A method and system for testing lubrication of an electrically driven reduction gearbox

Abstract

A kind of electric drive reduction gearbox lubrication test method and system, belong to electric drive reduction gearbox development technical field, including according to the preset vehicle parameter and electric drive parameter, the working condition characteristic parameter and / or the maximum speed of differential wheel end in reduction gearbox under multiple lubrication test working conditions is obtained by calculation;For each lubrication test working condition, multiple different test samples are generated;Each test sample includes oiling amount parameter, working condition characteristic parameter and differential wheel end speed;According to each test sample, carry out lubrication test, and collect real-time image of each bearing in reduction gearbox during testing to obtain the ratio of lubricating oil area and bearing total area and the corresponding test result by image recognition.This application calculates various lubrication test working condition related sample data through vehicle parameter and electric drive parameter, to generate lubrication test sample under all working conditions scientifically and comprehensively, and the test result is analyzed by image recognition, to improve evaluation accuracy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric drive reduction gearbox development, and particularly relates to a lubrication test method and system for an electric drive reduction gearbox. BACKGROUND

[0002] With the development of the automobile industry, more and more vehicle models begin to switch the powertrain from traditional fuel drive to electric drive. The normal operation and reliability of electric drive cannot be achieved without good lubrication. How to determine the minimum oiling amount of the reduction gearbox while ensuring that each component of the reduction gearbox has good lubrication effect under various working conditions is the key to the development of the oil of the reduction gearbox.

[0003] Therefore, the lubrication test of the reduction gearbox system is the basis for oil amount confirmation and subsequent test development. The existing related technology is only limited to improving the tooling structure in the lubrication test of the reduction gearbox, for example, improving the design of the lubricating oil passage in the reduction gearbox. The generation method of the lubrication working condition and the evaluation method of the test result lack systematic definition and detailed description, and it is difficult to associate with the actual use of the vehicle and the electric drive system (referred to as electric drive), and it is difficult to truly simulate the working condition of the reduction gearbox in actual driving.

[0004] Specifically, the generation of the existing lubrication working condition is mostly based on project experience and has certain randomness, and the existing evaluation method relies on manual visual inspection and is evaluated according to subjective evaluation, which is easy to ignore the related data in the lubrication process, resulting in low reliability of the lubrication effect evaluation result. SUMMARY

[0005] The present application provides a lubrication test method and system for an electric drive reduction gearbox, which can solve the technical problems of low lubrication test efficiency and inaccurate results in the prior art.

[0006] In a first aspect, an embodiment of the present application provides a lubrication test method for an electric drive reduction gearbox, the method comprising:

[0007] According to the preset vehicle parameters and electric drive parameters, working condition characteristic parameters and / or the maximum wheel end speed of the differential in a plurality of lubrication test working conditions are obtained; the plurality of lubrication test working conditions include flat ground driving working condition, slope driving working condition, acceleration and deceleration driving working condition, side leaning driving working condition, and slope and side leaning combined driving working condition, and the working condition characteristic parameters are used to describe the characteristics of the lubrication test working condition;

[0008] For each lubrication test working condition, a plurality of different test samples are generated; each test sample includes an oiling amount parameter, a working condition characteristic parameter, and a differential wheel end speed;

[0009] According to each test sample, the lubrication test of the reduction gearbox on the test bench is carried out respectively, and real-time images at each bearing in the reduction gearbox are collected during the test; image recognition is performed on the real-time images to obtain a ratio of a lubricating oil area to a total bearing area, and the lubrication result is quantitatively evaluated according to the ratio.

[0010] With reference to the first aspect, in an implementation, the method comprises:

[0011] For the flat ground driving condition, the highest forward speed of the vehicle when driving forward and the highest backward speed of the vehicle when driving backward are obtained by calculation according to the vehicle parameters and the electric drive parameters;

[0012] The maximum wheel end speed of the differential when the vehicle drives forward is obtained by calculation according to the highest forward speed, and the maximum wheel end speed of the differential when the vehicle drives backward is obtained by calculation according to the highest backward speed;

[0013] Different oiling amount parameters, different working condition characteristic parameters, and different differential wheel end speeds are combined to obtain a plurality of different test samples under the flat ground driving condition; the working condition characteristic parameters of the flat ground driving condition are used to describe the vehicle driving forward and the vehicle driving backward.

[0014] With reference to the first aspect, in an implementation, the highest forward speed is obtained by calculation according to the following formula:

[0015]

[0016] wherein,

[0017] P m represents the driving motor working condition demand, and the unit is kw;

[0018] V max1 represents the highest forward speed, and the unit is km / h;

[0019] η t represents the transmission system efficiency;

[0020] m represents the vehicle mass, and the unit is kg;

[0021] g represents the gravitational acceleration, g=9.8m / s 2 ;

[0022] f represents the vehicle rolling resistance coefficient;

[0023] C D represents the wind resistance coefficient;

[0024] A represents the windward area, and the unit is m 2 ;

[0025] m, g, f, C D, and A is a whole vehicle parameter, P m and η t is an electric drive parameter.

[0026] In combination with the first aspect, in an implementation, the maximum wheel end speed of the differential when the vehicle is moving forward is calculated using the following formula:

[0027]

[0028] wherein,

[0029] n dri represents the maximum wheel end speed of the differential when the vehicle is moving forward, in units of r / min;

[0030] V max1 represents the maximum forward speed, in units of km / h;

[0031] r represents the wheel diameter, in units of m.

[0032] The maximum wheel end speed of the differential when the vehicle is moving backward is calculated using the following formula:

[0033]

[0034] wherein,

[0035] n rev represents the maximum wheel end speed of the differential when the vehicle is moving backward, in units of r / min;

[0036] V max2 represents the maximum backward speed, in units of km / h;

[0037] r represents the wheel diameter, in units of m.

