A method for testing the stiffness and clearance of a steering column based on a whole vehicle

Abstract

A kind of test method based on the stiffness and gap of steering column of whole vehicle is provided, which comprises: in the state of whole vehicle, the output end of steering column is fixedly connected with the steering housing by using constraint device;The first corner value when the steering wheel reaches the first preset torque in clockwise direction is obtained, and the second corner value when the steering wheel reaches the second preset torque in counterclockwise direction is obtained;With the first corner value and the second corner value as boundary, the steering wheel is driven to reciprocate;According to the torque value and the corner value collected in real time during reciprocation, the first relationship curve of torque value and corner value is generated;Based on the first relationship curve, the stiffness value and the gap value of steering column are calculated;By fixing the output end of steering column in the state of whole vehicle, the isolation test condition is created, so that the stiffness and gap of steering column total cost itself are accurately measured in real vehicle environment, and the problems of inconvenient operation and impure data of traditional method are solved.

Description

Technical Field

[0001] This invention relates to the field of automotive parameter testing technology, specifically to a method for testing the stiffness and clearance of the steering column of a whole vehicle. Background Technology

[0002] The stiffness and clearance of the steering column assembly are key parameters that directly affect the steering feel, response accuracy, and driving quality of a vehicle. In order to optimize and objectively evaluate the overall handling performance of a vehicle, there is an urgent need for a test method that can accurately measure the overall stiffness and clearance of the entire steering column assembly (including the steering wheel, column, spline, telescopic mechanism, and all other coupled components) as reflected from the steering wheel input port in a real vehicle assembly state.

[0003] Currently, common testing methods in the industry primarily rely on dedicated laboratory benches. These methods typically isolate the steering column or related components from the vehicle and perform individual stiffness, holding force, or durability tests on the bench. However, such methods have the following drawbacks: (1) The test environment is detached from the actual vehicle's installation angle, constraints and coupling relationship between components. The measured parameters are only at the component level and cannot truly reflect its actual mechanical performance in the whole vehicle system. (2) If you try to measure the torque applied to the steering wheel directly on the whole vehicle, the output end of the steering column is mechanically connected to downstream components such as the steering gear and transmission rod. The input torque will drive the entire steering system to move, which will inevitably mix the resistance, deformation and clearance of the downstream components in the measurement results. It is impossible to accurately separate and quantify the characteristics of the steering column itself. Summary of the Invention

[0004] This application provides a method for testing the stiffness and clearance of the steering column based on a complete vehicle, which solves the technical problem that the existing test scheme cannot be used in the assembled state of the complete vehicle and the direct testing in the vehicle environment leads to inaccurate stiffness and clearance data.

[0005] This application provides a method for testing the stiffness and clearance of a steering column based on a complete vehicle, comprising: In the vehicle state, the output end of the steering column is fixedly connected to the steering gear housing using a restraint device; The system obtains a first angle value when the steering wheel reaches a first preset torque in the clockwise direction, and a second angle value when it reaches a second preset torque in the counterclockwise direction; and drives the steering wheel to reciprocate by using the first angle value and the second angle value as boundaries. Based on the torque and angle values ​​collected in real time during the reciprocating rotation, a first relationship curve between torque and angle values ​​is generated; based on the first relationship curve, the stiffness and clearance values ​​of the steering column are calculated.

[0006] In one embodiment, a constraint device is used to fix the output end of the steering column to the steering gear housing, which includes the following steps: Remove the original connection between the output end of the steering column and the input shaft of the steering gear; One end of the double-ended screw is fixedly connected to the output end of the steering column; Align one end of the two connecting plates and fix them to the end of the double-ended screw away from the output end of the steering column. The other ends of the two connecting plates extend and point to the two predetermined installation positions of the steering gear housing. At two predetermined installation locations, a fixed bracket is fixedly connected to the steering gear housing; the ends of the two connecting plates furthest from the aligned ends are fixedly connected to the corresponding fixed brackets.

[0007] In one embodiment, the first preset torque is equal to the second preset torque.

[0008] In one implementation, a first relationship curve is generated with the rotation angle value as the horizontal axis and the torque value as the vertical axis.

[0009] In one implementation, the stiffness value of the steering column is calculated based on a first relationship curve, which includes the following steps: In the first relationship curve, the segment where the torque value and the rotation angle value change in a linear proportional relationship is identified and extracted as the linear response segment for calculating stiffness; The stiffness value of the steering column is calculated based on the slope of the linear response section.

