A method for selecting and designing a tightening torque of a passenger car wheel fastener set

Abstract

The present application relates to a kind of passenger car wheel fastener group selection and tightening torque design method, comprising the following steps: fastener group strength check: for the stress condition of wheel fastener group, multiple limit conditions are analyzed by CAE, the stress condition at wheel center is calculated, based on the stress CAE calculation result of step A1, the stress analysis is carried out to wheel fastener group, the stress condition of single wheel fastener is confirmed, the stress condition under multiple limit conditions at single wheel fastener is calculated, the maximum value of shear force demand clamping force and axial force clamping force appeared in multiple limit conditions is selected and accumulated addition, the minimum clamping force of fastener is calculated and checked, and the scheme selection of wheel fastener group is completed; the strength and durability of test verification are carried out.The present application design method clearly defines the selection of passenger car wheel fastener group and the calculation method of tightening torque, test verification method, to meet the development of passenger car wheel fastener group.

Description

Technical Field

[0001] This invention belongs to the field of passenger vehicle technology, specifically relating to a method for selecting and designing tightening torque for passenger vehicle wheel fastener assemblies. Background Technology

[0002] With the continuous progress of society and the economy, passenger vehicles are becoming increasingly sophisticated in their configurations and larger in their overall dimensions, leading to a continuous increase in vehicle weight. Wheels are typically secured to wheel hub bearings with 4, 5, or 8 fasteners, necessitating careful selection of the fasteners used to secure the wheels and calculation of the tightening torque. Currently, detailed design calculation methods exist for individual fasteners; however, when multiple fasteners work together as a fastener group, the complex operating conditions make it difficult to develop a universal calculation method.

[0003] Wheel fastener assemblies experience complex stresses in actual use, bearing the longitudinal forces generated by vehicle acceleration and deceleration, the lateral forces generated during cornering, and the vertical forces generated during bumps. Furthermore, these conditions may occur simultaneously, complicating the calculations for wheel fastener assemblies. Due to tire blowouts or winter tire changes, wheel fastener assemblies often require repeated use, necessitating designs with sufficient safety margins to accommodate such reuse. Current solutions address this by analyzing specific operating conditions, but a definitive design calculation method for wheel fastener assemblies remains lacking. As critical safety components, wheel fastener assemblies require rigorous and reliable selection of solutions and calculation of tightening torques. Summary of the Invention

[0004] The purpose of this invention is to provide a method for selecting and designing the tightening torque of wheel fastener assemblies for passenger vehicles. This method clarifies the selection and tightening torque design of wheel fastener assemblies for passenger vehicles, thereby solving the problem that the increasing weight of passenger vehicles necessitates the re-selection of wheel fastener assemblies and the determination of tightening torque.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for selecting and designing tightening torque for passenger car wheel fastener assemblies includes the following steps:

[0007] A. Fastener assembly strength check

[0008] A1. CAE analysis was performed on various extreme working conditions to calculate the stress at the wheel center for the stress condition of the wheel fastener assembly.

[0009] A2. Perform stress analysis on the wheel fastener assembly based on the CAE calculation results of the stress in step A1.

[0010] A3. Confirm the stress condition of a single wheel fastener and calculate the stress condition of a single wheel fastener under various extreme working conditions.

[0011] A4. Select the maximum values ​​of shear force and axial force clamping force required under various extreme working conditions and sum them up. Perform the minimum clamping force calculation and verification of the fastener to complete the wheel fastener group scheme selection.

[0012] B. Conduct tests to verify the strength and durability.

[0013] Further, in step A1, the operating conditions are 9 types, namely vertical impact, turning, reversing braking, maximum braking, maximum acceleration, lateral impact, forward handbrake, reverse handbrake and curb impact.

[0014] Furthermore, during vertical impact, reverse braking, maximum braking, maximum acceleration, forward handbrake application, and reverse handbrake application, the loading position is the center of both wheels.

[0015] Furthermore, during cornering, lateral impacts, and curb impacts, the loading point is the left wheel center. Further, in step A3, when confirming the stress on individual wheel fasteners, sealing requirements for the wheel fastener assembly do not need to be considered.

[0016] Further, step A3, calculating the stress conditions at a single wheel fastener under various extreme working conditions includes: calculating the shear force required for clamping and the axial force required for clamping of a single wheel.

[0017] Furthermore, the shear force required by the wheel includes both tangential force and torque.

[0018] Furthermore, by equally distributing the load at the wheel center according to the number of fasteners in the fastener group and performing coordinate transformation, the stress conditions at a single wheel fastener under various extreme working conditions can be obtained.

