A high-load and vibration test device and test method for automobile wheel hub bearings

Abstract

The application discloses a kind of automobile wheel hub bearing high load and vibration test device and test method, it is related to wheel hub bearing test field, including L type loading arm, connecting disc, brake disc, wheel hub bearing test sample and wheel hub bearing testing machine, the flange of one end of wheel hub bearing test sample is sequentially connected with brake disc, connecting disc and fastened, connecting disc is connected by the main shaft of wheel hub bearing testing machine and driven, the flange of the other end of wheel hub bearing test sample is fixed on connecting plate, connecting plate is surface connection fixed with the vertical section of L type loading arm, vibration sensor is installed on the upper end surface of connecting plate, temperature sensor is installed on the non-rotating end surface of wheel hub bearing test sample;Joint loading point is set on the horizontal section of L type loading arm, and the radial, axial loading device of wheel hub bearing testing machine is jointly loaded to the joint loading point.The application can comprehensively evaluate the vibration condition of wheel hub bearing test sample, understand its overall vibration level, judge the mode and state of wheel hub bearing test sample failure.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hub bearing test, in particular to a kind of automobile hub bearing high load and vibration test device and test method. BACKGROUND

[0002] Hub bearing is one of the key components of automobile, its main role is to bear weight and provide accurate guide for the rotation of hub, need to bear radial load and axial load simultaneously.When hub bearing fails, it will cause noise, bearing heating and other phenomena, at the same time, abnormal vibration is generated.Currently, hub bearing unit tester is usually used to measure load, temperature and vibration of hub bearing unit.

[0003] For example, Chinese patent document (CN111458055A) discloses a heavy truck hub bearing temperature monitoring sensor tester and test method, which includes a support, a power loading system for driving the hub bearing to rotate, a heating system, a signal measurement system and a control system, and further includes a fixing assembly for fixing the hub bearing, the fixing assembly includes a brake disc surrounded by the heating system and a bearing compression rod; the signal measurement system includes a wireless temperature sensor installed on the hub bearing, and a wired temperature sensor and a vibration sensor arranged in the compression rod inner sleeve. However, when the hub bearing unit tester measures vibration, only the measurement value obtained by the vibration sensor is recorded, without comprehensive evaluation and calculation, so the state and mode of bearing failure cannot be accurately determined. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art, and provides a kind of automobile hub bearing high load and vibration test device and test method, can comprehensively evaluate the vibration condition of hub bearing test sample, understand its overall vibration level, judge the mode and state of hub bearing test sample failure.

[0005] The purpose of the present application is achieved by the following technical scheme: the automobile hub bearing high load and vibration test device includes an L-shaped loading arm, a connecting disc, a brake disc, a hub bearing test sample and a hub bearing tester, one end flange of the hub bearing test sample is sequentially connected and fastened with the brake disc and the connecting disc, the connecting disc is connected and driven by the main shaft of the hub bearing tester, the other end flange of the hub bearing test sample is fixed on a connecting plate, the connecting plate is surface-connected and fixed with the vertical section of the L-shaped loading arm, a vibration sensor is installed on the upper end face of the connecting plate, and a temperature sensor is installed on the non-rotating end face of the hub bearing test sample; a joint loading point is provided on the horizontal section of the L-shaped loading arm, the radial and axial loading devices of the hub bearing tester are jointly loaded on the joint loading point, and radial and axial loads are applied to the joint loading point.

[0006] As a further technical solution, the distance from the joint loading point to the center of the main shaft, i.e. the axial loading arm, is equal to the radius R of the wheel in the real vehicle, the joint loading point is collinear with the wheel center line of the wheel, and the distance from the wheel center line to the brake disc end face is equal to the radial loading offset ET.

[0007] As a further technical solution, the installation direction of the vibration sensor is consistent with the radial loading direction.

[0008] The test method using the above-mentioned automobile wheel hub bearing high load and vibration test device comprises the following steps:

[0009] First step: test device setup: install the wheel hub bearing test sample and the L-shaped loading arm on the wheel hub bearing test machine, ensure that the axial loading arm is equal to the wheel radius R, and at the same time, the radial loading offset ET is equal to the distance from the wheel center line to the brake disc end face, install the vibration sensor to the upper end face of the connecting plate, and the installation direction of the vibration sensor is consistent with the radial loading direction;

[0010] Second step: set test parameters: set the main shaft speed of the wheel hub bearing test machine, i.e. the test speed n, set the radial load Fr and the axial load Fa, start the loading test, and collect the original signal value output by the vibration sensor;

[0011] Third step: vibration value calculation: filter the original signal value obtained in the second step to obtain the required vibration value, and then calculate the root mean square value G-RMS;

[0012] Fourth step: judgment of eligibility: stop the test when the test is performed to the set time or at least one of the vibration sensor and the temperature sensor sends an alarm signal, remove the wheel hub bearing test sample for inspection, and judge the eligibility of the test.

