Method for evaluating random vibration strength of shielding plate and copper bar of gearbox motor controller

Abstract

The invention discloses a gearbox motor controller shielding plate and copper bar random vibration strength evaluation method. The method comprises the steps that an overall geometric model of a gearbox motor controller is established; performing grid division on each component in the controller and setting material attributes; fixing constraint is applied to bolt connecting holes for mounting the supporting legs and the whole vehicle; calculating and extracting modal information of the controller in a set vibration frequency range; respectively applying the power spectrum densities in the X, Y and Z directions to judge whether the strength of the shielding plate and the copper bar meets the requirements or not within a certain probability range; respectively calculating unit harmonic responses in the X, Y and Z directions, and applying a load to judge whether the fatigue of the shielding plate and the copper bar meets the requirements or not. According to the method for evaluating the random vibration strength of the shielding plate and the copper bar of the gearbox motor controller, the dead weight of the bolts is considered, welding of the pins and the plate is simplified, and the strength and fatigue calculation of the shielding plate and the copper bar is more accurate through a more simplified and accurate modeling mode.

Description

Technical Field

[0001] The invention belongs to the technical field of gearboxes, and in particular to a method for evaluating the random vibration intensity of a shielding plate and a copper busbar of a gearbox motor controller. Background Art

[0002] As the core power electronic unit of electric vehicles, the gearbox motor controller will not only generate self-vibration during driving, but also be subjected to excitation vibration caused by uneven road surfaces, which will cause fatigue damage to the motor controller due to the cumulative effect of vibration. To ensure the safety and reliability of the controller structure and avoid the occurrence of random vibration failure of the controller due to insufficient strength of components such as copper bars and shielding sheets, this is a technical problem that needs to be solved urgently.

[0003] However, there are a large number of internal components and bolts in the controller. The existing evaluation method is not simple and accurate enough, and ignores the dead weight of the bolts, which makes the calculation efficiency low and the results inaccurate.

[0004] It is desirable to provide an improved random vibration strength evaluation method for a gearbox motor controller shield plate and copper busbars, particularly with respect to improving the accuracy of the evaluation results. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a random vibration intensity evaluation method for a shielding plate and a copper busbar of a gearbox motor controller, the purpose of which is to improve the accuracy of the evaluation result.

[0006] In order to achieve the above purpose, the technical solution adopted by the present invention is: a random vibration intensity evaluation method for a gearbox motor controller shielding plate and a copper busbar, comprising:

[0007] Establishing a geometric model of the gearbox motor controller as a whole; the controller as a whole comprises a copper bus, a support leg and a thin plate member, and the thin plate member comprises a shielding plate;

[0008] Mesh each component in the controller and set material properties;

[0009] Apply fixed constraints at the bolt connection holes where the support legs are installed with the vehicle;

[0010] Calculate and extract the modal information of the controller within the set vibration frequency range;

[0011] Apply the power spectrum density in the X, Y and Z directions respectively to determine whether the strength of the shielding plate and the copper bar meets the requirements within a certain probability range;

[0012] The unit harmonic response in the X, Y and Z directions is calculated respectively, and loads are applied to determine whether the fatigue of the shielding plate and the copper bar meets the requirements.

[0013] The specific method of meshing each component in the controller as a whole and setting material properties is as follows:

[0014] The support legs are divided into solid grids of more than 3 layers;

[0015] The thin plate adopts high-order shell elements to perform mesh division and set material properties;

[0016] Using common nodes to perform meshing and set material properties inside each component of the controller as a whole;

[0017] The pin welding positions all use common nodes for meshing and setting material properties.

[0018] The controller as a whole includes a film capacitor, a circuit board and a connector. The film capacitor, the circuit board and the connector are defined as a mass unit according to the center position, and the inertia moment of each component is given to the X / Y / Z axis.

[0019] The components of the controller as a whole include a drive board component, a control board component, an IGBT component, a relay component, a fuse component and a DC EMC filter component.

[0020] The bolt adopts bar unit, and the cross section of the bar unit is defined by the nominal diameter of the bolt. The bolt and the surrounding parts are connected by rb2 unit.

[0021] The bar unit is divided into two sections. The bar unit at the bolt head is consistent with the axial length of the component through hole, and the bar unit at the thread of the bolt is consistent with the thread length position. The two sections of the bar unit are connected by a common node.

[0022] The rb2 unit captures the mesh within 1.5 times the washer outside the bolt hole on the upper and lower surfaces of each component at the bolt position, and captures the mesh within 1.5 times the washer outside the bolt hole on the top surface of each component and at the thread position at the thread. The rb2 unit and the bar unit are connected using common nodes.

[0023] Before the calculation and extraction of the modal information of the controller within the set vibration frequency range, the method further includes:

[0024] The upper limit of the random vibration frequency range is set to be no less than the upper limit of the random vibration test condition frequency range, and the lower limit is set to be twice the lower limit of the random vibration test condition frequency range.

