Method and device for detecting pitch diameter of nut inner raceway

Abstract

The application relates to the technical field of nut detection, in particular to a nut inner raceway pitch diameter detection method and device. The method comprises the following steps: grinding the spiral raceway of the nut clamped on the grinding machine to complete pre-grinding, determining the ball diameter of a ball module according to the target size parameter of the spiral raceway; assembling the ball module to the outer peripheral wall of a variable-diameter module; extending the variable-diameter module into the interior of the nut and making the variable-diameter module coaxial with the nut; gradually increasing the diameter of the variable-diameter module, and rotating and moving the variable-diameter module along the extension direction of the spiral raceway until the three measuring balls abut against the spiral raceway; obtaining the circumferential diameter determined by the ball centers of the three measuring balls to complete one measurement. In this way, the problems that the on-line special detection tool of the nut inner raceway has poor universality, can only be adapted to single-specification products, off-line high-precision detection cannot be returned to work due to the loss of positioning reference after disassembly, can only scrap the workpiece, causes material and working hour loss and drags the production efficiency are solved.

Description

Technical Field

[0001] This application relates to the field of nut testing technology, and more specifically, to a method and apparatus for testing the pitch circle diameter of the inner raceway of a nut. Background Technology

[0002] The inner raceway of the nut is the core transmission component of the ball screw assembly. Its dimensional accuracy, shape accuracy, and surface quality directly determine the transmission accuracy, operational smoothness, and service life of the ball screw assembly. Currently, the machining and inspection of the inner raceway of the nut adopts a step-by-step process. First, the nut is clamped on a CNC grinding machine, and the grinding wheel of the machine is used to precision grind the inner raceway to obtain a raceway surface that meets the design requirements. After machining, the industry mainly uses two inspection methods to verify the accuracy of the inner raceway: one is online inspection, which keeps the nut in the clamped state on the machine tool and measures the key dimensional parameters of the inner raceway using a special inspection tool installed on the grinding machine spindle or tool post; the other is offline inspection, which involves removing the ground nut from the grinding machine and transferring it to a coordinate measuring machine, profilometer, or other specialized precision inspection equipment to perform comprehensive geometric and shape accuracy inspection of the inner raceway.

[0003] In online inspection, the structure and measurement parameters of dedicated inspection tools are custom-designed for the internal raceway characteristics of a single-specification nut, making them unsuitable for the inspection needs of nuts of different specifications and models, resulting in extremely poor versatility. While offline inspection offers high accuracy and wide applicability, the original clamping and positioning reference is completely lost once the nut is removed from the machine tool. When the inspection results show that the internal raceway size or shape of the nut does not meet the standard requirements, it is impossible to re-clamp the nut back onto the grinding machine and restore it to its previous precise machining position for rework correction. Instead, the defective nut must be scrapped, resulting in a serious waste of raw materials and processing time, while also reducing production efficiency. Summary of the Invention

[0004] To address the issues of poor versatility of online dedicated inspection tools for the inner raceway of nuts, which can only be adapted to a single product specification, and the inability to rework offline high-precision inspection due to the loss of positioning reference after disassembly, resulting in scrapped workpieces, material and time losses, and reduced production efficiency, this application provides a method and device for detecting the pitch circle diameter of the inner raceway of nuts.

[0005] In a first aspect, this application provides a method for detecting the pitch circle diameter of the inner raceway of a nut, the method comprising:

[0006] Pre-grinding is completed on the helical raceway of the nut clamped on the grinding machine. The diameter of the ball module is determined according to the target size parameters of the helical raceway. The ball module includes three measuring balls. The diameter of the ball is the diameter of the measuring ball.

[0007] The spherical module is assembled onto the outer peripheral wall of the variable diameter module; wherein, with the spherical module assembled onto the variable diameter module, the three measuring balls are evenly distributed along the circumferential direction of the variable diameter module, and the three measuring balls are spaced apart along the axial direction of the variable diameter module;

[0008] The diameter-changing module is inserted into the interior of the nut, and the diameter-changing module is coaxial with the nut.

[0009] The diameter of the variable diameter module is gradually increased while the variable diameter module is rotated and moved along the extension direction of the spiral raceway until the three measuring balls respectively abut against the spiral raceway.

[0010] When all three measuring balls abut against the spiral raceway, the circumferential diameter determined by the centers of the three measuring balls is obtained, thus completing one measurement.

[0011] Optionally, the sphere module further includes three insert rods; each insert rod is fixedly connected to a measuring ball in a one-to-one correspondence; two measuring balls are located at the ends of the insert rods, and the other measuring ball is located in the middle of the insert rod; the variable diameter module has slots that correspond to each insert rod; the insert rods are movably inserted into the slots; the axis of the slots is parallel to the axis of the variable diameter module.

[0012] The process of assembling the spherical module onto the outer peripheral wall of the variable diameter module includes:

[0013] The measuring ball located in the middle of the insertion rod is assembled to the outer peripheral wall of the variable diameter module;

[0014] The two measuring balls located at the ends of the insert rods are assembled to the outer peripheral wall of the variable diameter module;

[0015] With the three measuring balls assembled into the diameter-changing module, the measuring ball located in the middle of the insert rod is positioned between the other two measuring balls along the axial direction of the diameter-changing module.