[0010] In one implementation, the stiffness value of the steering column (1) is calculated based on the slope of the linear response segment, which includes the following steps: Within the linear response range, the ratio of the change in torque to the change in angle is calculated during the outward journey of the steering wheel from the first angle value to the second angle value, and this ratio is used as the slope of the outward journey curve. Simultaneously, the ratio of the change in torque to the change in angle during the return stroke of the steering wheel from the second turning angle value to the first turning angle value is calculated and used as the slope of the return curve. Calculate the average of the slopes of the outgoing curve and the return curve, and use the average value as the stiffness value of the steering column.

[0011] In one implementation, two intersection points of the first relationship curve and the horizontal axis are obtained; based on the two intersection points, the clearance value of the steering column is calculated.

[0012] In one implementation, the clearance value of the steering column is calculated based on a first relationship curve, which includes the following steps: Determine the steering wheel angle value corresponding to each of the two intersection points of the first relationship curve and the horizontal axis; Calculate the difference in steering wheel angle values ​​corresponding to the two intersection points. The absolute value of the difference is the clearance value of the steering column.

[0013] In one implementation, before acquiring the steering wheel angle value, the power steering function of the test vehicle is turned off, and the steering wheel is ensured to be unlocked.

[0014] In one implementation, a regulation strategy is also included, comprising the following steps: Anomaly detection is performed on the real-time collected torque and angle values, and abnormal data points that exceed the preset range are removed; The calculated gap value is compared with the preset gap threshold range. If the gap value is not within the preset gap threshold range, the connection status of the constraint device is checked, and the device is rotated again to obtain the torque and angle values ​​again.

[0015] The beneficial effects of the technical solutions provided in this application include: A method for testing the stiffness and clearance of the steering column based on a complete vehicle assembly is proposed. This method involves fixing the output end of the steering column to the steering gear housing using a constraint device while the vehicle is in its complete assembly state. This creates a test boundary condition within the actual vehicle assembly environment. This operation not only preserves the real-vehicle coupling relationship of all components such as the steering wheel, column, and spline, but also cuts off the path for torque transmission from the steering column to the steering gear and rigidly locks its output end, thus isolating the measurement from downstream steering mechanisms. This ensures that all torque and steering angle input from the steering wheel are completely confined within the steering column assembly, used only to overcome its own elastic deformation and internal clearance. Therefore, this method solves the problem that traditional bench testing is detached from the actual vehicle state, while direct testing on the complete vehicle results in impure data due to system coupling. It achieves accurate and pure measurement of the stiffness and clearance of the steering column assembly itself under complete vehicle assembly conditions.

[0016] Using a preset torque value as the trigger boundary, reciprocating rotation within the corresponding angle range effectively excites and records the mechanical response of the steering column assembly under pure torsional conditions. Determining the angle boundary by reaching the preset torque value ensures that the test covers the load range of the column's operation while avoiding overload. Reciprocating rotation captures the hysteresis characteristics during loading and unloading. The slope of the linear segment of the first relationship curve directly reflects the rate of change of torque and angle, i.e., stiffness. The difference in the intercept of the first relationship curve on the zero torque axis represents the free travel angle required to overcome all internal mechanical play during forward and reverse rotation, i.e., clearance. Therefore, by applying standardized excitation under isolated boundary conditions and directly calculating the stiffness and clearance values ​​from the system's constitutive response curve, the technical problem of inaccurate stiffness and clearance data obtained due to the inability of existing test schemes to be applied in the assembled vehicle state and for direct testing in the vehicle environment is solved. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic flowchart illustrating the method for testing the stiffness and clearance of the steering column based on a whole vehicle, as provided in an embodiment of this application; Figure 2 This is a first schematic diagram of a test scenario provided in an embodiment of this application; Figure 3 This is a schematic diagram of the constraint device provided in the embodiments of this application; Figure 4 This is a second schematic diagram of a test scenario provided in an embodiment of this application; Figure 5 A third schematic diagram of a test scenario provided in an embodiment of this application; Figure 6 A schematic diagram of the first relationship curve provided for an embodiment of this application.