[0038] In combination with the first aspect, in an implementation, the method comprises:

[0039] For a hill driving condition, the maximum climbing degree when the vehicle is climbing a hill and the maximum descending degree when the vehicle is descending a hill are calculated according to the whole vehicle parameter and the electric drive parameter;

[0040] The maximum wheel end speed of the differential when the vehicle is climbing a hill and the maximum wheel end speed of the differential when the vehicle is descending a hill are calculated according to the preset coefficient and the maximum wheel end speed of the differential when the vehicle is moving forward;

[0041] Different fueling parameters, different condition characteristic parameters, and different differential wheel end speeds are combined to obtain a plurality of different test samples under the hill driving condition; the condition characteristic parameter of the hill driving condition is used to describe the climbing degree of the vehicle climbing a hill and the descending degree of the vehicle descending a hill.

[0042] With reference to the first aspect, in an embodiment, the method comprises:

[0043] For the acceleration and deceleration driving condition, the maximum acceleration liquid surface inclination in the reduction gearbox when the vehicle accelerates and the maximum deceleration liquid surface inclination in the reduction gearbox when the vehicle decelerates are calculated according to the vehicle parameters and the electric drive parameters;

[0044] The maximum wheel end speed of the differential when the vehicle accelerates is calculated according to the wheel speed at the inflection point of the external characteristic curve and the speed ratio of the reduction gearbox, to obtain the maximum wheel end speed of the differential when the vehicle accelerates;

[0045] The maximum wheel end speed of the differential when the vehicle accelerates is taken as the maximum wheel end speed of the differential when the vehicle decelerates;

[0046] Different oiling amount parameters, different condition characteristic parameters, and different differential wheel end speeds are combined to obtain a plurality of different test samples under the acceleration and deceleration driving condition; the condition characteristic parameters of the acceleration and deceleration driving condition are used to describe the maximum acceleration liquid surface inclination in the reduction gearbox when the vehicle accelerates and the maximum deceleration liquid surface inclination in the reduction gearbox when the vehicle decelerates.

[0047] With reference to the first aspect, in an embodiment, the method comprises:

[0048] For the side inclination driving condition, the maximum left inclination inclination in the reduction gearbox when the vehicle leans left and the maximum right inclination inclination in the reduction gearbox when the vehicle leans right are calculated according to the vehicle parameters and the electric drive parameters;

[0049] The maximum wheel end speed of the differential when the vehicle leans left and the maximum wheel end speed of the differential when the vehicle leans right are calculated according to the preset coefficient and the maximum wheel end speed of the differential when the vehicle accelerates;

[0050] Different oiling amount parameters, different condition characteristic parameters, and different differential wheel end speeds are combined to obtain a plurality of different test samples under the side inclination driving condition; the condition characteristic parameters of the side inclination driving condition are used to describe the left inclination inclination when the vehicle leans left and the right inclination inclination when the vehicle leans right.

[0051] With reference to the first aspect, in an embodiment, the method comprises:

[0052] For the combination of the slope and the side inclination driving condition, the test samples of the slope driving condition and the test samples of the side inclination driving condition are combined to obtain the test samples of the combination of the slope and the side inclination driving condition; the condition characteristic parameters of the combination of the slope and the side inclination driving condition are used to describe the slope degree when the vehicle climbs, the slope degree when the vehicle descends, the left inclination inclination when the vehicle leans left, and the right inclination inclination when the vehicle leans right.

[0053] With reference to the first aspect, in an embodiment, the method comprises:

[0054] After the reduction gearbox is installed to the test bench, the differential in the reduction gearbox is driven to rotate by a tool shaft of the test bench, the rotating speed of the tool shaft is consistent with the wheel end rotating speed of the differential in the test sample, and the position and action of the test bench are consistent with the oiling amount parameter and the working condition characteristic parameter in the test sample.

[0055] In a second aspect, the embodiments of the present application provide a lubrication test system for electric drive reduction gearbox, the system comprises:

[0056] The preprocessing module is configured to calculate the working condition characteristic parameters and / or the maximum wheel end rotating speed of the differential in the reduction gearbox under a plurality of lubrication test working conditions according to the preset vehicle parameters and electric drive parameters; the plurality of lubrication test working conditions comprise a flat road driving condition, a slope driving condition, an acceleration and deceleration driving condition, a side leaning driving condition, and a slope and side leaning combined driving condition, and the working condition characteristic parameters are used to describe the characteristics of the lubrication test working conditions;

[0057] The sample generation module is configured to generate a plurality of different test samples for each lubrication test working condition; each test sample comprises an oiling amount parameter, a working condition characteristic parameter, and a differential wheel end rotating speed;

[0058] The test module is configured to lubricate the reduction gearbox on the test bench according to each test sample respectively, and collect real-time images of each bearing in the reduction gearbox during the test; the real-time images are subjected to image recognition to obtain the ratio of the lubricating oil area to the total bearing area, and the lubrication result is quantitatively evaluated according to the ratio.

[0059] The technical scheme provided by the embodiments of the present application has the following beneficial effects:

[0060] The lubrication test samples under various lubrication test working conditions are generated by calculation considering the vehicle parameters and electric drive parameters, the oiling amount parameter, the working condition characteristic parameter, and the differential wheel end rotating speed are included in different lubrication test samples, the real driving scene can be scientifically and comprehensively simulated, and the comprehensiveness and accuracy of the lubrication test of the reduction gearbox are improved.

[0061] The real-time images of each bearing in the reduction gearbox are collected during the test, the real-time images are subjected to image recognition to obtain the ratio of the lubricating oil area to the total bearing area, and the test result is obtained according to the ratio, so that the objectivity and accuracy of the test evaluation result are improved in a quantitative evaluation manner. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 The flowchart of an embodiment of the lubrication test method for electric drive reduction gearbox of the present application;

[0063] Figure 2A flowchart of an embodiment of the lubrication test method for the electric drive reduction gearbox according to the present application;

[0064] Figure 3 A functional module diagram of an embodiment of the lubrication test system for the electric drive reduction gearbox according to the present application. DETAILED DESCRIPTION

[0065] In order to enable persons skilled in the art to better understand the scheme of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by persons skilled in the art without creative labor fall within the scope of protection of the present application.

