Planetary roller screw radiation noise calculation method

Abstract

The invention discloses a planetary roller screw radiation noise calculation method, and belongs to the technical field of mechanical design. The method comprises the following steps: constructing a finite element model of the planetary roller screw according to structural parameters of the planetary roller screw, and analyzing through software to obtain a modal of the planetary roller screw; establishing a planetary roller screw acoustic boundary element model based on the planetary roller screw mode; importing the planetary roller screw acoustic boundary element model into an acoustic analysis module to establish a planetary roller screw sound field, and solving an acoustic transfer vector ATV through the acoustic analysis module; importing the mode of the planetary roller screw into a noise vibration module, and solving a participation factor of the mode of the planetary roller screw; and solving the radiation noise of the planetary roller screw by combining the acoustic transmission vector and the modal participation factor of the planetary roller screw. The method solves the problem that the noise of the planetary roller screw cannot be calculated in the existing research.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical design, and in particular relates to a method for calculating radiation noise of a planetary roller screw. Background Art

[0002] Planetary roller screw is a mechanical device that can convert rotational motion and linear motion into each other. With the development trend of full electrification of high-end mechanical equipment and the demand for large thrust, high precision and long life transmission mechanism in aviation, aerospace, navigation, weapons, robots, new energy equipment, etc., planetary roller screw has become a research hotspot at home and abroad as a transmission mechanism in recent years. The advantages of planetary roller screw are obvious, but the domestic production level needs to be improved. One of the main reasons is that the noise of planetary roller screw cannot be calculated, which makes it impossible to judge the health status when it makes a loud noise during operation. The calculation method of radiated noise of planetary roller screw not only provides a reference for judging its health status, but also lays the foundation for its vibration reduction and noise reduction research.

[0003] Since the research on planetary roller screws at home and abroad started later than that on transmission mechanisms such as ball screws and bearings, there are few research results on the calculation methods of planetary roller screw noise, while there are some results in the research on ball screw noise. For example, the currently disclosed planetary roller screw comprehensive performance dynamic test system can measure the positioning accuracy, noise, temperature rise, maximum speed, acceleration, etc. of the planetary roller screw; the noise generated by general bearings is divided into noise generated by the structure, noise generated by processing errors and noise caused by human operating errors, and the causes of noise, methods of suppression and possible frequencies of noise are explained; based on harmonic theory and noise experiments, a harmonic distribution model of the rolling bearing surface is established, the general influence of harmonic parameters on the noise sound pressure level is studied, and the optimal harmonic control equation is derived; based on the transient dynamic analysis model of the ball screw pair, an acoustic finite element model is established in Virtual.Lab, and the acoustic finite element method is used to analyze the sound pressure value of the external sound field of the ball screw pair, and experimental verification is carried out; Matlab is used to analyze the screw vibration and noise signal data collected by Labview, and the noise signal is studied based on the method combining wavelet packets and EMD to determine the main sound source of the ball screw.

[0004] In summary, there is currently no method for calculating the radiated noise of a planetary roller screw. Summary of the invention

[0005] Technical issues to be solved:

[0006] In order to avoid the shortcomings of the prior art, the present invention provides a method for calculating the radiated noise of a planetary roller screw. First, a three-dimensional model of a planetary roller screw is established in a modeling software, and the modal of the planetary roller screw is solved in a simulation integration platform; then, a boundary element model of a planetary roller screw is established based on the modal of the planetary roller screw; the acoustic transfer vector (ATV) and modal participation factor of the planetary roller screw are calculated using an acoustic module and a modal superposition method; finally, the radiated noise of the planetary roller screw is calculated according to the MATV method. The present invention fills the gap in the calculation of the noise of the planetary roller screw, lays a foundation for the vibration reduction and noise reduction of the planetary roller screw, and solves the problem that the existing research cannot calculate the noise of the planetary roller screw.

[0007] The technical solution of the present invention is: a method for calculating the radiated noise of a planetary roller screw, the specific steps are as follows:

[0008] The finite element model of the planetary roller screw is constructed according to the structural parameters of the planetary roller screw, and the modal of the planetary roller screw is obtained through software analysis;

[0009] Establishing an acoustic boundary element model of a planetary roller screw based on the planetary roller screw mode;

[0010] Importing the planetary roller screw acoustic boundary element model into an acoustic analysis module to establish a planetary roller screw acoustic field, and solving the acoustic transfer vector ATV through the acoustic analysis module;

[0011] Import the planetary roller screw mode into the noise and vibration module to solve the planetary roller screw mode participation factor;

[0012] The acoustic transfer vector and modal participation factor of the planetary roller screw are combined to solve the radiated noise of the planetary roller screw.

