A method and system for analyzing the thermal elastohydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer

Abstract

The invention relates to the technical field of RV reducers, and discloses a method and system for analyzing the thermal elastohydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer. The method comprises: obtaining data of a cycloidal pinwheel of an RV reducer, and constructing a non-Newtonian thermal elastohydrodynamic lubrication model for a rough surface of the cycloidal pinwheel; assigning initial values ​​to an oil film pressure value and a temperature using the data of the cycloidal pinwheel, and assigning an initial value to an oil film thickness of the cycloidal pinwheel using an empirical formula; constructing a function-based rough surface model of the cycloidal pinwheel; obtaining the oil film thickness and viscosity according to the non-Newtonian thermal elastohydrodynamic lubrication model for the rough surface of the cycloidal pinwheel and the rough surface model of the cycloidal pinwheel; obtaining a final pressure value and temperature value of the oil film using the non-Newtonian thermal elastohydrodynamic lubrication model for the rough surface of the cycloidal pinwheel, and analyzing the lubrication characteristics of the cycloidal pinwheel in combination with the oil film thickness, the final oil film temperature and the oil film pressure value. The invention can improve the transmission efficiency and transmission accuracy of the cycloidal pinwheel, and reduce wear at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of RV reducers, and in particular to a method and system for analyzing the thermal elastohydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer. Background Art

[0002] RV transmission is a newly emerging transmission. It is developed on the basis of traditional pin-cycloid planetary transmission. It not only overcomes the shortcomings of general pin-cycloid transmission, but also has a series of advantages such as small size, light weight, large transmission ratio range, long life, stable accuracy, high efficiency, and smooth transmission. It has received extensive attention at home and abroad. The pin-cycloid meshing characteristics of RV reducer are the key to determining the transmission accuracy of RV reducer and the stiffness of robot system. The load distribution and actual meshing speed of multi-tooth meshing transmission system in RV transmission are complex. When analyzing the lubrication characteristics of RV reducer, the influence of multiple factors must be considered. Cycloid pinwheel transmission mechanism is an important part of RV reducer. Under high-speed and heavy-load conditions, the lubrication characteristics of its meshing process have a very important influence on the transmission accuracy, transmission efficiency and service life of RV reducer. Most of the existing technologies judge whether the lubrication state is abnormal by installing display devices such as diodes. When the display device ages or fails, it will lead to inaccurate judgment, and the factors affecting the lubrication state cannot be obtained, so it is impossible to improve the cycloid pinwheel according to the influencing factors, which ultimately leads to low transmission efficiency and accuracy of the cycloid pinwheel and large wear of the cycloid pinwheel.

[0003] The prior art discloses an RV reducer and a display method for displaying the lubrication status of cycloidal teeth and pin teeth, comprising an RV reducer body and multiple oscillation circuits, wherein the RV reducer body comprises a cycloidal wheel and a pin tooth housing, the cycloidal wheel is provided with multiple cycloidal teeth, the pin tooth housing is provided with multiple pin teeth, the oscillation circuits are consistent in number with the pin teeth, one end of the pin teeth is connected to one end of the oscillation circuit in a one-to-one correspondence, and the other ends of all the oscillation circuits are connected to the cycloidal wheel, the oscillation circuit comprises a display device, and the lubrication status between the pin teeth and the cycloidal teeth is judged according to the display status of the display device. The present invention determines the existence state of the lubricating oil film between the cycloid teeth and the pin teeth by means of circuit oscillation, and can directly express the lubrication characteristics of the meshing of the cycloid teeth and the pin teeth of the RV reducer through a display device. The prior art determines whether the lubrication state is abnormal by installing display devices such as light-emitting diodes or ordinary diodes. When the display device ages or fails, inaccurate judgment will result, and factors affecting the lubrication state cannot be obtained, so that the cycloid pin wheel cannot be improved according to the influencing factors, which ultimately leads to low transmission efficiency and precision of the cycloid pin wheel and greater wear of the cycloid pin wheel. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method and system for analyzing the thermal elastic-hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer. The present invention can improve the accuracy of judging the lubrication state, improve the transmission efficiency and precision of the cycloidal pinwheel, and reduce wear.