[0019] Furthermore, in step B, the strength and durability are further verified through full-vehicle reinforcement tests on rough roads, regional adaptability, comprehensive durability tests, and road tests in Wuzhishan, Hainan.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This invention provides a method for selecting and designing the tightening torque of wheel fastener assemblies for passenger vehicles. It specifies and clarifies the selection and tightening torque calculation methods, as well as the experimental verification methods, to meet the needs of passenger vehicle wheel fastener assembly development and solve the problem that the increasing weight of passenger vehicles necessitates the re-selection of wheel fastener assemblies and the determination of tightening torque. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 Flowchart of passenger car wheel fastener selection and tightening torque design method. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments:

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0026] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] like Figure 1 As shown, the present invention provides a method for selecting and designing the tightening torque of fastener assemblies for passenger vehicles, including fastener assembly strength verification and test validation.

[0028] Among them, the strength calculation and verification of the fastener group is the key to the design. Through strength verification, the strength selection calculation of the fastener group of passenger car wheels and the tightening torque calculation of the fastener group of passenger car wheels can be realized.

[0029] 1. Fastener assembly strength check:

[0030] If the strength of the wheel fastener assembly is too low, it can lead to thread damage or even fastener breakage, causing vehicle instability and significantly impacting the user's driving experience and safety. Therefore, it is essential to rigorously and reliably determine the strength of the wheel fastener assembly.

[0031] Based on the experience of developing individual fasteners, the fastener calculation and verification mainly considers the minimum clamping force, which is related to the clamping force required by shear force, the clamping force required by sealing, and the clamping force required by axial force. The calculation formula is shown in (1). How to obtain the stress situation of the wheel fastener group under various working conditions and transform the stress situation of the fastener group into the stress situation of the individual fastener is the key to the research of this invention.

[0032] F 最小夹紧力 =max(F 剪切力需求夹紧力 ;F 密封功能需求夹紧力 +F 轴向力需求夹紧力 (1)

[0033] CAE analysis was performed on various extreme operating conditions of the vehicle to calculate the stress at the wheel center, considering the stress on the wheel fastener assembly.

[0034] The stress conditions of the wheel fastener assembly have been determined. The next step is to confirm the stress conditions of individual wheel fasteners. For ordinary fasteners, the minimum clamping force needs to be calculated based on the clamping force required for shear force, sealing, and axial force. Sealing requirements do not need to be considered for the wheel fastener assembly.

[0035] The shear force required for clamping of a wheel mainly consists of the tangential force required for clamping and the torque required for clamping. When calculating the clamping force of a single wheel fastener, the tangential force required for clamping, the torque required for clamping, and the axial force required for clamping are mainly considered.

[0036] By dividing the load at the wheel center equally according to the number of fasteners in the fastener group and performing coordinate transformation, the stress conditions of a single wheel fastener under various extreme working conditions can be obtained.

[0037] Since multiple extreme working conditions cannot coexist, the maximum values ​​of the clamping force required by tangential force, the clamping force required by torque, and the clamping force required by axial force will appear in various different working conditions. However, in order to ensure the strength of the wheel fasteners, and in combination with the vehicle test results, the maximum values ​​of the clamping force required by tangential force, the clamping force required by torque, and the clamping force required by axial force in various extreme working conditions are selected and summed up to calculate and verify the minimum clamping force of the fasteners. The specific calculation formula is shown in (2). Subsequently, the tightening torque is further calculated according to the requirements of VDI2230.

[0038] F 最小夹紧力 =F 极限工况切向力需求夹紧力最大值 +F 极限工况扭矩需求夹紧力最大值 +F 极限工况轴向力需求夹紧力最大值 (2)

[0039] After the wheel fastener assembly scheme is selected, it is necessary to conduct tests to verify its strength and durability. FAW uses complete vehicle reinforcement for rough roads, regional adaptability, comprehensive durability, and Hainan Wuzhishan road tests to further verify the strength and durability.

[0040] Example 1

[0041] A method for selecting and designing tightening torque for passenger car wheel fastener assemblies includes the following steps:

[0042] 1. Fastener assembly strength check

[0043] CAE analysis was performed on nine extreme conditions of wheel fastener assembly, including vertical impact, turning, reverse braking, maximum braking, maximum acceleration, lateral impact, forward handbrake, reverse handbrake, and curb impact, to calculate the stress at the wheel center.

[0044] During vertical impact, reverse braking, maximum braking, maximum acceleration, forward handbrake application, and reverse handbrake application, the loading position is the center of both wheels. During turning, lateral impact, and curb impact, the loading position is the center of the left wheel.

[0045] Table 1 shows the CAE analysis results of the force calculation at the wheel center. FAW conducted a force analysis on the wheel fastener group based on the CAE calculation results of the wheel center force under nine extreme working conditions.