[0013] A further technical solution of the present invention is: a method for constructing a finite element model of the planetary roller screw;

[0014] Assemble all parts of the planetary roller screw in the modeling software to obtain a finite element model of the planetary roller screw;

[0015] Assign model material according to the actual material of the planetary roller screw;

[0016] Add contacts between parts; part contacts include the contact between roller and screw, roller and nut, roller and cage, roller and inner gear ring, and the contact type is Bonded;

[0017] Mesh the finite element model of the planetary roller screw; the finite element mesh size is 1 mm, and the mesh type is Tetrahedron tetrahedron mesh;

[0018] Solve for the modes of a planetary roller screw.

[0019] A further technical solution of the present invention is: the method for establishing the acoustic boundary element model of the planetary roller screw is:

[0020] Importing the planetary roller screw mode into an acoustic simulation analysis platform to extract the surface unit of the planetary roller screw;

[0021] Delete surface non-acoustic elements and superelements;

[0022] Perform acoustic boundary element meshing, and the mesh size calculation formula is as follows:

[0023]

[0024] Where c is the speed of sound, L is the grid size, and f is the frequency;

[0025] Establish the acoustic boundary element model of planetary roller screw.

[0026] A further technical solution of the present invention is: the method for establishing the acoustic field of the planetary roller screw is:

[0027] Define and apply a fluid material to the planetary roller screw acoustic boundary element model;

[0028] Convert the planetary roller screw boundary element model mesh to an acoustic mesh;

[0029] Define the sound field point network;

[0030] Insert analysis frequency, and set the sound field analysis frequency to 1-4500Hz;

[0031] Solve for the acoustic transfer vector ATV.

[0032] A further technical solution of the present invention is: the method for solving the modal participation factor of the planetary roller screw is:

[0033] Set the planetary roller screw damping ratio;

[0034] The dynamic loads of the thread pair and gear pair are solved according to the dynamic equations of the planetary roller screw and applied to the model;

[0035] Solve for the modal participation factors of a planetary roller screw.

[0036] A further technical solution of the present invention is that the damping factor of the planetary roller screw is 0.5%-2%.

[0037] A further technical solution of the present invention is: the calculation method of the dynamic load of the thread pair and the gear pair is:

[0038] The dynamic equations of the various parts of the planetary roller screw are established, where the motion differential equation of the screw is shown in formula (2):

[0039]

[0040] Where i is the number of the roller; m s is the equivalent mass of the screw; ω c is the angular velocity of the cage; x s is the axial displacement of the screw; y s is the radial displacement of the screw; α s The angle between the normal force at the contact point between the screw and the roller and the plane formed by the axial and radial directions of the screw; is the phase angle between the screw and the i-th roller; I s is the equivalent moment of inertia of the screw rotating around its axis; r s T is the middle diameter of the screw; in is the screw drive torque; k s and c s Indicates the lateral support stiffness and damping of the screw; k st and c st k is the screw thread stiffness and damping; sRi 、c sRi Represents the meshing stiffness and meshing damping of the thread pair on the screw side; r sp is the contact radius of the screw; u s is the torsional displacement of the screw; δ sRi is the relative displacement between the contact side of the screw and the roller, and the calculation formula is shown in formula (3):

[0041]

[0042] Where:

[0043]

[0044] In the formula, e sRi (t) is the error between the ith roller and the screw; is the phase angle of the i-th roller; γs is the angle between the projection of the screw normal contact force on the plane formed by the axial and radial directions of the screw and the axial direction of the screw; r Rp is the contact radius of the roller, n is the number of screw heads, P is the screw thread lead; N is the number of rollers;

[0045] The differential equation of the inner gear ring motion is established as shown in formula (6):

[0046]

[0047] Where i is the number of the roller; m r is the mass of the inner gear ring, x r is the axial displacement of the inner gear ring; y r is the radial displacement of the inner gear ring; ω cI is the angular velocity of the cage; r is the moment of inertia of the inner gear ring; r r is the base circle radius of the inner gear ring; is the phase angle between the inner gear ring and the i-th roller; k r and c r represents the lateral support stiffness and damping of the inner gear ring; k rt and c rt is the stiffness and damping of the inner ring gear; k rRi 、c rRi Indicates the meshing stiffness and meshing damping of the gear pair; u r is the torsional displacement of the inner gear ring; δ rRi is the relative displacement between the roller and the inner gear ring along the meshing line, and the calculation formula is shown in formula (7):

[0048]

[0049] In the formula,

[0050]

[0051] In the formula, u Ri is the torsional displacement of the ith roller; e rRi (t) is the error between the ith roller and the inner gear ring; is the phase angle of the i-th roller; α r The angle between the normal force at the contact point between the inner gear ring and the roller and the plane formed by the axial and radial directions of the inner gear ring;

[0052] The motion differential equation of the nut is established as shown in formula (9):

[0053]

