A Dynamic Engagement Noise Test System and Method for an Automotive Air Conditioning Compressor Clutch

Abstract

The present invention discloses an automotive air-conditioning compressor clutch dynamic engagement noise test system and method for testing and evaluating the engagement noise of an automotive compressor clutch under shaft load. The test system includes a motor drive platform and a compressor clutch to be tested. The compressor clutch has a pulley and an armature. An electromagnetic coil is provided inside the pulley of the compressor clutch to attract the armature of the compressor clutch. It also includes a rotating shaft bracket and a magnetic powder clutch. The rotating shaft bracket and the magnetic powder clutch are respectively fixedly installed on the motor drive platform. The pulley of the compressor clutch is installed on the rotating shaft bracket through a bearing. The motor of the motor drive platform is power-connected to the pulley of the compressor clutch through a belt. The rotating shaft of the magnetic powder clutch is rigidly connected to the armature of the compressor clutch, making the magnetic powder clutch an equivalent device for the shaft load of the compressor clutch. The test method includes: test conditions; test process; data processing.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive air-conditioning compressors, and particularly to a dynamic engagement noise test system and method for an automotive air-conditioning compressor clutch. Background Art

[0002] 1) The dynamic engagement noise of the clutch is one of the main sources of noise in automotive air-conditioning compressors. The dynamic engagement noise of the clutch in existing test experiments is achieved by simulating the suction noise of the compressor load. There is uncertainty in the change of the operating load conditions during the engagement and disengagement actions of the clutch, resulting in large fluctuations in the suction noise each time. The reason is that the existing dynamic engagement noise test method of the clutch mainly uses the shaft load conditions composed of the pressure, temperature, refrigerant volume, etc. of the compressor operation as the initial state of engagement. After multiple engagements, the shaft load state is different each time due to the change of the operating load, which cannot be accurately controlled, and then the result of the measured dynamic engagement noise fluctuates and cannot be accurately evaluated.

[0003] 2) The test method based on the dynamic engagement noise has relatively complex requirements for test samples. There are differences in different compressor installation methods and structures, which results in differences in quantitatively evaluating the noise of the compressor clutch.

[0004] 3) Under the original method of controlling the operating conditions and load of the compressor through the equipment system, after a single engagement and disengagement action, the time for the system to stabilize to the test conditions again is long, resulting in a long test time for the dynamic engagement noise. It is necessary to improve the test stability and test efficiency.

[0005] 4) The suction noise of the compressor belongs to an impact signal. It is crucial to determine when to trigger the measurement of the impact signal. An inappropriate trigger moment will cause the amplitude of the impact signal to decay or the measurement to be incomplete. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a dynamic engagement noise test system and method for an automotive air-conditioning compressor clutch, which is used to test and evaluate the engagement noise method of an automotive compressor clutch under shaft load.

[0007] The purpose of the present invention is achieved as follows:

[0008] An automotive air-conditioning compressor clutch dynamic engagement noise test system, comprising a motor drive platform and a compressor clutch to be tested. The compressor clutch has a pulley and an armature. An electromagnetic coil is provided inside the pulley of the compressor clutch for attracting the armature of the compressor clutch. It further includes a rotating shaft support and a magnetic powder clutch. The rotating shaft support and the magnetic powder clutch are respectively fixedly installed on the motor drive platform. The pulley of the compressor clutch is installed on the rotating shaft support through a bearing. The motor of the motor drive platform is power-connected to the pulley of the compressor clutch through a belt. The rotating shaft of the magnetic powder clutch is rigidly connected to the armature of the compressor clutch, making the magnetic powder clutch an equivalent device for the shaft load of the compressor clutch.

[0009] Preferably, the rotating shaft of the magnetic powder clutch is a spline shaft. The spline end of the rotating shaft of the magnetic powder clutch is in spline fit with the armature of the compressor clutch and locked with a nut, so that the rotating shaft part of the compressor clutch is replaced by the rotating shaft of the magnetic powder clutch, and the head cover part of the compressor clutch is replaced by the rotating shaft support.

[0010] Preferably, it further includes a microphone arranged corresponding to the pulley and the armature of the compressor clutch for collecting the dynamic engagement noise signal of the compressor clutch.

[0011] Preferably, it further includes a current sensor. The current sensor is connected in series with the electromagnetic coil of the compressor clutch for measuring the current signal of the electromagnetic coil of the compressor clutch.