[0005] In order to achieve the above object, the present invention provides a method for analyzing the thermal elastic-hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer, comprising:

[0006] Step S1: acquiring first data of the RV reducer, wherein the first data includes meshing point data, tooth profile modification parameters, roughness and grease parameters of the cycloid pinwheel;

[0007] Step S2: constructing a non-Newtonian thermal elastohydrodynamic lubrication model for the rough surface of the cycloid pinwheel;

[0008] Step S3: using the first data to assign initial values ​​to the pressure value and the viscosity of the oil film respectively, taking the average value of the temperature field as the initial temperature value, and using an empirical formula to assign an initial value to the oil film thickness of the cycloid pinwheel;

[0009] Step S4: Build based on A cycloidal pinwheel rough surface model of the function, using the cycloidal pinwheel rough surface model to extract the rough surface features of the cycloidal pinwheel, inputting the rough surface features into the cycloidal pinwheel rough surface non-Newtonian thermal elastic hydrodynamic lubrication model, and obtaining the oil film thickness and viscosity of the cycloidal pinwheel;

[0010] Step S5: using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloid pinwheel to obtain a new oil film pressure value;

[0011] Step S6: using the first convergence condition to determine whether the new oil film pressure value converges, if so, taking the new pressure value as the final pressure value, otherwise returning to step S3 to iterate until convergence, and taking the converged oil film pressure value as the final oil film pressure value;

[0012] Step S7: using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloid pinwheel to obtain a new oil film temperature;

[0013] Step S8: using the second convergence condition to determine whether the new oil film temperature converges, if so, taking the new oil film temperature as the final temperature, otherwise returning to step S3 to iterate until convergence, and taking the converged oil film temperature as the final oil film temperature;

[0014] Step S9: Analyze the influence of meshing point data of different rough surfaces and different cycloidal gear tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel in combination with the final oil film pressure value, the final oil film temperature and the oil film thickness; analyze the oil film characteristics of the meshing point in combination with the final oil film pressure value and the oil film thickness, and obtain the poor lubrication area, modification method and modification amount of the cycloidal pinwheel during the meshing transmission process.

[0015] Furthermore, the non-Newtonian thermal elastic hydrodynamic lubrication model of the rough surface of the cycloidal pin wheel in step S2 is based on the Ostwald rheological model, the energy field equation, the meshing points at different positions of the cycloidal pin wheel, the cycloidal wheel shaping amount and shaping method.

[0016] Furthermore, the non-Newtonian thermal elastic hydrodynamic lubrication model of the rough surface of the cycloid pinwheel in step S2 is determined by the following formula:

[0017]

[0018] in, represents the dimensionless pressure, Indicates the oil film thickness, Indicates viscosity, represents the density, Indicates the suction speed, Indicates temperature, represents the Hertzian contact half-width, represents the maximum Hertzian contact force, express The value of the previous node in the flow direction, represents the coefficient of the Reynolds equation, represents the elastic deformation stiffness coefficient, represents the number of grid layers, Indicates the node number, The value range is , Indicates the number of oil film nodes at the meshing point, represents the characteristic scale, represents the fractal dimension, Represents the frequency index.

[0019] Further, the empirical formula in step S3 is determined by the following formula:

[0020]

[0021] in, Indicates the oil film thickness, represents the equivalent radius of curvature, represents the dimensionless material parameters, Represents load per unit length.

[0022] Furthermore, in step S6, the first convergence condition is that the difference between the new oil film pressure value and the oil film pressure value of the previous iteration is within between.

[0023] Furthermore, the iteration in step S6 uses a multi-grid method and a V cycle; the oil film pressure value is divided into five layers in the vertical direction, and the number of grid nodes in each layer is different and increases with the increase of the number of layers; the oil film pressure value is iterated in the first layer The oil film pressure value is adopted in the oil film high pressure area. The dipole iteration method is used in the low pressure area of ​​the oil film. Iteration method, The bipolar iteration method and the The iteration method uses the same iteration coefficient.

[0024] Furthermore, the number of grid nodes in each layer is: 9 in the first layer, 17 in the second layer, 33 in the third layer, 65 in the fourth layer, and 129 in the fifth layer.

[0025] Furthermore, the The bipolar iteration method and the The iteration coefficient used in the iteration method is Any value in .

[0026] Furthermore, the second convergence condition in step S8 is that the difference between the new oil film temperature and the oil film temperature of the previous iteration is within between.