[0054] Where i is the number of the roller; m n is the equivalent mass of the nut; x n is the axial displacement of the nut; y n is the radial displacement of the nut; ω c is the angular velocity of the cage; is the phase angle between the nut and the i-th roller; α n k is the angle between the normal force at the contact point between the nut and the roller and the plane formed by the axial and radial directions of the nut; n and c n Indicates the lateral support stiffness and damping of the nut; k nt and c nt is the nut thread stiffness and damping; k nRi 、c nRi Indicates the thread engagement stiffness and engagement damping on the nut side; I n is the equivalent moment of inertia of the nut rotating around the axis; rn is the median diameter of the nut; u n is the torsional displacement of the nut; δ nRi is the relative displacement of the contact side of the roller nut, and the calculation formula is shown in formula (10):

[0055]

[0056] In the formula,

[0057]

[0058] Where n is the number of nut heads; r n and r R are the contact radius of the nut and the roller respectively; u Ri is the torsional displacement of the ith roller; P is the nut thread lead; e nRi (t) is the error between the ith roller and the nut; is the phase angle of the i-th roller; γ n is the angle between the projection of the nut normal contact force on the plane formed by the nut's axial and radial directions and the nut's axial direction; N is the number of rollers;

[0059] The motion differential equation of the roller is established as shown in equation (13):

[0060]

[0061] Where i is the serial number of the roller; Ri is the equivalent moment of inertia of the ith roller rotating around the axis; u Ri is the torsional displacement of the ith roller; k sR and c sR Indicates the contact stiffness and damping between the roller and the screw; k Rt and c Rt Represents the roller thread stiffness and damping; α s The angle between the normal force at the contact point between the screw and the roller and the plane formed by the axial and radial directions of the screw; α n The angle between the normal force at the contact point between the nut and the roller and the plane formed by the axial and radial directions of the nut; δ sRi is the relative displacement between the screw and the roller contact side; δ nRi is the relative displacement of the roller nut contact side; r R is the roller radius.

[0062] The motion differential equation of the cage is established as shown in equation (14):

[0063]

[0064] In the formula, I c is the equivalent moment of inertia of the cage rotating around the axis; uc is the torsional displacement of the cage; k ct and c ct is the stiffness and damping of the cage matrix; r c is the cage radius;

[0065] The formula for calculating the dynamic meshing force between the planetary roller screw thread pair and the gear pair is shown in formula (15):

[0066]

[0067] In the formula, F sRi F is the dynamic load of roller and screw; rRi is the dynamic load of rollers and internal gear ring, F nRi is the dynamic load on the roller and nut.

[0068] The dynamic equations of the planetary roller screw are solved by combining equations (2)-(14) and substituted into equation (15) to obtain the time domain dynamic loads of the thread pair and the gear pair. The time domain dynamic loads are converted into frequency domain dynamic loads using the FFT function and applied to the planetary roller screw.

[0069] A planetary roller screw radiation noise calculation system, including a finite element module, an acoustic simulation analysis module, an acoustic field module, a noise vibration module, and an acoustic boundary element module;

[0070] Construct the finite element model of planetary roller screw through the finite element module;

[0071] The acoustic boundary element model of the planetary roller screw is constructed through the acoustic simulation analysis module;

[0072] The acoustic field of the planetary roller screw is constructed through the acoustic field module to solve the acoustic transfer vector ATV;

[0073] The modal participation factor of the planetary roller screw is solved through the noise and vibration module;

[0074] The noise radiated by a planetary roller screw is solved using the Boundary Element Acoustics Module.

[0075] An electronic device comprises at least one processor and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the planetary roller screw radiation noise calculation method.

[0076] A computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the planetary roller screw radiation noise calculation method when executed.

[0077] Beneficial Effects

[0078] The beneficial effects of the present invention are as follows: the present invention performs modal analysis on the planetary roller screw model, applies loads on the basis of modal analysis to carry out vibration response calculation and modal contribution calculation; establishes a boundary element model through the planetary roller screw finite element model and calculates the acoustic transfer vector; finally, calculates the radiated noise of the gearbox through the acoustic transfer vector and modal contribution. The method of the present invention fills the gap in the calculation of planetary roller screw noise and lays the foundation for vibration reduction and noise reduction of planetary roller screws. The specific advantages are as follows:

[0079] 1. This invention uses LMS Virtual Lab based on the MATV method to solve the radiation noise of the planetary roller screw, filling the gap in the calculation of the noise of the planetary roller screw. At the design level, it provides noise indicators for the design of the planetary roller screw. At the application level, it provides a basis for state judgment for the planetary roller screw. At the detection level, it provides a health detection method for the planetary roller screw. At the experimental level, it provides reference value for the experimental results of the noise of the planetary roller screw.

[0080] 2. The present invention establishes a planetary roller screw dynamic model to calculate the dynamic load, which not only considers the contact dynamic load of the threaded pair between the roller and the screw and the nut, but also considers the contact dynamic load of the gear pair between the roller and the inner ring gear, thus improving the current planetary roller screw dynamic model that only considers the contact of the threaded pair, making the radiated noise results of the planetary roller screw closer to the experimental results.