[0012] An automotive air-conditioning compressor clutch dynamic engagement noise test method, using the test system. The test method includes the following steps:

[0013] S1. Test conditions

[0014] Convert the load under the actual working conditions of the compressor into an equivalent shaft torque. Control the torque applied to the rotating shaft of the magnetic powder clutch through the coil current of the magnetic powder clutch, and then control the shaft load of the compressor clutch, so that the shaft load of the compressor clutch is equal to the equivalent shaft torque, and pre-load the shaft load before the compressor clutch engages.

[0015] S2. Test process

[0016] Measure the engagement noise under the shaft load application. Convert the collected dynamic engagement noise signal of the compressor clutch into an electrical signal through the microphone, and calculate the noise decibel value.

[0017] And, simultaneously measure the current signal of the electromagnetic coil of the compressor clutch.

[0018] S3. Data processing

[0019] Perform an operation on the total noise value for the noise measurement data results obtained in the test process.

[0020] Preferably, in step S2, according to the electrical signal of the electromagnetic coil of the compressor clutch, determine the condition for triggering the microphone to collect the engaging noise; according to the duration required for the engaging process of the compressor clutch, obtain the duration for the microphone to collect the engaging noise.

[0021] Preferably, in step S3, draw the dynamic engaging noise curve of the compressor clutch and the electromagnetic coil current curve of the compressor clutch, and obtain the electromagnetic coil current change interval of the compressor clutch corresponding to the engaging noise collection interval;

[0022] According to the electromagnetic coil current change interval of the compressor clutch, determine the starting moment and the stopping moment of the noise total value operation.

[0023] Preferably, in step S1,

[0024] The supply voltage of the electromagnetic coil of the compressor clutch is selected as 12 VDC. During the test, the number of engagements is more than 10 times, and the duration after each single engagement is 5 - 10 seconds;

[0025] The microphone frequency response range is selected as 20 - 20000 Hz or above, the dynamic amplitude is 120 dB, and the position of the engaging noise measurement point is selected at a distance of 10 - 50 cm from the center axis of the clutch;

[0026] Connect the current sensor in series with the electromagnetic coil of the compressor clutch to measure the current signal of the electromagnetic coil of the compressor clutch; the signal conversion period of the current sensor is less than 1 ms, so as to respond to the current dynamic signal at the moment of engagement;

[0027] Preferably, a plurality of measurement points are evenly set circumferentially along the pulley of the compressor clutch. By measuring the magnitude difference of the engaging noise at each measurement point to judge whether the engaging forces at each engaging contact position on the circumference are consistent when the clutch engages. If the engaging forces are consistent, it is determined that the clutch sample is normally installed.

[0028] Preferably, in step S1, the method for converting the load under the actual working conditions of the compressor into an equivalent shaft torque is as follows: Before the test, run the compressor under various working condition loads on the performance test bench, and at the same time, use the compressor dynamic torque measuring device to measure the shaft torque of the compressor in real time. The measured torque value will represent the load magnitude of the compressor operation.

[0029] Due to the adoption of the above technical solutions, the present invention solves the following problems:

[0030] 1) Solve the problem that the dynamic engaging noise fluctuates due to the shaft load fluctuation during multiple dynamic engagements of the automotive air - conditioner compressor, and ensure the stability of the engaging performance test evaluation under the dynamic load of the electromagnetic clutch.

[0031] 2) The present invention solves the problem of inaccurate triggering measurement timing of the suction noise signal during the dynamic suction process.

[0032] The present invention has the following beneficial effects:

[0033] 1. Ensure the standardized test standards for evaluating the suction noise of the compressor clutch and the dynamic suction noise, which is beneficial to the suction performance evaluation and performance control of the clutch product.

[0034] 2. It can be generalized to the suction noise tests of various forms of clutches, with universality.

[0035] 3. Improve the resource occupancy of the dynamic suction noise experimental test equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the cooperation of the compressor clutch and the magnetic powder clutch;

[0037] Figure 2 It is a schematic diagram of the system structure of the present invention;

[0038] Figure 3 It is a schematic diagram of the method flow of the present invention;

[0039] Figure 4 It is a schematic diagram of the dynamic suction noise curve of the compressor clutch and the electromagnetic coil current curve of the compressor clutch;

[0040] Figure 5 It is a schematic diagram of the microphone distribution.