[0027] In addition, to achieve the above-mentioned purpose, the present invention also provides a cycloidal pinwheel thermal elastohydrodynamic lubrication characteristic analysis system for an RV reducer, comprising:

[0028] A first acquisition module: used to acquire first data of the RV reducer, wherein the first data includes meshing point data, tooth profile modification parameters, roughness and grease parameters of the cycloid pinwheel;

[0029] Model building module: used to build a non-Newtonian thermal elastic-hydrodynamic lubrication model for the rough surface of a cycloidal pinwheel;

[0030] An initial value assignment module is used to assign initial values ​​to the pressure value and the viscosity of the oil film respectively using the first data, take the average value of the temperature field as the initial temperature value, and assign an initial value to the oil film thickness of the cycloid pinwheel using an empirical formula;

[0031] The second acquisition module: used to build A cycloidal pinwheel rough surface model of the function, using the cycloidal pinwheel rough surface model to extract the rough surface features of the cycloidal pinwheel, inputting the rough surface features into the cycloidal pinwheel rough surface non-Newtonian thermal elastic hydrodynamic lubrication model, and obtaining the oil film thickness and viscosity of the cycloidal pinwheel;

[0032] The third acquisition module is used to obtain a new oil film pressure value using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloid pinwheel;

[0033] A first judgment module: used to judge whether the new oil film pressure value converges using the first convergence condition, and if so, taking the new pressure value as the final pressure value; otherwise, returning to step S3 to iterate until convergence, and taking the converged oil film pressure value as the final oil film pressure value;

[0034] A fourth acquisition module: used for acquiring a new oil film temperature by using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloidal pinwheel;

[0035] The second judgment module is used to judge whether the new oil film temperature converges by using the second convergence condition. If converged, the new oil film temperature is used as the final temperature. Otherwise, the process returns to step S3 to iterate until converged, and the converged oil film temperature is used as the final oil film temperature.

[0036] Analysis module: used to analyze the influence of meshing point data of different rough surfaces and different cycloidal gear tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel in combination with the final oil film pressure value, the final oil film temperature and the oil film thickness, and to analyze the oil film characteristics of the meshing point in combination with the final oil film pressure value and the oil film thickness, so as to obtain the poor lubrication area, modification method and modification amount of the cycloidal pinwheel in the meshing transmission process.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] The present invention constructs a non-Newtonian thermal elastohydrodynamic lubrication model for the rough surface of a cycloidal pinwheel and a rough surface model of the cycloidal pinwheel, uses the non-Newtonian thermal elastohydrodynamic lubrication model for the rough surface of the cycloidal pinwheel to obtain the oil film pressure value and temperature, uses the rough surface model of the cycloidal pinwheel to obtain the oil film thickness, combines the oil film pressure value, oil film temperature and oil film thickness to analyze the influence of meshing point data of different rough surfaces and different cycloidal wheel tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel, combines the final oil film pressure value and oil film thickness to analyze the oil film characteristics of the meshing point, and obtains the poor lubrication area, modification method and modification amount of the cycloidal pinwheel in the meshing transmission process, thereby improving the transmission efficiency and transmission accuracy of the cycloidal pinwheel and reducing wear at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a flow chart of a method for analyzing the thermal elastohydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to an embodiment of the present invention;

[0040] Figure 2 It is a block diagram of a thermal elastohydrodynamic lubrication characteristic analysis system for a cycloidal pinwheel of an RV reducer according to an embodiment of the present invention;

[0041] Figure 3 It is a cycloidal wheel single tooth profile diagram of a method for analyzing the thermal elastohydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to an embodiment of the present invention;

[0042] Figure 4 It is a fractal contour diagram of pin teeth with different roughness magnified 1000 times in a method for analyzing the thermal elastohydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to an embodiment of the present invention;

[0043] Figure 5 It is a fractal contour diagram of cycloidal wheels with different roughness magnified 1000 times in a method for analyzing the thermal elastohydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to an embodiment of the present invention;

[0044] Figure 6 The oil film thickness and pressure diagram of the meshing point of the cycloidal pinwheel of an RV reducer according to the embodiment of the present invention is not considered in the method for analyzing the thermal elastohydrodynamic lubrication characteristics of the cycloidal pinwheel;

[0045] Figure 7 The oil film thickness and pressure at the meshing point of the cycloid pinwheel when Ra=0.01 of a method for analyzing the thermal elastohydrodynamic lubrication characteristics of a cycloid pinwheel of an RV reducer according to an embodiment of the present invention;