[0081] 3. The present invention can calculate the radiated noise of the planetary roller screw under different loads. It can solve the maximum load of the nut within the noise requirement range, and can also solve the maximum noise within the load requirement range. It provides a variety of adaptation schemes for the planetary roller screw load-noise and meets the multi-working condition application requirements of the planetary roller screw. BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 Flow chart of a method for calculating radiated noise of a planetary roller screw in an embodiment of the present invention;

[0083] Figure 2 A three-dimensional model diagram of a planetary roller screw in an embodiment of the present invention;

[0084] Figure 3 A finite element model diagram of a planetary roller screw in an embodiment of the present invention;

[0085] Figure 4 Graph showing the calculation results of the natural frequency of the planetary roller screw in an embodiment of the present invention;

[0086] Figure 5 It is a time domain diagram of the dynamic load of the planetary roller screw in the embodiment of the present invention;

[0087] Figure 6 It is the frequency domain diagram of the roller-screw in the X, Y and Z directions in the embodiment of the present invention;

[0088] Figure 7 It is the frequency domain diagram of the roller-nut in the X, Y and Z directions in the embodiment of the present invention;

[0089] Figure 8 It is the frequency domain diagram of the roller-ring gear in the X, Y and Z directions in the embodiment of the present invention;

[0090] Fig. 9 This is a field point distribution diagram of the noise radiated by the planetary roller screw in an embodiment of the present invention;

[0091] Fig.10 The noise test results of the planetary roller screw in the embodiment of the present invention;

[0092] Explanation of reference numerals: 1. Screw, 2. Roller, 3. Internal gear ring, 4. Nut, 5. Cage. DETAILED DESCRIPTION

[0093] The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0094] Based on the problem that existing research cannot calculate the noise of planetary roller screws, the present invention provides a method for calculating the radiated noise of planetary roller screws: first, a three-dimensional model of the planetary roller screw is established in Solidworks, and the mode of the planetary roller screw is solved in Ansys Workbench. Then, the modal result file of the planetary roller screw is imported into Ansys APDL to generate a modal result cdb file, and the modal result cdb file is imported into LMS Virtual Lab to establish a boundary element model of the planetary roller screw. Then, the acoustic transfer vector (ATV) and modal participation factor of the planetary roller screw are calculated using the LMS Virtual Lab acoustic module and the modal superposition method. Finally, the radiated noise of the planetary roller screw is calculated according to the MATV method. The present invention fills the gap in the calculation of planetary roller screw noise and lays the foundation for vibration reduction and noise reduction of planetary roller screws. The specific steps are as follows:

[0095] Step 1: The structural parameters of the planetary roller screw are used to construct a finite element model of the planetary roller screw, and the modal of the planetary roller screw is obtained through software analysis;

[0096] Step 2: Establishing an acoustic boundary element model of a planetary roller screw based on the planetary roller screw mode;

[0097] Step 3: Import the planetary roller screw acoustic boundary element model into the acoustic analysis module to establish the planetary roller screw acoustic field, and solve the acoustic transfer vector ATV through the acoustic analysis module;

[0098] Step 4: Import the planetary roller screw mode into the noise and vibration module to solve the planetary roller screw mode participation factor;

[0099] Step 5: Combine the acoustic transfer vector and modal participation factor of the planetary roller screw to solve the radiated noise of the planetary roller screw.

[0100] The above technical solution is further described below in conjunction with the accompanying drawings and implementation:

[0101] This embodiment provides a method for calculating the radiated noise of a planetary roller screw, and the specific steps are as follows:

[0102] Step 1, modal analysis of planetary roller screw;

[0103] A three-dimensional model is established in Solidworks according to the structural parameters of the planetary roller screw, the generated x_t file is imported into Ansys Workbench, and the modal module is used to solve the mode.

[0104] First, all the parts of the planetary roller screw are merged into a new structure. Then, the model material is assigned according to the material of the planetary roller screw. Then, the contact between the parts is added. Then, the model is meshed, and finally, the modes of the planetary roller screw are solved.

[0105] In this embodiment, the material of the planetary roller screw is GCr15; the part contacts include the contact between the roller and the screw, the roller and the nut, the roller and the retaining cage, and the roller and the inner ring gear, and the contact type is Bonded; the finite element grid size is 1 mm, and the grid type is Tetrahedron tetrahedron grid.

[0106] Step 2, establishing the acoustic boundary element model of the planetary roller screw;

[0107] The modal result dat file of the planetary roller screw solved by Ansys Workbench is imported into Ansys APDL, converted into a cdb file, and then imported into LMS Virtual Lab to establish the boundary element model of the planetary roller screw.

[0108] Firstly, the surface elements of the planetary roller screw are extracted, then the surface non-acoustic elements and super-elements are deleted, and finally the acoustic boundary element meshing is performed to establish the acoustic boundary element model of the planetary roller screw.