[0041] In the figure, 1 is the motor drive table, 2 is the compressor clutch, 21 is the pulley, 22 is the armature, 23 is the electromagnetic coil, 24 is the bearing, 25 is the shaft seal, 3 is the magnetic powder clutch, 31 is the rotating shaft, 4 is the rotating shaft bracket, and 5 is the microphone. DETAILED DESCRIPTION OF THE INVENTION

[0042] Refer to Figure 1 、 Figure 2 , a dynamic suction noise test system for an automotive air-conditioning compressor clutch, including a motor drive table 1 and a compressor clutch 2 to be tested. The compressor clutch has a pulley 21 and an armature 22. An electromagnetic coil 23 is provided inside the pulley of the compressor clutch to attract the armature of the compressor clutch. It also includes a rotating shaft bracket 4 and a magnetic powder clutch 3. The rotating shaft bracket and the magnetic powder clutch are respectively fixedly installed on the motor drive table. The pulley of the compressor clutch is installed on the rotating shaft bracket through a bearing 24. The motor of the motor drive table is power-connected to the pulley of the compressor clutch through a belt. The rotating shaft 31 of the magnetic powder clutch is rigidly connected to the armature of the compressor clutch, making the magnetic powder clutch an equivalent device for the shaft load of the compressor clutch.

[0043] The rotating shaft of the magnetic powder clutch is a spline shaft. The spline end of the rotating shaft of the magnetic powder clutch is in spline fit with the armature of the compressor clutch and locked with a nut, so that the rotating shaft part of the compressor clutch is replaced by the rotating shaft of the magnetic powder clutch, and the head cover part of the compressor clutch is replaced by the rotating shaft bracket.

[0044] The test system also includes a microphone, which is arranged corresponding to the pulley and the armature of the compressor clutch and is used to collect the dynamic engagement noise signal of the compressor clutch.

[0045] The test system also includes a current sensor, which is connected in series with the electromagnetic coil of the compressor clutch and is used to measure the current signal of the electromagnetic coil of the compressor clutch.

[0046] Participate Figure 3 , a method for testing the dynamic engagement noise of an automotive air-conditioning compressor clutch, is divided into the following test links:

[0047] 1. Compressor shaft load condition

[0048] The dynamic engagement noise shaft load condition is converted according to the load condition under the actual working conditions of the compressor into an equivalent shaft torque, and preloaded before the clutch engages. It is recommended that the preloaded shaft torque of automotive air-conditioning compressors with a displacement of 60 cc to 150 cc be selected between 10 N·m and 40 N·m.

[0049] 2. Test conditions

[0050] Engagement condition: In the test conditions, the supply voltage of the clutch coil is selected as 12 VDC, the number of engagements is more than 10 times, and the engagement duration is selected according to 5 to 10 seconds.

[0051] Microphone condition: The frequency response range of the microphone is selected above 20 to 20,000 Hz, the dynamic amplitude is 120 dB, and the measurement point position of the engagement noise is selected at 30 cm axially from the center of the clutch for measurement. See Figure 2 .

[0052] The initial judgment of the engagement noise has 3 positions as the measurement points at 30 cm in the circumferential direction of the clutch. See Figure 5 .

[0053] Clutch current signal condition: Select a current sensor to be connected in series into the clutch coil circuit for measurement. The signal conversion period of the current sensor is less than 1 ms so as to be able to respond to the current dynamic signal at the moment of engagement.

[0054] 3. Test steps:

[0055] When at the measurement point position 1, by default, this is the initial position in the circumferential direction of the clutch, and perform multiple measurements of the engagement noise under the shaft load.

[0056] When the measuring point is at position 2, the position of the microphone sensor remains unchanged. After disengaging the armature, the armature rotates 120 degrees clockwise along the circumference and then the second multi - suction noise measurement is carried out.

[0057] When the measuring point is at position 3, the position of the microphone sensor remains unchanged. After disengaging the armature, the armature rotates another 120 degrees clockwise along the circumference and then the third multi - suction noise measurement is carried out.

[0058] As Figure 5 , it is recommended to set 3 noise measurement points as shown in the figure, mainly for the preliminary judgment and confirmation of the clutch suction noise. The function of setting multiple measuring points circumferentially is to judge whether the suction forces at each suction contact position on the circumference are consistent when the clutch suctions by measuring the magnitude and time - interval differences of the suction noise results. Because the difference in suction force will lead to the difference in the amplitude of the suction noise, the noise difference information at the measuring point positions can be used to judge whether the installation of the clutch sample is abnormal and whether there are unstable conditions such as double - clicking, which will affect the stable test evaluation of the clutch suction noise.

