A shock absorber pre-tightening force test system and a test method

Abstract

The present invention discloses a shock absorber pre-tightening force test system and a test method, which relate to the field of automotive shock absorbers and include a strain sensor, etc. The strain sensor is electrically connected to three resistors with the same resistance in the form of a Wheatstone bridge to form a bridge circuit unit. A power supply potential E is applied between the first node and the third node of the bridge circuit unit. An acquisition unit is electrically connected to the second node and the fourth node for acquiring and measuring the potential e0. A computer is electrically connected to the acquisition unit for calculating the corresponding strain value according to the measured potential e0 and displaying and recording the strain signal. A power supply is electrically connected to the computer to achieve power supply; the strain sensor is fixed on the cylinder block of the shock absorber to be tested for sensing the strain of the cylinder block. The present invention can conveniently and quickly detect the sealing pre-tightening force of the shock absorber by using the strain sensor, providing data support for improving the sealing quality of the shock absorber and laying a foundation for future research on other performances of the shock absorber.

Description

Technical Field

[0001] The present invention relates to the field of automotive shock absorbers, and particularly to a shock absorber pre-tightening force test system and a test method. Background Art

[0002] A shock absorber is a component widely used in automobiles to suppress the oscillation when the spring rebounds after absorbing shock and the impact from the road surface, so as to accelerate the attenuation of the vibration of the vehicle frame and body and improve the ride comfort of the vehicle. After the shock absorber is sealed, its working cylinder is in a pre-tightened state, and the oil storage cylinder is in a stretched state. When the sealing quality is poor, the shock absorber is prone to abnormal noise and even oil leakage. However, at present, there is not much research on the pre-tightening force in the shock absorber industry, and there is no data support for the sealing pre-tightening force of the shock absorber. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a shock absorber pre-tightening force test system and a test method, which have the advantages of simple structure and convenient testing.

[0004] The purpose of the present invention is achieved by the following technical solutions: A shock absorber pre-tightening force test system includes a strain sensor, a bridge circuit unit, an acquisition unit, a computer, a power supply, and a shock absorber to be tested. The strain sensor is electrically connected to three resistors R1, R2, and R3 with the same resistance value in the form of a Wheatstone bridge as a branch arm to form the bridge circuit unit. A power supply potential E is applied between the first node and the third node of the bridge circuit unit. The power supply is electrically connected between the first node and the third node to provide the power supply potential E. A measurement potential e0 is formed between the second node and the fourth node of the bridge circuit unit. The acquisition unit is electrically connected between the second node and the fourth node to collect the measurement potential e0. The computer is electrically connected to the acquisition unit to calculate the corresponding strain value according to the measurement potential e0 and display and record the strain signal. The power supply is electrically connected to the computer to achieve power supply; the strain sensor is fixed on the cylinder body of the shock absorber to be tested to sense the strain of the cylinder body.

[0005] The test method using the above shock absorber pre-tightening force test system includes the following steps:

[0006] 1) Paste the strain sensor on the cylinder body of the shock absorber to be tested, and then electrically connect the strain sensor to three resistors R1, R2, and R3 with the same resistance value in the form of a Wheatstone bridge to form a bridge circuit unit. Electrically connect the power supply between the first node and the third node of the bridge circuit unit, electrically connect the acquisition unit between the second node and the fourth node of the bridge circuit unit, and electrically connect the acquisition unit, the computer, and the power supply in sequence.

[0007] 2) Cut the shock absorber to be tested along the sealing part of its cylinder block, record the strain signal throughout the process by computer, and obtain the strain value X0 of the shock absorber to be tested when cutting the seal. At this time, the pre-tightening force of the shock absorber to be tested is 0;

[0008] 3) Fix the shock absorber to be tested with the seal cut on the test bench, apply a load along the axial direction of the cut position to simulate the pre-tightening force F, gradually increase the pre-tightening force F, collect the strain signal X corresponding to the pre-tightening force F by the acquisition unit, and finally obtain the calibration relationship between the pre-tightening force and strain F = f(X) through computer processing and fitting;

[0009] 4) According to the calibration relationship between the pre-tightening force and strain F = f(X) obtained in step 3), when the strain X = 0, obtain the initial pre-tightening force F0 of the shock absorber to be tested.

[0010] As a preferred technical solution, in step 1), a plurality of strain sensors are pasted at different positions on the cylinder block to sense the strain at different positions on the cylinder block.

