Suspension Bushing Test Method and Test Tooling

Abstract

The present invention relates to the technical field of auto parts for automobiles, and particularly relates to a method for testing a suspension bushing and a testing tooling. Among them, the method for testing a suspension bushing includes: obtaining the static reaction force F received by the suspension bushing according to different working conditions of the automobile n mj ; based on the static reaction force F n mj , a two-way dynamic stiffness testing device applies bidirectional loads in a first direction, a second direction, and a third direction to the suspension bushing, and the first direction, the second direction, and the third direction are perpendicular to each other in pairs; obtaining the mechanical performance data of the suspension bushing under each of the bidirectional loads; calculating the dynamic stiffness parameter k of the suspension bushing based on the mechanical performance data n dmj . In the technical solution of the present invention, it aims to obtain the dynamic stiffness parameter of the engine mount bushing, so as to provide reference data for the NVH performance design of the whole vehicle.

Description

Technical Field

[0001] The present invention relates to the technical field of auto parts for automobiles, and particularly relates to a method for testing a suspension bushing and a testing tooling. Background Art

[0002] NVH performance, namely Noise, Vibration, and Harshness performance, is an important indicator for measuring the comfort and quality of automobiles. It covers all the noises, vibrations generated during the operation of the vehicle and the discomfort caused to the driver and passengers. Good NVH performance can provide a more comfortable and quiet riding environment for the passengers, while reducing the fatigue damage of vehicle components and improving the overall service life of the vehicle.

[0003] The dynamic stiffness parameter of the mounting bushing plays a crucial role in NVH performance. Dynamic stiffness refers to the stiffness characteristics of the bushing under dynamic load, which directly affects the transmission and attenuation of engine vibration and road surface impact by the mounting system. A suitable dynamic stiffness parameter can effectively isolate the vibration between the engine and the vehicle body, reduce the interior noise of the vehicle, and improve the riding comfort. On the contrary, if the dynamic stiffness parameter does not match, it may lead to the aggravation of NVH problems and affect the overall performance of the vehicle.

[0004] In the related art, there are some deficiencies in the traditional dynamic stiffness testing methods. First of all, these methods often adopt unidirectional preloading and cannot comprehensively reflect the multi-directional stress state of the bushing in actual work. Secondly, the correspondence between the preloading magnitude and the actual vehicle conditions is not strong, resulting in a large difference between the test results and the actual application. Moreover, the correspondence between the excitation amplitude magnitude and the vibration magnitude at the mounting position of the actual vehicle conditions is not strong, making the dynamic stiffness parameter of the bushing obtained by the test have weak reference value when applied to the NVH performance design of the whole vehicle. These problems limit the application value of the traditional dynamic stiffness testing methods in the optimization of vehicle NVH performance. Summary of the Invention

[0005] The main purpose of the present invention is to propose a method for testing a suspension bushing, aiming to obtain the dynamic stiffness parameter of the mounting bushing, so as to provide reference data for the NVH performance design of the whole vehicle.

[0006] To achieve the above object, the method for testing a suspension bushing proposed by the present invention includes:

[0007] Obtaining the static reaction force F received by the suspension bushing according to different working conditions of the vehicle n mj ;

[0008] Based on the static reaction force F n mj, a two-way dynamic stiffness test device applies bidirectional loads to the suspension bushing in a first direction, a second direction, and a third direction, and the first direction, the second direction, and the third direction are perpendicular to each other in pairs;

[0009] Obtain the mechanical performance data of the suspension bushing under each of the bidirectional loads;

[0010] According to the mechanical performance data, calculate the dynamic stiffness parameter k of the suspension bushing n dmj .

[0011] In an embodiment of the present invention, before the step of obtaining the mechanical performance data of the suspension bushing under each of the bidirectional loads, it further includes:

[0012] Fix the suspension bushing on a test fixture, and the test fixture is connected to a two-way dynamic stiffness test device;

[0013] Drive the two-way dynamic stiffness test device to apply the bidirectional loads in the first direction, the second direction, and the third direction to the test fixture.