[0109] In this embodiment, the acoustic boundary element grid size calculation formula is:

[0110]

[0111] Where c is the speed of sound, L is the grid size, and f is the frequency. Since the dynamic load of the planetary roller screw thread pair is small after 250Hz, and the dynamic load of the gear pair is small after 4500Hz, the grid size is set to 12mm, and the upper limit frequency of the calculation is 4500Hz.

[0112] Step 3, the planetary roller screw sound field is established;

[0113] The boundary element model of the planetary roller screw is imported into the Acoustic analysis module in LMS Virtual Lab to solve the acoustic transfer vector ATV.

[0114] First, the fluid material is defined and applied to the boundary element model. Then the planetary roller screw boundary element mesh is converted to an acoustic mesh. The acoustic field point network is defined. Finally, the analysis frequencies are inserted and the acoustic transfer vector ATV is solved.

[0115] In this embodiment, the sound field analysis frequency is set to 1-4500 Hz.

[0116] Step 4, calculation of the modal participation factor of the planetary roller screw;

[0117] The modal analysis results rst file of the planetary roller screw finite element model calculation is imported into the Noise&Virbation module in LMS Virtual Lab to solve the modal participation factor of the planetary roller screw.

[0118] Firstly, the damping ratio of the planetary roller screw is set. Then, the dynamic loads of the thread pair and the gear pair are solved according to the dynamic equation of the planetary roller screw and applied to the model. Finally, the modal participation factor of the planetary roller screw is solved.

[0119] The damping factor is generally 0.5%-2%, and is set to 2% in this embodiment.

[0120] Step 5, calculation of the radiated noise of the planetary roller screw;

[0121] The calculation results of the acoustic transfer vector and modal participation factor of the planetary roller screw are imported into LMS Virtual Lab, and the Acoustic BME acoustic boundary element module is used to solve the radiated noise of the planetary roller screw.

[0122] First, import the planetary roller screw acoustic transfer vector ATV file in step 3 into LMS Virtual Lab. Then import the planetary roller screw modal participation factor results in step 4 into LMS Virtual Lab. Then transfer the finite element data on the modal participation factor to the planetary roller screw boundary element model. Finally, use the Acoustic BME acoustic boundary element module to solve the planetary roller screw radiated noise using the MATV method.

[0123] In this embodiment, the calculation method of the dynamic load of the thread pair and the gear pair is:

[0124] The dynamic equations of the various parts of the planetary roller screw are established, where the motion differential equation of the screw is shown in formula (2):

[0125]

[0126] Where i is the number of the roller; m s is the equivalent mass of the screw; ω c is the angular velocity of the cage; x s is the axial displacement of the screw; y s is the radial displacement of the screw; α s The angle between the normal force at the contact point between the screw and the roller and the plane formed by the axial and radial directions of the screw; is the phase angle between the screw and the i-th roller; I s is the equivalent moment of inertia of the screw rotating around its axis; r s T is the middle diameter of the screw; in is the screw drive torque; k s and c s Indicates the lateral support stiffness and damping of the screw; k st and c st k is the screw thread stiffness and damping; sRi 、c sRi Represents the meshing stiffness and meshing damping of the thread pair on the screw side; r sp is the contact radius of the screw; u s is the torsional displacement of the screw; δ sRi is the relative displacement between the contact side of the screw and the roller, and the calculation formula is shown in formula (3):

[0127]

[0128] Where:

[0129]

[0130] In the formula, e sRi (t) is the error between the ith roller and the screw; is the phase angle of the i-th roller; γs r is the angle between the projection of the screw's normal contact force on the plane formed by the screw's axial and radial directions and the screw's axial direction; Rp is the contact radius of the roller, n is the number of screw heads, P is the screw thread lead; N is the number of rollers.

[0131] The differential equation of the inner gear ring motion is established as shown in equation (6):

[0132]

[0133] Where i is the number of the roller; m r is the mass of the inner gear ring, x r is the axial displacement of the inner gear ring; y r is the radial displacement of the inner gear ring; ω c I is the angular velocity of the cage; r is the moment of inertia of the inner gear ring; r r is the base circle radius of the inner gear ring; is the phase angle between the inner gear ring and the i-th roller; k r and c r represents the lateral support stiffness and damping of the inner gear ring; k rt and c rt is the stiffness and damping of the inner ring gear; k rRi 、c rRi Indicates the meshing stiffness and meshing damping of the gear pair; u r is the torsional displacement of the inner gear ring; δ rRi is the relative displacement between the roller and the inner gear ring along the meshing line, and the calculation formula is shown in formula (7):

[0134]

[0135] In the formula,

[0136]

[0137] In the formula, u Ri is the torsional displacement of the ith roller; e rRi (t) is the error between the ith roller and the inner gear ring; is the phase angle of the i-th roller; α r It is the angle between the normal force at the contact point between the inner gear ring and the roller and the plane formed by the axial and radial directions of the inner gear ring.