[0025] The specific method of applying load to calculate whether the random vibration fatigue strength of the gearbox motor controller shielding plate and the copper bar meets the requirements is:

[0026] Define damping;

[0027] At the bolt connection holes where the support legs and the vehicle are installed, unit accelerations in the X, Y and Z directions are applied to calculate the unit harmonic response.

[0028] After the calculation is completed, the power spectrum density is applied to obtain the stress spectrum of the shielding plate and the copper busbar;

[0029] The SN curve is introduced to calculate the fatigue damage of the shielding plate and the copper busbar;

[0030] The calculated fatigue damage of the shielding plate and the copper busbar is compared with the design allowable value parameters of the shielding plate and the copper busbar to confirm whether the shielding plate and the copper busbar meet the requirements.

[0031] The random vibration strength evaluation method of the transmission motor controller shielding plate and copper busbar of the present invention takes into account the deadweight of the bolts, simplifies the welding of the pins and the plates, and establishes the overall geometric model of the transmission motor controller through a more simplified and accurate modeling method, so that the strength and fatigue calculation of the shielding plate and the copper busbar is more accurate, the calculation efficiency is high, and the accuracy of the evaluation results can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] This specification includes the following drawings, which show the following contents:

[0033] Figure 1 It is a flow chart of a random vibration intensity evaluation method of a gearbox motor controller shielding plate and a copper bar of the present invention;

[0034] Figure 2 is a schematic diagram of the overall geometric model of the controller of the present invention;

[0035] Figure 3 is a schematic diagram of a controller bolt connection model of the present invention;

[0036] Figure 4 It is a schematic diagram of the common node grid of the controller pin and the board welding of the present invention;

[0037] The markings in the figure are:

[0038] 1. Cover plate; 2. Box cover; 3. Film capacitor; 4. Control board assembly; 5. Shielding plate; 6. Fuse assembly; 7. Copper busbar; 8. Copper busbar support; 9. PCBA adapter board; 10. Relay assembly; 11. Box body; 12. Driver board assembly; 13. Connector; 14. DC EMC filter assembly; 15. Support foot; 16. Bottom cover; 17. Connecting bolts. DETAILED DESCRIPTION

[0039] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0040] like Figure 1 As shown, the present invention discloses a method for evaluating the random vibration strength of a shielding plate and a copper bar of a gearbox motor controller, comprising the following steps:

[0041] S1: Establish the overall geometric model of the gearbox motor controller;

[0042] S2: Mesh each component in the controller and set material properties;

[0043] S3: Apply fixed constraints at the bolt connection holes between the support legs and the vehicle. S4: Calculate and extract the modal information of the controller within the set vibration frequency range;

[0044] S5: Apply the power spectrum density in the X, Y and Z directions respectively to determine whether the strength of the shielding plate and the copper bar meets the requirements within a certain probability range;

[0045] S6: Calculate the unit harmonic response in the X, Y and Z directions respectively, and apply loads to determine whether the fatigue of the shielding plate and the copper bar meets the requirements.

[0046] The following describes each of the above steps in detail.

[0047] For step S1: establish the overall geometric model of the gearbox motor controller.

[0048] like Figure 2 As shown, the controller as a whole comprises a cover plate 1, a box cover 2, a film capacitor 3, a control board assembly 4, a shielding plate 5, a fuse assembly 6, a copper bar 7, a copper bar support 8, a PCBA adapter board 9, a relay assembly 10, a box body 11, a drive board assembly 12, a connector 13, a DC EMC filter assembly 14, a support leg 15, a bottom cover 16, a connecting bolt 17 and a circuit board (not shown in the figure). The support leg 15 is connected to the box body 11, and a plurality of support legs 15 are provided. The bottom cover 16 is mounted on one end of the box body 11 by a connecting bolt 17. The box cover 2 is mounted on the other end of the box body 11, and the cover plate 1 is mounted on the box cover 2. The film capacitor 3, the control board assembly 4, the shielding plate 5, the fuse assembly 6, the copper bar 7, the copper bar support 8, the PCBA adapter board 9, the relay assembly 10, the drive board assembly 12, the connector 13, the DC EMC filter assembly 14 and the circuit board are located in the inner cavity of the box body 11. The shielding plate 5, the bottom cover 16, the PCB adapter plate 9 and the control board in the control board assembly 4 are all thin plate parts.

[0049] The support leg 15 is located outside the box body 11 . The support leg 15 is used to be connected to the vehicle. The support leg 15 is connected to the vehicle via bolts. Bolt connection holes for the bolts to pass through are arranged on the support leg 15 .

[0050] In the above step S1, the controller as a whole is modeled by three-dimensional software to obtain its overall geometric model.