[0019] In the diagram: 1. Steering column; 2. Steering gear; 3. Restraint device; 31. Double-ended screw; 32. Connecting plate; 33. Fixed bracket; 34. Connecting bolt; 35. Matching nut. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0021] To make the technical problem that this application aims to solve clearer, the causes of the technical problem will be analyzed in detail below: The reason why existing technical solutions cannot accurately measure the stiffness and clearance of the steering column 1 in the assembled state of the vehicle lies fundamentally in two interrelated structural technical defects: Current mainstream methods rely on removing the steering column 1 from the vehicle and testing it on a dedicated test bench. This testing method artificially alters the installation boundary conditions of the steering column 1 (such as installation angle and constraint points) and its connection relationship with surrounding components such as the steering wheel and steering gear input splines. Therefore, the measured parameters are only the performance parameters of the steering column 1 component under an idealized laboratory environment, rather than the overall mechanical performance of the steering column 1 assembly in a real vehicle assembly coupling state. Key factors affecting the feel in actual driving, such as the fit clearance between the steering wheel and the column splines and the friction of the column telescopic sleeve, are either excluded or cannot be realistically simulated in this type of test, resulting in a lack of direct and effective correlation between the test results and the driver's actual steering feel.

[0022] If one attempts to measure the force applied directly to the steering wheel on the entire vehicle in pursuit of realism, a more challenging problem arises: the steering system is a continuous force transmission chain. When the steering wheel is turned, the applied torque simultaneously overcomes the deformation and play of the steering column 1 itself, as well as drives the downstream steering gear 2, steering tie rods, and even the tires. Without any system modifications, the "torque-angle" data measured at the steering wheel is actually a "mixed signal" of the superimposed responses of all components in the entire steering system. Noise from friction within the steering gear 2, transmission efficiency, and the interaction forces between the wheels and the ground is inevitably introduced, thus obscuring the truly important, purely "steering column 1 characteristics" that need to be measured. Therefore, while the data obtained from this "direct vehicle testing" includes the actual vehicle conditions, it loses accuracy and specificity due to the inability to isolate the interference from downstream components, making it unsuitable for quantitatively evaluating the performance of the steering column 1 itself.

[0023] refer to Figures 1 to 5 ,in Figure 1This is a flowchart illustrating a method for testing the stiffness and clearance of a steering column based on a whole vehicle, as provided in an embodiment of this application. The method includes: S100. In the vehicle state, the output end of the steering column 1 is fixedly connected to the housing of the steering gear 2 using the restraint device 3. S200: Obtain the first angle value when the steering wheel reaches the first preset torque in the clockwise direction, and the second angle value when it reaches the second preset torque in the counterclockwise direction; drive the steering wheel to reciprocate by using the first angle value and the second angle value as boundaries; S300. Based on the torque and angle values ​​collected in real time during the reciprocating rotation, generate the first relationship curve between the torque and angle values; based on the first relationship curve, calculate the stiffness and clearance values ​​of the steering column 1.

[0024] This method, designed to fix the output end of the steering column 1 to the steering gear 2 housing using constraint device 3 in a vehicle-like state, constructs a test boundary condition within a real vehicle assembly environment. This operation not only preserves the actual vehicle coupling relationship of all components such as the steering wheel, column, and spline, but more importantly, it cuts off the torque transmission path from the steering column 1 to the steering gear 2 and rigidly locks its output end, thus isolating the downstream steering gear 2 from interference with the measurement. This ensures that all torque and steering angle input from the steering wheel are completely confined within the steering column 1 assembly, used only to overcome its own elastic deformation and internal clearance. Therefore, this method solves the problem of traditional bench testing being detached from the actual vehicle state, while direct testing on the vehicle results in impure data due to system coupling. It achieves accurate and pure measurement of the stiffness and clearance of the steering column 1 assembly itself in a vehicle-like state.

[0025] Using a preset torque value as the trigger boundary, reciprocating rotation within the corresponding angle range effectively excites and records the mechanical response of the steering column 1 assembly under pure torsional conditions. Determining the angle boundary by reaching the preset torque value ensures that the test covers the load range of the column's operation while avoiding overload. Reciprocating rotation captures the hysteresis characteristics during loading and unloading. The slope of the linear segment of the first relationship curve directly reflects the rate of change of torque and angle, i.e., stiffness. The difference in the intercept of the first relationship curve on the zero torque axis represents the free travel angle required to overcome all internal mechanical play during the forward to reverse rotation process, i.e., clearance. Therefore, by applying standardized excitation under isolated boundary conditions and directly calculating the stiffness and clearance values ​​from the system's constitutive response curve, the technical problem of inaccurate stiffness and clearance data obtained due to the inability of existing test schemes to be applied in the assembled vehicle state and direct testing in the vehicle environment is solved.