[0016] Optionally, the detection method further includes:

[0017] Once a measurement is completed, the number of measurements corresponding to the diameter of the sphere is accumulated.

[0018] The step of assembling the two measuring balls located at the ends of the insert rods to the outer peripheral wall of the variable diameter module includes:

[0019] When the number of measurements corresponding to the diameter of the ball is less than the first preset number, the two measuring balls located at the ends of the insert rod are arranged in a first position order along the axial spacing of the variable diameter module.

[0020] When the number of measurements corresponding to the diameter of the ball reaches the first preset number, the two measuring balls located at the ends of the insert rod are arranged along the axial spacing of the variable diameter module in a second position order; the first position order is the opposite of the second position order.

[0021] Optionally, assembling the measuring ball located in the middle of the insertion rod to the outer peripheral wall of the diameter-changing module includes:

[0022] When the number of measurements corresponding to the diameter of the ball is less than the second preset number, the measuring ball located in the middle of the insertion rod is assembled to the outer peripheral wall of the variable diameter module with the first orientation.

[0023] When the number of measurements corresponding to the diameter of the ball reaches the second preset number, the measuring ball located in the middle of the insertion rod is assembled to the outer peripheral wall of the variable diameter module in the second orientation.

[0024] During the process of the variable diameter module extending into the nut, the side of the measuring ball facing the nut is the abutting side; the abutting sides corresponding to the first orientation and the second orientation are the opposite sides of the measuring ball.

[0025] Optionally, the outer peripheral wall of the variable diameter module is provided with clearance openings that correspond one-to-one with the slots; when the ball module is assembled into the variable diameter module, the measuring ball located in the middle of the insert rod and at least one other measuring ball pass through the clearance openings and connect to the insert rod.

[0026] When the lead of the helical raceway is greater than the threshold, the measuring ball closest to the nut is suspended outside the variable diameter module;

[0027] The first preset number of times is less than the second preset number of times.

[0028] Optionally, assembling the sphere module onto the outer peripheral wall of the variable diameter module further includes:

[0029] The number of pads in the two target slots is adjusted according to the lead of the spiral raceway, and the position of the measuring ball located in the middle of the insert is kept constant, so that the distance between two adjacent measuring balls in the axial direction of the variable diameter module is 1 / 3 of the lead; wherein, the target slot is the slot where the insert with the measuring ball at the end is located; the pads are held between the bottom wall of the slot and the insert.

[0030] Secondly, this application provides a device for detecting the pitch circle diameter of the inner raceway of a nut, applied to the method for detecting the pitch circle diameter of the inner raceway of a nut as described in any one of the first aspects; the detection device includes:

[0031] Positioning axis;

[0032] A diameter-changing module is coaxially arranged with the positioning shaft; the diameter-changing module includes a drive unit and three adjusting blocks; the three adjusting blocks are rotationally symmetrically distributed about the axis of the diameter-changing module; the drive unit is connected to the positioning shaft and the adjusting blocks respectively; the drive unit is used to drive the three adjusting blocks to move synchronously closer to or further away from the axis of the diameter-changing module;

[0033] A spherical module includes three measuring balls; the spherical module is detachably connected to the variable diameter module; when the spherical module is assembled onto the variable diameter module, the three measuring balls are evenly distributed along the circumference of the variable diameter module, the three measuring balls are spaced apart along the axial direction of the variable diameter module, and the distance from the center of each measuring ball to the axis of the variable diameter module is greater than the diameter of the variable diameter module;

[0034] An electronic measurement module is used to detect the circular diameter determined by the centers of the three measuring spheres.

[0035] Optionally, the sphere module further includes three insert rods; each insert rod is fixedly connected to a measuring ball in a one-to-one correspondence; two measuring balls are located at the ends of the insert rods, and the other measuring ball is located in the middle of the insert rod; one end face of the variable diameter module is provided with slots corresponding to each insert rod; the diameter of the slot is adapted to the diameter of the insert rod; the insert rod and the slot are movably inserted into each other; the axis of the slot is parallel to the axis of the variable diameter module.

[0036] Optionally, the outer peripheral wall of the variable diameter module is provided with a clearance opening that corresponds to and communicates with the slot one by one; the extension direction of the clearance opening is parallel to the axial direction of the variable diameter module; when the ball module is assembled into the variable diameter module, the measuring ball located in the middle of the insertion rod and at least one other measuring ball pass through the clearance opening and are connected to the insertion rod.

[0037] When the lead of the spiral raceway is greater than the threshold, the measuring ball closest to the nut is suspended outside the variable diameter module.

[0038] Optionally, the variable diameter module further includes several pads; the diameter of the pads is adapted to the diameter of the slot; the pads are used to fill the slot to adjust the position of the measuring ball assembled on the variable diameter module.

[0039] Optionally, the diameter of the measuring ball is larger than the diameter of the insertion rod.