[0013] As a further technical solution, in the second step, the test speed n = v * 1000 / (2π * R * 60), where v is the real vehicle speed, unit: km / h, and R is the wheel radius; the radial load Fr = W / 2 + W*g*H / L, where W is the axle load, g is the lateral acceleration coefficient, H is the gravity center height, and L is the wheel track, which are measured by the real vehicle; the axial load Fs = Fr*g, and Fs has two opposite loading directions, namely Fs1 and Fs2, Fs1 is the load when turning inward, and Fs2 is the load when turning outward.

[0014] In the second step, the wheel hub bearing test sample has the following three loading states, respectively:

[0015] ① No radial and axial loading, only the main shaft of the wheel hub bearing test machine provides the test speed n;

[0016] ② Apply radial load Fr, and at the same time, the main shaft of the wheel hub bearing test machine provides the test speed n;

[0017] ③ Apply the inward turning axial load Fs with a lateral acceleration coefficient of 0.5g, while applying the radial load Fr, and the wheel hub bearing test machine spindle provides the test rotational speed n;

[0018] As a further technical solution, for the above three loading states, the vibration values under the corresponding three test conditions are measured and obtained in the third step.

[0019] As a further technical solution, in the second step, if the ratio of the center of gravity height H to the wheelbase L is invalid, the ratio is taken as 0.43 for a truck and 0.36 for a passenger car.

[0020] As a further technical solution, in the third step, the frequency range included in the filtering process is: above 4 times the ball defect frequency BSF and below 10 times the inner ring defect frequency BPFI, wherein:

[0021] BSF = PD / 2 / BD x RF x {1-[(BD / PD) x Cos(CA)]}, 2

[0022] BPFI = N / 2 x RF x {1+[(BD / PD) x Cos(CA)]};

[0023] The symbols are as follows: N is the number of ball bearings of the wheel hub bearing sample, BD is the ball diameter, PD is the pitch diameter, i.e. the average of the inner and outer raceway diameters of the wheel hub bearing sample, CA is the contact angle of the wheel hub bearing sample, and RF is the rotational frequency converted from the test rotational speed n.

[0024] As a further technical solution, in the fourth step, the wheel hub bearing sample is disassembled for inspection, with the following requirements: the exudation rate of the lubricating grease exuding from the surface of the sealing ring is not more than 5%, the operating temperature of the wheel hub bearing sample, i.e. the temperature measured by the temperature sensor, is not more than 110℃, the wheel hub bearing sample is not allowed to have raceway fatigue failure, and the inner sealing of the wheel hub bearing sample is not allowed to have frictional contact with the steel ball; if at least one of the above requirements is not met, it is considered that the high-load test of the wheel hub bearing sample does not meet the requirements.

[0025] The beneficial effects of the present application are:

[0026] 1. When calculating the vibration of the wheel hub bearing sample, the original signal obtained by the vibration sensor is first filtered, and then the root mean square value of the filtered vibration value is calculated, avoiding the influence of other noise, and reflecting the real failure mode and state of the wheel hub bearing sample;

[0027] ​2. Three loading modes were provided for the wheel hub bearing specimens (no axial or radial load, only spindle rotation; radial load applied and spindle rotation; axial and radial loads applied simultaneously, and spindle rotation), which can comprehensively evaluate the vibration of the wheel hub bearing and understand its overall vibration level;

[0028] 3. It can simultaneously monitor the temperature and vibration level of the wheel hub bearing specimen, and reflect the effective / failure state of the wheel hub bearing specimen in real time. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the present invention.

[0030] Figure 2 This is a curve showing the relationship between the test time s, the test rotation speed n, and the axial load Fs in the second step of this embodiment of the invention.