[0014] In an embodiment of the present invention, the obtaining of the static reaction force received by the suspension bushing according to different working conditions of the vehicle includes:

[0015] According to different working conditions of the vehicle, obtain different wheel-end torques T of the vehicle n w ;

[0016] According to each of the wheel-end torques T n w , obtain the static reaction forces F of the suspension bushing in the first direction, the second direction, and the third direction n mj .

[0017] In an embodiment of the present invention, the obtaining of the static reaction forces F of the suspension bushing in the first direction, the second direction, and the third direction according to each of the wheel-end torques T n w , includes: n mj According to each of the wheel-end torques T

[0018] Apply the gravity of the powertrain at the centroid of the vehicle powertrain and apply the wheel-end torque T at the axis of the engine crankshaft n w ; n w ;

[0019] When the suspension bushing reaches static balance, calculate the static reaction forces F of the suspension bushing in the first direction, the second direction, and the third direction n mj .

[0020] In an embodiment of the present invention, the wheel-end torque T of the vehicle under different working conditions is obtained n w , including:

[0021] According to different working conditions of the vehicle, obtain the output torque T of the vehicle engine under each working condition n e , the gear ratio i of the transmission n t , the gear ratio i of the main reducer n r and the transmission efficiency η of the vehicle transmission system n ;

[0022] According to the calculation formula, obtain the wheel-end torque T of the vehicle under different conditions n w .

[0023] In an embodiment of the present invention, the step of fixing the suspension bushing on the test fixture, and the test fixture is connected to the two-way dynamic stiffness test equipment, includes:

[0024] Fix the two connection surfaces of the suspension bushing in the first direction, the second direction, and the third direction on the two corresponding fixed surfaces of the test fixture respectively, and the back surfaces of any two fixed surfaces in each direction are respectively connected to the two-way dynamic stiffness test equipment.

[0025] Before the step of fixing the suspension bushing on the test fixture, and the test fixture is connected to the two-way dynamic stiffness test equipment in an embodiment of the present invention, further includes:

[0026] Design the test fixture according to the dynamic stiffness simulation experiment of the suspension bushing;

[0027] Conduct a constraint modal analysis on the test fixture in the state with boundaries.

[0028] In an embodiment of the present invention, the mechanical performance data includes the actual dynamic force, actual amplitude, and phase angle of the suspension bushing.

[0029] In an embodiment of the present invention, the step of controlling the two-way dynamic stiffness test equipment to apply bidirectional loads on the test fixture in the first direction, the second direction, and the third direction includes:

[0030] Control the two-way dynamic stiffness testing device to apply swept-frequency excitation at a first frequency and a second frequency to the test tooling;

[0031] Obtain the bidirectional loads of the suspension bushing under each swept-frequency excitation, and control the two-way dynamic stiffness testing device to apply bidirectional loads in the first direction, the second direction, and the third direction to the test tooling.

[0032] The present invention also provides a test tooling, including an upper fixture and a lower fixture; the upper fixture includes first fixing surfaces respectively along a first direction, a second direction, and a third direction, and the lower fixture includes second fixing surfaces adapted to the first fixing surfaces in each direction. Any two opposite first fixing surfaces and second fixing surfaces can be connected to the connecting surfaces of the hanging bushing;

[0033] Wherein, the back surface of any one of the first fixing surfaces of the upper fixture is configured to connect to the upper support of the two-way dynamic stiffness testing device, and the back surface of any one of the second fixing surfaces of the lower fixture is configured to connect to the lower support of the two-way dynamic stiffness testing device.

[0034] In the technical solution of the present invention, by simulating the static reaction forces and dynamic loads under typical working conditions of the vehicle's NVH performance, this testing method can accurately test the dynamic stiffness parameters of the suspension bushing, which helps to more precisely evaluate the performance of the bushing under actual use conditions. Moreover, different from the traditional unidirectional preloading testing method, this solution can achieve multi-directional preloading, more comprehensively simulate the actual working conditions, and thus provide more accurate test results; further, accurate dynamic stiffness parameters are crucial for optimizing the NVH performance of the vehicle, and this technical solution helps to improve the ride comfort and handling stability of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the structures shown in these drawings without creative efforts.