[0066] In order to make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application will be described in further detail below with reference to the drawings.

[0067] In a first aspect, the embodiments of the present application provide a lubrication test method for an electric drive reduction gearbox.

[0068] In an embodiment, the lubrication test method for the electric drive reduction gearbox according to the present application comprises the following steps. Figure 1 and Figure 2 , Figure 1 A flowchart of an embodiment of the lubrication test method for the electric drive reduction gearbox according to the present application, Figure 2 A flowchart of an embodiment of the lubrication test method for the electric drive reduction gearbox according to the present application. As shown in Figure 1 and Figure 2 The lubrication test method for the electric drive reduction gearbox according to the present application comprises the following steps.

[0069] Step S1, calculating according to preset whole vehicle parameters and electric drive parameters to obtain working condition characteristic parameters in multiple lubrication test working conditions and / or maximum wheel end speed of a differential in the reduction gearbox. The multiple lubrication test working conditions comprise a flat ground driving working condition, a slope driving working condition, an acceleration and deceleration driving working condition, a side leaning driving working condition, and a slope and side leaning combined driving working condition, and the working condition characteristic parameters are used to describe the characteristics of the lubrication test working conditions.

[0070] Step S2, generating multiple different test samples for each lubrication test working condition. Each test sample comprises an oiling amount parameter, a working condition characteristic parameter, and a differential wheel end speed.

[0071] Step S3, lubricating the reduction gearbox on the test bench according to each test sample respectively, and collecting real-time images of each bearing in the reduction gearbox during the test.

[0072] Step S4, image recognition is performed on the real-time image to obtain a ratio of the lubricating oil area to the total bearing area, and the lubricating result is quantitatively evaluated according to the ratio.

[0073] In the prior art, the actual lubricating effect of the lubricating oil in the reduction gearbox is not accurately evaluated, and subjective evaluation is excessively relied on, resulting in a low evaluation quality. Moreover, in the actual driving process of the vehicle, uphill and downhill, acceleration and deceleration, left and right tilting, and the combination of uphill and downhill and left and right tilting all affect the actual lubricating effect, and the existing lubricating test lacks improvement on the lubricating condition.

[0074] In the embodiment, for the generation and evaluation of the lubricating test condition, the vehicle parameters and the electric drive parameters are considered, and the lubricating test samples under various lubricating test conditions are generated by calculation, and the oiling amount parameter, the condition characteristic parameter, and the differential wheel end speed are included in different lubricating test samples, so that the real driving scene can be scientifically and comprehensively simulated, and the comprehensiveness and accuracy of the lubricating test of the reduction gearbox are improved.

[0075] In the test process, real-time images of the bearings in the reduction gearbox are collected, image recognition is performed on the real-time images to obtain a ratio of the lubricating oil area to the total bearing area, the test result is obtained according to the ratio, and the objectivity and accuracy of the test evaluation result are improved in a quantitative evaluation manner.

[0076] Further, in an embodiment, the method comprises:

[0077] For the flat ground driving condition, the highest forward vehicle speed when the vehicle is moving forward and the highest backward vehicle speed when the vehicle is moving backward are obtained according to the vehicle parameters and the electric drive parameters.

[0078] The maximum wheel end speed of the differential when the vehicle is moving forward is obtained according to the highest forward vehicle speed, and the maximum wheel end speed of the differential when the vehicle is moving backward is obtained according to the highest backward vehicle speed.

[0079] Different oiling amount parameters, different condition characteristic parameters, and different differential wheel end speeds are combined to obtain a plurality of different test samples under the flat ground driving condition. The condition characteristic parameter of the flat ground driving condition is used to describe the vehicle moving forward and the vehicle moving backward.

[0080] In the embodiment, the flat ground driving condition is the basis of the lubricating test, and is generally tested and evaluated first. The lubricating performance of the reduction gearbox under the flat ground driving condition mainly depends on the differential wheel end speed corresponding to the highest vehicle speed when the vehicle is moving forward, and the differential wheel end speed corresponding to the highest vehicle speed when the vehicle is moving backward.

[0081] Further, in an embodiment, the highest forward vehicle speed is obtained by using the following formula (1):

[0082]

[0083] wherein P m represents the driving motor working condition demand, in kw. V max1 represents the highest forward vehicle speed, in km / h. η t represents the transmission system efficiency. m represents the vehicle mass, in kg. g represents the gravity acceleration, g = 9.8 m / s 2 . f represents the vehicle rolling resistance coefficient. C D represents the wind resistance coefficient. A represents the windward area, in m 2 . m, g, f, C D , and A are vehicle parameters, P m and η t are electric driving parameters.

[0084] In the embodiment, the vehicle speed during vehicle forward driving is generally not limited in advance, and the highest vehicle speed during vehicle backward driving is generally determined according to a preset backward driving speed limiting strategy.

[0085] Further, in an embodiment, the wheel end maximum speed of the differential during vehicle forward driving is calculated by using the following formula (2):

[0086]

[0087] wherein n dri represents the wheel end maximum speed of the differential during vehicle forward driving, in r / min. V max1 represents the highest forward vehicle speed, in km / h. r represents the wheel diameter, in m.

[0088] The wheel end maximum speed of the differential during vehicle backward driving is calculated by using the following formula (3):

[0089]

[0090] wherein n rev represents the wheel end maximum speed of the differential during vehicle backward driving, in r / min. V max2 represents the highest backward vehicle speed, in km / h. r represents the wheel diameter, in m.

[0091] In the embodiment, after the highest forward vehicle speed and the highest backward vehicle speed are converted, the wheel end maximum speed of the differential is converted by using the above formula (2) and formula (3).