[0138] The motion differential equation of the nut is established as shown in equation (9):

[0139]

[0140] Where i is the number of the roller; m n is the equivalent mass of the nut; x nis the axial displacement of the nut; y n is the radial displacement of the nut; ω c is the angular velocity of the cage; is the phase angle between the nut and the i-th roller; α n k is the angle between the normal force at the contact point between the nut and the roller and the plane formed by the axial and radial directions of the nut; n and c n Indicates the lateral support stiffness and damping of the nut; k nt and c nt is the nut thread stiffness and damping; k nRi 、c nRi Indicates the thread engagement stiffness and engagement damping on the nut side; I n is the equivalent moment of inertia of the nut rotating around the axis; r n is the median diameter of the nut; u n is the torsional displacement of the nut; δ nRi is the relative displacement of the contact side of the roller nut, and the calculation formula is shown in formula (10):

[0141]

[0142] In the formula,

[0143]

[0144] Where n is the number of nut heads; r n and r R are the contact radius of the nut and the roller respectively; u Ri is the torsional displacement of the ith roller; P is the nut thread lead; e nRi (t) is the error between the ith roller and the nut; is the phase angle of the i-th roller; γ n It is the angle between the projection of the normal contact force of the nut on the plane formed by the axial and radial directions of the nut and the axial direction of the nut; N is the number of rollers.

[0145] The motion differential equation of the roller is established as shown in equation (13):

[0146]

[0147] Where i is the serial number of the roller; Ri is the equivalent moment of inertia of the ith roller rotating around the axis; u Ri is the torsional displacement of the ith roller; k sR and c sR Indicates the contact stiffness and damping between the roller and the screw; k Rt and c Rt Represents the roller thread stiffness and damping; α sThe angle between the normal force at the contact point between the screw and the roller and the plane formed by the axial and radial directions of the screw; α n The angle between the normal force at the contact point between the nut and the roller and the plane formed by the axial and radial directions of the nut; δ sRi is the relative displacement between the screw and the roller contact side; δ nRi is the relative displacement of the roller nut contact side; r R is the roller radius.

[0148] The motion differential equation of the cage is established as shown in equation (14):

[0149]

[0150] In the formula, I c is the equivalent moment of inertia of the cage rotating around the axis; u c is the torsional displacement of the cage; k ct and c ct is the stiffness and damping of the cage matrix; r c is the cage radius.

[0151] The calculation of the dynamic meshing force between the planetary roller screw thread pair and the gear pair is shown in formula (15):

[0152]

[0153] In the formula, F sRi F is the dynamic load of roller and screw; rRi is the dynamic load of rollers and internal gear ring, F nRi is the dynamic load on the roller and nut.

[0154] The planetary roller screw dynamic equation is solved by combining equations (2)-(14). The equations are substituted into equation (15) to solve the planetary roller screw dynamic equation to obtain the time domain dynamic loads of the thread pair and the gear pair. The time domain dynamic loads are imported into Matlab and converted into frequency domain dynamic loads using the FFT function and applied to the planetary roller screw.

[0155] Example:

[0156] A method for calculating the radiation noise of a planetary roller screw of the present invention is implemented on a planetary roller screw. Figure 2 As shown, the standard planetary roller screw comprises a screw 1, a roller 2, an inner gear ring 3, a nut 4, and a retaining frame 5. The parameter dimensions of the planetary roller screw are shown in Table 1.

[0157] Table 1 Planetary roller screw parameters

[0158] Lead Screw Roller Nuts Internal gear ring Middle diameter(mm) 24 8 40 / Number of heads 5 1 5 / Pitch(mm) 2 2 2 / Flank angle(°) 45 45 45 / Pressure angle (°) / / / 35 Modulus / / / 0.5

[0159] According to the parameters in Table 1, a three-dimensional model of the planetary roller screw is established. Figure 2 As shown, 1 is a lead screw, 2 is a roller, 3 is an inner gear ring, 4 is a nut, and 5 is a retaining frame.

[0160] Import the 3D model of the planetary roller screw into Ansys Workbench and build a finite element model of the planetary roller screw. Figure 3 shown.

[0161] According to the method in step 1, the calculation results of the first ten modes of the planetary roller screw are as follows: Figure 4 As shown in the figure, the first three order modes are 0, and the fourth and fifth order modes are 220Hz, which is consistent with the theoretical calculation results of the planetary roller screw modal, verifying the correctness of this model.

[0162] According to the method in step 4, the dynamic load calculation method of the planetary roller screw is solved. The dynamic load of the planetary roller screw with the parameters shown in Table 1 at a speed of 2000r / min and an axial load of 20kN is as follows: Figure 5 The time domain dynamic load is imported into Matlab and converted into the frequency domain dynamic load using the FFT function as shown in Figure 6-Figure 8 shown.

[0163] According to the planetary roller screw radiation noise calculation method of the present invention, 8 field points are set as follows Fig. 9 As shown, the results of solving the radiation noise of each field point of the planetary roller screw are shown in Table 2.

