A cylindrical workpiece outer diameter tolerance and roundness detection device and a detection method thereof

Abstract

The present application relates to the technical field of workpiece detection, and especially relates to a cylindrical workpiece outer diameter tolerance and roundness detection device, which comprises a feeding force measuring unit, a lifting adjusting unit and a rotating positioning unit arranged on a rack; the feeding force measuring unit comprises a fixed plate, a pushing driving part, a pressure sensor, a positioning plate and a plug gauge; the pushing driving part is fixedly connected with the fixed plate; the output end of the pushing driving part is drivingly connected with the pressure sensor; the pressure sensor is fixedly connected with the positioning plate; and the plug gauge is elastically connected with the positioning plate; the output end of the lifting adjusting unit is fixedly connected with the fixed plate; the feeding force measuring unit, the lifting adjusting unit and the rotating positioning unit are organically integrated on the same rack, so that the integrated online detection of the outer diameter tolerance and the roundness is realized; the workpiece only needs to be clamped once to complete two detection tasks, and the detection efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of workpiece inspection technology, and in particular to a device for detecting the outer diameter tolerance and roundness of cylindrical workpieces. Background Technology

[0002] In the field of mechanical manufacturing, the outer diameter accuracy and roundness of cylindrical parts are key geometric parameters affecting product assembly quality, motion performance, and service life. With the rapid development of manufacturing towards automation and intelligence, increasingly higher demands are being placed on the inspection efficiency, measurement accuracy, and automation integration capabilities of online inspection equipment.

[0003] Currently, the measurement of the outer diameter and roundness of cylindrical workpieces mainly involves the following methods: Traditional manual measurement methods, using general measuring tools such as vernier calipers and outside micrometers for contact measurement, or using V-blocks in conjunction with dial indicators to measure roundness. Roundness measuring instruments use a precision spindle to rotate a displacement sensor around the measured cross-section, accurately recording radius changes with an accuracy of up to 0.025μm. Coordinate measuring machines (CMMs) collect the coordinates of multiple points on the circumference of the workpiece, fit them into a circle using software, and calculate roundness; this method offers extremely high accuracy but is expensive, slow, and requires harsh environmental conditions, making it unsuitable for rapid online inspection. Other automated measuring devices, some patents and products already utilize measuring columns, caliper heads, and adjusters to achieve automated outer diameter inspection.

[0004] Most existing devices can only perform outer diameter measurement or roundness measurement independently, making it difficult to efficiently integrate the two detection functions in the same device. This results in workpieces needing to be transferred between multiple devices, reducing detection efficiency and increasing equipment investment costs.

[0005] In contact measurement, the lack of precise control and buffering protection of contact force can easily scratch the surface of the machined workpiece, and rigid impacts may damage high-precision sensors. Existing fixed-feed measurement schemes lack effective elastic conversion structures, making it difficult to accurately convert dimensional deviations into measurable physical quantities under fixed cylinder feed conditions, thus limiting the resolution and accuracy of online detection. Summary of the Invention

[0006] The technical problem to be solved by the present invention is: in order to overcome the lack of precise control and buffer protection of contact force in the existing contact measurement technology, which on the one hand easily scratches the surface of the processed workpiece, and on the other hand, rigid impact may damage the high-precision sensor, a cylindrical workpiece outer diameter tolerance and roundness detection device is provided.

[0007] The technical solution adopted by the present invention to solve its technical problem is: a cylindrical workpiece outer diameter tolerance and roundness detection device, including a feed force measuring unit, a lifting adjustment unit and a rotation positioning unit arranged on the frame; The feed force measuring unit includes a fixed plate, a push drive, a pressure sensor, a positioning plate, and a plug gauge. The push drive and the fixed plate are fixedly connected. The output end of the push drive is connected to the pressure sensor. The pressure sensor and the positioning plate are fixedly connected. The plug gauge and the positioning plate are elastically connected. The push drive is used to provide power for the plug gauge to move away from or towards the position. The output end of the lifting adjustment unit is fixedly connected to the fixed plate. The lifting adjustment unit is used to provide power for the height adjustment of the feed force measuring unit. The rotary positioning unit is used to place the workpiece and provide power for its rotation. By organically integrating the feed force measuring unit, lifting adjustment unit and rotary positioning unit on the same frame, integrated online inspection of outer diameter tolerance and roundness is realized. The workpiece only needs to be clamped once to complete two inspection tasks, which improves inspection efficiency. The coordinated work of each functional unit provides the hardware foundation for fully automated online inspection. By setting an elastic element or elastic hinge structure between the plug gauge and the pressure sensor, the contact force between the plug gauge and the workpiece surface can be precisely controlled and flexibly buffered, fundamentally avoiding the workpiece surface scratch problem commonly found in traditional rigid contact measurements. It is particularly suitable for online inspection of machined or ultra-machined surfaces.

[0008] To address the issue of the lack of a stable positioning structure for the pressure sensor during connection and installation between the pneumatic slide and the positioning plate, which leads to sensor positional shift or uneven force distribution and affects detection accuracy and repeatability, a feed force measuring unit is further included, comprising a connecting plate. The connecting plate has a first groove for placing the pressure sensor, which is fitted into the first groove. The connecting plate is arranged between the push drive component and the pressure sensor.

[0009] To address the issue of insufficient precise positioning constraints in the connection between the pressure sensor and the positioning plate, which can easily cause the relative position of the sensor output end and the positioning plate to shift, affecting the efficiency of value transmission and measurement reliability, the system further includes a mounting portion protruding from the positioning plate, with a second groove provided on the mounting portion for placing the pressure sensor, and the pressure sensor being arranged in the second groove.

[0010] To address the lack of an elastic buffer structure between the plug gauge and the positioning plate, which easily generates rigid impacts when in contact with the workpiece, potentially scratching the surface of the machined workpiece and damaging the high-precision pressure sensor due to the impact load, and the inability to convert dimensional deviations into force changes, a further solution is provided: the positioning plate has an installation groove in which the plug gauge slides. An elastic element is arranged inside the mounting slot. One end of the elastic element abuts against the positioning plate, and the other end abuts against the plug gauge.