[0092] In a specific embodiment, taking the flat ground driving condition of a newly developed electric drive vehicle as an example, the maximum wheel end speed of the differential when the vehicle is moving forward is 1100 rpm, and the maximum wheel end speed of the differential when the vehicle is moving backward is 400 rpm, which is represented by a positive value when the vehicle is moving forward and a negative value when the vehicle is moving backward. The test sample set of the flat ground driving condition is shown in Table 1 below, which contains 13 test sample points, and the conditions that need to be processed are marked with a circle (O):

[0093] Table 1 Test sample set of flat ground driving condition

[0094]

[0095]

[0096] In this embodiment, when performing the lubrication test, the reduction gearbox is installed on the test bench, the differential in the reduction gearbox is controlled to rotate according to the differential wheel end speed in the test sample, and the test bench is controlled to move according to the working condition characteristic parameters in the test sample, i.e., the vehicle is moving forward and the vehicle is moving backward, so that the reduction gearbox simulates the vehicle moving forward and the vehicle moving backward.

[0097] Further, in an embodiment, the above method comprises:

[0098] For the slope driving condition, the maximum climbing degree when the vehicle is climbing and the maximum descending degree when the vehicle is descending are calculated according to the vehicle parameters and the electric drive parameters.

[0099] The maximum wheel end speed of the differential when the vehicle is climbing and the maximum wheel end speed of the differential when the vehicle is descending are calculated according to the preset coefficient and the maximum wheel end speed of the differential when the vehicle is moving forward.

[0100] Different oiling amount parameters, different working condition characteristic parameters, and different differential wheel end speeds are combined to obtain a plurality of different test samples under the slope driving condition. The working condition characteristic parameters of the slope driving condition are used to describe the climbing degree of the vehicle climbing and the descending degree of the vehicle descending.

[0101] In this embodiment, the lubrication performance of the reduction gearbox under the slope driving condition mainly depends on the maximum climbing degree and the maximum descending degree.

[0102] The differential wheel end speed corresponding to the highest vehicle speed when moving forward, and the differential wheel end speed corresponding to the highest vehicle speed when reversing.

[0103] According to automobile theory, the slope angle and the climbing degree are calculated using the following formulas (4) and (5):

[0104]

[0105] i = tan a (5)

[0106] wherein a represents the maximum climbing angle. i represents the maximum climbing degree. t represents the maximum driving force of the motor, in units of N. f represents the rolling resistance of the whole vehicle, in units of N. w represents the air resistance, in units of N. G represents the total weight of the whole vehicle, in units of N.

[0107] For the maximum climbing angle a, the corresponding climbing angle i1 = tan a, and the corresponding maximum speed of the differential wheel end is 0.2 x n dri , n dri is the maximum speed of the differential wheel end when the vehicle is running on flat ground.

[0108] For the medium climbing angle a / 2, the corresponding climbing angle i2 = tan(a / 2), and the corresponding maximum speed of the differential wheel end is 0.4 x n dri .

[0109] For the maximum downhill angle -a, the corresponding climbing angle i3 = tan(-a), and the corresponding maximum speed of the differential wheel end is 0.2 x n dri .

[0110] For the medium downhill angle -a / 2, the corresponding climbing angle i2 = tan(-a / 2), and the corresponding maximum speed of the differential wheel end is 0.4 x n dri .

[0111] In a specific embodiment, taking the slope driving condition of a newly developed electric drive vehicle as an example, the limit climbing degree of the vehicle is calculated to be i1 = 40% through the vehicle parameters and electric drive parameters, the maximum wheel end speed of the differential when the vehicle is climbing is 200rmp, the medium climbing degree of the vehicle is i2 = 25%, the maximum wheel end speed of the differential when the vehicle is climbing is 400rmp, the positive value represents the differential wheel end speed when the vehicle is climbing, and the negative value represents the differential wheel end speed when the vehicle is descending, then the test sample set of the slope driving condition is shown in Table 2 below, which contains 12 test sample working points, wherein the working conditions that need to be processed are marked with a circle (o):

[0112] Table 2 Test sample set of slope driving condition

[0113] Slope 100 200 300 400 Moderate Slope 25％ ○ ○ ○ ○ Extreme Slope 40％ ○ ○ Moderate Downhill -25％ ○ ○ ○ ○ Extreme Downhill -40％ ○ ○

[0114] Further, in an embodiment, the above method comprises:

[0115] For acceleration and deceleration driving conditions, the maximum acceleration liquid surface inclination in the reduction gearbox when the vehicle accelerates and the maximum deceleration liquid surface inclination in the reduction gearbox when the vehicle decelerates are obtained by calculation according to the vehicle parameters and the electric drive parameters.

[0116] The maximum wheel end speed of the differential when the vehicle accelerates is obtained by calculation according to the wheel speed at the inflection point of the external characteristic curve and the reduction gearbox speed ratio.

[0117] The maximum wheel end speed of the differential when the vehicle decelerates is taken as the maximum wheel end speed of the differential when the vehicle accelerates.

[0118] Different fueling parameters, different condition characteristic parameters, and different differential wheel end speeds are combined to obtain a plurality of different test samples under acceleration and deceleration driving conditions. The condition characteristic parameters of the acceleration and deceleration driving conditions are used to describe the acceleration liquid surface inclination in the reduction gearbox when the vehicle accelerates and the deceleration liquid surface inclination in the reduction gearbox when the vehicle decelerates.

[0119] In this embodiment, the liquid level in the reduction gearbox will generate a corresponding liquid level angle due to inertia when the vehicle is in the limit acceleration and limit braking conditions, and the angle has a corresponding conversion relationship with the acceleration and deceleration of the vehicle. The conversion formula (6) of the maximum acceleration liquid surface inclination angle and the conversion formula (7) of the maximum deceleration liquid surface inclination angle are as follows:

[0120] Q = arctan (a / g) (6)

[0121] P = arctan (b / g) (7)

[0122] Q represents the maximum acceleration liquid surface inclination angle, a represents the limit acceleration of the vehicle, and the unit is m / s 2 , and the corresponding maximum acceleration liquid surface inclination is (a / g) × %.

[0123] P represents the maximum deceleration liquid surface inclination angle, b represents the limit deceleration of the vehicle, and the unit is m / s 2 , and the corresponding maximum deceleration liquid surface inclination is (b / g) × %.