[0040] To address the issues of poor versatility of online dedicated inspection tools for nut inner raceways, which can only be adapted to a single product specification, and the problem that offline high-precision inspection results in the loss of positioning references after disassembly, making rework impossible and leading to scrapped workpieces, thus causing material and time losses and hindering production efficiency, this application has the following advantages:

[0041] After pre-grinding the helical raceway of the nut clamped on a grinding machine, the diameter of the ball module is determined. Three measuring balls are then assembled onto the outer circumference of the diameter-changing module, evenly distributed axially and spaced apart along the circumference of the module, ensuring a proper fit between the measuring balls and the nut's helical raceway. By inserting the diameter-changing module into the nut and coaxially with it, the module's diameter is gradually increased while rotating and moving along the helical raceway until the three measuring balls abut against the raceway. The circumferential diameter determined by the centers of the three measuring balls is then measured, completing one measurement. This process allows for inspection without disassembling the nut, maintaining its original clamping position on the grinding machine. This enables online inspection of the pitch circle diameter of the inner raceway in nuts of different specifications, ultimately solving the problem that online inspection tools can only adapt to a single nut specification, and that offline inspection results in the inability to re-clamp and rework nuts, leading to the scrapping of defective products. This reduces waste of raw materials and processing time, improving production efficiency. Attached Figure Description

[0042] Figure 1 A flowchart of the method for detecting the pitch circle diameter of the inner raceway of a nut according to Embodiment 1 is shown;

[0043] Figure 2 An isometric view of the nut inner raceway pitch circle diameter detection device of Embodiment 2 is shown;

[0044] Figure 3 It shows Figure 2 A front view showing the three prongs facing the nut with their ends flush.

[0045] Figure 4 It shows Figure 2 A front view showing the height difference of the three prong end faces facing the nut;

[0046] Figure 5 It shows Figure 2 A front view of the spherical module with the pitch circle diameter of the inner raceway of the nut;

[0047] Figure 6 It shows Figure 2 A front view of the slot and clearance of the device for detecting the pitch circle diameter of the inner raceway of the nut.

[0048] Reference numerals: Positioning shaft 10; Variable diameter module 20; Drive unit 21; Adjusting block 22; Pad block 23; Slot 24; Clearance opening 25; Ball module 30; Measuring ball 31; Insert rod 32; Electronic measuring module 40. Detailed Implementation

[0049] The present disclosure will now be discussed with reference to several exemplary embodiments. It should be understood that these embodiments are discussed only to enable those skilled in the art to better understand and thus implement the present disclosure, and are not intended to imply any limitation on the scope of the disclosure.

[0050] As used herein, the term "comprising" and its variations are to be interpreted as open-ended terms meaning "including but not limited to". The term "based on" is to be interpreted as "at least partially based on". The terms "one embodiment" and "an embodiment" are to be interpreted as "at least one embodiment". The term "another embodiment" is to be interpreted as "at least one other embodiment". The terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "vertical", "horizontal", "lateral", "longitudinal", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments and are not intended to limit the indicated devices, elements, or components to having a specific orientation or being constructed and operated in a specific orientation. Furthermore, some of the above terms may be used to indicate other meanings besides orientations or positional relationships; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application according to the specific circumstances. In addition, the terms "installed", "set up", "equipped with", "connected", and "linked" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. Furthermore, the terms "first," "second," etc., are mainly used to distinguish different devices, elements, or components (the specific types and structures may be the same or different), and are not used to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.

[0051] There are two main limitations in the detection of the pitch circle diameter of the inner raceway of nuts. One is the online detection method, which involves keeping the nut in its clamped state on a grinding machine and using a special detection tool to inspect the helical raceway. However, the structure and measurement parameters of this type of detection tool are custom-designed for the helical raceway characteristics of a single nut specification, and cannot adapt to the detection needs of nuts of different specifications, resulting in extremely poor versatility. The other is the offline detection method, which involves removing the pre-grinding nut from the grinding machine and transferring it to a special precision inspection device such as a coordinate measuring machine or profilometer for inspection. However, after the nut is removed from the grinding machine, its original clamping and positioning reference is completely lost. When the inspection results show that the helical raceway dimensions of the nut do not meet the standard requirements, it is impossible to re-clamp the nut back onto the grinding machine and restore it to its previous precise machining position for rework correction. The unqualified nut can only be scrapped directly. To solve the above problems, this application provides a method and device for detecting the pitch circle diameter of the inner raceway of nuts.

[0052] Example 1:

[0053] In this embodiment, a method for detecting the pitch circle diameter of the inner raceway of a nut is provided, the method comprising steps S10 to S50. For example... Figure 1 As shown, the detection method executes steps S10, S20, S30, S40, and S50 in sequence.

[0054] Step S10 involves pre-grinding the helical raceway of the nut clamped on the grinding machine, and determining the ball diameter of the ball module 30 based on the target size parameters of the helical raceway. This ensures that a measuring ball 31 with the corresponding diameter is matched according to the target size parameters of the nut's helical raceway, guaranteeing the contact accuracy between the measuring ball 31 and the helical raceway, and laying the foundation for accurate measurement of the pitch circle diameter of the inner raceway of the nut. The ball module 30 includes three measuring balls 31, with the ball diameter being the same as the diameter of the measuring ball 31.

