A method for evaluating heat exchange characteristics of a ball bearing outer ring and a flow channel

Abstract

The present application relates to the technical field of bearing cooling and measurement, and particularly relates to a ball bearing outer ring heat exchange experiment method. By establishing a ball bearing outer ring heat exchange experiment device, the heat exchange of the flow channel of the bearing outer ring is tested, and through flow channel heat exchange characteristic evaluation and experiment data processing, the flow channel heat exchange characteristic is obtained, the trend graph of the outer surface temperature of the measured bearing outer ring changing with the flow direction under different heating amounts is obtained, and the influence of the heating amount on the heat exchange characteristic is analyzed. The present application realizes the separately adjustable heating of the power of the bearing outer ring, can quantitatively obtain the steady-state temperature distribution of the measuring points on the outer wall of the experimental bearing outer ring under different heating and oil supply conditions, and the pressure loss inside the flow channel, evaluates the cooling effect and the heat exchange characteristic of the bearing outer ring under multiple working conditions, and provides technical support for the inner flow cooling technology of the outer ring.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bearing cooling and measurement, and particularly relates to a ball bearing outer ring heat exchange experiment method. BACKGROUND

[0002] Bearing is one of important parts in mechanical transmission system, plays a role of supporting and positioning for rotating parts, reduces friction coefficient in the operation process of mechanical system, and ensures rotation accuracy. When high-speed ball bearings operate, a large amount of heat is generated due to friction between elements, in order to protect the structure from overheating, lubricating oil needs to be supplied to cool it. With the further increase of bearing speed, especially for the special needs of the aerospace field, the traditional cooling method gradually cannot meet the requirements, therefore, the inner flow cooling technology for bearing outer ring is developed, the traditional 'outer flow cooling' is changed into 'inner flow forced cooling' through the design of flow channel in the outer ring, so as to realize the target of improving cooling efficiency, reducing bearing temperature field and reducing the demand for lubricating oil.

[0003] The outer ring inner flow cooling technology is still in a large number of basic research stage, and the technical maturity is low, and there is no mature test method to determine the heat exchange effect of the cooling structure in the outer ring at present, and the evaluation of the heat exchange effect is also lacking. SUMMARY

[0004] The application aims to avoid the shortcomings of the prior art and provide a ball bearing outer ring heat exchange experiment method, which solves the technical problem that the cooling effect of the unconventional cooling device of the bearing outer ring cannot be determined.

[0005] To achieve the above object, the technical scheme adopted by the application is as follows: a ball bearing outer ring heat exchange experiment method, characterized in that it comprises the following steps:

[0006] First step, connecting the experiment device:

[0007] The experiment device comprises three parts of an oil supply system, a heating and temperature measuring system and an oil return system, the oil supply system comprises an oil tank, an oil supply pump, a flow sensor, a temperature sensor and a pressure sensor, the heating and temperature measuring system comprises a bearing outer ring with an internal flow channel to be measured, an inner channel heater, a temperature sensor for measuring the outer surface temperature of the outer ring and a rack for fixing the above elements, and the oil return system comprises an oil return tank and an oil return pump; the three parts of the oil supply system, the heating and temperature measuring system and the oil return system are connected by an oil conveying hose;

[0008] Second step, connecting the power supply and opening the software: connect the power supply of the experiment device, open the experiment software through the software control end, and the readings of the sensors are normal to enter the next step;

[0009] Third step, preheating the lubricating oil of the oil supply system: turn on the heater in the oil tank, set the oil supply temperature T, and stop heating after the temperature in the oil tank stabilizes to T;

[0010] Fourth step, start oil supply pump and oil return pump: adjust the output oil supply flow Q of the oil supply pump; when the liquid level in the oil return tank of the oil return system reaches one fourth of the total volume of the oil tank, start the oil return pump, and adjust the power of the oil return pump to keep the liquid level in the oil return tank stable at one fourth of the total volume of the oil tank;

[0011] Fifth step, start heating the heating wire: after the oil supply flow and temperature are stable at the set values, set the heating power to 25% W, and start heating;

[0012] Sixth step, record data: click the record data button in the software control terminal software to start recording the test data;

[0013] Seventh step, observe the temperature of the measured bearing outer ring measuring point until the average change amplitude of each measuring point is less than 0.1 degrees Celsius, and determine that the heat exchange is stable in this working condition, increase the heating power W to 50% W, and continue the test;

[0014] Eighth step, according to the heat exchange stability determination standard of the seventh step, complete the heat exchange test of heating power W of 25% W, 50% W, 75% W and 100% W under the oil supply flow and temperature;

[0015] Ninth step, end data recording and stop heating: click the record data button in the software control terminal software to end data recording; set the heating power to 0 and stop heating, continue to supply oil until the measuring points on the outer wall of the measured bearing outer ring are all below 100 degrees Celsius, stop supplying oil, wait until there is no lubricating oil accumulation in the oil return tank, stop oil return, turn off the power, and the test is completed.