[0011] As a preferred technical solution, in step 3), substitute the strain value X0 of the shock absorber to be tested when the pre-tightening force F = 0 obtained in step 2) into F = f(X) for verification.

[0012] The beneficial effects of the present invention are as follows: Using strain sensors can conveniently and quickly detect the seal pre-tightening force of the shock absorber, providing data support for improving the seal quality of the shock absorber. And it lays a foundation for further research on other performances of the shock absorber. Description of the Drawings

[0013] Figure 1 It is the working flow chart of the pre-tightening force test system of the shock absorber of the present invention.

[0014] Figure 2 It is the structural schematic diagram of the shock absorber to be tested.

[0015] Figure 3 It is the structural schematic diagram of the bridge circuit unit.

[0016] Figure 4 It is the structural schematic diagram of applying a load along the axial direction of the cut position of the shock absorber to be tested.

[0017] Figure 5 It is the schematic diagram of the calibration relationship between the pre-tightening force and strain.

[0018] Description of the reference numerals: strain sensor 1, bridge circuit unit 2, first node 2a, second node 2b, third node 2c, fourth node 2d, acquisition unit 3, computer 4, power supply 5, shock absorber to be tested 6, cylinder block 6-1. Detailed Embodiments

[0019] The present invention will be described in detail below with reference to the accompanying drawings:

[0020] Embodiment: As shown in the Figures 1 to 3 accompanying drawings, a shock absorber pre-tightening force test system includes a strain sensor 1, a bridge unit 2, a collection unit 3, a computer 4, a power supply 5, and a shock absorber 6 to be tested. The strain sensor 1 is electrically connected to three resistors R1, R2, and R3 with the same resistance value in the form of a Wheatstone bridge as a branch arm to form the bridge unit 2. A power supply potential E is applied between the first node 2a and the third node 2c of the bridge unit 2. The power supply 5 is electrically connected between the first node 2a and the third node 2c to provide the power supply potential E. A measurement potential e0 is formed between the second node 2b and the fourth node 2d of the bridge unit 2. The collection unit 3 is electrically connected between the second node 2b and the fourth node 2d to collect the measurement potential e0. The computer 4 is electrically connected to the collection unit 3 to calculate the corresponding strain value according to the measurement potential e0 and display and record the strain signal. The power supply 5 is electrically connected to the computer 4 to achieve power supply. The strain sensor 1 is fixed on the cylinder block 6-1 of the shock absorber 6 to be tested to sense the strain of the cylinder block 6-1.

[0021] The test method using the above shock absorber pre-tightening force test system includes the following steps:

[0022] 1) Paste a plurality of strain sensors 1 at different positions on the cylinder block 6-1 of the shock absorber 6 to be tested. Then, electrically connect each strain sensor 1 to three resistors R1, R2, and R3 with the same resistance value in the form of a Wheatstone bridge to form the bridge unit 2. Electrically connect the power supply 5 between the first node 2a and the third node 2c of the bridge unit 2. Electrically connect the collection unit 3 between the second node 2b and the fourth node 2d of the bridge unit 2. Electrically connect the collection unit 3, the computer 4, and the power supply 5 in sequence.

[0023] 2) Cut the shock absorber 6 to be tested along the sealing opening of its cylinder block 6-1. Record the strain signal throughout the process by the computer 4 to obtain the strain value X0 of the shock absorber 6 to be tested when the sealing opening is cut. At this time, the pre-tightening force of the shock absorber 6 to be tested is 0.

[0024] 3) As shown in the Figure 4 accompanying drawings, fix the shock absorber 6 with the cut sealing opening on a test bench (which plays a role of support and fixation). Apply a load axially along the cut position of the cylinder block 6-1 to simulate the pre-tightening force F. Gradually increase the pre-tightening force F. The collection unit 3 collects the strain signal X corresponding to the pre-tightening force F. After being processed and fitted by the computer 4, the calibration relationship between the pre-tightening force and the strain F = f(X) is finally obtained. As shown in the Figure 5As shown in the figure, for the shock absorber 6 to be measured, the calibration relationship between its pre-tightening force and strain is: F = f(X) = -46.791X + 716.61; substitute the strain value X0 of the shock absorber 6 to be measured when the pre-tightening force F = 0 obtained in step 2) into F = -46.791X + 716.61 for verification;

[0025] 4) According to the calibration relationship F = f(X) of the pre-tightening force-strain obtained in step 3), when the strain X = 0, the initial pre-tightening force F0 of the shock absorber 6 to be measured is obtained, F0 = f(0) = 716.61.