[0055] In step S20, the spherical module 30 is assembled onto the outer peripheral wall of the variable diameter module 20. This ensures that the three measuring balls 31 are distributed in a manner consistent with the characteristics of the helical raceway, guaranteeing stable multi-point contact between the measuring balls 31 and the helical raceway, thereby improving the accuracy and reliability of the measurement results.

[0056] When the sphere module 30 is assembled onto the diameter-changing module 20, the three measuring spheres 31 are evenly distributed along the circumference of the diameter-changing module 20, and the three measuring spheres 31 are spaced apart along the axial direction of the diameter-changing module 20.

[0057] In step S30, the reducing module 20 is inserted into the nut and made coaxial with it. This avoids deviation in the contact position between the measuring ball 31 and the helical raceway due to eccentricity, thereby eliminating the influence of eccentricity error on the measurement results.

[0058] In step S40, the diameter of the variable diameter module 20 is gradually increased while rotating and moving it along the extension direction of the helical raceway until the three measuring balls 31 respectively abut against the helical raceway. This allows the measuring balls 31 to smoothly embed into the helical raceway and fit tightly against its surface. Furthermore, since the diameter of the variable diameter module 20 is adjustable, it can adapt to the testing requirements of nuts of different specifications.

[0059] In step S50, when all three measuring balls 31 are in contact with the helical raceway, the circumferential diameter determined by the center of the three measuring balls 31 is obtained, completing one measurement. This allows for accurate calculation of the pitch circle diameter of the inner raceway of the nut, thus enabling testing to be completed without disassembling the nut and maintaining its original clamping state on the grinding machine.

[0060] This embodiment involves inserting the variable diameter module 20 into the nut and coaxializing it with the nut. The diameter of the variable diameter module 20 is gradually increased while simultaneously rotating and moving it along the extension direction of the helical raceway until the three measuring balls 31 abut against the helical raceway. The circumferential diameter determined by the centers of the three measuring balls 31 is then obtained to complete one measurement. This allows for testing while maintaining the nut in its original clamping state on the grinding machine without disassembling it. This enables online testing of the pitch circle diameter of the inner raceway in nuts of different specifications.

[0061] Furthermore, the ball module 30 also includes three insert rods 32. Each insert rod 32 is fixedly connected to a corresponding measuring ball 31. Two measuring balls 31 are located at the ends of the insert rods 32, and the third measuring ball 31 is located in the middle of the insert rod 32. The variable diameter module 20 has slots 24 corresponding to the insert rods 32. The insert rods 32 and slots 24 are movably engaged, and the axis of the slots 24 is parallel to the axis of the variable diameter module 20. It should be understood that the movable engagement of the insert rods 32 and slots 24 facilitates the quick assembly, disassembly, and replacement of the ball module 30. The parallelism of the axis of the slots 24 to the axis of the variable diameter module 20 prevents tilting or offset of the insert rods 32 after installation. Simultaneously, the different positions of the measuring balls 31 on the insert rods 32 can adapt to the thread lead. Furthermore, the design of two measuring balls 31 at the ends of the insert rods 32 and the third measuring ball 31 in the middle of the insert rods 32 allows for the production of only two specifications of insert rods 32 to meet various testing requirements, reducing the types of parts to be produced.

[0062] Step S20 includes steps S21 and S22.

[0063] Step S21: Assemble the measuring ball 31 located in the middle of the insertion rod 32 onto the outer peripheral wall of the variable diameter module 20.

[0064] Step S22: Assemble the two measuring balls 31 located at the ends of the insertion rods 32 onto the outer peripheral wall of the variable diameter module 20.

[0065] With the three measuring balls 31 assembled into the diameter-changing module 20, the measuring ball 31 located in the middle of the insert rod 32 is positioned between the other two measuring balls 31 along the axial direction of the diameter-changing module 20.

[0066] It should be understood that steps S21 and S22 ensure that the three measuring balls 31 are accurately installed on the outer peripheral wall of the variable diameter module 20. After assembly, the axial distribution of the three measuring balls 31 can match the lead characteristics of the nut helical raceway, ensuring that the three measuring balls 31 can simultaneously and accurately abut the corresponding positions of the helical raceway, further improving the accuracy of the measurement results.

[0067] Furthermore, the detection method also includes step S60, and the detection method executes steps S10, S20, S30, S40, S50 and S60 in sequence.

[0068] Step S60: After completing one measurement, accumulate the number of measurements corresponding to the diameter of the sphere. This provides a quantitative basis for subsequent adjustments to the installation and arrangement of the measuring spheres 31, ensuring the traceability and controllability of the usage status of the measuring spheres 31.

[0069] Step S22 includes steps S221 and S222.

[0070] Step S221: When the number of measurements corresponding to the diameter of the ball is less than the first preset number of measurements, the two measuring balls 31 located at the ends of the insertion rod 32 are arranged along the axial spacing of the variable diameter module 20 in the order of the first position.

[0071] In step S222, when the number of measurements corresponding to the diameter of the sphere reaches the first preset number, the two measuring spheres 31 located at the ends of the insertion rod 32 are arranged along the axial spacing of the diameter-changing module 20 according to the second position sequence. The first position sequence is the opposite of the second position sequence.