[0011] To address the issues of unreliable guidance and limiting constraints when plug gauges slide within the mounting groove, potentially leading to misalignment, jamming, or dislodgement, as well as inconvenient assembly and disassembly that affect measurement stability and maintenance efficiency, a further solution is proposed: a feed force measuring unit comprising a pressure plate and locating pins. The pressure plate and the positioning plate are fixedly connected on their top surfaces, and the mounting groove is located on the top surface of the positioning plate. The plug gauge has a movable hole, which is an oblong hole extending along the direction of the mounting groove. The positioning pin passes through the pressure plate and extends into the movable hole.

[0012] To address the issues of unstable contact and drifting of the contact point position due to changes in workpiece diameter when the end of the plug gauge contacts the outer cylindrical surface of the workpiece using a flat or other non-circular shape, thus affecting measurement repeatability and accuracy, a further improvement is made to include an arc-shaped contact portion on the end of the plug gauge closest to the workpiece.

[0013] To address the issue that the feed force measuring unit lacks high-precision linear guidance support during horizontal forward and backward movement, causing the moving parts to wobble or jam, thus affecting the repeatability of the plug gauge and the directionality of force transmission, the feed force measuring unit further includes a first slider and a first slide rail that matches the first slider. The first slider and the positioning plate are fixedly connected, the first slide rail and the fixed plate are fixedly connected, and the first slider and the first slide rail are slidably connected.

[0014] To address the lack of a simple and reliable adjustment mechanism for the overall lifting of the feed force measuring unit, which makes it unable to adapt to the measurement requirements of workpieces of different lengths and makes it difficult to achieve accurate height changes and positioning during multi-section measurements, a lifting adjustment unit is further included, comprising an adjustment screw, a base plate, a lifting plate, a second slider, and a second slide rail. The second slide rail is fixedly connected to the frame, the second slider is slidably connected to the second slide rail, and the second slider is fixedly connected to the lifting plate. The substrate and the frame are fixedly connected; The adjusting screw is rotatably connected to the base plate, and the adjusting screw is threadedly connected to the lifting plate.

[0015] To address the issues of bulky structure, numerous leakage points, insufficient rotational accuracy, and poor axial positioning reliability of workpieces caused by the separate design of rotary fixtures and vacuum adsorption structures or the need for external rotary joints, a rotary positioning unit is further included, comprising a rotary drive component, a rotary fixture, and a transmission assembly. The transmission assembly includes bearing housings, couplings, rotating bearings, sealing rings, and fixing components; the bearing housings and the frame are fixedly connected. The bottom of the rotating jig has a protruding connecting part. The connecting part passes through the bearing seat and is connected to the rotating drive component through a coupling. The rotating drive component is fixedly connected to the frame and is used to provide power for the rotation of the rotating jig. The fastener and the connecting part are threaded together, and the fastener is located below the bearing housing; The bearing housing has a sealed cavity surrounding the connecting part, and the bearing housing has an air inlet that communicates with the sealed cavity. The rotating bearing is located at the end of the bearing housing and is sleeved on the connecting part; The sealing ring is fitted onto the connecting part, and the sealing ring is located between the rotating bearing and the sealing cavity on its side. The sealing ring is used to seal the gap where the connecting part passes through the sealing cavity. The rotating jig and the frame are rotatably connected. The top surface of the rotating jig has a positioning cavity for placing the workpiece. The connecting part has a main air passage that communicates with the sealed cavity. The rotating jig has suction holes, some of which are located on the top surface of the rotating jig. Suction cups are arranged in the suction holes on the top surface of the rotating jig. Some of the suction holes are located at the bottom of the positioning cavity. The suction holes are connected to the main air passage.

[0016] A method for detecting the outer diameter tolerance and roundness of a cylindrical workpiece using a measuring device includes the following steps: S1 Limit Calibration Steps: Adjust the plug gauge to the target measurement section height of the standard cylindrical workpiece using the lifting adjustment unit. Place the standard cylindrical workpiece on the rotary positioning unit for adsorption and fixation. Push the drive component to drive the plug gauge to contact the outer surface of the standard cylindrical workpiece. Adjust the position of the mechanical limit structure set on the drive component so that the pressure sensor reading is within the preset target force value range. Record the current stable reading of the pressure sensor as the reference force value F0 and record the current limit position as the reference position. Based on the reference position, the mechanical limit structure is adjusted to two different positions, and the stable readings of the pressure sensor and the corresponding stroke change Δx are recorded at each position. The force-displacement relationship coefficient k = ΔF / Δx is calculated based on the force change ΔF and the stroke change Δx. S2 Assembly and Safety Inspection Steps: Remove the standard cylindrical workpiece, place the cylindrical workpiece to be tested on the rotary positioning unit, and center the workpiece so that the boss at the bottom of the workpiece is embedded in the positioning cavity of the rotary positioning unit. Start vacuum adsorption to fix the workpiece to be tested. Monitor the adsorption vacuum degree through the negative pressure detection sensor. If it is lower than the set threshold, the rotary drive is prohibited from starting, and the drive is also prohibited from being pushed forward. S3 Measurement Steps: Adjust the plug gauge to the same height as in S1 using the lifting adjustment unit. After the adsorption vacuum degree meets the set requirements, push the drive component to feed to the limit position with the reference position as the target. The plug gauge contacts the outer surface of the cylindrical workpiece to be measured, and the pressure sensor outputs a stable force value F. x ; S4 outer diameter tolerance judgment steps: Based on the force-displacement relationship coefficient k obtained from calibration, calculate the outer diameter deviation value ΔD of the workpiece at this section = (Fx -F0) / k, the measured outer diameter value D=D0+ΔD, where D0 is the nominal outer diameter value of the standard cylindrical workpiece, the measured outer diameter value D is compared with the nominal outer diameter value D0 of the standard cylindrical workpiece and the preset tolerance range. If D0-T≤D≤D0+T, the outer diameter of this section is determined to be qualified; if D>D0+T, the outer diameter is determined to be too large; if D<D0-T, the outer diameter is determined to be too small; S5 roundness determination step: driving the rotary positioning unit to drive the workpiece to rotate at a constant speed for at least one full turn, continuously collecting the force value signal of the pressure sensor, and calculating the maximum force difference ΔF within one rotation cycle pp , ΔF pp is divided by the force-displacement relationship coefficient k to convert into the roundness error ΔF pp / k, which is compared with the preset roundness tolerance. If the roundness error does not exceed the preset roundness tolerance, the roundness is determined to be qualified; S6 multi-section measurement step: the plug gauge is respectively adjusted to different axial sections of the workpiece by the lifting adjustment unit, the S3 measurement step and the S4 outer diameter tolerance determination step are repeated, and the measured outer diameter values calculated for each section are compared to evaluate the taper of the workpiece; S7 unloading step: after all measurements are completed, stop the rotation of the rotary driving member, and after the rotation speed drops to zero, the vacuum adsorption is disconnected and the workpiece is taken out.

