Test bench and test method for Rattle abnormal sound test of steering column

Abstract

The invention relates to the field of abnormal sound testing, discloses a test bed and a test method for Rattle abnormal sound testing of a steering column, and aims at solving the industry blank that a steering engine assembly needs to be assembled, linear excitation is adopted, and the steering column cannot be independently and accurately tested in the existing test. And the driving seat which can slide front, back, left and right and can adjust the inclination angle is matched, so that independent installation and accurate positioning of the steering column single bodies are realized, and butt joint can be completed without depending on a steering machine. The driving part output shaft directly transmits instantaneous torque impact, the road bumping working condition is accurately simulated, traditional linear excitation is replaced, the blank of industry special tests is filled up, the test pertinence and authenticity are improved, meanwhile, steering columns of different specifications are adapted, and the universality is high.

Description

Technical Field

[0001] This invention relates to the field of abnormal noise testing, and specifically to a test bench and test method for testing Rattle abnormal noise in steering column. Background Technology

[0002] As automotive NVH (noise, vibration, and harshness) performance becomes one of the core concerns for users, abnormal noises in the steering system (especially rattling noises from collisions) have become a key factor affecting the driving experience. Among them, column-EPS (electric power steering) systems have a more significant impact on the user's perception because the motor is integrated at the top of the steering column and close to the driver, resulting in a short and direct transmission path for abnormal noises. The accurate detection and control of rattling noises in these systems has become a key technical challenge for the industry.

[0003] Currently, when testing Rattle noise in steering systems, the upper steering column and the lower steering gear must be assembled into a complete assembly before testing can be carried out. However, the excitation source for this integrated test is applied to the steering tie rod, i.e., the tire mounting position. The excitation form is a linear input to simulate the linear impact of road bumps on the tire. However, the steering column is subjected to the instantaneous torque impact transmitted by the road bumps during vehicle operation, rather than a linear force. The road bumps are first converted into the rotational impact of the tire, and then transmitted as torque through the steering gear to the column, ultimately triggering collision noises from the internal components of the column. Therefore, in the existing tests, when Rattle noise is found, it is impossible to determine whether the source of the noise is the steering column itself, the steering gear, or a problem with the combination of the two. It is also impossible to test the column as an independent component, which leads to high cost and low efficiency in fault tracing during the R&D stage. Based on this problem, the following improvements are proposed. Summary of the Invention

[0004] The present invention aims to provide a test bench and test method for testing Rattle noise in steering column, so as to solve the problem in the prior art that the overall testing of steering assembly makes it impossible to determine whether the source of Rattle noise is the steering column itself.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a test bench for testing Rattle noise in steering columns, comprising a chassis, a first movable seat slidably disposed on the chassis, a second movable seat slidably disposed on the top of the first movable seat, a column rotatably disposed on the top of the second movable seat, a mounting seat slidably disposed vertically on the column, and a tooling for mounting the steering column rotatably disposed on the mounting seat, the rotation axis of the tooling being perpendicular to the column; the chassis also slidably disposed a drive seat, which can slide back, forth, left, and right on the chassis, the drive seat comprising an adjustment part and a drive part, the drive part being rotatably disposed on the top of the adjustment part, the drive part comprising an output shaft rotatably disposed on the top of the drive part, the output shaft being used to connect with the steering column and drive the steering column to rotate, and the adjustment part being used to adjust the tilt angle and position of the drive part.

[0006] The beneficial effects of this solution are as follows: Through multi-dimensional adjustment of the first moving seat, the second moving seat, the column, and the mounting seat, combined with the steering adjustment of the tooling, the steering column under test can be independently clamped and precisely positioned. The test can be completed without assembling it with the steering gear as a complete assembly. The core problem is solved directly from the test scenario. If Rattle noise is detected, it can be directly identified as a problem with the steering column itself, which greatly reduces the cost and time cost of fault tracing during the R&D stage.

