Tightening torque testing device and method for locking nut of gearbox
By designing a torque testing device for the tightening nut of a gearbox, and utilizing the fit between the support shaft and the bearing, as well as a dial indicator assembly, the problem of large theoretical calculation errors in the tightening torque was solved, enabling accurate measurement and rapid detection of the bearing's negative clearance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-03
AI Technical Summary
In existing technologies, the theoretical calculation error of locking torque is large, making it impossible to accurately control the negative clearance of the bearing, which affects the wheel runout suppression effect and makes it difficult to adapt to the bearing requirements of different brands and specifications.
A device for testing the tightening torque of a gearbox locking nut was designed. By combining the clearance fit and interference fit between the support shaft and the bearing with a dial indicator assembly, the displacement of the bearing sleeve can be accurately captured, and the relationship between the axial negative clearance and the tightening torque can be measured.
It enables accurate measurement of tightening torque for bearings of different brands and specifications, avoids theoretical calculation errors, improves production and testing efficiency, has strong applicability, and is easy to operate.
Smart Images
Figure CN121783419A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of gearbox locking nuts, and particularly relates to a device and method for testing the tightening torque of gearbox locking nuts. Background Technology
[0002] During vehicle operation, wheel runout can severely impact driving stability, safety, and ride comfort, and may also accelerate component wear and shorten service life. As a core component of the vehicle's transmission system, the operating condition of the support shaft bearings in the drive gearbox directly affects wheel running accuracy. To effectively reduce wheel runout during vehicle operation, the industry commonly employs a negative clearance structure design for the drive gearbox support shaft bearings. By controlling the amount of negative clearance in the bearings, the operating accuracy of the bearings is ensured, thereby suppressing wheel runout. This has become one of the key technological directions for improving vehicle driving performance.
[0003] In existing technologies, the negative clearance of the support shaft bearing is controlled by the preload of the lock nut, and the magnitude of the preload is determined by the locking torque. Therefore, accurately obtaining the locking torque corresponding to the negative clearance is the core of achieving precise preload. However, the theoretical calculation process of the locking torque is extremely complex, and the differences in the number of balls, fit tolerances, and material properties of bearings from different brands lead to large errors in the theoretical calculation results, making it impossible to provide reliable guidance for actual production and difficult to accurately control the negative clearance of the bearing, thus affecting the wheel runout suppression effect. How to simply, cost-effectively, and accurately measure the locking torque required for different bearings and different negative clearance requirements has become a pressing technical problem in the industry. Therefore, there is an urgent need for a device and method for testing the tightening torque of the gearbox lock nut. Summary of the Invention
[0004] To address some or all of the technical problems existing in the prior art, the present invention provides a device and method for testing the tightening torque of a gearbox locking nut.
[0005] In one aspect of the present invention, a torque testing device for a gearbox locking nut is provided, comprising a working platform, a support shaft vertically disposed at the top of the working platform, and a dial indicator assembly disposed on one side of the support shaft, wherein: The support shaft includes a first shaft segment disposed at the top of the working platform and a second shaft segment integrally connected to the top of the first shaft segment. The outer diameter of the second shaft segment is larger than that of the first shaft segment, and the first shaft segment and the second shaft segment are connected by a stepped surface. The second shaft segment is fitted with a bearing on its outer periphery, and a bearing sleeve is fitted on the outer periphery of the bearing. The inner ring of the bearing and the second shaft segment are in clearance fit, and the outer ring of the bearing and the bearing sleeve are in interference fit. The bottom end of the inner ring of the bearing abuts against the stepped surface. The second shaft segment has a threaded section at its end, and a locking nut is threaded to the outer circumference of the threaded section. The bottom end of the locking nut abuts against the top of the inner ring of the bearing, and the dial indicator assembly is connected to the top of the bearing sleeve.
[0006] Furthermore, in the above-mentioned gearbox locking nut tightening torque testing device, the dial indicator assembly includes a base fixedly connected to the top of the working platform, a column perpendicular to the top of the base, a lever arm vertically connected to the outer periphery of the column, a testing component vertically connected to the lever arm, and the free end of the testing component abutting against the top of the bearing sleeve.