[0046] Figure 8 It is a temperature field change of the meshing point of the cycloidal pinwheel when Ra=0.01 of a method for analyzing the thermal elastic-hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to an embodiment of the present invention;

[0047] Fig. 9 It is an analysis method of thermal elastic-hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to an embodiment of the present invention, wherein Ra=0.01, the oil film thickness and pressure of the meshing point 4 of the cycloidal pinwheel during negative displacement modification. DETAILED DESCRIPTION

[0048] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0049] Embodiment 1

[0050] like Figure 1 As shown, a method for analyzing the thermal elastic-hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to a preferred embodiment of the present invention includes:

[0051] Step S1: acquiring first data of the RV reducer, the first data including meshing point data, tooth profile modification parameters, roughness and grease parameters of the cycloid pinwheel;

[0052] Step S2: constructing a non-Newtonian thermal elastohydrodynamic lubrication model for the rough surface of the cycloid pinwheel;

[0053] Step S3: using the first data to assign initial values ​​to the pressure value and the viscosity of the oil film respectively, taking the mean value of the temperature field as the initial temperature value, and using an empirical formula to assign an initial value to the oil film thickness of the cycloid pinwheel;

[0054] Step S4: Build based on The rough surface model of the cycloidal pinwheel based on the function is used to extract the rough surface features of the cycloidal pinwheel, and the rough surface features are input into the non-Newtonian thermal elastic hydrodynamic lubrication model of the cycloidal pinwheel rough surface to obtain the oil film thickness and viscosity of the cycloidal pinwheel;

[0055] Step S5: using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloidal pinwheel to obtain a new oil film pressure value;

[0056] Step S6: using the first convergence condition to determine whether the new oil film pressure value converges, if so, taking the new pressure value as the final pressure value, otherwise returning to step S3 to iterate until convergence, and taking the converged oil film pressure value as the final oil film pressure value;

[0057] Step S7: using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloid pinwheel to obtain a new oil film temperature;

[0058] Step S8: using the second convergence condition to determine whether the new oil film temperature converges, if so, taking the new oil film temperature as the final temperature, otherwise returning to step S3 to iterate until convergence, and taking the converged oil film temperature as the final oil film temperature;

[0059] Step S9: Analyze the influence of meshing point data of different rough surfaces and different cycloidal gear tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel in combination with the final oil film pressure value, the final oil film temperature and the oil film thickness; analyze the oil film characteristics of the meshing point in combination with the final oil film pressure value and the oil film thickness, and obtain the poor lubrication area, modification method and modification amount of the cycloidal pinwheel during the meshing transmission process.

[0060] In this embodiment, a non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of a cycloidal pinwheel and a rough surface model of a cycloidal pinwheel are constructed, and the oil film pressure value and temperature are obtained by using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloidal pinwheel, and the oil film thickness is obtained by using the rough surface model of the cycloidal pinwheel. The influence of the meshing point data of different rough surfaces and different cycloidal wheel tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel is analyzed in combination with the oil film pressure value, oil film temperature and oil film thickness. The oil film characteristics of the meshing point are analyzed in combination with the final oil film pressure value and oil film thickness, and the lubrication poor area, modification method and modification amount of the cycloidal pinwheel in the meshing transmission process are obtained, thereby improving the transmission efficiency and transmission accuracy of the cycloidal pinwheel and reducing wear at the same time.

[0061] Embodiment 2

[0062] like Figure 1 As shown, a method for analyzing the thermal elastic-hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to a preferred embodiment of the present invention includes:

[0063] Step S1: acquiring first data of the RV reducer, the first data including meshing point data, tooth profile modification parameters, roughness and grease parameters of the cycloid pinwheel;

[0064] This embodiment takes the RV-40E reducer as a research example, wherein the parameters of the RV-40E reducer are shown in the following table:

[0065]

[0066] The meshing point data of the cycloid pinwheel are shown in the following table:

[0067]

[0068] The grease parameters are shown in the following table:

[0069]

[0070]

[0071] Among them, the cycloid gear tooth profile modification parameters are shown in the following table:

[0072]

[0073] Step S2: constructing a non-Newtonian thermal elastohydrodynamic lubrication model for the rough surface of the cycloid pinwheel;