[0007] The forward, backward, left, and right sliding and tilt adjustment functions of the drive unit can adapt to the installation posture requirements of different specifications of steering columns, ensuring precise coaxial connection between the output shaft and the steering column, and avoiding additional interference introduced by assembly deviations. The drive unit directly transmits instantaneous torque impact to the steering column through the output shaft, replicating the real force chain of road bumps - tire rotation impact - steering gear torque transmission during vehicle driving, replacing the linear excitation form of existing tests, and solving the problem of misjudgment of abnormal noise caused by the discrepancy between traditional tests and actual working conditions.

[0008] The coordinated adjustment capability of multiple components and the drive structure design ensure independent testing of the steering column while taking into account the stability of power transmission and the versatility of testing. It adapts to the testing requirements of steering columns of different vehicle models, enhances the applicability and value of the test bench, and provides reliable hardware support for the Rattle noise test of the steering column.

[0009] Preferably, as an improvement, the drive unit further includes a drive housing, a motor installed in the drive housing, and an acoustic package disposed inside the drive housing. The acoustic package is used to reduce noise and vibration during motor operation. The output shaft is rotatably disposed in the drive housing, and the motor output end is coaxially connected to the output shaft via a coupling.

[0010] The beneficial effects are: the acoustic package effectively reduces motor operating noise and vibration, avoids interference with Rattle abnormal noise detection, and the coupling ensures stable transmission between the motor and the output shaft, improving torque transmission accuracy.

[0011] Preferably, as an improvement, it also includes several cross shafts of different specifications, the cross shafts being used for coaxial connection to the bottom end of the steering column, and the other end of the cross shafts being used for coaxial connection with the output shaft.

[0012] The benefits are: different specifications of cross shafts can be adapted to various models of steering columns, compensate for installation angle deviations, broaden the application range of the experimental platform, and reduce adaptation costs.

[0013] Preferably, as an improvement, it also includes a drive input module, which includes a torque sensor, a signal conditioning circuit, a PID controller and a motor driver. The torque sensor is configured in the coupling, the motor driver is set in the drive housing and electrically connected to the motor, the signal conditioning circuit is connected to the torque sensor signal, and the PID controller is electrically connected to the signal conditioning circuit and the motor driver respectively. The torque sensor collects the output torque in real time and feeds it back to the PID controller to form a closed-loop control circuit.

[0014] The beneficial effects are: the closed-loop control module corrects the torque deviation in real time, improves the tracking accuracy of the target torque waveform, and ensures loading stability.

[0015] Preferably, as an improvement, it also includes an inertial simulation unit, which includes several load disks of different masses and several traction ropes. The load disks are coaxially connected to the top of the steering column, and the traction ropes are connected between the load disks and the chassis.

[0016] The beneficial effects are: interchangeable load plates of different masses can simulate the inertia of corresponding vehicle models, the traction rope provides elastic reciprocating load, restoring the real force conditions of the steering system, and improving the authenticity of abnormal noise testing. Preferably, as an improvement, a slide table is fixed in the left and right directions of the chassis, a first movable seat is slidably connected to the slide table, a first lead screw is provided in the left and right directions of the slide table, the first lead screw passes through the first movable seat, the first lead screw is threadedly connected to the first movable seat, and a first motor for driving the first lead screw to rotate is provided on the slide table.

[0017] Preferably, as an improvement, a second lead screw is rotatably mounted on the first movable seat in a back-and-forth direction, and a second motor for driving the second lead screw to rotate is installed on the first movable seat. The second lead screw is threadedly connected to and passes through the second movable seat.

[0018] Preferably, as an improvement, the top of the second movable seat is provided with a worm gear mechanism, the column is set on the worm gear, the worm is used to drive the worm gear to rotate, the outer wall of the column is vertically provided with a third lead screw, the top of the column is installed with a third motor for driving the third lead screw to rotate, the third lead screw is threadedly connected and passes through the mounting seat, the mounting seat is also provided with a worm gear mechanism, and the tooling is set on the mounting seat through the worm gear mechanism.

[0019] Preferably, as an improvement, the upper surface of the chassis is provided with a number of interconnected longitudinal and transverse grooves in the front-to-back and left-to-right directions, respectively. The adjustment part includes a sliding block and a pitching platform slidably connected to the chassis. The top of the sliding block is inclined, and the pitching platform is rotatably disposed at the inclined top of the sliding block. A gear drive mechanism is provided between the sliding block and the pitching platform. The gear drive mechanism is used to adjust the tilt angle of the pitching platform on the sliding block.