[0016] Further, the lubricating oil in the oil supply system is aviation lubricating oil.

[0017] Further, the oil supply temperature T is the temperature of the lubricating oil supplied by the lubricating system of the bearing under actual working conditions; and the oil supply flow Q is one fourth of the total lubricating oil supplied by the lubricating system of the bearing under actual working conditions.

[0018] Further, the oil supply flow Q of the oil supply system ranges from 0 to 3 L / min, and the oil supply temperature T ranges from 40 to 70 degrees Celsius.

[0019] Further, the heating power W is 25% of the total heat generated by the bearing under actual working conditions; the total heat generated by the bearing under actual working conditions The calculation uses the Palmgren model for calculation, and the formula is as follows:

[0020] ,

[0021] ,

[0022] ,

[0023] ,

[0024] wherein, is the total friction torque of the rolling bearing (N x m) ; is the friction torque related to the load applied to the bearing (N x m) ; is the torque related to the type of bearing, the rotational speed and the nature of the lubricant (N x m) ; is the pitch diameter of the bearing (m) ; is the rotational speed of the bearing (r / min) ; is the kinematic viscosity of the lubricant (m 2 / s) ; is a coefficient related to the type of bearing and the lubrication method, is a coefficient related to the type of bearing and the load applied to the bearing, is the calculated load for determining the friction torque of the bearing;

[0025] Further, the temperature measuring points of the temperature sensor in the heating temperature measuring system are located on the outer wall surface of the measured bearing outer ring, and are circumferentially distributed in M temperature measuring zones, and each temperature measuring zone is axially distributed with N temperature measuring sensors, M and N are positive integers; there are M x N measuring points; the temperature measuring sensor is a PT100 temperature sensor.

[0026] Further, the oil return tank is an open oil tank in communication with the atmospheric environment, so that the oil outlet of the internal flow channel of the measured bearing outer ring is under normal atmospheric pressure, and the operating power of the oil supply pump and the oil return pump is not the same.

[0027] The flow channel heat transfer characteristic evaluation method in the heat transfer experiment process of the outer ring of the ball bearing, specifically includes that the temperature field of the outer ring is affected by three factors, which are oil supply flow, oil supply temperature and heating amount, the influence of the three factors on the temperature field is studied by using the control variable method, the temperature change curve is drawn, and the heat transfer characteristics of the flow channel are obtained.

[0028] The experimental data processing method in the heat transfer experiment process of the outer ring of the ball bearing, specifically includes that the internal flow channel of the measured bearing outer ring is symmetrically distributed relative to the oil inlet and the oil outlet, 8 heat transfer stable measuring point temperatures corresponding to two symmetrical temperature measuring zones are taken, bad points higher or lower than 20% of the average value are eliminated, and the average value is taken again as the temperature of a point on the outer surface of the outer ring; at least 4 temperatures are taken out according to the above processing method, and the temperature is plotted along the oil flow direction angle (22.5°, 67.5°, 112.5°, 157.5°) of a half circle, the temperature change trend graph of the outer surface of the measured bearing outer ring with the flow direction under different heating amounts is obtained, and the influence of heating amount on heat transfer characteristics is analyzed.

[0029] Compared with the prior art, the present invention has the following technical effects: the described ball bearing ring heat exchange test method realizes power-adjustable heating of the outer bearing ring alone, and can quantitatively obtain the steady-state temperature distribution of n measuring points on the outer wall of the outer bearing ring of the test piece under different heating and oil supply conditions (oil supply temperature and oil supply amount), as well as the internal pressure loss of the flow channel, to evaluate the cooling effect of the internal flow channel of the outer bearing ring and the multi-working condition heat exchange characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a flow chart of the present invention;

[0031] Figure 2 Schematic diagram of the heat exchange experiment principle of the present invention;

[0032] Figure 3 Schematic diagram of the heating and temperature measurement system of the present invention;

[0033] Figure 4 This is a graph showing the change trend of the outer surface temperature of the ferrule with different heating amounts as the oil flow rate is 3L / min and the oil temperature is 40°C.

