Method for verifying automobile height based on suspension hard point

Abstract

The invention belongs to the technical field of vehicle engineering target testing, and particularly relates to a method for verifying the height of a vehicle based on a suspension hard point. Reloading a sample piece, refueling a test vehicle, calibrating tire pressure, and carrying out a dynamic inspection test; the hard point height DMU analyzes and obtains theoretical heights of an inner front point of a front lower control arm and an inner point of a rear lower control arm of the test vehicle in the no-load state of the whole vehicle, actually measures and obtains actual heights of the inner front point of the front lower control arm and the inner point of the rear lower control arm of the test vehicle in the no-load state, and calculates and corrects the spring load; and manufacturing a front spiral spring and a rear spiral spring according to the no-load correction value, and obtaining the actual height of the inner front point of the front lower control arm and the inner point of the rear lower control arm of the test vehicle in the no-load state until the actual height is the same as the theoretical height. And the height of the automobile is adjusted by converting the lever ratio of the spring and reversely pushing the no-load load of the spring.

Description

Technical Field

[0001] The invention belongs to the technical field of vehicle engineering target testing, and in particular relates to a method for verifying the height of a vehicle based on suspension hard points. Background Art

[0002] Vehicle height, that is, the distance from the highest point of the vehicle to the support plane, is a public parameter in the vehicle engineering target, which affects the vehicle's performance such as power, passability and handling stability. However, due to the control accuracy of the vehicle's curb weight, the actual deformation of the suspension coil spring is different from the theory, resulting in a difference in vehicle height. Ultimately, this part of the deviation needs to be compensated by correcting the no-load load of the spring. At present, there are generally two methods for measuring vehicle height. The first method is to use special inspection tools or three-coordinate measurement, which has high accuracy, but the operation is complicated and not suitable for control in the trial production stage; the second method is to indirectly measure the wheel opening height, which is simple to operate, but is limited by the dimensional accuracy of the body parts and the flatness of the ground, and the control effect will be worse. In general, the tolerance requirements for vehicle height are ±1%, and the tolerance requirements for wheel opening height are ±3, but due to the influence of the dimension chain, the control difficulty of these two parameters is relatively high. Summary of the invention

[0003] In order to overcome the above problems, the present invention provides a method for verifying the height of a car based on the suspension hard point. Based on the concept of the ground clearance of the whole vehicle, the height of the suspension hard point is used instead of the vehicle height, and the method for adjusting the height of the car is achieved by converting the spring lever ratio and pushing back the spring no-load load.

[0004] A method for verifying the height of a vehicle based on suspension hard points, comprising the following contents:

[0005] Step 1: Sample replacement: Replace the front and rear coil springs of the test vehicle with the front and rear coil springs whose stiffness and no-load load have been measured, wherein the stiffness of the replaced front and rear coil springs are K1 and K2 respectively, and the no-load load of the replaced front and rear coil springs are P1 and P2 respectively;

[0006] Step 2: Refuel the test vehicle;

[0007] Step 3: Tire pressure calibration;

[0008] Step 4: The test vehicle undergoes dynamic inspection test;

[0009] Step 5: Hard point height DMU analysis The theoretical heights of the front point inside the front lower control arm and the rear lower control arm inside the test vehicle under the unloaded state are recorded as H1 and H2 respectively;

[0010] Step 6: Hard point height measurement: Measure the actual height of the front point inside the front lower control arm and the inner point of the rear lower control arm of the test vehicle under no-load condition on the test platform, and record them as H1' and H2' respectively;

[0011] Step 7: Correct spring load: The no-load load correction values ​​of the front and rear coil springs are P1'=P1-(H3-H1)*I1*K1, P2'=P2-(H4-H2) / I2*K2, where I1 and I2 are the known lever ratios of the front and rear coil springs respectively;

[0012] Step 8: According to the no-load load correction value of the front and rear coil springs calculated in step 7, new front and rear coil springs are made, and then the newly made front and rear coil springs are installed on the test vehicle. The actual heights H1” and H2” of the front point inside the front lower control arm and the inner point inside the rear lower control arm of the test vehicle under no-load condition are measured through step 6, and H1” and H2” are compared with H1 and H2 in step 5 respectively. If H1”=H1 and H2”=H2, it means that the vehicle height meets the requirements, otherwise it means that the vehicle height does not meet the requirements.

[0013] In the step 2, the test vehicle is refueled, and the refueling amount can ensure the vehicle's curb weight.

[0014] In step three, the tire pressure of the test vehicle is calibrated to 2.5 bar.