[0036] Figure 1 It is a schematic flowchart of the suspension bushing testing method provided by the present invention;

[0037] Figure 2 It is a flowchart of step S210 in an embodiment of the suspension bushing testing method provided by the present invention;

[0038] Figure 3 It is a flowchart of step S2110 in an embodiment of the suspension bushing testing method provided by the present invention;

[0039] Figure 4 Flow chart of step S2120 in an embodiment of the suspension bushing test method provided by the present invention;

[0040] Figure 5 Flow chart of step S400 in an embodiment of the suspension bushing test method provided by the present invention;

[0041] Figure 6 General flow chart of the suspension bushing test method provided by the present invention;

[0042] Figure 7 Test assembly drawing of the test tooling provided by the present invention in the first direction;

[0043] Figure 8 Test assembly drawing of the test tooling provided by the present invention in the second direction;

[0044] Figure 9 Test assembly drawing of the test tooling provided by the present invention in the third direction;

[0045] Figure 10 Dynamic stiffness test data graph of the suspension bushing obtained by the suspension bushing test method provided by the present invention;

[0046] Figure 11 Model test graph of the suspension bushing test method provided by the present invention.

[0047] Explanation of the reference numerals in the drawings:

[0048] 10. Upper fixture; 20. Lower fixture; 11. First fixing surface; 21. Second fixing surface;

[0049] The realization, functional features and advantages of the object of the present invention will be further described in conjunction with the embodiments and with reference to the accompanying drawings. Detailed implementation manners

[0050] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0051] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0052] In addition, if descriptions such as "first" and "second" are involved in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, or scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0053] The suspension bushing test method proposed by the present invention includes:

[0054] Step S210: Obtain the static reaction force F received by the suspension bushing according to different working conditions of the vehicle n mj ;

[0055] Step S220: Based on the static reaction force F n mj , a two-way dynamic stiffness test device applies bidirectional loads in a first direction, a second direction, and a third direction to the suspension bushing, and the first direction, the second direction, and the third direction are perpendicular to each other in pairs;

[0056] Step S500: Obtain the mechanical performance data of the suspension bushing under each of the bidirectional loads;

[0057] Step S600: Calculate the dynamic stiffness parameter k of the suspension bushing based on the mechanical performance data n dmj .

[0058] Explain step S210. Different working conditions of the vehicle include the working conditions of traditional fuel vehicles and new energy vehicles. For traditional fuel vehicles, typical working conditions for the vehicle's NVH performance include: N - gear idle condition, R - gear idle condition, D1 - gear gentle acceleration condition (1POT), and 3 - gear full - throttle acceleration condition (3WOT); for new energy vehicles, typical working conditions for the vehicle's NVH performance include: idle charging (including feed - in charging) condition, D - gear gentle acceleration condition (POT), and D - gear full - throttle acceleration condition (WOT); based on this, obtain the static reaction force F received by the vehicle's suspension bushings under different working conditions n mj , such as the left suspension bushing and the right suspension bushing, how to obtain the static reaction force F nmj , which will be explained later. Among them, the static reaction force F received by the suspension bushing under each working condition n mj includes the static reaction forces F received in three directions of the U direction, V direction, and W direction n mj , where the U direction, V direction, and W direction respectively correspond to the Y-axis, X-axis, and Z-axis directions of the three-dimensional Cartesian coordinate system. Among them, based on the installation position and force conditions of the suspension bushing in the vehicle assembly, the static reaction forces F received by the suspension bushing in the U direction, V direction, and W direction n mj are all bidirectional loads with two opposite acting directions.