[0034] In the figure: 1. Oil outlet; 2. Outer ring of the bearing with internal flow channel under test; 3. Internal flow channel heater; 4. Temperature sensor. DETAILED DESCRIPTION

[0035] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0036] In order to achieve the above object, the present invention provides the following specific implementation methods: the heat transfer experimental method of the outer ring of a ball bearing, such as Figure 1 As shown, it is characterized in that it includes the following steps:

[0037] Step 1: Connect the experimental device: Figure 2 As shown, the experimental device consists of three parts: oil supply system, heating and temperature measurement system and oil return system. The oil supply system includes oil tank, oil supply pump, flow sensor, temperature sensor and pressure sensor. The heating and temperature measurement system includes, Figure 3 As shown, the oil outlet 1 and oil inlet 5 on the back of the ring are located, the outer ring of the bearing with internal flow channel 2 to be tested, the inner channel heater 3, the temperature sensor 4 for measuring the temperature of the outer surface of the ring, and the stand for fixing the above components. The oil return system includes the oil return tank and oil return pump. The three parts of the system are connected by an oil transfer hose.

[0038] Step 2: Turn on the power and open the software: Turn on the power of the experimenter and open the experimental software. If the readings of each sensor are normal, proceed to step 3.

[0039] Third step, preheat the oil supply system: open the oil tank heater, set the oil supply temperature T, stop heating when the oil tank temperature stabilizes at T;

[0040] Fourth step, open the oil supply pump and oil return pump: adjust the output oil supply flow Q of the oil supply pump; when the oil level in the oil return tank reaches one fourth of the total volume of the oil tank, open the oil return pump and adjust the power of the oil return pump to stabilize the oil level at one fourth of the total volume of the oil tank;

[0041] Fifth step, start heating: after the oil supply flow and temperature stabilize at the required values, set the heating power to 25% W and start heating.

[0042] Sixth step, record data: click the data recording button in the software to start recording test data.

[0043] Seventh step, observe the temperature of the measured bearing outer ring measuring point until the average change amplitude of each measuring point is less than 0.1 degrees Celsius, and determine that the heat exchange is stable under this working condition. Increase the heating power to 50% W and continue the test.

[0044] Eighth step, according to the heat exchange stability determination standard of step seven, complete the heat exchange test with heating power of 25% W, 50% W, 75% W and 100% W respectively under the oil supply flow and temperature.

[0045] Ninth step, end data recording and stop heating: click the data recording button in the software to end data recording; set the heating power to 0 and stop heating. Continue to supply oil until the measuring points on the outer wall of the measured bearing outer ring are all below 100 degrees Celsius, stop oil supply, and stop oil return when there is no oil accumulation in the oil return tank. Turn off the power and the test is completed.

[0046] In this embodiment, the used lubricating oil is aviation lubricating oil.

[0047] In this embodiment, the oil supply temperature T is the temperature of the lubricating oil supplied by the lubricating system under the actual working condition of the bearing.

[0048] In this embodiment, the oil supply flow Q is one fourth of the total lubricating oil supplied by the lubricating system under the actual working condition of the bearing.

[0049] In this embodiment, the heating power W is 25% of the total heat generated by the bearing under the actual working condition, and the total heat generated by the bearing is The calculation uses the Palmgren model, and the formula is as follows:

[0050] ,

[0051] ,

[0052] ,

[0053] ,

[0054] In the formula, is the total friction torque of the rolling bearing (N x m); is the friction torque related to the load on the bearing (N x m); is the torque related to the bearing type, rotational speed and lubricating oil properties (N x m); is the pitch diameter of the bearing (m); is the rotational speed of the bearing (r / min); is the kinematic viscosity of the lubricating oil (m 2 / s); is a coefficient related to the bearing type and lubrication method, is a coefficient related to the bearing type and the load on the bearing, is the calculated load for determining the friction torque of the bearing.

[0055] In the embodiment, the temperature measuring points of the temperature sensors in the heating temperature measuring system are located on the outer wall surface of the outer ring of the measured bearing, and are circumferentially distributed in M temperature measuring zones, and each temperature measuring zone is axially distributed in N temperature measuring sensors, M and N are positive integers; there are M x N measuring points. The temperature measuring sensor is a PT100 temperature sensor.