[0124] Since the limit acceleration obviously decreases after passing the external characteristic inflection point (before this point, the acceleration of the vehicle is the maximum, and then decreases), the highest vehicle speed corresponding to the limit acceleration condition is the highest speed corresponding to the inflection point of the motor external characteristic curve, and the maximum wheel end speed of the differential corresponding to the limit acceleration condition is the wheel end speed corresponding to the highest speed. The maximum wheel end speed of the differential when the vehicle accelerates is obtained by dividing the wheel speed at the inflection point of the external characteristic curve by the reduction gearbox speed ratio.

[0125] In a specific embodiment, taking the hill driving condition of a newly developed electric drive vehicle as an example, the maximum liquid surface inclination corresponding to the limit acceleration is calculated to be 45% through vehicle parameters and electric drive parameters, the maximum wheel end speed corresponding to the limit acceleration is 400 rpm, the maximum liquid surface inclination corresponding to the limit braking is -60%, the maximum wheel end speed corresponding to the limit acceleration is 1100 rpm, a positive value represents the differential wheel end speed during vehicle acceleration, and a negative value represents the differential wheel end speed during vehicle braking. The test sample set of the acceleration and deceleration driving condition is shown in Table 3, which contains 13 test samples, and the conditions marked with a circle (O) need to be processed:

[0126] Table 3 Test sample set of acceleration and deceleration driving condition

[0127]

[0128] Further, in an embodiment, the method comprises:

[0129] For the side leaning driving condition, the maximum left leaning inclination in the reduction gearbox when the vehicle leans to the left and the maximum right leaning inclination in the reduction gearbox when the vehicle leans to the right are calculated according to the vehicle parameters and the electric drive parameters.

[0130] The maximum wheel end speed of the differential when the vehicle leans to the left and the maximum wheel end speed of the differential when the vehicle leans to the right are calculated according to the preset coefficient and the maximum wheel end speed of the differential when the vehicle advances.

[0131] Different fueling parameters, different condition characteristic parameters, and different differential wheel end speeds are combined to obtain a plurality of different test samples under the side leaning driving condition. The condition characteristic parameters of the side leaning driving condition are used to describe the left leaning inclination when the vehicle leans to the left and the right leaning inclination when the vehicle leans to the right.

[0132] In this embodiment, the maximum inclination angle value is the maximum side leaning angle when the vehicle drives or turns, and the left and right wheels of the vehicle produce different degrees of deflection. Calculating the maximum side leaning angle plays a crucial role in formulating the lubrication condition, and the lubrication test of the maximum inclination angle can effectively evaluate the lubrication risk of the vehicle under the side leaning driving condition. The maximum inclination angle calculation formula (8) is as follows:

[0133]

[0134] Where β represents the maximum side leaning angle, m represents the mass of the vehicle, H represents the height of the vehicle mass center, F represents the vertical load of the tire, and c represents the wheelbase. z

[0135] ​The highest speed corresponding to the medium left-tilt liquid level angle and the bench tilt angle β / 2 is 80% of the highest speed on the flat ground. The highest speed corresponding to the limit left-tilt liquid level angle and the bench tilt angle β is 20% of the highest speed on the flat ground.

[0136] In an embodiment, taking the slope driving condition of a newly developed electric drive vehicle as an example, the limit tilt angle is 20°, the limit tilt is 36%, and the limit tilt highest wheel end speed is 200 rpm, which are obtained by calculating the vehicle parameters and the electric drive parameters. The test sample set of the side-tilt driving condition is shown in Table 4, which contains 24 test sample points, and the conditions that need to be processed are marked with a circle (O):

[0137] Table 4 Test sample set of side-tilt driving condition

[0138] 100 200 300 400 … 900 Moderate Left Tilt Fluid Level, 18% Ramp Inclination ○ ○ ○ ○ ○ ○ Extreme Left Tilt Fluid Level, 36% Ramp Inclination ○ ○ Moderate Right Tilt Fluid Level, 18% Ramp Inclination ○ ○ ○ ○ ○ ○ Extreme Right Tilt Fluid Level, 36% Ramp Inclination ○ ○

[0139] Further, in an embodiment, the method comprises:

[0140] For the slope and side-tilt combined driving condition, the test samples of the slope driving condition and the test samples of the side-tilt driving condition are combined to obtain the test samples of the slope and side-tilt combined driving condition. The condition characteristic parameters of the slope and side-tilt combined driving condition are used to describe the climbing degree of the vehicle climbing, the downhill degree of the vehicle downhill, the left-tilt tilt of the vehicle left-tilt, and the right-tilt tilt of the vehicle right-tilt.

[0141] In this embodiment, the uphill, downhill, left-tilt, and right-tilt are combined respectively to obtain four groups of test attitudes, and the intersection of the slope and tilt attitudes is taken as the specific speed.

[0142] The highest wheel end speed corresponding to the combined condition is 0.4 x n dri .

[0143] In an embodiment, taking the flat driving condition of a newly developed electric drive vehicle as an example, the medium tilt angle is 10°, the medium tilt is 18%, the medium climbing degree is 25%, and the medium climbing degree highest wheel end speed is 40 rpm, which are obtained by calculating the vehicle parameters and the electric drive parameters. The test sample set of the slope and side-tilt combined driving condition is shown in Table 5, which contains 16 test sample points, and the conditions that need to be processed are marked with a circle (O):

[0144] Table 5 Test sample set of slope and side-tilt combined driving condition

[0145]

[0146]

[0147] Furthermore, in one embodiment, the method includes:

[0148] After the reduction gearbox is installed on the test bench, the differential in the reduction gearbox is driven to rotate through the tooling shaft of the test bench. The rotation speed of the tooling shaft is consistent with the rotation speed of the differential wheel end in the test sample. The position and movement of the test bench are consistent with the refueling parameters and operating condition characteristic parameters in the test sample.

[0149] In this embodiment, the various lubrication test conditions generated according to the above steps are summarized into a matrix of all lubrication conditions, and repeated tests are performed according to three refueling amounts: the lower limit, the median, and the upper limit.