[0072] It should be understood that since the variable diameter module 20 extends axially into the interior of the nut, this will cause damage to the side of the measuring ball 31 facing the inside of the nut. By limiting the number of times the measuring ball 31 is placed, it is determined whether to change the order of the measuring ball 31 in the axial direction of the variable diameter module 20 and the position of the measuring ball 31 abutting the spiral raceway. This allows multiple positions of the measuring ball 31 to be used for testing, avoiding excessive wear on one side, thereby improving the utilization rate and service life of the measuring ball 31.

[0073] Furthermore, step S21 includes steps S211 and S212.

[0074] Step S211: When the number of measurements corresponding to the diameter of the ball is less than the second preset number of measurements, the measuring ball 31 located in the middle of the insertion rod 32 is assembled to the outer peripheral wall of the variable diameter module 20 with the first orientation.

[0075] Step S212: When the number of measurements corresponding to the diameter of the ball reaches the second preset number, the measuring ball 31 located in the middle of the insertion rod 32 is assembled to the outer peripheral wall of the diameter-changing module 20 in the second orientation.

[0076] It should be understood that by switching the assembly orientation of the measuring ball 31 according to the cumulative number of measurements, the opposite sides of the measuring ball 31 can alternately act as contact sides with the helical raceway, avoiding premature failure due to long-term wear on one side of the measuring ball 31, thereby improving the utilization rate and service life of the measuring ball 31.

[0077] During the insertion of the variable diameter module 20 into the nut, the side of the measuring ball 31 facing the nut is the contact side. The contact sides corresponding to the first orientation and the second orientation are the opposite sides of the measuring ball 31.

[0078] Furthermore, the outer peripheral wall of the variable diameter module 20 is provided with a clearance opening 25 that corresponds to and communicates with the slot 24. The clearance opening 25 can prevent the measuring ball 31 from becoming a cantilever structure, so that part of the circumference of the measuring ball 31 abuts against the variable diameter module 20, thereby improving the service life and structural strength of the measuring ball 31.

[0079] When the ball module 30 is assembled into the variable diameter module 20, the measuring ball 31 located in the middle of the insert rod 32 and at least one other measuring ball 31 pass through the clearance opening 25 and connect to the insert rod 32. This ensures the reliability of the connection between the measuring ball 31 and the insert rod 32, while also allowing the measuring ball 31 to protrude from the outer peripheral wall of the variable diameter module 20 to contact the helical raceway.

[0080] When the lead of the helical raceway is greater than the threshold, the measuring ball 31 closest to the nut extends outward from the variable diameter module 20. This balances the adaptation of helical raceways with different leads and the control of the overall volume of the variable diameter module 20, avoiding structural waste caused by excessive axial length of the variable diameter module 20 in the case of small leads, and ensuring structural stability.

[0081] The first preset number of times is less than the second preset number of times. This is because the measuring ball 31, which is suspended outside the variable diameter module 20, will not only experience wear but also deform due to the force on the cantilever, thus requiring more frequent switching of the installation sequence. The measuring ball 31 located in the middle of the insertion rod 32, however, is never in a suspended state, resulting in better stress conditions. Therefore, the corresponding number of switching times can be set higher. After switching the installation sequence, the axial distribution of the three measuring balls 31 can still adapt to the lead of the helical raceway, ensuring that the measurement accuracy is not affected.

[0082] Furthermore, step S20 also includes step S23.

[0083] In step S23, the number of pads 23 in the two target slots 24 is adjusted according to the lead of the spiral raceway. The position of the measuring ball 31 located in the middle of the insert rod 32 is kept constant, so that the distance between two adjacent measuring balls 31 in the axial direction of the variable diameter module 20 is 1 / 3 of the lead. The target slot 24 is the slot 24 where the insert rod 32 with the measuring ball 31 at its end is located, and the pads 23 are clamped between the bottom wall of the slot 24 and the insert rod 32.

[0084] It should be understood that the pad 23, clamped between the bottom wall of the slot 24 and the insert rod 32, allows for precise adjustment of the axial position of the insert rod 32 within the slot 24 by increasing or decreasing the number of pads 23, thereby changing the axial installation position of the end measuring ball 31. By keeping the position of the measuring ball 31 located in the middle of the insert rod 32 constant, the distance between two adjacent measuring balls 31 can be adjusted by only adjusting the number of pads 23 in the two target slots 24. Compared to adjusting the axial position of three measuring balls 31 simultaneously, this reduces the number of points that need adjustment from three to two, thus reducing the cumulative error caused by multiple adjustments. Furthermore, maintaining a consistent number of pads 23 in both target slots 24 simplifies the operation of adjusting the distance between the measuring balls 31 according to the helical raceway lead, avoids human error caused by different numbers of pads 23 required for different slots 24, reduces the risk of errors from manual operation, ensures the accuracy of the distance between adjacent measuring balls 31, and ensures that all three measuring balls 31 can simultaneously and accurately abut the corresponding positions on the helical raceway.