[0074] In this embodiment, the non-Newtonian thermal elastic hydrodynamic lubrication model of the rough surface of the cycloidal pinwheel is based on the Ostwald rheological model, the energy field equation, the meshing points at different positions of the cycloidal pinwheel, the cycloidal wheel shaping amount and shaping method. The non-Newtonian thermal elastic hydrodynamic lubrication model of the rough surface of the cycloidal pinwheel is determined by the following formula:

[0075]

[0076] in, represents the dimensionless pressure, Indicates the oil film thickness, Indicates viscosity, represents the density, Indicates the suction speed, Indicates temperature, represents the Hertzian contact half-width, represents the maximum Hertzian contact force, express The value of the previous node in the flow direction, represents the coefficient of the Reynolds equation, represents the elastic deformation stiffness coefficient, represents the number of grid layers, Indicates the node number, The value range is , Indicates the number of oil film nodes at the meshing point, represents the characteristic scale, represents the fractal dimension, Represents the frequency index.

[0077] Step S3: using the first data to assign initial values ​​to the pressure value and the viscosity of the oil film respectively, taking the mean value of the temperature field as the initial temperature value, and using an empirical formula to assign an initial value to the oil film thickness of the cycloid pinwheel;

[0078] In this embodiment, the empirical formula is determined by the following formula:

[0079]

[0080] in, Indicates the oil film thickness, represents the equivalent radius of curvature, represents the dimensionless material parameters, Represents load per unit length.

[0081] Step S4: Build based on The rough surface model of the cycloidal pinwheel based on the function is used to extract the rough surface features of the cycloidal pinwheel, and the rough surface features are input into the non-Newtonian thermal elastic hydrodynamic lubrication model of the cycloidal pinwheel rough surface to obtain the oil film thickness and viscosity of the cycloidal pinwheel;

[0082] In this embodiment, surface features with roughnesses of 0.01, 0.2, 0.4 and 0.8 respectively are analyzed and obtained.

[0083] Step S5: using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloidal pinwheel to obtain a new oil film pressure value;

[0084] In this embodiment, the oil film pressure value is solved using the non-Newtonian thermal elastohydrodynamic lubrication model equations of the rough surface of the cycloid pinwheel.

[0085] Step S6: using the first convergence condition to determine whether the new oil film pressure value converges, if so, taking the new pressure value as the final pressure value, otherwise returning to step S3 to iterate until convergence, and taking the converged oil film pressure value as the final oil film pressure value;

[0086] In this embodiment, the first convergence condition is that the difference between the new oil film pressure value and the oil film pressure value of the previous iteration is within The iteration uses the multigrid method and V cycle; the oil film pressure value is divided into 5 layers in the vertical direction, and the number of grid nodes in each layer is different and increases with the increase of the number of layers. The number of grid nodes in each layer is: 9 in the first layer, 17 in the second layer, 33 in the third layer, 65 in the fourth layer, and 129 in the fifth layer. The oil film pressure value is iterated in the first layer Iterate at least once in the remaining layers, and the oil film pressure value is used in the oil film high pressure area. The dipole iteration method is used in the low pressure area of ​​the oil film. Iteration method, Bipole Iteration Method and The iteration method uses the same iteration coefficient, Bipole Iteration Method and The iteration coefficient used in the iteration method is Any value in .

[0087] Step S7: using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloid pinwheel to obtain a new oil film temperature;

[0088] In this embodiment, the non-Newtonian thermoelastic-hydrodynamic lubrication model equations of the rough surface of the cycloid pinwheel are used to solve the new oil film temperature.

[0089] Step S8: using the second convergence condition to determine whether the new oil film temperature converges, if so, taking the new oil film temperature as the final temperature, otherwise returning to step S3 to iterate until convergence, and taking the converged oil film temperature as the final oil film temperature;

[0090] In this embodiment, the second convergence condition is that the difference between the new oil film temperature and the oil film temperature of the previous iteration is within between.

[0091] Step S9: Analyze the influence of meshing point data of different rough surfaces and different cycloidal gear tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel in combination with the final oil film pressure value, the final oil film temperature and the oil film thickness; analyze the oil film characteristics of the meshing point in combination with the final oil film pressure value and the oil film thickness, and obtain the poor lubrication area, modification method and modification amount of the cycloidal pinwheel during the meshing transmission process.