[0164] Table 2 Radiated noise results of each field point of planetary roller screw

[0165]

[0166] According to Table 2, the average value of the radiated noise of the planetary roller screw is between 90-106dB. In the design and analysis of the comprehensive performance test bench of the planetary roller screw based on thermal error compensation, Luo Wei et al. found that the noise test results of the planetary roller screw are as follows: Fig.10 As shown in the figure, the average noise value is about 90, and the calculated value of the present invention is close to the experimental value. In addition, the noise of field points 1 and 2 is relatively large, followed by field points 5 and 6, that is, the noise above the planetary roller screw and the screw mounting end is relatively large, and the subsequent noise optimization should be carried out with the screw mounting end as the object.

[0167] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A method for calculating the radiated noise of a planetary roller screw, characterized in that The specific steps are as follows: The finite element model of the planetary roller screw is constructed according to the structural parameters of the planetary roller screw, and the modal of the planetary roller screw is obtained through software analysis; Establishing an acoustic boundary element model of a planetary roller screw based on the planetary roller screw mode; Importing the planetary roller screw acoustic boundary element model into an acoustic analysis module to establish a planetary roller screw acoustic field, and solving the acoustic transfer vector ATV through the acoustic analysis module; Import the planetary roller screw mode into the noise and vibration module to solve the planetary roller screw mode participation factor; The acoustic transfer vector and modal participation factor of the planetary roller screw are combined to solve the radiated noise of the planetary roller screw.

2. The method for calculating the radiated noise of a planetary roller screw according to claim 1, characterized in that: A method for constructing a finite element model of the planetary roller screw; Assemble all parts of the planetary roller screw in the modeling software to obtain a finite element model of the planetary roller screw; Assign model material according to the actual material of the planetary roller screw; Add contacts between parts; part contacts include the contact between roller and screw, roller and nut, roller and cage, roller and inner gear ring, and the contact type is Bonded; Mesh the finite element model of the planetary roller screw; the finite element mesh size is 1 mm, and the mesh type is Tetrahedron tetrahedron mesh; Solve for the modes of a planetary roller screw.

3. The method for calculating the radiated noise of a planetary roller screw according to claim 1, characterized in that: The method for establishing the acoustic boundary element model of the planetary roller screw is: Importing the planetary roller screw mode into an acoustic simulation analysis platform to extract the surface unit of the planetary roller screw; Delete surface non-acoustic elements and superelements; Perform acoustic boundary element meshing, and the mesh size calculation formula is as follows: Where c is the speed of sound, L is the grid size, and f is the frequency; Establish the acoustic boundary element model of planetary roller screw.

4. The method for calculating the radiated noise of a planetary roller screw according to claim 1, characterized in that: The method for establishing the planetary roller screw sound field is: Define and apply a fluid material to the planetary roller screw acoustic boundary element model; Convert the planetary roller screw boundary element model mesh to an acoustic mesh; Define the sound field point network; Insert analysis frequency, and set the sound field analysis frequency to 1-4500Hz; Solve for the acoustic transfer vector ATV.

5. The method for calculating the radiated noise of a planetary roller screw according to claim 1, characterized in that: The solution method for the modal participation factor of the planetary roller screw is: Set the planetary roller screw damping ratio; The dynamic loads of the thread pair and gear pair are solved according to the dynamic equations of the planetary roller screw and applied to the model; Solve for the modal participation factors of a planetary roller screw.

6. A method for calculating the radiated noise of a planetary roller screw according to claim 5, characterized in that: The damping factor of the planetary roller screw is 0.5%-2%.