[0059] Step S220: According to the static reaction force F n mj , the two-way dynamic stiffness testing equipment applies bidirectional loads in the first direction, second direction, and third direction to the suspension bushing. The first direction, the second direction, and the third direction are perpendicular to each other pairwise. Among them, the bidirectional load applied by the two-way dynamic stiffness testing equipment to the suspension bushing is the static reaction force F received by the suspension bushing under different vehicle working conditions n mj , and the two-way dynamic stiffness testing equipment needs to perform three mechanical tests on the suspension bushing in different directions in sequence. The first direction, the second direction, and the third direction respectively correspond to the U direction, V direction, and W direction, so as to simulate the force conditions of the suspension bushing under different vehicle working conditions. Through the test and evaluation of the suspension bushing in multiple directions by the two-way dynamic stiffness testing equipment, the comprehensive mechanical performance of the suspension bushing can be obtained, which is convenient for optimizing the NVH performance of the vehicle.

[0060] Step S500: Obtain the mechanical performance data of the suspension bushing under each bidirectional load. Among them, relevant data is recorded by using devices such as sensors and industrial cameras. The mechanical performance data is the test result of the suspension bushing in each direction, including the actual dynamic force, actual amplitude, and phase angle of the suspension bushing. In one embodiment, record the actual dynamic force (F 3WOT 左U , F 3WOT 左V , F 3WOT 左W , F 2POT 左U , F 2POT 左V , F 2POT 左W ), actual amplitude (S 3WOT 左U , S 3WOT 左V , S3WOT 左W , S 2POT 左U , S 2POT 左V , S 2POT 左W ), and phase angle (θ 3WOT 左U , θ 3WOT 左V , θ 3WOT 左W , θ 2POT 左U , θ 2POT 左V , θ 2POT 左W ).

[0061] Step S600: Calculate the dynamic stiffness parameter (k n dmj , unit: N / mm) of the suspension bushing according to the mechanical performance data, and at the same time obtain the dynamic damping coefficient (ζ n dmj , unit: -). The dynamic stiffness parameter k n dmj is based on the actual dynamic force (F n dmj , unit: N), actual amplitude (S n dmj , unit: mm), and phase angle (θ n dmj , unit: degree) and is obtained as follows. The specific calculation formula is as follows:

[0062] ,

[0063] where k n d1mj , k n d2mj are the storage stiffness and loss stiffness respectively. The dynamic stiffness and dynamic damping coefficient can be expressed as:

[0064]

[0065]

[0066] In the technical solution of the present invention, by simulating the static reaction forces and dynamic loads under typical vehicle NVH performance conditions, this test method can accurately measure the dynamic stiffness parameters of the mount bushing, which helps to more precisely evaluate the performance of the bushing under actual use conditions. Moreover, different from the traditional unidirectional preloading test method, this solution can achieve multi-directional preloading, more comprehensively simulate the actual working conditions, and thus provide more accurate test results, enriching the test theory of the mount bushing stiffness. Further, accurate dynamic stiffness parameters are crucial for optimizing the NVH performance of the vehicle, and this technical solution helps to improve the ride comfort and handling stability of the vehicle.

[0067] In an embodiment of the present invention, before step S500, it further includes:

[0068] Step S300: Fix the suspension bushing on the test fixture, and the test fixture is connected to a two-way dynamic stiffness test device.

[0069] Step S400: Drive the two-way dynamic stiffness test device to apply the bidirectional loads in the first direction, the second direction, and the third direction to the test fixture.

[0070] For step S300, first, a special test fixture needs to be prepared. This fixture is designed to simulate the actual installation position and force conditions of the suspension bushing on the vehicle, that is, the test fixture includes an inner side connected to the mount bushing and an outer side connected to the two-way dynamic stiffness test device, so that the two-way dynamic stiffness test device can apply bidirectional loads to the test fixture, and the action of the bidirectional loads is transmitted to the suspension bushing to be tested, thereby obtaining the required mechanical performance data.