[0150] Specifically, the reducer is installed in the specified direction. When the vehicle moves forward, the rotation direction of the reducer input shaft is forward. The reducer is installed in the specified direction. When the vehicle moves backward, the rotation direction of the reducer input shaft is reverse. The temperature is measured by the temperature sensor at the reducer oil drain hole bolt.

[0151] The lubrication matrix of all operating conditions is input to the test bench for lubrication testing. The gearbox lubrication transparent prototype is mounted on the lubrication bench using fixtures. The bench motor drives the gearbox via the differential-end fixture shaft (which belongs to the bench and drives the gearbox through the differential). The gearbox input shaft (normally, the input shaft drives the gearbox through the differential) is unloaded. An oil temperature sensor is placed at the bottom of the gearbox to monitor the temperature of the lubricating fluid.

[0152] During the entire test, only the differential wheel-end speed was loaded. Each speed condition lasted three minutes, with a uniform speed ramp rate of 10 rpm / s. Lubrication video was recorded for each condition using cameras. The primary observation targets were the six bearings of the reduction gearbox, each monitored by a separate camera. The lubricant temperature was maintained between 60°C and 80°C during operation.

[0153] Documentation before the test: 1) Lubricant type. 2) Lubricant filling amount and residual oil amount.

[0154] Test run process documentation: 1) Test bench input speed and torque (fluid resistance on the tooling axis). 2) Test bench tilt angle. 3) Oil pan temperature.

[0155] Post-test documentation: 1) Subjective evaluation score sheet for lubrication results at each lubrication point. 2) Video file of lubricating oil flow under each operating condition.

[0156] The bearing parts of the reduction gearbox lubrication test are focused on, and each bearing position has a corresponding camera to record the lubrication condition. After video recording, the lubrication condition of each bearing position is identified by image recognition. The lubricating liquid is displayed in red, and the picture of the lubrication condition is imported into the shooting picture. The area S of the lubricating liquid is identified by Python algorithm red .

[0157] The specific steps for calculating the area of the lubricating liquid in the picture using Python code include the following: loading the picture, color space conversion, color threshold segmentation, and area statistics. An important step is to use the color threshold segmentation technique, which involves separating pixels of a specific color or color range in the image. Common processing libraries such as OpenCV provide powerful functions for color detection and area calculation.

[0158] First, the picture needs to be loaded and preprocessed. Preprocessing usually includes grayscale conversion, noise removal, etc. The specific steps include picture preprocessing, color threshold segmentation, and calculation of the area of the lubricating liquid region. Picture preprocessing converts the BGR picture to HSV color space. Color threshold segmentation divides the image according to color thresholds, which involves setting the minimum and maximum thresholds of colors in the HSV color space and extracting the corresponding color region through these thresholds. This step is completed through the inRange() function of OpenCV.

[0159] # Define the minimum and maximum thresholds of colors (take red as an example)

[0160] lower_red = np.array([0, 120, 70])

[0161] upper_red = np.array([10, 255, 255])

[0162] According to the threshold, get the mask of the corresponding color region

[0163] mask = cv2.inRange(hsv_image, lower_blue, upper_blue)

[0164] Perform AND operation on the mask and the original picture to extract the colored part

[0165] color_segment = cv2.bitwise_and(image, image, mask = mask)

[0166] Calculate the area of the lubricating liquid (red) region

[0167] After obtaining the color mask, the steps to calculate the area of the color are as follows:

[0168] The number of pixel points of the mask red color is calculated, that is, the area of the color region (pixel unit)

[0169] lower_red = np.array([0, 120, 70])

[0170] upper_red = np.array([10, 255, 255])

[0171] red_area = calculate_area_of_color(hsv_image, lower_red, upper_red)

[0172] The value of red_area is the area S of the identified lubricating liquid red .

[0173] The amount of lubricating liquid is quantitatively scored, and the bearing at the bearing position is taken as an example, and the area S is taken as the reference base , Proportion = S red / S base × 100%, and the lubrication result is objectively scored according to the gradient of the area ratio, and the specific scoring table is shown in Table 6:

[0174] Table 6 Lubrication test result scoring table

[0175] Lubricant Proportion to Base Area Objective Score Subjective Evaluation ＞60％ 4 Full Lubrication > 40% and < 60% 3 Good Lubrication > 20% and < 40% 2 Sufficient Lubrication > 0% and < 20% 1 Light Lubrication ＝0％ 0 No Lubrication

[0176] The customer scores the bearings at different positions corresponding to the sample machine state under the lubrication condition of a single rotating speed, and the differential wheel end rotating speed is 1000 rpm and the oiling amount is the median value under the flat driving condition. The specific lubrication test scoring record table is shown in Table 7:

[0177] Table 7 Lubrication test result scoring table under flat driving condition

[0178] Operating Speed (Flat Drive Wheel End 1000 rpm Median Oil Quantity) Objective Score Input Shaft Bearing A 3 Input Shaft Bearing B 2 Intermediate Shaft Bearing C 2 Intermediate Shaft Bearing D 2 Differential Bearing E 1 Differential Bearing F 1

[0179] The series working condition score record is recorded, for example, the lubrication test results of the vehicle forward and the vehicle backward under the flat driving condition are scored, and the summary table is shown in Table 8:

[0180] Table 8 Lubrication test result scoring summary table of vehicle forward and vehicle backward under flat driving condition

[0181]

[0182]

[0183] All working conditions are scored and recorded, and all working conditions are weighted and risk assessed.

[0184] After the three types of oiling amounts are completed for all working conditions, a weighted score is given to all working conditions corresponding to each bearing, and risk warnings are given for working conditions and bearing numbers with a score less than or equal to 1.

[0185] Based on the above lubrication result matrix, the oil quantity is evaluated and the oil passages of bearing accessories with lubrication risks are optimized accordingly.