[0007] Furthermore, in the above-mentioned gearbox locking nut tightening torque testing device, a limiting groove is provided in the circumferential direction of the bearing, and a limiting block matching the limiting groove is provided on the inner side of the bearing sleeve, and the limiting block is inserted into the limiting groove.
[0008] In another aspect of the present invention, the method for testing the tightening torque of the gearbox locking nut provided by the present invention includes: Step 1: After assembling the device, make the bottom end of the bearing inner ring fit against the stepped surface, the bottom end of the locking nut fit against the top end of the bearing inner ring, and the dial indicator assembly abut against the top end of the bearing sleeve. At this time, due to gravity, the axial clearance of the bearing is zero. Record the reading of the dial indicator assembly at this time as a1. Step 2: Apply torque M to the locking nut. The locking nut causes the bearing and the bearing sleeve to move downwards. The reading of the dial indicator assembly begins to change and finally stabilizes at a2. Record the reading of the dial indicator assembly at this time as a2. Step 3: Record the difference between a2 and a1 as the axial negative clearance value of the bearing, where M is the tightening torque required for the bearing to achieve the axial negative clearance.
[0009] The gearbox locking nut tightening torque testing device and method of the present invention have the following advantages and positive effects: This invention features a simple structure and convenient assembly / disassembly. By setting a clearance fit between the bearing inner ring and the support shaft, and an interference fit between the bearing outer ring and the bearing sleeve, combined with the precise capture of bearing sleeve displacement by a dial indicator assembly, it can accurately reflect the correspondence between the bearing's axial negative clearance and tightening torque, avoiding errors in theoretical calculations. It is compatible with bearings of different brands and specifications, and can meet the tightening torque measurement needs under different negative clearance requirements. It has good applicability, and the testing method is clear and does not require complex professional operating skills, enabling rapid measurement of tightening torque and effectively improving production testing efficiency. Attached Figure Description
[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for further understanding of the embodiments of the present invention and constitute a part of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 This is a schematic diagram of the gearbox locking nut tightening torque testing device of the present invention.
[0011] Explanation of reference numerals in the attached figures: 1. Working platform; 2. Support shaft; 3. Dial indicator assembly; 31. Base; 32. Column; 33. Lever arm; 34. Test assembly; 4. Bearing; 5. Bearing sleeve; 6. Locking nut. Detailed Implementation
[0012] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0013] This invention provides a device and method for testing the tightening torque of a gearbox lock nut, such as... Figure 1 As shown, the gearbox locking nut tightening torque testing device includes a working platform 1, a support shaft 2 vertically mounted on the top of the working platform 1, and a dial indicator assembly 3 mounted on one side of the support shaft 2. More specifically, the working platform 1 serves as the basic load-bearing component of the entire testing device, providing a stable installation reference for the support shaft 2 and the dial indicator assembly 3, ensuring the positional stability of each component during the test, and avoiding measurement errors caused by foundation shaking. The working platform 1 must have sufficient structural strength to withstand the weight of each component and the applied tightening torque during the test, ensuring the stability of the overall structure. The support shaft 2 provides an assembly carrier for the bearing 4, bearing sleeve 5, and locking nut 6, and achieves preliminary axial positioning of the bearing 4 through its own structure. The dial indicator assembly 3 accurately captures the axial displacement of the bearing sleeve 5, providing data for the calculation of negative clearance. The support shaft 2 includes a first shaft segment set at the top of the working platform 1 and a second shaft segment integrally connected to the top of the first shaft segment. The outer diameter of the second shaft segment is larger than that of the first shaft segment. The first shaft segment and the second shaft segment are connected by a stepped surface. More specifically, the core function of the stepped surface is to provide an axial limiting reference for the inner ring of the bearing 4, so that the bottom end of the inner ring of the bearing 4 can be stably abutted, ensuring the accurate formation of a zero clearance state under subsequent gravity. The second shaft section is fitted with a bearing 4 on its outer circumference, and a bearing sleeve 5 is fitted on the outer circumference of the bearing 4. The inner ring of the bearing 4 and the second shaft section are fitted with a clearance fit. The core function of this fit is to enable the inner ring of the bearing 4 to move synchronously with the axial movement of the locking nut 6, so as to avoid displacement jamming caused by excessive tightness. The outer ring of the bearing 4 and the bearing sleeve 5 are fitted with an interference fit. This fit ensures that the outer ring of the bearing 4 and the bearing sleeve 5 form a stable integral structure, so that the displacement of the outer ring of the bearing 4 can be completely transmitted to the bearing sleeve 5, providing an accurate transmission carrier for the displacement measurement of the dial indicator assembly 3. The bottom end of the inner ring of the bearing 4 abuts against the stepped surface. The second shaft section has a threaded section at its end, and a locking nut 6 is threadedly connected to the outer circumference of the threaded section. The locking nut 6 moves axially through the threaded transmission, thereby applying a preload to the inner ring of the bearing 4. The bottom end of the locking nut 6 abuts against the top end of the inner ring of the bearing 4, and the dial indicator assembly 3 is connected to the top end of the bearing sleeve 5.