[0026] Furthermore, in one embodiment, the output end of the steering column 1 is fixedly connected to the housing of the steering gear 2 using the constraint device 3, which includes the following steps: Remove the original connecting piece between the output end of steering column 1 and the input shaft of steering gear 2; One end of the double-ended screw 31 is fixedly connected to the output end of the steering column 1; Align one end of the two connecting plates 32 and fix them to the end of the double-ended screw 31 away from the output end of the steering column 1. The other ends of the two connecting plates 32 extend and point to the two predetermined installation positions of the steering gear 2 housing. At two predetermined installation positions, a fixed bracket 33 is fixedly connected to the housing of the steering gear 2; the ends of the two connecting plates 32 away from the alignment are fixedly connected to the corresponding fixed brackets 33.

[0027] In this embodiment, the specific steps are as follows: Remove the clamping nut 35 at the spline connecting the lower universal joint of the steering column 1 and the steering gear 2, and insert the double-ended screw 31 into the bolt hole of the universal joint; Tighten the double-ended screw 31 using the matching nut 35 or the internal thread of the universal joint. The tightening torque should be the same as that required for the removed spline clamping bolt 34. This step replaces the original spline clamp bolt with the double-ended screw 31 used for this fixing fixture. Remove the two adjacent clamping bolts on the upper cover of the steering gear 2, align the lower horizontal surfaces of the two fixing brackets 33 with the mounting surfaces of the original clamping bolts on the upper cover of the steering gear 2, and reinstall the clamping bolts, aligning them with the upper horizontal surfaces of the mounting brackets 33 to press the fixing brackets 33 firmly. During installation, adjust the vertical surfaces of the two fixing brackets 33 to be parallel to each other; Align the round hole ends of the two connecting plates 32 and stack them together, then fit them onto the other end of the double-ended screw 31; the long hole ends of the two connecting plates 32 are respectively attached to the two fixed brackets 33, and the long holes are aligned with the connecting holes of the fixed brackets 33. By using the top nuts, the two connecting plates 32 are pressed tightly together at the round hole ends; Slightly turn the steering wheel to make the vertical surfaces of the two connecting plates 32 and the two fixed brackets 33 fit together, and lock the connecting plates 32 and the fixed brackets 33 together by connecting bolts 34 and matching nuts 45; Tighten all nuts of the restraint device 3 again to complete the fixing of the steering column 1; Since both connecting plates 32 and both fixed brackets 33 are installed and fixed with elongated ends facing round holes, the fixed brackets 33 can be universally adapted to steering gear 2 housings with different hole spacings. Since the two fixed brackets 33 can be fixed by any two adjacent steering gear 2 top cover clamping bolts, the fixed brackets 33 can be installed at any two adjacent steering gear 2 top cover bolt points according to the actual vehicle installation direction of the clamping bolts of the steering column 1, and the steering degree of freedom of the steering column 1 can be fixed.

[0028] Furthermore, in one embodiment, the first preset torque is equal to the second preset torque.

[0029] In this embodiment, by ensuring that the absolute values ​​of the first preset torque (30 Nm) and the second preset torque (-30 Nm) are equal, the symmetry of the test excitation is ensured. This solves the problem that testing under asymmetrical loads may lead to an imbalance in the mechanical response of the steering column assembly in both the forward and reverse rotation directions. This makes the step angle interval (first and second angle values) symmetrical about the steering wheel centerline, resulting in a symmetrical loading and unloading path for the generated angle-torque relationship curve. The symmetrical curve makes it easier to accurately identify and extract the linear response segment, thus calculating a more representative average stiffness. Simultaneously, the two intersections of the curve with the zero-torque axis more accurately reflect the total clearance of the steering column assembly in both directions, avoiding measurement errors caused by insufficient unidirectional test range.

[0030] Furthermore, in one embodiment, the first relationship curve is generated with the rotation angle value as the horizontal axis and the torque value as the vertical axis.

[0031] Furthermore, in one embodiment, the stiffness value of the steering column 1 is calculated based on the first relationship curve, which includes the following steps: In the first relationship curve, the segment where the torque value and the rotation angle value change in a linear proportional relationship is identified and extracted as the linear response segment for calculating stiffness; The stiffness value of steering column 1 is calculated based on the slope of the linear response section.