[0020] Another object of the present invention is to provide a test method for a test bench for testing Rattle noise in steering columns, comprising the following steps: S0: Sample Installation and Load Configuration: Assemble the steering column and cross shaft to be tested into a test sample and fix it to the column fixture; select an inertial simulation unit of appropriate specifications according to the steering system inertia parameters of the test vehicle model; install the load plate at the steering wheel mounting position of the steering column; the traction rope adopts an elastic rope and spring rope structure, usually two ropes are symmetrically connected on both sides of the load plate; the upper end of the traction rope is connected to the load plate, and the other end is fixed to the chassis; adjust the pretension of the two traction ropes to simulate the elastic reciprocating load of the steering system and ensure that the sample is coaxially connected with the output shaft; S1: Torque setting and closed-loop regulation: Set the target torque waveform according to test requirements and generate standardized torque control commands; S2: Torque closed-loop regulation and high-frequency response optimization: When the motor is started, the torque signal is collected and transmitted in real time through the torque sensor. The deviation value between the torque and the target torque is input to the PID controller. The PID controller is linked with the feedforward compensation algorithm, and the motor driver adjusts the motor output current in real time. The feedforward compensation algorithm outputs the pre-control command in advance according to the sudden change slope of the target torque. The PID controller corrects the residual deviation, improves the system bandwidth, and ensures that the torque sudden change response time is ≤10ms, so as to achieve accurate tracking of the target waveform by the actual torque. S3: Sensor Placement and Synchronization Calibration: Vibration sensors are placed at the cross shaft connection of the steering column, the outside of the drive box, and the steering wheel mounting position, respectively. Microphones are placed around the steering column. The torque sensor, vibration sensor, and microphones are time-synchronized to ensure that the signal timestamp error is ≤1ms. S4: Synchronous signal acquisition and correlation analysis: During the torque loading process, the torque signal, vibration acceleration signal, and sound pressure signal are recorded synchronously, and the acquisition duration is consistent with the duration of the target torque waveform; S5: Abnormal Noise Judgment: If the three conditions of time correlation, intensity correlation and frequency correlation are met at the same time, and the sound pressure level and vibration acceleration reach and exceed the corresponding thresholds, then the steering column under test is judged to have Rattle abnormal noise; otherwise, it is judged to be qualified.

[0021] High-frequency dynamic impact is directly output through closed-loop control of motor torque, which simplifies the structure and eliminates mechanical triggering delay. It can more accurately reflect whether the excitation can cause abnormal vibration and sound in the unit. Through closed-loop feedback between the motor and the high-precision torque sensor, microsecond-level torque fluctuation control is achieved, which accurately reproduces the impact load under actual working conditions. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the steering column installed on the test bench according to an embodiment of the present invention; Figure 2 for Figure 1 A partial structural diagram showing the steering column at point A connecting the tooling and the drive unit. Detailed Implementation

[0023] The following detailed description illustrates the specific implementation method: The reference numerals in the accompanying drawings include: chassis 1, slide table 11, first lead screw 111, first motor 112, first moving seat 2, second lead screw 21, second motor 22, second moving seat 3, column 4, mounting base 41, tooling 411, third lead screw 42, third motor 43, drive seat 5, adjusting part 51, sliding block 511, pitch table 512, drive part 52, drive box 521, motor 5211, acoustic package 5212, output shaft 5213, coupling 5214, torque sensor 5215, cross shaft 6, load plate 7, traction rope 8, steering column 9.