[0186] This invention generates corresponding lubrication conditions based on vehicle and electric drive parameters, and simultaneously analyzes and evaluates the lubrication results using a user-quantified evaluation method. This patent proposes a system for generating and quantitatively evaluating the lubrication conditions of electric drive reduction gearboxes. This allows for optimal lubrication conditions to be used for electric drive reduction gearbox assessments, thereby reducing sample size and testing costs. This objective evaluation method avoids the errors and non-repeatability inherent in subjective evaluations.

[0187] In a second aspect, an embodiment of the present application also provides an electric drive reduction gearbox lubrication test system.

[0188] In one embodiment, referring to Figure 3 , Figure 3 This is a functional module diagram of an embodiment of the electric drive reduction gearbox lubrication test system of this application. Figure 3 As shown in the figure, the electric drive reduction gearbox lubrication test system includes:

[0189] Preprocessing module 1 is configured to calculate, based on preset vehicle parameters and electric drive parameters, operating condition characteristic parameters for each lubrication test condition and / or the maximum wheel-end speed of the differential in the reduction gearbox. The multiple lubrication test conditions include a flat-land driving condition, a ramp driving condition, an acceleration / deceleration driving condition, a rolling driving condition, and a combined ramp and rolling driving condition. These operating condition characteristic parameters are used to describe the characteristics of the lubrication test conditions.

[0190] The sample generation module 2 is used to generate a plurality of different test samples for each lubrication test condition. Each test sample includes a refueling amount parameter, a working condition characteristic parameter, and a differential wheel end speed.

[0191] Test Module 3 performs lubrication tests on the gearbox on the test bench for each test sample. During the test, it collects real-time images of each bearing in the gearbox. Image recognition is performed on the real-time images to determine the ratio of the lubricating oil area to the total bearing area. This ratio is used to quantitatively evaluate the lubrication results.

[0192] In this embodiment, considering the vehicle parameters and electric drive parameters, the lubrication test samples in various lubrication test conditions are generated by calculation, and the oiling amount parameter, the working condition characteristic parameter, and the differential wheel end speed are included in different lubrication test samples, so that the real driving scene can be simulated scientifically and comprehensively, and the comprehensiveness and accuracy of the lubrication test of the reduction gearbox are improved.

[0193] During the test, real-time images at each bearing in the reduction gearbox are collected, image recognition is performed on the real-time images to obtain the ratio of the lubricating oil area to the total bearing area, and the test result is obtained according to the ratio, so that the objectivity and accuracy of the test evaluation result are improved in a quantitative evaluation manner.

[0194] The functions of each module in the electric drive reduction gearbox lubrication test system correspond to the steps in the electric drive reduction gearbox lubrication test method embodiment, and the functions and implementation processes will not be described here.

[0195] It should be noted that the sequence numbers of the embodiments of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0196] The terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or device. The terms "first", "second" and "third" and the like are used to distinguish different objects, and do not represent the order or limit the types of "first", "second" and "third".

[0197] In the description of the embodiments of the present application, "exemplary", "for example" or "for instance" is used to represent an example, illustration or description. Any embodiment or design scheme described as "exemplary", "for example" or "for instance" in the embodiments of the present application should not be interpreted as more preferred or more advantageous than other embodiments or design schemes. On the contrary, the words "exemplary", "for example" or "for instance" are intended to present the relevant concept in a specific manner.

[0198] In the description of the embodiments of the present application, unless otherwise specified, " / " represents or, for example, A / B can represent A or B. "And / or" in the text only represents the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent three cases of A alone, A and B together, and B alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0199] In some of the processes described in the embodiments herein, there is no particular requirement as to the order of the operations or steps. It should be understood that these operations or steps can be executed in an order other than the order in which they appear in the embodiments herein or in parallel, and the serial numbers of the operations are only used to distinguish different operations, and the serial numbers themselves do not represent any execution order. In addition, these processes can include more or fewer operations, and these operations or steps can be executed in sequence or in parallel, and these operations or steps can be combined.

[0200] From the above description of the embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be realized by means of software and the necessary general hardware platform, of course, they can also be realized by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as a ROM / RAM, a magnetic disk, or an optical disc) as described above, and includes a number of instructions for causing a terminal device to execute the methods described in the embodiments of the present application.

[0201] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A method of testing the lubrication of an electrically driven reduction gearbox, characterized in that, The method comprises: According to the preset vehicle parameters and electric drive parameters, the working condition characteristic parameters and / or the wheel end maximum speed of the differential in the reduction gearbox under multiple lubrication test working conditions are obtained through calculation; the multiple lubrication test working conditions include flat ground driving working condition, slope driving working condition, acceleration and deceleration driving working condition, side leaning driving working condition, and slope and side leaning combined driving working condition; the working condition characteristic parameters are used to describe the characteristics of the lubrication test working condition; For each lubrication test working condition, multiple different test samples are generated; each test sample comprises an oiling amount parameter, a working condition characteristic parameter, and a differential wheel end speed; According to each test sample, the reduction gearbox on the test bench is subjected to lubrication test, and real-time images of each bearing in the reduction gearbox are collected during the test; image recognition is performed on the real-time images to obtain the ratio of the lubricating oil area to the total bearing area, and the lubrication result is quantitatively evaluated according to the ratio; the larger the ratio, the better the lubrication effect.

2. The electric drive reduction gearbox lubrication test method of claim 1, wherein, The method comprises: For the flat ground driving working condition, the highest forward speed of the vehicle when driving forward and the highest backward speed of the vehicle when driving backward are obtained through calculation according to the vehicle parameters and the electric drive parameters; The wheel end maximum speed of the differential when the vehicle drives forward is obtained through calculation according to the highest forward speed; the wheel end maximum speed of the differential when the vehicle drives backward is obtained through calculation according to the highest backward speed; Different oiling amount parameters, different working condition characteristic parameters, and different differential wheel end speeds are combined to obtain multiple different test samples under the flat ground driving working condition; the working condition characteristic parameters of the flat ground driving working condition are used to describe the vehicle driving forward and the vehicle driving backward.

