position of the second detection unit 320. The clamp 341 is rotatably connected to the support frame 342. After initial positioning, rotating the clamp head of the clamp 341 along the clamp 341 axis will press the pressure point onto the second pad 323. By applying force through the clamp 341, the second detection unit 320 will be forced to move forward. Since there is a certain gap between the flap 331 and the groove 3321 of the T-shaped seat, the second detection unit 320 can continue to move forward along the guide rail after being subjected to force, thereby extending the tolerance detection sleeve 322 to continue to move a certain stroke towards the first detection unit 310. During this stroke, the second conical structure in the cavity of the second detection unit 320 gradually makes full contact with the first conical structure of the first detection unit 310. Under the continuous axial force applied by the clamp 341, sufficient contact pressure is generated between the conical surfaces. With the help of the self-centering characteristic of the conical surfaces, the small radial deviation and gap between the first detection unit 310 and the second detection unit 320 are eliminated, so that the axis of the first detection unit 310 is locked on the theoretical C reference axis, and the C reference is established. Since the conical surface has a large contact area and good repeatability, it can provide a highly consistent C reference position, which is beneficial to all subsequent dimension and form and position detections with the C reference as a reference.

[0042] Please see Figures 1 to 37 The present invention also proposes a method for detecting thread hole extension tolerance and positioning C-datum, comprising: S100: Install the first detection unit 310 into the threaded hole 410 on the workpiece 400; S200, The positioning component 200 positions the workpiece 400 to be measured; S300, the second detection unit 320 is moved along the preset path. If the first detection unit 310 can be assembled with the second detection unit 320 and the positioning determination unit 330 can complete the predetermined action, then the extension tolerance of the threaded hole 410 is determined to be qualified. S400. After passing the test, the second detection unit 320 is initially positioned by the positioning component, and the second detection unit 320 is further pushed by the drive unit 340 so that the second conical structure of the second detection unit 320 is in close contact with the first conical structure of the first detection unit 310 and self-centering fits, thereby establishing the C reference. S500, based on the established C datum, the form and position tolerances of workpiece 400 are inspected.

[0043] Please see Figures 1 to 37 In one embodiment of the present invention, in step S100, before the detection begins, the device is first checked to see if each component and part is qualified and complete; then, a pneumatic Phillips screwdriver is aligned with the Phillips groove at the end of the extension tolerance test bar, and the M20 screw at the front end of the extension tolerance test bar is aligned with the M20 nut of the workpiece 400. The pneumatic screwdriver is then activated to quickly screw the extension tolerance test bar into the nut. The axis of the extension tolerance test bar is the extension axis of the threaded hole 410 to be tested, which prepares for subsequent detection and positioning.

[0044] Please see Figures 1 to 37 In one embodiment of the present invention, in step S200, before the workpiece 400 is positioned, the position status of each component is checked, the second detection part 320 is slid along the linear guide rail 3211 to the end, and the second positioning part 220 is pulled outward to make room for placing the workpiece 400. After preparation, the workpiece 400 with the extended tolerance inspection bar installed is placed into the inspection channel formed by the components of the positioning assembly 200. The hump end of the workpiece 400 is aligned with the spherical surface of the A reference positioning ring 214 and inserted into the A reference positioning ring 214. Then, the second positioning part 220 is pushed towards one side of the workpiece 400 so that the B reference positioning ring 224 at the front end can be smoothly fitted into the φ70 diameter end of the workpiece 400. After pushing the sliding seat 223 to the target position, the positioning is achieved by engaging the limiting pin 2235. At this time, the elastic ejector 225 in the B reference positioning ring 224 acts forward in the X direction, so that the workpiece 400 is tightly attached to the A reference spherical surface. Each contour limiting part can achieve contour limiting and auxiliary support for the workpiece 400. At this time, the A and B references are reliably established.

[0045] Please see Figures 1 to 37In one embodiment of the present invention, in step S300, the extension tolerance detection sleeve 322 is pushed to move along a preset path on the linear guide rail 3211 so that the mating cavity of the second detection part 320 accommodates the first detection part 310, so that the extension tolerance detection sleeve 322 can be smoothly fitted into the extension tolerance detection bar on the workpiece 400. When it moves to the detection position, the extension tolerance detection bar has been inserted into the extension tolerance detection sleeve 322. The flip plate 331 is flipped so that it can be smoothly inserted into the groove 3321 of the T-shaped seat. At this time, the extension tolerance position is determined to be φ4, and the P80 test is qualified. If the extension tolerance detection bar cannot be smoothly inserted into the extension tolerance detection sleeve 322, or the flip plate 331 cannot be smoothly inserted into the groove 3321 of the T-shaped seat, the extension tolerance position is determined to be φ4mm, and the P80 test is unqualified. During the movement of the extended tolerance inspection sleeve 322, the anti-collision block 350 limits its stroke to prevent the extended tolerance inspection sleeve 322 from colliding with the workpiece 400 and other components. When the second inspection unit 320 moves to the maximum stroke position (i.e., the sliding mounting seat 321 contacts the anti-collision block 350), if the flip plate 331 can be smoothly inserted into the groove 3321 of the T-shaped seat, the extended tolerance position is determined to be φ4mm, and the P80 inspection is qualified; otherwise, it is unqualified.