7. A method for calculating the radiated noise of a planetary roller screw according to claim 5, characterized in that: The calculation method of the dynamic load of the thread pair and the gear pair is: The dynamic equations of the various parts of the planetary roller screw are established, where the motion differential equation of the screw is shown in formula (2): Where i is the number of the roller; m s is the equivalent mass of the screw; ω c is the angular velocity of the cage; x s is the axial displacement of the screw; y s is the radial displacement of the screw; α s The angle between the normal force at the contact point between the screw and the roller and the plane formed by the axial and radial directions of the screw; is the phase angle between the screw and the i-th roller; I s is the equivalent moment of inertia of the screw rotating around its axis; r s T is the middle diameter of the screw; in is the screw drive torque; k s and c s Indicates the lateral support stiffness and damping of the screw; k st and c st k is the screw thread stiffness and damping; sRi 、c sRi Represents the meshing stiffness and meshing damping of the thread pair on the screw side; r sp is the contact radius of the screw; u s is the torsional displacement of the screw; δ sRi is the relative displacement between the contact side of the screw and the roller, and the calculation formula is shown in formula (3): Where: In the formula, e sRi (t) is the error between the ith roller and the screw; is the phase angle of the i-th roller; γ s r is the angle between the projection of the screw's normal contact force on the plane formed by the screw's axial and radial directions and the screw's axial direction; Rp is the contact radius of the roller, n is the number of screw heads, P is the screw thread lead; N is the number of rollers; The differential equation of the inner gear ring motion is established as shown in formula (6): Where i is the number of the roller; m r is the mass of the inner gear ring, x r is the axial displacement of the inner gear ring; y r is the radial displacement of the inner gear ring; ω c I is the angular velocity of the cage; r is the moment of inertia of the inner gear ring; r r is the base circle radius of the inner gear ring; is the phase angle between the inner gear ring and the i-th roller; k r and c r represents the lateral support stiffness and damping of the inner gear ring; k rt and c rt is the stiffness and damping of the inner ring gear; k rRi 、c rRi Indicates the meshing stiffness and meshing damping of the gear pair; u r is the torsional displacement of the inner gear ring; δ rRi is the relative displacement between the roller and the inner gear ring along the meshing line, and the calculation formula is shown in formula (7): In the formula, In the formula, u Ri is the torsional displacement of the ith roller; e rRi (t) is the error between the ith roller and the inner gear ring; is the phase angle of the i-th roller; α r The angle between the normal force at the contact point between the inner gear ring and the roller and the plane formed by the axial and radial directions of the inner gear ring; The motion differential equation of the nut is established as shown in formula (9): Where i is the number of the roller; m n is the equivalent mass of the nut; x n is the axial displacement of the nut; y n is the radial displacement of the nut; ω c is the angular velocity of the cage; is the phase angle between the nut and the i-th roller; α n k is the angle between the normal force at the contact point between the nut and the roller and the plane formed by the axial and radial directions of the nut; n and c n Indicates the lateral support stiffness and damping of the nut; k nt and c nt is the nut thread stiffness and damping; k nRi 、c nRi Indicates the thread engagement stiffness and engagement damping on the nut side; I n is the equivalent moment of inertia of the nut rotating around the axis; r n is the median diameter of the nut; u n is the torsional displacement of the nut; δ nRi is the relative displacement of the contact side of the roller nut, and the calculation formula is shown in formula (10): In the formula, Where n is the number of nut heads; r n and r R are the contact radius of the nut and the roller respectively; u Ri is the torsional displacement of the ith roller; P is the nut thread lead; e nRi (t) is the error between the ith roller and the nut; is the phase angle of the i-th roller; γ n is the angle between the projection of the nut normal contact force on the plane formed by the nut's axial and radial directions and the nut's axial direction; N is the number of rollers; The motion differential equation of the roller is established as shown in equation (13): Where i is the serial number of the roller; Ri is the equivalent moment of inertia of the ith roller rotating around the axis; u Ri is the torsional displacement of the ith roller; k sR and c sR Indicates the contact stiffness and damping between the roller and the screw; k Rt and c Rt Represents the roller thread stiffness and damping; α s The angle between the normal force at the contact point between the screw and the roller and the plane formed by the axial and radial directions of the screw; α n The angle between the normal force at the contact point between the nut and the roller and the plane formed by the axial and radial directions of the nut; δ sRi is the relative displacement between the screw and the roller contact side; δ nRi is the relative displacement of the roller nut contact side; r R is the roller radius; The motion differential equation of the cage is established as shown in equation (14): In the formula, I c is the equivalent moment of inertia of the cage rotating around the axis; u c is the torsional displacement of the cage; k ct and c ct is the stiffness and damping of the cage matrix; r c is the cage radius; The formula for calculating the dynamic meshing force between the planetary roller screw thread pair and the gear pair is shown in formula (15): In the formula, F sRi F is the dynamic load of roller and screw; rRi is the dynamic load of rollers and internal gear ring, F nRi is the dynamic load of the roller and nut; The dynamic equations of the planetary roller screw are solved by combining equations (2)-(14) and substituted into equation (15) to obtain the time domain dynamic loads of the thread pair and the gear pair. The time domain dynamic loads are converted into frequency domain dynamic loads using the FFT function and applied to the planetary roller screw.

8. A planetary roller screw radiation noise calculation system, used to implement the planetary roller screw radiation noise calculation method according to any one of claims 1 to 7; characterized in that: Including finite element module, acoustic simulation analysis module, sound field module, noise vibration module, acoustic boundary element module; Construct the finite element model of planetary roller screw through the finite element module; The acoustic boundary element model of the planetary roller screw is constructed through the acoustic simulation analysis module; The acoustic field of the planetary roller screw is constructed through the acoustic field module to solve the acoustic transfer vector ATV; The modal participation factor of the planetary roller screw is solved through the noise and vibration module; The noise radiated by a planetary roller screw is solved using the Boundary Element Acoustics Module.

9. An electronic device, characterized in that: It includes at least one processor and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the planetary roller screw radiation noise calculation method as described in any one of claims 1-7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the planetary roller screw radiation noise calculation method as described in any one of claims 1-7 when executed.

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