[0071] For step S400, during the test, by using the two-way dynamic stiffness test device to apply the bidirectional loads in the first direction, the second direction, and the third direction to the test fixture respectively. During this process, the connection surface of the mount bushing needs to be changed multiple times. Specifically, when testing the dynamic stiffness of the mount bushing in the U direction, the installation method of the test fixture can be referred to Figure 7 , and the corresponding preloads are given in the U direction and the W direction Figure 10 . At this time, a first load is applied to the test fixture in the U direction, and a second load is applied to the test fixture in the W direction. Specifically, the two test bench supports of the two-way dynamic stiffness test device slowly apply the first load in the U direction until it is equal to the static reaction force, and the two test bench supports stop moving in the U direction. Subsequently, the two-way dynamic stiffness test device drives the test bench supports to translate in the W direction, so as to obtain the second load in the W direction until it is equal to the static reaction force, thereby obtaining the dynamic stiffness parameter of the mount bushing in the U direction;

[0072] When testing the dynamic stiffness of the mount bushing in the V direction, the installation method of the test fixture can be referred to Figure 8 , and a given value is provided in the V directionFigure 10 Corresponding to the preload, at this time, a first load is applied to the test tooling in the V direction, and a second load is applied to the test tooling in the W direction. Specifically, the two test bench supports of the two-way dynamic stiffness test equipment slowly apply the first load in the V direction to the equivalent static reaction force. The two test bench supports stop moving in the V direction. Subsequently, the two-way dynamic stiffness test equipment drives the test bench supports to translate in the W direction, so as to obtain the second load in the W direction to the equivalent static reaction force, and thus obtain the dynamic stiffness parameter of the suspension bushing in the V direction;

[0073] When testing the dynamic stiffness of the suspension bushing in the W direction, for the installation method of the test tooling, please refer to Figure 9 , and a given value is provided in the W direction Figure 10 Corresponding to the preload, at this time, a first load is applied to the test tooling in the W direction, and a second load is applied to the test tooling in the U direction. Specifically, the two test bench supports of the two-way dynamic stiffness test equipment slowly apply the first load in the W direction to the equivalent static reaction force. The two test bench supports stop moving in the W direction. Subsequently, the two-way dynamic stiffness test equipment drives the test bench supports to translate in the U direction, so as to obtain the second load in the U direction to the equivalent static reaction force, and thus obtain the dynamic stiffness parameter of the suspension bushing in the W direction;

[0074] Among them, Figure 10 The data in are obtained from two working conditions: full throttle acceleration in the third gear of the whole vehicle and slow throttle acceleration in the second gear of the whole vehicle. The specific method will be explained below.

[0075] In an embodiment of the present invention, step S210 includes:

[0076] Step S2110: Obtain different wheel side torques T of the vehicle according to different working conditions of the vehicle n w ;

[0077] Step S2120: According to each of the wheel side torques T n w , obtain the static reaction forces F of the suspension bushing in the first direction, the second direction, and the third direction n mj .

[0078] It should be explained that the static reaction force F n mj refers to the static load borne at the elastic center of the suspension under typical working conditions of the vehicle NVH performance. Further explanation: The output torque of the power assembly will be transmitted to the vehicle body through the suspension, thus generating a force at the suspension. The wheel side torque is the torque generated after the output torque of the power assembly is transmitted to the driving wheels through the transmission system. It directly reflects the traction or braking force of the power assembly on the vehicle body. Therefore, by inputting the wheel side torque T under different working conditions of the vehicle into Adams or Matlabn w ,Further analysis by Adams or Matlab yields the static reaction forces F of the suspension bushing in the first direction, the second direction, and the third direction n mj。

[0079] In an embodiment of the present invention, step S2120 includes:

[0080] Step S2121: According to each of the wheel-end torques T n w , apply the gravity of the powertrain at the centroid of the automotive powertrain and apply the wheel-end torque T at the axis of the engine crankshaft n w ;

[0081] Step S2122: When the suspension bushing reaches static equilibrium, calculate the static reaction forces F of the suspension bushing in the first direction, the second direction, and the third direction n mj .