[0017] The beneficial effects of the present invention are: in the device for detecting outer diameter tolerance and roundness of a cylindrical workpiece provided by the present invention, (1) By organically integrating the feed force measuring unit, the lifting adjustment unit and the rotary positioning unit on the same frame, the integrated on-line detection of outer diameter tolerance and roundness is realized; the workpiece can complete two detection tasks with only one clamping, which improves the detection efficiency; the cooperative work of each functional unit provides a hardware foundation for fully automated on-line detection.

[0018] (2) An elastic member or elastic hinge structure is arranged between the plug gauge and the pressure sensor, so that the contact force between the plug gauge and the workpiece surface is precisely controlled and flexibly buffered, which fundamentally avoids the common problem of workpiece surface scratching in the traditional rigid contact measurement, and is especially suitable for on-line detection of finished or ultra-finished surfaces.

[0019] (3) The detection method of the present invention adopts the comparative measurement principle of calibration writing limit and force value comparison, does not require expensive grating rulers or high-precision displacement sensors, and can distinguish size variations at the 0.1μm level by utilizing the high sensitivity of the pressure sensor, realizing the unification of high precision and low cost.

[0020] (4) Through the cooperation of the lifting adjustment unit and the multi-section measurement method, it can not only adapt to the rapid type change of workpieces of different length specifications, but also perform multi-section scanning measurement on the same workpiece to evaluate the taper, which significantly improves the detection flexibility and adaptability of the device.

[0021] (5) The dual safety interlock logic combined with the safe feeding sequence means that rotation and feeding are prohibited at the same time when the vacuum is insufficient, which fully protects the safety of personnel and equipment during the testing process. Attached Figure Description

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Figure 2 This is a top view of the structure of the present invention; Figure 3 This is the present invention. Figure 2 Schematic diagram of the cross-sectional structure at point AA; Figure 4 This is the present invention. Figure 3 Enlarged structural diagram at point B; Figure 5 This is a schematic diagram of the right-side structure of the present invention; Figure 6 This is a schematic diagram of the workpiece-free three-dimensional structure of the present invention; Figure 7 This is the present invention. Figure 6 Enlarged structural diagram at point C; Figure 8 This is the present invention. Figure 2 Schematic diagram of the cross-sectional structure at point DD; Figure 9 This is a perspective structural diagram of the rotating fixture of the present invention.

[0024] In the diagram: 1. Frame; 2. Feed force measuring unit, 21. Fixed plate, 22. Push drive component, 23. Pressure sensor, 24. Positioning plate, 241. Mounting part, 242. Second groove, 243. Mounting groove, 244. Pressure plate, 245. Positioning pin, 25. Plug gauge, 251. Movable hole, 252. Contact part, 253. Elastic element, 26. Connecting plate, 261. First groove, 27. First slider, 28. First slide rail; 3. Lifting and adjusting unit; 31. Adjusting screw; 32. Base plate; 33. Lifting plate; 34. Second slider; 35. Second slide rail; 4. Rotary positioning unit; 41. Rotary drive component; 42. Rotary fixture; 421. Positioning cavity; 422. Adsorption hole; 423. Connecting part; 424. Suction cup; 425. Main air passage; 43. Bearing seat; 431. Sealing cavity; 432. Air inlet; 44. Coupling; 45. Rotary bearing; 46. Sealing ring; 47. Fixing component. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0026] like Figure 1 This is a schematic diagram of the structure of the present invention. A cylindrical workpiece outer diameter tolerance and roundness detection device includes a feed force measuring unit 2, a lifting adjustment unit 3 and a rotation positioning unit 4 arranged on a frame 1. The feed force measuring unit 2 includes a fixed plate 21, a push drive component 22, a pressure sensor 23, a positioning plate 24, and a plug gauge 25. The push drive component 22 is fixedly connected to the fixed plate 21. The push drive component 22 can be a cylinder. The output end of the push drive component 22 is connected to the pressure sensor 23. The pressure sensor 23 is fixedly connected to the positioning plate 24. The plug gauge 25 is elastically connected to the positioning plate 24. The push drive component 22 is used to provide power for the plug gauge 25 to move away from or closer to the workpiece. By organically integrating the feed force measuring unit 2, the lifting adjustment unit 3, and the rotary positioning unit 4 on the same frame 1, the integrated online detection of outer diameter tolerance and roundness is realized. The workpiece only needs to be clamped once to complete two detection tasks, which improves the detection efficiency. An elastic component or elastic hinge structure is set between the plug gauge 25 and the pressure sensor 23 to accurately control and flexibly buffer the contact force between the plug gauge 25 and the workpiece surface, which fundamentally avoids the workpiece surface scratch problem common in traditional rigid contact measurement. It is particularly suitable for online detection of finished or ultra-finished surfaces. The feed force measuring unit 2 includes a connecting plate 26, on which a first groove 261 is provided for placing a pressure sensor 23. The pressure sensor 23 is fitted into the first groove 261. The connecting plate 26 is arranged between the push drive member 22 and the pressure sensor 23, so that the pressure sensor 23 is fitted into the first groove 261 for positioning. This ensures the consistency between the force axis of the pressure sensor 23 and the output direction of the push drive member 22, improves the stability of force transmission and measurement repeatability, and facilitates the quick installation and replacement of the pressure sensor 23.

[0027] Furthermore, the pressure sensor 23 and the connecting plate 26 can be fixed by bolts or welding to strengthen the connection.