[0015] In the step 5, the theoretical heights of the front inner point of the front lower control arm and the inner point of the rear lower control arm of the test vehicle when the vehicle is unloaded refer to the vertical distances of these two points from the ground line.

[0016] The hard point height DMU analysis in step five utilizes the ground line, the test vehicle suspension DMU model and the test vehicle suspension 3D data to simulate and analyze the theoretical heights of the front inner point of the front lower control arm and the inner point of the rear lower control arm of the test vehicle when the vehicle is unloaded.

[0017] In step six, the actual heights of the front inner point of the front lower control arm and the inner point of the rear lower control arm of the test vehicle in the no-load state refer to the vertical distances of these two points from the ground line respectively.

[0018] When the vehicle height does not meet the requirement in step eight, steps one to eight are repeated until H1"=H1 and H2"=H2.

[0019] In the step 4, the dynamic inspection test of the test vehicle is performed to remove the spring assembly stress so that the vehicle height tends to be stable.

[0020] Beneficial effects of the present invention:

[0021] Since the processing accuracy of parts such as the front lower control arm and the rear lower control arm is high and the deformation after loading is small, the present invention uses their geometric size characteristics, that is, the height of the suspension hard point (the front point inside the front lower control arm and the inner point of the rear lower control arm, etc.) to replace the vehicle height, and then adjusts the vehicle height by controlling the hard point height. This method has high accuracy and a simple measurement process. It is a simple and effective means of controlling the vehicle height in the trial production stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without creative work.

[0023] Figure 1 This is a schematic diagram of the hard point height DMU analysis of the present invention.

[0024] Figure 2 This is another schematic diagram of the hard point height DMU analysis of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0026] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0028] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0029] Example 1

[0030] A method for verifying the height of a vehicle based on suspension hard points, comprising the following contents:

[0031] Step 1: Sample replacement: Replace the front and rear coil springs of the test vehicle with the front and rear coil springs whose stiffness and no-load load have been measured, wherein the stiffness of the replaced front and rear coil springs are K1 and K2 respectively, and the no-load load of the replaced front and rear coil springs are P1 and P2 respectively;

[0032] Step 2: Refuel the test vehicle to ensure the vehicle's curb weight;

[0033] Step 3: Tire pressure calibration: Calibrate the tire pressure of the test vehicle to 2.5 bar;

[0034] Step 4: Perform a dynamic inspection test on the test vehicle to remove the spring assembly stress and stabilize the vehicle height;

[0035] Step 5: If Figure 1-2 As shown, hard point height DMU analysis: using the ground line, the test vehicle suspension DMU model and the test vehicle suspension 3D data to simulate and analyze the theoretical heights of the front point inside the front lower control arm and the rear lower control arm inside the test vehicle in the unloaded state, recorded as H1 and H2 respectively;

[0036] Step 6: Hard point height measurement: Measure the actual height of the front point inside the front lower control arm and the inner point of the rear lower control arm of the test vehicle under no-load condition on the test platform, and record them as H1' and H2' respectively;

[0037] Step 7: Correct spring load: Given the lever ratio of the front and rear coil springs (the lever ratio of the same type of front and rear coil springs installed on the same model of vehicle is fixed), record them as I1 and I2 respectively, then the no-load load correction values ​​of the front and rear coil springs are P1'=P1-(H3-H1)*I1*K1, P2'=P2-(H4-H2) / I2*K2 respectively;

[0038] Step 8: According to the no-load load correction value of the front and rear coil springs calculated in step 7, new front and rear coil springs are made, and then the newly made front and rear coil springs are installed on the test vehicle. The actual heights H1” and H2” of the front point inside the front lower control arm and the rear lower control arm inside the test vehicle in the no-load state are measured through step 6. H1” and H2” are compared with H1 and H2 in step 5 respectively. If H1”=H1 and H2”=H2, it means that the vehicle height meets the requirements. Otherwise, it means that the vehicle height does not meet the requirements. Repeat steps 1 to 8 until H1”=H1 and H2”=H2.

[0039] In the step 5, the theoretical heights of the front inner point of the front lower control arm and the inner point of the rear lower control arm of the test vehicle when the vehicle is unloaded refer to the vertical distances of these two points from the ground line.

[0040] In step six, the actual heights of the front inner point of the front lower control arm and the inner point of the rear lower control arm of the test vehicle in the no-load state refer to the vertical distances of these two points from the ground line respectively.