[0014] As a specific embodiment, in the gearbox locking nut tightening torque testing device of the present invention, the dial indicator assembly 3 includes a base 31 fixedly connected to the top of the working platform 1, a column 32 perpendicular to the top of the base 31, a lever arm 33 vertically connected to the outer periphery of the column 32, a test assembly 34 vertically connected to the lever arm 33, and the free end of the test assembly 34 abutting against the top of the bearing sleeve 5, which can convert the axial displacement of the bearing sleeve 5 into a readable numerical signal, and realize the accurate recording of the displacement.
[0015] As a specific embodiment, in the gearbox locking nut tightening torque testing device of the present invention, a limiting groove is formed in the circumference of the bearing 4, and a limiting block matching the limiting groove is formed on the inner side of the bearing sleeve 5. The limiting block is inserted into the limiting groove. This structure can realize the circumferential and axial limiting between the bearing 4 and the bearing sleeve 5, prevent relative rotation between the two during the test, ensure that the displacement of the bearing 4 is only generated along the axial direction, and further improve the accuracy of the measurement.
[0016] On the other hand, the gearbox locking nut tightening torque test method of the present invention is implemented using the above-mentioned tightening torque test device, and specifically includes the following steps: Step 1: First, assemble the entire testing device according to the assembly requirements, ensuring that all components are securely connected. Vertically fix the support shaft 2 to the top of the work platform 1. Sequentially install the bearing 4 and bearing sleeve 5 on the outer circumference of the second shaft section of the support shaft 2, ensuring that the bottom end of the inner ring of the bearing 4 is stably against the stepped surface of the support shaft 2, and that the limiting block on the inner side of the bearing sleeve 5 is precisely inserted into the limiting groove of the bearing 4. Then, thread the locking nut 6 to the threaded section of the second shaft section and adjust the position of the locking nut 6 so that its bottom end is against the top end of the inner ring of the bearing 4. Finally, adjust the position of the dial indicator assembly 3 so that the free end of the testing assembly 34 is stably against the top end of the bearing sleeve 5, and ensure that the dial indicator assembly 3 is in normal working condition. After assembling the device, make the bottom end of the inner ring of the bearing 4 against the stepped surface, the bottom end of the locking nut 6 against the top end of the inner ring of the bearing 4, and the dial indicator assembly 3 against the top end of the bearing sleeve 5. At this time, due to gravity, the axial clearance of the bearing 4 is zero. Record the reading of the dial indicator assembly 3 at this time as a1. This reading will serve as the reference value for subsequent displacement measurements. Step 2: Apply torque M to the locking nut 6 using a torque application tool. The locking nut 6 causes the bearing 4 and bearing sleeve 5 to move downwards. More specifically, under the action of threaded transmission, the locking nut 6 moves downwards along the axial direction of the second shaft section, applying a downward preload to the inner ring of the bearing 4. Since the inner ring of the bearing 4 and the second shaft section are clearance fit, the inner ring of the bearing 4 moves downwards synchronously under the preload, thereby pushing the outer ring of the bearing 4 and the bearing sleeve 5, which is interference-fitted with the outer ring, to move downwards synchronously. As the bearing sleeve 5 moves downwards, the test end of the dial indicator assembly 3, which is against its top, moves accordingly. The reading of the dial indicator assembly 3 begins to change and finally stabilizes at a2. Record the reading of the dial indicator assembly 3 at this time as a2. During this process, it is necessary to ensure that the torque is applied smoothly to avoid component displacement deviation caused by instantaneous impact force, while ensuring that the dial indicator assembly 3 is always in normal working condition to ensure the accuracy of the reading. Step 3: Record the difference between a2 and a1 as the axial negative clearance value of bearing 4. M is the tightening torque required for bearing 4 to achieve axial negative clearance. If it is necessary to obtain the tightening torque corresponding to different negative clearance values, repeat steps 2 and 3 above. By adjusting the torque applied to the locking nut 6, record the dial indicator reading a2 under different stable conditions, calculate the corresponding difference, and match the corresponding torque M to obtain the tightening torque data required under different negative clearance requirements.