[0046] Please see Figures 1 to 37 In one embodiment of the present invention, in step S400, after the qualification is determined, the flap 331 is inserted into the groove 3321 of the T-shaped seat to achieve initial positioning of the second detection part 320. Since the flap 331 and the groove 3321 of the T-shaped seat have a clearance tolerance value during design, the flap 331 and the T-shaped seat form a movable space. At this time, the pressure head of the clamp 341 is rotated along the axis of the clamp 341 so that the pressure point presses onto the second pad 323 at the tail end and clamps the clamp 341. The clamp 341 applies an axial thrust to make the extension tolerance detection sleeve 322 move forward with the whole, so that its internal conical guide hole can effectively fit the conical mating surface of the extension tolerance detection rod. Since the mating parts of the extension tolerance detection rod and the extension tolerance detection sleeve 322 are both conical, the two conical surfaces eliminate all small radial deviations through mutual sliding action, realizing The fully coincident self-centering state ensures that the extended tolerance inspection bar is effectively centered after positioning, meaning that the axis of the extended tolerance inspection bar is completely coincident with the theoretical C-datum axis of the device. Since the extended tolerance inspection bar is connected to the threaded hole 410 of the workpiece 400, the axis of the threaded hole 410 is also precisely positioned, thus completing the C-datum positioning. By maintaining this force state or mechanically locking the relative position after the conical surface reaches stable contact, a stable and accurate C-datum can be successfully established within this device, realizing an integrated process from extended tolerance inspection to C-datum establishment. Subsequently, according to actual inspection needs, other dimensional and geometric tolerance measurements can be performed using this C-datum as a reference by clamping fixtures or by setting the entire device in upstream / downstream inspection equipment, ensuring the accuracy and reliability of product inspection.

[0047] Please see Figures 1 to 37 In one embodiment of the present invention, after completing the C-datum positioning in step S500, the form and position tolerances of the workpiece 400 can be detected. In this embodiment, the detection of the contour tolerance of the workpiece 400 can be achieved by combining the positioning component 200. Specifically, this includes using a 2mm feeler bar to detect the gap between the two end faces and the reference surface of the device; if it stops, the contour is qualified; using a 2mm feeler bar to detect the gap between the profile surface of the first contour limiting part 230 and the reference surface of the gauge; if it stops, the contour is qualified; using a 1mm feeler gauge to detect the gap between the cylinder of the 2-φ10 positioning pin 262 and the reference surface of the device; if it passes, it is qualified; visually inspecting the second contour limiting part 240, the third contour limiting part 250 of the product and each detection block of the device; if there is no interference, it is qualified, etc. If all parts pass the inspection, the product is qualified, and the inspection is completed.

[0048] In summary, the thread hole extension tolerance detection and C-datum positioning device and method of the present invention, through the cooperation of the extension tolerance detection bar and the extension tolerance detection sleeve 322, and the engaging design of the flip plate 331 and the card holder 332, can synergistically achieve rapid and accurate determination of the radial and axial position extension tolerance of the thread hole 410 of the product. Combined with the drive unit 340, it can achieve precise and stable C-datum positioning, thereby comprehensively and efficiently verifying other key dimensions, contours and assembly compatibility of the product, significantly improving the efficiency and accuracy of product quality control.

[0049] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

[0050] Throughout this description, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of the invention. However, those skilled in the art will recognize that embodiments of the invention may be practiced without one or more of these specific details or by other devices, systems, components, methods, parts, materials, components, etc. In other instances, well-known structures, materials, or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

[0051] Throughout this specification, the terms "an embodiment," "embodiment," or "specific embodiment" refer to a particular feature, structure, or characteristic described in connection with an embodiment that is included in at least one embodiment of the invention, but not necessarily in all embodiments. Therefore, the various representations of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic of any specific embodiment of the invention can be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the invention described and illustrated herein may be based on the teachings herein and will be considered part of the spirit and scope of the invention.

[0052] It should also be understood that one or more of the elements shown in the figures may be implemented in a more separate or more integrated manner, or may even be removed because they are inoperable in certain circumstances or provided because they may be useful for a particular application.

[0053] Furthermore, unless otherwise expressly stated, any arrows in the accompanying drawings should be considered illustrative only and not limiting. Additionally, unless otherwise stated, the term "or" as used herein is generally intended to mean "and / or". Where a term is anticipated to provide a separation or combination capability that is unclear, a combination of components or steps will also be considered as indicated.

[0054] As used herein and throughout the claims below, unless otherwise specified, “a” and “the” include the plural references. Similarly, as used herein and throughout the claims below, unless otherwise specified, “in” means “in” and “on”.