[0024] Example like Figures 1-2 The test bench shown is for testing rattle noise in steering column. It includes a chassis 1. The upper surface of the chassis 1 has several interconnected longitudinal and transverse grooves in the front-to-back and left-to-right directions, respectively. The longitudinal and transverse grooves are evenly spaced. Slides 11 are symmetrically fixed to the front and rear sides of the chassis 1 in the left-to-right direction. T-slots are formed on the upper surface of the slides 11. A first movable seat 2 is slidably connected to the T-slot of the slide in the left-to-right direction. A T-shaped slider is fixed to the bottom of the first movable seat 2 and embedded in the T-slot of the slide 11. A first lead screw 111 is rotatably connected to the slide 11 in the left-to-right direction. The base 2 has a threaded hole through which the first lead screw 111 passes and is threadedly connected. The ends of the slides 11 on both sides are rotatably connected to the connecting lead screw and the connecting box. The end of the connecting lead screw is rotatably connected to the connecting box, and the end of the first lead screw 111 is also rotatably connected to the connecting box. The connecting box is equipped with a first motor 112, which drives the connecting lead screw to rotate. At the same time, in the connecting box, the connecting lead screw and the first lead screw 111 transmit power through bevel gear meshing. Therefore, the first motor 112 drives the first lead screw 111 on both sides to rotate by driving the connecting lead screw to rotate.

[0025] like Figures 1-2As shown, a second movable seat 3 is slidably mounted on the top of the first movable seat 2. The first movable seat 2 and the second movable seat 3 are also slidably connected by a T-shaped groove and a T-shaped slider. A second lead screw 21 is rotatably mounted on the first movable seat 2. A second motor 22 is mounted on the first movable seat 2 to drive the second lead screw 21 to rotate. The output end of the second motor 22 is coaxially connected to the second lead screw 21. The second movable seat 3 also has a threaded hole for the second lead screw 21 to pass through and be threadedly connected. The second motor 22 drives the second movable seat 3 to slide back and forth on the first movable seat 2 by driving the second lead screw 21. A column 4 is rotatably mounted on the top of the second movable seat 3. A worm gear mechanism is mounted on the top of the second movable seat 3. The worm gear is horizontally rotatably connected to the top of the second movable seat 3. A rotating handle is mounted on the end of the worm gear. Rotating the handle can drive the worm gear to rotate. The column 4 is rotatably connected to the top of the worm gear mechanism. The column 4 is coaxially connected to the worm gear. Therefore, rotating the handle can drive the worm gear mechanism. The column 4 rotates, and a mounting plate is fixedly connected to the outer wall of the column 4. A mounting seat 41 is vertically slidably mounted on the mounting plate. The mounting seat 41 and the mounting plate are also slidably connected through a T-slot and a T-block. A third lead screw 42 is vertically rotatably connected to the column 4. A third motor 43 is mounted at the top of the column 4 to drive the third lead screw 42 to rotate. The output end of the third motor 43 is coaxially connected to the third lead screw 42. The mounting seat 41 also has a threaded hole for the third lead screw 42 to pass through and be threadedly connected. The mounting seat 41 is driven to slide vertically on the mounting plate by the third motor 43. The mounting seat 41 is also equipped with a worm gear mechanism. A handle is also provided at the end of the worm. The worm gear is rotatably connected to the surface of the mounting seat 41. The rotation axis of the worm gear is perpendicular to the surface of the mounting seat 41. The worm gear mechanism itself is rotatably connected to a tool 411. The rotation axis of the tool 411 coincides with the rotation axis of the worm gear. The tool 411 is connected to the worm gear. Therefore, the tool 411 can be driven to rotate on the mounting seat 41 by turning the handle.

[0026] like Figures 1-2As shown, the chassis 1 is also slidably equipped with a drive seat 5, which can slide back, forth, left, and right on the chassis 1. The drive seat 5 includes an adjustment part 51 and a drive part 52. The adjustment part 51 includes a sliding block 511 slidably connected to the chassis 1. The bottom end of the sliding block 511 is provided with a slider and is slidably connected by embedding in the longitudinal groove and the transverse groove. The adjustment part 51 also includes a pitch platform 512. The top end of the sliding block 511 is inclined, and the pitch platform 512 is rotatably disposed at the inclined top end of the sliding block 511. A gear drive mechanism is provided between the sliding block 511 and the pitch platform 512. The gear drive mechanism is used to adjust the tilt angle of the pitch platform 512 on the sliding block 511. For example, Chinese invention patent with announcement number CN119435920A discloses a method for large phased array radar. The test pitch turntable and its design method are similar to those in this scheme. The top plate is equivalent to the pitch platform 512 in this scheme, and the bottom plate and column 4 are equivalent to the sliding block 511 in this scheme. The inclined surface at the top of the column 4 is equivalent to the inclined surface at the top of the sliding block 511 in this scheme. A gear drive mechanism is provided between the sliding block 511 and the pitch platform 512. The gear drive mechanism includes an adjustment shaft rotatably connected to the sliding block 511, a handle set on the adjustment shaft, a gear coaxially set on the adjustment shaft, and a sector tooth fixed to the bottom of the pitch platform 512. The sector tooth meshes with the gear. The pitch platform 512 can be driven to adjust the angle by rotating the handle of the adjustment shaft. In addition, the bottom of the sliding block 511 is fixed in position by bolts abutting against the chassis 1.

