Bearing lubrication devices, methods for relubricating bearings, and methods for constructing bearing lubrication devices.

Abstract

The invention begins with a bearing lubrication device (10) comprising a lubrication unit (12) configured to discharge grease into a space (14) between a first ring (16) and a second ring (18) of a bearing (20), and at least one temperature sensor (22) capable of measuring the temperature T of a component (34) of the bearing, and at least one control unit (24) programmed to induce the lubrication unit to discharge grease as a relubrication time span elapses. The relubrication time span is proposed to depend on (I) and / or (II), where t is time, and P is the power required to compensate for friction in the bearing or an approximation of that power. EHL It is the sum or an approximation of the sum of the power required to compensate for the friction between the rolling elements (26) of the bearing and all the rings (16, 18) of the bearing and the power required to compensate for the friction caused by the seals (28, 30) of the bearing, where is the ambient temperature, C(t) and D(t) are functions, and are held constant, where and where t chur This refers to the point in time when the bearing ends its agitation phase after it first starts operating at t=0. (I) (II)

Description

Technical Field

[0001] This invention relates to a bearing lubrication device, a method for relubricating a bearing, and a method for constructing a bearing lubrication device. Background Technology

[0002] Relubrication in lubrication systems is now typically accomplished by applying intermittent doses: small amounts every few hours. To ensure that aged grease is properly replaced, much more grease than 30% of the free volume inside the bearing is dispensed during the relubrication interval. This excessive grease usage is intended to prevent failure. Therefore, relubrication results in a near-continuous grease turbulence state, leading to high friction, energy loss, thermomechanical degradation of the grease, and reduced grease life / relubrication interval. Knowledge about grease life is rarely used in lubrication systems (in practice, it is time-based).

[0003] Grease life is determined by chemical and thermomechanical degradation. Chemical degradation (oxidation) is deterministic. Mechanical degradation is determined by the stress on the grease, which is determined by the grease's flow and flow properties. This flow is highly nonlinear. Therefore, grease life also depends on how the bearing grease "breaks in." The break-in phase is called the "churning phase." After this churning phase, the grease is stationary, and lubrication occurs primarily through the seepage of oil from the grease to the contacts. The phase in which the grease is stationary and lubrication occurs primarily through the seepage of oil from the grease is called the "seepage phase." As explained, the seepage phase begins when the churning phase ends. The timing of the start of the seepage phase can be determined by the bearing's temperature behavior.

[0004] Condition-based dosages are also known, where relubrication intervals are calculated using grease life models (based on (real-time measured) speed, temperature, and load, or based on their "best guess").

[0005] For example, in “Impact of grease churning on grease leakage, oil bleeding and grease rheology”, Tribology International 176 (2022) 107926 (hereinafter referred to as “Reference 1”) and “Thermo-mechanical aging during churning in grease lubricated bearings and its impact on grease life”, Tribology International Volume 181, March 2023, 108248 (hereinafter referred to as “Reference 2”). Summary of the Invention

[0006] The problem addressed by the present invention is, in particular, improving the efficiency of bearing lubrication. According to the invention, this objective is achieved by the features of claim 1, claim 9, and claim 10, while advantageous and further embodiments of the invention can be derived from the dependent claims.

[0007] The present invention begins with a bearing lubrication device comprising a lubrication unit configured to discharge grease into the space between the first and second races of a bearing, at least one temperature sensor capable of measuring the temperature T of the bearing components, and at least one control unit programmed to cause the lubrication unit to discharge grease when a relubrication time span has elapsed.

[0008] The proposed relubrication time span depends on and / or Where t is time, and P is the power required to compensate for bearing friction or an approximation of that power. EHL It is the sum of, or an approximation of, the power required to compensate for friction between the rolling elements of the bearing and all the bearing races, and the power required to compensate for friction caused by the bearing seals. Let C(t) be the ambient temperature, and D(t) be functions that satisfy the following conditions: and and and and and ,in and , where t chur This is the point in time when the bearing ends its agitation phase after it first starts operating at t=0. This method can improve bearing lubrication efficiency.

[0009] Specifically, the control unit is programmed to determine the relubrication time span, and preferably, the control unit is programmed to calculate the relubrication time span.

[0010] Furthermore, it is suggested that the larger E and / or S are, the shorter the relubrication time span. Therefore, if necessary, only a larger amount of grease needs to be used for lubrication. This also leads to improved bearing reliability and reduced bearing friction.