[0031] Explanation of reference numerals in the attached drawings: 1. L-shaped loading arm; 2. Connecting disc; 3. Brake disc; 4. Connecting plate; 5. Wheel hub bearing sample; 6. Vibration sensor; 7. Temperature sensor; 8. Wheel hub bearing centerline; 9. Wheel centerline; 10. Combined loading point; 11. Vertical section; 12. Horizontal section. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings:

[0033] Example: As attached Figure 1 As shown, this high-load and vibration testing device for automotive wheel hub bearings includes an L-shaped loading arm 1, a connecting disc 2, a brake disc 3, a connecting plate 4, a wheel hub bearing sample 5, a vibration sensor 6, a temperature sensor 7, a wheel hub bearing centerline 8, a wheel centerline 9, a combined loading point 10, a vertical section 11, and a horizontal section 12.

[0034] The test device needs to be used in cooperation with a hub bearing testing machine. The existing hub bearing testing machine generally has a main shaft, a radial loading device and an axial loading device. One end flange (inner ring flange) of the hub bearing test sample 5 is sequentially fastened by bolt connection with the brake disc 3 and the connecting disc 2, the shaft hole of the connecting disc 2 is connected and driven by the main shaft of the hub bearing testing machine, the other end flange (outer ring flange) of the hub bearing test sample 5 is fixed on the connecting plate 4, the connecting plate 4 is fixedly connected with the surface of the vertical section 11 of the L-shaped loading arm 1, the upper end surface of the connecting plate 4 is provided with a vibration sensor 6, preferably, the installation direction of the vibration sensor 6 is consistent with the radial loading direction, a temperature sensor 7 is installed on the non-rotating end surface (outer ring wall) of the hub bearing test sample 5, and the temperature sensor 7 can detect the real-time temperature of the hub bearing test sample 5 during operation. The joint loading point 10 is arranged on the horizontal section 12 of the L-shaped loading arm 1, the radial and axial loading devices of the hub bearing testing machine are jointly loaded on the joint loading point 10, and the radial and axial loads are applied to the joint loading point 10. Further, the distance from the joint loading point 10 to the center of the main shaft, i.e. the axial loading force arm, is equal to the radius R of the wheel in the real vehicle, the joint loading point 10 is collinear with the wheel center line 9 of the wheel, the hub bearing center line 8 is located on the left side of the wheel center line 9, and the distance from the wheel center line 9 to the end surface of the brake disc 3 is equal to the radial loading offset ET.

[0035] The test method using the above-mentioned high-load and vibration test device for automobile hub bearings comprises the following steps:

[0036] First step: test device building: install the hub bearing test sample 5 and the L-shaped loading arm 1 on the hub bearing testing machine, ensure that the axial loading force arm is equal to the wheel radius R, and at the same time, the radial loading offset ET is equal to the distance from the wheel center line 9 to the end surface of the brake disc 3, install the vibration sensor 6 on the upper end surface of the connecting plate 4, and the installation direction of the vibration sensor 6 is consistent with the radial loading direction;

[0037] Second step: setting test parameters: set the main shaft speed of the hub bearing testing machine, i.e. the test speed n, which is n = v * 1000 / (2 * pi * R * 60), wherein v is the vehicle speed, the unit is km / h, and R is the wheel radius. Taking the vehicle speed v = 100 km / h as an example, n = (100 * 1000 / (2 * 3.14 * R * 60), the unit is revolutions per minute. Then set the radial load Fr = W / 2 + W * g * H / L, wherein W is the axle load of the front axle or the rear axle of the automobile, g is the lateral acceleration coefficient, H is the gravity center height, and L is the wheel track, which are measured from the real vehicle. If the ratio of the gravity center height H to the wheel track L is invalid, the ratio is taken as 0.43 for trucks (pickups, large van trucks, SUVs, etc.), and the ratio is taken as 0.36 for passenger cars. Then set the axial load Fs = Fr * g, such as Figure 1The Fs has two opposite loading directions, namely Fs1 and Fs2, as shown in the figure. Fs1 is the load when turning inward, and Fs2 is the load when turning outward. Preferably, the calculated load spectrum of a certain vehicle model is as follows: taking the rotating speed n = 700 rpm, Fr = 10.9 kN, Fs1 = 1.8 kN, and Fs2 = 12.0 kN, the duration of the load Fs1 t1 = 30 s, and the duration of the load Fs2 t2 = 5 s. The relationship curve of the test time s with the test rotating speed n and the axial load Fs is obtained as shown in the figure. Figure 2

[0038] After the parameters of the hub bearing tester are set, the loading test is started, and the original signal value output by the vibration sensor 6 is collected. Preferably, the hub bearing test sample 5 has the following three loading states, respectively:

[0039] ① No radial and axial loading, only the hub bearing tester main shaft provides the test rotating speed n;

[0040] ② Apply the radial load Fr, and the hub bearing tester main shaft provides the test rotating speed n;

[0041] ③ Apply the inward turning axial load Fs with a lateral acceleration coefficient of 0.5g, apply the radial load Fr, and the hub bearing tester main shaft provides the test rotating speed n;

[0042] For the above three loading states, the vibration values under the corresponding three test conditions are measured and obtained in the third step.