[0027] like Figures 1-2 As shown, the drive unit 52 includes a drive housing 521, a motor 5211 installed inside the drive housing 521, and an acoustic enclosure 5212 disposed inside the drive housing 521. The acoustic enclosure 5212 is used to reduce the noise and vibration of the motor 5211 during operation. The output shaft 5213 is rotatably mounted on the drive housing 521. The output end of the motor 5211 is coaxially connected to the output shaft 5213. A coupling 5214 is provided between the output shaft 5213 and the output end of the motor 5211. The top outer side of the pitch stage 512 A worm gear structure is also provided, with the rotation axis of the worm gear perpendicular to the surface of the pitch stage 512. A handle is also provided at the end of the worm, and the worm gear is operated to rotate by the handle. One side wall of the drive box 521 is rotatably connected to the housing of the worm gear structure on the pitch stage 512, and the rotation axis of this side wall of the drive box 521 coincides with the rotation axis of the worm gear. The worm gear is connected to this side wall of the drive box 521, so that the drive box 521 can be driven to rotate on the pitch stage 512 by rotating the handle.

[0028] It also includes several cross shafts 6 of different specifications. The cross shafts 6 are used for coaxial connection to the bottom end of the steering column 9, and the other end of the cross shaft 6 is used for coaxial connection with the output shaft 5213. The connection between the cross shaft 6 and the steering column 9 is a detachable spline fit structure. The end of the cross shaft 6 is provided with a spline interface adapted to the steering column, and the two are coaxially fixedly connected through spline engagement. The other end of the cross shaft 6 is detachably connected via a flange. It also includes a drive input module, which includes a torque sensor 5215, a signal conditioning circuit, a PID controller, and a motor driver 5211. The torque sensor 5215 is configured on the coupling 5214, and the motor driver 5211... The actuator is installed in the drive box 521 and electrically connected to the motor 5211. The signal conditioning circuit is connected to the torque sensor 5215. The PID controller is electrically connected to the signal conditioning circuit and the motor 5211 driver respectively. The torque sensor 5215 collects the output torque in real time and feeds it back to the controller to form a closed-loop control loop. It also includes an inertial simulation unit, which includes several load disks 7 of different masses and two traction ropes 8. The load disks 7 are coaxially connected to the top of the steering column 9. The traction ropes 8 adopt the structure of elastic rope and spring rope, usually two ropes are symmetrically connected on both sides of the load disks 7. The upper end of the traction rope 8 is connected to the load disk 7, and the other end is fixed to the chassis 1.

