A NVH detection method for the offline reduction gearbox

Abstract

A method for off-line NVH detection of a speed reducer is as follows: 1) Formulate an off-line NVH detection outline for the speed reducer, clarify the order characteristics of the speed reducer, and determine the installation positions of vibration acceleration sensors according to the order characteristics; 2) Conduct an acceptance check on the stability of off-line NVH detection of the speed reducer; 3) Through self-learning of off-line detection analysis instruments, formulate off-line NVH detection standards for the speed reducer; 4) According to the off-line NVH detection standards for the speed reducer, conduct off-line detection on the speed reducer to be detected. If the detection results meet the detection standards, the speed reducer is qualified and can be shipped out. If the detection results do not meet the detection standards, proceed to step 5); 5) Install the speed reducer that does not meet the detection standards into the vehicle, and conduct subjective driving evaluation and objective analysis of test data.

Description

Technical Field

[0001] The present invention relates to the technical field of reducer detection, and particularly to a method for detecting the NVH of a reducer at the time of offline production. Background Art

[0002] With the development of new energy vehicles, new energy reducers have been widely used in new energy vehicles due to their advantages such as simple structure, low cost, and high transmission efficiency. The reducer of a new energy vehicle, as an important part of the vehicle's transmission system, can be composed of single-stage or two-stage gear transmissions, and both of these gear transmissions are integrated with a differential. The reducer reduces speed and increases torque by changing the vehicle's transmission ratio, improving the vehicle's power performance. The integrated differential can achieve differential rotation of the wheels, improving the vehicle's stability and handling performance.

[0003] The NVH problems of the reducer in the vehicle mainly include noise problems caused by gear whine and oil pump whine, as well as abnormal noises or other quality problems caused by gear knocking, improper assembly, and poor cleanliness. The offline detection of the reducer is an effective method for controlling the above problems. It can detect the product offline in a targeted and effective manner, monitor the product quality using a reliable and reasonable offline detection method, and also improve the market competitiveness and overall strength of the enterprise's products.

[0004] The existing detection of reducers usually relies on the method of manual listening to judge whether there are problems such as excessive whine or abnormal noise during the operation of the reducer. It is easy to have problems with manual judgment errors, which may easily lead to unqualified products being installed in vehicles and flowing into the market, affecting the riding comfort, and even causing safety accidents. Therefore, how to set a reasonable detection standard and how to ensure the accuracy of the detection results, so as to ensure that there are no NVH problems when the reducer is installed in the vehicle, and at the same time avoid excessive increase in manufacturing costs due to the detection standard, are the main problems faced by the current detection of new energy reducers. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for detecting the NVH of a reducer at the time of offline production in view of the deficiencies of the prior art, which can objectively evaluate the NVH performance of the reducer during the offline detection stage, effectively intercept unqualified products, and prevent unqualified reducers from flowing into the market.

[0006] The technical solution of the present invention is: a method for detecting the NVH of a reducer at the time of offline production, the steps are as follows:

[0007] 1) Formulate an NVH offline detection outline for the reducer, clarify the order characteristics of the reducer, and determine the installation positions of vibration acceleration sensors according to the order characteristics;

[0008] 2) Conduct an acceptance inspection on the stability of the NVH offline detection of the reducer to ensure the detection accuracy of the test bench;

[0009] 3) Formulate the NVH off-line inspection standard for the reducer through the self-learning of the off-line inspection analysis instrument;

[0010] 4) According to the NVH off-line inspection standard for the reducer, conduct off-line inspection on the reducer to be inspected. If the inspection result meets the inspection standard, the reducer is qualified and can leave the factory. If the inspection result does not meet the inspection standard, go to step 5);

[0011] 5) Install the reducer that does not meet the inspection standard into the whole vehicle, and judge whether the inspection result of the reducer is within the acceptable range through subjective driving evaluation and objective analysis of test data. If it is within the acceptable range, the reducer is qualified and can leave the factory. If not, repair the reducer and conduct off-line inspection on the repaired reducer again according to step 1).