[0082] Regarding step S2121, applying the gravity of the powertrain at the centroid of the powertrain can simulate the effect of the weight of the powertrain itself on the mounts, reflecting the influence of the mass of the powertrain itself on the mounts; applying the wheel-end torque T at the axis of the engine crankshaft nw , can simulate the effect of the torque output by the engine on the mounts, reflecting the influence of the torque output by the powertrain on the mounts; the force exerted by the powertrain on the mounts can be decomposed into two component forces, one along the direction from the center of gravity of the powertrain to the mounts, and the other along the direction from the axis of the engine crankshaft to the mounts. Therefore, applying the gravity of the powertrain at the centroid of the powertrain and applying the wheel-end torque T nw at the axis of the engine crankshaft can more accurately simulate the effect of the powertrain on the mounts. In an example, the gravity of the assembly is 2075N, and thus the wheel-end torque T nw is 1793 Nm during full-throttle acceleration in the third gear, and the wheel-end torque T nw is 1250 Nm during slow-throttle acceleration in the second gear. How to obtain the wheel-end torque T of the vehicle under different working conditions through the gravity of the assembly nw will be explained later.

[0083] Regarding step S2122, it should be explained that, based on obtaining different wheel-end torques T n w , slowly apply the gravity of the powertrain (2075N) at the centroid of the powertrain and apply the wheel-end torque T at the axis of the engine crankshaft respectively nw(When accelerating at full throttle in the third gear, the torque is 1793 Nm; when accelerating with a gentle throttle in the second gear, the torque is 1250 Nm). When reaching static balance, calculate the static reaction force of the elastic center of the mounting bushing, and decompose the static reaction force in each translational direction of the left mount. The obtained static reaction force is the output value of the two-way dynamic stiffness test equipment.

[0084] In an embodiment of the present invention, step S2110 includes:

[0085] Step S2111: According to different working conditions of the vehicle, obtain the output torque T of the vehicle engine under each working condition n e , the gear ratio i of the transmission n t , the gear ratio i of the final drive n r and the transmission efficiency η of the vehicle transmission system n ;

[0086] Step S2112: According to the calculation formula, obtain the wheel side torque T of the vehicle under different conditions n w .

[0087] It can be understood that for each vehicle condition, there is a fixed output torque T of the vehicle engine n e , the gear ratio i of the transmission n t , the gear ratio i of the final drive n r and the transmission efficiency η of the vehicle transmission system n . Specifically, for the full-throttle acceleration condition in the third gear of the whole vehicle, at this time, the output torque T 3 e is 280 Nm, the gear ratio i of the transmission 3 t is 1.59, the gear ratio i of the final drive 3 r is 4.24, and the torque transmission efficiency η3 is 95%; for the gentle-throttle acceleration condition in the second gear, at this time, the output torque T 2 e is 130 Nm, the gear ratio i of the transmission 2 t is 2.82, the gear ratio i of the final drive 2 r is 3.79, and the torque transmission efficiency η2 is 90%. Through the following calculation formula, it can be obtained:

[0088] ;

[0089] ,

[0090] Based on the above output wheel-end torque T n w , the static reaction forces F of the suspension bushing in the U, V, and W directions can be obtained n mj , as shown in the table:

[0091]

[0092] In an embodiment of the present invention, when fixing the suspension bushing on the test fixture, the test fixture is connected to a two-way dynamic stiffness test device, including:

[0093] Fix the two connecting surfaces of the suspension bushing in the first direction, the second direction, and the third direction on the two matching fixing surfaces of the test fixture respectively. The back of any two fixing surfaces in each direction is respectively connected to the two-way dynamic stiffness test device. Specifically, when testing the dynamic stiffness of the suspension bushing in the U direction, for the installation method of the test fixture, please refer to Figure 7 , the suspension bushing is vertically connected to the two fixing surfaces on the test fixture in the height direction;

[0094] When testing the dynamic stiffness of the suspension bushing in the V direction, for the installation method of the test fixture, please refer to Figure 8 , the suspension bushing is vertically connected to the two fixing surfaces on the test fixture in the width direction;

[0095] When testing the dynamic stiffness of the suspension bushing in the W direction, for the installation method of the test fixture, please refer to Figure 9 , the suspension bushing is horizontally connected to the two fixing surfaces on the test fixture in the length direction. The design method of the test fixture is explained below.

[0096] In an embodiment of the present invention, before step S300, it further includes:

[0097] Step S110: Design the test fixture according to the dynamic stiffness simulation experiment of the suspension bushing;

[0098] Step S120: Perform a constrained modal analysis on the test fixture in the boundary state.