[0011] Advantageously, Where T0 is the first constant temperature value, T A This is the second constant temperature value. In this way, the thermal effect can be adjusted.

[0012] Specifically, it can satisfy or .

[0013] In addition, it was proposed and / or Preferably and / or More preferably and / or The most preferred option and / or In this way, good accuracy in the relubrication time span can be achieved.

[0014] Advantageously, the control unit is programmed to calculate the length of the relubrication time span, wherein the control unit is programmed to use a grease life model to calculate an approximation of the relubrication time span and multiply this approximation by a factor that is a function of E and / or S. This allows for a simple and efficient determination of the relubrication time span.

[0015] Furthermore, it is proposed that the bearing lubrication device includes at least one measuring unit and / or at least one measuring unit constituting a means for measuring the frictional torque of the bearing, and at least one measuring unit constituting a means for measuring the load of the bearing. Through this measurement, an input for calculating E can be obtained.

[0016] Advantageously, the control unit is programmed to calculate an approximation of the power required to compensate for friction between the bearing rolling elements and all bearing races using a bearing friction model. Therefore, a significant contribution to the calculation of E can be achieved relatively easily. Specifically, the control unit is programmed to calculate an approximation of the power required to compensate for friction caused by the bearing seals.

[0017] Furthermore, it was proposed that the control unit be programmed to calculate P using the average cooling coefficient. In this way, torque measurement can be omitted.

[0018] In addition, a device including a bearing lubrication device and a bearing is proposed.

[0019] Furthermore, a method for relubricating bearings is proposed, wherein grease is discharged into the space between the first and second races of the bearing during a relubricating time span, wherein during the time span... and / or It is calculated in real time, and at time point t s When satisfied and / or At that time, the discharge of lubricating grease is stopped, of which a predetermined amount E critical and / or the pre-ordered quantity S critical These values ​​are stored separately in the control unit, where t is time, T is the temperature of the bearing components, and P is the power required to compensate for friction in the bearing, or an approximation of that power. EHL It is the sum of, or an approximation of, the power required to compensate for friction between the rolling elements and all the rings of the bearing and the power required to compensate for friction caused by the bearing seals. The ambient temperature is C(t), and C(t) and D(t) are functions, where t b It refers to a specific point in time, at the start of a time span. This method improves bearing lubrication efficiency, specifically leading to longer bearing life and lower grease consumption.

[0020] Advantageously, Where T0 is the first constant temperature value, T A This is the second constant temperature value. In this way, the thermal effect can be adjusted.

[0021] Specifically, it can satisfy or .

[0022] Furthermore, a method for constructing a bearing lubrication device is proposed, comprising a set of experiments in which different strategies for dispensing grease to the bearing are applied in each experiment, and quantities E and / or S are calculated for each experiment. A strategy for dispensing is implemented in the bearing lubrication device, for which at least some function F of E and / or S has a minimum value compared to the remaining strategies. and / or Where t is time, T is the temperature of the bearing component, and P is the power required to compensate for friction in the bearing, or an approximation of that power. EHL It is the sum of, or an approximation of, the power required to compensate for friction between the rolling elements and all the rings of the bearing and the power required to compensate for friction caused by the bearing seals. Let C(t) be the ambient temperature, and D(t) be functions that satisfy the following conditions: and and and and and ,in and , where t chur This refers to the point in time when the bearing ends its agitation phase after it first starts operating at t=0. This method can improve bearing lubrication efficiency.

[0023] Specifically, this strategy is implemented in the bearing lubrication system by programming the control unit to execute the strategy.

[0024] In particular, the strategy could be to lubricate after a certain time interval.

[0025] Advantageously, Where T0 is the first constant temperature value, T A This is the second constant temperature value. In this way, the thermal effect can be adjusted.

[0026] Specifically, it can satisfy or .

[0027] In addition, it was proposed and / or Preferably and / or More preferably and / or The most preferred option and / or Therefore, good accuracy of the strategy can be achieved. Attached Figure Description

[0028] Further advantages will be seen in the following description of the accompanying drawings. Examples of embodiments of the invention are illustrated in the drawings. The drawings, description, and claims contain a number of combined features. Those skilled in the art will also readily consider the features individually and combine them to form further useful combinations.

[0029] Figure 1 A schematic half-sectional view of a device having a bearing lubrication device and a bearing according to the present invention is shown.