[0028] like Figure 1 , 2As shown, a mounting portion 241 protrudes from the positioning plate 24, and a second groove 242 is provided on the mounting portion 241 for placing the pressure sensor 23. The pressure sensor 23 is arranged in the second groove 242, so that the pressure sensor 23 is fitted into the second groove 242 to achieve precise positioning, ensuring the coaxiality of the pressure sensor 23 and the positioning plate 24, so that the elastic reaction force can be transmitted to the sensitive element of the pressure sensor 23 without damage or eccentricity, further improving the measurement accuracy.

[0029] Furthermore, the pressure sensor 23 and the positioning plate 24 can be fixed by bolts or welding to strengthen the connection.

[0030] The positioning plate 24 has an installation groove 243, and the plug gauge 25 is slidably arranged in the installation groove 243; like Figure 3 , 4 As shown, an elastic element 253 is arranged in the mounting groove 243. One end of the elastic element 253 abuts against the positioning plate 24, and the other end abuts against the plug gauge 25, so that the plug gauge 25 and the positioning plate 24 form an elastic connection. This not only achieves flexible buffering when the plug gauge 25 contacts the workpiece, avoiding damage to the workpiece surface and impact damage to the pressure sensor 23, but also follows Hooke's Law to convert the dimensional deviation of the workpiece into elastic reaction force changes with high precision, providing core structural support for the comparative measurement principle of fixed feed force value detection.

[0031] The elastic element 253 is a compression spring or an elastic hinge.

[0032] The feed force measuring unit 2 includes a pressure plate 244 and a positioning pin 245. The pressure plate 244 and the positioning plate 24 are fixedly connected on their top surfaces, and the mounting groove 243 is located on the top surface of the positioning plate 24. The plug gauge 25 has a movable hole 251, which is an oblong hole extending along the extension direction of the mounting groove 243. The positioning pin 245 passes through the pressure plate 244 and extends into the movable hole 251. Through the cooperation between the pressure plate 244 and the positioning pin 245, the positioning pin 245 passes through the pressure plate 244 and extends into the movable hole 251 of the plug gauge 25. This ensures that the plug gauge 25 can slide freely only along the extension direction of the mounting groove 243, and also limits the sliding stroke range of the plug gauge 25 to prevent the plug gauge 25 from falling out. At the same time, the pressure plate 244 and the positioning plate 24 are detachably connected, which is convenient for disassembly and assembly and facilitates the replacement and maintenance of the elastic element 253.

[0033] The plug gauge 25 has an arc-shaped contact portion 252 at one end near the workpiece, which enables the plug gauge 25 to form a stable point contact or small-area line contact with the outer surface of the cylindrical workpiece. The contact position does not change with the diameter of the workpiece, ensuring a strict linear relationship between the change of the measuring force and the change of the measured dimension, thus improving the measurement accuracy and repeatability.

[0034] The feed force measuring unit 2 includes a first slider 27 and a first slide rail 28 that matches the first slider 27. The first slider 27 is fixedly connected to the positioning plate 24, the first slide rail 28 is fixedly connected to the fixing plate 21, and the first slider 27 and the first slide rail 28 are slidably connected. Through the sliding cooperation between the first slider 27 and the first slide rail 28, the positioning plate 24 and the plug gauge 25 move in a fixed direction with high precision, ensuring the consistency of each feed to the limit position, reducing the interference of frictional resistance and movement deviation on the force value measurement, and improving the repeatability and long-term stability of the detection.

[0035] The output end of the lifting adjustment unit 3 is fixedly connected to the fixed plate 21. The lifting adjustment unit 3 is used to provide power for the height adjustment of the feed force measuring unit 2. The lifting adjustment unit 3 includes an adjusting screw 31, a base plate 32, a lifting plate 33, a second slider 34, and a second slide rail 35. The second slide rail 35 is fixedly connected to the frame 1, the second slider 34 is slidably connected to the second slide rail 35, and the second slider 34 is fixedly connected to the lifting plate 33. The substrate 32 and the frame 1 are fixedly connected; The adjusting screw 31 and the base plate 32 are rotatably connected, and the adjusting screw 31 and the lifting plate 33 are threadedly connected. By rotating the handwheel or driving the servo motor to rotate the adjusting screw 31 through the threaded connection between the adjusting screw 31 and the lifting plate 33, the lifting plate 33 and the feed force measuring unit 2 fixed on it can be smoothly raised and lowered. The second slider 34 and the second slide rail 35 cooperate to provide high-precision guidance, and the base plate 32 provides stable support for the adjusting screw 31. The manual mode is suitable for type change adjustment, and a servo drive driven by a motor can also be added to the adjusting screw 31 to realize automatic scanning measurement of multiple preset sections. The structure is simple and reliable, with high adjustment accuracy and strong adaptability.

[0036] The rotary positioning unit 4 is used to place the workpiece and provide power for the rotation of the workpiece.

[0037] like Figure 6 , 7 As shown, the rotary positioning unit 4 includes a rotary drive 41, a rotary fixture 42, and a transmission assembly. The transmission assembly includes a bearing housing 43, a coupling 44, a rotating bearing 45, a sealing ring 46, and a fixing component 47. The bearing housing 43 is fixedly connected to the frame 1. The bottom of the rotating jig 42 protrudes to form a connecting part 423. The connecting part 423 passes through the bearing seat 43 and is connected to the rotating drive member 41 through the coupling 44. The rotating drive member 41 is fixedly connected to the frame 1. The rotating drive member 41 is used to provide power for the rotation of the rotating jig 42. The fixing part 47 and the connecting part 423 are threaded together. The fixing part 47 is located below the bearing seat 43. The fixing part 47 can be a nut. It cooperates with the structure of the rotating jig 42 pressing the inner ring of the upper rotating bearing 45. At the same time, it realizes the pre-tightening of the rotating bearing 45 and the axial positioning of the rotating jig 42, ensuring the stability and accuracy of the workpiece rotation measurement. The bearing housing 43 has a sealing cavity 431 surrounding the connecting part 423, and the bearing housing 43 has an air inlet 432 communicating with the sealing cavity 431. The air inlet 432 is connected to the air pump. Rotary bearing 45 is arranged at the end of bearing housing 43 and is sleeved on connecting part 423; The sealing ring 46 is fitted on the connecting part 423, and the sealing ring 46 is located between the rotating bearing 45 and the sealing cavity 431 on its side. The sealing ring 46 is used to seal the gap where the connecting part 423 passes through the sealing cavity 431. Through the reasonable arrangement of the sealing cavity 431 opened in the bearing seat 43, the stationary air inlet 432, the main air passage 425 in the connecting part 423, and the sealing ring 46, the vacuum transfer of the stationary air source and the rotating fixture is cleverly realized. There is no need for an external rotating joint, which greatly simplifies the structure, reduces leakage points, and improves the reliability and long-term stability of vacuum adsorption. The rotating jig 42 and the frame 1 are rotatably connected. The top surface of the rotating jig 42 is provided with a positioning cavity 421 for placing the workpiece. The workpiece boss is nested in the positioning cavity 421 to achieve precise mechanical positioning. The connecting part 423 is provided with a main air passage 425 that communicates with the sealed cavity 431. The rotating jig 42 is provided with an adsorption hole 422. A portion of the adsorption hole 422 is located on the top surface of the rotating jig 42. A suction cup 424 is arranged in the adsorption hole 422 located on the top surface of the rotating jig 42. A portion of the adsorption hole 422 is located at the bottom of the positioning cavity 421. The adsorption hole 422 is connected to the main air passage 425.