[0012] Furthermore, the specific steps of formulating the NVH off-line inspection outline for the reducer in step 1) are as follows:

[0013] 1-1) Conduct bench and vehicle NVH tests on multiple reducer prototypes of the same model to determine the NVH characteristics of the reducer products of this model, and clarify the orders, speeds, and torques corresponding to obvious reducer characteristics;

[0014] 1-2) Determine the test conditions for the off-line inspection of the reducer according to the speeds and torques corresponding to obvious NVH characteristics of the reducer obtained in step 1-1);

[0015] 1-3) Install the vibration acceleration sensor for the off-line inspection of the reducer at a position that can reflect the NVH characteristics of the reducer, and adjust the press-fitting displacement of the vibration acceleration sensor as needed.

[0016] Furthermore, in step 2), the specific steps for the stability acceptance of the NVH off-line inspection of the reducer are as follows:

[0017] 2-1) Install different reducers of the same batch on the inspection bench and verify whether the inspection results of these reducers are within the error range;

[0018] 2-2) Repeatedly remove and install the reducer on the inspection bench for off-line inspection, and verify whether the inspection result of the reducer is within the error range;

[0019] 2-3) Repeatedly clamp the reducer on the inspection bench for off-line inspection, and verify whether the inspection result of the reducer is within the error range;

[0020] 2-4) Repeatedly press-fit the vibration acceleration sensor on the reducer for off-line inspection, and verify whether the inspection result is within the error range;

[0021] 2-5) Perform off-line inspection on the same reducer at different temperatures to verify whether the inspection results are within the error range.

[0022] Further, the value of the error range in the rotational speed section with obvious characteristics is smaller than that in the rotational speed section with unobvious characteristics.

[0023] Further, in step 3), the specific steps for formulating the off-line inspection standard for the reducer NVH are as follows:

[0024] 3-1) Select multiple reducers of different batches equipped with shaft gears for off-line inspection, and formulate the initial evaluation standard for the off-line inspection of the reducer through self-learning of the off-line analysis instrument;

[0025] 3-2) Select a small batch of reducers of different batches equipped with shaft gears for off-line inspection, and formulate the intermediate evaluation standard for the off-line inspection of the reducer through self-learning of the off-line analysis instrument;

[0026] 3-3) Select a large batch of reducers of different batches equipped with shaft gears for off-line inspection, and formulate the final evaluation standard for the off-line inspection of the reducer through self-learning of the off-line analysis instrument.

[0027] Further, the evaluation criteria for the initial, intermediate, and final stages include the sum of order lines, order slices of acceleration / deceleration, spikes, absolute value of quality index, relative value of quality index, time signal classification of quality standard, spike hold, and kurtosis.

[0028] Further, in step 4), the specific steps for performing off-line inspection on the reducer to be inspected are as follows:

[0029] 4-1) Before off-line inspection, first perform airtightness inspection on the reducer to be inspected, and check whether there are oil agents, dust, debris, and burrs on the surface of the reducer housing and at the pin holes;

[0030] 4-2) Push the reducer to be inspected onto the off-line inspection table for clamping and fixing, and start the inspection;

[0031] 4-3) Use the off-line detector to determine whether the reducer meets the off-line inspection standard. If it meets the standard, the reducer is qualified and can be shipped out. If it does not meet the standard, the reducer is unqualified and proceeds to step 5).

[0032] Beneficial effects of the above technical solution: Before the NVH inspection of the reducer is carried out offline, this method clarifies the working conditions and inspection standards required for the inspection of the reducer, formulates corresponding inspection standards for different inspection quantities of the reducer, ensures the accuracy of the inspection results, and through the stability acceptance of the NVH offline inspection of the reducer, ensures the inspection accuracy of the inspection equipment, avoiding errors in the inspection results caused by external inspection equipment. In addition, during the inspection process, this method fully considers evaluation criteria such as the sum of order lines, order slices of acceleration / deceleration, spikes, absolute value of quality index, relative value of quality index, time signal classification of quality standards, spike holding, kurtosis, etc., making the inspection results more comprehensive. Therefore, this method can objectively evaluate the NVH performance of the reducer during the offline inspection stage of the reducer, and combined with the actual situation of the vehicle, effectively intercept unqualified products.