3. The electric drive reduction gearbox lubrication test method of claim 2, wherein, The highest forward speed is obtained through calculation according to the following formula: wherein, represents the driving motor operating condition demand, in units of kw; represents the maximum forward vehicle speed, in units of km / h; represents the transmission system efficiency; m represents the mass of the vehicle, in units of kg; g represents the gravitational acceleration, g = 9.8 ; f represents the rolling resistance coefficient of the vehicle; represents the wind resistance coefficient; A represents the windward area, in units of ; m, g, f, , and A are vehicle parameters, and are electric drive parameters.

4. The electric drive reduction gearbox lubrication test method of claim 2, wherein, The wheel end maximum speed of the differential when the vehicle drives forward is obtained through calculation according to the following formula: wherein represents the maximum wheel end speed of the differential when the vehicle is moving forward, in r / min; represents the maximum wheel end speed of the differential when the vehicle is moving backward, in r / min; and represents the maximum wheel end speed of the differential when the vehicle is moving forward, in r / min; wherein, represents the wheel end maximum speed of the differential when the vehicle is backing up, in r / min; represents the highest backing speed, in km / h; r represents the wheel diameter, in m.

5. The electric drive reduction gearbox lubrication test method of claim 1, wherein, The method comprises: For the slope driving working condition, the maximum climbing degree when the vehicle drives uphill and the maximum downhill degree when the vehicle drives downhill are obtained through calculation according to the vehicle parameters and the electric drive parameters; The wheel end maximum speed of the differential when the vehicle drives uphill and the wheel end maximum speed of the differential when the vehicle drives downhill are obtained through calculation according to the preset coefficient and the wheel end maximum speed of the differential when the vehicle drives forward; Different oiling amount parameters, different working condition characteristic parameters, and different differential wheel end speeds are combined to obtain multiple different test samples under the slope driving working condition; the working condition characteristic parameters of the slope driving working condition are used to describe the climbing degree of the vehicle driving uphill and the downhill degree of the vehicle driving downhill.

6. The electric drive reduction gearbox lubrication test method of claim 1, wherein, The method comprises: For the acceleration and deceleration driving working condition, the maximum acceleration liquid surface inclination in the reduction gearbox when the vehicle accelerates and the maximum deceleration liquid surface inclination in the reduction gearbox when the vehicle decelerates are obtained through calculation according to the vehicle parameters and the electric drive parameters; The wheel end maximum speed of the differential when the vehicle accelerates is obtained through calculation according to the wheel speed at the inflection point of the external characteristic curve and the speed ratio of the reduction gearbox; The wheel end maximum speed of the differential when the vehicle drives forward is used as the wheel end maximum speed of the differential when the vehicle decelerates; Different oiling amount parameters, different working condition characteristic parameters, and different differential wheel end speeds are combined to obtain a plurality of different test samples in the acceleration and deceleration driving working condition; the working condition characteristic parameters of the acceleration and deceleration driving working condition are used to describe the acceleration liquid surface inclination in the reduction gearbox when the vehicle accelerates and the deceleration liquid surface inclination in the reduction gearbox when the vehicle decelerates.

7. The electric drive reduction gearbox lubrication test method of claim 1, wherein, The method comprises: For the side leaning driving working condition, the left leaning maximum inclination in the reduction gearbox when the vehicle leans left and the right leaning maximum inclination in the reduction gearbox when the vehicle leans right are obtained through calculation according to the whole vehicle parameters and the electric drive parameters; The left leaning maximum speed of the differential when the vehicle leans left and the right leaning maximum speed of the differential when the vehicle leans right are obtained through calculation according to the preset coefficient and the maximum speed of the differential wheel end when the vehicle advances; Different oiling amount parameters, different working condition characteristic parameters, and different differential wheel end speeds are combined to obtain a plurality of different test samples in the side leaning driving working condition; the working condition characteristic parameters of the side leaning driving working condition are used to describe the left leaning inclination when the vehicle leans left and the right leaning inclination when the vehicle leans right.

8. The electric drive reduction gearbox lubrication test method of claim 1, wherein, The method comprises: For the slope and side leaning combined driving working condition, the test samples of the slope driving working condition and the test samples of the side leaning driving working condition are combined to obtain the test samples of the slope and side leaning combined driving working condition; the working condition characteristic parameters of the slope and side leaning combined driving working condition are used to describe the climbing degree when the vehicle climbs, the downhill degree when the vehicle descends, the left leaning inclination when the vehicle leans left, and the right leaning inclination when the vehicle leans right.

9. The electric drive reduction gearbox lubrication test method of claim 1, wherein, The method comprises: After the reduction gearbox is installed on the test bench, the differential in the reduction gearbox is driven to rotate by the tool shaft of the test bench; the rotation speed of the tool shaft is consistent with the differential wheel end speed in the test sample; the position and action of the test bench are consistent with the oiling amount parameter and the working condition characteristic parameter in the test sample.

10. An electrically driven reduction gearbox lubrication test system characterized by, The system comprises: A preprocessing module is configured to obtain the working condition characteristic parameters in a plurality of lubrication test working conditions and / or the maximum speed of the differential wheel end in the reduction gearbox through calculation according to the preset whole vehicle parameters and electric drive parameters; the plurality of lubrication test working conditions comprise the flat ground driving working condition, the slope driving working condition, the acceleration and deceleration driving working condition, the side leaning driving working condition, and the slope and side leaning combined driving working condition; the working condition characteristic parameters are used to describe the characteristics of the lubrication test working condition; A sample generation module is configured to generate a plurality of different test samples for each lubrication test working condition; each test sample comprises an oiling amount parameter, a working condition characteristic parameter, and a differential wheel end speed; A test module is configured to perform lubrication test on the reduction gearbox on the test bench according to each test sample respectively, and collect real-time images at each bearing in the reduction gearbox during the test; the real-time images are subjected to image recognition to obtain the ratio of the lubricating oil area to the total bearing area; the lubrication result is quantitatively evaluated according to the ratio; the larger the ratio is, the better the lubrication effect is.

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