[0032] Furthermore, in one embodiment, the stiffness value of the steering column 1 is calculated based on the slope of the linear response section, which includes the following steps: Within the linear response range, the ratio of the change in torque to the change in angle is calculated during the outward journey of the steering wheel from the first angle value to the second angle value, and this ratio is used as the slope of the outward journey curve. Simultaneously, the ratio of the change in torque to the change in angle during the return stroke of the steering wheel from the second turning angle value to the first turning angle value is calculated and used as the slope of the return curve. Calculate the average of the outgoing curve slope and the return curve slope, and use the average value as the stiffness value of the steering column 1.

[0033] In this embodiment, a standard curve generation rule was established (rotation angle as the abscissa and torque as the ordinate), providing a unified and unambiguous data foundation for subsequent analysis. Specifically, the rule was to identify and extract linear response segments from the generated curves for calculation. This crucially solves the problem that directly using the overall slope due to nonlinear regions (such as gap segments and friction saturation segments) in the measured curves would lead to severe distortion of stiffness values, ensuring that the data used in the calculations truly reflects the elastic deformation nature of the tubing material and structure. The slopes of the outward and return curves were calculated separately and averaged, eliminating the unidirectional measurement error caused by mechanical hysteresis effects such as internal friction of the steering tubing 1. This results in a more representative and stable average stiffness value, thereby improving the accuracy of the measurement results. Overall, this progressive calculation method extracts the original, interference-laden test data into key parameters that accurately characterize the elastic performance of the steering tubing 1 itself.

[0034] Furthermore, in one embodiment, two intersection points of the first relationship curve and the horizontal axis are obtained; based on the two intersection points, the clearance value of the steering column 1 is calculated.

[0035] Furthermore, in one embodiment, the steering wheel angle value corresponding to each of the two intersection points of the first relationship curve and the horizontal axis is determined; Calculate the difference in steering wheel angle values ​​corresponding to the two intersection points. The absolute value of the difference is the clearance value of steering column 1.

[0036] In this embodiment, the intersection of the curve and the zero-torque axis (horizontal axis) is used to characterize the critical state where the steering input torque is fully used to overcome internal play and has not yet caused elastic deformation of the steering column. Two intersection points are used as the calculation benchmark, and the clearance value is obtained by calculating the absolute value of the difference in the angles between the two intersection points. The difference in the intersection points directly corresponds to the total free travel angle required to overcome all internal play during the forward and reverse steering process. The calculation process is based on measured data, without introducing subjective judgment or complex models, avoiding misjudging other nonlinear deformations (such as friction) as clearance. This ensures the purity, accuracy, and good repeatability of the clearance measurement results, providing key and reliable data indicators for evaluating and optimizing steering feel.

[0037] Furthermore, in one embodiment, before obtaining the steering wheel angle value, the power steering function of the test vehicle is turned off, and the steering wheel is ensured to be in an unlocked state.

[0038] In this embodiment, two common interferences are addressed: disabling the power steering function eliminates the additional auxiliary torque applied to the steering wheel by the electric or hydraulic power steering system, preventing this external torque from contaminating the measurement signal and ensuring that the collected torque-angle data purely reflects the mechanical characteristics of the steering column 1 assembly; ensuring the steering wheel is unlocked avoids the problem of the steering wheel being unable to turn due to mechanical lock-up, thus ensuring the feasibility of the test. Simple and necessary preprocessing steps eliminate key interferences introduced by systems not under test, ensuring the consistency of test conditions and the accuracy of data acquisition, laying a solid foundation for obtaining realistic and repeatable stiffness and clearance calculation results.

[0039] Furthermore, in one embodiment, the system further includes a regulation strategy comprising the following steps: Anomaly detection is performed on the real-time collected torque and angle values, and abnormal data points that exceed the preset range are removed; The calculated gap value is compared with the preset gap threshold range. If the gap value is not within the preset gap threshold range, the connection status of the constraint device 3 is checked, and the device is rotated again to obtain the torque value and angle value again.