[0038] like Figure 6 , 9 As shown, the outer peripheral wall of the rotating jig 42 has an opening. The section of the opening away from the inner side of the rotating jig 42 is a machining hole. When the rotating jig 42 is working, a plug is installed in the machining hole to seal it, so as to prevent the adsorption hole 422 from failing to generate sufficient adsorption force to adsorb the workpiece. The section of the opening near the inner side of the rotating jig 42 allows the adsorption hole 422 to be connected to the main air passage 425.

[0039] A method for detecting the outer diameter tolerance and roundness of a cylindrical workpiece using a measuring device includes the following steps: S1 limit calibration step: adjust the plug gauge 25 to the height of the target measurement section of the standard cylindrical workpiece through the lifting adjustment unit 3, place the standard cylindrical workpiece on the rotary positioning unit 4 for adsorption and fixation, push the driving member 22 to drive the plug gauge 25 to contact the outer cylindrical surface of the standard cylindrical workpiece, adjust the position of the mechanical limit structure provided on the pushing driving member 22 to make the reading of the pressure sensor 23 fall within the preset target force value range, record the current stable reading of the pressure sensor 23 as the reference force value F0, and record the current limit position as the reference position; On the basis of the reference position, adjust the mechanical limit structure to two different positions respectively, which are in front of and behind the reference position, record the stable reading of the pressure sensor 23 and the corresponding stroke variation Δx at each position, and calculate the force-displacement relationship coefficient k=ΔF / Δx according to the force value variation ΔF and the stroke variation Δx; the core of calibration is to write the outer diameter dimension of the standard workpiece into the mechanical limit, make the reading of the pressure sensor 23 fall near the mid-range value by adjusting the limit, all subsequent workpieces to be measured are measured at the same stroke end point, and the dimensional deviation is completely reflected by the change of the deformation amount of the elastic element 253. The k value is actually calibrated through the force values and stroke changes at the two front and rear limit positions, which comprehensively reflects the response characteristics of the elastic element 253, the pressure sensor 23 and the entire transmission chain, and is not a theoretically preset value.

[0040] S2 workpiece loading and safety detection step: remove the standard cylindrical workpiece, place the cylindrical workpiece to be measured on the rotary positioning unit 4, make the boss at the bottom of the workpiece embedded into the positioning cavity 421 of the rotary positioning unit 4 to realize central positioning, start vacuum adsorption to fix the workpiece to be measured, monitor the adsorption vacuum degree through a negative pressure detection sensor, the negative pressure detection sensor can be arranged in the main air passage 425 or the adsorption hole 422, if the vacuum degree is lower than the set threshold, the rotary driving member 41 is prohibited from starting, and the pushing driving member 22 is prohibited from feeding at the same time; S3 measurement step: adjust the plug gauge 25 to the same height as in S1 through the lifting adjustment unit 3, after the adsorption vacuum degree meets the set requirement, the pushing driving member 22 feeds to the limit position with the reference position as the target, the plug gauge 25 contacts the outer cylindrical surface of the cylindrical workpiece to be measured, and the pressure sensor 23 outputs a stable force value F x ; S4 outer diameter tolerance judgment step: according to the force-displacement relationship coefficient k obtained by calibration, calculate the outer diameter deviation value ΔD=(F x -F0) / k of the workpiece to be measured at this section, the measured outer diameter value D=D0+ΔD, where D0 is the nominal outer diameter value of the standard cylindrical workpiece, compare the measured outer diameter value D with the nominal outer diameter value D0 of the standard cylindrical workpiece and the preset tolerance range, if D0-T≤D≤D0+T, it is judged that the outer diameter of this section is qualified, if D>D0+T, it is judged that the outer diameter is too large, and if D<D0-T, it is judged that the outer diameter is too small; S5 Roundness Judgment Steps: Drive the rotary positioning unit 4 to rotate the workpiece at a constant speed for at least one revolution, continuously collect the force value signal from the pressure sensor 23, and calculate the maximum difference in force value ΔF within one rotation cycle. pp , will ΔF pp Divide by the force-displacement coefficient k to convert to roundness error ΔF pp / k is compared with the preset roundness tolerance. If the roundness error does not exceed the preset roundness tolerance, the roundness is deemed to be qualified. S6 Multi-section Measurement Steps: Adjust the plug gauge 25 to different axial sections of the workpiece using the lifting adjustment unit 3, repeat the S3 measurement steps and the S4 outer diameter tolerance judgment steps, and compare the actual measured outer diameter values ​​calculated for each section to evaluate the taper of the workpiece; The lifting adjustment unit 3 has dual functions: (1) type change adjustment to adapt to workpieces of different length specifications; (2) multi-section scanning measurement to evaluate the taper of the same workpiece by measuring the upper, middle and lower sections. The lifting adjustment is both a type change method and a multi-section measurement method, and the two functions together support the detection flexibility of the device.

[0041] S7 Unloading Steps: After completing all measurements, stop the rotation of the drive component 41. After the rotation speed drops to zero, disconnect the vacuum adsorption and remove the workpiece.