[0017] In summary, compared with the prior art, the gearbox locking nut tightening torque testing device and method of the present invention have the following advantages and positive effects: This invention features a simple structure and convenient assembly / disassembly. By setting a clearance fit between the inner ring of the bearing 4 and the support shaft 2, and an interference fit between the outer ring of the bearing 4 and the bearing sleeve 5, and with the precise capture of the displacement of the bearing sleeve 5 by the dial indicator assembly 3, it can accurately reflect the correspondence between the axial negative clearance of the bearing 4 and the tightening torque, avoiding errors in theoretical calculations. It is compatible with bearings 4 of different brands and specifications, and can meet the tightening torque measurement requirements under different negative clearance requirements. It has good applicability, and the testing method is clear and does not require professional and complex operating skills. It can achieve rapid measurement of tightening torque and effectively improve production testing efficiency.
[0018] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Meanwhile, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In addition, the terms "front," "rear," "left," "right," "upper," and "lower" in this document refer to the placement states shown in the accompanying drawings.
[0019] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A device for testing the tightening torque of a gearbox locking nut, characterized in that, It includes a working platform, a support shaft vertically mounted on the top of the working platform, and a dial indicator assembly mounted on one side of the support shaft, wherein: The support shaft includes a first shaft segment disposed at the top of the working platform and a second shaft segment integrally connected to the top of the first shaft segment. The outer diameter of the second shaft segment is larger than that of the first shaft segment, and the first shaft segment and the second shaft segment are connected by a stepped surface. The second shaft segment is fitted with a bearing on its outer periphery, and a bearing sleeve is fitted on the outer periphery of the bearing. The inner ring of the bearing and the second shaft segment are in clearance fit, and the outer ring of the bearing and the bearing sleeve are in interference fit. The bottom end of the inner ring of the bearing abuts against the stepped surface. The second shaft segment has a threaded section at its end, and a locking nut is threaded to the outer circumference of the threaded section. The bottom end of the locking nut abuts against the top of the inner ring of the bearing, and the dial indicator assembly is connected to the top of the bearing sleeve.
2. The gearbox locking nut tightening torque testing device according to claim 1, characterized in that, The dial indicator assembly includes a base fixedly connected to the top of the working platform, a column perpendicular to the top of the base, a lever arm vertically connected to the outer periphery of the column, a test component vertically connected to the lever arm, and the free end of the test component abutting against the top of the bearing sleeve.
3. The gearbox locking nut tightening torque testing device according to claim 1, characterized in that, The bearing has a circumferentially oriented locating groove, and the bearing sleeve has an inner locating block that matches the locating groove. The locating block is inserted into the locating groove.
4. A method for testing the tightening torque of a gearbox lock nut, wherein the method is implemented using the tightening torque testing device as described in any one of claims 1 to 3, comprising: Step 1: After assembling the device, make the bottom end of the bearing inner ring fit against the stepped surface, the bottom end of the locking nut fit against the top end of the bearing inner ring, and the dial indicator assembly abut against the top end of the bearing sleeve. At this time, due to gravity, the axial clearance of the bearing is zero. Record the reading of the dial indicator assembly at this time as a1. Step 2: Apply torque M to the locking nut. The locking nut causes the bearing and the bearing sleeve to move downwards. The reading of the dial indicator assembly begins to change and finally stabilizes at a2. Record the reading of the dial indicator assembly at this time as a2. Step 3: Record the difference between a2 and a1 as the axial negative clearance value of the bearing, where M is the tightening torque required for the bearing to achieve the axial negative clearance.