[0029] A test method for a steering column 9Rattle abnormal noise test bench includes the following steps: S0: Sample installation and load configuration: Assemble the steering column 9 and cross shaft 6 to be tested as a test sample and fix it to the tooling 411 on the column 4; Select an inertial simulation unit of appropriate specifications according to the steering system inertia parameters of the test vehicle model; Install the load plate 7 on the steering wheel mounting position of the steering column 9; Adjust the pretension of the two traction ropes 8 to simulate the elastic reciprocating load of the steering system and ensure that the sample and the output shaft 5213 are coaxially connected. S1: Torque setting and closed-loop adjustment: Set the target torque waveform (such as step, pulse or random signal) according to the test requirements. The peak value of step torque is 5-200 N•m and the duration is 0.1-5s; the peak value of pulse torque is 5-200 N•m and the pulse width is 10-1000 ms; the frequency range of random torque is 0.1-100 Hz and the peak value is 5-200 N•m, generating standardized torque control commands. S2: Torque closed-loop regulation and high-frequency response optimization: Start the motor 5211, and the torque signal is collected and transmitted in real time through the torque sensor 5215. The deviation value between the torque and the target torque (set deviation threshold ≤ ±2%) is input to the PID controller. The PID controller is linked with the feedforward compensation algorithm, and the output current of the motor 5211 is adjusted in real time through the motor 5211 driver. The feedforward compensation algorithm outputs the pre-control command in advance according to the sudden change slope of the target torque. The PID controller corrects the residual deviation and increases the system bandwidth to ≥1kHz, ensuring that the torque sudden change response time is ≤10ms, and realizing the accurate tracking of the target waveform by the actual torque. S3: Sensor Arrangement and Synchronization Calibration: Vibration sensors are arranged at the cross shaft 6 connection of the steering column 9, the outside of the drive box 521, and the steering wheel mounting position, respectively. Microphones are arranged around the steering column 9. Time synchronization calibration is performed on the torque sensor 5215, vibration sensors, and microphones to ensure that the signal timestamp error is ≤1ms. S4: Synchronous Signal Acquisition and Correlation Analysis: During torque loading, torque signals, vibration acceleration signals, and sound pressure signals are recorded synchronously. The acquisition duration is consistent with the duration of the target torque waveform. Correlation is analyzed from three dimensions: 1. Time correlation: Determine whether noise and vibration signals are triggered within 0-50ms after a sudden torque change; 2. Strength Correlation: Calculate the Pearson correlation coefficient between the peak torque impact and the sound pressure level and vibration acceleration. A strong correlation is defined as a correlation coefficient ≥ 0.7. 3. Frequency Correlation: Through spectrum analysis, it was confirmed that the overlap between the main frequencies of noise and vibration and the torque impact frequency is ≥80%; S5: Abnormal Noise Judgment: If the three conditions of time correlation, intensity correlation and frequency correlation are met at the same time, and the sound pressure level is ≥45dB(A) or the vibration acceleration is ≥0.5g, then the steering column 9 under test is judged to have Rattle abnormal noise; otherwise, it is judged to be qualified.

[0030] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A test bench for testing Rattle noise in steering columns, characterized in that: Includes a chassis, a first movable seat that slides left and right on the chassis, a second movable seat that slides back and forth on the top of the first movable seat, a column that is rotatably mounted on the top of the second movable seat, a mounting seat that is vertically slidably mounted on the column, and a tooling for mounting a steering column that is rotatably mounted on the mounting seat, with the rotation axis of the tooling perpendicular to the column. The chassis also has a slidably mounted drive seat, which can slide back, forth, left, and right on the chassis. The drive seat includes an adjustment part and a drive part. The drive part is rotatably mounted on the top of the adjustment part. The drive part includes an output shaft rotatably mounted on the top of the adjustment part. The output shaft is used to connect with the steering column and drive the steering column to rotate. The adjustment part is used to adjust the tilt angle and position of the drive part.

2. The test bench according to claim 1, characterized in that: The drive unit also includes a drive housing, a motor installed in the drive housing, and an acoustic package located inside the drive housing. The acoustic package is used to reduce noise and vibration during motor operation. The output shaft is rotatably mounted in the drive housing, and the motor output end is coaxially connected to the output shaft via a coupling.

3. The test bench according to claim 2, characterized in that: It also includes several cross shafts of different specifications. The cross shaft is used for coaxial connection to the bottom end of the steering column, and the other end of the cross shaft is used for coaxial connection with the output shaft.

4. The test bench according to claim 3, characterized in that: It also includes a drive input module, which includes a torque sensor, a signal conditioning circuit, a PID controller and a motor driver. The torque sensor is configured in the coupling, the motor driver is set in the drive box and electrically connected to the motor, the signal conditioning circuit is connected to the torque sensor signal, and the PID controller is electrically connected to the signal conditioning circuit and the motor driver respectively. The torque sensor collects the output torque in real time and feeds it back to the PID controller to form a closed-loop control loop.