[0042] Working process: (I) Limit calibration The operator uses the lifting adjustment unit 3 to rotate the adjusting screw 31 to drive the lifting plate 33 to rise and fall along the second slide rail 35, thereby adjusting the entire feed force measuring unit 2 to the target measurement section height of the standard cylindrical workpiece.

[0043] Take a standard cylindrical workpiece with an outer diameter of nominal value D0 and place it on the rotating jig 42. The bottom end face of the workpiece is in contact with the top surface of the rotating jig 42. If the workpiece has a boss structure, the boss is embedded in the positioning cavity 421 to achieve center positioning. Start the vacuum generator. The negative pressure is transmitted sequentially through the stationary air inlet 432 on the bearing seat 43, the sealed cavity 431, and the main air passage 425 in the connecting part 423, and finally to the adsorption hole 422 on the top surface of the rotating jig 42 and the adsorption hole 422 at the bottom of the positioning cavity 421. The standard workpiece is fixed on the rotating jig 42 by suction cup 424 or direct adsorption.

[0044] The drive unit 22 is activated, and its output end drives the plug gauge 25 towards the standard workpiece via the pressure sensor 23 and the positioning plate 24 until the contact portion 252 of the plug gauge 25 contacts the outer cylindrical surface of the standard workpiece. The operator adjusts the position of the limiting screw located at the tail of the drive unit 22 so that the reading of the pressure sensor 23 is within the preset target force value range, preferably 30%-70% of the sensor's range. The limiting screw is then tightened to fix the end position of the stroke. The current stable reading of the pressure sensor 23 is recorded as the reference force value F0, and the current limiting position is recorded as the reference position.

[0045] Based on this, the mechanical limit structure is adjusted to two different positions, one in front of the reference position and one behind it. At each position, the stable reading of the pressure sensor 23 and the corresponding stroke change Δx are recorded. The force-displacement relationship coefficient k=ΔF / Δx is calculated based on the force change ΔF and the stroke change Δx. This coefficient reflects the actual stiffness characteristics of the elastic element 253.

[0046] Force-displacement relationship coefficient calibration: Based on the aforementioned reference position, the mechanical limit structure is adjusted to two different positions. For example, the stroke is increased by a known small amount Δx1 and Δx2 based on the reference position. The value of Δx is preferably 0.005mm-0.02mm. The stable readings F1 and F2 of the pressure sensor 23 and the corresponding stroke changes Δx1 and Δx2 are recorded at each position. The force-displacement relationship coefficient k = ΔF / Δx is calculated based on the force change ΔF and the stroke change Δx. This coefficient k comprehensively reflects the force-displacement response characteristics of the elastic element 253, the pressure sensor 23, and the entire transmission chain, and is more accurate and reliable than the theoretical stiffness value. Preferably, more than three positions can be selected for linear fitting to further improve the calibration accuracy of the k value.

[0047] The outer diameter of the standard workpiece is written into the mechanical limit structure, so that the drive component 22 always feeds at the same end point of the stroke during subsequent measurement. The deviation of the workpiece outer diameter is reflected only by the change in the deformation of the elastic element 253, thereby converting the dimensional deviation into a change in force value with high precision.

[0048] (II) Assembly and Safety Inspection Remove the standard cylindrical workpiece and place the cylindrical workpiece to be tested onto the rotating fixture 42. The boss at the bottom of the workpiece is embedded in the positioning cavity 421 of the rotating fixture 42 to achieve center positioning. For workpieces without bosses, they are placed directly on the top surface of the rotating fixture 42 and positioned by suction cup 424. Start vacuum suction to fix the workpiece to be tested.

[0049] The negative pressure detection sensor monitors the adsorption vacuum degree in real time, and the control system determines whether the adsorption vacuum degree is lower than a set threshold. If it is lower than the set threshold, the safety interlock logic simultaneously executes two prohibiting actions: prohibiting the rotation driving member 41 from starting to prevent the workpiece from being thrown out during rotation, and prohibiting the pushing driving member 22 from feeding to prevent contact measurement when the workpiece is not fixed, so as to avoid workpiece offset or sensor impact. Only after the vacuum degree meets the set requirement is the next measurement step allowed to proceed.

[0050] (3) Measurement The height of the gauge plug 25 is adjusted by the lifting adjustment unit 3 to the same measurement section height as that calibrated in S1, so as to ensure the consistency of the measurement section. After the adsorption vacuum degree meets the set requirement, the pushing driving member 22 feeds to the limit position with the reference position recorded in S1 as the target. The mechanical limit structure has been fixed at the reference position, so that the contact portion 252 of the gauge plug 25 comes into contact with the outer circular surface of the cylindrical workpiece to be measured.

[0051] If there is a deviation between the outer diameter of the workpiece to be measured and the standard part, the compression amount of the elastic element 253 will change accordingly. The pressure sensor 23 detects the elastic reaction force, and outputs a stable force value F after the force value stabilizes x .

[0052] (4) Outer diameter tolerance determination The control system calculates the outer diameter deviation value of the workpiece to be measured at this section according to the force-displacement relationship coefficient k obtained by calibration in S1: ΔD=(F x -F0) / k The measured outer diameter value D=D0+ΔD where D0 is the nominal outer diameter value of the standard cylindrical workpiece. The measured outer diameter value D is compared with the preset tolerance range [D0-T, D0+T], and the determination logic is as follows: If D0-T≤D≤D0+T, it is determined that the outer diameter of this section is qualified; If D>D0+T, it is determined that the outer diameter is too large (upper out-of-tolerance); If D<D0-T, it is determined that the outer diameter is too small (lower out-of-tolerance).

[0053] (5) Roundness determination On the basis of outer diameter measurement, the rotation driving member 41 is driven to start. The rotation driving member 41 drives the connecting portion 423 and the rotating jig 42 to rotate at a constant speed for at least one revolution through the coupling 44. During the constant-speed rotation of the workpiece, the data acquisition card continuously collects the force value fluctuation signal of the pressure sensor 23 at a high frequency (preferably ≥1kHz).