[0051] In the above step S1, when establishing the three-dimensional model, the models of the control board assembly 4, fuse assembly 6, copper busbar support 8, relay assembly 10, drive board assembly 12, DC EMC filter assembly 14 and other components of the controller are simplified, for example, the process chamfers and fillets on each component are ignored.

[0052] In the above step S2, the specific method of meshing the components in the controller and setting the material properties is as follows: the support leg 15 is meshed with more than 3 layers of solid mesh; thin plate parts such as the shielding plate 5, the bottom cover 16, the PCB adapter plate 9 and the control board in the control board assembly 4 are meshed and set with high-order shell units; the interior of each component such as the control board assembly 4, the fuse assembly 6, the copper busbar support 8, the relay assembly 10, the drive board assembly 12 and the DC EMC filter assembly 14 are meshed and set with common nodes; the pin welding position such as Figure 3 The above meshing methods can reduce the number of meshes and improve the efficiency of finite element calculation without affecting the calculation accuracy.

[0053] Specifically, in the above step S2, the internal film capacitor 3, the circuit board and the connector are defined as mass units according to the center of gravity position, and the moment of inertia of the X / Y / Z axis is given to each component. The connecting bolt 17 adopts a bar unit, and the cross-section of the bar unit is defined by the nominal diameter of the bolt. The connecting bolt 17 and the surrounding components are connected by the rb2 unit. The bar unit is divided into two sections, and the two sections of the bar unit are respectively a bar unit at the bolt head of the connecting bolt 17 and a bar unit at the thread of the connecting bolt 17. The bar unit at the bolt head of the connecting bolt 17 is consistent with the axial length of the component through hole, and the bar unit at the thread of the connecting bolt 17 is consistent with the thread length position. The two sections of the bar unit are connected by a common node. The rb2 unit grabs each component at the connection bolt 17 (the bolt connection is usually an upper and lower structure, the upper structure is connected to the bolt head, and the lower structure is connected to the thread; the component here is to grab the surface adjacent to the upper structure and the bolt head and the surface connecting the upper structure and the lower structure. 1.5 times the bolt hole diameter, that is, the ring at 1.5 times the bolt hole diameter of the upper and lower sides of the upper structure; the bolt 17 is shown at the box 11 and the bottom cover 16) 1.5 times the washer (1.5 times the bolt hole diameter, 1.5 times the circle replacing the inner and outer diameter of the washer) outside the upper and lower bolt holes The mesh within the range of the ring area), the mesh within the bolt holes on the top surfaces of each component captured at the thread of the connecting bolt 17 (the bolt connection is usually an upper and lower structure, the upper structure is connected to the bolt head, and the lower structure is connected to the thread; the components here capture the ring 1.5 times the diameter of the bolt hole on the surface adjacent to the upper structure and the threaded hole of the lower structure; it is different from the upper and lower bolt holes mentioned above), the mesh within the range of 1.5 times the washer outside and at the thread position. This mesh capture method ensures that the contact area is fully covered, thereby improving the accuracy of the simulation. The rb2 unit and the bar unit are connected by common nodes, which means that on the contact interface, the nodes of the rb2 unit and the bar unit coincide, thereby ensuring the continuity of force and displacement. The specific connection method is as follows Figure 4 The above settings not only take into account the influence of the bolt's deadweight on the mode, but also reduce the number of grids and improve the calculation efficiency.

[0054] Through the above settings, the overall finite element model is established.

[0055] like Figure 1 As shown, in the above step S3, a fixed constraint is applied at the bolt connection hole where the support leg is installed with the whole vehicle.

[0056] like Figure 1 As shown, in the above step S4, the modal information of the controller within the set vibration frequency range is calculated and extracted.

[0057] Specifically, the upper limit of the random vibration frequency range is set to be no less than the upper limit of the random vibration test condition frequency range, and the lower limit is set to be twice the lower limit of the random vibration test condition frequency range.

[0058] like Figure 1 As shown, in the above step S5, the power spectrum density in the three directions of X, Y and Z is applied respectively to determine whether the strength of the shielding plate and the copper busbar meets the requirements within a certain probability range.

[0059] Specifically, in the above step S5, the damping is defined as 0.01; at the fixed constraints of the bolt connection holes between the support legs and the whole vehicle, the acceleration power spectrum density in the X, Y and Z directions is applied respectively to determine whether the equivalent stresses of the shielding plate and the copper busbar within the 3sigma probability range reach their respective tensile strengths.

[0060] like Figure 1 As shown, in the above step S6, the unit harmonic responses in the three directions of X, Y and Z are calculated respectively, and loads are applied to determine whether the fatigue of the shielding plate and the copper bar meets the requirements.