[0099] For step S110, design the structure of the test fixture according to the dynamic stiffness simulation experiment of the suspension bushing. Specifically, the test fixture includes an upper fixture and a lower fixture. The upper fixture and the lower fixture enclose a limiting space for installing the suspension bushing. Among them, both the upper fixture and the lower fixture have three fixing surfaces, and every two fixing surfaces are adjacent. The back of each fixing surface is used to connect the two support seats of the two-way dynamic stiffness test device, so as to realize the two-way dynamic stiffness test device applying bidirectional loads in the first direction, the second direction, and the third direction to the suspension bushing.

[0100] For step S120, in order to avoid the influence of the vibration of the test tooling itself on the test results and improve the accuracy and reliability of the test results, the first-order modal frequency of the test tooling is greater than 1.5 times the upper limit value of the frequency range to be tested. For example, if the frequency range concerned in the dynamic stiffness parameter test of the suspension bushing is 0 - 500 Hz, then the first-order modal frequency of the test tooling with boundary conditions should be greater than 750 Hz.

[0101] In an embodiment of the present invention, the mechanical performance data includes the actual dynamic force, actual amplitude, and phase angle of the suspension bushing.

[0102] In an embodiment of the present invention, step S400 includes:

[0103] Step S410: Control the two-way dynamic stiffness test equipment to apply swept-frequency excitation at a first frequency and a second frequency to the test tooling;

[0104] Step S420: Obtain the bidirectional loads of the suspension bushing under each swept-frequency excitation, and control the two-way dynamic stiffness test equipment to apply bidirectional loads in the first direction, the second direction, and the third direction to the test tooling.

[0105] For step S410, the swept-frequency excitation can cover the resonance frequencies that the suspension bushing may occur, as well as the common vibration frequency ranges during vehicle driving, such as idle vibration, acceleration vibration, road noise, etc. By applying swept-frequency excitation at different frequencies to the test tooling, various vibration frequencies that the suspension bushing may encounter during actual operation are simulated, so as to more comprehensively evaluate the dynamic stiffness characteristics of the suspension bushing.

[0106] For step S420, by measuring the actual dynamic force, actual amplitude, and phase angle of the suspension bushing at different frequencies and loads, the dynamic stiffness parameters and dynamic damping coefficients of the suspension bushing can be calculated, thereby evaluating the vibration isolation performance of the suspension bushing. Through swept-frequency excitation and data analysis, the mechanical performance of the suspension bushing at different frequencies and loads can be obtained, providing important data support for the vehicle NVH performance design.

[0107]

[0108] Based on the above data, the dynamic stiffness data performance of the suspension bushing under full throttle acceleration in the third gear of the vehicle and slow throttle acceleration in the second gear of the vehicle is obtained.

[0109] The present invention also provides a test fixture, which includes an upper fixture 10 and a lower fixture 20; the upper fixture 10 includes a first fixing surface 11 along the first direction, the second direction and the third direction respectively, and the lower fixture 20 includes a second fixing surface 21 adapted to the first fixing surface 11 in each direction. Any two opposite first fixing surfaces 11 and second fixing surfaces 21 can be connected to the suspension bushing.

[0110] Wherein, the back surface of any one of the first fixing surfaces 11 of the upper fixture 10 is configured to be connected to the upper support on the test bench of the two-way dynamic stiffness test equipment, and the back surface of any one of the second fixing surfaces 21 of the lower fixture 20 is configured to be connected to the lower support on the test bench of the two-way dynamic stiffness test equipment.

[0111] Specifically, each fixing surface of the upper fixture 10 and the lower fixture 20 is provided with a plurality of screw holes for screwing the upper support on the test bench, the lower support on the test bench and the suspension bushing. As Figures 7 to 9 shown, a set of test fixtures can be used to test the two-way preload dynamic stiffness of the suspension bushing in three translational directions. The test fixture has a simple structure, is convenient for installation with variable directions, and has the characteristics of strong applicability, wide test frequency range and high test result accuracy.