[0085] It is worth noting that when batch testing nuts of the same specification, when the number of measurements corresponding to the diameter of the sphere reaches the first preset number, such as... Figure 3 As shown, if the end faces of the three insertion rods 32 facing the nut are flush, the switching of the measuring ball 31 contact side can be completed simply by changing the installation direction of the ball module 30 as a whole.

[0086] like Figure 4As shown, if there is an axial height difference between the end faces of the three inserts facing the nut, in addition to changing the installation direction of the ball module 30 as a whole, it is also necessary to change the circumferential installation position of each insert 32 on the variable diameter module to ensure that the axial distribution of the measuring ball 31 is still compatible with the lead of the helical raceway.

[0087] Example 2:

[0088] In this embodiment, a device for detecting the pitch circle diameter of the inner raceway of a nut is provided, which is applied to the method for detecting the pitch circle diameter of the inner raceway of a nut, such as... Figure 2 , Figure 3 , Figure 5 , Figure 6 As shown, the detection device includes a positioning shaft 10, a diameter changing module 20, a ball module 30, and an electronic measurement module 40.

[0089] The positioning shaft 10 serves as a reference component of the detection device, providing a stable installation reference for the diameter-changing module 20 and ensuring the coaxiality of the diameter-changing module 20 and the nut.

[0090] The diameter-changing module 20 is coaxially arranged with the positioning shaft 10. The diameter-changing module 20 includes a drive unit 21 and three adjusting blocks 22. The three adjusting blocks 22 are rotationally symmetrically distributed about the axis of the diameter-changing module 20. The drive unit 21 is connected to both the positioning shaft 10 and the adjusting blocks 22, and is used to drive the three adjusting blocks 22 to move synchronously closer to or further away from the axis of the diameter-changing module 20. It should be understood that the structure of the diameter-changing module 20, where the drive unit 21 drives the three rotationally symmetrically distributed adjusting blocks 22 to move synchronously radially, enables continuous and precise adjustment of the diameter of the diameter-changing module 20, thereby adapting to the internal raceway inspection requirements of nuts of different specifications. Simultaneously, the synchronous movement of the three adjusting blocks 22 ensures that the central axis of the device remains unchanged during the diameter-changing process, avoiding the introduction of eccentricity errors.

[0091] The sphere module 30 includes three measuring balls 31. The sphere module 30 is detachably connected to the diameter-changing module 20, facilitating quick replacement of the measuring balls 31 with the corresponding diameter based on the target size parameters of the nut's helical raceway, further enhancing the device's versatility. When the sphere module 30 is assembled onto the diameter-changing module 20, the three measuring balls 31 are evenly distributed along the circumference of the diameter-changing module 20 and spaced apart along the axial direction of the diameter-changing module 20. This allows them to match the helical characteristics of the helical raceway, forming multi-point stable contact and ensuring the reliability of the measurement results. The distance from the center of each measuring ball 31 to the axis of the diameter-changing module 20 is greater than the diameter of the diameter-changing module 20, ensuring that the measuring balls 31 protrude beyond the outer peripheral wall of the diameter-changing module 20 and effectively contact the helical raceway, preventing interference between the diameter-changing module 20 and the inner hole of the nut.

[0092] The electronic measurement module 40 is used to detect the circular diameter determined by the centers of the three measuring spheres 31. This enables the automatic acquisition and calculation of the circular diameter determined by the centers of the three measuring spheres 31, achieving automated acquisition of detection data and improving detection efficiency and data accuracy.

[0093] Furthermore, the sphere module 30 also includes three insertion rods 32. The one-to-one fixed connection between the insertion rods 32 and the measuring balls 31 ensures the installation position accuracy and connection reliability of the measuring balls 31. The diameter of the slot 24 matches the diameter of the insertion rods 32, preventing radial wobble after insertion and ensuring the radial position stability of the measuring balls 31. Two measuring balls 31 are located at the ends of the insertion rods 32, and the third measuring ball 31 is located in the middle of the insertion rods 32. One end face of the variable diameter module 20 is provided with slots 24 corresponding to the insertion rods 32. The diameter of the slots 24 matches the diameter of the insertion rods 32, and the movable insertion of the insertion rods 32 and slots 24 facilitates the quick disassembly and replacement of the sphere module 30, improving the ease of operation of the testing device. The axis of the slots 24 is parallel to the axis of the variable diameter module 20, ensuring that the insertion rods 32 extend accurately along the axial direction after installation, so that the axial position of the measuring balls 31 meets the design requirements. At the same time, by applying a resisting force through the feed motion along the extension direction of the spiral raceway during the detection process, the pad 23 and the insertion rod 32, and the insertion rod 32 and the bottom wall of the slot 24 can be tightly fitted, eliminating the fit gap and further improving the positional accuracy of the measuring ball 31 and the accuracy of the measurement results.

[0094] Furthermore, the outer peripheral wall of the variable diameter module 20 is provided with clearance openings 25 that correspond one-to-one with the slots 24. The extension direction of the clearance openings 25 is parallel to the axial direction of the variable diameter module 20, which can provide sufficient space for the axial movement of the insertion rod 32, and facilitate the adjustment of the axial position of the measuring ball 31 according to the lead of the helical raceway. When the ball module 30 is assembled into the variable diameter module 20, the measuring ball 31 located in the middle of the insertion rod 32 and at least one other measuring ball 31 pass through the clearance openings 25 and connect with the insertion rod 32, which allows part of the circumference of the measuring ball 31 to abut against the variable diameter module 20, preventing the measuring ball 31 from becoming a completely cantilever structure, and improving the structural strength and service life of the measuring ball 31.