[0056] In the embodiment, the oil return tank is an open tank in communication with the atmospheric environment, so that the lubricating oil outlet of the internal flow channel of the outer ring of the measured bearing is under normal atmospheric pressure, and therefore the operating power of the oil supply pump and the oil return pump is not the same.

[0057] As a specific scheme of the embodiment, the lubricating oil is Feima No. 2 aviation lubricating oil.

[0058] As a specific scheme of the embodiment, the outer wall surface of the outer ring of the measured bearing is circumferentially distributed in 8 temperature measuring zones, and each temperature measuring zone is axially distributed in 4 temperature measuring sensors, and there are 32 measuring points.

[0059] As a specific scheme of the embodiment, the oil supply system has an oil supply flow range of 0-3 L / min and an oil supply temperature range of 40-70°C.

[0060] As a specific scheme of the embodiment, the flow channel heat exchange characteristic evaluation method is as follows: the temperature field of the outer ring is affected by three factors, namely the oil supply flow, the oil supply temperature and the heating amount, the control variable method is used to study the influence of the three factors on the temperature field, the temperature change curve is drawn, and the heat exchange characteristic of the flow channel is obtained.

[0061] As a specific scheme of the embodiment, the experimental data processing process is as follows: in the embodiment, the internal flow channel of the ring is symmetrically distributed relative to the oil inlet and the oil outlet, two symmetric temperature measuring zones are taken, the heat exchange stable measuring point temperatures corresponding to a total of 8 working conditions are taken, the bad points higher or lower than 20% of the average value are eliminated, and the average value is taken as the temperature of a point on the outer surface of the outer ring again; in the embodiment, a total of 8 symmetric temperature measuring zones are taken, 4 temperatures are taken according to the above processing method, and the temperatures are plotted along the half-circle sliding oil flow direction angles (22.5°, 67.5°, 112.5°, 157.5°).

[0062] As a specific scheme of the embodiment, as shown in Figure 4 , a trend chart of the outer surface temperature of the ring varying with the flow direction under different heating amounts when the oil supply flow is 3L / min and the oil supply temperature is 40℃ is drawn, and the influence of the heating amount on the heat exchange characteristics is analyzed.

[0063] (1) The outer surface temperature of the ring increases along the flow direction, and basically presents a linear change;

[0064] (2) As the heating amount increases, the circumferential temperature difference of the ring increases, and the circumferential temperature uniformity decreases; the circumferential temperature difference is 10℃ when the heating amount is 500W, and the circumferential temperature difference increases to 30℃ when the heating amount is 2000W.

[0065] (3) The circumferential temperature non-uniformity easily leads to the decrease of the roundness of the ring, causes the uneven radial clearance of the bearing, and may cause the sliding of the ball, thereby affecting the safe operation of the bearing, so that the increase of the heating amount is not conducive to the safety of the bearing, and the flow supply of the inner flow of the ring needs to be designed by matching the flow of the under-ring or jet lubrication.

[0066] In the embodiment, the pressure loss of the internal flow channel of the outer ring under the atmospheric outlet condition can be analyzed through the pressure sensor in the oil supply system.

[0067] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A ball bearing outer ring heat transfer test method, characterized in that: The following steps are involved: Step 1: Connect the experimenter: The experimental device includes three parts: an oil supply system, a heating and temperature measurement system, and an oil return system. The oil supply system includes an oil tank, an oil supply pump, a flow sensor, a temperature sensor, and a pressure sensor. The heating and temperature measurement system includes an outer ring of a bearing with an internal flow channel to be measured, an oil outlet, an oil inlet, an inner flow channel heater, a temperature sensor for measuring the temperature of the outer surface of the ring, and a stand for fixing the above components. The oil return system includes an oil return tank and an oil return pump. The oil supply system, the heating and temperature measurement system, and the oil return system are connected by an oil hose. Among them, the oil outlet and oil inlet are located on the back of the outer ring of the bearing; Step 2: Turn on the power and open the software: Turn on the power of the experimenter and open the experimental software through the software control terminal. If the readings of each sensor are normal, proceed to the next step. Step 3: Preheat the lubricating oil in the oil supply system: Turn on the heater in the oil tank, set the oil supply temperature T, and stop heating after the temperature in the oil tank stabilizes at T; Step 4: Start the oil supply pump and the return oil pump: adjust the output oil flow rate Q of the oil supply pump; when the liquid level in the return oil tank of the return oil system reaches one-quarter of the total volume of the tank, start the return oil pump and adjust the return oil pump power until the liquid level in the return oil tank stabilizes at one-quarter of the total volume of the tank; Step 5: Turn on the heating wire heating: After the oil flow and temperature stabilize at the set value, set the heating power W to 25%W watts and turn on the heating; Step 6. Record data: Click the record data button in the software control terminal to start recording test data; Step 7: Observe the temperature of the outer ring of the bearing under test until the average temperature change at each measuring point is less than 0.1 degrees Celsius. This indicates that the heat exchange is stable under this working condition. Increase the heating power W to 50%W watts and continue the test. Step 8. According to the heat exchange stability certification standard in step 7, complete the heat exchange test at the oil supply flow rate, temperature, and heating power of 25%W, 50%W, 75%W, and 100%W respectively; Step 9. End data recording and stop heating: Click the record data button in the software control terminal to end data recording; set the heating power to 0, stop heating, and continue to supply oil until the temperature of the outer wall of the outer ring of the tested bearing is lower than 100 degrees Celsius. Stop supplying oil and wait until there is no oil accumulation in the return tank. Stop returning oil and turn off the power. The test is over.