[0092] In this embodiment, if Figure 3-9 As shown in the figure, it can be obtained that: the oil film thickness of the meshing point close to the tooth valley is larger, and the oil film stability is poor; the closer the meshing point is to the tooth waist, the smaller the oil film thickness is. In the process from the tooth valley to the tooth waist, the secondary pressure peak of the oil film moves to the right. The oil film stability in the central area of ​​the meshing point is good, but it is easy to break at the neck. The area near the maximum meshing force of the cycloidal pinwheel is a poor lubrication area. Add surface features of different roughness generated by the MB function, re-solve the lubrication model equation group, and compare and analyze the oil film thickness, oil film pressure and temperature change curves of each meshing point with different roughness. It can be obtained that the roughness will affect the lubrication state of the cycloidal pinwheel when it is meshing. The greater the roughness, the greater the amplitude of the oil film thickness and pressure fluctuations, and the more drastic the temperature field changes. The influence of roughness on the central area of ​​the meshing point is more obvious. The meshing point 4 and the roughness equal to 0.01 are taken as the research objects, the meshing point data when different tooth profiles are modified are replaced, and the lubrication model equations are re-solved. By comparing and analyzing the oil film thickness, oil film pressure and temperature change curves at different roughness of each meshing point, it can be obtained that after the cycloid wheel is modified, the oil film thickness and pressure will decrease, and the pressure and temperature field changes will increase. After the modification, the secondary pressure peak moves to the right, and the oil film is more stable in the center area of ​​the meshing point. But it is also more likely to break at the neck. Compared with other modification methods, when the tooth profile is modified by "negative displacement + positive equidistance" or "positive displacement + negative equidistance", the stability of the center area of ​​the meshing point is better, and the oil film has a better cooling effect on the meshing surface.

[0093] Embodiment 3

[0094] like Figure 2 As shown, a thermal elastohydrodynamic lubrication characteristic analysis system of a cycloidal pinwheel of an RV reducer according to an embodiment of the present invention comprises:

[0095] A first acquisition module: used to acquire first data of the RV reducer, wherein the first data includes meshing point data, tooth profile modification parameters, roughness and grease parameters of the cycloid pinwheel;

[0096] Model building module: used to build a non-Newtonian thermal elastic-hydrodynamic lubrication model for the rough surface of a cycloidal pinwheel;

[0097] Assigning initial value module: used to assign initial values ​​to the pressure value and viscosity of the oil film respectively using the first data, taking the mean value of the temperature field as the initial temperature value, and assigning an initial value to the oil film thickness of the cycloid pinwheel using an empirical formula;

[0098] The second acquisition module is used to build The rough surface model of the cycloidal pinwheel based on the function is used to extract the rough surface features of the cycloidal pinwheel, and the rough surface features are input into the non-Newtonian thermal elastic hydrodynamic lubrication model of the cycloidal pinwheel rough surface to obtain the oil film thickness and viscosity of the cycloidal pinwheel;

[0099] The third acquisition module is used to obtain a new oil film pressure value using a non-Newtonian thermal elastohydrodynamic lubrication model for a rough surface of a cycloidal pinwheel;

[0100] A first judgment module: used to judge whether the new oil film pressure value converges using the first convergence condition, and if so, taking the new pressure value as the final pressure value; otherwise, returning to step S3 to iterate until convergence, and taking the converged oil film pressure value as the final oil film pressure value;

[0101] The fourth acquisition module is used to obtain a new oil film temperature using a non-Newtonian thermal elastohydrodynamic lubrication model for a rough surface of a cycloidal pinwheel;

[0102] The second judgment module is used to judge whether the new oil film temperature converges by using the second convergence condition. If converged, the new oil film temperature is used as the final temperature. Otherwise, the process returns to step S3 to iterate until converged, and the converged oil film temperature is used as the final oil film temperature.

[0103] Analysis module: used to analyze the influence of meshing point data of different rough surfaces and different cycloidal gear tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel in combination with the final oil film pressure value, the final oil film temperature and the oil film thickness, and to analyze the oil film characteristics of the meshing point in combination with the final oil film pressure value and the oil film thickness, so as to obtain the poor lubrication area, modification method and modification amount of the cycloidal pinwheel in the meshing transmission process.