[0043] Third step: vibration value calculation: filter the original signal value obtained in the second step to obtain the required vibration value, and then calculate the root mean square value G-RMS. The vibration signal reading time of the vibration G-RMS root mean square value should be more than 6s to 10s to reduce the influence of instantaneous vibration peaks. The frequency range included in the filter processing is: above 4 times the ball defect frequency BSF and below 10 times the inner ring defect frequency BPFI, wherein:

[0044] BSF = PD / 2 / BD x RF x {1-[(BD / PD) x Cos(CA)]}, 2},

[0045] BPFI = N / 2 x RF x {1+[(BD / PD) x Cos(CA)]};

[0046] ​The symbols are explained as follows: N is the number of balls of the hub bearing sample 5, BD is the ball diameter, PD is the pitch diameter, i.e. the average of the inner ring and outer ring raceway diameters of the hub bearing sample 5, CA is the contact angle of the hub bearing sample 5, and RF is the rotation frequency converted from the test speed n. The high-frequency vibration within the two frequency ranges (between 4 times BSF and 10 times BPFI) mainly reflects the peeling of the surface of one or more balls, the low-frequency vibration is mainly the vibration caused by the fixture, and the low-pass filtering should not exceed 5 times the rotation frequency RF.

[0047] Step 4: eligibility judgment: stop the test when the test is conducted to the set time (preferably 2 hours) or at least one of the vibration sensor 6 and the temperature sensor 7 sends an alarm signal, disassemble the hub bearing sample 5 for dismounting inspection, and the requirements are as follows: a small amount of lubricating grease is allowed to seep out of the surface of the sealing ring (the seepage rate is not more than 5%), the operating temperature of the hub bearing sample 5, i.e. the temperature measured by the temperature sensor 7, is not more than 110℃, the hub bearing sample 5 is not allowed to have raceway fatigue failure, and the hub bearing sample 5 is not allowed to have frictional contact with the steel ball at the sealing position; if at least one of the above requirements is not met, the high-load test of the hub bearing sample 5 is considered to be not qualified. During the test, when the vibration value is 3-5 times the initial value compared with the initial vibration, we consider that the bearing has abnormal vibration and may fail, and needs to be stopped for inspection. When the temperature of the bearing during the test reaches 110℃, it also needs to be stopped for inspection.

[0048] The device and test method provided by the application are widely applicable to automobile hub bearing production enterprises and automobile manufacturers, and mainly test the durability of the hub bearing under high load, and evaluate the contact fatigue resistance of the hub bearing raceway. The design of the test device under high load of the hub bearing unit is solved, the installation and measurement methods of the temperature sensor and the vibration sensor are described, the connection methods and loading methods of the sample and the fixture are described, and the like; it provides a program loading, test process control and test result evaluation method for high-load test, and provides a solution for simulating the working condition of the automobile under heavy load.

[0049] It can be understood that equivalent replacement or changes to the technical solutions and inventive concepts of the application by those skilled in the art should fall within the protection scope of the claims attached to the application.