[0030] Figure 2 A graph showing the life of standardized grease is provided, and

[0031] Figure 3 Another graph showing the standardized grease life is presented. Detailed Implementation

[0032] Figure 1 A half-section of a device having a bearing lubrication device 10 and a bearing 20 is shown. The bearing is a ball bearing. The bearing could also be a different type of rolling bearing. The bearing lubrication device includes a lubrication unit 12 configured to discharge grease into a space 14 between a first race 16 and a second race 18 of the bearing 20. The first race 16 is an outer race, and the second race 18 is an inner race. To discharge grease into the space 14, the lubrication unit 12 includes a pump (not shown) that pumps grease from the lubrication unit 12 through a through-hole 36 in the race 16 into the space 14. This lubricates the movement of the rolling element 26 of the bearing 20 relative to the races 16, 18. Furthermore, the bearing 20 includes a first seal 28 that seals the space 14 at a first axial end of the bearing 20. Additionally, the bearing 20 includes a second seal 30 that seals the space 14 at a second axial end of the bearing 20.

[0033] The bearing lubrication device 10 includes a temperature sensor 22, which measures the temperature T of the bearing component 34. Component 34 is the first race 16. Furthermore, the bearing lubrication device 10 includes a control unit 24, which is programmed to cause the lubrication unit 12 to discharge grease into the space 14 through the through-hole 36 when the relubrication time span has elapsed.

[0034] At time t=0, the bearing begins operation for the first time. This means that the agitation phase of bearing operation also begins at t=0. During this phase, the bearing grease is agitated by the rolling element 26. The agitation phase ends at... The relubrication time span depends on and / or Here, t is time, and P is the power required to compensate for friction in the bearing, or an approximation of that power. EHL It is the sum of, or an approximation of, the power required to compensate for the friction between the rolling element 26 of the bearing and all the bearing races 16, 18, and the power required to compensate for the friction caused by the bearing seals 28, 30. Let C(t) be the ambient temperature surrounding the device, and let C(t) and D(t) be functions that satisfy the following conditions: and and and and and ,in and Alternatively, the following situations may occur: and / or Preferably and / or More preferably and / or The most preferred option and / or It can satisfy... and / or T0 is the reference temperature, and it can be 40°C. A It is the so-called Arrhenius temperature, which can be 15°C. The thermal aspect, including mechanical degradation, can be selected.

[0035] Furthermore, the bearing lubrication device includes a measuring unit 32, which is configured to measure the frictional torque of the bearing. The measuring unit 32 is also configured to measure the load on the bearing and the rotational speed of the bearing.

[0036] Control unit 24 is programmed to calculate the length of the relubrication time span. The larger E and / or S are, the smaller the determined relubrication time span. The control unit is programmed to use a grease life model (see, for example, "Rolling bearings," October 2018, SKF catalog, pp. 112-113, publication number PUB BU / P1 17000 / 1 EN) to calculate an approximation of the relubrication time span and multiply this approximation by a factor that is a function of E and / or S, giving the final result for the relubrication time span. The approximation of the relubrication time span is... L 50 It refers to the amount of time during which the grease no longer lubricates the bearing, and the likelihood of failure. This factor, as already described, is determined by E and / or S. First, calculate the energy density. V g It is the volume of the bearing's grease. Figure 2 This was obtained through experiments, which involved measuring the grease life and simultaneously calculating the E value of the bearings in the corresponding experiments. V . Figure 2 Normalized grease life is the measured grease life divided by the calculated L. 50 . Figure 2 Figure 5(a) of Reference 2 describes how it can be obtained precisely through experiments. Figure 2 The dashed lines in the diagram represent functions that can be obtained by fitting the experimental data shown: depending on E. V The normalized grease life. This function is stored in the control unit. For bearing 20, the calculated E... V It is placed into this function: thus obtaining a value: this value is multiplied by (Here L) 50 (These are calculated values), which produce the final result for the relubrication time span of bearing 20. The described calculations are performed by control unit 24.

[0037] Control unit 24 is programmed to calculate P via a bearing friction model. EHL This bearing friction model can be found in "Rolling bearings" from the August 2013 issue of the SKF catalog, publication number PUB BU / P1 10000 / 2 EN. The equations used for this calculation are also included in Section 2.7 of Reference 1. Using these equations and the bearing load measured by measuring unit 32, the calculated P can be obtained. EHL The required friction torque. Then, this friction torque is multiplied by the rotational speed measured by measuring unit 32: this produces P. EHL The measured frictional torque is multiplied by the measured rotational speed to obtain P. Using P and P... EHL E can be calculated by time integration, see the equation mentioned.