[0059] After the preliminary judgment and confirmation of the above clutch suction process, enter the formal test step. Generally, the position of the test microphone sensor is set at a position 10 - 50 cm away from the center of the clutch. Fix a certain rivet in the clutch armature at the same position and conduct more than 10 dynamic suction noise measurements. Then, average the noise amplitude results of multiple measurements to achieve the purpose of stable testing and characterizing the suction performance of the compressor clutch.

[0060] 4. Dynamic suction noise data processing:

[0061] According to the data results of the above - mentioned test process, the software is used to calculate the total noise value of the suction noise data, and the starting moment of calculating the noise is triggered according to the collected clutch current signal during the operation.

[0062] Among the above four parts, the test conditions in the first part are the main inventive points. First, in the present invention, a magnetic powder clutch is used as a quantitative shaft load equivalent device, the pre - load torque of the rotating shaft is used to replace the actual shaft load of the automotive air - conditioning compressor, and the loading torque on the rotating shaft of the magnetic powder clutch is accurately controlled by the magnitude of the current in the magnetic powder clutch coil. Then, the rotating shaft of the magnetic powder clutch is rigidly connected to the compressor clutch, replacing the original test conditions of the shaft load controlled by the operating conditions of the compressor.

[0063] Meanwhile, a rotating shaft bracket for installing and fixing the compressor pulley bearing is designed to ensure that the rotating shaft bracket can be installed on the motor drive platform. The rotating shaft bracket and the magnetic particle clutch are respectively installed and fixed on the motor drive platform. The compressor clutch pulley is driven by the motor to rotate at a certain speed. One end of the rotating shaft of the magnetic particle clutch, which simulates the shaft load of the compressor, is designed as a spline tooth shaft that mates with the spline of the armature of the compressor clutch, so that the rotating shaft and the head cover part of the compressor clutch are replaced by the rotating shaft of the magnetic particle clutch and the rotating shaft bracket. See the illustration Figure 1 。

[0064] Secondly, in the four parts of the present invention, the clutch coil current in the test conditions is used as the reference signal source for triggering the test at the moment of suction. The working principle of the electromagnetic clutch is to energize the electromagnetic coil inside the clutch, and the coil current generates an axial electromagnetic force, thereby attracting the suction surface of the armature to the suction surface of the pulley, resulting in a suction noise. When there is an axial load, the principle is the same. Through the formula:

[0065] F = NI, where F is the electromagnetic force, N is the number of turns of the coil, and I is the current in the coil.

[0066] The electromagnetic force generates an acceleration of the armature attracting towards the pulley suction surface. After the impact collision, it excites the vibration of the surrounding structural metal, and then generates vibration in the surrounding air medium, forming sound waves. The sound waves are radiated and transmitted in all directions in the form of sound pressure signals, and finally the sound pressure sensing diaphragm of the microphone senses the vibration and converts it into an electrical signal, and the noise decibel value is calculated.

[0067] F(τ) = NI(τ) → ma(τ) → m 1 a(τ)H(τ) → P(τ);

[0068] F(τ) is the function of the electromagnetic force with respect to time;

[0069] a(τ) is the function of the acceleration of the suction disc during the suction impact with respect to time;

[0070] H(τ) is the structural response transfer function of the vibration of the clutch metal components caused by the impact with respect to time;

[0071] P(τ) is the function of the air sound pressure wave with respect to time;

[0072] m is the mass of the suction disc;

[0073] m 1 is the mass of the suction disc and other components of the clutch;

[0074] The above chronological relationship between the current signal and the suction noise sound pressure signal before and after the trigger simulation time is shown in the illustration Figure 4 。

[0075] From the above process analysis, selecting the current as the trigger for measuring the closing noise can cover the acoustic energy radiation process during closing. Selecting the current signal (such as I = 0.5A, or other smaller currents) as the condition for triggering the acquisition of the closing noise, and then only need to select the closing time, which can be used as the calculation time for the amplitude of the closing noise. The present invention will, through the time analysis of the closing process, often select 10ms to 50ms as the duration for calculating the closing noise.

[0076] The initial transmission in this process starts with an electrical signal transmission. Therefore, selecting the current signal as the trigger moment signal can accurately capture the impact signal process of the closing noise. Unifying the trigger calculation time for the closing noise in this way will ensure the integrity of the closing noise test.