2. A ball bearing outer ring heat transfer test method according to claim 1, characterized in that: The lubricating oil in the oil supply system is aviation lubricating oil.

3. A ball bearing outer ring heat transfer test method according to claim 1, characterized in that: The oil supply temperature T is the temperature of the lubricating oil supplied by the lubrication system to the bearing under actual working conditions; the oil supply flow rate Q is one quarter of the total lubricating oil supplied by the lubrication system to the bearing under actual working conditions.

4. A ball bearing outer ring heat transfer test method according to claim 3, characterized in that: The oil supply flow rate Q of the oil supply system is in the range of 0-3 L / min, and the oil supply temperature T is in the range of 40-70°C.

5. A ball bearing outer ring heat transfer test method according to claim 1, characterized in that: The heating power W is 25% of the total heat generated by the bearing under actual working conditions; the total heat generated by the bearing The calculation is based on the Palmgren model, and the formula is as follows: ， ， ， ， Where, is the total friction torque of the rolling bearing, in N×m; is the friction torque related to the load on the bearing, in N×m; is the torque related to the bearing type, speed and lubricant properties, in N×m; is the bearing pitch diameter, in m; is the bearing speed, in r / min; is the kinematic viscosity of the lubricating oil, in m 2 / s; is a coefficient related to bearing type and lubrication method, It is a coefficient related to the bearing type and the load it is subjected to. Calculated load for determining bearing friction torque.

6. A ball bearing outer ring heat transfer test method according to claim 1, characterized in that: The temperature sensor measuring points in the heating and temperature measuring system are located on the outer wall of the outer ring of the bearing to be measured, with M temperature measuring zones evenly distributed circumferentially, and N temperature measuring sensors evenly distributed axially in each temperature measuring zone, where M and N are positive integers; there are a total of M×N measuring points; the temperature measuring sensor uses a PT100 temperature sensor.

7. A ball bearing outer ring heat transfer test method according to claim 1, characterized in that: The oil return tank is an open tank connected to the atmosphere, so that the lubricating oil outlet of the internal flow channel of the outer ring of the tested bearing is at normal atmospheric pressure. The operating power of the oil supply pump and the oil return pump are different.

8. A ball bearing outer ring heat transfer test method according to any one of claims 1 to 7, characterized in that: Specifically include: The temperature field of the outer ring is affected by three factors, namely, oil flow rate, oil temperature and heating amount. The control variable method is used to study the influence of the three factors on the temperature field respectively, draw a temperature change curve, and obtain the heat transfer characteristics of the flow channel.

9. A ball bearing outer ring heat transfer test method according to any one of claims 1 to 7, characterized in that: Specifically include: The internal flow channels of the outer ring of the tested bearing are symmetrically distributed relative to the oil inlet and outlet. Two symmetrical temperature measurement areas are taken, and the heat exchange stable measurement point temperatures corresponding to a total of 8 working conditions are obtained. The bad points that are 20% higher or lower than the average value are eliminated, and the average value is taken again as the point temperature on the outer surface of the outer ring; according to the above processing method, the temperatures of at least 4 points are taken out, and the plot is drawn along the angle of the half-circle lubricating oil flow direction. The trend diagram of the change of the outer surface temperature of the outer ring of the tested bearing with the flow direction under different heating amounts is obtained, and the effect of heating amount on the heat transfer characteristics is analyzed.

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