[0095] When the lead of the helical raceway is greater than the threshold, the measuring ball 31 closest to the nut extends outward from the variable diameter module 20. This allows for the adaptation of helical raceways with different leads while controlling the overall axial volume of the variable diameter module 20, avoiding structural waste caused by excessively long axial dimensions of the variable diameter module 20 under small lead conditions.

[0096] It is worth noting that when adjusting the axial position of the measuring ball 31 located at the end of the insertion rod 32, the number of pads 23 corresponding to the two end insertion rods 32 needs to be adjusted simultaneously. However, the position of the measuring ball 31 located in the middle of the insertion rod 32 is constant and does not require frequent adjustment. The assembly orientation is switched only after a preset number of times, simplifying the adjustment operation of the testing device. At the same time, since the middle measuring ball 31 is never in a suspended state, its stress conditions are better than those of the end measuring balls 31, which may be in a suspended state. Therefore, the number of times the corresponding assembly orientation is switched can be set less, further improving the ease of use of the testing device.

[0097] Furthermore, the variable diameter module 20 also includes several pads 23. The diameter of the pads 23 is adapted to the diameter of the slots 24, ensuring that the pads 23 do not wobble after being inserted into the slots 24, and ensuring a tight fit between the insert rod 32 and the pads 23, and between the pads 23 and the bottom wall of the slots 24, maintaining the stable position of the measuring ball 31 after adjustment. The pads 23 are used to insert into the slots 24 to adjust the position of the measuring ball 31 assembled on the variable diameter module 20. By increasing or decreasing the number of pads 23 inserted into the slots 24, the axial insertion depth of the insert rod 32 in the slots 24 can be precisely adjusted, thereby changing the axial position of the measuring ball 31 assembled on the variable diameter module 20, thus adapting to the detection requirements of the inner raceway of nuts with different lead specifications and improving the versatility of the detection device.

[0098] It is worth noting that the axial feed force of the variable diameter module 20 can be used to make the pad 23 abut against the insertion rod 32, thus preventing axial movement.

[0099] Furthermore, the diameter of the measuring ball 31 is larger than the diameter of the insertion rod 32. This allows for a smaller diameter of the insertion rod 32, which in turn reduces the diameter of the pad 23 that matches the diameter of the slot 24. The reduced diameter of the pad 23 improves the surface smoothness and machining accuracy. When two to three standard pads 23 are inserted into the slot 24, the smaller surface area of ​​the pads reduces the cumulative error caused by the stacking of multiple pads 23, thus ensuring the accuracy of the axial position adjustment of the measuring ball 31 and improving the precision of the test results.

[0100] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes can be made in form and detail without departing from the scope of this disclosure.

Claims

1. A method for detecting the pitch circle diameter of the inner raceway of a nut, characterized in that, The detection method includes: Pre-grinding is completed on the helical raceway of the nut clamped on the grinding machine. The diameter of the ball module is determined according to the target size parameters of the helical raceway. The ball module includes three measuring balls. The diameter of the ball is the diameter of the measuring ball. The spherical module is assembled onto the outer peripheral wall of the variable diameter module; wherein, with the spherical module assembled onto the variable diameter module, the three measuring balls are evenly distributed along the circumferential direction of the variable diameter module, and the three measuring balls are spaced apart along the axial direction of the variable diameter module; The diameter-changing module is inserted into the interior of the nut, and the diameter-changing module is coaxial with the nut. The diameter of the variable diameter module is gradually increased while the variable diameter module is rotated and moved along the extension direction of the spiral raceway until the three measuring balls respectively abut against the spiral raceway. When all three measuring balls abut against the spiral raceway, the circumferential diameter determined by the centers of the three measuring balls is obtained, thus completing one measurement.

2. The method for detecting the pitch circle diameter of the inner raceway of a nut according to claim 1, characterized in that, The sphere module also includes three insert rods; each insert rod is fixedly connected to a measuring ball in a one-to-one correspondence; two measuring balls are located at the ends of the insert rods, and the other measuring ball is located in the middle of the insert rod; the variable diameter module has slots that correspond to the insert rods; the insert rods are movably inserted into the slots; the axis of the slots is parallel to the axis of the variable diameter module. The process of assembling the spherical module onto the outer peripheral wall of the variable diameter module includes: The measuring ball located in the middle of the insertion rod is assembled to the outer peripheral wall of the variable diameter module; The two measuring balls located at the ends of the insert rods are assembled to the outer peripheral wall of the variable diameter module; With the three measuring balls assembled into the diameter-changing module, the measuring ball located in the middle of the insert rod is positioned between the other two measuring balls along the axial direction of the diameter-changing module.