5. The test bench according to claim 4, characterized in that: It also includes an inertial simulation unit, which consists of several load disks of different masses and several traction ropes. The load disks are coaxially connected to the top of the steering column, and the traction ropes are connected between the load disks and the chassis.

6. The test bench according to claim 1, characterized in that: A slide table is fixed to the left and right sides of the chassis. A first movable seat is slidably connected to the slide table. A first lead screw is provided on the left and right sides of the slide table. The first lead screw passes through the first movable seat and is threadedly connected to the first movable seat. A first motor for driving the first lead screw to rotate is provided on the slide table.

7. The test bench according to claim 6, characterized in that: A second lead screw is rotatably mounted on the first movable seat in a back-and-forth direction. A second motor for driving the second lead screw to rotate is installed on the first movable seat. The second lead screw is threadedly connected to and passes through the second movable seat.

8. The test bench according to claim 7, characterized in that: The second movable seat is equipped with a worm gear mechanism at its top. The column is mounted on the worm gear, and the worm is used to drive the worm gear to rotate. A third lead screw is vertically mounted on the outer wall of the column. A third motor is installed at the top of the column to drive the third lead screw to rotate. The third lead screw is threadedly connected to and passes through the mounting seat. The mounting seat is also equipped with a worm gear mechanism. The tooling is mounted on the mounting seat through the worm gear mechanism.

9. The test bench according to claim 8, characterized in that: The upper surface of the chassis has several interconnected longitudinal and transverse grooves in the front-to-back and left-to-right directions. The adjustment part includes a sliding block and a pitching platform that are slidably connected to the chassis. The top of the sliding block is inclined, and the pitching platform is rotatably set at the inclined top of the sliding block. A gear drive mechanism is provided between the sliding block and the pitching platform. The gear drive mechanism is used to adjust the tilt angle of the pitching platform on the sliding block.

10. The test method for a steering column Rattle noise test bench according to claim 5, characterized in that: Includes the following steps: S0: Sample Installation and Load Configuration: Assemble the steering column and cross shaft to be tested into a test sample and fix it to the column fixture; select an inertial simulation unit of appropriate specifications according to the steering system inertia parameters of the test vehicle model; install the load plate at the steering wheel mounting position of the steering column; the traction rope adopts an elastic rope and spring rope structure, usually two ropes are symmetrically connected on both sides of the load plate; the upper end of the traction rope is connected to the load plate, and the other end is fixed to the chassis; adjust the pretension of the two traction ropes to simulate the elastic reciprocating load of the steering system and ensure that the sample is coaxially connected with the output shaft; S1: Torque setting and closed-loop regulation: Set the target torque waveform according to test requirements and generate standardized torque control commands; S2: Torque closed-loop regulation and high-frequency response optimization: When the motor is started, the torque signal is collected and transmitted in real time through the torque sensor. The deviation value between the torque and the target torque is input to the PID controller. The PID controller is linked with the feedforward compensation algorithm, and the motor driver adjusts the motor output current in real time. The feedforward compensation algorithm outputs the pre-control command in advance according to the sudden change slope of the target torque. The PID controller corrects the residual deviation, improves the system bandwidth, and ensures that the torque sudden change response time is ≤10ms, so as to achieve accurate tracking of the target waveform by the actual torque. S3: Sensor Placement and Synchronization Calibration: Vibration sensors are placed at the cross shaft connection of the steering column, the outside of the drive box, and the steering wheel mounting position, respectively. Microphones are placed around the steering column. The torque sensor, vibration sensor, and microphones are time-synchronized to ensure that the signal timestamp error is ≤1ms. S4: Synchronous signal acquisition and correlation analysis: During the torque loading process, the torque signal, vibration acceleration signal, and sound pressure signal are recorded synchronously, and the acquisition duration is consistent with the duration of the target torque waveform; S5: Abnormal Noise Judgment: If the three conditions of time correlation, intensity correlation and frequency correlation are met at the same time, and the sound pressure level and vibration acceleration reach and exceed the corresponding thresholds, then the steering column under test is judged to have Rattle abnormal noise; otherwise, it is judged to be qualified.

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