[0026] The present invention uses a strain sensor (i.e., a resistance strain gauge) to convert the strain into an electrical parameter for testing. Since the strain sensor is pasted on the surface of the cylinder body of the shock absorber to be measured, the resistance of the strain sensor will change with the deformation of the cylinder body surface. Under the action of a Wheatstone bridge (i.e., a bridge circuit unit), a changing measured electric potential e0 will be generated, and the strain value of the shock absorber to be measured is obtained through computer conversion. At the same time, the form of an external load is used to simulate the pre-tightening force, and the calibration relationship between the pre-tightening force and the strain is fitted. Finally, the pre-tightening force at the sealing of the shock absorber to be measured is obtained, providing data support for improving the sealing quality of the shock absorber. And it lays a foundation for studying other performances of the shock absorber in the future..

[0027] It can be understood that for those skilled in the art, any equivalent substitution or change to the technical solution and inventive concept of the present invention should fall within the protection scope of the appended claims of the present invention.

Claims

1. A test method using a shock absorber pre-tightening force test system, characterized in that: The shock absorber pre-tightening force test system includes a strain sensor (1), a bridge circuit unit (2), an acquisition unit (3), a computer (4), a power supply (5), and a shock absorber to be tested (6). The strain sensor (1) is electrically connected to three resistors (R1, R2, R3) with the same resistance value in the form of a Wheatstone bridge to form the bridge circuit unit (2). A power supply potential E is applied between the first node (2a) and the third node (2c) of the bridge circuit unit (2). The power supply (5) is electrically connected between the first node (2a) and the third node (2c) to provide the power supply potential E. A measurement potential e0 is formed between the second node (2b) and the fourth node (2d) of the bridge circuit unit (2). The acquisition unit (3) is electrically connected between the second node (2b) and the fourth node (2d) to acquire the measurement potential e0. The computer (4) is electrically connected to the acquisition unit (3) to calculate the corresponding strain value based on the measurement potential e0 and display and record the strain signal. The power supply (5) is electrically connected to the computer (4) to achieve power supply. The strain sensor (1) is fixed on the cylinder block (6-1) of the shock absorber to be tested (6) to sense the strain of the cylinder block (6-1). The test method includes the following steps: 1) Paste the strain sensor (1) on the cylinder block (6-1) of the shock absorber to be tested (6), and then electrically connect the strain sensor (1) to three resistors (R1, R2, R3) with the same resistance value in the form of a Wheatstone bridge to form the bridge circuit unit (2). Electrically connect the power supply (5) between the first node (2a) and the third node (2c) of the bridge circuit unit (2), electrically connect the acquisition unit (3) between the second node (2b) and the fourth node (2d) of the bridge circuit unit (2), and electrically connect the acquisition unit (3), the computer (4), and the power supply (5) in sequence. 2) Cut open the shock absorber to be tested (6) along the sealing position of its cylinder block (6-1), and record the strain signal throughout the process by the computer (4) to obtain the strain value X0 of the shock absorber to be tested (6) when the sealing is cut open. At this time, the pre-tightening force of the shock absorber to be tested (6) is 0. 3) Fix the shock absorber to be tested (6) with the cut-open sealing on the test bench, apply a load along the axial direction of the cut position to simulate the pre-tightening force F, gradually increase the pre-tightening force F, collect the strain signal X corresponding to the pre-tightening force F by the acquisition unit (3), and finally obtain the calibration relationship F = f(X) of the pre-tightening force - strain through processing and fitting by the computer (4). 4) According to the calibration relationship F = f(X) of the pre-tightening force - strain obtained in step 3), when the strain X = 0, obtain the initial pre-tightening force F0 of the shock absorber to be tested (6).

2. The test method according to claim 1, characterized in that: In step 1), several strain sensors (1) are pasted at different positions on the cylinder block (6-1) to sense the strains at different positions on the cylinder block (6-1).

3. The testing method according to claim 1, characterized in that: In step 3), substitute the strain value X0 of the shock absorber to be tested (6) when the pre-tightening force F = 0 obtained in step 2) into F = f(X) for verification.

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