[0104] In this embodiment, a non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of a cycloidal pinwheel and a rough surface model of a cycloidal pinwheel are constructed, and the oil film pressure value and temperature are obtained by using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloidal pinwheel, and the oil film thickness is obtained by using the rough surface model of the cycloidal pinwheel. The influence of the meshing point data of different rough surfaces and different cycloidal wheel tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel is analyzed in combination with the oil film pressure value, oil film temperature and oil film thickness. The oil film characteristics of the meshing point are analyzed in combination with the final oil film pressure value and oil film thickness, and the lubrication poor area, modification method and modification amount of the cycloidal pinwheel in the meshing transmission process are obtained, thereby improving the transmission efficiency and transmission accuracy of the cycloidal pinwheel and reducing wear at the same time.

[0105] In summary, the embodiment of the present invention provides a method and system for analyzing the thermal elastohydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer, which constructs a non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloidal pinwheel and a rough surface model of the cycloidal pinwheel, uses the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloidal pinwheel to obtain the oil film pressure value and temperature, uses the rough surface model of the cycloidal pinwheel to obtain the oil film thickness, and combines the oil film pressure value, oil film temperature and oil film thickness to analyze the influence of the meshing point data of different rough surfaces and different cycloidal wheel tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel, combines the final oil film pressure value and oil film thickness to analyze the oil film characteristics of the meshing point, and obtains the lubrication poor area, modification method and modification amount of the cycloidal pinwheel in the meshing transmission process, thereby improving the transmission efficiency and transmission accuracy of the cycloidal pinwheel and reducing wear at the same time.

[0106] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present invention. These improvements and substitutions should also be regarded as the scope of protection of the present invention.

Claims

1. A method for analyzing the thermal elastic-hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer, characterized in that: include: Step S1: acquiring first data of the RV reducer, wherein the first data includes meshing point data, tooth profile modification parameters, roughness and grease parameters of the cycloid pinwheel; Step S2: constructing a non-Newtonian thermal elastohydrodynamic lubrication model for the rough surface of the cycloid pinwheel; Step S3: using the first data to assign initial values ​​to the pressure value and the viscosity of the oil film respectively, taking the average value of the temperature field as the initial temperature value, and using an empirical formula to assign an initial value to the oil film thickness of the cycloid pinwheel; Step S4: Build based on A cycloidal pinwheel rough surface model of the function, using the cycloidal pinwheel rough surface model to extract the rough surface features of the cycloidal pinwheel, inputting the rough surface features into the cycloidal pinwheel rough surface non-Newtonian thermal elastic hydrodynamic lubrication model, and obtaining the oil film thickness and viscosity of the cycloidal pinwheel; Step S5: using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloid pinwheel to obtain a new oil film pressure value; Step S6: using the first convergence condition to determine whether the new oil film pressure value converges, if so, taking the new pressure value as the final pressure value, otherwise returning to step S3 to iterate until convergence, and taking the converged oil film pressure value as the final oil film pressure value; Step S7: using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloid pinwheel to obtain a new oil film temperature; Step S8: using the second convergence condition to determine whether the new oil film temperature converges, if so, taking the new oil film temperature as the final temperature, otherwise returning to step S3 to iterate until convergence, and taking the converged oil film temperature as the final oil film temperature; Step S9: Analyze the influence of meshing point data of different rough surfaces and different cycloidal gear tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel in combination with the final oil film pressure value, the final oil film temperature and the oil film thickness; analyze the oil film characteristics of the meshing point in combination with the final oil film pressure value and the oil film thickness, and obtain the poor lubrication area, modification method and modification amount of the cycloidal pinwheel during the meshing transmission process.

2. According to claim 1, a method for analyzing the thermal elastic hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer, It is characterized in that The non-Newtonian thermoelastic lubrication model of the rough surface of the cycloid pinwheel in step S2 is based on the Ostwald rheological model, the energy field equation, the meshing points at different positions of the cycloid pinwheel, the cycloid wheel shaping amount and shaping method.

3. According to claim 1, a method for analyzing the thermal elastic hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer, It is characterized in that The non-Newtonian thermal elastic hydrodynamic lubrication model of the rough surface of the cycloid pinwheel in step S2 is determined by the following formula: in, represents the dimensionless pressure, Indicates the oil film thickness, Indicates viscosity, represents density, Indicates the suction speed, Indicates temperature, represents the Hertzian contact half-width, represents the maximum Hertzian contact force, express The value of the previous node in the flow direction, represents the coefficient of the Reynolds equation, represents the elastic deformation stiffness coefficient, represents the number of grid layers, Indicates the node number, The value range is , Indicates the number of oil film nodes at the meshing point, represents the characteristic scale, represents the fractal dimension, Represents the frequency index.