[0033] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is the flowchart of the present invention;

[0035] Figure 2 is the NVH characteristic of a certain model reducer of the present invention;

[0036] Figure 3 is the inspection result of the stability acceptance of the present invention;

[0037] Figure 4 is the inspection result of the order slice of qualified products;

[0038] Figure 5 is the inspection result of the order slice of unqualified products;

[0039] Figure 6 is the inspection result of the spike holding of qualified products;

[0040] Figure 7 is the inspection result of the spike holding of unqualified products;

[0041] Figure 8 is the inspection result of the relative value of the quality index of qualified products;

[0042] Figure 9 is the inspection result of the relative value of the quality index of unqualified products;

[0043] Figure 10 is the inspection result of the kurtosis of qualified products;

[0044] Figure 11 is the inspection result of the kurtosis of unqualified products. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0045] SeeFigure 1 , a method for NVH detection of a reducer during off-line inspection, the steps are as follows:

[0046] 1) Formulate an NVH off-line inspection outline for the reducer, clarify the order characteristics of the reducer, and determine the installation positions of vibration acceleration sensors according to the order characteristics. The specific steps are as follows:

[0047] 1-1) Conduct bench and vehicle NVH tests on multiple prototypes of the same type of reducer to determine the NVH characteristics of the reducer products of this type, and clarify the orders, speeds, and torques corresponding to obvious reducer characteristics. For example, Figure 2 as shown, the detection data at obvious characteristics should be focused on in subsequent inspections;

[0048] 1-2) According to the speeds and torques corresponding to obvious NVH characteristics of the reducer obtained in step 1-1), determine the operating conditions to be tested for the off-line inspection of the reducer according to the corresponding relationship between speed and torque;

[0049] 1-3) Install the vibration acceleration sensors for the off-line inspection of the reducer at positions that can reflect the NVH characteristics of the reducer, and adjust the press-fitting displacement of the vibration acceleration sensors as needed. The press-fitting displacement is provided by the manufacturer as a reference value and is fine-tuned according to actual needs.

[0050] 2) Conduct an acceptance inspection on the stability of the NVH off-line inspection of the reducer to ensure the detection accuracy of the inspection bench;

[0051] 2-1) Install different reducers of the same model (i.e., the same batch) on the inspection bench to verify whether the detection results of these reducers are within the error range;

[0052] 2-2) Repeatedly remove and install the reducer installed on the inspection bench for off-line inspection to verify whether the detection results of this reducer are within the error range. The number of repetitions is usually 10 times;

[0053] 2-3) Repeatedly clamp the same reducer on the inspection bench for off-line inspection. The number of repetitions is usually 10 times to verify whether the detection results of this reducer are within the error range;

[0054] 2-4) Repeatedly press-fit the vibration acceleration sensors on the reducer for off-line inspection. The number of repetitions is usually 10 times to verify whether the detection results are within the error range;

[0055] 2-5) Conduct off-line inspection on the same reducer at different temperatures to verify whether the detection results are within the error range.

[0056] Among them, for the rotational speed segments with obvious characteristics, a smaller error range can be set. For example, the range between the maximum value and the minimum value is set to be less than 2 dB. For the rotational speed segments with unobvious characteristics, a larger error range can be set. For example, the range between the maximum value and the minimum value is set to be less than 10 dB, so as to ensure the accuracy of the detection results at the positions with obvious characteristics of the detection bench, as Figure 3 shown.

[0057] If the detection results of steps 2-1) and 2-2) are both within the error range, then steps 2-3), 2-4), and 2-5) do not need to be carried out anymore. Otherwise, the detections of steps 2-3), 2-4), and 2-5) need to be continued. Among them, the order between steps 2-3), 2-4), and 2-5) can be adjusted mutually. If the detection results of steps 2-3), 2-4), and 2-5) do not meet the error range, it is considered that there is a problem with the detection bench, and the detection bench needs to be deactivated to troubleshoot the reasons for the detection bench.

[0058] 3) Through the self-learning of the off-line detection analysis instrument, formulate the NVH off-line detection standard for the reducer;

[0059] 3-1) Select multiple reducers of different batches equipped with shaft gears for off-line detection. In this embodiment, 100 reducers are selected, and through the self-learning of the off-line analysis instrument, formulate the initial evaluation standard for the off-line detection of the reducer;

[0060] 3-2) Select a small batch of reducers of different batches equipped with shaft gears for off-line detection. The small batch in this embodiment is to select 500 reducers, and through the self-learning of the off-line analysis instrument, formulate the intermediate evaluation standard for the off-line detection of the reducer;

[0061] 3-3) Select a large batch of reducers of different batches equipped with shaft gears for off-line detection. The small batch in this embodiment is to select 1000 reducers, and through the self-learning of the off-line analysis instrument, formulate the final evaluation standard for the off-line detection of the reducer.