[0055] The above description of the embodiments shown in this invention (including the content set forth in the abstract of the specification) is not intended to be an exhaustive enumeration or to limit the invention to the precise forms disclosed herein. Although specific embodiments and examples of the invention have been described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the invention, as will be recognized and understood by those skilled in the art. As indicated, these modifications can be made to the invention in accordance with the above description of the embodiments described herein, and such modifications will be within the spirit and scope of the invention.

[0056] This document has generally described the systems and methods in detail to aid in understanding the invention. Furthermore, various specific details have been set forth to provide a general understanding of embodiments of the invention. However, those skilled in the art will recognize that embodiments of the invention can be practiced without one or more specific details, or using other means, systems, accessories, methods, components, materials, parts, etc. In other instances, well-known structures, materials, and / or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

[0057] Therefore, although the invention has been described herein with reference to specific embodiments thereof, freedom of modification, various changes and substitutions are also within the scope of the foregoing disclosure, and it should be understood that in some cases, certain features of the invention may be adopted without departing from the scope and spirit of the invention and without corresponding use of other features. Thus, many modifications can be made to adapt a particular environment or material to the essential scope and spirit of the invention. The invention is not intended to be limited to the specific terminology used in the following claims and / or the specific embodiments disclosed as the best mode for carrying out the invention, but the invention will include any and all embodiments and equivalents falling within the scope of the appended claims. Therefore, the scope of the invention will be defined only by the appended claims.

Claims

1. A threaded hole extension tolerance detection and C-reference positioning device, characterized by, The application relates to a positioning and detection device for a threaded hole of a workpiece, which comprises a base, a positioning assembly arranged on the base and used for positioning the workpiece, and a detection assembly arranged on the base. The positioning assembly comprises a first positioning part which comprises an A-reference positioning ring used for positioning an A-reference of the workpiece, and a second positioning part which comprises a B-reference positioning ring capable of moving relative to the base, and the B-reference positioning ring is provided with an elastic ejector used for applying an elastic force to the workpiece so that the workpiece is attached to the first positioning part. The positioning assembly further comprises a contour limiting part which is fixedly arranged on the base and comprises a plurality of abutting plates, and a positioning surface of each abutting plate and a theoretical contour surface of the workpiece form a detection gap with a predetermined width. The first detection part comprises a connecting part which is threadedly connected with the threaded hole, and a matching part used for forming a reference, and the first taper structure is formed at the end of the matching part. The connecting part comprises a guide part which is matched with a light hole structure at the front end of the threaded hole and has an outer diameter smaller than a minor diameter of the threaded hole, and a threaded connecting part which is consistent with the size of the threaded hole and is used for connecting the first detection part with the workpiece. The second detection part comprises a sliding mounting base arranged on the base, and an extension tolerance detection sleeve connected with the sliding mounting base and capable of moving linearly along the preset path on the base. The positioning and judging part comprises a clamping base arranged on the base, and a turning plate which is rotatably connected with the second detection part. The preset action is that the turning plate is clamped into a groove of the clamping base, and an active gap is arranged between the turning plate and a groove wall of the clamping base.

2. The threaded hole extension tolerance detection and C-reference positioning device of claim 1, wherein, The driving part comprises a pressing clamp used for pressing the extension tolerance detection sleeve and making the extension tolerance detection sleeve continuously move forward after the second detection part completes the primary positioning. The detection assembly further comprises an anti-collision block which is fixed on the base and used for limiting the maximum stroke of the extension tolerance detection sleeve. The application further relates to a method for positioning and detecting a threaded hole of a workpiece, which comprises the following steps:

3. The threaded hole extension tolerance detection and C-reference positioning device of claim 1, wherein, ​ 4. The threaded hole extension tolerance detection and C-reference positioning device of claim 1, wherein, ​ 5. The threaded hole extension tolerance detection and C-reference positioning device of claim 4, wherein, ​ ​ ​ 6. The threaded hole extension tolerance detection and C-reference positioning device of claim 1, wherein, ​ ​ ​ 7. The threaded hole extension tolerance detection and C-reference positioning device of claim 1, wherein, ​ ​ ​ ​ 8. The threaded hole extension tolerance detection and C-reference positioning device of claim 6, wherein, ​ 9. The threaded hole extension tolerance detection and C-reference positioning device of claim 6, wherein, ​ 10. A method of threaded hole extension tolerance detection and C-reference positioning, comprising: ​ ​ Positioning the workpiece by the positioning assembly; Moving the second detection part along a preset path, and if the first detection part can be assembled with the second detection part and the positioning determination part can complete a predetermined action, it is determined that the extension tolerance of the threaded hole is qualified; After the determination is qualified, the second detection part is initially positioned by the positioning member, and the second detection part is further pushed by the driving part, so that the second conical structure of the second detection part is in close contact with the first conical structure of the first detection part and is self-centered, thereby establishing a C reference; Based on the established C reference, the shape and position tolerance of the workpiece is detected.

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