Claims

1. A method for high-load and vibration testing of automotive wheel hub bearings, characterized in that: A high-load and vibration testing device for automotive wheel hub bearings is adopted. The testing device includes an L-shaped loading arm (1), a connecting plate (2), a brake disc (3), a wheel hub bearing specimen (5), and a wheel hub bearing testing machine. One end flange of the wheel hub bearing specimen (5) is connected and fastened to the brake disc (3) and the connecting plate (2) in sequence. The connecting plate (2) is driven by the main shaft of the wheel hub bearing testing machine. The other end flange of the wheel hub bearing specimen (5) is fixed on the connecting plate (4). The connecting plate (4) is connected and fixed to the surface of the vertical section (11) of the L-shaped loading arm (1). A vibration sensor (6) is installed on the upper end surface of the connecting plate (4). A temperature sensor (7) is installed on the non-rotating end face of the bearing sample (5); a joint loading point (10) is set on the horizontal section (12) of the L-shaped loading arm (1), and the radial and axial loading devices of the wheel hub bearing testing machine are jointly loaded onto the joint loading point (10) to apply radial and axial loads to the joint loading point (10); the distance from the joint loading point (10) to the center of the main shaft, i.e., the axial loading arm, is equal to the radius R of the wheel in the actual vehicle, the joint loading point (10) is collinear with the wheel centerline (9) of the wheel, and the distance from the wheel centerline (9) to the end face of the brake disc (3) is equal to the radial loading offset ET; The method Includes the following steps: Step 1: Test setup: Install the wheel bearing sample (5) and L-shaped loading arm (1) onto the wheel bearing testing machine, ensuring that the axial loading arm is equal to the wheel radius R, and the radial loading offset ET is equal to the distance from the wheel centerline (9) to the end face of the brake disc (3). Install the vibration sensor (6) onto the upper end face of the connecting plate (4), and the installation direction of the vibration sensor (6) is consistent with the radial loading direction. Step 2: Set test parameters: Set the spindle speed of the wheel hub bearing testing machine, i.e., the test speed n, set the radial load Fr and the axial load Fa, start the loading test, and collect the original signal value output by the vibration sensor (6); Step 3: Vibration value calculation: Filter the original signal value obtained in step 2 to obtain the required vibration value, and then calculate its root mean square value G-RMS. Step 4: Qualification judgment: When the test is carried out to the set time or when at least one of the vibration sensor (6) and temperature sensor (7) issues an alarm signal, stop the test, remove the wheel hub bearing sample (5) for inspection, and judge the qualification of the test.

2. The test method according to claim 1, characterized in that: In the second step, the test rotational speed n = v * 1000 / (2π * R * 60), where v is the actual vehicle speed in km / h and R is the wheel radius; the radial load Fr = W / 2 + W * g * H / L, where W is the axle load, g is the lateral acceleration coefficient, H is the center of gravity height, and L is the wheelbase, both of which are measured from the actual vehicle; the axial load Fs = Fr * g, and Fs has two opposite loading directions, namely Fs1 and Fs2, where Fs1 is the load when turning inward and Fs2 is the load when turning outward.

3. The test method according to claim 2, characterized in that: In the second step, the hub bearing sample (5) has the following three loading states: Without radial or axial loading, the test speed n is provided only by the spindle of the wheel hub bearing testing machine; A radial load Fr is applied, while the spindle of the wheel hub bearing testing machine provides the test speed n; An inwardly rotating axial load Fs with a lateral acceleration coefficient of 0.5g is applied, along with a radial load Fr, and the spindle of the wheel hub bearing testing machine provides the test speed n; For the three loading states mentioned above, the vibration values ​​corresponding to the three test conditions are measured and obtained in the third step.

4. The test method according to claim 3, characterized in that: In the second step, if the ratio of center of gravity height H to wheel track L is invalid, then the ratio is 0.43 for trucks and 0.36 for passenger cars.

5. The test method according to claim 4, characterized in that: In the third step, the frequency range included in the filtering process is: above 4 times the ball defect frequency (BSF) and below 10 times the inner ring defect frequency (BPFI), where: BSF=PD / 2 / BD×RF×{1-[(BD / PD)×Cos(CA)] 2 }, BPFI=N / 2×RF×{1+[(BD / PD)×Cos(CA)]}; The symbols are explained as follows: N is the number of balls in the wheel hub bearing sample (5), BD is the ball diameter, PD is the pitch circle diameter, which is the average value of the inner and outer raceway diameters of the wheel hub bearing sample (5), CA is the contact angle of the wheel hub bearing sample (5), and RF is the rotational frequency obtained by converting the test rotational speed n.

6. The test method according to claim 5, characterized in that: In the fourth step, the wheel hub bearing sample (5) is disassembled for inspection, and the following requirements are made: the leakage rate of grease from the surface of the sealing ring shall not exceed 5%; the operating temperature of the wheel hub bearing sample (5), i.e., the temperature measured by the temperature sensor (7), shall not exceed 110°C; the wheel hub bearing sample (5) shall not experience raceway fatigue failure; and the inner seal of the wheel hub bearing sample (5) shall not rub against the steel ball. If at least one of the above requirements is not met, the high-load test of the wheel hub bearing sample (5) is considered to be unqualified.

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