[0062] Since the main problems that the reducer does not meet the off-line detection standard include: meshing order howling such as the order of the first-stage gear pair and the order of the second-stage gear pair of the gears, defects and bumps of parts, abnormal noises caused by part defects and abnormalities, etc. Therefore, for the above problems, the evaluation standards proposed in this embodiment include: order line sum, order slice of speed increase / decrease, peak, absolute value of quality index QI, relative value of quality index QI / R, time signal classification of quality standard QI / C, peak hold, kurtosis. According to different models of reducers and the performance of the reducers in the whole vehicle, the indicators to be detected and the functions corresponding to each indicator are shown in Table 1.

[0063] Table 1 Off-line detection indicators of the reducer off-line detection bench

[0064]

[0065] 4) According to the NVH off-line inspection standard of the reducer, conduct off-line inspection on the reducer to be inspected;

[0066] 4-1) Before off-line inspection, first conduct airtightness inspection on the reducer to be inspected, and check whether there are oil agents, dust, debris, and burrs on the surface of the reducer housing and pin holes;

[0067] 4-2) Push the reducer to be inspected onto the off-line inspection table, clamp and fix it, and start the inspection;

[0068] 4-3) Use the off-line inspection instrument to judge whether the reducer meets the off-line inspection standard. If it meets the standard, the reducer is qualified and can leave the factory. If it does not meet the standard, the reducer is unqualified and enters step 5).

[0069] 5) Install the reducer that does not meet the inspection standard into the whole vehicle. Through subjective driving evaluation and objective analysis of test data, judge whether the inspection result of the reducer is within the acceptable range. If it is within the acceptable range, the reducer is qualified and can leave the factory, and optimize the off-line inspection evaluation standard according to the objective evaluation result of the driving evaluation of the reducer. If it is not within the acceptable range, repair the reducer, and re-conduct off-line inspection on the repaired reducer according to step 1).

[0070] The above method is used to conduct NVH off-line inspection on the reducer:

[0071] 1. Conduct order slicing on the characteristic orders of the reducer to detect the gear howling problem of the reducer. As Figure 4 shown, the detection curve of the order slice of the qualified reducer is within the range of the detection standard curve. As Figure 5 shown, the detection curve of the order slice of the unqualified reducer partially exceeds the range of the detection standard curve.

[0072] 2. Detect the spectrum line of the reducer through peak holding to identify abnormal orders such as low orders and ghost orders of the reducer. As Figure 6 shown, the order spectrum of the qualified product is within the range of the detection standard line. As Figure 7 shown, there are some orders in the order spectrum of the unqualified reducer that exceed the detection standard.

[0073] 3. Detect the relative value of the quality index of the reducer to identify the abnormal order situation of high amplitude. As Figure 8 shown, the relative value of the quality index of the qualified reducer is mostly within the detection standard range. As Figure 9 shown, the relative value of the quality index of the unqualified reducer almost all exceeds the detection standard.

[0074] 4. Detect the kurtosis of the reducer to identify abnormal noises caused by abnormalities such as knocking and hitting of gears. As Figure 10 shown, the kurtosis of qualified reducers is less than the detection standard. As Figure 11 shown, there are multiple kurtosis values of unqualified reducers that exceed the detection standard. Among them, technicians can determine the number of kurtosis values that exceed the detection standard according to the actual situation as the identification standard for unqualified products.

[0075] Before the offline NVH detection of the reducer, this method clarifies the working conditions and detection standards required for the reducer detection, formulates corresponding detection standards for different reducer detection quantities, ensures the accuracy of the detection results, and through the stability acceptance of the offline NVH detection of the reducer, ensures the detection accuracy of the detection equipment, avoiding errors in the detection results caused by external detection equipment. In addition, during the detection process, this method fully considers evaluation criteria such as the sum of order lines, order slices of acceleration / deceleration, spikes, absolute value of quality index, relative value of quality index, time signal classification of quality standard, spike holding, and kurtosis, making the detection results more comprehensive. Therefore, this method can objectively evaluate the NVH performance of the reducer during the offline detection stage of the reducer and effectively intercept unqualified products in combination with the actual situation of the whole vehicle.