4. According to claim 3, a method for analyzing the thermal elastic hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer, It is characterized in that The empirical formula in step S3 is determined by the following formula: in, Indicates the oil film thickness, represents the equivalent radius of curvature, represents the dimensionless material parameters, Represents load per unit length.

5. According to claim 3, a method for analyzing the thermal elastic hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer, It is characterized in that In step S6, the first convergence condition is that the difference between the new oil film pressure value and the oil film pressure value of the previous iteration is within between.

6. A method for analyzing the thermal elastic-hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to claim 5, It is characterized in that The iteration in step S6 uses a multi-grid method and a V cycle; the oil film pressure value is divided into five layers in the vertical direction, and the number of grid nodes in each layer is different and increases with the increase of the number of layers; The oil film pressure value is iterated in the first layer The oil film pressure value is adopted in the oil film high pressure area. The dipole iteration method is used in the low pressure area of ​​the oil film. Iteration method, The bipolar iteration method and the The iteration method uses the same iteration coefficient.

7. A method for analyzing the thermal elastic-hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to claim 6, It is characterized in that The number of grid nodes in each layer is: 9 in the first layer, 17 in the second layer, 33 in the third layer, 65 in the fourth layer, and 129 in the fifth layer.

8. A method for analyzing the thermal elastic hydrodynamic lubrication characteristics of a cycloidal pinwheel of an RV reducer according to claim 6, It is characterized in that Said The bipolar iteration method and the The iteration coefficient used in the iteration method is Any value in .

9. The method for analyzing the thermal elastic hydrodynamic lubrication characteristics of the cycloid pinwheel of an RV reducer according to claim 6, It is characterized in that The second convergence condition described in step S8 is that the difference between the new oil film temperature and the oil film temperature of the previous iteration is within between.

10. A cycloidal pinwheel thermal elastohydrodynamic lubrication characteristics analysis system for RV reducer, characterized in that: include: A first acquisition module: used to acquire first data of the RV reducer, wherein the first data includes meshing point data, tooth profile modification parameters, roughness and grease parameters of the cycloid pinwheel; Model building module: used to build a non-Newtonian thermal elastic-hydrodynamic lubrication model for the rough surface of a cycloidal pinwheel; An initial value assignment module is used to assign initial values ​​to the pressure value and the viscosity of the oil film respectively using the first data, take the average value of the temperature field as the initial temperature value, and assign an initial value to the oil film thickness of the cycloid pinwheel using an empirical formula; The second acquisition module is used to build A cycloidal pinwheel rough surface model of the function, using the cycloidal pinwheel rough surface model to extract the rough surface features of the cycloidal pinwheel, inputting the rough surface features into the cycloidal pinwheel rough surface non-Newtonian thermal elastic hydrodynamic lubrication model, and obtaining the oil film thickness and viscosity of the cycloidal pinwheel; The third acquisition module is used to obtain a new oil film pressure value using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloid pinwheel; A first judgment module: used to judge whether the new oil film pressure value converges using the first convergence condition, and if so, taking the new pressure value as the final pressure value; otherwise, returning to step S3 to iterate until convergence, and taking the converged oil film pressure value as the final oil film pressure value; A fourth acquisition module: used for acquiring a new oil film temperature by using the non-Newtonian thermal elastohydrodynamic lubrication model of the rough surface of the cycloidal pinwheel; The second judgment module is used to judge whether the new oil film temperature converges by using the second convergence condition. If converged, the new oil film temperature is used as the final temperature. Otherwise, the process returns to step S3 to iterate until converged, and the converged oil film temperature is used as the final oil film temperature. Analysis module: used to analyze the influence of meshing point data of different rough surfaces and different cycloidal gear tooth profile modifications on the lubrication characteristics of the cycloidal pinwheel in combination with the final oil film pressure value, the final oil film temperature and the oil film thickness, and to analyze the oil film characteristics of the meshing point in combination with the final oil film pressure value and the oil film thickness, so as to obtain the poor lubrication area, modification method and modification amount of the cycloidal pinwheel in the meshing transmission process.

Images