[0061] Specifically, in the above step S6, the damping is defined as 0.01; at the bolt connection hole fixing constraint between the support leg and the vehicle, a unit acceleration of 9810 mm / s in the X, Y and Z directions is applied respectively. 2 , calculate the unit harmonic response; after the calculation is completed, apply the power spectrum density coefficient corresponding to the unit acceleration to obtain the stress spectrum of the shielding plate and the copper busbar; introduce the SN curve (stress-life curve) to calculate the fatigue damage of the shielding plate and the copper busbar; compare the calculated fatigue damage of the shielding plate and the copper busbar with the design allowable value parameters of the shielding plate and the copper busbar to confirm whether the shielding plate and the copper busbar meet the requirements.

[0062] In the solution disclosed above, the order of step S5 and step S6 can be performed in parallel or swapped.

[0063] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A random vibration strength assessment method for the shielding plate and copper busbar of a gearbox motor controller, characterized in that: include: Establishing a geometric model of the gearbox motor controller as a whole; the controller as a whole comprises a copper bus, a support leg and a thin plate member, and the thin plate member comprises a shielding plate; Mesh each component in the controller and set material properties; Apply fixed constraints at the bolt connection holes where the support legs are installed with the vehicle; Calculate and extract the modal information of the controller within the set vibration frequency range; Apply the power spectrum density in the X, Y and Z directions respectively to determine whether the strength of the shielding plate and the copper bar meets the requirements within a certain probability range; The unit harmonic response in the X, Y and Z directions is calculated respectively, and loads are applied to determine whether the fatigue of the shielding plate and the copper bar meets the requirements.

2. The random vibration intensity evaluation method of the gearbox motor controller shielding plate and copper busbar according to claim 1 is characterized in that: The specific method of meshing each component in the controller as a whole and setting material properties is as follows: The support legs are divided into solid grids of more than 3 layers; The thin plate adopts high-order shell elements to perform mesh division and set material properties; Using common nodes to perform meshing and set material properties inside each component of the controller as a whole; The pin welding positions are all meshed and material properties are set using common nodes.

3. The random vibration intensity evaluation method of the gearbox motor controller shielding plate and copper busbar according to claim 2 is characterized in that: The controller as a whole includes a film capacitor, a circuit board and a connector. The film capacitor, the circuit board and the connector are defined as a mass unit according to the center position, and the inertia moment of each component is given to the X / Y / Z axis.

4. The random vibration intensity evaluation method of the gearbox motor controller shielding plate and copper busbar according to claim 2 is characterized in that: The components of the controller as a whole include a drive board component, a control board component, an IGBT component, a relay component, a fuse component and a DC EMC filter component.

5. The random vibration intensity evaluation method of the gearbox motor controller shielding plate and copper busbar according to any one of claims 2 to 4, characterized in that: The bolt adopts bar unit, and the cross section of the bar unit is defined by the nominal diameter of the bolt. The bolt and the surrounding parts are connected by rb2 unit.

6. The random vibration intensity evaluation method of the gearbox motor controller shielding plate and copper busbar according to claim 5 is characterized in that: The bar unit is divided into two sections. The bar unit at the bolt head is consistent with the axial length of the component through hole, and the bar unit at the thread of the bolt is consistent with the thread length position. The two sections of the bar unit are connected by a common node.

7. The random vibration intensity evaluation method of the gearbox motor controller shielding plate and copper busbar according to claim 6 is characterized in that: The rb2 unit captures the mesh within 1.5 times the washer outside the bolt hole on the upper and lower surfaces of each component at the bolt position, and captures the mesh within 1.5 times the washer outside the bolt hole on the top surface of each component and at the thread position at the thread. The rb2 unit and the bar unit are connected using common nodes.

8. The random vibration intensity evaluation method of the gearbox motor controller shielding plate and copper busbar according to any one of claims 1 to 7, characterized in that: Before the calculation and extraction of the modal information of the controller within the set vibration frequency range, the method further includes: The upper limit of the random vibration frequency range is set to be no less than the upper limit of the random vibration test condition frequency range, and the lower limit is set to be twice the lower limit of the random vibration test condition frequency range.

9. The random vibration intensity evaluation method of the gearbox motor controller shielding plate and copper busbar according to any one of claims 1 to 8, characterized in that: The specific method of applying load to calculate whether the random vibration fatigue strength of the gearbox motor controller shielding plate and the copper bar meets the requirements is: Define damping; At the bolt connection holes where the support legs and the vehicle are installed, unit accelerations in the X, Y and Z directions are applied to calculate the unit harmonic response. After the calculation is completed, the power spectrum density is applied to obtain the stress spectrum of the shielding plate and the copper busbar; The SN curve is introduced to calculate the fatigue damage of the shielding plate and the copper busbar; The calculated fatigue damage of the shielding plate and the copper busbar is compared with the design allowable value parameters of the shielding plate and the copper busbar to confirm whether the shielding plate and the copper busbar meet the requirements.

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