[0041] Example 2

[0042] Step 1: Replace the test specimens of the coil springs before and after installation, and record their measured stiffness and no-load load, which are recorded as K1, K2,

[0043] Step 2: Refuel the test vehicle: ensure the vehicle's curb weight;

[0044] Step 3: Tire pressure calibration: Calibrate the tire pressure to 2.5 bar to ensure the deformation of the tire;

[0045] Step 4: Dynamic inspection test: Remove the spring assembly stress to make the vehicle height stable;

[0046] Step 5: Hard point height DMU analysis: Use the ground line, suspension DMU model and suspension 3D data to simulate and analyze the theoretical height of the front point inside the front lower control arm and the rear lower control arm inside the vehicle under no-load conditions, recorded as H1 and H2;

[0047] Step 6: Hard point height measurement: Measure the actual height of the front point inside the front lower control arm and the inner point of the rear lower control arm of the test vehicle in the unloaded state on the test platform, and record them as H1' and H2';

[0048] Step 7: Correct spring load: If the spring lever ratios are known to be I1 and I2, the no-load load correction values ​​of the front and rear springs are P1'=P1-(H3-H1)*I1*K1, P2'=P2-(H4-H2) / I2*K2 respectively;

[0049] Step 8: Re-check the vehicle height: Re-adjust the parts and re-check the vehicle height.

[0050] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the protection scope of the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention. These simple variations all belong to the protection scope of the present invention.

[0051] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0052] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for verifying the height of a vehicle based on suspension hard points, characterized in that: It includes the following: Step 1: Sample replacement: Replace the front and rear coil springs of the test vehicle with the front and rear coil springs whose stiffness and no-load load have been measured, wherein the stiffness of the replaced front and rear coil springs are K1 and K2 respectively, and the no-load load of the replaced front and rear coil springs are P1 and P2 respectively; Step 2: Refuel the test vehicle; Step 3: Tire pressure calibration; Step 4: The test vehicle undergoes dynamic inspection test; Step 5: Hard point height DMU analysis The theoretical heights of the front point inside the front lower control arm and the rear lower control arm inside the test vehicle under the unloaded state are recorded as H1 and H2 respectively; Step 6: Hard point height measurement: Measure the actual height of the front point inside the front lower control arm and the inner point of the rear lower control arm of the test vehicle under no-load condition on the test platform, and record them as H1' and H2' respectively; Step 7: Correct spring load: The no-load load correction values ​​of the front and rear coil springs are P1'=P1-(H3-H1)*I1*K1, P2'=P2-(H4-H2) / I2*K2, where I1 and I2 are the known lever ratios of the front and rear coil springs respectively; Step 8: According to the no-load load correction value of the front and rear coil springs calculated in step 7, new front and rear coil springs are made, and then the newly made front and rear coil springs are installed on the test vehicle. The actual heights H1” and H2” of the front point inside the front lower control arm and the inner point inside the rear lower control arm of the test vehicle under no-load condition are measured through step 6, and H1” and H2” are compared with H1 and H2 in step 5 respectively. If H1”=H1 and H2”=H2, it means that the vehicle height meets the requirements, otherwise it means that the vehicle height does not meet the requirements.

2. A method for verifying vehicle height based on suspension hard points according to claim 1, characterized in that: In the step 2, the test vehicle is refueled, and the refueling amount can ensure the vehicle's curb weight.

3. The method for verifying the height of a vehicle based on suspension hard points according to claim 1, characterized in that: In step three, the tire pressure of the test vehicle is calibrated to 2.5 bar.

4. The method for verifying the height of a vehicle based on suspension hard points according to claim 1, characterized in that: In the step 5, the theoretical heights of the front inner point of the front lower control arm and the inner point of the rear lower control arm of the test vehicle when the vehicle is unloaded refer to the vertical distances of these two points from the ground line.

5. The method for verifying the height of a vehicle based on suspension hard points according to claim 1, characterized in that: The hard point height DMU analysis in step five utilizes the ground line, the test vehicle suspension DMU model and the test vehicle suspension 3D data to simulate and analyze the theoretical heights of the front inner point of the front lower control arm and the inner point of the rear lower control arm of the test vehicle when the vehicle is unloaded.

6. The method for verifying the height of a vehicle based on suspension hard points according to claim 1, characterized in that: In step six, the actual heights of the front inner point of the front lower control arm and the inner point of the rear lower control arm of the test vehicle in the no-load state refer to the vertical distances of these two points from the ground line respectively.

7. The method for verifying the height of a vehicle based on suspension hard points according to claim 1, characterized in that: When the vehicle height does not meet the requirement in step eight, steps one to eight are repeated until H1"=H1 and H2"=H2.

8. The method for verifying the height of a vehicle based on suspension hard points according to claim 1, characterized in that: In the step 4, the dynamic inspection test of the test vehicle is performed to remove the spring assembly stress so that the vehicle height tends to be stable.

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