[0038] In some cases, frictional torque cannot be measured. Then, the average cooling factor W can be used as a reference. s P is calculated, see Section 2.7 of Reference 1, and is stored in Control Unit 24 and obtained as described in Section 2.7 of Reference 1. s The method of cooling the bearing by balancing the thermal energy with the environment surrounding the bearing is described. P can be calculated from the temperature measured during the stirring phase, see equation (5) in reference 1: ,in W can be calculated based on data from the bleeding phase of the bearing. s : . It refers to the ambient temperature, specifically the temperature around the bearing (used for measurement). (The sensor is not shown).

[0039] The control unit is programmed to use the measured temperature T and the measured To calculate S. Using S, the control unit calculates... ,in Where r0 is the outer ring radius of the bearing, B is the bearing width, and h cr It is the combined (convective and radiative) heat transfer coefficient (see (4) of reference 2). Figure 3 Normalized grease life is the measured grease life divided by the calculated L. 50 . Figure 3 It is Figure 5(b) from reference 2. Figure 3 This was obtained through experiments, which involved measuring the life of the lubricating grease and simultaneously calculating the S-value of the bearings in the corresponding experiments. QV Reference 2 describes how to accurately obtain [the required data] experimentally. Figure 3 . Figure 3The dashed lines in the diagram represent functions that can be obtained by fitting the experimental data shown: depending on S QV The normalized grease life. This function is stored in the control unit. For bearing 20, the calculated S... QV Place it in this function: obtain a value through this function: multiply this value by (Here L) 50 (This is a calculated value), which produces the final result of the relubrication time span, which is used for bearing 20 in case the relubrication time span is not calculated using E, and only S is used for the calculation.

[0040] The relubrication time span begins at the end of the agitation phase. Relubrication is then repeated periodically after a further relubrication time span of the same length. Temperature T is controlled by a control unit at least during the break-in phase and preferably... Records were made during the break-in period.

[0041] All the calculations described are performed by the control unit 24.

[0042] exist Figure 2 and Figure 3 In this context, the measured grease life is the amount of time that the grease no longer lubricates the bearing, and it includes the probability of failure. . Figure 2 and 3 The effect of agitation is shown. Here, many bearings operate under exactly the same conditions. However, due to the "chaotic nature" of grease lubrication, each bearing exhibits different break-in characteristics.

[0043] It should be noted that choosing D(t)=0 also works within the scope of this invention.

[0044] use Figure 1 The apparatus shown can execute a procedure for relubricating bearings, which differs from the procedure described above and another embodiment of the invention. This process is executed by a control unit. During this process, grease is discharged into the space 14 between the first and second races 16 and 18 of the bearing during relubricating intervals. and / or Real-time calculation, and at time point t s Stop grease discharge; at this point, the desired effect is achieved. and / or Of which the predetermined quantity E critical and / or the pre-ordered quantity S critical They are stored separately in control unit 24, where t b This is the starting point of the relubrication interval. The length of the time span between two relubrication intervals can be stored in the control unit.

[0045] Another embodiment of the present invention, namely the process, can also be used Figure 1 The device shown in the diagram, wherein for this embodiment of the invention, the programming of the control unit 24 differs from the programming in the first embodiment of the invention. The program is a program for constructing the bearing lubrication device 10, wherein a set of experiments is conducted, in which different strategies are applied to quantitatively add grease to the bearing 20 in each experiment, and for each experiment, quantities E and / or S are calculated, and a quantitative strategy is implemented in the bearing lubrication device, for which a certain function F, at least depending on E and / or S, has a minimum value compared to the remaining strategies. Quantities E and S are as described above. The function F can be, for example, F(E) = E or F(S) = S. In another example, F can depend on both E and S. One strategy for adding grease to the bearing can be each time after a certain time span t... lub A certain amount of grease is added to the bearing. Different strategies can be employed, for example, by using different t... lub The values ​​and / or the amounts of grease vary from one another. The optimal strategy is implemented by programming the control unit 24.

[0046] For all the embodiments described in this invention, premature bearing failure can be prevented by using the same amount of grease required for other bearings of the same type and under the same conditions and with the same history. Furthermore, using this invention and the described embodiments, less grease can be dispensed to bearings that require less grease than other bearings of the same type and under the same conditions and with the same history. Therefore, grease savings are also possible, which reduces friction and thus energy consumption. The dispensing method of this invention and all embodiments reduces the mechanical degradation of the grease in the bearing, resulting in reduced dispensing time and a smaller required grease volume. Metered dispensing minimizes grease degradation, thus improving bearing reliability.