[0054] The control system calculates the difference ΔF between the maximum force value F_max and the minimum force value F_min within one complete rotation cycle pp =F_max-F_min, and ΔFpp Divide by the force-displacement coefficient k to convert to roundness error: Roundness = ΔF pp / k The calculated roundness error is compared with the preset roundness tolerance. If the roundness error does not exceed the preset roundness tolerance, the roundness of the cross section is deemed to be qualified; if it exceeds the threshold, the roundness is deemed to be unqualified.

[0055] (vi) Multi-section measurement When it is necessary to evaluate the taper or cylindricity of a workpiece, the feed measuring unit 2 is raised and lowered as a whole by the lifting adjustment unit 3. Rotating the adjusting screw 31 moves the lifting plate 33 along the second slide rail 35, positioning the plug gauge 25 at three or more different axial sections of the workpiece (upper, middle, and lower). At each section height, the S3 measurement step and the S4 outer diameter tolerance judgment step are repeated to obtain the measured outer diameter value of each section. By comparing the measured outer diameter values ​​of each section, the taper of the workpiece can be quantitatively evaluated, such as the difference in outer diameter between the upper and lower sections, providing a more comprehensive evaluation basis for the workpiece machining quality.

[0056] By comparing the outer diameter deviation data of each section, the taper or cylindricity of the workpiece can be quantitatively assessed. Taper = (D_upper - D_lower) / L; Where D_upper and D_lower are the measured outer diameters of the upper and lower sections, respectively, and L is the axial distance between the two sections.

[0057] Multi-section measurement not only enables the comparison of dimensional deviations at different axial positions on the same workpiece, but also allows for rapid adjustment of the measurement height when changing workpieces of different lengths, significantly improving the device's detection flexibility and adaptability.

[0058] (vii) Material feeding After the inspection is completed, the control system executes a safe unloading sequence: First, the rotation of the drive component 41 is stopped. After the speed drops to zero, the vacuum adsorption is disconnected or positive pressure blowing is applied to assist in unloading. The operator or robot arm removes the workpiece. The drive component 22 is then pushed to reset, awaiting the next workpiece inspection cycle. This sequence ensures that the workpiece will not fly out due to rotational inertia before the adsorption is released, guaranteeing the safety of personnel and equipment.

[0059] Throughout the entire working process described above, the working principle of the vacuum adsorption gas path of the rotating fixture 42 is as follows: The negative pressure generated by the external vacuum generator enters the sealed cavity 431 through the stationary air inlet 432 on the bearing seat 43. The sealing ring 46 ensures the sealing of both ends of the sealed cavity 431, allowing the negative pressure to be stably maintained within the sealed cavity 431. The negative pressure enters the main air passage 425 inside the connecting part 423 through the through hole, and then is conducted upwards to the adsorption holes 422 inside the rotating fixture 42. Finally, an adsorption force is generated on the top surface of the rotating fixture 42 and the bottom of the positioning cavity 421, firmly adsorbing the workpiece. During the entire rotation process, the negative pressure in the sealed cavity 431 remains stable, realizing a continuous vacuum supply from the stationary gas source to the rotating component.

[0060] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A device for detecting the outer diameter tolerance and roundness of a cylindrical workpiece, characterized in that, It includes a feed force measuring unit (2), a lifting adjustment unit (3), and a rotation positioning unit (4) arranged on the frame (1); The feed force measuring unit (2) includes a fixed plate (21), a push drive (22), a pressure sensor (23), a positioning plate (24), and a plug gauge (25). The push drive (22) and the fixed plate (21) are fixedly connected. The output end of the push drive (22) is connected to the pressure sensor (23) via a transmission. The pressure sensor (23) and the positioning plate (24) are fixedly connected. The plug gauge (25) and the positioning plate (24) are elastically connected. The push drive (22) is used to provide power for the plug gauge (25) to move away from or closer to it. The output end of the lifting adjustment unit (3) is fixedly connected to the fixed plate (21), and the lifting adjustment unit (3) is used to provide power for the height adjustment of the feed force measuring unit (2); The rotary positioning unit (4) is used to place the workpiece and provide power for the rotation of the workpiece.

2. The device for detecting the outer diameter tolerance and roundness of a cylindrical workpiece as described in claim 1, characterized in that: The feed force measuring unit (2) includes a connecting plate (26), on which a first groove (261) is provided for placing a pressure sensor (23). The pressure sensor (23) is fitted into the first groove (261), and the connecting plate (26) is arranged between the push drive member (22) and the pressure sensor (23).

3. The device for detecting the outer diameter tolerance and roundness of a cylindrical workpiece as described in claim 2, characterized in that: The positioning plate (24) has a protruding mounting portion (241), and the mounting portion (241) has a second groove (242) for placing the pressure sensor (23), and the pressure sensor (23) is arranged in the second groove (242).

4. The device for detecting the outer diameter tolerance and roundness of a cylindrical workpiece as described in claim 1, characterized in that: The positioning plate (24) has an installation groove (243), and the plug gauge (25) is slidably arranged in the installation groove (243); An elastic element (253) is arranged in the mounting groove (243), with one end of the elastic element (253) abutting against the positioning plate (24) and the other end abutting against the plug gauge (25).

5. The device for detecting the outer diameter tolerance and roundness of a cylindrical workpiece as described in claim 4, characterized in that: The feed force measuring unit (2) includes a pressure plate (244) and a positioning pin (245). The pressure plate (244) and the positioning plate (24) are fixedly connected on their top surfaces, and the mounting groove (243) is located on the top surface of the positioning plate (24). The plug gauge (25) has a movable hole (251), which is a waist-shaped hole extending along the extension direction of the mounting groove (243). The positioning pin (245) passes through the pressure plate (244) and extends into the movable hole (251).

6. The device for detecting the outer diameter tolerance and roundness of a cylindrical workpiece as described in claim 1, characterized in that: The plug gauge (25) has an arc-shaped contact portion (252) on one end near the workpiece.

7. The device for detecting the outer diameter tolerance and roundness of a cylindrical workpiece as described in claim 1, characterized in that: The feed force measuring unit (2) includes a first slider (27) and a first slide rail (28) that matches the first slider (27). The first slider (27) and the positioning plate (24) are fixedly connected. The first slide rail (28) and the fixing plate (21) are fixedly connected. The first slider (27) and the first slide rail (28) are slidably connected.