[0040] In this embodiment, two risk points in the testing process are addressed: real-time removal of outlier data points ensures the cleanliness of the original data used to generate the relationship curve from the data source, avoiding critical interference from outliers to the final calculation results; and comparing the calculated gap value with a preset threshold and triggering a retest objectively identifies measurement failures caused by systemic installation defects such as unreliable fixture connections, and promptly prompts for retesting. This improves the robustness of the vehicle testing method in practical applications and reduces the excessive reliance on operator experience during the testing process.

[0041] To better understand this solution, a specific practical application of the method will be provided below: After connecting the restraint device 3 as described above, turn off the vehicle's power steering. If the vehicle has a steering wheel lock, it needs to be adjusted to the steering wheel unlocked state. Next, the steering input device (steering robot, or force-measuring steering wheel) is installed. The force-measuring steering wheel is the input device for this system. It is coaxially and fixedly connected to the steering wheel of the vehicle under test, and can measure the steering wheel angle and steering torque input by the driver. The steering robot is the input device for this testing system. It is coaxially and fixedly connected to the steering wheel of the vehicle under test, and can directly input the steering wheel angle and test the steering torque. Both the force-measuring steering wheel and the steering robot can be used as the input device for this testing system. Users can flexibly choose either the force-measuring steering wheel or the steering robot as the input device based on available hardware resources. Using the steering input device, input the steering wheel angle clockwise until the measured torque reaches 30 Nm, and record the steering wheel angle θ1 at this time; After reaching θ1, turn the steering wheel counterclockwise until the steering torque reaches -30Nm, and record the steering wheel angle θ2 at this time; Using a rotation input device (steering robot, or steering wheel), rotate evenly and slowly from θ2 to θ1, and then back to θ2. Repeat this cycle twice and record the first angle-torque relationship curve for this process; Plot the first relationship curve with the steering wheel angle as the x-axis and the torque as the y-axis, and extract the linear region of the first relationship curve and the intersection point θ between the curve and the x-axis (steering wheel angle). 01 and θ 02 ; In the linear region, the slopes K1 and K2 of the outgoing and return curves are calculated respectively. The average value of K1 and K2 is then taken to obtain the stiffness value K of the steering column 1. Take the intersection point θ of the first relationship curve and the x-axis 01 and θ 02 By calculating the difference between the two intersection points, the clearance Δ of the steering column 1 assembly can be obtained.

[0042] The beneficial effects of this invention include: A method for testing the stiffness and clearance of the steering column based on a complete vehicle assembly is proposed. This method involves disconnecting the transmission connection between the output end of the steering column 1 and the input shaft of the steering gear 2 in a complete vehicle configuration, and then using a constraint device 3 to fix the output end of the steering column 1 to the housing of the steering gear 2. This creates a test boundary condition within a real vehicle assembly environment. This operation not only preserves the actual vehicle coupling relationship of all components such as the steering wheel, column, and spline, but more importantly, it cuts off the path for torque transmission from the steering column 1 to the steering gear 2 and rigidly locks its output end, thus isolating the downstream steering gear 2 from interference with the measurement. This ensures that all torque and steering angle input from the steering wheel are completely confined within the steering column 1 assembly, used only to overcome its own elastic deformation and internal clearance. Therefore, this method solves the problem of traditional bench testing being detached from the actual vehicle configuration, while direct testing on the complete vehicle results in impure data due to system coupling. It achieves accurate and pure measurement of the stiffness and clearance of the steering column 1 assembly itself in a complete vehicle assembly configuration.

[0043] Using a preset torque value as the trigger boundary, reciprocating rotation within the corresponding angle range effectively excites and records the mechanical response of the steering column 1 assembly under pure torsional conditions. Determining the angle boundary by reaching the preset torque value ensures that the test covers the load range of the column's operation while avoiding overload. Reciprocating rotation captures the hysteresis characteristics during loading and unloading. The slope of the linear segment of the first relationship curve directly reflects the rate of change of torque and angle, i.e., stiffness. The difference in the intercept of the first relationship curve on the zero torque axis represents the free travel angle required to overcome all internal mechanical play during the forward to reverse rotation process, i.e., clearance. Therefore, by applying standardized excitation under isolated boundary conditions and directly calculating the stiffness and clearance values ​​from the system's constitutive response curve, the technical problem of inaccurate stiffness and clearance data obtained due to the inability of existing test schemes to be applied in the assembled vehicle state and direct testing in the vehicle environment is solved.