[0077] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A method for testing the dynamic engagement noise of an automotive air-conditioning compressor clutch, characterized in that, a test system is adopted, and the test system includes a motor drive platform and the compressor clutch to be tested. The compressor clutch has a pulley and an armature. An electromagnetic coil is provided inside the pulley of the compressor clutch for attracting the armature of the compressor clutch. It is characterized in that: it further includes a rotating shaft bracket and a magnetic powder clutch. The rotating shaft bracket and the magnetic powder clutch are respectively fixedly installed on the motor drive platform. The pulley of the compressor clutch is installed on the rotating shaft bracket through a bearing. The motor of the motor drive platform is power-connected to the pulley of the compressor clutch through a belt. The rotating shaft of the magnetic powder clutch is rigidly connected to the armature of the compressor clutch, making the magnetic powder clutch an equivalent device for the shaft load of the compressor clutch; the rotating shaft of the magnetic powder clutch is a spline tooth shaft. The spline end of the rotating shaft of the magnetic powder clutch is in spline fit with the armature of the compressor clutch and is locked with a nut, so that the rotating shaft part of the compressor clutch is replaced by the rotating shaft of the magnetic powder clutch, and the head cover part of the compressor clutch is replaced by the rotating shaft bracket; it further includes a microphone, which is arranged corresponding to the pulley and the armature of the compressor clutch for collecting the dynamic engagement noise signal of the compressor clutch; it further includes a current sensor, and the current sensor is connected in series with the electromagnetic coil of the compressor clutch for measuring the current signal of the electromagnetic coil of the compressor clutch; the test method includes the following steps: S1. Test conditions Convert the load under the actual working conditions of the compressor into an equivalent shaft torque. Control the torque applied to the rotating shaft of the magnetic powder clutch through the coil current of the magnetic powder clutch, and then control the shaft load of the compressor clutch, so that the shaft load of the compressor clutch is equal to the equivalent shaft torque, and pre-load the shaft load before the compressor clutch engages; S2. Test process Measure the engagement noise under the shaft load. Convert the dynamic engagement noise signal of the compressor clutch collected by the microphone into an electrical signal, and calculate the noise decibel value; and, simultaneously measure the current signal of the electromagnetic coil of the compressor clutch; S3. Data processing Perform an operation on the total noise value of the noise measurement data results obtained in the test process.

2. The method for testing the dynamic engagement noise of an automotive air-conditioning compressor clutch according to claim 1, characterized in that: in step S2, according to the electrical signal of the electromagnetic coil of the compressor clutch, determine the condition for triggering the microphone to collect the engagement noise; according to the duration required for the engagement process of the compressor clutch, obtain the duration for the microphone to collect the engagement noise.

3. The method for testing the dynamic engagement noise of an automotive air-conditioning compressor clutch according to claim 2, characterized in that: in step S3, draw the dynamic engagement noise curve of the compressor clutch and the current curve of the electromagnetic coil of the compressor clutch, and obtain the current change interval of the electromagnetic coil of the compressor clutch corresponding to the engagement noise collection interval; According to the current change interval of the electromagnetic coil of the compressor clutch, determine the start time and stop time of the total noise value operation.

4. The method for testing the dynamic engagement noise of an automotive air-conditioning compressor clutch according to claim 1, characterized in that: in step S1, Power supply to the electromagnetic coil of the compressor clutch is connected to the clutch coil terminal, and the terminal voltage is selected as 12 VDC. During the test, the number of engagements is more than 10 times, and the duration of each engagement is maintained for 5 - 10 seconds; The microphone frequency response range is selected above 20 - 20000 Hz, the dynamic amplitude is 120 dB, and the measurement point position of the engagement noise is selected at a distance of 10 - 50 cm from the center axis of the clutch; A current sensor is connected in series with the electromagnetic coil of the compressor clutch to measure the current signal of the electromagnetic coil of the compressor clutch; the signal conversion period of the current sensor is less than 1 ms so as to be able to respond to the current dynamic signal at the moment of engagement.

5. A method for testing the dynamic engagement noise of an automotive air-conditioning compressor clutch according to claim 1, characterized in that: A plurality of measurement points are uniformly set along the circumference of the pulley of the compressor clutch. By measuring the magnitude difference of the engagement noise at each measurement point, it is judged whether the engagement forces at each engagement contact position on the circumference are consistent when the clutch engages. If the engagement forces are consistent, it is determined that the clutch sample is installed normally.

6. A method for testing the dynamic engagement noise of an automotive air-conditioning compressor clutch according to claim 1, characterized in that: In step S1, the method for converting the load under the actual working conditions of the compressor into an equivalent shaft torque is as follows: Before the test, the compressor is operated under various working condition loads on the performance test bench, and at the same time, the shaft torque of the compressor is measured in real time by a compressor dynamic torque measuring device. The torque value measured in this way will represent the magnitude of the load during the operation of the compressor.

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