8. The device for detecting the outer diameter tolerance and roundness of a cylindrical workpiece as described in claim 1, characterized in that: The lifting adjustment unit (3) includes an adjustment screw (31), a base plate (32), a lifting plate (33), a second slider (34), and a second slide rail (35); The second slide rail (35) is fixedly connected to the frame (1), the second slider (34) is slidably connected to the second slide rail (35), and the second slider (34) is fixedly connected to the lifting plate (33); The substrate (32) and the frame (1) are fixedly connected; The adjusting screw (31) and the base plate (32) are rotatably connected, and the adjusting screw (31) and the lifting plate (33) are threadedly connected.

9. The device for detecting the outer diameter tolerance and roundness of a cylindrical workpiece as described in claim 1, characterized in that: The rotary positioning unit (4) includes a rotary drive (41), a rotary fixture (42), and a transmission assembly; The transmission assembly includes a bearing housing (43), a coupling (44), a rotating bearing (45), a sealing ring (46), and a fixing member (47), wherein the bearing housing (43) and the frame (1) are fixedly connected. The bottom of the rotating jig (42) has a protruding connecting part (423). The connecting part (423) passes through the bearing seat (43) and is connected to the rotating drive (41) via a coupling (44). The rotating drive (41) is fixedly connected to the frame (1). The rotating drive (41) is used to provide power for the rotation of the rotating jig (42). The fastener (47) and the connecting part (423) are threaded together, and the fastener (47) is located below the bearing seat (43); The bearing housing (43) has a sealed cavity (431) surrounding the connecting part (423) and an air inlet (432) communicating with the sealed cavity (431) on the bearing housing (43). The rotating bearing (45) is arranged at the end of the bearing housing (43) and the rotating bearing (45) is sleeved on the connecting part (423); The sealing ring (46) is fitted on the connecting part (423), and the sealing ring (46) is located between the rotating bearing (45) and the sealing cavity (431) on its side. The sealing ring (46) is used to seal the gap where the connecting part (423) passes through the sealing cavity (431). The rotating jig (42) and the frame (1) are rotatably connected. The top surface of the rotating jig (42) is provided with a positioning cavity (421) for placing the workpiece. The connecting part (423) is provided with a main air passage (425) that communicates with the sealed cavity (431). The rotating jig (42) is provided with an adsorption hole (422). A portion of the adsorption hole (422) is located on the top surface of the rotating jig (42). A suction cup (424) is arranged in the adsorption hole (422) on the top surface of the rotating jig (42). A portion of the adsorption hole (422) is located at the bottom of the positioning cavity (421). The adsorption hole (422) is connected to the main air passage (425).

10. A method for detecting the outer diameter tolerance and roundness of a cylindrical workpiece using any one of claims 1-9, characterized in that: Includes the following steps: S1 Limit Calibration Steps: Adjust the plug gauge (25) to the target measurement section height of the standard cylindrical workpiece through the lifting adjustment unit (3), place the standard cylindrical workpiece on the rotary positioning unit (4) for adsorption and fixation, push the drive component (22) to drive the plug gauge (25) to contact the outer circle surface of the standard cylindrical workpiece, adjust the position of the mechanical limit structure set on the push drive component (22) so that the reading of the pressure sensor (23) is within the preset target force value range, record the current stable reading of the pressure sensor (23) as the reference force value F0, and record the current limit position as the reference position; Based on the reference position, the mechanical limit structure is adjusted to two different positions respectively, and the stable reading of the pressure sensor (23) and the corresponding stroke change Δx are recorded at each position. The force-displacement relationship coefficient k = ΔF / Δx is calculated based on the force change ΔF and the stroke change Δx. S2 Assembly and Safety Inspection Steps: Remove the standard cylindrical workpiece, place the cylindrical workpiece to be tested on the rotary positioning unit (4), so that the boss at the bottom of the workpiece is embedded in the positioning cavity (421) of the rotary positioning unit (4) to achieve center positioning, start vacuum adsorption to fix the workpiece to be tested, monitor the adsorption vacuum degree through the negative pressure detection sensor, if it is lower than the set threshold, the rotary drive (41) is prohibited from starting, and the drive (22) is prohibited from being pushed to feed. S3 Measurement Steps: Adjust the plug gauge (25) to the same height as in S1 using the lifting adjustment unit (3). After the adsorption vacuum meets the set requirements, push the drive component (22) to feed to the limit position with the reference position as the target. The plug gauge (25) contacts the outer surface of the cylindrical workpiece to be measured, and the pressure sensor (23) outputs a stable force value F. x ; Step S4 for determining outer diameter tolerance: According to the force-displacement relationship coefficient k obtained by calibration, calculate the outer diameter deviation value ΔD of the workpiece to be measured at this cross-section as ΔD=(F x -F0) / k, and the measured outer diameter value D=D0+ΔD, where D0 is the nominal outer diameter value of the standard cylindrical workpiece. The measured outer diameter value D is compared with the nominal outer diameter value D0 of the standard cylindrical workpiece and the preset tolerance range. If D0-T≤D≤D0+T, it is determined that the outer diameter of this cross-section is qualified; if D>D0+T, it is determined that the outer diameter is too large; if D<D0-T, it is determined that the outer diameter is too small; S5 Roundness Judgment Steps: Drive the rotary positioning unit (4) to rotate the workpiece at a constant speed for at least one revolution, continuously collect the force value signal from the pressure sensor (23), and calculate the maximum difference in force value ΔF within one rotation cycle. pp , will ΔF pp Divide by the force-displacement coefficient k to convert to roundness error ΔF pp / k is compared with the preset roundness tolerance. If the roundness error does not exceed the preset roundness tolerance, the roundness is deemed to be qualified. S6 Multi-section measurement steps: Adjust the plug gauge (25) to different axial sections of the workpiece by lifting and adjusting the lifting unit (3), repeat the S3 measurement steps and S4 outer diameter tolerance judgment steps, and compare the actual measured outer diameter values ​​calculated for each section to evaluate the taper of the workpiece. S7 unloading steps: After completing all measurements, stop the rotation drive (41) from rotating. After the speed drops to zero, disconnect the vacuum adsorption and take out the workpiece.

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