[0046] Table 1. Extreme working condition force analysis at the rear suspension center of a certain SUV model.

[0047]

[0048] The stress analysis of the wheel fastener group is performed based on the stress CAE calculation results; the stress condition of a single wheel fastener is confirmed, and the stress condition of a single wheel fastener under various extreme working conditions is calculated.

[0049] The maximum values ​​of shear force and axial force clamping force required in 9 extreme working conditions are selected and summed to calculate and verify the minimum clamping force of the fasteners, thus completing the selection of wheel fastener group scheme.

[0050] When verifying the stress condition of a single wheel fastener, sealing requirements do not need to be considered for the wheel fastener assembly. Calculating the stress condition of a single wheel fastener under various extreme conditions includes: calculating the shear force clamping force and axial force clamping force required for the single wheel. The shear force clamping force required for the wheel includes the tangential force clamping force and the torque clamping force.

[0051] Since the table calculated by CAE shows the force at the wheel center under 9 extreme working conditions, the load at the wheel center is evenly distributed according to the number of fasteners in the fastener group, and coordinate transformation is performed to obtain the force at the fastener of a single wheel under 9 extreme working conditions.

[0052] 2. The strength and durability were further verified through full-vehicle reinforcement tests on rough roads, regional adaptability, comprehensive durability tests, and road tests in Wuzhishan, Hainan.

[0053] FAW has adopted this method of selecting and tightening torque design for passenger vehicle wheel fasteners to complete the development of multiple models. It has also solved the problem of wheel bolt breakage in a certain SUV model in Wuzhishan, Hainan. After the production of a certain SUV prototype, a large number of tests were conducted, and no wheel bolt breakage problem occurred. This shows that this method of selecting and tightening torque design for passenger vehicle wheel fasteners meets the design and development requirements.

[0054] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for selecting and designing tightening torque for passenger car wheel fastener assemblies, characterized in that, Includes the following steps: A. Fastener assembly strength check A1. CAE analysis was performed on various extreme working conditions to calculate the stress at the wheel center for the stress condition of the wheel fastener assembly. A2. Perform a stress analysis on the wheel fastener assembly based on the CAE calculation results of step A1. A3. Confirm the stress condition of a single wheel fastener and calculate the stress condition of a single wheel fastener under various extreme working conditions. A4. Select the maximum values ​​of shear force and axial force clamping force required under various extreme working conditions and sum them up. Perform the minimum clamping force calculation and verification of the fastener to complete the wheel fastener group scheme selection. B. Conduct tests to verify the strength and durability.

2. The method for selecting and designing tightening torque of a passenger car wheel fastener assembly according to claim 1, characterized in that: Step A1, the operating conditions are 9 types, namely vertical impact, turning, reversing braking, maximum braking, maximum acceleration, lateral impact, forward handbrake, reverse handbrake and curb impact.

3. The method for selecting and designing tightening torque of a passenger car wheel fastener assembly according to claim 2, characterized in that: When experiencing vertical impact, reversing braking, maximum braking, maximum acceleration, pulling the handbrake while moving forward, or pulling the handbrake while reversing, the loading position is at the center of both wheels.

4. The method for selecting and designing tightening torque of a passenger vehicle wheel fastener assembly according to claim 2, characterized in that: When turning, experiencing lateral impacts, or encountering curb impacts, the load is applied to the left wheel center.

5. The method for selecting and designing tightening torque of a passenger vehicle wheel fastener assembly according to claim 1, characterized in that: In step A3, when confirming the stress condition of a single wheel fastener, the sealing requirements of the wheel fastener group do not need to be considered.

6. The method for selecting and designing tightening torque of a passenger car wheel fastener assembly according to claim 5, characterized in that: Step A3, calculating the stress conditions at a single wheel fastener under various extreme working conditions, includes: calculating the shear force, clamping force, and axial force clamping force required for a single wheel.

7. The method for selecting and designing tightening torque of a passenger vehicle wheel fastener assembly according to claim 6, characterized in that: The shear force required for wheel clamping includes tangential force clamping force and torque clamping force.

8. The method for selecting and designing tightening torque of a passenger vehicle wheel fastener assembly according to claim 7, characterized in that: By dividing the load at the wheel center equally according to the number of fasteners in the fastener group and performing coordinate transformation, the stress conditions of a single wheel fastener under various extreme working conditions can be obtained.

9. The method for selecting and designing tightening torque of a passenger vehicle wheel fastener assembly according to claim 1, characterized in that: Step B involves conducting full-vehicle reinforcement tests on rough roads, regional adaptability, comprehensive durability, and road tests in Wuzhishan, Hainan, to further verify the strength and durability.

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