[0112] The above is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied to other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A suspension bushing testing method, characterized in that: The suspension bushing test method includes: According to different working conditions of the car, different wheel torque T of the car is obtained. n w ; According to the wheel side moment T n w , the powertrain gravity is applied at the center of mass of the vehicle powertrain and the wheel torque T is applied at the axis of the engine crankshaft n w ; When the suspension bushing reaches static equilibrium, the static support reaction force F of the suspension bushing in the first direction, the second direction and the third direction is calculated. n mj ; According to the static support reaction force F n mj , a two-way dynamic stiffness test device applies a bidirectional load in a first direction, a second direction and a third direction to the suspension bushing, wherein the first direction, the second direction and the third direction are perpendicular to each other; Acquiring mechanical performance data of the suspension bushing under each of the bidirectional loads; According to the mechanical performance data, the dynamic stiffness parameter k of the suspension bushing is calculated. n dmj ; Wherein, the static support reaction force F n mj It is a bidirectional load received in the first direction, the second direction and the third direction.

2. The suspension bushing testing method according to claim 1, characterized in that: Before the step of obtaining the mechanical performance data of the suspension bushing under each of the bidirectional loads, the method further includes: Fixing the suspension bushing on a test fixture, wherein the test fixture is connected to a two-way dynamic stiffness test device; The two-way dynamic stiffness testing device is driven to apply the two-way loads in the first direction, the second direction and the third direction to the testing fixture.

3. The suspension bushing testing method according to claim 1, characterized in that: According to different working conditions of the vehicle, different wheel side torques T of the vehicle are obtained. n w ,include: According to different working conditions of the car, the output torque T of the car engine under each working condition is obtained. n e , the speed ratio of the transmission n t , speed ratio of the main reducer i n r And the transmission efficiency η of the automobile transmission system n ; According to the calculation formula, different wheel torques T of the car are obtained. n w .

4. The suspension bushing testing method according to claim 2, characterized in that: The suspension bushing is fixed on a test fixture, and the test fixture is connected to a two-way dynamic stiffness test device, including: Respectively fix the two connecting surfaces of the suspension bushing along the first direction, the second direction and the third direction to the two fixed surfaces adapted on the test fixture, and the back sides of any two of the fixed surfaces in each direction are respectively connected to the two-way dynamic stiffness test equipment; Wherein, the test fixture comprises an upper fixture and a lower fixture; the upper fixture comprises first fixing surfaces along a first direction, a second direction and a third direction respectively, and the lower fixture comprises a second fixing surface adapted to the first fixing surface along each direction, and any two opposite first fixing surfaces and second fixing surfaces can be connected to the connection surface of the suspension bushing; Among them, the back side of any one of the first fixing surfaces of the upper clamp is configured to be connected to the upper support of the two-way dynamic stiffness testing device, and the back side of any one of the second fixing surfaces of the lower clamp is configured to be connected to the lower support of the two-way dynamic stiffness testing device.

5. The suspension bushing testing method according to claim 4, characterized in that: Before the step of fixing the suspension bushing on the test fixture and connecting the test fixture to the two-way dynamic stiffness test equipment, the method further includes: Designing the test fixture according to the dynamic stiffness simulation experiment of the suspension bushing; A constrained modal analysis is performed on the test fixture with boundary states.

6. The suspension bushing testing method according to claim 1, characterized in that: The mechanical performance data includes the actual dynamic force, actual amplitude and phase angle of the suspension bushing.

7. The suspension bushing testing method according to claim 2, characterized in that: The step of driving the two-way dynamic stiffness testing device to apply a bidirectional load in the first direction, the second direction and the third direction to the testing fixture comprises: Controlling the two-way dynamic stiffness testing device to apply a swept frequency excitation of a first frequency and a second frequency to the testing fixture; The bidirectional load on the suspension bushing under each frequency sweep excitation is obtained, and the two-way dynamic stiffness test equipment is controlled to apply bidirectional loads in the first direction, the second direction and the third direction to the test fixture.

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