3. The method for detecting the pitch circle diameter of the inner raceway of a nut according to claim 2, characterized in that, The detection method further includes: Once a measurement is completed, the number of measurements corresponding to the diameter of the sphere is accumulated. The step of assembling the two measuring balls located at the ends of the insert rods to the outer peripheral wall of the variable diameter module includes: When the number of measurements corresponding to the diameter of the ball is less than the first preset number, the two measuring balls located at the ends of the insert rod are arranged in a first position order along the axial spacing of the variable diameter module. When the number of measurements corresponding to the diameter of the ball reaches the first preset number, the two measuring balls located at the ends of the insert rod are arranged along the axial spacing of the variable diameter module in a second position order; the first position order is the opposite of the second position order.

4. The method for detecting the pitch circle diameter of the inner raceway of a nut according to claim 3, characterized in that, The step of assembling the measuring ball located in the middle of the insertion rod to the outer peripheral wall of the variable diameter module includes: When the number of measurements corresponding to the diameter of the ball is less than the second preset number, the measuring ball located in the middle of the insertion rod is assembled to the outer peripheral wall of the variable diameter module with the first orientation. When the number of measurements corresponding to the diameter of the ball reaches the second preset number, the measuring ball located in the middle of the insertion rod is assembled to the outer peripheral wall of the variable diameter module in the second orientation. During the process of the variable diameter module extending into the nut, the side of the measuring ball facing the nut is the abutting side; the abutting sides corresponding to the first orientation and the second orientation are the opposite sides of the measuring ball.

5. The method for detecting the pitch circle diameter of the inner raceway of a nut according to claim 4, characterized in that, The outer peripheral wall of the variable diameter module is provided with clearance openings that correspond one-to-one with the slots; when the ball module is assembled into the variable diameter module, the measuring ball located in the middle of the insertion rod and at least one other measuring ball pass through the clearance openings and connect to the insertion rod. When the lead of the helical raceway is greater than the threshold, the measuring ball closest to the nut is suspended outside the variable diameter module; The first preset number of times is less than the second preset number of times.

6. The method for detecting the pitch circle diameter of the inner raceway of a nut according to claim 2, characterized in that, The process of assembling the sphere module onto the outer peripheral wall of the variable diameter module further includes: The number of pads in the two target slots is adjusted according to the lead of the spiral raceway, and the position of the measuring ball located in the middle of the insert is kept constant, so that the distance between two adjacent measuring balls in the axial direction of the variable diameter module is 1 / 3 of the lead; wherein, the target slot is the slot where the insert with the measuring ball at the end is located; the pads are held between the bottom wall of the slot and the insert.

7. A device for detecting the pitch circle diameter of the inner raceway of a nut, applied to the method for detecting the pitch circle diameter of the inner raceway of a nut according to any one of claims 1-6; characterized in that, The detection device includes: Positioning axis; A diameter-changing module is coaxially arranged with the positioning shaft; the diameter-changing module includes a drive unit and three adjusting blocks; the three adjusting blocks are rotationally symmetrically distributed about the axis of the diameter-changing module; the drive unit is connected to the positioning shaft and the adjusting blocks respectively; the drive unit is used to drive the three adjusting blocks to move synchronously closer to or further away from the axis of the diameter-changing module; A spherical module includes three measuring balls; the spherical module is detachably connected to the variable diameter module; when the spherical module is assembled onto the variable diameter module, the three measuring balls are evenly distributed along the circumference of the variable diameter module, the three measuring balls are spaced apart along the axial direction of the variable diameter module, and the distance from the center of each measuring ball to the axis of the variable diameter module is greater than the diameter of the variable diameter module; An electronic measurement module is used to detect the circular diameter determined by the centers of the three measuring spheres.

8. The device for detecting the pitch circle diameter of the inner raceway of a nut according to claim 7, characterized in that, The sphere module also includes three insert rods; each insert rod is fixedly connected to a measuring ball in a one-to-one correspondence; two measuring balls are located at the ends of the insert rods, and the other measuring ball is located in the middle of the insert rod; one end face of the variable diameter module is provided with slots corresponding to each insert rod; the diameter of the slot is adapted to the diameter of the insert rod; the insert rod and the slot are movably inserted into each other; the axis of the slot is parallel to the axis of the variable diameter module.

9. The device for detecting the pitch circle diameter of the inner raceway of a nut according to claim 8, characterized in that, The outer peripheral wall of the variable diameter module is provided with clearance openings that correspond one-to-one with the slots; the extension direction of the clearance openings is parallel to the axial direction of the variable diameter module; when the ball module is assembled into the variable diameter module, the measuring ball located in the middle of the insertion rod and at least one other measuring ball pass through the clearance openings and are connected to the insertion rod. When the lead of the spiral raceway is greater than the threshold, the measuring ball closest to the nut is suspended outside the variable diameter module.

10. A device for detecting the pitch circle diameter of the inner raceway of a nut according to claim 8, characterized in that, The variable diameter module also includes several pads; the diameter of the pads is adapted to the diameter of the slot; the pads are used to fill the slot to adjust the position of the measuring ball assembled on the variable diameter module.

11. The device for detecting the pitch circle diameter of the inner raceway of a nut according to claim 8, characterized in that, The diameter of the measuring ball is larger than the diameter of the insertion rod.

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