Claims

1. A method for detecting NVH during the offline of a speed reducer, characterized in that The steps are as follows: 1) Formulate the NVH off-line inspection outline for the reducer, clarify the order characteristics of the reducer, and determine the installation positions of vibration acceleration sensors according to the order characteristics; 1-1) Conduct bench and vehicle NVH tests on multiple reducer prototypes of the same model to determine the NVH characteristics of the reducer products of this model, and clarify the orders, speeds, and torques corresponding to obvious reducer characteristics; 1-2) Determine the test conditions for the off-line inspection of the reducer based on the speeds and torques corresponding to obvious NVH characteristics of the reducer obtained in step 1-1); 1-3) Install the vibration acceleration sensors for the off-line inspection of the reducer at positions that can reflect the NVH characteristics of the reducer, and adjust the press-fitting displacement of the vibration acceleration sensors as needed; 2) Conduct stability acceptance for the NVH off-line inspection of the reducer to ensure the detection accuracy of the inspection bench; 2-1) Install different reducers of the same batch on the inspection bench to verify whether the detection results of these reducers are within the error range; 2-2) Repeatedly remove and install the reducer installed on the inspection bench for off-line inspection to verify whether the detection result of this reducer is within the error range; 2-3) Repeatedly clamp the reducer on the inspection bench for off-line inspection to verify whether the detection result of this reducer is within the error range; 2-4) Repeatedly press-fit the vibration acceleration sensors on the reducer for off-line inspection to verify whether the detection results are within the error range; 2-5) Conduct off-line inspection of the same reducer at different temperatures to verify whether the detection results are within the error range; 3) Formulate the NVH off-line inspection standard for the reducer through self-learning of the off-line inspection analysis instrument; 3-1) Select multiple reducers of different batches equipped with shaft gears for off-line inspection, and formulate the initial evaluation standard for the off-line inspection of the reducer through self-learning of the off-line analysis instrument; 3-2) Select a small batch of reducers of different batches equipped with shaft gears for off-line inspection, and formulate the intermediate evaluation standard for the off-line inspection of the reducer through self-learning of the off-line analysis instrument; 3-3) Select a large number of reducers of different batches equipped with shaft gears for off-line inspection, and formulate the final evaluation standard for the off-line inspection of the reducer through self-learning of the off-line analysis instrument; 4) Conduct off-line inspection of the reducer to be inspected according to the NVH off-line inspection standard for the reducer. If the inspection result meets the inspection standard, the reducer is qualified and can be shipped. If the inspection result does not meet the inspection standard, go to step 5); 5) Install the reducer that does not meet the inspection standard in the vehicle, and judge whether the inspection result of this reducer is within the acceptable range through subjective driving evaluation and objective analysis of test data. If it is within the acceptable range, the reducer is qualified and can be shipped. If not, repair the reducer and re-conduct the off-line inspection of the repaired reducer according to step 1).

2. The NVH detection method for the offline reduction gearbox according to claim 1, wherein: The value of the error range in the speed segment with obvious characteristics is less than the value in the speed segment with less obvious characteristics.

3. A NVH detection method for a reducer off-line according to claim 1, characterized in that: The evaluation criteria for the initial, intermediate, and final stages include the sum of order lines, order slices for acceleration / deceleration, spikes, absolute value of quality index, relative value of quality index, time signal classification of quality standard, spike holding, and kurtosis.

4. A method for detecting NVH during the offline process of a speed reducer, as claimed in claim 1, wherein In step 4), the specific steps for offline inspection of the reducer to be inspected are as follows: 4-1) Before offline inspection, first perform airtightness inspection on the reducer to be inspected, and check whether there is oil agent, dust, debris, and burrs on the surface of the reducer housing and the pin holes; 4-2) Push the reducer to be inspected onto the offline inspection table, clamp and fix it, and start the inspection; 4-3) Use the offline inspection instrument to determine whether the reducer meets the offline inspection standard. If it meets the standard, the reducer is qualified and can be shipped out. If it does not meet the standard, the reducer is unqualified and proceeds to step 5).

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