[0047] This invention is both a condition monitoring tool for lubrication systems and a relubrication strategy tool for lubrication systems.

[0048] List of reference numerals in the attached diagram:

[0049] 10 Bearing lubrication device 12 Lubrication unit 14 space 16 Ring toss 18 Ring toss 20 bearings 22 Temperature sensor 24 Control device 26 Rolling elements 28 Seals 30 Seals 32 Measurement unit 34 part 36 Through hole

Claims

1. A bearing lubrication device (10) comprising a lubrication unit (12), at least one temperature sensor (22), and at least one control unit (24), said lubrication unit (12) being configured to discharge grease into a space (14) between a first race (16) and a second race (18) of a bearing (20), said at least one temperature sensor (22) being capable of measuring the temperature T of a component (34) of said bearing, and said at least one control unit (24) being programmed to cause the lubrication unit to discharge grease after a relubrication time span. Its features are, The relubrication time span depends on and / or Where t is time, and P is the power required to compensate for friction in the bearing, or an approximation of that power. EHL It is the sum or an approximation of the power required to compensate for the friction between the rolling elements (26) of the bearing and all the bearing races (16, 18) and the power required to compensate for the friction caused by the bearing seals (28, 30). Let C(t) be the ambient temperature, and D(t) be functions that satisfy the following conditions: and and and and and ,in and , where t chur It is the point in time when the bearing ends its agitation phase after it first starts running at t=0.

2. The bearing lubrication device according to claim 1, Its features are, The control unit (24) is programmed to determine the relubrication time span, wherein the larger E and / or S is, the smaller the determined relubrication time span.

3. The bearing lubrication device according to claim 1 or claim 2, and / or Where T0 is the first constant temperature value, T A It is the second constant temperature value.

4. The bearing lubrication device according to at least one of the preceding claims, characterized in that, and / or .

5. The bearing lubrication device according to at least one of the preceding claims, Its features are, The control unit (24) is programmed to calculate the length of the relubrication time span, wherein the control unit is programmed to use a grease life model to calculate an approximation of the relubrication time span and multiply the approximation by a factor that is a function of E and / or S.

6. The bearing lubrication device according to at least one of the preceding claims, Its features At least one measuring unit (32) configured to measure the frictional torque of a bearing, and / or at least one measuring unit (32) measuring the load on the bearing.

7. The bearing lubrication device according to at least one of the preceding claims, Its features are, The control unit (24) is programmed to calculate an approximate value of the power required to compensate for the friction between the rolling element (26) of the bearing and all the raceways (16, 18) of the bearing by means of a bearing friction model.

8. The bearing lubrication device according to at least one of the preceding claims, Its features are, The control unit (24) is programmed to calculate P by means of the average cooling coefficient.

9. A method for relubricating a bearing (20), wherein, Grease is discharged into the space (14) between the first (16) and second (18) rings of the bearing during the relubrication time span, wherein during the time span and / or It is calculated in real time, and at time point t s When satisfied and / or The discharge of lubricating grease is stopped at a certain time, wherein the predetermined quantity E critical And / or the predetermined quantity S critical These values ​​are stored separately in the control unit (24), where t is time, T is the temperature of the component (34) of the bearing, and P is the power required to compensate for friction in the bearing or an approximation of that power. EHL It is the sum or an approximation of the power required to compensate for the friction between the rolling element (26) of the bearing and all the rings (16, 18) of the bearing and the power required to compensate for the friction caused by the seals (28, 30) of the bearing. The ambient temperature is C(T) and D(T) are functions, where t b It is the point in time at which the time span begins.

10. A method for constructing a bearing lubrication device (10), wherein a set of experiments is conducted, wherein in each experiment different strategies for dispensing grease to a bearing (20) are applied, and for each experiment a quantity E and / or a quantity S is calculated, and in the bearing lubrication device a strategy for dispensing in the strategies is implemented, for which a certain function F of at least E and / or S has a minimum value compared with the remaining strategies, wherein and / or Where t is time, T is the temperature of the bearing components, and P is the power required to compensate for friction in the bearing, or an approximation of that power. EHL It is the sum or an approximation of the power required to compensate for the friction between the rolling element (26) of the bearing and all the rings (16, 18) of the bearing and the power required to compensate for the friction caused by the seals (28, 30) of the bearing. Let C(t) be the ambient temperature, and D(t) be functions that satisfy the following conditions: and and and and and ,in and ,in, t chur It is the point in time when the bearing ends its agitation phase after it first starts running at t=0.

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