[0044] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0045] It should be noted that in this application, relational terms such as "first" and "second" are used merely 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. Furthermore, 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. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0046] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for testing the stiffness and clearance of a steering column based on a complete vehicle, characterized in that, It includes: In the vehicle state, the output end of the steering column (1) is fixedly connected to the housing of the steering gear (2) by the restraint device (3); The system obtains a first angle value when the steering wheel reaches a first preset torque in the clockwise direction and a second angle value when it reaches a second preset torque in the counterclockwise direction; and drives the steering wheel to reciprocate by using the first angle value and the second angle value as boundaries. Based on the torque and angle values ​​collected in real time during the reciprocating rotation, a first relationship curve between torque and angle values ​​is generated. Based on the first relationship curve, the stiffness and clearance values ​​of the steering column (1) are calculated.

2. The method for testing the stiffness and clearance of the steering column based on the whole vehicle as described in claim 1, characterized in that, The process of fixing the output end of the steering column (1) to the housing of the steering gear (2) using a constraint device (3) includes the following steps: Remove the original connecting parts between the output end of the steering column (1) and the input shaft of the steering gear (2); One end of the double-ended screw (31) is fixedly connected to the output end of the steering column (1); Align one end of the two connecting plates (32) and fix them to one end of the double-ended screw (31) away from the output end of the steering column (1). The other ends of the two connecting plates (32) extend and point to two predetermined installation positions of the steering gear (2) housing. At the two predetermined installation positions, a fixed bracket (33) is fixedly connected to the housing of the steering gear (2); the ends of the two connecting plates (32) away from the alignment are fixedly connected to the corresponding fixed brackets (33).

3. The method for testing the stiffness and clearance of the steering column based on the whole vehicle as described in claim 1, characterized in that, The first preset torque is equal to the second preset torque.

4. The method for testing the stiffness and clearance of the steering column based on the whole vehicle as described in claim 3, characterized in that, The first relationship curve is generated by setting the rotation angle value as the horizontal axis and the torque value as the vertical axis.

5. The method for testing the stiffness and clearance of the steering column based on the whole vehicle as described in claim 4, characterized in that, Based on the first relationship curve, the stiffness value of the steering column (1) is calculated, which includes the following steps: In the first relationship curve, the segment where the torque value and the rotation angle value change in a linear proportional relationship is identified and extracted as the linear response segment for calculating stiffness; The stiffness value of the steering column (1) is calculated based on the slope of the linear response section.

6. The method for testing the stiffness and clearance of the steering column based on the whole vehicle as described in claim 5, characterized in that, Based on the slope of the linear response section, the stiffness value of the steering column (1) is calculated, which includes the following steps: Within the linear response range, the ratio of the change in torque to the change in angle is calculated during the outward journey of the steering wheel from the first angle value to the second angle value, and is used as the slope of the outward journey curve. Simultaneously, the ratio of the change in torque to the change in angle during the return stroke of the steering wheel from the second turning angle value to the first turning angle value is calculated and used as the slope of the return curve. Calculate the average of the slope of the outgoing curve and the slope of the return curve, and use the average value as the stiffness value of the steering column (1).

7. The method for testing the stiffness and clearance of the steering column based on the whole vehicle as described in claim 4, characterized in that, Obtain the two intersection points of the first relationship curve and the horizontal axis; calculate the clearance value of the steering column (1) based on the two intersection points.

8. The method for testing the stiffness and clearance of the steering column based on the whole vehicle as described in claim 7, characterized in that, Based on the first relationship curve, the clearance value of the steering column (1) is calculated, which includes the following steps: Determine the steering wheel angle value corresponding to each of the two intersection points of the first relationship curve and the horizontal axis; Calculate the difference between the steering wheel angle values ​​corresponding to the two intersection points, and the absolute value of the difference is the clearance value of the steering column (1).

9. The method for testing the stiffness and clearance of the steering column based on the whole vehicle as described in claim 1, characterized in that, Before obtaining the steering wheel angle value, the test vehicle's power steering function is turned off, and the steering wheel is ensured to be unlocked.

10. The method for testing the stiffness and clearance of the steering column based on the whole vehicle as described in claim 1, characterized in that, It also includes a regulation strategy, which comprises the following steps: Anomaly detection is performed on the real-time collected torque and angle values, and abnormal data points that exceed the preset range are removed; The calculated gap value is compared with the preset gap threshold range. If the gap value is not within the preset gap threshold range, the connection status of the constraint device (3) is checked and rotated again to obtain the torque value and angle value again.

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